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When high strength aluminum alloys are subjected to liquid metals, physical and chemical reactions ensue resulting in what is known as liquid metal embrittlement (LME). A subset of environmentally-assisted cracking, LME is exhibited when a liquid metal, e.g. Hg or Ga, comes into intimate contact with a solid metal having significant susceptibility. As mechanical loads are applied, the interaction between the two metals results in a reduction in the flow properties of the solid metal. Several theories have been proposed to identify the underlying microstructural failure mechanism; however, none have been widely accepted, as failures can typically incorporate features common to several failure theories. In an effort to confirm, extend or replace the physically-based theories, fracture mechanics experiments on Al 7075-T651 in liquid mercury have been conducted. Experiments were conducted in a custom environmental chamber capable of exposing specimens to liquid environments while applying a mechanical load. Through both plane-strain fracture and stress intensity factor-dependent (SIF) tests, fracture toughness values along with incubation periods were analyzed and provided data for a load-based theory of LME. These mechanical test data, along with metallographic analysis, show that the phenomena of LME is both strongly time- and SIF-dependent.

The objective of my study was to analyse the influence of selected factors in relation to somatic cell counts (SCC) in bulk milk samples of raw cow´s milk. Milk samples were tested in eight cowsheds with different technology of breeding and milking for a period of three years. The SCC values were determined by the Fluoro-opto-electronic method using the apparatus Fossomatic. A significant factor influencing the SCC was the season. The highest average values of the SCC were found in the summer months. The lowest average values of the SCC were determined in the loose bedded cubicle housing (250.103.ml-1), while the difference in the SCC compared to the loose bedding-free slatted floor housing (SCC average 317.103.ml-1) was highly statistically significant (p < 0,001). In the tie stall with bedding was the SCC average 292.103.ml-1. A highly statistically significant difference in the SCC (p < 0,001) was also demonstrated between breeds in the milking parlour (SCC average 265.103.ml-1) and breeds in the milking stall in the pipeline systems (SCC average 292.103.ml-1). It also showed a statistically highly significant difference in the SCC (p < 0,001) between breeds dominated by the Holstein breed cows (SCC average 285.103.ml-1) and breeds with breed prevalence of the Czech Fleckvieh cows (SCC average 265.103.ml-1). The level of yield was also affected by the SCC. There was no statistically significant difference among the farms using grazing and breeding without any possibility of keeping cows on pasture.

Les agrégats de molécules d'eau constituent une classe d'espèces chimiques importante du fait de leur rôle central dans de nombreux processus physico-chimiques et biologiques terrestres, en particulier, les processus atmosphériques. Leurs propriétés physiques et chimiques sont particulièrement sensibles aux effets de taille et aux effets de température, ce qui les rend particulièrement difficile à caractériser expérimentalement. Ainsi, mes travaux de thèse ont porté sur l'étude théorique des propriétés structurales, dynamiques et thermodynamiques ainsi que sur la réactivité de divers agrégats de molécules d'eau avec pour objectif de mettre en place des outils de modélisation adaptés, permettant une description plus fine de ces systèmes. Pour cela, nous avons utilisé des approches de dynamique moléculaire de type "parallel-tempering" qui ont été couplées avec des calculs d'énergie et de gradient réalisés par la méthode Self-Consistent-Charge Density-Functional based Tight-Binding (SCC-DFTB). Trois grands volets ont été abordés au cours de ces travaux. Dans la première partie, l'analyse détaillée des structures des agrégats d'eau (H2O)nSO24- et (H2O)nH2SO4 avec n=1-20 est présentée. Nous avons mis en évidence l'influence de la nature de l'impureté soufrée sur le réseau de liaisons hydrogène de ces agrégats. La deuxième partie de cette thèse porte sur l'étude de la transition de phase "solide-liquide" dans divers agrégats de molécules d'eau. En plus des agrégats soufrés évoqués ci-dessus, nous avons également étudié des agrégats d'eau protonés contenant de 19 à 23 molécules d'eau. Pour mieux comprendre le mécanisme de transition de phase, nous avons considéré divers changements structuraux associés à la transition