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Many Research Groups (many + research_groups)
Selected AbstractsUsing Metallo-Supramolecular Block Copolymers for the Synthesis of Higher Order Nanostructured AssembliesMACROMOLECULAR RAPID COMMUNICATIONS, Issue 1 2010Adam O. Moughton Abstract Many research groups have explored the properties and solution self-assembly of main chain metallo-supramolecular multiblock copolymers. Until recently, these metal complexes have been used to prepare mainly micelle type structures. However, the self-assembly of such copolymers has been exploited further to create more advanced architectures which utilize the reversible supramolecular linkage of their building blocks as a key component in their synthesis. Furthermore, the incorporation of multiple orthogonal interactions and stimuli responsive polymers into their design, enables more precise external control of their properties. This feature article discusses recent developments and provides an insight into their potential exploitation and development for the creation of novel, smart, and responsive nanostructures. [source] Molecular Tools to Study Physcomitrella patensPLANT BIOLOGY, Issue 3 2005W. Frank Abstract: The moss Physcomitrella patens has become a suitable model plant system for the analysis of diverse aspects of modern plant biology. The research strategies have been influenced by the implementation of state-of-the-art cell culture and molecular biology techniques. The forthcoming completion of the Physcomitrella genome sequencing project will generate many open questions, the examination of which will rely on a diverse set of molecular tools. Within this article, we intend to introduce the essential cell culture and molecular biology techniques which have been adopted in recent years to make Physcomitrella amenable to a wide range of genetic analyses. Many research groups have made valuable contributions to improve the methodology for the study of Physcomitrella. We would like to apologise to all colleagues whose important contributions could not be cited within this manuscript. [source] Quantitative identification of protein nitration sitesPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 6 2009Giovanni Chiappetta Abstract Several labelling strategies have been developed targeting specific amino acid residues and/or PTMs. Methods specifically tailored for the qualitative and sometimes quantitative determination of PTMs have emerged. Many research groups have focused their attention towards o-nitrotyrosine residues, developing various methodologies for their identification, while direct quantification has remained elusive. So far the iTRAQ chemistry has been limited to primary amines. Here, we report a new strategy based on the use of iTRAQ reagents coupled to MS analysis for the selective labelling of o-nitrotyrosine residues. This method was proved to lead to the simultaneous localisation and quantification of nitration sites both in model proteins and in biological systems. [source] Thermal Rearrangements of Monoterpenes and MonoterpenoidsHELVETICA CHIMICA ACTA, Issue 9 2009Achim Stolle Abstract The thermal conversions of monoterpenes and monoterpenoids are an interesting field of research with respect to mechanistic, kinetic, and theoretical issues. Since the beginning of the 20th century, these reactions have attracted the interest of many research groups, and even today there are sufficient problems and questions to deal with. This review covers the thermal isomerization chemistry of pinanes, pinenes, carenes, and thujenes over the past 70 years. Categorization of these compounds into groups, each of them being represented by a small parent molecule (cyclobutane, vinylcyclobutane, vinylcyclopropane), allows systematization of multitude of publications. [source] Separation and quantification of 9-(alkylthio)acridines by capillary micellar electrokinetic chromatography and capillary liquid chromatographyJOURNAL OF SEPARATION SCIENCE, JSS, Issue 13 2007Jana Nejmanová Abstract Various thioacridine derivatives are potential chemotherapeutics against various diseases which are intensively synthesized, characterized, and investigated by many research groups. Efficient, fast, and reliable separation and quantification methods for their analysis are still to be developed. MEKC and capillary LC (CLC) were applied for the separation and quantification of five highly hydrophobic, weakly basic, and structurally similar 9-(alkylthio)acridines. Since the common anionic and cationic surfactants failed to separate the strongly hydrophobic thioacridines by MEKC, sodium cholate was used in an alkaline BGE and successfully employed for their fast separation. In CLC, the weakly basic nature of the thioacridines necessitated use of LiChrosorb RP-select B sorbent as the stationary phase, which combined with a very simple mobile phase methanol/water yielded an efficient chromatographic separation system. Both, the MEKC and CLC optimized separation methods were then applied to quantify the thioacridines within a concentration range of 1.0×10,5,1.0×10,3 mol/L and the obtained experimental results were critically compared. In practical terms, the MEKC analytical method can quantify the analytes much faster but with a lower reliability while the CLC method performs slower analysis with a higher repeatability of the experimental results. [source] Dimensions of reengineering environment infrastructuresJOURNAL OF SOFTWARE MAINTENANCE AND