399 research outputs found

    Surface-initiated growth of copper using isonicotinic acid-functionalized aluminum oxide surfaces

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    Isonicotinate self-assembled monolayers (SAM) were prepared on alumina surfaces (A) using isonicotinic acid (iNA). These functionalized layers (iNA-A) were used for the seeded growth of copper films (Cu-iNA-A) by hydrazine hydrate-initiated electroless deposition. The films were characterized by scanning electron microscopy (SEM), electron-dispersive X-ray spectroscopy, atomic force microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and advancing contact angle measurements. The films are Cu0 but with surface oxidation, and show a faceted morphology, which is more textured (Rq = 460 ± 90 nm) compared to the SAM (Rq = 2.8 ± 0.5 nm). In contrast, growth of copper films by SnCl2/PdCl2 catalyzed electroless deposition, using formaldehyde (CH2O) as the reducing agent, shows a nodular morphology on top of a relatively smooth surface. No copper films are observed in the absence of the isonicotinate SAM. The binding of Cu2+ to the iNA is proposed to facilitate reduction to Cu0 and create the seed for subsequent growth. The films show good adhesion to the functionalized surface

    The role of the RACK1 ortholog Cpc2p in modulating pheromone-induced cell cycle arrest in fission yeast

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    The detection and amplification of extracellular signals requires the involvement of multiple protein components. In mammalian cells the receptor of activated C kinase (RACK1) is an important scaffolding protein for signal transduction networks. Further, it also performs a critical function in regulating the cell cycle by modulating the G1/S transition. Many eukaryotic cells express RACK1 orthologs, with one example being Cpc2p in the fission yeast Schizosaccharomyces pombe. In contrast to RACK1, Cpc2p has been described to positively regulate, at the ribosomal level, cells entry into M phase. In addition, Cpc2p controls the stress response pathways through an interaction with Msa2p, and sexual development by modulating Ran1p/Pat1p. Here we describe investigations into the role, which Cpc2p performs in controlling the G protein-mediated mating response pathway. Despite structural similarity to Gβ-like subunits, Cpc2p appears not to function at the G protein level. However, upon pheromone stimulation, cells overexpressing Cpc2p display substantial cell morphology defects, disorientation of septum formation and a significantly protracted G1 arrest. Cpc2p has the potential to function at multiple positions within the pheromone response pathway. We provide a mechanistic interpretation of this novel data by linking Cpc2p function, during the mating response, with its previous described interactions with Ran1p/Pat1p. We suggest that overexpressing Cpc2p prolongs the stimulated state of pheromone-induced cells by increasing ste11 gene expression. These data indicate that Cpc2p regulates the pheromone-induced cell cycle arrest in fission yeast by delaying cells entry into S phase

    Guillain-Barré syndrome: a century of progress

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    In 1916, Guillain, Barré and Strohl reported on two cases of acute flaccid paralysis with high cerebrospinal fluid protein levels and normal cell counts — novel findings that identified the disease we now know as Guillain–Barré syndrome (GBS). 100 years on, we have made great progress with the clinical and pathological characterization of GBS. Early clinicopathological and animal studies indicated that GBS was an immune-mediated demyelinating disorder, and that severe GBS could result in secondary axonal injury; the current treatments of plasma exchange and intravenous immunoglobulin, which were developed in the 1980s, are based on this premise. Subsequent work has, however, shown that primary axonal injury can be the underlying disease. The association of Campylobacter jejuni strains has led to confirmation that anti-ganglioside antibodies are pathogenic and that axonal GBS involves an antibody and complement-mediated disruption of nodes of Ranvier, neuromuscular junctions and other neuronal and glial membranes. Now, ongoing clinical trials of the complement inhibitor eculizumab are the first targeted immunotherapy in GBS

    Dimethyl sulfide production: what is the contribution of the coccolithophores?

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    Knowledge transfer in Tehran University of Medical Sciences: an academic example of a developing country

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    <p>Abstract</p> <p>Background</p> <p>In the past two decades, scientific publications in Iran have considerably increased their medical science content, and the number of articles published in ISI journals has doubled between 1997 and 2001. The aim of the present study was to determine how frequently knowledge transfer strategies were applied in Tehran University of Medical Sciences (TUMS). We were also interested in studying the determining factors leading to the type of strategy selected.</p> <p>Methodology</p> <p>All TUMS research projects that had received grants from inside and outside the university in 2004, and were completed by the end of 2006, were included in the study. In total, 301 projects were examined, and data on each of the projects were collected by the research team using a standardized questionnaire. The projects' principle investigators filled out a second questionnaire. In all, 208 questionnaires were collected.</p> <p>Results</p> <p>Researchers stated being more engaged in the passive strategies of knowledge transfer, especially those publishing in peer-reviewed journals. The mean score for the researchers' performance in passive and active strategies were 22% and 9% of the total score, respectively. Linear regression analysis showed that the passive strategy score decreased with the increase in the number of years working as a professional (p = 0.01) and personal interest as the only reason for choosing the research topic (p = 0.01). Regarding the active strategies of knowledge transfer, health system research studies significantly raised the score (p = 0.02) and 'executive responsibility' significantly lowered it (p = 0.03).</p> <p>Conclusion</p> <p>As a study carried out in a Middle Eastern developing country, we see that, like many other universities in the world, many academicians still do not give priority to active strategies of knowledge transfer. Therefore, if 'linking knowledge to action' is necessary, it may also be necessary to introduce considerable changes in academic procedures and encouragement policies (<it>e.g.</it>, employment and promotion criteria of academic members).</p

    Knowledge transfer in Tehran University of Medical Sciences: an academic example of a developing country

