Advantages and limitations of phytoremediation [3,7,8,48,49].
\r\n\tsustainability, financial and social investigations, and disruptive technologies. This book also covers urban resilience by considering different factors: health and wellbeing; economy and society; infrastructure and environment; leadership and strategy.
\r\n\r\n\tAs a self-contained collection of scholarly papers, the book will target an audience of practicing researchers, academics, PhD students and other scientists. Since it will be published as an Open Access publication, it will allow unrestricted online access to chapters with no reading or subscription fees.
\r\n\t
Contaminated soils and residues can be remediated by various methods, such as: removal, isolation, incineration, solidification/stabilization, vitrification, thermal treatment, solvent extraction, chemical oxidation, etc. These methods have the disadvantage of being very expensive and in some cases, they involve the movement of contaminated materials to treatment sites thus, adding risks of secondary contamination [1-3]. Therefore, currently preference is being given to in situ methods that are less environmentally disruptive and more economical. In this context, biotechnology offers phytoremediation techniques as a suitable alternative.
Phytoremediation can be understood as the use of plants (trees, shrubs, grasses and aquatic plants) and their associated microorganisms in order to remove, degrade or isolate toxic substances from the environment [3-8]. The word “phytoremediation” derives from the Greek «phyton», meaning “plant”, and Latin «remedium», which means “to remedy” or “to correct”.
Substances that may be subjected to phytoremediation include metals (Pb, Zn, Cd, Cu, Ni, Hg), metalloids (As, Sb), inorganic compounds (NO3- NH4+, PO43-), radioactive chemical elements (U, Cs, Sr), petroleum hydrocarbons (BTEX), pesticides and herbicides (atrazine, bentazone, chlorinated and nitroaromatic compounds), explosives (TNT, DNT), chlorinated solvents (TCE, PCE) and industrial organic wastes (PCPs, PAHs), and others [5].
Phytoremediation techniques include different modalities, depending on the chemical nature and properties of the contaminant (if it is inert, volatile or subject to degradation in the plant or in the soil) and the plant characteristics (Figure 1). Thus, phytoremediation essentially comprise six different strategies, though more than one may be used by the plant simultaneously.
Schematic representation of phytoremediation strategies.
\n\t\t\t\t\t\tPhytodegradation (Phytotransformation): organic contaminants are degraded (metabolized) or mineralized inside plant cells by specific enzymes that include nitroreductases (degradation of nitroaromatic compounds), dehalogenases (degradation of chlorinated solvents and pesticides) and laccases (degradation of anilines). Populus species and Myriophyllium spicatum are examples of plants that have these enzymatic systems [9,10].
\n\t\t\t\t\t\tPhytostabilization (Phytoimmobilization): contaminants, organic or inorganic, are incorporated into the lignin of the cell wall of roots cells or into humus. Metals are precipitated as insoluble forms by direct action of root exudates and subsequently trapped in the soil matrix. The main objective is to avoid mobilization of contaminants and limit their diffusion in the soil [3,11-13]. Species of genera Haumaniastrum, Eragrostis, Ascolepis, Gladiolus and Alyssum are examples of plants cultivated for this purpose.
Phytovolatilization: this technique relies on the ability of some plants to absorb and volatilize certain metals/metalloids. Some element ions of the groups IIB, VA and VIA of the periodic table (specifically Hg, Se and As) are absorbed by the roots, converted into non-toxic forms, and then released into the atmosphere. As examples the species Astragalus bisulcatus and Stanleya pinnata for Se or transgenic plants (with bacterial genes) of Arabidopsis thaliana, Nicotiana tabacum, Liriodendron tulipifera or Brassica napus for Hg can be mentioned [13-18]. This technique can also be used for organic compounds.
\n\t\t\t\t\t\tPhytoextraction (Phytoaccumulation, Phytoabsorption or Phytosequestration): this involves the absorption of contaminants by roots followed by translocation and accumulation in the aerial parts. It is mainly applied to metals (Cd, Ni, Cu, Zn, Pb) but can also be used for other elements (Se, As) and organic compounds. This technique preferentially uses hyperaccumulator plants, that have the ability to store high concentrations of specific metals in their aerial parts (0.01% to 1% dry weight, depending on the metal). Elsholtzia splendens, Alyssum bertolonii, Thlaspi caerulescens and Pteris vittata are known examples of hyperaccumulator plants for Cu, Ni, Zn/Cd and As, respectively [3,19-26].
\n\t\t\t\t\t\tPhytofiltration: this uses plants to absorb, concentrate and/or precipitate contaminants, particularly heavy metals or radioactive elements, from an aqueous medium through their root system or other submerged organs. The plants are kept in a hydroponic system, whereby the effluents pass and are “filtered” by the roots (Rhizofiltration), or other organs that absorb and concentrate contaminants [13,27,28]. Plants with high root biomass, or high absorption surface, with more accumulation capacity (aquatic hyperaccumulators) and tolerance to contaminants achieve the best results. Promising examples include Helianthus annus, Brassica juncea, Phragmites australis, Fontinalis antipyretica and several species of Salix, Populus, Lemna and Callitriche [3,16,29-31].
\n\t\t\t\t\t\tRhizodegradation (Phytostimulation): growing roots promote the proliferation of degrading rhizosphere microorganisms which utilize exudates and metabolites of plants as a source of carbon and energy. In addition, plants may exude biodegrading enzymes themselves. The application of phytostimulation is limited to organic contaminants [3,27]. The microbial community in the rhizosphere is heterogeneous due to variable spatial distribution of nutrients, however species of the genus Pseudomonas are the predominant organisms associated with roots [13,32,33].
There are other strategies, which are considered categories of phytoremediation by some authors, but actually, they are mixed techniques or variations of the above mentioned strategies. These include:
\n\t\t\t\t\t\tHydraulic barriers: some large trees, particularly those with deep roots (e.g., Populus sp.), remove large quantities of groundwater during transpiration. Contaminants in this water are metabolized by plant enzymes, and vaporized together with water or simply sequestered in plant tissues [3,34].
\n\t\t\t\t\t\tVegetation covers: Herbs (usually grasses), eventually shrubs or trees, establish on landfills or tailings, are used to minimize the infiltration of rain water, and contain the spread of pollutants. The roots increase soil aeration thus, promoting biodegradation, evaporation and transpiration [7,35-37]. The difficulty of this technique is that tailings generally are not suitable for the development of plant roots. However, various investigations have been undertaken with the aim of developing processes of cultivation in tailings. For example a technique in which an organic soil composed of sawdust, plant remains, and some NPK-fertilizers is deposited on the surface was utilized by Hungarian agronomists (Biological Reclamation Process, BRP), [38]. The workers were able to obtain, at the end of a single biological cycle, 76 different plant species including cereals, shrubs, fruit trees and even large trees like oaks and pines.
\n\t\t\t\t\t\tConstructed wetlands: these are ecosystems consisting of organic soils, microorganisms, algae and vascular aquatic plants in areas where the water level is at/near the surface, at least part of the year. All the components work together in the treatment of effluents, through the combined actions of filtration, ion exchange, adsorption and precipitation [27,39,40]. It is the oldest method of wastewater treatment and is not regarded as proper phytoremediation, since it is based on the contributions of the entire system [3,41]. Good cleaning efficiency, low cost of construction along with easy operation and maintenance are the main advantages. It is widely applied in the treatment of domestic, agricultural and industrial waste water, but has proved to be suitable also for treating acid mine drainages [42-45].
\n\t\t\t\t\t\tPhytodesalination: it is a recently reported [13,46] emerging technique that utilizes halophytes to remove excess salts from saline soils. The potential of Suaeda maritima and Sesuvium portulacastrum in removal and accumulation of NaCl, from highly saline soils, has been demonstrated [47]. Although it has its peculiarities, this technique is a modality of phytoextraction.
Phytoremediation offers several advantages, but also some disadvantages, which should be considered when seeking to apply this technology (Table 1). If low cost is an advantage, the time necessary to observe the results can be long. The pollutant concentration and the presence of other toxins should be within the tolerance limits of the plant to be used. Selecting plants with the efficiency for remediating varied contaminants simultaneously is not easy. These limitations and the possibility of these plants entering in the food chains, should be taken into account when applying this technology.
\n\t\t\t\tAdvantages\n\t\t\t | \n\t\t\t\n\t\t\t\tLimitations\n\t\t\t | \n\t\t
\n\t\t\t\tIn situ and passive technique | \n\t\t\tLimited to shallow soils or where contamination is localized to the surface (< 5 m) | \n\t\t
Uses solar energy and is low cost | \n\t\t\tStill under development and therefore not accepted by many regulatory agencies | \n\t\t
Has reduced environmental impact and contributes to the landscape improvement | \n\t\t\tThere is little knowledge of farming, genetics, reproduction and diseases of phytoremediating plants | \n\t\t
High acceptance by the public | \n\t\t\tMetal concentrations in the soil can be toxic and lethal to plants | \n\t\t
Provides habitat for animal life | \n\t\t\tGenerally, plants are selective in metal remediation | \n\t\t
Reduction in dispersal of dust and contaminants by wind | \n\t\t\tTreatment slower than the traditional physico-chemical techniques | \n\t\t
Reduction of surface runoff | \n\t\t\tContamination may spread through the food chain if accumulator plants are ingested by animals | \n\t\t
Reduction of leaching and mobilization of contaminants in soil | \n\t\t\tEfficient phytoremediating plants may not adapt to climatic and environmental conditions at contaminated sites | \n\t\t
Harvesting of the plants or organs that have accumulated metals is easy to accomplish with existing technology | \n\t\t\tIf the plants release compounds to increase the mobility of the metals, these can be leached into groundwater | \n\t\t
The harvested biomass can be economically valuable | \n\t\t\tThe area to be decontaminated must be large enough to allow application of cultivation techniques | \n\t\t
Plant process more easily controlled than those of microorganisms | \n\t\t\tToxicity and bioavailability of degradation products remain largely unknown | \n\t\t
Phytoextraction and phytostabilization are the two techniques most useful for phytoremediation of metal and metalloid contaminated soils. Phytoextraction has been widely studied, mainly due to the potential for high efficiency and possible economic value (in metal recovery, energy production) [3,23,24,48,50,51]. Preferably, plants used in phytoextraction should present, among others, the following characteristics [13,23,52,53]:
tolerance to high concentrations of metals;
accumulate high concentrations in their aerial tissues;
rapid growth;
high biomass production;
profuse root system;
easy to cultivate and harvest.
Phytoextraction can only be considered effective if the accumulated contaminant is subsequently removed through harvesting (Figure 2). If most of the captured heavy metals are translocated to shoots, traditional farming methods can be used for harvesting. It is important to harvest the plants before leaf-fall or death and decomposition to ensure that contaminants do not disperse or return to the soil [20].
Schematic representation of phytoextraction of metals from soil.
After harvesting, biomass may be processed for extraction and recovery of metals (phytomining). The commercial value of metals such as Ni, Zn, Cu or Co may encourage the phytoremediation process. Alternatively, thermal, physical, chemical or microbiological processes can be used to reduce the volume/ weight of biomass. In the case of incineration of plants the energy produced represents an economic opportunity, and the ash can be further processed for extraction of metals. However, this process must be very careful, given the possible chemical elements accumulated, to prevent any dispersion mechanisms of contaminants.
According to McGrath and Zhao [22], phytoextraction efficiency is determined by two key factors: the ability to hyperaccumulate metals and the biomass production. Therefore, if these factors influence the phytoextraction, they can be optimized to improve the phytoremediation process. One possibility is the addition of chemical agents into the soil in order to increase the bioavailability of metals and their root uptake [54,55]. This form of assisted phytoremediation (or induced phytoremediation) has shown great potential and has been widely studied (Figure 3).
Schematic representation of the processes of natural (A) and assisted (B) phytoextraction.
Although hyperaccumulators are phytoextractors par excellence, usually they are low biomass producers. Thus, it is generally accepted that plants with a significant biomass production capacity can compensate their relatively lower metal accumulation capacity, to an extent where the amount of metal removed can be higher [51].
Phytoextraction potential can be estimated by calculation of bioconcentration factor (or biological absorption coefficient) and translocation factor [51,56]. The bioconcentration factor (BCF), which is defined as the ratio of the total concentration of element in the harvested plant tissue (Cplant) to its concentration in the soil in which the plant was growing (Csoil), is calculated as follows:
Translocation factor (TF), defined as the ratio of the total concentration of elements in the aerial parts of the plant (Cshoot) to the concentration in the root (Croot), is calculated as follows:
The commercial efficiency of phytoextraction can be estimated by the rate of metal accumulation and biomass production. Multiplying the rate of accumulation (metal (g)/plant tissue (kg)) by the growth rate (plant tissue (kg)/hectare/year), gives the metal removal value (g/kg of metal per hectare and per year) [3,19,54,57]. This rate of removal or extraction should reach several hundred, or at least 1 kg/ha/year, for the species to be commercially useful, and even then, the remediation process may take from 15 to 20 years [3].
Some soils are so heavily contaminated that removal of metals using plants would take an unrealistic amount of time. The normal practice is to choose drought-resistant fast-growing crops or fodder which can grow in metal-contaminated and nutrient-deficient soils.
In contrast to phytoextraction, phytostabilization aims at reducing the mobility of contaminants in the soil. In this technique, contaminated soil is covered by vegetation tolerant to high concentrations of toxic elements, limiting the soil erosion and leaching of contaminants in to groundwater. Mobility of contaminants can be reduced by surface adsorption/accumulation in roots as well as their precipitation in rhizosphere by induced changes in pH or by oxidation of the root environment [3,12,58]. For example, the immobilization of arsenic in iron plates in the rhizosphere of salt marsh plants [58,59]. Phytostabilization can also be promoted by plant species with the capacity to exude high amounts of chelating substances. These substances lead to immobilization of contaminants by preventing their absorption, while simultaneously reducing their mobility in soil. Thus, plants with phytostabilization potential can be of great value for the revegetation of mine tailings and contaminated areas [58,60].
It is possible to find a wide variety of plant species that can colonize areas highly polluted with heavy metals and metalloids, such as mine tailings or soils degraded and contaminated by mining/industrial activities. These are referred to as metallophyte and pseudometallophyte species.
Metallophytes are endemic plant species of natural mineralized soils and, therefore, have developed physiological mechanisms of resistance and tolerance to survive on substrates with high metal levels [61,62]. Since metallophytes, in general, and hyperaccumulators, in particular, are relatively rare and usually produce reduced biomass, the study of pseudometallophytes, indigenous species of contaminated soils, is of great value. Pseudometallophyte species (or facultative metallophytes) aren’t specialized in metalliferous soils and have a more extensive distribution, but, due to selective pressure, are capable to survive in metalliferous soils [63-65]. Thus, the high pressure of metalliferous soils (natural or contaminated by human action) allows the selection of populations of common species, with higher tolerance than other populations of the same species. Therefore, their capacity of adaptation to these environments and, eventually, of accumulation of metals and metalloids, can be very interesting with a view to their use, for example, in ecological restoration, phytoremediation and bioindication actions.
In recent decades many studies have been conducted in contaminated mining and industrial areas and in natural metalliferous soils [35,51,58,66-78] in order to inventory and screen the indigenous species and evaluate their potential for phytoremediation of contaminated soils.
Several studies to survey the indigenous plant species of diverse contaminated areas and evaluate their potential for phytoremediation have been performed in Portugal [79-93]. The authors have undertaken studies to evaluate the phytotechnological potential (phytoremediation, phytomining, bioindication, biogeochemical prospecting) of native flora of soils enriched with metals and metalloids, in distinct abandoned mining areas of tin/tungsten (Sn/W), copper (Cu), lead (Pb), uranium (U), and chromium (Cr) and the results are presented in this chapter.
