• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 101
  • 30
  • 24
  • 15
  • 6
  • 5
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • Tagged with
  • 226
  • 77
  • 71
  • 69
  • 40
  • 38
  • 34
  • 29
  • 27
  • 22
  • 21
  • 21
  • 17
  • 16
  • 16
  • 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

Intérêt diagnostique de la biopsie liquide dans la prise en charge de l'adénocarcinome canalaire du pancréas à un stade précoce / Diagnostic interest of liquid biopsy in the management of early stage pancreatic ductal adenocarcinoma

Buscail, Etienne 14 June 2019 (has links)
Introduction:Un des problèmes du cancer du Pancréas (CP) est le temps de latence entre la suspicion du CP et la mise en place des traitements. Les méthodes de biopsie liquide pourraient accélérer la mise en évidence d’éléments tumoraux et le diagnostic.Objectif :L’objectif principal de l’étude était de comparer la performance diagnostique de plusieurs techniques de biopsie liquide chez des patients atteint d’un CP résécable d’emblé. L’objectif secondaire était la corrélation avec le taux de récidive post-opératoire.Méthodes:Tout d'abord, nous avons testé 2 méthodes d'enrichissement CTC pour estimer la sensibilité de la détection CTC avec des expériences de cell-spiking de deux lignées de cellules tumorales pancréatiques dans des échantillons de sang de 24 volontaires sains en utilisant la méthode en gradient de densité OncoQuick® et la méthode de sélection négative RosetteSep™. De plus, les mutations KRAS ont été quantifiées dans l'ADN génomique de cellules purifiées par digital droplet PCR (dd-PCR) avec des amorces spécifiques des allèles.Nous avons conçu un essai clinique prospectif (NCT03032913) visant à détecter les cellules tumorales circulantes (CTC), l’ADN tumoral circulant (ADNct) et les onco-exosomes chez les patients atteint de CP et chez les patients d’un groupe témoin. Pour les CTCs : enrichissement et détection de CTCs par la méthode CellSearch©, méthode d’enrichissement de CTCs RosetteSep® et OncoQuick® puis quantification de l’ADN tumoral par dd-PCR. Les exosomes ont été isolés puis caractérisés avec le taux d’expression de Glypican-1. Tous les patients de l’étude ont eu un prélèvement de sang périphérique, les patients du groupe CP ont eu un prélèvement de sang portal peropératoire.Résultats:La sensibilité analytique était de 100 % pour OncoQuick®, quelle que soit la lignée cellulaire, et se situait entre 70 et 100 % pour RosetteSep™. Le taux moyen de récupération des cellules était de 56±23% pour OncoQuick® contre 39±27% pour RosetteSep™ (p<0,001). Les cellules tumorales de la population de cellules sanguines enrichies ont été détectées par dd-PCR après enrichissement par RosetteSep™ et OncoQuick® La détection des allèles K-RAS mutants par ddPCR après enrichissement de RosetteSepTM était 3 à 4 fois plus sensible qu'après OncoQuick®. Ainsi, RosetteSep™ est plus fiable en termes d'efficacité de récupération et de détection des mutants KRAS que OncoQuick®.De février à novembre 2017, 22 patients atteints de CP résécable et 28 patients témoins ont été inclus. Tous les patients ont été détectés positifs par au moins une méthode. Les CTCs ont été détectées chez 9 patients avec la méthode cellsearch (70% dans le sang portal exclusif) et 13 avec la méthode Rosettesep (60%). Les onco-exosomes ont été détecté chez 14 patients sur 22. L’ADNct n’a été détecté que chez deux patients métastatiques. La détection combinée des CTCs et des onco-exosomes était significativement corrélée à la survie sans récidive.Conclusion:Cette étude suggère que la biopsie liquide combinée peut être un outil prometteur à fois diagnostique et pronostique dans le CP à un stade précoce. / Introduction:One of the problems of pancreatic ductal adenocarcinoma (PC) is the latency time between the suspicion of PC and the initiation of treatments, especially neo-adjuvants that require histological evidence. Liquid biopsy methods could be a companion test for diagnosis.Objective :The main objective of the study was to compare the diagnostic performance of several liquid biopsy techniques in patients with resectable pancreatic without neo-adjuvant therapy cancer. The secondary objective was the correlation between the quantification of liquid biopsy parameters and clinic-pathologic features.Methods:First, we tested 2 CTC enrichment methods to estimate the sensitivity of CTC detection with cell spiking experiments of two pancreatic tumour cell lines in blood samples from 24 healthy volunteers using the onco-specific density gradient OncoQuick® and the negative selection enrichment method RosetteSep™. Additionally, KRAS mutations were quantified in genomic DNA of purified cells by digital droplet Q-PCR (dd-PCR) with allele specific primers.We designed a prospective clinical trial (PANC-CTC# NCT03032913) to detect circulating tumour cells (CTC), circulating tumour DNA (ADNct) and onco-exosomes in patients with pancreatic cancer and in patients in a control group using different methods. For CTCs, it was the enrichment and detection of CTCs by the CellSearch© method (reference method), the RosetteSep® and OncoQuick® CTC enrichment method and the quantification of tumor DNA by dd-PCR. Exosomes were isolated and characterized with the expression rate of Glypican-1. All patients in the study had a peripheral blood sample, patients in the PDAC group had a portal blood sample during surgery.Results:Analytical sensitivity was 100% for OncoQuick®, regardless of the cell line, and ranged between 70 and 100% for RosetteSep™. Mean recovery rate of cells was 56±23% for OncoQuick® versus 39±27% for RosetteSep™ (p<0.001). Molecular detection of mutant K-RAS alleles by ddPCR after RosetteSepTM enrichment was 3- to 4-fold more sensitive than after OncoQuick®. Thus, RosetteSep™ is more reliable in terms of recovery efficiency and KRAS mutant detection than OncoQuick®.From February to November 2017, 22 patients with resectable pancreatic cancer and 28 control patients were included. All patients were positive by at least one method. CTCs were detected in 9 patients with the cellsearch method (70% in the exclusive portal blood) and 13 with the Rosettesep method (59%), Onco-exosomes were detected in 14 out of 22(64%) patients in peripheral and/or portal blood. DNAct was detected in only two metastatic patients. The combined detection of CTCs with cellsearch and onco-exosomes was significantly correlated with progression free survival and overall survival when CTC cluster were found.Conclusion: This study suggests that combined liquid biopsy can be a promising tool for both diagnosis and prognosis in early pancreatic cancer.
102

