464 research outputs found

    Effect of lysolecithin on the oxygen uptake of tumour cells, polymorphonuclear leucocytes, lymphocytes and macrophages in vitro.

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    LYSOLECITHN has been widely studied as a surface-active haemolytic agent (Robinson, 1961) and has been implicated in immune haemolysis (Fischer, 1964), in hypersensitivity reactions (Middleton and Phillips, 1963, 1964), and in the delayed stage of the increase of vascular permeability in inflammation (Cotran and Majno, 1964). Fischer (1964) found that the oxygen uptake (Q02) of tumour cells was reduced by small concentrations of "lysolecithin ", while micro and macrophages responded by an increase Of Q02 and phagocytic activity. We felt that this observation should be confirmed, because it could form the basis of a therapeutic method of increasing the radiosensitivity of tumours by raising the oxygen tension (PO2), and from the theoretical aspect might clarify differences between the cell membranes of tumour and of normal cells. Moreover, Fischer's experiments are open to criticism. His cell suspension was stirred by a moving mercury seal and this could have produced cell damage from mercury poisoning. Also he treated his cell suspensions not with lysolecithin, but with complement plus a specific antibod

    Techniques for improving reliability of computers

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    Modular design techniques improve methods of error detection, diagnosis, and recovery. Theoretical computer (MARCS (Modular Architecture for Reliable Computer Systems)) study deals with postulated and modeled technology indigenous to 1975-1980. Study developments are discussed

    Interpretation and reporting of process capability results: focus on improvement

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    A global financial services company followed a software-mediated process assessment (SMPA) approach based on ISO/IEC 15504, ISO/IEC 20000 and the IT Infrastructure Library (ITIL®). Using an action research approach, the Incident Management, Problem Management, and Change Management processes were assessed at two points in time during an ITSM process improvement project. This paper analyzes the results of the process assessments, highlights issues with the interpretation of the results, and offers an alternative method to report process capability results to motivate process improvement. The study found that by using the proportion of SMPA recommendations as a proxy measure for process improvement, the processes did improve yielding fewer recommendations in cycle 2 when compared to cycle 1 of the action research

    Charged Vortices in High Temperature Superconductors Probed by NMR

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    We report a first experimental evidence that a vortex in the high temperature superconductors (HTSC) traps a finite electric charge from the high resolution measurements of the nuclear quadrupole frequencies. In slightly overdoped YBa_2Cu_3O_7 the vortex is negatively charged by trapping electrons, while in underdoped YBa_2Cu_4O_8 it is positively charged by expelling electrons. The sign of the trapped charge is opposite to the sign predicted by the conventional BCS theory. Moreover, in both materials, the deviation of the magnitude of the charge from the theory is also significant. These unexpected features can be attributed to the novel electronic structure of the vortex in HTSC.Comment: 6 pages, 7 figures, to be published in Phys Rev.

    Copper as a target for prostate cancer therapeutics: copper-ionophore pharmacology and altering systemic copper distribution

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    Copper-ionophores that elevate intracellular bioavailable copper display significant therapeutic utility against prostate cancer cells in vitro and in TRAMP (Transgenic Adenocarcinoma of Mouse Prostate) mice. However, the pharmacological basis for their anticancer activity remains unclear, despite impending clinical trails. Herein we show that intracellular copper levels in prostate cancer, evaluated in vitro and across disease progression in TRAMP mice, were not correlative with copper-ionophore activity and mirrored the normal levels observed in patient prostatectomy tissues (Gleason Score 7 & 9). TRAMP adenocarcinoma cells harbored markedly elevated oxidative stress and diminished glutathione (GSH)-mediated antioxidant capacity, which together conferred selective sensitivity to prooxidant ionophoric copper. Copper-ionophore treatments [CuII(gtsm), disulfiram & clioquinol] generated toxic levels of reactive oxygen species (ROS) in TRAMP adenocarcinoma cells, but not in normal mouse prostate epithelial cells (PrECs). Our results provide a basis for the pharmacological activity of copper-ionophores and suggest they are amendable for treatment of patients with prostate cancer. Additionally, recent in vitro and mouse xenograft studies have suggested an increased copper requirement by prostate cancer cells. We demonstrated that prostate adenocarcinoma development in TRAMP mice requires a functional supply of copper and is significantly impeded by altered systemic copper distribution. The presence of a mutant copper-transporting Atp7b protein (tx mutation: A4066G/Met1356Val) in TRAMP mice changed copper-integration into serum and caused a remarkable reduction in prostate cancer burden (64% reduction) and disease severity (grade), abrogating adenocarcinoma development. Implications for current clinical trials are discussed

