Multiphase modeling of melting / solidification with high density variations using XFEM

La modélisation de la cryolite, utilisée dans la fabrication de l’aluminium, implique plusieurs défis, notament la présence de discontinuités dans la solution et l’inclusion de la difference de densité entre les phases solide et liquide. Pour surmonter ces défis, plusieurs éléments novateurs ont été développés dans cette thèse. En premier lieu, le problème du changement de phase, communément appelé problème de Stefan, a été résolu en deux dimensions en utilisant la méthode des éléments finis étendue. Une formulation utilisant un multiplicateur de Lagrange stable spécialement développée et une interpolation enrichie a été utilisée pour imposer la température de fusion à l’interface. La vitesse de l’interface est déterminée par le saut dans le flux de chaleur à travers l’interface et a été calculée en utilisant la solution du multiplicateur de Lagrange. En second lieu, les effets convectifs ont été inclus par la résolution des équations de Stokes dans la phase liquide en utilisant la méthode des éléments finis étendue aussi. Troisièmement, le changement de densité entre les phases solide et liquide, généralement négligé dans la littérature, a été pris en compte par l’ajout d’une condition aux limites de vitesse non nulle à l’interface solide-liquide pour respecter la conservation de la masse dans le système. Des problèmes analytiques et numériques ont été résolus pour valider les divers composants du modèle et le système d’équations couplés. Les solutions aux problèmes numériques ont été comparées aux solutions obtenues avec l’algorithme de déplacement de maillage de Comsol. Ces comparaisons démontrent que le modèle par éléments finis étendue reproduit correctement le problème de changement phase avec densités variables.

Biochemical parameters response to weight loss in patients with non-alcoholic steatohepatitis.

Background: Non-alcoholic steatohepatitis (NASH) is a chronic liver disease that is capable of progressing to end-stage liver disease, but generally has a benign course. Non-alcoholic steatohepatitis (NASH) is a growing public health problem with no approved therapy. NASH projected to be the leading cause of liver transplantation in the United States by 2020. Obesity, non-insulin-dependent diabetes mellitus and hyperlipidaemia are the most common associations of the disease. Global prevalence of NASH is 10-24% amongst general population but increases to 25-75% in obese diabetic individuals. Objective: There is an urgent need for efficient therapeutic options as there is still no approved medication. The aim of this study was to detect changes in biochemical parameters including insulin resistance, cytokines, blood lipid profile and liver enzymes following weight loss in patients with non-alcoholic steatohepatitis. Materials and methods: One hundred obese patients with NASH, their age between 35-50 years, body mass index (BMI) from 30 to 35 Kg/m2 were included in the study in two subgroups; the first group (A) received moderate aerobic exercise training in addition to diet regimen , where the second group (B) received no treatment intervention. Results: The mean values of leptin, TNF-α, IL6, IL8, Alanine Aminotransferase (ALT), Aspartate Aminotransferase (AST), Homeostasis Model Assessment-Insulin Resistance- index (HOMA-IR), Total Cholesterol (TC), Low Density Lipoprotein Cholesterol (LDL-c) , Triglycerides (TG) and BMI were significantly decreased in group (A), where the mean value of Adiponectin and High Density Lipoprotein Cholesterol (HDL-c) were significantly increased, while there were no significant changes in group (B). Also, there was a significant difference between both groups at the end of the study. Conclusion: Weight loss modulates insulin resistance, adiponectin, leptin, inflammatory cytokine levels and markers of hepatic function in patients with nonalcoholic steatohepatitis.

Treadmill walking exercise modulates bone mineral status and inflammatory cytokines in obese asthmatic patients with long term intake of corticosteroids.

Background: Obesity and asthma are an important public health problem in Saudi Arabia. An increasing body of data supports the hypothesis that obesity is a risk factor for asthma. Asthma appears to be associated with low bone mineral density (BMD) due to long-term use of corticosteroids. Studies recently showed that weight bearing exercise training can increase mineral bone density, reduce weight and improve metabolic control. Objective: The present study aimed to measure the effects of treadmill walking exercises on bone mineral status and inflammatory cytokines in obese asthmatic patients treated with long term intake of corticosteroids. Methods: Eighty obese asthmatic patients of both sexes, their age ranged from 41 to 53 years. Subjects were divided into two equal groups: training group (group A) received aerobic exercise training on treadmill for six months in addition to the medical treatment where, the control group (group B) received only the medical treatment. Results: The results of this study indicated a significant increase in BMD of the lumbar spine & the radius, serum calcium and high density lipoprotein cholesterol (HDL-c) & significant reduction in parathyroid hormone, leptin, tumor necrosis factor– alpha(TNF-α), interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-6 (IL-6), low density lipoprotein cholesterol (LDL-c), triglycerides (TG) and body mass index (BMI) in group (A), while these changes were not significant in group (B).Also; there was a significant difference between both groups at the end of the study. Conclusion: Treadmill walking exercise training is an effective treatment policy to improve bone mineral status and modulates inflammatory cytokines and blood lipids profile in obese asthmatic patients with long term intake of corticosteroids.

