176 research outputs found

    Analysis of Wind Turbine Driven Permanent Magnet Synchronous Generator under Different Loading Conditions

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    This paper proposes the configuration of a Wind Turbine generating system equipped with Permanent Magnet Synchronous Generator (PMSG). There are different types of synchronous generators, but the PMSG is chosen which has better performance due to higher efficiency and less maintenance. Since it can be used without a gearbox also implies a reduction of the weight of the nacelle and a reduction of costs. The model includes a wind turbine model, drive train model and PMSG model. The equations that explain their behavior have been introduced. The generator model is established in the d-q synchronous rotating reference frame. The proposed Wind Turbine Generator System (WTGS) has been implemented in MATLAB/SIMULINK software. The PMSG is operating in stand-alone which is loaded with different types of loads. The simulation results indicate the ability of wind driven PMSG to operate over wide range of operating conditions at different loading conditions and show effect of different load types in operation. Keywords: Permanent Magnet Synchronous Generator (PMSG), Wind Turbine, Wind Energy and WTGS MATLAB/SIMULINK

    Magnesium in type 2 diabetes mellitus and its correlation with glycemic control

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    Background: Hypomagnesaemia may have negative impact on glucose homeostasis and insulin sensitivity. This study was done to compare serum Mg levels in type 2 diabetic patients with non diabetic healthy control subjects and to assess the correlation between serum Mg levels and glycemic control in Egyptian patients.Methods: 60 type 2 diabetic patients attending the outpatient clinic of diabetes at Kasr Al Aini hospital faculty of medicine Cairo University and 30 healthy age matched control subjects were enrolled. Fasting blood sugar, fasting insulin, fasting lipids, Hb A1C and serum Mg were measured. Weight, height and blood pressure were recorded. BMI, IR (HOMA), were calculated. The data was analyzed and expressed in terms of mean ± SD. Pearson correlation was performed to establish the relationship between Mg and metabolic variables in type 2 diabetic patients.Results: serum Mg levels were significantly reduced in type 2 diabetic patients compared to the control group with mean ±SD (1.29 ± 0.31 mg/dl) versus (2.41 ± 0.13 mg/dl) with P value < 0.001. There were highly significantly negative correlations between serum Mg levels and HbA1c, fasting glucose and insulin resistance with (r = -0.969, -0.894, -0.653) respectively, P value < 0.001. The best cut off point of Mg was ≤ 2.0 mg/dl in differentiating cases from controls using ROC curve analysis.Conclusion: hypomagnesaemia is closely linked to type 2 diabetes mellitus and it is strongly correlated to glycemic control. We recommend to measure serum Mg in type 2 diabetes and patients who need supplementation should be considered.

    Cisplatin augments the anti-schistosomal effect of praziquantel in a schistosoma-infected cancer model

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    Schistosomiasis is the third most devastating tropical disease worldwide caused by blood flukes of the genus Schistosoma. Praziquantel (PZQ) is the drug of choice for treating all species of schistosomes. However, PZQ kills only adult Schistosoma worms, not immature stages. The inability of PZQ to abort early infection or prevent re-infection, and the lack of prophylactic effect prompt the need for novel drugs and strategies for the prevention of schistosomiasis. Tumor burden can be developed in Schistosoma-infected patients. The present study aimed to determine the host responses to mutual interaction between cancer, represented by Ehrlich ascites, and infection, represented by Schistosomiasis. Mice infected with Schistosoma and challenged with tumor 4-5 weeks later showed the same anti-schistosomal (worm and egg burden) and antitumor (total tumor cell count and mouse survival) parameters when compared to mice infected with Schistosoma alone or challenged with tumor cells alone. As expected, combinatorial treatment with PZQ and cisplatin of Schistosoma-infected mice that were challenged with tumor cell line decreased the tumor burden as well as the worm and egg burden after treatment as compared to the non-treated controls; while the worm burden and egg counts were significantly decreased (P &lt;0.001) in treated group (VI) treated with cisplatin (0.5 mg/kg), group (VII) treated with cisplatin (2 mg/kg), group (VIII) treated with PZQ/ cisplatin (0.5 mg/kg) and group (IX) treated with PZQ / cisplatin (2 mg/kg) by 44.55% , 74%, 100% and 97.8% in worm burden, and by 47%, 78.7%, 96% and 97% in liver egg count , respectively than that of group (II) non treated S. mansoni infected alone and (IV) non treated S. mansoni/EAC alone. Also, Group IX caused a significant reduction (P &lt;0.05) in worm burden than that of group VI. Also, total ascetic volume and the tumor cell counts in Ehrlich's ascites carcinoma (EAC)-cells were significantly decreased (P &lt;0.001) in groups VIII and IX than that of the group (III) non-treated (EAC) inoculated alone. There was no mutual interaction between schistosomiasis infection and tumor burden. Also, whereas, PZQ did not affect on the antitumor parameters, cisplatin even at low doses had anti-schistosomal effects