tels que l'évolution des distributions d'angles intermoléculaires et l'évolution du nombre de cycles de molécules dans l'agrégat. Nous avons également caractérisé la transition de phase au travers d'indicateurs dynamiques tels que la fréquence de transfert du proton en excès. La dernière partie de cette thèse est consacrée à l'étude de l'influence de petits agrégats d'eau (allant de 1 à 10 molécules d'eau) sur la réaction de recombinaison entre l'atome H et la molécule CO. Cette réaction est la première étape de formation des molécules organiques oxygénées simples dans le milieu interstellaire. Elle présente donc un intérêt particulier. Grâce à l'analyse de dynamiques collisionnelles entre H et CO ainsi qu'au calcul de sections efficaces de réaction, nous avons montré que la présence des molécules d'eau joue un rôle important dans le processus de formation du radical HCO. / Water clusters constitute an important class of chemical species due to their central role in many physico-chemical and biological processes, in particular, atmospheric processes. Their physical and chemical properties are particularly sensitive to size and finite-temperature effects, which makes them particularly difficult to characterize experimentally. This thesis focused on the theoretical investigation of the structural, dynamical and thermodynamical properties as well as on the reactivity of various water clusters with the aim to implement appropriate modeling tools to enable a more detailed description of these systems. To do so, we used the paralleltempering molecular dynamics approach that was coupled with calculations of energies and gradients carried out by the Self-Consistent-Charge Density-Functional based Tight-Binding (SCC-DFTB) method.Three main areas were addressed during the work. In the first part, a detailed analysis of the structure of water clusters (H2O)nSO24- and (H2O)nH2SO4 with n=1-20 is performed. This study highlights the influence of the nature of the sulfur impurity on the hydrogen bond network of these species.The second part of this thesis focuses on the study of the "solid-liquid" phase transition in various water clusters. In addition to the sulfur-containing water clusters mentioned above, we also investigated protonated water clusters containing from 19 to 23 water molecules. To better understand the phase transition mechanism, we considered various structural changes associated with the transition, such as the evolution of the distributions of intermolecular angles and the evolution of the number of molecular rings in the cluster. We also characterized the phase transition through dynamical indicators such as the crossover frequency of the excess proton. The last part of this thesis is devoted to the study of the influence of small water clusters (from 1 to 10 water molecules) on the recombination reaction between the H atom and the CO molecule. This reaction is the first step in the formation of simple oxygenated organic molecules in the interstellar medium. It is therefore of particular interest. Due to the analysis of collisional dynamics between H and CO and the calculation of effective reaction cross sections we showed that the presence of water molecules plays an important role in the HCO radical formation.

<p>With the advent of Self-Compacting Concrete (SCC) that flows freely, under the soleinfluence of gravity, the wish for hassle-free and predictable castings even in complexcases, spurged the simulation of concrete flow as a means to model and predictconcrete workability. To achieve complete and reliable form filling with smoothsurfaces of the concrete, the reinforced formwork geometry must be compatible withthe rheology of the fresh SCC. Predicting flow behavior in the formwork and linkingthe required rheological parameters to flow tests performed on the site will ensurean optimization of the casting process.In this thesis, numerical simulation of concrete flow is investigated, using both discreteas well as continuous approaches.The discrete particle model here serves as a means to simulate details and phenomenaconcerning aggregates modeled as individual objects. The here presented cases aresimulated with spherical particles. However, it is possible to make use of nonsphericalparticles as well. Aggregate surface roughness, size and aspect ratio maybe modeles by particle friction, size and clumping several spheres into forming thedesired particle shape.The continuous approach has been used to simulate large volumes of concrete. Theconcrete is modeled as a homogeneous material, particular effects of aggregates,such as blocking or segregation are not accounted for. Good correspondence