Poly(hydroxybutyrate‐co‐hydroxyvalerate) and bovine serum albumin blend prepared by electrospinning

Electrospinning is a method for the preparation of nanosized polymer fibers. Here, electrospinning is used to prepare a blend of a polyester, poly(hydroxybutyrate‐co‐hydroxyvalerate) (PHBV), and a globular protein, bovine serum albumin (BSA). The electrospun blend film is compared with a solution‐cast blend film and with single‐component electrospun films made of PHBV and BSA. In the electrospun blend films, BSA manifests itself as flat ribbons and a fine network formed from fibers less than 50 nm in diameter. The dissolution rate of BSA from the electrospun blended film is lower than from the solution‐cast one. The films are characterized using scanning electron microscopy, differential scanning calorimetry, and contact‐angle measurements. The obtained PHBV+BSA blend films have several emergent properties: a slow BSA dissolution rate, a fine BSA network, and unusual thermal behavior. Thus, the PHBV+BSA blend films introduce a new class of polymer–protein blends. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45090.     

Biochemistry and hematology at decompression sickness: a case report

A 24-year-old hospital corpsman, a volunteer in a series of dry chamber air dives to a simulated pressure equivalent to 188 FSWG (57.3 MSWG), developed left knee pain shortly after standard decompression. A tentative diagnosis of decompression sickness was made and recompression therapy was initiated with alleviation of pain occurring at 60 FSWG (18.3 MSWG). A U.S. Navy Treatment Table "5 (oxygen breathing) regimen was then selected and completed uneventfully. The subject had been undergoing biomedical evaluation for several days prior to diving; thus, a clinically diagnosed case of dysbarism with subsequent treatment was available for study. This individual was then monitored for a 10-d period. The acute phase of decompression sickness was characterized by a marked shortening of clotting time and a thrombocytopenia with accompanying increased platelet aggregates. The recovery phase was categorized by a variety of hematological and bio-chemical changes. Hemodilution, an elevated megathrombocyte index, and a tendency toward eosinopenia were evident for most of the 10-d observation period. Other persistent alterations detected during this period included a relative hyperglycemia, depressed urine Na+/K+, and increased ketosteroid excretion. These observations indicate that abatement of pain after treatment of dysbarism can be followed by the onset of a variety of biochemical and hematological changes. Moreover, complete recovery may require upwards of 10 d.     

Heat-resistant concrete based on aluminothermic slags of the Klyuchevskii Ferroalloys Plant

Substance and grain compositions, parameters of physicochemical properties, and ranges of application of heat-resistant concretes produced on the basis of aluminothermic slags are presented. A wide range of fillers and lime-aluminate cements of refractory and heat-resistant concretes is considered. Experience in the use of slag concretes in linings of various heating units is described. __________ Translated from Novye Ogneupory, No. 12, pp. 15–18, December, 2007.     

Effect of synthesis conditions and surrounding medium on luminescence properties of YVO4:Eu3+nanopowders

Nanocrystalline yttrium vanadate doped with europium ions powders were synthesized via sol-gel method based on decomposition of metal-polymer complex. X-ray diffraction analysis showed that samples had pure tetragonal phase without any impurities. Scanning electron microscopy and static light scattering technique were used to study morphology and size of prepared nanoparticles. Average diameter of the nanoparticles was about 40 nm. The changes in structural and luminescence properties were observed as a function of the first and second calcination temperature. The optimal conditions for synthesis of nanoparticles were determined as Т1=500 °С, t1=1 h; Т2=950 °С, t2=1.5 h. The effect of different media surrounding the nanoparticles on their luminescence properties and lifetime was investigated and discussed in terms of effective refractive index. It was found that the observed lifetime of YVO4:Eu3+ 5 at.% nanophosphor was decreased from 0.64 ms in air(nmed=1) to 0.45 ms in chalcogenide glass As39S61(nmed=2.39).     

