Reactivity of human fetal and adult immortalized hepatocytes to potentially toxic bilirubin and bile acid species

Dissertação apresentada para a obtenção do Grau de Mestre em Genética Molecular e Biomedicina, pela Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia

Wetland Habitat Studies using various Classification Techniques on Multi-Spectral Landsat Imagery: Case study: Tram chim National Park, Dong Thap Vietnam

Dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Science in Geospatial Technologies

Exposição a fungos dos trabalhadores dos ginásios com piscina

RESUMO - Os trabalhadores dos ginásios com piscinas apresentam maior prevalência de lesões fúngicas, como a Tinea pedis e a onicomicose, devido às características intrínsecas da sua actividade profissional, pois apresentam mais horas por dia de exposição à contaminação fúngica das superfícies. Esta situação verifica-se não só por serem os que mais frequentam os locais possíveis de estarem contaminados, como é o caso de balneários, vestiários e zona envolvente às piscinas, mas também porque algumas das actividades desenvolvidas são realizadas com os pés descalços. Além disso, a utilização de roupa sintética e de calçado ocluso, que retêm a sudação excessiva, favorece o desenvolvimento fúngico. Constituiu objectivo deste trabalho conhecer o risco de infecção e/ou lesão (Tinea pedis e onicomicose) nos trabalhadores dos ginásios com piscina e a sua eventual relação com a exposição à contaminação fúngica (ar e superfícies) dos locais de trabalho. Foram descritas as variáveis ambientais e biológicas que influenciam a infecção e/ou lesão fúngica em ambiente profissional e exploradas eventuais associações entre essas mesmas variáveis. Foram também conhecidas as diferenças da contaminação fúngica das superfícies entre as duas principais estações do ano (Verão e Inverno) e entre antes e depois da lavagem e desinfecção. O estudo realizado possui uma componente transversal, em que se pretendeu descrever os fenómenos ambientais e biológicos da contaminação fúngica em ambiente profissional e explorar eventuais associações entre variáveis; uma componente longitudinal, em que foram conhecidas as diferenças sazonais da contaminação fúngica das superfícies; e, ainda, uma componente quase experimental, em que foi analisada a distribuição fúngica nas superfícies antes e depois da lavagem e desinfecção. Na vertente transversal foi considerada uma amostra de 10 ginásios com piscina e outra amostra de, pelo menos, 10 profissionais de cada estabelecimento, perfazendo um total de 124 trabalhadores (75 Homens - 60,48% e 49 Mulheres - 39,52%). Foram realizadas 258 colheitas biológicas aos pés dos trabalhadores, efectuada a avaliação ambiental da contaminação fúngica dos estabelecimentos através de 50 colheitas de amostras de ar e 120 colheitas de amostras de superfícies (60 antes e 60 depois da lavagem e desinfecção) e efectuados os respectivos processamento laboratorial e identificação fúngica. Foram também avaliadas as variáveis ambientais temperatura, humidade relativa e velocidade do ar, preenchidas 10 grelhas de observação, com o objectivo de efectuar o registo de informação sobre as variáveis que xx influenciam a exposição ocupacional às espécies fúngicas e, ainda, completadas 124 grelhas de observação inerentes à colheita de material biológico, de modo a realizar o registo dos profissionais com lesão e outras informações pertinentes para a análise laboratorial. Todos os 124 trabalhadores responderam a um questionário, em simultâneo à realização das colheitas biológicas, de modo a conhecer algumas das variáveis individuais e profissionais com pertinência para o presente estudo. Num dos estabelecimentos, foram também estudadas as diferenças da contaminação fúngica das superfícies entre antes e depois da lavagem e desinfecção e, ainda, entre as duas estações do ano (Verão e Inverno). Nesse estabelecimento, foram realizadas 36 colheitas de superfícies antes e 36 colheitas depois da lavagem e desinfecção, em 6 dias diferentes da semana, durante 6 semanas sequenciais em cada estação do ano, completando um total de 72 colheitas de superfícies. Foi ainda criado e aplicado um método para estabelecer um padrão de exposição profissional a fungos nas superfícies, de modo a permitir definir níveis semi-quantitativos de estimação do risco de infecção fúngica dos trabalhadores dos ginásios com piscinas. Para o critério da Gravidade, considerou-se que a gravidade da contaminação e, consequentemente, da possível lesão, está intimamente relacionada com a espécie fúngica envolvida. Foram calculadas as médias da contaminação fúngica por cada estabelecimento antes da lavagem e desinfecção, de modo a estabelecer os níveis de Frequência e, em relação à Exposição, foram estabelecidos intervalos para agrupar as horas semanais de trabalho. Dos 124 trabalhadores que participaram no estudo, 58 (46,8%) possuíam lesões visíveis. Nesses 58, as Leveduras foram as mais isoladas (41,4%), seguidas dos Dermatófitos (24,1%) e de Fungos Filamentosos Não Dermatófitos (6,9%). Candida parapsilosis e Rhodotorula sp. foram as Leveduras mais frequentemente isoladas (20,2%); no caso dos Dermatófitos, Trichophyton rubrum foi a espécie mais frequente (55,5%) e, relativamente aos Fungos Filamentosos Não Dermatófitos, Penicillium sp. foi o mais isolado (15,6%), seguido do género Fusarium (12,5%). No que concerne à contaminação fúngica das superfícies, 37 fungos filamentosos