In the old mining areas studied, several line transects were made in mineralized and non-mineralized zones as well as tailings. Soils and plants were collected at 20 m intervals along the line transects (0, 20, 40 m, etc.) in circle of ≅2 m radius. At each location four random partial soil samples weighing 0.5 kg each were collected from 0 to 20 cm depth and mixed to obtain one composite sample to save time and costs. These were oven-dried at a constant temperature, manually homogenized and quartered. Two equivalent fractions were obtained from each quartered sample. One was used for the determination of pH, and the other for chemical analysis. The samples for chemical analysis were sieved using a 2 mm mesh sieve to remove plant matter and subsequently screened to pass through a 250 µm screen. Samples were also obtained from all species of plants whenever found growing within the 2 m radius of each sampling point. The plant sample focused on the aerial parts, taking into consideration similar maturity of the plants and the proportionality of the different types of tissues, or the separation of different types of tissues (leaves and stems) in some species. In the laboratory, the vegetal material was washed thoroughly, first in running water followed by distilled water, and then dried in a glasshouse. When dry, the material was milled into a homogenous powder. Soil pH was determined in water extract (1:2.5 v/v). The soil and plant samples were acid-digested for elemental analysis. Analytical methods included colorimetry for W, atomic absorption spectrophotometry (AAS, Perkin-Elmer, 2380) for Ag, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn and hydride generation system (HGS) for As and Sb. Fluorometry (Fluorat-02-2M analyzer, Lumex) was the methodology that was adopted for the determination of the U content in the plant and soil samples. Data quality control was performed by inserting triplicate samples into each batch. Certified references materials were also used.
The studied areas included several abandoned Sn/W mines (Sarzedas mine, Fragas do Cavalo mine, Tarouca mine, Vale das Gatas mine, Adoria mine, Ervedosa mine, Regoufe mine, and Rio de Frades mine). Results obtained from Sarzedas (Central Portugal) and Vale das Gatas mines (Northern Portugal) are presented.
A summary of trace element data in soil from the Sarzedas mine is shown in Table 2. Among the elements present in the soils, Ag, As, Pb, Sb and W show the most relevant anomalies. Soil pH was negatively correlated to mineralization. Low pH values observed near the mineralized area can be explained by the presence of sulfides in the mineralization [84]. High levels of sulfides, in particular pyrite and arsenopyrite that are easily weathered, favors the dissolution of toxic elements, allowing higher dispersion and bioavailability.
\n\t\t\t | \n\t\t\t\tRange\n\t\t\t | \n\t\t\t\n\t\t\t\tMean\n\t\t\t | \n\t\t\t\n\t\t\t\tMedian\n\t\t\t | \n\t\t\t\n\t\t\t\tStandard deviation\n\t\t\t | \n\t\t
pH | \n\t\t\t3.3 – 5.2 | \n\t\t\t4.7 | \n\t\t\t4.8 | \n\t\t\t0.5 | \n\t\t
Ag | \n\t\t\t0.69 – 1.91 | \n\t\t\t0.98 | \n\t\t\t0.92 | \n\t\t\t0.32 | \n\t\t
As | \n\t\t\t11.1 – 651 | \n\t\t\t76.3 | \n\t\t\t19.9 | \n\t\t\t181 | \n\t\t
Co | \n\t\t\t5.40 – 14.9 | \n\t\t\t8.80 | \n\t\t\t8.41 | \n\t\t\t2.60 | \n\t\t
Cr | \n\t\t\t50.7 – 129 | \n\t\t\t96.5 | \n\t\t\t100 | \n\t\t\t26.3 | \n\t\t
Cu | \n\t\t\t15.5 – 78.2 | \n\t\t\t40.7 | \n\t\t\t35.1 | \n\t\t\t21.1 | \n\t\t
Fe | \n\t\t\t21,881 – 58,644 | \n\t\t\t39,981 | \n\t\t\t37,356 | \n\t\t\t12,883 | \n\t\t
Mn | \n\t\t\t22.0 – 92.0 | \n\t\t\t50.0 | \n\t\t\t47.0 | \n\t\t\t22.0 | \n\t\t
Ni | \n\t\t\t11.2 – 52.5 | \n\t\t\t21.8 | \n\t\t\t19.7 | \n\t\t\t10.2 | \n\t\t
Pb | \n\t\t\t35.7 – 417 | \n\t\t\t85.4 | \n\t\t\t53.9 | \n\t\t\t106 | \n\t\t
Sb | \n\t\t\t30.5 – 5,986 | \n\t\t\t663 | \n\t\t\t87.8 | \n\t\t\t1,689 | \n\t\t
W | \n\t\t\t0.80 – 684 | \n\t\t\t663 | \n\t\t\t2.90 | \n\t\t\t52.3 | \n\t\t
Zn | \n\t\t\t29.0 – 127 | \n\t\t\t58.8 | \n\t\t\t53.3 | \n\t\t\t24.3 | \n\t\t
Trace elements content (mg/kg) and pH of soil samples (N=24, Sarzedas mine).
In the flora of Sarzedas mine area, As was accumulated in aerial tissues of Pinus pinaster and Digitalis purpurea. Therefore, these species are suited for recognizing the anomaly. High accumulation of As was present in leaves (Figure 4), and it increased in the older tissues. This translocation is a common mechanism in plants to avoid toxicity in young leaves as their metabolic activity is higher [84]. Digitalis purpurea also accumulated substantial amount of Sb (Figure 5), indicating its tolerance to this element, although the assimilation occured at low concentrations in the soil. Species that are capable of accumulating W are D. purpurea, Cistus ladanifer, P. pinaster, Calluna vulgaris and Helichrysum stoechas (Figure 6).
Accumulation of As (mg/kg DW) in plant species of the Sarzedas mining area.
Accumulation of Sb (mg/kg DW) in plant species of the Sarzedas mining area.
Accumulation of W (mg/kg DW) in plant species of the Sarzedas mining area.
It was concluded that the species and organs best suited for biogeochemical prospecting and/or with potential for mine restoration in the Sarzedas mine area are by order of importance: 1) As: old needles of P. pinaster, aerial tissues of C. vulgaris, Chamaespartium tridentatum, leaves of C. ladanifer, Erica umbellata and Quercus ilex subsp. ballota; 2) Sb: D. purpurea, E. umbellata, stems of C. ladanifer, C. vulgaris, C. tridentatum and stems of P. pinaster; 3) W: D. purpurea, C. tridentatum, old stems and needles of P. pinaster, stem and leaves of C. ladanifer, E. umbellata and stems and leaves of Q. ilex [84].
\n\t\t\t | \n\t\t\t\tRange\n\t\t\t | \n\t\t\t\n\t\t\t\tMean\n\t\t\t | \n\t\t\t\n\t\t\t\tMedian\n\t\t\t | \n\t\t\t\n\t\t\t\tStandard deviation\n\t\t\t | \n\t\t
pH | \n\t\t\t3.5 – 6.3 | \n\t\t\t5.0 | \n\t\t\t5.0 | \n\t\t\t0.8 | \n\t\t
As | \n\t\t\t26.7 – 5,770 | \n\t\t\t446 | \n\t\t\t56.7 | \n\t\t\t1,178 | \n\t\t
Cu | \n\t\t\t11.7 – 352 | \n\t\t\t88.0 | \n\t\t\t29.0 | \n\t\t\t101 | \n\t\t
Fe | \n\t\t\t18,482 – 60,100 | \n\t\t\t33,039 | \n\t\t\t29,443 | \n\t\t\t12,463 | \n\t\t
Mn | \n\t\t\t103 – 898 | \n\t\t\t336 | \n\t\t\t167 | \n\t\t\t248 | \n\t\t
Ni | \n\t\t\t11.6 – 61.2 | \n\t\t\t30.6 | \n\t\t\t23.6 | \n\t\t\t15.1 | \n\t\t
Pb | \n\t\t\t55.4 – 6,299 | \n\t\t\t499 | \n\t\t\t102 | \n\t\t\t1,285 | \n\t\t
Zn | \n\t\t\t63.1 – 469 | \n\t\t\t180 | \n\t\t\t125 | \n\t\t\t112 | \n\t\t
W | \n\t\t\t2.00 – 636 | \n\t\t\t73.8 | \n\t\t\t10.6 | \n\t\t\t162 | \n\t\t
Trace elements content (mg/kg) and pH of soil samples (N=69, V. Gatas mine).
Very high maximum values for Pb (6,299 mg/kg), As (5,770 mg/kg) and W (636 mg/kg) were observed at the Vale das Gatas mine (Table 3). The Cu-Mn-W-As-Pb-Zn association, which reflects the presence of mineralised veins in the area, is inversely correlated with pH [93]. In general, the content variations in plant materials were strongly related to the content variations in soils. It has also been verified that in contaminated locations or tailings, the concentration of metals in plant tissues is high due to the high metal concentrations in the soil.
The leaves of Agrostis castellana and Holcus lanatus reflect the Cu, Pb and Ni pedogeochemical anomalies. The aerial parts of Pteridium\n\t\t\t\t\t\t\taquilinum and Juncus effusus seem to be indicative of Zn anomalies in the soil [94]. Holcus lanatus and A. castellana were the main accumulators of As (Figure 7), Cu (Figure 8), Fe (Figure 9) and Pb (Figure 10) and good accumulators of Zn (Figure 11). Pteridium aquilinum was a good accumulator of As, Pb and Zn (Figures 7, 10, 11). Juncus effusus appeared to be a Zn accumulator (Figure 11).
Accumulation of As (mg/kg DW) in plant species of the V. Gatas mining area.
Accumulation of Cu (mg/kg DW) in plant species of the V. Gatas mining area.
Accumulation of Fe (mg/kg DW) in plant species of the V. Gatas mining area.
Accumulation of Pb (mg/kg DW) in plant species of the V. Gatas mining area.
Accumulation of Zn (mg/kg DW) in plant species of the V. Gatas mining area.
The P. pinaster trees growing on the tailings and contaminated soils of Vale das Gatas mine accumulated the studied elements in quantities greater than observed in plants of the areas representative of the local geochemical background. These values were also higher than those typically observed in this species.
In the P. pinaster samples from tailings and contaminated soil locations, the older needles (2- and 3-years-old) show a tendency to accumulate higher concentrations of As, Fe, Zn, Pb and W while Ni and Cu were preferentially accumulated in young needles and stems (1-year-old) [93]. This allowed the authors to conclude that the metal/metalloid concentrations of elements in plants depend as much on the plant organ as on its age and in biogeochemical studies, it is important not to mix foliar and woody material in the same sample. The species showed a great variability in the accumulation behaviour of As, Fe, Mn, Cu, Zn, Pb, Ni, and W with the age of the organ. Thus, the 1-year-old needles and stems accumulated higher levels of Cu (Figure 8) and Ni (Figure 12). While the older needles accumulated higher levels of As, Fe, Pb, Zn and W (Figures 7, 9, 10, 11 and 13). The 2-years-old stems may also be appropriate samples to detect higher levels of Fe, Zn and Pb.
Accumulation of Ni (mg/kg DW) in plant species of the V. Gatas mining area.
Accumulation of W (mg/kg DW) in plant species of the V. Gatas mining area.
The São Domingos mine (abandoned in 1966) located in south-east Portugal is also included in this study. This is one of the historical mining centres, known for its activity since pre-Roman times, with extraction of gold, silver and copper [95] though copper production was the highlight.
A summary of soil trace element data is presented in Table 4. High levels of As, Cu, Pb and Zn were recorded in the soils. Copper concentration in soils reached up to 1,829 mg/kg as a result of the former activities at the site (copper smelter). Maximum concentration of As in soils was very high, reaching 1,291 mg/kg. The concentration of Pb in the soil was also very high, 2,694 mg/kg as the average value registered. The average Zn concentration in soils was of 218 mg/kg but it could reach 714 mg/kg, a level that can be extremely toxic for plants. Cobalt and Cr concentrations in soils were normally low, ranging from 20.1 to 54.3 mg/kg for Co and 5.1 to 84.6 mg/kg for Cr. Nickel and Ag were also low, varying from 27.2–52.9 mg/kg and 2.5–16.6 mg/kg, respectively.
\n\t\t\t | Range | \n\t\t\tMean | \n\t\t\tMedian | \n\t\t\tStandard deviation | \n\t\t
pH | \n\t\t\t4.0 – 6.7 | \n\t\t\t5.1 | \n\t\t\t5.1 | \n\t\t\t0.6 | \n\t\t
Ag | \n\t\t\t2.50 – 16.6 | \n\t\t\t7.50 | \n\t\t\t7.00 | \n\t\t\t3.60 | \n\t\t
As | \n\t\t\t37.2 – 1291 | \n\t\t\t393 | \n\t\t\t353 | \n\t\t\t324 | \n\t\t
Co | \n\t\t\t20.1 – 54.3 | \n\t\t\t31.0 | \n\t\t\t29.4 | \n\t\t\t8.40 | \n\t\t
Cr | \n\t\t\t5.10 – 84.6 | \n\t\t\t26.5 | \n\t\t\t8.30 | \n\t\t\t31.7 | \n\t\t
Cu | \n\t\t\t87.3 – 1,829 | \n\t\t\t553 | \n\t\t\t444 | \n\t\t\t443 | \n\t\t
Ni | \n\t\t\t27.2 – 52.9 | \n\t\t\t42.2 | \n\t\t\t43.9 | \n\t\t\t6.60 | \n\t\t
Pb | \n\t\t\t234 – 12,218 | \n\t\t\t2,694 | \n\t\t\t2,355 | \n\t\t\t2,345 | \n\t\t
Zn | \n\t\t\t104 – 714 | \n\t\t\t218 | \n\t\t\t163 | \n\t\t\t145 | \n\t\t
Trace elements content (mg/kg) and pH of soil samples (N=21, S. Domingos mine).
In plants, Pb concentration was rather high for some species, varying from 2.9 to 84.9 mg/kg dry weight (DW) (Figure 14). Semi-aquatic species sampled in the mining area, Juncus conglomeratus and Scirpus holoschoenus, showed high accumulation of Pb in plant tissues. Lead above 20 mg/kg DW was found in leaves of two species of Cistus, typical Mediterranean shrubs known for their tolerance to drought and low nutrients availability. Arsenic concentration in plant tissues ranged from 0.3 to 23.5 mg/kg DW. Maximum As was recorded in J. conglomeratus, Thymus mastichina, J. effusus and S. holoschoenus [82]. Semi-aquatic species from the Juncaceae family showed the highest content of both metals. Copper concentration in plant tissues ranged from 3.60 to 28.9 mg/kg DW (Figure 15). These Cu values are within the range considered normal for plants [96]. The species Cistus monspeliensis and Daphne gnidium showed the highest Zn concentrations [82]. A few trees, Eucalyptus, Quercus and Pinus species, were found in the contaminated area showing accumulation of different metals in the aboveground tissues. Due to their high biomass, they can be very effective for metals phytoextraction and phytostabilization especially when established in the less contaminated soils on the peripheral zone of the study area [82].
Accumulation of Pb (mg/kg DW) in plant species of the S. Domingos mining area.
Accumulation of Cu (mg/kg DW) in plant species of the S. Domingos mining area.
The Barbadalhos mine is an abandoned Pb mine in Central Portugal. It was exploited for Pb by underground mining from 1887 till the 1940s. The concentrated ore was smelted on site. As per the usual practice at the time, tailings were deposited on the ground.
Metal concentrations in soil are shown in Table 5. Lead concentration in soils reached 9,331 mg/kg while the average value was 928 mg/kg; obviously due to mining of galena at the site. In soils from mineralized zone, the mean Pb concentration (2,380 mg/kg) was nearly 9 times the threshold for industrial soils suggested by Canadian Environmental Quality Guidelines [97].
