Clean preparation of S-thiocarbamates with in situ generated hydroxide in 2-methyltetrahydrofuran

A simple and clean protocol for the synthesis of various alkyl and (hetero)aryl S-thiocarbamates was established. The usage of in situ generated hydroxide as both an oxygen source and hydrogen source as well as biomass-derived 2-methyltetrahydrofuran as a green reaction medium, the avoidance of phosphorus-containing reductant, and the generation of harmless water and nitrogen as the side-products have given the present method atom-economy and environmental friendliness.     

A STUDY ON THE RECEPTIVE FIELD OF ACUPOINTS AND THE RELATIONSHIP BETWEEN CHARACTERISTICS OF NEEDLING SENSATION AND GROUPS OF AFFERENT FIBRES

We have recorded the afferent unit discharges and using it as an index, measured the locations and the volumes of nine acupoints, such as Neiguan and Shaoshang, which are innervated by median nerve. We have also investigated. the relationships between electric needling sensations and afferent fibres of different groups as well as manual needling sensations by means of analysing power-spectrum of the unit discharges with FFT. It has been found that the fibres of Group Ⅱ and Group Ⅳ convey numbness and soreness, respectively. The fibres of Group Ⅲ relates to the conduction of heaviness and distention closely.     

THEORETICAL AND COMPUTATIONAL INVESTIGATIONS OF NONLINEAR WAVE PROPAGATIONS IN ARTERIES (Ⅰ)——A THEORETICAL MODEL OF NONLINEAR PULSE WAVE PROPAGATIONS

In this paper, a new theoretical model of nonlinear wave propagations in arteries with surrounding tissues was put forward. The equations of motion for the blood vessels and their peripheral tissues as a system have been derived. These equations were expressed in terms of the stresses of the vessel wall and fluid, and the geometry of the blood vessel. They can be used to solve numerically the problems for the propagations of nonlinear pulse waves in arteries together with the momentum and continuity equations of incompressible-viscous flow, as well as the constitutive equations of fluid and vessel wall. The numerical solutions can involve pressure, velocities and flowrate of the blood flow, as well as displacements, velocities and stresses of the vessel wall. These physical variables of propagations of pulse waves in arteries are all of significance physiologically and clinically.     

Conversion of Methane to C2 Hydrocarbons via Cold Plasma Reaction

Direct conversion of methane to C2 hydrocarbons via cold plasma reaction with catalysts has been studied at room temperature and atmospheric pressure. Methane can be converted into C2 hydrocarbons in different selectivity depending on the form of the reactor, power of plasma, flow rate of methane, ratio of N2/CH4 and nature of the catalysts. The selectivity to C2 hydrocarbons can reach as high as 98.64%, and the conversion of methane as high as 60% and the yield of C2 hydrocarbons as high as 50% are obtained. Coking can be minimized under the conditions of: proper selection of the catalysts, appropriate high flow rate of inlet methane and suitable ratio of N2 to CH4. The catalyst surface provides active sites for radical recombination.     

Antitumour Activity of Chitosan Hydrogen Selenites

Selenium is a biologically important element and essential for life1. Selenium deficiency causes severe degenerative disease, such as Kesan cardiomyopathy, and has been implicated in increasing the incidence of human cancer and some chronic ailment as well as ageing. Administration of selenium compounds such as sodium selenite protects animals against carcinogens and markedly reduces the incidence of various neoplasms in human2. Chitosan is one of the most abundant glycans in nature and its…     

Interfacial Degradation and Optimization of Li-rich Cathode Materials

High-energy and safe lithium ion batteries(LIBs)are in increasing need as the rapid development of electronic devices,electric vehicles,as well as energy storage station.Li-rich oxides have attracted a lot of attention due to their high capacity and low cost as cathode material for LIBs.However,they still suffer from the vulnerable cathode/electrolyte interface,which presents the huge challenges of surface degradation and gas release,particularly at high state of charge.Some issues of Li-rich cathode materials,such as moderate cycle stability and voltage decay,are in tight connection with electrode-electrolyte interfacial side reactions.Research in the area of interfacial degradation mechanism and optimization strategies is of great significance as for Li-rich cathode,and extensive efforts have been poured.This review aims to understand the degradation mechanism of Li-rich cathode materials,and summarize the corresponding valuable and effective optimization strategies.Based on these considerations,we also have discussed the remaining challenges and the future research direction.     

