Orientadores: Paulo Ademar Martins Leal, Antonio Carlos de Oliveira Ferraz / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-21T10:17:09Z (GMT). No. of bitstreams: 1 Souza_FrancianeColares_D.pdf: 2902759 bytes, checksum: 9132390d28bc3d61c99fb9c0a0385692 (MD5) Previous issue date: 2012 / Resumo: O manejo inadequado é um fatores que afetam a qualidade de produtos agrícolas, conduzindo a perdas devido aos danos mecânicos e o desenvolvimento microbiano, agravado pelo armazenamento inadequado. No caso do figo, devido à limitada proteção oferecida pela epiderme e presença do ostíolo, o beneficiamento utilizando água não é recomendado, trazendo em pauta ações capazes de promover a desinfecção superficial sem afetar a qualidade do produto. Dentre os métodos físicos mais promissores para conservação de frutas estão a refrigeração, radiação ultravioleta (UV-C) e atmosfera modificada. Por outro lado, a utilização de métodos combinados apresenta vantagens devido sua ação sinérgica e complementar. Neste sentido, acredita-se que o uso combinado de métodos físicos pode trazer benefícios para a conservação de figos, principalmente voltada para o mercado externo, auxiliando na manutenção da qualidade do produto e redução da carga microbiana. Este trabalho teve como objetivo avaliar o desempenho da combinação dos tratamentos de atmosfera modificada passiva, atmosfera enriquecida com 100% de CO2 e radiação UV-C na conservação do figo 'Roxo de Valinhos'. As principais etapas foram as seguintes: (1) isolamento dos fungos causadores de podridao em figos 'Roxo de Valinhos' e teste de patogenicidade, utilizando métodos de inoculação de deposição de suspensão de esporos na epiderme do figo, com e sem perfuração, e com deposição sobre papel filtro, avaliando-se a incidência e a severidade dos patógenos com cálculo do Índice de Doença (ID); (2) identificação do nível de tolerância do figo à exposição da radiação UV-C de 0,00 kJ.m-2; 0,70 kJ.m-2; 1,32 kJ.m-2; 2,64 kJ.m-2 e 4,00 kJ.m-2, armazenados à 10°C e 20°C, utilizando como parâmetro de qualidade a aparência visual; (3) avaliação do efeito da radiação UV-C no crescimento in vitro e in vivo dos fungos Rhizopus stolonifer, Lasiodiplodia theobromae e Alternaria alternata, utilizando-se valores de energia de radiação iguais a 0,00 kJ.m-2; 2,64 kJ.m-2; 4,00 kJ.m-2; 8,00 kJ.m-2 e 16,00 kJ.m-2 para os ensaios in vitro e iguais a 0,00 kJ.m-2; 0,70 kJ.m-2; 1,32 kJ.m-2 e 2,64 kJ.m-2 para os ensaios in vivo, a 10ºC e 20ºC; (4) avaliação de desempenho do filme de polipropileno (PP) com espessuras de 25'mi'm, 30'mi'm e 50'mi'm na manutenção da qualidade de figos, avaliada pelos parâmetros perda de massa (PM), sólidos solúveis (SS), acidez titulável (AT), aparência visual e redução da incidência de podridão; (5) avaliação do efeito de atmosfera com 100% de CO2 por 4h, 8h e 12h, à 10ºC e 20ºC, na manutenção da qualidade e diminuição da carga microbiana no figo, avaliada pelos índices PM, SS, AT e aparência visual e (6) combinação do filme de PP de 30'mi'm com radiação UV-C de 1,32 kJ.m-2 e com a exposição à atmosfera com 100% de CO2 durante 4h. Os resultados evidenciaram que a utilização isolada do filme de PP de 30'mi'm, radiação UV-C e exposição à 100% de CO2 mostrou-se eficiente na manutenção da qualidade das frutas, sobretudo quando se utiliza o armazenamento refrigerado. O uso combinado do filme de PP de 30'mi'm com atmosfera modificada com 100% de CO2, representa uma alternativa para o armazenamento do figo, mesmo quando não se utiliza refrigeração, em função da redução da carga microbiana e manutenção da qualidade / Abstract: The main factor affecting