A numerical study of the longitudinal thermoconvective rolls in a mixed convection flow in a horizontal channel with a free surface

This paper presents a numerical study of three-dimensional laminar mixed convection within a liquid flowing on a horizontal channel heated uniformly from below. The upper surface is free and assumed to be flat. The coupled Navier-Stokes and energy equations are solved numerically by the finite volume method taking into account the thermocapillary effects (Marangoni effect). When the strength of the buoyancy, thermocapillary effects and forced convective currents are comparable $(Ri\backsimeq O(1)$ and $Bd=Ra/Ma \backsimeq O(1))$, the results show that the development of instabilities in the form of steady longitudinal convective rolls is similar to those encountered in the Poiseuille-Rayleigh-B\'enard flow. The number and spatial distribution of these rolls along the channel depend on the flow conditions. The objective of this work is to study the influence of parameters, such as the Reynolds, Rayleigh and Biot numbers, on the flow patterns and heat transfer characteristics. The effects of variations in the surface tension with temperature gradients (Marangoni effect) are also considered

Successful rescue therapy with tenofovir in a patient with hepatic decompensation and adefovir resistant HBV mutant

BACKGROUND: Prolonged adefovir therapy exposes to the emergence of adefovir resistant hepatitis B virus mutants. Initial reports of the rtN236T mutation showed preserved sensitivity to lamivudine; however, complex mutations are emerging with reduced susceptibility to lamivudine. CASE PRESENTATION: After 2 years of therapy, a cirrhotic patient developed the rtN236T and rtA181T adefovir resistant mutations. He had been previously treated with lamivudine, developed lamivudine resistance and, despite good compliance, had an incomplete response to adefovir. Adefovir resistance resulted in viral breakthrough with hepatitis flare-up and liver decompensation. Tenofovir had an excellent antiviral effect allowing sustained control of viral replication and reversal of hepatic failure. CONCLUSION: In patients with cirrhosis, adefovir resistance can lead to severe hepatitis. Tenofovir appears to be an effective treatment of adefovir resistant mutants. Incomplete control of viral replication with adefovir requires monitoring for viral resistance and should prompt a change in antiviral treatment

Mesure continue du glucose (ce système a-t-il répondu aux attentes du patient dans la prise en charge de son diabète ?)

La mesure en continu du glucose (MCG) avec affichage en temps réel a déjà prouvé son efficacité sur l équilibre métabolique en diminuant l HbA1c et la variabilité glycémique sans augmenter le nombre d hypoglycémies. L objectif principal de cette étude monocentrique, rétrospective et prospective, est d évaluer les attentes initiales des patients équipés d un capteur et d analyser le service rendu à partir d un questionnaire. Les objectifs secondaires sont d étudier après trois mois d utilisation, les changements de comportements du patient et les conséquences métaboliques (HbA1c), ainsi que le nombre d hypoglycémies sévères avec l utilisation de l arrêt automatique de la pompe. Entre avril 2009 et juillet 2012, au CHU de Grenoble, 35 patients adultes diabétiques de type 1, sous pompe à insuline externe pour 33 d entre eux, avec une HbA1c initiale moyenne de 8,1 +- 1,4%, ont été équipés de capteurs. On observe une satisfaction prédominante sur la prévention des hypoglycémies (100% des patients) puis sur le contrôle des hyperglycémies (88%). 51% des patients ont abandonné le système, lié en grande partie à l anxiété générée par les alertes et aux difficultés techniques. Après 3 mois d utilisation, le nombre moyen de bolus par jour a augmenté de 56% (p = 0,06) le temps d arrêt temporaire moyen de la pompe a également augmenté de 34% (p = 0,09). La baisse moyenne de l HbA1c observée à 3 mois est de 0,31% (n=23) et de 1,15% pour les patients ayant une HbA1c > 9%. Sur les 17 patients équipés de l arrêt automatique de pompe, aucun n a eu d hypoglycémie sévère. Ce système est donc une aide pour le patient s il est associé à un programme d éducation thérapeutique spécifique.Continuous glucose monitoring proved its effectiveness in reducing HbA1c and glycemic variability without increasing hypoglycemia number. The main objective of this single-center retrospective and prospective study is to assess the initial expectations of patients fitted with a sensor and analyze this service from a questionnaire. Secondary objectives consist in evaluating after three months of use patient's behavioral changes, metabolic consequences (HbA1c) and severe hypoglycemia number with the use of automated insulin suspension. Between April 2009 and July 2012, in Grenoble University Hospital, 35 adult patients with type 1 diabetes were equipped of sensors. 33 of them have been treated with continuous subcutaneous insulin infusion, with a mean baseline HbA1c of 8.1 +- 1.4%. The predominant satisfaction is hypoglycemia prevention (100% of patients) and secondarily hyperglycemia control (88%). 51% of patients have dropped out, mostly related to the anxiety generated by alerts and technical difficulties. After 3 months of use the average number of bolus per day increased by 56% (p = 0.06). The temporary insulin suspension was also increased by 34% (p = 0.09). The mean decrease in HbA1c observed at 3 months was 0.31% (n = 23) and 1.15% for patients with HbA1c > 9%. None of the 17 patients fitted with automated insulin suspension had severe hypoglycemia. Therefore, this system can help the patient when it is associated with a specific therapeutic education program.GRENOBLE1-BU Médecine pharm. (385162101) / SudocSudocFranceF

