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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.
31

Estudo da mortalidade em trabalhadores da mineração do amianto no Brasil no período de 1940 a 2010 / Study of mortality in asbestos mining workers in Brazil in the period from 1940 to 2010

Friestino, Fernando Simões, 1981- 26 August 2018 (has links)
Orientador: Ericson Bagatin / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-26T01:11:44Z (GMT). No. of bitstreams: 1 Friestino_FernandoSimoes_M.pdf: 3256668 bytes, checksum: 1a5ab3a1ce5d99130355669ac4a7fd5f (MD5) Previous issue date: 2014 / Resumo: Introdução:O asbesto é uma fibra mineral utilizada por suas características distintas, e usada como matéria-prima para produtos na indústria têxtil e construção civil. O asbesto é considerado carcinogênico para humanos. O Brasil está entre os quatro maiores produtores mundiais. Há diversos trabalhos internacionais relacionando a exposição ocupacional a este agente com doenças das vias aéreas. Entretanto não há estudos de mortalidade entre os trabalhadores expostos no Brasil. Objetivos: Estudar a mortalidade entre os trabalhadores expostos ao asbesto no Brasil, na atividade de mineração. Métodos: Os trabalhadores foram divididos em dois grupos, de acordo com o tipo de exposição que tiveram. O primeiro grupo foi composto pelos trabalhadores expostos entre 1940 e 1980. O segundo foi composto pelos trabalhadores admitidos após 1980. Foram consultadas as declarações de óbito dos ex-trabalhadores para se estabelecer a causa básica do óbito. Foram codificados para a CID-10, para posterior análise descritiva. Resultados:Dos 616 casos estudados, foi possível estabelecer a causa básica do óbito em 429. O grupo exposto à maior carga de amianto apresentou menor proporção de mortes por doenças relacionadas ao asbesto. Conclusões:A exposição ocupacional apontou maior proporção de mortes no grupo com menor exposição, e isto pode estar relacionado com a qualidade da informação disponível.A qualidade da informação foi um fator limitante do estudo / Abstract: Introduction: Asbestos is a mineral fiber used for its distinct characteristics, as raw material for products in the textile industry and construction. Asbestos is considered carcinogenic to humans. Brazil is among the four largest global producers. There are many international studies relating occupational exposure to airway diseases. However, there are no studies of mortality among exposed workers in Brazil. Objectives: To investigate mortality among workers exposed to asbestos in Brazil, in mining activity. Methods: The workers were divided into two groups according to the type of exposure. The death certificates of former employees with underlying cause of death were consulted. They were coded to ICD-10 for further descriptive analysis. Results: Of the 616 cases studied, it was possible to establish the cause of death in 429.The group exposed to the greater burden of asbestos showed a lower proportion of deaths from asbestos-related diseases. Conclusions: The quality of information was a limitation of the study. Occupational exposure showed higher proportion of deaths in the group with less exposure, and this may be related to the quality of information available / Mestrado / Epidemiologia / Mestre em Saude Coletiva
32

Relationship between ferromagnetic particles and airborne chrysotile fibres in the asbestos mines and mills of Quebec

Djamgouz, O. T. January 1982 (has links)
No description available.
33

Fibres in vitro : the importance of pulmonary surfactant, tumour necrosis factor alpha, nitric oxide and ferric iron

Fisher, Carolyn E. January 1999 (has links)
No description available.
34

The effects of mineral fibres on the glutathione homeostasis of lung cells

Rae, Colin James January 2001 (has links)
No description available.
35

Raman spectroscopic studies of asbestos

Russell, K. T. January 1985 (has links)
No description available.
36

Impact of different materials on cracking of corrugated fibrecement sheets

Mtsweni, Ntombikayise Beauty 07 July 2014 (has links)
The replacement of asbestos fibres with cellulose fibres in producing corrugated fibre reinforced cement sheets by the Hatschek process resulted in edge cracking for stacked sheets. This was due to the hydrophilic nature of cellulose, which increases its tendency for exchanging water with the surroundings. The drying process of corrugated sheets, in a stack, resulted in shrinkage hence edge cracking along the sheet. To reduce the magnitude of drying shrinkage and edge cracking potential, several mitigation strategies were proposed including the surface treatment of cellulose fibres, incorporation of wollastonite microfibres, addition of admixtures and superplasticizers, kaolin inclusion as partial replacement of cement and different exposure conditions. A fundamental understanding in mechanisms behind volume changes and how cracks form was crucial for optimization of the mitigation strategies. This thesis initially used a review approach to understand the mechanisms involved in different types of shrinkage and the role of different mitigation techniques. The ultimate goal was to achieve lower drying shrinkage and cracking risks in corrugated sheets along with reducing its economic impact. As a result, surface treatment of cellulose fibres, based on transforming the hydrophilic nature of cellulose to hydrophobic state, was investigated. Furthermore, inclusion of wollastonite/ kaolin as partial replacement of cement, were evaluated. Also, the potential of adding admixtures/ superplasticizers was explored. Finally, investigation on development of edge cracks in stacked corrugated fibrecement sheets was conducted under different exposure conditions. The results and findings of this research showed no significant improvement in permeability with cellulose surface treatment. Wollastonite microfibres promoted pore discontinuity hence significant reduction in permeability thus lower drying shrinkage. However, the resultant sheets were brittle. By reducing water content with addition of superplasticizers, density was enhanced thus reducing volume change from drying and wetting. Kaolin acted as internal restraint for shrinkage, refining the microstructure at the interfacial transition zone thus increasing density and its pozzolanic reaction enhanced mechanical properties. The inclusion of kaolin in the fibrecement mix in conjunction with controlling exposure conditions managed to eliminate edge cracking.
37