Comportamiento metabólico, fisiológico y electrocardiográfico en trabajadores expuestos a altas temperaturas en una empresa líder en la explotación y coquización del carbón en Boyacá, Colombia, 2016

Objetivo: Establecer la relación entre la exposición ocupacional a altas temperaturas o sobrecarga térmica con el comportamiento fisiológico, metabólico y electrocardiográfico. Métodos: estudio de corte transversal, donde se incluyeron dos grupos (expuesto y no expuesto a altas temperaturas) en una empresa minera, en el departamento de Boyacá, Colombia, en el año 2016. El número de participantes fue de 160 trabajadores del género masculino, grupo expuesto (n=86) y grupo no expuesto (n=74). La exposición ocupacional a sobrecarga térmica se evaluó con el índice de temperatura de globo y bulbo húmedo (TGBH), el comportamiento fisiológico con el índice de costo cardiaco relativo (ICCR) con mediciones de frecuencia cardiaca (FC), el comportamiento metabólico con la determinación del colesterol total (CT), colesterol de alta densidad (C-HDL), colesterol de baja densidad (C-LDL), triglicéridos (TG) y glicemia basal (GL). Las alteraciones electrocardiográficas con la toma de Electrocardiograma de 12 derivaciones. También fueron evaluadas variables antropométricas, tensión arterial, hábitos y antecedentes de enfermedad cardiovascular en ambos grupos. Resultados: incrementos significativos del ICCR (p<0.001) y la carga física (p<0.001) fueron encontrados en los trabajadores expuestos a altas temperaturas. Los índices lipídicos y glicemia, así como los antecedentes personales cardiovasculares, IMC, consumo de cigarrillo y consumo de alcohol, no mostraron significancia. El antecedente familiar de ACV (p=0.043) y el EKG alterado (p=0.011) mostraron una asociación significativa con la exposición a altas temperaturas. El modelo de regresión lineal múltiple explicó la relación entre el incremento del ICCR y la exposición a altas temperaturas (β=4,213, IC 95%: 1.57,6.85) ajustado por variables fisiológicas y electrocardiográficas. Conclusiones: La exposición ocupacional a altas temperaturas, presenta asociación con las alteraciones cardiovasculares a nivel fisiológico y electrocardiográfico, aumentando el ICCR y la carga física de trabajo (GE trabajo).

Función endotelial y lipemia postprandial en adultos normolipídicos: Efecto del estado nutricional

El objetivo del presente estudio fue cuantificar la contribución del sobrepeso en la magnitud de la lipemia posprandial en sujetos normolipídicos. Se incluyeron 33 adultos normolipídicos en dos grupos (n=20, sobrepeso y (n=13 eutróficos, 66% hombres, edad media 31,2±7,6 años). Se midió la vasodilatación mediada por flujo (VMF), la velocidad de onda de pulso (VOP), el perfil lipídico, el cociente Log TG/c-HDL, la glucosa y presión arterial tras una ingesta estándar con alto contenido de grasa (79% Kcal/grasa). Se calculó, el Z-score de riesgo cardiovascular a partir de la suma de los residuos tipificados (Z) de las variables de riesgo cardiovascular. El estado de lipemia posprandial se midió en ayuno (0 min) y a los (60, 120, 180, y 240 min) posprandiales. El valor basal de la VMF y la VOP fue de 6,9±5,9% y 7.0±0.8 m/s, respectivamente. Se identificó que la lipemia posprandial reducía la WMF en 19,2% a los 60 min (5,9±1,5%) y a los 240 min (3,7±1,2%) (p<0,04), respectivamente. Este hallazgo se acompañó con un aumento en la VOP (p<0,05). Al dividir los sujetos en dos grupos según el IMC, los participantes en sobrepeso muestran cifras más elevadas en el Z-score de riesgo cardiovascular, la VOP, el Log TG/c-HDL y el Δ-VOP, (p<0,001). En conclusión los sujetos clasificados en sobrepeso muestran un perfil cardiometabolico asociado con un mayor riesgo cardiovascular.

