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Work Reports (work + report)
Selected AbstractsClick Chemistry Inspired Synthesis of Novel Ferrocenyl-Substituted Amino Acids or PeptidesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 13 2009V. Sai Sudhir Abstract This work reports on the synthesis of a wide range of ferrocenyl-substituted amino acids and peptides in excellent yield. Conjugation is established via copper-catalyzed 1,3-dipolar cycloaddition. Two complementary strategies were employed for conjugation, one involving cycloaddition of amino acid derived azides with ethynyl ferrocene 1 and the other involves cycloaddition between amino acid derived alkynes with ferrocene-derived azides 2 and 3. Labeling of amino acids at multiple sites with ferrocene is discussed. A new route to 1,1,-unsymmetrically substituted ferrocene conjugates is reported. A novel ferrocenophane 19 is accessed via bimolecular condensation of amino acid derived bis-alkyne 9b with the azide 2. The electrochemical behavior of some selected ferrocene conjugates has been studied by cyclic voltammetry.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Investigations on Nanolaminated TiZrN/CrN as a Tribological PVD Hard Coating for Incremental Sheet Forming Tools,ADVANCED ENGINEERING MATERIALS, Issue 8 2009Kirsten Bobzin PVD coated metal forming tools may enormously reduce tool and work piece wear, friction and forming capacities. A PVD deposited TiZrN/CrN + CrN material system is presented for application on incremental sheet forming tools. This work reports on coating process development and tribological investigations leading to a clear friction reduction and wear protection. [source] Nanocomposite Hybrid Molecular Materials for Application in Solid-State Electrochemical Supercapacitors,ADVANCED FUNCTIONAL MATERIALS, Issue 7 2005K. Cuentas-Gallegos Abstract Molecular hybrid materials formed from polyoxometalates dispersed in conducting polymers represent an innovative concept in energy storage. This work reports in detail the first practical realization of electrodes based on these materials for energy storage in electrochemical supercapacitors. The molecular hybrids PAni/H4SiW12O40, PAni/H3PW12O40, and PAni/H3PMo12O40 (PAni: polyaniline) have been prepared electrochemically on platinum or carbon substrates, with PAni/H3PMo12O40 being the prototypical example presenting the best energy-storage performance in the series. This hybrid displays the combined activity of its organic and inorganic components to store and release charge in solid-state electrochemical capacitor cells, leading to a promising value of 120,F,g,1 and good cyclability beyond 1000,cycles. [source] Effects of ultrasound on culture of Aspergillus terreusJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 5 2008Nuria Sainz Herrán Abstract BACKGROUND: Fermentations of Aspergillus terreus are commercially used to produce lovastatin. How ultrasound might influence this fermentation is unknown. While high-intensity ultrasound is effective in disrupting microbial cells, ultrasound of low intensity is known to improve productivity of some fermentation processes without damaging cells. Mechanisms behind productivity improvements have not been clearly identified in earlier studies. This work reports on the effects of ultrasound on A. terreus fermentation for low (957 W m,3), medium (2870 W m,3) and high (4783 W m,3) values of sonication power input in a slurry bubble column sonobioreactor. RESULTS: Sonication at any power level did not affect biomass growth profiles in comparison with negative controls. In contrast, medium- and high-intensity sonication greatly reduced production of lovastatin and substantially altered the growth morphology. At medium and high intensity, ultrasound disrupted fungal pellets and caused the biomass to grow mainly as dispersed hyphae. Sonication affected broth rheology because rheology depends on the morphology of the suspended biomass. CONCLUSION: Sonication can be used to modify growth morphology and broth rheology without affecting growth of filamentous fungi. Sonication appears to influence the primary growth metabolism and secondary metabolism differently in different situations. Copyright © 2008 Society of Chemical Industry [source] PREPARATION AND CHARACTERIZATION OF PEPSIN-SOLUBILIZED TYPE I COLLAGEN FROM THE SCALES OF SNAKEHEAD (OPHIOCEPHALUS ARGUS)JOURNAL OF FOOD BIOCHEMISTRY, Issue 1 2009WENTAO LIU ABSTRACT Pepsin-solubilized collagen prepared from the scales of snakehead (Ophiocephalus argus) was separated into two fractions, major and minor, by NaCl precipitation. The results of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), amino acid composition, and secondary structure showed that the major collagen was typical type I collagen; in contrast, the minor collagen might be classified as type V collagen from the SDS-PAGE patterns and precipitation properties by NaCl. A sharp decrease in solubility of type I collagen was observed at the NaCl concentration of 40 g/L. The maximum and the minimum solubilities of collagen were observed at pH 3 and 8, respectively. Peptide maps of type I collagen digested by trypsin and V8 protease were different from those of calfskin and fish skin collagens. The imino acid content of type I collagen was lower than those of mammalian collagens and so did its denaturation temperature that was 30.3C obtained by viscosity measurement. PRACTICAL APPLICATIONS Collagen has been widely utilized as a material for