Characteristics of gasoline components
\r\n\tThis book is intended to provide a series of peer reviewed chapters that the guest editor believe will aid in increasing the quality of the research focus across the growing field of grain and seeds compound functionality research. Overall, the objective of this project is to serve as a reference book and as an excellent resource for students, researchers, and scientists interested and working in different functional aspects of grain and seed compounds, and particularly for the scientific community to encourage it to continue publishing their research findings on grain and seed and to provide basis for new research, and the area of sustainable crop production.
\r\n\t
Straight-run processing of petroleum (or crude oil) is the kind of processing where the material is distilled after being purified and is separated into fractions (or cuts), based on boiling range differences between its respective components, without modifying the chemical structure of its constituent compounds. Fractional distillation is typically carried out in two steps: under normal pressure and under reduced pressure. Figure 1 shows a simplified diagram for straight-run processing of petroleum.
Straight-run processing of petroleum – simplified diagram
Before processing, petroleum has a content of solid contaminants (up to 1.5 %) and water (up to 0.3 %). Part of insoluble contaminants and water are removed from petroleum by being left to stand (sedimentation). The process simply involves storage of petroleum in storage tanks for a certain length of time, during which the solids and part of its water content migrate to the bottom while the other solids dissolve in the water, forming a brine, which it is rather hard to remove. In that emulsion, the petroleum is the dispersion medium while water with salts is the disperse phase. Existing emulsion breaking methods are categorized into three groups:
mechanical methods – involve sedimentation, centrifugation, and filtration of fresh emulsions;
chemical methods – involving first of all the use of deemulsifiers, which are supposed to dissolve the adsorption film at the water interface;
electrical methods – involving the use of electrohydrators.
In all such groups, deemulsification involves the combining of small disperse water drops by overcoming surface tensions forces at the interface, to form drops big enough to be able to fall down the tank by gravitation. In industry, electrical methods are typically used, where the reactor has two flat electrodes installed in it, between which there is a voltage of about 30 kV. The water molecules move towards the respective electrodes and, as the electrode symbol changes, the molecules lose their electrical orientation and collide with one another, forming suitably large drops which fall down the tank. The resulting dewatered petroleum is taken at the top of the reactor. Electrohydration is carried out at an elevated temperature in a continuous manner.
The purified and degassed petroleum is made to flow into a tubular furnace to be heated to a temperature not higher than 370°C and then to the base of a first distillation tower (atmospheric column). The distillation tower is approximately 40 m high and comprises a number of so-called trays. Their shape depends on the rectification process parameters, the typical tray designs include: bubble cap, sieve, wave, West, cascade, Venturi, ejector, valve, and combinations of the above. The rectification process in the atmospheric tower is carried out at nearly-atmospheric pressures. After flowing into the tower, the hot petroleum is divided into fractions as follows: the consecutive fractions (in terms of density) evaporate and then condense on the respective tray groups, are then taken to heat exchangers (where their heat is transferred to the petroleum flowing into the furnace) and sent downstream.
Inside the column, there circulates a so-called “reflux", which may be of the hot (water or, less frequently, feedstock), cold, or circulating type. The reflux is supposed to keep sufficient temperatures, especially in the top regions of the column.
The products obtained in the atmospheric distillation tower include:
overhead fraction (which also functions as the circulating reflux;
side fractions (their amount and boiling ranges depend on the process parameters and design of column); typically, they include:
light gasoline fraction;
naphtha fraction;
kerosine fraction (jet fuels);
diesel fuel fraction;
spindle oil fraction.
distillation residue, also called mazut.
For a better fractionation of the gasoline fraction (to obtain medical benzin, extraction naphtha, painter’s naphtha), it is possible to re-rectify a portion on it in a separate atmospheric tower. Its design and processing regime are the same as described earlier. Distillation residue from that column is combined with the kerosine fraction. Rectification in each atmospheric tower takes place above the feed point for the gas phase but below the feed point for the liquid phase. In order to ensure appropriate rectification of the liquid phase, it is necessary to provide additional heat or another evaporating agent. Rectification in atmospheric towers is a continuous process.
A vacuum tower is another major component of a straight-run petroleum processing plant. It serves for distillation of the high-boiling distillation residue from the atmospheric tower, after heating it to 430°C in deep-vacuum conditions. In the vacuum towers of to-day, pressures in the evaporation region are in the range (1.99...2.27) kPa, compared with 0.66 kPa at the vapor outlet point. Atmospheric towers are 15-30 m high, their diameter is a max. of 12 m. The column is filled with bubble cap or sieve or valve-type trays; depending on the kind of product made in the vacuum column, the number of trays varies between 8...14 (if the product is used for catalytic cracking) and 38...42 (if the distillate is used for oil production).
Mazut, which flows into the column typically above tray 6, is combined with foam reducers (for instance, silicones at a concentration of 0.75 mg/dm3 of feedstock). Lower pressure, which is reduced by means of a system of so-called ejectors and condensers, leads to lower boiling ranges, enabling rectification of heavy mazut without decomposing it.
The vacuum tower products include: between one and three side fractions, a gas overhead fraction and the distillation residue called soft asphalt. After further straight-run or destructive processing, the side fractions are an important component for various engine oils and heating oils.
In addition, straight-run processing comprises a number of auxiliary treatments, enabling the various components to be separated from the distillation products. Such treatments include: crystallization and filtration, refining with the use of H2SO4 and selective solvent, dewaxing with the use of selective solvents and de-asphalting with propane.
Crystallization and filtration are intended to separate paraffins from the distillation cuts. The crystallized paraffins are then filtered off using a pressure press and filtration cloth. After the removal of paraffins, the oil fraction is further processed and the crude paraffin that results is used for making insulation materials, maintenance materials, or candles (after refining). Refining of the post-distillation fractions is intended to remove asphalts and resinous compounds, which are undesirable in further processing.
In order to remove acid oxygen-based compounds or some sulfur compounds, the petroleum products are subjected to refining by means of lye: it reacts with acidic compounds, forming respective water-soluble salts. Part of the compounds remain in the refined product and can only be removed therefrom by washing with water. The oils are refined using weak sodium hydroxide solutions. The process is carried out at elevated temperatures to prevent the formation of emulsions which it would otherwise be hard to break.
In the process of neutralization of the oil distillates with lye, the napthene acid content of the distillate initially reacts with sodium hydroxide to form soaps, which dissolve in aqueous lye solutions whereby they are removed from the distillate; the emulsions formed then are usually not very stable. Stable emulsions are formed after another water-washing operation. This is due to the presence in the oil of resinous products which, in a dispersed form, are hydrophobic emulsifiers. Owing to the presence of high levels of hydrophilic emulsifiers, their activity as hydrophilic emulsifiers is not manifested during neutralization; on the other hand, when washing with water, the hydrophobic emulsifiers are not separated from the oil along with the waste lye and their effect shows very well. The phenomenon is observed when refining oils having a high content of tars and asphalts and a high content of oxidation products. The hydrophobic emulsions formed then may be separated by heating the distillates to high temperatures, by adding a solution of hydrophilic naphthene soaps, or by treatment with the use of weak solutions of mineral acids, which destroy the emulsifier’s interface films.
Refining the kerosine fractions with solvents is based on the choice of a suitable solvent which is able to dissolve in different ways the desirable and the undesirable components of the refined product. Selective solvents are expected to be able to readily dissolve, to be selective and stable, to form readily separating extract and raffinate phases, to be easily regenerated, to resists corrosion in operating conditions, and to have non-toxic properties.
The essential parameters which determine the level of refining include temperature and the solvent-to-material ratio. The choice of temperature for the refining process depends on the critical temperature of solubility for a given mixture. Refining with the use of selective solvents is feasible in those temperature ranges where a two-phase system exists: the raffinate solution (containing a trace amount of solvent) and the extract solution (comprising mainly the solvent and the undesirable components of the starting raw material which are dissolved in the solvent). The critical solubility temperature depends on the structure of hydrocarbon molecules: their critical solubility temperature is lower (and going down rapidly) for higher numbers of rings in the hydrocarbons but is lower for longer alkyl lengths. Naphthenes with five-member molecules will better reduce the critical temperature of solubility, compared with six-member molecules. In the case of aromatic hydrocarbons and naphthenes with same structures, for same solvent, critical temperature of solubility of aromatic hydrocarbons is much lower than that of naphthenes. Naphthene-aromatic hydrocarbons have lower critical temperatures of solubility, compared with naphthene hydrocarbons having a similar structure. Normal paraffins have the highest critical temperature of solubility. The value of critical temperature of solubility and kerosine fractions in a solvent is affected also by the solvent’s properties: for instance, critical temperature of solubility of hydrocarbons in nitrobenzene is much lower than that in phenol, but is lower in phenol compared with that in furfurol.
Solubility of substances in solvents depends on attractive forces between the molecules of the solvent and the solute. Attraction between molecules takes place due to the Van der Waals forces and hydrogen bonds. In view of the fact that kerosine fractions comprise mainly nonpolar hydrocarbons, selective extraction of undesirable components is only possible in the case of Deby\'s effect, that is, co-operation of induced dipols which are formed in non-polar molecules under the effect of the electric field of polar solvent’s molecules. The highest polarizability is shown by aromatic hydrocarbons, the lowest by naphthenes and paraffins. Therefore, aromatic hydrocarbons readily submit to the action of the electric field of solvents, which leads to the formation in their molecules of an induced dipol moment, resulting in their readily dissolving in polar solvents.
In addition to the refining temperature and type of solvent, the degree of extraction of undesirable components depends also on its amount that is indispensable for extraction. On the other hand, the amount of solvent depends on its properties, chemical composition of the starting material, the desirable refining degree, and on the extraction method.
Selective refining by means of furfurol is a method for removing aromatic hydrocarbons from vacuum petroleum distillates, and is used as a base oil production step. Furfurol is a polar substance with a high dipol moment. It is able to selectively dissolve hydrocarbons by inducing the dipol moment in the hydrocarbon molecules which are contacted with furfurol. It is useful as a solvent in selective refining processes because of the following advantages:
high density and lack of tendency to form foams or emulsions; these properties facilitates phase separation between the raffinate extract solutions;
low freeze point: therefore, its mixtures are easier to handle at low temperatures, requiring no extra care or devices;
large difference between the critical temperatures of solubility for paraffinic and aromatic compounds.
On the other hand, furfural has the following disadvantages:
low resistance to oxidation at high temperatures, both in alkaline and acidic environments,
formation of acidic oxidation products and high-molecular products of polycondensation;
high toxicity.
In the process of selective refining with furfurol, aromatic compounds are removed from the oil more readily than paraffins, compounds with high viscosity. Hence, a more aromatic compound requires less solvent and lower temperatures to be entirely dissolved. Therefore, by selecting suitable extraction temperatures and solvent-to-material ratio, it is possible to remove either only aromatic compounds from the raw material or – after modification of extraction conditions – to remove mixed compounds as well.
Adsorption as a refining process is currently used, first of all, in the finishing of light kerosine cuts, lubricating oils, specialty oils, and paraffins.
The role of adsorption in the refining of petroleum products is in the adsorption of asphaltenes, resins, diolefins, acids, etc. on the adsorbent surface, consequently providing a finished product with improved color and odor, and stable physico-chemical and performance properties.
The adsorption refining process is carried out either by the cold or hot method, using percolation (where adsorbent pellets are used) or by the contact method, using so-called decolorizing earths (adsorbents in the pulverized form, obtained from natural aluminosilicates).
The following materials are used in the refining process:
sorbents, obtained by thermal or thermal-chemical modification of natural mineral raw materials (aluminosilicates);
synthetic sorbents, such as: silica gel or alumina;
active carbon.
When selecting s suitable sorbent, care is taken not only about the efficiency of regeneration, connected with improving the properties of oil, but also about the cost-efficiency of the process. To select the most suitable sorbent, it is necessary to consider some of its properties, first of all, its refining capacity, selectivity, chemical properties, mechanical strength, costs, availability, possible reactivation, and disposal.
Destructive processing of petroleum involves modification of the structure of hydrocarbons contained in the fractions obtained from the straight-run processing of petroleum. Such modification is intended to improve intermediates for use in final product blending. Destructive processing cannot be carried out with the omission of straight-run processing. The essential process groups included in destructive processing of petroleum are discussed below.
Thermal cracking is a process in which large hydrocarbon molecules are broken to form light unsaturated hydrocarbons in high-temperature conditions.
Thermal cracking comprises three groups of processes:
Cracking of liquid raw materials at high pressures (1961.3...6864.6) kPa in the temperature range (470...540)°C to obtain gasoline. The process is intended to obtain a higher amount of fuels at the cost of oil fractions. Gasoline can be obtained from the post-distillation side-fractions in atmospheric and vacuum towers, while heating oils can be obtained from the distillation residue (soft asphalt) in a vacuum tower. The process to obtain heating oils, carried out in mild conditions, is called visbreaking;
Low-pressure cracking – also called coking, or destructive distillation. The process is carried out at temperatures in the range (450...550)°C. It is intended to provide light-colored products with a high hydrogen content, such as gasoline, diesel fuels or gases, as a result of decarbonization (concentrating asphalts and resins into so-called “petroleum coke”). The coke product is often a target product, intended for making, for instance, coatings for electrodes. The coking process is carried out as shown in the diagram below and may be interrupted or slowed down at any time by injection of an extra amount of cold raw material.
Thermal cracking in the most severe conditions: pyrolysis. The process is carried out at temperatures in the range (670...800)°C (though the process temperature may be as high as 1200°C). The process is intended mainly to provide unsaturated gases, usually ethylene, for use in petrochemical syntheses. The process also provides aromatic hydrocarbons such as benzene, toluene, xylenes, or naphthalene, and so-called post-pyrolytic gasoline which is a component for automotive gasoline, though they are only to be considered as side products.
In addition to the above, there exist a number of intermediate thermal cracking processes, for instance, vapor phase cracking in low pressure conditions at a temperature of 600°C to produce gasoline, or coking of the residue in severe conditions in order to increase the amount of gas and aromatization of liquid products.
Catalytic or thermocatalytic cracking processes are carried out at high temperatures in the presence of catalysts. They are intended to provide light products with good quality at the cost of heavy products (mainly gasoline and diesel fuels) or to improve the quality of other distillation products.
Gasoline and diesel fuels, obtained at temperatures in the range (450...500)°C in the presence of an aluminosilicate catalyst, are characterized by high resistance to decomposition and oxidation processes (mainly gasoline) and high purity. The mechanism of catalytic cracking is reverse to that of thermal cracking and leads to highly saturated hydrocarbons.
Gasoline reforming has been isolated from the catalytic cracking and is a separate process, intended to improve the gasoline fractions by their aromatization and purification to remove sulfur compounds therefrom. Pure aromatic hydrocarbons such as benzene, toluene, xylenes, can be obtained from the aromatized gasoline for petrochemical synthesis after its suitable separation. Moreover, reforming provides hydrogen for hydrogen processes. Depending on its variant, the reforming process uses a number of catalysts (Co, Ni, Mo, Pt, Fe), usually aluminosilicates. The process temperature is around 550°C. The essential reactions taking place during gasoline reforming include dehydrogenation of cycloalkanes (naphthenes), dehydroisomerization of naphthenes, and dehydrocyclization of alkanes (paraffins). These reactions are accompanied by isomerization and hydrocracking of paraffins. The essential reactions generate free hydrogen, therefore, such reactions as desulfurization and saturation of alkenes take place as well.
Fluidized-Bed Catalytic Cracking (FBCC) of de-asphalted vacuum and heavy petroleum cuts, in the presence of aluminosilicate catalysts (typically zeolites), is one of the major methods for deep processing of petroleum that are used in advanced refineries. The process is highly complex in terms of equipment and, accordingly, involves relatively high investment costs. On the other hand, the use of the process unit is justified in economic terms, since on average, only about 50 % (m/m) of petroleum is distilled-off at an atmospheric pressure. The petroleum fraction that results from vacuum distillation, having a boiling range of (350...500)°C and constituting typically 25 % of its weight, is a perfect feedstock for the FBCC plant, for making valuable components of engine fuels and light olefins for use in synthetic plastics (polyethylene, polypropylene, rubbers, etc).
Cracking of high-molecular hydrocarbons causes breaking of intermolecular bonds, which is accompanied by dehydrogenation and hydrogenation, comprising hydrogen transfer reactions. The bonds between carbon atoms are broken in irreversible reactions. Out of a great variety of bonds between the atoms, those with the lowest energy are the easiest to break. The elementary energy of C-C bonds in paraffins is 265 kJ/mol, for C-H bonds it is 360 kJ/mol, and that of C-C bonds in aromatic compounds is (500...610) kJ/mol, therefore, paraffins are most frequently subjected to cracking. Hydrogen transfer reactions contribute to the formation of gasoline compounds as saturated compounds, though at the cost of formation of those with a low hydrogen content, including coke. During the cracking process, owing to thermodynamic conditions, polymerization of olefins – though only insignificant – is the first phase in the formation of aromatic compounds and coke.
The essential reaction leading to the formation of coke is the condensation of aromatic hydrocarbons with olefins. Therefore, naphthenes and naphthene-paraffin compounds are the most preferable raw materials for fluidized-bed cracking. On the other hand, aromatic feedstock hinders the cracking process, favoring the formation of coke.