Increased cardio-metabolic risk is associated with increased TV viewing time

Purpose: Television viewing time, independent of leisure-time physical activity, has cross-sectional relationships with the metabolic syndrome and its individual components. We examined whether baseline and five-year changes in self-reported television viewing time are associated with changes in continuous biomarkers of cardio-metabolic risk (waist circumference, triglycerides, high density lipoprotein cholesterol, systolic and diastolic blood pressure, fasting plasma glucose; and a clustered cardio-metabolic risk score) in Australian adults. Methods: AusDiab is a prospective, population-based cohort study with biological, behavioral, and demographic measures collected in 1999–2000 and 2004–2005. Non-institutionalized adults aged ≥ 25 years were measured at baseline (11,247; 55% of those completing an initial household interview); 6,400 took part in the five-year follow-up biomedical examination, and 3,846 met the inclusion criteria for this analysis. Multiple linear regression analysis was used and unstandardized B coefficients (95% CI) are provided. Results: Baseline television viewing time (10 hours/week unit) was not significantly associated with change in any of the biomarkers of cardio-metabolic risk. Increases in television viewing time over five years (10 hours/week unit) were associated with increases in: waist circumference (cm) (men: 0.43 (0.08, 0.78), P = 0.02; women: 0.68 (0.30, 1.05), P <0.001), diastolic blood pressure (mmHg) (women: 0.47 (0.02, 0.92), P = 0.04), and the clustered cardio-metabolic risk score (women: 0.03 (0.01, 0.05), P = 0.007). These associations were independent of baseline television viewing time and baseline and change in physical activity and other potential confounders. Conclusion: These findings indicate that an increase in television viewing time is associated with adverse cardio-metabolic biomarker changes. Further prospective studies using objective measures of several sedentary behaviors are required to confirm causality of the associations found.

Waist circumference cut-off values for the prediction of cardiovascular risk factors clustering in Chinese school-aged children : a cross-sectional study

Background: Waist circumference has been identified as a valuable predictor of cardiovascular risk in children. The development of waist circumference percentiles and cut-offs for various ethnic groups are necessary because of differences in body composition. The purpose of this study was to develop waist circumference percentiles for Chinese children and to explore optimal waist circumference cut-off values for predicting cardiovascular risk factors clustering in this population.----- ----- Methods: Height, weight, and waist circumference were measured in 5529 children (2830 boys and 2699 girls) aged 6-12 years randomly selected from southern and northern China. Blood pressure, fasting triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and glucose were obtained in a subsample (n = 1845). Smoothed percentile curves were produced using the LMS method. Receiver-operating characteristic analysis was used to derive the optimal age- and gender-specific waist circumference thresholds for predicting the clustering of cardiovascular risk factors.----- ----- Results: Gender-specific waist circumference percentiles were constructed. The waist circumference thresholds were at the 90th and 84th percentiles for Chinese boys and girls respectively, with sensitivity and specificity ranging from 67% to 83%. The odds ratio of a clustering of cardiovascular risk factors among boys and girls with a higher value than cut-off points was 10.349 (95% confidence interval 4.466 to 23.979) and 8.084 (95% confidence interval 3.147 to 20.767) compared with their counterparts.----- ----- Conclusions: Percentile curves for waist circumference of Chinese children are provided. The cut-off point for waist circumference to predict cardiovascular risk factors clustering is at the 90th and 84th percentiles for Chinese boys and girls, respectively.

Is adiponectin implicated in venous thromboembolism?

In summary, these results imply that the relationship of adiponectin with lipoproteins is more complex than previously predicted using other methods of lipoprotein fractionation. Higher correlation of adiponectin was shown with large lipoprotein particle size, independent of the apolipoprotein content. Given the small population studied, we could not assess the influence of mild risk factors for venous thrombosis, such as obesity, on the analysis of the results. Thus, we can only state that adiponectin levels appear not to be a strong risk factor for VTE. It is possible that adiponectin deficiency may contribute indirectly to the etiology of VTE by enhancing the inflammatory state. © 2006 International Society on Thrombosis and Haemostasis.

