This thesis deals with the influence of microclimatic conditions (air temperature near tree/shrub top, temperature of the stem and root zone) on the wood phenology of trees (Picea abies) and shrubs (Pinus mugo) growing on the same site in the alpine tree line (ATL) ecotone. Phenological and microclimatic research was carried out in the Giant Mountains at 1,370 m a. s. l. in the 2017 vegetation period, with the aim to compare the course of wood formation depending on the microclimate, to determine the temperature thresholds of wood growth and differences in the morphology of trees and shrubs. Based on the microclimate analysis of trees and shrubs, individual variables were determined (average, average minimum, average maximum, daily amplitude of air, stem and root zone temperatures) characterizing the growing season. The collection of micro-drills of trees and shrubs took place from April to October in an interval of 6 - 11 days, which were subsequently processed and examined in the laboratory. The following phenophases of wood development were distinguished: cambial, enlarging, wall-thickening, mature cells and cells of the previous ring. Subsequently, differences in the number of cells of individual phenophases were identified between trees and shrubs. Furthermore, the temperature thresholds for...

Neste trabalho investigamos efeitos de fotoirradiação e toxinas sob membranas celulares miméticas. Foram utilizadas, como modelo de membranas lipídicas, vesiculas unilamelares gigantes (GUVs) compostas pro lipídeos oxidados e não oxidados observadas por microscopia ótica de contraste de fase. Inicialmente estudamos a foto-resposta de membranas compostas por POPC e POPG dispersas em solução contendo azul de metileno (MB). Na sequência, estudamos o efeito de toxinas formadoras de poros, Esticolisina I (ST I) e Esticolisina II (ST II), em membranas contendo lipídeos oxidados e não oxidados. Os resultados de MB (10 µM) disperso em solução de membranas compostas por POPC e o lipídeo aniônico POPG indicaram que o aumento da densidade de carga negativa nas membranas das GUVs, que favorece a ligação da moléculas positivamente carregadas como MB nas membranas, tem como consequência um aumento de permeabilidade da membrana muito mais rápído em relação a membranas compostas apenas por POPC. Isto se deve ao fato que a localização preferencial do MB na membrana de POPC:POPG favorece a formação de oxigênio singlete próximo a dupla ligação da cadeia alquílica, dando início a reação de peroxidação lipídica de maneira mais efetiva que em membrana de POPC. Os resultados da ação das toxinas STI e STII (21 nM) em GUVs contendo lipídeos não oxidados PC e esfingomielina evidenciam que apenas STII é capaz de permear estas membranas a esta concentração. Mais ainda, nossos resultados sugerem que a existência de separação de fases fluida-gel na bicamada lipidica composta por PC:SM (razão molar 1:1) favorece a ação da toxina StII. Ao analisarmos membranas contendo lipídeos hidroperoxidados (POPC-OOH) dispersas em solução contendo STII (21 nM) observamos um aumento de permeabilidade na membrana num conjunto de GUVs, associado a formação de poros, apenas em bicamadas lipídicas formadas por misturas de lipídeos oxidados (POPC) e não oxidados (POPC-OOH). Quanto maior a concentração de lipídeos oxidados na membrana mais rapidamente ocorre o aumento de permeabilidade. / In this work we investigate the effects of photoirradiation and toxins on mimetic cell membranes. As a model of lipid membranes, giant unilamellar vesicles (GUVs) composed of oxidized and oxidized pro-lipids were observed by optical phase contrast microscopy. Initially we studied the photo-response of membranes composed of POPC and POPG dispersed in solution containing methylene blue (MB). Following, we studied the effect of pore-forming toxins, Sticolysin I (ST I) and Sticolysin II (ST II), on membranes containing oxidized and non-oxidized lipids. The results of MB (10 M) dispersed in solution of membranes composed of POPC and the anionic lipid POPG indicated that the increase in the negative charge density in the membranes of GUVs, which favors the binding of positively charged molecules as MB in the membranes, consequently increases membrane permeability in regard to membranes composed only of POPC. This is due to the fact that the preferred location of the MB in the POPC: POPG membrane favors the formation of singlet oxygen near the double bond of the alkyl chain, initiating the lipid peroxidation reaction more effectively than in the POPC membrane. The results of the action of the STI and STII toxins (21 nM) on GUVs containing non oxidised lipids PC and sphingomyelin show that only STII is able to permeate these membranes at this concentration. Moreover, our results suggest that the existence of fluid-gel phase separation in the lipid bilayer composed of PC:SM (molar ratio 1:1) favors the action of the StII toxin. When analyzing membranes containing hydroperoxidized lipids (POPC-OOH) dispersed in solution containing STII (21 nM) we observed an increase in membrane permeability in a set of GUVs, associated with pore formation, only in lipid bilayers formed by mixtures of oxidized lipids (POPC-OOH) and non-oxidized ones. The higher the concentration of oxidized lipids in the membrane, the faster the permeability increases.

