Modularisation épistatique des loci à trait quantitatif associés à la pression artérielle et identification de gènes candidats pour l’hypertension

Problématique: L’hypertension artérielle essentielle, facteur de risque majeur dans le développement des maladies cardiovasculaires, est un trait multigénique complexe dont les connaissances sur le déterminisme génétique nécessitent d’être approfondies. De nombreux loci à trait quantitatif (QTLs); soit des gènes responsables de faire varier la pression artérielle (PA), ont été identifiés chez l’humain et le modèle animal. Cependant, le mystère plane encore sur la façon dont ces gènes fonctionnent ensemble pour réguler la PA. Hypothèse et objectif: Plutôt qu’une addition de QTLs ayant chacun une action infinitésimale sur la PA, une interaction épistatique entre les gènes serait responsable du phénotype hypertendu. Ainsi, l’étude de cette épistasie entre les gènes impliqués, directement ou indirectement, dans l’homéostasie de la PA nous permettrait d’explorer de nouvelles voies de régulation moléculaire en cause dans cette maladie. Méthodes: Via la réalisation de souches congéniques de rats, où un segment chromosomique provenant d’une souche receveuse hypertendue (Dahl Salt Sensitive, SS/Jr) est remplacé par son homologue provenant d’une souche donneuse normotendue (Lewis, LEW), des QTLs peuvent être mis en évidence. Dans ce contexte, la combinaison de QTLs via la création de doubles ou multiples congéniques constitue la première démonstration fonctionnelle des interactions intergéniques. Résultats: Vingt-sept combinaisons au total nous ont menés à l’appréciation d’une modularisation des QTLs. Ces derniers ont été catégorisés selon deux principaux modules épistatiques (EMs) où les QTLs appartenant à un même EM sont épistatiques entre eux et participent à une même voie régulatrice. Les EMs/cascades agissent alors en parallèle pour réguler la PA. Grâce à l’existence de QTLs ayant des effets opposés sur la PA, nous avons pu établir l’ordre hiérarchique entre trois paires de QTLs. Cependant, lorsque cette suite régulatrice ne peut être déterminée, d’autres approches sont nécessaires. Nos travaux nous ont mené à l’identification d’un QTL situé sur le chromosome 16 du rat (C16QTL), appartenant au EM1 et qui révélerait une nouvelle voie de l’homéostasie de la PA. Le gène retinoblastoma-associated protein 140 (Rap140)/family with sequence similarity 208 member A (Fam208a), présentant une mutation non synonyme entre SS/Jr et LEW est le gène candidat le plus plausible pour représenter C16QTL. Celui-ci code pour un facteur de transcription et semblerait influencer l’expression de Solute carrier family 7 (cationic amino acid transporter, y+ system) member 12 (Slc7a12), spécifiquement et significativement sous exprimé dans les reins de la souche congénique portant C16QTL par rapport à la souche SS/Jr. Rap140/Fam208a agirait comme un inhibiteur de la transcription de Slc7a12 menant à une diminution de la pression chez Lewis. Conclusions: L’architecture complexe de la régulation de la PA se dévoile mettant en scène de nouveaux acteurs, pour la plupart inconnus pour leur implication dans la PA. L’étude de la nouvelle voie de signalisation Rap140/Fam208a - Slc7a12 nous permettra d’approfondir nos connaissances quant à l’homéostasie de la pression artérielle et de l’hypertension chez SS/Jr. À long terme, de nouveaux traitements anti-hypertenseurs, ciblant plus d’une voie de régulation à la fois, pourraient voir le jour.

Élaboration d’un modèle de gestion de risques pour le transfert des technologies médicales dans le nouveau bâtiment du projet de modernisation au CHU Sainte-Justine.

Rapport de stage présenté à la Faculté de médecine en vue de l'obtention du grade de Maître ès sciences appliquées (M.Sc.A.) en génie biomédical, option génie clinique.

L’exploration du modèle des vies saines auprès de détenus dans un milieu de réinsertion sociale encadré par un modèle de gestion du risque.

Rapport de stage présenté à la Faculté des arts et des sciences en vue de l'obtention du grade de Maîtrise (M. Sc.) en criminologie option intervention.

Critique du modèle neurophysiologique de la desphinothérapie. Sonophorèse et écholocation.