foram isolados. Fusarium foi o género mais frequente, antes e depois da lavagem e desinfecção (19,1% - 17,2%). Em relação aos fungos leveduriformes, 12 leveduras diferentes foram identificadas, tendo sido os géneros Cryptococcus (40,6%) e Candida (49,3%) os mais frequentes antes e depois da lavagem e desinfecção, respectivamente. Em relação à contaminação fúngica do ar, foram identificados 25 fungos filamentosos diferentes, em que os 3 géneros mais frequentemente isolados foram Cladosporium (36,6%), Penicillium (19,0%) e Aspergillus (10,2%). Relativamente às leveduras, foi identificado o género xxi Rhodotorula (87,5%) e as espécies Trichosporon mucoides e Cryptococcus unigutulattus (12,5%). Verificou-se associação, ao nível de significância de 5%, entre lesão visível e horas semanais e entre lesão visível e tempo de profissão, comprovando a influência da duração da exposição ao factor de risco (contaminação fúngica do ambiente profissional), para a presença de lesão visível nos trabalhadores expostos (Tinea pedis e onicomicose), ficando demonstrada a relação entre a exposição ao factor de risco em estudo – exposição profissional a fungos – com os efeitos para a saúde. As variáveis ambientais avaliadas (temperatura, humidade relativa e velocidade do ar) não influenciaram a contaminação fúngica do ar e das superfícies, não tendo sido evidenciada nenhuma relação estatisticamente significativa (p>0,05). Contudo, verificou-se influência do número de ocupantes que frequentaram cada um dos estabelecimentos nas médias das unidades formadoras de colónias por metro quadrado nas superfícies antes da lavagem e desinfecção. Não se verificou correlação entre os resultados quantitativos da contaminação fúngica do ar e a das superfícies dos 10 estabelecimentos monitorizados. No entanto, verificaram-se diferenças significativas, ao nível de significância de 10%, entre a contaminação fúngica das superfícies e a contaminação fúngica do ar (p<0,1), tendo-se constatado que apesar de 50% dos valores mais baixos terem sido superiores na contaminação fúngica do ar, a contaminação fúngica das superfícies apresentou-se com maior variabilidade quantitativa. Em relação às diferenças significativas na contaminação fúngica das superfícies nos 10 estabelecimentos entre antes e depois da lavagem e desinfecção, apenas se verificou redução significativa (p<0,05) da contaminação fúngica depois da lavagem e desinfecção nos balneários e vestiários masculinos em relação aos fungos leveduriformes. No estabelecimento seleccionado, verificou-se que a relação entre a contaminação fúngica e a temperatura e humidade relativa não foi significativa (p>0,05) em ambas as estações do ano e também não se constatou influência dos ocupantes nos valores médios das unidades formadoras de colónias por metro quadrado das superfícies antes da lavagem e desinfecção em ambas as estações de ano. Em quase todas as situações em que se verificaram diferenças significativas entre as duas estações do ano, verificou-se um aumento das unidades formadoras de colónias por metro quadrado no Inverno, com excepção do total das unidades formadoras de colónias por metro quadrado antes da lavagem e desinfecção nos balneários e vestiários masculinos em que se verificou aumento no Verão. Constatou-se também que apenas ocorreu redução da xxii contaminação fúngica depois da lavagem e desinfecção nas escadas de acesso no Inverno e nos balneários e vestiários masculinos no Verão. Com a aplicação do método para estabelecer um padrão de exposição profissional a fungos nas superfícies obteve-se, nos 10 estabelecimentos, com Nível de Risco Mínimo 65 locais (54,2%), com Nível de Risco Médio 23 locais (19,2%) e com Nível de Risco Elevado 32 locais (26,6%). Próximo do jacuzzi e junto ao tanque foram os locais com mais classificações de Nível de Risco Elevado. No estabelecimento seleccionado verificou-se que, no Verão, depois da lavagem e desinfecção, ocorreu um maior número de locais classificados no Nível de Risco Elevado e, no Inverno, constatou-se a situação inversa, tendo sido observado maior número de locais com Nível de Risco Elevado antes da lavagem e desinfecção. Junto ao tanque e nas escadas de acesso à zona envolvente ao jacuzzi e tanque foram os locais com mais classificações de Nível de Risco Elevado, no Verão e no Inverno. Foram isolados nas superfícies fungos comuns aos isolados nos trabalhadores. Antes da lavagem e desinfecção, 30,3% dos fungos foram isolados nas superfícies e nos trabalhadores e depois desses procedimentos 45,5% dos fungos foram também isolados comummente. As Leveduras foram as mais isoladas comummente e as que se verificaram mais frequentes antes e depois da lavagem e desinfecção da superfícies e, também, nos resultados das colheitas biológicas realizadas aos trabalhadores, foram o género Rhodotorula e a espécie Candida parapsilosis, permitindo confirmar que a infecção fúngica dos trabalhadores está relacionada com a contaminação fúngica das superfícies. Concluiu-se que é necessária a intervenção em Saúde Ocupacional no âmbito da vigilância ambiental e da vigilância da saúde, com o intuito de diminuir a prevalência das infecções fúngicas. Para a prossecução desse objectivo, sugere-se a implementação de medidas preventivas, nomeadamente: o controlo da contaminação fúngica das superfícies mediante procedimentos de lavagem e desinfecção eficazes, de modo a minimizar a contaminação fúngica das superfícies; a identificação precoce da