A Terapia Fotodinâmica é um tratamento promissor no cura de várias doenças oftalmológicas e dermatológicas, assim como tumores. Este tratamento utiliza a combinação de luz e um composto fotossensível na presença de oxigênio. Neste trabalho objetivamos entender mecanismos de fotossensibilização em membranas. Para isso, estudamos os efeitos de irradiação em Vesículas Unilamelares Gigantes (GUVs) compostas de POPC e Cardiolipina (CL) e POPC e Colesterol (Col), contendo uma molécula fotoativa (diC12-porf) ancorada à superfície dessas membranas. GUVs compostas por POPC e POPC:Col na presença da molécula fotoativa reagem ao estímulo da luz exibindo um aumento de área seguido de flutuações. O mesmo foi observado para membranas de POPC contendo menos que 50mol% de CL. Já para composições contendo 50mol% de CL, a membrana passa a formar domínios lipídicos podendo ou não ser destruída durante a irradiação. Estes domínios podem ser suprimidos com a adição de EDTA (agente quelante de íons divalentes) na solução. Ao adicionarmos CaCl2 ao meio externo das GUVs contendo EDTA, percebemos que o efeito dos domínios e destruição da membrana reaparece. Tal fato evidencia que íons Ca++ presentes em solução devem complexar com as cargas da CL, levando à formação de domínios lipídicos. Ao quantificar o aumento de área sofrido pelas membranas percebemos que a presença de CL na membrana de POPC inibe o aumento de área para concentrações acima de 40mol% de CL. Já a presença de Col na membrana parece não contribuir significativamente para o aumento de área, embora o mesmo sofra oxidação. Além disso, evidenciou-se que na presença de CL/Col o tempo de fotoclareamento de diC12-porf é muito maior do que na ausência destes. Estes resultados evidenciam que a inclusão de CL na membrana oferece um número maior de sítios de reação para o oxigênio singlete reduzindo a foto-degradação da molécula fotoativa. Já a inclusão de Col aumenta o tempo de vida da molécula fotoativa provavelmente devido ao fato da dupla ligação do Col estar mais próxima ao centro produtor de oxigênio singlete do que a dupla ligação do POPC. / Photodynamic Therapy is a promising treatment for the cure of many diseases, like tumors. This treatment uses a combination of light and a photosensitive molecule in the presence of oxygen. In this way, our objective is to understand photosensibilization mechanisms on membranes. For this purpose, we studied the effects of irradiation in Giant Unilamelar Vesicles (GUVs) composed of POPC and Cardiolipin (CL) and POPC and Cholesterol (Chol) in the presence of a photosensitive molecule (diC12-porf). When the GUVs composed of POPC or POPC and Cholesterol (Chol) in the presence of the photosensitive molecule were irradiated, increase in surface area followed by fluctuations was observed. For GUVs composed of low concentrations of CL, the membrane photo-response was similar to that observed for pure POPC. For GUVs composed of 50 mol% CL different responses to light irradiation were observed. Some lipid domains appear for GUVs in water under irradiation and the GUV might be destroyed. When the irradiation was done in the presence of EDTA (chelant agent), the formation of the domains was prevented. Further addition of CaCl2 to this solution induced the formation of domains again leading eventually to membrane disruption. These results suggest that divalent cations have effect on the binding to CL negative polar heads, favoring lipid domain formation. We quantified the area increase obtained for the GUVs. For GUVs composed of CL we observed that until 40mol% of CL, the maximum expansion reached by the membrane area was similar to that obtained for pure POPC. For 50mol% of CL the increase of area is smaller than that found for GUVs composed only by POPC. For GUVs composed of Chol the behavior of the area is similar to that found for POPC. This means that the increase of area is mainly related to POPC peroxidation, although Chol hydroperoxide must be concomitantly formed too. Further, we observed that the diC12-porf photobleaching characteristic time for GUVs composed of CL/Chol is greater than that noted for GUVs composed of POPC. This means that when we introduce CL we are increasing the possibilities of reaction of the singlet oxygen and the photosensitive molecule is protected. The insertion of Chol in the membrane also protects the photosensitive molecule.

