<p>Sorghum [<i>Sorghum bicolor</i> (L.) Moench] is a staple food for millions of people in Africa and South Asia. It is mainly consumed for its starch. The starch composition and structure in the seed endosperm determines cooking properties, processing quality, and starch digestibility. </p> <p>An assay to measure the alkali spreading value (ASV) of sorghum is described. The assay was used to identify sorghum EMS mutants with variation in starch composition. The ASV mutants (ASV+) exhibited a range of starch thermal properties with starch gelatinization temperatures (GT) being lower or higher than samples from Tx623 or Sepon82. The ASV+ phenotypes were found to be correlated with starch related traits such as enthalpy (r = −0.53) and range of starch GT (T_c-T_o) (r = 0.60). </p> <p>Genes controling the ASV phenotype of sorghum and their impact on starch quality traits are described. Whole genome re-sequencing of sorghum EMS mutants exhibiting an ASV+ phenotype was used to identify single nucleotide polymorphisms (SNPs) in candidate genes <i>Sobic.004G163700</i> and <i>Sobic.010G093400</i>. The two genes were identified as a <i>SbeIIb</i>, a putative sorghum homolog of <i>amylose extender,</i> and as a <i>SSIIa</i>, respectively. Linkage analysis showed that the mutations in <i>Sobic.010G093400</i> and <i>Sobic.004G163700</i> co-segregated with the ASV phenotype. The <i>ssIIa</i>-mutants exhibited normal amylose values, lower starch GT and lower final viscosity than the wild type. The <i>sbeIIb</i>-mutants exhibited higher amylose content, higher starch GT and lower peak and final viscosity with poor gel consistency compared to the wild type and <i>ssIIa</i>-mutants. An allele dosage test indicated that the <i>sbeIIb</i>-mutants had an allele dosage dependent effect on amylose content. Double mutants of <i>sbeIIb</i> and <i>ssIIa</i> showed that amylose content, starch thermal properties and paste viscosity profiles resemble the <i>sbeIIb</i> parent. </p> <p>A study of ASV phenotypes in a panel of more than 750 sorghum conversion lines revealed genetic variation for the ASV phenotype. A few SC-lines exhibiting stable expression of the ASV+ phenotype over two growing seasons. Most of these lines were described as belonging to the working group Nandyal, durra types from India described as producing ‘glutinous grains’. Whole genome resequencing discovered common SNPs in genes associated with starch biosynthesis. A genome wide association study (GWAS) identified a significant SNP that could be associated with the starch biosynthesis gene <i>Sobic.010G273800</i>, and with candidate genes <i>Sobic.010G274800</i> and <i>Sobic.010G275001</i> both annotated as glucosyltransferases. Grain samples from SC489, SC491, SC587 and SC589 exhibited a consistent ASV+ phenotype with lower or similar starch GT, similar amylose content, and similar high viscosity and gel consistency compared to controls.</p> <p> </p>

7 ABSTRACT (EN) This dissertation thesis is focused on the study of electrochemical properties of new types of carbon paste electrodes (CPE) and carbon fiber rod electrodes (CFRE), which were used for the development of new highly sensitive and selective voltammetric and amperometric methods for the determination of 5-amino-6-nitroquinoline and trans- and cis- isomers of resveratrol. The carbon paste electrodes were compared in terms of size of the microparticles of glassy carbon contained in the paste (diameters 0.4 - 12 µm; 10 - 20 µm; 20 - 50 µm) in comparison with carbon paste electrode consisting of crystalline graphite and solid glassy carbon electrode. The electrochemical properties were tested using potassium hexacyanoferrate in an aqueous supporting electrolyte and 5-amino-6-nitroquinoline (5A6NQ) in a mixed methanol-water supporting electrolyte. The carbon paste electrode was further used in an amperometric detector of a wall-jet type connected in series with a spectrophotometric detector for the development of a new HPLC method with electrochemical detection and spectrophotometric detection for the determination of trans-resveratrol and cis-resveratrol in samples of grains, hulls and leaves of common and tartary buckwheat. The method was optimized and used for the determination of resveratrol in...