During the cracking process, primary reactions are accompanied by a number of secondary ones which become more and more intensified: such processes include polymerization, aromatization, isomerization, alkylation and dealkylation. Catalytic cracking takes place at lower temperatures, compared with thermal cracking but the amount of coke being formed in it is much more limited. The aluminosilicate catalysts used in the process accelerate the most desirable reactions: the rate of cracking of paraffins is 10 times as high, compared with that in a purely thermal process, conversion of naphthenes is 1000 times as fast, and that of side-chain aromatics is 10,000 times as fast.
The cracking feedstock contains more or less of metals (mainly vanadium, nickel, and iron), sulfur and nitrogen, in addition to oxygen. Organometallic links are broken and their metals accumulate on the catalyst, leading to its deactivation, accelerated formation of coke, and higher amount of gaseous hydrocarbons.
Cracking of aromatic feedstock is characterized by an increased efficiency of the formation of aromatic hydrocarbons with a considerable admixture of olefins, in addition to the higher amount of coke. A naphthene feedstock produces a top quality gasoline as the result of isomerization and aromatization reactions.
A fluidized-bed catalytic cracking plant is composed essentially of a vertical-tube reactor, raising the catalyst and raw material (the basic process zone) and a regenerator with pipes carrying a spent and regenerated aluminum-silicon oxide system. At the bottom of the vertical tube, the strongly pulverized catalyst is mixed with the – nearly entirely evaporated – heavy hydrocarbon feed; cracking takes place as the feed flows upwards at the rate of (4...12) m/sec at a pressure in the range (0.8...1;5) bar, at a temperature typically in the range (480...530)°C. The cracking of heavy petroleum feedstocks is accompanied by the formation of coke: it accumulates on the catalyst, blocking its active sites. In such conditions, it is gravitationally carried into a regenerator to remove the coke by burning, typically at temperatures in the range (635...650)°C.
The naphtha cut from the FBCC plant is the main source of sulfur being carried into the final gasoline products during the blending process. In the global refinery industry, the level of sulfur in nahptha obtained by FBCC is reduced by the following methods:
pre-treatment of the FBCC feedstock using a hydrogen-catalyst method for the removal of the entrained sulfur;
increasing the conversion of organic sulfur compounds into hydrogen sulfide during FBCC;
processing the FBCC product by distillation with absorption.
The highest percentage of sulfur is concentrated in the highest-boiling gasoline fraction from FBCC. Therefore, lowering the final boiling range of that fraction is the obvious method to reduce its sulfur content. The available techniques include the following:
dropping part of naphtha into light diesel fuel; on the other hand, rejecting part of naphtha leads to higher quantities of light oil being collected but reduces its boiling range, changes the heat load of the light oil (part of which is recirculated within the main rectifying column) and degrades part of the naphtha to the medium distillate range;
collecting separately the heavier naphtha cut as part of the overall distillation of FBCC products; however, this changes product proportions, operation of the major fractionating column, and operation of the gas absorption system.
Hydrogen-based processes are thermo-catalytic processes, carried out at free-hydrogen pressure conditions. There are three different variants of hydrogen-based processes, depending on the degree of conversion; only those relating to the production of fuel components will be discussed later in this chapter.
A hydrocracking plant usually comprises the following units: hydrocracking of vacuum distillates, hydrogen generation, and hydrogen recovery from post-production gas. The process is intended to handle vacuum distillates from the pipe-tower distillation system with a boiling range (330...575)°C and provide desulfurized products having lower molecular weights and lower boiling ranges.
The process of technology in the plant is divided into the following steps: hydrodesulfurization, hydrocracking, and fractionation of hydrocracking products. Hydrodesulfurization and hydrocracking take place in the presence of catalysts at elevated temperatures (340...450)°C, at a hydrogen pressure of about 15 MPa. The hydrodesulfurization reaction is accompanied by the removal of other contaminants from the feedstock (including nitrogen, chlorine, oxygen, metals), hydrogenation of olefins, and part of aromatic compounds. The main reason why the metals are removed is to protect the catalyst from irreversible deactivation taking place as metal compounds accumulate on the catalyst’s surface.
The mechanisms of hydrocracking include two basic conversions: cracking of hydrocarbons, and hydrogenation of the products of catalytic cracking, typically in the presence of an aluminosilicate-based nickel-tungsten catalyst. The post-reaction mixture provides the following fractions: liquid gas, light gasoline, middle gasoline, aviation fuel, light diesel fuel, heavy diesel fuel, and a desulfurized but non-cracked vacuum oil fraction which is a feedstock to the fluidized-bed catalytic cracking (FBCC) plant.
Hydrocracking has the essential advantage of providing top quality products which, unlike similar products obtained by catalytic cracking, have a better stability because they contain no olefins or dienes. Moreover, the content of sulfur and nitrogen in the gasoline and diesel fuel products obtained is low enough to enable them to be used directly in obtaining environmentally-friendly blends of final products.
Destructive hydrogenation is a process in which a solid and a liquid feedstock is cracked under a hydrogen pressure in the range (29419.8...68646.2) kPa at a temperature in the range (420...500)°C in the presence of catalysts (Fe, W, Mo, Ni). The process is intended to produce gasoline products, but sometimes also diesel fuels from coal, bituminous shale, tar and soft asphalt.
The processing of light fractions and gases is intended to provide saturated components of fuels or products for petrochemical syntheses. The process includes the following reactions, running in the presence of suitable catalysts:
polymerization of gaseous alkenes;
alkylation of gaseous and liquid isoparaffins with alkenes;
alkylation of aromatic compounds with alkenes;
dehydrogenation of butane and pentane fractions;
isomerization of butane and light hydrocarbons from gasoline fractions.
Although rather energy-consuming, the catalytic processing of these gases enables elimination of distillation losses, that is, flare combustion of gases while increasing the obtained amounts of gasoline.
Soft-asphalt utilization technology includes thermal methods (mainly coking and visbreaking), extraction, hydrogen-based methods (such as hydrodesulfurization and hydrocracking), and gasification.
Among these methods, hydrogen-based processes and gasification are believed to have the highest potential and be most environmentally-friendly, although they require the highest investment costs.
Lurgi offers a Multi Purpose Gasification (MPG) technology for gasification of hydrocarbon feedstock. Its main advantages include the possibility to handle low-quality/high-viscosity heavy fractions, also with a content of sludge, mud, and waste coke, and the possibility to handle raw materials with a high sulfur content. The oxygen-steam feedstock gasification unit comprises a burner and a reactor, gas cooling section, and a system for the removal of ash, metals, soot, and liquid waste.
Gasification is an autothermal process, controlled by the oxygen-to-steam ratio, running according to the following reaction:
The ratio of CO and H2 generated in syngas depends on the composition of raw materials, oxygen-to-steam ratio, and parameters of gasification. Non-catalytic semi-combustion of hydrocarbons in the MPG technology takes place in an empty reactor lined with a refractory material, selected for a load resulting from the ash content in the feedstock. The material is fed into the reactor through the burner at the top of the reactor. The burner accepts liquid feeds with the highest viscosities as well as emulsions and sludge with particles the size of several millimeters. The feed and an oxidizer are heated and mixed with steam as a moderator before the burner. The burner and the reactor are “fine-tuned”, or adapted, to each other by dynamic simulation to entirely mix the reactants in as small a volume as possible and, in this way gasification of the raw materials is complete. The hot crude gas from the reactor is quenched with water originating from the ash and soot removal unit. The water is injected in a radial arrangement into the quenching-ring zone, where it is quenched, or cooled down rapidly, into the form of glassy beads the size of (1...2) mm. The beads accumulate at the bottom of the separator and are discharged through a hopper. The glassy slag carries a majority of heavy metal content and water-insoluble components. Further cooling takes place in a medium-pressure steam boiler, generating steam in the range (1.5...3.0) MPa. Final cooling takes place in a water cooler, then the gas is sent to the acid gas removal unit.
The crude syngas portion which is intended for use in hydrogen generator, passing by the steam boiler, is sent straight into the CO catalytic conversion unit, working according to the following reaction:
Carbon dioxide is removed by means of cooled methanol.
The syngas, generated during gasification of hydrocarbons, contains a certain amount of free carbon (soot), typically about 0.8 % (m/m) on the feedstock basis. The soot particles are removed from the gas together with ash, mainly in the Venturi gas srubber, located after the quenching section. Sludge with a content of soot is collected together with condensates from the steam boiler and from the cooler-gas scrubber, and is sent to the ash (and metals) removal section. The sludge, with soot from gasification, is depressured batchwise to an atmospheric pressure in the sludge tank before being filtered.
The German refinery PCK Schwedt and Toyo Engineering Corporation from Japan developed one of the most advanced processes of technology for processing the residue from vacuum distillation of petroleum: HSC-DESUS (HSC-High Conversion Soaker Cracking). Compared with conventional visbreaking, it is characterized by a very high conversion and the residue has a stable quality. A variety of intermediate products can be used as a feedstock with a high content of sulfur and heavy metals (including heavy oil and bitumens from oil sands as well as residues from the production of lubricating oil). Post-cracking distillates from that technology are usually light or heavy gas oils having a lower content of unsaturated compounds than that in distillates from coking processes.
In the HSC technology, the feedstock is heated to a temperature in the range 440…460°C, depending on the desired conversion in the soaking drum. Cracking in the furnace is minimized by using high flow rates. A reactant stream from the furnace is made to flow into the soaking drum in which the residence time is long enough to provide desired conversions. The soaking drum operates at an atmospheric pressure, and its bottom section is filled with stripping steam. In the soaking drum, the raw material flows downward, through perforated plates. Steam along with cracking gas and distillate vapor flow through the perforated plates upward; their flow is countercurrent, compared with that of the raw material. The temperature in the soaking drum is highest at the top and becomes lower in its lower sections due to the adiabatic cracking reaction and stripping of the cracked substrate. The liquid from the bottom is pumped out and quenched in the heat exchanger to a temperature of less than 350°C. Vapor from the soaking drum flows into the rectifying column in which desirable intermediate fractions are formed, including heavy vacuum oil.
The soaking drum contains a stable homogeneous dispersion of asphaltenes in the residue, even at much higher conversions than in conventional visbreaking.
Distillates from conventional visbreaking, which is regarded as a first step in the processing of soft asphalt, and from the second step (the HSC plant) are then subjected to hydrogen treatment in the DESUS plant. The feed, after a multi-step heat exchange and after being mixed with hydrogen, is made to flow through the furnace and into a fixed-bed reactor. This is the hydrofining reactor, where sulfur, nitrogen, and oxygen are removed from the liquid reactants and hydrocracking takes place, with conversions of around 30 % (m/m). The post-reaction mixture flows through heat exchangers first into the hot separator, then the vapor and gas flow through a heat exchanger and two-step coolers into a cold separator for the separation of the liquid/gas phases. Liquid products are sent downstream to rectification, except that light fractions are subjected to stabilization.
The process to make synthetic fuels from syngas is known as the Fischer-Tropsch synthesis and was first used commercially in the 1940’s. The process to make engine fuels from a gas which contains a mixture of carbon monoxide and hydrogen, in the presence of cobalt and iron catalysts runs according to the following reaction:
the cobalt catalyst
the iron catalyst
The process comprises:
syngas production by oxygen-steam gasification of coal, or by the catalytic semi-combustion or catalytic reforming (or both processes) of natural gas in the presence of steam;
removal of sulfur and carbon dioxide;
catalytic synthesis of carbon monoxide and hydrogen to form hydrocarbons;
distillation and treatment of the resulting intermediate products to obtain: liquefied gas, gasoline, jet fuels, diesel fuel, and paraffins.
The first American plant using the Fischer-Tropsch technology was built, in 1951, in Brownsville, Texas, by Carthage Hydrocol Company. It was based on a desulfurized natural gas. The plant was composed of two reactors (diameter 5.1 m, height 24 m), packed with 200 Mg of a fluid-bed iron catalyst each. A simplified diagram of the process is shown in Fig. 2. The oxygen generating plant supplied 1800 Mg O2 per day into the generator of catalytic semi-combustion of methane. The whole process was carried out at 3 MPa. Carbon dioxide was removed from syngas using a water jet.
Water, as a coolant, was made to flow through coolers located in the catalyst bed. Heat, generated during the reaction, was used for making steam. Gas and synthesis products were collected at the top of the reactor, carrying along the fine dust of the catalyst after removing it downstream by means of cyclones. The condensing portion of hydrocarbons and oxygen compounds was chilled and washed out with water. Lighter hydrocarbons were removed using an absorption-desorption system. C3 and C4 olefins were polymerized catalytically, obtaining gasoline which was then refined.
The resulting liquid products were composed of 25 % oxygen compounds and 75 % hydrocarbons. Gasoline after final treatment had a high olefin content and its octane number was 85.
Simplified diagram of the Hydrocol plant.
In 1955, in Sasolburg, South Africa, a coal-based plant using the Fischer-Tropsch synthesis was started. The raw material, named SASOL, is a poorly-sintering type of coal, containing about 25 % ash and 10 % water, its heat of combustion is 23,000 kJ/kg. Fig. 3 shows a general diagram of the process to obtain synthetic fuels in the Sasolburg plant.
Coal is crushed into finer pieces and then divided into three categories. The smallest pieces are used in the power station in four boilers, each of a capacity of 160 tons of steam per hour. After purification, the gas at a pressure 2.5 MPa is separated into two streams: one stream is sent to the synthesis unit which is equipped with revamped fixed-bed cylindrical reactors (each has a heat exchanger, cooler and blower enabling the gas to be recirculated). The other gas stream is made to flow to fluidized-bed reactors which are supplied with the gas obtained from conversion of the C1 and C2 hydrocarbons being made at the same plant. Each reactor in the synthesis plant is provided with approx. 20,000 m3 of syngas per hour. The gas conversion is in the range (50...60) %.
A majority of the products obtained in the synthetic plant are high-boiling hydrocarbons. The fluidized-bed reactors produce mainly gasoline.
A block diagram of the synthetic fuel plant in Sasolburg (source: own elaboration on the basis of company materials)
At present, the synthesis of methanol is carried out globally starting from a mixture of carbon monoxide and dioxide and hydrogen in the presence of catalysts which typically contain Cu-Zn-Al or Cu-Zn-Cr at a pressure in the range (5...10) MPa at a temperature in the range 240…275°C, according to the following reaction:
and, in part:
The process selectivity is enormously high, therefore, only a maximum of 0.5 % (m/m) of side products (in addition to water) is made.
A diagram of the complete methanol plant, based on natural gas or biogas from a municipal waste dump or anaerobic biomass fermentation tanks, is shown in Fig. 4. The methane or biogas is heated in the central furnace to approx. 420°C and made to flow into a desulfurization reactor which is packed with zinc oxide beads (ZnO+H2S → ZnS+H2O). From the reactor, the gas flows into the saturator (scrubber) to be saturated with steam. The saturator is supplied with a mixture of hot water from the distillation section and from the process condensate tank. Methane is heated in the respective apparatuses to about 800°C after being saturated with more steam (live steam) to form the desired mixture, and then directed into the reforming unit I° for the endothermal reaction CH4+H2O → CO+3H2 to take place on the Ni/γ-Al2O3 catalyst. If a biogas with 60 % CH4 and 40 % CO2 is used for the synthesis of methanol, then the reaction CH4+CO2 → 2CO+2H2 takes place additionally. Approximately 10 % (v/v) of methane is not converted, therefore, the reaction mixture is sent into the reactor II° for a strongly exothermal semi-combustion of CH4 to take place with participation of a strictly measured amount of oxygen on a nickel catalyst, according to the reaction:
A syngas at nearly 900°C is then made to flow through a boiler which generates compressed steam for the methanol plant, and is combined with hydrogen, separated from fuel gas (post-production gas) by Pressure Swing Adsorption (PSA).
A diagram of the methanol plant based on natural gas or biogas at Lurgi Ől-Gas (source: own elaboration on the basis of company materials) 1 – central gas-fired heater, 2 – methane desulfurization reactor with a ZnO catalyst, 3 – saturator, 4 – stage 1 reactor for methane steam reforming over a Ni catalyst, 5 – stage 2 reactor for methane reforming with the use of oxygen, 6 – water evaporator, 7 – water separator, 8 – turbocompressor, 9 – stage 1 reactor for methanol synthesis, 10 – stage 2 reactor for methanol synthesis, 11 – methanol recovery from unreacted syngas, 12 – 3-column distillation of raw methanol, 13 – hydrogen recovery from waste gases, PSA method, 14 – steam turbine which drives the turbocompressors of syngas and recycle gas, 15 – heat exchanger, 16 – cooler, 17 – water-steam separator
Then, it is sent into the turbo-compressor to obtain a pressure in the range (5...10) MPa and is combined with the unreacted reactant being recirculated from the methanol separator, and sent to two serially-connected methanol synthesis reactors. After the second synthesis reactor, the post-reaction mixture flows through the heat exchanger and water-cooled methanol condenser into the product separator. From the bottom part of the product separator, a crude methanol flows through pressure reduction valves and into three serially-connected rectifying columns. After the last rectifying column in the series, the purity of the methanol product is a minimum of 99.99 %. A portion of the unconverted post-process gas is recirculated for another synthesis of CH3OH, while another portion is sent through the PSA system (for recovery of hydrogen) into the fuel gas network and then into the central furnace. Bleeding a portion of the unconverted post-process gas continuously enables the inert content in circulation (N2+CH4) to be kept at a stable level of approximately 15 % (v/v).The first step, in which a crude methanol is neutralized using an aqueous soda lye solution, is followed by oxidation of aldehydes and iron cabonyls using an aqueous potassium permanganate solution. This results in the formation of a sludge which comprises manganese dioxide and other solids and is removed by filtration. The crude methanol is refined by distillation in two or three rectifying columns. For a two-column system, two process variants are possible: either both columns operate at an atmospheric pressure, or one operates at an atmospheric pressure while the other does at an elevated pressure.
