Forced Convection Cooling of Electric Motors Using Enhanced Surfaces

Electric motors are extensively engaged in industrial and commercial applications such as electrical cars, energy-conversion systems, elevators, and actuators for aircrafts. Due to the significant internal heat generation, it is usually a challenge to design and manufacture high power density, high reliability, and low cost electric motors with superior performance. One of the efficient ways to dissipate the heat generated in the electrical motor is by using extended surfaces (i.e. heat sinks). These surfaces are extruded from the motor casing and air is forced though them by a cooling fan. This cooling approach is simple to be implemented and has zero carbon emission to the environment. Adding ribs on the motor extended surface enhances the heat dissipation rate. This project is intended to study numerically the effect of varying ribs spacing and ribs heights on heat removal efficiency, accounting for the relative change in heat transfer coefficient and pressure drop compared to those for a smooth flow channel. The study is conducted to simulate the airflow field, and heat transfer for a plate heat sink using ANSYS V.16. The domain considered in the present work is a simple design of an electric motor annulus. The electric motor annulus consists of an array of ribbed fins. Heat source is represented as a uniform heat flux of 12250 W/m2 at the bottom surface of the heat sink base. Through the simulations, the rib heights (e=0.05, 0.1, 0.2, in mm) and spacing (p=1, 2,3,4,5, in mm) between the ribs, the channel width (Wch= 2 and 6 in mm), and the rib configuration (continues and inline ribs) are varied to study their effect on the performance of the heat sink for a Reynolds number range from 3133 to 12532. To assess which rib configuration is best, a figure of merit (named as thermal-hydraulic performance) is used which is defined as the ratio of heat transfer enhancement to the increase in pumping power due to the presence of the ribs. The highest thermal-hydraulic performance value out of all the transverse cases at Wch=2 mm in this study was 1.07 at e=0.05 mm, p=4 mm, and Re=3133 which means only a 7% enhancement is obtained. These set of cases are suitable for increasing the rate of heat transfer while ignoring the pressure drop penalty. Changing the channel width to 6 mm increases the thermal-hydraulic performance by about 23%. Therefore, this channel width is used for the inline ribs configurations with seven different opening ratios (10% to 70%). The inline ribs are investigated at two different Reynolds number (3133 and 12532). At an opening ratio of 50% the highest thermal-hydraulic performance of 1.18 and 1.22 were found at Re=3133 and p=5 mm, and at Re=3133 and p=1 mm, respectively. These simulation results show that with proper channel and ribs configuration, one can achieve about 22% increase in the thermal-hydraulic performance ratio over that of the smooth channel

Stereotactic body radiation therapy for abdominal oligometastases: a biological and clinical review

Advances in imaging and biological targeting have led to the development of stereotactic body radiation therapy (SBRT) as an alternative treatment of extracranial oligometastases. New radiobiological concepts, such as ceramide-induced endothelial apoptosis after hypofractionated high-dose SBRT, and the identification of patients with oligometastatic disease by microRNA expression may yet lead to further developments. Key factors in SBRT are delivery of a high dose per fraction, proper patient positioning, target localisation, and management of breathing–related motion. Our review addresses the radiation doses and schedules used to treat liver, abdominal lymph node (LN) and adrenal gland oligometastases and treatment outcomes. Reported local control (LC) rates for liver and abdominal LN oligometastases are high (median 2-year actuarial LC: 61 -100% for liver oligometastases; 4-year actuarial LC: 68% in a study of abdominal LN oligometastases). Early toxicity is low-to-moderate; late adverse effects are rare. SBRT of adrenal gland oligometastases shows promising results in the case of isolated lesions. In conclusion, properly conducted SBRT procedures are a safe and effective treatment option for abdominal oligometastases

CONCOMITANT USE OF NON-STEROIDAL ANTI-INFLAMMATORY DRUGS (NSAIDS) WITH WARFARIN

Introduction: Oral anticoagulation with warfarin is the accepted technique for treatment and prophylaxis of thromboembolic diseases. Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most broadly administered medications to control musculoskeletal pain or inflammation. besides to their antiplatelet work, NSAIDs can influence the pharmacologic activity of warfarin through their immediate interaction. High protein binding and the cytochrome P450 (CYP)- dependent clearance systems of NSAIDs can influence the serum levels of warfarin. Aim of work: In this review, we will discuss whether using warfarin with NSAID has any effect on the pharmacokinetics and pharmacodynamics of both drugs. Methodology: We conducted this review using a comprehensive search of MEDLINE, PubMed, and EMBASE, January 1985, through February 2017. The following search terms were used: Non-steroidal anti-inflammatory drug mechanism, warfarin mechanism, adverse effects of NSAID, adverse effect of warfarin, NSAID-warfarin interaction Conclusions: Co-administration of NSAIDs and Warfarin is a topic of debate. However, there are reasons for concern. Some NSAIDs alter hemostasis and, when combined with warfarin, may lead to an increase in bleeding time. There is also a risk of increased hepatic and renal toxicity which complicates things further. Balancing the pros and cons of this drug combination should be carefully done on a case to case basis to avoid any negative consequences. Key words: NSAID, warfarin, Aspirin, drug-drug interaction, bleedin

