700 research outputs found

    Hybrid receiver study

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    The results are presented of a 4 month study to design a hybrid analog/digital receiver for outer planet mission probe communication links. The scope of this study includes functional design of the receiver; comparisons between analog and digital processing; hardware tradeoffs for key components including frequency generators, A/D converters, and digital processors; development and simulation of the processing algorithms for acquisition, tracking, and demodulation; and detailed design of the receiver in order to determine its size, weight, power, reliability, and radiation hardness. In addition, an evaluation was made of the receiver's capabilities to perform accurate measurement of signal strength and frequency for radio science missions

    Resting electrocardiographic and echocardiographic findings in an urban community in the Gambia

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    The presence of Left Ventricular Hypertrophy (LVH) in a patient with systemic hypertension deserves serious attention and makes its clinical diagnosis a priority. Over the years various criteriahave been proposed for the electrographic (ECG) diagnosis of LVH and the sensitivity and specificity of these criteria have been extensively studied in Caucasians. Recent evidence indicates that they areinapplicable to people of African descent. Unlike echocardiography (ECHO), the ECG is generally available, cheap but has a lower sensitivity in detecting LVH compared to echocardiography. Thisstudy was conducted to evaluate ECG criteria against 2-dimensional (2-D) guided M-mode echocardiography in the diagnosis of LVH in adult Gambians. Secondly, to determine the ECG criteria usingthe Minnesota, Araoye, Sokolow and Lyon or Wolff criteria with the overall best accuracy for the diagnosis of LVH. Two hundred and eight (208) consecutive patients with systemic hypertension (BP.140/90mmHg) with or without treatment and an age matched group of 108 non-hypertensive patients were enrolled from outpatient clinics. A questionnaire was filled. All patients were investigated with 2-D guided M-mode echocardiography and a standard 12-1ead ECG. Anthropometric measurements were also taken. The gold standard was the Penn formula to determine the left ventricular mass index (of 125 g/m2 in males and 110 g/m2 in females as the cut-off for LVH). Using this gold standard the prevalence of echocardiographic LVH was 47.5% and 27.8 % in the hypertensives and non-hypertensives respectively (P 0.05). Sokolow and Lyon criterion had overall best accuracy for the electrocardiographic diagnosis of left ventricular hypertrophyin hypertensives and is further recommended for use as such. But for non-hypertensives, the Wolff criterion had overall best accuracy

    The Canadian Neuromuscular Disease Registry: Connecting Patients to National and International Research Opportunities

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    Introduction Patient registries serve an important role in rare disease research, particularly for the recruitment and planning of clinical trials. The Canadian Neuromuscular Disease Registry was established with the primary objective of improving the future for neuromuscular (NM) patients through the enablement and support of research into potential treatments. Methods In this report, we discuss design and utilization of the Canadian Neuromuscular Disease Registry with special reference to the paediatric cohort currently enrolled in the registry. Results As of July 25, 2017, there are 658 paediatric participants enrolled in the registry, 249 are dystrophinopathies (229 are Duchenne muscular dystrophy), 57 are myotonic dystrophy participants, 98 spinal muscular atrophy participants and 65 are limb girdle muscular dystrophy. A total of 175 patients have another NM diagnosis. The registry has facilitated 20 clinical trial inquiries, 5 mail-out survey studies and 5 other studies in the paediatric population. Discussion The strengths of the registry are discussed. The registry has proven to be an invaluable tool to NM disease research and has increased Canada’s visibility as a competitive location for the conduct of clinical trials for NM therapies

    IFNAR1-Signalling Obstructs ICOS-mediated Humoral Immunity during Non-lethal Blood-Stage Plasmodium Infection

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    Funding: This work was funded by a Career Development Fellowship (1028634) and a project grant (GRNT1028641) awarded to AHa by the Australian National Health & Medical Research Council (NHMRC). IS was supported by The University of Queensland Centennial and IPRS Scholarships. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

    Environmental movements in space-time: the Czech and Slovak republics from Stalinism to post-socialism

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    To demonstrate the role of space and time in social movements, the paper analyses the evolution and context of the environmental movement in the Czech and Slovak republics from 1948 to 1998. It shows that the movement's identity was formed under socialism and that political opportunity and resource availability changed markedly over time, as did its organisational and spatial structure. The movement played a significant part in the collapse of the socialist regime, but in the 1990s was marginalised in the interests of building a market economy and an independent Slovakia. Nevertheless a diverse and flexible range of groups existed by the late 1990s. The successive space-times allow analysis of the multiple and changing variables that influence the geography of social movements

    HIV's evasion of the cellular immune response

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    Despite a strong cytotoxic T-lymphocyte (CTL) response directed against viral antigens, untreated individuals infected with the human immunodeficiency virus (HIV-1) develop AIDS, We have found that primary T cells infected with HIV-1 downregulate surface MHC class I antigens and are resistant to lysis by HLA-A2-restricted CTL clones. In contrast, cells infected with an HIV-1 in which the nef gene is disrupted are sensitive to CTLs in an MHC and peptide-specific manner. In primary T cells HLA-A2 antigens are downmodulated more dramatically than total MHC class I antigens, suggesting that nef selectively downmodulates certain MHC class I antigens. In support of this, studies on ceils expressing individual MHC class I alietes have revealed that nef does not downmodulate HLA-C and HLA-E antigens, This selective downmodulation allows Infected cells to maintain resistance to certain natural killer cells that lyse infected cells expressing low levels of MHC class I antigens. Downmodulation of MHC class I HLA-A2 antigens occurs not only in primary T cells, but also in B and astrocytoma cell lines. No effect of other HIV-1 accessory proteins such as vpu and vpr was observed. Thus Nef is a protein that may promote escape of HIV-1 from immune surveillance.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75570/1/j.1600-065X.1999.tb01283.x.pd

    A National Spinal Muscular Atrophy Registry for Real-World Evidence.

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    BACKGROUND: Spinal muscular atrophy (SMA) is a devastating rare disease that affects individuals regardless of ethnicity, gender, and age. The first-approved disease-modifying therapy for SMA, nusinursen, was approved by Health Canada, as well as by American and European regulatory agencies following positive clinical trial outcomes. The trials were conducted in a narrow pediatric population defined by age, severity, and genotype. Broad approval of therapy necessitates close follow-up of potential rare adverse events and effectiveness in the larger real-world population. METHODS: The Canadian Neuromuscular Disease Registry (CNDR) undertook an iterative multi-stakeholder process to expand the existing SMA dataset to capture items relevant to patient outcomes in a post-marketing environment. The CNDR SMA expanded registry is a longitudinal, prospective, observational study of patients with SMA in Canada designed to evaluate the safety and effectiveness of novel therapies and provide practical information unattainable in trials. RESULTS: The consensus expanded dataset includes items that address therapy effectiveness and safety and is collected in a multicenter, prospective, observational study, including SMA patients regardless of therapeutic status. The expanded dataset is aligned with global datasets to facilitate collaboration. Additionally, consensus dataset development aimed to standardize appropriate outcome measures across the network and broader Canadian community. Prospective outcome studies, data use, and analyses are independent of the funding partner. CONCLUSION: Prospective outcome data collected will provide results on safety and effectiveness in a post-therapy approval era. These data are essential to inform improvements in care and access to therapy for all SMA patients
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