Utilization of a Novel Chitosan/Clay/Biochar Nanobiocomposite for Immobilization of Heavy Metals in Acid Soil Environment

An organic–inorganic composite of chitosan, nanoclay, and biochar (named as MTCB) was chosen to develop a bionanocomposite to simultaneously immobilize Cu, Pb, and Zn metal ions within the contaminated soil and water environments. The composite material was structurally and chemically characterized with the XRD, TEM, SEM, BET, and FT-IR techniques. XRD and TEM results revealed that a mixed exfoliated/intercalated morphology was formed upon addition of small amounts of nanoclay (5% by weight). Batch adsorption experiments showed that the adsorption capacity of MTCB for Cu2+, Pb2+, and Zn2+ were much higher than that of the pristine biochar sample (121.5, 336, and 134.6 mg g−1 for Cu2+, Pb2+, and Zn2+, respectively). The adsorption isotherm for Cu2+ and Zn2+ fitted satisfactorily to a Freundlich model while the isotherm of Pb2+ was best represented by a Temkin model. That the adsorption capacity increased with increasing temperature is indicative of the endothermic nature of the adsorption process. According to the FTIR analysis, the main mechanism involved in immobilization of metals is binding with –NH2 groups. Results from this study indicated that modification of biochar by chitosan/clay nanocomposite enhances its potential capacity for immobilization of heavy metals, rendering the bionanocomposite into an efficient heavy metal sorbent in mine-impacted acidic waters and soils

Phosphorodiamidates as a Promising New Phosphate Prodrug Motif for Antiviral Drug Discovery: Application to Anti-HCV Agents

We herein report phosphorodiamidates as a significant new phosphate prodrug motif. Sixty-seven phosphorodiamidates are reported of two 6-O-alkyl 2′-C-methyl guanosines, with significant variation in the diamidate structure. Both symmetrical and asymmetric phosphorodiamidates are reported, derived from various esterified amino acids, both d and l, and also from various simple amines. All of the compounds were evaluated versus hepatitis C virus in replicon assay, and nanomolar activity levels were observed. Many compounds were noncytotoxic at 100 μM, leading to high antiviral selectivities. The agents are stable in acidic, neutral, and moderately basic media and in selected biological media but show efficient processing by carboxypeptidases and efficiently yield the free nucleoside monophosphate in cells. On the basis of in vitro data, eight leads were selected for additional in vivo evaluation, with the intent of selecting one candidate for progression toward clinical studies. This phosphorodiamidate prodrug method may have broad application outside of HCV and antivirals as it offers many of the advantages of phosphoramidate ProTides but without the chirality issues present in most cases

Sports-Related Injuries of the Anterior Segment

Sports-related eye injury is a significant cause of morbidity and disability and accounts for a significant proportion of ocular trauma, especially in the young. Although some sports-related ocular injuries can be self-resolving and require little to no intervention, many other injuries have long-term sequelae that require extensive treatment and follow-up. A thorough evaluation of the mechanism of and circumstances surrounding the ocular injury is important to guide further management of the case. Blunt trauma has a significantly different pathophysiologic process compared to trauma by a sharp object, and the evaluation of the injury should be cognizant of the ocular trauma expected. The conjunctiva is most frequently involved in sports-related ocular injuries, and the nature of the conjunctival injury can often indicate involvement of other potential ocular structures. Examples of other anterior segment injuries that can result from sports-related ocular trauma include structural or functional damage to the cornea, iris injury leading to iris prolapse or laceration, ciliary body injury resulting in ciliary body detachment, lens injury resulting in cataract or subluxation/dislocation of the lens, and traumatic glaucoma. In this chapter, we provide a comprehensive review of the pathogenesis, clinical findings, treatment options, and prognosis of sports-related injuries of the anterior segment