Accelerator measurement of the energy spectra of neutrons emitted in the interaction of 3-GeV protons with several elements

The application of time of flight techniques for determining the shapes of the energy spectra of neutrons between 20 and 400 MeV is discussed. The neutrons are emitted at 20, 34, and 90 degrees in the bombardment of targets by 3 GeV protons. The targets used are carbon, aluminum, cobalt, and platinum with cylindrical cross section. Targets being bombarded are located in the internal circulating beam of a particle accelerator

Preferential utilization of NADPH as the endogenous electron donor for NAD(P)H:quinone oxidoreductase 1 (NQO1) in intact pulmonary arterial endothelial cells

The goal was to determine whether endogenous cytosolic NAD(P)H:quinone oxidoreductase 1 (NQO1) preferentially uses NADPH or NADH in intact pulmonary arterial endothelial cells in culture. The approach was to manipulate the redox status of the NADH/NAD+ and NADPH/NADP+ redox pairs in the cytosolic compartment using treatment conditions targeting glycolysis and the pentose phosphate pathway alone or with lactate, and to evaluate the impact on the intact cell NQO1 activity. Cells were treated with 2-deoxyglucose, iodoacetate, or epiandrosterone in the absence or presence of lactate, NQO1 activity was measured in intact cells using duroquinone as the electron acceptor, and pyridine nucleotide redox status was measured in total cell KOH extracts by high-performance liquid chromatography. 2-Deoxyglucose decreased NADH/NAD+ and NADPH/NADP+ ratios by 59 and 50%, respectively, and intact cell NQO1 activity by 74%; lactate restored NADH/NAD+, but not NADPH/NADP+ or NQO1 activity. Iodoacetate decreased NADH/NAD+ but had no detectable effect on NADPH/NADP+ or NQO1 activity. Epiandrosterone decreased NQO1 activity by 67%, and although epiandrosterone alone did not alter the NADPH/NADP+ or NADH/NAD+ ratio, when the NQO1 electron acceptor duroquinone was also present, NADPH/NADP+ decreased by 84% with no impact on NADH/NAD+. Duroquinone alone also decreased NADPH/NADP+ but not NADH/NAD+. The results suggest that NQO1 activity is more tightly coupled to the redox status of the NADPH/NADP+ than NADH/NAD+ redox pair, and that NADPH is the endogenous NQO1 electron donor. Parallel studies of pulmonary endothelial transplasma membrane electron transport (TPMET), another redox process that draws reducing equivalents from the cytosol, confirmed previous observations of a correlation with the NADH/NAD+ ratio

Characterization of theThreshold for NAD(P)H:quinone Oxidoreductase Activity in Intact Sulforaphane-treated Pulmonary Arterial Endothelial Cells

Treatment of bovine pulmonary arterial endothelial cells in culture with the phase II enzyme inducer sulforaphane (5 μM, 24 h; sulf-treated) increased cell-lysate NAD(P)H:quinone oxidoreductase (NQO1) activity by 5.7 ± 0.6 (mean ± SEM)-fold, but intact-cell NQO1 activity by only 2.8 ± 0.1-fold compared to control cells. To evaluate the hypothesis that the threshold for sulforaphane-induced intact-cell NQO1 activity reflects a limitation in the capacity to supply NADPH at a sufficient rate to drive all the induced NQO1 to its maximum activity, total KOH-extractable pyridine nucleotides were measured in cells treated with duroquinone to stimulate maximal NQO1 activity. NQO1 activation increased NADP+ in control and sulf-treated cells, with the effect more pronounced in the sulf-treated cells, in which the NADPH was also decreased. Glucose-6-phosphate dehydrogenase (G-6-PDH) inhibition partially blocked NQO1 activity in control and sulf-treated cells, but G-6-PDH overexpression via transient transfection with the human cDNA alleviated neither the restriction on intact sulf-treated cell NQO1 activity nor the impact on the NADPH/NADP+ ratios. Intracellular ATP levels were not affected by NQO1 activation in control or sulf-treated cells. An increased dependence on extracellular glucose and a rightward shift in the Km for extracellular glucose were observed in NQO1-stimulated sulf-treated vs control cells. The data suggest that glucose transport in the sulf-treated cells may be insufficient to support the increased metabolic demand for pentose phosphate pathway-generated NADPH as an explanation for the NQO1 threshold

Atmospheric neutrons

Contributions to fast neutron measurements in the atmosphere are outlined. The results of a calculation to determine the production, distribution and final disappearance of atmospheric neutrons over the entire spectrum are presented. An attempt is made to answer questions that relate to processes such as neutron escape from the atmosphere and C-14 production. In addition, since variations of secondary neutrons can be related to variations in the primary radiation, comment on the modulation of both radiation components is made

Effective algebraic degeneracy

We prove that any nonconstant entire holomorphic curve from the complex line C into a projective algebraic hypersurface X = X^n in P^{n+1}(C) of arbitrary dimension n (at least 2) must be algebraically degenerate provided X is generic if its degree d = deg(X) satisfies the effective lower bound: d larger than or equal to n^{{(n+1)}^{n+5}}

К разработке технологии возведения геокомпозитных охранных систем горных выработок

У статті розглянуто відмінності використання особливо тонко дисперсних в’яжучих (ОТДВ) у підземних умовах для створення елементів геокомпозитних конструкцій.In article the differences of the use especially thinly of dispersible astringent are considered in underground terms for creation elements of geocomposit constructions

Using an OPEN UMS format for document flow formalization in medicine

The question about construction of medical documents by means of AURRORA MIS with the use of the Open UMS format is considered in the work. The approach suggested allows data storage in the electronic form suitable for generation of required statistical reports and different researches and preserves a possibility of correct data interpretation

Intracellular uptake of macromolecules by brain lymphatic endothelial cells during zebrafish embryonic development

The lymphatic system controls fluid homeostasis and the clearance of macromolecules from interstitial compartments. In mammals brain lymphatics were only recently discovered, with significant implications for physiology and disease. We examined zebrafish for the presence of brain lymphatics and found loosely connected endothelial cells with lymphatic molecular signature covering parts of the brain without forming endothelial tubular structures. These brain lymphatic endothelial cells (BLECs) derive from venous endothelium, are distinct from macrophages, and are sensitive to loss of Vegfc. BLECs endocytose macromolecules in a selective manner, which can be blocked by injection of mannose receptor ligands. This first report on brain lymphatic endothelial cells in a vertebrate embryo identifies cells with unique features, including the uptake of macromolecules at a single cell level. Future studies will address whether this represents an uptake mechanism that is conserved in mammals and how these cells affect functions of the embryonic and adult brain