Hard templating of nanocrystalline titanium dioxide with chiral nematic ordering

Anatase TiO(2) nanocrystals have been organized into high-surface-area (150-230 m(2) g(-1)) mesoporous films with long-range chiral nematic ordering. The chiral structure of the anatase films causes them to selectively reflect circularly polarized light and appear iridescent. These materials show replication of structural features found in the silica template on nanometer to millimeter length scales.     

Quick bioanalytical method of quantification and validation of sulbactam in plasma using high performance liquid chromatography

A quick method of quantitative determination of sulbactam in human plasma, using liquid chromatography-UV spectroscopy, has been developed and validated. After derivatization with imidazole, plasma samples were treated by direct deproteinization with acetonitrile as an extraction solvent. After ultracentrifugation, sulbactam extract was directly injected onto the LC column. Chromatographic separation was performed on TSK Gel Super ODS (50 mm × 4.6 mm i.d., 2 μm) using methanol and phosphate buffer with tetrabutylammonium hydroxide solution as a mobile phase. Gradient elution was employed. The method was fully validated according to the United States Food and Drug Administration requirements (linearity, precision, trueness, quantification limit, detection limit, recovery, specificity and stability). The calibration curves were linear within the concentration range of 0.05–4.0 μg mL⁻¹. Good method/system precision and accuracy of the method were demonstrated.      

Effect of elevated concentrations of strontium and iron on the structural and dielectric characteristics of Ba(1−x−y)Sr(x)Ti Fe(y)O3 prepared through sol–gel technique

Nano-composite Ba_1−xSr_(x)TiO₃ (BST), where x=0.01–0.50 and doped with different concentrations of iron Ba_(1−x−y)Sr_(x)TiFe _(y)O₃ (BSTF), where x=0.01 and y=0.01–0.05 powders were prepared by sol–gel method.     

Conversion of 2(3H)‐furanones bearing indole nuclei into novel amide,pyrrolone, and imidazole derivatives

2(3H)‐Furanones 1a–d having exocyclic double bond and N‐acetylisatin nucleus were converted into the corresponding novel amides, pyrrolones, and imidazoles via nitrogen nucleophiles. All purposed structures were confirmed by NMR, mass spectra GC/MS, and chemical evidence. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:434–442, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10175     

Silk Meshes Coated with Chitosan-Bioactive Phytochemicals Activate Wound Healing Genes In Vitro

Meshes from natural silk are hand knitted and surface functionalized to facilitate hernia repair and other load bearing, tissue applications. Purified organic silk is - hand knitted and then coated with chitosan (CH)/bacterial cellulose (BC) blend polymer using four phytochemicals such as pomegranate (PG) peel, Nigella sativa (NS) seed, Licorice root (LE), and Bearberry leaf extracts (BE) separately. Characterizations using GCMS analysis shows the presence of bioactive chemicals in the extracts. Scanning electron microcopy (SEM) shows that the surface is coated with the composite polymer t. Fourier transform infrared spectroscopy (FTIR) shows significant elements found in CH, BC, and phytochemicals in plant extracts with no chemical changes. Tensile strength of the coated meshes is higher to support tissue as implants. The release kinetics suggest sustained release of phytochemical extracts. In vitro studies confirmed the noncytotoxic, biocompatible, wound healing potential of the meshes. Furthermore, gene expression analysis of 3-wound healing genes shows marked increase in the in vitro cell cultures due to the presence of extracts. These results suggest that the composite meshes can efficiently support hernia closure while facilitating wound/tissue healing and combating bacterial infections. Therefore, these meshes can be good candidates for fistula and cleft palate repair.     

Reactivity of pyridazin‐3(2H) thiones

4,6‐Disubstituted pyridazin‐3(2H) thiones 3a–f were prepared by thiation of 4,6‐disubstituted pyridazin‐3(2H)‐one 1a–f either with thiourea or phosphorus pentasulphide. The reactivity of 3a‐f towards nucleophilic and electrophilic species under different conditions was studied successively. The structure of the products was confirmed by NMR and mass spectral data. Mechanisms for their formation are also proposed. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:334–341, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10157