The components of crude methanol are divided into three essential groups: light components, ethanol, and higher alcohols. Low-boiling compounds, having boiling points lower than or close to that of methanol, are removed along with the dissolved gases from the synthesis plant (H2, CO, CO2, CH4 etc.) in the first column. It is also referred to as the extraction column, with water being the extraction agent, which differentiates the liquid phase activity coefficients of the major components. The scope of changes in the activities of the respective components is determined by the quantity of the solvent required.
The crude feed is pre-treated with chemicals (NaOH, KMnO4), then heated to a boiling range and made to flow into the middle section of the extraction column. Extraction water, which is recirculated from the bottom section of the second rectifying column, is fed to the top of the extraction column. When extracting, the water is cooled down in the heat exchanger by the flowing crude methanol feed. Vapors from the extraction column, flowing upwards, carry along all the volatiles and a small amount of methanol vapor with water. Most of the methanol, water, and of less volatile components are condensed in the condenser and recirculated as the reflux through the separator and into the extraction column, the other ones escape to the fuel gas network or to the flare.
After extraction distillation, the crude methanol from the column bottom contains roughly 50% (m/m) CH3OH. The volume of the extractant to be added depends on the amount of contaminants as actually found in the crude feed and as shown in product specifications.
The second rectifying column is called the refining column: its main function is to separate water and high-boiling compounds from methanol being the principal product. Higher alcohols have a maximum concentration at the bottom of the column, below the feed point. Therefore, that part of the column comprises alternative points for carrying out higher alcohols from the system. The higher alcohols, if being carried out with the vapor stream, must be cooled down, condensed and sent into the separator. In addition to the higher alcohols and high-boiling components, the stream has a content of methanol, water, and small amounts of ethanol. If the stream is carried out from the lower trays of the stripping section or as a “liquid blow”, it may have a significant water content and is likely to become separated into two phases if allowed to stand. The light phase (or the organic phase) is a quite valuable fuel and may be used as a fuel for a furnace (methane reforming reactor, or steam boiler). The aqueous phase may be drained and disposed of as a chemical liquid waste.
In a two-column process system, the pure methanol is collected at the top of the refining column. Typically, it is collected between trays number 4 and 6, counting from the top down. That section has 4 to 6 trays at the top (pasteurization section) and is designed to concentrate low-boiling components, which penetrate through the bottom of the extraction column. A small volume of the total condensate, which is obtained at the top, is intentionally “blown out" or recirculated into the first column for such trace amounts of minor contaminants to be finally taken to the top of the system and out.
With the second column operating as a pressure column, part of the vapor being collected at the top may be used to provide heat to the first distillation column. However, at higher pressures, the difference between relative volatilities for the respective components is lower, therefore, for same product purities and same heat loads in the evaporator, the pressure column needs more trays.
In a three-column methanol rectification system, the third column is designed to separate methanol from ethanol. One of the methods to remove ethanol is by “blowing out" a small stream above the feed tray in the refining column, or by collecting an ethanol-methanol mixture at the top of the refining column, followed by separation of the two components in the third column. The feed to that column contains nearly all of the ethanol present in the feedstock (crude methanol) plus the methanol product. Water and trace amounts of higher alcohols are removed from the column together with ethanol while pure methanol is collected overhead. The pasteurization section is located above the product collection point.
Gasoline is a hydrocarbon mixture of roughly 100 of various compounds, obtained by the straight-run and destructive processing of petroleum. The fractions, found in gasoline, include the paraffin fraction (40...65)% (V/V), naphthene fraction (20...35)% (V/V) and aromatic fraction: (8...20)% (V/V).
Taking into account the desirable method of combustion, gasoline should preferably contain large amounts of aromatic hydrocarbons, obtained mainly by reforming and partly by pyrolysis. Very important components – especially in aviation fuels – are mixtures of hydrocarbons obtained in isomerization and alkylation processes (isoparaffins). Highly resistant to knocking combustion, they have the added advantage of a sufficiently high calorific value.
All the components that are required for gasoline blending are obtained in the respective types of refining processes and are combined in the blending unit in accordance with process requirements for the specific gasoline types. Major components of gasoline are listed in Table 1. The respective components are blended so as to obtain a final product (commercial gasoline) which complies with the requirements of applicable standards.
Most of those qualitative parameters of fuels are only approximate because their fractional and chemical composition is very complex. Numerical values for the respective qualitative parameters are selected in a manner which, in as far as possible, enables compliance with performance requirements, resulting from the design and mode of operation of spontaneous-ignition engines fuelled by such blends.
\n\t\t\t\tComponent\n\t\t\t | \n\t\t\t\n\t\t\t\tBoiling point/range [°C]\n\t\t\t | \n\t\t\t\n\t\t\t\tRON\n\t\t\t | \n\t\t\t\n\t\t\t\tFunction or use\n\t\t\t | \n\t\t
Base cut from distillation | \n\t\t\t45 ÷ 195 | \n\t\t\t40 ÷ 54 | \n\t\t\tEssential component of gasoline | \n\t\t
Butane | \n\t\t\t0 | \n\t\t\t95 | \n\t\t\tFacilitates cold engine start, component of automotive gasoline | \n\t\t
Pentane-hexane fraction | \n\t\t\t27 ÷ 65 | \n\t\t\t45 ÷ 93 | \n\t\t\tEnables continuous combustion during startup, when present in automotive and aviation gasoline types | \n\t\t
Light distillate | \n\t\t\t65 ÷ 90 | \n\t\t\t- | \n\t\t\tsame as above | \n\t\t
Reforming product: - complete | \n\t\t\t- | \n\t\t\t- | \n\t\t\tMajor component of automotive and aviation gasoline types, resistant to detonation combustion | \n\t\t
- de-aromatized | \n\t\t\t45 ÷ 200 | \n\t\t\t92÷ 101 | \n\t\t|
- de-xylenated | \n\t\t\t- | \n\t\t\t- | \n\t\t|
- refined reformate | \n\t\t\t- | \n\t\t\t- | \n\t\t|
Hydrocracking fraction | \n\t\t\t40 ÷ 200 | \n\t\t\t72 ÷ 85 | \n\t\t\tComponent of automotive and aviation gasoline types with good anti-detonation properties and low sulfur content | \n\t\t
Catalytic cracking fractions | \n\t\t\t40 - 200 | \n\t\t\t91 – 93 | \n\t\t\tWidely used as a component of high-octane gasoline | \n\t\t
Hydrogenated pyrolysis gasoline | \n\t\t\t60 ÷ 200 | \n\t\t\t96 ÷ 99 | \n\t\t\tUsed in smaller amounts, especially for automotive gasoline | \n\t\t
Polymerization gasoline | \n\t\t\t60 ÷ 200 | \n\t\t\t94 ÷ 96 | \n\t\t\tLess important, high-octane component of gasoline | \n\t\t
Isooctane (2,2,4-trimethylpentane) | \n\t\t\t111 | \n\t\t\t100 | \n\t\t\tHigh-octane component of aviation fuels | \n\t\t
Various alkylates | \n\t\t\t40 ÷ 150 | \n\t\t\t93 ÷ 96 | \n\t\t\tWidely used in blends of aviation gasoline (usually), and automotive gasoline (less frequently) | \n\t\t
Various isomerisates | \n\t\t\t40 ÷ 70 | \n\t\t\t82 ÷ 85 | \n\t\t\tDesirable as components of gasoline types for high-duty applications | \n\t\t
Additives | \n\t\t\t- | \n\t\t\t- | \n\t\t\tComponent which improves lubrication and resistance to detonation combustion, depending on its essential composition | \n\t\t
Characteristics of gasoline components
The quality or properties of fuels affect a number of processes, connected with their use in a wide sense. The impact of the most significant qualitative parameters of fuels for spark-ignition engines on the various performance processes has been established in a number of tests. The criteria are shown in Table 2.
\n\t\t\t\tRequirements relating to gasoline\n\t\t\t | \n\t\t||||
\n\t\t\t\tProperties of fuels\n\t\t\t | \n\t\t\t\n\t\t\t\tStorage,\n\t\t\t\t \n\t\t\t\tdistribution, fuelling\n\t\t\t | \n\t\t\t\n\t\t\t\tFormation of fuel-air mixture\n\t\t\t | \n\t\t\t\n\t\t\t\tOptimum combustion\n\t\t\t | \n\t\t\t\n\t\t\t\tEnvironmental impact\n\t\t\t | \n\t\t
Density | \n\t\t\tChemical composition | \n\t\t\tChemical composition | \n\t\t\tFormation of toxic components of emissions | \n\t\t|
Chemical stability | \n\t\t\tFractional composition | \n\t\t\tFractional composition | \n\t\t||
Corrosive effect | \n\t\t\tVapor pressure | \n\t\t\tCalorific value | \n\t\t||
Level of contamination | \n\t\t\tHeat of evaporation | \n\t\t\tResistance to detonation combustion | \n\t\t||
Low-temperature properties | \n\t\t\tWashing properties | \n\t\t\tBiodegradability | \n\t\t||
Electrostatic properties | \n\t\t\tDensity | \n\t\t|||
Fire safety | \n\t\t\tViscosity | \n\t\t
Qualitative criteria of gasoline in their performance processes
Diesel fuels are made by blending fractions having boiling ranges from 190°C to 350°C, obtained from petroleum processing in the following technologies:
an oil fraction from atmospheric distillation (base fraction) of which the properties depend on the chemical nature of petroleum;
an oil component obtained by thermal cracking; it has a low cetane number, low stability, and a considerable content of unsaturated hydrocarbons;
an oil component obtained by catalytic cracking, which has a rather low cetane number (CN=40…60) because of a content of aromatic hydrocarbons;
an oil component obtained by hydrocracking, used for reducing the corrosive effect of diesel fuels by decomposing sulfur compounds in the process; the amount of the hydrocracking product component which is present in the finished diesel fuel determines the oil category in respect of its content of sulfur links;
an oil component obtained by dewaxing; it deteriorates spontaneous-ignition properties of oils while much improving their low-temperature properties;
a light oil fraction obtained by vacuum distillation (depending on the grade of petroleum being processed) which increases the amount of oil product thus reducing its volatility and increasing its viscosity and density.
Depending on the intended use, diesel fuels are blended essentially in two groups:
diesel fuels for high-speed engines;
diesel fuels for medium-and low-speed engines; another type of blends comprises so-called heating oils which are intended for use in steam boilers for marine or land applications, industrial furnaces (in rolling mills, glass works etc.), firing up coal dust-fired steam boilers, and for technological reasons.
The following improvers can be added to diesel fuels, depending on their intended application:
pro-detonators – to increase the cetane number of diesel fuels;
corrosion inhibitors – to reduce the corrosive effect of diesel fuels and their combustion products;
oxidation inhibitors – to improve diesel fuels in terms of stability, enable longer storage;
depressants – to lower the freezing point of diesel fuels;
additives which reduce the smoke level in exhaust gases by improving the combustion process.
Those fuels for spontaneous-ignition engines (diesel fuels) which have the desirable composition are expected to show the following characteristics:
ensure the correct functioning of the fuel system, especially the injection assembly;
ensure a correct and energy-efficient combustion;
ensure reduction of toxic components and solid emissions;
guarantee chemical stability in the storage process.
The qualitative criteria for diesel fuels which are important for the whole area of their application are shown in Table 3.
\n\t\t\t\tRequirements relating to diesel fuels\n\t\t\t | \n\t\t||||
\n\t\t\t\tProperties of fuels\n\t\t\t | \n\t\t\t\n\t\t\t\tStorage and distribution\n\t\t\t | \n\t\t\t\n\t\t\t\tFunctioning of fuel distribution system\n\t\t\t | \n\t\t\t\n\t\t\t\tAtomization, evaporation, and combustion\n\t\t\t | \n\t\t\t\n\t\t\t\tEnvironmental impact\n\t\t\t | \n\t\t
Density | \n\t\t\tDensity | \n\t\t\tViscosity | \n\t\t\tFormation of toxic components of emissions | \n\t\t|
Chemical stability | \n\t\t\tViscosity | \n\t\t\tSurface tension | \n\t\t||
Low-temperature properties | \n\t\t\tLow-temperature properties | \n\t\t\tSpontaneous ignition properties | \n\t\t\t\n\t\t | |
Corrosive effect | \n\t\t\tLubrication | \n\t\t\tSpontaneous ignition properties | \n\t\t\t\n\t\t | |
Resistance to microbial contamination | \n\t\t\tLevel of solid contaminants and water | \n\t\t\tBiodegradability | \n\t\t||
Electrostatic properties | \n\t\t\tCalorific value | \n\t\t|||
Foaming | \n\t\t||||
Fire safety. | \n\t\t\tWashing properties | \n\t\t
Qualitative criteria of diesel fuels in their performance processes
Regardless of standard fuels, for which applicable standards and approved testing methodologies exist, a number of alternative fuels are known, including biofuels, which can be applied as propulsion materials. Such fuels are used in typical spontaneous-combustion engines, of which the designs are adapted to the properties of conventional (standard) fuels. Therefore, taking into consideration engine requirements, the scope of the respective evaluation criteria ought to correspond to those which apply to conventional fuels. Existing alternative fuels for spontaneous-combustion engines for various applications are listed in Table 4.
\n\t\t\t\tAlternative fuels for use in engines\n\t\t\t | \n\t\t||||
\n\t\t\t\tForm\n\t\t\t | \n\t\t\t\n\t\t\t\tFor spark-ignition engines\n\t\t\t | \n\t\t\t\n\t\t\t\tFor spontaneous-ignition engines\n\t\t\t | \n\t\t\t\n\t\t\t\tFor stationary engines\n\t\t\t | \n\t\t|
\n\t\t\t\tLiquid\n\t\t\t | \n\t\t\tmethanol | \n\t\t|||
ethanol | \n\t\t||||
butanol | \n\t\t||||
other alcohols (tert-butyl TBA, \n\t\t\t\tsec-butyl SBA, isopropyl IPA, neopentyl-NPA); | \n\t\t\tfatty acid esters (FAME, FAEE) from transesterification of rapeseed, soy, sunflower oils | \n\t\t|||
ethers (ethyl-tert-amyl TAEE, ethyl-tert-butyl ETBE, methyl-tert-amyl TAME, methyl-tert-butyl MTBE, diisopropyl DIPE); \n\t\t\t | \n\t\t\t\n\t\t\t | tall fuels (TPO-tall pitch oils) obtained by esterification with ethyl / methyl alcohols of tall oils obtained from gums/resins of coniferous trees (side products in sulfate cellulose production processes and low-temperature dry distillation of wood); | \n\t\t||
hydrogen-based synthetic fuels (including BG, FT, HTU processes) | \n\t\t||||
liquefied petroleum gas (LPG) | \n\t\t||||
dimethylofuran (DMF) | \n\t\t\tfuel-water emulsions (aquasols) | \n\t\t|||
pure vegetable oils | \n\t\t||||
liquefied natural gas (LNG) | \n\t\t||||
\n\t\t\t\tGaseous\n\t\t\t | \n\t\t\tcompressed natural gas (CNG) | \n\t\t|||
\n\t\t\t | biomethane from biogas | \n\t\t\tbiogas | \n\t\t||
dimethyl ether (DME) and (contemplated) diethyl ether (DEE); | \n\t\t||||
gaseous fuels from CtG processes | \n\t\t||||
hydrogen | \n\t\t
Alternative fuels for use in engines
In view of the above data, for a rational assessment of the quality of fuels and their usefulness, especially after storage processes, in engine operation it is necessary to chose applicable assessment criteria and methodology, enabling a relatively fast analysis of changes in the parameter values. The choice of such criteria ought to result from the sensitivity of the respective criteria to fuels’ oxidation and contamination, potentially causing the accepted and recognized limiting values to be exceeded both in respect of their measure and weight.
Experience in using engine fuels indicates that their quality may change, mainly in storage and distribution processes. This causes the necessity to establish the scope and frequency of the quality surveillance of fuels. Some of the generally adopted types, scopes, and frequencies of control of the quality of fuels in their distribution chain are shown in Table 5.
\n\t\t\t\tFuel type and scope of control\n\t\t\t | \n\t\t\t\n\t\t\t\tFuel distribution step\n\t\t\t | \n\t\t
\n\t\t\t\tFull – comprising assessment of the values of all quality parameters of fuels, as described in the standard ON-EN 228 for gasoline and PN-EN 590 for diesel fuels | \n\t\t\t• Refinery – before delivering a fuel lot for distribution; • Storage facilities – after acceptance of fuel for storage and on its release, or periodically, every 6 months of storage | \n\t\t
\n\t\t\t\tControl – comprising assessment of selected parameters, usually appearance, density, fractional composition, and vapor pressure – for gasoline, or flash point and cold filter plugging point – for diesel fuels. | \n\t\t\t• Storage facilities – periodically, during storage; • Fuel station – random analysis, for instance every 3 to 4 deliveries, after acceptance of fuel for storage. | \n\t\t
\n\t\t\t\tShort – comprising determination of density, fractional composition, content of water and contaminants – for diesel fuels, or appearance, color, density – for gasoline. | \n\t\t\t• Fuel station – before acceptance of fuel for storage; • Storage facilities – before unloading tankers. | \n\t\t
Fuel types and scopes of analysis in the distribution chain
The growing demand on liquid fuels necessitates maximization of production output, especially those fuel components which originate from destructive processing. Even though in straight-run processing of petroleum, processes may be conducted which are intended to expand the limits of fractions of base gasoline, kerosine and diesel fuels fractions, yet the main focus is on secondary processing, providing increased numbers and amounts of components of diesel fuels, also by means of thermal and thermocatalytic processes, in the presence or absence of hydrogen.
