Significance of Mg doped LiMn2O4 spinels as attractive 4 V cathode materials for use in lithium batteries

LiMn₂O₄ spinel is one of the most promising cathode materials for lithium-ion batteries because of its cheapness and eco-friendliness. Due to Jahn-Teller distortion, the capacity fades, however, upon repeated cycling. Attempts are being made to improve the cycle life of the spinel by substitution of manganese with other cations. In this paper we report the effect of partial substitution of manganese by Mg²⁺ ions in the LiMn₂O₄ phase. LiMg_yMn_2−yO₄ (y=0 – 0.3) has been synthesized by a thermal method and characterized using XRD, TG/DTA and FTIR. The electrochemical performance is correlated with the dopant concentration.     

Convenient Method for the Synthesis of N-(Ethyloxycarbonyl) Ester Derivatives from Amino Acids

Amino acids upon treatment with ethyl chloroformate in methanol in the presence of potassium carbonate give the corresponding N-(ethyloxycarbonyl) amino acid ester derivatives in good yields. These derivatives can be also synthesized by performing the reaction in THF in the presence of alcohols.     

Reactive iron carbonyl reagents via reaction of metal alkoxides with Fe(CO)5 or Fe2(CO)9: synthesis of cyclobutenediones via double carbonylation of alkynes

Alkoxy bases such as t-BuOK react with Fe(CO)(5) to give reactive iron carbonyl intermediates that in turn react with alkynes at 70 °C in THF to give 1,2-cyclobutenediones in 70-93% yields after CuCl(2)·2H(2)O oxidation. A novel 1,2-diacyloxyferrole derivative was isolated in the reaction of diphenylacetylene with Fe(CO)(5)/t-BuOK in the presence of acetyl chloride in contrast to the formation of a 1,4-diacyloxyferrole complex formed in the reaction using Fe(CO)(5)/Me(3)NO. The Fe(2)(CO)(9)/t-BuOK reagent system also converts the alkynes to corresponding cyclobutenediones in 63-90% yields under similar reaction conditions.     

Influence of membrane lipid composition on the activity of functionally reconstituted LmrA under high hydrostatic pressure

In cellular membranes, proteins and lipids are in sensitive macromolecular interaction influencing each other. To evaluate this interaction, the multi-drug transporter LmrA from Lactococcus lactis was functionally reconstituted in vesicles consisting of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), DMPC+10 mol% cholesterol and the model raft mixture DOPC/1,2-dipalmitoyl-sn-glycero-3-phosphocholine/cholesterol (1:2:1) and in natural membrane lipids at 30 °C. The lateral structure and organization of these proteoliposomes were modulated using high hydrostatic pressure. A sharp pressure-induced fluid-to-gel phase transition is observed without an extended two-phase region. The possibility for lipid sorting, such as for DMPC/cholesterol bilayers, has an inhibitory effect on the LmrA activity. A fluid-like membrane phase over the whole pressure range with suitable hydrophobic matching, such as for DOPC, prevents the membrane protein from high-pressure inactivation up to 200 MPa. Under high-pressure conditions, highest LmrA activities, exceeding those at ambient pressure, are achieved for heterogeneous lipid matrices with a small hydrophobic mismatch and the ability of lipid sorting.     

Anisotropic transport of microalgae Chlorella vulgaris in microfluidic channel

In this work, we study the regional dependence of transport behavior of microalgae Chlorella vulgaris inside microfluidic channel on applied fluid flow rate. The microalgae are treated as spherical naturally buoyant particles. Deviation from the normal diffusion or Brownian transport is characterized based on the scaling behavior of the mean square displacement(MSD) of the particle trajectories by resolving the displacements in the streamwise(flow) and perpendicular directions.The channel is divided into three different flow regions, namely center region of the channel and two near-wall boundaries and the particle motions are analyzed at different flow rates. We use the scaled Brownian motion to model the transitional characteristics in the scaling behavior of the MSDs. We find that there exist anisotropic anomalous transports in all the three flow regions with mixed sub-diffusive, normal and super-diffusive behavior in both longitudinal and transverse directions.     

Solvent Exchange in Excited-State Relaxation in Mixed Solvents

The fluorescence of styrylthiazoloquinoxaline (STQ) in the solvent mixture methanol and dichloromethane (DCM) and 2-octanol have many common characteristics: biexponential fluorescence decay, wavelength-dependent amplitudes, a negative amplitude for the short-lifetime component at long emission wavelengths, and a time-dependent red shift of the emission spectrum. In octanol, the fluorescence lifetime decreases with increasing temperature, whereas the lifetime increases with temperature in the methanol/DCM mixture. The fluorescence characteristics in 2-octanol ( = 7.29 cP) are readily explained by the conventional model of excited-state relaxation kinetics by solvent reorientation. This model is not applicable for low-viscosity ( = 0.455 cP) solvent mixtures. A model of excited-state relaxation kinetics involving solvent exchange (versus solvent reorientation in pure solvents) in the excited state is proposed for the solvent mixture. The model assumes that the solvent compositions around the solute are different in the ground and excited states and the solvent composition is temperature dependent.     

Sensing of Pyrophosphate Anion by a Fluorescent Zn(II) Complex Bearing Acenaphthene Imidazole Moiety

Journal of Analytical Chemistry - Acenaphthene imidazole ligand (AIMP) reacted with zinc acetate for the synthesis of Zn-AIMP complex which was used to detect pyrophosphate (PPi) ions in the...     

Investigations on Na-ion conducting electrolyte based on sodium alginate biopolymer for all-solid-state sodium-ion batteries

Journal of Solid State Electrochemistry - Herein, solid biopolymer electrolyte membranes based on sodium alginate are prepared and investigated for their application in sodium-ion batteries....