1,063 research outputs found

    Wrist Camera Orientation for Effective Telerobotic Orbital Replaceable Unit (ORU) Changeout

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    The Hydraulic Manipulator Testbed (HMTB) is the kinematic replica of the Flight Telerobotic Servicer (FTS). One use of the HMTB is to evaluate advanced control techniques for accomplishing robotic maintenance tasks on board the Space Station. Most maintenance tasks involve the direct manipulation of the robot by a human operator when high-quality visual feedback is important for precise control. An experiment was conducted in the Systems Integration Branch at the Langley Research Center to compare several configurations of the manipulator wrist camera for providing visual feedback during an Orbital Replaceable Unit changeout task. Several variables were considered such as wrist camera angle, camera focal length, target location, lighting. Each study participant performed the maintenance task by using eight combinations of the variables based on a Latin square design. The results of this experiment and conclusions based on data collected are presented

    Bases moleculares da interação celular em modelos de reprodução e câncer: identificação de proteínas e mecanismos envolvidos

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    La interacción entre las células somáticas y entre las gametas involucra una serie de eventos moleculares que no han sido dilucidados totalmente. Nuestro grupo de investigación ha desarrollado proyectos dirigidos a profundizar el conocimiento de dichos eventos. Los estudios han comprendido el análisis de moduladores de la funcionalidad espermática (ej. efecto de la temperatura de incubación, las concentraciones del ión calcio, los anticuerpos antiespermáticos de fluidos biológicos en la motilidad, la capacitación y la exocitosis acrosomal). Asimismo, hemos caracterizado componentes del espermatozoide (ej. CaM Kinasa IV, proacrosina/acrosina) y de secreciones del tracto femenino (ej. Grp78/BiP), evaluado su rol en el desarrollo de capacidad fecundante y, en algunos casos, investigado su relación con la infertilidad. En años recientes, nuestros proyectos se han extendido al estudio de las cadherinas en eventos de adhesión celular durante la fecundación; hemos caracterizado la expresión de cadherina epitelial y neural en tejidos reproductivos y gametas y evaluado su participación en la fecundación. Dada su reconocida relevancia en el cáncer, hemos abordado estudios en diversos modelos tumorales. Nuestras investigaciones han contribuido a la comprensión de los eventos de interacción de las gametas durante la fecundación así como entre las células somáticas durante la progresión tumoral.Cell-cell interaction between somatic cells as well as gametes involves molecular events that have not been completely elucidated. Our research group has developed projects aimed at studying proteins and mechanisms participating in these interactions. Several modulators of sperm functions have been analyzed (i.e. incubation temperature, calcium ion concentration, and antisperm antibodies present in biological fluids upon sperm motility, capacitation and acrosomal exocytosis). In addition, proteins from spermatozoa (i.e. CaM Kinase IV, proacrosin/acrosin) and from secretions of the female tract (Grp78/BiP) have been characterized, and their role in the development of sperm fertilizing ability assessed. In some cases, their relationship with infertility was evaluated. In recent years, our projects have been extended to study members of the cadherin superfamily and related proteins; in particular, the expression of epithelial and neural cadherin in reproductive tissues and gametes was characterized and evidence of their participation in fertilization-related cell-cell adhesion events shown. Based on the vast evidence of the role of these proteins in tumor progression, our current research also involves studies of cancer models. Our projects have contributed to the understanding of the molecular basis of cell-cell interaction during fertilization as well as during tumor progression.A interação entre as células somáticas e entre os gametas envolve uma série de eventos moleculares que não têm sido elucidados totalmente. Nosso grupo de pesquisa tem desenvolvido projetos encaminhados a aprofundar o conhecimento de tais eventos. Os estudos têm compreendido a análise de moduladores da funcionalidade espermática (ex. efeito da temperatura de incubação, as concentrações do íon cálcio, os anticorpos antiespermáticos de fluidos biológicos na motilidade, a capacitação e a exocitose acrossomal). Do mesmo modo, caracterizamos componentes do espermatozoide (ex. CaM Kinase IV, proacrosina /acrosina) e de secreções do trato feminino (ex. Grp78/BiP), avaliamos seu papel no desenvolvimento de capacidade fecundante e, em alguns casos, investigamos sua relação com a infertilidade. Em anos recentes, nossos projetos se têm estendido ao estudo das caderinas em eventos de adesão celular durante a fecundação; temos caracterizado a expressão de caderina epitelial e neural em tecidos reprodutivos e gametas e avaliamos sua participação na fecundação. Dada sua reconhecida relevância no câncer, temos abordado estudos em diversos modelos tumorais. Nossas pesquisas têm contribuído à compreensão dos eventos de interação dos gametas durante a fecundação bem como entre as células somáticas durante a progressão tumoralFil: Vazquez, Monica Hebe. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Furlong, Laura I.. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Marin Briggiler, Clara Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Veaute, Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Veiga, Maria Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Matos, María L.. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Lapyckyj, Lara. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Gabrielli, Nieves María. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Rosso, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Arzondo, María M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Edelsztein, Nadia Yasmín. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Besso, María José. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentin

    Search for lepton-flavor violation at HERA

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    A search for lepton-flavor-violating interactions epμXe p \to \mu X and epτXe 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 λeq1βq\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 βq\beta_{\ell q} is the branching ratio of the LQ to the final-state lepton \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 λeqαλqβ/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 \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 epτXe 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

    The EuroMyositis registry: an international collaborative tool to facilitate myositis research

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    Aims: The EuroMyositis Registry facilitates collaboration across the idiopathic inflammatory myopathy (IIM) research community. This inaugural report examines pooled Registry data. Methods: Cross-sectional analysis of IIM cases from 11 countries was performed. Associations between clinical subtypes, extramuscular involvement, environmental exposures and medications were investigated. Results: Of 3067 IIM cases, 69% were female. The most common IIM subtype was dermatomyositis (DM) (31%). Smoking was more frequent in connective tissue disease overlap cases (45%, OR 1.44, 95% CI 1.09 to 1.90, p=0.012). Smoking was associated with interstitial lung disease (ILD) (OR 1.32, 95% CI 1.06 to 1.65, p=0.013), dysphagia (OR 1.43, 95% CI 1.16 to 1.77, p=0.001), malignancy ever (OR 1.78, 95% CI 1.36 to 2.33, p<0.001) and cardiac involvement (OR 2.40, 95% CI 1.60 to 3.60, p<0.001). Dysphagia occurred in 39% and cardiac involvement in 9%; either occurrence was associated with higher Health Assessment Questionnaire (HAQ) scores (adjusted OR 1.79, 95% CI 1.43 to 2.23, p<0.001). HAQ scores were also higher in inclusion body myositis cases (adjusted OR 3.85, 95% CI 2.52 to 5.90, p<0.001). Malignancy (ever) occurred in 13%, most commonly in DM (20%, OR 2.06, 95% CI 1.65 to 2.57, p<0.001). ILD occurred in 30%, most frequently in antisynthetase syndrome (71%, OR 10.7, 95% CI 8.6 to 13.4, p<0.001). Rash characteristics differed between adult-onset and juvenile-onset DM cases ('V' sign: 56% DM vs 16% juvenile-DM, OR 0.16, 95% CI 0.07 to 0.36, p<0.001). Glucocorticoids were used in 98% of cases, methotrexate in 71% and azathioprine in 51%. Conclusion: This large multicentre cohort demonstrates the importance of extramuscular involvement in patients with IIM, its association with smoking and its influence on disease severity. Our findings emphasise that IIM is a multisystem inflammatory disease and will help inform prognosis and clinical management of patients

    Multijet production in neutral current deep inelastic scattering at HERA and determination of alpha_s

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    Multijet production rates in neutral current deep inelastic scattering have been measured in the range of exchanged boson virtualities 10 < Q2 < 5000 GeV2. The data were taken at the ep collider HERA with centre-of-mass energy sqrt(s) = 318 GeV using the ZEUS detector and correspond to an integrated luminosity of 82.2 pb-1. Jets were identified in the Breit frame using the k_T cluster algorithm in the longitudinally invariant inclusive mode. Measurements of differential dijet and trijet cross sections are presented as functions of jet transverse energy E_{T,B}{jet}, pseudorapidity eta_{LAB}{jet} and Q2 with E_{T,B}{jet} > 5 GeV and -1 < eta_{LAB}{jet} < 2.5. Next-to-leading-order QCD calculations describe the data well. The value of the strong coupling constant alpha_s(M_Z), determined from the ratio of the trijet to dijet cross sections, is alpha_s(M_Z) = 0.1179 pm 0.0013(stat.) {+0.0028}_{-0.0046}(exp.) {+0.0064}_{-0.0046}(th.)Comment: 22 pages, 5 figure

