• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 13
  • 7
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 26
  • 26
  • 9
  • 6
  • 5
  • 5
  • 5
  • 5
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 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.
11

Particulate distribution and relationship to endotoxin in poultry production operations

Kirychuk, Shelley 05 June 2008
This thesis dissertation assessed workers who work in poultry barns and their occupational environment in relation to the type of bird housing in which they were exposed (cage-housed birds (CH) or floor-housed birds (FH)) and examined the environmental variables including dust and endotoxin and potential relationships to respiratory symptoms of workers. <p>A cross sectional study was undertaken to assess the environmental exposure levels and respiratory health effects of workers who worked in CH and FH poultry operations. The respiratory results suggested an asthma-like syndrome in these workers. Workers who worked in CH facilities reported greater current and chronic respiratory symptoms and significantly greater current and chronic phlegm as compared to workers from FH facilities. Workers from CH poultry facilities were exposed to greater endotoxin load than workers from FH facilities, but workers from FH operations were exposed to greater levels of total dust. It was found that endotoxin load (EU/mg) was a significant predictor of chronic phlegm for all poultry workers.<p>The effects on dust and endotoxin measurements when utilizing a Marple impactor with greased or ungreased impaction surfaces when sampling in an agricultural environment were unknown, and the potential for effects was tested. There were no significant differences in the aerosol mass median aerodynamic diameters between the greased and ungreased Marple impactors. Endotoxin analysis results appeared to be influenced by impaction grease particularly when very low amounts of endotoxin were present. <p>Size fractioning the dust and endotoxin using Marple impactors in CH and FH poultry operations showed that endotoxin load (EU/mg) was significantly higher in the respirable fraction of area samples in CH poultry operations as compared to FH operations. There were no differences in endotoxin load in the non-respirable size fractions for area samples between CH and FH operations. FH poultry operations had significantly greater dust mass and dust concentration in both respirable and non-respirable fractions for FH operations. There was significantly greater endotoxin load (EU/mg) in the 3.5-6.0 micron size fraction for the CH poultry operations as compared to the FH operations.
12

Particulate distribution and relationship to endotoxin in poultry production operations

Kirychuk, Shelley 05 June 2008 (has links)
This thesis dissertation assessed workers who work in poultry barns and their occupational environment in relation to the type of bird housing in which they were exposed (cage-housed birds (CH) or floor-housed birds (FH)) and examined the environmental variables including dust and endotoxin and potential relationships to respiratory symptoms of workers. <p>A cross sectional study was undertaken to assess the environmental exposure levels and respiratory health effects of workers who worked in CH and FH poultry operations. The respiratory results suggested an asthma-like syndrome in these workers. Workers who worked in CH facilities reported greater current and chronic respiratory symptoms and significantly greater current and chronic phlegm as compared to workers from FH facilities. Workers from CH poultry facilities were exposed to greater endotoxin load than workers from FH facilities, but workers from FH operations were exposed to greater levels of total dust. It was found that endotoxin load (EU/mg) was a significant predictor of chronic phlegm for all poultry workers.<p>The effects on dust and endotoxin measurements when utilizing a Marple impactor with greased or ungreased impaction surfaces when sampling in an agricultural environment were unknown, and the potential for effects was tested. There were no significant differences in the aerosol mass median aerodynamic diameters between the greased and ungreased Marple impactors. Endotoxin analysis results appeared to be influenced by impaction grease particularly when very low amounts of endotoxin were present. <p>Size fractioning the dust and endotoxin using Marple impactors in CH and FH poultry operations showed that endotoxin load (EU/mg) was significantly higher in the respirable fraction of area samples in CH poultry operations as compared to FH operations. There were no differences in endotoxin load in the non-respirable size fractions for area samples between CH and FH operations. FH poultry operations had significantly greater dust mass and dust concentration in both respirable and non-respirable fractions for FH operations. There was significantly greater endotoxin load (EU/mg) in the 3.5-6.0 micron size fraction for the CH poultry operations as compared to the FH operations.
13

Occupational air pollutants and non-malignant respiratory disorders especially in miners : thesis IX