quality of agricultural products is the inadequate management, leading to considerable losses due to mechanical damage and fungal contamination, aggravated by improper storage. The fig vulnerability is amplified due to the presence of the ostiole, a peculiar fig orifice, acting as an open door to contamination. Since aqueous sanitization is not recomended, other methods should be searched to promote surface sanitization without affecting the quality of the product. Some promising methods are cooling, ultraviolet radiation (UV-C) and modified atmosphere. A combined method also has advantages because of their synergistic effect on inhibiting microbial growth, and thus maintaining the nutritional and visual qualities of the product. Moreover, the combined use of physical methods, to improve the fig shelf life, potentially can increase business opportunities, specially in the international market. The main objective of this work was to evaluate the performance of the combination of modified atmosphere and UV-C radiation on 'Roxo de Valinhos' fig conservation. To attain this general goal several intermediate steps were performed: (1) fungi rot identification and associated pathogenicity using inoculation by deposition on filter paper to evaluate disease incidence and contamination severity; (2) UV-C radiation fig tolerance identification using energy levels of 0,00 kJ.m-2; 0,70 kJ.m-2; 1,32 kJ.m-2; 2,64 kJ.m-2 and 4,00 kJ.m-2, followed by storage at 10ºC and 20ºC; (3) evaluation of the effect of UV-C radiation on Rhizopus stolonifer, Lasiodiplodia theobromae and Alternaria alternata fungi growth, for in vitro and in vivo tests, using energy irradiation of 0,00 kJ.m-2; 2,64 kJ.m-2; 4,00 kJ.m-2; 8,00 kJ.m-2 and 16,00 kJ.m-2 for the in vitro test, and 0,00 kJ.m-2; 0,70 kJ.m-2; 1,32 kJ.m-2 e 2,64 kJ.m-2 for the in vivo test, at 10ºC and 20ºC; (4) evaluation of the polypropylene (PP) in maintaining the quality, using film thicknesses of 25'mi'm, 30'mi'm and 50'mi'm; (5) evaluation of the fig exposition to 100% CO2 modified atmosphere for 4h, 8h and 12h, followed by storage at 10ºC and 20ºC, in maintaining quality and keeping the microbiological load low and (6) evaluation of the combined use of 30'mi'm PP film with UV-C irradiation of 1,32 kJ.m-2 and 100% CO2 modified atmosphere during 4h. Results have shown that the use of the 30'mi'm PP film, radiation UV-C of 1,32 kJ.m-2 and exposition to 100% of CO2 for 4h was effective in maintaining the quality of the fruits, specially when refrigerated storage is employed. It was concluded that combined use of the 30'mi'm PP film with high CO2 concentration represents an alternative to non refrigerated fig storage, due to the reduction of the microbial load / Doutorado / Tecnologia Pós-Colheita / Doutora em Engenharia Agrícola

Der Umgang mit ionisierender Strahlung in der medizinischen Diagnostik und Therapie ge-winnt ständig an Bedeutung. Welche Auswirkungen dabei geringe Dosen ionisierender Strahlung auf biologische Systeme haben, ist daher relevant und Gegenstand der Forschung. Die Adaptive Antwort kann in der Strahlenbiologie den Niedrig-Dosis-Effekten zugeordnet werden. Dieser Effekt, der auch als Präkonditionierung bezeichnet wird, beschreibt den protektiven Effekt, den eine niedrig dosierte Vorbestrahlung auf eine hoch dosierte Folgebestrahlung hat. Die Adaptive Antwort lässt sich beispielsweise durch Reduzierung von DNA-Schäden oder ein verbessertes Zellüberleben nachweisen. Die protektive Wirkung vor einer hohen Dosis tritt nur in einem begrenzten Zeitfenster zur Vorbestrahlung auf. In dieser Arbeit erfolgte der Nachweis der Adaptiven Antwort