836 research outputs found

    Phenotypic and genotypic monitoring of Schistosoma mansoni in Tanzanian schoolchildren five years into a preventative chemotherapy national control programme

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    We conducted combined in vitro PZQ efficacy testing with population genetic analyses of S. mansoni collected from children from two schools in 2010, five years after the introduction of a National Control Programme. Children at one school had received four annual PZQ treatments and the other school had received two mass treatments in total. We compared genetic differentiation, indices of genetic diversity, and estimated adult worm burden from parasites collected in 2010 with samples collected in 2005 (before the control programme began) and in 2006 (six months after the first PZQ treatment). Using 2010 larval samples, we also compared the genetic similarity of those with high and low in vitro sensitivity to PZQ

    Effect of thermal treatments on the structure of MoNxOy thin films

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    Article in PressMoNxOy films were deposited on steel substrates by dc reactive magnetron sputtering. The depositions were carried out from a pure molybdenum target, varying the flow rate of reactive gases. X-ray diffraction (XRD) results revealed the occurrence of cubic MoNx and hexagonal (d-MoN) phases for the films with high nitrogen flow rates. The increase of oxygen content induces the decrease of the grain size of the molybdenum nitride crystallites. The thermal stability of a set of samples was studied in vacuum, for an annealing time of 1 h, for temperatures ranging from 500 to 800 C in 100 C steps. The results showed that pure molybdenum nitride films changed their structure from a meta-stable cubic MoN to hexagonal d-MoN and cubic g-Mo2N-type structures with increasing annealing temperatures. The samples with molybdenum nitride films evidenced a good thermal stability, but those with molybdenum oxynitride coatings showed a tendency to detach with the increase of the annealing temperature.Fundação para a CiĂȘncia e a Tecnologia (FCT) - POCTI/CTM/38086/200

    Properties of MoNxOy thin films as a function of N/O ratio

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    The main purpose of this work consists on the preparation of single layered molybdenum oxynitride, MoNxOy. The films were deposited on steel substrates by dc reactive magnetron sputtering. The depositions were carried out from a pure Mo target varying the flow rate of reactive gases, which allowed tune the crystallographic structure between insulating oxides and metallic nitrides and consequently electronic, mechanical and optical properties of the material. X-ray diffraction (XRD) results revealed the occurrence of molybdenum nitride for the films with low oxygen fraction: face-centred cubic phases (gama-Mo2N) for low nitrogen flow rate or cubic MoNx and hexagonal phase (delta-MoN) for high nitrogen flow rate. The increase of oxygen content induces an amorphization of the nitride phases and appearance of MoO3 phases. The increase of the oxygen fraction in the films induces also a high decrease in films hardness. Residual stresses revealed to be of compressive type, in the range of very few tenths of GPa to 2 GPa. All these results have been analysed and will be presented as a function of the deposition parameters, the chemical composition and the structure of the films.Fundação para a CiĂȘncia e a Tecnologia (FCT) – Pograma Operacional “CiĂȘncia, Tecnologia, Inovação” - POCTI/CTM/38086/2001.Comunidade Europeia (CE). Fundo Europeu de Desenvolvimento Regional (FEDER)

    Observation of two new Ξb−\Xi_b^- baryon resonances

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    Two structures are observed close to the kinematic threshold in the Ξb0π−\Xi_b^0 \pi^- mass spectrum in a sample of proton-proton collision data, corresponding to an integrated luminosity of 3.0 fb−1^{-1} recorded by the LHCb experiment. In the quark model, two baryonic resonances with quark content bdsbds are expected in this mass region: the spin-parity JP=12+J^P = \frac{1}{2}^+ and JP=32+J^P=\frac{3}{2}^+ states, denoted Ξbâ€Č−\Xi_b^{\prime -} and Ξb∗−\Xi_b^{*-}. Interpreting the structures as these resonances, we measure the mass differences and the width of the heavier state to be m(Ξbâ€Č−)−m(Ξb0)−m(π−)=3.653±0.018±0.006m(\Xi_b^{\prime -}) - m(\Xi_b^0) - m(\pi^{-}) = 3.653 \pm 0.018 \pm 0.006 MeV/c2/c^2, m(Ξb∗−)−m(Ξb0)−m(π−)=23.96±0.12±0.06m(\Xi_b^{*-}) - m(\Xi_b^0) - m(\pi^{-}) = 23.96 \pm 0.12 \pm 0.06 MeV/c2/c^2, Γ(Ξb∗−)=1.65±0.31±0.10\Gamma(\Xi_b^{*-}) = 1.65 \pm 0.31 \pm 0.10 MeV, where the first and second uncertainties are statistical and systematic, respectively. The width of the lighter state is consistent with zero, and we place an upper limit of Γ(Ξbâ€Č−)<0.08\Gamma(\Xi_b^{\prime -}) < 0.08 MeV at 95% confidence level. Relative production rates of these states are also reported.Comment: 17 pages, 2 figure

