411 research outputs found

    Cytotoxic effects on splenic ultrafiltrates upon leukaemic lymphocytes.

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    Ultrafiltrates from spleen inhibited both DNA synthesis and the proliferation of normal lymphocytes stimulated inculture from both mouse and man without apparent cytotoxicity. However, the same doses of this spleen ultrafiltrate will kill up to two-thirds of the leukaemic lymphoblasts from both mouse and man after 24 h incubation. This unique lymphocytotoxic effect could also be demonstrated on fresh primary cultures of leukaemic lymphocytes and was highly effective on slowly growing established cell lines under crowd culture conditions. Furthermore. ultrafiltrated thymus extract did not affect the DNA synthesis rates of the viability of NC-37 lymphoblasts, which have B cell characteristic. Thymus extract was cytotoxic to Molt cells, which have T cell characteristics

    Insulin sensitizing agent improves clinical pregnancy rate and insulin resistant parameters in polycystic ovarian syndrome patients with acanthosis nigricans: a randomized controlled study

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    Objective: To investigate the effect of adding metformin to clomiphene citrate (CC) in polycystic ovarian syndrome (PCOS) patients with acanthosis nigricans (AN) who were previously not responding to CC. Material and Methods: A double blinded randomized controlled trial (NCT02562664) included 66 PCOS women with acanthosis nigricans who were CC resistant (at least 3 months). Day 3 follicle stimulating hormone (FSH) level, fasting insulin, fasting glucose and homeostatic model assessment were used to quantify insulin resistance. Participants were randomly assigned to either group I (CC with placebo tablets) or group II (CC with metformin) for three cycles. Insulin resistance parameters as well as clinical pregnancy rate had been evaluated in both groups. The statistical analysis was done using Chi- square and Fischer exact tests. Results: The demographic data was comparable in both groups, however; there was higher cumulative pregnancy rate after three cycles of stimulation in group II (18/33) (54.5%) in comparison with group I (7/33) (21.1%) (P=0.03). There was a significant improvement in the insulin resistance parameters after three months of combining clomiphene citrate with metformin as compared with CC alone. Conclusion: Adding metformin to CC in clomiphene citrate resistant PCOS patients who have acanthosis nigricans improves the pregnancy rate and insulin resistant parameters

    Diffractive Contribution to the Elasticity and the Nucleonic Flux in the Atmosphere

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    We calculate the average elasticity considering non-diffractive and single diffractive interactions and perform an analysis of the cosmic-ray flux by means of an analytical solution for the nucleonic diffusion equation. We show that the diffractive contribution is important for the adequate description of the nucleonic and hadronic fluxes in the atmosphere.Comment: 10 pages, latex, 2 figures (uuencoded PostScript

    Effect of grain size reduction of AA2124 aluminum alloy powder compacted by spark plasma sintering

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    AbstractNanocrystalline (Average grain size ∼200nm) bulk AA2124 alloy was produced through high energy ball milling of microcrystalline powder followed by spark plasma sintering (SPS) at 480°C with a holding time of 10min. The effect of initial particle and grain size on the microstructural evolution as well as on the relative density and mechanical properties of the specimens consolidated through SPS and hot pressing (HP) at the same temperature for 60min was investigated for ball milled nano-powders (NP), as well as as-received micro-powders (MP). Results showed that the NP specimens consolidated with SPS had the highest microhardness values compared to the other specimens despite not achieving full densification. On the other hand, a general increase in density, hardness, and compressive strength was observed for all SPS consolidates compared to HP. The presence of aluminum oxide and its influence on the consolidation process as well as the resulting mechanical properties of the bulk specimens is also discussed

    High energy hadrons in EAS at mountain altitude

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    An extensive simulation has been carried out to estimate the physical interpretation of dynamical factors such as , in terms of high energy interaction features, concentrated in the present analysis on the average transverse momentum. It appears that the large enhancement observed for versus primary energy, suggesting in earliest analysis a significant rise of with energy, is only the result of the limited resolution of the detectors and remains in agreement with a wide range of models used in simulations.Comment: 13 pages, 6 PostScript figures, LaTeX Subm. to JPhys

    Laser powder bed fusion at sub-atmospheric pressures

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    The perceived advantages of laser powder bed fusion (PBF) at reduced pressure include a more stable melt pool and reduced porosity. In this study, high-speed imaging was used to investigate the interaction of the laser beam with the powder bed at sub-atmospheric pressures. At atmospheric pressure, the laser plume produces a flow in the ambient atmosphere that entrains particles toward the melt pool. As the pressure decreases, this hydrodynamic entrainment increases but eventually the expansion of the laser plume prevents the particles reaching the melt pool: profiles and cross-sections of the track reveal a drastic reduction in its cross-sectional area. As the pressure decreases further, into the molecular flow regime, particles are only repelled by the plume away from the melt pool. The regime between 1 bar and ∼50 mbar (the threshold pressure at which the penetration depth no longer increases) could provide a window for successful processing but might require a pre-sinter to maintain the integrity of the powder bed. Lower pressures would definitely require a pre-sinter, for which the additional processing time and increase in process complexity might be justified for porosity-critical applications
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