N-15 NMR Spectroscopy as a Method for Comparing the Rates of Imidization of Several Diamines

The relative rates of the conversion of amide-acid to imide was measured for a series or aromatic diamines that have been identified as potential replacements for 4,4'-methylene dianiline (MDA) in high-temperature polyimides and polymer composites. These rates were compared with the N-15 NMR resonances of the unreacted amines. The initial rates of imidization track with the difference in chemical shift between the amine nitrogens in MDA and those in the subject diamines. This comparison demonstrated that N-15 NMR spectroscopy is appropriate for the rapid screening of candidate diamines to determine their reactivity relative to MDA, and can serve to provide guidance to the process of creating the time-temperature profiles used in processing these materials into polymer matrix composites

Voluntary Wheel Running Augments Vascular Function in Rats with Chronic Kidney Disease

Please view abstract in the attached PDF file

Diurnal cortisol and obesity in adolescents with and without Down syndrome

BackgroundThe prevalence of obesity in adolescents with Down syndrome (DS) far exceeds that in the general population. Cortisol, an adrenal hormone, can be obesogenic when dysregulated. However, the diurnal patterns of this hormone have not been examined among individuals with DS. Variations in adiposity may also mediate cortisol regulation. This study sought to examine diurnal cortisol patterns in adolescents with DS as well as associations between cortisol function and obesity.MethodA total of 32 adolescents, including 16 with DS and 16 controls with typical development (TD) of similar sex, age and Tanner pubertal stage (P > 0.05), participated in this preliminary study. Participants completed a dual‐energy X‐ray absorptiometry scan to measure body composition and collected saliva samples for cortisol measurements in the morning, afternoon and night. Linear mixed models with random intercepts and repeated measures were used to examine the daily trajectory of log‐transformed cortisol concentrations between adolescents with and without DS. A second model examined the interaction between DS and presence of elevated body fatness.ResultsAdolescents with DS had higher morning cortisol concentrations (intercept = 0.37 μg/dL), but this was not significantly different than in TD (0.35 μg/dL, P = 0.16). Cortisol significantly declined across hours (b = −0.026 μg/dL/h, P  0.05; d = 0.30).ConclusionsThis study is the first to examine diurnal cortisol in DS but is limited in sample size. These preliminary findings suggest that diurnal cortisol patterns are not significantly different between adolescents with DS and TD and that cortisol levels are not associated with adiposity in this population. Despite these non‐significant differences, youth with DS continue to be an ‘at‐risk’ population for paediatric obesity in need of clinical intervention.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151976/1/jir12682_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151976/2/jir12682.pd

Improved Thermal Design of a Compression Mold

An analysis of the heat transfer in a tool for producing neat resin disks was conducted to determine how to bring about a better agreement between the tool temperature and the applied temperature profile. Using the commercial code FLUENT to investigate the relative effects of heat conduction into the tool and heat loss from the tool by convection, it was shown that convective heat transfer appears more important than conduction in controlling the tool performance. Decreasing the height of the tool was predicted to decrease the heat losses by convection. Redesign of the tool based on this analysis resulted in the tool experiencing the applied temperature profile

Home and neighbourhood correlates of BMI among children living in socioeconomically disadvantaged neighbourhoods

A detailed understanding of the underlying drivers of obesity-risk behaviours is needed to inform prevention initiatives, particularly for individuals of low socioeconomic position who are at increased risk of unhealthy weight gain. However, few studies have concurrently considered factors in the home and local neighbourhood environments, and little research has examined determinants among children from low socioeconomic backgrounds. The present study examined home, social and neighbourhood correlates of BMI (kg/m2) in children living in disadvantaged neighbourhoods. Cross-sectional data were collected from 491 women with children aged 5–12 years living in forty urban and forty rural socioeconomically disadvantaged areas (suburbs) of Victoria, Australia in 2007 and 2008. Mothers completed questionnaires about the home environment (maternal efficacy, perceived importance/beliefs, rewards, rules and access to equipment), social norms and perceived neighbourhood environment in relation to physical activity, healthy eating and sedentary behaviour. Children\u27s height and weight were measured at school or home. Linear regression analyses controlled for child sex and age. In multivariable analyses, children whose mothers had higher efficacy for them doing physical activity tended to have lower BMI z scores (B = − 0·04, 95 % CI − 0·06, − 0·02), and children who had a television (TV) in their bedroom (B = 0·24, 95 % CI 0·04, 0·44) and whose mothers made greater use of food as a reward for good behaviour (B = 0·05, 95 % CI 0·01, 0·09) tended to have higher BMI z scores. Increasing efficacy among mothers to promote physical activity, limiting use of food as a reward and not placing TV in children\u27s bedrooms may be important targets for future obesity prevention initiatives in disadvantaged communities

Body Composition Measurements from Birth through 5 Years: Challenges, Gaps, and Existing & Emerging Technologies—A National Institutes of Health workshop

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156150/2/obr13033_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156150/1/obr13033.pd

Prenatal Organochlorine Compound Exposure, Rapid Weight Gain, and Overweight in Infancy

Background: Although it has been hypothesized that fetal exposure to endocrine-disrupting chemicals may increase obesity risk, empirical data are limited, and it is uncertain how early in life any effects may begin. Objectives: We explored whether prenatal exposure to several organochlorine compounds (OCs) is associated with rapid growth in the first 6 months of life and body mass index (BMI) later in infancy. Methods: Data come from the INMA (Infancia y Medio-Ambiente) Child and Environment birth cohort in Spain, which recruited 657 women in early pregnancy. Rapid growth during the first 6 months was defined as a change in weight-for-age z-scores > 0.67, and elevated BMI at 14 months, as a z-score ≥ the 85th percentile. Generalized linear models were used to estimate the risk of rapid growth or elevated BMI associated with 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene (DDE), hexachlorobenzene, β-hexachlorohexane, and polychlorinated biphenyls in first-trimester maternal serum. Results: After multivariable adjustment including other OCs, DDE exposure above the first quartile was associated with doubling of the risk of rapid growth among children of normal-weight (BMI < 25 kg/m2), but not overweight, mothers. DDE was also associated with elevated BMI at 14 months (relative risk per unit increase in log DDE = 1.50; 95% confidence interval, 1.11–2.03). Other OCs were not associated with rapid growth or elevated BMI after adjustment. Conclusions: In this study we found prenatal DDE exposure to be associated with rapid weight gain in the first 6 months and elevated BMI later in infancy, among infants of normal-weight mothers. More research exploring the potential role of chemical exposures in early-onset obesity is needed.This work was supported by grants from the Spanish Ministry of Health (FIS-PI041436), Instituto de Salud Carlos III (Red INMA G03/176 and CB06/02/0041), the Generalitat de Catalunya-CIRIT (Consejo Interdepartamental de Investigación e Innovación Tecnológica) (1999SGR 00241), and the Fundació Roger Torne