Earlier the original source of phosphorus (P) fertilizer was bones; as time passes, the supply of P fertilizer will get exhausted. Today, rock phosphate is the only raw material in the form of P fertilizers. There are two types of rock phosphates: igneous and sedimentary; both have the same phosphate mineral, i.e., calcium phosphate of apatite group. The general formula for pure rock phosphate is Ca10(PO4)6(X)2, where X is F−, OH− or Cl−. These minerals are called apatites. The most common rock phosphate mined is fluorapatite, which contains impurities like CO3, Na and Mg. Carbonate-fluorapatite (francolite) is primary apatite mineral in the majority of phosphate rocks. The high reactivity of some phosphate rocks is due to the occurrence of francolite. The major deposits are found in the US followed by China, Morocco and Russia. The US produced about 33% of the world’s rock phosphate, although nearly 50% of the world reserves are in Morocco. P fertilizers are produced from either acid-treated or heat-treated rock phosphate to break the apatite bond and to increase the water soluble P content. There are many commercially available P fertilizers like rock phosphate, phosphoric acid, calcium orthophosphates, ammonium phosphates, ammonium polyphosphate and nitric phosphates.
Part of the book: Phosphorus
Filariasis is one of the most debilitating tropical neglected diseases with high morbidity rate and less rate of mortality with various clinical symptoms. According to the World Health Organization (WHO) reports, about 120 million people from 81 countries are infected at present, and an estimated 1.34 billion people live in areas endemic to filariasis and are at risk of infection. Currently available drugs are only effective against the larval stage of the worms with side effects, and their repetitive use gives rise to drug resistance. Till date, no effective vaccine is available for the treatment of filariasis; to fulfill this need, new drug development becomes the priority for the researchers. This chapter reviews different synthetic and natural origin drugs, drug targets, and use of bioinformatics to discover new antifilarial agents which can control this debilitating disease, including the types of filariasis, their prevalence, and eradication programs which are discussed.
Part of the book: Helminthiasis