Effect of berberine on the viability of adipose tissue-derived mesenchymal stem cells in nutrients deficient condition

This study was designed to examine whether berberine protects rat adipose tissue-derived stem cells (ASCs) against glucose and serum deprivation (GSD)-induced cell death. ASCs were cultured for 24 h in GSD condition in the presence of berberine and then cell viability, apoptosis and generation of reactive oxygen species (ROS) were evaluated. The GSD condition significantly decreased ASCs viability and increased ROS generation and apoptosis. Incubation with 0.75–3 μM berberine partially increased cell viability and decreased ROS generation and apoptosis in GSD condition. In conclusion, berberine partially protects ASCs in nutrients deficient condition and may help ASCs to preserve their survival during cell therapy of ischemia.     

Ultrasound‐assisted magnetic dispersive solid‐phase microextraction: A novel approach for the rapid and efficient microextraction of naproxen and ibuprofen employing experimental design with high‐performance liquid chromatography

A simple, rapid, and sensitive method for the determination of naproxen and ibuprofen in complex biological and water matrices (cow milk, human urine, river, and well water samples) has been developed using ultrasound‐assisted magnetic dispersive solid‐phase microextraction. Magnetic ethylendiamine‐functionalized graphene oxide nanocomposite was synthesized and used as a novel adsorbent for the microextraction process and showed great adsorptive ability toward these analytes. Different parameters affecting the microextraction were optimized with the aid of the experimental design approach. A Plackett–Burman screening design was used to study the main variables affecting the microextraction process, and the Box–Behnken optimization design was used to optimize the previously selected variables for extraction of naproxen and ibuprofen. The optimized technique provides good repeatability (relative standard deviations of the intraday precision 3.1 and 3.3, interday precision of 5.6 and 6.1%), linearity (0.1–500 and 0.3–650 ng/mL), low limits of detection (0.03 and 0.1 ng/mL), and a high enrichment factor (168 and 146) for naproxen and ibuprofen, respectively. The proposed method can be successfully applied in routine analysis for determination of naproxen and ibuprofen in cow milk, human urine, and real water samples.     

Ultrahigh‐Resolution Diffusion‐Ordered Spectroscopy

Diffusion‐ordered spectroscopy (DOSY) is an effective method for the analysis of intact mixtures, but the quality of results is critically limited by resolution in the NMR dimension. A new experiment integrating diffusion weighting into the PSYCHE method for pure shift NMR spectroscopy allows DOSY spectra to be measured with ultrahigh NMR resolution at improved sensitivity.     

Microstructure and Properties of Polypropylene/Clay Nanocomposites

Nanocomposites of polypropylene (PP) containing various contents of Cloisite 15A nanoclay particles were prepared by one-step melt compounding in a twin screw extruder. Tensile and impact properties of the nanocomposite systems were investigated and correlated with their microstructures. The tensile modulus increased with an increase in Cloisite 15A content but the tensile strength, elongation at break, and impact strength were decreased. WAXS and TEM studies showed almost exfoliated structures. There was a decrease in permeability values with an increase in nanoclay content up to 5 wt. %. Exceeding this content of nanoclay had no significant effect on permeation due to the aggregation phenomenon at high concentrations of the nanoparticles. Most of the examined micromechanical models for prediction of the tensile modulus of the nanocomposite were successful despite being based on fiber-shaped fillers. An exfoliated structure of clay within the nanocomposite was assumed for the modeling using a molecular dynamics simulations approach, employing Dreiding, Forcite, and COMPASS force fields, in order to investigate the best one for a successful estimation of elastic modulus. Relative to the experimental modulus values of the nanocomposites, which were around 1100–1200 MPa, the COMPASS force field had the best correlation with the values with a slight departure of about 10%.     

Optimization of dispersive liquid-liquid microextraction of copper (II) by atomic absorption spectrometry as its oxinate chelate: application to determination of copper in different water samples

In this study a dispersive liquid-liquid microextraction (DLLME) method based on the dispersion of an extraction solvent into aqueous phase in the presence of a dispersive solvent was investigated for the preconcentration of Cu(2+) ions. 8-Hydroxy quinoline was used as a chelating agent prior to extraction. Flame atomic absorption spectrometry using an acetylene-air flame was used for quantitation of the analyte after preconcentration. The effect of various experimental parameters on the extraction was investigated using two optimization methods, one variable at a time and central composite design. The experimental design was performed at five levels of the operating parameters. Nearly the same results for optimization were obtained using both methods: sample size 5 mL; volume of dispersive solvent 1.5 mL; dispersive solvent methanol; extracting solvent chloroform; extracting solvent volume 250 microL; 8-hydroxy quinoline concentration and salt amount do not affect significantly the extraction. Under the optimum conditions the calibration graph was linear over the range 50-2000 muicro L(-1). The relative standard deviation was 5.1% for six repeated determinations at a concentration of 500 microg L(-1). The limit of detection (S/N=3) was 3 microg L(-1).     

N,N,N′,N′‐Tetrabromobenzene‐1,3‐Disulfonamide and Poly(N‐Bromo‐N‐Ethyl‐Benzene‐1,3‐Disulfonamide) as Efficient Catalysts for the Methoxymethylation of Alcohols under Solvent‐Free Conditions

Methoxymethylation of a variety of alcohols was performed using formaldehyde dimethyl acetal in the presence of N,N,N′,N′‐tetrabromobenzene‐1,3‐disulfonamide [TBBDA] and poly(N‐bromo‐N‐ethylbenzene‐1,3‐disulfonamide) [PBBS] as catalysts at room temperature and solvent‐free conditions. The methoxymethyl ethers (MOM‐ethers) were obtained with good to excellent yields.     

Polystyrene-Bound Hydrazone Schiff Base Molybdenum Complex: Synthesis,Characterization, and Application as a Reusable Heterogeneous Catalyst in the Oxidation of Sulfides

Russian Journal of Organic Chemistry - A dioxomolybdenum hydrazone Schiff base complex immobilized on chloromethylated polystyrene [MoO2L@CMP] was synthesized and characterized by various...     

Silica Chloride/NaNO2 as a Novel Heterogeneous System for the Nitration of Phenols Under Mild Conditions

Nitrophenols can be obtained via direct nitration of phenols with silica chloride, NaNO₂, and wet SiO₂ at room temperature in moderate to high yields.

     

An Efficient Catalytic Procedure for the Selective Oxidation of Sulfides to Sulfoxides by Citric Acid/Al(NO3)3.9H2O/MBr Under Mild and Heterogeneous Conditions

A wide range of aliphatic or aromatic sulfides are selectively oxidized to the corresponding sulfoxides using Al(NO₃)₃.9H₂O, citric acid and a catalytic amount of KBr or NaBr in the presence of wet SiO₂ (50% w/w)in CH₂Cl₂ under mild and heterogeneous conditions in good to high yields.