Constructing a Bayesian Network requires the conditional probabilities table (CPT) to be acquired, one for each variable or node in the network. When data mining is not available, CPTs must be acquired from the domain experts. The complexity of the direct elicitation is exponential on the number of parents of a variable, making direct elicitation from human experts impractical for a large number of causes. Causal models such as Noisy-OR, Noisy-AND, Noisy-MIN, Noisy-MAX and Recursive Noisy-OR have been developed that allow CPTs acquisition to be achieved with linear complexity on the number of causes. Their representation power is measured by their ability to encode the causal interactions. Causal interactions can be categorized into two types: reinforcing and undermining. The Non-Impeding Noisy-AND or NIN-AND tree causal model, developed by Xiang and Jia, is capable of modeling both types of interaction while retaining the linear complexity. The main challenge in utilizing the NIN-AND tree model to generate a CPT is that it requires its tree topology to be elicited. A NIN-AND tree topology is an encoding of the causal interactions between the causes. In this work we present two methods, Structure Elimination (SE) and Pairwise Causal Interaction (PCI), that allow indirect elicitations of the NIN-AND tree topology using some additional probabilities elicited from experts. We conduct human-based experiment to investigate the e ectiveness of the two methods in terms of accuracy by comparing them to the Direct Numerical (DN) elicitation method. We recruit participants from second year Computer Science students at the University of Guelph. The process involves training a participant into domain expert using a known NIN-AND tree model then acquire another NIN-AND tree model by applying the SE and PCI methods. The CPTs produced by the acquired NIN-AND tree models are then compared to the one obtained by using the DN method. Comparable CPT accuracies are obtained among models generated by di erent methods, even though SE and PCI requires a much smaller number of parameters in comparison to DN.

Bilinear pairings are being used in ingenious ways to solve various protocol problems. Much research has been done on improving the efficiency of pairing computations. This thesis gives an introduction to the Tate pairing and some variants including the ate pairing, Vercauteren's pairing, and the R-ate pairing. We describe the Barreto-Naehrig (BN) family of pairing-friendly curves, and analyze three different coordinates systems (affine, projective, and jacobian) for implementing the R-ate pairing. Finally, we examine some recent work for speeding the pairing computation and provide improved estimates of the pairing costs on a particular BN curve.

The central scientific objective of this thesis was to take a broad multidisciplinary approach to make use of the full potential information to battle EDs, utilizing an interactive and translational approach running from basic science through to the clinic. In our studies we assessed a.) clinical factors and comorbidity [namely substance use in EDs (Studies 1 to 3)], b.) psychosocial, behavioural and environmental correlates of EDs (Studies 4 to 7) and c.) treatment effectiveness of specific forms of ED interventions (Studies 8 to 9). Our first line of investigation comprised Studies 1 to 3 and assessed the comorbidity of substance use in EDs. The results of these studies suggest that compared to healthy controls, substance use was higher in individuals with EDs (Studies 1 and 3), that the presence of a family history of alcohol dependence was associated with the comorbidity of EDs and substance use (Study 2) that substance use was particularly prevalent in patients with bulimic characteristics (Studies 1 to 3) and that EDs and substance abuse may represent expressions of a fundamental predisposition to addictive behaviour possibly related to the genetically influenced traits such as novelty seeking (Study 2). Furthermore, we revealed some significant differences for the specific forms of drugs in people with EDs (Studies 1 and 3), which emphasize the significance of assessing various drug types in EDs. Finally we also observed cross-cultural differences across various European countries in the prevalence of substance use in EDs and healthy controls (Study 3).The second research area was labelled psychological, behavioural and environmental correlates of EDs. In our animal study (Study 4) we found that contextual conditioning of eating response was more effective when high than low density caloric food was used. This result indicates that animal models