588 research outputs found
The Effects of Temperature, Humidity and Aircraft Fluid Exposure on T800H/3900-2 Composites Bonded with AF-555M Adhesive
Fiber reinforced resin matrix composites and structural adhesives have found increased usage on commercial and military aircraft in recent years. Due to the lack of service history of these relatively new material systems, their long-term aging performance has not been well established. In this study, single lap shear specimens (SLS) were fabricated by secondary bonding of Scotch-Weld(TradeMark) AF-555M between pre-cured adherends comprised of T800H/3900-2 uni-directional laminates. The adherends were co-cured with wet peel-ply for surface preparation. Each bond-line of the SLS specimen was measured to determine thickness and inspected visually using an optical microscope for voids. A three-year environmental aging plan for the SLS specimens at 82 C (180 F) and 85% relative humidity was initiated. SLS strengths were measured for both controls and aged specimens at room temperature and 82 C. The effect of this exposure on lap shear strength and failure modes to date is reported. In addition, the effects of water, saline water, deicing fluid, JP-5 jet fuel and hydraulic fluid on both the composite material and the adhesive bonds were investigated. The up to date results on the effects of these exposures will be discussed
Breast milk iodine and perchlorate concentrations in lactating Boston-area women
Context: Breastfed infants rely on adequate maternal dietary iodine intake. Objective: Our objective was to measure breast milk iodine and perchlorate, an inhibitor of iodide transport into the thyroid and potentially into breast milk, in Boston-area women. Participants: The study included 57 lactating healthy volunteers in the Boston area. Measurements: Breast milk iodine and perchlorate concentrations and urine iodine, perchlorate, and cotinine concentrations were measured. For comparison, iodine and perchlorate levels in infant formulae were also measured. Results: Median breast milk iodine content in 57 samples was 155 μg/liter (range, 2.7-1968 μg/liter). Median urine iodine was 114 μg/liter (range, 25-920 μg/liter). Perchlorate was detectable in all 49 breast milk samples (range, 1.3-411 μg/liter), all 56 urine samples (range, 0.37-127 μg/liter), and all 17 infant formula samples (range, 0.22-4.1 μg/liter) measured. Breast milk iodine content was significantly correlated with urinary iodine per gram creatinine and urinary cotinine but was not significantly correlated with breast milk or urinary perchlorate. Conclusions: Perchlorate exposure was not significantly correlated with breast milk iodine concentrations. Perchlorate was detectable in infant formula but at lower levels than in breast milk. Forty-seven percent of women sampled may have been providing breast milk with insufficient iodine to meet infants' requirements. Copyright © 2007 by The Endocrine Society
Shame, Trauma, Resiliency and Alcohol Related Behaviors in Puerto Rican Populations
Puerto Rico has endured horrendous natural disasters in the last few years, leaving thousands to cope with the aftermath; a mental health crisis. Therefore, understanding how Puerto Ricans navigate adversities, be that childhood adversity, natural disasters or daily stress is of utmost importance. Understanding the role resilience and drinking play in Puerto Rico will help us to further understand how they navigate adversities. Hence the reason why in this study we looked at how Adverse Childhood Experiences, Perceived Stress, Natural Disaster Adversity and Shame relate to each other and to Drinking behaviors and Resiliency. Data were collected on Puerto Rico via an online survey. Several individuals participated in the study (N = 189). Modifying variables included, age, place of residence on the island, gender, ethnicity, education, occupation and socio economic status. The results demonstrated significant differences between some modifying variables. Differences were seen between men and women in levels of Shame and ACES. No significant differences were found between ethnicities in levels of Shame, Stress, ACES, Hurricane Adversities and Resiliency. Similarly, no relationship was found between respondents level of drinking and SES. When looking at the sample as a whole there was no relationship between ACES and hurricane adversities as well as with drinking. However, there appears to be a positive relationship between ACES and Shame, and a small positive relationship between drinking and Shame. On the other hand, a negative relationship was found between Shame, ACES and Resiliency. However, a small positive relationship was found between the number of drinks people have and Resiliency. Additional analysis was conducted to further understand these variables and their relationships. Additional research, exploratory research, is needed to understand the variables and the relationship between them. Exploratory research is needed as a way to further understand the role culture plays in understanding Shame, ACES, Stress, Hurricane Adversities, Drinking and Resiliency in Puerto Rico
Urinary biomarkers of exposure to insecticides, herbicides, and one insect repellent among pregnant women in Puerto Rico
Abstract
Background
There are potential adverse health risks to the mother and fetus from exposure to pesticides. Thus, studies of exposure to pesticides among pregnant women are of interest as they will assist with understanding the potential burden of exposure globally, identifying sources of exposure, and designing epidemiology studies.