Seasonal variation in cardiovascular disease risk factors in a subarctic population : the Tromso Study 1979-2008

Background Seasonal changes in cardiovascular disease (CVD) risk factors may be due to exposure to seasonal environmental variables like temperature and acute infections or seasonal behavioural patterns in physical activity and diet. Investigating the seasonal pattern of risk factors should help determine the causes of the seasonal pattern in CVD. Few studies have investigated the seasonal variation in risk factors using repeated measurements from the same individual, which is important as individual and population seasonal patterns may differ. Methods The authors investigated the seasonal pattern in systolic and diastolic blood pressure, heart rate, body weight, total cholesterol, triglycerides, high-density lipoprotein cholesterol, C reactive protein and fibrinogen. Measurements came from 38 037 participants in the population-based cohort, the Tromsø Study, examined up to eight times from 1979 to 2008. Individual and population seasonal patterns were estimated using a cosinor in a mixed model. Results All risk factors had a highly statistically significant seasonal pattern with a peak time in winter, except for triglycerides (peak in autumn), C reactive protein and fibrinogen (peak in spring). The sizes of the seasonal variations were clinically modest. Conclusions Although the authors found highly statistically significant individual seasonal patterns for all risk factors, the sizes of the changes were modest, probably because this subarctic population is well adapted to a harsh climate. Better protection against seasonal risk factors like cold weather could help reduce the winter excess in CVD observed in milder climates.

Linkage mapping of CVD risk traits in the isolated Norfolk Island population

To understand the underlying genetic architecture of cardiovascular disease (CVD) risk traits, we undertook a genome-wide linkage scan to identify CVD quantitative trait loci (QTLs) in 377 individuals from the Norfolk Island population. The central aim of this research focused on the utilization of a genetically and geographically isolated population of individuals from Norfolk Island for the purposes of variance component linkage analysis to identify QTLs involved in CVD risk traits. Substantial evidence supports the involvement of traits such as systolic and diastolic blood pressures, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, body mass index and triglycerides as important risk factors for CVD pathogenesis. In addition to the environmental inXuences of poor diet, reduced physical activity, increasing age, cigarette smoking and alcohol consumption, many studies have illustrated a strong involvement of genetic components in the CVD phenotype through family and twin studies. We undertook a genome scan using 400 markers spaced approximately 10 cM in 600 individuals from Norfolk Island. Genotype data was analyzed using the variance components methods of SOLAR. Our results gave a peak LOD score of 2.01 localizing to chromosome 1p36 for systolic blood pressure and replicated previously implicated loci for other CVD relevant QTLs.

Antioestrogens and breast cancer

Antioestrogens are among the most widely used agents in the treatment of breast cancer. There has been a recent surge of interest in these compounds because of their potential breast cancer chemopreventive properties. The newer generation of antioestrogens, with increased selectivity and better toxicity profiles, have the potential to increase the effectiveness of hormonal treatment of breast cancer. The selective oestrogen receptor modulators (SERMs) hold the promise of revolutionising the care of healthy postmenopausal women with their beneficial effects on bone and lipids in addition to the chemoprevention of breast cancer.

Diabetes, hyperinsulinemia, and hyperlipidemia in small aboriginal community in northern Australia

A small rural Aboriginal community in northern Australia was surveyed for diabetes, impaired glucose tolerance (IGT), hyperinsulinemia, and lipid levels. Of the 122 adults >17 yr of age who participated (95% response rate), 11.5% had diabetes, 7.4% had IGT, and the remaining 81.1% had normal glucose tolerance. Both diabetes and IGT were strongly age related. This high frequency of diabetes occurred, despite the population being relatively lean. Although the body mass index (BMI) increased with age in both men and women, only 25% of the population overall had BMI >25 kg/m2. There were wide ranges of insulin responses to glucose, with the upper fertile of 2-h insulin levels being more than seven times higher than the lower fertile (144 ± 13 vs. 19 ± 1 mLI/L). Hyperinsulinemia was associated with IGT, elevated triglycerides, and lower high-density lipoprotein cholesterol levels. Lipid abnormalities were much more frequent among men than women. Cholesterol levels were an average of 0.55 mM higher and triglycerides an average of 1.05 mM higher in men than in women, and both increased with age. In conclusion, this small isolated Aboriginal population from northern Australia had an unexpectedly high frequency of diabetes (in view of their relative leanness) in association with a high frequency of metabolic abnormalities indicative of insulin resistance (hyperinsulinemia, IGT, hypertriglyceridemia).

