Thorium(IV) and uranium(VI) sorption studies on octacarboxymethyl-C-methylcalix[4]resorcinarene impregnated on a polymeric support

The impregnation of octacarboxymethyl-C-methylcalix[4]resorcinarene into a polymeric matrix, Amberlite XAD-4, is reported and was characterized by infrared spectroscopy. The sorption capacity of the impregnated resin is 0.34 x 10(-3) mol g(-1). The resin was used for the sorption of thorium(IV) and uranium(VI) from aqueous solution. The properties of capacity, pH effect, and breakthrough curves of the impregnated resin were investigated. The capacity of the resin for Th(IV) and U(VI) was found to be 0.29 and 0.27 x 10(-3) mol g(-1), respectively. The metal ions were eluted with 0.4-2 M HCl or HNO3. Chromatographic separation of Th(W) and U(VI) was accomplished by adjustment of pH to 3.0 and 6.0, respectively. The impregnated resin exhibits a high chemical stability, reusability and fast equilibration. Separation of Th(W) and U(VI) from other metal cations in synthetic solution was achieved. (C) 2003 Elsevier Science B.V. All rights reserved

Chiral separation of amino acids by chiral octamide derivatives of calixarenes derived from resorcinol by impregnation on a polymeric support

Chiral amide derivatives of octaester calixresorcarene were synthesized and employed as chiral stationary phases for chiral discrimination of amino acid derivatives. Enantiomers of phenylglycine and tryptophan were easily discriminated as their sodium and potassium salts. In addition, phenylalanine-trytophan, phenylglycine-trytophan mixtures were separated by column chromatography. (c) 2005 Elsevier Ltd. All rights reserved

evaluation of antioxidant, anticancer, and anti-MRSA activity

A rhizosphere isolate Streptomyces sp. CAH29 was found to possess potent antibacterial and antifungal activity against a variety of test organisms. Based on 16S ribosomal ribonucleic acid sequence homology studies, this strain was found to be similar to Streptomyces stramineus (gene sequence similarity 99 %). The major bioactive metabolite produced by Streptomyces sp. CAH29 isolate was extracted, purified andidentified by nuclear magnetic resonance as tetrangomycin. This known anthraquinone-exhibited antimicrobial activity against Staphylococcus aureus, Streptococcus pyogenes, methicillin resistant Staphylococcus aureus and Candida albicans with inhibition zones of 14, 10, 12 and 8 mm, respectively. Docking results demonstrate that tetrangomycin has a similar mode of action and a comparable docking score to bind to the dehydrosqualene synthase (CrtM) enzyme of methicillin resistant Staphylococcus aureus compared to the current inhibitor. Hence, this suggests that tetrangomycin has a potential to be used as an anti-methicillin resistant Staphylococcus aureus agent. Tetrangomycin also showed moderate free radical scavenging activity with 1,1-diphenyl-2-picryl-hydrazil. Tetrangomycin apparently decreased all of the studied cytokine (pro-inflammatory: interleukin 1B, interleukin 2, tumor necrosis factor and interleukin L6 and anti-inflammatory: interleukin 10) expression levels at IC50 concentrations in A459 (adenocarcinomic human alveolar basal epithelial) and LNCAP (human prostate adenocarcinoma) cell lines. In addition, it reduced Caspase 8 and 3 mRNA levels in LNCAP and A549 cells. This study describes for the first time novel in vitro immunosuppressive function of tetrangomycin by reducing the transcription of cytokine genes

E2 and S(N)2 reactions of X- + CH3CH2X (X = F, Cl); an ab initio and DFT benchmark study

We have computed consistent benchmark potential energy surfaces (PESs) for the anti-E2, syn-E2, and