infecção através da realização de colheitas biológicas periódicas aos trabalhadores, inseridas num protocolo de vigilância da saúde; e, ainda, a sensibilização para a aplicação de medidas de higiene pessoal e o tratamento das patologias. A aplicação do método criado para estabelecer um padrão de exposição profissional a fungos nas superfícies servirá não só para a estimação do risco de infecção fúngica dos trabalhadores de ginásios com piscinas, mas também para facilitar o estabelecimento de valores fúngicos de referência, a implementação de medidas correctivas adequadas e imediatas e, ainda, a prevenção de infecções fúngicas, não só nos ginásios com piscina, mas também noutros contextos profissionais. ------------ SUMMARY - Gyms with swimming pools workers have higher prevalence of fungal injuries, such as Tinea pedis and onychomycosis. This is due to their work intrinsic characteristics, since they have more hours per day of exposure to surfaces fungal contamination. This occurs not only because they attend sites most likely to be contaminated, such as showers, changing rooms and pool surrounding area, but also because some of the activities are done barefoot. Furthermore, synthetic clothing and occluded footwear use, which retain the excessive sweating, promotes fungal development. The aim of this study was to know gymnasiums with swimming pool workers infection and/or injury (Tinea pedis and onychomycosis) risk, and its possible relationship with exposure to workplace fungal contamination (air and surfaces). This study describes environmental and biological variables that influence infection and/or fungal injury in a professional setting and explored possible associations between these variables. Differences in surfaces fungal contamination between the two main seasons (summer and winter), as well between before and after cleaning and disinfection were known. It was developed a study with an cross-sectional perspective, that aimed to describe the biological and environmental phenomena of fungal contamination in a professional environment and explore possible associations between variables; an longitudinal perspective in which were known surfaces fungal contamination seasonal differences; and also with an almost experimental perspective that analyzed surfaces fungal distribution before and after cleaning and disinfection. The cross-sectional perspective comprised 10 gyms with swimming pool sample, and another sample of, at least, 10 professionals in each establishment totalling 124 workers (75 men – 60,48%, and 49 women – 39,52%). Were performed 258 biological samples at workers feet, environmental fungal contamination evaluation from the establishments through 50 air samples and 120 surfaces samples (60 before and 60 after cleaning and disinfection) and conducted their laboratory processing and fungal identification. Were also evaluated environmental variables, such as temperature, relative humidity and air velocity completed 10 observation grids, in order to obtain data about variables that affect occupational exposure to fungal species, and also completed 124 observation grids inherent to biological material collection, in order to know the professionals with injury and other relevant information for laboratory analysis. All 124 workers answered to a questionnaire at the same time that occur biological samples collection, in order to xxv obtain information about some of the individual and professional variables with relevance to this study. In one of the establishments were also studied differences concerning surfaces fungal contamination between before and after cleaning and disinfection, and also between two main seasons (summer and winter). In this setting, there were performed 36 surfaces samples before and 36 surfaces samples after cleaning and disinfection on 6 different week days for 6 sequential weeks in each season, totalling 72 surfaces samples. It was also created and implemented a method to establish a pattern for surfaces fungal occupational exposure, in order to help define semi-quantitative levels estimation to fungal infection risk in gyms with swimming pools workers. For Gravity criterion it was considered that contamination severity and, thus, the possible injury are closely related to implicate fungal species. Was calculated fungal contamination average by each establishment prior cleaning and disinfection, in order to establish Frequency levels. Regarding Exposure, were established weekly hours group intervals spent in professional activity. From the 124 professionals tested, 58 (46,8%) had visible injuries. In the 58 workers, Yeasts were the most isolated (41,4%), followed by Dermatophytes (24,1%) and Other Filamentous Fungi Besides Dermatophytes (6,9%). Candida parapsilosis and Rhodotorula sp. were the most frequently isolated Yeasts (20,2% for each), from Dermatophytes, Trichophyton rubrum was the most frequently isolated species (55,5%) and from Other Filamentous Fungi Besides Dermatophytes, Penicillium sp. was the most frequent (15,6%), followed by Fusarium genera (12,5%). Regarding surfaces fungal contamination, 37 filamentous fungi were isolated. Fusarium genera was the most frequent, before and after cleaning and disinfection (19,1% - 17,2%). Considering yeasts, 12 different yeasts were identified, being Cryptococcus (40,6%) and Candida (49,3%) genera the more frequent before and after cleaning and disinfection, respectively. In relation to