are useful for analyzing and identifying human-animal links in feeding related behaviours. Studies 5 and 6 assessed which early individual and family eating patterns play a role in the development of EDs. Our findings agree with the growing body of research indicating that a variety of environmental and social factors are associated with dysfunctional individual and family eating patterns (e.g. food used as individualization, control and rules about food) during the first years of life and which if not detected on time could lead to a subsequent ED. Conversely, healthy eating (including eating breakfast) was negatively linked to the development of a subsequent ED. Only a few differences across ED subtypes were observed. Finally some cross-cultural differences also emerged (Study 6).In Study 7 we compared anger expressions in individuals with EDs and healthy controls and explored the relation among ED symptoms, comorbid psychopathology, personality traits and impulsive behaviours. The results indicated that individuals with EDs obtained significantly higher scores than controls on maladaptive anger expressions. When different purging methods were assessed independently, the frequency of laxative use was associated with anger suppression. ED symptoms and specific personality traits were also positively associated to different anger expressions. At last, we observed that inappropriate anger expressions were related to self-harming behaviours.Finally our last research line assessed the effectiveness of various treatments for EDs. In Study 8 we compared full and subthreshold BN in terms of personality, clinical characteristics and short-term response to a psychoeducational therapy. The results showed that full-BN and sub-BN share common psychopathological symptoms and personality traits. Furthermore, no differences in therapy outcome were observed in terms of general ED symptomatology and psychopathology. In Study 9 we described and assessed a non-symptom oriented CBT treatment in a congenitally blind women. A dramatic reduction in ED symptoms was observed after the maintaining and triggering factors had been reduced.To conclude, relatively little research has been performed towards understanding the aetiology of EDs. The findings from our investigations represent a major enhancement in the state of the art of EDs, and lead to the development of a new overall etiological model of EDs. The model we propose is a general understanding of how various ED predisposing and precipitating factors might eventually lead to EDs, and maintain the course of a disorder. Future work should address the effects of genes, environment and gene-environment interaction on the development and maintenance of EDs. Of specific interest is the query of which of these factors are non-specifically related to mental disorders and which factors may be more explicit factors that predispose an individual to EDs and related states, but not to mental disorders in general. The answers to these questions should hopefully become perceptible in the next couple of years. / El objetivo principal de esta tesis ha sido el abordar los Trastornos de la alimentación (TCA) desde una aproximación multidisciplinar, que nos ayude a combatir los TCA desde una perspectiva traslacional, en la que confluyan investigaciones básicas y aplicadas. En nuestros estudios hemos analizado en profundidad los siguientes aspectos: a.) Factores clínicos y comorbilidad [especialmente abuso de sustancias en TCA] (Estudios 1 a 3); b.) Correlatos psicosociales, conductuales y ambientales en TCA (Estudios 4 a 7); y c.) Eficacia de tratamientos específicos en TCA (Estudios 8 a 9). Nuestra primera línea de investigación (Estudios 1-3), ha estudiado la comorbilidad de abuso de sustancias en TCA. Los resultados de estos estudios sugieren que: a) abuso de sustancias es más prevalente en TCA que en sujetos de control (Estudios 1 y 3); b) la presencia abuso de sustancias en pacientes con TCA, está asociada a historia familiar previa de dependencia de alcohol (Estudio 2); c) abuso de sustancias es especialmente prevalente en pacientes con características bulímicas (Estudios 1 a 3); y d) que presencia de abuso de sustancias en TCA puede ser expresión de una predisposición a conductas adictivas, cuya susceptibilidad viene determinada por rasgos de personalidad específicos (búsqueda de sensaciones) (Estudio 2). Asimismo, encontramos aspectos diferenciales en TCA, en base al tipo de droga que consumen (Estudio 1 y 3), hecho que enfatiza la importancia de evaluar los distintos tipos de drogas utilizados por estos pacientes. Finalmente, encontramos diferencias