699 research outputs found

    Chemotherapy Induced Cardiomyopathy: Pathogenesis, Monitoring and Management

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    The survival rate of cancer patients has greatly increased over the last 20 years. However, to achieve this result, a considerable price has been paid in terms of the side effects associated with the intensive anticancer treatment. The most common adverse effect is cardiotoxicity which may compromise the clinical effectiveness of chemotherapy, affecting the patient's survival and quality of life independently of the oncological prognosis. There are 2 types of cardiac toxicities, type I which is more serious and result in permanent damage to the myocardium and type II which is usually reversible. Chemotherapies varies in their incidence of inducing cardiomyopathy, and the onset which may occur acutely (during or shortly after treatment), sub-acutely (within days or weeks after completion of chemotherapy) or chronically (weeks to months after drug administration). Cardiac events associated with chemotherapy may consist of mild blood pressure changes, thrombosis, Electrocardiographic (ECG) changes, arrhythmias, myocarditis, pericarditis, myocardial infarction, cardiomyopathy, cardiac failure (left ventricular failure), and congestive heart failure (CHF). The risk for such effects depends upon: cumulative dose, rate of drug administration, mediastinal radiation, advanced age, younger age, female gender, pre-existing heart disease and hypertension. Serial measurements of LVEF and fractional shortening are the most common indices monitored to assess left ventricular systolic function and cardiotoxicity. This can be achieved by 2-dimensional, M-mode and color Doppler echocardiographic examination; also Cardiac troponins as a biological marker for myocardial damage can be used for monitoring in patients received anthracyclines. Angiotensin-converting enzyme (ACE) inhibitors (ACEIs) have been shown to slow the progression of left ventricular dysfunction in several different clinical settings, including anthracycline-induced cardiomyopathy. Carvedilol and probably with anti-oxidants like Probucol and vitamin E benefits also

    Enhancing the performance of precast hybrid concrete deep beams using curved and arched designs : experimental investigations

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    In recent years, deep beam performance improvement has garnered significant interest, leading to several proposed solutions. This study introduces and compares two new models of hybrid concrete deep beams, aiming to outperform conventional designs. Nine experimental specimens were subjected to one-point and two-point static loadings. The specimens shared identical dimensions, with an overall span of 1700 mm, width of 180 mm, and overall depth of 450 mm. Response parameters such as cracking and failure loads, failure modes, crack propagation rates, toughness, stiffness, and ductility were evaluated. Results indicated substantial enhancements compared to the conventional hybrid model. The curved model achieved a 5 % and 12 % increase in failure load under one-point and two-point loading, respectively. The corresponding enhancements for the arched model were 13 % and 20 %. Notably, toughness improvements ranged from 32 to 39 % and 97 % under two-point loading for the curved and arched models, respectively. Ductility gains were 39 % and 45 % under two-point loading and (45–57)% and 74 % under one-point loading for the respective models. The findings highlight the potential of the curved model with reactive powder concrete-normal strength concrete (RN) composition, offering increased load-carrying capacity and the possibility of using low-strength concrete for cost and weight reduction. The arched model also demonstrated significant enhancements. Changing the loading configuration from two-point to one-point resulted in reduced capacity, but the proposed models mitigated this reduction. This study contributes valuable insights into the behaviour of precast hybrid concrete deep beams, showcasing the superior performance of the proposed curved and arched models

    miR-135a targets IRS2 and regulates insulin signaling and glucose uptake in the diabetic gastrocnemius skeletal muscle

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    AbstractAlthough aberrant miRNA signatures are associated with diabetes, yet, the status and role of altered miRNAs in the diabetic skeletal muscle is currently poorly understood. Here, we report that 41 miRNAs are altered in the diabetic gastrocnemius skeletal muscle and of these, miR-135a that is identified as a critical regulator of myogenesis, is significantly up-regulated. IRS2 is predicted as its potential putative target and its levels are down-regulated in the diabetic gastrocnemius skeletal muscle. In C2C12 cells, while miR-135a levels decreased during differentiation, IRS2 levels were up-regulated. miR-135a significantly reduced IRS2 protein levels and its 3′UTR luciferase reporter activity and these were blunted by the miR-135a inhibitor and mutation in the miR-135a binding site. Knock-down of endogenous miR-135a levels increased IRS2 at the mRNA and protein levels. miR-135a also attenuated insulin stimulated phosphorylation and activation of PI3Kp85α and Akt and glucose uptake. miR-135a levels were also found to be elevated in the human diabetic skeletal muscle. In-vivo silencing of miR-135a alleviated hyperglycemia, improved glucose tolerance and significantly restored the levels of IRS2 and p-Akt in the gastrocnemius skeletal muscle of db/db mice without any effect on their hepatic levels. These suggest that miR-135a targets IRS2 levels by binding to its 3′UTR and this interaction regulates skeletal muscle insulin signaling