Este trabalho objetivou estudar a reprodução da tartaruga-da-Amazônia (Podocnemis expansa) através dos resultados obtidos em 25 anos de manejo executados pelo Projeto Quelônios da Amazônia. Para tanto foi descrito um capítulo introdutório que situa o histórico e atual situação da espécie na Amazônia brasileira destacando a importância do manejo de quelônios para a conservação e alternativas de uso sustentável. No capitulo dois, o Projeto é apresentado e analisado, tendo como objetivo a proteção e manejo da reprodução dos quelônios amazônicos, principalmente da tartaruga. Neste trabalho apresentamos os resultados obtidos do manejo nos rios Purus (AC e AM), Juruá e Uatumã (AM), Amazonas (AP, PA), Araguaia (GO, TO), Crixás- Açú (GO), das Mortes (MT), Xingú, Trombetas e Tapajós (PA), Guaporé (RO) e Branco (RR). Os resultados de 52 milhões de filhotes mostram os principais incrementos no recrutamento de fêmeas e no manejo da produção de filhotes tendo como referências os rios Tapajós (PA), Xingu (PA), Branco (RR), das Mortes (MT), Purus (AM) e Amazonas (AP). No capitulo três foi estudada alometria reprodutiva em P. expansa em três praias nos rios Branco (RR), Trombetas (PA) e Araguaia (GO), entre setembro de 2002 a fevereiro de 2003. Relações alométricas foram obtidas através de regressão linear. As fêmeas com classe de massa corpórea entre 25 e 30 kg produziram mais ovos. As classes de massa corpórea das fêmeas variando de 20 a 30 kg para o Araguaia, 25 a 40 kg para Roraima, e 25 a 35 kg para Trombetas, produziram mais filhotes. Os resultados subsidiarão planos de manejo com a espécie, possibilitando ajustes em programas de ranching e farming existentes. / This study aimed to analyze the reproduction of Giant Amazon Turtle (Podocnemis expansa) based on the results from 25 years of management carried out by the Projeto Quelônios da Amazônia (Project of Chelonian species in the Amazon). The historic process and the situation in nowadays of the species in the Brazilian Amazon, pointing out the importance of chelonian management for their conservation and sustainable use is presented in the introductory chapter. The objectives of the Project related to the protection and management of the reproduction of Chelonian species in the Amazon, specially the Giant Amazon, is presented and analyzed in the chapter two. The results obtained from the management of the turtle in the Purus River (AC, AM), Juruá and Uatumã Rivers (AM), Amazonas River (AP, PA), Araguaia River (GO, TO), Crixás-Açú River (GO), das Mortes River (MT), Xingú, Trombetas and Tapajós Rivers (PA), Guaporé River (RO) and Branco River (RR) are presented in this chapter. The results from the 52 millions of young turtles showed the main increments in the females recruitment and in the management of the production of young turtles in the Tapajós River (PA), Xingu River (PA), Branco River (RR), das Mortes River (MT), Purus River (AM) and in the Amazonas River (AP). The allometry of reproduction of P. expansa in the three beaches in the Branco River (RR), Trombetas River (PA) and Araguaia River (GO) between December 2002 and December 2003 is presented in the chapter three. Allometric relationships were obtained by linear regression. The females with body mass varying from 25 to 30 kg produced more eggs. The classes of females varying from 20 to 30 kg in the Araguaia, from 25 to 40 kg in the Roraima, and from 25 to 35 kg in the Trombetas produced more young turtles. The results could be used as a basis for the species management plan, allowing the improvement of ranching and farming programs.

