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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Effect of high frequency TENS on cold hyperalgesia induced by topical menthol in healthy subjects

Iribarren, Onae 27 September 2011 (has links)
The primary aim of this study was to determine the effect of high frequency Transcutaneous Electrical Nerve Stimulation (TENS) on cold sensory function following topical application of menthol. Quantitative sensory testing was used to determine cold sensation and cold pain thresholds before and after topical application of a 40% menthol solution in 9 male and 11 female subjects. In a separate session the effect of TENS (100 HZ, constant pulse, 100µs, 20 minutes) was determined on menthol-induced cold sensation. Menthol produced a distinct cold hyperalgesia which was significantly reduced during the application of high frequency TENS. The analgesic effect of TENS persisted beyond the application period for at least 20 minutes. Menthol also reduced cold detection thresholds but TENS had no effect on this aspect of cold sensation. These data support the use of TENS as a means of treating cold hyperalgesia such as that found in neuropathic pain states.
2

Effect of high frequency TENS on cold hyperalgesia induced by topical menthol in healthy subjects

Iribarren, Onae 27 September 2011 (has links)
The primary aim of this study was to determine the effect of high frequency Transcutaneous Electrical Nerve Stimulation (TENS) on cold sensory function following topical application of menthol. Quantitative sensory testing was used to determine cold sensation and cold pain thresholds before and after topical application of a 40% menthol solution in 9 male and 11 female subjects. In a separate session the effect of TENS (100 HZ, constant pulse, 100µs, 20 minutes) was determined on menthol-induced cold sensation. Menthol produced a distinct cold hyperalgesia which was significantly reduced during the application of high frequency TENS. The analgesic effect of TENS persisted beyond the application period for at least 20 minutes. Menthol also reduced cold detection thresholds but TENS had no effect on this aspect of cold sensation. These data support the use of TENS as a means of treating cold hyperalgesia such as that found in neuropathic pain states.
3

„Vergleich der sensorischen Profile und psychologischen Faktoren von Patienten mit komplexem regionalen Schmerzsyndrom Typ I (CRPS) und Patienten mit Trauma ohne CRPS“ / Comparison of the sensory profiles und psychological factors of patients with CRPS Type I andpatients with trauma without CRPS

Hägele, Johannes Christoph January 2017 (has links) (PDF)
In dieser Arbeit werden CRPS Typ I und Patienten verglichen, die eine Fraktur oder Trauma erlitten, bzw. sich einer Operation unterziehen musste. Der Vergleich untersucht sensorische und psychologische Faktoren beider Populationen. This doctoral thesis compares psychological und QST-Data of CRPS Type I Patients and Patients who suffered under Trauma, Fracture or had to undergo surgery. / We compared the sensory profiles and psychological factors of CRPS Type I patients and patients that had a fracture, surgery or other traumas without developing a CRPS. The main focus was to detect a difference in QST ("quantitative sensory testing") profiles.
4

Small fiber involvement in Fabry's disease

He, Lan January 2009 (has links) (PDF)
Aim of Investigation: The neurological manifestations of Fabry’s disease, a rare, X-linked, multisystem disorder caused by alpha-galactosidase A deficiency and globotriosylceramide (Gb3) accumulation, include both peripheral and central nervous system symptoms. Here we evaluated a prospectively recruited cohort of patients with Fabry’s disease for pain, small nerve fiber function, and skin innervation. Methods: 66 patients (31 male and 35 female) were enrolled&#65292;31 patients were on ERT. All patients underwent quantitative sensory testing (QST), electrophysiological examination, and extra- and transcranial Doppler sonography. For pain and mood assessment standardized questionnaires were used. Skin biopsies were performed at the left distal leg in 38 patients for intraepidermal nerve fiber density (IENFD) assessment. Results: Age at examination did not differ significantly between women (40.2+/-16.2 years) and men (38.9+/-13.8; n.s.). 29/31 male and 19/35 female patients complained of acroparesthesias or neuropathic pain. QST abnormalities indicative of small fiber impairment were found in 26/31 male and 28/35 female patients. Electrophysiological examination of large fibers and autonomic fibers revealed pathological findings in 11/31 male and 3/35 female patients. All patients had normal Doppler sonography results. Indicators for depression were present in 14/31 male and 10/35 female patients. 20/31 male and 18/35 female patients had a skin biopsy, the IENFD was significantly reduced in male (2.0+/-2.8 fibers/mm) compared with female patients (6.7 +/- 4.4 fibers/mm). In 10 patients free from neurological symptoms, QST and IENFD abnormalities were still detected. Follow up examination after one year in 12 patients under ERT (2.1+/-1.7 years) showed improvement in some symptoms and in QST and neurophysiology in six patients with normal renal function. 20/35 female patients older than 40 y had concomitant diseases, while none of the 18 younger female patients did. The corresponding radio in male patients was 5/19 (>=40y) and 2/13 (<40y) respectively. Conclusions: Neuropathic pain and sensory deficits of the distal extremities are common in patients with Fabry’s disease. QST and IENFD analysis are important for early diagnosis of nerve involvement in Fabry’s disease. Small fiber function may improve under ERT in patients without severe renal impairment.
5