Neste trabalho foi realizada a funcionalização de grafite sem prévio tratamento em condições de Fridel-Crafts. Considerando que a grafite não possui hidrogênio em sua estrutura, não se observa uma reação de substituição eletrofílica. Por outro lado, o trabalho mostra o papel da umidade presente no grafite na reação de funcionalização. Dessa forma, foi proposto um mecanismo para a reação com a participação da água adsorvida na grafite estabilizando o carbocátion formado. O grafite funcionalizado obtido na reação foi utilizado como material eletródico. Para a reação de funcionalização, quatro moléculas foram utilizadas: ácido ferrocenomonocarboxílico, cloreto de 4-nitrobenzoíla, cloreto de 3,5-dinitrobenzoíla e ácido 3,4-dinitrobenzóico. Para o estudo das condições ótimas da reação, utilizou-se diferentes potências de radiação no reator de micro-ondas, sendo que a extensão da funcionalização mostrou-se sensível à variação deste parâmetro. Para a caracterização dos materiais, utilizou-se voltametria cíclica e análise térmica (TG e DTA). Resultados de infravermelho e Ramam são apresentados no Apêndice A. Os resultados eletroquímicos mostraram que os materiais funcionalizados em maiores potências apresentaram maior corrente Faradaica, mas ao mesmo tempo, o material obtido foi mais resistivo. A diferença de potencial relacionada ao processo redox do ferroceno aumentou conforme a extensão da funcionalização, uma vez que um sobrepotencial é necessário devido ao fluxo iônico (para a manutenção da eletroneutralidade) relativo ao número de espécies envolvidas. Os resultados eletroquímicos também indicaram que a funcionalização do grafite com os nitro compostos foi baixa. A análise térmica evidenciou que a reação de funcionalização do grafite com o ferroceno resultou em materiais com 15% a 20% (m/m) de material ligado ao grafite. Os materiais funcionalizados a maiores potências apresentaram maior massa ligada ao grafite. A funcionalização com os nitro compostos resultou em materiais com menos de 3% (m/m) de composto ligado ao grafite. Os resultados das duas técnicas mostraram coerência na análise da extensão da funcionalização. O material funcionalizado com o ácido ferrocenomonocarboxilico foi o que apresentou os melhores resultados e propõe-se uma explicação para tal baseado no mecanismo de reação sugerido. Com o objetivo de melhor elucidar o mecanismo da reação, foram realizadas algumas reações na ausência de alguns reagentes. Por exemplo, quando tenta-se funcionalizar o material sem a presença de cloreto de alumínio ou sem a umidade natural do grafite, a reação não ocorre. / In this work natural graphite functionalization in Fridel-Crafts conditions is performed using a one-step microwave assisted reaction. Since there is no hydrogen in graphite structure, it is not possible to observe electrophilic substitution. On the other hand this work shows the role of the moisture present on graphite in the functionalization reaction under this condition. Therefore, a reaction mechanism with the participation of the water naturally adsorbed on graphite stabilizing the formed carbocation has been suggested. After the reaction, the functionalized graphite was used as electrode material. Four molecules were used to functionalize graphite: Ferrocene monocarboxylic acid, 4-nitrobenzoyl chloride, 3,5-dinitrobenzoyl chloride and 3,4-dinitrobenzoic acid. To study the optimal conditions of the reaction, the microwave radiation power was varied and the extent of the functionalization on graphite was sensitive to this parameter. Two techniques were used to characterize the materials, cyclic voltammetry and thermal analysis (TG and DTA). IR and Raman data are shown in appendix A. Electrochemical results have shown that the materials functionalized at higher microwave radiation power have higher Faradaic current, but are more resistive. The potential difference between the peaks of the redox process of ferrocene increased with the extent of functionalization. This occurs because an overpotencial is needed to compensate the ionic flux (in order to maintain the electroneutrality) related to the number of species involved. The electrochemical results also indicated that the extent of functionalization of graphite with the nitro compounds was low. The thermal analysis have shown that the functionalization of graphite with ferrocene lead to values between 15% to 20% (m/m) of compound in the material. The materials functionalized at higher microwave radiation power presented higher relative mass in the material. The reaction with the nitro compounds lead to less than 3% (m/m) of compound in the final material. The results of both techniques were coherent about the extent of functionalization. The material functionalized with ferrocene monocarboxylic acid showed the best results, and an explanation for that based on the reaction mechanism is suggested. In order to elucidate the reaction mechanism, some experiments were realized in absent of some reagents. When the reaction were carried out without aluminum chloride or with dried graphite, the reaction has not occurred.