\n\t\t\t | \n\t\t\t\tRange\n\t\t\t | \n\t\t\t\n\t\t\t\tMean\n\t\t\t | \n\t\t\t\n\t\t\t\tMedian\n\t\t\t | \n\t\t\t\n\t\t\t\tStandard deviation\n\t\t\t | \n\t\t
pH | \n\t\t\t3,6 – 6.4 | \n\t\t\t4.7 | \n\t\t\t4.6 | \n\t\t\t0.5 | \n\t\t
Ag | \n\t\t\t0.71 – 13.0 | \n\t\t\t1.71 | \n\t\t\t1.06 | \n\t\t\t2.03 | \n\t\t
As | \n\t\t\t2.77 – 208 | \n\t\t\t16.9 | \n\t\t\t8.07 | \n\t\t\t31.7 | \n\t\t
Co | \n\t\t\t3.74 – 50.5 | \n\t\t\t20.1 | \n\t\t\t16.7 | \n\t\t\t12.4 | \n\t\t
Cr | \n\t\t\t61.3 – 196 | \n\t\t\t89.0 | \n\t\t\t85.7 | \n\t\t\t22.1 | \n\t\t
Cu | \n\t\t\t21.4 – 193 | \n\t\t\t41.7 | \n\t\t\t34.5 | \n\t\t\t27.9 | \n\t\t
Fe | \n\t\t\t24,145 – 98,510 | \n\t\t\t40,283 | \n\t\t\t38,497 | \n\t\t\t13,751 | \n\t\t
Mn | \n\t\t\t44.4 – 2,224 | \n\t\t\t596 | \n\t\t\t381 | \n\t\t\t588 | \n\t\t
Ni | \n\t\t\t7.68 – 87.0 | \n\t\t\t30.5 | \n\t\t\t28.1 | \n\t\t\t12.2 | \n\t\t
Pb | \n\t\t\t24.4 – 9,331 | \n\t\t\t928 | \n\t\t\t68.8 | \n\t\t\t2,119 | \n\t\t
Zn | \n\t\t\t30.4 – 517 | \n\t\t\t134 | \n\t\t\t90.3 | \n\t\t\t109 | \n\t\t
Trace elements content (mg/kg) and pH of soil samples (N=45, Barbadalhos mine).
Samples from 49 species of the native flora were investigated at this site. Individual elements and species displayed different trends of accumulation. All plants collected along mineralized zone accumulated eight metals (Ag, Co, Cr, Cu, Fe, Ni, Pb, and Zn) but many plants from non-mineralized zone accumulated only five metals (Ag, Cu, Fe, Pb, and Zn). A few however did accumulate the remaining three (Co, Cr, and Ni); bringing the count of metals accumulated at par with those of mineralized zone [92].
Most plants were seen to be tolerant of soil Pb concentrations. In mineralized zone, Pb concentrations in plants ranged from 1.11 to 548 mg/kg DW. This is far above the 100 – 400 mg Pb/kg content considered toxic for most plants [98]. Significant accumulation of Pb was seen in Cistus salvifolius (548 mg/kg), Lonicera periclymenum (318 mg/kg), Anarrhinum bellidifolium, Phytolacca americana, Digitalis purpurea, Mentha suaveolens (255 – 217 mg/kg) [listed in decreasing order] (Figure 16). Pteridophytes like Polystichum setiferum, Pteridium aquilinum, and Asplenium onopteris also showed 117 – 251 mg/kg Pb in aerial parts. In plants from non-mineralized zone, Pb content was not significant ranging from 0.94 to 11.6 mg/kg.
Though at first glance maximum Pb content observed in trees like Acacia dealbata (84 mg/kg: leaves), Olea europaea (62 mg/kg: twigs), and Quercus suber (58 mg/kg: twigs) from mineralized zone is not very impressive compared to that of smaller plants mentioned above, nevertheless these trees can be very effective due to their higher biomass. When combined with the hardy nature, biomass and abundance of this species, the moderate accumulation indicates immense potential for phytoextraction of Pb in the area [92].
In mineralized zone, Zn concentrations in plants reached 1,020 mg/kg in D. purpurea. And ranged from 262 to 887 mg/kg in L. periclymenum, P. americana, Solanum nigrum, P. setiferum, M. suaveolens, Viola riviniana, and A. bellidifolium [listed in decreasing order] [92].
Accumulation of Pb (mg/kg DW) in plant species of the Barbadalhos mining area.
The old U mine of Sevilha (Central Portugal) is one of several small mines exploited by ENU (Portuguese Uranium Company). After the removal of the main ore body, the site was filled with the mine wastes and a reclamation process was initiated. This action was somewhat unsuccessful because the selected allochthonous plant species (Lupinus sp.) did not survive.
Current U soil contamination on the Sevilha mine ranges from 8 to 560 mg/kg [99]. Species of Compositae and Ericaceae (among the most abundant families of terrestrial plants) accumulated highest U concentrations (Figure 17). Among Compositae members, an average of 4.91 mg/kg DW and a maximum of 13.1 mg/kg DW was found in Helichrysum stoechas and an average of 4.07 mg/kg DW and a maximum of 10.5 mg/kg DW was recorded in Hypochaeris radicata (Figure 17). In Erica umbellata an average of 1.70 mg/kg DW and a maximum of 7.50 mg/kg DW were obtained (Figure 17). Even though the concentrations obtained in the latter are not high, it is particularly interesting because it has a high bio-productivity. This accumulation potential might be intensified if uptake enhancement strategies, such as addition of citric acid, are adopted. A restoration program can be applied to the soils of Sevilha mine by adopting revegetation with endemic species allied to a process of continuous phytoremediation that avoids dispersion of U into the streamlets.
Accumulation of U (mg/kg DW) in plant species of the Sevilha mining area.
Even though the soils in this mine are not highly contaminated, the lixiviation of refilling materials has been responsible for the dispersion of U into ground and superficial water bodies. These waters are being used for subsistence agriculture and, therefore, the risk of contamination spreading to humans can be acute, due to food chain accumulation [99]. The plant survey revealed that some of the native plant species are well adapted to U contamination in soils, therefore, they are metallotolerants. Their phytoremediation potential has to be evaluated. Dispersion of U into the streamlets can be minimized by a strategic combination of terrestrial and aquatic plant phyto-systems. Revegetation with Helichrysum stoechas, Hypochaeris radicata and Erica umbellata will allow fixation of U in the plants and a consequent reduction in its dispersion. This site can be an excellent prototype for the restoration of other mines in Portugal where levels of contamination are a matter of concern.
The abandoned mining area of Pingarela in North-east Portugal has serpentine soils and associated flora. These soils are disproportionately rich in trace elements like Ni, Cr, Co and poor in Ca. Serpentine outcrops have been referred to as barrens because they are often sparsely vegetated and extremely poor in essential nutrients, hence not of much agricultural value. Serpentine ecosystems can generally be distinguished by their grey-green or reddish rocky soils (soils are very thin), and shrubby or stunted vegetation with plants having small leathery leaves.
Plant species found on serpentine soils can be divided into two groups: (a) serpentine-tolerant or serpentine-facultative plants, which are able to survive on serpentine but grow better elsewhere; (b) serpentinicolous, serpentine-endemic or serpentine-obligate plants, which grow exclusively on serpentine soils and are not found on other substrates [83,100]. Both these groups include species with different efficiencies to uptake or exclude a variety of metals. Serpentinophytes often experience drought, nutrient stress and excessive exposure to heavy metal and high light intensity. This means there is less substrate in which nutrients and water can be held and made available to plants.
An area of ~8,000 ha in north-east Portugal is serpentinized with characteristic geology and flora. The serpentine plant community and respective soils were analyzed [83] to examine the trace metal budget in different tissues of the plants exhibiting resistance to trace metals. 135 plant species belonging to 39 families and respective soils were analyzed for total Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn. Heavy metal concentrations recorded in sampled soils are shown in Table 6. The high contents of Ni and Cr obtained were to be expected, considering the geochemistry of the sampling site. However, the high variability of Cr, Ni, Fe and Mn in the soils is noteworthy.
\n\t\t\t | \n\t\t\t\tRange\n\t\t\t | \n\t\t\t\n\t\t\t\tMean\n\t\t\t | \n\t\t\t\n\t\t\t\tMedian\n\t\t\t | \n\t\t\t\n\t\t\t\tStandard deviation\n\t\t\t | \n\t\t
pH | \n\t\t\t4.9 – 9.3 | \n\t\t\t6.7 | \n\t\t\t6.7 | \n\t\t\t0.6 | \n\t\t
Co | \n\t\t\t56.0 – 151 | \n\t\t\t82.3 | \n\t\t\t81.1 | \n\t\t\t18.5 | \n\t\t
Cr | \n\t\t\t200 – 6,822 | \n\t\t\t1,622 | \n\t\t\t1,410 | \n\t\t\t1,064 | \n\t\t
Cu | \n\t\t\t30.8 – 221 | \n\t\t\t101 | \n\t\t\t99.3 | \n\t\t\t34.7 | \n\t\t
Fe | \n\t\t\t95.0 – 110,418 | \n\t\t\t82,950 | \n\t\t\t84,711 | \n\t\t\t14,502 | \n\t\t
Mn | \n\t\t\t1,007 – 1,835 | \n\t\t\t1,389 | \n\t\t\t1,363 | \n\t\t\t175 | \n\t\t
Ni | \n\t\t\t102 – 2,295 | \n\t\t\t918 | \n\t\t\t883 | \n\t\t\t464 | \n\t\t
Pb | \n\t\t\t18.5 – 46.6 | \n\t\t\t29.2 | \n\t\t\t29.1 | \n\t\t\t5.78 | \n\t\t
Zn | \n\t\t\t63.0 – 242 | \n\t\t\t110 | \n\t\t\t112 | \n\t\t\t24.8 | \n\t\t
Trace element content (mg/kg) and pH of serpentine soil samples (N=74, Pingarela mine).
The Ni hyperaccumulating endemic of this region is Alyssum serpyllifolium subsp. lusitanicum, which concentrated 38,105 mg Ni/kg DW in the aboveground tissues (Figure 18). Bromus hordeaceus with 1,467 mg Ni/kg DW and Linaria spartea with 492 mg Ni/kg DW in the aerial parts, also showed high concentration of Ni. Four other taxa viz.—Plantago radicata, Ulmus procera, Lavandula stoechas and Cistus salvifolius showed more than 100 mg Ni/kg DW (Figure 18).
Chromium has low solubility in the serpentine soil solution due to the relatively high pH values of these soils [83]. This is reflected in the low uptake of this element by plants, which in general did not exceed 40 mg/kg. However, concentrations of 707 mg Cr/kg DW were reported in the above ground parts of L. spartea (Figure 19). Alyssum serpyllifolium also presented high content of Cr, reaching a maximum of 130 mg Cr/kg DW. Ulmus procera showed a content of 173 mg Cr/kg DW in the twigs.
Accumulation of Ni (mg/kg DW) in serpentine plant species of the Pingarela mining area.
Accumulation of Cr (mg/kg DW) in serpentine plant species of the Pingarela mining area.
Although leaves of serpentine plants show 10 times higher Co levels than those of plants growing on non-serpentine soils, the absolute concentrations are only about 10 mg/kg DW in most species. In this study highest accumulation of Co was found in the aboveground tissues of A. serpyllifolium with 145 mg Co/kg DW and L. spartea with 63.2 mg Co/kg DW [83].
The physico-chemical properties of the metalliferous or metal-contaminated soils tend to inhibit soil-forming processes and plant growth. In addition to elevated metal/metalloid concentrations, other adverse factors included absence of topsoil, erosion, drought, compaction, wide temperature fluctuations, absence of soil-forming fine materials and shortage of essential nutrients [84,101]. Degraded soils of mines usually have low concentrations of important nutrients, like N, P and K [102]. Toxic metals can also adversely affect the number, diversity and activity of soil organisms, inhibiting soil organic matter decomposition and N mineralization processes. The chemical form of the potential toxic metal, the presence of other chemicals which may aggravate or attenuate metal toxicity, the prevailing pH and the poor nutrient status of contaminated soil affects the way in which plants respond to it. Substrate pH affects plant growth mainly through its effect on the solubility of chemicals, including toxic metals and nutrients.
Metal toxicity issues do not generally arise in the case of native flora, considering that native plants become adapted over time to the locally elevated metal levels [76,103]. Native plants may be better phytoremediators for contaminated lands than the known metal hyperaccumulators because these are generally slow growing with shallow root systems and low biomass. Plants tolerant to toxic metals and low nutrient status with a high rate of growth and biomass are the ideal species to remediate degraded soils and habitats like those around mines. The native flora displayed its ability to withstand high concentrations of heavy metals in the soil. Some species also displayed variable accumulation patterns for metals at different soil concentrations. This variation was also observed in different parts of the same plant suggesting that full consideration of plant–soil interactions should be taken into account when choosing plant species for developing and utilizing methods such as phytoremediation.
Indigenous plant species growing on tailings and contaminated soils show tolerance to imposed stress conditions (metal-contamination and nutrient deficiency) and can fulfill the objectives of stabilization, pollution attenuation and visual improvement. Besides, these species are drought-resistant and some even exhibit high biomass and bioproductivity. In fact, the constraints related to plant establishment and amendment of the physical–chemical properties of the metalliferous soils depends upon the choice of appropriate plant species. Hence, the plant community tolerant to toxic trace elements plays a major role in remediation of degraded mine soils.
The existing natural plant cover at abandoned mining sites can be increased manifold by wide-scale planting and maintenance of native species with higher metal accumulation potential for some years. Even dispersal of seeds obtained from plants on site is to be encouraged. Adding organic amendment is essential to facilitate the establishment and colonization of these “pioneer plants”. They can eventually modify the man-made habitat and render it more suitable for subsequent plant communities. Allowing native species to remediate soils is an attractive proposition since native wild species do not require frequent irrigation, fertilization, and pesticide treatments, while simultaneously a plant community comparable to that existing in the vicinity can be established.
Therefore, mine restoration could benefit from a broader perspective including different groups of plant species as they can perform distinct functional roles in the remediation process. The use of leguminous plants, for example, may enrich the nutrient content and the combined used of perennials and annuals can provide substantial inputs in terms of organic matter and nutrient recycling, thus contributing in distinct ways to the development of the soil [82,104]. This approach requires more information about plant communities growing on metal-contaminated soils in order to accurately determine their potential for remediation of polluted soils at abandoned mines. Ideal phytoremedial candidates can be screened out from the native flora and after assessing their individual requirements, suitable conditions/amendments can be created to develop them as good competitors with enhanced growth and proliferation than their counterparts growing on the same metal contaminated nutrient depleted soils.
Significant accumulation of heavy metals and metalloids in both soils and native wild flora suggests that metal contamination is a matter of great concern in the studied mining areas. The native flora displayed its ability to withstand high concentrations of heavy metals/metalloids in the soil. However, accumulation patterns of metals/metalloids in the plants tested differed. As metal concentrations in above ground parts were maintained at low levels, metal tolerance in most cases may mainly depend on their metal excluding ability. However, metal/metalloid concentrations higher than toxic level in some species like Agrostis castellana (for As, and Fe), Cistus ladanifer subsp. ladanifer (for Cr, and W), Cistus salvifolius (for Ni, and Pb), Digitalis purpurea subsp. purpurea (for Sb, W, and Zn), Helichrysum stoechas and Hypochaeris radicata (for U), Holcus lanatus (for As, Cu, and Fe), Lonicera periclymenum, Mentha suaveolens and Phytolacca americana (for Pb, and Zn), Pinus pinaster (for As, W, and Zn), Polystichum setiferum and Solanum nigrum subsp nigrum (for Zn), Pteridium aquilinum (for As), as well as the serpentine plant species Alyssum serpyllifolium subsp. lusitanicum, Lavandula stoechas subsp. sampaiana, Linaria spartea subsp. virgatula and Ulmus procera (for Cr, and Ni) and Bromus hordeaceus and Plantago radicata subsp. radicata (for Ni) indicate that internal detoxification metal tolerance mechanisms might also exist; therefore, their utility for phytoremediation is possible. Furthermore, the plants could grow and propagate in substrata with low nutrient conditions which would be a great advantage in the revegetation of mine tailings. It was also observed that despite lower accumulation, trees of the studied regions can be very effective due to their higher biomass.
Some of the studied species also showed variable accumulation patterns for metals at different soil concentrations. This difference was also noted between parts of the same plant suggesting that full consideration of plant–soil interactions should be taken into account when choosing plant species for developing and utilizing methods such as phytoremediation.
