76 research outputs found

    Re-admission Rate of Patients with Ureteral Stone: A Descriptive Study

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    Introduction: Patients with acute renal colic need to choose between undergoing medical treatments and receiving interventions. The Aim of this study is to evaluate the outcomes of patients who are discharged from emergency departments with ureteral stones lesser than 6 millimeters. In doing so, the effect of diagnostic treatment approaches on clinical outcomes and referral rate is to be assessed.Patients and Methods: This study was performed on patients with ureteral stones referred to emergency department of Shohadaye Tajrish Hospital between May2015 to June 2018. A checklist was filled out for each patient and it included their complete medical history, physical examination results and paraclinical data. Patients were then studied for 4 weeks to determine referral times to hospital and clinical outcomes.Results: 105 patients include 81 men (77.14%) with average age of 37.1±12.4 years were studied. The mean stone diameter was 4.2±2.1 mm.  Most of ureteral stones were seen in the right-hand side (60 percent). 71 patients (67.6%) did not have any history of nephrolithiasis and 73 (69.5%) did not have positive family history for nephrolithiasis. Ureteral stones were still observed in 42 patients (40%) after two weeks of studies and only one patient (1.1%) had stone in Ultrasound Imaging after 4 weeks of observations.Conclusion: Most Patients (95%) with stones smaller than 6 mm responded to Medical Expulsive Therapy (MET) after 4 weeks and passed spontaneously ureteral calculi

    High Impedance Fault Detection in Power Transmission Lines Using Hilbert Transform and Instantaneous Frequency

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    Power transmission lines are vital components of today's power systems. These power lines transmit the electricity produced in power plants in high volume and with very low losses to distant areas so that it can be reached to consumer through distribution networks. In fact, these lines are the intermediary between major energy producers and distribution networks. Accordingly, these transmission lines are of a great importance and must be protected appropriately with a suitable protection system. Distance relays are widely used to protect these lines due to their convenient coordination characteristics and simplicity. High impedance fault (HIF) can be a critical challenge for distance relays due to their low current amplitude and similarity to conventional events in power systems such as capacitive bank switching. For this reason, in this paper a new approach is presented based on the instantaneous frequency variations obtained from the current RMS in order to detect the high impedance fault. This method detects high impedance faults via calculating a Detection index (DI) and considering a threshold value. The proposed method has been tested using DIgSILENT and MATLAB software in an IEEE standard 39-bus network. The presented results evidently demonstrate that the proposed method is suitable for detecting HIF and Low impedance fault (LIF). In addition, this method has a proper performance during capacitor bank switching and can well distinguish between HIF and capacitive bank switching. Moreover, the presented method is resistant to noise and also is capable to detect the faulty phase

    The relationship of myocardial and liver T2* values with cardiac function and laboratory findings in transfusion-dependent thalassemia major patients: A retrospective cardiac MRI study

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    Introduction: Cardiac complications are the leading cause of death in thalassemia patients. It is assumed that progressive iron accumulation results in myocyte damage. Myocardial T2* measurement by cardiac MRI quantifies iron overload. We aimed to study the association between left and right ventricular (LV and RV) function and iron deposition estimation by cardiac MRI T2* in a sample of Iranian patients. Methods: Cardiac MRI exams of 118 transfusion-dependent thalassemia major patients were evaluated retrospectively. Biventricular function and volume and myocardial and liver T2* values were measured. The demographic and lab data were registered. Poisson and chi-square regression analyses investigated the correlation between the T2* value and ventricular dysfunction. Results: The study participants’ mean (SD) age was 32.7y (9.02), and 47.46% were female. Forty-nine cases (41.52%) revealed at least uni-ventricular dysfunction. LV dysfunction was noted in 20 cases, whereas 47 patients revealed RV dysfunction. The risk of LV dysfunction was 5.3-fold higher in patients with cardiac T2* value less than 10msec (RR=5.3, 95% CI=1.6, 17.1, P<0.05). No association was found between age, liver T2* value, serum ferritin level, and chelation therapy with the risk of LV and RV dysfunction. Conclusion: Cardiac MRI T2* measure is a good indicator of LV dysfunction. Moreover, MRI parameters, especially RV functional measures, may have a substantial role in patient management. Therefore, cardiac MRI should be included in beta-thalassemia patients’ management strategies

    Damage signature of fatigued fabric reinforced plastics in the pulsed ultrasonic polar scan

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    This study investigates the use of both the amplitude and time-of-flight based pulsed ultrasonic polar scan (P-UPS) for the nondestructive detection and evaluation of fatigue damage in fiber reinforced composites. Several thermoplastic carbon fabric reinforced PPS specimens (CETEX), loaded under various fatigue conditions, have been scanned at multiple material spots according to the P-UPS technique in order to extract material degradation in a quantitative way. The P-UPS results indicate that shear dominated fatigued carbon/PPS goes with a reduction of shear properties combined with large fiber distortions. The P-UPS results of the tension-tension fatigued carbon/PPS samples on the other hand reveal a directional degradation of the stiffness properties, reaching a maximum reduction of -12.8% along the loading direction. The P-UPS extracted damage characteristics are fully supported by simulations, conventional destructive tests as well as visual inspection. The results demonstrate the excellent capability of the P-UPS method for nondestructively assessing and quantifying both shear-dominated and tension-tension fatigue damage in fabric reinforced plastics

    Effects of Aging Temperature on Moisture Absorption of Perforated GFRP

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    This paper examines the effects of aging on the flexural stiffness and bending loading capacity of a perforated glass fiber-reinforced epoxy composite subjected to combined moisture and elevated temperature. Specimens, in the configuration of one-quarter of a perforated GFRP tube, were aged in 60% humidity and temperatures of 40, 60, and 80°C, respectively. Moisture absorptions of the specimens were measured during the aging process, and bending tests were conducted on the specimens after aging. The SEM images were also captured to further examine the effects of the moisture absorption on the aged specimens. The results indicated that the increase in the aging temperature reduced the diffusion coefficient, thus inducing more moisture absorption by the composite and in turn causing more reduction in composite’s flexural stiffness and bending capacity. Moreover, the ability of Fick’s equation for predicting the moisture absorption rate in such perforated thin-walled composite configuration at various moisture contents and temperatures was also assessed. A semiempirical equation was developed and proposed by which the reduction of the stiffness in the perforated aged GFRP structures could be predicted

    Mechanical Validation of Perfect Tibia 3D Model Using Computed Tomography Scan

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