    Virtual Shaping on NACA 0015 by Means of a High Momentum Coefficient Synthetic Jet

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    Results concerning flow control on a NACA 0015 airfoil using high power synthetic jets are presented for low incidences and for Reynolds numbers ranging from 132000 to 425000. The forcing was operated through a spanwise slit positioned near the leading edge at x/c=1.25% or at x/c=10% on the upper surface. Static pressure distribution measurements around the airfoil, wake surveys and smoke flow visualizations were performed. Pressure distributions were significantly modified around the injection location, showing an area of intense suction which increased the lift and strongly affected the drag. Flow visualizations highlighted that the intense suction was due to a virtual shaping effect caused by the formation of a recirculation bubble capable of displacing the streamlines. Low momentum deficits in the wake velocity distributions and, in certain conditions, jet-like flow was observed for the forced cases. Finally, a scaling law relating the bubble size to the forcing intensity is propose

    Hairs on the cosmological horizon

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    We investigate the possibility of having hairs on the cosmological horizon. The cosmological horizon shares similar properties of black hole horizons in the aspect of having hairs on the horizons. For those theories admitting haired black hole solutions, the nontrivial matter fields may reach and extend beyond the cosmological horizon. For Q-stars and boson stars, the matter fields cannot reach the cosmological horizon. The no short hair conjecture keeps valid, despite the asymptotic behavior (de Sitter or anti-de Sitter) of black hole solutions. We prove the no scalar hair theorem for anti-de Sitter black holes. Using the Bekenstein's identity method, we also prove the no scalar hair theorem for the de Sitter space and de Sitter black holes if the scalar potential is convex.Comment: Revtex, no figures, 16 page

    Enzyme‐assisted aqueous extraction of Kalahari melon seed oil: optimization using response surface methodology

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    Enzymatic extraction of oil from Kalahari melon seeds was investigated and evaluated by response surface methodology (RSM). Two commercial protease enzyme products were used separately: Neutrase® 0.8 L and Flavourzyme® 1000 L from Novozymes (Bagsvaerd, Denmark). RSM was applied to model and optimize the reaction conditions namely concentration of enzyme (20–50 g kg−1 of seed mass), initial pH of mixture (pH 5–9), incubation temperature (40–60 °C), and incubation time (12–36 h). Well fitting models were successfully established for both enzymes: Neutrase 0.8 L (R 2 = 0.9410) and Flavourzyme 1000 L (R 2 = 0.9574) through multiple linear regressions with backward elimination. Incubation time was the most significant reaction factor on oil yield for both enzymes. The optimal conditions for Neutrase 0.8 L were: an enzyme concentration of 25 g kg−1, an initial pH of 7, a temperature at 58 °C and an incubation time of 31 h with constant shaking at 100 rpm. Centrifuging the mixture at 8,000g for 20 min separated the oil with a recovery of 68.58 ± 3.39%. The optimal conditions for Flavourzyme 1000 L were enzyme concentration of 21 g kg−1, initial pH of 6, temperature at 50 °C and incubation time of 36 h. These optimum conditions yielded a 71.55 ± 1.28% oil recovery
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