This study was partially supported by the European Fund for Economic and Regional Development (FEDER) through the Program Operational Factors of Competitiveness (COMPETE) and National Funds through the Portuguese Foundation for Science and Technology (PEST-C/MAR/UI 0284/2011, FCOMP 01 0124 FEDER 022689).
Among the Schwann cells (SCs), non-myelinating Schwann cells (NMSCs) represent an important category that was not extensively studied, although the gathered data demonstrate they are essential for axon maintenance and neuronal survival in the peripheral nervous system (PNS). Extending the knowledge on NMSCs biology could open new perspectives on the normal functioning of PNS as well as for better understanding the mechanisms underlying various pathological conditions and further on for developing new therapeutic approaches in peripheral nerve diseases.
\nThe NMSCs encompass two major cell types, according to their distribution: Schwann cells of Remak fibers and the specialized perisynaptic/terminal Schwann cells at neuromuscular junctions (NMJ). In addition in this category are also included the glial cells found in some sensory transducers, such as the Pacinian and Meissner’s corpuscles, as well as in the sensory and autonomic ganglia, where they are called satellite cells [1]. In pathological circumstances like axonal loss or demyelination, the former myelinating Schwann cells also become a class of NMSCs. Conversely, all NMSCs retain the potential to myelinate [2], if they receive the appropriate cues, most of which derive from the associated axons, along with some fate-controlling genes that act cell-autonomously within SCs [3, 4].
\nAll Schwann cells derive from multipotent progenitor cells of the neural crest (\nFigure 2\n). The fate decision mechanism of SCs to become myelinating cells or to form RSCs is not fully understood, although the plasticity of SCs in various studies is recognized. Thus, some studies proved that if myelinated nerve segments are grafted, on a nerve that contains especially unmyelinated fibers, transplanted SCs do not myelinate, and equally, RSCs can produce a myelin sheath when they are grafted onto a myelinated nerve [2, 5].
\nAfter contacting nascent nerves during embryogenesis, neural crest cells give rise to SC precursors (SCP), which further differentiate into immature Schwann cells (iSC), in late embryonic and perinatal nerves (\nFigure 1\n). After birth, iSC will further differentiate either toward myelinating cells or non-myelinating cells according to axon-derived signals. The myelinating SCs form the myelin sheath of large axons (\nFigure 2A\n). The non-myelinating cells ensheath small axons forming unmyelinated fibers, called Remak bundles (\nFigure 2B\n), or they migrate toward the neuromuscular junctions, covering the axon terminals, where they become terminal/perisynaptic/teloglia SCs (\nFigure 2C\n and \nD\n).
\nSchwann cell lineage. SCs derive from the neural crest cells, after contacting nascent nerves during embryogenesis. Neural crest cells give rise to SC precursors, in early embryonic nerves which further differentiate into immature Schwann cells, in late embryonic and perinatal nerves. Postnatally, iSch will further differentiate either toward myelinating cells or non-myelinating cells according to axon-derived signals. The myelinating cells form the myelin sheath of large axons. The non-myelinating cells ensheath small axons forming unmyelinated fibers, called Remak bundles, or they migrate toward the neuromuscular junctions, covering the axon terminals, where they become terminal/perisynaptic/teloglia Schwann cells.
Transmission electron microscopy of myelinated (mn, in A) and nonmyelinated (nn, in B) axons of peripheral nerves embedded in the cytoplasm of Schwann cell (Sch). C and D show the Schwann cells and nerve terminals (nt) in neuromuscular junction. (C) The motor end plate formed by folded sarcolemma (junctional folds, arrows) accommodates knob-like terminal buttons of the motor nerve (nt). (D) The myelin sheath (m) covering the axon ends (nt) in the vicinity of neuromuscular junction and Schwann cell extends into the synaptic cleft (arrowheads).
This chapter addresses the main types of NMSCs, in terms of biological aspects and their role, aiming to highlight their importance for a better understanding of pathological mechanisms underlying various peripheral nervous system diseases.
\nRobert Remak first described the unmyelinated nerve fibers using the nerve fiber teasing technique in 1838 [6], so, in his honor, they were named “Remak fibers.”
\nIn the PNS most nerve fibers are unmyelinated [1], formed by RSCs accommodating a variable number of small-caliber axons (less than 1 μm diameter) (\nFigure 2B\n).
\nRSCs do not produce myelin, but they are essential for normal PNS development and functioning.
\nDuring PNS formation, pockets with multiple axons within a single mesaxon can be encountered. This aspect occurs only occasionally in normal adult Remak fibers where the small diameter axons of C nerve fibers (sensory/afferent), postganglionic sympathetic fibers, and some preganglionic sympathetic or parasympathetic fibers are accommodated in separate grooves of longitudinally interconnected RSCs forming the Remak bundles. Each RSC surrounds many axons, during radial sorting, forming a mesaxon for each axon. It is uncommon for an axon to be in direct contact with the basement membrane of the Schwann cell [4].
\nThe number of axons surrounded by a RSC varies depending on the type of nerve fibers or a particular region along them. Thus, there is a higher number of axons exiting the dorsal root ganglion than in the distal segments of the peripheral nerve. In the cutaneous nerves, the number of axons per RSC decreases as they approach the skin [7], suggesting the existence of specific mechanisms regulating RSC-axons association as they approach their target. Moreover, the distribution of the axons within the Remak bundles varies along the peripheral nerve, with multiple axons within one pocket of the RSC toward the dorsal root and completely isolated axons in the distal segments [8].
\nThere are studies reporting the presence of few short, myelinated internodes along a unmyelinated fiber especially in older animals [9].
\nThus, it appears that the “ensheathment fate” of axons to either become myelinated or unmyelinated fibers relies on local/environmental cues. One of the most extensively studied is the neuregulin 1 type III signaling through ErbB receptors, an axolemmal myelin-inducing factor [3] that promotes the formation of a mesaxon for each unmyelinated axon as well as SC differentiation into myelinating cells, depending on the expression level [10].
\nAnother feature of unmyelinated nerve fibers is that axons may switch between neighboring Remak bundles along the nerve.
\nMoreover, a RSC can surround axons with different functions, for example, both sensitive and sympathetic axons, both axons expressing TrkA (tropomyosin receptor kinase A) receptors with a high affinity for nerve growth factor (NGF) and axons expressing RET (rearranged during transfection) receptors that respond to glial cell line-derived neurotrophic factor (GDNF) and artemin or axons derived from different dorsal ganglia [1].
\nThe RSCs differentiation is governed, at least in part, by neuronal cues, especially by the signaling pathway neuregulin 1 type III (Nrg1-III)/ErbB2/ErbB3 receptor cascades. However, a number of cell-autonomous genes also contribute to SCs differentiation toward RSCs, one of which is gamma-aminobutyric acid type B1 receptor (GABBR1) [4].
\nSCs derive from the neural crest cells, after contacting nascent nerves during embryogenesis. Neural crest cells give rise to SCP, in early embryonic nerves, which further differentiate into iSCs, in late embryonic and perinatal nerves. Postnatally, iSCs will further differentiate either toward myelinating cells or non-myelinating cells according to axon-derived signals. The myelinating cells form the myelin sheath of large axons (larger than 1 μm diameter). The non-myelinating cells ensheath small axons forming unmyelinated fibers, called Remak bundles, or they migrate toward the neuromuscular junctions, where they become terminal/perisynaptic/teloglia Schwann cells (\nFigure 3\n).
\nSchwann cell development and maturation: their role in the evolution of myelinated and unmyelinated peripheral nerve fibers. Schwann cell precursors differentiate into immature Schwann cells which start the process of “radial sorting”. A pro-myelinating Schwann cell envelops a large axon and becomes a myelinating Schwann cell. An immature Schwann cell which ensheaths many small axons becomes mature non-myelinating Schwann cell, forming a Remak bundle.
There are four distinct genes for neuregulins, but neuregulin 1 NRG1 is the best studied. NRG1, also known as glial growth factor (GGF), is a growth factor with EGF domain homology known to induce growth, differentiation, and migration of Schwann cells throughout development [10, 11]. NRG1 has three isoforms out of which type III is considered to be the most important signaling molecule for SC-axon interactions. NRG1 type III is produced by neurons and is released from axons by proteases, such as BACE1, or may remain anchored to the axonal membrane. NR1-III interacts with high-affinity tyrosine kinase receptors ErbB2/ErbB3 heterodimers, triggering the activation of downstream pathways, such as Ras/MAPK and PI3K/Akt SCs. Stimulation of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) cascade was proven to lead to the suppression of myelinating state [12] through ErbB2 and ErbB3 receptors that are expressed in Schwann cells [13]. The NRG1-ErbB signaling pathway seems to play a crucial role in the SCs lineage for both myelinating and non-myelinating SCs and promotes SCP precursor survival after birth as well as during in vitro culturing [10, 14].
\nHowever, recent studies showed that in transgenic animal models where NRG1 is conditionally ablated during postnatal life, there is no reduction in the number of sensory axons but larger, unordered Remak bundles with polyaxonal pockets, where axons are not separated by SC processes, are formed, and some large-diameter axons lose the myelin sheath. Only the sensory function was affected, without changing the survival and axonal maintenance of the neurons [15]. However, after nerve injury, RSCs re-establish normal Remak bundles, suggesting that during adulthood, after the basal lamina was established, axonal sorting is no more required [16].
\nAnother experimental in vivo study on mouse sciatic nerve showed that NRG1 type III Erb2/Erb3 signaling regulates the morphological changes of the SCs. The study used a NRG1 type III knockout mouse model (+/−) with a low expression of NRG1 type III, which produced Remak bundles with a higher number of axons and smaller spaces between axons [17].
\nA number of studies have shown that there are certain genes that control SCs fate [4, 12, 18, 19] and that they act cell-autonomously in SCs. There are genes that can trigger upregulation of NRG1 during differentiation after injury, thus stimulating remyelination and redifferentiation of SCs [20].
\nAn important genetically determining factor during SCs development is the gene for gamma-aminobutyric acid type B1 receptor (GABBR1), which is active mainly in RSCs as compared to myelinating SCs [21]. An in vivo experimental research showed that the absence of GABBR1 in embryonic SCs leads to an increased number of small-caliber axons and Remak bundles and a decreased number of the large-caliber axons [19]. Furthermore, NRG1-III expression was decreased in GABBR1 mutant animals, in correlation with lower mean diameter axons along with a compensatory gene overexpression and protein levels of ErbB2 and ErbB3. Further studies are needed to analyze the requirement and the mechanism of these cell-autonomous genes in SC fate decision.
\nDuring maturation, RSCs extend cell processes that individually encircle each axon with the plasmatic membrane and cytoplasm, separating it from surrounding axons. Naked axons, which were not completely surrounded by RSC cytoplasm and which come into direct contact with other axons, demonstrate failed RSC maturation after nerve injury [22]. Recent studies have shown that the expression level of a protein that is highly expressed in non-myelinating SCs, neuropathy target esterase (Nte), is correlated with SC developmental maturation and remyelination after neuronal injury. However, this protein is not involved in myelination [23].
\nOther proteins, such as mTOR [24, 25, 26], or G-G protein-coupled receptor Gpr126/Adgrg6, through laminin-211 and collagen type IV interactions, are required for both myelinating and non-myelinating SCs growth and function, during developmental stages as well as after nerve injury. Gpr126 controls radial sorting, myelination, SC-axon interactions, as well as Remak bundle formation [27, 28, 29, 30].
\nIn SCs, both deletion and overexpression of mTOR complex I adapter (Raptor) disrupts Remak bundle formation by increasing the number of axons in Remak bundles, with many naked axons [26], or decreasing the number of axons in Remak bundles and aberrant wrapping of multiple membrane-layered axons by RSCs, respectively [24, 31].
\nThe absence of myelin gives Remak fibers a certain plasticity, sprouting, and growth abilities that exceed that of myelinated fibers. That is why they are found especially in PNS, where the risk of physical injuries is much higher than in the CNS.
\nAlthough Remak fibers are found mainly in the PNS, they are also found in the CNS, associated with unmyelinated fibers in the parallel fiber system of the cerebellum and nigrostriatal pathway [1, 32].
\nNMSCs, like other SCs, can also function as immunocompetent cells playing an essential contribution in mounting and modulating of immune response in certain conditions, by antigen presentation and cytokine secretion, as well as by their direct interaction with immune cells. Moreover, NMSCs express specific pattern recognition receptors (PRR) for the detection of pathogens, such as Toll-like receptors (TLRs) and the nucleotide-binding and oligomerization domain (NOD)-like receptor (NLR) family [33, 34, 35].
\nThe crosstalk between immune- and peripheral nerve SCs through a large array of molecules either expressed or recognized by SCs build up the base for nervous-immune system interactions. The subject was extensively reviewed by Tzekova et al. [34]. Moreover, Hu et al. showed that NMSCs located in the thymus develop correlations with thymocytes, lymphocytes, and dendritic cells under normal and pathological conditions. They concluded that NMSCs are highly suitable for studying the local interactions of the PNS and primary lymphoid tissues or organs [36]. The same observations were made by Ma et al. studying the mouse spleen and the interactions between NMSCs and leukocytes [37].
\nAnother role for NMSCs was concluded by the study of Yamazaki et al. which showed that NMSCs maintain hematopoietic stem cell hibernation in the bone marrow niche. They demonstrated that NMSCs proved responsible for activation of TGF-beta latent form. These glial cells, ensheathing autonomic nerves, get in contact with hematopoietic stem cells and maintain them in hibernation by regulating activation of latent TGF-beta [38].
\nTransection of a nerve fiber initiates Wallerian degeneration of the distal stump. As opposed to oligodendrocytes, SCs maintain the ability to dedifferentiate to an immature phenotype in response to nerve injury or disease, and they can actively promote the repair and functional recovery. The repair SCs express inflammatory mediators, such as interleukins and TNFα, as well as anti-inflammatory cytokines (IL-10, Epo, or TGFβ) and growth factors shown to promote Wallerian degeneration, macrophage attraction, and axonal regeneration upon nerve injury [34].
\nA number of molecules have been shown to play important roles in modulating SC behavior after nerve injury.
\nLDL receptor-related protein 1 (LRP1) is a significant factor involved in the development and maintenance of Schwann Cells, both myelinating and NMSCs [39]. LRP1 is one of the molecules upregulated after various types of peripheral nerve injury.
\nThe study of Campana et al. proved that LPR1 upregulation was directly correlated with local production of TNFα and TNFα/LPR1 signaling is one of the survival mechanisms for SC migration and survival observed in in vitro studies [40].
\nAnother signaling receptor that plays an important role in regulation of Schwann cell-axon interactions is fibroblast growth factor receptor (FGFR). Fibroblast growth factor 2 (FGF2) is one of the essential regulators of peripheral nerve regeneration after injury [41]. Three of its receptors, expressed by Schwann cells and dorsal root ganglia neurons, are FGFR1, FGFR2, and FGFR3 which are all upregulated after nerve injury [42].
\nOne day after nerve transection, all SCs start to proliferate within the basal lamina. One week post-injury, RSCs double in length, and after 4 weeks they are three-fold longer and were called repair-supportive Schwann cells. About 50% of repair cells derive from RSCs. The loss of axonal contact determines cells to branch. They form branches lying parallel to the main cell axis, building cellular columns and Bungner bands distal to injury site and offering the support of regenerating sprouts. They will further differentiate to myelinating cells after regeneration [43].
\nMost unmyelinated C-fibers ensheathed by Remak cells are nociceptors [39]. They transmit pain information to the brain. Thus, the dysfunction of RSC induces an altered transmission of the nociceptive stimuli, which leads to severe neuropathic pain.
\nThe specific loss of GABBR1 in SCs results in an increased number of C-unmyelinated fibers, leading to a hypersensitivity to thermal and mechanical stimuli. There is also an alteration of the locomotor coordination, without any injury. It is not known whether these consequences are caused only by the modification of the unmyelinated axon number [19].
