Diseño mecánico conceptual de rotores para centrífugas.

En la actualidad casi la totalidad de los reactores nucleares necesitan, como combustible, uranio con una concentración de U"235 mayores a las naturales. En un marco de autoabastecimiento se impone la necesidad de dominar la tecnología necesaria para enriquecer uranio, siendo las centrifugas el método usado industrialmente hoy en día. Esta tecnología, por cuestiones de proliferación, es considerada sensitiva y en consecuencia la información sobre la misma se encuentra fuertemente limitada. En el presente trabajo se propone un modelo simplificado para diseñar y evaluar conceptualmente diseños mecánicos de rotores, proponiendo como figura de merito el trabajo separativo para centrifugas de gas. Con el mismo se pudo, evaluando distintos materiales para el rotor, encontrar radios y alturas óptimos para la capacidad separativa por unidad de masa para cada uno de ellos. Se evaluaron los parámetros que definen la recirculación interna del flujo dentro del rotor y los parámetros de diseño mecánico. Al comparar los resultados con los disponibles en bibliografía se vio que presentan buena concordancia mecánica.

SNP technologies for drug discovery : a current review

Single nucleotide polymorphisms (SNPs) are unique genetic differences between individuals that contribute in significant ways to the determination of human variation including physical characteristics like height and appearance as well as less obvious traits such as personality, behaviour and disease susceptibility. SNPs can also significantly influence responses to pharmacotherapy and whether drugs will produce adverse reactions. The development of new drugs can be made far cheaper and more rapid by selecting participants in drug trials based on their genetically determined response to drugs. Technology that can rapidly and inexpensively genotype thousands of samples for thousands of SNPs at a time is therefore in high demand. With the completion of the human genome project, about 12 million true SNPs have been identified to date. However, most have not yet been associated with disease susceptibility or drug response. Testing for the appropriate drug response SNPs in a patient requiring treatment would enable individualised therapy with the right drug and dose administered correctly the first time. Many pharmaceutical companies are also interested in identifying SNPs associated with polygenic traits so novel therapeutic targets can be discovered. This review focuses on technologies that can be used for genotyping known SNPs as well as for the discovery of novel SNPs associated with drug response.

A longitudinal study comparing bereavement phenomena in recently bereaved spouses, adult children and parents

Objective: The study investigated previous research findings and clinical impressions which indicated that the intensity of grief for parents who had lost a child was likely to be higher than that for widows/widowers, who in turn were likely to have more intense reactions than adult children losing a parent. Method: In order to compare the intensities of the bereavement reactions among representative community samples of bereaved spouses (n = 44), adult children (n = 40) and parents (n = 36), and to follow the course of such phenomena, a detailed Bereavement Questionnaire was administered at four time points over a 13-month period following the loss. Results: Measures based on items central to the construct of bereavement showed significant time and group differences in accordance with the proposed hypothesis. More global items associated with the construct of resolution showed a significant time effect, but without significant group differences. Conclusions: Evidence from this study supports the hypothesis that in non-clinical, community-based populations the frequency with which core bereavement phenomena are experienced is in the order: bereaved parents bereaved spouses bereaved adult children.