A broca gigante, Telchin licus, conhecida no Brasil desde 1927, na região Nordeste do Brasil, é considerada uma das principais pragas da cana-de-açúcar. Em 2007 foi registrada pela primeira vez no Estado de São Paulo, onde se concentram 60% das lavouras de cana-de-açúcar do país. Considerando-se que até o momento não existem métodos adequados para seu manejo e controle, o objetivo desta pesquisa foi caracterizar o comportamento reprodutivo de T. licus como base para o seu controle dentro de um contexto de Manejo Integrado das Pragas da cana-deaçúcar. Estes estudos servirão de suporte para o isolamento e identificação do feromônio sexual de T. licus, o qual poderá ser utilizado para o manejo e/ou controle desta praga. A presente pesquisa foi desenvolvida no Departamento de Entomologia e Acarologia da Escola Superior de Agricultura Luiz de Queiroz (ESALQ-USP), em Piracicaba SP, e em um canavial localizado em Iracemápolis SP. A partir de uma criação de T. licus em dieta artificial, verificou-se que há sincronia na emergência de machos e fêmeas de T. licus e que as fêmeas desta espécie colocam a maior parte dos ovos nas horas mais quentes do dia, entre 12:00 e 16:00h. Para o estudo do comportamento de corte desta espécie foi necessário um telado, pois verificou-se que os insetos necessitam de espaço para movimentação, a qual, inicia-se em torno das 11h da manhã e perdura até 15h; os acasalamentos ocorrem com fêmeas novas, entre 13:00 e 15:00h e duram em média 2h; fora deste intervalo de tempo os insetos permanecem em repouso. Para a verificação da existência ou não de um feromônio sexual mediando o acasalamento da espécie foi feito um ensaio no campo, no qual foi instalada uma estrutura que simula o voo da fêmea no interior da plantação de cana-de-açúcar para verificação da atração de machos selvagens. Os tratamentos foram: (a) fêmea de T. licus viva; (b) inseto estilizado com abdome feito com massa de moldar e asas verdadeiras de fêmeas de T. licus coladas com cola quente e (c) inseto estilizado com septo de borracha, impregnado com extrato de 30 glândulas de fêmeas de T. licus, acoplado no final do abdome. O número de insetos selvagens que se aproximaram e que perseguiram os diferentes tratamentos não diferiu entre si pelo teste de Duncan a 5% de probabilidade. Contudo, houve diferença marginalmente significante (P < 0,0772) no número médio de vezes em que o mesmo macho perseguiu a fêmea viva (5,1) e o inseto estilizado (0,1). Este resultado indica que somente a atração visual não foi suficiente para estimular os machos selvagens a manterem a perseguição ao inseto estilizado. Considerandose que o número médio de vezes que os machos perseguiram o inseto estilizado com o septo de borracha (1,9) não diferiu estatisticamente do tratamento fêmea viva (5,1), sugere-se que a espécie tenha um feromônio mediando o acasalamento; entretanto, outros fatores além da comunicação química estão envolvidos neste comportamento, como a atração visual, a movimentação do inseto e a presença da luz solar. / The giant sugarcane borer, Telchin licus (Drury) known in Brazil since 1927, in the Brazilian Northeast, is considered one of the main sugarcane pests. In July 2007, this pest was recorded for the first time in the state of São Paulo, where 60% of the Brazilian sugarcane culture is concentrated. Considering that to date there are no appropriate methods for its management and control, the goal of this research was to characterize T. licus reproductive behavior as a basis to control it in a context of integrated pest management of sugarcane. These studies will support the isolation and identification of the sexual pheromone of T. licus, which may be used for the management and/or control of this pest. This research was developed at the Entomology and Acarology Department of the Escola Superior de Agricultura Luiz de Queiroz (ESALQ-USP) in Piracicaba, Brazil, and a sugarcane farm located in Iracemápolis, Brazil. Rearing T. licus on an artificial diet, we found that there is synchrony in the emergence of T.licus males and females and that the females of this species oviposit most of the eggs in the hottest hours of the day, between midday and 4:00 p.m. To study the courtship of this species a greenhouse was necessary because the insects need space to move. The activity of adults begins around 11:00 a.m. and ends at 3:00 p.m. Matings occur with young females between 1:00 p.m. and 3:00 p.m. with an average duration of 2 hours. Outside this time interval the insects remain at rest. To verify the existence of a sex pheromone mediating T. licus mating a field test was made where a structure that simulates the flight of the female was installed inside the sugarcane field to check the attraction of wild males. The treatments were: (a) a live T. licus female, (b) a stylized insect with abdomen made with mass and wings taken from T. licus females and glued with hot glue and (c) a stylized insect with rubber septum impregnated with the extract of 30 glands of T. licus females attached to the end of the abdomen. The number of wild insects approaching and chasing these treatments did not differ by the Duncan test at 5% probability, however there was a marginally significant difference (P < 0.0772) on the average number of times that the same insect chased the live female (5.1) and the stylized insect (0.1). This results indicates that visual attraction alone was not enough to stimulate free males to maintain the chase to the stylized insect. Considering that the average number of times the free males chased the stylized insect with rubber septum (1.9) did not differ statistically from the live female treatment (5.1) we suggest that the species has a pheromone mediating mating. However, factors other than chemical communication are involved in this behavior, such as visual cues, the movement of the insect and the presence of sunlight.

