• Dueholm Pedersen posted an update 5 hours, 58 minutes ago

    Finally, the Ni deposition rate predicted using the deposition constant (Ddep) was found to be much higher than its surface diffusion rate predicted using Ds for Ni(111) and Ni(110), which quantitatively verified the overgrowth along the 111 and 110 directions to produce the branched Ni nanostructures.In this study, we compare the results for vibrational, reorientational and hydrogen bond dynamics of ethanol in water and in hexane across the whole concentration range. Water and hexane are both commonly used as solvents, but so far, it has been unclear to what extent they modify the solute dynamics. Ethanol is chosen as the solute because it is an aliphatic molecule that is miscibile with both solvents. It is known that ethanol forms micelle-like domains in water and cyclic clusters resembling loops in hexane. This structural micro-heterogeneity is well known both in experiments and in simulations. The main question we raise here is is there a signature of micro-heterogeneity in the dynamical quantities of ethanol? We focus on quantities such as the vibrational spectra, the reorientational correlation functions, the self-diffusion coefficients, the ethanol-ethanol hydrogen bond correlation functions and the corresponding hydrogen bond histograms. For the first time ever, we compute the van Hove functions to reveal the dynamical variations of spatial correlations in these systems. All these results complement each other and provide a unifying dynamical description of ethanol in binary mixtures.With the advancement of medical research, the source and preparation of biological materials have gradually attracted attention. Hydrogels prepared from natural polysaccharides have been extensively applied in the medical field. The biocompatibility, excellent degradability and low toxicity of chitosan have favored the use of chitosan hydrogels as prospective carriers for drug delivery. Special chitosan hydrogels that effectively release target drugs based on different environmental stimuli have also been developed. This article reviews recent research progress in the development of chemical and physical chitosan hydrogels for drug delivery. In particular, preparation methods together with the chemical and physical properties of chitosan hydrogels are summarized. We also discuss multiple mechanisms of drug release from chitosan hydrogels. Finally, we highlight the future prospects of chitosan hydrogels in medical research.A fundamental link between conceptual density functional theory and statistical thermodynamics is herein drawn, showing that intermolecular electrostatic interactions can be understood in terms of effective work and heat exchange. From a more detailed analysis of the heat exchange in a perturbation theory framework, an associated entropy can be subsequently derived, which appears to be a suitable descriptor for the local polarisability of the electron density. A general rule of thumb is evidenced the more the perturbation can be spread, both through space and among the excited states, the larger the heat exchange and entropy.Molecular level insights on protein-ionic liquid (P-IL) interactions are beneficial for assessing protein stability, binding and dynamics. In the present work, interactions of ILs, namely, 1-butyl 3-methylimidazolium methyl sulfate (IL1), 1-butyl 3-methylimidazolium octyl sulfate (IL2) and 1-butyl 3-methylimidazolium chloride (IL3) with hen egg white lysozyme (HEWL) protein were investigated using solution-state nuclear magnetic resonance (NMR) spectroscopy. To ascertain the binding and dynamics from the perspective of both protein and IL, various ligand based NMR approaches such as selective and non-selective nuclear spin-relaxation (R1SEL and R1NS), saturation transfer difference (STD), difference of inversion recovery rate with and without target irradiation (DIRECTION), 35Cl line-shape and spin-relaxation, and protein back bone amide chemical shift perturbations (CSPs) from 1H-15N HSQC were utilized. Among the ILs investigated, IL2 experiences significant interaction relative to those of IL1 and IL3, as revealed by the combined R1SEL and R1NS analysis, which is further supported by STD NMR. Menadione order CSP analyses of 1H-15N HSQC spectra of aqueous P-IL mixtures enabled to identify the potential binding sites of ILs with HEWL. Whereas, 15N longitudinal (R1) and transverse (R2) spin-relaxation rates and 15N1H heteronuclear nuclear Overhauser effect (hetNOE) data subjected to the model free analysis for IL2 yielded the rotational correlation times and order parameters of various residues of HEWL. Furthermore, the results could discern the nature of interactions between studied ILs and HEWL in terms of specific and non-specific interactions.We present novel experimental results of negative ion formation of halothane (C2HBrClF3) upon electron transfer from hyperthermal neutral potassium atoms (K°) in the collision energy range of 8-1000 eV. The experiments were performed in a crossed molecular beam setup allowing a comprehensive analysis of the time-of-flight (TOF) mass negative ions fragmentation pattern and a detailed knowledge of the collision dynamics in the energy range investigated. Such TOF mass spectra data show that the only negative ions formed are Br-, Cl- and F-, with a strong energy dependence in the low-energy collision region, with the bromine anion being the most abundant and sole fragment at the lowest collision energy probed. In addition, potassium cation (K+) energy loss spectra in the forward scattering direction were obtained in a hemispherical energy analyser at different K° impact energies. In order to support our experimental findings, ab initio quantum chemical calculations have been performed to help interpret the role of the electronic structure of halothane. Potential energy curves were obtained along the C-X (X = Br, Cl) coordinate to lend support to the dissociation processes yielding anion formation.To find potential alkaline-earth metal-doped aromatic superconductors and clarify the origin of superconductivity in metal-doped phenanthrene (PHN) systems, we have systematically investigated the crystal and electronic structures of bivalent metal (Mg, Ca, Sr and Ba)-doped PHNs by first-principles calculations. The results show that only Ba1.5PHN can satisfy the conditions of both thermodynamic stability and metallization. We predicted that Ba1.5PHN is superconducting with the critical temperature of 5.3 K. Based on the metal atomic radius and electronegativity and combined with monovalent metal- and trivalent metal-doped PHNs, the relations among charge transfer, metallization, and superconductivity were analyzed. The results indicate that the electronegativity of the metal element rather than the atomic radius is predominant in the charge transfer and superconductivity of metal-doped phenanthrene.