Owing to the growing number of spontaneous-ignition engines in Europe, the supply of diesel fuels is insufficient while that of gasoline is excessive. As a result, technological processes are carried out which provide the maximum yield of propellant cuts and the residues are processed to provide components which are useful for diesel fuel blending processes.
Experiments were made in which fractions resulting from depolymerization of plastics (KTSF fraction) were “sunk” in petroleum or components which result from re-refining of spent lubricating oils were utilized.
In the production of gasoline, if correct process conditions are maintained, components obtained in isomerization processes, catalytic reforming, full hydrocracking, alkylation (using isobutane) and fluidized-bed cracking (FBCC) are not expected to affect the stability of gasoline during long-term storage.
As regards the motors spirits manufacturing and blending technologies, the following fractions, which originate from the processes of technology discussed above, may very much reduce the duration of safe storage of such fuels:
the gasoline fraction obtained by thermal cracking of the vacuum column residue, which was not hydrogenated;
alternately, the non-hydrogenated fraction of pyrolysis gasoline;
fractions from synthesis of gaseous hydrocarbons;
ethanol as a biocomponent.
The contemporary diesel fuel blending techniques are typically based on the combining of components derived from the following major process unit:
distillation in a tube-tower distillation system
hydrocracking;
fluidized-bed cracking (FBCC);
hydrodesulfurization of soft asphalt;
thermal processing of residue.
The stability of diesel fuels can be much affected by the following factors:
components from thermal processes;
biocomponents (FAAE);
components from WtL processes (KTSF fraction) and re-refining products of the processing of spent lubricant oils.
Some refineries offer co-hydrogenation of petroleum fractions and vegetable oils. The solution carries a potential risk to the blend stability because the process mechanism, connected with the presence in such oils of heterogenic compounds, is not very well known.
Generally, the stability of fuel blends is the lower, the more unsaturated bonds such as those in alkenes (or olefins) they contain.
MicroRNAs (miRNAs) are a small, non-coding, single-stranded RNA consisting of around 22 nucleotides [1]. More than 3% of the human genome (gene portion) encodes for microRNA, and their number is around 1000 [2, 3, 4]. This small RNA can regulate gene expression posttranscriptionally [5, 6, 7]. This small RNA can regulate gene expression posttranscriptionally by binding to its cognate RNA target at the 30 untranslated region (UTR) [8, 9, 10, 11]. A small microRNA was discovered for the first time in C. elegans and is encoded by the Lin-4 gene [12] providing evidence for its evolutionary conservation. This conserved microRNA was found to be involved in many important biological processes including cell proliferation, growth, apoptosis, etc. [13, 14], and many cell-based factors have been known to regulate its expression [15]. The genes transcribing the miRNA are considered to belong to the set of tumor suppressor genes, and the serum level of miRNA can be detected [16, 17]. There are certain miRNAs that can behave as either oncomiRs (whose expression can cause the cancer) or tumor suppressor depending on the context “Several miRNAs cannot be clearly and unequivocally categorized as tumor suppressors or oncomiRs because data in our hands are quite intricate and conflicting since they could act as tumor suppressors in one scenario or as oncomiRs in the other” [18].
Synthesis of miRNA takes place in the nucleus as well as in the cytoplasm. Genes encoding miRNAs are present in the form of a cluster and contain introns (Figure 1). These genes are transcribed by polymerase II with the generation of the primary precursor pri-miRNA. This precursor miRNA consists of a 3′ poly-A tail and a 5′ end cap [19, 20] with a stem-loop structure. RNase 3 Drosha cleaves this structure with the help of its Pasha cofactor DGCR8. This resultant cleaved, precursor structure is known as pre-miRNA and consists of ∼70–90 nucleotides [21]. This ∼70 nt precursor is exported to the cytoplasm by Exportin-5.
Biogenesis of microRNA.
In the cytoplasm, the whole pri-miRNA is recruited by a RNA-induced silencing complex (RISC) and is converted into mature miRNA. These are mediated by an RISC leaching complex (RLS), which is basically a multiprotein complex and consists of a double-stranded RNA domain protein (DICER), tar RNA-binding protein (TARB), and the Ago 2 protein. The RNAse 3 DICER along with its cofactor yields duplex miRNA (19–25 nucleotide duplex miRNA with 2 nucleotide overhangs at each 3′end). During the process of cleavage, two strands are formed, namely, a functional and a passenger strand. The functional strand along with the Ago protein (RISC) is involved in gene silencing function, while the passenger strand is degraded due to its instability. This miRISC incorporates one strand of miRNA (functional strand and guide strand) so that it takes the guidance from this complex to target mRNA (complementary) for its degradation or inhibition at the translational level [22]. miRNA is processed in the cytosol and transported to the blood. It is resistant to degradation because it is carried by complexes of lipoprotein inclusions [23] or in the form of exosomes [24, 25].
The mechanism of action of microRNA is such that it binds to its partial complementary sequence in the target mRNA (that codes for protein). Hence, the expression is repressed (Figure 2) and no product is synthesized [7].
Mechanism of action of miRNA.
In another scenario, the microRNA may bind to the complementary sequence of target mRNA that codes for protein and initiates RNA-mediated gene silencing, with the resultant cleavage of the target RNA (Figure 3) [26].
Mechanism of miRNA.
There are reported differences in the expression pattern of miRNA in normal and cancer cells [27]. Some miRNAs are overexpressed, while the others are downregulated in different kinds of cancers [28]. Due to its small size and resistance to RNase-mediated degradation, they have the potential as powerful biomarkers for cancer diagnosis [29]. miRNA expression is involved with the rearrangement of chromosomes, methylation of the promoter region, and transcriptional regulation. miRNA-mediated aberrations in one or more of these processes can culminate in alterations in protein and mRNA expression [30].
Different miRNAs are involved in different types of cancers:
Breast cancer is the most prevalent form of cancer in women. Among 12.7 million cancer cases globally, breast cancer is most frequently diagnosed, that is, 23 and 14% deaths due to breast cancer have been reported [1, 31]. The alarmingly increasing mortality data coupled with increases in relapses warrants an improved molecular understanding of the etiology and mechanistic details that contribute to the chemoresistance. There are four subtypes (intrinsic) of breast cancer. These are ErbB2+ (epidermal growth factor receptor 2-positive (also called HER2)), luminal A (hormone receptor positive for estrogen and progesterone, HER2), luminal B (hormone receptor positive for estrogen and progesterone and positive or negative for HER2), and basal like (hormone receptors negative for estrogen, progesterone, and HER2) showing its heterogeneity. Many of the microRNAs play a role in the inhibition of breast cancer. The upregulation of miR-21 (Table 1) results in the increased expression of BCL-2 protein and chemoresistance in breast cancer [38]. MiR-125b shows the resistance to chemotherapeutic agents 5-fluorouracil, and it has higher expression in the patients that are nonresponsive to this agent (Table 2). Many promote the prognosis of breast cancer by targeting the tumor suppressor at the gene level and activating the transcriptional factors that are oncogenic in nature [32, 38].
Sr. no. | MicroRNAs | Potential targets | Function | Ref. |
---|---|---|---|---|
1 | miR-10b | Homeobox D10 | Promotes cellular invasion, migration, and metastasis by targeting the RhoC | [32] |
2 | miR-21 | Programmed cell death protein 4, hypoxia-inducible factor-1α | Promotes cellular invasion, metastasis, epithelial-to-mesenchymal transition and migration | |
Phosphatase and tensin homolog, programmed cell death protein 4, tropomyosin 1 | Promotes cellular invasion | [33] | ||
Metalloproteinase inhibitor 3 | Promotes cellular invasion | [34] | ||
3 | miR-155 (chemosensitive determinant by targeting the FOXO3) | Suppressor of cytokine signaling 1 | Promotes cell proliferation and growth | [35] |
Tumor protein p53 inducible nuclear protein | Promotes cell proliferation | [36] | ||
Forkhead box protein O3 | Promotes cell proliferation and cell survival | [37, 38] | ||
4 | miR-373 | CD44 (inversely correlated) | Promotes cellular invasion and migration | [39] |
Promotes cellular invasion and metastasis | [40] | |||
5 | miR-520c | Promotes cellular migration, invasion, and metastasis | [39] |
MicroRNAs upregulating the breast cancer.
Meta-analysis or Cochrane reviews documenting the involvement of a specific miRNA or a battery of miRNAs contributing to relapse or recurrence can be displayed as a separate table for each of the cancers.
Sr. no. | MicroRNAs | Potential targets | Function | Ref. |
---|---|---|---|---|
1 | miR-125b | Erythropoietin, erythropoietin receptors (positive correlation with ERBB2/HER2 expression) | Inhibition of cellular differentiation and proliferation | [41] |
Glutamyl aminopeptidase or aminopeptidase A, casein kinase 2-alpha, cyclin J, multiple EGF-like domains 9 | Inhibition of cellular proliferation | [42] | ||
Receptor tyrosine-protein kinase erbB-2 (human epidermal growth factor receptor 2) (induction of miR cause the downregulation of ERBB2/ERBB3) | Inhibition of invasion and migration | [43, 44] | ||
2 | miR-205 | High-mobility group box 3 gene | Suppression of invasion and proliferation | [45, 46] |
3 | miR-17-92 | Mitogen-activated protein kinase kinase kinase 2 | Promotes the antitumoral activity of natural killer cells and reduction in metastasis | [47] |
4 | miR-206 | Cyclin D2, connexin 43 | Reduction in invasion, migration, and metastasis | [48] |
5 | miR-200 | Zinc finger E-box binding homeobox 1/2, snail family zinc finger ½ | Reduction in tumor growth, EMT through E-cadherin, and metastasis | [49] |
6 | miR-146b | Nuclear factor kappa B, signal transducer, and activator of transcription 3 | Reduction in survival and metastasis via interleukin 6 | [50] |
7 | miR-126 | Insulin-like growth factor-binding protein 2, c-Mer tyrosine kinase, phosphatidylinositol transfer protein, cytoplasmic 1 | Reduction in angiogenesis and metastasis | [51] |
8 | miR-335 | SRY-related HMG-box 4, tenascin C | Suppression in migration and metastasis | [52] |
9 | miR-31 | Ras homolog gene family | Targets various steps of metastasis and invasion for inhibition | [38] |
WAS protein family, member 3, Ras homolog gene family | Reduction in the metastasis and progression of cancer | [53] | ||
WAS protein family, member 3 | Reduction in the metastasis and progression of cancer | [54] |
MicroRNAs downregulating the breast cancer.
The Rab protein is a member of the Ras superfamily (Figure 4). This protein is a G-protein-coupled receptor and is involved in many cellular processes including fusion, budding, synthesis of vesicles, and motility [55]. A member of the Rab class is Rab11a, and this protein has many functions including cellular migration and phagocytosis [56]. In breast cancer there is overexpression of Rab11a protein [57] and is regulated by miRNA 320a. This miRNA can downregulate Rab11a protein, thereby mediating the inhibition of breast cancer progression.
MicroRNA and breast cancer.
MiR-320a has an important role in tumor suppression [58] and can be a biomarker for breast cancer. This miR-320a results in a 15% increase of cells in G0/G1, and the population of cells in the S phase is decreased. Apart from the G0/G1 cell cycle arrest, miR-320a also increases the activity of caspase resulting in the induction of apoptosis [59]. The potential target of miR-20 is Rab11a; it has two binding sites at the 3′UTR region for miR-320a and can mediate its posttranscriptional repression. This protein is also necessary for the activation of Akt via phosphatidylinositol-4-kinase (PI4K3) in breast cancer—a pro-survival signal [60]. Further, overexpression of Rab11a protein results in the reversal of cell cycle arrest and apoptosis mediated by miR-320a by targeting the MTDH at 3′UTR [61]. The gene coding for the Rab coupling protein (RCP) (a Rab11-FIP1C (Rab coupling protein)) is amplified in breast cancer and aids in the sorting of epidermal growth factor receptor (EGFR) [62, 63]. For the metastasis or migration of cancer, the cell critical factor is RCP which mediates this effect via cell surface integrin alpha-5-beta-1 demonstrating that Rab11a is a protein that is involved in the metastatic or invasive phenotype of breast cancer [64, 65].
Colorectal cancer is the third most common cancer around the world. The incidence rate is increased up to 6% [66]. Survival rate can increase to 90%, if it is diagnosed at an early stage. Survival rate is inversely proportional to the stage of cancer [67].
In a study, the cluster of miR-17/miR-92 (chromosomal region 13q31.1 with miR-20a as one of its members). The region encompassing this cluster is under the regulation of the oncogenic Myc transcriptional factor and TGF-β [68, 69]. Overexpression converts a benign tumor to colorectal cancer [70].
MicroRNA and colorectal cancer.
Mir-20 acts as a potential colorectal cancer cell biomarker [71]. Induction of miR-20-mediated EMT is a critical factor contributing to the increases in tumor cell migration, metastasis, E-cadherin downregulation, and upregulation of matrix metalloproteinases (Figure 5) [72, 73]. This microRNA can cause a delay in TGF-β-mediated G1/S transition. However, cell cycle progression occurs due to an inactivating mutation in this pathway [74]. Normal TGF-β-mediated signaling can be a cytostatic response and inhibit tumorigenicity in colorectal cancer cells [75]. miR-20 may be degraded by a bacterial strain that is dominant in the lumen of the bowel of colorectal patients. Hence, expression of miR-20a is reduced in patients having colorectal adenoma [76, 77, 78].
In another study, miR-34a modulates EMT and MET processes. There is methylation in CpG islands (cancer specific), and these are repressed by IL-6/STAT3 pathway which is mediated by interleukin-6 receptors (IL6R) and inactivation of TP53. This results in downregulation of miR-34a [79]. miR-34a inhibits SIRT and activates TP53. A positive feedback loop has been suggested between miR-34a (Table 3) and TP53 [81]. In many cancers, TP53-inducible microRNA is miR-34a [82].
Sr. no. | MicroRNAs | Potential target | Function |
---|---|---|---|
1 | miR-185 | Ras homolog gene family, member A, and cell division control protein 42 homolog | Reduction in the proliferation, induction of cell cycle arrest at the G1 stage, and promotion of apoptosis |
2 | miR-192 | cyclin-dependent kinase inhibitor 1 | Regulating the p53 |
3 | miR-215 | ||
4 | miR-34a | Tumor suppressor p53 | Modulate the EMT transition |
MicroRNAs suppressing the colorectal cancer [80].
In another study, miR-200 is downregulated in primary colorectal cancer (invasive stage) correlatable with the disruption of the basement membrane [83]. The miR-200 family consists of five members and is encoded in two clusters. One cluster is present on chromosome 1 and encodes for miR-200a, miR-200b, miR-200c, and miR-141. The other cluster is present on chromosome 12 and encodes for miR-141. The potential target of miR-200 family is ZEB1/ZEB2 which is a repressor of CDH1 (Table 4). Expression of all members of this family can be repressed following methylation of CpG islands in the regulatory region of their genes [84, 85]. Strong expression of miR-200 results in metastatic colorectal cancer [83]. Another study shows that miR-155 and miR-21 are overexpressed in colorectal cancer [86]. In another study involving colorectal cancer patients, the expression of miR-195 and miR-497 is reduced [87].
Sr. no. | MicroRNAs | Potential target | Function |
---|---|---|---|
1 | miR-130a | Mothers against decapentaplegic homolog 4 (SMAD4) | Enhances the cell proliferation and migration |
2 | miR-301a | ||
3 | miR-454 | ||
4 | miR-200 | Zinc finger E-box-binding homeobox ½ | Promotes metastasis |
MicroRNAs promoting the colorectal cancer [80].
Cervical cancer is the most common cause of death among women in the developing countries [88, 89]. Cervical cancer can cause the death of 270,000 women per year [90]. Human papillomavirus (HPV) is the causative agent, with the E6 and E7 proteins targeting p53 and pRb, respectively [91].
Several miRNAs are upregulated and downregulated during cervical cancer (Table 5). miR-135b is a biomarker for cervical cancer. Suppression of this biomarker results in the inhibition of cell growth.
Type of miRNA | Function | Ref. |
---|---|---|
miR-491-5p | Downregulated; suppress cervical cancer by telomerase reverse transcriptase and regulate the PI3K/AKT pathway | [92] |
miR-142-3p | Inhibit the proliferation of cell Frizzled_7 receptor (FZD7) | [93] |
miR-142-3p | Inhibit the growth of cell via downregulation of its FOXM1 target | [94] |
AmiRNA involved in cervical cancer.
Downregulation of miR-135b results in the percentage of G1 cells with a concomitant decrease in those in the S phase. The expression of cyclin-dependent kinases (p27 and p21) is increased and that of cyclin D1 is decreased. Cyclin D1 (nuclear protein) is responsible for the regulation of cells (proliferating) that are at the G1 phase of the cell cycle [72, 73].
There seems to be an inverse relationship between miR-135b and FOXO1 protein. When FOXO1 protein is downregulated, cervical cancer is promoted. When FOXO1 protein is expressed, then there is an increase in the p27 and p21 expression with a decrease in cyclin D1 level and cell cycle is arrested [95, 96]. So, when miR-135 is downregulated, FOXO1 is upregulated with the resultant inhibition of cell growth (Figure 6).
MicroRNA and cervical cancer.
