805 research outputs found

    Mechanical and Electrical Design Calculations of Hybrid Vehicles

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    Electric power is widely used in electric traction for many reasons: it is easy to control the speed of an electric motor, the absence of exhaust gases, free of noise, it has high starting torque, and it needs less maintenance than its mechanical counterpart. In the current research, a modern hybrid car is designed and manufactured in three ways. The first method is using a 220 volt AC electric power to charge five series batteries; each battery has 12 VDC (35 A/h) to supply totally 60 VDC input voltage for the electronic inverter which converts 60 VDC to 60 VAC (three-phase voltage) as a controllable voltage source to three-phase synchronous motor (SM) type (BLDC-YG1-ZZ-1200 W). The second method is to take advantage of the solar energy which is almost available in Iraq environment throughout the year to be stored in the batteries, especially during the shutdown of the machine and when it stops it under the sun. The solar panel is fixed on the vehicle’s roof; it has a power of 100 watts. The third method is the mechanical energy by using the bicycle pedal to move the wheels of the car; it is useful in the event of a sudden interruption of electrical power or a technical failure in the vehicle. In addition, three kinds of electronic devices are used for control. The first control is electric battery charger. The second control is to convert solar radiation into electrical energy to be stored in the batteries. The third control is to regulate the accessories of another electric vehicle. The vehicle was tested in the province of Diyala, Baquba, Iraq, on a flat and tilted land (Al Mafraq Bridge, Baquba city). The steady-state speed reached more than 40 km/h with a total load of more than 125 kg. The design is subjected to real electrical and mechanical engineering tests alongside using decades of applied equations on locomotives and electric vehicles to validate the experimental tests

    Antimalarial Activity of Certain Sudanese Medicinal Plants Used in Folk –Medicine

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    Ten indigenous plants of common use in Sudanese folk-medicine, vitro for antimalarial activity against Plasmoclium were examined in falciparum, the major human malaria parasite. All plant samples displayed various antimalarial activity. Three plant extracts caused 100% inhibition of the parasite growth at a concentration ≤ 500 g/ml. The most active extracts that produced 100% inhibition of the parasite growth at a concentration ≤ 50 g/ml were obtained from the seeds of Nigella sativa and the whole plant of Aristolochia bracteolata. These two plants were phytochemically screened for their active constituents and both showed the presence of sterols, alkaloids and tannins

    Model predictive control of magnetic levitation system

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    In this work, we suggest a technique of controller design that applied to systems based on nonlinear. We inform the sufficient conditions for the stability of closed loop system. The asymptotic stability of equilibrium and the nonlinear controller can be applied to improvement the stability of Magnetic Levitation system(MagLev). The MagLev nonlinear nodel can be obtained by state equation based on Lagrange function and Model Predictive Control has been used for MagLev system

    Antiplasmodial Activity of Some Medicinal Plants Used in Sudanese Folk-medicine

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    Ten plants indigenous to Sudan and of common use in Sudanese folk-medicine, were examined in vitro for antimalarial activity against schizonts maturation of Plasmodium falciparum, the major human malaria parasite. All plant samples displayed various antiplasmodial activity. Three plant extracts caused 100% inhibition of the parasite growth at concentrations of plant material ≤ 500 ug/ml. The two most active extracts that produced 100% inhibition of the parasite growth at concentration of plant material ≤ 50 μg/ml were obtained from the seeds of Nigella sativa and the whole plant of Aristolochia bracteolata. The ten plants were phytochemically screened for their active constituents. The two most active plants showed the presence of sterols, alkaloids and tannins

    Menopause Awareness, Symptoms Assessment and Menqol Among Bahrain Women

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    Menopause is a normal physiological process of the permanent cessation of ovarian hormone reproduction, thereby offending the regular menstrual cycle. Critical period in women’s life occurs 40 to 60 years. Frequently reported symptoms are physiological disturbances, psychological complaints including mood swings and& other changes that may impair the overall quality of life. Menopausal symptoms significantly reduce the Quality of Life (QOL) and further worsens with more severity of the condition. The aim of this study was to assess the menopausal awareness and related symptoms that affects the quality of life. Methods: A cross-sectional community survey design was adopted among 128 women through convenience sampling by using Menopause awareness scale and MenQol. Results: The domain-wise prevalence of symptoms score on vasomotor was 51.5%(66), psychosocial 35.2%(45), 44.5%(57), sexual 25.8%(33) and others 44.5%(57). Overall score was 40.6%(52). In relation to menopause awareness, low 7.8 % (10), Moderate 82.0% (105) and high 10.2%(13).Conclusion: Menopause awareness programs need to be initiated at the community level for better health and the Quality of Life. Keywords: Menopause, Bahraini women, Menopause related QOL, Awarenes