an Rattenschilddrüsenzellen, die über einen Natriumiodidsymporter (NIS) verfügen. Nach einer niedrig dosierten Vorbestrahlung und einem bestimmten Erholungsintervall erfolgte dazu jeweils eine zweite Bestrahlung mit einer therapeutisch wirksamen Dosis. Als biologischer Endpunkt wurde das klonogene Zellüberleben (Koloniebildungstest) gewählt. Die Bestrahlung erfolgte mit Röntgenstrahlung und 99mTc. Das 99mTc wird über den NIS in die Zellen aufgenommen. Diese intrazelluläre Radionuklidaufnahme kann durch Zugabe von Perchlorat fast vollständig blockiert werden. So konnte mit 99mTc sowohl ein intrazellulärer als auch ein extrazellulärer Bestrahlungsmodus realisiert werden. Durch die Untersuchung des Uptakes wurde jeweils das Ausmaß der intrazellulären Radionuklidaufnahme bestimmt. Ziel dieser Arbeit war es, die Adaptive Antwort durch Kombination und Variation der Bestrahlungssequenzen Rönt-genstrahlung, 99mTc und 99mTc mit Perchlorat nachzuweisen. Zur Einschätzung der Radiotoxizität wurden Dosis-Wirkungs-Kurven der Bestrahlungsmoda-litäten erstellt. Dabei konnten linear-quadratische bzw. lineare Dosis-Wirkungs-Beziehungen nachgewiesen werden. Die intrazelluläre Aufnahme von 99mTc führte im Vergleich zur extra-zellulären Bestrahlung durch Inkubation mit Perchlorat bei gleichen Aktivitätskonzentrationen zu stark verminderten Überlebensfraktionen. Die Ergebnisse wurden verwendet, um geeignete Dosisbereiche zum Nachweis der Adaptiven Antwort zu ermitteln. Die Adaptive Antwort wurde zunächst durch zweimalige Bestrahlung durch die gleiche Strah-lenqualität nachgewiesen. Für Röntgenstrahlung, 99mTc und 99mTc mit Perchlorat wurden je-weils die Vorbestrahlungsdosen von 0,01 Gy bis 0,75 Gy und die Erholungszeiten von 2 h bis 24 h untersucht. Nachbestrahlt wurde bei Röntgenstrahlung und 99mTc mit 2 Gy und bei 99mTc mit Perchloratinkubation mit 1 Gy. Der Nachweis eines höheren Zellüberlebens durch die Vorbestrahlung gelang bei allen drei Bestrahlungsmodalitäten. Die Adaptive Antwort war jeweils bei 0,025 Gy und 0,05 Gy Vorbestrahlungsdosis und nach 6 h Erholungszeit am stärksten ausgeprägt. Nach 10 h war jeweils keine protektive Wirkung nach Vorbestrahlung mehr nachweisbar. Im Folgenden wurden die Bestrahlungsmodalitäten untereinander variiert. So wurde Rönt-genstrahlung mit 99mTc, sowie Röntgenstrahlung mit 99mTc und Perchlorat kombiniert und die Sequenzen jeweils variiert. Als Vorbestrahlungsdosen wurden 0,025 Gy und 0,05 Gy gewählt. Die Zeitfenster zwischen Vor- und Nachbestrahlung betrugen 4 h; 6 h und 24 h. Bei allen 4 Kombinationen konnte nach 6 h Erholungszeit eine Adaptive Antwort nachgewiesen werden. Die größte protektive Wirkung konnte in allen Versuchen durch 0,05 Gy Vorbestrahlung erreicht werden. Entsprechend der Zielsetzung konnte in dieser Arbeit die Adaptive Antwort unabhängig von der Bestrahlungsmodalität und deren Sequenz bei Vor- und Nachbestrahlung nachgewiesen werden. Insbesondere gelangen der Vergleich und die Kombination aus extra- und intrazellu-lärer Bestrahlung. Es konnte bestätigt werden, dass der durch die Vorbehandlung induzierte protektive Effekt nur in einem begrenzten Zeitfenster bestehen bleibt. Des Weiteren zeichnete sich eine Abhängigkeit des Ausmaßes der Adaptiven Antwort von der Vorbestrahlungsdosis ab. Die Ergebnisse bestätigen die aktuell anerkannte Hypothese, die die Adaptive Antwort als Teil einer allgemeinen Stressantwort der Zelle auf verschiedene Noxen sieht (Calabrese, et al., 2007). Im Hinblick auf moderne Therapieansätze in der Onkologie, wie CIERT oder der Radiorezeptortherapie, ist der Einfluss der Niedrig-Dosis-Effekte, wie der Adaptiven Antwort, auf das Behandlungsergebnis jedoch eher vernachlässigbar. Die angewandte Induktionsdosis sowohl durch eine Röntgenuntersuchung als auch durch eine Szintigraphie ist zu gering bzw. bei der fraktionierten Strahlentherapie zu hoch, um eine Adaptive Antwort zu induzieren. Weiterhin ist das Zeitfenster für die Ausbildung der Protektion in der Praxis nicht gegeben.

