Altered Lipid Composition of Secretory Cells Following Exposure to Zinc Can Be Correlated to Changes in Exocytosis

A micromolar concentration of zinc has been shown to significantly change the dynamics of exocytosis as well as the vesicle contents in a model cell line, providing direct evidence that zinc regulates neurotransmitter release. To provide insight into how zinc modulates these exocytotic processes, neurotransmitter release and vesicle content were compared with single cell amperometry and intracellular impact vesicle cytometry with a range of zinc concentrations. Additionally, time-of-flight secondary ion mass spectrometry (ToF-SIMS) images of lipid distributions in the cell membrane after zinc treatment correlate to changes in exocytosis. By combining electrochemical techniques and mass spectrometry imaging, we proposed a mechanism by which zinc changes the fusion pore and the rate of neurotransmitter release by changing lipid distributions and results in the modulation of synaptic strength and plasticity.     

One-pot,solvent-free and efficient synthesis of 2,4,6-triarylpyridines catalyzed by nano-titania-supported sulfonic acid as a novel heterogeneous nanocatalyst

Nano titania-supported sulfonic acid (n-TSA) has found to be a highly efficient, eco-friendly and recyclable heterogeneous nanocatalyst for the solvent-free synthesis of 2, 4, 6-triarylpyridines through one-pot three-component reaction of acetophenones, aryl aldehydes and ammonium acetate. This reported method illustrates several advantages such as environmental friendliness reaction conditions, simplicity, short reaction time, easy work up, reusability of catalyst and high yields of the products. One new compound is reported too. Furthermore, the catalyst could be recycled after a simple work-up, and reused at least six times without substantial reduction in its catalytic activity.     

Bilayer Cylindrical Conduit Consisting of Electrospun Polycaprolactone Nanofibers and DSC Cross‐Linked Sodium Alginate Hydrogel to Bridge Peripheral Nerve Gaps

Herein, a bilayer cylindrical conduit (P‐CA) is presented consisting of electrospun polycaprolactone (PCL) nanofibers and sodium alginate hydrogel covalently cross‐linked with N,N′‐disuccinimidyl carbonate (DSC). The bilayer P‐CA conduit is developed by combining the electrospinning and outer–inner layer methods. Using DSC, as a covalent crosslinker, increases the degradation time of the sodium alginate hydrogel up to 2 months. The swelling ratio of the hydrogel is also 503% during the first 8 h. The DSC cross‐linked sodium alginate in the inner layer of the conduit promotes the adhesion and proliferation of nerve cells, while the electrospun PCL nanofibers in the outer layer provide maximum tensile strength of the conduit during surgery. P‐CA conduit promotes the migration of Schwann cells along the axon in a rat model based on functional and histological evidences. In conclusion, P‐CA conduit will be a promising construct for repairing sciatic nerves in a rat model.     

MWCNTs@NHBut/PTA: New efficient solid acid catalyst for solvent free synthesis of benzochromenopyrimidines

In this study, a novel and eco‐friendly synthesis of benzochromenopyrimidines catalyzed by phosphotugstic acid immobilized on aminated multiwalled carbon nanotubes (MWCNTs@NHBut/PTA) is reported. New solid acid catalyst was prepared through a simple process with good percentage of organo metallic groups and characterized with FTIR, TEM, SEM, EDX and TGA techniques. Reusable catalytic system provides a convenient, safe and green pathway to generate a variety of benzochromenopyrimidines under mild conditions.     

Two-phase simulation of nanofluid flow in a heat exchanger with grooved wall

Journal of Thermal Analysis and Calorimetry - The aim of this paper is to achieve a smaller and cheaper heat exchanger with similar performance. To fulfill this demand, ANSYS-Fluent software and...     

Deferiprone solubility in some non-aqueous mono-solvents at different temperatures: experimental data and thermodynamic modelling

The solubility of deferiprone (DFP) in five organic solvents including ethyl acetate, chloroform, acetonitrile, 1,4-dioxane and dichloromethane was investigated by the flask-shake method under atmospheric pressure at temperatures ranging from 293.15 to 313.15 K. In general, the solubility (mol L^–1) obeyed the following order from high to low in different mono-solvents: dichloromethane > chloroform > acetonitrile > 1,4-dioxane > ethyl acetate. The solubility of DFP in the mono-solvents increased with a rise of temperature. The solubility data were successfully correlated with the van’t Hoff equation. The generated data in this work and the previously published data were used to calculate the thermodynamic parameters of the system using the modified van’t Hoff equation, and the derived thermodynamic properties were correlated using Abraham solvation parameters.     

Voltammetric Determination of Methimazole Using a Carbon Paste Electrode Modified with a Schiff Base Complex of Cobalt

The electrochemical behavior of methimazole, as an antithyroid agent, is investigated on the surface of a carbon‐paste electrode modified with a newly synthesized Schiff base complex of cobalt. The prepared modified electrode showed an efficient catalytic role in the electrochemical oxidation of methimazole, leading to remarkable decrease in oxidation overpotential and enhancement of the kinetics of the electrode reaction. The mechanism of the electrocatalytic process on the surface of the modified electrode is analyzed by obtaining the cyclic voltammograms in various potential sweep rates and pHs of the buffer solutions. The differential pulse voltammetry is applied as a very sensitive analytical method for the determination of sub‐micromolar amounts of methimazole. A linear dynamic range of 1×10^?6 to 1×10^?4 M with a detection limit of 5×10^?7 M is resulted for methimazole. The modified electrode is successfully applied for the accurate determination of methimazole in pharmaceutical and clinical preparations. The linear range in calibration curves remains constant in addition to tablet preparations of methimazole and also in spiking to the synthetic human serum samples. In comparison to calibration curves in background buffer solution, the slope of the curves showed a variation less than 3% in determinations in background solutions of tablet and human synthetic serum samples. These results showed high efficiency of the Voltammetric procedure for accurate determination of methimazole in drug and clinical preparations. The modified electrode can be prepared very easy and renewed in its surface by simple polishing. The reproducibility of the electrode response, based on ten measurements during two month, was 3.2% for the slope of the calibration curve.     

Highly Efficient, Four Component, One-pot Synthesis of Tetrasubstituted Imidazoles Using a Catalytic Amount of FeCl3 · 6H2O

An efficient and improved procedure for the synthesis of tetrasubstituted imidazoles by FeCl₃ · 6H₂O catalyzed four-component one-pot synthesis in refluxing ethanol is described.     

修饰的多壁碳纳米管糊电极用于生物与制药样品中苄丙酮香豆素电催化氧化和测定

采用一种简单灵敏的方法开发了在多壁碳纳米管修饰的ZnCrFeO4糊电极(MWCNTs/ZnCrFeO4/CPE)表面测定苄丙酮香豆素的新型传感器.运用循环伏安法、差示脉冲伏安法、计时电流法和电化学阻抗谱考察了该化学修饰电极上苄丙酮香豆素的电化学性能.结果表明,MWCNTs/ZnCrFeO4/CPE电极对苄丙酮香豆素氧化表现出较高的电催化活性,在pH=4时,产生峰值氧化电流约0.97 vs Ag/AgCl参比电极.当苄丙酮香豆素浓度在0.02-920.0 μmol/L范围内,该峰电流与其呈线性关系,检测极限(3σ)为0.003 μmol/L.另外,运用差示脉冲伏安法测定了MWCNTs/ZnCrFeO/CPE电极上苄丙酮香豆素的催化反应速率常数和扩散系数.