\nOther in vivo studies showed that after injury, in LRP1 knockout animals, the resulting hypomyelination and impaired RSCs ensheathment lead to motor dysfunction and mechanical allodynia [39] without any traumatic injury. These pathological changes can cause notable painful symptoms such as mechanical allodynia [39]. In a model with partial nerve injury, the LRP-negative mice have a higher degree of RSC apoptosis, an accelerated degeneration, and further more severe pain in the LRP than the nonmutant mice [39]. These findings suggest the involvement of RSC in the pathophysiology of neuropathic pain and the importance of LRP1 in the physiology of RSC and open the possibility of using RSC as a new therapeutic target in the treatment of neuropathic pain.
\nIn an experimental study in vivo on FGFR1 and FGFR2 single and FGFR1/FGFR2 double conditional knockout mice, Furusho et al. showed that lack of FGFR1 and FGFR2 signaling in NMSCs resulted in sensory axonal neuropathy in unmyelinated C-fibers and the impairment of thermal pain sensitivity [42]. Another study by Chen et al. performed on transgenic mice that postnatally express a dominant-negative ErbB receptor in NMSCs but not in the myelinating ones led to a progressive peripheral neuropathy with loss of unmyelinated axons and heat/cold pain [44]. Altogether, such data suggest the important role of RSCs in in the modulation of pain sensitivity in peripheral sensory neuropathies.
\nCharcot-Marie-Tooth type 1A (CMTA1A) is a genetic disease of the peripheral nervous system in which demyelination and further aberrant remyelination occur in a repeated cycle, with an “onion bulb” appearance in microscopy. From the clinical point of view, CMT1A is characterized by weakness and muscle atrophy in the lower limbs and later on by sensory loss. Myelinating Schwann cells are classically known to be impaired in CMT1A, but it seems that there is also an impairment of the RSC [45]. A proliferation of RSC takes place as a response to the degeneration of the myelinated axons that appear to secrete mitogenic factors [45]. Unexpectedly, no degeneration occurs in the unmyelinated fibers [45]. These findings reveal that RSC are altered in CMT1A, but without any impact on the unmyelinated fibers, in comparison to the relation between myelinating SCs alteration and degenerated myelinated axons. Further studies need to elucidate the contribution of RSC to the pathogenesis of CMT1A.
\nPSC, also known as teloglia or terminal Schwann cell, is a type of non-myelinating Schwann cell which is found above the presynaptic nerve terminal at the level of the NMJ. Louis-Antoine Ranvier described in 1878 the presence of a type of cell in the NMJ distinct from the axon terminal or the muscle fiber. He named this cells “arborization nuclei” because of their widespread projections along the NMJs. Later on, with improved histology techniques and in the era of electron microscopy, several studies identified the presence of this specific type of cell in the NMJ (\nFigure 2C\n).
\nPSCs express several markers that are used to highlight them in situ. The most common approach used is anti-S100b immunolabeling [46]. S100b is a nonspecific marker for all types of SCs, either myelinating or non-myelinating ones. In amphibians only, to distinguish PSCs from myelinating SCs, two specific antibodies are used, peanut agglutinin (PNA) [47] and 2A12 monoclonal antibody [48], which mark the extracellular matrix and the cells’ surface, respectively. Interestingly, PSCs express several myelin proteins such as myelin-associated glycoprotein (MAG), galactocerebroside, protein zero (P0), and 2′,3′-cyclic nucleotide 3′-phosphodiesterase [49]. The cells are not involved in the process of myelination, though the presence of these proteins proves the common origin of the two types of Scs. Additionally, PSCs express on their surface several receptors such as acetylcholine receptors, ATP, purinergic receptors, and L-type voltage-dependent calcium channels that usually take part in the synaptic transmission [50, 51, 52, 53] supporting the hypothesis that PSCs play an active role in the NMJ rather than having only a structural role.
\nSeveral studies determined that the number of PSCs gradually increase after birth [54]. Adult NMJ may contain one up to five PSCs [55, 56, 57], and their number is modulated by PSC-muscle cross talk through neurotrophins [58].
\nPSCs tend to be positioned at the presynaptic side, on top of the motor axon terminal, without the intervention of a basal lamina [55, 56]. Recently a new population of fibroblast-like cells named kranocytes—NMJ-capping cells—was detected on the other side, above the basal lamina of the PSC, covering all other cells of the NMJ. They are thought to have important roles in the NMJ repair after nerve injury [59, 60]. Kranocytes appear to communicate with PSCs via neuregulin signaling pathway to act synergistically after nerve damage [59].
\nMost studies about PSCs were performed either on amphibian (frog) or rodent (mouse) samples [53]. A peculiarity of the frog’s NMJ, where the unmyelinated nerve terminal is completely surrounded by PSCs and does not form dilated terminal buttons and the synaptic contact is formed all along, is that PSCs send finger-like projections into the synaptic cleft, on the presynaptic side, which separate, at a regular distance, active areas where the neurotransmitters are released from covered areas [52, 61]. These active areas correspond on the opposite side to the folds of the sarcolemma, the postsynaptic element of the NMJ, which are rich in nicotinic acetylcholine receptors [52, 61]. In mammals, PSC projections do not reach the synaptic cleft (\nFigure 2D\n).
\nPSCs are involved in the growth and maintenance of the NMJ during development.
\nAlthough these cells do not take part in the initial formation of the axon-muscle junction, PSCs have key contributions in the next stages of NMJ development. In animal models lacking SCs, the axon reaches the muscle in the initial step of the NMJ formation, but only for a brief time [62, 63]. In the absence of SCs, the NMJ gets disrupted, suggesting the vital role of PSCs in the NMJ maintenance during development [64]. Soon after the contact between the axon and the muscle, PSCs intensively divide, sprout, and are primarily involved in the growth of the synapse [64].
\nPSCs are also involved in the physiological processes of polyneuronal innervation and synapse elimination. PSCs are involved in the multiple innervation process of the muscles and suffer a regression in parallel with the axonal withdrawal [1, 65, 66]. After the process of axonal withdrawal, PSCs are engaged in the removal of nerve debris, through phagocytosis [67].
\nThe signaling pathway which facilitates the survival and growth of PSCs and the tight communication between PSCs and motor axons is the neuregulin1-ErbB pathway [1].
\nPSCs have important roles in the maintenance of the NMJ during the adult life as the structural support. Ablation in PSCs on the adult NMJ does not impede the immediate structure and function of the synapse, but after a period of time, the motor axon terminals retract, and the NMJ collapses [64, 68]. Thus PSCs have a significant contribution to the structural maintenance of the synapse under the action of physical factors such as the intense tractions between the nerve and the muscle [53].
\nThese cells dynamically participate in the process of synaptic transmission of information between the motor axons and the muscles, having an important role in the modulation of NMJ activity [53, 57, 69]. Not only PSCs can alter the synaptic transmission, but PSC activity can also be modified by synaptic transmission. Or, as some authors like to say, PSCs can both “talk” and “listen” in the synapse [53, 69].
\nWhen the nerve terminal increases its firing rate and a large amount of neurotransmitter is released in the synaptic cleft, a simultaneous increase of intracellular calcium occurs in PSCs [70, 71]. A similar effect is obtained by applying exogenous acetylcholine and ATP, molecules normally released by the synaptic vesicles, to PSCs [51]. Moreover, the levels of intracellular calcium vary depending on the type of the nerve firing rate, either burst or continuous [72]. These events do not occur in the myelinating SCs and emphasize the detection of synaptic activity by PSCs and the modification of their cellular behavior secondary to the synaptic transmission [69]. This is similar to a decoding process of the synaptic activity. Thereby, the events correspond to the “listening” ability of PSCs in the synapse.
\nThe increase of the PSC intracellular calcium levels does not play only a “decoder” role. This transient raising modulates the synapse by intensifying the neuromuscular transmission. PSCs are expressed on the surface of several G protein-coupled receptors with contributions in the modulation of the synapse activity [73]. Evidences suggest that different ligands of these G protein-coupled receptors determine different changes in the neuromuscular transmission, as follows: a GTP analogue decreased the neurotransmitter release, while a GDP analogue reduced the synaptic depression [73]. These events correspond to the “talking” ability of PSCs in the synapse.
\nTherefore, PSCs are not only a structural, passive component of the NMJ, but an active one. These evidences confirm that the NMJ is a tripartite synapse.
\nPSCs induce and guide the growth of nerve sprouts to re-establish the NMJ after nerve injury.
\nAll the actions that PSCs perform in an attempt to regain the activity of the NMJ appear to be mediated by neuregulin1-ErbB signaling pathway [74].
\nFirst of all, after nerve degeneration, PSCs develop phagocytic traits for the clearance of the debris from the nerve terminals [75].
\nSecond of all, PSCs are involved in the guiding of reinnervation. A few days after the nerve injury, PSCs from the altered NMJ begin to abundantly sprout, and these new processes reach adjacent undamaged synapses [76]. In this manner, “bridges” are established between the innervated and the dennervated NMJs. The role of the newly formed bridges is to facilitate the nerve pathway to find the altered NMJ and to regenerate the synapse more rapidly [69, 76]. However, satellite NMSCs seem to play a role in nerve regeneration after insult as well and might be involved in pathogenic pathways of neuropathic pain [77].
\nMiller Fisher syndrome is a Guillain-Barré syndrome variant with antibodies against GQ1b ganglioside that is clinically characterized by ataxia, ophthalmoplegia, and areflexia. Studies on mouse models revealed that PSCs represent an important target of the autoimmune process, the cellular destruction is complement dependent, and this pathogenic mechanism might be relevant for the human disease [68, 78].
\nAmyotrophic lateral sclerosis (ALS) is a challenge for both the clinician and the researcher due to the obscure pathological mechanisms that are still not completely understood. The role of glial cells in the pathophysiology of the disease is not clear yet. Most probably the SC modifications are a consequence of the neurodegeneration process. However in human patients with ALS, PSCs have abnormal features with cellular processes that extend into the synaptic cleft [79]. Additionally, in ALS mouse models, PSCs have abnormal intracellular levels of calcium, causing a flaw in the synaptic “decoding” function [80].
\nAnother neuromuscular disease in which PSCs appear to be involved is spinal muscular atrophy (SMA). In an ultrastructural study on SMA mouse models, PSCs in the diaphragmatic muscle show changes in their morphology such as vacuole-like translucent profiles and an electron-dense cytoplasm [81]. Another study on SMA mouse models revealed that in the evolution of the disease, there is a progressive loss of PSCs, leading to an improperly remodeling and regeneration of the NMJ [82].
\nAlthough little is known on the NMSC, they are very important players for normal PNS function. Recent studies showed that RSCs play a very important role in the development of peripheral nerves and regeneration after injury. RSCs are also involved in the modulation of pain sensitivity in peripheral sensory neuropathies. Even in the absence of injury, disturbance in axonal-RSC interaction is followed by neuropathic pain.
\nAdditionally, PSCs are mandatorily involved not only in synaptogenesis but also in the growth and maintenance of the normal synapse as well as after denervation. Morphological changes of PSCs were detected in various pathological conditions suggesting their potential involvement in the pathogenic mechanism of such diseases.
\nA better understanding of the molecular mechanisms that govern the development and functioning of NMSCs could broaden the perspective on the pathogenesis and potential therapeutic targets for neuropathy and peripheral nerve injuries.
\nThis work was funded by Ministry of Education and Research in Romania under grants no. 7PFE/16.10.2018 and PN 1N/2019_19.29.01.02.
\nThe authors declare no conflict of interest.
SCs | Schwann cells |
RSC | Remak Schwann cells |
NMSCs | nonmyelinated Schwann cells |
NGF | nerve growth factor |
GGF | glial growth factor |
ERK | extracellular signal-regulated kinase |
Nte | neuropathy target esterase |
FGFR | fibroblast growth factor receptor |
NRG1 | neuregulin 1 |
Nrg1-III | neuregulin 1 type III |
GDNF | glial cell line-derived neurotrophic factor |
GABBR1 | gamma-aminobutyric acid type B1 receptor |
SCP | SC precursors |
iSch | immature Schwann cells |
PSCs | perisynaptic Schwann cells |
NMJ | neuromuscular junction |
PNA | peanut agglutinin |
ALS | amyotrophic lateral sclerosis |
CMT1A | Charcot-Marie-Tooth type 1A |
"Open access contributes to scientific excellence and integrity. It opens up research results to wider analysis. It allows research results to be reused for new discoveries. And it enables the multi-disciplinary research that is needed to solve global 21st century problems. Open access connects science with society. It allows the public to engage with research. To go behind the headlines. And look at the scientific evidence. And it enables policy makers to draw on innovative solutions to societal challenges".
\n\nCarlos Moedas, the European Commissioner for Research Science and Innovation at the STM Annual Frankfurt Conference, October 2016.
",metaTitle:"About Open Access",metaDescription:"Open access contributes to scientific excellence and integrity. It opens up research results to wider analysis. It allows research results to be reused for new discoveries. And it enables the multi-disciplinary research that is needed to solve global 21st century problems. Open access connects science with society. It allows the public to engage with research. To go behind the headlines. And look at the scientific evidence. And it enables policy makers to draw on innovative solutions to societal challenges.\n\nCarlos Moedas, the European Commissioner for Research Science and Innovation at the STM Annual Frankfurt Conference, October 2016.",metaKeywords:null,canonicalURL:"about-open-access",contentRaw:'[{"type":"htmlEditorComponent","content":"The Open Access publishing movement started in the early 2000s when academic leaders from around the world participated in the formation of the Budapest Initiative. They developed recommendations for an Open Access publishing process, “which has worked for the past decade to provide the public with unrestricted, free access to scholarly research—much of which is publicly funded. Making the research publicly available to everyone—free of charge and without most copyright and licensing restrictions—will accelerate scientific research efforts and allow authors to reach a larger number of readers” (reference: http://www.budapestopenaccessinitiative.org)
\\n\\nIntechOpen’s co-founders, both scientists themselves, created the company while undertaking research in robotics at Vienna University. Their goal was to spread research freely “for scientists, by scientists’ to the rest of the world via the Open Access publishing model. The company soon became a signatory of the Budapest Initiative, which currently has more than 1000 supporting organizations worldwide, ranging from universities to funders.
\\n\\nAt IntechOpen today, we are still as committed to working with organizations and people who care about scientific discovery, to putting the academic needs of the scientific community first, and to providing an Open Access environment where scientists can maximize their contribution to scientific advancement. By opening up access to the world’s scientific research articles and book chapters, we aim to facilitate greater opportunity for collaboration, scientific discovery and progress. We subscribe wholeheartedly to the Open Access definition:
\\n\\n“By “open access” to [peer-reviewed research literature], we mean its free availability on the public internet, permitting any users to read, download, copy, distribute, print, search, or link to the full texts of these articles, crawl them for indexing, pass them as data to software, or use them for any other lawful purpose, without financial, legal, or technical barriers other than those inseparable from gaining access to the internet itself. The only constraint on reproduction and distribution, and the only role for copyright in this domain, should be to give authors control over the integrity of their work and the right to be properly acknowledged and cited” (reference: http://www.budapestopenaccessinitiative.org)
\\n\\nOAI-PMH
\\n\\nAs a firm believer in the wider dissemination of knowledge, IntechOpen supports the Open Access Initiative Protocol for Metadata Harvesting (OAI-PMH Version 2.0). Read more
\\n\\nLicense
\\n\\nBook chapters published in edited volumes are distributed under the Creative Commons Attribution 3.0 Unported License (CC BY 3.0). IntechOpen upholds a very flexible Copyright Policy. There is no copyright transfer to the publisher and Authors retain exclusive copyright to their work. All Monographs/Compacts are distributed under the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0). Read more
\\n\\nPeer Review Policies
\\n\\nAll scientific works are Peer Reviewed prior to publishing. Read more
\\n\\nOA Publishing Fees
\\n\\nThe Open Access publishing model employed by IntechOpen eliminates subscription charges and pay-per-view fees, enabling readers to access research at no cost. In order to sustain operations and keep our publications freely accessible we levy an Open Access Publishing Fee for manuscripts, which helps us cover the costs of editorial work and the production of books. Read more
\\n\\nDigital Archiving Policy
\\n\\nIntechOpen is committed to ensuring the long-term preservation and the availability of all scholarly research we publish. We employ a variety of means to enable us to deliver on our commitments to the scientific community. Apart from preservation by the Croatian National Library (for publications prior to April 18, 2018) and the British Library (for publications after April 18, 2018), our entire catalogue is preserved in the CLOCKSS archive.