The general public is at risk of ionising-radiation exposure. The development of high-throughput methods to triage exposures is warranted. Current biodosimetry techniques are low-throughput and encumbered by time and technical expertise. Although there has been an emergence of gene-profiling tools for the purpose of photon biodosimetry, similar capacities do not exist for alpha-particle radiation. Herein is the first genomic study useful for alpha-particle radiation biodosimetric triage. This work has identified robust alpha-particle induced gene-based biomarkers in isolated, ex-vivo irradiated leukocytes from multiple donors. It was found that alpha-particle and photon radiation elicited similar transcriptional responses, which could potentially be distinguished by aggregate-signature analysis. Although no distinct genes were sole indicators of exposure type, clustering algorithms and principal component analysis were able to demarcate radiation type with some success. By comparing the biological effects elicited by photon and alpha-particle radiation, significant contributions have been made to the field of radiation biodosimetry.

Toxoplasma gondii é um agente disseminado com um ciclo de vida complexo que envolve gatos e hospedeiros de sangue quente, incluindo o homem. Componentes vacinais são imunógenos pobres e vacinas atenuadas causam doenças crônicas. Taquizoítos irradiados à 255Gy induzem uma imunidade similar a infecção, com proteção parcial, sem estudos sobre memória. Estudamos a produção de IgG in vitro por células do baço e medula óssea de camundongos imunizados com taquizoítos irradiados e infectados. A medula óssea contém um número maior de células específicas do que o baço. As células de memória são de alta afinidade, mas IgG sérica apresentaram baixa avidez. Há também anticorpos específicos IgA nas fezes. Todas as vacinas indutoras de proteção parcial contra o desafio, que foi mais evidente em alta patogenicidade da cepa ME-49. A proteção foi proporcional tanto à quantidade de anticorpos IgG no soro ou produzidos por células da medula óssea. Nossos dados mostram claramente que os anticorpos de alta afinidade estão relacionados com a sobrevida específica de memória celular. / Toxoplasma gondii is a disseminated agent with a complex life cycle involving cats and warm blood hosts, including man. Component vaccines are poor immunogens and attenuated vaccines cause chronic disease. 255Gy irradiated tachyzoites induce the same immunity as natural infection, with partial protection, without studies on immunological memory. We studied in vitro production of specific IgG by spleen and bone marrow cells of mice immunized with irradiated tachyzoites, comparing with chronically infected animals. Bone marrow contains larger numbers of specific cells than spleen. Memory cells were of high affinity, but serum presented low avidity IgG. We also show presence of specific IgA antibodies in stools. All immunizations induce partial protection against challenge, which was more evident in highly pathogenic ME-49 strain. The protection was proportional both to the amount of IgG antibodies in serum or produced by bone marrow cells. Our data clearly shows that high affinity antibodies are related to specific memory cell survival.