Un certain nombre de chercheurs (Birch, 1996; Cole, 1995, 1996; De Bergerac, 1998) fondent sur un modèle neurophysiologique leurs arguments en faveur de la delphinothérapie pour traiter divers désordres (DSM-IV) cognitifs et émotifs chez les enfants et les jeunes. Ce modèle recourt à des analogies avec les mécanismes de sonophorèse, d'écholocation et de transmission neurohormonale dans son application thérapeutique. Dans le but de démystifier les éléments pseudo-scientifiques auprès d'un lectorat non spécialisé, cet article critique les postulats et les implications relatifs à ces mécanismes et il conclut à l'absence d'un soutien pertinent et valide concernant ce modèle.

Effect of Dietary Proteins on Growth, Food Conversion and Digestive Enzyme Activity of Juvenile Macrobrachium Rosenbergii

School of Industrial Fisheries, Cochin University of Science and Technology

“Studies on glucose tolerant β-glucosidases from a novel Byssochlamys fulva and their applications in biomass to ethanol conversion”

Beta-glucosidases are critical enzymes in biomass hydrolysis process and is important in creating highly efficient enzyme cocktails for the bio-ethanol industry. Among the two strategies proposed for overcoming the glucose inhibition of commercial cellulases, one is to use heavy dose of BGL in the enzyme blends and the second is to do simultaneous saccharification and fermentation where glucose is converted to alcohol as soon as it is being generated. While the former needs extremely high quantities of enzyme, the latter is inefficient since the conditions for hydrolysis and fermentation are different. This makes the process technically challenging and also in this case, the alcohol generation is lesser, making its recovery difficult. A third option is to use glucose tolerant β-glucosidases which can work at elevated glucose concentrations. However, there are very few reports on such enzymes from microbial sources especially filamentous fungi which can be cultivated on cheap biomass as raw material. There has been very less number of studies directed at this, though there is every possibility that filamentous fungi that are efficient degraders of biomass may harbor such enzymes. The study therefore aimed at isolating a fungus capable of secreting glucose tolerant β- glucosidase enzyme. Production, characterization of β-glucosidases and application of BGL for bioethanol production were attempted.

Studies on fish waste management practices in Aroor Seafood Industrial Belt, Kerala and conversion of seafood waste into a liquid plant growth supplement

This study was materialized to analyze the management issues regarding the seafood processing waste generated including its impact on the coastal community in one of the important seafood hubs of India Aroor Seafood Industrial Belt Alappuzha District Kerala The area has witnessed serious pollution issues related to seafood waste and seldom has any action been implemented by either the polluters or the preventers Further this study is also intended to suggest a low cost eco friendly method for utilizing the bulk quantity of seafood solid waste generated in the area for the promotion of organic farming The high nutritional value of seafood enables the subsequent offal to be considered as an excellent source for plant nutrition The liquid silage accepted worldwide as the cheapest and practical solution for rendering fish waste in bulk for production of livestock feed is adopted in this study to develop foliar fertilizer formulations from various seafood waste The effect of seafood foliar sprays is demonstrated by field studies on two plant varieties such as Okra and Amaranthus

Factors influencing a conversion to organic farming in Nepalese tea farms

Organic agriculture in developing countries has increased in past decades especially due to the high demand of organic products in developed countries. The rate of conversion to organic production in Nepal, however, is observed much slower than expected. This study investigates factors that determine the conversion to organic production using Nepalese tea producers as a case study. A survey of 181 farmers was conducted in the Ilam and Panchthar district of Nepal, among which 86 were organic farmers and 95 were conventional farmers. A discriminant analysis was used to identify socio-economic characteristics that distinguish conventional and organic farmers. Results from the estimated discriminant function suggest that farmers located in a distance from regional markets, older in age, better trained, affiliated with institutions and having larger farms are more likely to adopt organic production. Similarly, a factor analysis shows that environmental awareness, bright market prospects, observable economic benefit and health consciousness are the major factors influencing farmers’ decisions on the conversion to organic production. While planning programs for the development of the organic tea sector in Nepal, policy makers should consider the support of farmers’ institutions, provision of training to farmers and raise farmers’ awareness about the environmental, economic and health benefits of organic farming.

