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In this paper, the influence of the variation in transformer oil temperature on the accuracy of the all-acoustic non-iterative method for partial discharge location in a power transformer is researched. The research can improve power transformers’ testing and monitoring, particularly given the large transformer oil temperature variations during real-time monitoring. The research is based on quantifying the contribution of oil temperature to the standard combined measurement uncertainty of the non-iterative algorithm by using analytical, statistical, and Monte Carlo methods. The contribution can be quantified and controlled. The contribution varied significantly with different mutual placements of partial discharge and acoustic sensors. The correlation between the contribution and the mean distance between partial discharge and acoustic sensors was observed. Based on these findings, the procedure to quantify and control the contribution in practice was proposed. The procedure considers the specificity of the method’s mathematical model (the assumption that the oil temperature is constant), the non-iterative algorithm’s nonlinearity, and the large variations in transformer oil temperature. Existing studies did not consider the significant effect of the oil temperature on the combined measurement uncertainty of partial discharge location influenced by those phenomena. The research is limited to partial discharge located in the transformer oil. 相似文献
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The chronic respiratory questionnaire, available as an interviewer and a self-administered instrument, includes 20 items across four domains: dyspnea (5 items), fatigue (4 items), emotional function (7 items), and mastery (4 items). When completing this instrument, patients rate their experience on a 7-point scale ranging from 1 (maximum impairment) to 7 (no impairment). The Chronic Respiratory Questionnaire has demonstrated excellent measurement properties for both discriminative and evaluative purposes and served as a model in numerous methodological studies in chronic airflow limitation and patients with chronic obstructive pulmonary disease. We performed a systematic review of the literature on the chronic respiratory questionnaire to summarize the key qualities of the chronic respiratory questionnaire and to appraise the work regarding the minimal important difference of the chronic respiratory questionnaire. This paper includes a revision of our initial definition of the minimal important difference and a methodological framework for using anchor based approaches to establish the minimal important difference pioneered by Jaeschke and colleagues. Other approaches to evaluate the minimal important difference include distribution-based methods and panel-based methods. Investigators have used all of these approaches to establish the minimal important difference for the chronic respiratory questionnaire and the results are in general agreement with the minimal important difference of 0.5 for the mean domain scores of the chronic respiratory questionnaire. As a result of this literature review and discussion at the workshop, we established several research objectives. These objectives include the exploration of presentation of quality of life information and prospective anchor-based approaches. 相似文献
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Rationale:Primary leptomeningeal melanoma is an extremely rare disease of the central nervous system. There are no standard treatment protocols with a poor prognosis in very few reported cases. Immunotherapy in primary brain melanoma has not been successfully applied so far.Patient concerns:We describe a female patient 72-year-old diagnosed in the Neurosurgery Department which presented with generalized seizures.Diagnoses:Histological examination confirmed atypical melanocytes immunohistochemically positive for melan A, HMB45 and S-100 protein in the meninges, BRAF V600E negative. Dermatological, ophthalmological examinations, and 18-FDG PET/CT were negative.Interventions:The patient was successfully treated with pembrolizumab 2 mg/kg every 3 weeks for 2 years.Outcomes:The disease was stable for 2 years and the patient had no significant toxicity.Lessons:Our report describes durable intracranial tumor response suggesting the efficacy of PD-1 inhibitor pembrolizumab for central nervous system primary leptomeningeal melanoma. 相似文献
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Hugo Sarmento Filipe Manuel Clemente Adilson Marques Zoran Milanovic Liam David Harper António Figueiredo 《Scandinavian journal of medicine & science in sports》2020,30(4):618-637
The purpose of this research was to conduct a systematic review of published articles related to the effect of recreational football on non-communicable diseases. A systematic review of Web of Science, SPORTDiscus, MEDLINE, and PubMed databases was performed according to PRISMA guidelines. Only empirical studies were included. There were no restrictions on the types of study design eligible for inclusion. The primary outcome measures result from the potential effects of recreational football on non-communicable diseases (eg, blood pressure, bone density, LDL cholesterol, and fat mass). A total of 44 articles met the inclusion criteria and were included. Recreational football is shown to: (a) decrease blood pressure and resting heart rate, improve cardiac structure and functioning, as well as increase maximal oxygen uptake in both sexes; (b) reduce cholesterol and triglycerides levels, increase insulin sensitivity, and have a positive impact on glycemic control; (c) improve bone mineralization, increase both bone mineral density and content, as well as acting as a stimulus for osteogenesis; and (d) be clearly beneficial for bone health, while slightly beneficial for body composition, muscle strength, and maximal oxygen uptake in adults with prostate cancer. The present systematic review demonstrated the benefits of recreational football practice on non-communicable diseases related to cardiovascular and bone health, body composition, type 2 diabetes, and prostate cancer. The effectiveness of recreational football on the aforementioned diseases may be related to age and gender; however, further research is required. 相似文献
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Carlos O. Weiss MD Ravi Varadhan PhD Milo A. Puhan MD PhD Andrew Vickers PhD Karen Bandeen-Roche PhD MS Cynthia M. Boyd MD MPH David M. Kent MD CM MSc 《Journal of general internal medicine》2014,29(4):653-660
Most people with a chronic disease actually have more than one, a condition known as multimorbidity. Despite this, the evidence base to prevent adverse disease outcomes has taken a disease-specific approach. Drawing on a conference, Improving Guidelines for Multimorbid Patients, the goal of this paper is to identify challenges to the generation of evidence to support the care of people with multimorbidity and to make recommendations for improvement. We identified three broad categories of challenges: 1) challenges to defining and measuring multimorbidity; 2) challenges related to the effects of multimorbidity on study design, implementation and analysis; and 3) challenges inherent in studying heterogeneity of treatment effects in patients with differing comorbid conditions. We propose a set of recommendations for consideration by investigators and others (reviewers, editors, funding agencies, policymaking organizations) involved in the creation of evidence for this common type of person that address each of these challenges. The recommendations reflect a general approach that emphasizes broader inclusion (recruitment and retention) of patients with multimorbidity, coupled with more rigorous efforts to measure comorbidity and comorbidity burden and the influence of multimorbidity on outcomes and the effects of therapy. More rigorous examination of heterogeneity of treatment effects requires careful attention to prioritizing the most important comorbid-related questions, and also requires studies that provide greater statistical power than conventional trials have provided. Relatively modest changes in the orientation of current research along these lines can be helpful in pointing to and partially addressing selected knowledge gaps. However, producing a robust evidence base to support patient-centered decision making in complex individuals with multimorbidity, exposed to many different combinations of potentially interacting factors that can modify the risks and benefits of therapies, is likely to require a clinical research enterprise fundamentally restructured to be more fully integrated with routine clinical practice. 相似文献