Made available in DSpace on 2016-05-02T13:55:20Z (GMT). No. of bitstreams: 1 Ariadne Mendes da Silva-dissertacao.pdf: 132109 bytes, checksum: db3c6f5e1f96d9b1c58c741db945d3b0 (MD5) Previous issue date: 2012-12-20 / Brazil uses irradiation in spices and condiments to marketing, particularly chicken meat is another national product with enormous potential for the use of irradiation. In this context, the objective of this research was to verify the effectiveness of the levels of gamma radiation on the qualitative characteristics of breast meat of broilers and vacuum packed in conventional packaging. Adopted for the experiment was a completely randomized design (2x4), two packs (vacuum and conventional) and four concentrations of irradiation (0, 2, 4, 8KGy) for a total of 8 treatments (T1-Vacuum packing + 0Gy , T2-Vacuum packing + 2 Gy, T3-Vacuum packing 4GY +, T4-Vacuum packing + 8GY, T5-Packaging + 0Gy conventional, conventional T6-Pack + 2 Gy, conventional T7-Packaging + 4GY and conventional T8-Packaging 8GY +), with five replications in which the samples were evaluated in three storage times (0, 7 and 14 days), totaling 120 samples. No significant effect (p> 0.05) packaging and irradiation on meat chicken breast on drip loss, pH and water holding capacity and negative for salmonella and coliforms was observed. It was observed effect (p <0.05) absorption capacity after seven days storage and drip loss after 14 days storage. The irradiation and vacuum packaging are effective after 14 days of storage, since the loss of exudate were not the most balanced with excess nor the lower drip loss. Results obtained in this study may indicate the least amount irradiation and vacuum packaging for longer storage times. The results were analyzed by means of variance (ANOVA) and Tukey's test at 5% probability, where the results were subjected to statistical program SAS. / O Brasil utiliza a irradiação em especiarias e condimentos para a comercialização, a carne de frango é particularmente outro produto nacional com enorme potencial para o emprego da irradiação. Neste contexto, o objetivo desta pesquisa foi verificar a eficácia dos níveis de radiação gama sobre as características qualitativas da carne de peito de frangos de corte embalados a vácuo e em embalagem convencional. Para o experimento adotou-se um delineamento inteiramente ao acaso (2x4), duas embalagens (vácuo e convencional) e quatro concentrações de irradiações (0, 2, 4, 8KGy) perfazendo um total de 8 tratamentos (T1-Embalagem a vácuo + 0Gy, T2- Embalagem a vácuo + 2Gy , T3 -Embalagem a vácuo + 4Gy, T4-Embalagem a vácuo + 8Gy, T5- Embalagem convencional + 0Gy, T6- Embalagem convencional + 2Gy, T7- Embalagem convencional + 4Gy e T8- Embalagem convencional + 8Gy), com cinco repetições em que as amostras foram avaliadas em três tempos de armazenamento( 0, 7 e 14 dias), totalizando de 120 amostras. Não se observou efeito significativo (p>0,05) da embalagem e da irradiação na carne de peito de frango sobre a perda por exsudação, pH e capacidade de retenção de água e negativo para salmonella e coliformes. Observou-se efeito (p<0,05) para capacidade de absorção aos sete dias após o armazenamento e perda por exsudação aos 14 dias após armazenamento. A irradiação e embalagem a vácuo são efetivas após 14 dias de armazenamento, pois as perdas de exsudação foram as mais equilibradas não tendo excesso e nem a menor perda por exsudação. Diante dos resultados obtidos neste estudo, pode-se indicar a menor quantidade irradiação e embalagem á vácuo para tempos mais prolongados de armazenamento. Os resultados foram analisados por meio de Variância (ANOVA) e teste de médias de Tukey a 5% de probabilidade, onde, os resultados foram submetidos ao programa estatístico do SAS.