Bioremediation of naphthenic acids in a circulating packed bed bioreactor

Huang, Li Yang 18 August 2011
Naphthenic acids (NAs) comprise a complex mixture of alkyl-substituted acyclic and cycloaliphatic carboxylic acids. NAs are present in wastewaters at petroleum refineries and in the process waters of oil sands extraction plants where they are primarily retained in large tailing ponds in the Athabasca region of Northern Alberta. The toxicity of these waters, primarily caused by NAs, dictates the need for their treatment.Bioremediation is considered as one of the most cost-effective approaches for the treatment of these wastewaters. Ex-situ bioremediation conducted in a bioreactor optimizes the microbial growth and activity by controlling environmental conditions resulting in efficient conversion of the contaminants to less harmful compounds. In this work, a circulating packed bed bioreactor (CPBB), with improved mixing, mass transfer and biomass hold-up has been used to study biodegradation of several model NA compounds: namely trans-4-methyl-1-cyclohexane carboxylic acid (trans-4MCHCA), a mixture of cis- and trans- 4-methyl-cyclohexane acetic acid (4MCHAA), and octanoic acid as well co-biodegradation of these naphthenic acids with octanoic acid, using a mixed culture developed in our laboratory. The biodegradation rates achieved for trans-4MCHCA in the CPBB are far greater than those reported previously in the literatures. The maximum biodegradation rate of trans-4MCHCA observed during batch operation was 43.5 mg/L-h, while a rate of 209 mg/L-h was achieved during continuous operation. Although cis-4MCHAA is more resistant to biodegradation when compared with trans-4MCHCA, the experimental results obtained from this study indicated both isomers were effectively biodegraded in the CPBB, with the maximum biodegradation rates being as high as 2.25 mg/L-h (cis-4MCHAA) and 4.17 mg/L-h (trans-4MCHAA) during batch operations and 4.17 mg/L-h(cis-4MCHAA) and 7.80 mg/L-h (trans-4MCHAA) during the continuous operation. Optimum temperature for biodegradation of 4MCHAA was determined as 25 aC. Furthermore, the biodegradation rate of single ring NAs (trans-4MCHCA and 4MCHAA) were found to be significantly improved through utilization of octanoic acid as a co-substrate. For example, the maximum biodegradation rate of trans-4MCHCA obtained during batch operation with the presence of octanoic acid was 112 mg/L-h, which was 2.6 times faster than the maximum value of 43.5 mg/L-h when trans-4MCHCA was used as a sole substrate. Similarly, the highest biodegradation rates of cis-4MCHAA and trans-4MCHAA were 16.7 and 28.4 mg/L-h in the presence of octanoic acid, which were 7.4 and 6.8 times higher than the maximum rates of 2.25 and 4.17 mg/L-h in the absence of octanoic acid.
103