In cervical cancer, miR-196a is upregulated and its targets are p27Kip and FOXO1. It promotes the transition of cells from G1 phase to S phase, enhances the cellular proliferation by involving the PI3K/Akt pathway, and is involved in tumorigenesis [97].
In one study, miR-10a is overexpressed in cervical cancer (Long et al., 2012; [28]). The target of miR-10a is transmembrane protein type 1 close homolog of L1 (CHL1) that is downregulated. A decrease in CHL1 protein dysregulates PAK and MAPK pathways resulting in increases in cell growth followed by migration and invasion [98].
In another study, miR-21 is upregulated in cervical cancer, and it is located at the 17q23.21 locus (Table 6). The pri-miR-21 is transcribed by the intronic region of TMEM49 (protein-coding gene). This miRNA targets the p53 and Cdc25 (regulators of the expression of genes), TPM1 and RECK (suppressing the metastasis), and PTEN and PDCD4 (inducing the apoptosis of metastasized cell). Hence, decreases in this miRNA can result in the PDCD4 gene providing signals for the activation of the RAS pathway. This activation, in turn, activates the transcription factor AP-1gene. This AP-1 binds to a specific site on the promoter of miR-21 and as a result miR-21 gene is transcribed [99], thereby providing a plausible mechanism for a positive feedback loop.
Sr. no. | MicroRNAs | Potential targets | Function | Ref. |
---|---|---|---|---|
1 | miR-196a | Binds to the 3′UTR of p27Kip and FOXO1 and inhibits their translation | Increases in cell proliferation and tumorigenesis | [97] |
2 | miR-10a | Has an inverse relation with the expression of close homolog of L1 (CHL1) transmembrane protein type 1—a cell-adhesion protein | Cell growth followed by migration and invasion | [91] |
3 | miR-21 | Negatively regulates p53 and Cdc25, TPM1 and RECK, and PTEN and PDCD4 | Enhances the expression of genes associated with cell proliferation, metastasis, as well as those involved in the antiapoptosis effect | [91] |
4 | miR-886-5p | Negatively regulates the Bax gene | Dysregulation of the gene involved in apoptosis (miR-10a, miR-106b, miR-21, miR-135b, miR-141, miR146, miR-148a, miR-214, and miR-886-5p) | [91] |
5 | miR-20a | TNKS2 oncogene is upregulated (by binding at 3′UTR of mRNA of TNKS2 results in enhanced translation) | Migration, colony formation, and invasion | [91] |
MicroRNAs activating the cervical cancer.
It was reported that miR-886-5p targets and negatively regulates Bax gene expression via inhibition of translation, and hence, this form of control may be significant for the development of cervical cancer. When there is a death signal, the proapoptotic protein coded by Bax gene is inserted into the outer membrane of mitochondria. As a result, cytochrome C is released, and the initiator caspase-9 is subsequently activated with the initiation of apoptosis (Table 7) [91].
Sr. no. | MicroRNAs | Potential target | Function |
---|---|---|---|
1 | miR-143 | Target k-Ras, Bcl-2 and Macc1, specifically downregulation of Bcl-2 | Inhibition of apoptosis and uncontrolled cell proliferation |
2 | miR-129-5p | Downregulates HPV18 E5 and E7 expression as well as inhibits the translation of SP-1 transcriptional factor | Suppressing the progression of cervical cancer |
3 | miR-34a | Cyclin E2 and D1, CDK6, E2F3, CDK4, E2F1, E2F5, P18, Bcl-2, and SIRT1 | Aberrations in cell proliferation and differentiation—cell transformation |
MicroRNAs suppressing cervical cancer [91].
Liver cancer is rising very rapidly globally with aflatoxins also contributing to its etiology. Specific miRNA may be expressed in the case of liver cancer. One of the miRNA biomarkers in liver cancer is miR-26a. Its expression is reduced in liver cancer unlike normal hepatic cells, where its expression level is increased [100].
MicroRNA and liver cancer.
miR-26a and miR-34a cause an increased number of cells in the G1 phase of the cell cycle, while there is a decrease in the cells in the S phase of the cell cycle. miR-26 causes cell cycle arrest at the G1 phase [84]. In the 3′UTR region of cyclins E2 and D2, there is a conserved binding site for miR-26a. miR-26a binds to these binding sites and represses the expression of both cyclins (Figure 7). miR-26 causes the induction of apoptosis in the tumor cells and suppresses hepatic cancer [101].
Kim et al. studied the expression of miR-31 in liver cancer (Table 8). The main target of miR-31 is CDK2 protein and HDAC2, with these proteins suppressed in the livers of normal individuals. There is an enhanced expression of CDK2 protein and HDAC2 in liver cancer. When HDAC2 is suppressed, p21WAF1/Cip1 and p16INK4A are activated, and positive regulators of the cell cycle (cyclin D1, CDK2, and CDK4) are suppressed simultaneously [102].
Sr. no. | MicroRNAs | Potential targets | Function | Ref. |
---|---|---|---|---|
1 | miR-26a | Cyclin E2 and D2 | The arrest of the cell cycle at G1 phase | [84] |
2 | miR-31 | CDK2 protein and HDAC2 | Suppress the positive regulators of cell cycle and promote those proteins involved in EMT-related processes | [102] |
MicroRNAs suppressing the liver cancer.
In another study, the expression of miR-9 enhances the formation of tumor spheres in the liver. The direct target of the miR-9 is PPARA and CDH1 genes and regulates them via binding to the 3′UTR region of these genes. Upregulation of miR-9 enhances the level of vimentin (mesenchymal marker) and deregulates the CDH1 (Table 9). The transcriptional factor PPARA has been implicated in the metabolic homeostasis of the liver by regulating the nuclear factor-4 alpha (hepatocyte HNF4A) gene, which is a tumor suppressor. In liver cancer, miR-9 suppresses the CDH1 and also suppresses the PPARA at their mRNA level by binding to the 3′UTR of these genes [103].
Sr. no. | MicroRNAs | Potential targets | Function | Ref. |
---|---|---|---|---|
1 | miR-9 | Influences the PPARA/CDH1pathway | Suppress the tumor suppressor | [103] |
2 | miR-525-3p | Downregulates ZNF395 | Enhances cell growth and prevent apoptosis | [104] |
MicroRNAs activating the liver cancer.
In one study, there is overexpression of miR-525-3p in liver cancer, and its potential target is a zinc finger protein (Krüppel C2H2 type family) ZNF395. This zinc finger protein was originally a transcriptional factor and binds to the promoter region of the human papillomavirus (HPV). This protein mediates the regulation of PI3K/Akt pathway and causes the inhibition of cell growth via the induction of caspase-3 and the promotion of apoptosis. The expression of miR-525-3p enhances cell growth and prevention of apoptosis [104].
In countries in the West, prostate cancer is a more prevalent form of cancer among males with an increasing incidence rate [105]. Prostate cancer is the result of undesirable genomic alteration [106, 107]. CD9 is inactivated during prostate cancer and may cause its progression [108].
In the prostate cancer, serum level of miR-141 is elevated [109]. So it acts as the biomarker of prostate cancer. In the progression or repression of prostate cancer, miR-141 function is understood poorly [110]. One other study is done by Waltering et al. in which miR-141 is castrated and results in upregulation and activation (Figure 8). This causes the LNCaP cell growth to increase. This miRNA is also involved in the regulation of signaling of the androgen. This androgen has a crucial role in the growth of prostate cancer (castration-resistant and androgen-dependent). So it may be involved in the progression of prostate cancer [111, 112].
miRNA and prostate cancer.
In a study involving prostate cancer, miR-888 was found to be upregulated. Its target is the tumor suppressors SMAD4 and RBL1. Binding of this miRNA to the 3′UTR causes their downregulation. RBL1 is the member of the RB (retinoblastoma) family and blocks the progression of cells at the G1-S phase following its binding and inhibition of the transcription factor E2F. SMAD4 protein binds to SMAD receptors and transduces the signal initiated by TGF-β/BMP ligands in order to regulate differentiation and cell growth [113].
In another study, there is the downregulation of miR-23a, b (Table 10). There is upregulation of the-Myc gene which causes the repression of these miRNAs at the transcriptional level. Mitochondrial glutaminase protein is expressed in the prostate cancer cells. Consequently, glutamine catabolism is increased, providing a growth advantage to the cancer cells [114].
Sr. no. | MicroRNAs | Potential targets | Function | Ref. |
---|---|---|---|---|
1 | miR-141 | LNCaP cells | Promote cell growth Decreased growth in response to anti-miR-141 treatment | [112] |
2 | miR-888 | Downregulates SMAD4 and RBL1 | G1-S phase transition | [113] |
MicroRNAs activating the prostate cancer.
In another study, miR-34a is suppressed in prostate cancer. The target of miR-34a is deacetylase sirtuin (SIRT1) and cyclin-dependent kinase 6 (CDK6). CDK6 regulates cyclin D, which, in turn, regulates cell cycle progression and G1-S phase transition, while p53 protein-dependent apoptosis is regulated by SIRT1 via deacetylation and stabilization of p53. The target of the p53 gene is miR-34a. It is suggested that there is a positive feedback loop in which SIRT1 mediates the activation of miR-34a via stabilization of p53 and induces the apoptosis and blocks the cell cycle transition. This activation of p53 causes the upregulation of miR-34a which in turn suppresses the SIRT1 (Table 11) [114].
Sr. no. | MicroRNAs | Potential targets | Function |
---|---|---|---|
1 | miR-23a,b | Glutaminase protein (indirect) | Glutamine catabolism |
2 | miR-34a | SIRT1 and CDK6 | Progression of cell cycle, G1-S phase transition, and antiapoptosis |
MicroRNAs suppressing the prostate cancer [114].
The leading cause of death around the world is lung cancer by tobacco smoke. This environmental lifestyle-related factor may cause undesirable epigenetic and genetic modifications [115]. The key role in lung cancer is the alteration and mutation in tumor suppressor genes (p53 and RB/p16pathway) and less frequent is the genetic alteration of FHIT, K-ras, MYO18B, and PTEN [116].
Five miRNAs were differentially expressed in lung cancer tissues, and these include miR-21, miR-155, miR-145, miR-17-3p, and hsa-let-7a-2. Specifically, hsa-miR-155 levels were increased, while that of hsa-let-7a-2 was downregulated [117].
There is a functional interaction of let-7 with the Ras as a target gene is overexpressed associated with protein kinase and resulting intracellular pathway of signaling [118]. The molecular mechanism is unclear involving miRNA in lung cancer. Alteration in the somatic genes resulted in the defective miRNA expression in lung cancer. This reduced expression of miRNA (has-let-7a-2) in the lung cancer is due to epigenetic modification and results in the silencing of tumor suppressor gene and many others (Figure 9) [119, 120]. The expression of hsa-miR-21 is upregulated in cancer cell and causes the inhibition of product of gene which initiates apoptosis and causes lung cancer [121]. In a report miR-17∼92 cluster is overexpressed in the lung cancer. This cluster consists of six miRNAs.
miRNA and lung cancer.
This cluster in lung cancer is transactivated via MYC and members of the E2F family. The direct target of this cluster is HIF-1α. Upregulation of MYC causes the downregulation of HIF-1α and affects proliferation of cell in normoxia without affecting the hypoxic condition. Overexpression of this cluster causes knockdown of retinoblastoma gene and results in the formation of reactive oxygen species. Another direct target of this cluster is RAS-related protein 14 (RAB-14), and it is downregulated by this cluster and results in the initiation and development of cancer [122].
In another study, miR-21 is upregulated in the lung cancer. Its direct target is tumor suppressor gene PTEN that is repressed by overexpression of miR-21 (Table 12), which results in cell growth enhancement and non-small cell lung carcinoma invasion [123]. miR-21 is upregulated by RAS via PI3K and RAF/MAPK pathways [122].
Sr. no. | MicroRNAs | Potential targets | Function | Ref. |
---|---|---|---|---|
1 | let-7 | Ras | Protein kinase-associated signaling pathway | [118] |
2 | miR-17∼92 | HIF-1α and RAB14 | ROS and initiation and development of cancer | [122] |
3 | miR-21 | PTEN | Cell growth enhancement and invasion | [122] |
MicroRNAs activating the lung cancer.
In another study, miR-34 is downregulated in the lung cancer. This miRNA is directly regulated by p53 and regulates the apoptosis and arrest of the cell cycle in cancer [81].
The miR-34/miR-499 is downregulated in lung cancer and its direct target is E2F and p53 (Table 13). Both miRNAs suppress the E2F and upregulate the p53 via SIRT1 so cell growth is increased [124].
Sr. no. | MicroRNAs | Potential targets | Function | Ref. |
---|---|---|---|---|
1 | miR-34 | p53 | Regulate the apoptosis and arrest of cell cycle | [81] |
2 | miR-34/miR-499 | E2F and p53 | Cell growth and proliferation | [124] |
3 | miR-15/miR-16 | Cyclin D1 | The arrest of the cell cycle at the G1 phase | [122] |
MicroRNAs suppressing the lung cancer.
The miR-15/miR-16 is downregulated in lung cancer. There is upregulation of cyclin D1 with the downregulation of miR-15/miR-16. The overexpression of miR-15/miR-16 causes the arrest of the cell cycle at G1 phase [122]
The second malignancy that is widely prevailed is the gastric cancer which results in 12% deaths around the world [125]. Gastric cancer is the result of a series of steps. When transforming growth factor (TGF-beta) resistance is developed and E2F1 is upregulated, then gastric cancer is developed [126, 127].
In gastric cancer, there is upregulation of cluster of miR-106b-25 present on Mcm gene [128]. The transition of the G1/S phase of the cell cycle is targeted by Mcm gene. It ensures that DNA is replicated only one time when replication fork is assembled on the DNA during each cycle [129]. When cells exit from the mitosis, then expression of cluster of miR-106b-25 is activated by E2F1 (Figure 10) and gains the reentry in the G1 phase of the cell cycle. The cell cycle inhibitor is p21 [130].
miR-106b-25 cluster.
The cytokine TGF-beta causes the cell cycle arrests by activating p21 and causes the apoptosis [131]. As this cytokine is activated it causes the downregulation of miR-106b-25 cluster, reduces the expression of E2F1, causes the cell cycle arrest at G1/S phase of cell cycle, and causes the induction of apoptosis. The key target of miR-93 and miR-106b is E2F1 [132]. The key target of miR-25, the biomarker of gastric cancer, is TGF-beta cytokine [133]. The target of cytokine in mediating the apoptosis is Bim protein that in turn causes the activation of proapoptotic Bax and Bad molecules acting as an antagonist of Bcl2 and BclXL antiapoptotic factors (Figure 11) [134].
miRNA and gastric cancer.
Lim found that miR-196b is upregulated in the gastric cancer (Table 14). This miRNA is present in chromosome 9 at HOXA cluster. There is a positive association of expression of miR-196b with the expression of HOXA10. Unmethylation of CpG islands results in the expression of miR-196b. The HOXA10 expression results in hematopoietic stem cell proliferation and progenitor cell proliferation leading to the development of cancer via expression of genes that codes for integrin-β3, TGFβ2, and dual-specificity protein phosphatase 4 [135].
Sr. no. | MicroRNAs | Potential targets | Function | Ref. |
---|---|---|---|---|
1 | miR-106b-25 | E2F1 | Antiapoptosis and cell proliferation | [132] |
2 | miR-196b | HOXA10 | Progenitor and hematopoietic stem cell proliferation | [135] |
MicroRNAs activating the gastric cancer.
We studied miR-375 is downregulated in gastric cancer (Table 15). Its expression in cancer cell causes the decrease in cell viability by downregulation of PDK1 and JAK2 revealing that miR-375 is a tumor suppressor in gastric cancer [136, 137].
Sr. no. | MicroRNAs | Potential targets | Function | Ref. |
---|---|---|---|---|
1 | miR-375 | PDK1 and JAK2 | Decrease the cell viability | [136, 137] |
2 | miR-135a | E2F | Suppress cell proliferation, metastasis, and EMT | [138] |
MicroRNAs suppressing the gastric cancer.
In another study, miR-135a is a tumor suppressor in gastric cancer. Upregulation of miR-135a causes the suppression of gastric cancer via suppression of proliferation of cell via E2F, metastasis, and EMT. In gastric cancer, lymph node metastasis is associated with proliferation, metastasis, and EMT which is suppressed by overexpression of miR135a [138].
In males, bladder cancer is an important malignancy present in two forms that are muscle invasive and non-muscle invasive (benign) [139]. There are two microRNAs associated with bladder cancer. They are miR-21 and miR-129 [140].
In the bladder cancer, miR-129 and miR-21 both are upregulated. The direct target of miR-21 is the tumor suppressor genes that are TPM1 and PTEN (Figure 12) [141, 142]. The known targets of miR-129 are the genes involved in the regulation of transcription and processing of miRNA that are TAMTA1 and EIF2CA [143]. The mir-129’s pathway of death effectors leads to the tumor as its target is also SOX4 [144].
miRNA and bladder cancer.
According to one study, miR-19a is frequently upregulated in the bladder cancer. The expression of miR-19a is related to PTEN expression (Table 16). PTEN is a tumor suppressor gene. When miR-19a is overexpressed, it causes the downregulation of PTEN and increases the cell level of phosphatidylinositol-3,4,5-trisphosphate in AKT/PKB pathway. When growth factors are released, then the AKT pathway is initiated and cell growth is increased [145].
