涤纶用色母料和功能母料

全球涤纶产量不断创下新的增长记录.2006年,全球涤纶产量超过2 700万t,占合成纤维总产量的67%.除了传统用途外,涤纶的应用领域在不断扩大,包括许多特殊应用领域,这就需要对纤维的性能加以提高和改造.除了色彩外,车用和户外纺织品、功能服装、运动装、袜子、医疗/卫生纺织品及许多其他纺织应用领域还需要防紫外线、抗菌、阻燃和防污等多种特殊功能.纳米材料所赋予的性能为涤纶开辟了新的应用领域.     

Explicit adaptive Runge-Kutta methods

When solving stiff problems the efficiency of the Runge-Kutta methods can be substantially improved if the parameters of the integration formula are adjusted to the problem at hand. The construction of such methods called adaptive is considered. The results obtained on test problems are compared with those obtained by known methods.     

The concept of synergism in radiobiology]

We have demonstrated previously that pemphigus vulgaris (PV)-IgG induces activation of phospholipase C (PLC), production of inositol 1,4,5-trisphosphate, and a rapid transient increase in [Ca2+]i in cultured human keratinocytes, leading to secretion of plasminogen activator and cell-cell detachment in cell culture. In the current study, to examine the involvement of protein kinase C (PKC) in the mechanism of blister formation in PV, we studied the PV-IgG-induced translocation of PKC isozymes from the cytosol to the particulate/cytoskeleton (p/c) fractions and the activation of PKC in human keratinocytes. Cells cultured in Eagle's minimum essential medium were incubated with PV-IgGs for 30 s, 1 min, 5 min, or 30 min. PV-IgG binding to the cell surface antigen (desmoglein III) induced translocation of PKC-alpha from the cytosol to the p/c fractions within 30 s, with a peak at 1 min that lasted at least 30 min. PKC-delta also was translocated within 1 min and reached a peak at 5 min but was reduced to basal levels at 30 min. Alternatively, PKC-eta translocation to the p/c fraction was induced slowly, taking more than 5 min, and was reduced to approximately half-maximum at 30 min, whereas PKC-zeta translocation reached a maximum at 30 s, rapidly returning to baseline by 5 min after PV-IgG stimulation. The total PKC activity in the p/c fraction also was increased after PV-IgG exposure, peaked at 1 min, and was sustained for at least 30 min. These findings suggest that a unique activation profile of PKC isomers may be involved in mediating the intracellular signaling events induced by PV-IgG binding to desmoglein III in cultured human keratinocytes.     

Monitoring of Radionuclide Impurities in <Superscript>166</Superscript>Ho-Albumin Microspheres Prepared by Neutron Activation with Thermal Neutrons

Analysis of radionuclide impurities in ¹⁶⁶Ho-albumin microspheres prepared by activation with thermal neutrons of ¹⁶⁵Ho preliminarily incorporated in the particle matrix was performed. The content of impurities in the final product was determined by γ-ray spectroscopy. With ¹⁶⁶Ho-albumin microspheres as example, an algorithm was developed for evaluation of the radiochemical purity of the preparation. It was found that the radiochemical purity of the preparation, which is primarily determined by impurities of rare-earth elements, can be estimated from the content of ^152m Eu.__________Translated from Radiokhimiya, Vol. 47, No. 3, 2005, pp. 278–280.Original Russian Text Copyright © 2005 by Petriev, Skvortsov, Smakhtin, Shutova.     

A strain of the yeast Saccharomyces cerevisiae for testing environmental mutagens based on interaction of the mutations rad2 and him1

The interaction between mutations at the RAD2 and HIM1 genes was studied. The RAD2 gene encodes endonuclease involved in nucleotide excision repair. Mutants at this gene are highly sensitive to the lethal effect of a variety of mutagens. The product of the HIM1 gene is needed for correction of mismatched bases and repair of premutational DNA damage. Mutations in this gene lead to the formation of the mutator phenotype and high sensitivity to induced mutagenesis. The double rad2 him1 mutant manifested the synergic type of interaction. The level of UV-induced mutagenesis in the double mutant was five times higher than in single mutants, and the absolute yield of forward mutations in five genes controlling adenine biosynthesis was 1 to 2%. UV-induced mutagenesis was increased, at low doses, by several orders of magnitude in the double mutant, compared to the wild-type strain. The high level of mutagenesis in this mutant was caused by ethyl and methyl methanesulfonate. These properties of the stock with the double rad2 him1 mutation makes it promising as a tester in analysis of the gene toxicity of different substances.     

Modeling of a three-dimensional structure of cytochrome P-450 1A2 and search for its new ligands

The substances inhibiting cytochrome P450 1A2 (CYP1A2) represent a perspective class of new drugs, which application in clinical practice can become the important part in preventive maintenance in oncology. The present work is devoted to computer modelling of 3-D structure of CYP1A2 and searching of new inhibitors by database mining. The modelling of CYP1A2 was done based on homology with 4 bacterial cytochromes P450 with known 3-D structure. For optimization of CYP1A2 active site structure the models of its complexes with characteristic substrates (caffeine and 7-ethoxyresorufin) were designed. These complexes were optimized by molecular dynamics simulation in water. The models of 24 complexes of CYP1A2 with known ligands with known Kd were designed by means of DockSearch and LeapFrog programs. 3D-QSAR model with good predictive force was created based on these complexes. On a final stage the search of knew CYP1A2 ligands in testing database (more than 23.000 substances from database Maybridge and 112 known CYP1A2 ligands from database Metabolite, MDL) was executed. 680 potential ligands of CYP1A2 with Kd values, comparable with known ones were obtained. This number has included 73 compounds from 112 known ligands, introduced in tested database as the internal control.