\\n"}]'},components:[{type:"htmlEditorComponent",content:'The Open Access publishing movement started in the early 2000s when academic leaders from around the world participated in the formation of the Budapest Initiative. They developed recommendations for an Open Access publishing process, “which has worked for the past decade to provide the public with unrestricted, free access to scholarly research—much of which is publicly funded. Making the research publicly available to everyone—free of charge and without most copyright and licensing restrictions—will accelerate scientific research efforts and allow authors to reach a larger number of readers” (reference: http://www.budapestopenaccessinitiative.org)
\n\nIntechOpen’s co-founders, both scientists themselves, created the company while undertaking research in robotics at Vienna University. Their goal was to spread research freely “for scientists, by scientists’ to the rest of the world via the Open Access publishing model. The company soon became a signatory of the Budapest Initiative, which currently has more than 1000 supporting organizations worldwide, ranging from universities to funders.
\n\nAt IntechOpen today, we are still as committed to working with organizations and people who care about scientific discovery, to putting the academic needs of the scientific community first, and to providing an Open Access environment where scientists can maximize their contribution to scientific advancement. By opening up access to the world’s scientific research articles and book chapters, we aim to facilitate greater opportunity for collaboration, scientific discovery and progress. We subscribe wholeheartedly to the Open Access definition:
\n\n“By “open access” to [peer-reviewed research literature], we mean its free availability on the public internet, permitting any users to read, download, copy, distribute, print, search, or link to the full texts of these articles, crawl them for indexing, pass them as data to software, or use them for any other lawful purpose, without financial, legal, or technical barriers other than those inseparable from gaining access to the internet itself. The only constraint on reproduction and distribution, and the only role for copyright in this domain, should be to give authors control over the integrity of their work and the right to be properly acknowledged and cited” (reference: http://www.budapestopenaccessinitiative.org)
\n\nOAI-PMH
\n\nAs a firm believer in the wider dissemination of knowledge, IntechOpen supports the Open Access Initiative Protocol for Metadata Harvesting (OAI-PMH Version 2.0). Read more
\n\nLicense
\n\nBook chapters published in edited volumes are distributed under the Creative Commons Attribution 3.0 Unported License (CC BY 3.0). IntechOpen upholds a very flexible Copyright Policy. There is no copyright transfer to the publisher and Authors retain exclusive copyright to their work. All Monographs/Compacts are distributed under the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0). Read more
\n\nPeer Review Policies
\n\nAll scientific works are Peer Reviewed prior to publishing. Read more
\n\nOA Publishing Fees
\n\nThe Open Access publishing model employed by IntechOpen eliminates subscription charges and pay-per-view fees, enabling readers to access research at no cost. In order to sustain operations and keep our publications freely accessible we levy an Open Access Publishing Fee for manuscripts, which helps us cover the costs of editorial work and the production of books. Read more
\n\nDigital Archiving Policy
\n\nIntechOpen is committed to ensuring the long-term preservation and the availability of all scholarly research we publish. We employ a variety of means to enable us to deliver on our commitments to the scientific community. Apart from preservation by the Croatian National Library (for publications prior to April 18, 2018) and the British Library (for publications after April 18, 2018), our entire catalogue is preserved in the CLOCKSS archive.
\n'}]},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:5763},{group:"region",caption:"Middle and South America",value:2,count:5227},{group:"region",caption:"Africa",value:3,count:1717},{group:"region",caption:"Asia",value:4,count:10365},{group:"region",caption:"Australia and Oceania",value:5,count:897},{group:"region",caption:"Europe",value:6,count:15784}],offset:12,limit:12,total:118187},chapterEmbeded:{data:{}},editorApplication:{success:null,errors:{}},ofsBooks:{filterParams:{sort:"dateEndThirdStepPublish"},books:[{type:"book",id:"10231",title:"Proton Therapy",subtitle:null,isOpenForSubmission:!0,hash:"f4a9009287953c8d1d89f0fa9b7597b0",slug:null,bookSignature:"",coverURL:"https://cdn.intechopen.com/books/images_new/10231.jpg",editedByType:null,editors:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10652",title:"Visual Object Tracking",subtitle:null,isOpenForSubmission:!0,hash:"96f3ee634a7ba49fa195e50475412af4",slug:null,bookSignature:"",coverURL:"https://cdn.intechopen.com/books/images_new/10652.jpg",editedByType:null,editors:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10653",title:"Optimization Algorithms",subtitle:null,isOpenForSubmission:!0,hash:"753812dbb9a6f6b57645431063114f6c",slug:null,bookSignature:"",coverURL:"https://cdn.intechopen.com/books/images_new/10653.jpg",editedByType:null,editors:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10655",title:"Motion Planning",subtitle:null,isOpenForSubmission:!0,hash:"809b5e290cf2dade9e7e0a5ae0ef3df0",slug:null,bookSignature:"",coverURL:"https://cdn.intechopen.com/books/images_new/10655.jpg",editedByType:null,editors:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10657",title:"Service Robots",subtitle:null,isOpenForSubmission:!0,hash:"5f81b9eea6eb3f9af984031b7af35588",slug:null,bookSignature:"",coverURL:"https://cdn.intechopen.com/books/images_new/10657.jpg",editedByType:null,editors:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10662",title:"Pedagogy",subtitle:null,isOpenForSubmission:!0,hash:"c858e1c6fb878d3b895acbacec624576",slug:null,bookSignature:"",coverURL:"https://cdn.intechopen.com/books/images_new/10662.jpg",editedByType:null,editors:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10673",title:"The Psychology of Trust",subtitle:null,isOpenForSubmission:!0,hash:"1f6cac41fd145f718ac0866264499cc8",slug:null,bookSignature:"",coverURL:"https://cdn.intechopen.com/books/images_new/10673.jpg",editedByType:null,editors:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10675",title:"Hydrostatics",subtitle:null,isOpenForSubmission:!0,hash:"c86c2fa9f835d4ad5e7efd8b01921866",slug:null,bookSignature:"",coverURL:"https://cdn.intechopen.com/books/images_new/10675.jpg",editedByType:null,editors:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10677",title:"Topology",subtitle:null,isOpenForSubmission:!0,hash:"85eac84b173d785f989522397616124e",slug:null,bookSignature:"",coverURL:"https://cdn.intechopen.com/books/images_new/10677.jpg",editedByType:null,editors:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10678",title:"Biostatistics",subtitle:null,isOpenForSubmission:!0,hash:"f63db439474a574454a66894db8b394c",slug:null,bookSignature:"",coverURL:"https://cdn.intechopen.com/books/images_new/10678.jpg",editedByType:null,editors:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10679",title:"Mass Production",subtitle:null,isOpenForSubmission:!0,hash:"2dae91102099b1a07be1a36a68852829",slug:null,bookSignature:"",coverURL:"https://cdn.intechopen.com/books/images_new/10679.jpg",editedByType:null,editors:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10684",title:"Biorefineries",subtitle:null,isOpenForSubmission:!0,hash:"23962c6b77348bcbf247c673d34562f6",slug:null,bookSignature:"",coverURL:"https://cdn.intechopen.com/books/images_new/10684.jpg",editedByType:null,editors:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}}],filtersByTopic:[{group:"topic",caption:"Agricultural and Biological Sciences",value:5,count:13},{group:"topic",caption:"Biochemistry, Genetics and Molecular Biology",value:6,count:3},{group:"topic",caption:"Business, Management and Economics",value:7,count:1},{group:"topic",caption:"Chemistry",value:8,count:6},{group:"topic",caption:"Computer and Information Science",value:9,count:6},{group:"topic",caption:"Earth and Planetary Sciences",value:10,count:7},{group:"topic",caption:"Engineering",value:11,count:14},{group:"topic",caption:"Environmental Sciences",value:12,count:2},{group:"topic",caption:"Immunology and Microbiology",value:13,count:3},{group:"topic",caption:"Materials Science",value:14,count:4},{group:"topic",caption:"Mathematics",value:15,count:1},{group:"topic",caption:"Medicine",value:16,count:27},{group:"topic",caption:"Neuroscience",value:18,count:1},{group:"topic",caption:"Pharmacology, Toxicology and Pharmaceutical Science",value:19,count:2},{group:"topic",caption:"Physics",value:20,count:2},{group:"topic",caption:"Psychology",value:21,count:4},{group:"topic",caption:"Social Sciences",value:23,count:2},{group:"topic",caption:"Technology",value:24,count:1},{group:"topic",caption:"Veterinary Medicine and Science",value:25,count:1}],offset:12,limit:12,total:190},popularBooks:{featuredBooks:[{type:"book",id:"9385",title:"Renewable Energy",subtitle:"Technologies and Applications",isOpenForSubmission:!1,hash:"a6b446d19166f17f313008e6c056f3d8",slug:"renewable-energy-technologies-and-applications",bookSignature:"Tolga Taner, Archana Tiwari and Taha Selim Ustun",coverURL:"https://cdn.intechopen.com/books/images_new/9385.jpg",editors:[{id:"197240",title:"Associate Prof.",name:"Tolga",middleName:null,surname:"Taner",slug:"tolga-taner",fullName:"Tolga Taner"}],equalEditorOne:{id:"186791",title:"Dr.",name:"Archana",middleName:null,surname:"Tiwari",slug:"archana-tiwari",fullName:"Archana Tiwari",profilePictureURL:"https://mts.intechopen.com/storage/users/186791/images/system/186791.jpg",biography:"Dr. Archana Tiwari is Associate Professor at Amity University, India. Her research interests include renewable sources of energy from microalgae and further utilizing the residual biomass for the generation of value-added products, bioremediation through microalgae and microbial consortium, antioxidative enzymes and stress, and nutraceuticals from microalgae. She has been working on algal biotechnology for the last two decades. She has published her research in many international journals and has authored many books and chapters with renowned publishing houses. She has also delivered talks as an invited speaker at many national and international conferences. Dr. Tiwari is the recipient of several awards including Researcher of the Year and Distinguished Scientist.",institutionString:"Amity University",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"3",totalChapterViews:"0",totalEditedBooks:"1",institution:{name:"Amity University",institutionURL:null,country:{name:"India"}}},equalEditorTwo:{id:"197609",title:"Prof.",name:"Taha Selim",middleName:null,surname:"Ustun",slug:"taha-selim-ustun",fullName:"Taha Selim Ustun",profilePictureURL:"https://mts.intechopen.com/storage/users/197609/images/system/197609.jpeg",biography:"Dr. Taha Selim Ustun received a Ph.D. in Electrical Engineering from Victoria University, Melbourne, Australia. He is a researcher with the Fukushima Renewable Energy Institute, AIST (FREA), where he leads the Smart Grid Cybersecurity Laboratory. Prior to that, he was a faculty member with the School of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, USA. His current research interests include power systems protection, communication in power networks, distributed generation, microgrids, electric vehicle integration, and cybersecurity in smart grids. He serves on the editorial boards of IEEE Access, IEEE Transactions on Industrial Informatics, Energies, Electronics, Electricity, World Electric Vehicle and Information journals. Dr. Ustun is a member of the IEEE 2004 and 2800, IEC Renewable Energy Management WG 8, and IEC TC 57 WG17. He has been invited to run specialist courses in Africa, India, and China. He has delivered talks for the Qatar Foundation, the World Energy Council, the Waterloo Global Science Initiative, and the European Union Energy Initiative (EUEI). His research has attracted funding from prestigious programs in Japan, Australia, the European Union, and North America.",institutionString:"Fukushima Renewable Energy Institute, AIST (FREA)",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"1",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"National Institute of Advanced Industrial Science and Technology",institutionURL:null,country:{name:"Japan"}}},equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"8985",title:"Natural Resources Management and Biological Sciences",subtitle:null,isOpenForSubmission:!1,hash:"5c2e219a6c021a40b5a20c041dea88c4",slug:"natural-resources-management-and-biological-sciences",bookSignature:"Edward R. Rhodes and Humood Naser",coverURL:"https://cdn.intechopen.com/books/images_new/8985.jpg",editors:[{id:"280886",title:"Prof.",name:"Edward R",middleName:null,surname:"Rhodes",slug:"edward-r-rhodes",fullName:"Edward R Rhodes"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9027",title:"Human Blood Group Systems and Haemoglobinopathies",subtitle:null,isOpenForSubmission:!1,hash:"d00d8e40b11cfb2547d1122866531c7e",slug:"human-blood-group-systems-and-haemoglobinopathies",bookSignature:"Osaro Erhabor and Anjana Munshi",coverURL:"https://cdn.intechopen.com/books/images_new/9027.jpg",editors:[{id:"35140",title:null,name:"Osaro",middleName:null,surname:"Erhabor",slug:"osaro-erhabor",fullName:"Osaro Erhabor"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"7841",title:"New Insights Into Metabolic Syndrome",subtitle:null,isOpenForSubmission:!1,hash:"ef5accfac9772b9e2c9eff884f085510",slug:"new-insights-into-metabolic-syndrome",bookSignature:"Akikazu Takada",coverURL:"https://cdn.intechopen.com/books/images_new/7841.jpg",editors:[{id:"248459",title:"Dr.",name:"Akikazu",middleName:null,surname:"Takada",slug:"akikazu-takada",fullName:"Akikazu Takada"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"8558",title:"Aerodynamics",subtitle:null,isOpenForSubmission:!1,hash:"db7263fc198dfb539073ba0260a7f1aa",slug:"aerodynamics",bookSignature:"Mofid Gorji-Bandpy and Aly-Mousaad Aly",coverURL:"https://cdn.intechopen.com/books/images_new/8558.jpg",editors:[{id:"35542",title:"Prof.",name:"Mofid",middleName:null,surname:"Gorji-Bandpy",slug:"mofid-gorji-bandpy",fullName:"Mofid