Sr. no. | MicroRNAs | Potential targets | Function | Ref. |
---|---|---|---|---|
1 | miR-129 | TAMTA1 and EIF2CA | Regulation of transcription | [143] |
2 | miR-21 | TPM1 and PTEN | Growth of tumor cell | [141] |
3 | miR-19a | PTEN | Increase in the cell growth | [145] |
MicroRNAs activating the bladder cancer.
Zhang studied that miR-125b is downregulated in bladder cancer. The expression of miR-135b causes the inhibition of formation of colony and development of cancer via suppression of E2F3 which is overexpressed in bladder cancer [74].
In another study angiogenesis in the bladder cancer is suppressed by miR-34a (Table 17). The target of miR-34a is CD44 and causes the suppression of CD44 when upregulated which results in the regulation of transcription of the various genes in bladder cancer. Over expression of miR-34a causes the inhibition of invasion, metastasis, migration, tube formation, and angiogenesis by targeting the CD44 [146].
Glioblastoma is the tumor of astrocytes, star-shaped cells that form the supportive tissues (glue-like) of the brain. This is readily metastasizing tumor because it is surrounded by large blood vessels. Glioblastoma is a complex and heterogeneous tumor that comprises on neoplastic cells, endothelial cells, stemlike cells, neural precursor cells, microglia, reactive extracellular components, and peripheral immune cells [147].
The biomarker in glioblastoma is miR-21 that is upregulated in this cancer (Figure 13). It mediates its effect in two ways: acting at the translational level and acting at the transcription level. It binds the 3′UTR region of the target gene (for apoptosis) [148] and causes the inhibition of transcription of apoptotic genes by decreasing the stability. It also resists the caspases 3 and 7 that are important apoptotic agents so apoptosis does not occur [149].
miRNA and glioblastoma.
Upregulation of miR-221 and miR-222 was in glioma cells. These two miRNAs present as a cluster on Xp11.3 and have the same target. Functional studies revealed that there is an association of these two miRNAs with the progression of the cell cycle. Their direct target is cyclin-dependent kinase 1B/p27. The overexpression of these miRNAs cause the activation of quiescent glioblastoma cells and the progression of these cells from G1 phase to S phase of the cell cycle. miR-221/miR-222 also targets the p57 and p27 (inhibitors of cell-dependent kinase) to prevent the quiescence at G1 phase and cause their entry to S phase of the cell cycle. The miR-221/miR-222 also targets the PUMA, a proapoptotic protein, to prevent the apoptosis (Table 18) [150].
Sr. no. | MicroRNAs | Potential targets | Function | Ref. |
---|---|---|---|---|
1 | miR-21 | Caspases 3 and 7 | Antiapoptotic | [149] |
2 | miR-221/miR-222 | Cyclin-dependent kinase 1B/p27 | Prevent the apoptosis | [150] |
MicroRNAs activating the glioblastoma.
Another biomarker miR-128 is found to be downregulated in glioblastoma. The expression of miR-128 causes the regulation of proliferation of glioblastoma multiform (GBM) cells via targeting the PDGFR-α and EGFR, the oncogenic kinases (receptor tyrosine kinases) (Table 19). It suppresses the GBM by enhancing the differentiation of neuronal cells. It also targets the signaling molecules in the PI3-kinase/AKT pathway which causes the tumor cell proliferation [147].
Sr. no. | MicroRNAs | Potential targets | Function | Ref. |
---|---|---|---|---|
1 | miR-128 | PDGFR-α and EGFR | Enhancing the differentiation of neuronal cells | [147] |
2 | miR-7 | EGFR | Reduction of cell viability | [151] |
MicroRNAs suppressing the glioblastoma.
In other study miR-7 is downregulated in glioblastoma. Its target is EGFR and causes the inhibition of AKT pathways and EGFR and results in the reduction of cell viability of GBM via direct binding to mRNA of EGFR or via targeting to IRS1 and IRS2 (insulin receptor substrate). The major regulators EGFR and IRS are at upstream site of AKT pathway [151].
This is the cancer of B lymphocytes (antibodies), and it is a prevalent form of leukemia in the adult around western countries [152].
In B cell leukemia, the expression of three microRNAs is seen as cancer biomarker. These are miR-15a, miR-16-1, and miR-19a (Figure 14). Two microRNAs are present at 13q14.3 chromosomal location; these are miR-15a and 16-1 [153]. The expression of these two is decreased in this leukemia, whereas the expression of miR-19a is increased [152]. The region encoding for miR-15a and miR-16-1 was deleted. This leads to the presence of the genes of IgVH that were mutated [154]. The potent target of miR-19a is PTEN, and there is down-expression of this PTEN gene; hence its protein is not properly synthesized because the promoter of the gene is hypermethylated [155].
miRNA and B cell lymphocytic leukemia.
The miR-16-1 and miR-15a (located on chromosome 13) are downregulated in B cell lymphocytic leukemia (Table 20). These miroRNAs target the p53 gene which is a tumor suppressor gene. When these miRNAs are downregulated, then the expression of p53 is reduced or inhibited, and expression of BCL-2 is increased which prevent the apoptosis and cell survival is increased [156].
Sr. no. | MicroRNAs | Potential targets | Function | Ref. |
---|---|---|---|---|
1 | miR-15a | p53 | Prevent the apoptosis and cell survival is increased | [153] |
2 | miR-16-1 | p53 | Prevent the apoptosis and cell survival is increased | [156] |
MicroRNAs suppressing the B cell lymphocytic leukemia.
In one study, miR-17/miR-92 cluster is overexpressed in the B cell lymphocytic leukemia (Table 21). The direct target of this cluster is PTEN and Bim. The PTEN is a tumor suppressor gene, and Bim is proapoptotic protein. Overexpression of this cluster causes prevention of apoptosis and progression of tumor [157].
Sr. no. | MicroRNAs | Potential targets | Function | Ref. |
---|---|---|---|---|
1 | miR-19a | PTEN | Cause the tumor | [155] |
2 | miR-17/miR-92 | PTEN and Bim | Prevention of apoptosis and progression of tumor | [157] |
3 | miR-155 | SHIP1 | Inhibition of BCR signaling and surface immunoglobulin | [158] |
MicroRNAs activating the B cell lymphocytic leukemia.
In other study, miR-155 is overexpressed in the B cell lymphocytic leukemia [159]. The potential target for miR-155 is SHIP1. Expression of miR-155 causes the alteration of BCR response in signaling pathway via the modulation of SHIP1 expression in chronic lymphocytic leukemia. Scr homology-2 domain comprising the inositol 5-phosphatase is encoded by SHIP1. This phosphatase causes the inhibition of BCR signaling and surface immunoglobulin [158].
Pancreatic tumor is most of the time identified at the last stages when therapy does not save life. Li et al. characterize the pancreatic cancer stem cells (PCSCs) for the very first time [160].
In one study, there is overexpression of miR-1290 in pancreatic cancer. The direct target of miR-1290 is FoxA1 which has an effect on the transition of epithelial mesenchyma. The overexpression of miR-1290 results in the growth of cell and invasion [94].
In another study there is overexpression of miR-194 in pancreatic cancer. The target of miR-194 is DACH1 and results in the formation of the colony, the proliferation of cell, and migration (Table 22), so miR-194 causes the progression of the tumor [161].
Sr. no. | MicroRNAs | Potential targets | Function | Ref. |
---|---|---|---|---|
1 | miR-1290 | FoxA1 | Cell growth and invasion | [94] |
2 | miR-194 | DACH1 | Progression of tumor | [161] |
MicroRNAs activating the pancreatic cancer.
The growth and differentiation of the cell are regulated by LIN28, a protein that binds to the RNA [162]. The protein that is encoded by LIN28 is 25 kDa and has two binding sites for RNA: cold shock domain (CSD) and a pair of zinc fingers. In pancreatic cancer, the expression of LIN28 is increased which in turn suppresses the biosynthesis of family let-7 of microRNA (Figure 15). This family targets the genes involved in the growth and differentiation regulation [163]. This LIN28 causes the inhibition by binging to the loop present at the terminal region of let-7 family, so their processing is blocked [45, 46, 164]. This family is involved in the regulation of tumor by cyclin D1 (CCND1) inhibition [165, 166].
miRNA and pancreatic cancer.
In one study there is downregulation of miR-145 in pancreatic cancer. The decreased expression of miR-145 is due to activation of the K-ras gene. Expression of miR-145 causes the inhibition of expression of insulin growth factor-1 receptors (Table 23). Its expression causes the downregulation of genes related to cancer (SET, MCM2, SPTBN1). These genes cause growth and carcinogenesis of pancreatic cancer [161].
In the myeloid leukemia, malignant blast cells are synthesized in comparison to mononuclear cells of healthy bone marrow [167]. In myeloid leukemia the hypermethylation of the DNA is involved in tumor suppression [168]. In one study, there is overexpression of miR-204 in acute myeloid leukemia. The target of miR-204 is MEIS1 and HOXA 10 genes which disturbs the differentiation of myeloid cells. Its overexpression causes tumorigenesis [169].
In another study, miR-125b (located on chromosome 1) is overexpressed in acute myeloid leukemia. The target of miR-125b is BCL2-antagonist/killer 1 (Bak1) which enhance the proliferation of AML cell and prevent the apoptosis [169].
In another study, miR-155 (located on chromosome 21) is overexpressed in the acute myeloid leukemia. This miR-155 is located in B cell integration cluster (BIC) gene. This BIC correlated to MYC to initiate lymphomas. Overexpression of miR-155 causes the inhibition of WEE1, a regulator of the cell cycle, and hMLH1, hMLH6, and hMLH4, the genes for mismatch repair (Table 24). The result of this inhibition is increased in mutation rate in progenitor and hematopoietic stem cells [169].
Sr. no. | MicroRNAs | Potential targets | Function |
---|---|---|---|
1 | miR-204 | MEIS1 and HOXA | Tumorigenesis |
2 | miR-125b | Bak1 | Enhance proliferation and prevent apoptosis |
3 | miR-155 | WEE1, hMLH1, hMLH6, and hMLH4 | Increase mutation rate in progenitor and hematopoietic stem cells |
MicroRNAs activating the acute myeloid leukemia [169].
The known biomarker for the acute myeloid leukemia is miR-29b [167]. miR-29b causes the hypomethylation of the DNA. Sp1 transcriptional factor has the binding site for both miR-29b and DNMT1. In DNMT, it binds to its promoter and 3′UTR for miR-29b of Sp1 (specificity protein 1). Binding to the 3′UTR causes the reduced expression of Sp1, so DNMT (DNA methyltransferase) expression is also reduced (Figure 16). In acute myeloid leukemia, miR-29b results in the apoptosis when it directly targets the MCL (induced myeloid leukemia cell differentiation protein) [170]. So the expression of miR-29b is reduced in acute myeloid leukemia which leads to cancer progression as apoptosis has been decreased with reduced expression of miR-29b (Table 25).
miRNA and acute myeloid leukemia.
Sr. no. | MicroRNAs | Potential targets | Function |
---|---|---|---|
1 | miR-29b | DNMT | Apoptosis |
2 | miR-29b | MCL protein | Apoptosis |
MicroRNAs suppressing the acute myeloid leukemia [170].
In ovarian cancer, the biomarker that is used is miR-214 and it is upregulated in cancer. It binds to the 3′UTR region of phosphatase and tensin analog (PTEN) gene and causes its hypermethylation. So this is inactivated. The direct target of PTEN is Akt protein kinase B and mediates its activation by the help of PI4K3B [171]. Akt causes the downstream effects such as activation of glycogen synthase. So when PTEN is inhibited, it activates the expression of Akt. This miR-214 resists the cisplatin-mediated cell death, so it is antiapoptotic in nature (Figure 17). Cisplatin is an important factor in mediating cell death [172].
miRNA and ovarian cancer.
In a study, there is overexpression of Hsa-miR-182 in ovarian cancer. The potential target of Hsa-miR-182 is forkhead box 3 (FOXO3) and forkhead box 1 (FOXO1) which promote the differentiation and inhibition of growth (acting as a tumor suppressor). These tumor suppressor genes are suppressed, and growth and proliferation of ovarian cell are increased (Table 26) [173].
Sr. no. | MicroRNAs | Potential targets | Function | Ref. |
---|---|---|---|---|
1 | miR-214 | PTEN | Antiapoptosis | [172] |
2 | Hsa-miR-182 | FOXO3 and FOXO1 | Increased proliferation and growth | [173] |
MicroRNAs activating the ovarian cancer.
In another study, there is downregulation of miR-200 family in ovarian cancer. The direct target of miR-200 is zinc finger E-box-binding homeobox 1 and 2 (ZEB1 and ZEB2). It prevents the EMT, metastasis, invasion, and migration of tumor cell. Interleukin-8 and CXCL1 (released from tumor epithelial cells) are also the target of miR-200 and prevent the angiogenesis of tumor cell [174].
In another study there is downregulation of miR-506 in ovarian cancer, so there is cell migration invasion of the cancer cell. When this miRNA is overexpressed, it causes the expression of E-cadherin and results in inhibition of cell invasion and migration and proliferation of ovarian cancer and, via targeting SNAI2 (E-cadherin transcriptional factor), prevents the EMT induction by TGF-β (Table 27). The miR-506 directly targets the CDK4/CDK6-FOXM1 axis and initiates the senescence [175].
MicroRNAs (miRNAs) could be used as potential tool for early detection of cancer. It may upregulate or downregulate multiple targets through various mechanisms. It is upregulated as an oncogene (miRNA) and downregulated as a tumor suppressor. microRNA targets the PTEN, interferon (tumor suppressor genes), and also to the cell cycle along with the regulation of these genes [172]. MicroRNA is of vital importance because of its resistance to degradation and could be a potential candidate for clinical applications. However, its expression level can be screened in the serum/plasma (blood) by high-throughput sequencing technology. Further research for identification of novel microRNA will warrant the development of microRNA-related cancer prognosis [176, 177, 178, 179, 180].
miRISC | microRNA-associated RNA-induced silencing complex |
DGCR8 | DiGeorge syndrome chromosomal [or critical] region 8 |
EGFR | epidermal growth factor receptor |
FOXO1 | forkhead box protein O1 |
PTEN | phosphatase and tensin homolog |
TPM1 | tropomyosin alpha-1 chain |
SOX4 | SRY-related HMG-box |
CCND1 | cyclin-D1 |
DNMT | DNA methyltransferase |
MCL | induced myeloid leukemia cell differentiation protein Mcl-1 |
PKB | Akt (protein kinase B) |
You have been successfully unsubscribed.