O desenvolvimento da tecnologia de telecomunicação móvel ensejou a implantação massiva de ERBs (Estações rádio base) para o atendimento da crescente demanda ocorrida na última década. As ERBs, por sua vez, constituem fontes emissoras de radiação não ionizante. Os estudos científicos concluídos nos últimos anos indicam que a exposição à radiação não ionizante, principalmente em longo prazo, pode produzir consequências negativas para a saúde humana, por essa razão, mister se faz a aplicação do Princípio da Precaução que vem evocar cautela diante do risco. Das principais normas existentes no planeta, nem todas adotaram o princípio da precaução ao fixar seus limites; em decorrência, a maioria das normas que determinam limites máximos de exposição teve como base apenas os efeitos biológicos danosos da exposição à radiação não ionizante já conhecidos pela comunidade científica e relacionados à exposição aguda. Dessa maneira, diante do risco resultante da exposição, surge outra questão de grande importância o gerenciamento dessas ERBs. Haveria, na cidade de São Paulo, um sistema de gerenciamento das ERBs que garanta o cumprimento dos limites e padrões definidos na legislação local? Nesse cenário, este estudo pretende: (i) elaborar um levantamento junto aos três órgãos públicos responsáveis pelo gerenciamento das ERBs na cidade de São Paulo, sobre o atual estágio dos sistemas de gerenciamento praticado por cada entidade pública legalmente competente para o respectivo exercício; (ii) desenvolver uma análise das características básicas dos sistemas de gerenciamento das ERBs no município de São Paulo, estudando a evolução ocorrida entre os anos de 2006 e 2011; e, (iii) avaliar as possibilidades de melhoria na proposta atual de gerenciamento das ERBs, no município de São Paulo. Esta pesquisa parte dos dados levantados no ano de 2006, na cidade de São Paulo, que na ocasião indicaram a existência de um sistema de gerenciamento das ERBs incipiente e frágil por parte dos órgãos públicos competentes (Secretaria Estadual da Saúde, Secretaria Municipal do Verde e Meio Ambiente e ANATEL). A partir deste cenário, elabora-se uma análise das características básicas dos sistemas de gerenciamento das ERBs no município de São Paulo, estudando a evolução ocorrida entre os anos de 2006 e 2011. Dessa avaliação, são identificadas falhas e possibilidades de melhoria nos sistemas de gerenciamento das ERBs praticados no município de São Paulo na atualidade. A metodologia adotada constitui-se de pesquisa de campo, por meio de entrevista estruturada, aplicada aos representantes dos órgãos públicos responsáveis pelo gerenciamento das ERBs no município de São Paulo. Finalmente, é desenvolvida a interpretação dos dados, global e individualmente, de forma que os resultados obtidos possibilitaram as considerações e propostas formuladas no capítulo conclusivo desta pesquisa. / The development of mobile telecommunication technology gave rise to the massive deployment of RBSs (Radio base stations) to attend the growing demand occurred in the last decade. The RBSs in turn, are emitting sources of non-ionizing radiation. Scientific studies concluded in the recent years indicate that exposure to non-ionizing radiation, especially in the long term, can produce negative consequences for human health, therefore, it becomes important to apply the Precautionary Principle that evokes caution in risk situation. Of the main rules in the world, not all adopted the precautionary principle in setting its limits; as a result, most of the rules that determine maximum exposure limits were based only on the harmful biological effects of exposure to ionizing radiation already known by the scientific community and related to acute exposure exclusively. Thus, with the risk resulting from exposure, there is another major issue - the management of these RBSs. Would it exist, in São Paulo city, a management system of RBSs to ensure compliance with the limits and standards defined by local law? In this scenario, this study aims to: (i) develop a survey along the three entities responsible for managing the RBSs in São Paulo, on the current stage of respective management systems practiced by each public entity legally responsible for the exercise thereof; (ii) develop an analysis of the basic features of the RBSs management systems in São Paulo, studying the evolution that occurred between the years 2006 and 2011; and, (iii) assess the possibilities for improvement in the current proposal for the RBSs management in São Paulo. This survey starts from the data collected in 2006, in São Paulo, which at the time indicated the existence of an incipient and fragile RBSs management system, by the public agencies (Secretaria Estadual da Saúde, Secretaria Municipal do Verde e Meio Ambiente e Anatel). From this scenario, it is drawn up an analysis of the basic features of the RBSs management systems in São Paulo, studying the evolution that occurred between the years 2006 and 2011. From this evaluation, are identified gaps and opportunities for improving the RBSs management systems practiced in São Paulo at present. The methodology consisted of field survey through structured questionnaires, applied to representatives of public agencies responsible for RBSs management in São Paulo. Finally, it is developed the interpretation of the data, overall and individually, so that the results enabled the considerations and proposals made in the concluding chapter of this research.