culturales entre distintos países europeos, respecto a la prevalencia de abuso de sustancias en TCA, al ser comparados con grupos de control (estudio 3).Como segunda área de investigación, nos centramos en aspectos psicológicos, conductuales y ambientales en TCA. En un estudio, realizado siguiendo un modelo animal (estudio 4), encontramos que el condicionamiento contextual de respuesta alimentaria es más efectivo cuando es utilizado un alimento con alta densidad calórica, que cuando se utiliza un alimento con baja densidad calórica. Estos resultados sugieren qué modelos animales son útiles a la hora de analizar e identificar asociaciones entre comportamiento en humanos y animales, respecto a su conducta alimentaria.En los estudios 5 y 6 se analizaron en qué medida conductas alimentarias tempranas y patrones alimentarios en la familia, influyen en la aparición posterior de un TCA. Los resultados de estos estudios sugieren, en concordancia con un creciente volumen estudios recientes, la influencia que poseen aspectos ambientales y sociales en el desarrollo posterior de una conducta alimentaria anormal (p.e., control y reglas entorno a la alimentación). Por contrario, patrones alimentarios regulares (p.e., desayunar antes de ir al colegio) se encontró negativamente asociado (factor protector) a subsecuente desarrollo de un TCA. Asimismo, fueron encontradas limitadas diferencias entre subtipos diagnósticos, aunque algunas hacían referencia al contexto cultural (estudio 6).En el estudio 7 comparamos la expresión de ira en sujetos con un TCA y un grupo control, y analizamos su asociación con sintomatología alimentaria, psicopatología general comórbida, rasgos de personalidad y conductas impulsivas. Nuestros resultados indicaron que pacientes con TCA manifestaban sentimientos de ira de forma más inadecuada que grupos control. Al analizar los distintos procedimientos de purga, la frecuencia de abuso de laxantes iba asociada a supresión de sentimientos de ira.La sintomatología alimentaria y algunos rasgos de personalidad se asociaban a determinadas formas inadecuadas de expresión de sentimientos. Asimismo, observamos que una inadecuada expresión de sentimientos en TCA se asociaba con una mayor frecuencia de conductas autoagresivas.Finalmente, en nuestra última línea de investigación analizamos la eficacia de distintos tipos de tratamiento en TCA. En el estudio 8 comparamos casos totales y parciales de Bulimia nerviosa, en base rasgos de personalidad, sintomáticas alimentaria, psicopatología general y respuesta a un tratamiento de carácter psicoeducativo. Los resultados indicaron que los casos totales y parciales de BN comparten similitudes sintomáticas, psicopatológicas y de personalidad. Asimismo, no se obtuvieron diferencias respecto a la respuesta al tratamiento entre ambos grupos de pacientes. En el estudio 9, describimos y evaluamos un tratamiento cognitivo-conductual no centrado en los síntomas alimentarios, en una paciente ciega. En este caso, fue constatada una drástica reducción de los síntomas alimentarios tras este tipo de tratamiento.En conclusión, hasta el momento, existen escasas referencias en la literatura que sirvan para esclarecer los aspectos etiopatológicos implicados en TCA. Los resultados obtenidos en nuestras investigaciones ayudan sobre el conocimiento actual de TCA, y contribuyen al desarrollo de un nuevo modelo multimodal de entendimiento de éstos. El modelo que proponemos combina la interacción de diversos factores (predisponentes, precipitantes y mantenedores). Trabajos futuros deberían prestar atención a la relevancia que tienen factores genéticos, ambientales e interacción genes-ambiente, en el desarrollo y mantenimiento de los TCA. Un especial interés presenta la pregunta de cuáles de estos factores son específicos para trastornos mentales y cuáles los son para TCA de forma específica. / RESUM:L'objectiu principal d'aquesta tesi ha estat l'abordar els Trastorns de la conducta alimentària (TCA) des d'una aproximació multidisciplinar, que ens ajudi a combatre'ls des d'una perspectiva traslacional, en la que conflueixin investigacions bàsiques i aplicades. En els nostres estudis hem analitzat en profunditat els següents aspectes: a.) Factors clínics i comorbilitat [especialment abús de substàncies en TCA] (Estudis 1 a 3); b.) Correlats psicosocials, conductuals i ambientals en TCA (Estudis 4 a 7); i c.) Eficàcia de tractaments específics en TCA (Estudis 8 a 9).La nostra primera línia d'investigació (Estudis 1 a 3), ha estudiat la comorbilitat d'abús de substàncies en TCA. Els resultats d'aquests estudis suggereixen que: a) l'abús de substàncies és més prevalent