wasachieved with a Bingham material model used to simulate concrete laboratory tests(e.g. slump flow, L-box) and form filling. Flow of concrete in a particularly congestedsection of a double-tee slab as well as two lifts of a multi-layered full scale wall castingwere simulated sucessfully.A large scale quantitative analysis is performed rather smoothly with the continuousapproach. Smaller scale details and phenomena are better captured qualitativelywith the discrete particle approach. As computer speed and capacity constantlyevolves, simulation detail and sample volume will be allowed to increase.A future merging of the homogeneous fluid model with the particle approach to formparticles in the fluid will feature the flow of concrete as the physical suspension thatit represents. One single ellipsoidal particle falling in a Newtonian fluid was studiedas a first step.</p> / <p>Med uppkomsten av självkompakterande betong (SKB) och dess möjligheter att flyta ut under inverkan av endast gravitation uppstod ett behov av att kunna förutsäga och kontrollera även mer komplicerade gjutningar. Numerisk simulering av SKBs flöde kan kommma att utgöra ett kraftfullt verktyg för att optimera gjutprocessen, ge möjlighet att förutsäga nödbvändig arbetbarhet och säkerställa kompatibilitet mellan den armerade formen och betongens reologi. I föreliggande avhandling undersöks betongens flöde med både diskreta och kontinuumbaserade simuleringsmetoder. Den diskreta partikelmodellen används för att simulera detaljer och fenomen hos t.ex. ballast i betong. I de här presenterade simuleringarna används sfäriska partiklar, men det är även möjligt att skapa ballastkorn av olika form. Ballastens ytråhet och storlek kan modelleras med parametrar för friktion och storlek medan sammanfogning av ett flertal partiklar kan ge ekvivalent form. Den kontinuumbaserade ansatsen används för att simulera större flödesmängder. Betongen modelleras som ett homogent material, eventuella effekter av ballastens inverkan, till exempel blockering eller separation, ingår ej. God överensstämmelse har uppnåtts med Binghams materialmodell som applicerats på några av SKBs provningsmetoder (bl a flytsättmått och L-låda) liksom även för större gjutningar. Formfyllnad av en hårt armerad sektion av ett STT-element, liksom två pumpade betongleveranser till en hög vägg, har framgångsrikt simulerats. En kvantitativ övergripande analys av betongflödet i formen kan göras med den kontinuumbaserade ansatsen för att upptäcka zoner med eventuella svårigheter. En högupplöst detaljstudie kompletterar sedan analysen på valda delar av och kring dessa zoner för att fånga partikelfenomen kvalitativt med hjälv av den diskreta modellen. Då datorkapaciteten ökar kommer även större volymer med högre detaljrikedom att kunna simuleras. En framtida modell simulerar med stor sannolikhet partiklar i flöde, vilket till fullo kan fånga betongens egenskaper som suspension. Som ett första steg på vägen har en fallande ellipsoid i en newtonsk vätska simulerats.</p>

Feline oral squamous cell carcinomas (FOSCCs) are locally aggressive tumours and a common cause of mortality and morbidity. Current treatment options are rarely successful and animals are frequently euthanised upon diagnosis due to their grave prognosis. Epidermal Growth Factor Receptor (EGFR) is a tyrosine kinase receptor which is frequently dysregulated in SCC of the head and neck (HNSCC) in man. Recent advances in human medicine have identified EGFR as a therapeutic target in HNSCC. In this study the role of EGFR in FOSCC was investigated. Sixty seven biopsy samples were immunohistochemically labelled for EGFR and Ki67, a proliferation marker. The tyrosine kinase region of feline EGFR was cloned and sequenced, and six small interfering RNAs (siRNAs) targeting the tyrosine kinase region were developed. The most effective siRNA as well as an EGFR specific tyrosine kinase inhibitor, gefitinib, was then used on a feline SCC cell line (SCCF1), and the effect of EGFR targeting alone, or in combination with irradiation, on the cell line was determined. The majority of the biopsy samples were labelled positively for EGFR and Ki67, and high proliferation corresponded with poor prognosis. The siRNA caused reduction in EGFR mRNA by Real-Time Polymerase Chain Reaction and protein levels as assessed by western blot analysis. Reduced cell proliferation and migration were also observed by proliferation assays and scratch assays respectively. Combining EGFR knockdown with irradiation caused an additive effect on the ability of the cell line to form colonies. These results support the role of EGFR as a potential therapeutic target in FOSCCs.