    Simulation-based Study of Capacitance Values Affected by Various Dielectric Materials and Distances for Low Power Wireless Power Transfer System

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    Capacitive Power Transfer (CPT) system is nowadays getting better attention by some of the researchers who are focusing on wireless power transfer field. This is because of the simplicity, small size, and better reaction towards EMI characteristics of the method. Furthermore, the efficiency of the CPT system is greatly influenced by the coupling capacitances which are varied by distances and permittivity values. Thus, this paper attempts to converge into the effect of several dielectric materials towards capacitance values and also the effect of the capacitive plates’ distances towards the output power. By using Class E circuit configuration and MATLAB Simulink as the simulation software, the results are then explained graphically. From those simulations, the work achieved 90.7% as highest efficiency as compared to the theoretical values

    Effect of Friction Stir Welding Parameters on the Mechanical Properties ‎of Dissimilar Polymer Joints

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    تتطلب وصلات اللحام من المواد التي يصعب لحامها بالطرق التقليدية، وخاصة المواد البوليميرية، لحام الخلط الاحتكاكيFSW) ). في هذا البحث تم استخدام نوعين من البوليمرات لدراسة تأثير بعض عوامل اللحام الاحتكاك) على الخواص الميكانيكية لوصلات لحام البوليمرات الغير متشابهة. تم لحام ألواح البولي إيثيلين عالي الكثافة HDPE) ) والبولي فينيل كلورايد PVC) ) بأبعاد (5 × 100 × 200 مم) باستخدام تقنية الخلط الاحتكاكي (FSW). تم استخدام اداة اللحام بقطر الكتف (18 مم) وقطر المسمار (6 مم) بارتفاع (4.8 مم). تم استخدام السرع الدورانية (340, 495, 675, 850, 1660 دورة في الدقيقة) مع سرعتين خطية (24 , 40 مم / ثانية). أظهرت نتائج الاختبارات الميكانيكية زيادة الصلابة مع زيادة سرعة الدوران حتى (850 دورة في الدقيقة) ثم انخفضت عند سرعة اللحام الخطية (24 مم / ثانية). وكذلك انخفضت قيمة الصلابة عند السرعة الخطية (40 مم / ثانية). بالإضافة إلى ذلك تم الحصول على أقصى صلادة ومقاومة شد عند السرعة الدورانية والخطية (495 دورة في الدقيقة)، (24 مم / ثانية) على التوالي، حيث كانت اقصى صلابة (72 شور د) ومقاومة شد (39 ميجا باسكال). أخيرًا، أظهرت النتائج بنجاح هذه التقنية من اللحام في لحام المواد البوليميرية الغير متشابهة.Welding joints of materials that are difficult to weld with traditional methods, particularly polymeric materials, require friction stir welding (FSW). In this research, two types of polymers have been used to study the effect of friction stir welding (FSW) parameters on the properties of dissimilar polymer joints. High density polyethylene (HDPE) and polyvinyl chloride (PVC) plates with dimension of (5x100x200 mm) were welded by using milling machine as friction stir welding machine. The welding tool was used with shoulder diameter of (18 mm) and pin diameter of (6 mm) with height of (4.8 mm). The rotation speed was applied in the range of (340 to 1660 rpm) with welding linear speed of (24 and 40 mm/sec). The result shows that the hardness was increased with increasing rotational speed until (850 rpm) then decreased when the welding speed equal to (24 mm/sec).  However, its decreased with increasing welding linear speed when it became (40 mm/sec). In addition, the maximum hardness and tensile strength was found at rotational speed equal to (495 rpm) and welding linear speed equal to (24 mm/sec) which equal to hardness of (72 Shore D) and tensile strength of (39 MPa). Finally, the result displays that there is an opportunity to weld dissimilar polymers

    VICINE AND CONVICINE LEVELS IN DRY AND FRESH BEANS DURING THE GROWTH STAGES AND THE EFFECT OF ENZYMATIC TREATMENT AND PROCESSING CONDITIONS ON THEIR REMOVAL.