en TCA que en subjectes control (Estudis 1 i 3); b) la presència d'abús de substàncies en pacients amb TCA, està associada a història familiar prèvia de dependència d'alcohol (Estudi 2); c) l'abús de substàncies és especialment prevalent en pacients amb característiques bulímiques (Estudis 1 a 3); i d) que la presència d'abús de substàncies en TCA pot ser expressió d'una predisposició a conductes addictives, la susceptibilitat de les quals ve determinada per trets de personalitat específics (recerca percaça de sensacions) (Estudi 2). Així mateix, trobem aspectes diferencials en TCA, en base al tipus de droga que consumeixen (Estudis 1 i 3), fet que emfatitza la importància d'avaluar els diferents tipus de drogues utilitzats per aquests pacients. Finalment trobem diferències culturals entre distints països europeus, respecte a la prevalença d'abús de substàncies en TCA, al ser comparats amb grups control (Estudi 3).Com a segona àrea d'investigació, ens centrem en aspectes psicològics, conductuals i ambientals en TCA. En un estudi realitzat seguint un model animal (Estudi 4), trobem que el condicionament contextual de resposta alimentària és més efectiu quan s'utilitza un aliment amb alta densitat calòrica, que quan se'n utilitza un amb baixa densitat calòrica. Aquests resultats suggereixen que els models animals són útils a l'hora d'analitzar i identificar associacions entre comportament en humans i animals, respecte la seva conducta alimentària.En els estudis 5 i 6 es varen analitzar fins a quin punt conductes alimentàries primerenques i patrons alimentaris en la família influeixen en l'aparició posterior d'un TCA. Els resultats d'aquests estudis suggereixen, en concordància amb un volum creixent d'estudis recents, la influència que tenen aspectes ambientals i socials en el desenvolupament posterior d'una conducta alimentària anormal (per exemple, control i normes entorn a l'alimentació). Tanmateix, patrons alimentaris regulars (per exemple, esmorzar abans d'anar a l'escola) estaven negativament associats (factor protector) al subseqüent desenvolupament d'un TCA. Així mateix, es varen trobar diferències limitades entre subtipus diagnòstics. Finalment, es varen trobar algunes diferències en relació al context sociocultural. (Estudi 6).En l'estudi 7 vàrem comparar expressió d'ira en subjectes amb un TCA i un grup control, i vàrem analitzar la seva associació amb simptomatologia alimentària, psicopatologia general comòrbida, trets de personalitat i conductes impulsives. Els nostres resultats varen indicar que pacients amb TCA manifestaven sentiments d'ira de forma més inadequada que grups control. A l'analitzar els diferents procediments de purga, la freqüència d'abús de laxants anava associada a la supressió de sentiments d'ira.La simptomatologia alimentària i determinats trets de personalitat, s'associaven a determinades formes inadequades d'expressió de sentiments. Així mateix, vàrem observar que una expressió inadequada de sentiments en TCA anava associada a una freqüència major de conductes autoagressives.Finalment, en la nostra darrera línia d'investigació vàrem analitzar l'eficàcia de diferents tipus de tractament en TCA. En l'estudi 8 vàrem comparar casos totals i parcials de Bulímia nerviosa (BN), en base a trets de personalitat, simptomatologia alimentària, psicopatologia general i resposta a un tractament de caràcter psicoeducatiu. Els resultats varen indicar que els casos totals i parcials de BN, comparteixen similituds simptomatològiques, psicopatològiques i de personalitat. Així mateix, no es varen obtenir diferències respecte a la resposta del tractament entre ambdós grups de pacients. En l'estudi 9, vàrem descriure i avaluar un tractament cognitiu-conductual no centrat en els símptomes alimentaris, en una pacient cega. En aquest cas es va constatar una reducció dràstica dels símptomes alimentaris després d'aquest tipus de tractament.Fins el moment, existeixen escasses referències en la literatura que serveixin per aclarir els aspectes etiopatogènics implicats en els TCAs. Els resultats obtinguts en les nostres investigacions ajuden en el coneixement actual dels TCA i contribueixen al desenvolupament d'un nou model multimodal per la comprensió de la seva etiologia. El model que proposem combina la interacció de diversos factors (predisponents, precipitants i mantenidors). Els treballs futurs haurien de incidir en la rellevància que tenen els factors genètics, ambientals i la interacció d'ambdós, en el desenvolupament i manteniment dels TCA. És d'especial interès la qüestió de quins d'aquests factors són específics per trastorns mentals i quins ho són per TCA.

