Application of pressure in the form of taping and bracing has been shown to improve proprioception, and inducing localized muscle fatigue at various musculatures has been shown to adversely affect postural control. However, the potential for pressure application to mitigate the effects of localized muscle fatigue on postural control has not yet been determined. This study investigated specifically the effects of circumferential ankle pressure (CAP) and induced ankle fatigue on postural control. Fourteen young participants (seven males and seven females) performed fatiguing sub-maximal isotonic plantar flexion exercises on an isokinetic dynamometer, in the absence and presence of a pressure cuff (60 mm Hg) used to apply CAP. Proprioceptive acuity (PA) was determined using a passive-active joint position sense test, with categorical scores (low or high PA) used as a covariate. Postural sway during quiet standing was assessed using a force platform both pre- and post-fatigue as well as in the absence and presence of CAP. Application of CAP resulted in larger postural sway in individuals with low PA, and reduced postural sway in individuals with high PA. Fatigue effects on postural sway in individuals with low PA were more substantial as compared to individuals with high PA. CAP was found to be ineffective in mitigating the effects of fatigue on postural sway in individuals with lower PA. As a whole, the results suggest a potential for CAP as an ergonomic intervention in controlling fatigue-related fall incidents, though conclusive recommendations for use are not justified. / Master of Science

Surface- and tip-enhanced resonant Raman scattering (resonant SERS and TERS) by optical phonons in a monolayer of CdSe quantum dots (QDs) is demonstrated. The SERS enhancement was achieved by employing plasmonically active substrates consisting of gold arrays with varying nanocluster diameters prepared by electron-beam lithography. The magnitude of the SERS enhancement depends on the localized surface plasmon resonance (LSPR) energy, which is determined by the structural parameters. The LSPR positions as a function of nanocluster diameter were experimentally determined from spectroscopic micro-ellipsometry, and compared to numerical simulations showing good qualitative agreement. The monolayer of CdSe QDs was deposited by the Langmuir–Blodgett-based technique on the SERS substrates. By tuning the excitation energy close to the band gap of the CdSe QDs and to the LSPR energy, resonant SERS by longitudinal optical (LO) phonons of CdSe QDs was realized. A SERS enhancement factor of 2 × 10³ was achieved. This allowed the detection of higher order LO modes of CdSe QDs, evidencing the high crystalline quality of QDs. The dependence of LO phonon mode intensity on the size of Au nanoclusters reveals a resonant character, suggesting that the electromagnetic mechanism of the SERS enhancement is dominant. Finally, the resonant TERS spectrum from CdSe QDs was obtained using electrochemically etched gold tips providing an enhancement on the order of 10⁴. This is an important step towards the detection of the phonon spectrum from a single QD. / Dieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Surface- and tip-enhanced resonant Raman scattering (resonant SERS and TERS) by optical phonons in a monolayer of CdSe quantum dots (QDs) is demonstrated. The SERS enhancement was achieved by employing plasmonically active substrates consisting of gold arrays with varying nanocluster diameters prepared by electron-beam lithography. The magnitude of the SERS enhancement depends on the localized surface plasmon resonance (LSPR) energy, which is determined by the structural parameters. The LSPR positions as a function of nanocluster diameter were experimentally determined from spectroscopic micro-ellipsometry, and compared to numerical simulations showing good qualitative agreement. The monolayer of CdSe QDs was deposited by the Langmuir–Blodgett-based technique on the SERS substrates. By tuning the excitation energy close to the band gap of the CdSe QDs and to the LSPR energy, resonant SERS by longitudinal optical (LO) phonons of CdSe QDs was realized. A SERS enhancement factor of 2 × 10³ was achieved. This allowed the detection of higher order LO modes of CdSe QDs, evidencing the high crystalline quality of QDs. The dependence of LO phonon mode intensity on the size of Au nanoclusters reveals a resonant character, suggesting that the electromagnetic mechanism of the SERS enhancement is dominant. Finally, the resonant TERS spectrum from CdSe QDs was obtained using electrochemically etched gold tips providing an enhancement on the order of 10⁴. This is an important step towards the detection of the phonon spectrum from a single QD. / Dieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

