Thomasenkuhn4056

An overview of C-S bond cleavage reactions with stoichiometric transition-metal reagents is briefly given. Theoretical studies on the reactivity of carbon-sulfur bonds by DFT calculations are also discussed.Nanoparticles (NPs) used for targeted delivery purposes are rapidly gaining importance in diagnostic and therapeutic fields. These agents have been studied extensively so far to reveal their optimal physicochemical properties including the effects of ligands and their density on the surface of NPs. This article was conducted through a computational approach (all-atom molecular dynamics simulations) to predict the stability of NPs based on a poly-lactic-co-glycolic acid (PLGA) hydrophobic core with a poly-ethylene glycol (PEG) hydrophilic shell and varying numbers of riboflavin (RF) molecules as ligands. Depending on the molecular weight of the polymers, the most stable composition of NPs was achieved at 20 wt% and 10 wt% PLGA-PEG-RF for PLGA3kDa-PEG2kDa and PLGA4.5kDa-PEG2kDa polymers, respectively. According to the simulations, riboflavin molecules were located on the surface of the NPs, which would indicate that riboflavin-bound PLGA-PEG NPs could be efficiently utilized for active targeting purposes. To scrutinize the simulation results, NPs with riboflavin ligands were synthesized and put into in vitro experiments. Outstandingly, the empirical outcomes revealed that the hydrodynamic sizes of NPs also met minimum points at 20 and 10 wt% for PLGA3kDa-PEG2kDa and PLGA4.5kDa-PEG2kDa, respectively. Moreover, similar trends in the gyration radius as a function of riboflavin content were observed in the simulation analysis and the experimental results, which would indicate that the method of molecular dynamics (MD) simulation is a reliable mathematical technique and could be applied for predicting the physicochemical properties of NPs.The nature and distribution of charged residues on the surface of proteins play a vital role in determining the binding affinity, selectivity and kinetics of association to ligands. When it comes to DNA-binding domains (DBDs), these functional features manifest as anisotropic distribution of positively charged residues on the protein surface driven by the requirement to bind DNA, a highly negatively charged polymer. In this work, we compare the thermodynamic behavior of nine different proteins belonging to three families - LacR, engrailed and Brk - some of which are disordered in solution in the absence of DNA. Combining detailed electrostatic calculations and statistical mechanical modeling of folding landscapes at different distances and relative orientations with respect to DNA, we show that non-specific electrostatic interactions between the protein and DNA can promote structural transitions in DBDs. Such quinary interactions that are strictly agnostic to the DNA sequence induce varied behaviors including folding of disordered domains, partial unfolding of ordered proteins and (de-)population of intermediate states. Our work highlights that the folding landscape of proteins can be tuned as a function of distance from DNA and hints at possible reasons for DBDs exhibiting complex kinetic-thermodynamic behaviors in the absence of DNA.The hammer impact test is a conventional modal analysis technique in large-scale structures. It possesses efficient capability in the excitation of any structure within a wide range of frequencies and thus, this technique can be a good method to identify the dynamics of any structure. Here, we have implemented this method on nano-scale structures using molecular dynamics simulations. For convenience, we used a carbon nanotube (CNT) that showed complicated behavior due to van der Waals (vdW) interactions with a graphene sheet. The graphene sheet represents the vdW interactions of the CNT with its surroundings, which is an important distinction between the phenomena at the nano-scale. The variations in the fundamental natural frequency and quality factor of the CNT with different strengths of the vdW interactions are explored. For this purpose, the distance between the CNT and graphene is used as the tuning parameter. The results of the hammer impact tests were compared and matched to those obtained with a well. These results can be used in the design of novel experimental procedures for the evaluation of the vibrational properties of nanostructures.Lithium (Li) metal is a promising anode material for next-generation batteries because of its low standard reduction potential (-3.04 V vs. SHE) and high specific capacity (3860 mA h g-1). However, it is still challenging to directly use Li metal as anode material in commercial batteries because of unstable Li dendrite formation and accumulated solid-electrolyte interphase. Possible methods that can suppress the unwanted formation of Li dendrites are (i) by increasing the electrode surface area and (ii) formation of porosity for confining Li. Here, we tested microporous ( less then 2 nm) carbon and mesoporous (2-50 nm) carbon as host materials for the Li metal anode to avoid their degradation during cycling of lithium metal batteries (LMBs). Mesoporous carbon was more effective than microporous carbon as a host material to confine the Li metal and the lifetime of mesoporous carbon was more than twice as long as those of the Cu foil and microporous carbon. After confirmed better anode performance of mesoporous carbon host material, we applied Li-plated mesoporous carbon as an anode in a lithium-sulfur battery (Li-S) full cell. This research work suggests that mesopores, in spite of their low specific surface area, are better than micropores in stabilizing the Li metal and that a mesoporous host material can be applied to Li metal anodes for use in next-generation battery applications.The development of flexible all-solid-state rechargeable Zn-air batteries (FS-ZABs) for wearable applications faces challenges from the balance between performance and flexibility of the battery; efficient cathode catalyst and reasonable electrode construction design are key factors. Herein, a low-cost pollen derived N,S co-doped porous carbon decorated with Co9S8/Fe3S4 nanoparticle hybrids (Co-Fe-S@NSRPC) has been synthesized. Owing to the active Co9S8/Fe3S4 nanoparticles, N,S co-doping, and large specific area of the pollen derived porous carbon matrix, the Co-Fe-S@NSRPC composite exhibits an excellent bifunctional catalytic activity with a small potential gap (ΔE = 0.80 V) between the half-wave potential for the ORR (0.80 V) and the potential at 10 mA cm-2 for the OER (1.60 V), and endows a liquid Zn-air battery with a high power density of 138 mW cm-2, a larger specific capacity of 891 mA h g-1 and a stable rechargeability of up to 331 cycles. Based on the Co-Fe-S@NSRPC cathode catalyst, a 2D coplanar FS-ZAB has been fabricated with specially designed parallel narrow strip electrodes alternately arrayed on a polyacrylamide polyacrylic acid copolymer hydrogel solid electrolyte. The presented FS-ZAB exhibits excellent battery performance with high open-circuit-voltage (1.415 V), competitive peak power density (78 mW cm-2), large specific capacity (785 mA h g-1) and stable rechargeability (150 cycles), offers robust flexibility to maintain stable charge/discharge capacity under different bending deformations, and provides convenient coplanar integrability to realize parallel or series connection of multiple cells in a relatively small area.The discovery of peculiar quasi-liquid layers on ice surfaces marks a major breakthrough in ice-related sciences, as the facile tuning of the reactions and morphologies of substances in contact with these layers make ice-assisted chemistry a low-cost, environmentally benign, and ubiquitous methodology for the synthesis of nanomaterials with improved functionality. Ice-templated synthesis of porous materials offers the appealing features of rapid self-organization and remarkable property changes arising from confinement effects and affords materials that have found a diverse range of applications such as batteries, supercapacitors, and gas separation. Moreover, much attention has been drawn to the acceleration of chemical reactions and transformations on the ice surface due to the freeze concentration effect, fast self-diffusion of surface water, and modulated surface potential energy. Some of these results are related to the accumulation of inorganic contaminants in glaciers and the blockage of natural gas pipelines. As an emerging theme in nanomaterial design, the dimension-controlled synthesis of hybrid materials with unprecedentedly enhanced properties on ice surfaces has attracted much interest. However, a deep understanding of quasi-liquid layer characteristics (and hence, the development of cutting-edge analytical technologies with high surface sensitivity) is required to achieve the current goal of ice-assisted chemistry, namely the preparation of tailor-made materials with the desired properties.Interstratified 2D nanohybrids of chromium hydroxide-molybdenum disulfide with improved electrode functionality are synthesized by the self-assembly of anionic monolayered MoS2 nanosheets with cationic chromium hydroxide nanoclusters. The intercalative hybridization of MoS2 with chromium hydroxide nanoclusters leads to a significant increase of basal spacing as well as to the formation of an open porous stacking structure. This is the first example of metal hydroxide nanocluster-pillared transition metal dichalcogenide (TMD) hybrid materials. Menadione manufacturer According to extended X-ray absorption fine structure analysis, open tetrameric chromium hydroxide nanoclusters are stabilized in-between metallic 1T'-MoS2 monolayers. In comparison with the pristine MoS2 material, the chromium hydroxide-pillared molybdenum disulfide nanohybrids show remarkably improved charge storage capacity with excellent rate performance for lithium ion batteries, highlighting the beneficial effect of pillaring with metal hydroxides on the electrode performance of MoS2. The improvement of electrode functionality upon hybridization is attributable to the increase of basal spacing, the stabilization of metallic 1T'-MoS2 content, the improvement of charge transfer kinetics, and the stabilization of the open porous structure upon electrochemical cycling. The present study clearly demonstrates that an electrostatically-driven self-assembly between exfoliated TMD nanosheets and cationic inorganic nanoclusters can provide an effective way of synthesizing heterostructured hybrid electrode materials with improved performance.As a two-dimensional layered material with a structure analogous to that of graphene, molybdenum disulfide (MoS2) holds great promise in sodium-ion batteries (SIBs). However, recent research findings have revealed some disadvantages in two-dimensional (2D) materials such as poor interlayer conductivity and structural instability, resulting in poor rate performance and short cycle life for SIBs. Herein, we designed MoS2 nanoflowers with an ultra-wide spacing interlayer (W-MoS2/C) anchored on special double carbon tubes to construct three-dimensional (3D) nanostructures. When tested as an anode material in a SIB, the as-prepared CNT@NCT@W-MoS2/C sample achieves high capacities (530 and 230 mA h g-1 at current densities of 0.1 and 2 A g-1, respectively). Density functional theory (DFT) calculations demonstrate that the ultra-wide spacing MoS2/C structure is beneficial for the chemical adsorption of sodium ions and facilitates redox reactions. The wide interlayer spacing and the presence of an intermediate carbon layer provide a rapid diffusion channel for ions and offer a free space for volume expansion of the electrode material.