Made available in DSpace on 2015-12-06T23:45:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2012 / Fundos para pesquisa em Cirurgia Plástica da Universidade de Pittsburgh / Introdução: Os mecanismos regulatorios desempenham papel importante na manutencao da tolerancia no transplante. pretende-se, neste estudo, desenvolver uma estrategia de tolerancia baseada na associacao de tacrolimo com rapamicina. Objetivo: Estudar efeitos de tacrolimo e rapamicina sobre as celulas T regulatorias em transplante composto de tecido alogeno. Metodos: O modelo foi de transplante composto de Ratos Brown-Norway para Lewis. Foram feitos 2 experimentos. Um para avaliar atividade reguladora dos tranplantes e outro para identificar o mecanismo de acao. No experimento 1 dividimos os ratos em 4 grupos, o experimental (tacrolimus do PO 0 ao 7 e rapamicina do PO 8 ao 21). Os outros tres: Rapamicina 21d, Tacrolimus 21d e Ambas 21d. Amostras de sangue foram colhidas para citometria de fluxo ao PO 21, PO 45. Em segundo experimento, animais divididos em 4 grupos com terapeutica semelhante ao primeiro, foram submetidos ao mesmo procedimento com coleta de sangue para a medicao dos niveis Idoleamina 2,3di-oxigenase no PO 0,5,10,15,21. Resultados: No grupo experimental nao houve rejeicao no PO 150 de 66% dos animais, em dois grupos houve 100% de rejeicao e no ultimo 75% de rejeicao. No grupo experimental houve significativo aumento nos niveis de celulas T reguladoras no PO 45 em comparacao ao PO 21. No segundo experimento, observou-se uma baixa atividade da IDO no PO 5 em animais recebendo exclusivamente tacrolimus. Conclusao: A associacao de tacrolimus e rapamicina de forma sequencial leva a um aumento de celulas T regulatoria e a tolerancia, bem como uma reduzida atividade da IDO no PO 5 em individuos recebendo exclusivamente tacrolimus / Introduction: Regulatory mechanisms play an important role on manteinance of tolerance in transplant. The intend of this study is develop a strategy for tolerance besed in the sequential association of Tacrolimus and Rapamycin. Aim: Study the efects of Tacrolimus and Rapamycin on T regulatory cells in Composite allotransplantation. Methods: The model was hind limb transplant from Brown-Norway to Lewis rats. 2 experiments were made. One to evaluate regulatory activity of transplants and another to identify its mechanism of action. On experiment 1 rats were divided in 4 groups, the experimental (Tacrolimus from POD 0 to 7 and Rapamycin from POD 8 to 21). The other 3: Rapamycin 21d, Tacrolimus 21d and both 21d. Blood samples were collected for flow cytometry on POD 21 and 45. In a second experiment animals divided in 4 groups with similar therapeutics than experiment 1, submited to the same procedure, with collect of blood samples to measure the levels of Idoleamine 2,3dioxigenase on POD 0,5,10,15,21.. Results: On experimental group there was not rejection no POD 150 of 66% of the animals, in two groups 100% rejected and in the last 75% rejected. In the experimental group was a significant increase of T regulatory cells on POD 45 comparing to POD21. ON second experiment was observed a low activity of IDO on POD 5 in animals receiving exclusevily Tacrolimus. Conclusion: The association of Tacrolimus and Rapamycin sequentialy leads to an increase of T regulatory and to tolerance and reduced activity of IDO on POD 5 of animals receiving exclusevily Tacrolimus as well. / BV UNIFESP: Teses e dissertações