<p>Density functional theory is a formally exact theory to describe ground state properties due to the existence of the exact functional. In practice, the usefulness of density functional theory relies on the accuracy of density functional approximations. After decades of effort of functional developments, the present-day state-of-the-art density functional approximations have achieved reasonably good accuracy for small systems. However, the error grows with system size. One of the dominant errors intrinsic in the mainstream density functional approximations is the delocalization error, which arises because of the violation of Perdew-Parr-Levy-Balduz (PPLB) linearity condition. The PPLB condition governs the formulation of the density functional theory for fractional-charge systems, for which the ground state energy for the exact functional, as a function of the fractional electron number, should yield a series of line-segments across the integer points. In this dissertation, by imposing the PPLB condition in a local, size-consistent way, we develop the local scaling correction (LSC) and its updated version, the localized orbital scaling correction (LOSC), which largely improve upon the mainstream density functional approximations across system sizes. With the LOSC, we open a door towards a systematic elimination of delocalization error. Besides the ground state functional development, we also develop a gentlest ascent dynamics approach for accessing the excited states via time-independent ground state density functionals. This is also useful for exploring Kohn-Sham energy landscapes of approximate density functionals. I will also review the PPLB formulation of density functional theory for fractionally charged systems, and show that it is equivalent to the formulation normally used for fractional system calculations under certain assumptions. Furthermore, I will examine the behavior of the fractional system energy as a function of the fractional number of electrons for different mainstream functionals, and relate it to their errors for integer systems.</p> / Dissertation

L'étude du comportement électrochimique des phases intermétalliques Al2Cu, Al2CuMg, Al7Cu2Fe, (Al,Cu)16Mn4Si3 et MgZn2, caractéristiques des alliages d'aluminium 2214-T6 et 7050-T74 et réalisée à partir d'échantillons massifs synthétisés, a montré que la formation de défauts majeurs dans la couche d'oxyde, obtenue par anodisation des alliages en milieu H2SO4 200 g/l, était directement due à la présence de ces particules au sein des alliages. L'important dégagement gazeux d'oxygène qui se produit à la surface de ces particules lors de l'étape d'anodisation explique la formation de trous et de fractures dans la couche d'oxyde. En milieu marin, ces défauts facilitent la migration des ions chlorures à la surface de l'alliage mise à nu localement et favorisent par conséquent le développement de la corrosion localisée. Les résultats obtenus en milieu NaCl 35g/l ont permis de mieux comprendre le mécanisme de corrosion des phases intermétalliques ainsi que leur rôle sur la propagation des piqûres. L'élimination des particules intermétalliques de la surface des alliages lors de l'étape de décapage (avant anodisation) permet de favoriser une croissance plus régulière de la couche d'oxyde lors de l'anodisation. Par conséquent, la résistance à la corrosion des alliages 2214 et 7050 augmente considérablement, permettant d'atteindre les objectifs fixés lors de ce projet / The electrochemical behaviour of the bulk intermetallic particles such as Al2Cu, Al2CuMg, Al7Cu2Fe, (Al,Cu)16(Mn,Fe)4Si3 and MgZn2 showed that the formation of wide defects in the oxide layer during the 2214-T6 and 7050-T74 alloys anodization was directly due to the presence of these kind of particles in the microstructure which are able to sustain both high dissolution rate and high water oxidation kinetics in acidic electrolyte. In marine environment, these defects facilitate the migration of aggressive ions like chloride on the locally bare alloys and are the onset of the pitting corrosion. The results obtained in 3.5 wt.% sodium chloride electrolyte permit to understand the corrosion mechanism of the intermetallic phases and their influence on the pits propagation. The optimization of the alloys pickling conditions in order to remove this kind of particles (prior to the anodization step) has been investigated in this work. Consequence of removing intermetallic particles, the aluminium enrichment of the surface facilitates the oxide growth and the formation of regular layer. The corrosion tests on treated aluminium alloys have clearly showed the influence of the pickling step on the resistance corrosion of 2214 and 7050 alloys, reaching the objectives fixed in this project