air fungal contamination, 25 different filamentous fungi were identified and the 3 most frequently isolated genera were Cladosporium (36,6%), Penicillium (19,0%) and Aspergillus (10,2%). For yeasts, were identified Rhodotorula genera (87,5%), and also the species Trichosporon mucoides and Cryptococcus unigutulattus (12,5%). Was found association with 5% significance level, between visible injury and weekly hours and between visible injury and occupation time, confirming exposure duration influence to risk factor (work environment fungal contamination) for the visible injury presence in exposed workers (Tinea pedis and onychomycosis), being confirmed the relation between the study exposure risk - occupational exposure to fungi - with health effects. xxvi Environmental variables evaluated (temperature, relative humidity and air velocity) did not affect air and surfaces fungal contamination and wasn’t found no statistically significant relation (p>0,05). However, there was evidence that occupant’s number influence surfaces colony forming units mean per square meter before cleaning and disinfection. There was no correlation between quantitative data from air fungal contamination and surfaces fungal contamination from the 10 establishments monitored. However, there were significant differences with 10% significance level, between surfaces and air fungal contamination (p<0,1), and despite 50% of the lowest rates were higher in air fungal contamination, it was found that surfaces fungal contamination had more quantitative variability. Regarding differences from the 10 establishments surfaces fungal contamination, between before and after cleaning and disinfection, there was only a significant reduction (p<0,05) in fungal contamination after cleaning and disinfection in male changing rooms for yeasts. In the selected establishment, it was found that relation between fungal contamination and temperature and relative humidity was not significant (p>0,05) in both seasons, and also there wasn’t no influence observed from occupants in surfaces colony forming units mean per square meters before cleaning and disinfection in both seasons. In almost all situations where significant differences between the two seasons were shown, there was a colony-forming units per square meter increase in winter. There was an exception in total colony forming units per square meter before cleaning and disinfection in male changing room’s exception, where there was an increase in summer. Furthermore, was found that only occur a reduction in fungal contamination after cleaning and disinfection, on access stairs in winter, as well as in male changing rooms in summer. With application from the method to establish pattern for surfaces fungal occupational exposure, it was obtained, in the 10 establishments, 65 sites with Low Risk Level (54,2%), 23 sites with Average Risk Level (19,2%) and 32 sites with High Risk Level (26,6%). Near swimming pool and jacuzzi were the places with more High Risk Level classifications. In the selected establishment, was found that in the summer, after cleaning and disinfection, there were a greater number of sites classified as High Risk Level, and in winter it was found the opposite situation, being noted more places with High Risk Level before cleaning and disinfection. Next to swimming pool and access stairs to swimming pool and jacuzzi were the places with more High Risk Level classifications in Summer and Winter. Were isolated common fungi in surfaces and in workers. Prior to cleaning and disinfection 30,3% of fungi were isolated on surfaces and workers, and after 45,5% of fungi were also xxvii commonly isolated. The Yeasts were the most commonly isolated and the most frequent before and after surfaces cleaning and disinfection, and also in workers biological samples, were Rhodotorula genera and Candida parapsilosis, allowing confirming that workers fungal infection is related with surfaces fungal contamination. It was concluded that Occupational Health intervention it is necessary, in environmental monitoring and health surveillance perspective, in order to reduce fungal infections prevalence. To achieve this objective, preventive measures implementation it’s recommended, including: surfaces fungal contamination control, through effective cleaning and disinfecting in order to minimize surfaces fungal contamination; early infection identification by performing periodic biological sampling from workers, included in a health surveillance protocol; and also personal hygiene and diseases treatment awareness. Application of the created method to establish pattern for surfaces fungal occupational exposure, will be useful not only for estimating workers from gymnasiums with swimming pools fungal infection risk, but also to facilitate fungal reference values stipulation, effective and corrective measures implementation, and also, fungal infections prevention, not only in gymnasiums with swimming pool, but also in other professional settings.