Three-D CFD Analysis of Hydrostatic Bearings

The hydrostatic bearing promises life and speed characteristics currently unachievable with rolling element bearings alone. In order to achieve the speed and life requirements of the next generation of rocket engines, turbopump manufacturers are proposing hydrostatic bearings to be used in place of, or in series with, rolling element bearings. The design of a hydrostatic bearing is dependent on accurate pressure in the bearing. The stiffness and damping of the hydrostatic bearing is very sensitive to the bearing recess pressure ratio. In the conventional approach, usually ad hoc assumptions were made in determining the bearing pressure of this approach is inherently incorrect. In the present paper, a more elaborate approach to obtain bearing pressure is used. The bearing pressure and complete flow features of the bearing are directly computed by solving the complete 3-D Navier Stokes equation. The code used in the present calculation is a modified version of REACT3D code. Several calculations have been performed for the hydrostatic bearing designed and tested at Texas A&M. Good agreement has been obtained between computed and test results. Detailed flow features in the bearing will also be described and discussed

Development of code evaluation criteria for assessing predictive capability and performance

Computational Fluid Dynamics (CFD), because of its unique ability to predict complex three-dimensional flows, is being applied with increasing frequency in the aerospace industry. Currently, no consistent code validation procedure is applied within the industry. Such a procedure is needed to increase confidence in CFD and reduce risk in the use of these codes as a design and analysis tool. This final contract report defines classifications for three levels of code validation, directly relating the use of CFD codes to the engineering design cycle. Evaluation criteria by which codes are measured and classified are recommended and discussed. Criteria for selecting experimental data against which CFD results can be compared are outlined. A four phase CFD code validation procedure is described in detail. Finally, the code validation procedure is demonstrated through application of the REACT CFD code to a series of cases culminating in a code to data comparison on the Space Shuttle Main Engine High Pressure Fuel Turbopump Impeller

Emphysematous Cystitis, A Rare Complication of Urinary Tract Infection in a Male Diabetic Patient: A Case Report

Emphysematous cystitis is a rare complication of urinary tract infection, characterized by spontaneous gas formation in the urinary bladder due to bacterial fermentation. Approximately 50 to 80% of patients with this disease are diabetic, and there is a higher incidence in females. We report a case of emphysematous cystitis in a diabetic male who was admitted under the impressions of hypoglycemia, acute bronchitis, and chronic renal failure. Treatment of the emphysematous cystitis consisted of adequate urinary drainage, empirical antibiotic therapy, and strict blood sugar control. The patient recovered satisfactorily after 9 days of hospitalization

The association of pioglitazone and urinary tract disease in type 2 diabetic Taiwanese: bladder cancer and chronic kidney disease.

OBJECTIVE: Although studies have shown an association between pioglitazone and bladder cancer, the associated factors have not been identified. The aim of this study was to investigate the factors that may link pioglitazone to bladder cancer. MATERIALS AND METHODS: In total, 34,970 study subjects were identified from the National Health Insurance Research Database in 2003 with follow-up from 2005 to 2009. The demographic characteristics of patients who had used and had never used pioglitazone, including age, sex, diabetes duration, urinary tract disease, nephropathy, bladder cancer, and cumulative dose and duration of pioglitazone therapy, were analyzed using the χ2 test. Cox proportional hazard regression models were used to determine the independent effects of pioglitazone on bladder cancer and newly developed chronic kidney disease. RESULTS: Among 3,497 ever users and 31,473 never users of pioglitazone, the respective incident cases of bladder cancer were 12 (0.4%) and 72 (0.2%), and for newly developed chronic kidney disease 245 (8.1%) and 663 (2.3%), respectively. Ever use of pioglitazone [1.59(1.32-1.91)], cumulative dose of pioglitazone <10,500 mg [1.69 (1.37-2.01)] and >10,500 mg [1.34 (1.04-1.73)], and duration of therapy <12 months [1.68 (1.36-2.08)] and >12 months [1.39 (1.09-1.76)] were associated with the development of chronic kidney disease. CONCLUSIONS: There was no association of pioglitazone use with bladder cancer development, however, there was an association with an increased risk of newly developed chronic kidney disease

Severe Hypoglycemia as a Predictor of End-Stage Renal Disease in Type 2 Diabetes: A National Cohort Study

Aims: This study investigated whether there is a link between severe hypoglycemia and progression into end-stage renal disease (ESRD) in patients with type 2 diabetes. Methods: Tapping into Taiwan&#8217;s Health Insurance Research Database, we identified all type 2 diabetes patients between 1996 and 2013 and identified those diagnosed with a severe hypoglycemia episode during an emergency department visit and those who were not. Controls were then matched 1:1 for age, sex, index year, and medication. Results: We identified 468,421 type 2 diabetes patients diagnosed as having severe hypoglycemia in an emergency department visit. Compared with controls, these patients with SH had a higher risk of all-cause mortality (Hazard Ratio (HR), 1.76; 95% confidence interval, 1.61&#8315;1.94) and progressed into ESRD within a shorter period of time. Results were similar after controlling for competing risk. Conclusion: Severe hypoglycemia is significantly associated with worsening renal dysfunction in patients with type 2 diabetes and hastened progression into ESRD