The exponential growth of Internet applications has created new challenges for the control and administration of large-scale networks, which consist of heterogeneous elements under dynamically changing traffic conditions. These emerging applications need guaranteed service levels, beyond those supported by best-effort networks, to deliver the intended services to the end user. Several models have been proposed for a Quality of Service (QoS) framework that can provide the means to transport these services. It is desirable to find efficient routing strategies that can meet the strict routing requirements of these applications. QoS routing is considered as one of the major components of the QoS framework in communication networks. In QoS routing, paths are selected based upon the knowledge of resource availability at network nodes and the QoS requirements of traffic. Several QoS routing schemes have been proposed that differ in the way they gather information about the network state and the way they select paths based on this information. The biggest downside of current QoS routing schemes is the frequent maintenance and distribution of global state information across the network, which imposes huge communication and processing overheads. Consequently, scalability is a major issue in designing efficient QoS routing algorithms, due to the high costs of the associated overheads. Moreover, inaccuracy and staleness of global state information is another problem that is caused by relatively long update intervals, which can significantly deteriorate routing performance. Localized QoS routing, where source nodes take routing decisions based solely on statistics collected locally, was proposed relatively recently as a viable alternative to global QoS routing. It has shown promising results in achieving good routing performance, while at the same time eliminating many scalability related problems. In localized QoS routing each source-destination pair needs to determine a set of candidate paths from which a path will be selected to route incoming flows. The goal of this thesis is to enhance the scalability of QoS routing by investigating and developing new models and algorithms based on the localized QoS routing approach. For this thesis, we have extensively studied the localized QoS routing approach and demonstrated that it can achieve a higher routing performance with lower overheads than global QoS routing schemes. Existing localized routing algorithms, Proportional Sticky Routing (PSR) and Credit-Based Routing (CBR), use the blocking probability of candidate paths as the criterion for selecting routing paths based on either flow proportions or a crediting mechanism, respectively. Routing based on the blocking probability of candidate paths may not always reflect the most accurate state of the network. This has motivated the search for alternative localized routing algorithms and to this end we have made the following contributions. First, three localized bandwidth-constrained QoS routing algorithms have been proposed, two are based on a source routing strategy and the third is based on a distributed routing strategy. All algorithms utilize the quality of links rather than the quality of paths in order to make routing decisions. Second, a dynamic precautionary mechanism was used with the proposed algorithms to prevent candidate paths from reaching critical quality levels. Third, a localized delay-constrained QoS routing algorithm was proposed to provide routing with an end-to-end delay guarantee. We compared the performance of the proposed localized QoS routing algorithms with other localized and global QoS routing algorithms under different network topologies and different traffic conditions. Simulation results show that the proposed algorithms outperform the other algorithms in terms of routing performance, resource balancing and have superior computational complexity and scalability features.