Vitamin D serum level predicts stroke clinical severity, functional independence, and disability—A retrospective cohort study

BackgroundStroke is a leading cause of mortality and disability and one of the most common neurological conditions globally. Many studies focused on vitamin D as a stroke risk factor, but only a few focused on its serum level as a predictor of stroke initial clinical severity and recovery with inconsistent results. The purpose of this study was to assess the relationship between serum vitamin D levels and stroke clinical severity at admission and functional independence and disability at discharge in Saudi Arabia.MethodologyA retrospective cohort study of adult ischemic stroke patients who had their vitamin D tested and admitted within 7 days of exhibiting stroke symptoms at King Abdulaziz Medical City (KAMC) Jeddah, Saudi Arabia. Based on vitamin D level, the patients were categorized into normal [25(OH)D serum level ≥ 75 nmol/L], insufficient [25(OH)D serum level is 50–75 nmol/L], and deficient [25(OH)D serum level ≤ 50 nmol/L]. The primary outcome was to assess the vitamin D serum level of ischemic stroke patients’ clinical severity at admission and functional independence at discharge. The National Institute of Health Stroke Scale (NIHSS) was used to assess the clinical severity, whereas the modified Rankin scale (mRS) was used to assess functional independence and disability.ResultsThe study included 294 stroke patients, out of 774, who were selected based on the inclusion and exclusion criteria. The mean age of the participants was 68.2 ± 13.4 years, and 49.3% were male. The patients’ distribution among the three groups based on their vitamin D levels is: normal (n = 35, 11.9%), insufficient (n = 66, 22.5%), and deficient (n = 196, 65.6%). After adjusting for potential covariates, regression analysis found a significant inverse relationship of NIHSS based on 25(OH)D serum level (beta coefficient: −0.04, SE: 0.01, p = 0.003). Patients with deficient serum vitamin D level also had significantly higher odds of worse functional independence in mRS score [OR: 2.41, 95%CI: (1.13–5.16), p = 0.023] when compared to participants with normal vitamin D level.ConclusionLow vitamin D levels were associated with higher severity of stroke at admission and poor functional independence and disability at discharge in patients with acute ischemic stroke. Further randomized clinical and interventional studies are required to confirm our findings

The Saudi Critical Care Society practice guidelines on the management of COVID-19 in the ICU: Therapy section

BACKGROUND: The rapid increase in coronavirus disease 2019 (COVID-19) cases during the subsequent waves in Saudi Arabia and other countries prompted the Saudi Critical Care Society (SCCS) to put together a panel of experts to issue evidence-based recommendations for the management of COVID-19 in the intensive care unit (ICU). METHODS: The SCCS COVID-19 panel included 51 experts with expertise in critical care, respirology, infectious disease, epidemiology, emergency medicine, clinical pharmacy, nursing, respiratory therapy, methodology, and health policy. All members completed an electronic conflict of interest disclosure form. The panel addressed 9 questions that are related to the therapy of COVID-19 in the ICU. We identified relevant systematic reviews and clinical trials, then used the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach as well as the evidence-to-decision framework (EtD) to assess the quality of evidence and generate recommendations. RESULTS: The SCCS COVID-19 panel issued 12 recommendations on pharmacotherapeutic interventions (immunomodulators, antiviral agents, and anticoagulants) for severe and critical COVID-19, of which 3 were strong recommendations and 9 were weak recommendations. CONCLUSION: The SCCS COVID-19 panel used the GRADE approach to formulate recommendations on therapy for COVID-19 in the ICU. The EtD framework allows adaptation of these recommendations in different contexts. The SCCS guideline committee will update recommendations as new evidence becomes available

Isolation and Characterisation of Bacteriophages That Infect Capsulated Streptococcus pneumonia

