4,969 research outputs found

    Tracking Tools to Estimate the Quench Time Constants for Magnet Failures in LHC

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    At LHC, beam losses, with about 360 MJ of stored energy per beam at nominal collision operation, are potentially dangerous for the accelerator equipment and can also affect the operational efficiency by inducing quenches in superconducting magnets. Magnet failures may affect the beam leading to proton losses primarily in collimators and secondarily in superconducting magnets due to scattering of protons from collimator jaws. The evolution of the beam during magnet failures has been simulated using MAD-X with a variable magnetic field. The impacts of particles in the collimators have been recorded as a function of time. A second program, CollTrack, has been used to determine the loss patterns of scattered particles from each collimator as a function of the initial impact parameter. The magnets that are likely to quench are identified and an estimation of the time between the beginning of a failure and a quench is obtained by combining the results from the simulations. The time to a start of a quench is a relevant parameter to determine the dump threshold of beam loss monitors in order to optimize protection redundancy and operation smoothness for LHC

    Impact Distribution of the Beam Losses at the LHC Collimators in Case of Magnet Failures

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    During LHC operation, magnet failures may affect the beam optics leading to proton losses in the collimators. These losses, with about 360MJ of stored energy per beam at nominal collision operation, are potentially dangerous for the accelerator equipment. The LHC Machine Protection Systems ensure that the beam is extracted safely before these losses can produce any damage. As a magnet failure develops, so does the distribution of the lost particles, longitudinally along the ring as well as transversally at each collimator. The transversal impact distributions of lost particles at the most affected collimators and their evolution with time have been studied for representative magnet failures in the LHC. It has been found that the impact distribution at a given collimator can be approximated by an exponential function with time-dependent parameters. The average impact parameter ranges from about 7 to 620 ?m for the cases studied

    Investigation on the in vitro inhibitory mechanisms of resveratrol on varicella-zoster virus

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    【目的】 1、应用构建的水痘-带状疱疹病毒(VZV)报告细胞系MV9G进一步研究白黎芦醇体外抑制VZV的作用机制。 2、进一步验证应用VZV报告细胞MV9G筛选抗VZV药物并研究其作用机制的可行性。 【方法】 1、将无细胞VZV直接感染MV9G细胞(CFVs直接感染)或将带细胞VZV与MV9G细胞共培养(CAVs共培养)以激发MV9G细胞表达报告基因萤火虫荧光素酶。 2、在CFVs直接感染前或CAVs共培养不同时间点加入白黎芦醇,通过比较药物对CFVs或CAVs激发荧光素酶的抑制强度分析白黎芦醇直接灭活病毒、抑制病毒粘附和穿透、抑制病毒在细胞内复制及其时间点和可逆性。 3、通过...Objectives 1. To further investigate the in vitro inhibitory mechanism(s) of resveratrol on varicella-zoster virus (VZV) with our previously generated reporter cell line MV9G. 2. To further verify the application of VZV reporter cell line MV9G to screening for anti-VZV drug and investigating its inhibitory mechanisms. Methods 1. Cell-free VZVs (CFVs) were directly inoculated onto monolayer...学位:医学硕士院系专业:医学院_肿瘤学学号:2452010115338

    Influencia del sedentarismo en las desviaciones raquídeas de la población escolar de Léon

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    Nuestra investigación trata de evaluar los hábitos sedentarios, en los escolares de 10 y 14 años de una zona de León, y su influencia en las desviaciones raquídeas. Para la obtención de los hábitos nos basamos en el tets de Medoza, R. también se realizó una evaluación física de los niños para observar las desviaciones raquídeas. En el tratamiento de la información se utilizó el análisis de la varianza univariante y multivariante, además del análisis de componentes principales y análisis discriminante. Llegando a la conclusión, respecto al tiempo de televisión que el día de la semana que más tiempo dedican los niños a ver la televisión es discrimante de los escolares que tienen desviación raquídea

    Yearly evolution of organ damage markers in diabetes or metabolic syndrome: data from the LOD-DIABETES study

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    <p>Abstract</p> <p>Background</p> <p>Cardiovascular disease morbidity-mortality is greater in people with type 2 diabetes mellitus or metabolic syndrome. The purpose of this study was to evaluate the yearly evolution of organ damage markers in diabetes or metabolic syndrome, and to analyze the associated factors.</p> <p>Methods</p> <p>An observational prospective study was carried out in the primary care setting, involving 112 patients: 68 diabetics and 44 subjects with metabolic syndrome, subjected to 12 months of follow-up. Measurements: traditional cardiovascular risk factors (blood pressure, blood glucose, lipids, smoking, body mass index (BMI) and) and non-traditional risk factors (waist circumference, hsC Reactive Protein and fibrinogen); subclinical vascular (carotid intima-media thickness, pulse wave velocity and ankle/brachial index), cardiac (Cornell voltage-duration product), renal organ damage (creatinine, glomerular filtration and albumin/creatinine index), and antihypertensive and lipid-lowering drugs.</p> <p>Results</p> <p>At baseline, the diabetics presented a mean age of 59.9 years, versus 55.2 years in the subjects with metabolic syndrome (p = 0.03). Diastolic blood pressure, total cholesterol and HDL-cholesterol were lower among the patients with diabetes, while blood glucose and HbA1c, as well as antihypertensive and lipid-lowering drug use, were greater. At evaluation after one year, the diabetics showed a decrease in BMI (-0.39), diastolic blood pressure (-3.59), and an increase in fibrinogen (30.23 mg/dL), ankle/brachial index (0.07) and the number of patients with ankle/brachial index pathologic decreased in 6. In turn, the patients with metabolic syndrome showed an increase in HDL-cholesterol (1-91 mg/dL), fibrinogen (25.54 mg/dL), Cornell voltage-duration product (184.22 mm/ms), ankle/brachial index (0.05) and the use of antihypertensive and lipid-lowering drugs, and a reduction in serum glucose (3.74 mg/dL), HOMA, systolic (-6.76 mmHg), diastolic blood pressure (-3.29 mmHg), and pulse wave velocity (-0.72 m/s). The variable that best predicted a decrease in pulse wave velocity in subjects with metabolic syndrome was seen to be an increase in antihypertensive drug use.</p> <p>Conclusions</p> <p>The annual assessment of cardiovascular risk factors and the decrease in pulse wave velocity was more favorable in the patients with metabolic syndrome, probably influenced by the increased percentage of subjects treated with antihypertensive and lipid lowering drugs in this group.</p

    Dietary glycemic index and retinal microvasculature in adults: a cross-sectional study

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    [EN] Objective: To analyze the relationship between dietary glycemic index (GI) and retinal microvasculature in adults. Methods: This was a cross-sectional study of 300 subjects from the EVIDENT II study. Dietary GI was calculated using a validated, semi-quantitative food frequency questionnaire. Retinal photographs were digitized, temporal vessels were measured in an area 0.5–1 disc diameter from the optic disc and arteriolar-venular index (AVI) was estimated with semi-automated software. Results: AVI showed a significant difference between the tertiles of GI, after adjusting for potential confounders. The lowest AVI values were observed among subjects in the highest tertile of GI, whereas the greatest were found among those in the lowest tertile (estimated marginal mean of 0.738 vs. 0.768, p = 0.014). Conclusions: In adults, high dietary GI implies lowering AVI values regardless of age, gender and other confounding variables. Trial registration: Clinical Trials.gov Identifier: NCT02016014. Registered 9 December 2013
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