The SRV test rig was used to evaluate the friction and wear properties of a lubricant in a laboratory setup. Normally, the coefficient of friction and the amount of wear that occurred are measured while the wear scar surface is also evaluated. Special attention was paid to factors that affect the repeatability. The test fluid was subjected to a friction and wear test on the SRV test rig in order to determine what factors affect the repeatability of the coefficient of friction, the amount of wear that occurred and the wear scar appearance. The test fluid used was based on rapeseed oil and white mineral oil. The fluid also contained an extreme pressure additive in the form of sulphurised ester. This was also compared for the same test fluid with dispersed hexagonal-boron nitride (h-BN) nanoparticles. The standard test method as described by ASTM D 6425, was used as test method. Instead of the standard temperature, the block temperature was increased to 100 °C in order to simulate harsher operating environments. The load was set at 200 N It was found that:  The rapid load increase from 50 to 200 N at the end of the running-in period (as described in the standard test method) caused poor repeatability. The test was modified with a more gradual load application for the duration of the running-in period (30 N/min), which resulted in improvement in the repeatability of the tests conducted.  The moisture content in the atmosphere also affected the repeatability of the friction and wear tests. This was most likely due to the formation of a corrosion layer that involves water and by keeping the relative humidity constant, a further improvement in the repeatability was observed. The addition of the h-BN nanoparticles resulted in an improvement of the repeatability of the coefficient of friction (COF), wear scar surface (WSS) and wear scar volume (WSV), since the wear scar surfaces indicated that the particles remove the corrosion layers. This could have led to more consistent wear surfaces for the duration of the test.  The particles also influenced the corrosion layer formation. For both fluids, Raman spectroscopy indicated that greigite (Fe3S4) and goethite (α-FeOOH) were found on the surface, while additional corrosion products were found on the wear scar surface for the test fluid with dispersed particles. These compounds were melanterite (FeSO4.7H2O) and rozenite (FeSO4.4H2O). All these corrosion products were most likely formed due to the reaction of iron from the specimens with sulphurised esters in the test fluid. / Dissertation (MEng)--University of Pretoria, 2015. / tm2015 / Chemical Engineering / MEng / Unrestricted

Thesis advisor: Shih-Yuan Liu / Described herein are two projects on the application and effects of BN/CC isosterism on indole-containing compounds. In the first chapter, the synthetic route to an unnatural boron and nitrogen-containing analogue of tryptophan (BN-tryptophan) via late-stage functionalization of BN-indole is disclosed and its spectroscopic properties are reported with respect to the natural amino acid, tryptophan. The incorporation of BN-tryptophan into proteins expressed in E. coli using selective pressure incorporation, a residue specific method of unnatural amino acid incorporation, is then reported and its reactivity and fluorescence in the proteins characterized. In the second chapter, the synthesis of a BN-indole-containing aromatic scaffold is reported and the cation-π binding ability characterized by nuclear magnetic resonance (NMR) monitored titrations is disclosed. The resulting chemical shifts were analyzed using a non-linear curve fitting procedure and the extracted association constants (Ka’s) compared with the natural indole scaffold. Computations were also performed to support the titration results. / Thesis (PhD) — Boston College, 2020. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

No description available.

