The effect of oxidative stress on structural transitions of human erythrocyte ghost membranes

The influenza virus hemagglutinin (HA) contains three highly conserved cysteine residues at positions 551, 559, and 562 close to the carboxyl-terminus of the HA2 subunit which serve as palmitylation sites. Wild-type HA of influenza virus A/FPV/Rostock/34 (H7N1) and HA permutated by exchange of the acylated cysteine to serine residues were expressed in CV-1 cells by a SV40 vector system. Since density of immunostained HA on the cell surface measured by flow cytometric analysis did not differ between wild-type and acylation mutants, it was possible to compare acylation mutants and wild-type HA for their capacity to induce membrane fusion at low pH. The following observations were made: (1) lateral diffusion of a lipid-like fluorophore (R-18) from the erythrocyte membrane to the plasma membrane of cells expressing HA on the surface occurred equally well with mutants and wild type. (2) Diffusion of a low-molecular-weight fluorescent water-soluble probe (calcein) from erythrocytes into the cytoplasm of HA-expressing cells was not altered either. (3) However, depending on the position and the number of the deleted acylation sites, the mutants showed a reduced ability to induce syncytia. The data indicate that deacylation of the cytoplasmic tail has no measurable effect on the capacity of HA to induce membrane fusion and pore formation but that it suppresses syncytia formation.     

Mathematical models of the battle between parties for electorate or between companies for markets

A model of optimization of strategies for any number of political parties (companies) in election (advertising) campaigns is proposed. We formulated the problem of choosing an optimal strategy for allocating scarce resources among regions (markets) in which political parties (companies) have different influences. The optimization model is analyzed and the existence of a unique solution is proved for different functions of dependencies between investments and winning. An analytical solution to the model is found for the case of two parties (companies). A direction for further development is the study of the sensitivity of an optimal solution to model parameters and formation of a stochastic model.     

Synthesis of amphiphilic (meth)acrylates with oligo(ethylene glycol) and (or) oligo(propylene glycol) blocks by the esterification of (meth)acrylic acid

Thermoresponsive PEG-based (PEG stands polyethylene glycol) polymers are unique for use in medicine because of their low toxicity, good biocompatibility and biodegradability, but usually more hydrophobic and more toxic comonomers are used to adjust lower critical solution temperature (LCST). A convenient way to overcome this problem and to finely tune LCST is to use alkoxy oligo(ethylene glycol)- or alkoxy oligo(propylene glycol) (meth)acrylates as starting comonomers. Here we report on the conditions for the simple and affordable synthesis of methoxy oligo(propylene glycol) (meth)acrylate- and methoxy oligo(propylene glycol)-block-oligo(ethylene glycol) (meth)acrylate-based macromonomers with high yields (80%–98.7%) by the acid-catalyzed esterification of (meth)acrylic acid with alkoxy oligo(alkylene glycols) containing oligo(ethylene glycol) (OEG) and/or oligo(propylene glycol) (OPG) blocks. p-Toluene sulphonic acid (pTSA), alkyl(C₁₂–C₁₄)benzene sulfonic acid (ABSA) and H₂SO₄ were used as catalysts. It has been shown that pTSA and ABSA are practically the same in catalytic activity and are superior to sulfuric acid. The reaction orders with respect to catalyst was found to be close to 1 in all cases. It has been shown that the reaction is actually insensitive to the lengths of OEG and OPG blocks, as well as to the structure of the terminal alkyl group, while the esterification of acrylic acid (AA) proceeds much faster compared to methacrylic acid (MAA) one under the same conditions. The influence of temperature on the equilibrium conversions of alcohols was determined, which were found to be 89%–93% for the esterification of AA and 61%–86% for MAA in the temperature range of 60–120°C. A further increase in conversion was achieved by introducing an azeotropic agent (toluene), its optimal concentration was found to be 10%–15%.     

Technological indicators of different schemes for accumulating heat in soil

Results from analyzing the operation of heat exchangers for accumulating heat in soil are presented. Indicators characterizing their performance when placed in the accumulating strata in single-and group-wise manners are compared.     

Beryllium Analytical Signal Using ERIAD Mass-Spectrometry for Various Sample Preparation Methods

Inorganic Materials - The significance of the problem of determining the concentration of beryllium in solutions is substantiated. A method of ERIAD mass-spectrometry (atmospheric pressure...     