Evolution des stratégies de reproduction des plantes à fleurs face aux changements globaux et au déclin des pollinisateurs / Evolution of plant reproductive strategies under global change and pollinator decline

Thomann, Michel 28 November 2014 (has links)
De nombreuses populations voient leurs conditions de vie modifiées par les changements globaux. Au-delà de leurs conséquences écologiques, les changements globaux peuvent également modifier les régimes de sélection des populations. Le déclin récent des pollinisateurs pourrait altérer fortement le succès reproducteur de nombreuses populations de plantes à fleurs. Cependant, ses conséquences évolutives n'ont pas été étudiées jusqu'ici. Cette thèse traite de la possibilité d'adaptation des stratégies de reproduction des plantes face aux changements globaux et plus spécifiquement face au déclin des pollinisateurs. Cette question a été abordée en deux temps. Premièrement, l'analyse de l'abondante littérature théorique et empirique sur les systèmes de reproduction des plantes et dans un moindre mesure la construction d'un modèle d'évolution des traits floraux d'attraction ont permis de clarifier des scénarios d'évolution à court terme. Deuxièmement, une approche empirique originale a été menée, consistant à comparer directement les traits de populations ancestrales et descendantes de trois espèces annuelles, à partir de la culture en jardin commun de graines anciennes et récentes en provenance de régions où des indices de déclin des pollinisateurs existent. Cette approche permet de mettre clairement en évidence l'évolution génétique. Les données existantes indiquent que le déclin des pollinisateurs peut accentuer la limitation pollinique et par conséquent augmenter la sélection sur les traits floraux. Par ailleurs, la variation génétique substantielle dans les populations suggère que l'évolution rapide des populations de plantes est possible. L'analyse de la littérature et notre étude théorique suggèrent que l'accroissement de la capacité d'autofécondation autonome ou l'accroissement de l'attraction des pollinisateurs sont deux scénarios d'évolution possibles. Deux types de réponses évolutives ressortent de nos travaux expérimentaux. D'abord, une avancée du calendrier de floraison a été retrouvée chez les trois espèces étudiées. Ce résultat souligne le rôle de l'évolution génétique, et pas seulement de la plasticité phénotypique, dans les avancées de phénologies de printemps que l'on retrouve chez de très nombreux organismes. Ensuite, contrairement aux traits de phénologie, les traits floraux ont évolué dans des directions opposées selon les espèces. Ainsi, des traits floraux a priori plus attractifs ont évolué chez une des espèces tandis que pour une autre, des traits floraux a priori moins attractifs ont évolué, mais s'accompagnent d'une meilleure capacité d'autofécondation autonome. Cette étude confirme que les traits de reproduction des plantes peuvent évoluer en quelques décennies seulement. La possibilité du sauvetage évolutif des populations, par l'évolution rapide des traits et des stratégies de reproduction des plantes, est une perspective de recherche qui découle de ces résultats. / Global change alters life conditions of numerous populations. Beyond ecological consequences, global change can also modify selection regimes in populations. While the recent pollinator decline may specifically affect the reproductive success of flowering plants, its evolutionary consequences have not been studied yet. This thesis deals with the possibility of adaptation of plant reproductive strategies under global change and more specifically under pollinator decline. This question was addressed in two steps. First, the analysis of the extensive literature on plant mating systems, and, to a lesser extent, the construction of a model for the evolution of attractive floral traits, allowed us to clarify evolutionary scenarios at short-time scales. Second, we conducted an original empirical approach, consisting in the direct comparison of ancestral and descendant populations by re-growing old and recent seeds under identical conditions. This approach allowed us to test whether genetic evolution of reproductive traits occurred in the context of pollinator decline for three annual plant species. Data from the literature indicates that pollinator decline likely increases pollen limitation and thus selection on floral traits. Moreover, the substantial genetic variation within populations suggests that rapid evolution is possible. Increased autonomous selfing or increased pollinator attraction are two possible routes of plant adaptation to pollinator decline emerging from the analysis of the literature and from our theoretical study. Our empirical work brings out two types of evolutionary trends. Firstly, earlier flowering phenology was found in all three studied species. This result shows that genetic evolution, not only phenotypic plasticity; certainly contribute to the spring phenological advancements reported for numerous species. Secondly, unlike phenological traits, floral traits evolved in opposite directions depending on the species. Showy floral traits evolved in a species while joint evolution of autonomous selfing with a reduction of floral attractiveness seemed to evolve in another species. This study shows that plant reproductive traits can evolve in a few decades. Whether or not rapid evolution of plant reproductive traits can act as an evolutionary rescue for threatened populations is a research question that arises from these results.
6