    Measurement of charm fragmentation ratios and fractions in photoproduction at HERA

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    The production of D^*+, D^0, D^+, D_s^+ and Lambda_c^+ charm hadrons and their antiparticles in ep scattering at HERA was measured with the ZEUS detector using an integrated luminosity of 79 pb^-1. The measurement has been performed in the photoproduction regime with the exchanged-photon virtuality Q^2 < 1 GeV^2 and for photon-proton centre-of-mass energies in the range 130 < W < 300 GeV. The charm hadrons were reconstructed in the range of transverse momentum p_T(D, Lambda_c) > 3.8 GeV and pseudorapidity |eta(D, Lambda_c)| < 1.6. The production cross sections were used to determine the ratio of neutral and charged D-meson production rates, R_u/d, the strangeness-suppression factor, gamma_s, and the fraction of charged D mesons produced in a vector state, P_v^d. The measured R_u/d and gamma_s values agree with those obtained in deep inelastic scattering and in e^+e^- annihilations. The measured P_v^d value is smaller than, but consistent with, the previous measurements. The fractions of c quarks hadronising as a particular charm hadron, f(c -> D, Lambda_c), were derived in the given kinematic range. The measured open-charm fragmentation fractions are consistent with previous results, although the measured f(c -> D^*+) is smaller and f(c -> Lambda_c^+) is larger than those obtained in e^+e^- annihilations. These results generally support the hypothesis that fragmentation proceeds independently of the hard sub-process.Comment: 29 pages, 5 figures, 6 tables; minor text revision

    Inclusive jet cross sections and dijet correlations in D±D^{*\pm} photoproduction at HERA

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    Inclusive jet cross sections in photoproduction for events containing a DD^* meson have been measured with the ZEUS detector at HERA using an integrated luminosity of 78.6pb178.6 {\rm pb}^{-1}. The events were required to have a virtuality of the incoming photon, Q2Q^2, of less than 1 GeV2^2, and a photon-proton centre-of-mass energy in the range 130<Wγp<280GeV130<W_{\gamma p}<280 {\rm GeV}. The measurements are compared with next-to-leading-order (NLO) QCD calculations. Good agreement is found with the NLO calculations over most of the measured kinematic region. Requiring a second jet in the event allowed a more detailed comparison with QCD calculations. The measured dijet cross sections are also compared to Monte Carlo (MC) models which incorporate leading-order matrix elements followed by parton showers and hadronisation. The NLO QCD predictions are in general agreement with the data although differences have been isolated to regions where contributions from higher orders are expected to be significant. The MC models give a better description than the NLO predictions of the shape of the measured cross sections.Comment: 43 pages, 12 figures, charm jets ZEU

    Dissociation of virtual photons in events with a leading proton at HERA

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    The ZEUS detector has been used to study dissociation of virtual photons in events with a leading proton, gamma^* p -> X p, in e^+p collisions at HERA. The data cover photon virtualities in two ranges, 0.03<Q^2<0.60 GeV^2 and 2<Q^2<100 GeV^2, with M_X>1.5 GeV, where M_X is the mass of the hadronic final state, X. Events were required to have a leading proton, detected in the ZEUS leading proton spectrometer, carrying at least 90% of the incoming proton energy. The cross section is presented as a function of t, the squared four-momentum transfer at the proton vertex, Phi, the azimuthal angle between the positron scattering plane and the proton scattering plane, and Q^2. The data are presented in terms of the diffractive structure function, F_2^D(3). A next-to-leading-order QCD fit to the higher-Q^2 data set and to previously published diffractive charm production data is presented

    Comparison of clinical features between patients with anti-synthetase syndrome and dermatomyositis: Results from the MYONET registry.