Substâncias contendo clorexidina (CHX) ou associação de antibióticos têm sido pesquisadas como medicações intracanal. Os objetivos do presente estudo foram: Capítulo 1- Caracterizar a resposta do tecido conjuntivo subcutâneo de camundongos à pasta triantibiótica (Trimix), por microscopia óptica convencional e por RT-PCR em tempo real; e Capítulo 2 - Comparar a resposta do tecido conjuntivo subcutâneo de camundongos a medicações intracanal contendo CHX por microscopia óptica convencional. No Capítulo 1, a resposta do tecido conjuntivo subcutâneo de camundongos foi avaliada por meio da implantação de tubos de polietilieno vazios ou contendo uma das substâncias avaliadas: Trimix ou Calen. Como controle adicional, foram utilizados animais que não receberam a implantação dos tubos. Para a avaliação histopatológica, decorridos os períodos experimentais de 7, 21 e 63 dias, os implantes (n=10) contendo Trimix ou Calen foram removidos juntamente com o tecido conjuntivo subcutâneo e a pele adjacente e submetidos ao processamento histotécnico, sendo os cortes corados pelo método de hematoxilina e eosina e picrosírius vermelho. Foram efetuadas análises qualitativa, determinando os parâmetros de resposta biológica e quantitativa, onde foram avaliados o número de células inflamatórias e de vasos, a área e a densidade vascular, além do percentual relativo de colágeno. As reações de RT-PCR em tempo real foram realizadas nos grupos tubo vazio, pasta Calen, Trimix e controle adicional nos períodos experimentais de 7 e 21 dias. Foi realizada a detecção e quantificação das citocinas pró-inflamatórias (IL-1&beta;, TNF-&alpha; e IL- 17) e anti-inflamatória (TGF-&beta;), fator crescimento endotelial vascular (VEGF), fator induzido por hipóxia (HIF-1&alpha;), metaloproteinases (MMP-2 e -9) e inibidores de metaloproteinases (TIMP-1 e - 2). Os resultados foram comparados empregando teste t de Student e ANOVA, seguida do pósteste de Tukey. No Capítulo 2, foi efetuada a comparação da resposta do tecido conjuntivo subcutâneo de camundongos às pastas Calen+CHX a 0,5%, Calen+CHX a 2,0%, ao gel de CHX a 2,0% e à pasta Calen (controle) utilizando metodologia semelhante à empregada para avaliação histopatológica no Capítulo 1. Os resultados obtidos foram analisados por meio da ANOVA, seguida do pós-teste de Tukey. O nível de significancia adotado em todas as análises estatísticas foi de 5%. Com base nos resultados obtidos, pôde-se concluir que: 1) A resposta do tecido conjuntivo subcutâneo de camundongos à pasta Trimix caracterizou-se por reação inflamatória aguda persistente e ausência de reparo no período estudado de 63 dias, o que foi suportado pela maior expressão gênica dos biomarcadores relacionados à resposta inflamatória e angiogênica, comparado à pasta Calen; 2) Quando comparadas as medicações contendo CHX, os resultados evidenciaram que a Calen+CHX a 0,5% exibiu resposta tecidual reparativa, em contraste com a Calen+CHX a 2,0% e o gel de CHX a 2,0% que propiciaram resposta inflamatória persistente, apontando para agressividade destes materiais. Considerando a Calen+CHX a 2,0% e o gel de CHX a 2,0%, este apresentou resposta inflamatória de maior