INTRODUÇÃO: A esclerodermia é uma doença auto-imune, de evolução crônica, caracterizada pela esclerose progressiva do tecido conjuntivo e alterações da microcirculação. A etiologia da doença ainda não está esclarecida. Em sua patogênese ocorre dano no endotélio vascular, com ativação inflamatória e imunológica, levando ao aumento da síntese do colágeno e outras proteínas da matriz extracelular. A esclerodermia cutânea é uma doença autolimitada e as formas superficiais evoluem com resolução em meses ou anos, deixando pouca ou nenhuma seqüela. Entretanto, em dez por cento dos casos ocorrem lesões atróficas, deformantes, que retardam ou dificultam o desenvolvimento normal. Relatos da literatura apontam a fototerapia como uma modalidade terapêutica com resposta favorável nas formas cutâneas da esclerodermia. A fototerapia, através do seu efeito imunossupressor, inibe a produção do colágeno além de induzir aumento da síntese de colagenase. Este trabalho teve como objetivo avaliar o tratamento da esclerodermia cutânea com fototerapia. Utilizou-se o exame clínico e a ultra-sonografia da pele como metodologia para demonstrar os resultados obtidos com o tratamento proposto. MÉTODOS: Durante o período de janeiro a dezembro de 2007, foram selecionados 11 pacientes com diagnóstico de esclerodermia cutânea, para o tratamento com fototerapia no Setor de Alergia e Fototerapia da Clínica de Dermatologia da Santa Casa de São Paulo. Os pacientes foram classificados de acordo com o tipo de esclerodermia cutânea e o estágio evolutivo das lesões: inflamatórias ou de estado. Os tipos de fototerapia escolhidos para esse estudo foram PUVA sistêmico, PUVA tópico e UVB banda estreita. As lesões foram avaliadas pela palpação clínica em busca de resistência ao pinçamento da pele, e submetidas ao exame de ultra-som de alta freqüência, com a finalidade de mensurar a espessura da derme, antes do tratamento e ao final da 12ª semana de fototerapia. RESULTADOS: Foi observado o início da melhora clínica das lesões com média de 10 sessões de fototerapia. A palpação clínica mostrou amolecimento em todas as lesões estudadas, tanto em lesões inflamatórias como nas lesões de estado, com redução nos escores quando comparado pré e pós-tratamento. No exame de ultra-som, a maioria das lesões avaliadas mostrou diminuição da espessura da derme e apenas cinco mantiveram sua medida. Não se observou diferença na resposta ao tratamento de acordo com o tipo de fototerapia instituída. CONCLUSÕES: O tratamento proposto foi efetivo em todas as lesões, independentemente do tipo de fototerapia realizada. A melhora foi observada em todas as lesões tratadas, e comprovada pela avaliação clínica e exame de ultra-som da pele / INTRODUCTION: Scleroderma is a chronic autoimmune disease characterized by progressive connective tissue sclerosis and microcirculatory changes. Its etiology is still unknown. Its pathogenesis shows endothelial cell damage, inflammation and immunologic activation that stimulate collagen and other extra cellular matrix protein production. Localized scleroderma is a limited disease and its superficial forms may be resolved in months or years, and leave little or no sequel. However, in ten percent of the cases atrophic and deforming lesions may be observed that delay or hinder normal development. Literature reports indicate phototherapy as a limited scleroderma therapeutic modality with favorable response. Through its immunosuppressant effect, phototherapy inhibits collagen production and induces increased collagenase synthesis. This study had the purpose of evaluating the phototherapy treatment for localized scleroderma. The clinical evaluation and the skin ultrasound were used to demonstrate the results thus obtained. METHODS: From January to December 2007, eleven patients with localized scleroderma were selected for phototherapy treatment in the Allergy and Phototherapy Division, Dermatology Clinic, Santa Casa of São Paulo Hospital. They were classified according to the type of localized scleroderma and lesion evolution: inflammatory or stadial. The lesions were treated with systemic PUVA, topic PUVA or UVB narrow band. The skin lesions were assessed by clinical palpation and high-frequency ultrasound to measure dermis thickness at baseline and at the end of 12 weeks of phototherapy. RESULTS: Some clinical improvement was observed after an average of 10 phototherapeutic sessions. All skin lesions, either inflammatory or stadial, were softer at clinical palpation with scores reduction upon pre and post treatment comparison. The ultrasound showed that most of the assessed lesions presented a decrease in dermis thickness, and only five maintained their previous measure. Treatment response was similar regardless of the phototherapeutic treatment employed. CONCLUSIONS: The treatment that was proposed was effective for all the lesions, regardless of the phototherapeutic modality employed. The improvement was observed in all skin lesions and evidenced by clinical evaluation and skin ultrasound

[pt] Neste trabalho é apresentado um estudo sobre nanopartículas metálicas, passando brevemente pela Teoria de Maxwell-Garnett do meio efetivo além de ter sido feita uma pequena pesquisa acerca dos trabalhos já existentes nessa área. É apresentada ainda uma proposta de um sensor à fibra óptica baseado no fenômeno da Ressonância Plasmonica de Superfície Localizada, que utiliza essas nanopartículas cujas propriedades ópticas são sensíveis às mudanças das características do meio onde estão imersas. Esse tipo de sensor é uma ferramenta simples e muito eficiente, além de ser de baixo custo financeiro. A descrição deste sensor mostra ainda três processos distintos de fabricação dessas nanopartículas, as configurações utilizadas para a aquisição dos dados experimentais, e a análise dos mesmos, incluindo a simulação computacional feita para o melhor entendimento dos resultados obtidos. / [en] In this work a study about metallic nanoparticles is presented. A brief revision of the Maxwell-Garnett Theory for the effective medium is made, in addition to a bibliographical research concerning the existing works on the topic. A proposal of a fiber optic sensor based in the Localized Surface Plasmon Resonance phenomena using these metallic nanoparticles, whose optic properties are sensible to changes in the medium in which they are immersed, is also made. This kind of sensor is a simple and efficient tool, in addition to also having low financial cost. Three distinct processes for fabrication of these nanoparticles are discussed. The setups used for the acquisition of the experimental data and the analysis of this data, including the computational simulation made to improve the understanding of the obtained results, are also discussed.

