1,205 research outputs found
Diesel spray macroscopic parameter estimation using a synthetic shapes database
The paper presents a method for the macroscopic characterization of diesel sprays starting from digital images. Macroscopic spray characterization mainly consists in the definition of two parameters, namely penetration and cone angle. The latter can be evaluated according to many possible definitions, all based on the spray contour that is obtained by means of image thresholding. Therefore, the obtained cone angle value depends on the adopted angle definition and on the used thresholding algorithm. In order to avoid this double dependence, an alternative method has hence been proposed. The algorithm does not require the image thresholding and has an intrinsic cone angle definition. The algorithm takes advantage of principal component analysis technique and allows for a direct estimation of spray penetration and cone angle by comparing the original image with a database made of artificial spray images. In the present work, images coming from two different experiments are analyzed with the proposed method and results are compared with those obtained with a traditional procedure based on the Otsu's image thresholding and four cone angle definitions. © 2019 by the authors
Loss of Liquid Lithium Coolant in an Accident in a DONES Test Cell Facility
A Demo-Oriented early NEutron Source (DONES) facility for material irradiation with nuclear is currently being designed. DONES aims to produce neutrons with fusion-relevant spectrum and fluence by means of D–Li stripping reactions occurring between a deuteron beam impacting a stable liquid lithium flowing film implementing the target. Given the hazard constituted by the liquid lithium inventory and the potential risk of reactions with water, air, and concrete eventually resulting in fire events, the Target Test Cell (TTC) is filled with helium and the reinforced concrete walls forming the bio-shield are covered with steel liners. A loss of Li in TTC, due to a large break in the Quench Tank, is postulated, and consequences are deterministically studied. With the TTC liner being water-cooled, the impact of the liner temperature rise following a leakage event is evaluated. Two separate MELCOR code models have been defined for the liquid lithium loop and water-cooled loop and are numerically coupled. The amount of leaked inventory dependent on the implemented safety logic and impact on TTC containment is evaluated. The water pressurization pattern within the liner cooling loop is studied to highlight possible risks of lithium–water/concrete reactions
Agressions sexuelles entre adolescents: travail sur la prévention dans les équipes éducatives : enquête sur la fréquence, sur l’ampleur et sur les techniques de prévention des agressions sexuelles entre mineurs, commises en institutions
A travers ce travail de recherche, nous avons mené une réflexion autour des méthodes susceptibles de prévenir les situations d’agressions sexuelles en institution accueillant des adolescents. Pour y parvenir, nous avons tout d’abord développé trois concepts liés à notre sujet de recherche : l’adolescence, les agressions sexuelles et la prévention. Nous avons opté pour une recherche plus approfondie de la prévention secondaire car elle peut s’appliquer auprès d’adolescents vivant en institution. Une fois ces concepts approfondis, nous avons été en mesure de préciser nos trois hypothèses. La première s’intéresse aux outils concrets utilisés par les éducateurs et qui permettent de prévenir les agressions sexuelles. La deuxième hypothèse est liée à l’éventuel tabou présent lorsqu’il s’agit d’aborder le sujet de la sexualité. Quant à la troisième, elle se penche sur les formations suivies par les éducateurs, abordant les thèmes de la sexualité ou des agressions sexuelles. Afin d’obtenir des réponses à ces divers questionnements, nous avons choisi d’interroger six éducatrices et six éducateurs travaillant au sein des institutions suivantes : l’Institut Saint-Raphaël, le Foyer de Salvan et la Fondation Cité-Printemps. Ces trois institutions se situent en Valais et accueillent des adolescents connaissant des difficultés familiales, comportementales, sociales ou scolaires. A savoir que dans chacune de ces institutions, nous avons interrogé quatre professionnels. Les résultats de l’enquête démontrent qu’effectivement peu d’outils matériels sont à disposition des éducateurs sociaux. La collaboration avec le SIPE semble correspondre à l’outil immatériel le plus utilisé par les professionnels. Au niveau du tabou, il apparaît que la moitié des éducateurs interrogés affirment ne ressentir aucun tabou lorsqu’il est question d’aborder le thème de la sexualité. En revanche, nous pouvons noter que si un tabou est présent, les éducateurs éprouvent des difficultés à mettre en place des techniques de prévention auprès des jeunes. Nous avons également pu constater que parmi les éducateurs interrogés, peu d’entre eux ont suivi des formations sur la sexualité des adolescents. De plus, les éducateurs nous ont transmis des pistes d’action intéressantes pour prévenir les agressions sexuelles. De notre côté, nous avons recensé, dans ce travail, des outils concrets et ludiques permettant d’aborder divers thèmes liés à la sexualité. A l’issue des entretiens, de nouvelles idées de prévention nous sont également parvenues : désigner un professionnel de l’équipe éducative devant s’assurer que les thématiques de la sexualité, du genre et du respect soient abordées de manière régulière ; informer les parents quant aux risques liés à internet ; présenter des outils concrets aux éducateurs et transmettre ce travail aux différentes institutions
From Environment to Genome and Back : a Lesson from HFE Mutations