----------------- RÉSUMÉ - Les travailleurs des gymnases avec des piscines présentent souvent des infections fongiques, telles que Tinea pedis et aussi des onychomycoses, dues à leur activité professionnel, parce qu’ils restent plus longtemps tout prés des surfaces avec une certaine contamination fongique. Toute cette situation est due non seulement parce qu’ils sont ceux qui fréquentent plus souvent les places plus contaminées: des balnéaires, des vestiaires et des zones autour des piscines, mais aussi ils réalisent des activités aux pieds nus ou avec des chaussures très fermés et encore quelques fois avec des vêtements synthétiques. Tout cela emmène à une grande sudation ce qui aidera au développement fongique. Un objective de ce travaille a été connaître le risque d’infection et/ou présence de lésion (Tinea pedis et des onychomycoses) dans les travailleurs des gymnases avec des piscines et leur éventuel rapport avec l’exposition à la contamination fongique (de l’air et des surfaces) dans leurs locaux de travaille. On a décrit aussi des variables d’environnement et biologiques qui ont une certaine influence dans les infections fongiques dans tout l’environnement professionnel et aussi approfondir des éventuels associations entre ces même variables. On a encore reconnu des différences de la contamination fongique avant et après des lavages et désinfection de ces surfaces. Aussi on a trouvé des différences de contamination en Été et en Hiver. Cet étude a un composante transversale, en visant la description des phénomènes de contamination fongique biologique et de l'environnement dans un environnement professionnel et l’étude des associations possibles entre les variables; une composante longitudinale dans laquelle ils étaient connus comme des variations saisonnières de la contamination fongique des surfaces, et même; un quasi-composante expérimentale, où elle a examiné la répartition des champignons surfaces avant et après le lavage et la désinfection. Dans la composante transversale on été considérés 1 échantillons de 10 gymnases avec des piscines et un autre échantillon de au moins 10 professionnels de chaque établissement dans un total 124 travailleurs (75 hommes - 60,48% et 49 femmes - 39,52%). On a réalisé 258 prélèvements aux pieds des travailleurs et on a effectué en simultané la validation par contamination fongique de l’environnement par 50 prélèvements de l’air et par 120 prélèvements de surfaces (60 avant et 60 après des lavages et des désinfections) et on a effectué leur traitement en laboratoire et l’identification fongique. On a fait aussi l’évaluation des variables de l’environnement, la température, l’humidité relative et la vitesse de l’air. On a remplie 10 tableaux xxix d’observation, avec l’objective d’obtenir des informations sur les variables qu’influenceront l’exposition occupationnel aux souches fongiques, et encore 124 tableaux d’observation liée au prélèvement du matériel biologique, pour réaliser le registre des professionnels avec des lésions et des autres informations pertinentes pour une analyse laboratoire. Tous ces 124 travailleurs ont rempli un questionnaire au même temps que les prélèvements biologiques, afin de connaître quelques variables individuels et professionnels importants pour cet étude. Dans un des établissements on a aussi étudié les différences fongiques des surfaces parmi avant et après les lavages et de la désinfection et encore parmi l’Été et l’Hiver. Dans ce même établissement on a réalisé 36 prélèvements des surfaces avant et 36 après des lavages et de la désinfection, pendant 6 jours différents de la semaine, pendant 6 semaines en chaque saison de l’année, dans un total de 72 prélèvements des surfaces. On a encore crié et appliqué une méthode pour établir un standard d’exposition professionnelle au fungi sur les surfaces, afin de permettre la définition des niveaux semi quantitative d’estimation des risques d’infection fongique des travailleurs des gymnases avec des piscines. Pour le critère de Gravité, il a été considéré que la gravité de la contamination, et donc les possibles dommages, est étroitement liée aux espèces fongiques impliquées. Nous avons calculé la moyenne de la contamination fongique par chaque établissement avant le lavage et la désinfection afin d'établir les niveaux de Fréquence et, par rapport à l'Exposition, ont été crées pour regrouper les intervalles d'heures hebdomadaires consacrées à l'activité professionnelle en question. Sur les 124 travailleurs qui ont participé à l'étude, 58 (46,8%) avaient des lésions visibles. Parmi ces 58, les Levures ont été les plus isolées (41,4%), suivis par des Dermatophytes (24,1%) et des Filamenteux Non Dermatophytes (6,9%). Candida parapsilosis and Rhodotorula sp. ont été les Levures les plus fréquemment isolées (20,2%); dans le cas des Dermatophytes, Trichophyton rubrum est le plus fréquent (55,5%) et pour les Filamenteux Non Dermatophytes, Penicillium sp. a été le plus isolé (15,6%), suivi par Fusarium sp. (12,5%). En ce qui concerne la contamination fongique des surfaces, 37 champignons filamenteux ont été isolés. Le genre Fusarium est le plus fréquent avant et après le lavage et la désinfection (19,1% - 17,2%). Pour la levure, 12 levures différentes ont été identifiées, ayant été Cryptococcus sp. (40,6%) et Candida sp. (49,3%) les plus fréquents avant et après le lavage et la désinfection, respectivement. En ce qui concerne la contamination fongique de l'air, on a identifié 25 différents champignons filamenteux, où les 3 genres les plus fréquemment isolés étaient Cladosporium (36,6%), Penicillium (19,0%) et Aspergillus (10,2%). Pour les levures, il a été identifié le genre xxx Rhodotorula (87,5%) et les espèces Trichosporon mucoides et Cryptococcus unigutulattus (12,5%). On a vérifié une association, au niveau de signification de 5%, entre les lésions visibles et les heures hebdomadaires et entre les lésions