Effects of grassland conversion and tillage intensities on soil microbial biomass, residues and community structure

Agricultural intensification has a strong impact on level of soil organic matter (SOM), microbial biomass stocks and microbial community structure in agro-ecosystems. The size of the microbial necromass C pool could be about 40 times that of the living microbial biomass C pool in soils. Due to the specificity, amino sugar analysis gives more important information on the relative contribution of fungal and bacterial residues to C sequestration potential of soils. Meanwhile, the relationship between microbial biomass and microbial necromass in soil and its ecological significance on SOM are not fully understood and likely to be very complex in grassland soils. This thesis focuses on the effects of tillage, grassland conversion intensities and fertilisation on microbial biomass, residues and community structure. The combined analyses of microbial biomass and residue formation of both fungi and bacteria provided a unique opportunity to study the effect of tillage, grassland conversion and fertilisation on soil microbial dynamics. In top soil at 0-30 cm layer, a reduction in tillage intensity by the GRT and NT treatments increased the accumulation of saprotrophic fungi in comparison with the MBT treatment. In contrast, the GRT and NT treatments promoted AMF at the expense of saprotrophic fungi in the bottom soil layer at 30-40 cm depth. The negative relationship between the ergosterol to microbial biomass C ratio and the fungal C to bacterial C ratio points to the importance of the relationship between saprotrophic fungi and biotrophic AMF for tillage-induced changes in microbial turnover of SOC. One-season cultivation of winter wheat with two tillage events led to a significant loss in SOC and microbial biomass C stocks at 0-40 cm depth in comparison with the permanent grassland, even 5 years after the tillage event. However, the tillage induced loss in microbial biomass C was roughly 40% less in the long-term than in the short-term of the current experiment, indicating a recovery process during grassland restoration. In general, mould board tillage and grassland conversion to maize monoculture promoted saprotrophic fungi at the expense of biotrophic AMF and bacteria compared to undisturbed grassland soils. Slurry application promoted bacterial residues as indicated by the decreases in both, the ergosterol to microbial biomass C ratio and the fungal C to bacterial C ratio. In addition, the lost microbial functional diversity due to tillage and maize monoculture was restored by slurry application both in arable and grassland soils. I conclude that the microbial biomass C/S ratio can be used as an additional indicator for a shift in microbial community. The strong relationships between microbial biomass and necromass indices points to the importance of saprotrophic fungi and biotrophic AMF for agricultural management induced effects on microbial turnover and ecosystem C storage. Quantitative information on exact biomass estimates of these two important fungal groups in soil is inevitably necessary to understand their different roles in SOM dynamics.

Nanostructures and energy conversion

The unique properties of nanostructures associated with their low dimensionality give rise to new opportunities for research on nanoscale heat transfer and energy conversion. Inspired by Majumdar’s analysis of the novel aspects of heat, mass, and charge flow across the interface between hard and soft materials, some perspectives about research frontiers in nanoscale heat transfer and energy conversion are provided.

Caracterización de un modelo de gestión del conocimiento aplicable a las funciones universitarias de investigación y extensión: caso Universidad CES

Existen en la actualidad múltiples modelos de gestión de conocimiento y medición del capital humano, los cuales son aplicados en las organizaciones, pero ninguno de éstos ha sido diseñado para Instituciones de Educación Superior. En este trabajo se hace un recuento de algunos de los modelos de gestión del conocimiento y capital intelectual más destacados como el Modelo de conversión del conocimiento de Nonaka y Takeuchi, el Modelo de GC de Arthur Andersen, el Cuadro de Mando Integral de Kaplan y Norton, entre otros, pero es a partir del Modelo Organizacional Estrella de Galbraith que se presenta una propuesta teórica para caracterizar un modelo de gestión del conocimiento aplicable a las funciones universitarias de investigación y extensión en la Universidad CES – Medellín, Colombia, a través de una investigación cualitativa en donde, a partir de la correlación entre la teoría general de la GC, particularmente de los modelos y el análisis de las características de la Universidad CES, así como la revisión sistemática, el grupo focal y el análisis documental se propone el Modelo Hexagonal de GC.

Pediatric conversion to the HiResolution processing strategy: 6 case studies

This paper presents a study documenting the general trends in the programming techniques, aided behavioral thresholds, speech perception abilities, and overall behavior when converting children into processing strategy called HiResolution (HiRes), used with the Advanced Bionics Clarion II Cochlear Implant System.