Las nanopartículas (NPs) de metales nobles presentan gran interés tanto por sus propiedades básicas como por la amplia variedad de aplicaciones en las que se utilizan activamente. Para obtener NPs estables y evitar su aglomeración, es necesario utilizaragentes estabilizantes durante la síntesis. Estas moléculas se adsorben sobre la superficie de las NPs y evitan que estas interaccionen directamente con las partículas vecinas. Si bien existen diversas moléculas que pueden ser utilizadas para este fin, uno de los únicos tipos de NPs metálicas cuya distribución de tamaños es estrecha, son estables a lo largo del tiempo y pueden ser obtenidas en forma de polvo, lavadas, y utilizadas como si se tratase de un compuesto químico tradicional, son las NPs cubiertas por tioles. La gran estabilidad de estas partículas está dada por la alta energía del enlace que se forma entre el azufre del grupo tiol y el metal. Resulta, entonces, particularmente interesante estudiar la interfase entre la superficie metálica y las moléculas adsorbidas. En este trabajo se presenta un estudio de la interfase Au-tiol y Pd-tiol en diferentes sistemas que van desde monocapas autoensambladas (SAMs) de tioles sobre superficies planas hasta compuestos poliméricos de tiolatos metálicos, con especial énfasis en las NPs metálicas cubiertas por tioles. El estudio de estos sistemas fue realizado mediante la utilización de diversas técnicas. En todos los experimentos se controlaron las condiciones de medida de manera tal de minimizar los daños producidos sobre las muestras. En los casos en que esto no fue posible, se intentó elucidar qué tipo de daño se estaba produciendo para realizar el análisis de los resultados teniendo en cuenta estos efectos o bien descartar los datos que hayan sido afectados por los mismos.

Noble metal incorporated MCM-41 based nanostructured mesoporous materials have attracted the attention of material researchers in recent years. Sorption characteristics of MCM materials can be improved by surface modification techniques. Besides surface modification, metal nanoparticles can also be produced within the pores of mesoporous materials. MCM-41 can act as host for several metal nanoparticles such as palladium. The present study is focused on the synthesis of Pd-MCM-41 nanocomposite catalytic materials by using different direct synthesis procedures, as well as an impregnation method. Impregnated samples were used to synthesize Pd nanoparticles inside the pores of MCM-41. In the direct hydrothermal synthesis of Pd-MCM-41, incorporation of the Pd metal was achieved by adding PdCl2, K2PdCl4 and Pd(NH3)4(NO2)3 solutions into the synthesis mixture. Syntheses were performed in acidic and basic routes. Hydrothermal synthesis was carried out in an autoclave at 120 oC. The solid product was filtered, washed, dried, calcined at 550 oC in a stream of dry air and reduced in a stream of hydrogen at 200 oC. In the case of impregnation, PdCl2 solution was added to a suspension of MCM-41. The product was evaporated to dryness, dried under vacuum and reduced with H2 gas at 200 oC. Physical and chemical properties and surface morphology of Pd-MCM-41 nanomaterials were characterized by using XRD, XPS, EDS, BET, SEM, TEM and TPR techniques. Very high Pd/Si ratios, as high as 0.45 and 0.18 were obtained in the mesoporous materials produced by the basic and acidic direct synthesis routes, respectively. The BET surface areas of these materials were found as 999 m2/g and 694 m2/g, respectively. These results showed that the basic direct synthesis procedure was highly successful for the incorporation of Pd into the mesoporous Si structure. In addition, EDS analysis of the Pd-MCM-41 materials prepared by the impregnation technique showed that Pd/Si ratios were 0.24 and 0.12 in the two samples having surface areas of 527 m2/g and 883 m2/g, respectively. In conclusion, high surface area of the material synthesized by the basic route together with a higher Pd/Si ratio makes this material more attractive for catalytic and hydrogen storage applications.

The purpose of this study is to simulate Pt&ndash / IB (IB=Ag, Au, Cu) and PtPd bimetallic catalysts with Monte Carlo method for 201, 586, 1289, and 2406 atom containing clusters in the temperature range between 298&ndash / 1000K. The simulations were based on a coordination-dependent potential model in which binary interaction parameters were used. The binary interaction parameters were determined from the available thermodynamic data and classical thermodynamics mixing rules. The equilibrium structure of the clusters was dictated as a perfect cubo-octohedral shape. In the first part of this study, Pt&ndash / Ib bimetallics were modelled in order to test the Monte Carlo program against the previously published work. In the second part of the study, the surface composition of PtPd bimetallic catalysts as a function of temperature and cluster size were estimated in order to offer further insight to the catalytic activity for CO oxidation reaction. It was found that at low temperatures Pd segregation took place on the catalyst. The Monte Carlo predictions were in good agreement with the published experimental data on the surface compositions.

