Recently, self-healing applications of cement-based materials have received a lot of interest. One major area of interest with respect to self-healing applications in cement-based systems focuses on using biomineralization processes. Biomineralization is biochemical process in which microorganisms stimulate the formation of minerals. The existing research on biomineralization in cement-based systems has showed promising results and the studies suggest that biomineralization could be a useful approach for remediation of cracks on the surface of concrete. This dissertation presents the results of an intensive study undertaken to understand the influence of vegetative bacteria, specifically Sporosarcina pasteurii (S. pasteurii), when it is incorporated within cement paste. Vegetative S. pasteurii cells were suspended in a urea-yeast extract medium and this medium was mixed with cement. The influence of the vegetative S. pasteurii cells on Portland cement paste properties, such as compressive strength, hydration kinetics, and setting time was evaluated. It was determined that the hydration kinetics was highly influenced when the bacterial medium was used to prepare cement paste, and severe retardation was observed. It was also observed that an increase in calcium carbonate precipitation, particularly calcite, occurred within cement paste when the bacterial medium was used. Furthermore, use of the bacterial medium resulted in reducing the porosity and increasing the compressive strength of the hardened paste. Ex-situ culture experiments were conducted to determine the impact of pH and calcium concentration on the morphology of calcium carbonate precipitate; the results indicated that the morphology of the precipitate was more influenced by calcium concentration. A key focus of this dissertation was to examine the viability of the vegetative cells that were inoculated in cement paste. Viable S. pasteurii cells were found to be present in hardened cement paste samples that were as old as 330-days, and 50% of the viable cells detected were defined as vegetative cells. At last, the use of including internal nutrient reservoirs as a means to extend the viability of the bacterial cells within hardened cement paste was explored. The results showed that the percentage of vegetative cells remaining was affected when internal nutrient reservoirs was incorporated into the system. / text

O presente estudo buscou averiguar a relação de manejos nutricionais diferenciados no terço final de gestação associados ou não ao emprego de gonadotrofinas exógenas no pós-desmame com a manifestação da redução da segunda leitegada em fêmeas suínas. O experimento foi realizado no Laboratório de Pesquisa em Suínos (VNP-FMVZ-USP) Pirassununga/SP. Foram utilizadas 23 marrãs prenhes, sendo empregado o delineamento experimental inteiramente casualizado em arranjo fatorial de tratamentos, sendo um fator o manejo nutricional a partir de 75 &plusmn; 1,74 dias de gestação, fornecendo-se 2,9 kg/dia de ração de pré-lactação (P; 3.203 kcal EM/kg, 17,25% PB) ou 2,5 kg/dia de ração de gestação (G; 2.930 kcal EM/kg, 16,43% PB) e o segundo a aplicação hormonal - 600UI de eCG e, após 72 horas, 2,5mg de LH porcino - no dia do desmame (H) ou não (C). Semanalmente, entre o 82º dia de gestação e o dia do desmame, se averiguou o peso vivo dos animais e colheram-se amostras de sangue para avaliação de parâmetros de bioquímica sanguínea, sendo as fêmeas abatidas 4,55 ± 0,92 dias após a inseminação artificial pós-desmame para colheita e avaliação de embriões. Fêmeas do tratamento P apresentaram maior ganho de peso diário (p<0,050) em três das cinco semanas do terço final de gestação avaliadas, obtendo maior ganho de peso geral entre o 75º dia de gestação e a avaliação pré parto (p<0,001). Na fase de lactação, o tratamento P apresentou maior perda de peso na 1ª (p=0,038) e 3ª (p=0,061) semanas. Não foram observadas diferenças no tocante ao consumo de ração na lactação, desempenho da leitegada ou retorno a atividade reprodutiva pós-desmame. Na avaliação dos embriões, foi observada interação entre os fatores para a variável porcentagem de estruturas fecundadas (p=0,051), obtendo-se valores de 98,55%, 78,97%, 96,88% e 99,09% para GC, GH, PC e PH, respectivamente. Tal resultado sugere uma