Heterogeneous surface properties on wallstents

Wallstent has been successfully used to open up clogged peripheral arteries. Co? Cr alloy is the preferred metal for the construction of wallstent. Unfortunately, major complications such as in‐stent intimal hyperplasia,stent obstruction, and stent stricture are often reported, and these complications could be related to the metallic properties of the wallstent. In this study, the electrochemical properties of Co? Cr wires from wallstent were investigated using cyclic polarization, open‐circuit potential, potentiostatic condition, and electrochemical impedance spectroscopy. Scanning electron microscopy and X‐ray mapping were also employed to investigate the surface morphology and elemental distribution after electrochemical measurement. Results of this study showed the heterogeneous electrochemical properties of Co? Cr alloy wires that could result in severe galvanic corrosion of wallstent after implantation. Severe corrosion process could cause fracture of wallstent, resulting in localized inflammation, allergy, and thicker neointima. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis and Cytotoxicity Studies of Cyclohepta[b]indoles,Benzo[6,7]Cyclohepta[1,2‐b]Indoles,Indeno[1,2‐b]Indoles,and Benzo[a]Carbazoles

Synthesis and biological evaluation of various tricyclic and tetracyclic indoles are described. A number of these compounds possess in vitro activity against human nasopharyngeal carcinoma (HONE‐1) and gastric adenocarcinoma (NUGC‐3) cell lines.     

Characterization of protein adducts formed by toxic alkaloids by nano‐scale liquid chromatography with mass spectrometry

Betel quid chewing is associated with cytotoxicity, genotoxicity and carcinogenicity in diseases such as oral cancer, liver cirrhosis, hepatocellular carcinoma and diabetes mellitus. Arecoline and arecaidine, which are the main alkaloids in the areca nut, are potential exposure biomarkers in habitual betel quid users. This study developed a method of detecting arecoline‐ and arecaidine‐protein adducts by mass spectrometry (MS). First, bovine serum albumin was used to predict and confirm the binding sites of proteins modified by arecoline or arecaidine. Cells were then treated with arecoline to identify new protein adducts after cellular metabolic processing. Finally, human plasma was used to model long‐term exposure to arecoline and arecaidine. Following isolation proteins were tryspin digested. The peptides afforded were separated and analyzed by nano‐scale liquid chromatography with MS using an LTQ Orbitrap mass spectrometer. The experimental findings showed that cysteine is the predominant amino acid in protein adduct formation. The goal of this study was to establish a screening platform for identifying novel protein adducts that form covalent bonds with arecoline or arecaidine. Use of this strategy to survey new protein‐toxic adducts may help to identify novel biomarkers of betel nut exposure. Copyright © 2012 John Wiley & Sons, Ltd.     

Determination of common anions in oxalate by ion chromatography coupled with UV photolysis pretreatment

A new and simple method was developed to determine anions in oxalate of analytical reagent grade.After UV photolysis with optimal 1%H₂O₂ in 10,000 mg/L oxalate in the fabricated photoreactor,sample was directly injected into IC system.Satisfactory linearity,detections limits,good repeatability and spiked recovery were obtained.The method was successfully applied to determine anions in two commercial oxalate samples.     

The Protective Effect of Violaxanthin from Nannochloropsis oceanica against Ultraviolet B‐Induced Damage in Normal Human Dermal Fibroblasts

Skin photoaging, which is mainly induced by ultraviolet B (UVB) radiation, is prevented by the application of UV‐protective agents. The microalga Nannochloropsis oceanica (N. oceanica) has been primarily reported as a potential biofuel; however, in this study, we investigated whether N. oceanica extracts exerted photoprotective effects against UVB‐irradiated human dermal fibroblasts (HDFs) and which single component was responsible for the protective effect of the extracts. Two extracts—pigment and nonpigment—were prepared from N. oceanica biomass. WST‐1 assay and expression analysis of interleukin genes showed that the pigment extracts were not significantly cytotoxic to HDFs. Further experiments revealed that treatment with the pigment extract upregulated the expression of collagen genes and significantly blocked UVB‐induced damage such as decreased cell viability and increased ROS production. Next, to investigate the pigment composition of the extracts, HPLC analysis was conducted and violaxanthin was identified as the major pigment. The UVB photoprotective effect of the pigment extracts was confirmed in violaxanthin‐treated HDFs. In addition, violaxanthin significantly attenuated UVB‐induced G1 phase arrest, senescence‐associated β‐galactosidase activation, p16 and p21 upregulation, ERK phosphorylation and the downregulation of ECM molecules in HDFs. Therefore, we concluded that violaxanthin was a potential antiphotoaging agent.     

Synthesis of the Sex Attractant (7Z,11Z)-Hexadecadienal of the Citrus Leafminer Moth,Phyliocnietis Citrella Stainton

A component (7Z,11Z)-hexadecadienal of the sex attractant of the citrus leafminer moth was synthesized through a new (C₆ + C₃) + C₇ approach.     

Synthesis, crystal structure and properties of a charge-transfer compound [(CH3)3CNH3]3[PMo12O40] · 2H2O

A charge-transfer compound [(CH₃)₃CNH₃]₃[PMo₁₂O₄₀] · 2H₂O was synthesized and characterized by IR, UV, ESR, diffusion reflectance electronic spectrum, cyclic voltammogram and X-ray crystallography. Oxygen atoms of the polyoxometalate anion, N atoms of organic substrates (CH₃)₃CNH₂ and O atoms of water molecules are involved in hydrogen bonding. The solid reflectance electronic spectra and IR data indicate the presence of interaction between the [PMo₁₂O₄₀]³⁻ and the organic substrates in the solid state. Photosensitivity to ultraviolet light was assessed for the compound, showing that charge-transfer resulted from oxidation of the organic substrates and the reduction of the heteropolyanion.