    Antimicrobial modification of PLA scaffolds with ascorbic and fumaric acids via plasma treatment

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    An optimal medical scaffold should be biocompatible and biodegradable and should have adequate mechanical properties and scaffold architecture porosity, a precise three-dimensional shape, and a reasonable manufacturing method. Polylactic acid (PLA) is a natural biodegradable thermoplastic aliphatic polyester that can be fabricated into nanofiber structures through many techniques, and electrospinning is one of the most widely used methods. Medical fiber mat scaffolds have been associated with inflammation and infection and, in some cases, have resulted in tissue degradation. Therefore, surface modification with antimicrobial agents represents a suitable solution if the mechanical properties of the fiber mats are not affected. In this study, the surfaces of electrospun PLA fiber mats were modified with naturally occurring L-ascorbic acid (ASA) or fumaric acid (FA) via a plasma treatment method. It was found that 30 s of radio-frequency (RF) plasma treatment was effective enough for the wettability enhancement and hydroperoxide formation needed for subsequent grafting reactions with antimicrobial agents upon their decomposition. This modification led to changes in the surface properties of the PLA fiber mats, which were analyzed by various spectroscopic and microscopic techniques. FTIR-ATR confirmed the chemical composition changes after the modification process and the surface morphology/topography changes were proven by SEM and AFM. Moreover, nanomechanical changes of prepared PLA fiber mats were investigated by AFM using amplitude modulation-frequency modulation (AM-FM) technique. A significant enhancement in antimicrobial activity of such modified PLA fiber mats against gram-positive Staphylococcus aureus and gram-negative Escherichia coli are demonstrated herein. © 2020 The AuthorsQatar National Research Fund (a member of The Qatar Foundation) [22-076-1-011]; Qatar University Collaborative Grant [QUCG-CAM-20/21-3]; Czech Science FoundationGrant Agency of the Czech Republic [19-16861S

    Histopathologic predictors of survival and recurrence in resected ampullary adenocarcinoma

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    Objective: The aim of the study was to define histopathologic characteristics that independently predict overall survival (OS) and disease-free survival (DFS), in patients who underwent resection of an ampullary adenocarcinoma with curative intent. Summary Background Data: A broad range of survival rates have been described for adenocarcinoma of the ampulla of Vater, presumably due to morphological heterogeneity which is a result of the different epitheliums ampullary adenocarcinoma can arise from (intestinal or pancreaticobiliary). Large series with homogenous patient selection are scarce. Methods: A retrospective multicenter cohort analysis of patients who underwent pancreatoduodenectomy for ampullary adenocarcinoma in 9 European tertiary referral centers between February 2006 and December 2017 was performed. Collected data included demographics, histopathologic details, survival, and recurrence. OS and DFS analyses were performed using Kaplan–Meier curves and Cox proportional hazard models. Results: Overall, 887 patients were included, with a mean age of 66 ± 10 years. The median OS was 64 months with 1-, 3-, 5-, and 10-year OS rates of 89%, 63%, 52%, and 37%, respectively. Histopathologic subtype, differentiation grade, lymphovascular invasion, perineural invasion, T-stage, N-stage, resection margin, and adjuvant chemotherapy were correlated with OS and DFS. N-stage (HR = 3.30 [2.09–5.21]), perineural invasion (HR = 1.50 [1.01–2.23]), and adjuvant chemotherapy (HR = 0.69 [0.48–0.97]) were independent predictors of OS in multivariable analysis, whereas DFS was only adversely predicted by N-stage (HR = 2.65 [1.65–4.27]). Conclusions: Independent predictors of OS in resected ampullary cancer were N-stage, perineural invasion, and adjuvant chemotherapy. N-stage was the only predictor of DFS. These findings improve predicting survival and recurrence after resection of ampullary adenocarcinoma

    Influence of Adiposity-Related Genetic Markers in a Population of Saudi Arabians Where Other Variables Influencing Obesity May Be Reduced

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    Large scale studies in Europeans have clearly identified common polymorphism affecting BMI and obesity. We undertook a genotype study to examine the impact of variants, known to influence obesity, in a sample from the Saudi Arabian population, notable for its profound combination of low mean physical activity indices and high energy intake. Anthropometry measures and genotypes were obtained for 367 Saudis, taken from King Saud University and Biomarker Screening Project in Riyadh (Riyadh Cohort). We observed large effect sizes with obesity for rs10767664 (BDNF) (OR = 1.923, P=0.00072) and rs3751812 (FTO) (OR = 1.523, P=0.016) in our sample and, using weighted genetic risk scores, we found strong evidence of a cumulative effect using 11 SNPs taken predominantly from loci principally affecting appetite (OR = 2.57, P=0.00092). We used conditional analyses to discern which of our three highly correlated FTO SNPs were responsible for the observed signal, although we were unable to determine with confidence which best marked the causal site. Our analysis indicates that markers located in loci known to influence fat mass through increased appetite affect obesity in Saudi Arabians to an extent possibly greater than in Europeans. Larger scale studies will be necessary to obtain a precise comparison