intensidade. Desse modo, o presente estudo fornece indícios que as pastas Trimix, Calen+CHX a 2,0% e o gel de CHX a 2,0% não deveriam ser empregadas como medicação intracanal. / Substances containing chlorhexidine (CHX) or combination of antibiotics have been investigated as intracanal dressings. The aim of this study were: Chapter 1 - To characterize the response of mice subcutaneous connective tissue to triantibiotic paste (Trimix), by conventional optical microscopy and real-time RT-PCR; and Chapter 2 - Compare the response of mice subcutaneous connective tissue to intracanal dressings containing CHX by conventional optical microscopy. In Chapter 1, the response of mice subcutaneous connective tissue was assessed by implantation of polyethylene tubes empty or containing one of the substances evaluated: Trimix or Calen. As additional control, animals that not received implantation of the tubes were used. For histopathological evaluation, after the experimental periods of 7, 21 and 63 days, the implants (n=10) containing Trimix or Calen were removed along with the subcutaneous connective tissue and adjacent skin and subjected to processing histotechnical, and the sections were stained with hematoxylin and eosin or picrosirius red. It was carried out a qualitative analysis, determining the biological parameters and a quantitative response, assessing the number of inflammatory cells and vessels, the area and vascular density, and the relative percentage of collagen. The real-time RT-PCR reactions were performed in the empty tube group, pastes Calen, Trimix and additional control at the experimental periods of 7 and 21 days. The detection and quantification of proinflammatory (IL-1&beta;, TNF-&alpha; and IL-17) and antiinflammatory cytokines (TGF-&beta;), vascular endothelial growth factor (VEGF), hypoxia-induced factor (HIF-1&alpha;), metalloproteinases (MMP-2 and -9) and metalloproteinases inhibitors (TIMP-1 and -2) were performed. The results were compared using Student\'s t test and ANOVA followed by Tukey test. In Chapter 2, it was compared the response of mice subcutaneous connective tissue to Calen+0.5% CHX, Calen+2.0% CHX, 2.0% CHX gel and paste Calen (control) using methodology similar to that one used for histopathologic evaluation in Chapter 1. The results were analyzed by ANOVA followed by Tukey test. The significance level for all statistical analysis was 5%. It was concluded: 1) The response of mice subcutaneous connective tissue to Trimix paste was characterized by persistent acute inflammatory reaction with no repair during the studied period of 63 days, which was supported by the higher gene expression of biomarkers related to inflammation and angiogenesis, compared to Calen paste; 2) The Calen+0.5% CHX showed reparative tissue response, in contrast to Calen+2.0% CHX and 2.0% CHX gel that have led to persistent inflammatory response, indicating aggressiveness of these materials. Considering the Calen+2.0% CHX and CHX 2.0% gel, this induced more intense inflammatory response. Thus, this study provides evidence that the pastes Trimix, Calen+2.0% CHX and 2.0% CHX gel should not be used as intracanal dressing.

