8,154 research outputs found

    Dynamic analysis using finite elements to calculate the critical wear section of the contact wire in suburban railway overhead conductor rails

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    The purpose of this study is to determine the critical wear levels of the contact wire of the catenary on metropolitan lines. The study has focussed on the zones of contact wire where localised wear is produced, normally associated with the appearance of electric arcs. To this end, a finite element model has been developed to study the dynamics of pantograph-catenary interaction. The model includes a zone of localised wear and a singularity in the contact wire in order to simulate the worst case scenario from the point of view of stresses. In order to consider the different stages in the wire wear process, different depths and widths of the localised wear zone were defined. The results of the dynamic simulations performed for each stage of wear let the area of the minimum resistant section of the contact wire be determined for which stresses are greater than the allowable stress. The maximum tensile stress reached in the contact wire shows a clear sensitivity to the size of the local wear zone, defined by its width and depth. In this way, if the wear measurements taken with an overhead line recording vehicle are analysed, it will be possible to calculate the potential breakage risk of the wire. A strong dependence of the tensile forces of the contact wire has also been observed. These results will allow priorities to be set for replacing the most critical sections of wire, thereby making maintenance much more efficient. The results obtained show that the wire replacement criteria currently borne in mind have turned out to be appropriate, although in some wear scenarios these criteria could be adjusted even more, and so prolong the life cycle of the contact wire

    Potential of mathematical modeling in fruit quality

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    A review of mathematical modeling applied to fruit quality showed that these models ranged inresolution from simple yield equations to complex  representations of processes as respiration, photosynthesis and assimilation of nutrients. The latter models take into account complex  genotype environment interactions to estimate their effects on growth and yield. Recently, models are used to estimate seasonal changes in quality traits as fruit size, dry matter, water content and the concentration of sugars and acids, which are very important for flavor and aroma. These models have demonstrated their ability to generate relationships between physiological variables and quality attributes (allometric relations). This new kind of hybrid models has sufficient complexity to predict quality traits behavior

    Wunderlich syndrome (spontaneous renal hematoma) as a cause of acute abdomen: a case report

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    Spontaneous renal hemorrhage, also known as Wünderlich syndrome, is a rare condition that can be life-threatening and consists of the onset of sudden hemorrhage into the subcapsular and perirenal spaces. It can be lethal as it goes unnoticed and requires aggressive treatment. The entity lies mainly in neoplasms, the malignant ones being the most common. We present the case of a 63-year-old female patient with acute abdomen clinic, a diagnostic laparoscopy was performed and renal hematoma was evidenced as the cause of the symptoms. It was managed conservatively without any complications. We emphasize the importance of keeping in mind Wünderlich syndrome as a differential diagnosis to instigate early treatment for a better outcome.

    Magnetic and structural-properties of electrodeposited Co1-xPx amorphous ribbons

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    The specific magnetic moment, coercive force, anisotropy field, and saturation magnetostriction constant have been measured in Co(1-x)P(x) amorphous ribbons with 0.04 less-than-or-equal-to x less-than-or-equal-to 0.27. Differential scanning calorimetry, x-ray diffraction, and transmission electron microscopy analysis have been made in order to study the transition from the amorphous state to the crystalline one. Results suggest that transition takes place when x decreases from 0.19

    Ventricular arrhythmias in patients with functional mitral regurgitation and implantable cardiac devices: implications of mitral valve repair with Mitraclip

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    Background: Limited information has been reported regarding the impact of percutaneous mitral valve repair (PMVR) on ventricular arrhythmic (VA) burden. The aim of this study was to address the incidence of VA and appropriate antitachycardia implantable cardiac defibrillator (ICD) therapies before and after PMVR. Methods: We retrospectively analyzed all consecutive patients with heart failure with reduce left ventricular ejection fraction (LVEF), functional mitral regurgitation (FMR) grade 3+ or 4+ and an active ICD or cardiac resynchronizer who underwent PMVR in any of the eleven recruiting centers. Only patients with complete available device VA monitoring from one-year before to one year after PMVR were included. Baseline clinical and echocardiographic characteristics were collected before PMVR and at 12-months follow-up. Results: Ninety-three patients (68.2+/-10.9 years old, male 88.2%) were enrolled. PMVR was successfully performed in all patients and device success at discharge was 91.4%. At 12-month follow-up, we observed a significant reduction in mitral regurgitation severity, NT-proBNP and prevalence of severe pulmonary hypertension and severe kidney disease. Patients also referred a significant improvement in NYHA functional class and showed a non-significant trend to reserve left ventricular remodeling. After PMVR a significant decrease in the incidence of non-sustained ventricular tachycardia (VT) (5.0+/-17.8 vs. 2.7+/-13.5, P=0.002), sustained VT or ventricular fibrillation (0.9+/-2.5 vs. 0.5+/-2.9, P=0.012) and ICD antitachycardia therapies (2.5+/-12.0 vs. 0.9+/-5.0, P=0.033) were observed. Conclusions: PMVR was related to a reduction in arrhythmic burden and ICD therapies in our cohort