A realização de um diagnóstico envolve várias etapas, dentre elas o exame radiográfico. Embora a experiência do profissional seja fundamental, é necessário que o mesmo se atualize constantemente, conhecendo as novas tecnologias e de que forma a era digital vem se incorporando nas mais diferentes áreas. Neste trabalho buscou-se avaliar se a tecnologia digital pode colaborar na elaboração de hipóteses diagnósticas de lesões ósseas. Para isso, foram selecionadas 24 radiografias panorâmicas nas quais existiam imagens de lesões do tipo ameloblastoma, tumor odontogênico queratocístico, mixoma e lesão central de células gigantes, atestadas por laudos anátomo-patológicos. As radiografias foram digitalizadas e entregues a 12 examinadores, sendo 3 profissionais para cada uma de 4 diferentes especialidades (radiologia, estomatologia, patologia e cirurgia buco-maxilo-facial). Os examinadores observaram as imagens em dois momentos diferentes. Primeiramente analisaram a radiografia convencional e depois a imagem digitalizada correspondente com intervalo mínimo de 30 dias. Quando do exame das imagens digitais, foi oferecida aos examinadores a opção de uso de ferramentas disponíveis no software, que pudessem auxiliá-lo no procedimento. As suas opiniões eram anotadas em formulários, cujos dados foram posteriormente tabulados e submetidos à análise estatística, por meio de equações de estimação generalizadas (EEG) e índice kappa. Os resultados possibilitaram concluir que houve equivalência na eficácia dos dois métodos avaliados, com boa concordância entre os diagnósticos dos especialistas, e que a probabilidade de acerto não depende da especialidade do observador e nem do tipo de lesão. O método digital foi o preferido para observação entre os avaliadores, sendo que a ferramenta brilho e contraste foi considerada como a melhor auxiliar na elaboração das hipóteses diagnósticas, não havendo uma padronização de valores para tal. Os resultados sugerem ainda que as ferramentas da análise digital favoreceram mais o diagnóstico de um determinado tipo de lesão em comparação aos outros. / The achievement of a diagnosis includes several steps, among them, the radiographic exam. Although the professional experience is fundamental, it is necessary that the professional has been updated constantly, learning new technologies and how the digital era has been incorporated to different areas of knowledge. This work aimed to assess if the digital technology might play a role in the elaboration of diagnostic hypothesis of bone lesions. For that, it was selected 24 panoramic radiographs in which it was possible to observe lesion images of ameloblastoma, keratinizing cystic odontogenic tumor, odontogenic myxoma and central giant cell lesion, with histophatological diagnosis. The radiographs were digitalized and delivered to 12 examiners, being 3 professionals for each one of the 4 specialties (radiology, stomatology, pathology and oral surgery). The examiners have observed the images in two different situations. First they analyzed the conventional radiography and then the corresponding digitalized images, after at least 30 days long. Joined to the digitalized images, it was provided to the examiners software facilities in order to support them in the procedures. Their opinions were filled in booking forms, whose information were tabulated and submitted to statistical analysis through generalized estimation equations (EEG) and kappa index. The outcome has indicated that there was an equivalent fficiency between the two selected methods of assessment. There was a good match of the diagnosis made by the examiners from each speciality, and the probability of a right judgment did not rely on the observer specialty nor on the type of lesion. The examiners have preferred the digital method, and the digital tools bright and contrast were considered the best support for the elaboration of diagnostic hypothesis. Moreover, it was not obtained standard values for bright or contrast. The outcome of this work also suggests that the use of digital analysis tools tends to be more effective for a specific type of lesion than others.

