Racial/ethnic differences in dietary intake among a diverse sample of adolescents: An experimental study.

BACKGROUND: African-American (AA) and Hispanic/Latina (HL) females have higher obesity prevalence than do non-Hispanic Whites (NHW); this may be due to AA and HL consuming more energy-dense foods in response to stressors. OBJECTIVES: This study examined racial/ethnic differences in dietary intake under controlled conditions (relaxation and stress) in a diverse sample of adolescent females. METHODS: Participants included 120 adolescent females (30% AA, 37% HL and 33% NHW) who participated in a laboratory food intake study. Using a randomized cross-over design, ad libitum food consumption was measured following control/relaxation and social-evaluative stress conditions. Food intake was indexed as consumed calories, added sugars and solid fats. RESULTS: The effect of laboratory conditions on food intake varied by race/ethnicity, such that AA consumed more energy following relaxation than following stress. For NHW and HL, food intake did not differ between conditions. CONCLUSIONS: To the best of our knowledge, these findings are the first to directly observe racial/ethnic differences in food intake in response to acute stress, which may contribute to obesity-related health disparities.

The Influence of Extreme Heat on Police and Fire Department Services in 23 U.S. Cities.

Recent research suggests that extreme heat affects the demand for emergency services, including police and fire department incidents. Yet there is limited understanding of impacts across U.S. cities, with varying population sizes, and between different climates. This study sought to examine the daily utilization of police and fire department services, during hot days in 23 U.S. cities representing six climate zones using relative risk (RR) and time series analyses of daily police and fire department incidents. The warm season analyses utilized three temperature metrics: daily maximum temperature (TMAX), daily maximum heat index (HIMAX), and the preceding daily minimum temperature (TMIN). Across these cities, the RR of police department incidents on days where TMAX was at or above the 95th percentile significantly increased within a range from 3% (95% confidence interval [CI]: 0.3%, 6.3%) to 57% (95% CI: 24.5%, 89.7%), compared with a nonhot day. At the same temperature thresholds, the RR of fire department dispatches increased from 6% (95% CI: 3.0%, 8.6%) to 18% (95% CI: 15.2%, 21.6%). These results remained consistent across temperature metrics and consecutive days of extreme heat. The estimated effects of daily maximum temperature, daily maximum heat index, and daily minimum temperature were nonlinear for police and fire department incidents across all cities. These findings inform climate change adaptation strategies, preparing budgets and personnel for emergency agencies to ensure resilience as periods of extreme heat increase in frequency, severity, and duration.

Role of Conserved Gly-Gly Pairs on the Periplasmic Side of LacY.

On the periplasmic side of LacY, two conserved Gly-Gly pairs in helices II and XI (Gly46 and Gly370, respectively) and helices V and VIII (Gly159 and Gly262, respectively) allow close packing of each helix pair in the outward (periplasmic)-closed conformation. Previous studies demonstrate that replacing one Gly residue in each Gly-Gly pair with Trp leads to opening of the periplasmic cavity with abrogation of transport activity, but an increased rate of galactoside binding. To further investigate the role of the Gly-Gly pairs, 11 double-replacement mutants were constructed for each pair at positions 46 (helix II) and 262 (helix VIII). Replacement with Ala or Ser results in decreased but significant transport activity, while replacements with Thr, Val, Leu, Asn, Gln, Tyr, Trp, Glu, or Lys exhibit very little or no transport. Remarkably, however, the double mutants bind galactoside with affinities 10-20-fold higher than that of the pseudo-WT or WT LacY. Moreover, site-directed alkylation of a periplasmic Cys replacement indicates that the periplasmic cavity becomes readily accessible in the double-replacement mutants. Molecular dynamics simulations with the WT and double-Leu mutant in the inward-open/outward-closed conformation provide support for this interpretation.