",metaTitle:"Unsubscribe Successful",metaDescription:"You have been successfully unsubscribed.",metaKeywords:null,canonicalURL:"/page/unsubscribe-successful",contentRaw:'[{"type":"htmlEditorComponent","content":""}]'},components:[{type:"htmlEditorComponent",content:""}]},successStories:{items:[]},authorsAndEditors:{filterParams:{sort:"featured,name"},profiles:[{id:"6700",title:"Dr.",name:"Abbass A.",middleName:null,surname:"Hashim",slug:"abbass-a.-hashim",fullName:"Abbass A. Hashim",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/6700/images/1864_n.jpg",biography:"Currently I am carrying out research in several areas of interest, mainly covering work on chemical and bio-sensors, semiconductor thin film device fabrication and characterisation.\nAt the moment I have very strong interest in radiation environmental pollution and bacteriology treatment. The teams of researchers are working very hard to bring novel results in this field. I am also a member of the team in charge for the supervision of Ph.D. students in the fields of development of silicon based planar waveguide sensor devices, study of inelastic electron tunnelling in planar tunnelling nanostructures for sensing applications and development of organotellurium(IV) compounds for semiconductor applications. I am a specialist in data analysis techniques and nanosurface structure. I have served as the editor for many books, been a member of the editorial board in science journals, have published many papers and hold many patents.",institutionString:null,institution:{name:"Sheffield Hallam University",country:{name:"United Kingdom"}}},{id:"54525",title:"Prof.",name:"Abdul Latif",middleName:null,surname:"Ahmad",slug:"abdul-latif-ahmad",fullName:"Abdul Latif Ahmad",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:null},{id:"20567",title:"Prof.",name:"Ado",middleName:null,surname:"Jorio",slug:"ado-jorio",fullName:"Ado Jorio",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"Universidade Federal de Minas Gerais",country:{name:"Brazil"}}},{id:"47940",title:"Dr.",name:"Alberto",middleName:null,surname:"Mantovani",slug:"alberto-mantovani",fullName:"Alberto Mantovani",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:null},{id:"12392",title:"Mr.",name:"Alex",middleName:null,surname:"Lazinica",slug:"alex-lazinica",fullName:"Alex Lazinica",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/12392/images/7282_n.png",biography:"Alex Lazinica is the founder and CEO of IntechOpen. After obtaining a Master's degree in Mechanical Engineering, he continued his PhD studies in Robotics at the Vienna University of Technology. Here he worked as a robotic researcher with the university's Intelligent Manufacturing Systems Group as well as a guest researcher at various European universities, including the Swiss Federal Institute of Technology Lausanne (EPFL). During this time he published more than 20 scientific papers, gave presentations, served as a reviewer for major robotic journals and conferences and most importantly he co-founded and built the International Journal of Advanced Robotic Systems- world's first Open Access journal in the field of robotics. Starting this journal was a pivotal point in his career, since it was a pathway to founding IntechOpen - Open Access publisher focused on addressing academic researchers needs. Alex is a personification of IntechOpen key values being trusted, open and entrepreneurial. Today his focus is on defining the growth and development strategy for the company.",institutionString:null,institution:{name:"TU Wien",country:{name:"Austria"}}},{id:"19816",title:"Prof.",name:"Alexander",middleName:null,surname:"Kokorin",slug:"alexander-kokorin",fullName:"Alexander Kokorin",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/19816/images/1607_n.jpg",biography:"Alexander I. Kokorin: born: 1947, Moscow; DSc., PhD; Principal Research Fellow (Research Professor) of Department of Kinetics and Catalysis, N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow.\r\nArea of research interests: physical chemistry of complex-organized molecular and nanosized systems, including polymer-metal complexes; the surface of doped oxide semiconductors. He is an expert in structural, absorptive, catalytic and photocatalytic properties, in structural organization and dynamic features of ionic liquids, in magnetic interactions between paramagnetic centers. The author or co-author of 3 books, over 200 articles and reviews in scientific journals and books. He is an actual member of the International EPR/ESR Society, European Society on Quantum Solar Energy Conversion, Moscow House of Scientists, of the Board of Moscow Physical Society.",institutionString:null,institution:{name:"Semenov Institute of Chemical Physics",country:{name:"Russia"}}},{id:"62389",title:"PhD.",name:"Ali Demir",middleName:null,surname:"Sezer",slug:"ali-demir-sezer",fullName:"Ali Demir Sezer",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/62389/images/3413_n.jpg",biography:"Dr. Ali Demir Sezer has a Ph.D. from Pharmaceutical Biotechnology at the Faculty of Pharmacy, University of Marmara (Turkey). He is the member of many Pharmaceutical Associations and acts as a reviewer of scientific journals and European projects under different research areas such as: drug delivery systems, nanotechnology and pharmaceutical biotechnology. Dr. Sezer is the author of many scientific publications in peer-reviewed journals and poster communications. Focus of his research activity is drug delivery, physico-chemical characterization and biological evaluation of biopolymers micro and nanoparticles as modified drug delivery system, and colloidal drug carriers (liposomes, nanoparticles etc.).",institutionString:null,institution:{name:"Marmara University",country:{name:"Turkey"}}},{id:"61051",title:"Prof.",name:"Andrea",middleName:null,surname:"Natale",slug:"andrea-natale",fullName:"Andrea Natale",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:null},{id:"100762",title:"Prof.",name:"Andrea",middleName:null,surname:"Natale",slug:"andrea-natale",fullName:"Andrea Natale",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"St David's Medical Center",country:{name:"United States of America"}}},{id:"107416",title:"Dr.",name:"Andrea",middleName:null,surname:"Natale",slug:"andrea-natale",fullName:"Andrea Natale",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"Texas Cardiac Arrhythmia",country:{name:"United States of America"}}},{id:"64434",title:"Dr.",name:"Angkoon",middleName:null,surname:"Phinyomark",slug:"angkoon-phinyomark",fullName:"Angkoon Phinyomark",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/64434/images/2619_n.jpg",biography:"My name is Angkoon Phinyomark. I received a B.Eng. degree in Computer Engineering with First Class Honors in 2008 from Prince of Songkla University, Songkhla, Thailand, where I received a Ph.D. degree in Electrical Engineering. My research interests are primarily in the area of biomedical signal processing and classification notably EMG (electromyography signal), EOG (electrooculography signal), and EEG (electroencephalography signal), image analysis notably breast cancer analysis and optical coherence tomography, and rehabilitation engineering. I became a student member of IEEE in 2008. During October 2011-March 2012, I had worked at School of Computer Science and Electronic Engineering, University of Essex, Colchester, Essex, United Kingdom. In addition, during a B.Eng. I had been a visiting research student at Faculty of Computer Science, University of Murcia, Murcia, Spain for three months.\n\nI have published over 40 papers during 5 years in refereed journals, books, and conference proceedings in the areas of electro-physiological signals processing and classification, notably EMG and EOG signals, fractal analysis, wavelet analysis, texture analysis, feature extraction and machine learning algorithms, and assistive and rehabilitative devices. I have several computer programming language certificates, i.e. Sun Certified Programmer for the Java 2 Platform 1.4 (SCJP), Microsoft Certified Professional Developer, Web Developer (MCPD), Microsoft Certified Technology Specialist, .NET Framework 2.0 Web (MCTS). I am a Reviewer for several refereed journals and international conferences, such as IEEE Transactions on Biomedical Engineering, IEEE Transactions on Industrial Electronics, Optic Letters, Measurement Science Review, and also a member of the International Advisory Committee for 2012 IEEE Business Engineering and Industrial Applications and 2012 IEEE Symposium on Business, Engineering and Industrial Applications.",institutionString:null,institution:{name:"Joseph Fourier University",country:{name:"France"}}},{id:"55578",title:"Dr.",name:"Antonio",middleName:null,surname:"Jurado-Navas",slug:"antonio-jurado-navas",fullName:"Antonio Jurado-Navas",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/55578/images/4574_n.png",biography:"Antonio Jurado-Navas received the M.S. degree (2002) and the Ph.D. degree (2009) in Telecommunication Engineering, both from the University of Málaga (Spain). He first worked as a consultant at Vodafone-Spain. From 2004 to 2011, he was a Research Assistant with the Communications Engineering Department at the University of Málaga. In 2011, he became an Assistant Professor in the same department. From 2012 to 2015, he was with Ericsson Spain, where he was working on geo-location\ntools for third generation mobile networks. Since 2015, he is a Marie-Curie fellow at the Denmark Technical University. His current research interests include the areas of mobile communication systems and channel modeling in addition to atmospheric optical communications, adaptive optics and statistics",institutionString:null,institution:{name:"University of Malaga",country:{name:"Spain"}}}],filtersByRegion:[{group:"region",caption:"North America",value:1,count:5681},{group:"region",caption:"Middle and South America",value:2,count:5161},{group:"region",caption:"Africa",value:3,count:1683},{group:"region",caption:"Asia",value:4,count:10200},{group:"region",caption:"Australia and Oceania",value:5,count:886},{group:"region",caption:"Europe",value:6,count:15610}],offset:12,limit:12,total:117095},chapterEmbeded:{data:{}},editorApplication:{success:null,errors:{}},ofsBooks:{filterParams:{sort:"dateendthirdsteppublish"},books:[],filtersByTopic:[{group:"topic",caption:"Agricultural and Biological Sciences",value:5,count:9},{group:"topic",caption:"Biochemistry, Genetics and Molecular Biology",value:6,count:17},{group:"topic",caption:"Business, Management and Economics",value:7,count:2},{group:"topic",caption:"Chemistry",value:8,count:7},{group:"topic",caption:"Computer and Information Science",value:9,count:10},{group:"topic",caption:"Earth and Planetary Sciences",value:10,count:5},{group:"topic",caption:"Engineering",value:11,count:15},{group:"topic",caption:"Environmental Sciences",value:12,count:2},{group:"topic",caption:"Immunology and Microbiology",value:13,count:5},{group:"topic",caption:"Materials Science",value:14,count:4},{group:"topic",caption:"Mathematics",value:15,count:1},{group:"topic",caption:"Medicine",value:16,count:60},{group:"topic",caption:"Nanotechnology and Nanomaterials",value:17,count:1},{group:"topic",caption:"Neuroscience",value:18,count:1},{group:"topic",caption:"Pharmacology, Toxicology and Pharmaceutical Science",value:19,count:6},{group:"topic",caption:"Physics",value:20,count:2},{group:"topic",caption:"Psychology",value:21,count:3},{group:"topic",caption:"Robotics",value:22,count:1},{group:"topic",caption:"Social Sciences",value:23,count:3},{group:"topic",caption:"Technology",value:24,count:1},{group:"topic",caption:"Veterinary Medicine and Science",value:25,count:2}],offset:0,limit:12,total:null},popularBooks:{featuredBooks:[{type:"book",id:"9343",title:"Trace Metals in the Environment",subtitle:"New Approaches and Recent Advances",isOpenForSubmission:!1,hash:"ae07e345bc2ce1ebbda9f70c5cd12141",slug:"trace-metals-in-the-environment-new-approaches-and-recent-advances",bookSignature:"Mario Alfonso Murillo-Tovar, Hugo Saldarriaga-Noreña and Agnieszka Saeid",coverURL:"https://cdn.intechopen.com/books/images_new/9343.jpg",editors:[{id:"255959",title:"Dr.",name:"Mario Alfonso",middleName:null,surname:"Murillo-Tovar",slug:"mario-alfonso-murillo-tovar",fullName:"Mario Alfonso Murillo-Tovar"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"7769",title:"Medical Isotopes",subtitle:null,isOpenForSubmission:!1,hash:"f8d3c5a6c9a42398e56b4e82264753f7",slug:"medical-isotopes",bookSignature:"Syed Ali Raza Naqvi and Muhammad Babar Imrani",coverURL:"https://cdn.intechopen.com/books/images_new/7769.jpg",editors:[{id:"259190",title:"Dr.",name:"Syed Ali Raza",middleName:null,surname:"Naqvi",slug:"syed-ali-raza-naqvi",fullName:"Syed Ali Raza Naqvi"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9376",title:"Contemporary Developments and Perspectives in International Health Security",subtitle:"Volume 1",isOpenForSubmission:!1,hash:"b9a00b84cd04aae458fb1d6c65795601",slug:"contemporary-developments-and-perspectives-in-international-health-security-volume-1",bookSignature:"Stanislaw P. Stawicki, Michael S. Firstenberg, Sagar C. Galwankar, Ricardo Izurieta and Thomas Papadimos",coverURL:"https://cdn.intechopen.com/books/images_new/9376.jpg",editors:[{id:"181694",title:"Dr.",name:"Stanislaw P.",middleName:null,surname:"Stawicki",slug:"stanislaw-p.-stawicki",fullName:"Stanislaw P. Stawicki"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"7831",title:"Sustainability in Urban Planning and Design",subtitle:null,isOpenForSubmission:!1,hash:"c924420492c8c2c9751e178d025f4066",slug:"sustainability-in-urban-planning-and-design",bookSignature:"Amjad Almusaed, Asaad Almssad and Linh Truong - Hong",coverURL:"https://cdn.intechopen.com/books/images_new/7831.jpg",editors:[{id:"110471",title:"Dr.",name:"Amjad",middleName:"Zaki",surname:"Almusaed",slug:"amjad-almusaed",fullName:"Amjad Almusaed"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9279",title:"Concepts, Applications and Emerging Opportunities in Industrial Engineering",subtitle:null,isOpenForSubmission:!1,hash:"9bfa87f9b627a5468b7c1e30b0eea07a",slug:"concepts-applications-and-emerging-opportunities-in-industrial-engineering",bookSignature:"Gary Moynihan",coverURL:"https://cdn.intechopen.com/books/images_new/9279.jpg",editors:[{id:"16974",title:"Dr.",name:"Gary",middleName:null,surname:"Moynihan",slug:"gary-moynihan",fullName:"Gary Moynihan"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"7807",title:"A Closer Look at Organizational Culture in Action",subtitle:null,isOpenForSubmission:!1,hash:"05c608b9271cc2bc711f4b28748b247b",slug:"a-closer-look-at-organizational-culture-in-action",bookSignature:"Süleyman Davut Göker",coverURL:"https://cdn.intechopen.com/books/images_new/7807.jpg",editors:[{id:"190035",title:"Associate Prof.",name:"Süleyman Davut",middleName:null,surname:"Göker",slug:"suleyman-davut-goker",fullName:"Süleyman Davut Göker"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"7796",title:"Human 4.0",subtitle:"From Biology to Cybernetic",isOpenForSubmission:!1,hash:"5ac5c052d3a593d5c4f4df66d005e5af",slug:"human-4-0-from-biology-to-cybernetic",bookSignature:"Yves Rybarczyk",coverURL:"https://cdn.intechopen.com/books/images_new/7796.jpg",editors:[{id:"72920",title:"Prof.",name:"Yves",middleName:"Philippe",surname:"Rybarczyk",slug:"yves-rybarczyk",fullName:"Yves Rybarczyk"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9711",title:"Pests, Weeds and Diseases in Agricultural Crop and Animal Husbandry Production",subtitle:null,isOpenForSubmission:!1,hash:"12cf675f1e433135dd5bf5df7cec124f",slug:"pests-weeds-and-diseases-in-agricultural-crop-and-animal-husbandry-production",bookSignature:"Dimitrios Kontogiannatos, Anna Kourti and Kassio Ferreira Mendes",coverURL:"https://cdn.intechopen.com/books/images_new/9711.jpg",editors:[{id:"196691",title:"Dr.",name:"Dimitrios",middleName:null,surname:"Kontogiannatos",slug:"dimitrios-kontogiannatos",fullName:"Dimitrios Kontogiannatos"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10178",title:"Environmental Emissions",subtitle:null,isOpenForSubmission:!1,hash:"febf21ec717bfe20ae25a9dab9b5d438",slug:"environmental-emissions",bookSignature:"Richard Viskup",coverURL:"https://cdn.intechopen.com/books/images_new/10178.jpg",editors:[{id:"103742",title:"Dr.",name:"Richard",middleName:null,surname:"Viskup",slug:"richard-viskup",fullName:"Richard Viskup"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"8511",title:"Cyberspace",subtitle:null,isOpenForSubmission:!1,hash:"8c1cdeb133dbe6cc1151367061c1bba6",slug:"cyberspace",bookSignature:"Evon Abu-Taieh, Abdelkrim El Mouatasim and Issam H. Al Hadid",coverURL:"https://cdn.intechopen.com/books/images_new/8511.jpg",editors:[{id:"223522",title:"Dr.",name:"Evon",middleName:"M.O.",surname:"Abu-Taieh",slug:"evon-abu-taieh",fullName:"Evon Abu-Taieh"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9534",title:"Banking and Finance",subtitle:null,isOpenForSubmission:!1,hash:"af14229738af402c3b595d7e124dce82",slug:"banking-and-finance",bookSignature:"Razali Haron, Maizaitulaidawati Md Husin and Michael Murg",coverURL:"https://cdn.intechopen.com/books/images_new/9534.jpg",editors:[{id:"206517",title:"Prof.",name:"Razali",middleName:null,surname:"Haron",slug:"razali-haron",fullName:"Razali Haron"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"2160",title:"MATLAB",subtitle:"A Fundamental Tool for Scientific Computing and Engineering Applications - Volume 1",isOpenForSubmission:!1,hash:"dd9c658341fbd264ed4f8d9e6aa8ca29",slug:"matlab-a-fundamental-tool-for-scientific-computing-and-engineering-applications-volume-1",bookSignature:"Vasilios N. Katsikis",coverURL:"https://cdn.intechopen.com/books/images_new/2160.jpg",editors:[{id:"12289",title:"Prof.",name:"Vasilios",middleName:"N.",surname:"Katsikis",slug:"vasilios-katsikis",fullName:"Vasilios Katsikis"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}}],offset:12,limit:12,total:5126},hotBookTopics:{hotBooks:[],offset:0,limit:12,total:null},publish:{},publishingProposal:{success:null,errors:{}},books:{featuredBooks:[{type:"book",id:"9208",title:"Welding",subtitle:"Modern Topics",isOpenForSubmission:!1,hash:"7d6be076ccf3a3f8bd2ca52d86d4506b",slug:"welding-modern-topics",bookSignature:"Sadek Crisóstomo Absi Alfaro, Wojciech Borek and Błażej Tomiczek",coverURL:"https://cdn.intechopen.com/books/images_new/9208.jpg",editors:[{id:"65292",title:"Prof.",name:"Sadek Crisostomo Absi",middleName:"C. Absi",surname:"Alfaro",slug:"sadek-crisostomo-absi-alfaro",fullName:"Sadek Crisostomo Absi Alfaro"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9139",title:"Topics in Primary Care Medicine",subtitle:null,isOpenForSubmission:!1,hash:"ea774a4d4c1179da92a782e0ae9cde92",slug:"topics-in-primary-care-medicine",bookSignature:"Thomas F. Heston",coverURL:"https://cdn.intechopen.com/books/images_new/9139.jpg",editors:[{id:"217926",title:"Dr.",name:"Thomas F.",middleName:null,surname:"Heston",slug:"thomas-f.