Catalysis Conversion Methane into C2 Hydrocarbons via Electric Field Enhanced Plasma

In this paper the effect of catalyst and carrier in electric field enhanced plasma on methane conversion into C2 hydrocarbons was investigated. Methane coupling reaction was studied in the system of continuous flow reactor on Ni, MoO3, MnO2 catalysts and different ZSM-5 carriers. The per pass conversion of methane can be as high as 22%, the selectivity of ethylene can be as high as 23.8%, of acetylene 60.8%, of ethane 5.4% and of total C2 hydrocarbons was more than 90%. ZSM-5-25 was the better carrier and MnO2 was the better active component. The efficiency of energy was as high as 7.81%.     

Direct Synthesis of Oxygenates from Water and Methane via Dielectric-barrier Discharge

In this investigation, a clean, atomic economic and direct synthesis of oxygenates (methanol, ethanol) form water and methane via dielectric-barrier discharge was developed at room temperature and under atmospheric pressure. The effect of discharge voltage on this process was studied. The results showed that the conversion of water can be as high as 7%, the selectivity of methanol and ethanol can be as high as 100%.     

Some problems in adsorption and calorimetric studies of the steps of catalytic processes

Principal side factors as well as technical and procedural peculiarities capable of distorting the results of measurements of adsorbed and desorbed amounts, of falsifying the nature of the processes proceeding in the systems under study, and of promoting artifacts in calorimetric and other studies of gas chemisorption on powders are considered. Modified techniques and procedures allowing the elimination of sources of side phenomena and artifacts and freeing traditional glass static adsorption apparatuses and experimental procedures from undesirable factors and peculiarities are proposed. Some available chemisorption and calorimetric data representing artifacts and also some data that are not artifacts but,due to imperfections of chemisorption techniques, show up as artifacts are presented and discussed. Several applications of the improved techniques and procedures to calorimetric and adsorption studies of the steps of catalytic processes proceeding on the basis of natural gas and of products of its processing are presented and discussed.     

Determination of Trace Amounts of Vanadium by Kinetic-Catalytic Spectrophotometric Methods

Kinetic-catalytic spectrophotometric methods were proposed for the determination of trace amounts of vanadium element as vanadium（Ⅳ） and/or V（Ⅴ） ions. The vanadium（Ⅳ） as VO^2＋ ion and/or vanadium（Ⅴ） as VO3^- ion showed a catalytic effect on the kinetic reactions between a color reagent such as methylthymol blue （MTB） or SPADNS and bromate in acidic media. The rate of decrease in the absorbance of the reagent MTB at 440 nm or SPADNS at 510 nm was proportional to concentration of V（Ⅳ） and/or V（Ⅴ） ions in the solution. The linear ranges for determination of vanadium were obtained in the range of 1.0-150 and 5.0-100.0 μg/L by the fixed-time and slope methods, respectively, with using MTB as reagent. In the presence of SPADNS as reagent, the calibration curves were made in the amplitude 1.0-200.0 and 5.0-150 μg/L of vanadium ion by the fixed-time and slope methods, respectively. Using fixed-time method, the limits of detection were obtained to be 0.5 and 0.7 μg/L of vanadium in the presence of MTB and SPADNS as reagents, respectively. Detection limits of vanadium by slope method and reagents of SPADNS and MTB were obtained to be 3.5 and 3.8 μg/L of vanadium, respectively. The proposed methods were applied successfully to determination of vanadium in synthetic and real samples.     

Some problerns in adsorption and calorimetric studies of the steps of catalytic processes

Principal side factors as well as technical and procedural peculiarities capable of distorting the results of measurements of adsorbed and desorbed amounts, of falsifying the nature of the processes proceeding in the systems under study, and of promoting artifacts in calorimetric and other studies of gas chemisorption on powders are considered. Modified techniques and procedures allowing the elimination of sources of side phenomena and artifacts and freeing traditional glass static adsorption apparatuses and experimental procedures from undesirable factors and peculiarities are proposed. Some available chemisorption and calorimetric data representing artifacts and also some data that are not artifacts but, due to imperfections of chemisorption techniques, show up as artifacts are presented and discussed. Several applications of the improved techniques and procedures to calorimetric and adsorption studies of the steps of catalytic processes proceeding on the basis of natural gas and of products of its pr     

Architecture of Platonic and Archimedean polyhedral links

A new methodology for understanding the construction of polyhedral links has been developed on the basis of the Platonic and Archimedean solids by using our method of the ‘three-cross-curve and dou- ble-twist-line covering’. There are five classes of polyhedral links that can be explored: the tetrahedral and truncated tetrahedral links; the hexahedral and truncated hexahedral links; the dodecahedral and truncated dodecahedral links; the truncated octahedral and icosahedral links. Our results show that the tetrahedral and truncated tetrahedral links have T symmetry; the hexahedral and truncated hexahedral links, as well as the truncated octahedral links, O symmetry; the dodecahedral and truncated dodeca- hedral links, as well as the truncated icosahedral links, I symmetry, respectively. This study provides further insight into the molecular design, as well as theoretical characterization, of the DNA and protein catenanes.     