Bioremediation of naphthenic acids in a circulating packed bed bioreactor

Huang, Li Yang 18 August 2011 (has links)
Naphthenic acids (NAs) comprise a complex mixture of alkyl-substituted acyclic and cycloaliphatic carboxylic acids. NAs are present in wastewaters at petroleum refineries and in the process waters of oil sands extraction plants where they are primarily retained in large tailing ponds in the Athabasca region of Northern Alberta. The toxicity of these waters, primarily caused by NAs, dictates the need for their treatment.Bioremediation is considered as one of the most cost-effective approaches for the treatment of these wastewaters. Ex-situ bioremediation conducted in a bioreactor optimizes the microbial growth and activity by controlling environmental conditions resulting in efficient conversion of the contaminants to less harmful compounds. In this work, a circulating packed bed bioreactor (CPBB), with improved mixing, mass transfer and biomass hold-up has been used to study biodegradation of several model NA compounds: namely trans-4-methyl-1-cyclohexane carboxylic acid (trans-4MCHCA), a mixture of cis- and trans- 4-methyl-cyclohexane acetic acid (4MCHAA), and octanoic acid as well co-biodegradation of these naphthenic acids with octanoic acid, using a mixed culture developed in our laboratory. The biodegradation rates achieved for trans-4MCHCA in the CPBB are far greater than those reported previously in the literatures. The maximum biodegradation rate of trans-4MCHCA observed during batch operation was 43.5 mg/L-h, while a rate of 209 mg/L-h was achieved during continuous operation. Although cis-4MCHAA is more resistant to biodegradation when compared with trans-4MCHCA, the experimental results obtained from this study indicated both isomers were effectively biodegraded in the CPBB, with the maximum biodegradation rates being as high as 2.25 mg/L-h (cis-4MCHAA) and 4.17 mg/L-h (trans-4MCHAA) during batch operations and 4.17 mg/L-h(cis-4MCHAA) and 7.80 mg/L-h (trans-4MCHAA) during the continuous operation. Optimum temperature for biodegradation of 4MCHAA was determined as 25 aC. Furthermore, the biodegradation rate of single ring NAs (trans-4MCHCA and 4MCHAA) were found to be significantly improved through utilization of octanoic acid as a co-substrate. For example, the maximum biodegradation rate of trans-4MCHCA obtained during batch operation with the presence of octanoic acid was 112 mg/L-h, which was 2.6 times faster than the maximum value of 43.5 mg/L-h when trans-4MCHCA was used as a sole substrate. Similarly, the highest biodegradation rates of cis-4MCHAA and trans-4MCHAA were 16.7 and 28.4 mg/L-h in the presence of octanoic acid, which were 7.4 and 6.8 times higher than the maximum rates of 2.25 and 4.17 mg/L-h in the absence of octanoic acid.
104

Performance Improvements to a Fast Internally Circulating Fluidised Bed (FICFB) Biomass Gasifier for Combined Heat and Power Plants