A ce jour, l’évaluation des risques associés à l’incorporation de radionucléides et l’élaboration des normes de radioprotection en résultant sont principalement basées sur les résultats du suivi épidémiologique de populations exposées aux rayonnements ionisants par voie externe. Les analogies et extrapolations employées dans cette démarche sont entourées d’incertitudes. Afin de pouvoir évaluer la validité des hypothèses retenues dans ce cadre par la Commission Internationale de Protection Radiologique, il est nécessaire de réaliser de nouvelles études épidémiologiques au sein de populations exposées à des émetteurs internes. C’est notamment le cas pour ce qui concerne les expositions à l’uranium, dont les effets sanitaires potentiels demeurent mal caractérisés. Par ailleurs, alors que les effets cancérigènes des radiations ionisantes sont établis et de mieux en mieux caractérisés, l’hypothèse d’un effet de faibles doses de rayonnements ionisants sur le développement de maladies de l’appareil circulatoire a été émise récemment, et demande à être évaluée de manière approfondie.L’objectif de cette thèse est de contribuer à améliorer la connaissance des effets sanitaires des expositions chroniques à de faibles doses de rayonnements ionisants, en particulier du fait de contamination internes par l’uranium, en support à l’évaluation et si nécessaire à la consolidation des normes internationales de radioprotection.La thèse s’articule autour de trois axes:- L’analyse de la mortalité dans une cohorte de 1300 travailleurs d’usines de traitement du minerai d’uranium (F-MILLERS), par comparaison avec la mortalité de la population générale française par calcul de rapports de mortalité standardisés.- L’analyse de l’association entre la dose (interne et externe) et la mortalité par cancers et maladies cardiovasculaires dans une cohorte de 4000 travailleurs de l’uranium: Analyse statistique classique (fréquentiste) incluant une exploration détaillée de l’impact de potentiels facteurs confondants individuels rarement disponibles dans d’autres cohortes de travailleurs du nucléaire (ex: obésité, tabagisme, tension artérielle).- Le développement d’une approche hiérarchique bayésienne permettant de tenir compte des incertitudes engendrées par l’estimation de la dose interne à partir de mesures radiotoxicologiques fortement censurées à gauche (i.e., inférieures à un seuil) dans l’estimation de risques sanitaires radio-induits, basée sur cette dose. / Nowadays, the assessment of the risks associated with the incorporation of radionuclides and the resulting development of radiological protection standards are mainly based on the results of the epidemiological monitoring of populations exposed to external ionizing radiation. The analogies and extrapolations used in this process are surrounded by uncertainties. In order to be able to evaluate the validity of the assumptions adopted in this context by the International Commission on Radiological Protection (ICRP), it is necessary to conduct new epidemiological studies in populations exposed to internal emitters. This is particularly the case for uranium exposures, whose potential health effects remain poorly characterized. Moreover, while the carcinogenic effects of ionizing radiation are established and increasingly well characterized, the hypothesis of an effect of low doses of ionizing radiation on the development of diseases of the circulatory system has been suggested recently, and requires to be evaluated thoroughly.The aim of this PhD thesis project is to improve the knowledge of the health effects of chronic internal exposure to low doses of ionizing radiation, particularly due to internal contamination by uranium, in support of the evaluation and if necessary to the consolidation of international radiation protection standards.The PhD thesis project includes three axes:- Analysis of mortality in a new cohort of 1,300 workers employed by uranium-milling companies, by comparison with the mortality of general French population by computing standardized mortality ratios.- Analysis of the association between dose (internal and external) and mortality from cancer and cardiovascular diseases in a cohort of 4,000 uranium workers: classical statistical analysis (frequentist) included detailed exploration of the impact of potential confounding factors rarely available in other cohorts of nuclear workers (e.g.: obesity, smoking, blood pressure)- Development of a Bayesian hierarchical approach allowing to account for uncertainties induced by the estimation of internal dose from radiotoxicological measurement that are strongly left-censored (i.e., lower than a threshold) in radiation-induced risk estimates, based on this dose.