visibles et la durée d’occupation, ce qui confirme l'influence de la durée de l'exposition aux facteurs de risque (contamination fongique dans le milieu de travail) pour la présence des lésions visibles chez les travailleurs exposés (Tinea pedis et onychomycose), en démontrant une relation entre l'exposition au facteur de risque dans ces études - l'exposition professionnelle aux champignons - avec les effets sur la santé. Les variables environnementales évalué (température, humidité relative et la vitesse de l'air) ne modifient pas la contamination fongique de l'air et des surfaces; donc, n'a pas été démontré aucune relation statistiquement significative (p>0,05). Cependant, il y a une influence du nombre d'occupants qui ont participé à chacun des établissements en moyenne des unités formant colonie par mètre carré sur la surface avant le lavage et la désinfection. Il n'y avait pas de corrélation entre les résultats quantitatifs de la contamination fongique de l'air et des surfaces des 10 établissements surveillés, cependant il existe des différences importantes, au niveau de signification de 10% entre la contamination fongique des surfaces et de la contamination fongique de l'air (p <0,1), on a constaté que malgré 50% des niveaux les plus bas étaient plus élevés dans la contamination fongique de l'air, la contamination fongique des surfaces présentée une plus grande variabilité quantitativement. En ce qui concerne les différences de la contamination fongique des surfaces dans les 10 établissements entre avant et après le lavage et la désinfection, il y avait seulement une réduction significative (p<0,05) de la contamination fongique après le lavage et la désinfection dans les balnéaires et vestiaires pour les hommes par rapport aux levures. Lors de l'établissement choisi, on a constaté que le rapport entre la contamination fongique et la température et l'humidité relative n'était pas significatif (p>0,05) dans les deux saisons et aussi on n’a pas observé l'influence des occupants en moyenne des unités formant colonie par mètres carrés de surfaces avant le lavage et la désinfection dans les deux saisons de l'année. Dans presque toutes les situations ou on a vérifié des différences significatives entre les deux saisons, il ya eu une augmentation des unités formant des colonies par mètre carré en Hiver, à l'exception du total des unités formant des colonies par mètre carré avant le lavage et désinfection dans les balnéaires et vestiaires des hommes où il y a eu une augmentation en Été. On a également été constaté que seulement a eu une réduction de la contamination des xxxi champignons après la désinfection de l'escalier d'accès en Hiver et dans les balnéaires et vestiaires des hommes en Été. Avec la méthode pour établir standard d’exposition professionnelle au fungi sur les surfaces on a obtenu dans les 10 établissements, avec le Niveau de Risque Faible de 65 places (54,2%), avec le Niveau de Risque Moyen 23 places (19,2%) et 32 places avec le Niveau de Risque Élevé (26,6%). Près du jacuzzi et près de la piscine sont les lieux avec des plus évaluations de Niveau de Risque Élevé. Lors de l'établissement choisi, il a été constaté que, dans l'Été, après le lavage et la désinfection, un plus grand nombre de places évaluées comme présentant un Niveau de Risque Élevé et en Hiver on a constaté la situation inverse avec de nombreux points de Niveau de Risque Élevé avant le lavage et la désinfection. A côté de la piscine et les escaliers ont été les lieux avec plus grands classifications de Niveau de Risque Élevé en Été et en Hiver. On a isolé, chez les travailleurs, des champignons communs aux isolés sur les surfaces. Avant le lavage et la désinfection, 30,3% des champignons ont été isolés sur les travailleurs et sur les surfaces et, après ces procédures, 45,5% des champignons ont été isolés fréquemment. Les levures les plus souvent isolées et les plus fréquentes avant et après le lavage et la désinfection des surfaces, et aussi dans les résultats d'échantillons biologiques prélevés sur les travailleurs, étaient du genre Rhodotorula et les espèces de Candida parapsilosis, ce qui permet confirmer que l'infection fongique des travailleurs est liée à la contamination fongique des surfaces. On a conclu qu’il est nécessaire l'intervention en Santé Occupationnelle sous la surveillance de l'environnement et sous la surveillance de la santé, afin de réduire la prévalence des infections fongiques. Pour atteindre cet objectif, nous suggérons la mise en oeuvre de mesures préventives, y compris: le contrôle de la contamination fongique des surfaces par des méthodes de lavage et de désinfection afin de minimiser la contamination fongique des surfaces, l'identification précoce de l'infection avec des prélèvements biologiques périodiques, notamment un protocole pour la surveillance de la santé, et aussi la conscience du sens de l'hygiène personnelle et le traitement des pathologies. La méthode mise en place pour l’établissement d’un standard d’exposition professionnelle au fungi sur les surfaces, servira à estimer non seulement le risque d'infection fongique des travailleurs dans les gymnases avec des piscines, mais aussi pour faciliter l'établissement de valeurs de référence de champignons, l'application des mesures correctives immédiates et appropriées, et aussi la prévention des infections fongiques, non seulement dans les gymnases avec piscine, mais aussi dans d'autres contextes professionnels.