O progresso científico e tecnológico das últimas décadas registra um avanço significativo no processo de obtenção da cal, porém, há uma lacuna de conhecimento de base referente à sua ação quando empregada em conjunto com o cimento Portland. O uso da cal nas argamassas mistas de acabamento tem sido associado positivamente apenas à plasticidade no estado fresco e à sua deformabilidade no estado endurecido. Maiores informações são necessárias sobre a ação da cal na evolução das propriedades da argamassa no estado fresco, vinculadas à hidratação do cimento. Este conhecimento é importante para o desenvolvimento de formulações que atendam ao desempenho desejado em diferentes aplicações. O entendimento do mecanismo de hidratação do cimento em presença da cal constitui uma plataforma para estudos de adições minerais ativas ao clínquer, com adição de cal hidratada como fonte externa de cálcio, na produção de novos materiais cimentícios sustentáveis. O estudo em pasta realizado teve como foco a interação cimento-cal visando identificar os fenômenos químicos e físicos relevantes que se sucedem à adição de água ao sistema. Foram caracterizadas as idades iniciais de hidratação do cimento por meio de ensaios de calorimetria de condução, termogravimetria (TG/DTG) e difratometria de raios X em material no estado fluido e em regime consecutivo de coleta de dados. Os experimentos envolveram as proporções 1:1 e 1:2 de cimento Portland tipo CP II E com cales hidratadas tipos CH I e CH III de natureza cálcica e dolomítica, respectivamente. A cal CH I incorpora à mistura elevado teor de hidróxido de cálcio com imediata saturação do meio por íons hidroxila e íons cálcio; a cal CH III incorpora também, em maior quantidade, filler carbonático. Por efeito químico, devido à presença da cal, há alteração da velocidade de hidratação, mas com formação dos produtos de reação característicos da hidratação do cimento. Por efeito físico, o filler carbonático e a fração insolúvel do hidróxido de cálcio da cal, presente no meio saturado, atuam como nucleador para precipitação de fases hidratadas. O efeito combinado desses fenômenos promoveu aceleração da hidratação do cimento Portland, principalmente no período de indução, quando prevalecem as reações de formação de etringita e de aluminatos de cálcio hidratados. / In the last decades, scientific and technological progress has shown a significant advance in the process of obtaining lime; however, there is gap knowledge with relation to its action when employed together with Portland cement. The use of lime in finishing mix mortars has only been positively associated to the fresh state plasticity and ability to deformation in the hardened state. It is necessary to collect data about the role of lime in the gradual development of the properties of mortars in the fresh state, linked to cement hydration. Such knowledge is important to develop formulas which can meet the required performance in different uses. The current demand of sustainable materials has favored the addition of minerals to the composition of Portland cement, and hydrated lime as an extern source of calcium, is a feasible alternative to the composition of byproducts and mixtures to be used as alternative binders. This research focused the cement-lime interaction aiming at identifying relevant chemical and physical phenomena which succeed the addition of water to the system. The paste study characterized the early ages of hydration by means of isothermal calorimetric, thermogravimetric, X-ray diffraction in material in the fluid state analysis collecting data in a consecutive basis. The experiments were carried out by using two proportions of Portland cement type CP II E with hydrated lime types CH I and CH III, calcic and dolomitc, respectively. By adding lime CH I to the cement-water system, calcium hydroxide is abundantly incorporated, with immediate saturation by means of hydroxide ions and calcium ions. The addition of lime CH III, also incorporates, in greater amount, finely ground limestone. Due to chemical effect because of the presence of lime, there is alteration in speed of hydration, forming products characteristics to the cement hydration process. Due to physical effect, the filler and the lime insoluble fraction of calcium hydroxide, present in the saturated environment, work as facilitators to the precipitation of the hydrated phases. The combined effect of these two phenomena accelerated hydration of Portland cement, mainly in the induction period, when ettringite and hydrated calcium aluminates formation reactions prevail. The advancement made in terms of knowledge permits to broaden comprehension on the behavior of mixtures in early stages, when hardening and consolidation processes are applied to mortars and help rheologic studies which involve their application. The understanding of the hydration mechanism in the presence of lime sets a base to study additions of active minerals to the clinker and produce new sustainable cementious compounds.

