A digital controller for a unity power factor converter

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1993.Includes bibliographical references (leaves 153-154).by Ahmed Mitwalli.M.S

Non-Communicable Disease Risk Factors among Employees and Their Families of a Saudi University: An Epidemiological Study

Objectives:To assess the prevalence of non-communicable disease (NCD) risk factors among Saudi university employees and their families; to estimate the cardiovascular risk (CVR) amongst the study population in the following 10years. Methods:The NCD risk factors prevalence was estimated using a cross-sectional approach for a sample of employees and their families aged ≥ 18 years old, in a Saudi university (Riyadh in Kingdom of Saudi Arabia; KSA). WHO STEPwise standardized tools were used to estimate NCD risk factors and the Framingham Coronary Heart Risk Score calculator was used to calculate the CVR. Results:Five thousand and two hundred subjects were invited, of whom 4,500 participated in the study, providing a response rate of 87%. The mean age of participants was 39.3±13.4 years. The majority of participants reported low fruit/vegetables consumption (88%), and physically inactive (77%). More than two thirds of the cohort was found to be either overweight or obese (72%), where 36% were obese, and 59% had abdominal obesity. Of the total cohort, 22–37% were found to suffer from dyslipidaemia, 22% either diabetes or hypertension, with rather low reported current tobacco use (12%). One quarter of participants was estimated to have >10% risk to develop cardiovascular disease within the following 10-years. Conclusion:The prevalence of NCD risk factors was found to be substantially high among the university employees and their families in this study

African Linguistics in Central and Eastern Europe, and in the Nordic Countries

Non peer reviewe

Polymer gel actuators and sensors

Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.Includes bibliographical references (p. [351]-361).by Ahmed Hamdi Mitwalli.Sc.D

Why are serum magnesium levels lower in Saudi dialysis patients?

أهداف البحث: غالبا ما يتغير مستوى المغنيسيوم في الدم عند مرضى غسيل الكلى. أجريت هذه الدراسة للتأكد من اختلاف مستويات المغنسيوم عند المرضى الذين يعالجون بغسيل الكلى. طرق البحث: أجريت هذه الدراسة الاستعادية في وحدة غسيل الكلى بمستشفى الملك خالد الجامعي٬ جامعة الملك سعود بالرياض٬ على المرضى الذين يخضعون لغسيل الكلى بانتظام. تم توثيق البيانات الديموغرافية للمرضى٬ بما فيها مؤشر كتلة الجسم٬ ومستوى الكالسيوم بالدم٬ والمغنيسيوم٬ وهرمون الغدة الجار درقية٬ والكوليسترول٬ والدهون الثلاثية. النتائج: من بين ما مجموعه ١١٥ مريضا٬٧٠ (٦٠.٩٪) كانوا على غسيل الكلى الدموي و ٤٥ (٣٩.١٪) على غسيل الكلى البريتوني. من هؤلاء؛ ١٠ مرضى (٨.٧٪) كان مستوى المغنيسيوم >٠.٧ ممول⁄ ل٬ وكان لدى ١٣ (١١.٣٪) ٧٬٠ممول⁄ ل٬ ولدى ٢٤ (٢٠.٩٪) ٠.٨ ممول⁄ ل٬ وعند ٢٦ (٢٢.٦٪) كان ٠.٩ ممول⁄ ل٬ وعند ١٦ (٩٬١٣٪) ٠٬١ ممول ⁄ ل٬ و ٢٦ (٢٣.٩٪) ظهرت المستويات ≥١٬١ممول⁄ ل. تقريبا كان لدى ٩٣٪ من العينة ارتفاع مستويات هرمون الغدة الجار درقية٬ و٤٣ (٣٧.٤٪) انخفاض مستوى الكالسيوم بالدم٬ و ٢٤ (٢٠.٩٪) انخفاض مستوى الكوليسترول و ٦٠ (٢٬٥٢٪) انخفاض الدهون الثلاثية بالدم. أظهر مرضى غسيل الكلى البيرتوني انخفاضا ملحوظا لمستويات المغنسيوم وارتفاعا لمستويات هرمون الغدة الجار درقية بالمقارنة بمرضى غسيل الكلى الدموي. الاستنتاجات: يعتبر مرضى الكلى المزمن عموما معرضين لخطر الإصابة بزيادة مغنيسيوم الدم بسبب انخفاض تخلص الكلى. ولكن عددا كبيرا من مرضى غسيل الكلى في وحدتنا لديهم انخفاض في مستويات المغنسيوم بدلا من ذلك. بالإضافة إلى عوامل أخرى يتأثر إفراز هرمون الغدة الجار درقية بمستويات المغنسيوم في الدم. كما وجدنا علاقة مهمة بين مستويات المغنسيوم بالدم والكالسيوم وكذلك هرمون الغدة الجار درقية. بناء على ذلك٬ فإن تحسين تركيز المغنسيوم عند مرضى غسيل الكلى مهم لتقليل خطر اضطراب دهون الدم٬ وعدم انتظام ضربات القلب٬ وفرط إفراز هرمون الغدة الجار درقية أو أمراض انعدام الحركة العظمية