Acute Brachial Artery Thrombosis: A Rare Complication of Diabetic Ketoacidosis

Diabetes mellitus is a worldwide disease that leads to several acute complications including diabetic ketoacidosis, hyperosmolar hyperglycemia, and hypoglycemia. In addition, diabetes causes many chronic complications that lead to debilitation and diminished quality of life. Diabetic ketoacidosis is one of the serious acute complications; however, it is usually preceded by infection, acute myocardial infarction, stroke, or other dire events. Rarely does it accompany acute arterial thrombosis. Here, we report on a female patient who suffered from diabetic ketoacidosis combined with acute brachial artery thrombosis. After emergency treatment, including insulin therapy and surgical thrombectomy, the brachial artery was rescued and her prognosis was good

Association of Serum Uric Acid Concentration with Diabetic Retinopathy and Albuminuria in Taiwanese Patients with Type 2 Diabetes Mellitus

Patients with type 2 diabetes mellitus (DM) may experience chronic microvascular complications such as diabetic retinopathy (DR) and diabetic nephropathy (DN) during their lifetime. In clinical studies, serum uric acid concentration has been found to be associated with DR and DN. The goal of this study was to evaluate the relationship between the increases in serum uric acid level and the severity of DR and albuminuria in Taiwanese patients with type 2 DM. We recorded serum uric acid concentration, the severity of DR, and the severity of albuminuria by calculating urinary albumin-to-creatinine ratio (UACR) in 385 patients with type 2 DM. In multivariate logistic regression analysis, a high uric acid concentration was a risk factor for albuminuria (odds ratio (OR), 1.227; 95% confidence interval (CI) = 1.015–1.482; p = 0.034) and DR (OR, 1.264; 95% CI = 1.084–1.473; p = 0.003). We also demonstrated that there was a higher concentration of serum uric acid in the patients with more severe albuminuria and DR. In conclusion, an increased serum uric acid level was significantly correlated with the severity of albuminuria and DR in Taiwanese patients with type 2 DM

Statin, Calcium Channel Blocker and Beta Blocker Therapy May Decrease the Incidence of Tuberculosis Infection in Elderly Taiwanese Patients with Type 2 Diabetes

Background: It is well known that diabetes mellitus impairs immunity and therefore is an independent risk factor for tuberculosis. However, the influence of associated metabolic factors, such as hypertension, dyslipidemia and gout has yet to be confirmed. This study aimed to investigate whether the strong association between tuberculosis and diabetes mellitus is independent from the influence of hypertension and dyslipidemia, and its treatment in elderly Taiwanese patients. Methods: A total of 27,958 patients aged more than 65 years were identified from the National Health Insurance Research Database (NIHRD) in 1997 and were followed from 1998 to 2009. The demographic characteristics between the patients with and without diabetes were analyzed using the χ2 test. A total of 13,981 patients with type 2 diabetes were included in this study. Cox proportional hazard regression models were used to determine the independent effects of diabetes on the risk of tuberculosis. Results: After adjusting for age, sex, other co-morbidities and medications, calcium channel blocker, beta blocker and statin users had a lower independent association, with risk ratios of 0.76 (95% CI, 0.58–0.98), 0.72 (95% CI, 0.58–0.91) and 0.76 (95% CI, 0.60–0.97), respectively. Conclusion: Calcium channel blocker, beta blocker and statin therapy may decrease the incidence of tuberculosis infection in elderly Taiwanese patients with type 2 diabetes

Successful management of type IV hypersensitivity reactions to human insulin analogue with injecting mixtures of biphasic insulin aspart and dexamethasone

Although hypersensitivity reaction to insulin was supposed to be less-frequent with current insulin analogue, case reports with different types of allergic reactions to insulin analogue were still reported. The most common form is type I hypersensitivity reaction with IgE-mediated. Besides, type III (IgG and IgM-mediated) and type IV (T-cell mediated delayed reaction) hypersensitivity reactions were also reported. Here we presented a long-standing type 2 diabetes with insulin requirements with hypersensitivity reactions to insulin actrapid, insulin aspart, insulin glargine, insulin detemir, and biphasic insulin aspart 30. Insulin desensitization was performed as initial management but failed as skin biopsy with immunohistochemical staining proved type IV hypersensitivity reaction. We continued with the next treatment approach using subcutaneous injection with the mixture of biphasic insulin aspart 30 and dexamethasone to alleviate allergy, and the result was successful with steroid-free biphasic insulin aspart 30 injection eight months later. Besides, the treatment effect had lasted after ten years even with switched type of insulin analogue from biphasic insulin aspart 30 to insulin glargine and insulin aspart. The case report demonstrated a good example of how clinicians deal with the rare but important questions of hypersensitivity reactions to insulin analogue. Keywords: Insulin, Hypersensitivity, Glucocorticoid