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    <p>Abstract</p> <p>Background</p> <p>In the past two decades, scientific publications in Iran have considerably increased their medical science content, and the number of articles published in ISI journals has doubled between 1997 and 2001. The aim of the present study was to determine how frequently knowledge transfer strategies were applied in Tehran University of Medical Sciences (TUMS). We were also interested in studying the determining factors leading to the type of strategy selected.</p> <p>Methodology</p> <p>All TUMS research projects that had received grants from inside and outside the university in 2004, and were completed by the end of 2006, were included in the study. In total, 301 projects were examined, and data on each of the projects were collected by the research team using a standardized questionnaire. The projects' principle investigators filled out a second questionnaire. In all, 208 questionnaires were collected.</p> <p>Results</p> <p>Researchers stated being more engaged in the passive strategies of knowledge transfer, especially those publishing in peer-reviewed journals. The mean score for the researchers' performance in passive and active strategies were 22% and 9% of the total score, respectively. Linear regression analysis showed that the passive strategy score decreased with the increase in the number of years working as a professional (p = 0.01) and personal interest as the only reason for choosing the research topic (p = 0.01). Regarding the active strategies of knowledge transfer, health system research studies significantly raised the score (p = 0.02) and 'executive responsibility' significantly lowered it (p = 0.03).</p> <p>Conclusion</p> <p>As a study carried out in a Middle Eastern developing country, we see that, like many other universities in the world, many academicians still do not give priority to active strategies of knowledge transfer. Therefore, if 'linking knowledge to action' is necessary, it may also be necessary to introduce considerable changes in academic procedures and encouragement policies (<it>e.g.</it>, employment and promotion criteria of academic members).</p

    Evaluating Health Workers' Potential Resistance to New Interventions: A Role for Discrete Choice Experiments

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    BACKGROUND: The currently recommended approach for preventing malaria in pregnancy (MiP), intermittent preventive treatment with sulphadoxine-pyrimethamine (SP-IPT), has been questioned due to the spread of resistance to SP. Whilst trials are underway to test the efficacy of future alternative approaches, it is important to start exploring the feasibility of their implementation. METHODS AND FINDINGS: This study uses a discrete choice experiment (DCE) method to assess the potential resistance of health workers to changing strategies for control of MiP. In Ashanti region in Ghana, 133 antenatal clinic health workers were presented with 16 choice sets of two alternative policy options, each consisting of a bundle of six attributes representing certain clinical guidelines for controlling MiP (type of approach and drug used), possible associated maternal and neo-natal outcomes, workload and financial incentives. The data were analysed using a random effects logit model. Overall, staff showed a preference for a curative approach with pregnant women tested for malaria parasites and treated only if positive, compared to a preventive approach (OR 1.6; p = 0.001). Increasing the incidence of low birth weight or severe anaemia by 1% would reduce the odds of preferring an approach by 18% and 10% respectively. Midwives were more resistant to potential changes to current guidelines than lower-level cadres. CONCLUSIONS: In Ashanti Region, resistance to change by antenatal clinic workers from a policy of SP-IPT to IST would generally be low, and it would disappear amongst midwives if health outcomes for the mother and baby were improved by the new strategy. DCEs are a promising approach to identifying factors that will increase the likelihood of effective implementation of new interventions immediately after their efficacy has been proven

    Limits on WWZ and WW\gamma couplings from p\bar{p}\to e\nu jj X events at \sqrt{s} = 1.8 TeV

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    We present limits on anomalous WWZ and WW-gamma couplings from a search for WW and WZ production in p-bar p collisions at sqrt(s)=1.8 TeV. We use p-bar p -> e-nu jjX events recorded with the D0 detector at the Fermilab Tevatron Collider during the 1992-1995 run. The data sample corresponds to an integrated luminosity of 96.0+-5.1 pb^(-1). Assuming identical WWZ and WW-gamma coupling parameters, the 95% CL limits on the CP-conserving couplings are -0.33<lambda<0.36 (Delta-kappa=0) and -0.43<Delta-kappa<0.59 (lambda=0), for a form factor scale Lambda = 2.0 TeV. Limits based on other assumptions are also presented.Comment: 11 pages, 2 figures, 2 table

    Search For Heavy Pointlike Dirac Monopoles

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    We have searched for central production of a pair of photons with high transverse energies in ppˉp\bar p collisions at s=1.8\sqrt{s} = 1.8 TeV using 70pb−170 pb^{-1} of data collected with the D\O detector at the Fermilab Tevatron in 1994--1996. If they exist, virtual heavy pointlike Dirac monopoles could rescatter pairs of nearly real photons into this final state via a box diagram. We observe no excess of events above background, and set lower 95% C.L. limits of 610,870,or1580GeV/c2610, 870, or 1580 GeV/c^2 on the mass of a spin 0, 1/2, or 1 Dirac monopole.Comment: 12 pages, 4 figure

    The Dijet Mass Spectrum and a Search for Quark Compositeness in bar{p}p Collisions at sqrt{s} = 1.8 TeV

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    Using the DZero detector at the 1.8 TeV pbarp Fermilab Tevatron collider, we have measured the inclusive dijet mass spectrum in the central pseudorapidity region |eta_jet| < 1.0 for dijet masses greater than 200 Gev/c^2. We have also measured the ratio of spectra sigma(|eta_jet| < 0.5)/sigma(0.5 < |eta_jet| < 1.0). The order alpha_s^3 QCD predictions are in good agreement with the data and we rule out models of quark compositeness with a contact interaction scale < 2.4 TeV at the 95% confidence level.Comment: 11 pages, 4 figures, 2 tables, submitted to Phys. Rev. Let
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