Analyse morphologique des champs de cavités dans un élastomère sous décompression d'hydrogène : Influence des conditions de décompression et effets d'interaction

The morphology of cavitation is analyzed in an unfilled EPDM under different hydrogen decompression conditions. The experimental device allows a time-resolved tracking of the evolution of damage. Images are processed to obtain the onset time, the number and sizedistribution of cavities over time, and the inflation / deflation kinetics of the biggest cavities.Covariograms quantifies the spatial distribution of cavity fields. The analysis is thus led at two scales: that of independent cavities and that of the full cavity fields. At the cavity scale, kineticsis shown to be identical for independent cavities but different between inflation and deflation.Experimental kinetics is compared to that issued from Finite Element calculations in a cell containing one or two cavities, in coupled diffuso-mechanical conditions. Calculationshighlight the evolution of local mechanical and gas content fields, as well as interaction effects between close cavities. At the scale of cavity fields, the spatial distribution is influenced by the decompression conditions. The number and size of cavities increase with saturation pressure and/or decompression rate and a second population of small cavities is nucleated around the first one under severe decompression conditions. The homogeneity and isotropy of the distribution at macroscopic scale are studied. The influence of cycling on the evolution of cavitation morphology is addressed in the final part. It was finally found that the morphology of cavity fields evolves during successive cycles. The analysis provides information to discuss and to inquire the framework and ingredients of damage models.La morphologie de l’endommagement par cavitation est analysée dans un EPDM non chargé sous différentes conditions de décompression d’hydrogène. Les expériences permettent devisualiser l’évolution de l’endommagement au cours du temps. Les images obtenues sont traitées pour obtenir l’instant d’apparition, le nombre et la distribution de taille des cavités au cours du temps. Elles permettent également de suivre les cinétiques de croissance / décroissance des plus grosses cavités. Le tracé de covariogrammes permet de quantifier la distribution spatiale de ces cavités. L’analyse de cet ensemble de données porte donc sur deux échelles :celle de cavités indépendantes et celle de champs de cavités. A l’échelle de la cavité, les cinétiques expérimentales sont corrélées à des calculs numériques par Eléments Finis en conditions diffuso-mécaniques couplées sur une cellule élémentaire contenant une ou deuxcavité(s). Ces calculs permettent par ailleurs d’éclairer les évolutions locales des champs mécaniques et de concentration de gaz, ainsi que les mécanismes d’interaction entre cavités voisines. Les covariogrammes fournissent des éléments pour estimer les caractéristiques d’un Volume Elémentaire Représentatif (VER) (taille, isotropie) et discuter la représentativité d’untel modèle numérique selon les conditions de décompression. A l’échelle des champs de cavités,les conditions de décompression influencent la répartition spatiale. Le nombre et la taille des cavités augmentent avec la pression de saturation et/ou la vitesse de décompression, et une seconde population de petites cavités apparaît autour des premières sous conditions sévères.L’homogénéité et l’isotropie de la distribution à l’échelle macroscopique sont étudiées. Il est finalement montré que la morphologie des champs de cavités évolue au cours de cycles successifs. Cette analyse fournit des informations pour discuter et renseigner le cadre et les ingrédients de modèles d’endommagement

Heterologous Expression of Wheat VERNALIZATION 2 (TaVRN2) Gene in Arabidopsis Delays Flowering and Enhances Freezing Tolerance

The vernalization gene 2 (VRN2), is a major flowering repressor in temperate cereals that is regulated by low temperature and photoperiod. Here we show that the gene from Triticum aestivum (TaVRN2) is also regulated by salt, heat shock, dehydration, wounding and abscissic acid. Promoter analysis indicates that TaVRN2 regulatory region possesses all the specific responsive elements to these stresses. This suggests pleiotropic effects of TaVRN2 in wheat development and adaptability to the environment. To test if TaVRN2 can act as a flowering repressor in species different from the temperate cereals, the gene was ectopically expressed in the model plant Arabidopsis. Transgenic plants showed no alteration in morphology, but their flowering time was significantly delayed compared to controls plants, indicating that TaVRN2, although having no ortholog in Brassicaceae, can act as a flowering repressor in these species. To identify the possible mechanism by which TaVRN2 gene delays flowering in Arabidopsis, the expression level of several genes involved in flowering time regulation was determined. The analysis indicates that the late flowering of the 35S::TaVRN2 plants was associated with a complex pattern of expression of the major flowering control genes, FCA, FLC, FT, FVE and SOC1. This suggests that heterologous expression of TaVRN2 in Arabidopsis can delay flowering by modulating several floral inductive pathways. Furthermore, transgenic plants showed higher freezing tolerance, likely due to the accumulation of CBF2, CBF3 and the COR genes. Overall, our data suggests that TaVRN2 gene could modulate a common regulator of the two interacting pathways that regulate flowering time and the induction of cold tolerance. The results also demonstrate that TaVRN2 could be used to manipulate flowering time and improve cold tolerance in other species

