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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Head Start Parent Perspectives on Child Exposure to Secondhand Smoke at Home

Bekie, Christiana Abani 01 January 2018 (has links)
Children exposed to secondhand smoke (SHS) are at risk of developing ear infections, asthma, wheezing, bronchitis, as well as retarded lung growth. Indoor smoking is the main source of children's exposure to SHS. Despite a downward trend in smoking, children from low income families, especially African American and Hispanic children, continue to be exposed to SHS at a higher rate than their wealthier counterparts. This multiple case study explored the perceptions of 15 parents of 3- to 5-year-old children currently enrolled in Head Start regarding children's exposure to SHS. This study relied on the social ecological model, the theory of reasoned action, and harm reduction for understanding the views of parents and protective behaviors aimed at eliminating children's exposure to SHS in their homes. Data were obtained from semistructured individual interviews and document reviews. Data were analyzed inductively through coding to develop themes and thick rich descriptions of each case and a composite of all cases. Although participants were aware that SHS poses serious threats to the health of children, overall, they lacked knowledge of SHS exposure. They also exhibited a lack of awareness of specific illnesses associated with children's exposure to SHS. Findings from this study might help improve parents' understanding of the health risks associated with exposing children to SHS and possibly help reduce the exposure of Head Start children to SHS through the use of contextualized interventions within the Head Start community.
102

The Total Picture: Multiple Chemical Exposures to Pregnant Women in the US – An NHANES Study of Data from 2003 through 2010

Cabana, Teri 01 January 2014 (has links)
INTRODUCTION: Chemical exposures to US pregnant women have been shown to have adverse health impacts on both mother and fetus. A prior paper revealed that US pregnant women in 2003-2004 had widespread exposure to multiple chemicals. The goal of this research is to examine how environmental chemical exposures to US pregnant women have changed from 2003 to 2010 and to look further at the extent of simultaneous exposure to multiple chemicals in US pregnant women using biomonitoring data available through NHANES (the National Health and Nutritional Examination Survey). METHODS: Using available NHANES data from the following cycles (2003-2004, 2005-2006, 2007-2008, 2009-2010), we analyzed how environmental chemical exposures changed over time. Covariates were used and data was weighted to reflect the population of pregnant US women. Each cycle was then compared to the 2003-2004 cycle in order to assess how exposures have changed over time. We then looked at the data in an entirely different fashion. We examined the total number of chemicals detected in a given pregnant woman by chemical group. Finally, we looked at the total number of detects across various chemical groups and used the Fisher Exact Test to study how the distribution of detections changed in 2009-2010 compared to 2003-2004. RESULTS: While at least one-third of the chemicals analyzed showed one cycle that differed, exposure rates of individual chemicals were generally not increasing from 2003-2010. Median number of detections over chemical groups also did not show much difference over time. However, analysis of the change in frequency distributions revealed that, for some chemical groups, the frequency of detects in US pregnant woman significantly increased in 2010 compared to 2003. CONCLUSIONS: Widespread chemical exposures were seen in US pregnant women from 2003 through 2010. The number of chemical analytes detected in US pregnant women’s bodies is rising. Many chemicals studied had similar mechanisms of action and/or similar adverse health outcomes upon exposure which is known to result in a cumulative health effect. This research suggests that we need to focus not only on exposure rates of individual chemicals but also on the overall number of chemicals detected when assessing the overall picture of environmental chemical exposures to pregnant women in the US.
103

Maternal occupational exposure to extremely low frequency magnetic fields and risk of brain tumors in offspring

Li, Pei Zhi. January 2008 (has links)
Background: The causes of childhood brain tumors (CBT) are essentially unknown. Exposure to extremely low frequency magnetic fields (ELF-MF) (3-3000Hz) is an ubiquitous part of modern life. However, very few studies have investigated the possible effect of maternal occupational ELF-MF exposure on CBT and the available findings are inconsistent across studies. / Methods: We examined the role of maternal occupational exposure to ELF-MF shortly before and during pregnancy on the incidence of childhood brain tumors. A total of 548 incident cases and 760 healthy controls recruited between 1980 and 2002 from two Canadian provinces (Quebec and Ontario) were included and their mothers were interviewed. Tumors were classified as astroglial tumors, primitive neuroectodermal tumors (PNET), and other gliomas. Quantitative occupational ELF-MF exposure in microtesla units was estimated using individual exposure estimations or a job exposure matrix. We used three metrics to analyze exposure: cumulative, average, and maximum level attained. / Results: Using the average exposure metric measured before conception, an increased risk was observed for astroglial tumors (OR=1.5, and 95% CI=1.0-2.4). During the entire pregnancy period, a significantly increased risk was observed for astroglial tumors as well as for all childhood brain tumors with the average metric (OR=1.6, 95% CI=1.1-2.5 and OR=1.5; 95% CI=1.1-2.2, respectively). Based on job titles, a two-fold risk increase was observed for astroglial tumors (OR=2.3, 95% CI=0.8-6.3) and for all childhood brain tumors (OR=2.3, 95% CI=1.0-5.4) among sewing machine operators. / Conclusion: Results are suggestive of a possible association between maternal occupational ELF-MF exposure and certain brain tumors in their offspring. / Keywords: brain tumors, occupational exposures, maternal exposures, magnetic fields, childhood cancer, job exposure matrix
104

