Short histidine-rich peptides could serve as novel activatable vectors for delivering cytotoxic payloads to tumor and neovasculature cells. This explorative study reports preliminary results showing that zinc ions, which are found in elevated levels at neovasculature sites, can trigger the intracellular delivery of a short antimicrobial peptide when conjugated to a histidine-rich peptide through a disulfide bond. The importance of exofacial thiols in the mode of action of these disulfide-linked conjugates is also shown. Copyright © 2020 American Chemical Society.To meet the increasing need for clean combustion, improve the combustion efficiency of fuels, and reduce the pollutants produced in the combustion process, it is necessary to systematically study the combustion of hydrocarbon fuels. An accurate and detailed chemical kinetic model is an important prerequisite for understanding the combustion performance of hydrocarbon fuels and studying complex chemical reaction networks. Therefore, based on ReaxGen, new detailed mechanisms for the low-temperature combustion of n-nonane are proposed and verified in detail in this study. Meanwhile, some international mainstream combustion models such as the LLNL model and the JetSurf 2.0 model are compared with ours, showing that the proposed new mechanisms can better predict the ignition delay combustion characteristics of n-nonane, and they also hold in a wide range of conditions. https://www.selleckchem.com/products/gsk3368715.html In addition, the numerical simulation results of the concentration curve calculated for the new mechanisms, especially Model v2, are in good agreement with the experimental data, and the mechanisms can reproduce the performance of the negative-temperature-coefficient behavior toward n-nonane ignition. The numerical simulation results of the laminar flame propagation velocity varying with the equivalence ratio are also in good agreement with the available experimental data. Finally, the ignition delay sensitivity of n-nonane is analyzed by the sensitivity analysis method; the key reactions affecting the ignition mechanism are investigated; and the reaction path analysis is conducted to better understand the models' predicted performance. In a word, the new mechanisms are helpful to understand the ignition properties of large hydrocarbon fuels for high-speed aircrafts. Copyright © 2020 American Chemical Society.The pH dependence of the trypsin-catalyzed hydrolysis of N-α-benzyloxycarbonyl-l-lysine p-nitroanilide has been studied at 25 °C. k cat/K M was maximal at alkaline pH values but decreased with decreasing pH. k cat/K M was dependent on free enzyme pK a values of 6.75 ± 0.09 and 4.10 ± 0.13, which were assigned to the ionization of the active site histidine-57 and aspartate-189, respectively. Protonation of either group abolished catalytic activity. k cat is shown to equal the acylation rate constant k 2 over the pH range studied. k 2 decreased on the protonation of two groups with pK a values of 4.81 ± 0.15 and 4.23 ± 0.19. We assign the pK a of 4.23 to the ionization of the aspartate-189 residue and the pK a of 4.81 to the oxyanion of the tetrahedral intermediate formed during acylation. We conclude that during acylation, breakdown of the catalytic tetrahedral intermediate is rate-limiting and that there is a strong interaction between the imidazolium ion of histidine-57 and the oxyanion of the catalytic tetrahedral intermediate, which perturbs their pK a values. From the pH dependence of k 3, we conclude that deacylation depends on a pK a of 6.41 ± 0.22 and that the ionization of the carboxylate group of aspartate-189 does not have a significant effect on the rate of deacylation (k 3). A catalytic mechanism is proposed to explain the pH dependence of catalysis. Copyright © 2020 American Chemical Society.In this paper, we report on the unexplored reaction mechanisms of bimolecular homolytic substitution (SH2) between GeH3 radicals and the nitrogen atom of NF3. The SH2 reactions are studied both experimentally and theoretically with ab initio and density functional theory (DFT) calculations. The experimental results of X-ray irradiation of mixtures of GeH4 and NF3 show the formation of GeH3-NF2 and GeH3-F. The trend of product yields as a function of the increase in GeH4 partial pressure in the irradiated mixtures evidences the predominant role of GeH3 radicals. Particularly, the SH2 mechanism can be hypothesized for the reaction between GeH3 radicals and NF3 molecules leading to GeH3-NF2. This mechanism is further confirmed by the increase in GeH3-NF2 yield observed if O2 is added, as a radical scavenger, to the reaction mixture. In agreement with the experimental data, from the calculations performed at the CCSD(T) and G3B3 levels of theory, we observe that the GeH3-NF2 product actually occurs from a bimolecular homolytic substitution by the GeH3 radical, which attacks the N atom of NF3, and this reaction is in competition with the fluorine abstraction reaction leading to GeH3F, even if other mechanisms may be involved in the formation of this product. Copyright © 2020 American Chemical Society.Forest is one of nature's most generous gifts to human beings, providing materials and shelters for all living beings with over 30% global land coverage. Apart from being sustainable, biodegradable, and renewable, wood is also extremely fascinating from the application aspect, with numerous advantages including hierarchical and macroporous structure, excellent mechanical performance, and versatile chemistry. The macroporous structure of wood is comprised of numerous long, partially aligned channels along the growth direction. This structure is suitable for a range of emerging applications, especially as a separation/membrane material. In this research, the potentiality of Gingko biloba (Gb) wood in the remediation of wastewater, contaminated with methylene blue (MB), a dye found in the industrial waters, was investigated. We report a macroporous, three-dimensional (3D) Gb-wood membrane decorated with palladium nanoparticles (Pd NPs) for efficient wastewater treatment. The efficiency of the Pd NPs/Gb-wood membrane to remove MB from a flowing aqueous solution was demonstrated.