Die vorliegende Arbeit befasst sich mit der Molekularstrahlepitaxie und Charakterisierung von CdSe und (Cd,Mn)Se-Quantenpunkten (QP) auf ZnSe-Puffer. Die QP werden durch einen thermisch aktivierten 2D-3D Übergang eines ursprünglich zweidimensionalen CdSe/(Cd,Mn)Se-Films erzeugt. Die Mechanismen der QP-Bildung werden in-situ mittels Reflexionsbeugung hochenergetischer Elektronen und Atom-Kraft-Mikroskopie (UHV-AFM) studiert. Ex-situ Untersuchungen an vergrabenen QP-Strukturen mittels Transmissionselektronenmikroskopie (TEM) und Photolumineszenz (PL) /Magneto-PL ergänzen die in-situ Analyse der CdSe Oberfläche. Die Kombination der Analysemethoden ermöglicht erstmalig den Nachweis, dass mit der thermischen Aktivierung eine Stranski-Krastanov-Morphologie aus CdSe QP, mit einem Kern aus reinem CdSe, auf einem geschlossenen CdSe Film erzeugt werden kann. Die statistische Auswertung im UHV-AFM ergibt eine mittlere QP-Höhe von 1,6 nm, eine QP-Dichte von 1100/µm² sowie einen Durchmesser von unterhalb 10 nm. Aus diesen Parametern lässt sich als oberes Limit des QP-Volumens ein Wert von < 0,15 ML ermitteln. TEM-Messungen ergeben, dass Interdiffusion bei der Bildung der QP sowie während dem Überwachsen von untergeordneter Bedeutung ist. Im UHV-AFM zeigt sich, dass CdSe-QP unter Labormaßstäben morphologisch stabil sind. Über einen Zeitraum von 5 Tagen, sowohl im UHV als auch an Umgebungsluft, sind bei Raumtemperatur keine Reifungserscheinungen der CdSe-QP-Morphologie beobachtbar. Das Studium der Bildungskinetik führt zu der Erkenntnis, dass der 2D-3D Übergang von einem zeitlich instabilen Ausgangszustand abhängig ist und somit kinetisch determiniert. Die experimentellen Befunde deuten darauf hin, dass unmittelbar nach dem Wachstum eine Glättung der Oberfläche auf atomarer Ebene einsetzt. In einem einfachen Modell wird die QP-Bildung als Superposition der Glättung und dem Verhältnis der Wahrscheinlichkeiten des Aufwärtssprungs zum Abwärtssprung zwischen zwei ML-Terrassen beschrieben. Erste Untersuchungen zum Wachstum von (Cd,Mn)Se QP ergeben, dass es mit der thermischen Aktivierung möglich ist bis zu einer Konzentration von ca. 10 % Mn (Cd,Mn)Se QP zu erhalten. Der Einbau des Mn bewirkt eine Reduktion der mittleren QP-Dichte und QP-Höhe. Experimente auf pseudomorphem und relaxiertem ZnSe-Puffer zeigen, dass der entscheidende Einfluss des Mn nicht in der Veränderung der Verspannung liegt, sondern in einer Veränderung der Oberflächendiffusivität. In magneto-optischen Untersuchungen der (Cd,Mn)Se-QP-Strukturen wird eindeutig der Riesen-Zeemaneffekt nachgewiesen. Es werden experimentell effektive g-Faktoren bis zu einem Wert von 220 ermittelt (B = 6T). Der Vergleich mit der Rechnung zeigt, dass das Mn in den QP eingebaut ist. In dieser Arbeit wird das Verständnis der II-VI-QP-Bildung erweitert und eine verbesserte Kontrolle des QP-Ensembles erreicht. Die erzeugten semimagnetischen Strukturen stellen einen Ausgangspunkt für weitergehende optische Experimente dar, an denen in naher Zukunft gezielt einzelne Spins manipuliert und studiert werden können. / In this work CdSe and (Cd,Mn)Se Quantum Dots (QD`s) are grown on ZnSe by molecular beam epitaxy. The QD`s are obtained within a thermicall activated 2D-3D transition of an initially two-dimensional CdSe/(Cd,Mn)Se thin film. The physics behind the 2D-3D transition is investigated in-situ by reflection of high energy electron diffraction and atomic force microscopy (UHV-AFM) measurements. Additionally ex-situ data gained on buried QD structures within Transmission Electron Microscopy (TEM) and Photoluminescence (PL) /Magneto-PL measurements are presented. The study proves for the first time that after the thermal activation a Stranski-Krastanov morphology is established. A statistical evaluation of the QD morphology by UHV-AFM supplies an average QD-height of about 1.6 nm, a QD-density of about 1100/µm² and an upper diameter of about 10 nm. The total QD volume is determined to a value of below 0.15 ML. TEM on overgrown structures reveals QD`s, with a core of pure CdSe, on a closed wetting layer. The data show that interdiffusion is of minor importance for the QD formation as well as during the overgrowth. The stability of the QD morphology is investigated with the UHV-AFM at room temperature. It is shown that the CdSe QD morphology is stable at UHV as well as ambient-air conditions over a time period of 5 days. The experiments demonstrate that CdSe QD`s do not ripen on a laboratory time scale. The investigation of the formation kinetics reveals that the 2D-3D transition is dependent from a unstable precursor state and is therefore determined by kinetics. The experiments indicate that immediately after growth the surface begins to smoothen on an atomar scale. In a simple model the QD formation is described as a superposition of the smoothening and the ratio of upwards and downwards hopping between two ML terraces. First investigations on the growth of (Cd,Mn)Se QD`s show that after the incorporation of up to 10 % Mn semimagnetic QD´s are obtained by the thermal activation. The incorporation of Mn leads to a reduction of the average QD density and QD height. Experiments on pseudomorphic and relaxed ZnSe buffer are compared. It is concluded that strain is not a crucial factor for the QD formation and that probably surface processes like diffusibility of the atomic species play an important role. Magneto-optical investigations of the (Cd,Mn)Se QD structures prove the appearance of the giant-Zeemaneffect. Effective g-values of about 220 have been measured (B = 6T). In a comparison with the calculation the incorporation of Mn into the QD`s is concluded. Within this work the comprehension of the II-VI QD formation is extended and an improved control over the QD morphology is reached. The produced semimagnetic QD structures appear as a starting point for future optical investigations concerning the control of single spins.