A doença da inflamação da glândula mamária, também conhecida como mastite, tem como uma das características o aumento de células somáticas no leite de quartos afetados. Entre as bactérias predominantes causadoras de mastites, destacam-se Staphylococcus spp. e Streptococcus spp. Vários estudos sugerem que estes agentes são tipicamente transmitidos de uma vaca para outra durante o momento da ordenha. A aplicação de programas de boas práticas de ordenha (BPO) permitem o controle da mastite pela eliminação de infecções detectadas no rebanho, prevenção de riscos e adequadas condições produtivas e sanitárias. A interação contínua entre produtores e técnicos tem se confirmado como ferramenta importante nos programas de treinamento, favorecendo o compartilhamento de experiências. Sendo assim, o presente estudo teve como objetivo avaliar a influência da capacitação técnica em BPO na qualidade higiênica do leite, mediante o monitoramento das práticas de ordenha implementadas, análises de componentes químicos e microbiológicos, incluindo a identificação de Staphylococcus spp. e Streptococcus spp., em propriedades leiteiras do estado de São Paulo. Na fase final do estudo foi observado que 84% dos itens de BPO avaliados estavam sendo usados com capacitação técnica, incluindo modificações de infraestrutura e controle da qualidade da fonte de água. O sucesso da aplicação de programas de controle da qualidade requerem o comprometimento dos produtores de leite. Entre as BPO que não foram adotadas, destacam-se o uso de luvas durante a ordenha e sanitizante na limpeza dos equipamentos, práticas que poderiam diminuir a transmissão dos patógenos contagiosos entre os animais. Embora as análises microbiológicas e identificação dos patógenos dos diferentes pontos de coleta tenham apresentado resultados variáveis ao longo do estudo, elas constituíram uma ferramenta importante durante o processo de capacitação técnica. / The mammary gland disease, also known as mastitis, has as characteristic the increase of somatic cells in milk from affected udder. Among the predominant bacteria causing mastitis, Staphylococcus spp. and Streptococcus spp are highlighted. Several studies suggest that these agents are typically transmitted from one cow to another during the milking. The application of programs on good milking practices (GMP) allows the control of mastitis through the elimination of infections detected in the herd, prevention of risks and proper productive and sanitary conditions. The continuous interaction between farmers and trainers has been confirmed as an important tool on training programs, supporting sharing experiences. Therefore, the present study aimed to evaluate the influence of GMP training on hygienic quality of milk, by monitoring milking practices implemented, chemical and microbiological analyzes, including the identification of Staphylococcus spp. and Streptococcus spp. in dairy farms from Sao Paulo state. In the final phase of this study it was demonstrated that 84% of the BPO evaluated items were being used with training including infrastructure modifications and quality control of the water source. The success of the implementation of quality control programs requires the commitment of dairy farmers. The GMP not adopted included the use of gloves during milking and sanitizers on equipment cleaning, practices that could reduce the transmission of contagious pathogens among animals. Although the microbiological analyses of the pathogens in different points on the milking management were inconstant during the study, they constitute an important tool during the training process.

O elevado custo dos tratamentos tradicionais da mastite bovina, associado à redução de produção e inviabilidade de tratamento das mastites subclínicas durante a lactação, bem como a exigência cada vez mais rigorosa da ausência de resíduos de antimicrobianos por parte de instituições nacionais e internacionais, impulsiona o desenvolvimento de novas alternativas terapêuticas que visem minimizar o impacto das medidas tradicionais de tratamento. A homeopatia surge como importante alternativa, sendo aceita nacional e internacionalmente. O objetivo do trabalho foi avaliar o tratamento homeopático com Phytolacca decandra 30CH durante a lactação de vacas com mastite subclínica, utilizando parâmetros de qualidade do leite como Califórnia Mastitis Test (CMT), contagem de células somáticas (CCS) totais, porcentagens de polimorfonucleares (PMN) e de mononucleares (MN), teores de proteína, lactose, gordura, sólidos totais (ST) e extrato seco desengordurado (ESD), além da mensuração da produção leiteira. Foram selecionadas 26 vacas, CMT 2+ e 3+ sem sinais de mastite clínica, entre o terceiro e sexto mês de lactação, pluríparas e divididas em dois grupos, um com tratamentos medicamentosos mensais e outro com tratamentos quinzenais. Mensalmente foram colhidas duas amostras de leite de cada glândula mamária (teto) que apresentava