Intermittent Oral Versus Intravenous Alfacalcidol in Dialysis Patients

Patients with end-stage renal failure (ESRF) on maintenance dialysis, commonly develop secondary hyperparathyroidism and renal osteodystrophy (ROD). Alfacalcidol, taken orally or administered intravenously, is known to reverse these complications. In this study, 19 ESRF patients, who were on dialysis (13 on hemodialysis and six on peritoneal dialysis) for longer than six months and having serum parathormone levels at least four times normal and serum calcium less than 2.1 mmol/L, were randomly allocated to treatment with oral or intravenous (i.v.) alfacalcidol for a period of 12 months. There were six patients on hemodialysis (HD) and three on peritoneal dialysis (PD) in the oral treatment group while in the i.v. group there were seven patients on HD and three on PD. Clinical and serial biochemical assessments showed no statistically significant difference between the orally- and i.v.-treated patients in terms of suppressing secondary hyperparathyroidism and osteodystrophy. However, patients with features of mild ROD on bone histology, had more satisfactory changes in biochemistry when compared to others. Our results further support the use of intermittent oral alfacalcidol in ESRF patients because of its cost effectiveness, ease of administration and convenience, especially for peritoneal dialysis patients

Cytomegalovirus disease in a renal transplant recipient: the importance of pre-transplant screening of the donor and recipient

A 16-year-old female patient who was born with a single kidney developed chronic kidney disease during her early childhood due to reflux nephropathy and recurrent urinary tract infection. She progressed to end-stage renal disease (ESRD) and was commenced on renal replacement therapy in the form of peritoneal dialysis in May 2011. Subsequently, she underwent living unrelated donor kidney transplantation in China. She was hospitalized soon after returning to Saudi Arabia for management of high-grade fever, shortness of breath, and deterioration of renal function, which was found to be due to cytomegalovirus (CMV) disease, proved by kidney biopsy and presence of high level of anti-CMV immunoglobulins. Allograft biopsy showed mature viral particles sized between 120 and 149 nm in the nuclei of the glomerular endothelial cells. The patient was treated with valgancyclovir and specific CMV immunoglobulin, as well as by reducing and even stopping the dose of tacrolimus and mycophenolate. Despite all these measures, her condition continued to deteriorate and she finally died. Our study emphasizes that unrelated renal transplantation, especially if unplanned and improperly prepared, is a very risky procedure that might transfer dangerous diseases and increase the morbidity and mortality of the patients. We strongly stress the need for mandatory and proper screening for CMV carrier status among donors as well as recipients prior to transplantation. Also, a recommendation is made to reject CMV-positive donors

Hepatitis G virus (HGV) infection in Saudi dialysis patients and healthy controls

Background: Viral hepatitis is a global health problem with a high mortality rate. End stage renal disease (ESRD) patients have a high prevalence of Hepatitis B and C virus infection. Present study was done to identify the prevalence and course of a new isolate Hepatitis G virus (HGV) infection in Saudi dialysis patients. Methods: The pattern of viral hepatitis infection (HBV. HCV and HGV) was investigated in 109 Saudi patients with ESRD and 100 healthy Saudi blood donors. Donated blood was tested for markers of Hepatitis B, C and G viruses. Liver functions were measured and blood picture and liver biopsies were also performed at regular intervals. Results: Out of the 109 ESRD patients 68 (62.4%) were positive for at least one viral marker: 59 (54.1%) were positive for HCV, six (5.5%) were positive for HGV and three (2.8%) were positive for HBsAg. Four of the six HGV positive patients were also co-infected with HCV. Eight (8%) of the blood donors were positive for at least one viral marker. Elevated ALT levels (>4 times normal) were recorded in four out of the six HGV-positive patients including three co-infected with HCV. Conclusions: Our results are in agreement with similar studies from different countries and also raise the question about the causal relationship between HGV and liver disease among dialysis patients