1,286 research outputs found
A proposed concept for a crustal dynamics information management network
The findings of a requirements and feasibility analysis of the present and potential producers, users, and repositories of space-derived geodetic information are summarized. A proposed concept is presented for a crustal dynamics information management network that would apply state of the art concepts of information management technology to meet the expanding needs of the producers, users, and archivists of this geodetic information
Velocity and processivity of helicase unwinding of double-stranded nucleic acids
Helicases are molecular motors which unwind double-stranded nucleic acids
(dsNA) in cells. Many helicases move with directional bias on single-stranded
(ss) nucleic acids, and couple their directional translocation to strand
separation. A model of the coupling between translocation and unwinding uses an
interaction potential to represent passive and active helicase mechanisms. A
passive helicase must wait for thermal fluctuations to open dsNA base pairs
before it can advance and inhibit NA closing. An active helicase directly
destabilizes dsNA base pairs, accelerating the opening rate. Here we extend
this model to include helicase unbinding from the nucleic-acid strand. The
helicase processivity depends on the form of the interaction potential. A
passive helicase has a mean attachment time which does not change between ss
translocation and ds unwinding, while an active helicase in general shows a
decrease in attachment time during unwinding relative to ss translocation. In
addition, we describe how helicase unwinding velocity and processivity vary if
the base-pair binding free energy is changed.Comment: To appear in special issue on molecular motors, Journal of Physics -
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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
Upgrade of the Glasgow photon tagging spectrometer for Mainz MAMI-C
The Glasgow photon tagging spectrometer at Mainz has been upgraded so that it
can be used with the 1500 MeV electron beam now available from the Mainz
microtron MAMI-C. The changes made and the resulting properties of the
spectrometer are discussed.Comment: 20 pages, 12 figure
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Vitamin D-responsive SGPP2 variants associated with lung cell expression and lung function
Background: Vitamin D is associated with lung health in epidemiologic studies, but mechanisms mediating observed associations are poorly understood. This study explores mechanisms for an effect of vitamin D in lung through an in vivo gene expression study, an expression quantitative trait loci (eQTL) analysis in lung tissue, and a population-based cohort study of sequence variants. Methods: Microarray analysis investigated the association of gene expression in small airway epithelial cells with serum 25(OH)D in adult non-smokers. Sequence variants in candidate genes identified by the microarray were investigated in a lung tissue eQTL database, and also in relation to cross-sectional pulmonary function in the Health, Aging, and Body Composition (Health ABC) study, stratified by race, with replication in the Framingham Heart Study (FHS). Results: 13 candidate genes had significant differences in expression by serum 25(OH)D (nominal p < 0.05), and a genome-wide significant eQTL association was detected for SGPP2. In Health ABC, SGPP2 SNPs were associated with FEV1 in both European- and African-Americans, and the gene-level association was replicated in European-American FHS participants. SNPs in 5 additional candidate genes (DAPK1, FSTL1, KAL1, KCNS3, and RSAD2) were associated with FEV1 in Health ABC participants. Conclusions: SGPP2, a sphingosine-1-phosphate phosphatase, is a novel vitamin D-responsive gene associated with lung function. The identified associations will need to be followed up in further studies
A cross-sectional study on the deprivation and sex differences in health-related fitness measures in school children
This study aimed to investigate deprivation and sex differences in selected health-relatedfitness measures in 9-12-year-old children. Data were captured on 3,407 children (49.3% boys; aged 10.5 ± 0.6 years). Cardiorespiratory fitness(20 m multistage shuttle run test; 20 m MSRT), muscular strength (handgrip strength) and body mass index (BMI) were measured. Welsh Index of Multiple Deprivation (WIMD) scores were used to make quintile groups. A two-way Analysis of Variance examined differences in BMI z-score by sex and WIMD quintiles. Two-wayAnalysis of Covariances investigated the effect of sex and WIMD quintiles on grip strength and shuttles achieved in 20 m MSRT, adjusting for BMI z-score and maturation, repectively. Independent of sex, children in the middle quintile had a significantly higher mean BMI z-score (p = 0.029) than their least deprived counterparts. There was a significant increase in grip strength (p = 0.005) and20 m MSRT (boys p < 0.001; girls p = 0.028) between most and least deprived quintiles. Significant differences in 20 m MSRT score were more apparent with decreases in deprivation in boys.Overall, inequalities exist in health-related fitness by sex and deprivation. These results can be used to inform focused services to improve current and future health
The impact of cash transfers to poor women in Colombia on BMI and obesity: Prospective cohort study
INTRODUCTION: Prevalence of obesity is rising in Latin America, is increasingly affecting socially disadvantaged groups, particularly women. Conditional cash transfers are recently established welfare interventions in the region. One, Familias en Accion, transfers ~20% of average monthly income to women in Colombia’s poorest families. Previous work has found that families buy more food as a result. We tested the hypothesis that participation in Familias would be associated with increasing body mass index (BMI) in participating women METHODS: Women from participating areas and control areas (matched on environmental and socioeconomic criteria) were surveyed in 2002 and 2006. Pregnant, breast-feeding or women aged<18 or with BMI<18.5kg/m(2) were excluded. The sample comprises 835 women from control and 1238 from treatment areas. Because some treatment areas started Familias shortly before baseline data collection, a dummy variable was created that identified exposure independent of time-point or area. Follow-up was 61.5%. BMI was measured by trained personnel using standardized techniques. Overweight was defined as BMI>25kg/m(2) and obesity as >30kg/m(2). The effect of Familias was estimated using linear regression (or logistic regression for dichotomous outcomes) in a double-difference technique, controlling for several individual, household and area characteristics, including parity and baseline BMI, using robust standard-errors clustered at area-level in an intention-to-treat analysis. RESULTS: At baseline, women’s mean age was 33.3 years and mean BMI 25.3kg/m(2); 12.3% women were obese. After adjustment, exposure to Familias was significantly associated with increased BMI (β=0.25, 95% CI 0.03, 0.47; p=0.03). Age (β=0.09; 95%CI 0.06, 0.13; p<0.001) and household wealth (β=0.78; 95%CI 0.41, 1.15; p<0.001) were also positively associated with BMI. Familias was also associated with increased odds of obesity (O.R.=1.27 95%CI 1.03, 1.57; p=0.03), as was age (O.R.=1.04; 95%CI 1.02, 1.06; p=0.001). CONCLUSION: Conditional cash transfers to poor women in Colombia are independently associated with increasing BMI and obesity risk. Although conditional cash transfers are generally regarded as popular and successful schemes, parallel interventions at individual, household and community level are needed to avoid unanticipated adverse outcomes
Maternal nutritional status, food intake and pregnancy weight gain in Nepal
This is the author's accepted version (version 2) of an article published by SAGE in Journal of Health Management, March 2016. The published version is available at http://pss.sagepub.com/lookup/doi/10.1177/0972063415625537Poor maternal nutrition during pregnancy may predispose to intrauterine growth restriction (IUGR), immunological and metabolic adaptations which manifest as low birth weight and increase the risk of adult non-communicable disease. This study examined the relationships between maternal nutritional status, food intake and pregnancy weight gain (PWG) which may account for risk of low birth weight (LBW) in Nepal
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