Characterization of some topological semigroups whose level curves are homothetic

We characterize all non-strict Archimedeant-norms whose level curves are homothetic.     

Interaction of opioid molecules with PS,PC and PS/PC monolayers

The interaction between opiate molecules and phosphatidylserine (PS) or phosphatidylcholine (PC) has been studied on compression isotherms and penetration kinetics. Phosphatidylcholine-opiate interactions are weak and similar in magnitude for all opiate molecules. On contrary, PS and PS/PC interact strongly and differently with opiate molecules. The differences in penetration are not directly related to the pKa or hydrophobicity of the molecules.     

Solid-phase syntheses of heterocycles containing the 2-aminothiophenol moiety

Efficient and general procedures have been developed for the solid-phase preparation of substituted benzothiazoles (1), 3, 4-dihydro-1,4-benzothiazines (2), 3,4-dihydro-1,4-benzothiazine-1, 1-dioxides (3), 3,4-dihydro-3-oxo-1,4-benzothiazines (4), and 3, 4-dihydro-3-oxo-1,4-benzothiazine-1,1-dioxides (5). All five classes of compounds were prepared from a common intermediate, resin-bound 2-amino-4-carboxythiophenol, in a minimal number of steps. This intermediate was generated by (i) coupling 4-fluoro-3-nitrobenzoic acid onto Wang resin, or onto an amino acid bound to the resin, (ii) substitution of the aryl fluoride with a protected thiol, (iii) reduction of the nitro group, and (iv) removal of sulfur protection. Reaction with the appropriate substrates and reagents to effect cyclization gave the substituted core structures, which were modified further to introduce additional point(s) of diversity. Following cleavages from the solid support, the compounds were obtained in high initial purities and good isolated yields after purification.     

Interaction of E2 and NS3 synthetic peptides of GB virus C/hepatitis G virus with model lipid membranes

The membrane-interacting properties of two potential epitopes of the GB virus C/Hepatitis G virus, located respectively at the regions (99-118) of the E2 structural protein and (440-460) of the NS3 non-structural protein were studied. Changes in the intrinsic fluorescence of Trp and Tyr residues after the addition of DPPC-LUV revealed that the peptide-membrane interaction was optimal above the gel-liquid crystalline transition temperature of the lipid. Differential scanning calorimetry studies showed that the E2 peptide incorporated into lipid bilayers perturbs the packing of lipids and affects their thermotropic properties. Moreover, the 20-mer structural peptide induced a slow leakage of vesicular contents at 55 degrees C.     

A synthesis of multidimensional judgements consistent with linear transformations

Summary We give a characterization of the weighted arithmetic mean onR ⁿ by solving a functional equation motivated by a problem of synthesizing multidimensional judgements consistent with nonsingular linear transformations.Dedicated to the memory of Alexander M. Ostrowski on the occasion of the 100th anniversary of his birth.     

Solid-phase synthesis of constrained terminal and internal lactam peptidomimetics

Lactams are key components of many peptidomimetic structures. Five- and six-membered lactam peptidomimetics with hydrogen or amino acid side chains at the alpha-position can be constructed from peptide precursors during a solid-phase synthesis. There is no significant racemization of remote stereocenters during synthesis.     

Effects of overlapping GB virus C/hepatitis G virus synthetic peptides on biomembrane models

The present study was undertaken to examine the physicochemical properties of three overlapping peptides belonging to the E2 envelope protein of Hepatitis G virus (GBV-C/HGV) and its interaction with phospholipid biomembrane models using biophysical techniques. We describe our findings concerning the surface activity and the interaction of the peptides with monolayers and liposomes composed of the zwitterionic phospholipids dipalmitoylphosphatidylcholine and dimyristoylphosphatidylcholine (DMPC) and a mixture of DMPC with the anionic phospholipid dimyristoylphosphatidylglycerol. The results inform about the effect of the chain length on their interaction with biomembrane models. The longest chain peptide interacts in a higher extent with all the phospholipid studied as a result of a combination of hydrophobic and electrostatic forces.     

Modification of phosphatidylcholine-opiates interaction by different buffers

The influence of subphase composition and ionic strength on the interaction between opiate molecules and phosphatidylcholine has been studied. Results show that a neutral pH favours the penetration of opiate molecules in phosphatidylcholine monolayers, but the ionic strength and the chemical nature of buffer components affect also greatly these interactions. The results could explain, in part the differences in opioid binding values observed for different buffers.