1,571 research outputs found

    Cholesterol and coronary heart disease: screening and treatment

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    Coronary heart disease (CHD) is a major cause of morbidity and mortality in the United Kingdom, accounting for just under one quarter of all deaths in 1995: 27% among men and 21% among women.1 Although many CHD deaths occur among elderly people, CHD accounts for 31% of male and 13% of female deaths within the 45–64 age group

    MOD-0A 200 kW wind turbine generator design and analysis report

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    The design, analysis, and initial performance of the MOD-OA 200 kW wind turbine generator at Clayton, NM is documented. The MOD-OA was designed and built to obtain operation and performance data and experience in utility environments. The project requirements, approach, system description, design requirements, design, analysis, system tests, installation, safety considerations, failure modes and effects analysis, data acquisition, and initial performance for the wind turbine are discussed. The design and analysis of the rotor, drive train, nacelle equipment, yaw drive mechanism and brake, tower, foundation, electricl system, and control systems are presented. The rotor includes the blades, hub, and pitch change mechanism. The drive train includes the low speed shaft, speed increaser, high speed shaft, and rotor brake. The electrical system includes the generator, switchgear, transformer, and utility connection. The control systems are the blade pitch, yaw, and generator control, and the safety system. Manual, automatic, and remote control are discussed. Systems analyses on dynamic loads and fatigue are presented

    Role of impact parameter in branching reactions: Chemical accelerator studies of the reaction Xe++CH4→XeCH3 ++H

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    This is the publisher's version, also available electronically from http://scitation.aip.org/content/aip/journal/jcp/74/9/10.1063/1.441716.Integral reaction cross sections and product velocity distributions have been measured for the ion–molecule reaction Xe+(CH4,H)XeCH3 + over the relative reactant translational energy range of 0.7–5.5 eV by chemical accelerator techniques. The kinematic results indicate that reaction proceeds in a direct manner by a rebound mechanism over the energy range studied, suggesting that this substitution reaction occurs predominantly in small impact parameter collisions. This finding contrasts with the results obtained for the competing reaction, Xe+(CH4,CH3)XeH+, where the strong forward scattering of the XeH+ product indicates that H‐atom abstraction occurs primarily in large impact parameter collisions

    The MOD-OA 200 kilowatt wind turbine generator design and analysis report

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    The project requirements, approach, system description, design requirements, design, analysis, system tests, installation safety considerations, failure modes and effects analysis, data acquisition, and initial performance for the MOD-OA 200 kw wind turbine generator are discussed. The components, the rotor, driven train, nacelle equipment, yaw drive mechanism and brake, tower, foundation, electrical system, and control systems are presented. The rotor includes the blades, hub and pitch change mechanism. The drive train includes the low speed shaft, speed increaser, high speed shaft, and rotor brake. The electrical system includes the generator, switchgear, transformer, and utility connection. The control systems are the blade pitch, yaw, and generator control, and the safety system. Manual, automatic, and remote control and Dynamic loads and fatigue are analyzed

    Human immunodeficiency virus rebound after suppression to < 400 copies/mL during initial highly active antiretroviral therapy regimens, according to prior nucleoside experience and duration of suppression

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    This study evaluated 1433 human immunodeficiency virus (HIV)-infected patients starting highly active antiretroviral therapy (HAART), 409 (28%) of whom had prior nucleoside experience and achieved an HIV load of <400 copies/mL by 24 weeks of therapy. Three hundred seven patients experienced virus rebound during a total of 2773.3 person-years of follow-up. There was a higher rate of virus rebound among the patients with pre-HAART nucleoside experience (relative hazard [RH], 2.86; 95% confidence interval, 2.22-3.84; P < .0001) and a decreasing rate of virus rebound with increasing duration of virus suppression (i.e., time since achieving a virus load of <400 HIV RNA copies/mL) among both the nucleoside-experienced and naive patients (P < .0001), but the difference between the groups persisted into the third year of follow-up (P = .0007). Even patients who had experienced <2 months of nucleoside therapy before beginning HAART had an increased risk of virus rebound (RH, 1.95; P = .009). It appears that only a small period of pre-HAART nucleoside therapy is sufficient to confer a disadvantage, in terms of risk of virus rebound, that persists for several years