Bull, Douglas Rutherford January 2008 (has links)
This thesis describes the development and experimental testing of a 100 kW dual fluidized bed biomass gasifier (also called a Fast Internally Circulating Fluidized Bed (FICFB) biomass gasifier). This steam-blown gasifier is being studied for its suitability within combined heat and power plant systems for the New Zealand forest products industry. This advanced design of gasifier has the ability to generate producer gas with a lower heating value (LHV) of 11.5-13.4 MJ/Nm3, which is two to three times higher than yielded by conventional gasification systems. This is accomplished because the gasification and combustion processes occur in two physically separated reactors. Several modifications to the gasifier were required after it was first constructed in order to achieve stable and reliable operation. Producer gas yields were measured through the use of helium as a tracer gas. A new simultaneous producer gas and tar sampling system was developed, allowing accurate samples to be obtained in a matter of minutes. Experimental testing included a cold testing exercise which provided valuable information on the circulation behaviour of the bed material and char within the gasifier. This helped in achieving stable and reliable operation of the plant. Producer gas yields of 14.6 Nm3/h were recorded with a fuel (radiate pine wood pellets) feed rate of 18.9 kgdry/h. The cold gas efficiency ranged from 16-40 % with limited heat recovery in place, but depended noticeably on the plant operating conditions especially gasification temperature. The amount of polycyclic aromatic hydrocarbon (PAH) tars measured in the producer gas ranged between 0.9-4.7 g/Nm3 with naphthalene and acenapthylene being the most abundant compounds. The moisture content of the producer gas was determined to be 0.9-1.2 g/gdry gas. It was found that a steam to biomass ratio of 0.45-0.7 kg/kgdry was most favourable for generating a 12-13.4 MJ/Nm3 producer gas while limiting the amount of steam generation. Gasification temperatures above 750 °C encouraged higher producer gas yields and higher cold gas efficiencies. The catalytic bed material olivine (forsterite olivine) was found to increase the producer gas yield by approximately 20 % compared to the non-catalytic bed material greywacke. The use of olivine meant higher cold gas efficiencies were achieved for a given wood feed rate.
105

O método de circulantes, as fórmulas de Cardano e o teorema de Fermat para n=3

Melo, Rômulo de Oliveira Lins Vieira de 31 August 2017 (has links)
Submitted by Leonardo Cavalcante (leo.ocavalcante@gmail.com) on 2018-05-02T18:31:29Z No. of bitstreams: 1 Arquivototal.pdf: 790723 bytes, checksum: 7e439258b05733c014dcd3e7de230c1f (MD5) / Made available in DSpace on 2018-05-02T18:31:29Z (GMT). No. of bitstreams: 1 Arquivototal.pdf: 790723 bytes, checksum: 7e439258b05733c014dcd3e7de230c1f (MD5) Previous issue date: 2017-08-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this present work, principles and theorems associated to integers are returned, as well as eigenvalues and eigenvectors problems, highlighting a Hermitian matrix. Then it is emphasized to the Circulating Matrices, through which it is found the association to two well-defined polynomials: the representative and the characteristic. Later a brief account about the history of polynomial equations is made, drafting the Cardano-Tartaglia Formulas associated to them. Afterwards a unification is made in the resolution process of the polynomial equations of smaller degrees than the equal to 4, by means of the circulating matrices. The work is completed by proving a Fermat theorem for n = 3, using the Cardano-Tartaglia Formulas. / No presente trabalho, princípios e teoremas associados aos números inteiros são retomados, bem como problemas de autovalores e autovetores, sendo ressaltada a matriz Hermitiana. Em seguida é dado ênfase às Matrizes Circulantes, através das quais verifica-se a associação a dois polinômios bem definidos: o representante e o característico. Posteriormente realiza-se um breve relato acerca da história das equações polinomiais, destacandose as Fórmulas de Cardano-Tartaglia associadas às mesmas. Logo após é feita uma unificação no processo de resolução das equações polinomiais de graus menores do que o igual a 4, por meio das matrizes circulantes. O trabalho é finalizado, sendo provado o Teorema de Fermat para n = 3, recorrendo-se às Fórmulas de Cardano-Tartaglia.
106

Cardiotoxicity from cancer therapy : a translational approach to biomarker development