    Association of myostatin, a cytokine released by muscle, with inflammation in rheumatoid arthritis

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    Instituto Mexicano del Seguro Social, Fondo de Investigacion en Salud, FIS/IMSS/PROT/MD16/1565Supplemental Digital Content is available in the text Myostatin is a cytokine produced and released by myocytes that might have an outstanding role not only in muscle wasting during cachexia but also in inflammation. Herein we explore the association between myostatin levels and inflammatory parameters in rheumatoid arthritis (RA). One hundred twenty-seven women without rheumatic diseases and 84 women with a diagnosis of RA were assessed in a cross-sectional study. Outcomes reflecting the activity of the arthritis including Disease Activity Score (DAS28-ESR) and impairment in functioning by the Health Assessment Questionnaire-Disability Index were assessed in RA. We obtained Skeletal muscle mass index (SMI), fat-free mass index (FFMI), and fat mass index using dual-energy x-ray absorptiometry. Serum myostatin was determined by enzyme-linked immunosorbent assay. Myostatin levels were correlated with disease activity and parameters of muscle mass. The SMI was lower and concentration of myostatin was higher in RA patients than in controls (P = .008 and P < .001, respectively). Myostatin significantly positively correlated with C-reactive protein (rho = 0.48, P < .001), erythrocyte sedimentation rate (rho = 0.28, P = .009), and DAS28-ESR (rho = 0.22, P = .04), and negatively correlated with SMI (rho = −0.29, P = .008), (FFMI) (rho = −0.24, P = .027). In the multivariate logistic regression analysis, levels of myostatin remained associated with disease activity in RA (P = .027). In our study, myostatin was associated with disease activity in RA patients, suggesting a mechanistic link between myostatin, muscle wasting and inflammation in RA

    Egg consumption and dyslipidemia in a Mediterranean cohort

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    Introduction and objectives: Our aim was to prospectively evaluate the association between egg consumption and dyslipidemia in a Mediterranean cohort. Methods: We followed-up 13,104 Spanish university graduates for a mean period of 8 years. Dietary habits at baseline were assessed using a validated semi-quantitative 136-item food-frequency questionnaire. Self-reported blood concentrations of total cholesterol, high-density lipoproteins cholesterol (HDL-c) and triglycerides were evaluated according to categories of egg consumption after 6 and 8 years of follow-up. We also assessed the association between baseline egg consumption and the incidence of hypercholesterolemia, low HDL-c concentrations and hypertriglyceridemia during follow-up. Results: We observed a significant inverse association for intermediate levels of egg consumption (2 to 4 eggs/week vs. less than 1 egg/week) and hypertriglyceridemia with OR = 0.71 (95% confidence interval [CI]: 0.54 to 0.93, p < 0.05) in the multivariable-adjusted model. Using HDL-c values after 8-year follow-up, we found an association between higher egg consumption and lower HDL-c levels (p for trend = 0.02) with an adjusted difference of –4.01 mg/dl (-7.42 to -0.61) for > 4 vs. < 1 egg/week. Lower means of triglycerides were found in each of the three upper categories of egg consumption compared to the lowest category (< 1 egg/week) with significant results for some of these categories both after 6 and 8 year follow-up. Conclusions: Our data do not support that higher egg consumption was associated with abnormal blood levels of total cholesterol or triglycerides; an inverse association with HDL-c as a quantitative variable was found only in one of our analyses.Introducción y objetivos: evaluar prospectivamente la asociación entre el consumo de huevo y el riesgo de dislipidemia en una cohorte mediterránea. Métodos: se siguieron 13.104 graduados universitarios españoles durante un periodo medio de 8 años. La dieta se evaluó al inicio utilizando un cuestionario semicuantitativo de frecuencia de consumo de alimentos repetidamente validado. Las concentraciones sanguíneas de colesterol total, lipoproteínas de alta densidad (HDL-c) y triglicéridos autorreferidas fueron evaluadas según categorías de consumo de huevo tras 6 y 8 años de seguimiento. También se evaluó la asociación entre el consumo basal de huevo y la incidencia de hipercolesterolemia, concentraciones bajas de HDL-c e hipertrigliceridemia durante el seguimiento. Resultados: se observó una asociación entre los niveles intermedios de consumo de huevo (2-4 unidades/semana frente a < 1 unidad/semana) y menor riesgo de hipertrigliceridemia con OR = 0,71 (intervalo de confianza del 95% [IC]: 0,54 a 0,93, p < 0,05) en el modelo más ajustado. Tras 8 años de seguimiento, encontramos una asociación entre un mayor consumo de huevo y menores niveles de HDL-c (p tendencia lineal = 0,02) con una diferencia ajustada de -4,01 mg/dl (-7,42 a -0,61) para > 4 vs. < 1 unidad/semana. Se encontraron menores concentraciones de triglicéridos en las tres categorías superiores de consumo de huevo en comparación con la inferior con resultados significativos para algunas de estas categorías después de 6 y 8 años de seguimiento. Conclusiones: un mayor consumo de huevo no se asoció con niveles anormales de colesterol total o triglicéridos; se encontró una asociación inversa con HDL-c como variable cuantitativa solo en uno de nuestros análisis