This two-year longitudinal study sought to describe and evaluate a newly developed information and communication technology (ICT) environment and the associated schoolbased ICT professional development (PD) project within a State Government primary school. The overall aim of the research study was to investigate the most effective requirements to support teachers to be skilled, knowledgeable and confident in the use of ICT in their teaching roles. The teachers were the focus of the Research Study and not the students. The ICT environment and the professional development project's effectiveness was evaluated using data collected from participating teachers and the literature regarding components of effective ICT professional development. The Research Study used qualitative and interpretive methods to illuminate and expand on what it means to provide effective ICT PD within the primary school context. The components of the ICT-enhanced environment were studied in detail to provide feedback and findings that may also be useful in other educational settings with modification. The study provided evidence that, apart from providing and developing individual ICT PD components, a collection of inter-related components was necessary at the same time for successful ICT PD to be achieved. The components of the PD project have been discussed individually and collectively in terms of their effect on the research subjects, the teachers themselves. Four global factors were identified for effective ICT PD and they were used as a framework for the study. These were teacher characteristics, authenticity, support and the ICT-enhanced environment.

A novel approach for inspecting the condition of porcelain insulators based on statistical analysis of electromagnetic radiations of live insulators is demonstrated in this thesis. Physical defects such as puncture and contamination can degrade the insulators performance and result in power outages, potentiating costs to utilities. Therefore, condition assessment of line insulators has always been one of the most important aspects of maintenance programs in power networks. Realistic replicas of punctured and contaminated insulators were created in the High Voltage Lab at University of Manitoba, following the IEC standards. These defective insulators were tested under high voltage stress while the electromagnetic radiations originated from the partial discharge activities on the insulators were captured using electromagnetic sensors. During the experimental part of this thesis, a multitude of tests were conducted and resulted in measuring and recording a total of 410,000 cycles of discharge activities. The feature extraction algorithm, developed as part of this thesis, calculates the statistical features of the phase resolved interpretation of partial discharge (PD) pulses. The results of analyzing the extracted features from the radiated signature of defective insulators indicate that the scale and shape parameters of a two sided Weibull distribution function fit to the recorded measurement entail distinct information about the source of discharges that can be used to identify the source of defects. Based on the library of features extracted from the recorded electromagnetic radiations, a support vector machine (SVM) classier, developed as part of this thesis, can successfully classify the radiation signature of punctured and contaminated insulators. Therefore, the main outcome of this research was introducing a novel porcelain insulator inspection technique that can remotely differentiate the defective punctured and contaminated insulators using their electromagnetic radiation signature in a laboratory environment. By utilizing the signature of common discharge activities present in the recorded signature of all tested insulators, a gating algorithm was developed which improved the successful classification rate from 51 % to 75%. The inspection technique proposed in this research can eliminate the safety hazards involved in the live maintenance of line insulators, lower the maintenance costs, and improve the inspection efficiency considering the conventional labour intensive live maintenance assessments. / February 2016