The quantitative analysis of components of fibre-reinforced cement boards.

Kuming, Andrew Paul January 1993 (has links)
A Research Report submitted to the Faculty of Architecture, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Building. / Environmental and health considerations have led to the substitution of cellulosic fibres for asbestos fibres in many cement-based products. Inevitably, the substitution has required modifications to the manufacturing process. Certain production techniques associated with the switch to cellulosic fibres and other additives needed elucidation. It is possible that to ensure the required concentration of certalr additives in the final product, an excess is being used in the process because of uncertainties about the quantitative balance of the process. My intention was to examine the potential tole for Fourier Transform Infrared (FTtR) Spectroscopy in the investigation of the materials constituting fibre-reinforced cement boards. I was able to show that qualitative and quantitative determination of certain of the components in the final product are possible with adequate precision and reproducibility to be of value to the manufacturer, I also showed that care taken in the preparation of standard and analytical samples was essential for the success of such analyses. / Andrew Chakane 2018
38

The quantitative analysis of components of fibre-reinforced cement boards.

Kuming, Andrew Paul January 1993 (has links)
A Research Report submitted to the Faculty of Architecture, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Building. / Environmental and health considerations have led to the substitution of cellulosic fibres for asbestos fibres in many cement-based products. Inevitably, the substitution has required modifications to the manufacturing process. Certain production techniques associated with the switch to cellulosic fibres and other additives needed elucidation. It is possible that to ensure the required concentration of certaln additives in the final product, an excess is being used in the process because of uncertainties about the quantitative balance of the process. / Andrew Chakane 2019
39

MECHANISMS OF ASBESTOS-INDUCED CARCINOGENESIS

TOYOKUNI, SHINYA 02 1900 (has links)
No description available.
40

A population-based study of lung cancer and benign intrathoracic tumors

Mäkitaro, R. (Riitta) 04 June 1999 (has links)
Abstract A prospective population-based study was conducted to assess the incidence, diagnosis, histology, treatment and survival of lung cancer in northern Finland. The results were compared with those obtained in a similar survey 20 years earlier. In a population of 440,000, altogether 602 lung cancer patients, 510 men and 92 women, were diagnosed during the years 1990 - 92, the annual incidence per 100,000 being 63 for males and 9.5 for females. Lung cancer was confirmed histologically in 381 cases (63%) and in addition, cytologically in 135 cases (23%). Squamous cell carcinoma was the most common histologic type (40%), the proportion of adenocarcinomas being 26%, small-cell carcinomas 24% and large cell carcinomas 4%. The age-standardized incidence of lung cancer had decreased significantly among males (from 87 to 63 per 100 000) compared to the situation 20 years earlier but increased among females (from 4.1 to 9.5), mainly due to adenocarcinoma. The 5-year survival rate had improved during 20 years from 4% to 12% (p < 0.001). The differences in survival between the histological types (χ2logrank = 59.2, p < 0.0001), TNM stages (χ2logrank = 199.6, p < 0.001), symptomatic stages (χ2logrank = 120, p < 0.001) and treatments (χ2logrank = 277, p < 0.001) were also significant. A total of 20% of the patients were operated on in the newer series of patients, the corresponding percentage in the earlier series being 16%. The 5-year survival of the patients who had been operated on had increased from 23% to 48%. The survival of patients with non-small-cell lung carcinoma had increased significantly, even though the patients were older now than earlier.In seventy operated lung cancer patients, the histological tumor types and grades were compared with the etiological factors of lung carcinoma, including cigarette smoking and asbestos exposure. A majority of the patients (93%) were smokers. The incidence of adenocarcinoma among non-smokers had remained the same, 50%. The accumulation of the p53 protein in lung carcinoma was associated with heavy smoking. Exposure to asbestos fibers either by a positive history or by a number of asbestos bodies (AB) in the histological sections of lung tissue was also associated with p53 accumulation. Benign intrathoracic tumors are uncommon, and their occurrence in unselected populations is poorly defined. Thirty-six benign intrathoracic tumors were found. A histologic diagnosis was available for 24 (67%). Hamartoma was the most common benign lung tumor.

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