    A Parabolic Transform and Averaging Methods for General Partial Differential Equations

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    Averaging method of the fractional general partial differential equations and a special case of these equations are studied, without any restrictions on the characteristic forms of the partial differential operators. We use the parabolic transform, existence and stability results can be obtained

    Effects of suramin on hormone release by cultured rat anterior pituitary cells

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    Abstract Suramin is a polyanionic compound which has been used in the treatment of trypanosomiasis and acquired immunodeficiency syndrome (AIDS), while preliminary success h

    Longitudinal changes in peri-papillary retinal nerve fiber layer thickness in patients with unilateral branch retinal vein occlusion

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    Background: Associations between retinal venous occlusion (RVO), elevated intraocular pressure, and glaucoma have been reported. Further investigations into structural alterations in the fellow eyes of individuals with unilateral RVO have revealed that the peripapillary retinal nerve fiber layer is thinner than in healthy eyes, suggesting that there may be systemic risk factors common to both RVO and glaucoma. We aimed to evaluate changes in peripapillary retinal nerve fiber layer thickness (pRNFLT) among individuals with unilateral branch retinal vein occlusion (BRVO). Methods: This prospective observational study recruited 30 individuals (60 eyes) with newly diagnosed unilateral BRVO and macular edema, and a control group of 30 healthy individuals (30 eyes) with no abnormalities on fundus examination or concurrent systemic comorbidities. After baseline measurements, the participants were reassessed at 6, 12, and 24 months by measuring global and sectoral pRNFLT using spectral-domain optical coherence tomography. Results: The mean age and sex distributions were comparable between the patient and control groups (both P &gt; 0.05). When compared to fellow eyes, global and sectoral pRNFLT in eyes with BRVO were significantly higher at baseline (all P &lt; 0.05). Over time, pRNFLT decreased dramatically, and by the conclusion of the two-year follow-up, there was a significant reduction from baseline in the affected eyes (all P &lt; 0.05). Likewise, affected eyes experienced a significant improvement in best-corrected distance visual acuity and central macular thickness over the two-year follow-up (both P Less than or equal to 0.001). Comparing the global and all-sector pRNFLT of fellow eyes in the patient group with those of normal eyes in the control group, there were no significant differences at any visit, except in the temporal sector, which revealed a significant reduction in pRNFLT at 24 months in the fellow eyes of patients with unilateral BRVO (P = 0.02).&nbsp;&nbsp; Conclusions: Patients with unilateral BRVO experienced a significant reduction in pRNFLT in the affected eyes and, to a lesser extent, in the fellow eyes, compared with that of the control arm, suggesting that they are prone to retinal nerve fiber layer damage. The reduction in pRNFLT in the normal fellow eyes of patients with BRVO may be attributed to age or concurrent systemic comorbidities. Further studies with long follow-up periods are required to shed light on the etiology of functional and structural changes in both the retinal nerve fiber layer and ganglion cell complex in the normal and affected eyes of patients with unilateral BRVO

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

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    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London
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