participação do estado metabólico sobre a resposta à hormonioterapia, devendo estes mecanismos serem objeto de estudos mais específicos. Animais submetidos ao protocolo hormonal apresentaram maior porcentagem de embriões na fase de mórula (p=0,050). As alterações de qualidade embrionária associadas à utilização de gonadotrofinas exógenas podem estar ligadas a mudanças no desenvolvimento folicular, levando a ovulação de oócitos de qualidade inferior e desenvolvimento alterado dos futuros embriões. Animais alimentados com ração de pré-lactação apresentaram maiores níveis de colesterol total e suas frações (HDL, LDL e VLDL) na fase de gestação, ligados à maior ingestão de nutrientes e substratos energéticos, e maiores concentrações de ácidos graxos não esterificados (AGNE) no momento do parto e durante a lactação, associados à maior mobilização de reservas corporais. No contexto experimental apresentado, pode-se inferir que o catabolismo na fase de lactação, quando moderado e acompanhado de maiores reservas no momento do parto, não interferiu significativamente no desempenho reprodutivo pós-desmame. A indução de quadros mais severos de catabolismo lactacional pode contribuir para o esclarecimento dos reflexos deste estado metabólico sobre a atividade reprodutiva de fêmeas suínas. / The present study evaluated the relationship between different nutritional managements in the last third of gestation associated or not with exogenous gonadotropins hormonal protocol at weaning and the manifestation of second litter reduction in female swine. The experiment was carried out in the Laboratory of Swine Research (VNP-FMVZ-USP) Pirassununga/SP. Twenty three (23) pregnant gilts were used in a completely random factorial design, with one factor being the nutritional management from 75 &plusmn; 1,74 days of gestation onward, feeding animals with 2,9 kg/day of a pre-lactation diet (P; 3.203 kcal ME/kg, 17,25% CP) or 2,5 kg/day of a gestation diet (G; 2.930 kcal ME/kg, 16,43% CP), and the second factor being the hormonal protocol 600IU of eCG and, after 72 hours, 2,5mg of porcine LH administration (H) or not (C) at weaning. Weekly, from day 82 of gestation until weaning, body weight were measured and blood samples were collected for determinations of serum bioquimical parameters. Females were slaughtered 4,55 ± 0,92 days after artificial insemination for embryo collection and evaluation. Animals in the P treatment showed higher body weight gains (p<0,050) un three of the five weeks evaluated in the late gestation, obtaining higher overall weight gain between days 75 of gestation and the pre partum evaluation (p<0,001). In the lactation period, treatment P showed higher weight losses in the 1st(p=0,038) and 3rd(p=0,061) weeks. No differences in feed consumption during lactation, litter performance and post weaning return to reproductive activity were observed. In the embryo evaluation, an interaction between factors was observed for the percentage of fecundated structures (p=0,051), with values of 98,55%, 78,97%, 96,88% e 99,09% for GC, GH, PC e PH, respectively. Such result indicates a effect of the metabolic state on the response to the hormonal therapy, with the need of further studying the mechanisms involved. Animals submitted to the hormonal protocol showed a higher percentage of embryos in the morula stage (p=0,050). Changes in embryo quality associated with the administration of exogenous gonadotropins might be linked to shifts in follicular growth, leading to the ovulation of oocites of lower quality and altered future embryo development. Females fed the pre-lactation diet had higher total cholesterol and fractions (HDL, LDL, VLDL) in the gestation period, which is linked to the higher consumption of energy yielding substances, and higher concentrations of non-sterified fatty acids (NEFA) during farrowing and lactation, which are related to more severe fat mobilization. In the context of the present experiment, the catabolism during lactation, when moderate and accompanied by higher body reserves at farrowing, did not significantly interfere with the post-weaning reproductive performance. The induction of more severe catabolic states might contribute to enhance our knowledge on the effects of this metabolic state on the reproductive outcome of sows.