Hedlund, Ulf January 2008 (has links)
Aim. To assess associations between occupational air pollution and respiratory health, especially in miners. Background. Indications of associations between occupational exposure or social economic status and respiratory health have been found in several population-based studies. However, there have been few longitudinal studies of the putative correlations, the effects of environmental and genetic factors have seldom been simultaneously studied, and studies of miners have generated conflicting results. Material and methods. Population-based Obstructive Lung Disease in Northern Sweden (OLIN) cohorts surveyed in 1986, 1992 and 1996, and two industry-based materials, were used in cross-sectional and longitudinal studies. Inflammatory markers were compared in sputa from miners after a vacation of at least four weeks, after repeated occupational exposures for at least three months, and controls. The mortality from silicosis was studied in 7729 miners with at least 1 year of exposure. Multivariate analyses were used to adjust for confounders. Results. Up to about 30-40% (etiologic fraction) of incident symptoms in persons both with and without a family history of asthma (FHA) could be explained by exposure to occupational air pollution. Low socio-economic status (SES) was associated with impaired respiratory health. Population attributable risks for most examined disorders were about 10%. Current and ex-miners had increased prevalence of recurrent wheeze, longstanding cough, physician-diagnosed chronic bronchitis, and a trend for increased sputum production. For physician-diagnosed chronic bronchitis a multiplicative interaction was found between exposure and smoking habits. Ex-miners that had been exposed for on average 13 years and whose exposure had ceased 16 years before the study had an increased prevalence of physician-diagnosed chronic bronchitis and chronic productive cough and a trend to increased use of asthma medicines. Miners exposed underground for 18 years, on average, to diesel exhaust (with 0.28 mg/m3 nitrogen dioxide and 27 μg/m3 elemental carbon on average, EC) and particles (3.2 mg/m3 inhalable dust on average) had signs of higher inflammatory activity in their airways, i.e. significantly higher frequencies of macrophages, neutrophils, and total cells compared with referents. The activity in miners was similar after a vacation of at least four weeks and after repeated exposures for three months. There were 58 deaths from silicosis (underlying and contributing cause of death) and a clear dose-response relationship. The data indicated an increased risk of severe silicosis after long-term exposure to 0.1 mg/m3 respirable quartz, the current maximum allowable concentration (MAC) in Sweden and many other countries. Conclusion. Occupational exposure to dust, gases, and fumes impaired respiratory health, accounting for up to 30-40% of some respiratory symptoms in the general population. Low socio-economic status was associated with impaired respiratory health. The complex profiles of dust and diesel exhaust substances found in mines may cause inflammatory reactions in their lungs and persistent respiratory symptoms in occupationally exposed miners. Long-term exposure to quartz at the present MAC level may cause severe silicosis.
14

Predictors of in-race illness in dogsled drivers during the 1000-mile Iditarod Trail Sled Dog Race

Blakeson, Magdalene January 2020 (has links)
No description available.
15

The Effect of ambient air quality on lung function, respiratory symptoms and bronchodilator use among symptomatic children

Fryer, Jayne Louise January 2006 (has links)
Masters Research - Master of Medical Science / Numerous overseas studies have linked both short and long-term exposures to outdoor air pollution to a range of health effects. The differences in air pollution sources, climate and geography in Australia challenged the generalisability of these overseas findings to the Australian setting. In response, the Hunter Illawarra Study of Airways and Air Pollution (HISAAP) was undertaken. The aim of Phase II of HISAAP was to assess the short-term effects of particulates on respiratory health amongst symptomatic children. This thesis presents the results of an analysis of the 345 primary school children eligible for Phase II of the Hunter component of HISAAP. There were multiple daily diary measures on each child, different types of outcomes such as continuous, dichotomous and count variables, as well as several sources of exposure data on pollutants. Because of the complex and hierarchical nature of data, there are several possible methods of analyses that could be used. The thesis begins with a description of the sampling methods used in the study. Next, an overview of the literature on the relationship between air pollution and respiratory health, followed by a review of the methods of analyses appropriate for longitudinal diary studies of this nature. The methods and results are then presented for the analyses of the association between the three main outcomes of interest – evening peak flow, day cough and bronchodilator use – and air quality variables: particulates (PM10 and TSP), sulphur dioxide, pollens and fungi, using three modelling approaches. These include a representative of data reduction methods (Aggregate analysis), subject-specific or mixed-model methods (Korn-Whittemore analysis) and marginal methods (Generalised Estimating Equations). All estimates were adjusted for climate-related covariates and trend. The final chapter discusses the advantages and disadvantages of the various methods of analyses, and a recommendation for analytic techniques for further studies.
16

Qualidade do ar e atendimentos médicos de emergência por sintomas respiratórios em crianças residentes em Jacarepaguá, Rio de Janeiro / Air quality and emergency medical consultations related to respiratory symptoms among children living in Jacarepaguá, Rio de Janeiro

