Facile polystyrene/ZnO/Fe3O4 nanocomposites prepared via a hydrothermal approach for enhancement of MB dye degradation

Research on Chemical Intermediates - In this present work, polystyrene/ZnO and polystyrene/ZnO/Fe3O4 nanocomposites (NCs) were prepared by a hydrothermal synthesis method. The crystalline nature of...     

A new acylated isoflavone glucoside from Pterocarpus santalinus

Phytochemical investigation on the constituents of heartwood of Pterocarpus santalinus resulted in the isolation of a new acylated isoflavone glucoside. The structure of the new compound was elucidated on the basis of spectral studies as 4',5-dihydroxy-7-O-methyl isoflavone 3'-O-D-(3'-E-cinnamoyl)glucoside.     

β‐Cyclodextrin‐Supported,Completely Regioselective Ring Opening of Thiiranes with Thiophenol in Water

Thiolysis of thiiranes I with thiophenols II is performed efficiently in the presence of β‐cyclodextrin in water with high regioselectivity (Scheme, Table).     

Synthesis and characterization of highly transparent and hydrophobic fluorinated polyimides derived from perfluorodecylthio substituted diamine monomers

Two new perfluorodecylthio substituted aromatic diamines, namely 2,4‐diamino‐1‐(1H,1H,2H,2H‐perfluorodecathio)benzene (DAPFB) and 2,2'‐Bis((1H,1H,2H,2H‐perfluorodecyl)thio)[1,1'‐biphenyl]4,4'‐diamine (BPFBD) were synthesized and polycondensed with 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride (6FDA) to produce two new perfluorinated polyimides (PI2 and PI4). The chemical structures of these polyimides were confirmed by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy and elemental analysis. Two other polyimides (PI1 and PI3) were also synthesized from 6FDA and analogous perfluorodecylthio unsubstituted diamines to investigate the incorporation effect of perfluorodecylthio group on various physical and chemical properties of the synthesized PIs. Compared with PI1 and PI3, PI2 and PI4 exhibited improved solubility, optical transparency, and hydrophobicity, lower moisture absorption, dielectric constant, and thermo‐mechanical stabilities owing to the presence of the perfluorodecylthio side group in the polymer chain. Even though thermo‐mechanical properties of PI2 and PI4 ( : 413 and 404 °C, T_g: 220 and 209 °C, tensile strength of 101 and 76 MPa, tensile modulus of 1.7 and 1.5 GPa and elongation at break of 8 and 10%, respectively) were reduced in comparison to PI1 and PI3 but still were good enough for most of the practical applications. Most importantly, the presence of the perfluorodecylthio side group in BPFBD considerably reduced the dielectric constant of PI4 to 2.71 which was quite low as aromatic polyimide. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 479–488     

Properties of hydrophobically-modified graphene oxide (HG)/butyl rubber (IIR) nanocomposites prepared by shear mixing process

Abstract

Butyl rubber (IIR)/hydrophobically modified graphene oxide (GO) (HG) nanocomposites were prepared via shear-induced compounding. Hydrophilic GO was synthesized through the chemical oxidation of graphite (GP) and modified hydrophobically by octadecylamine which has a hydrophobic long alkyl chain. The obtained HG was characterized by Fourier transform infrared and wide-angle X-ray diffraction (WAXD) patterns. It was well dispersed in toluene for more than 30 days under stationary condition. The IIR/HG nanocomposites were prepared by the shear mixing process and followed by thermal vulcanization process through compression molding. Their properties were studied using oscillating disk rheometer, universal testing machine, differential scanning calorimetry, thermogravimetric analysis, WAXD patterns, and scanning electron microscope analysis. The hydrophobic HG was dispersed at the nanoscale within IIR matrix, and the resulting nanocomposites had significantly reduced curing time. The overall tensile properties were enhanced.     

Synthesis of beta-hydroxysulfides from alkenes under supramolecular catalysis in the presence of beta-cyclodextrin in water

An environmentally benign and highly efficient procedure has been developed for the direct one-pot synthesis of beta-hydroxysulfides in good yields under neutral conditions from alkenes and thiophenols in the presence of aerial oxygen using beta-cyclodextrin in water. This protocol tolerates a wide variety of functional groups or substrates and does not require the use of either acid or base catalysts. beta-Cyclodextrin can be recovered and reused for a number of runs without any loss of activity.     

Supramolecular catalysis of Strecker reaction in water under neutral conditions in the presence of beta-cyclodextrin

An environmentally benign and highly efficient procedure for the nucleophilic addition of trimethylsilyl cyanide to imines (Strecker reaction) has been developed under biomimetic conditions in water in the presence of beta-cyclodextrin to afford alpha-aminonitriles in quantitative yields. The use of cyclodextrin precludes the use of either acid or base, and the catalyst can be recycled a number of times without loss in activity.     

Proteomic analysis of differentially expressed proteins in vitamin C-treated AGS cells

Background

Vitamin C (ascorbic acid) is an essential nutrient of most living tissues that readily acts as a strong reducing agent, which is abundant in fruits and vegetables. Although, it inhibits cell growth in many human cancer cells in vitro, treatment in cancer is still controversial. Hence, the purpose of this study was to investigate the molecular mechanism of the inhibitory effect of vitamin C on AGS cell growth, and protein profiles in AGS cells after exposure to vitamin C treatment, by using proteomic tools.

Results

Vitamin C showed a cytotoxic effect on AGS cells (IC50 300 μg/mL) and, 20 differentially expressed proteins (spot intensities which show ≥2 fold change and statistically significant, p<0.05 between the control and vitamin-C treated group) were successfully identified by assisted laser desorption/ ionization-time of flight/mass spectrometry (MALDI-TOF/MS). Of the 20 proteins, six were up-regulated and fourteen were down-regulated. Specifically, 14-3-3σ, 14-3-3?, 14-3-3δ, tropomyosin alpha-3 chain and tropomyosin alpha-4 chain were down-regulated and peroxiredoxin-4 and thioredoxin domain-containing proteins 5 were up-regulated. The identified proteins are mainly involved in cell mobility, antioxidant and detoxification, signal transduction and protein metabolism. Further, the expressions of 14-3-3 isoforms were verified with immuno-blotting analysis.

Conclusions

Our proteome results suggest that the apoptosis related proteins were involved in promoting and regulating cell death of AGS cells, and might be helpful to understand the molecular mechanism of vitamin C on AGS cell growth inhibition.