653 research outputs found
Multidisciplinary approaches to address food insecurity and nutrition among youth and their families
Our aim in publishing this issue of JARC on nutrition and food insecurity is to understand the factors associated with nutrition and food insecurity in the U.S. and around the world; to elucidate the potential consequences of food insecurity on physical and mental health; and to raise awareness and identify solutions to address this complex issue. We also aim to encourage collaboration across disciplines in order to frame initiatives that reduce these threats to child health, well-being and success
Socioeconomic and Cultural County-level Factors Associated with Race/Ethnic Differences in Body Mass Index in 4th Grade Students in Texas
Purpose: To evaluate the relationship between county-level socioeconomic environment and the propensity to be overweight or obese by race/ethnic group in a sample of fourth grade children the Texas public school system.
Methods: The data used come from the School Physical Activity and Nutrition (SPAN) surveillance study – a surveillance study of school-aged children in Texas. The outcome variable used was Body Mass Index (BMI) categorized as underweight/normal/healthy, overweight, and obese. Exposure variables were derived from county-level Hispanic and Black concentration and socioeconomic data using the Human Security Index (HSI) as a framework. We made comparisons between Non-Hispanic White, Black and Hispanic children enrolled in the fourth grade. We used bivariate and regression analysis using jackknife variance estimates.
Results: Hispanic and Black children were more likely to be obese and overweight than non-Hispanic White children. Hispanic and Black children were more likely to live in counties with higher economic, educational and social stress than non-Hispanic White children. In the logistic regression analysis comparing the odds of overweight or obese to underweight/healthy/normal weight, both Hispanic and Black children continued to have a higher odds of overweight and obesity than non-Hispanic White children. In separate regression analyses for each race/ethnic group (ie, Hispanic, Black, and White students) the county-level educational and social stress variables had a significant association with overweight and obesity in Hispanic children only. Hispanic ethnic concentration was associated with the odds of being overweight but not obese, while percent Black was associated with obesity in Hispanic children. There were no significant associations between socioeconomic or ethnic concentration and overweight or obese in Black children.
Discussion: The results from this study indicate that county-level effects on childhood obesity may be more than just socioeconomics and ethnic concentration. Future research should involve multiple levels of analysis, including census tract, school and home variables simultaneously, in order to understand how the environments children live in impact their risk for obesity and how these influences may vary by race/ethnicity
Tensile strained membranes for cavity optomechanics
We investigate the optomechanical properties of tensile-strained ternary
InGaP nanomembranes grown on GaAs. This material system combines the benefits
of highly strained membranes based on stoichiometric silicon nitride, with the
unique properties of thin-film semiconductor single crystals, as previously
demonstrated with suspended GaAs. Here we employ lattice mismatch in epitaxial
growth to impart an intrinsic tensile strain to a monocrystalline thin film
(approximately 30 nm thick). These structures exhibit mechanical quality
factors of 2*10^6 or beyond at room temperature and 17 K for eigenfrequencies
up to 1 MHz, yielding Q*f products of 2*10^12 Hz for a tensile stress of ~170
MPa. Incorporating such membranes in a high finesse Fabry-Perot cavity, we
extract an upper limit to the total optical loss (including both absorption and
scatter) of 40 ppm at 1064 nm and room temperature. Further reductions of the
In content of this alloy will enable tensile stress levels of 1 GPa, with the
potential for a significant increase in the Q*f product, assuming no
deterioration in the mechanical loss at this composition and strain level. This
materials system is a promising candidate for the integration of strained
semiconductor membrane structures with low-loss semiconductor mirrors and for
realizing stacks of membranes for enhanced optomechanical coupling.Comment: 10 pages, 3 figure
Low specificity of determine HIV1/2 RDT using whole blood in south west Tanzania
Objective: To evaluate the diagnostic performance of two rapid detection tests (RDTs) for HIV 1/2 in plasma and in whole blood samples.
Methods:
More than 15,000 study subjects above the age of two years participated in two rounds of a cohort study to determine the prevalence of HIV. HIV testing was performed using the Determine HIV 1/2 test (Abbott) in the first (2006/2007) and the HIV 1/2 STAT-PAK Dipstick Assay (Chembio) in the second round (2007/2008) of the survey. Positive results were classified into faint and strong bands depending on the visual appearance of the test strip and confirmed by ELISA and Western blot.
Results:
The sensitivity and specificity of the Determine RDT were 100% (95% confidence interval = 86.8 to 100%) and 96.8% (95.9 to 97.6%) in whole blood and 100% (99.7 to 100%) and 97.9% (97.6 to 98.1%) in plasma respectively. Specificity was highly dependent on the tested sample type: when using whole blood, 67.1% of positive results were false positive, as opposed to 17.4% in plasma. Test strips with only faint positive bands were more often false positive than strips showing strong bands and were more common in whole blood than in plasma. Evaluation of the STAT-PAK RDT in plasma during the second year resulted in a sensitivity of 99.7% (99.1 to 99.9%) and a specificity of 99.3% (99.1 to 99.4%) with 6.9% of the positive results being false.
Conclusions:
Our study shows that the Determine HIV 1/2 strip test with its high sensitivity is an excellent tool to screen for HIV infection, but that – at least in our setting – it can not be recommended as a confirmatory test in VCT campaigns where whole blood is used
High prevalence of ST-elevation, early repolarization, and left ventricular hypertrophy during the eligibility assessment for an HIV vaccine trial in young, healthy Tanzanians
BACKGROUND:
Vaccinia based immunizations have caused myo/pericarditis and vaccine study volunteers are monitored by ECG. We report ECG outcome obtained during the screening period for an HIV vaccine trial.