Uma formulação alternativa e enriquecida para elementos do tipo hermitiano 2-simplex / An alternative and enriched formulation for elements type hermitian 2-simplex

Dias, Nestor Juvenal Gianotti Terra 17 July 2014 (has links)
Made available in DSpace on 2016-12-12T20:25:11Z (GMT). No. of bitstreams: 1 Nestor Juvenal G Terra Dias.pdf: 2791426 bytes, checksum: ca6d2cf5b36479b660a86c2196aa3b25 (MD5) Previous issue date: 2014-07-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The main objective of this work was to obtain an alternative formulation for the so-called Hermitian 2-simplex type-(3) elements and enrich this formulation by adding functions with null value on all the nodes of the element, however with unitary partial derivatives one node. The conventional Hermitian element is an old element with degree p=3 and the degrees of freedom are the displacements and the partial derivatives in each node of the element. The element formulated in this work and their enriched versions have C0 continuity (C1 continuity is assured only at the element nodes). The formulation of the elements is based on the Principle of Minimum Potential Energy and because it is a displacement formulation, the prescribed Neumann (partial derivatives) or the Cauchy-Robin (mixed) boundary conditions are satisfied without any difficulty at the boundary nodes. Stresses and/or fluxes are obtained without any additional post-processing of finite element solution and with precision similar to the precision obtained for displacements. In this work these elements were applied to the solution of various problems of plane elasticity, axial-symmetric elasticity, free vibration of membranes and potential problems. The main emphasis in these analyzes was to study the rates of convergence obtained with homogeneous meshes and distorted meshes. Another aspect studied was the convergence for material locking problems (EPD) and special attention was given to the analysis of error in stress (or fluxes). After several comparisons made throughout this work it was concluded that the results obtained with this type of element is better than a large majority of triangular elements available in the literature. / Objetivo principal deste trabalho foi obter uma formulação alternativa para os chamados elementos Hermitianos 2-simplex do tipo (3) e enriquecer esta formulação adicionando funções com valor nulo em todos os nós do elemento, porém com derivadas parciais unitárias em apenas um destes nós. O elemento Hermitiano convencional é um elemento antigo na literatura, possui grau p=3 e os graus de liberdade do elemento são os deslocamentos e suas derivadas parciais em cada nó. O elemento formulado neste trabalho e sua versão enriquecida possuem continuidade C0 (a continuidade C1 só é assegurada nos nós do elemento). A formulação dos elementos é baseada no Princípio da Mínima Energia Potencial e por se tratar de uma formulação de deslocamento as condições de contorno de derivadas (Neumann) ou mistas (Cauchy-Robin) que são prescritas no contorno são satisfeitas sem nenhuma dificuldade. As tensões e/ou fluxos são obtidos sem nenhum pós-processamento adicional e com precisão semelhante à dos deslocamentos. Neste trabalho estes elementos foram aplicados para a solução de diversos problemas da elasticidade plana e axi-simétrica, problemas de vibração livre de membranas e problemas de potencial. A ênfase principal nestas análises foi o estudo das taxas de convergência com malhas homogêneas e com malhas distorcidas. Outro aspecto estudado foi a convergência para os problemas de locking de Poisson e especial atenção foi dada para as análises de erro em tensões (ou fluxos) pontuais que é o ponto forte deste tipo de elemento. Após diversas comparações realizadas ao longo deste trabalho concluiu-se que os resultados obtidos com este tipo de elemento são melhores do que a grande maioria de elementos triangulares disponíveis na literatura.
7