Canagliflozin : something new for type 2 diabetes, but is it safe and efficacious?

Evaluation of Inagaki N, Kondo K, Yoshinari T, et al. Efficacy and safety of canagliflozin in Japanese patients with type 2 diabetes: a randomized, double-blind, placebo-controlled, 12-week study. Diabetes Obes Metab 2013. [Epub ahead of print] and Cefalu WT, Leiter LA, Yoon KH, et al. Efficacy and safety of canagliflozin versus glimepiride in patients with type 2 diabetes inadequately controlled with metformin (CANTATA-SU): 52 week results from a randomized, double-blind, phase 3 non-inferiority trial. Lancet 2013;382:941-50 INTRODUCTION Inhibition of the sodium-glucose cotransporter 2 (SGLT2), to promote the excretion of glucose, is a new paradigm in the treatment of type 2 diabetes. AREAS COVERED Canagliflozin is an SGLT2 inhibitor, which has been the subject of two recent clinical trials, which are evaluated. EXPERT OPINION Studies with canagliflozin, in subjects with type 2 diabetes, have shown that its use is associated with reductions in HbA1c and body weight and small reductions in blood pressure and triglycerides, while increasing high-density lipoprotein cholesterol and low-density lipoprotein cholesterol. As monotherapy in Japanese subjects, or in comparison with glimepiride in CANTATA-SU (CANagliflozin Treatment and Trial Analysis versus SUlphonylurea), canagliflozin causes a low incidence of hypoglycemia, and this is an advantage over glimepiride. However, one of the disadvantages with canagliflozin, which was also highlighted in CANTATA-SU, is that canagliflozin can cause urogenital infections, which are not observed with other antidiabetic drugs. The Federal Drug Administration has recently approved canagliflozin for use in type 2 diabetes, while directing that a clinical outcome safety trial be undertaken. We are concerned that canagliflozin has been approved for use in type 2 diabetes prior to a clinical outcome study of efficacy being undertaken and without the outcome of further safety testing.

Moderate physical activity level as a protective factor against metabolic syndrome in middle-aged and older women

Aims and objectives To investigate whether physical activity is a protective factor against metabolic syndrome in middle-aged and older women. Background Socio-demographic and lifestyle behaviour factors contribute to metabolic syndrome. To minimise the risk of metabolic syndrome, several global guidelines recommend increasing physical activity level. However, only limited research has investigated the relationship between physical activity levels and metabolic syndrome in middle-aged and older women after adjusting for socio-demographic and lifestyle behaviour factors. Design Cross-sectional design. Methods A convenience sample of 326 middle-aged and older women was recruited. Metabolic syndrome was confirmed according to the National Cholesterol Education Program, Adult Treatment Panel III guidelines, and physical activity levels were measured by the International Physical Activity Questionnaire. Results The sample had a mean age of 60•9 years, and the prevalence of metabolic syndrome was 43•3%. Postmenopausal women and women with low socioeconomic status (low-education background, without personal income and currently unemployed) had a significantly higher risk of developing metabolic syndrome. After adjusting for significant socio-demographic and lifestyle behaviour factors, the women with moderate or high physical activity levels had a significantly lower (OR = 0•10; OR = 0•11, p < 0•001) risk of metabolic syndrome and a lower risk for each specific component of metabolic syndrome, including elevated fasting plasma glucose (OR = 0•29; OR = 0•26, p = 0•009), elevated blood pressure (OR = 0•18; OR = 0•32, p = 0•029), elevated triglycerides (OR = 0•41; OR = 0•15, p = 0•001), reduced high-density lipoprotein (OR = 0•28; OR = 0•27, p = 0•004) and central obesity (OR = 0•31; OR = 0•22, p = 0•027). Conclusions After adjusting for socio-demographic and lifestyle behaviour factors, physical activity level was a significant protective factor against metabolic syndrome in middle-aged and older women. Higher physical activity levels (moderate or high physical activity level) reduced the risk of metabolic syndrome in middle-aged and older women. Relevance to clinical practice Appropriate strategies should be developed to encourage middle-aged and older women across different socio-demographic backgrounds to engage in moderate or high levels of physical activity to reduce the risk of metabolic syndrome.