Gorji-Bandpy"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9668",title:"Chemistry and Biochemistry of Winemaking, Wine Stabilization and Aging",subtitle:null,isOpenForSubmission:!1,hash:"c5484276a314628acf21ec1bdc3a86b9",slug:"chemistry-and-biochemistry-of-winemaking-wine-stabilization-and-aging",bookSignature:"Fernanda Cosme, Fernando M. Nunes and Luís Filipe-Ribeiro",coverURL:"https://cdn.intechopen.com/books/images_new/9668.jpg",editors:[{id:"186819",title:"Prof.",name:"Fernanda",middleName:null,surname:"Cosme",slug:"fernanda-cosme",fullName:"Fernanda Cosme"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"7847",title:"Medical Toxicology",subtitle:null,isOpenForSubmission:!1,hash:"db9b65bea093de17a0855a1b27046247",slug:"medical-toxicology",bookSignature:"Pınar Erkekoglu and Tomohisa Ogawa",coverURL:"https://cdn.intechopen.com/books/images_new/7847.jpg",editors:[{id:"109978",title:"Prof.",name:"Pınar",middleName:null,surname:"Erkekoglu",slug:"pinar-erkekoglu",fullName:"Pınar Erkekoglu"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"8620",title:"Mining Techniques",subtitle:"Past, Present and Future",isOpenForSubmission:!1,hash:"b65658f81d14e9e57e49377869d3a575",slug:"mining-techniques-past-present-and-future",bookSignature:"Abhay Soni",coverURL:"https://cdn.intechopen.com/books/images_new/8620.jpg",editors:[{id:"271093",title:"Dr.",name:"Abhay",middleName:null,surname:"Soni",slug:"abhay-soni",fullName:"Abhay Soni"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9660",title:"Inland Waters",subtitle:"Dynamics and Ecology",isOpenForSubmission:!1,hash:"975c26819ceb11a926793bc2adc62bd6",slug:"inland-waters-dynamics-and-ecology",bookSignature:"Adam Devlin, Jiayi Pan and Mohammad Manjur Shah",coverURL:"https://cdn.intechopen.com/books/images_new/9660.jpg",editors:[{id:"280757",title:"Dr.",name:"Adam",middleName:"Thomas",surname:"Devlin",slug:"adam-devlin",fullName:"Adam Devlin"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9122",title:"Cosmetic Surgery",subtitle:null,isOpenForSubmission:!1,hash:"207026ca4a4125e17038e770d00ee152",slug:"cosmetic-surgery",bookSignature:"Yueh-Bih Tang",coverURL:"https://cdn.intechopen.com/books/images_new/9122.jpg",editors:[{id:"202122",title:"Prof.",name:"Yueh-Bih",middleName:null,surname:"Tang",slug:"yueh-bih-tang",fullName:"Yueh-Bih Tang"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9043",title:"Parenting",subtitle:"Studies by an Ecocultural and Transactional Perspective",isOpenForSubmission:!1,hash:"6d21066c7438e459e4c6fb13217a5c8c",slug:"parenting-studies-by-an-ecocultural-and-transactional-perspective",bookSignature:"Loredana Benedetto and Massimo Ingrassia",coverURL:"https://cdn.intechopen.com/books/images_new/9043.jpg",editors:[{id:"193200",title:"Prof.",name:"Loredana",middleName:null,surname:"Benedetto",slug:"loredana-benedetto",fullName:"Loredana Benedetto"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9731",title:"Oxidoreductase",subtitle:null,isOpenForSubmission:!1,hash:"852e6f862c85fc3adecdbaf822e64e6e",slug:"oxidoreductase",bookSignature:"Mahmoud Ahmed Mansour",coverURL:"https://cdn.intechopen.com/books/images_new/9731.jpg",editors:[{id:"224662",title:"Prof.",name:"Mahmoud Ahmed",middleName:null,surname:"Mansour",slug:"mahmoud-ahmed-mansour",fullName:"Mahmoud Ahmed Mansour"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}}],offset:12,limit:12,total:5221},hotBookTopics:{hotBooks:[],offset:0,limit:12,total:null},publish:{},publishingProposal:{success:null,errors:{}},books:{featuredBooks:[{type:"book",id:"9385",title:"Renewable Energy",subtitle:"Technologies and Applications",isOpenForSubmission:!1,hash:"a6b446d19166f17f313008e6c056f3d8",slug:"renewable-energy-technologies-and-applications",bookSignature:"Tolga Taner, Archana Tiwari and Taha Selim Ustun",coverURL:"https://cdn.intechopen.com/books/images_new/9385.jpg",editors:[{id:"197240",title:"Associate Prof.",name:"Tolga",middleName:null,surname:"Taner",slug:"tolga-taner",fullName:"Tolga Taner"}],equalEditorOne:{id:"186791",title:"Dr.",name:"Archana",middleName:null,surname:"Tiwari",slug:"archana-tiwari",fullName:"Archana Tiwari",profilePictureURL:"https://mts.intechopen.com/storage/users/186791/images/system/186791.jpg",biography:"Dr. Archana Tiwari is Associate Professor at Amity University, India. Her research interests include renewable sources of energy from microalgae and further utilizing the residual biomass for the generation of value-added products, bioremediation through microalgae and microbial consortium, antioxidative enzymes and stress, and nutraceuticals from microalgae. She has been working on algal biotechnology for the last two decades. She has published her research in many international journals and has authored many books and chapters with renowned publishing houses. She has also delivered talks as an invited speaker at many national and international conferences. Dr. Tiwari is the recipient of several awards including Researcher of the Year and Distinguished Scientist.",institutionString:"Amity University",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"3",totalChapterViews:"0",totalEditedBooks:"1",institution:{name:"Amity University",institutionURL:null,country:{name:"India"}}},equalEditorTwo:{id:"197609",title:"Prof.",name:"Taha Selim",middleName:null,surname:"Ustun",slug:"taha-selim-ustun",fullName:"Taha Selim Ustun",profilePictureURL:"https://mts.intechopen.com/storage/users/197609/images/system/197609.jpeg",biography:"Dr. Taha Selim Ustun received a Ph.D. in Electrical Engineering from Victoria University, Melbourne, Australia. He is a researcher with the Fukushima Renewable Energy Institute, AIST (FREA), where he leads the Smart Grid Cybersecurity Laboratory. Prior to that, he was a faculty member with the School of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, USA. His current research interests include power systems protection, communication in power networks, distributed generation, microgrids, electric vehicle integration, and cybersecurity in smart grids. He serves on the editorial boards of IEEE Access, IEEE Transactions on Industrial Informatics, Energies, Electronics, Electricity, World Electric Vehicle and Information journals. Dr. Ustun is a member of the IEEE 2004 and 2800, IEC Renewable Energy Management WG 8, and IEC TC 57 WG17. He has been invited to run specialist courses in Africa, India, and China. He has delivered talks for the Qatar Foundation, the World Energy Council, the Waterloo Global Science Initiative, and the European Union Energy Initiative (EUEI). His research has attracted funding from prestigious programs in Japan, Australia, the European Union, and North America.",institutionString:"Fukushima Renewable Energy Institute, AIST (FREA)",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"1",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"National Institute of Advanced Industrial Science and Technology",institutionURL:null,country:{name:"Japan"}}},equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"8985",title:"Natural Resources Management and Biological Sciences",subtitle:null,isOpenForSubmission:!1,hash:"5c2e219a6c021a40b5a20c041dea88c4",slug:"natural-resources-management-and-biological-sciences",bookSignature:"Edward R. Rhodes and Humood Naser",coverURL:"https://cdn.intechopen.com/books/images_new/8985.jpg",editors:[{id:"280886",title:"Prof.",name:"Edward R",middleName:null,surname:"Rhodes",slug:"edward-r-rhodes",fullName:"Edward R Rhodes"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9027",title:"Human Blood Group Systems and Haemoglobinopathies",subtitle:null,isOpenForSubmission:!1,hash:"d00d8e40b11cfb2547d1122866531c7e",slug:"human-blood-group-systems-and-haemoglobinopathies",bookSignature:"Osaro Erhabor and Anjana Munshi",coverURL:"https://cdn.intechopen.com/books/images_new/9027.jpg",editors:[{id:"35140",title:null,name:"Osaro",middleName:null,surname:"Erhabor",slug:"osaro-erhabor",fullName:"Osaro Erhabor"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"7841",title:"New Insights Into Metabolic Syndrome",subtitle:null,isOpenForSubmission:!1,hash:"ef5accfac9772b9e2c9eff884f085510",slug:"new-insights-into-metabolic-syndrome",bookSignature:"Akikazu Takada",coverURL:"https://cdn.intechopen.com/books/images_new/7841.jpg",editors:[{id:"248459",title:"Dr.",name:"Akikazu",middleName:null,surname:"Takada",slug:"akikazu-takada",fullName:"Akikazu Takada"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"8558",title:"Aerodynamics",subtitle:null,isOpenForSubmission:!1,hash:"db7263fc198dfb539073ba0260a7f1aa",slug:"aerodynamics",bookSignature:"Mofid Gorji-Bandpy and Aly-Mousaad Aly",coverURL:"https://cdn.intechopen.com/books/images_new/8558.jpg",editors:[{id:"35542",title:"Prof.",name:"Mofid",middleName:null,surname:"Gorji-Bandpy",slug:"mofid-gorji-bandpy",fullName:"Mofid Gorji-Bandpy"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9668",title:"Chemistry and Biochemistry of Winemaking, Wine Stabilization and Aging",subtitle:null,isOpenForSubmission:!1,hash:"c5484276a314628acf21ec1bdc3a86b9",slug:"chemistry-and-biochemistry-of-winemaking-wine-stabilization-and-aging",bookSignature:"Fernanda Cosme, Fernando M. Nunes and Luís Filipe-Ribeiro",coverURL:"https://cdn.intechopen.com/books/images_new/9668.jpg",editors:[{id:"186819",title:"Prof.",name:"Fernanda",middleName:null,surname:"Cosme",slug:"fernanda-cosme",fullName:"Fernanda Cosme"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"7847",title:"Medical Toxicology",subtitle:null,isOpenForSubmission:!1,hash:"db9b65bea093de17a0855a1b27046247",slug:"medical-toxicology",bookSignature:"Pınar Erkekoglu and Tomohisa Ogawa",coverURL:"https://cdn.intechopen.com/books/images_new/7847.jpg",editors:[{id:"109978",title:"Prof.",name:"Pınar",middleName:null,surname:"Erkekoglu",slug:"pinar-erkekoglu",fullName:"Pınar Erkekoglu"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"8620",title:"Mining Techniques",subtitle:"Past, Present and Future",isOpenForSubmission:!1,hash:"b65658f81d14e9e57e49377869d3a575",slug:"mining-techniques-past-present-and-future",bookSignature:"Abhay Soni",coverURL:"https://cdn.intechopen.com/books/images_new/8620.jpg",editors:[{id:"271093",title:"Dr.",name:"Abhay",middleName:null,surname:"Soni",slug:"abhay-soni",fullName:"Abhay Soni"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9660",title:"Inland Waters",subtitle:"Dynamics and Ecology",isOpenForSubmission:!1,hash:"975c26819ceb11a926793bc2adc62bd6",slug:"inland-waters-dynamics-and-ecology",bookSignature:"Adam Devlin, Jiayi Pan and Mohammad Manjur Shah",coverURL:"https://cdn.intechopen.com/books/images_new/9660.jpg",editors:[{id:"280757",title:"Dr.",name:"Adam",middleName:"Thomas",surname:"Devlin",slug:"adam-devlin",fullName:"Adam Devlin"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9122",title:"Cosmetic Surgery",subtitle:null,isOpenForSubmission:!1,hash:"207026ca4a4125e17038e770d00ee152",slug:"cosmetic-surgery",bookSignature:"Yueh-Bih Tang",coverURL:"https://cdn.intechopen.com/books/images_new/9122.jpg",editors:[{id:"202122",title:"Prof.",name:"Yueh-Bih",middleName:null,surname:"Tang",slug:"yueh-bih-tang",fullName:"Yueh-Bih Tang"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}}],latestBooks:[{type:"book",id:"9550",title:"Entrepreneurship",subtitle:"Contemporary Issues",isOpenForSubmission:!1,hash:"9b4ac1ee5b743abf6f88495452b1e5e7",slug:"entrepreneurship-contemporary-issues",bookSignature:"Mladen Turuk",coverURL:"https://cdn.intechopen.com/books/images_new/9550.jpg",editedByType:"Edited by",editors:[{id:"319755",title:"Prof.",name:"Mladen",middleName:null,surname:"Turuk",slug:"mladen-turuk",fullName:"Mladen Turuk"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10065",title:"Wavelet Theory",subtitle:null,isOpenForSubmission:!1,hash:"d8868e332169597ba2182d9b004d60de",slug:"wavelet-theory",bookSignature:"Somayeh Mohammady",coverURL:"https://cdn.intechopen.com/books/images_new/10065.jpg",editedByType:"Edited by",editors:[{id:"109280",title:"Dr.",name:"Somayeh",middleName:null,surname:"Mohammady",slug:"somayeh-mohammady",fullName:"Somayeh Mohammady"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9313",title:"Clay Science and Technology",subtitle:null,isOpenForSubmission:!1,hash:"6fa7e70396ff10620e032bb6cfa6fb72",slug:"clay-science-and-technology",bookSignature:"Gustavo Morari Do Nascimento",coverURL:"https://cdn.intechopen.com/books/images_new/9313.jpg",editedByType:"Edited by",editors:[{id:"7153",title:"Prof.",name:"Gustavo",middleName:null,surname:"Morari Do Nascimento",slug:"gustavo-morari-do-nascimento",fullName:"Gustavo Morari Do Nascimento"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9888",title:"Nuclear Power Plants",subtitle:"The Processes from the Cradle to the Grave",isOpenForSubmission:!1,hash:"c2c8773e586f62155ab8221ebb72a849",slug:"nuclear-power-plants-the-processes-from-the-cradle-to-the-grave",bookSignature:"Nasser Awwad",coverURL:"https://cdn.intechopen.com/books/images_new/9888.jpg",editedByType:"Edited by",editors:[{id:"145209",title:"Prof.",name:"Nasser",middleName:"S",surname:"Awwad",slug:"nasser-awwad",fullName:"Nasser Awwad"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"8098",title:"Resources of Water",subtitle:null,isOpenForSubmission:!1,hash:"d251652996624d932ef7b8ed62cf7cfc",slug:"resources-of-water",bookSignature:"Prathna Thanjavur Chandrasekaran, Muhammad Salik Javaid, Aftab Sadiq",coverURL:"https://cdn.intechopen.com/books/images_new/8098.jpg",editedByType:"Edited by",editors:[{id:"167917",title:"Dr.",name:"Prathna",middleName:null,surname:"Thanjavur Chandrasekaran",slug:"prathna-thanjavur-chandrasekaran",fullName:"Prathna Thanjavur Chandrasekaran"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9644",title:"Glaciers and the Polar Environment",subtitle:null,isOpenForSubmission:!1,hash:"e8cfdc161794e3753ced54e6ff30873b",slug:"glaciers-and-the-polar-environment",bookSignature:"Masaki Kanao, Danilo Godone and Niccolò Dematteis",coverURL:"https://cdn.intechopen.com/books/images_new/9644.jpg",editedByType:"Edited by",editors:[{id:"51959",title:"Dr.",name:"Masaki",middleName:null,surname:"Kanao",slug:"masaki-kanao",fullName:"Masaki Kanao"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10432",title:"Casting Processes and Modelling of Metallic Materials",subtitle:null,isOpenForSubmission:!1,hash:"2c5c9df938666bf5d1797727db203a6d",slug:"casting-processes-and-modelling-of-metallic-materials",bookSignature:"Zakaria Abdallah and Nada Aldoumani",coverURL:"https://cdn.intechopen.com/books/images_new/10432.jpg",editedByType:"Edited