Analysis for perfluorocarboxylic acids/anions in surface waters and precipitation using GC--MS and analysis of PFOA from large-volume samples

The presence of perfluorocarboxylates (PFCAs) in the environment is of increasing concern, following the discovery of perfluoroalkyl acids (PFAs) in wildlife and human samples. Here we report a method forthe determination of (C2-C9) PFCAs by preparing the 2,4-difluoroanilides of the acids and analyzing by using GC-MS. Detector response was linear over the range 0.1 -1000 pg of each perfluoroalkyl anilide. A complete suite of PFCAs can be analyzed in an individual sample with the PFCAs detected at levels similar to or lower than those determined by other methods. For a comparison between the present method and the more common LC-MS/MS method, 10 replicates of a sewage treatment plant discharge were analyzed for perfluoro-octanoic acid (PFOA) using both methods. Results were nearly identical with low standard deviation (GC-MS 30.9 +/- 1.88 ng/L; while the LC-MS/MS 34.7 +/- 3.05 ng/L). PFCA concentrations for water samples collected from depth profiles in mid-Lake Ontario were analyzed by GC-MS with most PFCAs (C2-C8) present above the detection limit (0.5 ng/L). Major PFCAs were trifluoroacetate (TFA) (100 ng/L) and perfluorobutanoate (PFBA) (> 5 ng/L). Results for PFOA (2.5 ng/L) were in good agreement with recent analyses by LC-MS/MS. PFCAs were also detected in the precipitation samples at concentrations lower than those of the samples from the lake profiles or sewage treatment plants (STPs) effluent. Since PFOA levels may be less than the lower detection limit (<0.5 ng/L) in 1 L samples, a method for large volumes using XAD-7 resin was developed that allows detection to 0.01 ng/L. This method was applied to Lake Superior samples which produced good agreement for C6-C9 PFCAs between regular analysis (GC-MS) and the XAD-7 followed by GC-MS analysis.     

Econutrition: implementation models from the Millennium Villages Project in Africa

Econutrition integrates environmental health and human health, with a particular focus on the interactions among the fields of agriculture, ecology, and human nutrition. Soil loss and degradation and human undernutrition are major barriers to economic development in Africa. A primary aim of the Millennium Villages Project in Africa is to meet the Millennium Development Goals by integrated multisectoral interventions in health and nutrition, agriculture, and environmental sustainability in hunger and poverty hot spots in Africa. Econutrition is only one example of how interdisciplinary approaches are not only critical to alleviating extreme poverty but also fundamental to linking basic science understanding in multiple areas. Human health and agricultural productivity gain, and the costs of the gains are lowered, when we take the opportunity to apply different disciplines through cross-sectoral, thematically linked interventions.     

Comparison of the effect of 360° versus two-dimensional virtual reality video on history taking and physical examination skills learning among undergraduate medical students: a randomized controlled trial

Virtual Reality - Before caring for patients, video instruction is commonly used for undergraduate medical students, and 360° virtual reality (VR) videos have gained increasing interest in...     

Modeling residential indoor concentrations of PM2.5, NO2, NOx,and secondhand smoke in the Subpopulations and Intermediate Outcome Measures in COPD (SPIROMICS) Air study

Increased outdoor concentrations of fine particulate matter (PM_2.5) and oxides of nitrogen (NO₂, NO_x) are associated with respiratory and cardiovascular morbidity in adults and children. However, people spend most of their time indoors and this is particularly true for individuals with chronic obstructive pulmonary disease (COPD). Both outdoor and indoor air pollution may accelerate lung function loss in individuals with COPD, but it is not feasible to measure indoor pollutant concentrations in all participants in large cohort studies. We aimed to understand indoor exposures in a cohort of adults (SPIROMICS Air, the SubPopulations and Intermediate Outcome Measures in COPD Study of Air pollution). We developed models for the entire cohort based on monitoring in a subset of homes, to predict mean 2-week–measured concentrations of PM_2.5, NO₂, NO_x, and nicotine, using home and behavioral questionnaire responses available in the full cohort. Models incorporating socioeconomic, meteorological, behavioral, and residential information together explained about 60% of the variation in indoor concentration of each pollutant. Cross-validated R² for best indoor prediction models ranged from 0.43 (NO_x) to 0.51 (NO₂). Models based on questionnaire responses and estimated outdoor concentrations successfully explained most variation in indoor PM_2.5, NO₂, NO_x, and nicotine concentrations.     

Aging and emotional memory: Cognitive mechanisms underlying the positivity effect.

Younger adults tend to remember negative information better than positive or neutral information (negativity bias). The negativity bias is reduced in aging, with older adults occasionally exhibiting superior memory for positive, as opposed to negative or neutral, information (positivity bias). Two experiments with younger (N = 24 in Experiment 1, N = 25 in Experiment 2; age range: 18?35 years) and older adults (N = 24 in both experiments; age range: 60?85 years) investigated the cognitive mechanisms responsible for age-related differences in recognition memory for emotional information. Results from diffusion model analyses (R. Ratcliff, 1978) indicated that the effects of valence on response bias were similar in both age groups but that Age × Valence interactions emerged in memory retrieval. Specifically, older adults experienced greater overall familiarity for positive items than younger adults. We interpret this finding in terms of an age-related increase in the accessibility of positive information in long-term memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Relation Between Brain Activity During Memory Tasks and Years of Education in Young and Older Adults.

Higher education is associated with less age-related decline in cognitive function, but the mechanism of this protective effect is unknown. The authors examined the effect of age on the relation between education and brain activity by correlating years of education with activity measured using functional MRI during memory tasks in young and older adults. In young adults, education was negatively correlated with frontal activity, whereas in older adults, education was positively correlated with frontal activity. Medial temporal activity was associated with more education in young adults but less education in older adults. This suggests that the frontal cortex is engaged by older adults, particularly by the highly educated, as an alternative network that may be engaged to aid cognitive function. (PsycINFO Database Record (c) 2010 APA, all rights reserved)