Large organic aerosols in a human exposure chamber : applications in occupational dermatology and lung medicine /

Lundgren, Lennart, January 2006 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2006. / Härtill 5 uppsatser.
105

Industrial Hygiene Exposure Estimation Accuracy: An Investigation of Micro-Environmental Factors Impacting Exposure

Eturki, Mohamed 01 October 2019 (has links)
No description available.
106

Maternal occupational exposure to extremely low frequency magnetic fields and risk of brain tumors in offspring

Li, Pei Zhi. January 2008 (has links)
No description available.
107

Human exposure assessment of fluoride from tea (Camellia sinensis L.) with specific reference to human bioaccessibility studies

Chan, Laura January 2014 (has links)
This study aims to determine the concentrations of fluoride in UK tea products and their infusions. This is related to the uptake and distribution of fluoride within tea plants Camellia sinensis (L.). Human oral bioaccessibility of fluoride from the consumption of tea infusions was estimated, using an in vitro approach. The possible health significance from fluoride exposure is discussed. Fluoride in tea products and the distribution within the tea plant was determined using a method, involving alkali fused digestion with ion chromatography and a conductivity detector for the instrumentation. For the aqueous infusions and the supernatants in the bioaccessibility experiments, ion selective electrode with a voltmeter was adopted. Mean fluoride concentrations in tea products and their infusions varied significantly (p<0.001; n=3) and were related to the type of tea product and the retail cost. The higher priced teas, such as Darjeeling, Assam and Oolong, had lower fluoride concentrations. The lower priced supermarket Economy ranged teas were significantly higher (p<0.05) in fluoride and exhibited concentrations similar to Chinese Brick tea, which is prepared using mature tea leaves. The higher quality products are prepared by selecting the finest tips of tea (buds), whereas an Economy products use coarser harvesting techniques to include mature leaves in the product. Fluoride affinity and tolerance of C. sinensis was assessed by a series of fluoride dosing experiments, ranging from 0 to 200 mg. Following fluoride dosing, a rapid uptake and accumulation occurred throughout the tea plants, resulting in partial necrosis of random leaves. Despite the necrosis, the plants tolerated the fluoride and continued to increase in height, although at a significantly slower rate (p<0.05) compared to the control plants. Accumulation of fluoride was observed to be mostly in the mature leaves followed by younger buds, then the roots. This relates to the part of the plant used to produce the tea types, with mature leaves for Economy products and the buds for the finer teas. The in vitro bioaccessibility assessment of fluoride estimated that over 91.4% of fluoride from a tea infusion is available in the human gastric compartment, with 92.1% in the gastro-intestinal compartment. The addition of milk reduced fluoride absorption in the gastric and gastro-intestinal compartments to 73.8 and 83.1%, respectively, possibly reacting to form calcium fluoride. Despite the percentage bioaccessibility, the concentration of fluoride available for absorption in the human gut was dependent upon choice of tea product. Based on an adult male, the findings suggest that consuming a litre of Economy tea can fulfil or exceed (75 to 120%) the recommended dietary reference intake (DRI) of fluoride at 4 mg a day, but only partially fulfil (25 to 40%) when consuming a more expensive Pure blend such as Assam. With regards to health, tea consumption is a source of fluoride in the diet and is highly available for absorption in the human gut. Tea alone can fulfil an adult fluoride DRI, but is dependent upon choice of tea product. Excess fluoride in the diet can lead to detrimental health effects such as fluorosis of the teeth and skeletal fluorosis and consuming economy branded tea can lead to a higher exposure.
108