    Treatment exhaustion of highly active antiretroviral therapy (HAART) among individuals infected with HIV in the United Kingdon: multicentre cohort study

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    Objectives: To investigate whether there is evidence that an increasing proportion of HIV infected patients is starting to experience increases in viral load and decreases in CD4 cell count that are consistent with exhaustion of available treatment options. Design: Multicentre cohort study. Setting: Six large HIV treatment centres in southeast England. Participants: All individuals seen for care between 1 January 1996 and 31 December 2002. Main outcome measures: Exposure to individual antiretroviral drugs and drug classes, CD4 count, plasma HIV RNA burden. Results: Information is available on 16 593 individuals (13 378 (80.6%) male patients, 10 340 (62.3%) infected via homosexual or bisexual sex, 4426 (26.7%) infected via heterosexual sex, median age 34 years). Overall, 10 207 of the 16 593 patients (61.5%) have been exposed to any antiretroviral therapy. This proportion increased from 41.2% of patients under follow up at the end of 1996 to 71.3% of those under follow up in 2002. The median CD4 count and HIV RNA burden of patients under follow up in each year changed from 270 cells/mm3 and 4.34 log10 copies/ml in 1996 to 408 cells/mm3 and 1.89 log10 copies/ml, respectively, in 2002. By 2002, 3060 (38%) of patients who had ever been treated with antiretroviral therapy had experienced all three main classes. Of these, around one quarter had evidence of “viral load failure” with all these three classes. Patients with three class failure were more likely to have an HIV RNA burden > 2.7 log10 copies/ml and a CD4 count < 200 cells/mm3. Conclusions: The proportion of individuals with HIV infection in the United Kingdom who have been treated has increased gradually over time. A substantial proportion of these patients seem to be in danger of exhausting their options for antiretroviral treatment. New drugs with low toxicity, which are not associated with cross resistance to existing drugs, are urgently needed for such patients

    Identification of a gene for an ancient cytokine, interleukin 15-like, in mammals; interleukins 2 and 15 co-evolved with this third family member, all sharing binding motifs for IL-15Rα

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    Interleukins 2 and 15 (IL-2 and IL-15) are highly differentiated but related cytokines with overlapping, yet also distinct functions, and established benefits for medical drug use. The present study identified a gene for an ancient third IL-2/15 family member in reptiles and mammals, interleukin 15-like (IL-15L), which hitherto was only reported in fish. IL-15L genes with intact open reading frames (ORFs) and evidence of transcription, and a recent past of purifying selection, were found for cattle, horse, sheep, pig and rabbit. In human and mouse the IL-15L ORF is incapacitated. Although deduced IL-15L proteins share only ~21&nbsp;% overall amino acid identity with IL-15, they share many of the IL-15 residues important for binding to receptor chain IL-15R&alpha;, and recombinant bovine IL-15L was shown to interact with IL-15R&alpha; indeed. Comparison of sequence motifs indicates that capacity for binding IL-15R&alpha; is an ancestral characteristic of the IL-2/15/15L family, in accordance with a recent study which showed that in fish both IL-2 and IL-15 can bind IL-15R&alpha;. Evidence reveals that the species lineage leading to mammals started out with three similar cytokines IL-2, IL-15 and IL-15L, and that later in evolution (1) IL-2 and IL-2R&alpha; receptor chain acquired a new and specific binding mode and (2) IL-15L was lost in several but not all groups of mammals. The present study forms an important step forward in understanding this potent family of cytokines, and may help to improve future strategies for their application in veterinarian and human medicine
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