    A new human chromogranin A (CgA) immunoradiometric assay involving monoclonal antibodies raised against the unprocessed central domain (145-245)

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    Chromogranin A (CgA), a major protein of chromaffin granules, has been described as a potential marker for neuroendocrine tumours. Because of an extensive proteolysis which leads to a large heterogeneity of circulating fragments, its presence in blood has been assessed in most cases either by competitive immunoassays or with polyclonal antibodies. In the present study, 24 monoclonal antibodies were raised against native or recombinant human CgA. Their mapping with proteolytic peptides showed that they defined eight distinct epitopic groups which spanned two-thirds of the C-terminal part of human CgA. All monoclonal antibodies were tested by pair and compared with a reference radioimmunoassay (RIA) involving CGS06, one of the monoclonal antibodies against the 198–245 sequence. It appears that CgA C-terminal end seems to be highly affected by proteolysis and the association of C-terminal and median-part monoclonal antibodies is inadequate for total CgA assessment. Our new immunoradiometric assay involves two monoclonal antibodies, whose contiguous epitopes lie within the median 145–245 sequence. This assay allows a sensitive detection of total human CgA and correlates well with RIA because dibasic cleavage sites present in the central domain do not seem to be affected by degradation. It has been proved to be efficient in measuring CgA levels in patients with neuroendocrine tumours. © 1999 Cancer Research Campaig

    First observation and amplitude analysis of the B−→D+K−π−B^{-}\to D^{+}K^{-}\pi^{-} decay

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    The B−→D+K−π−B^{-}\to D^{+}K^{-}\pi^{-} decay is observed in a data sample corresponding to 3.0 fb−13.0~\rm{fb}^{-1} of pppp collision data recorded by the LHCb experiment during 2011 and 2012. Its branching fraction is measured to be B(B−→D+K−π−)=(7.31±0.19±0.22±0.39)×10−5{\cal B}(B^{-}\to D^{+}K^{-}\pi^{-}) = (7.31 \pm 0.19 \pm 0.22 \pm 0.39) \times 10^{-5} where the uncertainties are statistical, systematic and from the branching fraction of the normalisation channel B−→D+π−π−B^{-}\to D^{+}\pi^{-}\pi^{-}, respectively. An amplitude analysis of the resonant structure of the B−→D+K−π−B^{-}\to D^{+}K^{-}\pi^{-} decay is used to measure the contributions from quasi-two-body B−→D0∗(2400)0K−B^{-}\to D_{0}^{*}(2400)^{0}K^{-}, B−→D2∗(2460)0K−B^{-}\to D_{2}^{*}(2460)^{0}K^{-}, and B−→DJ∗(2760)0K−B^{-}\to D_{J}^{*}(2760)^{0}K^{-} decays, as well as from nonresonant sources. The DJ∗(2760)0D_{J}^{*}(2760)^{0} resonance is determined to have spin~1.Comment: 39 pages, 10 figures, submitted to Phys. Rev. D. Updated following erratum 10.1103/PhysRevD.93.11990

    Differential branching fraction and angular analysis of Λb0→ΛΌ+Ό−\Lambda^{0}_{b} \rightarrow \Lambda \mu^+\mu^- decays

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    The differential branching fraction of the rare decay Λb0→ΛΌ+Ό−\Lambda^{0}_{b} \rightarrow \Lambda \mu^+\mu^- is measured as a function of q2q^{2}, the square of the dimuon invariant mass. The analysis is performed using proton-proton collision data, corresponding to an integrated luminosity of 3.0 \mbox{ fb}^{-1}, collected by the LHCb experiment. Evidence of signal is observed in the q2q^2 region below the square of the J/ψJ/\psi mass. Integrating over 15 < q^{2} < 20 \mbox{ GeV}^2/c^4 the branching fraction is measured as d\mathcal{B}(\Lambda^{0}_{b} \rightarrow \Lambda \mu^+\mu^-)/dq^2 = (1.18 ^{+ 0.09} _{-0.08} \pm 0.03 \pm 0.27) \times 10^{-7} ( \mbox{GeV}^{2}/c^{4})^{-1}, where the uncertainties are statistical, systematic and due to the normalisation mode, Λb0→J/ψΛ\Lambda^{0}_{b} \rightarrow J/\psi \Lambda, respectively. In the q2q^2 intervals where the signal is observed, angular distributions are studied and the forward-backward asymmetries in the dimuon (AFBlA^{l}_{\rm FB}) and hadron (AFBhA^{h}_{\rm FB}) systems are measured for the first time. In the range 15 < q^2 < 20 \mbox{ GeV}^2/c^4 they are found to be A^{l}_{\rm FB} = -0.05 \pm 0.09 \mbox{ (stat)} \pm 0.03 \mbox{ (syst)} and A^{h}_{\rm FB} = -0.29 \pm 0.07 \mbox{ (stat)} \pm 0.03 \mbox{ (syst)}.Comment: 27 pages, 10 figures, Erratum adde
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