foods, cosmetics, and pharmaceuticals. However, the use of collagen-derived products from land animals (e.g., bovine and pig) has been called into question because of foot-and-mouth disease crisis etc. Aquatic animal offals, which are readily available and inexpensive, seem to be safe sources for extraction of collagen. This work reports on preparation and characterization of collagen from snakehead scales, which will have potential in supplementing the skins and bones of land animals as an important collagen resource for use in functional food, biomedical, and cosmetic industries. [source] Two new paracetamol/dioxane solvates,a system exhibiting a reversible solid-state phase transformationJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 10 2003Ranko M. Vrcelj Abstract This work reports on the crystal structures of two dioxane solvates of paracetamol that are true polymorphs. The high temperature phase is an orthorhombic form, space group Pbca, Z,=,8, a,=,12.6078(3) Å, b,=,12.1129(2) Å, c,=,13.4138(3) Å, V,=,2048.52(7) Å3, (at 295 K) and the low temperature form is monoclinic, space group P21/c, Z,=,4, a,=,12.325(6) Å, b,=,11.965(4) Å, c,=,13.384(6) Å, ,,=,92.01°, V,=,1972.6(14)Å3 (at 123 K). The structures of these polymorphs are described as is the interrelationship between the two structures. In addition to the structural interrelationship, it is shown that the two forms undergo a reversible phase transformation. Desolvation of either form generates the stable monoclinic phase of paracetamol. © 2003 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 92:2069,2073, 2003 [source] Pneumocystis carinii and Pneumocystis wakefieldiae in Wild Rattus norvegicus Trapped in ThailandTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 2 2010MAGALI CHABÉ ABSTRACT. This work reports for the first time the presence of two Pneumocystis species in wild Rattus norvegicus specimens from Thailand. Pneumocystis DNA was detected in 57.7% (15/26) wild rats without apparent association with typical pneumocystosis. Pneumocystis carinii was found alone in five rats (19.2%), Pneumocystis wakefieldiae was detected alone in six rats (23.1%), and two rats were infected by both species (7.7%). In addition, a new P. wakefieldiae variant sequence has been identified in three wild R. norvegicus specimens caught in the same geographical area. The high frequency of Pneumocystis in wild rats documented in this study and the apparent scarcity of severe pneumocystosis were consistent with an efficient circulation of rat Pneumocystis species in ecosystems. [source] Li-doped nanosized TiO2 powder with enhanced photocalatylic acivity under sunlight irradiationAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 10 2010Soraa Bouattour Abstract This work reports on the synthesis of Li-doped TiO2 nanoparticles using the sol,gel process and solid-state sintering, and investigates their potential use as a photocatalyst for degradation under sunlight excitation of different organic model compounds in aqueous solution. The structure of the nanocrystals was examined by X-ray diffraction, UV-vis ground state diffuse reflectance absorption spectra and X-ray photoelectron emission spectroscopy. Results showed that samples prepared by sol,gel process and calcined at 400 °C are composed of a mixture of anatase and rutile phases, in contrast to the one prepared by solid-state sintering, which exhibits an anatase phase with Li being involved in a spinel phase. The photocatalytic degradation of aqueous solutions of different aromatic compounds was successfully achieved under sunlight excitation in presence of Li-doped TiO2 prepared via sol,gel process. It was shown that the calcination temperature and the preparation mode greatly affect the photocatalytic efficiency. Copyright © 2010 John Wiley & Sons, Ltd. [source] Production of Functional Hepatocyte Growth Factor (HGF) in Insect Cells Infected with an HGF-Recombinant Baculovirus in a Serum-Free MediumBIOTECHNOLOGY PROGRESS, Issue 2 2000Min-Ying Wang Three insect cell lines, SL-7B cells derived from Spodoptera litura, Sf9, and High Five (Hi-5) cells, were used for the production of pro-hepatocyte growth factor (pro-HGF). Cells were cultured and then infected with a recombinant HGF-containing baculovirus in a serum-free medium. In SL-7B cells, pro-HGF is synthesized and excreted from the cells and late in infection is converted to a heterodimeric form of HGF even when the cells are grown in serum free medium. Conversion of a single-chain form of HGF (pro-HGF) into an HGF heterodimer was unexpected, as pro-HGF is normally cleaved by a serum protease called HGF activator. The proliferation activity of heparin-affinity-purified HGF from serum-free culture supernatant of SL-7B cells is comparable to that obtained from HGF converted by serum proteases, suggesting that SL-7B cells produce a functionally analogous protease to correctly process pro-HGF. This work reports, for the first time, on the feasibility of properly processing pro-HGF to form functional HGF by proteases from invertebrate cells in serum-free media. Avoiding the supplementation of sera provides the advantages of a low production cost, zero contamination of infectious agents from sera, and simple downstream product purification. Experimental results further demonstrate that the conversion of pro-HGF by insect cells is cell-line-dependent, because proteases in Hi-5 or Sf9 cells could not process pro-HGF as efficiently and properly as those in SL-7B cells. [source] | ||||||||||||||||