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Linear Counterparts (linear + counterpart)
Selected AbstractsStructural studies and model membrane interactions of two peptides derived from bovine lactoferricinJOURNAL OF PEPTIDE SCIENCE, Issue 7 2005Leonard T. Nguyen Abstract The powerful antimicrobial properties of bovine lactoferricin (LfcinB) make it attractive for the development of new antimicrobial agents. An 11-residue linear peptide portion of LfcinB has been reported to have similar antimicrobial activity to lactoferricin itself, but with lower hemolytic activity. The membrane-binding and membrane-perturbing properties of this peptide were studied together with an amidated synthetic version with an added disulfide bond, which was designed to confer increased stability and possibly activity. The antimicrobial and cytotoxic properties of the peptides were measured against Staphylococcus aureus and Escherichia coli and by hemolysis assays. The peptides were also tested in an anti-cancer assay against neuroblastoma cell lines. Vesicle disruption caused by these LfcinB derivatives was studied using the fluorescent reporter molecule calcein. The extent of burial of the two Trp residues in membrane mimetic environments were quantitated by fluorescence. Finally, the solution NMR structures of the peptides bound to SDS micelles were determined to provide insight into their membrane bound state. The cyclic peptide was found to have greater antimicrobial potency than its linear counterpart. Consistent with this property, the two Trp residues of the modified peptide were suggested to be embedded deeper into the membrane. Although both peptides adopt an amphipathic structure without any regular ,-helical or ß-sheet conformation, the 3D-structures revealed a clearer partitioning of the cationic and hydrophobic faces for the cyclic peptide. Copyright © 2004 European Peptide Society and John Wiley & Sons, Ltd. [source] V-Shaped Thiophene-Based Oligomers with Improved Electroluminescence Properties,ADVANCED FUNCTIONAL MATERIALS, Issue 4 2005G. Barbarella Abstract The synthesis via the Stille coupling of a new family of oligomers derived from benzo[b]thiophene is reported. Owing to their branched molecular structure lacking any symmetry element, these compounds display a low tendency to crystallization and better film-forming properties than their linear counterparts. Spin-coated films show photoluminescence efficiencies up to 50,%. Light-emitting diodes with spin-coated films as the active layers display markedly improved performance with respect to similar devices based on linear oligothiophenes, with luminance values up to more than 10,000,cd,m,2. Semiempirical PM3 and ZINDO/S calculations provide insight into the molecular geometries and electron distribution of the frontier orbitals of the new compounds. Cyclic voltammetry data indicates that the transformation of the thienyl sulfur of benzo[b]thiophene to the corresponding thienyl- S,S -dioxide leads an increase in electron affinity by 0.5,0.7,V, analogous to that of the corresponding linear oligomers. [source] The performance of non-linear exchange rate models: a forecasting comparisonJOURNAL OF FORECASTING, Issue 7 2002Gianna Boero Abstract In recent years there has been a considerable development in modelling non-linearities and asymmetries in economic and financial variables. The aim of the current paper is to compare the forecasting performance of different models for the returns of three of the most traded exchange rates in terms of the US dollar, namely the French franc (FF/$), the German mark (DM/$) and the Japanese yen (Y/$). The relative performance of non-linear models of the SETAR, STAR and GARCH types is contrasted with their linear counterparts. The results show that if attention is restricted to mean square forecast errors, the performance of the models, when distinguishable, tends to favour the linear models. The forecast performance of the models is evaluated also conditional on the regime at the forecast origin and on density forecasts. This analysis produces more evidence of forecasting gains from non-linear models. Copyright © 2002 John Wiley & Sons, Ltd. [source] Cyclic polymers: Synthetic strategies and physical propertiesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 2 2010Hans R. Kricheldorf Abstract Syntheses of cyclic polymers including cyclic homopolymers, cyclic block copolymers, sun-shaped polymers, and tadpole polymers are discussed on the basis of a differentiation between synthetic methods and synthetic strategies (e.g., polycondensation, ring,ring equilibration, or ring-expansion polymerization). Furthermore, all synthetic methods are classified as kinetically or thermodynamically controlled reactions. Characteristic properties of cyclic polymers such as smaller hydrodynamic volume, lower melt viscosities, and higher thermostabilities are compared to the properties of their linear counterparts. Furthermore, the nanophase separation of cyclic diblock copolymers is discussed. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 251,284, 2010 [source] | ||||||||||