Zweidimensionale (2D) Materialien bieten eine Vielzahl von neuartigen Eigenschaften und sind aussichtsreich Kandidaten für ein breites Spektrum an Anwendungen. Da hexagonales Bornitrid (h-BN) für eine Integration in Heterostrukturen mit anderen 2D Materialien geeignet ist, erweckte dieses in letzter Zeit großes Interesse. Insbesondere van-der-Waals-Heterostrukturen, welche h-BN und Graphen verbinden, weisen viele potenzielle Vorteile auf, verbleiben in ihrer großflächigen Herstellung von kontinuierlichen Filmen allerdings problematisch. Diese Dissertation stellt eine Untersuchung betreffend des Wachstums von h-BN und vertikalen Heterostrukturen von Graphen und h-BN auf Ni-Substraten durch Molekularstrahlepitaxie (MBE) vor. Zuerst wurde das Wachstum von h-BN mittels elementarer B- und N-Quellen auf Ni als Wachstumssubstrat untersucht. Kristalline h-BN-Schichten konnten durch Raman-spektroskopie nachgewiesen werden. Wachstumsparameter für kontinuierliche und atomar dünne Schichten wurden erlangt. Das Keimbildungs- und Wachstumsverhalten so wie die strukturelle Güte von h-BN wurden mittels einer systemischen Veränderung der Wachstumstemperatur und -dauer untersucht. Die entsprechenden Beobachtungen wie der Änderungen der bevorzugten Keimbildungszentren, der Kristallgröße und der Bedeckung des h-BN wurden diskutiert. Ein Wachstum von großflächigen vertikalen h-BN/Graphen Heterostrukturen (h-BN auf Graphen) konnte mittels einem neuartigen, MBE-basierenden Verfahren demonstriert werden, welche es h-BN und Graphen jeweils erlaubt sich in der vorteilhaften Wachstumsumgebung, welche von Ni bereitgestellt wird, zu formen. In diesem Verfahren formt sich Graphen an der Schnittstelle von h-BN und Ni durch Präzipitation von zuvor in der Ni-Schicht eingebrachten C-Atomen. Schließlich konnte noch ein großflächiges Wachstum von Graphen/h-BN-Heterostrukturen (Graphen auf h-BN) durch das direkte abscheiden von C auf MBE-gewachsenen h-BN gezeigt werden. / Two-dimensional (2D) materials offer a variety of novel properties and have shown great promise to be used in a wide range of applications. Recently, hexagonal boron nitride (h-BN) has attracted significant attention due to its suitability for integration into heterostructures with other 2D materials. In particular, van der Waals heterostructures combining h-BN and graphene offer many potential advantages, but remain difficult to produce as continuous films over large areas. This thesis presents an investigation regarding the growth of h-BN and vertical heterostructures of graphene and h-BN on Ni substrates using molecular beam epitaxy (MBE). The growth of h-BN from elemental sources of B and N was investigated initially by using Ni as the growth substrate. The presence of crystalline h-BN was confirmed using Raman spectroscopy. Growth parameters resulting in continuous and atomically thin h-BN films were obtained. By systematically varying the growth temperature and time the structural quality as well as the nucleation and growth behavior of h-BN was studied. Corresponding observations such as changes in preferred nucleation site, crystallite size, and coverage of h-BN were discussed. Growth of h-BN/graphene vertical heterostructures (h-BN on graphene) over large areas was demonstrated by employing a novel MBE-based technique, which allows both h-BN and graphene to form in the favorable growth environment provided by Ni. In this technique, graphene forms at the interface of h-BN/Ni via the precipitation of C atoms previously dissolved in the thin Ni film. No evidence for the formation of BCN alloy could be found. Additionally, the suitability of ultraviolet Raman spectroscopy for characterization of h-BN/graphene heterostructures was demonstrated. Finally, growth of large-area graphene/h-BN heterostructures (graphene on h-BN) was demonstrated via the direct deposition of C on top of MBE-grown h-BN.

Subject of this thesis is design of the steam generator for modular reactor. The dissertation consist of the theoretical part, where are described heat-exchangers and steam generators used in nuclear power plants. Second part contains theoretical calculations in the first approach (thermal, hydraulic and strenght calculation). In the next part are particular variants of steam generator selected. For the final variant are necessary calculations (introduced above) and drawings of selected parts are done. In the final statement is technical solution evaluated, and the parameters of the steam generator are compared with actually used steam generators.

A new dual-boron-cored luminogen ligated with a nitrogen-containing multidentate ligand and four bulky phenyl rings was readily synthesized. The unique molecular structure endows this BN-containing luminogen with rich photophysical properties in either solution or in the solid state, including a large Stokes shift, aggregation induced emission activity and reversible piezochromism. Furthermore, this BN-containing luminogen exhibits good capabilities for imaging living cells and sensing of fluoride anions.