Marisa Moura 12 May 2006 (has links)
Apesar da cidade do Rio de Janeiro ser uma das mais importantes metrópoles brasileiras são muito pouco conhecidos os efeitos da exposição aos poluentes atmosféricos na saúde da população carioca. Este trabalho foi idealizado para suprir uma parte desta carência. Os poluentes investigados foram PM10, SO2, NO2, CO e O3 e os desfechos envolveram os atendimentos pediátricos de emergência por sintomas respiratórios em três unidades públicas de saúde de Jacarepaguá, entre abril de 2002 e março de 2003. As variáveis de confusão foram a tendência temporal, sazonalidade, temperatura, umidade relativa do ar, precipitação de chuva e infecções respiratórias. Também foram ajustados os efeitos do calendário, isto é, determinados dias do ano que apresentaram comportamentos anormais como feriados e finais de semana. Houve inúmeras falhas no monitoramento de todos os poluentes e devido ao reduzido volume de dados, optou-se por não incluir o SO2 nas análises. Uma vez que os determinantes e as conseqüências clínicas das exposições aos poluentes atmosféricos são bastante distintos nas vias aérias superiores e nas vias aéreas inferiores, um dos estudos verificou a associação dos poluentes do ar com transtornos nestes dois segmentos. Embora de pequena magnitude, somente o O3 apresentou resultado positivo e estatisticamente significativo, tanto com todos os atendimentos de emergência por queixas respiratórias como com os atendimentos motivados por sintomas nas vias aéreas inferiores. O efeito foi no mesmo dia da exposição (lag 0). No outro estudo, investigou-se a associação dos poluentes do ar com os atendimentos de emergência por sintomas de obstrução brônquica. Neste caso, as crianças foram categorizadads em três faixas etárias. Somente as crianças com idades menores que 2 anos tiveram um resultado positivo e estatisticamente significativo, de expressiva magnitude com PM10. Semelhante efeito foi visto com o O3, embora com significado estatístico limítrofe (p<0,06). Também neste estudo o efeito ocorreu no mesmo dia da exposição. Apesar das falhas no monitoramento, nos dois estudos, os parâmetros da poluição ambiental estiveram associados ao aumento do número de atendimentos pediátricos de emergência por motivos respiratórios em Jacarepaguá. Durante o período de estudos, os níveis de todos os poluentes monitorados permaneceram abaixo dos limites recomendados. / Rio de Janeiro is one of the most important Brazilian cities. Nevertheless, health effects of air pollutants on its population are scarcely known. This study was conduct to cover part of what is lacking on the subject. Air pollutants investigated were PM10, SO2, NO2, CO e O3 and the outcomes were emergency pediatric consultations due to respiratory complaints on 3 public health units, in Jacarepaguá, between April, 2002 and March 2003. Confounding variables were time trends, seasonality, temperature, humidity, rain volume and respiratory infections. Calendar effects (holidays and weekends) were also adjusted, There were several failures on pollutants monitoring, mainly SO2, which was not taken into consideration to this study, due to low amount of data. As determinants and clinical consequences of air pollutants are very different on upper or lower respiratory system, one of the articles estimated the association of air pollutants to ailments on both systems. Only O3 showed a positive and statistically significant result (although small), both related to emergency consultations due to respiratory complaints as to emergency consultations due to lower respiratory symptoms. Effect and exposure occurred on the same day. (lag0). On the second article, association between air pollutants and emergency consultations related to bronchic obstruction was studied. On this case, children were categorized in three groups, according to age. Only children under 2 years showed a strong, positive and statistically significant result with PM10. A similar effect was observed with O3, although with a boundary statistically significant (p<0,06). On this study, effect and exposure occurred on the same day, as well. Despite failures on monitoring, on both studies, environmental pollution parameters were related to an increased number of emergency pediatric consultations due to respiratory complaints in Jacarepaguá. During all period observed, monitored pollutants levels were under recommended limits.
17

Qualidade do ar e atendimentos médicos de emergência por sintomas respiratórios em crianças residentes em Jacarepaguá, Rio de Janeiro / Air quality and emergency medical consultations related to respiratory symptoms among children living in Jacarepaguá, Rio de Janeiro