    Pelvic floor dysfunction in Mexican women

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    Background: Pelvic floor dysfunction (PFD) is a term used to describe a variety of disorders that involve moderate to severe impairment of the pelvic floor muscles. Throughout their lives, up to 46% of women will present at least one form of PFD and may even have a combination of this pathology. These afflictions have a profound influence on women’s general well-being and quality of life, as well as being an immense economic burden for global health systems. Methods: This was a populational study which used surveys made in Google Forms of different questionnaires validated in Spanish [Urinary Incontinence Questionnaire (ICIQ), Female Sexual Function Index (IFSF), CPPQ Questionnaire for chronic pelvic pain, Wexner anal incontinence scale and quality of life] which were taken by women with access to social networks and who agreed to carry out an anonymous survey. Results: Seven hundred and twenty-one participants were evaluated, a total of 61.4% (443) responded positively to involuntary loss of urine, 35% had presented discomfort during sexual activity or lack of sexual interest, 14% had genital pain and 16% reported involuntary loss of feces or gas. Of all the patients that answered any of these questioners positively, only 33% had sought medical attention in the past. Conclusions: We concluded that in our population PFD is underdiagnosed. Our populations prevalence of urinary incontinence and pelvic pain is within the internationally described margins; anal incontinence is above international reports, and our population presented a lower prevalence of sexual dysfunction. With this new information we must impulse awareness to guide various preventive behaviors

    Percutaneous treatment with Mitraclip for functional mitral regurgitation: medium-term follow up according to left ventricular function

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    Background: Functional mitral regurgitation (FMR) is a bad prognosis condition despite optimal medical treatment. Nowadays there is an open debate about the surgical versus percutaneous treatment. The main objective of this study is to evaluate the mid-term follow up clinical outcomes of patients with FMR treated with MitraClip((R)) system, according to their left ventricular ejection fraction (LVEF). Methods: Data was obtained from two experienced centers in transcatheter mitral valve repair (TMVR). All consecutive cases of severe FMR undergoing TMVR in both centers with the same inclusion criteria were included prospectively in this study and followed-up. Periodical follow-ups with clinical and echocardiographic evaluation were scheduled from the baseline procedure, at 3 months and then yearly. Results: From October 2015 to October 2019, a total of 119 patients with FMR at 2 centers in Spain underwent TMVR with the MitraClip((R)) procedure and were included in this study. The mean age was 73.8+/-8.9 years old and 32 patients (26.9%) were female. A 39.5% of cases [47] had a LVEF 30% (group 2). There was a similar distribution in cardiovascular risk factors, age and other diseases. All MitraClip((R)) implantations were elective and procedural success was achieved in 110 patients (92.4%) with a similar distribution between the groups. There were no differences in procedural time and the number of implanted clips. The median follow-up was 22.6 months (IQR, 11.43-34.98 months). The primary combined endpoint occurred in the 41.6% of the global cohort, 57.5% in group 1 and 30.99% in group 2 (P=0.036). LVEF was associated to the main event in the multivariate analysis (HR 2.09, 95% CI: 1.12-3.89; P=0.02). Conclusions: The MitraClip edge-to-edge technique is a safe and effective procedure for the treatment of FMR. In this study, patients with LVEF >30% treated with Mitraclip presented better clinical cardiovascular outcomes than those with a LVEF </=30%. Regardless clinical outcomes, at the end of the follow-up, there was a sustained reduction in MR grades and an important improvement in NYHA functional class
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