Cove-Smith, Laura Suzanne January 2015 (has links)
Background: Heart damage from cancer therapy is a significant problem for survivors. Some of the most effective treatments, such as anthracyclines, cause heart toxicity that can lead to significant morbidity and mortality. Cardiotoxicity also contributes to the loss of promising cancer drugs in early development and is notoriously difficult to predict. This translational project employs parallel pre-clinical and clinical studies to explore circulating biomarkers and cardiac magnetic resonance imaging (CMR) during development of anthracycline associated cardiotoxicity with the aim of finding biomarkers to aid clinical decision making and enable forward/back translation. Methods: Pre-clinical work: A rat model of chronic anthracycline-induced cardiomyopathy was developed involving 8 weekly intravenous boluses of doxorubicin followed by a 4 week ‘washout’ period. A time course assessment of cardiac function using multiple MRI parameters was performed alongside a panel of circulating biomarkers measured prior to dosing. Clinical work: In parallel following ethical approval, 30 cancer patients receiving standard anthracycline chemotherapy were recruited. Serial CMR scans were performed using standard and new exploratory techniques before, during and after treatment and blood was taken to evaluate a similar panel of cardiotoxicity biomarkers using multiplex ELISA at corresponding time points. Results: Pre-clinical results: Systolic and diastolic function declined progressively, culminating in left ventricular dysfunction (LVEF < 50%) by 12 weeks. Myocardial electron microscopy revealed myofibrillar and mitochondrial damage after one dose and gross histopathological damage after 5 doses. Myocardial contrast enhancement and troponin I increased significantly after eight doses and preceded LV dysfunction. Extensive fibrosis was seen 1 month after drug cessation. Clinical results: LVEF declined progressively in all patients and 7 patients (23%) had persistent LV dysfunction 12 months after therapy. Troponin I elevations were seen towards the end of therapy and peak troponin I corresponded with LVEF decline. None of the other circulating biomarkers correlated strongly with outcome. Lower baseline extracellular volume (ECV) was associated with greater LVEF decline but little change in ECV was seen over time. Baseline dyssynchrony was associated with worse outcome and deteriorated with time alongside LVEF decline. Conclusions: Results suggest that troponin I and cardiac MRI are sensitive translational tools in drug induced cardiotoxicity. However, troponin I is a relatively late marker, peaking after substantial myocardial damage, too late to halt or change reatment. The imaging suggests that fibrosis and inflammation cannot be detected within a year of chemotherapy but baseline ECV and strain analysis may have a role in risk stratification.
107

Construções e redefinições: as toxoplasmoses / Redefinitions and constructions: the Toxoplasmosis

Vera Lúcia Marques da Silva 20 May 2008 (has links)
Esta tese tem como objeto o processo de redefinição da categoria diagnóstica infecção/doença Toxoplasmose. É um estudo qualitativo, inserido no campo science studies, de abordagem crítica reformista e de natureza empírico-analítica. Vincula-se à linha de pesquisa intitulada Instituições, saberes e práticas em saúde e ao projeto Os médicos e a ciência do Instituto de Medicina Social da Universidade do Estado do Rio de Janeiro. As unidades de análise foram: 1) Agentes envolvidos na produção do conhecimento científico em nível local; 2) Documentos normativos locais; 3) Documentos normativos nacionais e internacionais; 4) Instituição: Laboratório Reconhecer do Centro de Biociências e Biotecnologia (CBB), da Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF/Darcy Ribeiro). Como técnicas de pesquisa foram utilizadas a observação etnográfica, entrevistas e pesquisa documental da produção científica. Os pressupostos foram de que essa redefinição seja decorrente de uma construção (Hacking, 1999; Latour, 1997, 2000, 2001) e realizada em uma arena transepistêmica (Knor-Cetina, 1981). Foram acrescidos a esses conceitos, os de referência circulante (Latour, 2001) e os da taxonomia dos elementos dos objetos da ciência laboratorial, ou seja, os conceitos idéias, marcas e coisas (Hacking, 1992). Considerando essa dinâmica, as redefinições em relação a essa infecção/doença estariam em um período de pouca estabilização, embora elas não se definiriam completa e eternamente pela dependência que possuem do invólucro espaço-temporal (Latour, 2001) e da referência circulante. / This thesis has as object the process of redefinition of the disgnostic category infection/illness "Toxoplasmosis". It is a qualitative, inserted study in the field "science studies", of reformist critical boarding and empiricist-analytical nature. The line of intitled research is associated to it "Institutions, to know and practical in health" and to the project "the doctors and the science" of the Institute of Social Medicine of the University of the State of Rio De Janeiro. The units of analysis had been: 1) "involved Agents" in the production of the scientific knowledge in local level; 2) local normative Documents; 3) national and international normative Documents; 4) Institution: Laboratory To recognize of the Center of Biosciences and Biotechnology (CBB), of the State University of the Of the state of Rio de Janeiro North Darcy Ribeiro (UENF/Darcy Ribeiro). As research techniques had been used the etnografic observation, interviews and documentary research of scientific production. The estimated ones had been of that this redefinition is decurrent of a "construction" (Hacking, 1999; Latour, 1997, 2000, 2001) and carried through in a "transepistemic arenas" (Knor- Cetina, 1981). They had been increased to these concepts, of circulating reference (Latour, 2001) and of the taxonomy of the elements of objects of laboratorial science, that is, the concepts ideas, marks and things (Hacking, 1992). Considering this dynamics, the redefinitions in relation to this infection/illness would be in a period of little stabilization, even so they are not defined completely and perpetual for the dependence that possess of the "pack space-weather" (Latour, 2001) and of the "circulating reference".
108