Novel approaches for culturing hepatocytes for drug testing applications

Dissertation presented to obtain the Ph.D degree in Biochemisry, Biotechnology

Retaining MBAs, from employees' point of view

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Predictability of stock market returns: Evidence from Eurozone's banking sectors

This paper analyzes the in-, and out-of sample, predictability of the stock market returns from Eurozone’s banking sectors, arising from bank-specific ratios and macroeconomic variables, using panel estimation techniques. In order to do that, I set an unbalanced panel of 116 banks returns, from April, 1991, to March, 2013, to constitute equal-weighted country-sorted portfolios representative of the Austrian, Belgian, Finish, French, German, Greek, Irish, Italian, Portuguese and Spanish banking sectors. I find that both earnings per share (EPS) and the ratio of total loans to total assets have in-sample predictive power over the portfolios’ monthly returns whereas, regarding the cross-section of annual returns, only EPS retain significant explanatory power. Nevertheless, the sign associated with the impact of EPS is contrarian to the results of past literature. When looking at inter-yearly horizon returns, I document in-sample predictive power arising from the ratios of provisions to net interest income, and non-interest income to net income. Regarding the out-of-sample performance of the proposed models, I find that these would only beat the portfolios’ historical mean on the month following the disclosure of year-end financial statements. Still, the evidence found is not statistically significant. Finally, in a last attempt to find significant evidence of predictability of monthly and annual returns, I use Fama and French 3-Factor and Carhart models to describe the cross-section of returns. Although in-sample the factors can significantly track Eurozone’s banking sectors’ stock market returns, they do not beat the portfolios’ historical mean when forecasting returns.

Development of 3D in vitro models for prediction of hepatic metabolism and toxicity

The development of human cell models that recapitulate hepatic functionality allows the study of metabolic pathways involved in toxicity and disease. The increased biological relevance, cost-effectiveness and high-throughput of cell models can contribute to increase the efficiency of drug development in the pharmaceutical industry. Recapitulation of liver functionality in vitro requires the development of advanced culture strategies to mimic in vivo complexity, such as 3D culture, co-cultures or biomaterials. However, complex 3D models are typically associated with poor robustness, limited scalability and compatibility with screening methods. In this work, several strategies were used to develop highly functional and reproducible spheroid-based in vitro models of human hepatocytes and HepaRG cells using stirred culture systems. In chapter 2, the isolation of human hepatocytes from resected liver tissue was implemented and a liver tissue perfusion method was optimized towards the improvement of hepatocyte isolation and aggregation efficiency, resulting in an isolation protocol compatible with 3D culture. In chapter 3, human hepatocytes were co-cultivated with mesenchymal stem cells (MSC) and the phenotype of both cell types was characterized, showing that MSC acquire a supportive stromal function and hepatocytes retain differentiated hepatic functions, stability of drug metabolism enzymes and higher viability in co-cultures. In chapter 4, a 3D alginate microencapsulation strategy for the differentiation of HepaRG cells was evaluated and compared with the standard 2D DMSO-dependent differentiation, yielding higher differentiation efficiency, comparable levels of drug metabolism activity and significantly improved biosynthetic activity. The work developed in this thesis provides novel strategies for 3D culture of human hepatic cell models, which are reproducible, scalable and compatible with screening platforms. The phenotypic and functional characterization of the in vitro systems performed contributes to the state of the art of human hepatic cell models and can be applied to the improvement of pre-clinical drug development efficiency of the process, model disease and ultimately, development of cell-based therapeutic strategies for liver failure.

The impact of talent management practices on employee retention: The moderator effect of leader-member exchange and role modeling

Organizations are undergoing serious difficulties to retain talent. Authors argue that Talent Management (TM) practices create beneficial outcomes for individuals and organizations. However, there is no research on the leaders’ role in the functioning of these practices. This study examines how LMX and role modeling influence the impact that TM practices have on employees’ trust in their organizations and retention. The analysis of two questionnaires (Nt1=175; Nt2=107) indicated that TM only reduced turnover intentions, via an increase in trust in the organization, when role modeling was high and not when it was low. Therefore, we can say that leaders are crucial in the TM context, and in sustaining a competitive advantage for organizations.