Le travail de thèse est consacré aux interactions spatio-, temporo- et spectro- résolue de laser avec des tissus biologiques. L'objectif de cette thèse était d'étudier l'influence des nanoparticules colloïdales embarqués dans les tissus biologiques multicouches sur leurs propriétés optiques afin de fournir plus profond et / ou plus précise de sondage. Pour ce faire, les paramètres spectroscopiques intégrales et durée de vie de fluorophore dans les environs de nanoparticules métalliques ont été analysées théoriquement et expérimentalement. L’autre partie de l'étude était de proposer de nouvelles solutions algorithmiques pour l'amélioration de la performance du processus d'estimation des valeurs des propriétés optiques de la résolution spatiale des mesures spectroscopiques. La dernière partie de la thèse est la modélisation expérimentale et théorique de la cinétique de fluorophores en présence des nanoparticules d'or colloïdales. La composante ultra-courte pico-seconde (environ 100 ps) a été résolue et a été corrélée à champ dipolaire forte des nanoparticules qui compense le dipôle de la molécule / The thesis work is devoted to spatially-, temporally- and spectrally- resolved laser and biological tissue interactions. The aim of the present thesis was to investigate the influence of colloidal nanoparticles embedded into multilayered biological tissues on their optical properties in order to provide deeper and/or more precise probing. To do so, the integral spectroscopic parameters and lifetime of fluorophore in vicinity of metal nanoparticles were analyzed theoretically and experimentally. Another part of the study was to propose new algorithmic solutions for improving the performance of the estimation process of the optical properties values from spatially resolved spectroscopic measurements. The last part of the thesis was the experimental and theoretical modelling of fluorophore’s kinetics in presence of colloidal gold nanoparticles. The ultra-short pico-second component (around 100 ps) was resolved and correlated to strong nanoparticles dipole field which is compensating the molecule’s dipole

A intrusão de raiz e partículas de solo em gotejadores instalados na subsuperfície do solo, conduz à redução da uniformidade de emissão de água e compromete as condições ideais de operação e a vida útil do sistema de irrigação. Estes fatos motivaram a realização desta pesquisa, sendo propostos protótipos de emissores, cujas características físicas e funcionais impeçam a entrada de raízes e partículas de solo por sucção dentro dos mesmos, e possibilite a vazão de projeto. Desenvolveram-se quatro modelos de emissores sendo: modelo A que utiliza êmbolo; modelo B constituído por uma membrana com módulo de Young (MY) de 1000 kPa; modelo C constituído por uma membrana com MY de 1000 kPa e protetor da membrana; e, sistema protetor (tubo) do emissor (modelo D) no qual se utilizou um gotejador comercial para controlar a vazão. Uma vez que o modelo A não apresentou desempenho satisfatório, estudos posteriores com o mesmo foram interrompidos. Em fase de campo instalaram-se os modelos B, C, D, e um gotejador comercial, modelo E. Os emissores foram avaliados em laboratório em relação ao coeficiente de variação de fabricação (CVF), coeficiente de uniformidade de emissão da água (CUE) e à curva vazão versus pressão; e, instalados em vasos com cana-de-açúcar e sem cultura, para avaliação periódica quanto à capacidade em obstar a entrada de raiz e partículas de solo, sendo analisados a vazão relativa (QR), o coeficiente de variação da vazão relativa (CVQR), CUE e distúrbio de vazão (DQ). Para o emissor modelo C desenvolveram-se Equações que descrevem o comportamento da membrana que o compõe. Os resultados obtidos com a Equação de estimativa da pressão mínima foram próximos dos dados medidos em laboratório. Os emissores B e C apresentaram altos valores de CVF e CVQR, e baixos valores