Construções e redefinições: as toxoplasmoses / Redefinitions and constructions: the Toxoplasmosis

Vera Lúcia Marques da Silva 20 May 2008 (has links)
Esta tese tem como objeto o processo de redefinição da categoria diagnóstica infecção/doença Toxoplasmose. É um estudo qualitativo, inserido no campo science studies, de abordagem crítica reformista e de natureza empírico-analítica. Vincula-se à linha de pesquisa intitulada Instituições, saberes e práticas em saúde e ao projeto Os médicos e a ciência do Instituto de Medicina Social da Universidade do Estado do Rio de Janeiro. As unidades de análise foram: 1) Agentes envolvidos na produção do conhecimento científico em nível local; 2) Documentos normativos locais; 3) Documentos normativos nacionais e internacionais; 4) Instituição: Laboratório Reconhecer do Centro de Biociências e Biotecnologia (CBB), da Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF/Darcy Ribeiro). Como técnicas de pesquisa foram utilizadas a observação etnográfica, entrevistas e pesquisa documental da produção científica. Os pressupostos foram de que essa redefinição seja decorrente de uma construção (Hacking, 1999; Latour, 1997, 2000, 2001) e realizada em uma arena transepistêmica (Knor-Cetina, 1981). Foram acrescidos a esses conceitos, os de referência circulante (Latour, 2001) e os da taxonomia dos elementos dos objetos da ciência laboratorial, ou seja, os conceitos idéias, marcas e coisas (Hacking, 1992). Considerando essa dinâmica, as redefinições em relação a essa infecção/doença estariam em um período de pouca estabilização, embora elas não se definiriam completa e eternamente pela dependência que possuem do invólucro espaço-temporal (Latour, 2001) e da referência circulante. / This thesis has as object the process of redefinition of the disgnostic category infection/illness "Toxoplasmosis". It is a qualitative, inserted study in the field "science studies", of reformist critical boarding and empiricist-analytical nature. The line of intitled research is associated to it "Institutions, to know and practical in health" and to the project "the doctors and the science" of the Institute of Social Medicine of the University of the State of Rio De Janeiro. The units of analysis had been: 1) "involved Agents" in the production of the scientific knowledge in local level; 2) local normative Documents; 3) national and international normative Documents; 4) Institution: Laboratory To recognize of the Center of Biosciences and Biotechnology (CBB), of the State University of the Of the state of Rio de Janeiro North Darcy Ribeiro (UENF/Darcy Ribeiro). As research techniques had been used the etnografic observation, interviews and documentary research of scientific production. The estimated ones had been of that this redefinition is decurrent of a "construction" (Hacking, 1999; Latour, 1997, 2000, 2001) and carried through in a "transepistemic arenas" (Knor- Cetina, 1981). They had been increased to these concepts, of circulating reference (Latour, 2001) and of the taxonomy of the elements of objects of laboratorial science, that is, the concepts ideas, marks and things (Hacking, 1992). Considering this dynamics, the redefinitions in relation to this infection/illness would be in a period of little stabilization, even so they are not defined completely and perpetual for the dependence that possess of the "pack space-weather" (Latour, 2001) and of the "circulating reference".
109

