Wos İndeksli Yayınlar Koleksiyonu

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Subject: search.filters.subject.Fatigue

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    New Perspective On Fatigue In Hemodialysis Patients With Preserved Ejection Fraction: Diastolic Dysfunction Fatigue And Diastolic Dysfunction
    (2022) Akbay, Ertan; Akinci, Sinan; Coner, Ali; Adar, Adem; Genctoy, Gultekin; Demir, Ali Riza; https://orcid.org/0000-0002-9146-0621; https://orcid.org/0000-0001-5250-5404; AAD-5479-2021; AAD-5564-2021
    The relationship between diastolic dysfunction and fatigue in hemodialysis patients with preserved ejection fraction is unknown. In this context, the objective of this study is to assess fatigue using the relevant scales and to demonstrate its relationship with diastolic dysfunction. The patients who underwent hemodialysis were evaluated prospectively. Patients' fatigue was assessed using the Visual Analogue Scale to Evaluate Fatigue Severity (VAS-F). The echocardiographic works were performed as recommended in the American Society of Echocardiography guidelines. A total of 94 patients [mean age 64.7 +/- 13.5 years, 54 males (57.4%)] were included in the study. The median VAS-F score of these patients was 68.5 (33.25-91.25), and they were divided into two groups according to this value. Peak myocardial velocities during early diastole (e ') and tricuspid annular plane systolic excursion (TAPSE) values were found to be significantly lower in the group with high VAS-F scores, whereas the early diastolic flow velocities (E)/e ' ratio and pulmonary artery peak systolic pressures (PAP) were found to be significantly higher (p < 0.05, for all). E/e ' ratio (r 0.311, p 0.002) and PAP (r 0.281, p 0.006) values were found to be positively correlated with the VAS-F score, as opposed to the TAPSE (r - 0.257, p 0.012) and e ' (r - 0.303, p 0.003) values, which were found to be negatively correlated with the VAS-F score. High fatigue scores in hemodialysis patients may be associated with diastolic dysfunction. In addition, in our study, we determined the correlation of VAS-F score with E/e ' ratio, PAP and TAPSE.
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    Risk-based inspection planning for internal surface defected oil pipelines exposed to fatigue
    (2022) Sozen, Levent; Yurdakul, Mustafa; Ic, Yusuf Tansel
    The pipelines should be inspected periodically to minimize the probability of failure. The timing of these periodic inspections can be determined by a risk assessment that considers the probability of failure of the pipeline and the potential undesirable effects of the chemical transferred. These are referred to as risk-based inspection methods in the literature. We evaluate pipelines with internal surface defects and under the effect of variable pressure in this study. Internal surface defects were considered production-related, and there is a lack of studies in the literature examining such kinds of defects. These defects generate the concentration of stress on the pipeline section. The reliability variation of the pipeline depends on some factors, namely, surface defect ge-ometry, the pipe section geometry, and the mechanical properties of the pipe. Fatigue is accepted as the crucial damage mechanism. The cause of variable load is considered as the number of operations. As a result of the study, the probability of fatigue failure for pipelines with internal surface defects was evaluated. Then, a new approach was proposed for risk-based inspection planning of the pipelines. As a case study, the probability of fatigue failure on a fuel pipeline established between a refinery and an oil terminal operating in Turkey was calculated. Also, we tried to determine the most appropriate inspection time. The data used in the planning phase was collected from a measurement process performed on the pipeline using PIG (Pipe Inspection Gauge). Finite element analysis was used to calculate stress concentration factors. Finally, we used the Monte Carlo simulation method to obtain the probability of failure.