Sabemos que em placas de circuito impresso montadas com tecnologia SMD Surface Mount Device podem ocorrer problemas com a migração eletroquímica. O fenômeno aparece principalmente porque os novos encapsulamentos possuem terminais com espaçamentos muito próximos. A migração eletroquímica pode tornar-se um potencial problema no processo de soldagem eletrônica quando é utilizado a tecnologia Lead Free na montagem das placas. O processo de migração eletroquímica ocorre quando temos metal, isolante e metal, em ambiente de alta umidade e sobre polarização elétrica, o metal deixa a posição inicial em forma de íon e se redeposita sobre o isolante. Em uma placa de circuito impresso, dois terminais adjacentes podem tornar-se eletrodos, dessa forma as dendritas crescem do cátodo para o ânodo. Podem aparecer diferentes morfologias com diferentes elementos envolvidos no processo de migração, dependendo da composição da pasta de solda ou acabamento da placa de circuito impresso. Uma estrutura do tipo pente comb feita sobre laminado FR4 foi utilizada nos experimentos. A distância entre as trilhas foram de 102 e 254 mícrons para simular uma distancia real dos terminais dos dispositivos. Os fatores considerados durante os experimentos foram: A distancia entre os terminais na estrutura (102 ou 254 mícrons), tensão aplicada (2 ou 3 V). Foi observado que a pasta de solda e o acabamento final não influenciam no processo de migração eletroquímica. O Estanho foi o principal metal que migrou. Todos os resultados obtidos nesse estudo concordam com a literatura. / It is well known that in printed circuits boards assembled by SMT technology may occur Electrochemical migration (ECM). This phenomenon appears mainly because the new packaging has the terminals very close. Also the Electrochemical migration may become a potential reliability problem in electronic soldering when lead free technology is used in soldering electronic devices. Electrochemical migration is an electrochemical process where metal on an insulating material, in a humid environment and under an applied electric field, leaves its initial location in ionic form and redeposit. In a PCB two adjacents terminal may behave as electrodes so the dendrites grow from cathode to anode. It can show different morphologies with the different migration elements involved depending on the solder paste composition or PCB surface finishing. A structure with a comb shape printed on FR4 substrate was used in the experiments. The distance between the fingers in the structure was 102 or 254 microns, in order to simulate a real distance between dispositive terminals. The factors considered during the experiments were surface finishing (ENIG or HASL), solder paste composition, distance between terminals (102 or 254 microns) and applied voltage (2 or 3 V). It was observed that the solder paste and the surface finishing dont influence the ECM process. Tin was the main metal that migrates. All the results obtained in these study agrees with the literature.

Substâncias contendo clorexidina (CHX) ou associação de antibióticos têm sido pesquisadas como medicações intracanal. Os objetivos do presente estudo foram: Capítulo 1- Caracterizar a resposta do tecido conjuntivo subcutâneo de camundongos à pasta triantibiótica (Trimix), por microscopia óptica convencional e por RT-PCR em tempo real; e Capítulo 2 - Comparar a resposta do tecido conjuntivo subcutâneo de camundongos a medicações intracanal contendo CHX por microscopia óptica convencional. No Capítulo 1, a resposta do tecido conjuntivo subcutâneo de camundongos foi avaliada por meio da implantação de tubos de polietilieno vazios ou contendo uma das substâncias avaliadas: Trimix ou Calen. Como controle adicional, foram utilizados animais que não receberam a implantação dos tubos. Para a avaliação histopatológica, decorridos os períodos experimentais de 7, 21 e 63 dias, os implantes (n=10) contendo Trimix ou Calen foram removidos juntamente com o tecido conjuntivo subcutâneo e a pele adjacente e submetidos ao processamento histotécnico, sendo os cortes corados pelo método de hematoxilina e eosina e picrosírius vermelho. Foram efetuadas análises qualitativa, determinando os parâmetros de resposta biológica e quantitativa, onde foram avaliados o número de células inflamatórias e de vasos, a área e a densidade vascular, além do percentual relativo de colágeno. As reações de RT-PCR em tempo real foram realizadas nos grupos tubo vazio, pasta Calen, Trimix e controle adicional nos períodos experimentais de 7 e 21 dias. Foi realizada a detecção e quantificação das citocinas pró-inflamatórias (IL-1&beta;, TNF-&alpha; e IL- 17) e anti-inflamatória (TGF-&beta;), fator crescimento endotelial vascular (VEGF), fator induzido por hipóxia (HIF-1&alpha;), metaloproteinases (MMP-2 e -9) e inibidores de metaloproteinases (TIMP-1 e - 2). Os resultados foram comparados empregando teste t de Student e ANOVA, seguida do pósteste de Tukey. No Capítulo 2, foi efetuada a comparação da resposta do tecido conjuntivo subcutâneo de camundongos às pastas Calen+CHX a 0,5%, Calen+CHX a 2,0%, ao gel de CHX a 2,0% e à pasta Calen (controle) utilizando metodologia semelhante à empregada para avaliação histopatológica no Capítulo 1. Os resultados obtidos foram analisados por meio da ANOVA, seguida do pós-teste de Tukey. O nível de significancia adotado em todas as análises estatísticas foi de 5%. Com base nos resultados obtidos, pôde-se concluir que: 1) A resposta do tecido conjuntivo subcutâneo de camundongos à pasta Trimix caracterizou-se por reação inflamatória aguda persistente e ausência de reparo no período estudado de 63 dias, o que foi suportado pela maior expressão gênica dos biomarcadores relacionados à resposta inflamatória e angiogênica, comparado à pasta Calen; 2) Quando comparadas as medicações contendo CHX, os resultados evidenciaram que a Calen+CHX a 0,5% exibiu resposta tecidual reparativa, em contraste com a Calen+CHX a 2,0% e o gel de CHX a 2,0% que propiciaram resposta inflamatória persistente, apontando para agressividade destes materiais. Considerando a Calen+CHX a 2,0% e o gel de CHX a 2,0%, este apresentou resposta inflamatória de maior intensidade. Desse modo, o presente estudo fornece indícios que as pastas Trimix, Calen+CHX a 2,0% e o gel de CHX a 2,0% não deveriam ser empregadas como medicação intracanal. / Substances containing chlorhexidine (CHX) or combination of antibiotics have been investigated as intracanal dressings. The aim of this study were: Chapter 1 - To characterize the response of mice subcutaneous connective tissue to triantibiotic paste (Trimix), by conventional optical microscopy and real-time RT-PCR; and Chapter 2 - Compare the response of mice subcutaneous connective tissue to intracanal dressings containing CHX by conventional optical microscopy. In Chapter 1, the response of mice subcutaneous connective tissue was assessed by implantation of polyethylene tubes empty or containing one of the substances evaluated: Trimix or Calen. As additional control, animals that not received implantation of the tubes were used. For histopathological evaluation, after the experimental periods of 7, 21 and 63 days, the implants (n=10) containing Trimix or Calen were removed along with the subcutaneous connective tissue and adjacent skin and subjected to processing histotechnical, and the sections were stained with hematoxylin and eosin or picrosirius red. It was carried out a qualitative analysis, determining the biological parameters and a quantitative response, assessing the number of inflammatory cells and vessels, the area and vascular density, and the relative percentage of collagen. The real-time RT-PCR reactions were performed in the empty tube group, pastes Calen, Trimix and additional control at the experimental periods of 7 and 21 days. The detection and quantification of proinflammatory (IL-1&beta;, TNF-&alpha; and IL-17) and antiinflammatory cytokines (TGF-&beta;), vascular endothelial growth factor (VEGF), hypoxia-induced factor (HIF-1&alpha;), metalloproteinases (MMP-2 and -9) and metalloproteinases inhibitors (TIMP-1 and -2) were performed. The results were compared using Student\'s t test and ANOVA followed by Tukey test. In Chapter 2, it was compared the response of mice subcutaneous connective tissue to Calen+0.5% CHX, Calen+2.0% CHX, 2.0% CHX gel and paste Calen (control) using methodology similar to that one used for histopathologic evaluation in Chapter 1. The results were analyzed by ANOVA followed by Tukey test. The significance level for all statistical analysis was 5%. It was concluded: 1) The response of mice subcutaneous connective tissue to Trimix paste was characterized by persistent acute inflammatory reaction with no repair during the studied period of 63 days, which was supported by the higher gene expression of biomarkers related to inflammation and angiogenesis, compared to Calen paste; 2) The Calen+0.5% CHX showed reparative tissue response, in contrast to Calen+2.0% CHX and 2.0% CHX gel that have led to persistent inflammatory response, indicating aggressiveness of these materials. Considering the Calen+2.0% CHX and CHX 2.0% gel, this induced more intense inflammatory response. Thus, this study provides evidence that the pastes Trimix, Calen+2.0% CHX and 2.0% CHX gel should not be used as intracanal dressing.