O presente estudo buscou averiguar a relação de manejos nutricionais diferenciados no terço final de gestação associados ou não ao emprego de gonadotrofinas exógenas no pós-desmame com a manifestação da redução da segunda leitegada em fêmeas suínas. O experimento foi realizado no Laboratório de Pesquisa em Suínos (VNP-FMVZ-USP) Pirassununga/SP. Foram utilizadas 23 marrãs prenhes, sendo empregado o delineamento experimental inteiramente casualizado em arranjo fatorial de tratamentos, sendo um fator o manejo nutricional a partir de 75 &plusmn; 1,74 dias de gestação, fornecendo-se 2,9 kg/dia de ração de pré-lactação (P; 3.203 kcal EM/kg, 17,25% PB) ou 2,5 kg/dia de ração de gestação (G; 2.930 kcal EM/kg, 16,43% PB) e o segundo a aplicação hormonal - 600UI de eCG e, após 72 horas, 2,5mg de LH porcino - no dia do desmame (H) ou não (C). Semanalmente, entre o 82º dia de gestação e o dia do desmame, se averiguou o peso vivo dos animais e colheram-se amostras de sangue para avaliação de parâmetros de bioquímica sanguínea, sendo as fêmeas abatidas 4,55 ± 0,92 dias após a inseminação artificial pós-desmame para colheita e avaliação de embriões. Fêmeas do tratamento P apresentaram maior ganho de peso diário (p<0,050) em três das cinco semanas do terço final de gestação avaliadas, obtendo maior ganho de peso geral entre o 75º dia de gestação e a avaliação pré parto (p<0,001). Na fase de lactação, o tratamento P apresentou maior perda de peso na 1ª (p=0,038) e 3ª (p=0,061) semanas. Não foram observadas diferenças no tocante ao consumo de ração na lactação, desempenho da leitegada ou retorno a atividade reprodutiva pós-desmame. Na avaliação dos embriões, foi observada interação entre os fatores para a variável porcentagem de estruturas fecundadas (p=0,051), obtendo-se valores de 98,55%, 78,97%, 96,88% e 99,09% para GC, GH, PC e PH, respectivamente. Tal resultado sugere uma participação do estado metabólico sobre a resposta à hormonioterapia, devendo estes mecanismos serem objeto de estudos mais específicos. Animais submetidos ao protocolo hormonal apresentaram maior porcentagem de embriões na fase de mórula (p=0,050). As alterações de qualidade embrionária associadas à utilização de gonadotrofinas exógenas podem estar ligadas a mudanças no desenvolvimento folicular, levando a ovulação de oócitos de qualidade inferior e desenvolvimento alterado dos futuros embriões. Animais alimentados com ração de pré-lactação apresentaram maiores níveis de colesterol total e suas frações (HDL, LDL e VLDL) na fase de gestação, ligados à maior ingestão de nutrientes e substratos energéticos, e maiores concentrações de ácidos graxos não esterificados (AGNE) no momento do parto e durante a lactação, associados à maior mobilização de reservas corporais. No contexto experimental apresentado, pode-se inferir que o catabolismo na fase de lactação, quando moderado e acompanhado de maiores reservas no momento do parto, não interferiu significativamente no desempenho reprodutivo pós-desmame. A indução de quadros mais severos de catabolismo lactacional pode contribuir para o esclarecimento dos reflexos deste estado metabólico sobre a atividade reprodutiva de fêmeas suínas. / The present study evaluated the relationship between different nutritional managements in the last third of gestation associated or not with exogenous gonadotropins hormonal protocol at weaning and the manifestation of second litter reduction in female swine. The experiment was carried out in the Laboratory of Swine Research (VNP-FMVZ-USP) Pirassununga/SP. Twenty three (23) pregnant gilts were used in a completely random factorial design, with one factor being the nutritional management from 75 &plusmn; 1,74 days of gestation onward, feeding animals with 2,9 kg/day of a pre-lactation diet (P; 3.203 kcal ME/kg, 17,25% CP) or 2,5 kg/day of a gestation diet (G; 2.930 kcal ME/kg, 16,43% CP), and the second factor being the hormonal protocol 600IU of eCG and, after 72 hours, 2,5mg of porcine LH administration (H) or not (C) at weaning. Weekly, from day 82 of gestation until weaning, body weight were measured and blood samples were collected for determinations of serum bioquimical parameters. Females were slaughtered 4,55 ± 0,92 days after artificial insemination for embryo collection and evaluation. Animals in the P treatment showed higher body weight gains (p<0,050) un three of the five weeks evaluated in the late gestation, obtaining higher overall weight gain between days 75 of gestation and the pre partum evaluation (p<0,001). In the lactation period, treatment P showed higher weight losses in the 1st(p=0,038) and 3rd(p=0,061) weeks. No differences in feed consumption during lactation, litter performance and post weaning return to reproductive activity were observed. In the embryo evaluation, an interaction between