Release of metallic fission products from fully intact tri-structural isotropic (TRISO) fuel particles raises serious concern on the safety of high temperature gas-cooled reactors (HTGRs). In TRISO particles, SiC and/or ZrC coating is considered as the major barrier for the migration of the fission products. This thesis focuses on the migration mechanism study of Ag in SiC and Pd in ZrC.The mechanism of the migration of Ag in SiC is a long-lasting mystery. None of the currently existing models could satisfactorily explain the reported experimental facts. In this work, a new mechanism, termed as the “reaction-recrystallization” model, is proposed to explain the Ag migration behavior through SiC. Designed SiC/Ag diffusion couple experiments were carried out, and the results indicate that Ag migrates in SiC by the following three steps. First, Ag reacts with SiC to form an Ag-Si alloy (reaction). Second, carbon precipitates as a second phase and subsequently reacts with the Ag-Si alloy to form new β-SiC (recrystallization). Third, the Ag-Si alloy penetrates through the SiC layer by wetting its grain boundaries (migration). The validity of the proposed model was supported by thermodynamic calculations. (Chapter 3) The finding that SiC could be recrystallized in the presence of Ag inspires the idea of Ag-assisted crack healing in SiC. Cracks were intentionally generated by indenting the bulk SiC by a Vickers indenter. After vacuum annealing with Ag powder, the indent impressions were healed by newly-formed β-SiC grains with a recovery ratio of~ 60%. Median cracks were fully healed by both newly formed SiC and Ag-Si nodules. TEM observation reveals that the newly formed β-SiC layer is presented between the Ag-Si nodule and pristine SiC crack surface and smooths the tortuous crack surface. The above result is in potential to solve the problem of brittleness of SiC as a structural material. (Chapter 4)ZrC is considered as a candidate to replace SiC in TRISO fuel particles. The migration behavior of Pd in ZrC was investigated by designed Pd/ZrC diffusion couple experiments. It is found that ZrC reacts with Pd at temperatures higher than 600 °C to form Pd3Zr and amorphous carbon. The reaction kinetics parameters, i.e., the activation energy and the reaction order, along with the inter-diffusion coefficients of Zr and Pd, were calculated based on established models. These results provide preliminary explanation to the Pd migration in ZrC (Chapter 5).

Introdução: apesar de depressão e dor serem altamente prevalentes em pacientes com Doença de Parkinson (DP), há poucos estudos sobre a relação entre esses fatores, apesar da já bem descrita potencial modulação da dor por estados emocionais. Objetivo: avaliar a percepção termoalgésica de calor e dor em método quantitativo e correlacioná-la com sintomas psiquiátricos e da Doença de Parkinson. Método: realizamos um estudo transversal avaliando características clínicas e dados psicofísicos em 31 pacientes com DP sob efeito da medicação dopaminérgica (estado “on”). Verificamos as características da DP utilizando a escala Hoehn and Yahr, realizamos uma avaliação psiquiátrica usando as escalas Inventário de Depressão de Beck (Inventário de Depressão de Beck - IDB), Mini International Neuropsychiatric Interview (MINI) de acordo com os critérios do DSM IV, e Mini Mental State Evaluation (MMSE), avaliamos queixas de dor nos últimos 90 dias usando uma escala visual analógica para dor (EVA – Escala Visual Analógica) e medimos a percepção termoalgésica através do Teste Quantitativo Sensitivo (TQS) para percepção de calor e de dor. Resultados: 31 pacientes foram avaliados. Surpreendentemente, não houve associação entre a percepção termoalgésica e as queixas de dor ou sintomas da DP. Entretanto, houve uma correlação moderada mas significativa entre sintomas depressivos medidos pela BDI e os limiares de calor e de dor (r=0.54 para calor p<0.05 e r=0.47 p<0.05 para dor). Pacientes com sintomas depressivos significativos tiveram limiares de calor e de dor maiores comparados aos sem sintomas depressivos. Esse achado se manteve após correção estatística para severidade dos sintomas da DP. Conclusão: processamento termoalgésico em pacientes com DP é mais influenciado por depressão do que pela severidade da Doença de Parkinson ou pelo nível da dor em si. Essa informação tem implicações importantes para o diagnóstico e abordagem terapêutica para pacientes com DP e dor e/ou depressão. Por exemplo, a depressão poderia ser mais sistematicamente rastreada e tratada em pacientes com DP com processamento de dor alterado. / Introduction: Although depression and pain are highly prevalent in Parkinson’s Disease (PD) patients, there is a lack of studies in their relationship, even though it is well-known that pain is potentially modulated by emotional state. Aims: To assess warm and heat pain perception in a quantitative method and correlate it with psychiatric and parkinsonian symptoms. Methods: We carried out a transversal study assessing clinical and psychophysical data in 31 patients with PD during the effect of dopaminergic medication (on state). We assessed the clinical characteristics of Parkinson's using Hoehn and Yahr (HY), performed a psychiatric evaluation using Beck Depression Inventory (BDI), Mini International Neuropsychiatric Interview (MINI) according to the DSM IV criteria and Mini Mental State Evaluation (MMSE), evaluated pain complaints in the last 90 days using a visual analogue scale for pain (VAS) and measured pain perception by means of quantitative sensory testing (QST) for warm and heat pain perception. Results: 31 patients were evaluated. Surprisingly, there was no association between thermoalgesic perception with pain complaints or parkinsonian symptoms. However, there was a moderate but significant correlation between depressive symptoms measured by BDI and warm sensation and heat pain thresholds(r=0.54 for warm p<0.05 and r=0.47 p<0.05 for heat pain). Patients with significant depressive symptoms had higher warm and heat pain thresholds compared to those without depression. This finding was maintained after statistical correction for the PD symptoms severity. Conclusion: Thermoalgesic processing in PD patients is more influenced by depression than by PD severity or level of pain itself. This information has important implications for diagnostic and therapeutic approaches for patients with PD and pain and/or depression. For instance, depression might be more systematically screened and treated in PD patients with altered pain processing.