    The prevalence and clinical characteristics of nonradiographic axial spondyloarthritis among patients with inflammatory back pain in rheumatology practices: a multinational, multicenter study

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    BACKGROUND: Patients with ankylosing spondylitis (AS), who by definition have radiographic sacroiliitis, typically experience symptoms for a decade or more before being diagnosed. Yet, even patients without radiographic sacroiliitis (i.e., nonradiographic axial spondyloarthritis [nr-axSpA]) report a significant disease burden. The primary objective of this study was to estimate the prevalence and clinical characteristics of nr-axSpA among patients with inflammatory back pain (IBP) in rheumatology clinics in a number of countries across the world. A secondary objective was to estimate the prevalence of IBP among patients with chronic low back pain (CLBP). METHODS: Data were collected from 51 rheumatology outpatient clinics in 19 countries in Latin America, Africa, Europe, and Asia. As consecutive patients with CLBP (N = 2517) were seen by physicians at the sites, their clinical histories were evaluated to determine whether they met the new Assessment of SpondyloArthritis international Society criteria for IBP. For those who did, their available clinical history (e.g., family history, C-reactive protein [CRP] levels) was documented in a case report form to establish whether they met criteria for nr-axSpA, AS, or other IBP. Patients diagnosed with nr-axSpA or AS completed patient-reported outcome measures to assess disease activity and functional limitations. RESULTS: A total of 2517 patients with CLBP were identified across all sites. Of these, 974 (38.70 %) fulfilled the criteria for IBP. Among IBP patients, 29.10 % met criteria for nr-axSpA, and 53.72 % met criteria for AS. The prevalence of nr-axSpA varied significantly by region (p < 0.05), with the highest prevalence reported in Asia (36.46 %) and the lowest reported in Africa (16.02 %). Patients with nr-axSpA reported mean ± SD Ankylosing Spondylitis Disease Activity Scores based on erythrocyte sedimentation rate and CRP of 2.62 ± 1.17 and 2.52 ± 1.21, respectively, indicating high levels of disease activity (patients with AS reported corresponding scores of 2.97 ± 1.13 and 2.93 ± 1.18). Similarly, the overall Bath Ankylosing Spondylitis Disease Activity Index score of 4.03 ± 2.23 for patients with nr-axSpA (4.56 ± 2.17 for patients with AS) suggested suboptimal disease control. CONCLUSIONS: These results suggest that, in the centers that participated in the study, 29 % of patients with IBP met the criteria for nr-axSpA and 39 % of patients with CLBP had IBP. The disease burden in nr-axSpA is substantial and similar to that of AS, with both groups of patients experiencing inadequate disease control. These findings suggest the need for early detection of nr-axSpA and initiation of available treatment options to slow disease progression and improve patient well-being

    Central versus Peripheral Postcardiotomy Veno-Arterial Extracorporeal Membrane Oxygenation: Systematic Review and Individual Patient Data Meta-Analysis

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    Background: It is unclear whether peripheral arterial cannulation is superior to central arterial cannulation for postcardiotomy veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Methods: A systematic review was conducted using PubMed, Scopus, and Google Scholar to identify studies on postcardiotomy VA-ECMO for the present individual patient data (IPD) meta-analysis. Analysis was performed according to the intention-to-treat principle. Results: The investigators of 10 studies agreed to participate in the present IPD meta-analysis. Overall, 1269 patients were included in the analysis. Crude rates of in-hospital mortality after central versus peripheral arterial cannulation for VA-ECMO were 70.7% vs. 63.7%, respectively (adjusted OR 1.38, 95% CI 1.08–1.75). Propensity score matching yielded 538 pairs of patients with balanced baseline characteristics and operative variables. Among these matched cohorts, central arterial cannulation VA-ECMO was associated with significantly higher in-hospital mortality compared to peripheral arterial cannulation VA-ECMO (64.5% vs. 70.8%, p = 0.027). These findings were confirmed by aggregate data meta-analysis, which showed that central arterial cannulation was associated with an increased risk of in-hospital mortality compared to peripheral arterial cannulation (OR 1.35, 95% CI 1.04–1.76, I2 21%). Conclusions: Among patients requiring postcardiotomy VA-ECMO, central arterial cannulation was associated with an increased risk of in-hospital mortality compared to peripheral arterial cannulation. This increased risk is of limited magnitude, and further studies are needed to confirm the present findings and to identify the mechanisms underlying the potential beneficial effects of peripheral VA-ECMO
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