Avaliação das emissões de S'O IND.2' em leito fluidizado circulante na combustão de carvão mineral brasileiro e dolomita / Evaluation of S'O IND.2' emissions from brazilian mineral coal combustion with dolomite in circulating fluidized bed.

Hory, Rogerio Ishikawa 27 July 2007 (has links)
Orientador: Arai Augusta Bernardez Pecora / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-11T13:29:17Z (GMT). No. of bitstreams: 1 Hory_RogerioIshikawa_D.pdf: 3549862 bytes, checksum: 727c6ab5dce7454b6af9546842232b2e (MD5) Previous issue date: 2007 / Resumo: Este trabalho apresenta o estudo experimental do processo de combustão de carvão mineral brasileiro em reator de Leito Fluidizado Circulante (LFC) com o objetivo de avaliar as taxas de emissões de di óxido de enxofre (S02) e eficiência de conversão de carbono no processo de combustão. Para diminuir a emissão do S02 nos gases de exaustão, foi adicionado, ao carvão, quantidades de calcário dolomítico (dolomita), de modo que a relação molar entre o cálcio (Ca) presente no calcário e o enxofre (S) presente no carvão variou entre 0,0 e 2,0. A variação na relação molar Ca/S, como é denominada na literatura, foi um dos dois fatores avaliados neste trabalho. O outro fator envolvido nos testes foi o excesso de ar utilizado para combustão do carvão. Trabalhou-se com excesso de ar na faixa de 20 a 30%. Foram realizados 11 ensaios seguindo um planejamento experimental estatístico do tipo CCD (Composite Central Design) e mais 02 ensaios complementares. A relação molar Ca/S de 0,6 apresentou emissão zero de S02 e propôs-se utilizar uma nova relação molar: (Ca+Mg)/S para retratar processos de sorção com dolomitas. Para emissão zero de S02, uma relação molar (Ca+Mg)/S de 1,8 já é suficiente. Foram obtidas eficiências de conversão do carbono entre 86,0 e 93,0% para combustão do carvão / Abstract: This work presents an experimental study with Brazilian mineral coal combustion in a Circulating Fluidized Bed (CFB) reactor with the objective to evaluate the sulphur dioxide emissions (S02) and the carbon conversion efficiency in the combustion processo Dolomite was added to the coal to minimize the S02 emissions during combustion. The quantity of dolomite added was calculated based on the molar relation of calcium (Ca) present in the dolomite and sulphur (S) present in the coal. Ca/S molar relation had a variation between 0,0 and 2,0. Two factors were evaluated in this work: Ca/S relation and excess of air during combustion which had a variation between 20 and 30%. Eleven (11) experimental tests were evaluated following a statistical experimental design called CCD (Composite Central Design) and 02 (two) more complementary tests. Emissions of S02 with zero value were obtained for a Ca/S of 0,6. It was also proposed in this work a new relation for sorption of S02 with dolomite: (Ca+Mg)/S relation. Tests showed that a relation of 1.8 for (Ca+Mg)/S is sufficient for zero emissions of S02. Carbon conversion efficiency between 86.0 and 93.0 was also obtained during coal combustion / Doutorado / Termica e Fluidos / Mestre em Engenharia Mecânica
110

Consumo alimentar e concentrações séricas de micronutrientes: associação com lesões neoplásicas e câncer cervical / Diet and serum micronutrientes: association with cervical neoplasia and cancer

