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  • Hardin Greer posted an update 3 weeks, 1 day ago

    The antioxidant and antimicrobial potential of NPs revealed that chemically synthesized NPs have better antimicrobial capability, while the antioxidative activities were better for green-synthesized NPs. However, the low yield, high ion disassociation, and waste (unreacted metal) production in the green synthesis of CdO NPs increase the risk of contamination to biosphere. Both types of NPs did not affect the seed germination of Dodonaea viscosa. However, chemically synthesized NPs were less toxic on plant morphological response. The study concludes that the chemically synthesized CdO NPs have better morphology, significant antimicrobial activity, and less toxicity to plant species compared to green-synthesized NPs. Moreover, during the green synthesis, unreacted metals are drained, which causes contamination to the ecosystem. Copyright © 2020 American Chemical Society.The fabrication of silver nanoparticles (Ag NPs) with different sizes by microwave (MW)-assisted synthesis is presented. The fast heating of the MW technique, combined with the possibility to thermally quench the reactions, enabled us to capture snapshots of nucleation and growth processes difficult to accomplish in other techniques. The Ag NPs were synthesized using poly(vinylpyrrolidone) (PVP) through a polyol approach. The effects of the reaction time, the reaction temperatures, and the silver precursor concentration were investigated. The influence of agitation, the PVP concentration, and the initial conditions of the silver precursor was also studied. It is found that at very short reaction times and at low temperatures, polyhedral plates are formed with sizes ca. 300 nm and large polydispersity. However, by increasing the time or the temperature, a size and shape refinement is observed resulting in 10 nm spherical NPs with low polydispersity. Mechanistic insights are provided based on the observations extracted from transmission electron microscopy (TEM) and ultraviolet-visible spectroscopy (UV-vis). A formation mechanism starting from kinetically favored silver polyhedral plates to thermodynamically favored spherical nanoparticles is proposed. Understanding these effects allowed us to control the particle size and the tuning of Ag NPs on-demand. Moreover, the reproducibility and scalability of the process and the long-term stability of the NPs in aqueous solutions are demonstrated. Finally, we provide a recommendation regarding the use of fresh PVP as a capping and stabilizing agent. Copyright © 2020 American Chemical Society.Kinesin is a typical molecular motor that can step processively on microtubules powered by hydrolysis of adenosine triphosphate (ATP) molecules, playing a critical role in intracellular transports. Its dynamical properties such as its velocity, stepping ratio, run length, dissociation rate, etc. as well as the load dependencies of these quantities have been well documented through single-molecule experimental methods. In particular, the run length shows a dramatic asymmetry with respect to the direction of the load, and the dissociation rate exhibits a slip-catch-slip bond behavior under the backward load. Here, an analytic theory was provided for the dynamics of kinesin motors under both forward and backward loads, explaining consistently and quantitatively the diverse available experimental results. Copyright © 2020 American Chemical Society.We analyzed the extracellular proteome of colistin-resistant Korean Acinetobacter baumannii (KAB) strains to identify proteome profiles that can be used to characterize extensively drug-resistant KAB strains. Four colistin-resistant KAB strains with colistin resistance associated with point mutations in pmrB and pmrC genes were analyzed. Analysis of the extracellular proteome of these strains revealed the presence of 506 induced common proteins, which were hence considered as the core extracellular proteome. Class C ADC-30 and class D OXA-23 β-lactamases were abundantly induced in these strains. Porins (CarO and CarO-like porin), outer membrane proteins (OmpH and BamABDE), transport protein (AdeK), receptor (TonB), and several proteins of unknown function were among the specifically induced proteins. Based on the sequence homology analysis of proteins from the core proteome and those of other A. baumannii strains and pathogenic bacterial species as well as further in silico screening, we propose that CarO-like porin is an A. baumannii-specific protein and that two tryptic peptides that originate from CarO-like porin detected by tandem mass spectrometry are peptide makers of this protein. Copyright © 2020 American Chemical Society.The cosmetic industry provides a wide variety of shampoos to treat dandruff, containing insoluble ingredients such as Zn pyrithione. However, the solubility of this active ingredient is quite limited in both water and oil media; thus, antidandruff formulations must include a large amount of chemically synthesized stabilizing ingredients to avoid their precipitation. In this work, the stabilization of Zn pyrithione in O/W emulsions using a biosurfactant (BS) extract and Tween 80 is studied. The study includes an incomplete factorial design based on the tea tree oil/water ratio and both surfactant and biosurfactant concentrations. FINO2 clinical trial The formulations are characterized in terms of particle size, stability after 30 days, and solubility of Zn pyrithione. The formulation that provided the most favorable results contains Tween 80 (5%) and BS extract (2.5%), with an O/W ratio of 0.01. This provides the smallest particle size (40.5 μm), good stability after 30 days (91.0%), and the highest solubility of Zn pyrithione (59%). The results obtained enable the use of the combination of BS extract and Tween 80 as bio/surfactants of antidandruff shampoo formulations, along with another antiseptic agent such as tea tree oil. Furthermore, this is the first work where a biosurfactant is considered to be a stabilizing agent in antidandruff formulations. Copyright © 2020 American Chemical Society.Studies were made on the influence of temperature and oxygen to carbon ratio (the O/C ratio) on the properties of particles during water coal slurry gasification by taking a new-type coal-water slurry gasifier as the thermal experiment platform, coal-water slurry as a gasification material, and oxygen as the oxidant. The results show that the higher the gasification temperature, the more spherical particles are generated, the higher the content of Na, Fe, and S on the particle surface, and the greater the mass percentage of fine particles. With increase in the O/C ratio, the production of fine particles also increases, while the carbon content of the particles decreases. When the O/C ratio is 1.1, fine particles mainly exist in the form of aggregates; the O/C ratio has little influence on the contents of the particle surface, such as Na, Al, Si, Fe, and S. The effect of the O/C ratio on particle size distribution is most obvious when the ratio is 1 the fine particles are the most prevalent and the coarse particles are the fewest.

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