mastite subclínica. Uma das amostras foi utilizada para CCS e análise dos componentes do leite, e a outra para identificação microbiológica. Nos grupos tratados, foi administrado o medicamento homeopático Phytolaca decandra 30CH diluído em água e aspergido nas mucosas oro-nasais e vaginais, enquanto que nos grupos denominados controle foi administrado placebo da mesma maneira. A pesagem da produção láctea de ambos os grupos foi realizada quinzenalmente até o final do experimento. Verificou-se então que não houve diferença significativa entre a produção láctea, CCS e a presença de microrganismos na secreção láctea das glândulas quando comparadas antes e depois do tratamento homeopático, dentro de cada grupo, bem como quando comparados os grupos entre si. As medianas de CMT e porcentagens de PMN foram compatíveis com infecções mamárias agudas, embora os animais tenham sido diagnosticados como portadores de mastites crônicas e em nenhum momento desenvolveram sinais clínicos. / The high cost of traditional treatments of bovine mastitis, with the reduction of production and impracticable treatment of subclinical mastitis during lactation, as well as the requirement of an increased demand for absence of antimicrobial agents residues by national and international institutions, drives the development of new therapeutic alternatives in order to minimizing the impact of traditional treatment measures. The homeopathy appears as an important alternative, accepted domestically and internationally. The objective of this work was to evaluate homeopathic treatment with Phytolacca decandra 30CH during the lactation of cows with subclinical mastitis, using some milk quality parameters as California Mastitis Test (CMT), total somatic cell count (SCC), percentages of polymorphonuclear (PMN) and mononuclear (MN) cells, levels of protein, lactose, fat, total solids and dry defatted matter, in addition to the measurement of milk production. Twenty-six cows were selected with CMT 2 + and 3 + without any signs of clinical mastitis, between the third and sixth month of lactation, pluriparous and they were divided into two groups, with monthly or biweekly drug treatments. Monthly were collected two milk samples from each mammary gland (teat) that presented subclinical mastitis. One of the samples was used for analysis of SCC and milk components, and the other one for microbiological identification. In the treated groups, was given the homeopathic medicine Phytolaca decandra 30CH diluted in water and sprayed in the oral-nasal and vaginal mucosa, while to the control group was given placebo following the same method. The weighing of the milk production for both groups was performed fortnightly until the end of the experiment. There was no significant difference between milk production, SCC and the presence of microorganisms in milk gland secretion compared before and after homeopathic treatment, within each group as well as comparing the groups together. The medians of CMT and percentages of PMN were compatible with acute mammary infection, in spite of they have been diagnosed as carriers of chronic mastitis, and at any time no clinical signs have been developed.

A doença da inflamação da glândula mamária, também conhecida como mastite, tem como uma das características o aumento de células somáticas no leite de quartos afetados. Entre as bactérias predominantes causadoras de mastites, destacam-se Staphylococcus spp. e Streptococcus spp. Vários estudos sugerem que estes agentes são tipicamente transmitidos de uma vaca para outra durante o momento da ordenha. A aplicação de programas de boas práticas de ordenha (BPO) permitem o controle da mastite pela eliminação de infecções detectadas no rebanho, prevenção de riscos e adequadas condições produtivas e sanitárias. A interação contínua entre produtores e técnicos tem se confirmado como ferramenta importante nos programas de treinamento, favorecendo o compartilhamento de experiências. Sendo assim, o presente estudo teve como objetivo avaliar a influência da capacitação técnica em BPO na qualidade higiênica do leite, mediante o monitoramento das práticas de ordenha implementadas, análises de componentes químicos e microbiológicos, incluindo a identificação de Staphylococcus spp. e Streptococcus spp., em propriedades leiteiras do estado de São Paulo. Na fase final do estudo foi observado que 84% dos itens de BPO avaliados estavam sendo usados com capacitação técnica, incluindo modificações de infraestrutura e controle da qualidade da fonte de água. O sucesso da aplicação de programas de controle da qualidade requerem o comprometimento dos produtores de leite. Entre as BPO que não foram adotadas, destacam-se o uso de luvas durante a ordenha e sanitizante na limpeza dos equipamentos, práticas que poderiam diminuir a transmissão dos patógenos contagiosos entre os animais. Embora as análises microbiológicas e identificação dos patógenos dos diferentes pontos de coleta