METHODS:
ECG was performed in healthy Tanzanian volunteers. ECG abnormalities and findings interfering with the interpretation of myo/pericarditis were subject to study ineligibility. We determined the prevalence of left ventricular hypertrophy (LVH) defined by the Sokolow-Lyon (SL) or the Cornell index, ST-elevations and early repolarization (ERP) in association with gender, age, BMI and body height by regression analysis adjusted for gender and age.
RESULTS:
In 257 volunteers (median age 23 years, 63% males) overall positivity for LVH defined by SL or Cornell criteria was seen in 20.6% and 3.5%, ST-elevations ≥ 0.1 mV or ≥ 0.2 mV in 77.8% and 38.1%, and ERP in 23.4%. Positive SL criteria were associated with male gender (PR 7.84, p < 0.001) and lower age (PR 0.70, p = 0.002), and associated with increased body height and lower BMI in univariate analysis. Positive Cornell criteria were only associated with lower age (PR 0.44, p = 0.010). ST-elevations ≥ 0.2 mV were associated with male gender (PR 8.05, p < 0.001) and lower age (PR 0.81, p = 0.003), and ERP with male gender (PR 2.86, p < 0.001). Vaccine study ineligibility due to ECG findings was concluded in 22.1% of the screening population.
CONCLUSIONS:
High prevalence of LVH according to SL in association with ST-elevation and ERP is especially found in young and male Africans. ECG variations need to be considered for eligibility criteria in studies investigating potential cardiotoxic agents in Africa
Preferential Targeting of Conserved Gag Regions after Vaccination with a Heterologous DNA prime - Modified Vaccinia Ankara (MVA) boost HIV-1 vaccine regimen
Prime-boost vaccination strategies against HIV-1 often include multiple variants for a given immunogen for better coverage of the extensive viral diversity. To study the immunologic effects of this approach, we characterized breadth, phenotype, function and specificity of Gag-specific T cells induced by a DNA-prime Modified Vaccinia Ankara (MVA)-boost vaccination strategy, which uses mismatched Gag immunogens in the TamoVac 01 phase IIa trial. Healthy Tanzanian volunteers received three injections of the DNA-SMI vaccine encoding for a subtype B and AB-recombinant Gagp37 and two vaccinations with MVA-CMDR encoding subtype A Gagp55 Gag-specific T-cell responses were studied in 42 vaccinees using fresh peripheral blood mononuclear cells. After the first MVA-CMDR boost, vaccine-induced IFN-γ(+) Gag-specific T cell responses were dominated by CD4(+) T cells (compared to CD8(+) T cells, p<0.001) that co-expressed IL-2 (66.4%) and/or TNFα (63.7%). A median of 3 antigenic regions were targeted with a higher median response magnitude to Gagp24 regions - more conserved between prime and boost - as compared to regions within Gagp15 (not primed) and Gagp17 (less conserved, both p<0.0001). Four regions within Gagp24 were each targeted by 45% to 74% of vaccinees upon restimulation with DNA-SMI-Gag matched peptides. The response rate to individual antigenic regions correlated with the sequence homology between the MVA and DNA Gag encoded immunogens (p=0.04, r(2)=0.47). In summary, after the first MVA-CMDR boost, the sequence-mismatched DNA-prime MVA-boost vaccine strategy induced a Gag-specific T cell response that was dominated by polyfunctional CD4(+) T cells and that targeted multiple antigenic regions within the conserved Gagp24 Protein.IMPORTANCE Genetic diversity is a major challenge for the design of vaccines against variable viruses. While including multiple variants for a given immunogen in prime-boost vaccination strategies is one approach that aims to improve coverage for global virus variants, the immunologic consequences of this strategy have been poorly defined so far. It is unclear whether inclusion of multiple variants in prime-boost vaccination strategies improves recognition of variant viruses by T cells and by which mechanisms this would be achieved; either by improved cross-recogniton of multiple variants for a given antigenic region or rather through preferential targeting of antigenic regions more conserved between prime and boost. Engineering vaccines to induce adaptive immune responses that preferentially target conserved antigenic regions of viral vulnerability might facilitate better immune control after preventive and therapeutic vaccination for HIV and for other variable viruses
Research contributions on childhood obesity from a public-private partnership
BACKGROUND: Childhood obesity remains a significant global problem with immediate and long-term individual health and societal consequences. Targets for change should include the most potent and predictive factors for obesity at all levels of the personal, social and physical environments. The Michael & Susan Dell Center for Healthy Living (‘the Center’) is a public-private partnership that was developed to address child health issues through research, service, and education. This overview paper introduces a special issue of seven articles on childhood obesity from the Center, and the implications of this research for obesity prevention. METHODS AND RESULTS: A review of the literature on public-private partnerships was undertaken and key components of the partnership between the Michael & Susan Dell Foundation and the Center were compared for compatibility. The conceptual framework for Center research, based on social cognitive theory and the social-ecological model, is explained. An overview of papers in this special issue, relative to the conceptual framework, and the implications of this research for childhood obesity prevention, are provided. CONCLUSIONS: The public-private partnership that created the Michael & Susan Dell Center for Healthy Living has been instrumental in motivating the Center’s academic faculty to focus their research on improvements in child, family and community health through etiologic, epidemiologic, methodologic and intervention research. This special issue extends this work and places particular emphasis on socioeconomic inequalities in addressing the obesity problem in the U.S. and worldwide
Salinity and Livestock Water Quality
Experiments with albino rates were undertaken preliminary to work with large animals. The purpose here was two-fold: (1) to compare several kinds of salts and get some idea of their relative toxicities; and (2) to establish what concentrations of salts would be best used in experimental work with large animals
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