-heston",fullName:"Thomas F. Heston"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"8697",title:"Virtual Reality and Its Application in Education",subtitle:null,isOpenForSubmission:!1,hash:"ee01b5e387ba0062c6b0d1e9227bda05",slug:"virtual-reality-and-its-application-in-education",bookSignature:"Dragan Cvetković",coverURL:"https://cdn.intechopen.com/books/images_new/8697.jpg",editors:[{id:"101330",title:"Dr.",name:"Dragan",middleName:"Mladen",surname:"Cvetković",slug:"dragan-cvetkovic",fullName:"Dragan Cvetković"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9785",title:"Endometriosis",subtitle:null,isOpenForSubmission:!1,hash:"f457ca61f29cf7e8bc191732c50bb0ce",slug:"endometriosis",bookSignature:"Courtney Marsh",coverURL:"https://cdn.intechopen.com/books/images_new/9785.jpg",editors:[{id:"255491",title:"Dr.",name:"Courtney",middleName:null,surname:"Marsh",slug:"courtney-marsh",fullName:"Courtney Marsh"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9343",title:"Trace Metals in the Environment",subtitle:"New Approaches and Recent Advances",isOpenForSubmission:!1,hash:"ae07e345bc2ce1ebbda9f70c5cd12141",slug:"trace-metals-in-the-environment-new-approaches-and-recent-advances",bookSignature:"Mario Alfonso Murillo-Tovar, Hugo Saldarriaga-Noreña and Agnieszka Saeid",coverURL:"https://cdn.intechopen.com/books/images_new/9343.jpg",editors:[{id:"255959",title:"Dr.",name:"Mario Alfonso",middleName:null,surname:"Murillo-Tovar",slug:"mario-alfonso-murillo-tovar",fullName:"Mario Alfonso Murillo-Tovar"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"8468",title:"Sheep Farming",subtitle:"An Approach to Feed, Growth and Sanity",isOpenForSubmission:!1,hash:"838f08594850bc04aa14ec873ed1b96f",slug:"sheep-farming-an-approach-to-feed-growth-and-sanity",bookSignature:"António Monteiro",coverURL:"https://cdn.intechopen.com/books/images_new/8468.jpg",editors:[{id:"190314",title:"Prof.",name:"António",middleName:"Cardoso",surname:"Monteiro",slug:"antonio-monteiro",fullName:"António Monteiro"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"8816",title:"Financial Crises",subtitle:"A Selection of Readings",isOpenForSubmission:!1,hash:"6f2f49fb903656e4e54280c79fabd10c",slug:"financial-crises-a-selection-of-readings",bookSignature:"Stelios Markoulis",coverURL:"https://cdn.intechopen.com/books/images_new/8816.jpg",editors:[{id:"237863",title:"Dr.",name:"Stelios",middleName:null,surname:"Markoulis",slug:"stelios-markoulis",fullName:"Stelios Markoulis"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"7831",title:"Sustainability in Urban Planning and Design",subtitle:null,isOpenForSubmission:!1,hash:"c924420492c8c2c9751e178d025f4066",slug:"sustainability-in-urban-planning-and-design",bookSignature:"Amjad Almusaed, Asaad Almssad and Linh Truong - Hong",coverURL:"https://cdn.intechopen.com/books/images_new/7831.jpg",editors:[{id:"110471",title:"Dr.",name:"Amjad",middleName:"Zaki",surname:"Almusaed",slug:"amjad-almusaed",fullName:"Amjad Almusaed"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9376",title:"Contemporary Developments and Perspectives in International Health Security",subtitle:"Volume 1",isOpenForSubmission:!1,hash:"b9a00b84cd04aae458fb1d6c65795601",slug:"contemporary-developments-and-perspectives-in-international-health-security-volume-1",bookSignature:"Stanislaw P. Stawicki, Michael S. Firstenberg, Sagar C. Galwankar, Ricardo Izurieta and Thomas Papadimos",coverURL:"https://cdn.intechopen.com/books/images_new/9376.jpg",editors:[{id:"181694",title:"Dr.",name:"Stanislaw P.",middleName:null,surname:"Stawicki",slug:"stanislaw-p.-stawicki",fullName:"Stanislaw P. Stawicki"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"7769",title:"Medical Isotopes",subtitle:null,isOpenForSubmission:!1,hash:"f8d3c5a6c9a42398e56b4e82264753f7",slug:"medical-isotopes",bookSignature:"Syed Ali Raza Naqvi and Muhammad Babar Imrani",coverURL:"https://cdn.intechopen.com/books/images_new/7769.jpg",editors:[{id:"259190",title:"Dr.",name:"Syed Ali Raza",middleName:null,surname:"Naqvi",slug:"syed-ali-raza-naqvi",fullName:"Syed Ali Raza Naqvi"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}}],latestBooks:[{type:"book",id:"8468",title:"Sheep Farming",subtitle:"An Approach to Feed, Growth and Sanity",isOpenForSubmission:!1,hash:"838f08594850bc04aa14ec873ed1b96f",slug:"sheep-farming-an-approach-to-feed-growth-and-sanity",bookSignature:"António Monteiro",coverURL:"https://cdn.intechopen.com/books/images_new/8468.jpg",editedByType:"Edited by",editors:[{id:"190314",title:"Prof.",name:"António",middleName:"Cardoso",surname:"Monteiro",slug:"antonio-monteiro",fullName:"António Monteiro"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9523",title:"Oral and Maxillofacial Surgery",subtitle:null,isOpenForSubmission:!1,hash:"5eb6ec2db961a6c8965d11180a58d5c1",slug:"oral-and-maxillofacial-surgery",bookSignature:"Gokul Sridharan",coverURL:"https://cdn.intechopen.com/books/images_new/9523.jpg",editedByType:"Edited by",editors:[{id:"82453",title:"Dr.",name:"Gokul",middleName:null,surname:"Sridharan",slug:"gokul-sridharan",fullName:"Gokul Sridharan"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9785",title:"Endometriosis",subtitle:null,isOpenForSubmission:!1,hash:"f457ca61f29cf7e8bc191732c50bb0ce",slug:"endometriosis",bookSignature:"Courtney Marsh",coverURL:"https://cdn.intechopen.com/books/images_new/9785.jpg",editedByType:"Edited by",editors:[{id:"255491",title:"Dr.",name:"Courtney",middleName:null,surname:"Marsh",slug:"courtney-marsh",fullName:"Courtney Marsh"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9018",title:"Some RNA Viruses",subtitle:null,isOpenForSubmission:!1,hash:"a5cae846dbe3692495fc4add2f60fd84",slug:"some-rna-viruses",bookSignature:"Yogendra Shah and Eltayb Abuelzein",coverURL:"https://cdn.intechopen.com/books/images_new/9018.jpg",editedByType:"Edited by",editors:[{id:"278914",title:"Ph.D.",name:"Yogendra",middleName:null,surname:"Shah",slug:"yogendra-shah",fullName:"Yogendra Shah"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"8816",title:"Financial Crises",subtitle:"A Selection of Readings",isOpenForSubmission:!1,hash:"6f2f49fb903656e4e54280c79fabd10c",slug:"financial-crises-a-selection-of-readings",bookSignature:"Stelios Markoulis",coverURL:"https://cdn.intechopen.com/books/images_new/8816.jpg",editedByType:"Edited by",editors:[{id:"237863",title:"Dr.",name:"Stelios",middleName:null,surname:"Markoulis",slug:"stelios-markoulis",fullName:"Stelios Markoulis"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9585",title:"Advances in Complex Valvular Disease",subtitle:null,isOpenForSubmission:!1,hash:"ef64f11e211621ecfe69c46e60e7ca3d",slug:"advances-in-complex-valvular-disease",bookSignature:"Michael S. Firstenberg and Imran Khan",coverURL:"https://cdn.intechopen.com/books/images_new/9585.jpg",editedByType:"Edited by",editors:[{id:"64343",title:null,name:"Michael S.",middleName:"S",surname:"Firstenberg",slug:"michael-s.-firstenberg",fullName:"Michael S. Firstenberg"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10150",title:"Smart Manufacturing",subtitle:"When Artificial Intelligence Meets the Internet of Things",isOpenForSubmission:!1,hash:"87004a19de13702d042f8ff96d454698",slug:"smart-manufacturing-when-artificial-intelligence-meets-the-internet-of-things",bookSignature:"Tan Yen Kheng",coverURL:"https://cdn.intechopen.com/books/images_new/10150.jpg",editedByType:"Edited by",editors:[{id:"78857",title:"Dr.",name:"Tan Yen",middleName:null,surname:"Kheng",slug:"tan-yen-kheng",fullName:"Tan Yen Kheng"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9386",title:"Direct Numerical Simulations",subtitle:"An Introduction and Applications",isOpenForSubmission:!1,hash:"158a3a0fdba295d21ff23326f5a072d5",slug:"direct-numerical-simulations-an-introduction-and-applications",bookSignature:"Srinivasa Rao",coverURL:"https://cdn.intechopen.com/books/images_new/9386.jpg",editedByType:"Edited by",editors:[{id:"6897",title:"Dr.",name:"Srinivasa",middleName:"P",surname:"Rao",slug:"srinivasa-rao",fullName:"Srinivasa Rao"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9139",title:"Topics in Primary Care Medicine",subtitle:null,isOpenForSubmission:!1,hash:"ea774a4d4c1179da92a782e0ae9cde92",slug:"topics-in-primary-care-medicine",bookSignature:"Thomas F. Heston",coverURL:"https://cdn.intechopen.com/books/images_new/9139.jpg",editedByType:"Edited by",editors:[{id:"217926",title:"Dr.",name:"Thomas F.",middleName:null,surname:"Heston",slug:"thomas-f.-heston",fullName:"Thomas F. Heston"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9208",title:"Welding",subtitle:"Modern Topics",isOpenForSubmission:!1,hash:"7d6be076ccf3a3f8bd2ca52d86d4506b",slug:"welding-modern-topics",bookSignature:"Sadek Crisóstomo Absi Alfaro, Wojciech Borek and Błażej Tomiczek",coverURL:"https://cdn.intechopen.com/books/images_new/9208.jpg",editedByType:"Edited by",editors:[{id:"65292",title:"Prof.",name:"Sadek Crisostomo Absi",middleName:"C. Absi",surname:"Alfaro",slug:"sadek-crisostomo-absi-alfaro",fullName:"Sadek Crisostomo Absi Alfaro"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}}]},subject:{topic:{id:"515",title:"Computer Gaming",slug:"computer-gaming",parent:{title:"Artificial Intelligence",slug:"computer-and-information-science-artificial-intelligence"},numberOfBooks:2,numberOfAuthorsAndEditors:1,numberOfWosCitations:64,numberOfCrossrefCitations:41,numberOfDimensionsCitations:102,videoUrl:null,fallbackUrl:null,description:null},booksByTopicFilter:{topicSlug:"computer-gaming",sort:"-publishedDate",limit:12,offset:0},booksByTopicCollection:[{type:"book",id:"3751",title:"Machine Learning",subtitle:null,isOpenForSubmission:!1,hash:"5094182fa13e485c45ab489be59beed4",slug:"machine-learning",bookSignature:"Yagang Zhang",coverURL:"https://cdn.intechopen.com/books/images_new/3751.jpg",editedByType:"Edited by",editors:[{id:"2987",title:"Dr.",name:"Yagang",middleName:null,surname:"Zhang",slug:"yagang-zhang",fullName:"Yagang Zhang"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"3752",title:"New Advances in Machine Learning",subtitle:null,isOpenForSubmission:!1,hash:"5b5624fb61f120a1a6dbdecc4cc48dfb",slug:"new-advances-in-machine-learning",bookSignature:"Yagang Zhang",coverURL:"https://cdn.intechopen.com/books/images_new/3752.jpg",editedByType:"Edited by",editors:[{id:"2987",title:"Dr.",name:"Yagang",middleName:null,surname:"Zhang",slug:"yagang-zhang",fullName:"Yagang Zhang"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}}],booksByTopicTotal:2,mostCitedChapters:[{id:"10694",doi:"10.5772/9385",title:"Types of Machine Learning Algorithms",slug:"types-of-machine-learning-algorithms",totalDownloads:9622,totalCrossrefCites:12,totalDimensionsCites:41,book:{slug:"new-advances-in-machine-learning",title:"New Advances in Machine Learning",fullTitle:"New Advances in Machine Learning"},signatures:"Taiwo Oladipupo Ayodele",authors:null},{id:"10448",doi:"10.5772/9157",title:"Adaptive Basis Function Construction: An Approach for Adaptive Building of Sparse Polynomial Regression Models",slug:"adaptive-basis-function-construction-an-approach-for-adaptive-building-of-sparse-polynomial-regressi",totalDownloads:1601,totalCrossrefCites:12,totalDimensionsCites:15,book:{slug:"machine-learning",title:"Machine Learning",fullTitle:"Machine Learning"},signatures:"Gints Jekabsons",authors:null},{id:"10698",doi:"10.5772/9389",title:"Ant Colony Optimization",slug:"ant-colony-optimization",totalDownloads:2153,totalCrossrefCites:1,totalDimensionsCites:7,book:{slug:"new-advances-in-machine-learning",title:"New Advances in Machine Learning",fullTitle:"New Advances in Machine Learning"},signatures:"Benlian Xu, Jihong Zhu and Qinlan Chen",authors:null}],mostDownloadedChaptersLast30Days:[{id:"10432",title:"Automated Detection and Analysis of Particle Beams in Laser-Plasman Accelerator Simulations",slug:"automated-detection-and-analysis-of-particle-beams-in-laser-plasman-accelerator-simulations",totalDownloads:1841,totalCrossrefCites:0,totalDimensionsCites:1,book:{slug:"machine-learning",title:"Machine Learning",fullTitle:"Machine Learning"},signatures:"Daniela M. Ushizima, Cameron G. Geddes, Estelle Cormier-Michel, E.Wes Bethel, Janet Jacobsen, Prabhat, Oliver Rubel, Gunther Weber, Bernd Hamann, Peter Messmer and Hans Haggen",authors:null},{id:"10694",title:"Types of Machine Learning Algorithms",slug:"types-of-machine-learning-algorithms",totalDownloads:9622,totalCrossrefCites:12,totalDimensionsCites:41,book:{slug:"new-advances-in-machine-learning",title:"New Advances in Machine Learning",fullTitle:"New Advances in Machine Learning"},signatures:"Taiwo Oladipupo Ayodele",authors:null},{id:"10447",title:"Machine Learning: When and Where the Horses Went Astray?",slug:"machine-learning-when-and-where-the-horses-went-astray-",totalDownloads:1625,totalCrossrefCites:1,totalDimensionsCites:3,book:{slug:"machine-learning",title:"Machine Learning",fullTitle:"Machine Learning"},signatures:"Emanuel Diamant",authors:null},{id:"10690",title:"An Intelligent System for Container Image Recognition using ART2-based Self-Organizing Supervised Learning Algorithm",slug:"an-intelligent-system-for-container-image-recognition-using-art2-based-self-organizing-supervised-le",totalDownloads:1945,totalCrossrefCites:2,totalDimensionsCites:2,book:{slug:"new-advances-in-machine-learning",title:"New Advances in Machine Learning",fullTitle:"New Advances in Machine Learning"},signatures:"Kwang-Baek Kim, Sungshin Kim and Young Woon Woo",authors:null},{id:"10683",title:"Machine Learning Overview",slug:"machine-learning-overview",totalDownloads:3078,totalCrossrefCites:3,totalDimensionsCites:3,book:{slug:"new-advances-in-machine-learning",title:"New Advances in Machine Learning",fullTitle:"New Advances in Machine Learning"},signatures:"Taiwo Oladipupo Ayodele",authors:null},{id:"10703",title:"Introduction to Machine Learning",slug:"introduction-to-machine-learning",totalDownloads:2914,totalCrossrefCites:1,totalDimensionsCites:7,book:{slug:"new-advances-in-machine-learning",title:"New Advances in Machine Learning",fullTitle:"New Advances in Machine Learning"},signatures:"Taiwo Oladipupo Ayodele",authors:null},{id:"10684",title:"Knowledge Structures for Visualising Advanced Research and Trends",slug:"knowledge-structures-for-visualising-advanced-research-and-trends",totalDownloads:1569,totalCrossrefCites:0,totalDimensionsCites:0,book:{slug:"new-advances-in-machine-learning",title:"New Advances in Machine Learning",fullTitle:"New Advances in Machine Learning"},signatures:"Maria R. Lee and Tsung Teng Chen",authors:null},{id:"10428",title:"SOMs for Machine Learning",slug:"soms-for-machine-learning",totalDownloads:1451,totalCrossrefCites:1,totalDimensionsCites:0,book:{slug:"machine-learning",title:"Machine Learning",fullTitle:"Machine Learning"},signatures:"Iren Valova, Derek Beaton and Daniel MacLean",authors:null},{id:"10446",title:"Relational Analysis for Clustering Consensus",slug:"relational-analysis-for-clustering-consensus",totalDownloads:1558,totalCrossrefCites:1,totalDimensionsCites:1,book:{slug:"machine-learning",title:"Machine Learning",fullTitle:"Machine Learning"},signatures:"Mustapha Lebbah, Younes Bennani, Nistor Grozavu and Hamid Benhadda",authors:null},{id:"10687",title:"Methods for Pattern Classification",slug:"methods-for-pattern-classification",totalDownloads:1710,totalCrossrefCites:0,totalDimensionsCites:0,book:{slug:"new-advances-in-machine-learning",title:"New Advances in Machine Learning",fullTitle:"New Advances in Machine Learning"},signatures:"Yizhang Guan",authors:null}],onlineFirstChaptersFilter:{topicSlug:"computer-gaming",limit:3,offset:0},onlineFirstChaptersCollection:[],onlineFirstChaptersTotal:0},preDownload:{success:null,errors:{}},aboutIntechopen:{},privacyPolicy:{},peerReviewing:{},howOpenAccessPublishingWithIntechopenWorks:{},sponsorshipBooks:{sponsorshipBooks:[{type:"book",id:"10176",title:"Microgrids and Local Energy Systems",subtitle:null,isOpenForSubmission:!0,hash:"c32b4a5351a88f263074b0d0ca813a9c",slug:null,bookSignature:"Prof. Nick Jenkins",coverURL:"https://cdn.intechopen.com/books/images_new/10176.jpg",editedByType:null,editors:[{id:"55219",title:"Prof.",name:"Nick",middleName:null,surname:"Jenkins",slug:"nick-jenkins",fullName:"Nick Jenkins"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}}],offset:8,limit:8,total:1},route:{name:"profile.detail",path:"/profiles/102158/vitaly-kober",hash:"",query:{},params:{id:"102158",slug:"vitaly-kober"},fullPath:"/profiles/102158/vitaly-kober",meta:{},from:{name:null,path:"/",hash:"",query:{},params:{},fullPath:"/",meta:{}}}},function(){var e;(e=document.currentScript||document.scripts[document.scripts.length-1]).parentNode.removeChild(e)}()