tenham apresentado resultados variáveis ao longo do estudo, elas constituíram uma ferramenta importante durante o processo de capacitação técnica. / The mammary gland disease, also known as mastitis, has as characteristic the increase of somatic cells in milk from affected udder. Among the predominant bacteria causing mastitis, Staphylococcus spp. and Streptococcus spp are highlighted. Several studies suggest that these agents are typically transmitted from one cow to another during the milking. The application of programs on good milking practices (GMP) allows the control of mastitis through the elimination of infections detected in the herd, prevention of risks and proper productive and sanitary conditions. The continuous interaction between farmers and trainers has been confirmed as an important tool on training programs, supporting sharing experiences. Therefore, the present study aimed to evaluate the influence of GMP training on hygienic quality of milk, by monitoring milking practices implemented, chemical and microbiological analyzes, including the identification of Staphylococcus spp. and Streptococcus spp. in dairy farms from Sao Paulo state. In the final phase of this study it was demonstrated that 84% of the BPO evaluated items were being used with training including infrastructure modifications and quality control of the water source. The success of the implementation of quality control programs requires the commitment of dairy farmers. The GMP not adopted included the use of gloves during milking and sanitizers on equipment cleaning, practices that could reduce the transmission of contagious pathogens among animals. Although the microbiological analyses of the pathogens in different points on the milking management were inconstant during the study, they constitute an important tool during the training process.

Apesar da legislação governamental, dos programas de pagamento por qualidade dos laticínios e do maior consumo de antibióticos, na última década mais de 45% dos rebanhos leiteiros no Brasil tem apresentado CCS acima de 400.000, sem que este valor venha se reduzindo. Existem, no entanto, dentro de uma população submetida às mesmas condições, rebanhos com alta e com baixa CCS. Cabe, então, perguntar por que isto acontece. Dado que a mastite, causadora da alta CCS, é uma doença multifatorial, objetivou-se, neste trabalho, verificar as diferenças entre as propriedades com alta e com baixa CCS e o impacto do homem, tanto o produtor como o ordenhador, sobre a CCS do rebanho. Para isto foram aplicados questionários estruturados e listas de verificação em 68 fazendas participantes de um mesmo programa de pagamento por qualidade e da mesma região. Os rebanhos foram agrupados em fazendas com alta CCS, CCS > 700 mil/mL; e fazendas com baixa CCS, CCS < 250 mil/mL. Os resultados indicam que o homem é o principal diferencial entre os rebanhos. Que tanto o produtor como o ordenhador influencia a CCS do rebanho, sendo que as variáveis que melhor explicam a probabilidade de uma fazenda apresentar baixa CCS são a atitude do produtor e o comportamento do ordenhador com relação à mastite. O comportamento do ordenhador, por sua vez, depende em primeiro lugar dos meios que dispõe para fazer o trabalho e, em segundo lugar, da sua atitude. Portanto, para que se melhore a qualidade do leite, devem ser tomadas medidas direcionadas a modificar a atitude e o comportamento do homem frente à mastite. / Despite the government legislation, of the industry´s programs for milk quality based payment, and the increased use of antibiotics, during the last decade more than 45% of the Brazilian dairy farms have presented SCC over 400.000, and the value does not diminish. Notwithstanding, within the same population and under the same conditions, there are herds of low and high SCC. Then, it is necessary to ask why is this happening. Mastitis is the cause of the high SCC, and mastitis is a multifactorial disease, therefore, the purpose of this research was to find out the differences between the properties with high and low SCC, and find out how the producer and the milker impact the SCC of the herd. For that purpose, structured questionnaires and checklists were applied in 68 farms, which were participating of the same quality-based payment program and were located in the same region. The herds were grouped in cases: farms with high SCC, SCC > 700.000, and controls: herds with low SCC, SCC < 250.000. The results suggest that the man is the main differential between farms. That the producer and the milker impact the SCC of the herd, and that the variables that better explain the chance of a farm to present low SCC, are the producer´s attitude and the milker\'s behavior toward mastitis. The results also showed that the milker\'s behavior depends mainly of the means and secondly, of his attitude. Therefore, to improve the milk quality, must be taken measures to modify the attitude and behavior of the man.