939 research outputs found

    How specific is the immune response to malaria in adults living in endemic areas?

    Get PDF
    It is documented that people living in malaria endemic areas acquire immunity against malaria afterrepeated infections. Studies involving passive transfer of IgG from immune adults to the nonimmunesubjects have shown that circulating antibodies play an important role, and that immuneadults possess protective antibodies, which susceptible malaria patients do not. Through a differentialimmunoscreen, we have identified several novel cDNA clones, which react exclusively andyet extensively with immune sera samples. Specific antisera raised against the immunoclones inhibitthe growth of parasites in culture. The clones studied so far turn out to be novel conserved Plasmodiumgenes. In order to study the response of sera of adults from malaria endemic areas of Indiaand Africa to these immunogens, we carried out ELISA assays using these immunopeptides, otherP. falciparum specific antigens, peptides, antigens from other infections such as mycobacterial infectionsand other proteins such as BSA. Children from the same areas and normal healthy urbanpeople showed very little activity to each of these categories. A large percentage of adults from endemicareas responded positively to all the malarial immunogens tested. However, the same personsalso showed high response to other antigens and proteins as well. The implications of theseresults are reported in this paper

    Elicitation of diosgenin production in Trigonella foenum-graecum (fenugreek) seedlings by methyl jasmonate

    Get PDF
    The effects of methyl jasmonate (MeJA), an elicitor of plant defense mechanisms, on the biosynthesis of diosgenin, a steroidal saponin, were investigated in six fenugreek (Trigonella foenum-graecum) varieties (Gujarat Methi-2, Kasuri-1, Kasuri-2, Pusa Early Branching, Rajasthan Methi and Maharashtra Methi-5). Treatment with 0.01% MeJA increased diosgenin levels, in 12 days old seedlings, from 0.5%-0.9% to 1.1%-1.8%. In addition, MeJA upregulated the expression of two pivotal genes of the mevalonate pathway, the metabolic route leading to diosgenin: 3-hydroxy-3-methylglutaryl-CoA reductase (HMG) and sterol-3-\u3b2-glucosyl transferase (STRL). In particular, MeJA increased the expression of HMG and STRL genes by 3.2- and 22.2-fold, respectively, in the Gujarat Methi-2 variety, and by 25.4- and 28.4-fold, respectively, in the Kasuri-2 variety. Therefore, MeJA may be considered a promising elicitor for diosgenin production by fenugreek plants

    A first estimate of triply heavy baryon masses from the pNRQCD perturbative static potential

    Get PDF
    Within pNRQCD we compute the masses of spin-averaged triply heavy baryons using the now-available NNLO pNRQCD potentials and three-body variational approach. We focus in particular on the role of the purely three-body interaction in perturbation theory. This we find to be reasonably small and of the order 25 MeV Our prediction for the Omega_ccc baryon mass is 4900(250) in keeping with other approaches. We propose to search for this hitherto unobserved state at B factories by examining the end point of the recoil spectrum against triple charm.Comment: 18 figures, 21 page

    Six Years of Chandra Observations of Supernova Remnants

    Full text link
    We present a review of the first six years of Chandra X-ray Observatory observations of supernova remnants. From the official "first-light" observation of Cassiopeia A that revealed for the first time the compact remnant of the explosion, to the recent million-second spectrally-resolved observation that revealed new details of the stellar composition and dynamics of the original explosion, Chandra observations have provided new insights into the supernova phenomenon. We present an admittedly biased overview of six years of these observations, highlighting new discoveries made possible by Chandra's unique capabilities.Comment: 82 pages, 28 figures, for the book Astrophysics Update

    Search for lepton-flavor violation at HERA

    Get PDF
    A search for lepton-flavor-violating interactions ep→μXe p \to \mu X and ep→τXe p\to \tau X has been performed with the ZEUS detector using the entire HERA I data sample, corresponding to an integrated luminosity of 130 pb^{-1}. The data were taken at center-of-mass energies, s\sqrt{s}, of 300 and 318 GeV. No evidence of lepton-flavor violation was found, and constraints were derived on leptoquarks (LQs) that could mediate such interactions. For LQ masses below s\sqrt{s}, limits were set on λeq1βℓq\lambda_{eq_1} \sqrt{\beta_{\ell q}}, where λeq1\lambda_{eq_1} is the coupling of the LQ to an electron and a first-generation quark q1q_1, and βℓq\beta_{\ell q} is the branching ratio of the LQ to the final-state lepton ℓ\ell (μ\mu or τ\tau) and a quark qq. For LQ masses much larger than s\sqrt{s}, limits were set on the four-fermion interaction term λeqαλℓqβ/MLQ2\lambda_{e q_\alpha} \lambda_{\ell q_\beta} / M_{\mathrm{LQ}}^2 for LQs that couple to an electron and a quark qαq_\alpha and to a lepton ℓ\ell and a quark qβq_\beta, where α\alpha and β\beta are quark generation indices. Some of the limits are also applicable to lepton-flavor-violating processes mediated by squarks in RR-Parity-violating supersymmetric models. In some cases, especially when a higher-generation quark is involved and for the process ep→τXe p\to \tau X , the ZEUS limits are the most stringent to date.Comment: 37 pages, 10 figures, Accepted by EPJC. References and 1 figure (Fig. 6) adde
    • …
    corecore