Methods
We measured urinary concentrations of the insect repellent N-N-diethyl-meta-toluamide (DEET) and two of its metabolites [3-diethyl-carbamoyl benzoic acid (DCBA) and N,N-diethyl-3-hydroxymethylbenzamide (DHMB)], four pyrethroid insecticide metabolites [4-fluoro-3-phenoxybenzoic acid (4-F-3-PBA); 3-phenoxybenzoic acid (3-PBA); trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (trans-DCCA); and cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane carboxylic acid (cis-DBCA)], and two chlorophenoxy herbicides [2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T)] in 54 pregnant women from Puerto Rico at three separate time points (20 ± 2 weeks, 24 ± 2 weeks, and 28 ± 2 weeks of gestation). We calculated the distributions of the biomarker concentrations and compared them to those of women of reproductive age from the general U.S. population where available, and estimated the within-subject temporal variability of these repeated measurements. We also collected questionnaire data on demographics, consumption of select fruits, vegetables, and legumes in the past 48-hr, and pest-related issues, and associations between these variables and biomarker concentrations were examined.
Results
We found that 95th percentile urinary concentrations of DEET, 3-PBA, trans-DCCA, and 2,4-D were lower than women of reproductive age on the U.S. mainland, whereas 95th percentile urinary concentrations of 4-F-3-PBA, cis-DBCA, and 2,4,5-T were similar. DCBA, the only urinary biomarker detected in >50% of the samples, showed fair to good reproducibility across pregnancy (intraclass correlation coefficient: 0.60). Women were more likely (p <0.05) to have greater urinary concentrations of pesticide biomarkers if they were less educated (DCBA and trans-DCCA), unemployed (DHMB), or married (2,4-D), had consumed collards or spinach in past 48-hr (2,4-D) or had been using insect repellent since becoming pregnant (DCBA), or were involved with residential applications of pesticides (trans-DCCA).
Conclusions
We identified concentrations and predictors of several pesticides among pregnant women in Puerto Rico. Further research is needed to understand what aspects of the predictors identified lead to greater exposure, and whether exposure during pregnancy is associated with adverse health.http://deepblue.lib.umich.edu/bitstream/2027.42/109451/1/12940_2014_Article_800.pd
HIV-positive parents, HIV-positive children, and HIV-negative children’s perspectives on disclosure of a parent’s and child’s illness in Kenya
HIV disclosure from parent to child is complex and challenging to HIV-positive parents and healthcare professionals. The purpose of the study was to understand the lived experiences of HIV-positive parents and their children during the disclosure process in Kenya. Sixteen HIV-positive parents, seven HIV-positive children, and five HIV-negative children completed semistructured, in-depth interviews. Data were analyzed using the Van Kaam method; NVivo 8 software was used to assist data analysis. We present data on the process of disclosure based on how participants recommended full disclosure be approached to HIV-positive and negative children. Participants recommended disclosure as a process starting at five years with full disclosure delivered at 10 years when the child was capable of understanding the illness, or by 14 years when the child was mature enough to receive the news if full disclosure had not been conducted earlier. Important considerations at the time of full disclosure included the parent’s and/or child’s health statuses, number of infected family members’ illnesses to be disclosed to the child, child’s maturity and understanding level, and the person best suited to deliver full disclosure to the child. The results also revealed it was important to address important life events such as taking a national school examination during disclosure planning and delivery. Recommendations are made for inclusion into HIV disclosure guidelines, manuals, and programs in resource-poor nations with high HIV prevalence
Association of prenatal perchlorate, thiocyanate, and nitrate exposure with neonatal size and gestational age
BACKGROUND: Perchlorate and similar anions compete with iodine for uptake into the thyroid by the sodium iodide symporter (NIS). This may restrict fetal growth via impaired thyroid hormone production. METHODS: We collected urine samples from 107 pregnant women and used linear regression to estimate differences in newborn size and gestational age associated with increases in perchlorate, thiocyanate, nitrate, and perchlorate equivalence concentrations (PEC; measure of total NIS inhibitor exposure). RESULTS: NIS inhibitor concentrations were not associated with newborn weight, length, or gestational age. Each 2.62ng/mug creatinine increase in perchlorate was associated with smaller head circumference (0.32cm; 95% CI: -0.66, 0.01), but each 3.38ng/mug increase in PEC was associated with larger head circumference (0.48cm; -0.01, 0.97). CONCLUSIONS: These anions may have effects on fetal development (e.g. neurocognitive) that are not reflected in gross measures. Future research should focus on other abnormalities in neonates exposed to NIS inhibitors
Urinary Perchlorate and Thyroid Hormone Levels in Adolescent and Adult Men and Women Living in the United States