Prevalence et facteurs associes a l’halitose buccale : Etude dans une population generale senegalaise

Introduction: Halitosis is a common complain among dental patients, chronic among 50% of the adult population, and of oral origin in 90% of the cases. The objective of this study was to evaluate the prevalence and related factors of oral halitosis among a senegalese population. Material and method: This was a transversal descriptive study of 396 Senegalese adults using a 24-point self-assessment questionnaire on halitosis. All subjects were examined to estimate the organoleptic means and to measure the Sulfur Volatile Compounds (SVC), using a halimeter. Halitosis was diagnosed when the level of sulfur volatile Compound was ≥125 ppb and the organoleptic score ≥ 2. Data were statistically analyzed using the chi2 test. Results: The global prevalence of halitosis was 32.3 %. The difference was not statistically significant between male and female. Among the 396 patients suffering from bad breath, 128 had a permanent halitosis and 52 had a physiological halitosis. The means of the organoleptic scores were 3.12 and that of the (SVC) were 273.9 ppb. Conclusion: The results of the study showed a relation between the organoleptic tests and the level of sulfur volatile compounds (SVC). Keywords: Halitosis, organoleptic tests, sulfur volatile compound, epidemiology, and self-assessment

Inflammatory breast cancer: features and outcomes in a breast unit in Dakar, Senegal

Background: The aim of this study was to determine clinical features and outcomes of patients with inflammatory breast cancer (IBC) treated in our breast unit.Methods: This study was performed at Gynaecologic and Obstetric Clinic of Dakar Teaching Hospital, in which a breast unit was created since 2007. All women with diagnosis of inflammatory breast cancer in our Breast Unit between January 2010 and December 2013 were included in this study. The diagnosis of IBC was made clinically using the American Joint Committee on Cancer (AJCC) and confirmed histologically. The follow-up cut-off for this data set was December 31st, 2014. All analyses for this study were performed using SPSS software (version 20.0).Results: Between 2010 and 2013, 22 women with breast cancer who met eligibility criteria were included out of 161 patients followed for breast cancer leading to a frequency of 13.6%. The median age at diagnosis was 43.4 years (26-79 years). Mean time to diagnosis was 4 months. The mean time to recurrence was 11.2 months. This recurrence was observed in 45.5% of cases. The median overall survival was 13.3 months (CI 95% 8.576-18.526), the survival rate was 31.8%.Conclusions: This series shows a high frequency of inflammatory breast cancer. These tumours are very aggressive with a very poor prognosis

Dyslipidemia, obesity and other cardiovascular risk factors in the adult population in Senegal

Introduction: According to the WHO, 50% of deaths worldwide (40.1% in developing countries) are due to chronic non-communicable diseases (NCDs). Of these chronic NCDs, cardiovascular diseases remain the leading cause of death and disability in developed countries. The Framingham study has shown the importance of hypercholesterolemia as a primary risk factor. In Senegal, the epidemiology of  dyslipidemia and obesity are still poorly understood due to the lack of comprehensive studies on their  impact on the general population. This motivated this study to look into the key epidemiologic and socio-demographic determinants of these risk factors. Methods: It was a cross-sectional descriptive epidemiological survey which included 1037 individuals selected by cluster sampling. Data were collected using a questionnaire following the WHO STEPwise approach. Socio-demographic, health and biomedical variables were collected. P value Results: The average age was 48 years with a female predominance (M: F of 0.6). The literacy rate was 65.2% and 44.7% of participants were from rural areas. The prevalence of hypercholesterolemia, hyperLDLemia, hypoHDLemia, hypertriglyceridemia and mixed hyperlipidemia were 56%, 22.5%, 12.4%, 7.11% and 1.9% respectively. One in four was obese (BMI> 30kg/m2) and 34.8% had abdominal obesity. The main factors significantly associated with dyslipidemia were obesity, urban dwelling, physical inactivity and a family history of dyslipidemia. Conclusion: The prevalence of dyslipidemia, obesity and other risk factors in the population was high needing immediate care for those affected and implementation of prevention strategies.Key words: Dyslipidemia, obesity, cardiovascular, risk factors, Saint Loui

Lipid profile frequency and the prevalence of dyslipidaemia from biochemical tests at Saint Louis University Hospital in Senegal