Current design of cemented paste backfill (CPB) barricades tends to be of unknown conservativeness due to limited understanding of their behaviour. Previous work done to characterize barricade response has not accounted for the effects of the surrounding rock stiffness, which can have significant impact on the development of axial forces which enhance capacity via compressive membrane action. Parametric analyses were performed with the finite element analysis program Augustus-2 to determine the effects of various material and geometric properties on barricade capacity. Equations based on Timoshenko and Boussinesq solutions were developed to model rock stiffness effects based on boundary material properties. An iterative simulation process was used to account for secondary moment effects as a proof of concept. It was found that, for a range of typical rock types, barricade capacity varied significantly. The commonly made design assumption of a fully rigid boundary resulted in unconservative overpredictions of strength.

Current design of cemented paste backfill (CPB) barricades tends to be of unknown conservativeness due to limited understanding of their behaviour. Previous work done to characterize barricade response has not accounted for the effects of the surrounding rock stiffness, which can have significant impact on the development of axial forces which enhance capacity via compressive membrane action. Parametric analyses were performed with the finite element analysis program Augustus-2 to determine the effects of various material and geometric properties on barricade capacity. Equations based on Timoshenko and Boussinesq solutions were developed to model rock stiffness effects based on boundary material properties. An iterative simulation process was used to account for secondary moment effects as a proof of concept. It was found that, for a range of typical rock types, barricade capacity varied significantly. The commonly made design assumption of a fully rigid boundary resulted in unconservative overpredictions of strength.

The complex interaction between cement and chemical/mineral admixtures in concrete mixtures sometimes leads to unpredictable concrete performance in the field which is generally defined as concrete incompatibilities. Cement paste rheology measurements instead of traditional workability tests (i.e., slump cone test) can have great potential in detecting those incompatibilities in concrete before the concrete is placed, which can, in turn, avoid related workability problems and setting time as well as heat evolution abnormalities. The objectives of the present study were to examine the applicability of the dynamic shear rheometer (DSR) to measure cement paste rheology, and to identify cement and mineral/chemical admixture incompatibilities, based on the determined rheological parameters. The DSR was modified and optimized for cement paste rheology measurements. Two different modes of operations (i.e., static and dynamic methods) with the modified DSR were investigated to measure representative rheological parameters as well as to identify cement and chemical/mineral admixture incompatibility. The conventional plastic viscosity and yield stress are measured in static mode and storage modulus curve, as a function of time, is measured in dynamic mode. The rate of change of plastic viscosity (RPV) as another static rheological parameter and the modeled magnitude parameter ?, from the dynamic rheological method, showed great potentialities as acceptance criteria to identify incompatible mixtures. The heat of hydration data from isothermal conduction calorimeter tests and setting time results for the studied mixtures have strongly supported the rheology based observations as supporting tools. Based on the main tests results, the acceptance criteria were set up using the rheological parameters in accordance with heat of hydration data. This will ultimately help material suppliers, concrete producers, and other users to detect problematic combinations of concrete ingredients before a given concrete mixture is placed.