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    Beans (Vicia faba) contain some anti-nutritional compounds, especially vicine and convicine and their non-sugar derivatives, divicine and isouramil, which are responsible for the occurrence of Favism in people with hereditary deficiency of Glucose-6-phosphate dehydrogenase (G6PD). These study objective was estimation of vicine and convicine content and their distribution in dry and green bean parts during the growth stages, and the effect of beta-glucosidase from defatted apricot seed powder and some home-based processing conditions on elimination of these compounds from the bean. The results showed that the content of vicine & convicine in bean ranged from 22.7 mg/100 g in the seedling stage to 46.8 mg/100 g in the pods stage at 139 days. As for vicine, it ranged from 12.6 mg /100g to 29 mg/100g at the above stages respectively. While for convicine it ranged from 10.1 mg/100g to 17.8 mg/100 respectively. The enzymatic treatments showed significant elimination of those compounds as compared to non-enzymatic treatments. Additionally, other factors such as soaking temperature, pH, and time as well as cooking process had a positive effect on the elimination of those glucosides

    dosimetric studies of mixed energy intensity modulated radiation therapy for prostate cancer treatments

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    Dosimetric studies of mixed field photon beam intensity modulated radiation therapy (IMRT) for prostate cancer using pencil beam (PB) and collapsed cone convolution (CCC) algorithms using Oncentra MasterPlan treatment planning system (v. 4.3) are investigated in this study. Three different plans were generated using 6 MV, 15 MV, and mixed beam (both 6 and 15 MV). Fifteen patients with two sets of plans were generated: one by using PB and the other by using CCC for the same planning parameters and constraints except the beam energy. For each patient's plan of high energy photons, one set of photoneutron measurements using solid state neutron track detector (SSNTD) was taken for this study. Mean percentage ofV66 Gyin the rectum is18.55±2.8,14.58±2.1, and16.77±4.7for 6 MV, 15 MV, and mixed-energy plans, respectively. Mean percentage ofV66 Gyin bladder is16.54±2.1,17.42±2.1,and16.94±41.9for 6 MV, 15 MV, and mixed-energy plans, respectively. Mixed fields neutron contribution at the beam entrance surface is 45.62% less than at 15 MV photon beam. Our result shows that, with negligible neutron contributions, mixed field IMRT has considerable dosimetric advantage

    Experimental Nonlinear Control for Flutter Suppression in a Nonlinear Aeroelastic System

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    Experimental implementation of input–output feedback linearization in controlling the dynamics of a nonlinear pitch–plunge aeroelastic system is presented. The control objective is to linearize the system dynamics and assign the poles of the pitch mode of the resulting linear system. The implementation 1) addresses experimentally the general case where feedback linearization-based control is applied using as the output a degree of freedom other than that where the physical nonlinearity is located, using a single trailing-edge control surface, to stabilize the entire system; 2) includes the unsteady effects of the airfoil’s aerodynamic behavior; 3) includes the embedding of a tuned numerical model of the aeroelastic system into the control scheme in real time; and 4) uses pole placement as the linear control objective, providing the user with flexibility in determining the nature of the controlled response. When implemented experimentally, the controller is capable of not only delaying the onset of limit-cycle oscillation but also successfully eliminating a previously established limit-cycle oscillation. The assignment of higher levels of damping results in notable reductions in limit-cycle oscillation decay times in the closed-loop response, indicating good controllability of the aeroelastic system and effectiveness of the pole-placement objective. The closed-loop response is further improved by incorporating adaptation so that assumed system parameters are updated with time. The use of an optimum adaptation parameter results in reduced response decay times

    EXTRACTION, PURIFICATION AND CHARACTERIZATION OF ELASTASE FROM THE DIGESTIVE DUCT OF CATFISH (SILURUS TRIOSTEGUS)

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    This study was aimed to extract, purify and characterize the pancreatic elastase from the Catfish (silurus trioseegus) digestive duct. Different extraction solutions were used to optimize the extraction condition being (Distilled water, 200 mM NaCl, Phosphate buffer (100 mM, pH 8), the latter buffer Tis-HCl (100 mM, pH 8) both  containing 0-100 mM NaCl or CaCl2 separately). Tris-HCl buffer containing 100 mM CaCl2 was the best among the rest extraction solutions. The crude extract was precipitated using a 30 % - 55 % of ammonium sulfate saturation ratio. The crude precipitate was dissolved in the same buffer and dialyzed. Then the dialyzed precipitate was concentrated and applied to CM-52 column (3.5 ×10 cm), elastase activity was appeared in two protein peaks. Each peak fraction were pooled individually and loaded on a Sephadex G-75 column (1.6×62 cm). Elastase activity was recovered only from one peak with 29.54 % yield, 530.70 U total activity and 17.89 U/mg specific activity. The optimum temperature for elastase stability and activity was 0-30 C° and 55 C° respectively. while the optimum pH for the enzyme activity and stability were 9 and 4-9 respectively. The molecular weight was 21898 Da as determined by Gel filtration
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