BACKGROUND: Perchlorate is commonly found in the environment and known to inhibit thyroid function at high doses. Assessing the potential effect of low-level exposure to perchlorate on thyroid function is an area of ongoing research. OBJECTIVES: We evaluated the potential relationship between urinary levels of perchlorate and serum levels of thyroid stimulating hormone (TSH) and total thyroxine (T(4)) in 2,299 men and women, ≥ 12 years of age, participating in the National Health and Nutrition Examination Survey (NHANES) during 2001–2002. METHODS: We used multiple regression models of T(4) and TSH that included perchlorate and covariates known to be or likely to be associated with T(4) or TSH levels: age, race/ethnicity, body mass index, estrogen use, menopausal status, pregnancy status, premenarche status, serum C-reactive protein, serum albumin, serum cotinine, hours of fasting, urinary thiocyanate, urinary nitrate, and selected medication groups. RESULTS: Perchlorate was not a significant predictor of T(4) or TSH levels in men. For women overall, perchlorate was a significant predictor of both T(4) and TSH. For women with urinary iodine < 100 μg/L, perchlorate was a significant negative predictor of T(4) (p < 0.0001) and a positive predictor of TSH (p = 0.001). For women with urinary iodine ≥ 100 μg/L, perchlorate was a significant positive predictor of TSH (p = 0.025) but not T(4) (p = 0.550). CONCLUSIONS: These associations of perchlorate with T(4) and TSH are coherent in direction and independent of other variables known to affect thyroid function, but are present at perchlorate exposure levels that were unanticipated based on previous studies
Direct Measurement of Perchlorate Exposure Biomarkers in a Highly Exposed Population: A Pilot Study
Exposure to perchlorate is ubiquitous in the United States and has been found to
be widespread in food and drinking water. People living in the lower Colorado
River region may have perchlorate exposure because of perchlorate in ground
water and locally-grown produce. Relatively high doses of perchlorate can
inhibit iodine uptake and impair thyroid function, and thus could impair
neurological development in utero. We examined human exposures to perchlorate in
the Imperial Valley among individuals consuming locally grown produce and
compared perchlorate exposure doses to state and federal reference doses. We
collected 24-hour urine specimen from a convenience sample of 31 individuals and
measured urinary excretion rates of perchlorate, thiocyanate, nitrate, and
iodide. In addition, drinking water and local produce were also sampled for
perchlorate. All but two of the water samples tested negative for perchlorate.
Perchlorate levels in 79 produce samples ranged from non-detect to 1816 ppb.
Estimated perchlorate doses ranged from 0.02 to 0.51 µg/kg of body
weight/day. Perchlorate dose increased with the number of servings of dairy
products consumed and with estimated perchlorate levels in produce consumed. The
geometric mean perchlorate dose was 70% higher than for the NHANES
reference population. Our sample of 31 Imperial Valley residents had higher
perchlorate dose levels compared with national reference ranges. Although none
of our exposure estimates exceeded the U. S. EPA reference dose, three
participants exceeded the acceptable daily dose as defined by bench mark dose
methods used by the California Office of Environmental Health Hazard
Assessment
Effectiveness of IT-supported patient recruitment: study protocol for an interrupted time series study at ten German university hospitals
Background As part of the German Medical Informatics Initiative, the MIRACUM project establishes data integration centers across ten German university hospitals. The embedded MIRACUM Use Case “Alerting in Care - IT Support for Patient Recruitment”, aims to support the recruitment into clinical trials by automatically querying the repositories for patients satisfying eligibility criteria and presenting them as screening candidates. The objective of this study is to investigate whether the developed recruitment tool has a positive effect on study recruitment within a multi-center environment by increasing the number of participants. Its secondary objective is the measurement of organizational burden and user satisfaction of the provided IT solution. Methods The study uses an Interrupted Time Series Design with a duration of 15 months. All trials start in the control phase of randomized length with regular recruitment and change to the intervention phase with additional IT support. The intervention consists of the application of a recruitment-support system which uses patient data collected in general care for screening according to specific criteria. The inclusion and exclusion criteria of all selected trials are translated into a machine-readable format using the OHDSI ATLAS tool. All patient data from the data integration centers is regularly checked against these criteria. The primary outcome is the number of participants recruited per trial and week standardized by the targeted number of participants per week and the expected recruitment duration of the specific trial. Secondary outcomes are usability, usefulness, and efficacy of the recruitment support. Sample size calculation based on simple parallel group assumption can demonstrate an effect size of d =0.57 on a significance level of 5% and a power of 80% with a total number of 100 trials (10 per site). Data describing the included trials and the recruitment process is collected at each site. The primary analysis will be conducted using linear mixed models with the actual recruitment number per week and trial standardized by the expected recruitment number per week and trial as the dependent variable. Discussion The application of an IT-supported recruitment solution developed in the MIRACUM consortium leads to an increased number of recruited participants in studies at German university hospitals. It supports employees engaged in the recruitment of trial participants and is easy to integrate in their daily work.Open Access funding enabled and organized by Projekt DEAL.Friedrich-Alexander-Universität Erlangen-Nürnberg (1041
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