Hotel industry: An answer to the emerging trends on the global demand side of tourism

This dissertation studies essentially how Millennials are changing the hotel industry, in the sense that new trends are emerging with this generation and hotels need to respond accordingly, in order to survive within their competitive industry. Emphasis is also given to Asian travellers, as the enlargement of these countries’ middle class populations is predicted, therefore making Asian travellers a valuable target for the hotel industry. To successfully target this segment, hoteliers need also to consider the cultural differences and aspirations that come together with the Asian travellers, and appropriately adapt their offer to them. I will then redirect this study to the city of Lisbon, the Portuguese capital, to analyse if Lisbon’s four and five-star hotel managers are aware of the new market trends, and to understand how they are changing their hotels in order to make them more attractive to Millennials and Asian travellers. Using a sample of 12 hotels (four and five-stars ratings), I have concluded that, although there is a notable undergoing process of adaptation to these guests, there is a long way ahead in order for Lisbon’s hotels to entirely please and retain millennial guests.

Developing a gamification system to increase customer lifetime value at MyGon

There have never been so many touch points between companies and consumers as there are today, which paradoxically makes it very challenging for companies to be able to retain and engage customers. Gamification is a strategy used by a large number of companies to increase customer engagement and customer lifetime value. This work aims at developing a gamification system for MyGon, a Portuguese startup working in the market of discounts and experiences. In addition to examining the literature concerning gamification, its elements and characteristics, recommendations were developed for addressing MyGon’s business goals of increasing conversion and customer engagement. The gamification mechanisms suggested include badges, missions, points, leaderboards and levels.

How small accounting firms can compete in an environment in which the big four are getting bigger

This paper sets out to determine how small accounting firms can compete in the United States in the early 21st century. The first chapter identifies the central goal of the paper: namely, to use existing literature and market data to define a business strategy for Ross & Moncure, Inc., a small accounting firm in the metropolitan Washington area. The second chapter is a literature review, and in it the author finds that large accounting firms are advantaged in terms of reputation, ability to diversify, and ability to retain employees, but are disadvantaged in their ability to form longstanding successful relationships with clients. In the third chapter, the author explores the relationship between the Big Four firms and their employees. The goal of this chapter is to determine how small accounting firms can compete for top talent in the HR market, and the author finds that this can be done by offering faster career progression and more client interaction. The fourth chapter looks at the market for accounting services in the United States, exploring the different options that consumers have to meet their accounting needs. It is found in this chapter that big and small accounting firms tend to compete for clients of different profiles. In the fifth chapter, the author uses proprietary company data to explore the composition, existing strategy and culture of Ross & Moncure. In the sixth chapter, all of the previous chapters come together to formulate a strategy and plan for action for Ross & Moncure: specifically, that the firm should further cultivate networks and relationships, and should create a fulfilling professional environment by increasing client-employee interaction, encouraging external education, and allowing employees to take on many different projects

Developing a gamification system to increase customer lifetime value at MyGon

There have never been so many touch points between companies and consumers as there are today, which paradoxically makes it very challenging for companies to be able to retain and engage customers. Gamification is a strategy used by a large number of companies to increase customer engagement and customer lifetime value. This work aims at developing a gamification system for MyGon, a Portuguese startup working in the market of discounts and experiences. In addition to examining the literature concerning gamification, its elements and characteristics, recommendations were developed for addressing MyGon’s business goals of increasing conversion and customer engagement. The gamification mechanisms suggested include badges, missions, points, leaderboards and levels.

Finding the hidden influencers

This thesis is a first step in the search for the characteristics of funders, and the underlying motivation that drives them to participate in crowdfunding. The purpose of the study is to identify demographics and psychographics that influence a funder’s willingness to financially support a crowdfunding project (WFS). Crowdfunding, crowdsourcing and donation literature are combined to create a conceptual model in which age, gender, altruism and income, together with several control variables, are expected to have an influence on a funder’s WFS. Primary data collection was conducted using a survey, and a dataset of 175 potential crowdfunders was created. The data is analysed using a multiple regression and provided several interesting results. First of all, age and gender have a significant effect on WFS, males and young adults until the age of 30 have a higher intention to give money to crowdfunding projects. Second, altruism is significantly positively related to WFS, meaning that the funders do not just care about the potential rewards they could receive, but also about the benefits that they create for the entrepreneur and the people affected by the crowdfunding project. Third, the moderation effect of income was found to be insignificant in this model. It shows that income does not affect the strength of the relationship between the age, gender and altruism, and WFS. This study provides important theoretical contributions by, to the best of my knowledge, being the first study to quantitatively investigate the characteristics of funders and using the funder as the unit of analysis. Moreover, the study provides important insights for entrepreneurs who wish to target the crowd better in order to attract and retain more funders, thereby increasing the chance of success of their project.