Transformation of Oximes and Alcohols to Carbonyl Compounds Using Amberlite IRA-400 Supported Chromic Acid in the Presence of Zirconium Tetrachloride

A wide variety of oximes and alcohols were efficiently converted to their corresponding aldehydes and ketones in good to excellent yields using amberlite IRA-400 supported chromic acid in the presence of zirconium tetrachloride in refluxing acetonitrile-H2O. Selective oxidation of oximes and alcohols in the presence of other functional groups such as acetal, hydrazone, aldehyde, ether and alkene can be considered as a noteworthy advantage of this method. A wide variety of oximes and alcohols were efficiently converted to their corresponding aldehydes and ketones in good to excellent yields using amberlite IRA-400 supported chromic acid in the presence of zirconium tetrachloride in refluxing acetonitrile-H2O. Selective oxidation of oximes and alcohols in the presence of other functional groups such as acetal, hydrazone, aldehyde, ether and alkene can be considered as a noteworthy advantage of this method.     

CHEMOTHERAPEUTIC POLYMERS. THE SYNTHESIS OF POLYMERS CONTAINING 5-FLUOROURACIL IN THE MAIN CHAIN

1,3-Dialkyl-5-fluorouracil compounds and polymers containing 5-fluorouracil in the main chain were synthesized by the reaction of 5-fluorouracil with alkylbromidcs and polymethylene bromides respectively. The structures of the new compounds and polymers were confirmed by IR and NMR spectra as well as elemental analyses.The factors affecting the polycondensation, such as the temperature and time of the reaction were investigated. The anti-tumor activity of some of the 5-fluorouracil containing compounds and polymers were also measured.     

ELECTROCHEMISTRYOF RARE EARTH POLYACETYLENE

The electrochemical doping of rare earth polyacetylene (PA) employing aqueous electrolyte and the electrical potentials of the rare earth polyacetylene were studied. The half-plastic batteries consisting of doped polyacetylene as cathode and magnesium as anode aS well as aqueous solution as electrolyte were fabricated. Also, the electrical characteristics of the rechargeable battery with doped PA cathode and lithium anode in organic electrolyte were investigated.     

The lipase monolayer film self-assembly on the negatively charged poly(ethylene terephthalate) substrate

The artificial assembly of enzymes is of considerable interest in basic research fordevelopment of enzyme engineering as well as for technological applications.Since 1991, the molecular deposition developed by Decher and others has been aversatile method for the protein and enZyme molecules self.assembly as a noveltechnique of immobilized enZyme. The glucose isomerase and the bienZymes of glucoseoxidase and glucoamylase were assembled using molecular deposition on the surface ofthe canonized …     

Glucuronidation of Two Novel Metabolites of Benproperine with Trichloroacetimidate Donor

IntroductionGlucuronides are well known as phaseⅡ metabo-lites of xenobiotics, usually of phenols, alcohols, andacids, as well as those of hydroxylamines and tertiaryamine[1]. There is a growing interest in identifyingsuch metabolites and in establishing…     

Mechanism of cleaving DNA through hydrolysis of a novel complex of Mg containing dien ligand

A series of elements necessary for life bodies, such as Mg, Cu, Mn, Fe, Co, Zn etc, arechosen as ceflter ions of complexes, because most of them act as active centers ofenZymes and auxiliary factors. We select dien as ligand because nitrogen, especiallymuti-nitrogen coordination is general in natural enzymes and simulated systems,furthermore dien has structural flexibility.The complexes of Mg containing dien and the activity of cleaving DNAA series of metals, such as Mg, Mn, Fe, Co, Ni, …     

Biomimetic asymmetric catalysis

Enzymes are the core for biological transformations in nature. Their structures and functions have drawn enormous attention from biologists as well as chemists since last century. The large demand of bioactive molecules and the pursuit of efficiency and greenness of synthesis have spurred the rapid development of biomimetic chemistry in the past several decades. Biomimetic asymmetric catalysis, mimicking the structures and functions of enzymes, has been recognized as one of the most promising sy...     

Molecular Simulation on Transport Properties of Confined Water

The diffusivity and viscosity of water confined in micropores were studied by molecular dynamics simulations. The effects of pore width and density were analyzed at pore widths from 0.9 to 2.6nm. The diffusivity in micropores is lower than that of the bulk, and it decreases as pore width decreases and as density increases. But the viscosity in micropores is much larger than that of the bulk, and it increases as pore width decreases and as density increases. The diffusivity in channel parallel direction is obviously larger than that in channel perpendicular directions.