EVOLUTION: RESEARCH AND PRACTICE, Issue 5 2003S. Ducasse Abstract Over the last decade many research groups and commercial companies have been developing reengineering environments. However, many design decisions such as support for multiple models, incremental loading of information, tool integration, entity grouping, and their impacts on the underlying meta-model and resulting environment have remained implicit. Based on the experience accumulated while developing the Moose reengineering environment and on a survey of reengineering environments, we present a design space defined by a set of criteria that makes explicit the different options and especially their dependencies and trade-offs. Using this design space, developers of future environments should have a better understanding of the problems they face and the impact of design choices. Copyright © 2003 John Wiley & Sons, Ltd. [source] Preparation and characterization of polyurethane,gold nanocomposites prepared using encapsulated gold nanoparticlesPOLYMER INTERNATIONAL, Issue 7 2010Chao-Ching Chang Abstract Gold nanoparticles (GNPs) have been widely studied due to their unique properties. Although many research groups have developed the synthesis of GNPs using various polymers as stabilizing or reducing agents, the effects of GNPs on the structures and properties of polymer matrices have been less reported. We propose a new design for the preparation of polyurethane,gold (PU,Au) nanocomposites. 11-Mercapto-1-undecanol-coated GNPs acted as the chain extenders and reacted with isocyanates to form covalent bonds between PU and GNPs. PU,Au nanocomposites were successfully synthesized, and the effects of multifunctional GNPs on the structures, morphology and properties of poly(ester urethane) were investigated. Scanning electron microscopy images suggested the GNPs can be dispersed uniformly in the PU matrix. Maltese-cross of spherical crystals was observed in the PU,Au nanocomposites, and the size of the crystals decreased with an increase in gold content. As the gold content increased, the thermal decomposition temperature and the temperature of the maximum decomposition rate increased. The glass transition temperature, crystal melting temperature and melting enthalpy of the soft segment also increased progressively. The results showed that multifunctional GNPs concentrated hard segments and resulted in an increase of heterogeneous nucleation, phase separation and elasticity. Copyright © 2010 Society of Chemical Industry [source] The biomolecule ubiquinone exerts a variety of biological functions,BIOFACTORS, Issue 1-4 2003Hans Nohl Abstract The chemistry of ubiquinone allows reversible addition of single electrons and protons. This unique property is used in nature for aerobic energy gain, for unilateral proton accumulation, for the generation of reactive oxygen species involved in physiological signaling and a variety of pathophysiological events. Since several years ubiquinone is also considered to play a major role in the control of lipid peroxidation, since this lipophilic biomolecule was recognized to recycle ,-tocopherol radicals back to the chain-breaking form, vitamin E. Ubiquinone is therefore a biomolecule which has increasingly focused the interest of many research groups due to its alternative pro- and antioxidant activity. We have intensively investigated the role of ubiquinone as prooxidant in mitochondria and will present experimental evidences on conditions required for this function, we will also show that lysosomal ubiquinone has a double function as proton translocator and radical source under certain metabolic conditions. Furthermore, we have addressed the antioxidant role of ubiquinone and found that the efficiency of this activity is widely dependent on the type of biomembrane where ubiquinone exerts its chain-breaking activity. [source] 3121: Oxygen and treatment of ocular ischemic diseasesACTA OPHTHALMOLOGICA, Issue 2010E STEFANSSON Purpose In ischemia, reduced blood flow results in hypoxia. Hypoxic cells make hypoxia inducible factor (HIF), which controls many of the adaptive responses of tissue to ischemia. This includes vasodilatation, production of vascular endothelial factor (VEGF) with neovascularization and leakage, and finally apoptosis and tissue atrophy. Methods If hypoxia is improved this will reduce the production of VEGF and thereby reduce new vessel formation on one hand and vascular leakage and edeam formation on the other. Several methods are available to improve retinal hypoxia, including laser treatment, vitrectomy, vasodilatory drugs such as carbonic anhydrase inhibitors in addition to breathing oxygen. These treatment methods have been studied by many research groups with invasive polarographic electrodes and optical probes as well as noninvasive oxymetry in human patients and animal subjects. Results We will review experimental and clinical studies, which confirm that oxygen tension of the retina is increased following 1. retinal laser treatment 2. Vitrectomy 3. carbonic anhydrase inhibitors Conclusion Oxygen is the natural control of VEGF. VEGF levels in the retina and other ocular tissues are affected by oxygen levels and ischeimc diseases are currently treated with methods that affect oxygen and consequently VEGF. The addition of anti VEGF drugs to oxygen directed treatment such as laser and vitrectomy further influences the oxygen-HIF-VEGF-neovascularization/edema axis in ischemic retinopathies. [source] | ||||||||||||||||