35 research outputs found

    Investigating the impact of the velocity of a vehicle with a nonlinear suspension system on the dynamic behavior of a Bernoulli–Euler bridge

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    AbstractSeveral authors, utilizing both experimental tests and complicated numerical models, have investigated vehicle speed's impact on a highway bridge's dynamic amplification. Although these tests and models provide reliable quantitative data on frequency contents of the interaction between the two subsystems, engineers should pay further notice to the effects of a subsystem's velocity and the type of suspension system of a vehicle moving over a structure. Hence, in this paper, the dynamic response of a bridge to a moving vehicle is considered. The car is assumed as a quarter car model with both linear and nonlinear stiffness and damping constants. Further, using the modal superposition method, a closed-form solution is obtained for the bridge's vertical response. The results obtained via numerical calculation show a significant increase in the bridge midpoint and total deflection, velocity, and acceleration by increasing the vehicle velocity. Moreover, by neglecting the nonlinear stiffness and damping coefficients of the vehicle suspension system, the bridge's dynamic response remains almost the same with respect to the numerical data. As a general conclusion, it can be claimed that the only significant parameters which can change the dynamic behavior of a bridge subjected to a moving vehicle are the speed of the car and its linear stiffness and damping constants inside its suspension system

    Quantitation in Dextrocardia on myocardial perfusion imaging: how to perform quantitative analysis using Cedars-Sinai software

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    Dextrocardia, although a rare cardiac abnormality, carries the same risk for cardiac events as other people. SPECT Myocardial perfusion imaging is a potentially helpful diagnostic tool in patients with dextrocardia. Because of swapping of lateral and septal walls on SPECT slices, although visual analysis is possible, quantitation is substantially limited. Here, we introduce a simple practical method to make quantitative analysis feasible and accurate.Dextrocardia, although a rare cardiac abnormality, carries the same risk for cardiac events as other people. SPECT Myocardial perfusion imaging is a potentially helpful diagnostic tool in patients with dextrocardia. Due to swapping of lateral and septal walls on SPECT slices, although visual analysis is possible, quantitation is substantially limited. Here, we introduce a simple practical method to make quantitative analysis feasible and accurate.

    Effect of Mobile Cell Phone Ringing on Function of Gamma Camera

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    Abstract: After the start of renal scintigraphy in a 32-year-old woman, there was an abnormal view in frame 6 that was simultaneous with the start of ringing of a mobile cell phone that was in the patient’s trousers pocket. In frame 6 of the flow phase, some bright dots were observed, suggesting photomultiplier tubes. Immediately after that frame, in spite of continued ringing of the mobile cell phone (up to 1–2 minutes), the imaging frames came back to a normal situation. In the case, electromagnetic interference from the mobile cell phone may disrupt the photoelectric functioning of photomultiplier tubes during scintigraphy

    Edema Measurement System

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    If you can’t prevent a disease, the next best thing you can do to protect your health is to detect the symptoms of a disease early on. Build-up of excess fluids in body tissues (edema) is one of the major signs of heart failure. This early sign of heart failure can easily be detected by monitoring the amount of swelling in a patient’s leg. Constant monitoring of the swelling of various limbs can provide medical professionals with key information for proper diagnosis. Vedo Medico’s Edema Measurement System (EMS) provides a non-invasive and accurate measurement of edema in the patient’s limbs. The Edema Measurement System is designed with the user in mind. EMS presents users with reliable information through an easy to use interface. The EMS is composed of four main components: EMS Inflation Unit (IU), EMS Enclosure System (ES), EMS Control Unit (CU) and PC Diagnostic System

    « The electromagnetic interference of mobile phones on the function of a gamma camera »

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    Purpose: The aim of the present study is to evaluate whether or not the electromagnetic field generated by mobile phones interferes with the function of a single-photon emission computed tomography (SPECT) gamma camera during data acquisition. Methods and materials: We tested the effects of seven models of mobile phones on one SPECT gamma camera. The mobile phones were tested when making a call, in ringing mode, and in standby mode. The gamma camera function was assessed during data acquisition from a planar source and a point source of technetium-99m with activities of 10 mCi and 3 mCi, respectively. A significant decrease in count number was considered to be electromagnetic interference (EMI). Results: The percentage of induced EMI with the gamma camera per mobile phone was in the range of 0–100%. The incidence of EMI was mainly observed in the first seconds of ringing and then mitigated in the following frames. Conclusion: Mobile phones are portable sources of electromagnetic radiation, and there is interference potential with the function of SPECT gamma cameras leading to adverse effects on the quality of the acquired images. Keywords: Electromagnetic interference (EMI), mobile phones, gamma camera, single-photon emission computed tomography (SPECT

    WEC-Sim Application for the Assessment of Wave Energy Generation in the Tyrrhenian Sea and the North Sea Through the 2-Body Point Absorber (2BPA) and the Oscillating Surge Wave Energy Converter (OSWEC)

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    In recent years, developed countries have turned their attention to clean and renewable energy, such as wind energy and wave energy that can be converted to electrical power. Companies and academic groups worldwide are investigating several wave energy ideas today. Accordingly, this thesis studies the numerical simulation of the dynamic response of the wave energy converters (WECs) subjected to the ocean waves. This study considers a two-body point absorber (2BPA) and an oscillating surge wave energy converter (OSWEC). The first aim is to mesh the bodies of the earlier mentioned WECs to calculate their hydrostatic properties using axiMesh.m and Mesh.m functions provided by NEMOH. The second aim is to calculate the first-order hydrodynamic coefficients of the WECs using the NEMOH BEM solver and to study the ability of this method to eliminate irregular frequencies. The third is to generate a *.h5 file for 2BPA and OSWEC devices, in which all the hydrodynamic data are included. The BEMIO, a pre-and post-processing tool developed by WEC-Sim, is used in this study to create *.h5 files. The primary and final goal is to run the wave energy converter Simulator (WEC-Sim) to simulate the dynamic responses of WECs studied in this thesis and estimate their power performance at different sites located in the Mediterranean Sea and the North Sea. The hydrodynamic data obtained by the NEMOH BEM solver for the 2BPA and OSWEC devices studied in this thesis is imported to WEC-Sim using BEMIO. Lastly, the power matrices and annual energy production (AEP) of WECs are estimated for different sites located in the Sea of Sicily, Sea of Sardinia, Adriatic Sea, Tyrrhenian Sea, and the North Sea. To this end, the NEMOH and WEC-Sim are still the most practical tools to estimate the power generation of WECs numerically

    Management of gastrointestinal complaints in differentiated thyroid cancer patients treated with

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    Comparison of the efficacy of pantoprazole, metoclopramide, and ondansetron – a randomized clinical tria

    Radioactive Iodine Therapy and Glucose Tolerance

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    Radioactive iodine therapy is commonly used as an adjuvant therapy in follicular and papillary thyroid carcinoma (PTC) and in the treatment of Graves’ disease (GD). The basis of this therapy is the accumulation of radioactive iodine by the sodium-iodide symporter (NIS) in the thyroid gland. Expression of NIS by extrathyroidal tissues such as islets of pancreas has been reported. Radioactive iodine uptake by pancreatic beta-cells can potentially damage these cells. In this study, we discuss the possible associations between radioactive iodine and glucose intolerance. Overall, radioactive iodine uptake by the pancreas may damage beta-cells and predispose patients to glucose intolerance or type 2 diabetes, particularly in patients exposed to radioactive iodine therapy following total thyroidectomy. Further studies are needed to clarify and confirm this association
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