Self-assembly of charged microclusters of CdSe/ZnS core/shell nanodots and nanorods into hierarchically ordered colloidal arrays

A thermodynamically driven self-organization of microclusters of semiconductor nanocrystals with a narrow size distribution into periodic two-dimensional (2D) arrays is an attractive low-cost technique for the fabrication of 2D photonic crystals. We have found that CdSe/ZnS core/shell quantum dots or quantum rods, transferred in aqueous phase after capping with the bifunctional surface-active agent DL-cysteine, form on a poly-L-lysine coated surface homogeneously sized micro-particles, droplet-like spheroid clusters and hexagon-like colloidal crystals self-organized into millimetre-sized 2D?hexagonal assemblies. The presence of an organic molecular layer around the micro-particles prevents immediate contact between them, forming an interstitial space which may be varied in thickness by changing the origin of the molecular layer capping nanocrystals. Due to the high refractive index of CdSe and the low refractive index of the interstitial spaces, these structures are expected to have deep gaps in their photonic band, forming hierarchically ordered 2D arrays of potentially photonic materials.     

Halogen anion formation in 5-halouracil films: X rays compared to subionization electrons

The radiosensitization properties of 5-halouracils (5-FU, 5-BrU and 5-IU), i.e. the enhanced sensitivity of biological media containing these compounds to ionizing radiation, have been studied using surface science methods. We show that soft X rays and near 0 eV electrons both induce dissociation of 5-halouracils into a halogen anion and a uracilyl radical. The yield of anions from 5-FU is much smaller than that from the bromo- and iodo-analogs. We explain the high anion yields in 5-BrU and 5-IU with dissociative electron attachment (DEA) of near 0 eV electrons. The thermodynamic threshold for DEA to 5-FU is near 2 eV and therefore prohibits dissociation by near 0 eV electrons.     

The separate effects of E60Q in Lactobacillus casei thymidylate synthase delineate between mechanisms for formation of intermediates in catalysis

X-Ray crystal structures of Lactobacillus casei thymidylate synthase (TS) mutant complexes of E60D with dUMP, and E60Q with dUMP or FdUMP, as well as ternary complexes with folate analog inhibitor CB3717, are described. The structures we report address the decrease in rate of formation of ternary complexes in the E60 mutants. Structures of ternary complexes of L.casei TS mimic ligand-bound TS just prior to covalent bond formation between ligands and protein. Ternary complex structures of L.casei TS E60Q show the ligands are not optimally aligned for making the necessary covalent bonds. Since CB3717 is an analog of the open, activated form of the cofactor, these structures suggest that the slow rate of ternary complex formation in E60 mutants is at least partly the result of impaired alignment of ligands in the active site after binding and activation of the cofactor. Binary complexes of TS E60Q and TS E60D with substrate (dUMP) show no change in dUMP position or occupancy. These results are consistent with the fact that Kd(dUMP) and Km(dUMP) are almost the same, and the rates of folate-independent debromination of 5-bromo-dUMP are even higher than for wild type TS.      

Development of a fuel element with low harmful neutron absorption for the SM high-flux research reactor

Information about the SM research reactor and its characteristic features and advantages over other research reactors is presented. The reasons for updating the reactor and the optimal method of solving the problem are indicated. The upgrade program preserves the essential structural features of the rector and allows for the insertion of additional irradiation channels in the fuel part of the core by removing some fuel elements. The reactivity loss arising in so doing is compensated by increasing the uranium content in the remaining fuel elements. A new type of fuel element based on materials with reduced harmful absorption of neutrons is being developed to improve further the technical and economic performance of the reactor. The design and the technology of the fuel element have been developed for three implementations, and experimental fuel elements for reactor tests have been fabricated. The fuel elements have been checked for adherence to the requirements. It has been shown that normal operation of the fuel elements is possible with heat flux density at the surface 9–12 MW/m², which meets the initial requirements.     

Conceptions and misconceptions about transmission of HIV/AIDS among the Scottish general public, 1988-1992

Knowledge levels among the Scottish general public about so called 'casual' transmission of the AIDS virus were analysed using data collected by our Unit's survey using computer-assisted telephone interviewing methods. Five cross-sections of data from the period March to May of each year were analysed and compared to provide overall estimates of knowledge on four items relating to casual transmission between respondent groups and to provide an estimate of changes over time in knowledge levels from 1988 to 1992. The data show that significant differences in knowledge exist, with the lowest levels of knowledge found among the older and among the less educated respondents. There is evidence for a continuing increase in knowledge for all items studied and for most respondent groups, but little evidence that disparities in knowledge between respondent groups are lessening over time. Misconceptions about potential risks from donating blood and kissing persist at quite high levels.