Marisa Moura 12 May 2006 (has links)
Apesar da cidade do Rio de Janeiro ser uma das mais importantes metrópoles brasileiras são muito pouco conhecidos os efeitos da exposição aos poluentes atmosféricos na saúde da população carioca. Este trabalho foi idealizado para suprir uma parte desta carência. Os poluentes investigados foram PM10, SO2, NO2, CO e O3 e os desfechos envolveram os atendimentos pediátricos de emergência por sintomas respiratórios em três unidades públicas de saúde de Jacarepaguá, entre abril de 2002 e março de 2003. As variáveis de confusão foram a tendência temporal, sazonalidade, temperatura, umidade relativa do ar, precipitação de chuva e infecções respiratórias. Também foram ajustados os efeitos do calendário, isto é, determinados dias do ano que apresentaram comportamentos anormais como feriados e finais de semana. Houve inúmeras falhas no monitoramento de todos os poluentes e devido ao reduzido volume de dados, optou-se por não incluir o SO2 nas análises. Uma vez que os determinantes e as conseqüências clínicas das exposições aos poluentes atmosféricos são bastante distintos nas vias aérias superiores e nas vias aéreas inferiores, um dos estudos verificou a associação dos poluentes do ar com transtornos nestes dois segmentos. Embora de pequena magnitude, somente o O3 apresentou resultado positivo e estatisticamente significativo, tanto com todos os atendimentos de emergência por queixas respiratórias como com os atendimentos motivados por sintomas nas vias aéreas inferiores. O efeito foi no mesmo dia da exposição (lag 0). No outro estudo, investigou-se a associação dos poluentes do ar com os atendimentos de emergência por sintomas de obstrução brônquica. Neste caso, as crianças foram categorizadads em três faixas etárias. Somente as crianças com idades menores que 2 anos tiveram um resultado positivo e estatisticamente significativo, de expressiva magnitude com PM10. Semelhante efeito foi visto com o O3, embora com significado estatístico limítrofe (p<0,06). Também neste estudo o efeito ocorreu no mesmo dia da exposição. Apesar das falhas no monitoramento, nos dois estudos, os parâmetros da poluição ambiental estiveram associados ao aumento do número de atendimentos pediátricos de emergência por motivos respiratórios em Jacarepaguá. Durante o período de estudos, os níveis de todos os poluentes monitorados permaneceram abaixo dos limites recomendados. / Rio de Janeiro is one of the most important Brazilian cities. Nevertheless, health effects of air pollutants on its population are scarcely known. This study was conduct to cover part of what is lacking on the subject. Air pollutants investigated were PM10, SO2, NO2, CO e O3 and the outcomes were emergency pediatric consultations due to respiratory complaints on 3 public health units, in Jacarepaguá, between April, 2002 and March 2003. Confounding variables were time trends, seasonality, temperature, humidity, rain volume and respiratory infections. Calendar effects (holidays and weekends) were also adjusted, There were several failures on pollutants monitoring, mainly SO2, which was not taken into consideration to this study, due to low amount of data. As determinants and clinical consequences of air pollutants are very different on upper or lower respiratory system, one of the articles estimated the association of air pollutants to ailments on both systems. Only O3 showed a positive and statistically significant result (although small), both related to emergency consultations due to respiratory complaints as to emergency consultations due to lower respiratory symptoms. Effect and exposure occurred on the same day. (lag0). On the second article, association between air pollutants and emergency consultations related to bronchic obstruction was studied. On this case, children were categorized in three groups, according to age. Only children under 2 years showed a strong, positive and statistically significant result with PM10. A similar effect was observed with O3, although with a boundary statistically significant (p<0,06). On this study, effect and exposure occurred on the same day, as well. Despite failures on monitoring, on both studies, environmental pollution parameters were related to an increased number of emergency pediatric consultations due to respiratory complaints in Jacarepaguá. During all period observed, monitored pollutants levels were under recommended limits.
18

Fungal DNA, Mould, Dampness and Allergens in Schools and Day Care Centers and Respiratory Health

Cai, Guihong January 2013 (has links)
Day care centers and schools are important environments for children, but few epidemiological studies exist from these environments. Mould, dampness, fungal DNA and allergens levels in these environments and respiratory health effects in school children were investigated in this thesis. In the day care centers studies, Allergen Avoidance Day care Centers (AADCs) and Ordinary Day care Centers were included. One third of the Swedish day care centers had a history of dampness or mould growth. Total fungal DNA levels were positively associated with risk construction buildings, reported dampness/moulds, rotating heat exchangers, linoleum floors and allergens (cat, dog, horse allergen) levels. The two school studies included secondary schools in Johor Bahru, Malaysia and elementary schools from five European countries (Italy, Denmark, Sweden, Norway, and France) (HESE-study). In Malaysia, 13 % of the pupils reported doctor-diagnosed asthma but only 4 % had asthma medication. The prevalence of wheeze in the last 12 months was 10 % in Malaysia and 13 % in the HESE-study. Cough and rhinitis were common among children in the HESE-study. There were associations between fungal DNA and reported dampness or mould growth. Fungal DNA levels and viable mould (VM) concentration in the classrooms were associated with respiratory symptoms (wheeze, rhinitis, cough, daytime breathlessness) in school children. In the HESE-study, associations were found between total fungal DNA, Aspergillus/Penicillium DNA and respiratory symptoms among children. Moreover, Aspergillus versicolor DNA and Streptomyces DNA were associated with respiratory symptoms in Malaysia and the HESE-study, as well as reduced lung function [forced vitality capacity (FVC) and forced expiratory volume in 1 second (FEV1)] among children in the HESE-study. In conclusion, fungal DNA and pet allergens were common in day care centers and schools and respiratory symptoms in school children were common. The associations between VM concentration and fungal DNA levels in the schools and respiratory health effects in school children indicated a need for improvement of these environments. Moreover, risk constructions should be avoided and buildings should be maintained to avoid dampness and microbial growth. Health relevance of microbial exposure and biodiversity needs to be further studied using molecular methods.
19