Percepção termoalgésica em pacientes com Doença de parkinson e sintomas depressivos

Zimmermann, Ana Beatriz January 2016 (has links)
Introdução: apesar de depressão e dor serem altamente prevalentes em pacientes com Doença de Parkinson (DP), há poucos estudos sobre a relação entre esses fatores, apesar da já bem descrita potencial modulação da dor por estados emocionais. Objetivo: avaliar a percepção termoalgésica de calor e dor em método quantitativo e correlacioná-la com sintomas psiquiátricos e da Doença de Parkinson. Método: realizamos um estudo transversal avaliando características clínicas e dados psicofísicos em 31 pacientes com DP sob efeito da medicação dopaminérgica (estado “on”). Verificamos as características da DP utilizando a escala Hoehn and Yahr, realizamos uma avaliação psiquiátrica usando as escalas Inventário de Depressão de Beck (Inventário de Depressão de Beck - IDB), Mini International Neuropsychiatric Interview (MINI) de acordo com os critérios do DSM IV, e Mini Mental State Evaluation (MMSE), avaliamos queixas de dor nos últimos 90 dias usando uma escala visual analógica para dor (EVA – Escala Visual Analógica) e medimos a percepção termoalgésica através do Teste Quantitativo Sensitivo (TQS) para percepção de calor e de dor. Resultados: 31 pacientes foram avaliados. Surpreendentemente, não houve associação entre a percepção termoalgésica e as queixas de dor ou sintomas da DP. Entretanto, houve uma correlação moderada mas significativa entre sintomas depressivos medidos pela BDI e os limiares de calor e de dor (r=0.54 para calor p<0.05 e r=0.47 p<0.05 para dor). Pacientes com sintomas depressivos significativos tiveram limiares de calor e de dor maiores comparados aos sem sintomas depressivos. Esse achado se manteve após correção estatística para severidade dos sintomas da DP. Conclusão: processamento termoalgésico em pacientes com DP é mais influenciado por depressão do que pela severidade da Doença de Parkinson ou pelo nível da dor em si. Essa informação tem implicações importantes para o diagnóstico e abordagem terapêutica para pacientes com DP e dor e/ou depressão. Por exemplo, a depressão poderia ser mais sistematicamente rastreada e tratada em pacientes com DP com processamento de dor alterado. / Introduction: Although depression and pain are highly prevalent in Parkinson’s Disease (PD) patients, there is a lack of studies in their relationship, even though it is well-known that pain is potentially modulated by emotional state. Aims: To assess warm and heat pain perception in a quantitative method and correlate it with psychiatric and parkinsonian symptoms. Methods: We carried out a transversal study assessing clinical and psychophysical data in 31 patients with PD during the effect of dopaminergic medication (on state). We assessed the clinical characteristics of Parkinson's using Hoehn and Yahr (HY), performed a psychiatric evaluation using Beck Depression Inventory (BDI), Mini International Neuropsychiatric Interview (MINI) according to the DSM IV criteria and Mini Mental State Evaluation (MMSE), evaluated pain complaints in the last 90 days using a visual analogue scale for pain (VAS) and measured pain perception by means of quantitative sensory testing (QST) for warm and heat pain perception. Results: 31 patients were evaluated. Surprisingly, there was no association between thermoalgesic perception with pain complaints or parkinsonian symptoms. However, there was a moderate but significant correlation between depressive symptoms measured by BDI and warm sensation and heat pain thresholds(r=0.54 for warm p<0.05 and r=0.47 p<0.05 for heat pain). Patients with significant depressive symptoms had higher warm and heat pain thresholds compared to those without depression. This finding was maintained after statistical correction for the PD symptoms severity. Conclusion: Thermoalgesic processing in PD patients is more influenced by depression than by PD severity or level of pain itself. This information has important implications for diagnostic and therapeutic approaches for patients with PD and pain and/or depression. For instance, depression might be more systematically screened and treated in PD patients with altered pain processing.
8