S. pneumoniae (pneumococcus) is a major cause of pneumonia, sepsis, and meningitis, responsible for over 1.2 million deaths per year. Rates of antibiotic resistance are rising, with over one third of isolates in the US and parts of Europe showing a reduced susceptibility to penicillin. Although pneumococcal conjugate vaccines have resulted in a decline in invasive disease caused by the pneumococcal serotypes included in the vaccine, non-vaccine serotypes have been shown to cause replacement disease. To address these important clinical challenges and provide cross serotype protection against pneumococcal infection, alternative therapies are urgently needed such as the exploitation of bacteriophages, which can specifically target and kill pneumococci. Bacteriophages are being developed to treat a range of bacterial pathogens due to their ability to kill pathogens which are resistant to conventional antibiotics, and due to their specificity and ability to access and replicate in difficult micro-environments within the human body. Although the previously isolated pneumococcal lytic phages; Dp-1 and Cp-1 showed promise as a treatment for pneumococcal infection, they could only infect non-capsulated strains, which are attenuated and non-invasive in the human clinical setting. This project describes the isolation and characterisation of a new lytic phage SP-QS1, which can infect and significantly reduce the load of capsulated pneumococcal strains that cause human invasive disease. SP-QS1 is a distinctive new siphovirus with prolated-head, non-contractile tail and tail fibres. The interaction between SP-QS1 and S. pneumoniae in both in vitro and in in vivo assays demonstrated that it is able to significantly reduce the amount of S. pneumoniae in two mouse models of invasive pneumonia; the intranasal and the intravenous model of infections. The genomic sequencing of SP-QS1 revealed that genes with recognisable homologies are often ordered according to the following; genes involved in phage packaging, structural proteins, replication and genes associated with cell lysis. Interestingly, SP-QS1 genome does not encode CRISPR sequences, proteins with trans-membrane domains or regulatory elements. In addition, because the phage genome does not encode integrase genes, it appears to be a genuine lytic phage. Genetic characterisation of SP-QS1 genome illustrated that this phage encodes for glycosyltransferase, and it is suggested to be responsible for capsule degradation. SP-QS1 shows promise to control and treat the infections caused by S. pneumoniae

A rare sporadic case of C3 gene mutation in 5-month-old baby girl with atypical hemolytic uremic syndrome, with good prognosis

Atypical hemolytic uremic syndrome (aHUS) is a rare form of thrombotic microangiopathy representing A, p.(Asp1115Asn). The early recognition and administration of eculizumab are a lifesaving measure. C3 gene mutations are an autosomal dominant inherited pattern, with 50% risk of inheriting this mutation. Therefore, genetic counseling and family member testing are recommended

Multidrug-Resistant Acinetobacter baumannii: An Emerging Health Threat in Aseer Region, Kingdom of Saudi Arabia

Objective. The study aims to determine the prevalence of multidrug-resistant A. baumannii in Aseer Region, Kingdom of Saudi Arabia. Methods. This study evaluated the antibiotic susceptibility of ninety-four (n = 94) clinical isolates of A. baumannii. The isolates were collected from the south region of Saudi Arabia, and notably Aseer Region, during the period from 15 October 2014 to 15 January 2015. The isolates were tentatively identified as A. baumannii by routine bench tests and were confirmed by using VITEK® 2 Compact. The latest instrument was used to identify antibiotic susceptibility of these isolates. Results. Antibiotic susceptibility in this study showed that 69% of these isolates were multidrug-resistant strains. Moreover, they were highly resistant to carbapenem drugs. Several strains of these isolates were found to be extremely resistant to test antibiotics and were only sensitive to one or two of them. Conclusion. High rate of multidrug-resistant A. baumannii bacteraemia has emerged in the south region of Saudi Arabia as an important health problem. Therefore, it is considered as a new threat in hospitals, which requires a tremendous effort to stop its escalation and spread

Delayed Guillain-Barré Syndrome after Bariatric Surgery: A Report of Three Cases

Surgeries carry a risk of complications. Polyneuropathies, including Guillain-Barré syndrome (GBS), are potential complications of bariatric surgery. The incidence of these conditions is expected to increase as these surgeries become increasingly popular. We present a case report of three patients who developed a polyneuropathy after bariatric surgery. GBS was diagnosed in each patient, with nutritional deficiencies being suspected as a contributing factor. All patients began a 5-day intravenous immunoglobulin course in addition to receiving rehabilitative support, multivitamins, intravenous thiamine, vitamin D (therapeutic dose), and selenium. The patients’ symptoms improved but did not completely resolve. GBS can be a complication of bariatric surgery. Although a clear cause-effect relationship cannot be established for the present cases, the cumulative literature on the subject suggests that it is important to include it as a potential risk when counseling patients for such surgeries