Raman scattering of InAs/AlAs quantum dot superlattices grown on (001) and (311)B GaAs surfaces

ABSTRACT: We present a comparative analysis of Raman scattering by acoustic and optical phonons in InAs/AlAs quantum dot superlattices grown on (001) and (311)B GaAs surfaces. Doublets of folded longitudinal acoustic phonons up to the fifth order were observed in the Raman spectra of (001)- and (311)B-oriented quantum dot superlattices measured in the polarized scattering geometries. The energy positions of the folded acoustic phonons are well described by the elastic continuum model. Besides the acoustic phonons, the spectra display features related to confined transverse and longitudinal optical as well as interface phonons in quantum dots and spacer layers. Their frequency positions are discussed in terms of phonon confinement, elastic stress, and atomic intermixing.     

Investigation into the state of metal during radial-shear rolling on a SRVP-130 mill

Radial-shear rolling (RSR) plays an important role in the production of titanium alloys in OAO VSMPO-AVISMA (Verkhn. Salda), having a number of advantages over other processes of metal formation. A software complex for modeling formation and heat transfer in the metal volume has been developed during this investigation on the basis of engineering computation techniques, and the rolling of a bar of the VT6 alloy with a diameter of 155 mm has been studied using it. The ThemoRSR program, making it possible to image computational data in the Mathcad environment, is developed; rolling is modeled with a DEFORM-3D package; and conditions of its application are shown. Promising methods for measuring the rolling temperature and the torsion torque on a mill spindle are considered.     

MedISys: An early-warning system for the detection of (re-)emerging food- and feed-borne hazards

We evaluated the Medical Information System (MedISys) as an early-warning system for the detection of food- and feed-borne hazards. Nine hazards were selected in the period from January 2007 to March 2009 from the Rapid Alert System for Food and Feed (RASFF) and traced back on MedISys and ProMED-mail. In addition, from January to March 2009, food- and feed-borne (re-)emerging hazards were monitored on MedISys and traced back on ProMED-mail and RASFF. MedISys has demonstrated to be an effective early-warning system for food- and feed-borne hazards. However, further customization is required to improve its sensitivity, in particular by increasing the number of multi-lingual categories related to food and feed items. MedISys tended to detect food- and feed-borne hazards earlier and more frequently than ProMED-mail, but the information from both systems was often complementary.     

Results of U<Subscript>0.55</Subscript>Pu<Subscript>0.45</Subscript>N and U<Subscript>0.4</Subscript>Pu<Subscript>0.6</Subscript>N mixed mononitride fuel tests in a bor-60 reactor to burnup 12% h.a.

The results of post-reactor studies of U_0.55Pu_0.45N and U_0.4Pu_0.6N mixed mononitride fuel elements (density 85% of the theoretical value) and a helium sublayer are presented. The fuel elements are irradiated in a BOR-60 reactor to burnup 9.4 and 12.1% h.a., respectively, with power density 430 and 540 W/cm. All fuel elements remained hermetic; the ChS-68 steel cladding (20% cold deformation) retained excess plasticity. The maximum zone of interaction between the cladding and the fuel and fission products did not exceed 15 μm. The swelling rate of U_0.4Pu_0.6N and U_0.55Pu_0.45N fuel was 1.1 and 0.68%/% burnup, respectively. The gas release did not exceed 19.3 and 19%. The steel damage dose was 43 dpa. The character of the porosity distribution in the fuel affects the swelling and gas release.     

Thermal Evolution of Solid Products Derived from Germanium-Containing Preceramic Polymer

The products formed during thermolysis of poly(germasilethyne) have been studied within temperature range 20–1600°C by means of Raman spectroscopy, XRD and EDS analysis, and SEM analysis. The evolution of solid products derived from poly(germasilethyne) as a function of heat-treatment temperature passes through several stages. At earlier stages the cross-linking of polymer molecules and the formation of rigid three-dimensional network occur. The particularity of the first stage of thermal transformation of poly(germasilethyne) in comparison with silicon analogue is not only the formation of the skeleton in the solid phase but also the release of disordered carbon phase. The stage of intensive thermal decomposition of germanium-containing polymer includes the escape of gaseous products, the formation of strongly disordered carbon, amorphous covalent silicon–germanium-carbon network and germanium as inorganic phase (most likely Si_1–x–yGe_xC_y). High-temperature treatment results in the evaporation of germanium, the formation and ordering of carbon and -SiC phases. The presence of germanium in the products of thermolysis of polymer leads to a faster growth of the oxides during exposition of thermolyzed polymer to air at high temperatures.