Phenotypic plasticity and local adaptation in island populations of Rana temporaria

Lind, Martin January 2009 (has links)
Phenotypic plasticity is the ability of a genotype to express different phenotypes in different environments. Despite its common occurrence, few have investigated differences in plasticity between populations, the selection pressures responsible for it, and costs and constraints associated with it. In this thesis, I investigated this by studying local adaptation and phenotypic plasticity in populations of the common frog Rana temporaria, inhibiting islands with different pool types (temporary, permanent or both). The tadpoles develop in these pools, and have to finish metamorphosis before the pool dries out. I found that the tadpoles were locally adapted both in development time and in phenotypic plasticity of development time. Tadpoles from islands with temporary pools had a genetically shorter development time than tadpoles from islands with permanent pools. The population differentiation in development time, estimated as QST, was larger than the population differentiation in neutral molecular markers (FST), which suggest that divergent selection among the populations is responsible for the differentiation. Moreover, tadpoles from islands with more variation in pool drying regimes had higher phenotypic plasticity in development time than tadpoles from islands with only one pool type present. Interestingly, increased migration among populations did not select for increased plasticity, rather it was the local environmental variation that was important. This adaptation has occurred over a short time scale, as the islands are less than 300 generations old. In temporary pools, it is adaptive to finish development before the pool dries out. This could be achieved by entering the metamorphosis at a smaller size, as a smaller size takes shorter time to reach. However, I found that there is a minimum threshold size below which tadpoles’ cannot enter metamorphosis, and that there had been no evolution of this threshold size in populations living in temporary environments. That suggests that this developmental threshold is tightly linked to physiological constraints in the developmental process. Despite their expected importance as constrains on the evolution of plasticity, costs of plasticity are often not found in nature.  However, theories of why they are absent have not been tested empirically. In this thesis, I show that fitness costs of phenotypic plasticity are only found in populations with genotypes expressing high levels of phenotypic plasticity, while in populations with low-plastic genotypes, I find costs of not being plastic. This suggests that costs of plasticity increase with increased level of plasticity in the population, and that might be a reason why costs of plasticity are hard to detect.
9

An Investigation of the Suitability of Using AISI 1117 Carbon Steel in a Quench and Self-tempering Process to Satisfy ASTM A 706 Standard of Rebar

Allen, Matthew 11 August 2011 (has links)
Experiments were conducted to investigate the potential of using a quench and self-tempering heat treatment process with AISI 1117 steel to satisfy the mechanical properties of ASTM A 706 rebar. A series of quenching tests were performed and the resulting microstructure and mechanical properties studied using optical microscopy, microhardness measurement, and tensile tests. The presence of martensite throughout the samples contributed to the enhanced strength and strain-hardening ratio (tensile to yield strength) of the material. The experimental results showed that AISI 1117 is capable of meeting the ASTM standard. In addition to the experiments, a computer model using the finite difference method and incorporating heat transfer and microstructure evolution was developed to assist in future optimization of the heat treatment process.
10

An Investigation of the Suitability of Using AISI 1117 Carbon Steel in a Quench and Self-tempering Process to Satisfy ASTM A 706 Standard of Rebar

Allen, Matthew 11 August 2011 (has links)
Experiments were conducted to investigate the potential of using a quench and self-tempering heat treatment process with AISI 1117 steel to satisfy the mechanical properties of ASTM A 706 rebar. A series of quenching tests were performed and the resulting microstructure and mechanical properties studied using optical microscopy, microhardness measurement, and tensile tests. The presence of martensite throughout the samples contributed to the enhanced strength and strain-hardening ratio (tensile to yield strength) of the material. The experimental results showed that AISI 1117 is capable of meeting the ASTM standard. In addition to the experiments, a computer model using the finite difference method and incorporating heat transfer and microstructure evolution was developed to assist in future optimization of the heat treatment process.

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