In der vorliegenden Arbeit wird ein neuer Ansatz vorgestellt, um Lipiddomänen, die Bindungsorte peripherer und integraler Membranproteine darstellen können, zu charakterisieren. Insbesondere wurde die Analyse der Fluoreszenzlebenszeiten von NBD-markierten Lipidanaloga benutzt, um Lipiddomänen in Giant unilamellar vesicles (GUV) und darauf aufbauend, in der Plasmamembran von Säugerzellen zu untersuchen. Das typische Zeitfenster von Fluoreszenzlebenszeiten im Bereich von Nanosekunden ermöglicht es, auch sehr kurzlebige Lipiddomänen nachzuweisen. Mit Hilfe des Fluorescence lifetime imaging (FLIM) wurden für die liquid disordered (ld) und liquid ordered (lo) Domänen in GUV jeweils spezifische Werte für das Abklingen der Fluoreszenz gemessen. Sogar die Existenz von submikroskopischen Domänen in GUV konnte nachgewiesen werden. Die Fluoreszenzlebenszeit des Lipidanalogs C6-NBD-PC zeigte in der Plasmamembran von Säugerzellen eine breite Verteilung. Dies legt in Übereinstimmung mit FLIM-Experimenten an aus der Plasmamembran von HeLa-Zellen gewonnenen Giant vesicles nahe, dass in der Plasmamembran von Zellen eine Vielzahl verschiedener submikroskopischer Lipiddomänen existiert. Darauf aufbauend wurde die Fluoreszenzmikroskopie an GUV angewendet, um die Bindung von fluoreszenzmarkiertem alpha-Synuclein an mittels FLIM charakterisierte Lipiddomänen zu untersuchen. Die Experimente zeigten, dass das Protein mit hoher Affinität an negativ geladene Phospholipide unter der Vorraussetzung bindet, dass diese sich in ld Domänen befinden. Im Gegensatz dazu erfolgt keine Bindung wenn diese Lipide in lo Domänen lokalisiert sind. Im Vergleich zum wildtypischen alpha-Synuclein zeigte die Variante A30P eine geringere Affinität zur Membran, während die E46K-Variante eine stärkere Bindung zeigte. Dies deutet darauf hin, dass bei den erblichen Formen des Morbus Parkinson eine veränderte Assoziation des alpha-Synucleins mit der Membran eine Rolle spielen kann. / In the present study a novel approach to characterize lipid domains, which may provide binding sites for peripheral or integral membrane proteins, is demonstrated. In particular, analysis of fluorescence lifetimes of NBD-labeled lipid analogues was used to study lipid domains in Giant unilamellar vesicles (GUV) and – based on the GUV results – in the plasma membrane of mammalian cells. As fluorescence decays in a few nanoseconds it is possible to to detect also very short-lived lipid domains. Fluorescence Lifetime Imaging (FLIM) revealed that the fluorescence decay of NBD-lipid analogues showed domain dependent decay times in the liquid disordered (ld) and the liquid ordered (lo) phase of GUV. Even the existence of submicroscopic domains in lipid membranes could be detected by FLIM. A broad distribution of the fluorescence lifetime was found for C6-NBD-PC inserted in the plasma membrane of mammalian cells. In agreement with FLIM studies on lipid domain forming Giant vesicles derived from the plasma membrane of HeLa-cells this may suggest that a variety of submicroscopic lipid domains exists in the plasma membrane of intact mammalian cells. Based on that, fluorescence microscopy was used on GUV to study the binding of fluorescently labeled alpha-synuclein at lipid domains previously characterized by FLIM. The experiments suggested that alpha-synuclein binds with high affinity to negatively charged phospholipids, when they are embedded in a ld as opposed to a lo environment. When compared with wildtype alpha-synuclein, the disease-causing alpha-synuclein variant A30P bound less efficiently to anionic phospholipids, while the variant E46K showed enhanced binding. This suggests that an altered association of alpha-synuclein with membranes may play a role in the inherited forms of Parkinson’s disease.