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    OBJECTIVES To compare clinical characteristics, including the frequency of cutaneous, extramuscular manifestations, and malignancy, between adults with anti-synthetase syndrome (ASyS) and dermatomyositis (DM). METHODS Using data regarding adults from the MYONET registry, a cohort of DM patients with anti-Mi2/-TIF1ɣ/-NXP2/-SAE/-MDA5 autoantibodies, and a cohort of ASyS patients with anti-tRNA synthetase autoantibodies (anti-Jo1/-PL7/-PL12/-OJ/-EJ/-Zo/-KS) were identified. Patients with DM sine dermatitis or with discordant dual autoantibody specificities were excluded. Sub-cohorts of patients with ASyS with or without skin involvement were defined based on presence of DM-type rashes (heliotrope rash, Gottron's papules/sign, violaceous rash, shawl sign, V sign, erythroderma, and/or periorbital rash). RESULTS In total 1,054 patients were included (DM, n = 405; ASyS, n = 649). In ASyS cohort, 31% (n = 203) had DM-type skin involvement (ASyS-DMskin). A higher frequency of extramuscular manifestations, including Mechanic's hands, Raynaud's phenomenon, arthritis, interstitial lung disease, and cardiac involvement differentiated ASyS-DMskin from DM (all p< 0.001), whereas higher frequency of any of four DM-type rashes: heliotrope rash (n = 248, 61% vs n = 90, 44%), violaceous rash (n = 166, 41% vs n = 57, 9%), V sign (n = 124, 31% vs n = 28, 4%), and shawl sign (n = 133, 33% vs n = 18, 3%) differentiated DM from ASyS-DMskin (all p< 0.005). Cancer-associated myositis (CAM) was more frequent in DM (n = 67, 17%) compared with ASyS (n = 21, 3%) and ASyS-DMskin (n = 7, 3%) cohorts (both p< 0.001). CONCLUSION DM-type rashes are frequent in patients with ASyS; however, distinct clinical manifestations differentiate these patients from classical DM. Skin involvement in ASyS does not necessitate increased malignancy surveillance. These findings will inform future ASyS classification criteria and patient management

    Cluster analysis of behavioural and event-related potentials during a contingent negative variation paradigm in remitting-relapsing and benign forms of multiple sclerosis

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    <p>Abstract</p> <p>Background</p> <p>Event-related potentials (ERPs) may be used as a highly sensitive way of detecting subtle degrees of cognitive dysfunction. On the other hand, impairment of cognitive skills is increasingly recognised as a hallmark of patients suffering from multiple sclerosis (MS). We sought to determine the psychophysiological pattern of information processing among MS patients with the relapsing-remitting form of the disease and low physical disability considered as two subtypes: 'typical relapsing-remitting' (RRMS) and 'benign MS' (BMS). Furthermore, we subjected our data to a cluster analysis to determine whether MS patients and healthy controls could be differentiated in terms of their psychophysiological profile.</p> <p>Methods</p> <p>We investigated MS patients with RRMS and BMS subtypes using event-related potentials (ERPs) acquired in the context of a Posner visual-spatial cueing paradigm. Specifically, our study aimed to assess ERP brain activity in response preparation (contingent negative variation -CNV) and stimuli processing in MS patients. Latency and amplitude of different ERP components (P1, eN1, N1, P2, N2, P3 and late negativity -LN) as well as behavioural responses (reaction time -RT; correct responses -CRs; and number of errors) were analyzed and then subjected to cluster analysis.</p> <p>Results</p> <p>Both MS groups showed delayed behavioural responses and enhanced latency for long-latency ERP components (P2, N2, P3) as well as relatively preserved ERP amplitude, but BMS patients obtained more important performance deficits (lower CRs and higher RTs) and abnormalities related to the latency (N1, P3) and amplitude of ERPs (eCNV, eN1, LN). However, RRMS patients also demonstrated abnormally high amplitudes related to the preparation performance period of CNV (cCNV) and post-processing phase (LN). Cluster analyses revealed that RRMS patients appear to make up a relatively homogeneous group with moderate deficits mainly related to ERP latencies, whereas BMS patients appear to make up a rather more heterogeneous group with more severe information processing and attentional deficits.</p> <p>Conclusions</p> <p>Our findings are suggestive of a slowing of information processing for MS patients that may be a consequence of demyelination and axonal degeneration, which also seems to occur in MS patients that show little or no progression in the physical severity of the disease over time.</p
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