Long-term treatment of postmenopausal osteoporotic women with strontium ranelate : results at 10 years

Peer reviewe

Combining Glucose Monitoring and Insulin Infusion in an Integrated Device: A Narrative Review of Challenges and Proposed Solutions.

The introduction of automated insulin delivery (AID) systems has enabled increasing numbers of individuals with type 1 diabetes (T1D) to improve their glycemic control largely. However, use of AID systems is limited due to their complexity and costs associated. The user must wear both a continuously monitoring glucose system and an insulin infusion pump. The glucose sensor and the insulin catheter must be inserted at two different body sites using different insertion devices. In addition, the user must pair and manage the different systems. These communicate with the AID software implemented on the pump or on a third device such as a dedicated display device or smart phone application. These components might be developed and commercialized by different manufacturers, which in turn can cause difficulties for patients seeking technical support. A possible solution to these challenges would be to integrate the glucose sensor and insulin catheter into a single device. This would allow the glucose sensor and insulin catheter to be inserted simultaneously, eliminating the need for pairing, and simplifying system management. In recent years, different technologies have been developed and evaluated in clinical investigations that combine the glucose sensor and the insulin catheter in one platform. The consistent finding of all these studies is that integration has no adverse effect on insulin infusion and glucose measurements provided that certain conditions are met. In this review, we discuss the perceived challenges of such an approach and discuss possible solutions that have been proposed

Overview of the diagnostic value of biochemical markers of liver fibrosis (FibroTest, HCV FibroSure) and necrosis (ActiTest) in patients with chronic hepatitis C

BACKGROUND: Recent studies strongly suggest that due to the limitations and risks of biopsy, as well as the improvement of the diagnostic accuracy of biochemical markers, liver biopsy should no longer be considered mandatory in patients with chronic hepatitis C. In 2001, FibroTest ActiTest (FT-AT), a panel of biochemical markers, was found to have high diagnostic value for fibrosis (FT range 0.00–1.00) and necroinflammatory histological activity (AT range 0.00–1.00). The aim was to summarize the diagnostic value of these tests from the scientific literature; to respond to frequently asked questions by performing original new analyses (including the range of diagnostic values, a comparison with other markers, the impact of genotype and viral load, and the diagnostic value in intermediate levels of injury); and to develop a system of conversion between the biochemical and biopsy estimates of liver injury. RESULTS: A total of 16 publications were identified. An integrated database was constructed using 1,570 individual data, to which applied analytical recommendations. The control group consisted of 300 prospectively studied blood donors. For the diagnosis of significant fibrosis by the METAVIR scoring system, the areas under the receiver operating characteristics curves (AUROC) ranged from 0.73 to 0.87. For the diagnosis of significant histological activity, the AUROCs ranged from 0.75 to 0.86. At a cut off of 0.31, the FT negative predictive value for excluding significant fibrosis (prevalence 0.31) was 91%. At a cut off of 0.36, the ActiTest negative predictive value for excluding significant necrosis (prevalence 0.41) was 85%. In three studies there was a direct comparison in the same patients of FT versus other biochemical markers, including hyaluronic acid, the Forns index, and the APRI index. All the comparisons favored FT (P < 0.05). There were no differences between the AUROCs of FT-AT according to genotype or viral load. The AUROCs of FT-AT for consecutive stages of fibrosis and grades of necrosis were the same for both moderate and extreme stages and grades. A conversion table was constructed between the continuous FT-AT values (0.00 to 1.00) and the expected semi-quantitative fibrosis stages (F0 to F4) and necrosis grades (A0 to A3). CONCLUSIONS: Based on these results, the use of the biochemical markers of liver fibrosis (FibroTest) and necrosis (ActiTest) can be recommended as an alternative to liver biopsy for the assessment of liver injury in patients with chronic hepatitis C. In clinical practice, liver biopsy should be recommended only as a second line test, i.e., in case of high risk of error of biochemical tests

Stabilité linéaire de l'écoulement de convection mixte et thermocapillaire d'un film liquide sur un plan horizontal chauffé uniformément par le bas