The environment and the human genome are closely entangled and many genetic variations that occur in human populations are the result of adaptive selection to ancestral environmental (mainly dietary) conditions. However, the selected mutations may become maladaptive when environmental conditions change, thus becoming candidates for diseases. Hereditary hemochromatosis (HH) is a potentially lethal disease leading to iron accumulation mostly due to mutations in the HFE gene. Indeed, homozygosity for the C282Y HFE mutation is associated with the primary iron overload phenotype. However, both penetrance of the C282Y variant and the clinical manifestation of the disease are extremely variable, suggesting that other genetic, epigenetic and environmental factors play a role in the development of HH, as well as, and in its progression to end-stage liver diseases. Alcohol consumption and dietary habits may impact on the phenotypic expression of HFE-related hemochromatosis. Indeed, dietary components and bioactive molecules can affect iron status both directly by modulating its absorption during digestion and indirectly by the epigenetic modification of genes involved in its uptake, storage and recycling. Thus, the premise of this review is to discuss how environmental pressures led to the selection of HFE mutations and whether nutritional and lifestyle interventions may exert beneficial effects on HH outcomes and comorbidities
Nutrition and genetics in NAFLD : The perfect binomium
Nonalcoholic fatty liver disease (NAFLD) represents a global healthcare burden since it is epidemiologically related to obesity, type 2 diabetes (T2D) and Metabolic Syndrome (MetS). It embraces a wide spectrum of hepatic injuries, which include simple steatosis, nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis and hepatocellular carcinoma (HCC). The susceptibility to develop NAFLD is highly variable and it is influenced by several cues including environmental (i.e., dietary habits and physical activity) and inherited (i.e., genetic/epigenetic) risk factors. Nonetheless, even intestinal microbiota and its by-products play a crucial role in NAFLD pathophysiology. The interaction of dietary exposure with the genome is referred to as \u2018nutritional genomics,\u2019 which encompasses both \u2018nutrigenetics\u2019 and \u2018nutriepigenomics.\u2019 It is focused on revealing the biological mechanisms that entail both the acute and persistent genome-nutrient interactions that influence health and it may represent a promising field of study to improve both clinical and health nutrition practices. Thus, the premise of this review is to discuss the relevance of personalized nutritional advices as a novel therapeutic approach in NAFLD tailored management
DEMO divertor cassette and plasma facing unit in vessel loss-of-coolant accident
As part of the pre-conceptual design activities for the European DEMOnstration plant, a carefully selected set of safety analyses have been performed to assess plant integrated performance and the capability to achieve expected targets while keeping it in a safe operation domain. The DEMO divertor is the in-vessel component in charge of exhausting the major part of the plasma ions' thermal power in a region far from the plasma core to control plasma pollution. The divertor system accomplishes this goal by means of assemblies of cassette and target plasma facing units modules, respectively cooled with two independentheat-transfer systems. A deterministic assessment of a divertor in-vessel Loss-of-Coolant Accident is here considered. Both Design Basis Accident case simulating the rupture of an in-vessel pipe for the divertor cassette cooling loop, and a Design Extension Conditions accident case considering the additional rupture of an independent divertor target cooling loop are assessed. The plant response to such accidents is investigated, a comparison of the transient evolution in the two cases is provided, and design robustness with respect to safety objectives is discussed
The SOD2 C47T polymorphism influences NAFLD fibrosis severity: evidence from case-control and intra-familial allele association studies.
AIMS:
Non-alcoholic fatty liver disease (NAFLD) is a complex disease trait where genetic variations and environment interact to determine disease progression. The association of PNPLA3 with advanced disease has been consistently demonstrated but many other modifier genes remain unidentified. In NAFLD, increased fatty acid oxidation produces high levels of reactive oxygen species. Manganese-dependent superoxide dismutase (MnSOD), encoded by the SOD2 gene, plays an important role in protecting cells from oxidative stress. A common non-synonymous polymorphism in SOD2 (C47T; rs4880) is associated with decreased MnSOD mitochondrial targeting and activity making it a good candidate modifier of NAFLD severity.
METHODS:
The relevance of the SOD2 C47T polymorphism to fibrotic NAFLD was assessed by two complementary approaches: we sought preferential transmission of alleles from parents to affected children in 71 family trios and adopted a case-control approach to compare genotype frequencies in a cohort of 502 European NAFLD patients.
RESULTS:
In the family study, 55 families were informative. The T allele was transmitted on 47/76 (62%) possible occasions whereas the C allele was transmitted on only 29/76 (38%) occasions, p=0.038. In the case control study, the presence of advanced fibrosis (stage>1) increased with the number of T alleles, p=0.008 for trend. Multivariate analysis showed susceptibility to advanced fibrotic disease was determined by SOD2 genotype (OR 1.56 (95% CI 1.09-2.25), p=0.014), PNPLA3 genotype (p=0.041), type 2 diabetes mellitus (p=0.009) and histological severity of NASH (p=2.0Ă—10(-16)).
CONCLUSIONS:
Carriage of the SOD2 C47T polymorphism is associated with more advanced fibrosis in NASH
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