Motiviert durch strukturelle Eigenschaften molekularer Ähnlichkeitsnetzwerke werden die Evolution der größten Komponente eines Netzwerkes in zwei verschiedenen stochastischen Modellen, zufälligen Hypergraphen und zufälligen Schnittgraphen, untersucht. Zuerst wird bewiesen, dass die Anzahl der Knoten in der größten Komponente d-uniformer Hypergraphen einer Normalverteilung folgt. Der Beweis nutzt dabei ausschließlich probabilistische Argumente und keine enumerative Kombinatorik. Diesem grundlegenden Resultat folgen weitere Grenzwertsätze für die gemeinsame Verteilung von Knoten- und Kantenzahl sowie Sätze zur Zusammenhangswahrscheinlichkeit zufälliger Hypergraphen und zur asymptotischen Anzahl zusammenhängender Hypergraphen. Da das Hypergraphenmodell einige Eigenschaften der Realweltdaten nur unzureichend abbildet, wird anschließend die Evolution der größten Komponente in zufälligen Schnittgraphen, die Clustereigenschaften realer Netzwerke widerspiegeln, untersucht. Es wird gezeigt, dass zufällige Schnittgraphen sich von zufälligen (Hyper-)Graphen dadurch unterscheiden, dass (bei einer durchschnittlichen Nachbaranzahl von mehr als eins) weder die größte Komponente linear noch die zweitgrößte Komponente logarithmisch groß in Abhängigkeit von der Knotenzahl ist. Weiterhin wird ein Polynomialzeitalgorithmus zur Überdeckung der Kanten eines Graphen mit möglichst wenigen Cliquen (vollständigen Graphen) beschrieben und seine asymptotische Optimalität im Modell der zufälligen Schnittgraphen bewiesen. Anschließend wird die Entwicklung der chromatischen Zahl untersucht und gezeigt, dass zufällige Schnittgraphen mit hoher Wahrscheinlichkeit mittels verschiedener Greedystrategien optimal gefärbt werden können. Letztendlich zeigen Experimente auf realen Netzen eine Übereinstimmung mit den theoretischen Vorhersagen und legen eine gegenseitige Zertifizierung der Optimalität von Cliquen- und Färbungszahl durch Heuristiken nahe. / Motivated by structural properties of molecular similarity networks we study the behaviour of the component evolution in two different stochastic network models, that is random hypergraphs and random intersection graphs. We prove gaussian distribution for the number of vertices in the giant component of a random d-uniform hypergraph. We provide a proof using only probabilistic arguments, avoiding enumerative methods completely. This fundamental result is followed by further limit theorems concerning joint distributions of vertices and edges as well as the connectivity probability of random hypergraphs and the number of connected hypergraphs. Due to deficiencies of the hypergraph model in reflecting properties of the real--world data, we switch the model and study the evolution of the order of the largest component in the random intersection graph model which reflects some clustering properties of real--world networks. We show that for appropriate choice of the parameters random intersection graphs differ from random (hyper-)graphs in that neither the so-called giant component, appearing when the average number of neighbours of a vertex gets larger than one, has linear order nor is the second largest of logarithmic order in the number of vertices. Furthermore we describe a polynomial time algorithm for covering graphs with cliques, prove its asymptotic optimality in a random intersection graph model and study the evolution of the chromatic number in the model showing that, in a certain range of parameters, these random graphs can be coloured optimally with high probability using different greedy algorithms. Experiments on real network data confirm the positive theoretical predictions and suggest that heuristics for the clique and the chromatic number can work hand in hand proving mutual optimality.

For many decades there has been a need in many industries to measure speed and position of ferrous gears. This is commonly done by converting passing gear teeth from trigger wheels to electrical impulses to calculate speed and angular position. By using Hall effect sensors or Giant Magnetoresistance sensors (GMR), a zero speed detection of gear teeth is possible while at the same time be cheap to produce and durable for harsh environments. A specially designed trigger-wheel (cogwheel created for measurements) with gear teeth in a specific pattern, exact position can be detected by using a dual sensor, even when no earlier information is available. The new design of trigger-wheel also makes this new method more accurate and universal compared to previous solutions. This thesis demonstrates and argues for the advantages of using a dual sensor for speed and angular position detection on gear wheels. Were one sensor do quantitative measurements for pattern detection in the teeth arrangements and the other sensor do qualitative measurements for position detection.