Nous présentons une analyse de stabilité linéaire d'un écoulement laminaire de convection mixte d'un film liquide sur un plan horizontal chauffé uniformément par le bas. La variation de la tension de surface avec la température (effet Marangoni) est prise en compte. La méthode spectrale de collocation basée sur les polynômes de Chebyshev a été employée pour résoudre le système aux valeurs propres du problème. Dans cette configuration plusieurs types de structures thermoconvectives sont susceptibles d’apparaître [1,2]. Nous nous sommes intéressés à deux modes d'instabilités thermoconvectives qui donnent naissance à des rouleaux longitudinaux ou à des rouleaux transversaux. Les rouleaux transversaux apparaissent pour des écoulements à faible nombre de Reynolds. Cette analyse de stabilité a permis d'obtenir les diagrammes de stabilité caractérisant les seuils de perte de stabilité de l'écoulement vis à vis de ces deux modes d'instabilité et l'étude de leur variation avec les paramètres de contrôle de l'écoulement. La forme des structures spatiales de l'écoulement est présentée. Par comparaison avec l'écoulement de Poiseuille-Rayleigh-Bénard, très étudié dans la littérature, la présence de la surface supérieure libre rend l'écoulement toujours plus instable vis-à-vis des rouleaux longitudinaux et plus ou moins stable vis-à-vis des rouleaux transversaux selon les nombres de Biot, de Reynolds et de Prandtl considérés. Les résultats montrent aussi que les forces thermogravitaires et les forces thermocapillaires se renforcent mutuellement pour rendre le système plus instable. [1] Bammou L., Instabilité thermoconvective de l'écoulement de Poiseuille-Rayleigh-Bénard-Marangoni dans un canal ouvert à surface libre. Thèse de doctorat, Université de Pau et des Pays de l'Adours, 13 décembre 2012. [2] Bammou L., El Omari K., Le Guer Y., Blancher S., Benhamou B., Mediouni T., Numerical study of longitudinal thermoconvectives rolls in mixed convection flow in a horizontal channel with fre­e surface, accepted in Int. J. of Heat and Fluid Flow, 2013

Changing pattern of age-specific breast cancer incidence in the Swiss canton of Geneva

Hormone replacement therapy (HRT) use declined sharply after mid-2002, when the Women's Health Initiative trial reported an association between breast cancer occurrence and HRT. Hypothesized mechanism behind this association is that HRT promotes growth of pre-existing small tumors, leading to earlier tumor detection. We evaluated the impact of the sudden decline in HRT use on age distribution of breast cancer in Geneva. We included all incident breast cancer cases recorded from 1975 to 2006 at the Geneva cancer registry. We calculated mean annual incidence rates per 100,000 for 2year periods for three age groups and assessed temporal changes by joinpoint regression. We compared age-specific incidence curves for different periods, reflecting different prevalence rates of HRT use. After increasing constantly between 1986 and 2002 among women aged 50-69years [annual percent change (APC): +4.4, P<0.0001], rates declined sharply after 2003 (APC: −6.0; P=0.0264). Age-specific breast cancer rates changed dramatically with changes in prevalence of HRT use. During low HRT prevalence, breast cancer incidence increased progressively with age, when HRT prevalence was reaching its maximum (1995-2002), higher rates were seen in 60- to 64-year-old women, with a concomitant decrease in risk among elderly. After the sudden decline in HRT use, the incidence peak diminished significantly and incidence increased again with age. Following the abrupt decline in HRT use in Geneva, breast cancer incidence rates among post-menopausal women decreased considerably with striking changes in age-specific incidence rates before, during and after the peak in HRT prevalenc

Concordance in a World without a Gold Standard: A New Non-Invasive Methodology for Improving Accuracy of Fibrosis Markers

BACKGROUND: Assessing liver fibrosis is traditionally performed by biopsy, an imperfect gold standard. Non-invasive techniques, liver stiffness measurements (LSM) and biomarkers [FibroTest(R) (FT)], are widely used in countries where they are available. The aim was to identify factors associated with LSM accuracy using FT as a non-invasive endpoint and vice versa. METHODS: The proof of concept was taken using the manufacturers recommendations for excluding patients at high risk of false negative/positive. The hypothesis was that the concordance between LSM and FT, would be improved by excluding high-risk patients. Thereafter, the impact of potential variability factors was assessed by the same methods. Liver biopsy and independent endpoints were used to validate the results. RESULTS: Applying manufacturers' recommendations in 2,004 patients increased the strength of concordance between LSM and FT (P<0.00001). Among the 1,338 patients satisfying recommendations, the methodology identified a significant LSM operator effect (P = 0.001) and the following variability factors (all P<0.01), related to LSM: male gender, older age, and NAFLD as a cause of liver disease. Biopsy confirmed in 391 patients these results. CONCLUSION: This study has validated the concept of using the strength of concordance between non-invasive estimates of liver fibrosis for the identification of factors associated with variability and precautions of use