This longitudinal mixed methods study traces the request development of eight UK based students learning German in Germany and Austria. Although language socialisation was used as an underlying contextual framework, the main focus was on the development of politeness as operationalised in requests, and the factors which may have influenced this development such as the establishment of an L2 identity and membership in communities of practice (CofPs). Five participants were English native speakers, two had grown up bilingually, one speaking Croatian and English and the other Italian and Twi, and one was a French native speaker. The requests were primarily elicited in semi-structured role plays carried out with German native speakers, yet the participants were also asked to record authentic interactions in service encounter scenarios, expected to lead to the utterance of requests. The role play data, which amount to 144 role plays, were collected before, during and after the students’ stay abroad. In-sojourn, the participants were also asked to record authentic exchanges, three of which were used in the present study. In addition, the students were also interviewed pre-in-and post-sojourn (24 interviews) and were asked to fill in an online background questionnaire before going abroad and a language engagement questionnaire while they were abroad. The role plays were coded based on the CCSARP coding scheme to determine the degree of directness and of internal and external mitigation in learner requests. The authentic data were analysed with Conversation Analysis. The data show a shift towards more directness, i.e. less internal and more external mitigation in-sojourn, thus indicating an adaptation to target community specific language behaviour. However, the degree of adaptation varied partly in line with participants’ degree of awareness of differences in linguistic politeness and identification with German society, and partly in line with the extent of their engagement with local CofPs. The variables which mostly influenced the change between pre-and in-sojourn request realisations, were the awareness of differences in linguistic politeness and the successful establishment of an L2 identity. Interaction with the host-community, which did not have a noticeable influence on the general pre- to in-sojourn change data, and awareness of difference in linguistic politeness, did however impact the change in pre- to in-sojourn request variation. The CA analysis of the authentic exchanges and the corresponding role plays both show the same preference structure for requests, thus providing researchers in the field with important new validation for role play methodology.

All nations with significant dimensions of immigration and ethnic minorities are facing policy tensions stemming from two contradicting fundamental constitutional principles. The establishment and preservation of nationhood seems to require cultural homogeneity and associated integration of the population living on a specified territory. However, the aim of integration is challenged by the principle of recognising and safeguarding cultural identities of minorities and immigrants. One of central debates concerns language policy. This country study concerns the recent relation of language policy and immigration policy in Germany. It is based on the analysis of public discourses circling around the legislative process and the subsequent application and amendment of the foreigners’ statute of 1997 and the immigration statute of 2004 including the Green card initiative (2000) and the debate about restrictive policies after the Madrid bombing (2004). It also contains a case study of the controversies on the German-only policy on the playground of a multi-ethnic school in Wedding, a district of Berlin. Recent media coverage shows that this example, picked in 2006, has since achieved a paradigmatic quality. The thesis outlines and applies aspects of critical discourse analysis for the interpretation of selected relevant texts, mainly contained in national quality newspapers. The case study is also based on interviews and use of correspondence addressed to the school.