factors was observed for the percentage of fecundated structures (p=0,051), with values of 98,55%, 78,97%, 96,88% e 99,09% for GC, GH, PC e PH, respectively. Such result indicates a effect of the metabolic state on the response to the hormonal therapy, with the need of further studying the mechanisms involved. Animals submitted to the hormonal protocol showed a higher percentage of embryos in the morula stage (p=0,050). Changes in embryo quality associated with the administration of exogenous gonadotropins might be linked to shifts in follicular growth, leading to the ovulation of oocites of lower quality and altered future embryo development. Females fed the pre-lactation diet had higher total cholesterol and fractions (HDL, LDL, VLDL) in the gestation period, which is linked to the higher consumption of energy yielding substances, and higher concentrations of non-sterified fatty acids (NEFA) during farrowing and lactation, which are related to more severe fat mobilization. In the context of the present experiment, the catabolism during lactation, when moderate and accompanied by higher body reserves at farrowing, did not significantly interfere with the post-weaning reproductive performance. The induction of more severe catabolic states might contribute to enhance our knowledge on the effects of this metabolic state on the reproductive outcome of sows.

The seafood industry is of considerable importance to both the New Zealand and global economies and therefore tissue preservation technologies that increase product quality and/or prolong shelf life have the potential to add significant value. Technologies for maintaining the viability of isolated tissues also have a wide range of other medical and industrial applications. This thesis examines the relationship between metabolic function, oxidation and cell death and the resulting stability of the non-viable tissues during long term storage in chinook salmon (Oncorhynchus tshawytscha) red and white skeletal muscle tissue. This research also looks at the role of the aquatic anaesthetic AQUI-S™, in which the active ingredient is isoeugenol (a lipid soluble antioxidant), and other antioxidant compounds in preserving metabolic function in viable tissues and tissue stability in nonviable tissues. Perfusion of salmon tails at 15℃ over 5 or 10 hours with oxygen saturated saline resulted in significant increases in protein and lipid oxidation (protein carbonyl and TBARS concentrations respectively) in the red muscle, but not the white muscle. The introduction of ascorbic acid and uric acid into the saline did not reduce the oxidation in the red muscle despite significantly increasing their respective concentrations in the tissue. This indicates the difficulties associated with attempting to extend tissue viability by delivering free oxygen to the tissue and also highlights the difference in susceptibility of the two muscle types to oxidation. Tail fillets from salmon harvested in both rested and exhausted physiological states using AQUI-S™, and fillets from exhausted salmon harvested without AQUI-S™, were exposed to air at 15℃ for up to 96 hours. Protein carbonyls increased in a roughly linear fashion over the entire 96 hours in all three groups. Both lipid peroxides (TBARS) and uric acid concentrations began to increase in the exhausted group after 30 hours. In contrast, no significant increases in lipid peroxides or uric acid was seen in the fillets from either group harvested using AQUI-S™. Vitamin E concentrations reduced slowly but did not change significantly despite the oxidation that was evident in the tissue. These processes also occurred in salmon tail fillets during storage at 6℃. The measurement of ATP related compounds provides an effective indicator of both the metabolic state of the tissue post-harvest and the quality. The breakdown of these compounds is also associated with the production of ammonia and hydrogen peroxide. Fresh rested salmon fillets had high concentrations of ATP and creatine phosphate, which were both depleted after 12 hours storage at 15℃. This indicates that cell viability lasted a number of hours following harvesting. These metabolites were depleted in exhausted fillets and metabolic potential appeared to be immediately compromised. The concentration of the taste enhancing compound IMP was significantly reduced in fresh rested tissue, but increased during storage, and was significantly higher than in exhausted tissues following 12 hours of storage at 15℃. This indicates that some properties of rested tissues may improve with limited storage times. The accumulation of uric acid - the metabolic end point for ATP related compounds - was also significantly reduced in rested tissue and increases in K-value were slowed. AQUI-S™ showed an ability to preserve tissue function