de CUE. Após o terceiro período de avaliação, notou-se redução na QR do modelo E, devido a entupimento por raiz. Dos emissores construídos em laboratório, o modelo C apresentou melhor desempenho quanto à variação dos dados de vazão na linha lateral, ao longo do tempo, tendo valores agrupados entre primeiro e terceiro quartil. Após 3 meses (modelo E) e 18 meses (modelos D) de funcionamento em campo, houve presença de solo e raiz, enquanto os modelos B e C apresentaram os melhores resultados quanto ao impedimento da entrada de raiz e solo dentro do emissor, sendo este último indicado para estudos mais detalhados em relação à membrana a ser utilizada. O emissor que utiliza membrana e protetor foi adequado para evitar entrada de raiz e solo dentro do mesmo, sendo necessário estudos a respeito da membrana e de um sistema para controlar a vazão. Com as Equações propostas para o modelo C serão possíveis futuros estudos que busquem aperfeiçoar o protótipo, podendo ser utilizadas para estimativa da pressão mínima de funcionamento, variação do diâmetro da membrana, e vazão do emissor. / Roots and soil particles intrusion in drippers installed in the subsurface soil leads to reduction of the water emission uniformity, and compromise the ideal conditions of operation and the lifetime of irrigation system. These facts motivated this research, being proposed prototypes of emitters whose physical and functional characteristics prevent the entry of roots and soil particles by suction into them, and allow the design flow. Four emitters models were developed: (i) A model that uses piston; (ii) B model composed by a membrane with Youngs modulus (YM) of 1000 kPa; (iii) C model composed by a membrane with YM of 1000 kPa plus a membrane protector;(iv) protector (tube) emitter system (D model) in which was used a commercial dripper to flow control. The A model study was stopped since it did not present a good performance. In the field stage models B, C, D and a commercial dripper E were installed. In the laboratory stage, emitters were evaluated in relation to the manufacturing coefficient of variation (CVF), the emission uniformity coefficient of water (EUC) and the flow rate versus pressure curve. After that, the emitters were installed in pots with and without sugar cane for periodic evaluation considering the potential to prevent the entry of roots and soil particles into the emitter. Relative flow (QR), variation coefficient of relative flow (CVQR), EUC and flow disturbance (DQ) were analyzed. Equations that describe the behavior of C model emitters membrane were developed. The results obtained with the Equation to estimating the minimum pressure were close to the measured data in laboratory. B and C emitter´s model showed the higher values of CVF and CVQR, and the lower values of EUC. After third evaluation period, reduction in QR for E model was observed due to clogging by root. Among the emitters built in the laboratory, C model showed better performance in relation to variation of data flow in lateral line, with values grouped between the first and third quartile. After 3 months (E model) and 18 months (D model) of operation in the field, the presence of soil and roots was observed, while B and C models showed the best results to avoid the entry of root and soil into the emitter. C model was recommended for detailed studies in relation to the membrane which can be used. The emitter that uses membrane plus protector was suitable to prevent entry of root and soil into them needing to studies about it membrane and a system which its possible to control the flow rate. The Equations proposed for C model can be used in: studies to improve the prototype; estimation of the minimum operation pressure; changing in the membrane diameter; and, to estimate the emitter flow. Keywords: Drip irrigation; Subsurface irrigation; Root intrusion; Technological Innovation; Prototype of emitters