2,011 research outputs found

    An experimental study of separation of binary and ternary gas mixtures by parametric pumping

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    An experimental study of gas parametric pumping is presented which examines the purification of helium using silica gel to remove the impurity carbon dioxide. Low gas flow rates are used to allow adequate time for equilibrium to be approached, assuming intraparticle diffusion is the controlling mass transfer step. By varying the cycle time, at long cycle times, the effect of penetration length (a function of dynamic capacity) is indicated. Also, at low cycle time, the effects during pressure changes become more significant. Using low flow rate improves separation effectiveness if evaluated at equal dynamic capacity. When using low flow rate and low cycle time, the gas added during repressuring and removed during blowdown should be used in calculating the purge to feed ratio. If this is not used then the purge concentration calculation method will not be accurate. When operating under conditions where the repressurizing gas makes up a large percentage of the gas fed, a poor separation efficiency resulted, due to inadequate regeneration of the purging column. The system helium, carbon dioxide, and propylene was evaluated at higher flow rate. Adsorbtion breakthrough curves from adding carbon dioxide and propylene simultaneously to silica gel showed the system to be non-ideal. The carbon dioxide adsorbed to a peak level and then desorbed as additional propylene adsorbed. Using this system, even though more propylene can adsorb than carbon dioxide, the separation of carbon dioxide was more effective than propylene. This apparent departure from theory may be due to insufficient time for the more strongly adsorbed propylene to purge from the column

    Critical Housing Finance Challenges for Policy Makers

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    Examines barriers for mortgage lending to underserved groups and in distressed neighborhoods, such as risk assessment; financing for multifamily rental markets, such as affordability; and financing for sustainable housing, such as transactional costs

    Torus Palatinus: A New Anatomical Correlation with Bone Density in Postmenopausal Women

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    The observation that subjects who have a striking oral exostosis, called torus palatinus, also tended to have normal or high bone densities prompted us to examine an unselected population referred for bone density assessment for a possible correlation with torus palatinus. Subjects referred from community physicians had a visual examination of the open mouth to estimate the size of any torus palatinus (0 for none/ trace to 5 for very large) before undergoing a bone density measurement by dual energy x-ray absortiometry. Bone density T- and z-scores were correlated with the size of each subject’s torus palatinus. Torus size groups were also correlated with other variables affecting bone density. About 20% of 370 postmenopausal female subjects,\u3e90% Caucasian, had a moderate to large torus palatinus. Regression correlations for torus size were modest, but significantly related to T- and z-scores of lumbar vertebrae and left hip (P \u3c 0.01 for each). Differences due to medication, body mass index, smoking, parity, and several other factors that affect bone density did not diminish the relation to torus size. This study shows a small, but significant, positive relation for postmenopausal, Caucasian women between bone mineral density and torus size after controlling for several variables known to affect bone density were examined. Torus prominence, in association with other factors, can be considered in decisions for testing bone density in otherwise normal postmenopausal women

    Investigation of the effect of combined thermomechanical processing on the brass microstructure evolution and the microhardness change

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    The article investigates the effect of combined thermomechanical processing, including pre-heat treatment and radial-shear rolling on the brass microstructure evolution and the microhardness change. The microstructure analysis of heat-treated samples according to various modes showed that the most optimal heat treatment before radialshear rolling for L63 brass is annealing at a temperature of 500 °C. As a result of combined thermomechanical processing, a gradient structure was obtained, so in the resulting rods with a diameter of 16 mm in the surface layer, a structure with an average grain size of 9 μm was obtained. In rods with a diameter of 12 mm, a fine–grained, equalgrained structure of 3 μm was obtained in the surface layer

    Bullying victimisation and risk of self harm in early adolescence: longitudinal cohort study

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    Objectives To test whether frequent bullying victimisation in childhood increases the likelihood of self harming in early adolescence, and to identify which bullied children are at highest risk of self harm

    Differential susceptibility to plasticity: a 'missing link' between gene-culture co-evolution and neuropsychiatric spectrum disorders?