through its anaesthetic action allowing tissue to be harvested in a rested state, and to reduce late stage lipid oxidation in stored salmon tail fillets. The antioxidant action of isoeugenol in salmon fillets may be mediated through its ability to chelate transition metals released during tissue degradation. This research shows that during reperfusion and during fillet storage there is a significant level of oxidative stress, which needs to be minimized while maintaining basic tissue metabolism to prolong tissue and cellular viability. The development of future technologies to preserve tissue viability may depend on the development of a synthetic oxygen carrying compound with properties similar to red blood cells. This may allow more control over oxygen delivery, potentially reducing the oxidative stress associated with high concentrations of free oxygen in solution. However, preserving cell viability will also require the maintenance of endogenous antioxidant function and there is also the potential to use iron chelating compounds including plant derived flavonoids to preserve non-viable tissues. Future research in these areas is necessary.

Development of the advanced, real-time methods for monitoring of bioaerosols is becoming increasingly important. At present, the Ultraviolet Aerodynamic Particle Sizer (UVAPS, Model 3312, TSI, St. Paul., MN) is the only commercially available method for in-situ, continuous measurements of viable airborne microorganisms. Research included in this thesis aimed towards comprehensive evaluation of the method over a wide range of operating conditions, linking the experimental results to the theoretical basis of its design and operation, and to developing a scientific basis for its application to real-time monitoring of bioaerosols. Specifically, due to a growing concern in the general community about the environmental and health aspects of biological aerosols originated from various types of agricultural operations including animal farming, this research was focussed on developing a research methodology/strategy for applying the method to the investigation of bioaerosols in the swine confinement buildings (SCB). Investigations under controlled laboratory conditions were primarily concerned with selectivity, sensitivity, counting efficiency, and detection limits of the spectrometer. This study also examined the effect of physiological state (metabolic activity) of bacteria on the performance characteristics of the method. The practical implications of the research findings are discussed in this thesis. Further field investigations undertaken on a pig farm advanced understanding of the UVAPS performance in the real-life environmental settings. The research also provided a new insight on the particle size distribution and the effect of on-farm-activities on aerosol load inside the SCBs, for both biological and non-biological aerosols. This study has proved that the UVAPS is a powerful tool for investigation of viable bioaerosols in the environment. However, this method is limited to detection of active metabolising bacteria that excludes dormant bacterial spores. In addition, the method is very sensitive to physiological state of bacteria and to the effect of adverse environmental conditions on metabolic activity of airborne bacteria, which may decrease the amount of the intrinsic fluorophores in the cells below sensitivity level iv of the monitor. Possible limitations of this technology include also the lack of selectivity and thus interferences from the non-microbial organic components of airborne particles. In addition, the sensitivity of the method is insufficient for monitoring viable bacteria in the environments with relatively low concentrations of bioaerosols. In order to increase sensitivity of the method, it would be desirable to concentrate the bioaerosols into a smaller volume with the aim of high-volume virtual impactors (aerosol concentrators) prior to the monitoring. Therefore, in the indoor environments where an application of the concentrator is not feasible, the utilisation of the UVAPS may be problematic. Due to the intrinsic limitations, the method is not recommended for the direct measurements of viable bioaerosols and should be used in conjunction with the conventional biosamplers for obtaining more realistic insights into the microbial air quality. Nevertheless, the UVAPS has been found to be an adequate method for the investigation of the dynamics of biological aerosols in real-time. Overall, this thesis contributes to the advancing of the understanding of the method and may assist in developing new, more advanced technologies for the real-time monitoring of viable bioaerosols, as well as in developing sampling strategies for the application of the method to various bioaerosol studies.