Introduction: The aim of this study was to evaluate the frequency of lipid profile requests and the  prevalence of dyslipidemia in patients at the biochemistry laboratory of St. Louis University Hospital, as well as their correlation with sex and age. Methods: This was a retrospective study reviewing 14,116  laboratory results of patients of both sexes, over a period of six months (January-June 2013) regardless of the indication for the request. The lipid parameters included were: Total cholesterol, HDL-cholesterol, LDL-cholesterol, trig lycerides with normal values defined as follows: Total cholesterol (<2g/l), HDL- cholesterol (>0,40g/l), LDL- cholesterol (<1,30g/l) and Triglycerides (<1,50g/l). Results: The average age of our study population was 55.15 years with a female predorminance (M/F=0.60). The age group most represented was that between 55-64 years. The frequency of lipid profile request in our sample was 9.41% (or 1,329). The overall prevalence of isolated hypercholesterolemia, hyperLDLaemia,  hypoHDLaemia, hypertriglyceridaemia, and mixed hyperlipidemia were respectively 60.91%, 66.27%, 26.58%, 4.57% and 2.75%. Hypercholesterolemia, hyperLDLaemia, hypertriglyceridaemia and mixed hyperlipidaemia were higher in women with respectively 66.22%, 67.98%, 4.58%, 2.89% than in men (52.01%, 62.81%, 4.44% and 2.40% respectively). On the other hand, the prevalence of hypoHDLaemia was higher in males (32.19%) compared to females (23.76%). Hypercholesterolemia correlated  significantly with age and sex. Conclusion: Our study showed a relatively low request rate for lipid profile and a high prevalence of dyslipidaemia hence the importance of conducting a major study on the prevalence of dyslipidaemia and associated factors in the Senegalese population.Key words: Lipid profile, dyslipidaemia, prevalence, Senega

Pauvreté et accès à l'eau dans la vallée du Sénégal

Water poverty in the Senegal Valley Considering the flood-recession agriculture, the hydraulic history of the valley of the Senegal River is ancient, but knows a deep mutation since the introduction of the irrigation. Can one speak of water poverty, whereas two dams now control the water flow of the Senegal River and ensure a permanent abundance in water ? The answer to this questioning is proposed through the link between poverty, access to funding, access to land, and involvement in resource management.L'histoire hydraulique de la vallée du fleuve Sénégal est ancienne et remonte à la culture de décrue. Mais elle connaît une profonde mutation depuis l'introduction de l'irrigation. Peut-on parler de « pauvreté hydraulique », alors que deux barrages régulent à présent le régime du fleuve Sénégal et assurent une permanence de l'abondance en eau ? La réponse à cette question est proposée sous l'angle de l'articulation entre la pauvreté, l'accès au financement, l'accès au foncier, la participation à la gestion de la ressource

Rapid susceptibility testing of Mycobacterium tuberculosis by the Mycobacteria Growth Indicator Tube (MGITAST SIRE)

ObjectiveTo evaluate the reliability of the Mycobacteria Growth Indicator Tube (MGITAST) for susceptibility testing of Mycobacterium tuberculosis.MethodsSeventy strains of M. tuberculosis were tested for susceptibility to streptomycin, isoniazid, rifampicin and ethambutol by comparing MGITAST results to those obtained by the method of proportion (MOP) on Lowenstein–Jensen (LJ) and Middlebrook 7H10 media. The 7H10 MOP was considered the method of reference.ResultsThe turnaround time for MGITAST was 6.2days (5–10days) and for MOP it was 18–21days. With rifampicin, MGITAST agreed for all isolates with both MOP. For streptomycin, MGITAST and 7H10 MOP agreed for 64 isolates (91.4%); 61 were susceptible and three resistant. LJ MOP and 7H10 MOP agreed for 64 isolates (92.2%); 62 were susceptible and three resistant. With isoniazid, both MOP agreed for all isolates, while MGITAST and 7H10 MOP had two discrepancies. For ethambutol, MGITAST and 7H10 MOP were concordant for 66 isolates; 65 were susceptible and one resistant. Both MOP were concordant for 67 isolates; 66 were susceptible and one resistant.ConclusionsBased on these results, MGITAST is a time-saving method and can be used as an alternative to the BACTEC System. MGITAST is reliable as far as rifampicin and isoniazid are concerned; however, additional studies are needed for streptomycin and ethambutol

Les traumatismes vertebro-medullaires par chute de la hauteur d’un arbre a propos de 73 cas au Mali.

Introduction Les chutes du haut d’un arbre sont des accidents graves et fréquents au MALI.Objectif Analysez les facteurs épidémiologiques, étiologiques et circonstanciels des chutes de la hauteur des arbres Matériels et méthodes Il s’agit d’une étude prospective continue d’octobre 2007 à septembre 2009 à l’hôpital Gabriel Touré de Bamako (Mali). Elle a concerné tous les cas de chute du haut d’un arbre pendant cette période.Résultats Au cours de cette étude, nous avons recensé 73 patients dont les âges étaient compris entre 5 et 65 ans. Les couches socioprofessionnelles les plus atteintes ont été les cultivateurs et les bergers aux conditions socioéconomiques défavorables. Pendant les mois de décembre à mai 79,45% (58 patients) des patients ont été enregistrés. Cette période correspondait à la traite des fruits et à la saison sèche avec le manque de pâturages pour les animaux. L’intervention chirurgicale a concerné 32 patients. La mortalité a été de 12,32% (9 patients) tous traumatisés cervicaux.Conclusions Les accidents par chutes d’arbres sont en rapport avec les conditions socio-économiques et climatiques au Mali.Mots clés : Arbre, Accident, Chute, Mali, Rachis, Traumatism