Tissue regeneration is a complex and highly orchestrated process dependent on cells with the potential to restore structures and functions and on controlling factors from the tissue microenvironment. Hematopoietic tissue has a high ability to regenerate, which is attributed to the presence of stem cells, but the regeneration of severely damaged adult tissue is still only partially understood. Hematopoietic tissue provides a unique opportunity to study tissue regeneration due to its well-established steady- state structure and function, easy accessibility, advanced research methods, and well-defined embryonic, fetal, and adult stages of development. Embryonic/fetal liver hematopoiesis and adult hematopoiesis recovering from damage share the needto expand populations of progenitors and stem cells in parallel with increasing production of mature blood cells. We analyzed adult hematopoiesis in mice subjected to a submyeloablative dose (6 Gy) of gamma radiation, in which only a few cells with reconstituting capacity survived. We targeted the period of regeneration characterized by the renewed massive production of mature blood cells and the ongoing expansion of immature hematopoietic cells. Cells from the top of the hematopoietic hierarchy, hematopoietic stem cells, and multipotent progenitors are almost missing...

This thesis deals with the problem of shielding ionizing radiation which is a beam that has enough energy to ionize an atom or a molecule of an irradiated substance. This radiation can occur in nuclear facilities such as a nuclear power plant, a particle accelerator, or in X-rays in healthcare. Until now, standard shielding materials, most often lead or concrete, have been used to protect against ionizing radiation. New trends are therefore trying to replace these materials with lighter, more effective and harmless materials. The practical part is focused on measure the data to obtain the basic properties of shielding materials, such as the attenuation factor and the buildup factor. A measuring platform is described here, which can be used to measure the data needed to calculate the attenuation factor and the buildup factor. The measurement results are compared with tabular values to determine the accuracy of the measurements. Furthermore, the results of measurements of five concrete materials from the company MICo, spol. s r.o. To obtain theoretical values, the simulation program MCNP6 was used, in which it is possible to create a model of the measuring platform, which was used in practical measurements. Next the shielding material, source and detector are defined. The result lead again to the data needed to determine the attenuation factor. The results of measurement and simulation data in MCNP6 are evaluated and graphically processed into such a form that it is possible to compare the properties of shielding materials with each other.

The thesis is focused on gathering of theoretical backgrounds for geomagnetic measurements, measurement of electromagnetic and radiometric quantities in a natural locality, and subsequent evaluation of the obtained results from the point of view of their interrelations and in the context of hygienic regulations. All the theoretical backgrounds of each field are assigned to the measurement methodology and appropriate measuring technique, selected according to information from available sources. Appropriate instruments, landscape location, measurements were made, the results were evaluated and interpreted. The result is graphical output in the QGIS geographic information system.