A infecção por citomegalovírus (CMV) tem efeito duradouro na distribuição dos subtipos de células T, mas pouco se sabe sobre o seu impacto na função celular. Foi realizada uma análise de expressão global gênica em células CD4+ purificadas em 38 recipientes de transplante de células tronco hematopoéticas (HSCT) (mediana de idade 48 anos; variação 20-65 anos) estudados em média cinco anos pós transplante (mediana 4.75 anos; variação 1-20 years). A população estudada incluiu 18 pacientes com GVHD crônico ativo (cGVHD) e 20 pacientes considerados tolerantes. Tolerância foi definida como ausência de sinais e sintomas de cGVHD, assim como ausência de tratamento imunossupressor (IST) por pelo menos 2 meses com seguimento de 1 ano sem tratamento imunossupressor. A expressão gênica foi medida por Illumina bead arrays. O seroestato do CMV foi definido pela sorologia pré transplante (por ELISA). Não havia evidência documentada de reativação do CMV no momento de coleta das amostras estudadas. Doze de 54 genes candidatos associados à função imune foram associados de maneira significativa com CMV+ em pacientes com cGVHD ativo (p<0.05) (PDCD-1; GZMH, IFNG, PRF1, CST7, IL18RAP, ITGAM, CTSW, ITGAL, GBP1, CDKN1B, CXCR4), sendo que somente três genes (CD14; CD86; IER3) foram associados a CMV+ entre os pacientes tolerantes. A expressão de PD-1 significativamente maior em pacientes CMV+ e com cGVHD ativo foi confirmada em uma população independente através de estudos de imunofenotipagem. Os pacientes CMV+/cGVHD ativos tiveram um perfil compatível com ativação de células T efetoras, não sendo detectado com a mesma intensidade em pacientes tolerantes e pacientes CMV-/cGVHD ativos. Tendo como objetivo a latência da infecção, o citomegalovírus tentará evadir-se das tentativas do sistema imune de depuração viral, criando modificações que vão desde mudanças nos subtipos de linfócitos até a remodelação de cromatina por uma série de enzimas e microRNA. O ambiente caracteristicamente inflamatório do cGVHD, a produção aumentada de citocinas, a terapia imunossupressora e a reconstituição imune defeituosa das células T podem aumentar o risco de reativação do CMV, mesmo indetectável, seguido por supra-regulação de genes relacionados à ativação de células T e função efetora. O gene PD-1 pode estar supra-regulado em ativação de células T e função efetora, mas tem papel essencial na prevenção da expansão e função das células T efetoras, sendo um candidato alvo para a prevenção e tratamento do cGVHD. Entender o impacto do CMV na regulação de PD-1 em pacientes com cGVHD seria instrumental na implementação de novas terapias; portanto mais estudos com populações maiores são necessários para entendermos o impacto da imunomodulação secundária à infecção prévia por CMV no funcionamento das células T durante cGVHD. / Cytomegalovirus infection (CMV) is known to have a life-long effect on the distribution of T cell subsets, but little is known about the impact on cell function. We performed a gene expression analysis in purified CD4+ T cells from 38 hematopoietic cell transplant (HCT) recipients (median age 48; range 20-65) studied on average 5 years after HCT (median 4.75; range 1-20 years). The study population included 18 patients with active chronic GVHD (cGVHD) and 20 tolerant (TOL) patients. Tolerance was defined by absence of signs, symptoms of cGVHD and immunosuppressive therapy (IST) for at least 2 months and 1 year follow-up without immunosupressive therapy . Gene expression was measured on Illumina bead arrays. CMV status was defined by pre-transplant recipient CMV serology (by ELISA). There was no recorded evidence of CMV reactivation at the time of study. Twelve of 54 candidate genes associated with immune function and inflammation were found to be associated CMV positive serostatus in cGVHD patients at a significance threshold of p<0.05 (PDCD-1; GZMH, IFNG, PRF1, CST7, IL18RAP, ITGAM, CTSW, ITGAL, GBP1, CDKN1B, CXCR4), but only three genes (CD14; CD86; IER3) were associated with CMV serostatus in TOL patients. The significant higher PD-1 expression on CD4+ cells of CMV+/active cGVHD patients was confirmed by immunophenotype testing in an independent population. CMV+/active cGVHD patients had a profile consistent with T effector cell activation that was not present in TOL and CMV serostatus negative/active cGVHD patients. Pursuing latency, cytomegalovirus will try to evade the immune system attempts of viral clearance creating modifications varying from changes in lymphocyte subsets to chromatin remodeling by several enzymes and microRNA. The chronic GVHD characteristic inflammatory environment, increased cytokine production, immunosuppressive therapy, and impaired T cell immune reconstitution, may increase the risk of CMV reactivation, even if not detectable, followed by up-regulation of genes related to T cell activation and effector function. The PD-1 gene can be up-regulated in T cell activation and effector functions, but it also has an essential role in preventing the expansion and function of effector cells, being a candidate target for the prevention or treatment of chronic GVHD. Understanding the CMV impact on the PD-1 regulation in active cGVHD would be key on the implementation of new therapies.Thus, more studies in larger populations are needed in order to understand CMV previous infection immunomodulation impact in T cell function during chronic GVHD.