Asthma and Respiratory Symptoms in Nordic Countries, Environmental and Personal Risk Factors

Gunnbjörnsdóttir, María Ingibjörg January 2006 (has links)
<p>The overall aims of our studies were to identify risk factors for respiratory symptoms and asthma in indoor environment but even to look at some personal risk factors such as body mass index and gastroesophageal reflux. The study population is based on participants of the European Community Respiratory Health Survey I and II. </p><p> In the first study, water damage and visible moulds were reported in 7.4% and 17% of the homes respectively. The combination of water damage and visible moulds was independently associated with attacks of breathlessness when resting and after activity and also to long term cough. In the second study, the prevalence of nocturnal GER increased with higher BMI and the same pattern could be seen for habitual snoring. Reported onset of asthma, wheeze and night-time symptoms increased in prevalence along with the BMI gradient. In the multivariable analysis, obesity and nocturnal GER were independent risk factors for onset of asthma, wheeze and night-time symptoms. Habitual snoring was an independent risk factor for onset of wheeze and night-time symptoms, but not for onset of asthma. In the third study, a total of 18% of the subjects reported indoor dampness in the last 12 months and 27% of the subjects reported indoor dampness since the previous survey. Respiratory symptoms and asthma were significantly more prevalent in individuals exposed to indoor dampness and indoor dampness was a risk factor for respiratory symptoms and asthma after adjusting for possible confounders. Indoor dampness was an independent risk factor for onset of respiratory symptoms but not for asthma onset. Remission of respiratory symptoms was less likely to occur if subjects reported indoor dampness. In the fourth study, the lowest prevalence of atopy and the lowest levels of all indoor allergens, bacteria and moulds were found in Iceland. A positive association was found, between cat allergen exposure and asthma symptoms and between bronchial hyperresponsiveness and the amount of viable mould in indoor air.</p>
20

Asthma and Respiratory Symptoms in Nordic Countries, Environmental and Personal Risk Factors

Gunnbjörnsdóttir, María Ingibjörg January 2006 (has links)
The overall aims of our studies were to identify risk factors for respiratory symptoms and asthma in indoor environment but even to look at some personal risk factors such as body mass index and gastroesophageal reflux. The study population is based on participants of the European Community Respiratory Health Survey I and II. In the first study, water damage and visible moulds were reported in 7.4% and 17% of the homes respectively. The combination of water damage and visible moulds was independently associated with attacks of breathlessness when resting and after activity and also to long term cough. In the second study, the prevalence of nocturnal GER increased with higher BMI and the same pattern could be seen for habitual snoring. Reported onset of asthma, wheeze and night-time symptoms increased in prevalence along with the BMI gradient. In the multivariable analysis, obesity and nocturnal GER were independent risk factors for onset of asthma, wheeze and night-time symptoms. Habitual snoring was an independent risk factor for onset of wheeze and night-time symptoms, but not for onset of asthma. In the third study, a total of 18% of the subjects reported indoor dampness in the last 12 months and 27% of the subjects reported indoor dampness since the previous survey. Respiratory symptoms and asthma were significantly more prevalent in individuals exposed to indoor dampness and indoor dampness was a risk factor for respiratory symptoms and asthma after adjusting for possible confounders. Indoor dampness was an independent risk factor for onset of respiratory symptoms but not for asthma onset. Remission of respiratory symptoms was less likely to occur if subjects reported indoor dampness. In the fourth study, the lowest prevalence of atopy and the lowest levels of all indoor allergens, bacteria and moulds were found in Iceland. A positive association was found, between cat allergen exposure and asthma symptoms and between bronchial hyperresponsiveness and the amount of viable mould in indoor air.

Page generated in 0.0552 seconds