by",editors:[{id:"201670",title:"Dr.",name:"Zak",middleName:null,surname:"Abdallah",slug:"zak-abdallah",fullName:"Zak Abdallah"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9671",title:"Macrophages",subtitle:null,isOpenForSubmission:!1,hash:"03b00fdc5f24b71d1ecdfd75076bfde6",slug:"macrophages",bookSignature:"Hridayesh Prakash",coverURL:"https://cdn.intechopen.com/books/images_new/9671.jpg",editedByType:"Edited by",editors:[{id:"287184",title:"Dr.",name:"Hridayesh",middleName:null,surname:"Prakash",slug:"hridayesh-prakash",fullName:"Hridayesh Prakash"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"8415",title:"Extremophilic Microbes and Metabolites",subtitle:"Diversity, Bioprospecting and Biotechnological Applications",isOpenForSubmission:!1,hash:"93e0321bc93b89ff73730157738f8f97",slug:"extremophilic-microbes-and-metabolites-diversity-bioprospecting-and-biotechnological-applications",bookSignature:"Afef Najjari, Ameur Cherif, Haïtham Sghaier and Hadda Imene Ouzari",coverURL:"https://cdn.intechopen.com/books/images_new/8415.jpg",editedByType:"Edited by",editors:[{id:"196823",title:"Dr.",name:"Afef",middleName:null,surname:"Najjari",slug:"afef-najjari",fullName:"Afef Najjari"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9731",title:"Oxidoreductase",subtitle:null,isOpenForSubmission:!1,hash:"852e6f862c85fc3adecdbaf822e64e6e",slug:"oxidoreductase",bookSignature:"Mahmoud Ahmed Mansour",coverURL:"https://cdn.intechopen.com/books/images_new/9731.jpg",editedByType:"Edited by",editors:[{id:"224662",title:"Prof.",name:"Mahmoud Ahmed",middleName:null,surname:"Mansour",slug:"mahmoud-ahmed-mansour",fullName:"Mahmoud Ahmed Mansour"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}}]},subject:{topic:{id:"304",title:"Urban Agriculture",slug:"urban-agriculture",parent:{title:"Agricultural Engineering",slug:"agricultural-and-biological-sciences-agricultural-engineering"},numberOfBooks:3,numberOfAuthorsAndEditors:69,numberOfWosCitations:4,numberOfCrossrefCitations:7,numberOfDimensionsCitations:22,videoUrl:null,fallbackUrl:null,description:null},booksByTopicFilter:{topicSlug:"urban-agriculture",sort:"-publishedDate",limit:12,offset:0},booksByTopicCollection:[{type:"book",id:"8939",title:"Urban Horticulture",subtitle:"Necessity of the Future",isOpenForSubmission:!1,hash:"5db1ff90f7e404baf4e42cdfbe0b9755",slug:"urban-horticulture-necessity-of-the-future",bookSignature:"Shashank Shekhar Solankey, Shirin Akhtar, Alejandro Isabel Luna Maldonado, Humberto Rodriguez-Fuentes, Juan Antonio Vidales Contreras and Julia Mariana Márquez Reyes",coverURL:"https://cdn.intechopen.com/books/images_new/8939.jpg",editedByType:"Edited by",editors:[{id:"210702",title:"Dr.",name:"Shashank Shekhar",middleName:null,surname:"Solankey",slug:"shashank-shekhar-solankey",fullName:"Shashank Shekhar Solankey"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"8308",title:"Agricultural Economics",subtitle:"Current Issues",isOpenForSubmission:!1,hash:"138b8e4117a40c74fc41ec72d552fa9f",slug:"agricultural-economics-current-issues",bookSignature:"Surendra N. Kulshreshtha",coverURL:"https://cdn.intechopen.com/books/images_new/8308.jpg",editedByType:"Edited by",editors:[{id:"37057",title:"Dr.",name:"Surendra N.",middleName:null,surname:"Kulshreshtha",slug:"surendra-n.-kulshreshtha",fullName:"Surendra N. Kulshreshtha"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"5227",title:"Urban Agriculture",subtitle:null,isOpenForSubmission:!1,hash:"722ebe60b63f7c01577d063a3e39c36a",slug:"urban-agriculture",bookSignature:"Mohamed Samer",coverURL:"https://cdn.intechopen.com/books/images_new/5227.jpg",editedByType:"Edited by",editors:[{id:"175050",title:"Prof.",name:"Mohamed",middleName:null,surname:"Samer",slug:"mohamed-samer",fullName:"Mohamed Samer"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}}],booksByTopicTotal:3,mostCitedChapters:[{id:"69221",doi:"10.5772/intechopen.89279",title:"Social Value of Urban Rooftop Farming: A Hong Kong Case Study",slug:"social-value-of-urban-rooftop-farming-a-hong-kong-case-study",totalDownloads:463,totalCrossrefCites:2,totalDimensionsCites:4,book:{slug:"agricultural-economics-current-issues",title:"Agricultural Economics",fullTitle:"Agricultural Economics - Current Issues"},signatures:"Ting Wang and Mathew Pryor",authors:[{id:"289674",title:"Ph.D. Student",name:"Ting",middleName:null,surname:"Wang",slug:"ting-wang",fullName:"Ting Wang"},{id:"289677",title:"Prof.",name:"Mathew",middleName:null,surname:"Pryor",slug:"mathew-pryor",fullName:"Mathew Pryor"}]},{id:"50067",doi:"10.5772/62301",title:"Urban Gardening: From Cost Avoidance to Profit Making — Example from Ljubljana, Slovenia",slug:"urban-gardening-from-cost-avoidance-to-profit-making-example-from-ljubljana-slovenia",totalDownloads:1783,totalCrossrefCites:2,totalDimensionsCites:4,book:{slug:"urban-agriculture",title:"Urban Agriculture",fullTitle:"Urban Agriculture"},signatures:"Matjaž Glavan, Majda Černič Istenič, Rozalija Cvejić and Marina\nPintar",authors:[{id:"61187",title:"Prof.",name:"Marina",middleName:null,surname:"Pintar",slug:"marina-pintar",fullName:"Marina Pintar"},{id:"82604",title:"Dr.",name:"Matjaž",middleName:null,surname:"Glavan",slug:"matjaz-glavan",fullName:"Matjaž Glavan"},{id:"178797",title:"Dr.",name:"Rozalija",middleName:null,surname:"Cvejić",slug:"rozalija-cvejic",fullName:"Rozalija Cvejić"},{id:"179170",title:"Prof.",name:"Majda",middleName:null,surname:"Černič Istenič",slug:"majda-cernic-istenic",fullName:"Majda Černič Istenič"}]},{id:"50109",doi:"10.5772/62302",title:"Water Quality Modeling and Control in Recirculating Aquaculture Systems",slug:"water-quality-modeling-and-control-in-recirculating-aquaculture-systems",totalDownloads:2168,totalCrossrefCites:1,totalDimensionsCites:3,book:{slug:"urban-agriculture",title:"Urban Agriculture",fullTitle:"Urban Agriculture"},signatures:"Marian Barbu, Emil Ceangă and Sergiu Caraman",authors:[{id:"21470",title:"Dr.",name:"Sergiu",middleName:null,surname:"Caraman",slug:"sergiu-caraman",fullName:"Sergiu Caraman"},{id:"22039",title:"Prof.",name:"Marian",middleName:null,surname:"Barbu",slug:"marian-barbu",fullName:"Marian Barbu"},{id:"180348",title:"Prof.",name:"Emil",middleName:null,surname:"Ceanga",slug:"emil-ceanga",fullName:"Emil Ceanga"}]}],mostDownloadedChaptersLast30Days:[{id:"70662",title:"Automation and Robotics Used in Hydroponic System",slug:"automation-and-robotics-used-in-hydroponic-system",totalDownloads:1544,totalCrossrefCites:0,totalDimensionsCites:1,book:{slug:"urban-horticulture-necessity-of-the-future",title:"Urban Horticulture",fullTitle:"Urban Horticulture - Necessity of the Future"},signatures:"Alejandro Isabel Luna Maldonado, Julia Mariana Márquez Reyes, Héctor Flores Breceda, Humberto Rodríguez Fuentes, Juan Antonio Vidales Contreras and Urbano Luna Maldonado",authors:[{id:"105774",title:"Prof.",name:"Alejandro Isabel",middleName:null,surname:"Luna Maldonado",slug:"alejandro-isabel-luna-maldonado",fullName:"Alejandro Isabel Luna Maldonado"},{id:"215230",title:"Dr.",name:"Juan Antonio",middleName:null,surname:"Vidales Contreras",slug:"juan-antonio-vidales-contreras",fullName:"Juan Antonio Vidales Contreras"},{id:"220744",title:"MSc.",name:"Héctor",middleName:null,surname:"Flores Breceda",slug:"hector-flores-breceda",fullName:"Héctor Flores Breceda"},{id:"252026",title:"Dr.",name:"Humberto",middleName:null,surname:"Rodríguez-Fuentes",slug:"humberto-rodriguez-fuentes",fullName:"Humberto Rodríguez-Fuentes"},{id:"299825",title:"Dr.",name:"Julia Mariana",middleName:null,surname:"Márquez Reyes",slug:"julia-mariana-marquez-reyes",fullName:"Julia Mariana Márquez Reyes"},{id:"303920",title:"Prof.",name:"Urbano",middleName:null,surname:"Luna Maldonado",slug:"urbano-luna-maldonado",fullName:"Urbano Luna Maldonado"}]},{id:"71186",title:"Application of Nanotechnology Solutions in Plants Fertilization",slug:"application-of-nanotechnology-solutions-in-plants-fertilization",totalDownloads:593,totalCrossrefCites:0,totalDimensionsCites:0,book:{slug:"urban-horticulture-necessity-of-the-future",title:"Urban Horticulture",fullTitle:"Urban Horticulture - Necessity of the Future"},signatures:"Daniela Predoi, Rodica V. Ghita, Simona Liliana Iconaru, Carmen Laura Cimpeanu and Stefania Mariana Raita",authors:[{id:"50919",title:"Dr.",name:"Rodica V.",middleName:null,surname:"Ghita",slug:"rodica-v.-ghita",fullName:"Rodica V. Ghita"},{id:"183930",title:"Prof.",name:"Daniela",middleName:null,surname:"Predoi",slug:"daniela-predoi",fullName:"Daniela Predoi"},{id:"313256",title:"Dr.",name:"Simona Liliana",middleName:null,surname:"Iconaru",slug:"simona-liliana-iconaru",fullName:"Simona Liliana Iconaru"},{id:"313258",title:"Dr.",name:"Carmen Laura",middleName:null,surname:"Cimpeanu",slug:"carmen-laura-cimpeanu",fullName:"Carmen Laura Cimpeanu"},{id:"313260",title:"Dr.",name:"Stefania Mariana",middleName:null,surname:"Raita",slug:"stefania-mariana-raita",fullName:"Stefania Mariana Raita"}]},{id:"70957",title:"Nutrients for Hydroponic Systems in Fruit Crops",slug:"nutrients-for-hydroponic-systems-in-fruit-crops",totalDownloads:587,totalCrossrefCites:1,totalDimensionsCites:1,book:{slug:"urban-horticulture-necessity-of-the-future",title:"Urban Horticulture",fullTitle:"Urban Horticulture - Necessity of the Future"},signatures:"Pramod Kumar and Simran Saini",authors:[{id:"253238",title:"Dr.",name:"Pramod",middleName:null,surname:"Kumar",slug:"pramod-kumar",fullName:"Pramod Kumar"},{id:"316834",title:"Ms.",name:"Simran",middleName:null,surname:"Saini",slug:"simran-saini",fullName:"Simran Saini"}]},{id:"50248",title:"Relationship between Population and Agricultural Land in Amasya",slug:"relationship-between-population-and-agricultural-land-in-amasya",totalDownloads:1530,totalCrossrefCites:0,totalDimensionsCites:2,book:{slug:"urban-agriculture",title:"Urban Agriculture",fullTitle:"Urban Agriculture"},signatures:"Mustafa Ergen",authors:[{id:"166961",title:"Dr.Ing.",name:"Mustafa",middleName:null,surname:"Ergen",slug:"mustafa-ergen",fullName:"Mustafa Ergen"}]},{id:"50063",title:"Urban Agriculture Case Studies in Central Texas: From the Ground to the Rooftop",slug:"urban-agriculture-case-studies-in-central-texas-from-the-ground-to-the-rooftop",totalDownloads:1730,totalCrossrefCites:0,totalDimensionsCites:0,book:{slug:"urban-agriculture",title:"Urban Agriculture",fullTitle:"Urban Agriculture"},signatures:"Bruce D. Dvorak and Ahmed K. Ali",authors:[{id:"178373",title:"Dr.",name:"Ahmed K.",middleName:"Kamal",surname:"Ali",slug:"ahmed-k.-ali",fullName:"Ahmed K. Ali"},{id:"179542",title:"Prof.",name:"Bruce",middleName:null,surname:"Dvorak",slug:"bruce-dvorak",fullName:"Bruce Dvorak"}]},{id:"71024",title:"Implication of Urban Agriculture and Vertical Farming for Future Sustainability",slug:"implication-of-urban-agriculture-and-vertical-farming-for-future-sustainability",totalDownloads:670,totalCrossrefCites:0,totalDimensionsCites:0,book:{slug:"urban-horticulture-necessity-of-the-future",title:"Urban Horticulture",fullTitle:"Urban Horticulture - Necessity of the Future"},signatures:"Anwesha Chatterjee, Sanjit Debnath and Harshata Pal",authors:[{id:"312477",title:"Dr.",name:"Harshata",middleName:null,surname:"Pal",slug:"harshata-pal",fullName:"Harshata Pal"},{id:"316680",title:"Dr.",name:"Anwesha",middleName:null,surname:"Chatterjee",slug:"anwesha-chatterjee",fullName:"Anwesha Chatterjee"},{id:"316681",title:"Dr.",name:"Sanjit",middleName:null,surname:"Debnath",slug:"sanjit-debnath",fullName:"Sanjit Debnath"}]},{id:"67079",title:"Introductory Chapter: Agricultural Economics",slug:"introductory-chapter-agricultural-economics",totalDownloads:601,totalCrossrefCites:0,totalDimensionsCites:0,book:{slug:"agricultural-economics-current-issues",title:"Agricultural Economics",fullTitle:"Agricultural Economics - Current Issues"},signatures:"Surendra N. Kulshreshtha",authors:[{id:"37057",title:"Dr.",name:"Surendra N.",middleName:null,surname:"Kulshreshtha",slug:"surendra-n.-kulshreshtha",fullName:"Surendra N. Kulshreshtha"}]},{id:"50067",title:"Urban Gardening: From Cost Avoidance to Profit Making — Example from Ljubljana, Slovenia",slug:"urban-gardening-from-cost-avoidance-to-profit-making-example-from-ljubljana-slovenia",totalDownloads:1781,totalCrossrefCites:2,totalDimensionsCites:4,book:{slug:"urban-agriculture",title:"Urban Agriculture",fullTitle:"Urban Agriculture"},signatures:"Matjaž Glavan, Majda Černič Istenič, Rozalija Cvejić and Marina\nPintar",authors:[{id:"61187",title:"Prof.",name:"Marina",middleName:null,surname:"Pintar",slug:"marina-pintar",fullName:"Marina Pintar"},{id:"82604",title:"Dr.",name:"Matjaž",middleName:null,surname:"Glavan",slug:"matjaz-glavan",fullName:"Matjaž Glavan"},{id:"178797",title:"Dr.",name:"Rozalija",middleName:null,surname:"Cvejić",slug:"rozalija-cvejic",fullName:"Rozalija Cvejić"},{id:"179170",title:"Prof.",name:"Majda",middleName:null,surname:"Černič Istenič",slug:"majda-cernic-istenic",fullName:"Majda Černič Istenič"}]},{id:"50109",title:"Water Quality Modeling and Control in Recirculating Aquaculture Systems",slug:"water-quality-modeling-and-control-in-recirculating-aquaculture-systems",totalDownloads:2165,totalCrossrefCites:1,totalDimensionsCites:3,book:{slug:"urban-agriculture",title:"Urban Agriculture",fullTitle:"Urban Agriculture"},signatures:"Marian Barbu, Emil Ceangă and Sergiu Caraman",authors:[{id:"21470",title:"Dr.",name:"Sergiu",middleName:null,surname:"Caraman",slug:"sergiu-caraman",fullName:"Sergiu Caraman"},{id:"22039",title:"Prof.",name:"Marian",middleName:null,surname:"Barbu",slug:"marian-barbu",fullName:"Marian Barbu"},{id:"180348",title:"Prof.",name:"Emil",middleName:null,surname:"Ceanga",slug:"emil-ceanga",fullName:"Emil Ceanga"}]},{id:"72163",title:"Nutritive Solutions Formulated from Organic Fertilizers",slug:"nutritive-solutions-formulated-from-organic-fertilizers",totalDownloads:299,totalCrossrefCites:0,totalDimensionsCites:0,book:{slug:"urban-horticulture-necessity-of-the-future",title:"Urban Horticulture",fullTitle:"Urban Horticulture - Necessity of the Future"},signatures:"Juan Carlos Rodríguez Ortiz",authors:[{id:"304656",title:"Dr.",name:"Juan Carlos",middleName:null,surname:"Rodríguez Ortiz",slug:"juan-carlos-rodriguez-ortiz",fullName:"Juan Carlos Rodríguez Ortiz"}]}],onlineFirstChaptersFilter:{topicSlug:"urban-agriculture",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/38321/leandro-lima",hash:"",query:{},params:{id:"38321",slug:"leandro-lima"},fullPath:"/profiles/38321/leandro-lima",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)}()