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    Brüne's proposal that erstwhile 'vulnerability' genes need to be reconsidered as 'plasticity' genes, given the potential for certain environments to yield increased positive function in the same domain as potential dysfunction, has implications for psychiatric nosology as well as a more dynamic understanding of the relationship between genes and culture. In addition to validating neuropsychiatric spectrum disorder nosologies by calling for similar methodological shifts in gene-environment-interaction studies, Brüne's position elevates the importance of environmental contexts - inclusive of socio-cultural variables - as mechanisms that contribute to clinical presentation. We assert that when models of susceptibility to plasticity and neuropsychiatric spectrum disorders are concomitantly considered, a new line of inquiry emerges into the co-evolution and co-determination of socio-cultural contexts and endophenotypes. This presents potentially unique opportunities, benefits, challenges, and responsibilities for research and practice in psychiatry

    Developmental mediation of genetic variation in response to the Fast Track Prevention Program

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    We conducted a developmental analysis of genetic moderation of the effect of the Fast Track intervention on adult externalizing psychopathology. The Fast Track intervention enrolled 891 children at high risk to develop externalizing behavior problems when they were in kindergarten. Half of the enrolled children were randomly assigned to receive 10 years of treatment, with a range of services and resources provided to the children and their families, and the other half to usual care (controls). We previously showed that the effect of the Fast Track intervention on participants\u27 risk of externalizing psychopathology at age 25 years was moderated by a variant in the glucocorticoid receptor gene. Children who carried copies of the A allele of the single nucleotide polymorphism rs10482672 had the highest risk of externalizing psychopathology if they were in the control arm of the trial and the lowest risk of externalizing psychopathology if they were in the treatment arm. In this study, we test a developmental hypothesis about the origins of this for better and for worse Gene × Intervention interaction (G × I): that the observed G × I effect on adult psychopathology is mediated by the proximal impact of intervention on childhood externalizing problems and adolescent substance use and delinquency. We analyzed longitudinal data tracking the 270 European American children in the Fast Track randomized control trial with available genetic information (129 intervention children, 141 control group peers, 69% male) from kindergarten through age 25 years. Results show that the same pattern of for better and for worse susceptibility to intervention observed at the age 25 follow-up was evident already during childhood. At the elementary school follow-ups and at the middle/high school follow-ups, rs10482672 predicted better adjustment among children receiving the Fast Track intervention and worse adjustment among children in the control condition. In turn, these proximal G × I effects early in development mediated the ultimate G × I effect on externalizing psychopathology at age 25 years. We discuss the contribution of these findings to the growing literature on genetic susceptibility to environmental intervention

    Developmental mediation of genetic variation in response to the Fast Track Prevention Program

    Get PDF
    We conducted a developmental analysis of genetic moderation of the effect of the Fast Track intervention on adult externalizing psychopathology. The Fast Track intervention enrolled 891 children at high risk to develop externalizing behavior problems when they were in kindergarten. Half of the enrolled children were randomly assigned to receive 10 years of treatment, with a range of services and resources provided to the children and their families, and the other half to usual care (controls). We previously showed that the effect of the Fast Track intervention on participants\u27 risk of externalizing psychopathology at age 25 years was moderated by a variant in the glucocorticoid receptor gene. Children who carried copies of the A allele of the single nucleotide polymorphism rs10482672 had the highest risk of externalizing psychopathology if they were in the control arm of the trial and the lowest risk of externalizing psychopathology if they were in the treatment arm. In this study, we test a developmental hypothesis about the origins of this for better and for worse Gene × Intervention interaction (G × I): that the observed G × I effect on adult psychopathology is mediated by the proximal impact of intervention on childhood externalizing problems and adolescent substance use and delinquency. We analyzed longitudinal data tracking the 270 European American children in the Fast Track randomized control trial with available genetic information (129 intervention children, 141 control group peers, 69% male) from kindergarten through age 25 years. Results show that the same pattern of for better and for worse susceptibility to intervention observed at the age 25 follow-up was evident already during childhood. At the elementary school follow-ups and at the middle/high school follow-ups, rs10482672 predicted better adjustment among children receiving the Fast Track intervention and worse adjustment among children in the control condition. In turn, these proximal G × I effects early in development mediated the ultimate G × I effect on externalizing psychopathology at age 25 years. We discuss the contribution of these findings to the growing literature on genetic susceptibility to environmental intervention
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