Luciana Yuki Tomita 19 October 2007 (has links)
O câncer cervical é o segundo câncer mais comum entre as mulheres em todo o mundo. A infecção por Papilomavirus (HPV) do tipo oncogênico é causa necessária. Estudos internacionais sugerem importante papel de carotenóides e tocoferóis séricos e dietéticos na redução do risco para lesões precursoras, mas os resultados dos estudos prévios são inconsistentes. Indivíduos e métodos: O presente estudo de casos e controles de base hospitalar conduzido na cidade de São Paulo analisou a associação entre concentrações séricas de carotenóides (licopeno, &#946;-caroteno), tocoferóis (&#945;- e &#947;-), consumo alimentar e casos incidentes, com confirmação histopatológica, de neoplasia intraepitelial cervical (NIC) graus 1,2,3 e câncer cervical. O estudo incluiu 453 mulheres do grupo controle (sem lesões de colo uterino) e 4 grupos de casos (NIC1, n=140; NIC2, n=126; NIC3, n=231; câncer cervical, n=108) recrutadas em dois hospitais públicos de referência entre 2003 e 2005. Resultados. A concentração sérica de licopeno foi inversamente associada à NIC1, NIC3 e câncer cervical com os seguintes Odds Ratio (OR) (intervalo de confiança de 95%), respectivamente: 0,53 (0,27-1,00; p de tendência=0,05); 0,48 (0,22-1,04; p de tendência=0,05) e 0,18 (0,06-0,52; p de tendência=0,002) quando comparado o maior com o menor tercil após ajuste por variáveis de confusão e grupos de HPV. O maior tercil de &#946;-caroteno sérico foi inversamente associado ao câncer quando comparado ao menor: OR ajustado = 0,36 (0,13-1,03: p de tendência=0,04). Maiores concentrações de &#945;- e &#947;-tocoferóis foram inversamente associadas a NIC3 com redução do risco em 50%, após ajuste por covariáveis e HPV. Maior tercil de consumo do grupo de folhas verde-escuras, legumes e frutas de cor alaranjada ou amarela escura foi inversamente associado ao risco para NIC3: OR ajustado comparado ao menor foi 0,52 (0,27-1,00; p de tendência=0,05). Conclusão: Os resultados do presente estudo sugerem que maiores concentrações séricas de antioxidantes e o consumo de alimentos ricos em carotenóides podem reduzir o risco para NIC3 e câncer cervical em mulheres brasileiras. / Cervical cancer is the second most common cancer in women worldwide. Human papillomavirus (HPV) infection has been recognized to be a necessary cause for cervical cancer. Serum concentrations and dietary carotenoids and tocopherols have been associated with the risk for cervical dysplasia, but results from previous studies were not consistent. Subjects and methods: In this hospital-based case-control study conducted in São Paulo city, Brazil, we evaluated the association of serum carotenoids (&#946;-carotene, lycopene), tocopherols (&#945;- and &#947;-), and dietary intakes with the risk of incident histologically confirmed cervical intraepithelial neoplasia (CIN) grades 1, 2, 3, and cervical cancer. The sample included 453 controls and four groups of cases (CIN1, n= 140; CIN2, n= 126; CIN3, n= 231; invasive cancer, n=108) recruited from two major public hospital-based clinics between 2003 and 2005. Results. Concentrations of serum lycopene were negatively associated with CIN1, CIN3 and cancer, with odds ratio (OR) (95% confidence interval) for the highest compared with the lowest tertile of 0.53 (0.27-1.00, p trend=0.05) for CIN1, 0.48 (0.22-1.04, p trend=0.05) for CIN2 and 0.18 (0.06-0.52, p trend= 0.002) for cervical cancer adjusted for confounding variables and HPV status. The adjusted OR for cancer of the highest versus the lowest tertile of serum &#946;-carotene was 0.36 (0.13-1.03, p trend= 0.04). Increasing concentrations of serum &#945;- and &#947;-tocopherols were associated with 50% decreasing risk of CIN3, for the women in the highest compared with the lowest quartile after adjusting for confounding variables and HPV. Increased dietary intakes of dark green and deep yellow vegetables and fruits were inversely associated with CIN3 among women in the highest compared to the lowest tertile (adjusted OR= 0.52, 95%CI = 0.27-1.00; p trend=0.05). Conclusion: These results support the evidence that high serum levels of antioxidants as well as dietary intakes may reduce the risk for CIN3 and invasive cancer in Brazilian women.

Page generated in 0.0936 seconds