GIS Spatial Decision Support for Sustainable Landscape Design

Jackson, Chloe January 2015 (has links)
Sustainable Built Environments Senior Capstone Project- Report and Final Document / The purpose of this study is to create a spatial decision support system for sustainable landscape design in an urban setting. As more and more of the worlds population concentrates in cites, the design of these spaces becomes critical to global sustainability. The built environment exhibits different environmental conditions than its rural or natural counterparts— the following study focuses on building a GIS model of unique sun exposure conditions at a site, and using this model in a spatial decision support system. The system will compare the exposure needs of just over 150 native or near native plants with the exposure availability of Tucson’s Historic Y Building, and provide tailored list for each area. This will allow for design flexibility within sustainable parameters.
109

Exposure to hazardous air pollutants in homes

Hun, Diana Esther 01 September 2010 (has links)
Prior studies have found that human exposure to hazardous air pollutants (HAPs) occurs in homes; however, the depth of these assessments was limited by the extent of the analyzed data. The present Ph.D. dissertation focused on air contaminants of concern in residential buildings, the possible sources of these pollutants, and population subgroups with greater contaminant risk. This research also evaluated the effects of building characteristics and household activity patterns on indoor pollution and risk levels. To this end, an in-depth analysis was performed of data from the Relationships of Indoor, Outdoor and Personal Air (RIOPA) study, one of the most comprehensive exposure assessments to date. Using personal concentrations from the RIOPA study, a cancer risk assessment was performed to identify both important pollutants and populations at higher risk. The analyzed compounds were acetaldehyde, benzene, chloroform, carbon tetrachloride, p-dichlorobenzene (p-DCB), ethylbenzene, formaldehyde, methylene chloride, methyl tert-butyl ether (MTBE), styrene, trichloroethylene and tetrachloroethylene. Results indicate that Hispanics and non-Hispanic whites had median cumulative cancer risks (CCR) of 520×10-6 and 440×10-6, respectively, for which the main contributors were formaldehyde, p-DCB, acetaldehyde, chloroform and benzene. Statistically significant differences in CCR between and within Hispanic and whites were primarily due to exposures to p-DCB. Exposure to formaldehyde was further investigated because this compound was the largest contributor to CCR for 69% of Hispanics and 88% of whites, and because most participants had similar cancer risks from these exposures (median = 260×10-6, coefficient of variance = 28%). Results suggest that the U.S. population may be experiencing chronic exposures because of long-term formaldehyde emissions from pressed-wood materials bound with urea-formaldehyde resins. Source removal may be the most effective way to decrease these chronic exposures. Benzene was also examined further because it is a known human carcinogen. Results show that indoor benzene concentrations increased as the proximity of parked vehicles decreased. Residing in a home with an attached garage could lead to exposures to benzene ten times higher than while commuting in a car in heavy traffic, and with mean excess cancers of 17×10-6. Detached garages could reduce health risks from exposure to benzene and other gasoline-related pollutants. / text
110

The role of emotion in selective exposure, information processing, and attitudinal polarization

Kim, Soohee, 1980- 25 October 2010 (has links)
This thesis reviews the role of emotions in one’s choice of information, information processing, and political attitudes. Theoretical and empirical endeavors to date have focused primarily on how emotions influence attitudes and information processing, leaving the actual processes guiding these outcomes in the margins. Specifically, it has been largely unexplored how emotions influence individuals’ information search behavior and then attitudes and information processing. Noting that the purposeful selection of likeminded information, often referred to as selective exposure, is commonly enacted when an individual first initiates information processing, and is also likely influenced by emotions, this study explores how emotions may affect people’s tendency to seek out congruent information. In addition, this study examines how the relationship between emotions and selective exposure in turn may affect aspects of information processing and attitudes. By designing an online experiment, I first tested how certain negative emotions (anger/fear) affected one’s pursuit of certain types of information (consistent/inconsistent) and second, I investigated how these emotions and information selections influenced subsequent information processing and attitudes. Results showed that while anger motivated more likeminded exposure for Republicans than fear, fear promoted more likeminded exposure for Democrats than anger. Further, anger prompted people to process messages more closely and to develop more polarized attitudes compared to fear. In addition, pro-attitudinal exposure produced more message-relevant thoughts for Republicans than counter-attitudinal message exposure, while it was counter-attitudinal exposure that yielded more message-relevant thoughts for Democrats. No such effect, however, was shown for attitudinal polarization. / text

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