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61.
Three hydrophobic derivatives of GHK peptide containing either N-terminal hexanoyl, decanoyl or myristoyl acyl moieties were synthesized. The binding of these peptidolipids to phospholipid bilayers as well as their hemolytic activity were determined. Moreover, the influence of these peptidolipids on several physicochemical properties of liposomes was studied. Binding experiments indicate a high affinity of these peptidolipids for lipids ordered in liposomes. Nevertheless, this interaction does not promote the release of entrapped carboxyfluorescein. Experiments carried out by the asymmetric membrane method (NBD-PE/dithionite) and quenching studies (PC-pyrene/KI) indicate that this association has a protective effect suggesting that the hydrophobic moiety inserts in the external part of the bilayer and the peptide chain remains protruding from the surface hindering the entrance or the approach of reactants to it. The microviscosity of DPPC bilayers determined using TMA-DPH as fluorescent marker was not affected by the presence of peptidolipids. Besides, results indicate that myristoyl-GHK produces total hemolysis at 2.5 × 10−4 M but decanoyl and hexanoyl derivatives at 5 × 10−4 M induce only 10% of hemolysis. 相似文献
62.
Problems on associative functions 总被引:1,自引:0,他引:1
63.
64.
J.A.H. Stotz F. Alsina R. Hey P.V. Santos 《Physica E: Low-dimensional Systems and Nanostructures》2005,26(1-4):67
Mobile potential dots (dynamic dots, DDs) formed by surface acoustic waves (SAWs) are used to transport photogenerated electrons and holes in GaAs quantum wells (QWs). We investigate the interaction between the transported carriers and microscopic trap centers in the QW plane using spatially and time-resolved photoluminescence (PL) spectroscopy. The carriers recombine at the trap site emitting short (width0.6 ns) light pulses at a repetition rate corresponding to the SAW frequency. The dependence of the PL intensity from the traps on the number of carriers transported per DD n exhibits a well-defined, distinct plateau for n in the range from 5–20, which is attributed to the emission of a well-defined number of photons. 相似文献
65.
Ippolito Antonini Mario Cardellini Francesco Claudi Palmarisa Franchetti Franco Micheletti Moracci 《合成通讯》2013,43(14):1229-1232
Stereoselective one-step synthesis of 4-alkoxy-1-ethoxycarbonylmethylazetidin-2-ones from acid chlorides and N-ethoxycarbonylmethylimidates. 相似文献
66.
Claudi Alsina 《Rendiconti del Circolo Matematico di Palermo》1985,34(1):136-140
We characterize all non-strict Archimedeant-norms whose level curves are homothetic. 相似文献
67.
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. 相似文献
68.
M. A. Alsina C. Mestres G. Valencia J. M. García Antón F. Reig 《Colloid and polymer science》1988,266(9):832-835
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. 相似文献
69.
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. 相似文献
70.
Claudi Alsina 《Aequationes Mathematicae》1991,41(1):94-102
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. 相似文献