The seafood industry is of considerable importance to both the New Zealand and global economies and therefore tissue preservation technologies that increase product quality and/or prolong shelf life have the potential to add significant value. Technologies for maintaining the viability of isolated tissues also have a wide range of other medical and industrial applications. This thesis examines the relationship between metabolic function, oxidation and cell death and the resulting stability of the non-viable tissues during long term storage in chinook salmon (Oncorhynchus tshawytscha) red and white skeletal muscle tissue. This research also looks at the role of the aquatic anaesthetic AQUI-S™, in which the active ingredient is isoeugenol (a lipid soluble antioxidant), and other antioxidant compounds in preserving metabolic function in viable tissues and tissue stability in nonviable tissues. Perfusion of salmon tails at 15℃ over 5 or 10 hours with oxygen saturated saline resulted in significant increases in protein and lipid oxidation (protein carbonyl and TBARS concentrations respectively) in the red muscle, but not the white muscle. The introduction of ascorbic acid and uric acid into the saline did not reduce the oxidation in the red muscle despite significantly increasing their respective concentrations in the tissue. This indicates the difficulties associated with attempting to extend tissue viability by delivering free oxygen to the tissue and also highlights the difference in susceptibility of the two muscle types to oxidation. Tail fillets from salmon harvested in both rested and exhausted physiological states using AQUI-S™, and fillets from exhausted salmon harvested without AQUI-S™, were exposed to air at 15℃ for up to 96 hours. Protein carbonyls increased in a roughly linear fashion over the entire 96 hours in all three groups. Both lipid peroxides (TBARS) and uric acid concentrations began to increase in the exhausted group after 30 hours. In contrast, no significant increases in lipid peroxides or uric acid was seen in the fillets from either group harvested using AQUI-S™. Vitamin E concentrations reduced slowly but did not change significantly despite the oxidation that was evident in the tissue. These processes also occurred in salmon tail fillets during storage at 6℃. The measurement of ATP related compounds provides an effective indicator of both the metabolic state of the tissue post-harvest and the quality. The breakdown of these compounds is also associated with the production of ammonia and hydrogen peroxide. Fresh rested salmon fillets had high concentrations of ATP and creatine phosphate, which were both depleted after 12 hours storage at 15℃. This indicates that cell viability lasted a number of hours following harvesting. These metabolites were depleted in exhausted fillets and metabolic potential appeared to be immediately compromised. The concentration of the taste enhancing compound IMP was significantly reduced in fresh rested tissue, but increased during storage, and was significantly higher than in exhausted tissues following 12 hours of storage at 15℃. This indicates that some properties of rested tissues may improve with limited storage times. The accumulation of uric acid - the metabolic end point for ATP related compounds - was also significantly reduced in rested tissue and increases in K-value were slowed. AQUI-S™ showed an ability to preserve tissue function through its anaesthetic action allowing tissue to be harvested in a rested state, and to reduce late stage lipid oxidation in stored salmon tail fillets. The antioxidant action of isoeugenol in salmon fillets may be mediated through its ability to chelate transition metals released during tissue degradation. This research shows that during reperfusion and during fillet storage there is a significant level of oxidative stress, which needs to be minimized while maintaining basic tissue metabolism to prolong tissue and cellular viability. The development of future technologies to preserve tissue viability may depend on the development of a synthetic oxygen carrying compound with properties similar to red blood cells. This may allow more control over oxygen delivery, potentially reducing the oxidative stress associated with high concentrations of free oxygen in solution. However, preserving cell viability will also require the maintenance of endogenous antioxidant function and there is also the potential to use iron chelating compounds including plant derived flavonoids to preserve non-viable tissues. Future research in these areas is necessary.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal