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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.
181

Rupture d'interfaces en présence d'agents de surface

Roché, Matthieu 19 December 2008 (has links)
Le détachement d'une goutte est un phénomène que nous observons quotidiennement. Il résulte de la rupture de l'interface entre le fluide dispersé en goutte et le fluide environnant. Cette rupture a fait l'objet de nombreuses études. Il est bien établi que sa dynamique est régie par une compétition entre la capillarité, l'inertie, et la viscosité du fluide. Ce manuscrit décrit l'influence sur la dynamique de rupture d'une modification des propriétés de l'interface entre deux fluides à l'aide d'agents de surface. Lorsque l'agent de surface est un surfactant (SDS), la dynamique d'amincissement peut se faire selon deux modes. Deux régimes linéaires en temps constituent le premier mode. Le second mode comporte trois régimes linéaires. Dans les deux cas, l'aminicissement commence par un premier régime, suivi d'un deuxième régime de pente plus forte. Lorsque le troisième régime existe, sa pente est inférieure à celle du second régime. La variation des pentes des régimes linéaires témoigne du comportement dynamique du surfactant à l'interface. La valeur de la tension interfaciale $\gamma$ extraite du premier régime linéaire correspond à la valeur à l'équilibre de la tension interfaciale du système, $\gamma_{eq}$. La vitesse d'amincissement plus élevée au cours du second régime est reliée à une dépletion partielle en surfactant de la zone d'amincissement maximal. Le ralentissement constaté pendant le troisième régime est lié au déplacement de cette zone vers une région plus riche en surfactant, où la tension $\gamma$ est plus faible. La dynamique d'amincissement du cou est très différente lorsque des polymères de poids moléculaire intermédiaire ($\sim$ 100 kDa) sont présents simultanément avec du SDS dans la phase continue. Lorsque $C_{SDS}$ est supérieure à 0,15 fois la concentration micellaire critique (CMC), le comportement est identique à celui observé en présence de surfactant seul. En dessous de 0,15 CMC, l'amincissement ralentit exponentiellement à l'approche de la rupture, et un phénomène de beads-on-a-string apparaît. Ces constatations sont analogues à celles faites lorsqu'une solution de polymères est menée à la rupture. Dans notre cas, les polymères sont uniquement à la surface du jet et non dans son volume! Une analyse des profils du cou au cours du temps démontre l'existence d'une auto-similarité à l'approche de la rupture. Bien que les systèmes étudiés soient plus complexes, ils présentent des caractéristiques qualitativement analogues à celles observées dans des systèmes de fluides simples. Toutefois, il existe une grande différence quantitative. / Droplet detachment is ubiquitous in everyday life. It results from the rupture of an interface separating two fluids. This rupture has been widely studied. It is now well established that it relies on a competition between capillary, inertial and viscous phenomena. In this manuscript, we report on the influence on the breakup dynamics of the presence of surface agents at the interface. When SDS is used as a surface agent, thinning can proceed in two ways. In the first mode, the dynamics of thinning are characterized by two linear-in-time regimes. The second mode is made of three linear-in-time regimes. In both cases, thinning starts with a first regime, followed by a steeper second regime. When a third regime exists, its slope is softer. Slope variation bears witness to a dynamical behaviour of the surfactants at the interface. The value for the interfacial tension $\gamma$ calculated from the slope of the first linear regime is in agreement with the equilibrium interfacial tension of the system, $\gamma_{eq}$. The higher thinning speed during the second regime is linked to a partial depletion in surfactant of the maximal thinning zone. The slowdown in the tihrd regime is related to a displacement of the thinning zone in a region of higher surfactant concentration, where $\gamma$ is lower. The thinning dynamics is very different when polymers are added to the surfactant solution. If $C_{SDS}$ is higher than 0.15 times the critical micellar concentration (CMC), a behaviour similar to the pure-surfactant case is observed. Below 0.15 CMC, an exponential slowdown is observed in the last instants, as well as a "`beads-on-a-string"' phenomenon. These observations are analogous to what is seen when a solution of polymers is led to breakup. In our case, polymers are not in the bulk; they are at the interface of the two fluids! Analysis of the profiles of the neck in both cases showed that profiles are self-similar. Qualitatively, they share features with profiles observed in the case of breakup of interfaces between simple fluids. Quantitatively, slopes and angles are different.
182

Utilisation de cellules souches médullaires en bioingénierie tissulaire du ligament / Use of bone marrow mesenchymal stem cell in bioengineering of ligaments

Zhang, Lei 24 January 2008 (has links)
Les ligaments jouent un rôle important dans le mouvement et la stabilité des articulations. Les accidents et la fatigue chronique sont les principales raisons des ruptures de ligaments qui n’ont généralement pas de capacité de guérison, ce qui conduit à de graves dysfonctionnements du ligament et des articulations. La construction des ligaments en bioingénierie donne un nouvel espoir thérapeutique. Pour construire un tel tissu, les cellules sont très importantes dans la mise en oeuvre de la construction d’un biotissu ayant de bonnes propriétés tant biologiques que mécaniques. Quelle source cellulaire et quel microenvironnement doivent être utilisés pour la reconstruction des ligaments ? L’objectif de ce travail était d’étudier la différenciation des cellules souches mésenchymateuses médullaires (CSMM) en fibroblaste. Pour ce faire, d’une part, nous avons co-cultivé des CSMM du rat sans contact avec des fibroblastes ligamentaires, et d’autre part, nous avons stimulé mécaniquement les CSMM. Un suivi des ARNm et des protéines associées caractéristiques des ligaments (collagènes I et III et ténascine-C) a été analysés. Nos résultats expérimentaux ont montré que la culture des CSMM dans un microenvironnement fibroblastique de ligaments ou l’étirement favorisent les synthèses de collagènes I et III et de ténascine-C dans les proportions proches des ligaments. L’ensemble de cette étude suggère qu’il est envisageable d’utiliser les CSMM comme source cellulaire, pour une application clinique, en ingénierie tissulaire du ligaments / Ligaments play an important role in the movement and stability of joints. Accidents and chronic fatigues are the main reasons for ligament lesion which usually is difficult for self healing and leads to serious dysfunction of ligaments and joints. The construction of bioengineering ligaments gives a new way to overcome this problem. Cells are very important in the construction of a biotissue with appropriate biological as well as mechanical properties. Which cellular source and microenvironment should be used for the reconstruction of ligaments? The objective of this work is to study the differentiation of bone marrow mesenchymal stem cell (BMSC) into fibroblast. We co-cultured indirectly rat BMSC with ligament fibroblasts or stimulated them by mechanical stretching. After that, the expressions of characteristics mRNA and protein of ligaments (collagen I, III and tenascin-C) have been analyzed. Our experimental results showed that the culture of BMSC in a microenvironment of ligament fibroblast or under stretching favored the syntheses of collagen I, III and tenascin-C in the proportions close to ligaments. In summary, these studies suggest it is feasible to use BMSC as cellular source for a clinical application in tissue engineering of ligaments
183

A prática do stretching global ativo para otimização da força e prevenção de lesões em esportes de combate

Almeida Júnior, Heleno 20 February 2017 (has links)
Fundação de Apoio a Pesquisa e à Inovação Tecnológica do Estado de Sergipe - FAPITEC/SE / The objective was to analyze Global Active Stretching (GAS) practice concerning strength enhancement and injury prevention support in combat sports, it was inspected the effect of regular GAS practice on the performance of judo practioners, in physical tests and analysed the GAS effect in supporting the maintenance and restitution of normal values of upper limbs thermal asymmetry in jiu-jitsu practioners. The sample for these studies was composed by 12 judo practioners, for the period of 10 weeks and 18 jiu-jitsu practioners for the period of three consecutive days. They were separated into experimental group and control group. For judo practioners, the results show that the regular practice of GAS optimized the flexibility gain and vertical jump, with a gain of 3.00 ± (1.09) cm and 2.49 ± (0.63) cm respectively, and did not reflect on the results of the other tests. For jiu-jitsu practioners, the regular practice of GAS enhanced the healing process for the forearm area after competition, decrease in the ΔTP (°C) of 0.18°C. Therefore the regular practice of GAS increases the flexibility of back chain and the performance in vertical jump CMJ, for judo practioners, and does not interfere at the maintenance of normality of thermal , for contralateral upper limbs areas, in jiu jitsu athletes being able to restore normal values of thermal asymmetry in the forearm posterior region. / Objetivando analisar a prática do Stretching Global Ativo (SGA) para otimização da força e auxílio na prevenção de lesões em esportes de combate, verificou-se o efeito da prática regular do SGA no desempenho de judocas em uma bateria de testes físicos, assim como o efeito dessa prática no auxílio da manutenção e restituição de valores normais da assimetria térmica para membros superiores de jiujitsukas. Para compor a amostra dos estudos foram recrutados 12 judocas no período de 10 semanas e 18 jiujitsukas por três dias consecutivos, divididos em grupo experimental e grupo controle. Os resultados apontam que a prática regular do SGA potencializou o ganho de flexibilidade e impulsão vertical, com ganho de 3,00 ± 1,09 cm e 2,49 ± 0,63 respectivamente, e não foi prejudicial em outros testes para atletas de judô. Já para jiujitsukas, a prática do SGA acelerou o processo de recuperação para região do antebraço após a competição, diminuindo em 0,18°C o ΔTP (°C). Conclui-se que, a prática do SGA aumenta a flexibilidade da cadeia posterior e o desempenho no salto vertical de judocas, e não prejudica a manutenção da normalidade térmica em regiões contralaterais dos membros superiores de competidores de jiu jitsu podendo restituir valores normais de assimetria térmica na região posterior do antebraço.
184

Långsiktiga strategier för den svenska skivbranschen

Lindé, Sanna January 2006 (has links)
<p>Den här undersökningen beskriver hur den svenska skivbranschen skall överleva vid nya teknikskiften. Syftet med undersökning är att genom en fallstudie få en djup förståelse och kunskap om hur branschen och dess externa faktorer ser ut, och därefter analysera och utvärdera tre företag i skivbranschen och dess långsiktiga strategier.</p><p>Genom att ha genomfört intervjuer med tre personer från tre olika skivbolag har syftet kunnat besvaras. Intervjuerna som genomfördes var ostrukturerade och ej standardiserade, detta för att få en djup kunskap och förståelse för branschen som undersöks, samt att få ut så mycket relevant information som möjligt.</p><p>I undersökningens analys har empirin analyserats utifrån de variabler som har tagits ut från de valda teorierna. De svenska skivbolagen befinner sig på en marknad där konkurrensen är hög, vilket bolagen inte har uppmärksammat. Omstruktureringar har varit nödvändiga i organisationerna på grund av den nya digitala tekniken. Skivbolagen befinner sig i en situation där nyskapande och flexibilitet är viktiga utgångspunkter för framgång.</p><p>Skivbolagen började sent utnyttja möjligheten att sälja sin musik via distributions- och försäljningskanaler på Internet. Om bolagen utsätts för samma fenomen en gång till måste de bli mer flexibla och agera snabbare för att inte hamna i den situation som de befinner sig i idag. En annan aspekt som kommer att ha stor betydelse i framtiden är kommunikationen inom företagen så att de anställda är uppdaterade när det gäller utvecklingen inom den digitala tekniken.</p>
185

Dynamique de ponts liquides et ligaments étirés / Stretched liquid bridges and ligaments

Vincent, Lionel 13 December 2013 (has links)
Dernière étape avant l'atomisation d'un volume de liquide, les ligaments sont présents dans de nombreuses applications industrielles, de même que dans le monde qui nous entoure ; leur dynamique demeure mal comprise. L'étirement, qui permet de leur donner naissance, affecte leur évolution et la manière dont ils se fragmentent (ou non). Pour quantifier l'effet de ce dernier, nous avons choisi d'étudier des configurations modèles dans lesquelles plusieurs paramètres peuvent être bien contrôlés. Une configuration de type pont liquide permet notamment de contrôler l'étirement via le déplacement de l'un des supports solides (mors). Lorsque l'étirement imposé est modéré, il est possible de prévoir analytiquement la déviation entre la forme dynamique et la forme d'équilibre correspondante, quelle que soit la loi de déplacement du mors. Cette prédiction montre en particulier qu'un pont liquide étiré peut s'épaissir appréciablement en son centre, suggérant un retardement de la rupture. Elle montre également que l'étirement axial est réparti de manière très inhomogène. Lorsque l'étirement est suffisamment vigoureux, les résultats expérimentaux montrent que le détachement capillaire du ligament peut être significativement hâté. Le temps de rupture est relié à la masse emportée par le mors en mouvement et dépend du protocole d'étirement. Les résultats suggèrent également la possibilité d'obtenir des ligaments démesurément longs et fins sans l'intervention d'effets visqueux. / Liquid ligaments represent the last step before atomization of a liquid volume, and are encountered in a variety of industrial applications, as well as the world around us; yet, there is much to learn about their dynamics and breakup. Stretching is an essential ingredient of ligaments formation, and affect their subsequent dynamics as well as the way they break (or not). In order to quantify its action, we choose model configurations where parameters can be controlled. Liquid bridges, in particular, provide a way to impose stretching by moving one of the solid rod supporting the bridge. When stretching is not too strong, it is possible to predict analytically the shift between the dynamical shape of the bridge and the corresponding static shape, for any given rod displacement. Particularly, this prediction show that the central section of a stretched liquid bridge tend to be thicker, which could delay breakup. It also show that the axial elongation rate is far from being uniform. When stretching is vigorous, experimental results show that the ligament initial breakup can be considerably sped up. Breakup time shows to be linked to the mass taken away by the moving rod and depend on stretching protocol. Finally, results suggest that it is possible to generate infinitely long ligaments without the mediation of viscous effects.
186

Estudo de proteínas relacionadas ao costâmero em secções longitudinais de músculo sóleo de ratas imobilizadas e reabilitadas pelo alongamento passivo manual intermitente / Study of costameric proteins in soleus muscle longitudinal sections of female rats immobilized and rehabilitated by intermittent passive manual stretching

Oliveira, Letícia Cação Benedini de 04 June 2012 (has links)
No tecido muscular esquelético, a interface entre o sarcolema e a matriz extracelular é constituída por proteínas especializadas responsáveis pela transmissão de força transversal e longitudinal à miofibra. As adaptações do músculo esquelético às forças fisiológicas e patológicas, como a imobilização segmentar e exercícios de reabilitação, podem contribuir para a percepção celular dos sinais mecânicos e, consequentemente, induzir modificações na flexibilidade e na força muscular. Este estudo investigou as respostas teciduais do músculo sóleo de ratas submetido ao estresse longitudinal induzido pela associação do treinamento do tipo alongamento passivo com a livre movimentação pós-imobilização dos membros posteriores direitos. O membro posterior direito das ratas foi imobilizado por 10 dias em flexão plantar, a fim de manter o músculo sóleo em posição de encurtamento. Após a imobilização, os animais passaram por um período de alongamento passivo manual intermitente. Antes da imobilização e durante o período de alongamento e de livre movimentação, foi realizada análise funcional da marcha dos animais. Noventa e seis ratas Wistar adultas foram divididas em 8 grupos: Imobilizado (I); Imobilizado e alongado por 1 dia (IAL(1)); Imobilizado e alongado por 3 dias (IAL(3)); Imobilizado e alongado por 10 dias (IAL(10)); Imobilizado e livre por 1 dia (IL(1)); Imobilizado e livre por 3 dias (IL(3)); Imobilizado e livre por 10 dias (IL(10)); Controle do Imobilizado (C(Imob)). Após os procedimentos experimentais, o músculo sóleo foi removido e congelado, para o processamento de reação de coloração Hematoxilina-Eosina; imunoistoquímica para fibronectina, colágenos tipos I e III; imunofluorescência de laminina, distrofina e macrófagos; western blot de laminina e distrofina. Análises qualitativa e quantitativa em Microscópio de Luz e sistema de análise de imagens foram realizadas. As variáveis foram avaliadas inter- e intra-grupos pelo Modelo de Regressão Linear com Efeitos Mistos. Após a imobilização, os animais apresentaram perda de peso corporal e alterações no tamanho e formato das fibras. Ainda, a hipocinesia modificou as variáveis funcionais da marcha, reduziu a amplitude de movimento (ADM) de dorsiflexão, aumentou a relação fibras com fibronectina intracelular/número total de fibras (rFFI/NTF), a expressão de distrofina, de laminina e dos colágenos tipos I e III. Após três dias de remobilização, as alterações morfológicas estavam exacerbadas: intensa celularidade, núcleos centralizados, corpos de inclusão, necrose. Estes achados foram mais intensos no IAL(3). Os grupos IAL(3) e IL(3) também apresentaram comprometimento funcional, restrição de ADM, aumento da rFFI/NTF e da expressão do colágeno tipo III. Outros achados observados nestes grupos foram aumento da quantidade de macrófagos no tecido e de distrofina. As anormalidades relativas aos parâmetros da marcha e as alterações morfológicas geradas pela imobilização mostraram melhora no grupo IAL(10). A remobilização associada ao alongamento durante dez dias mostrou significativa efetividade na reversão das anormalidades musculoesqueléticas induzidas pelo desuso, especialmente nas variáveis funcionais. / The interface between sarcolemma and extracellular matrix in skeletal muscle tissue is constituted by specialized proteins that are responsible for the transversal and longitudinal forces transmission to the myofiber. Skeletal muscle adaptations to physiological and pathological forces, such as segmental immobilization and rehabilitation exercises, may contribute to cellular perception of mechanical signals and consequently induce alterations related to flexibility and muscular force. This study investigated the tissue responses of the soleus muscle in female rats caused by longitudinal stress induced by the association of passive stretching training with the free movement after immobilization of the right hind limb. The right hind limbs of female rats were immobilized during 10 days in a plantar flexion in order to keep the soleus muscle in a shortened position. After the immobilization, the animals were submitted to intermittent passive manual stretching. The animals gait was functionally analyzed before immobilization and during the period of stretching or free movement. Ninety-six adult female Wistar rats were divided into 8 groups: Immobilized (I); Immobilized and stretched for 1 day (IS(1)); Immobilized and stretched for 3 days (IS(3)); Immobilized and stretched for 10 days (IS(10)); Immobilized and free for 1 day (IF(1)); Immobilized and free for 3 days (IF(3)); Immobilized and free for 10 days (IF(10)); Immobilized control (C(Immob)). After the experimental period, the soleus muscle was removed, frozen and further processed by Hematoxylin-eosin stain; immunohistochemistry reactions for fibronectin, types I and III collagen; imunofluorescence of laminin, dystrophin and macrophages; western blot of dystrophin and laminin. Qualitative and quantitative results were obtained using a Light Microscope and a system of image analysis. The between- and within-group data were analyzed using Mixed-Effects Linear Models. After the immobilization, the animals presented loss of body weight and alterations in size and shape of the fibers. Furthermore, the hypokinesia changed the functional variables of gait, reduced the dorsiflexion range of motion (ROM), increased the intracellular fibronectin/total number of fibers ratio (FIF/TNFr), the expression of dystrophin, of laminin and of the types I and III collagen. After three days of remobilization, the morphological changes were exacerbated: intense cellularity, nuclear centralization, inclusion bodies and necrosis. These findings showed increased in the IS(3). The groups IS(3) and IF(3) also showed functional impairment, ROM restriction, increased FIF/TNFr and immunoreactivity of the type III collagen. Others findings observed in these groups were increase of the amount of macrophages in the tissue and of dystrophin. The abnormalities related to gait parameters and the morphological changes induced by immobilization were improved in the IS(10) group. The remobilization using stretching for ten days showed significant effectiveness and reverted the skeletal muscle abnormalities induced by disuse, especially concerning the functional variables.
187

Långsiktiga strategier för den svenska skivbranschen

Lindé, Sanna January 2006 (has links)
Den här undersökningen beskriver hur den svenska skivbranschen skall överleva vid nya teknikskiften. Syftet med undersökning är att genom en fallstudie få en djup förståelse och kunskap om hur branschen och dess externa faktorer ser ut, och därefter analysera och utvärdera tre företag i skivbranschen och dess långsiktiga strategier. Genom att ha genomfört intervjuer med tre personer från tre olika skivbolag har syftet kunnat besvaras. Intervjuerna som genomfördes var ostrukturerade och ej standardiserade, detta för att få en djup kunskap och förståelse för branschen som undersöks, samt att få ut så mycket relevant information som möjligt. I undersökningens analys har empirin analyserats utifrån de variabler som har tagits ut från de valda teorierna. De svenska skivbolagen befinner sig på en marknad där konkurrensen är hög, vilket bolagen inte har uppmärksammat. Omstruktureringar har varit nödvändiga i organisationerna på grund av den nya digitala tekniken. Skivbolagen befinner sig i en situation där nyskapande och flexibilitet är viktiga utgångspunkter för framgång. Skivbolagen började sent utnyttja möjligheten att sälja sin musik via distributions- och försäljningskanaler på Internet. Om bolagen utsätts för samma fenomen en gång till måste de bli mer flexibla och agera snabbare för att inte hamna i den situation som de befinner sig i idag. En annan aspekt som kommer att ha stor betydelse i framtiden är kommunikationen inom företagen så att de anställda är uppdaterade när det gäller utvecklingen inom den digitala tekniken.
188

Climate dynamics of the South Pacific Convergence Zone and similarities with other subtropical convergence zones in the Southern Hemisphere

Widlansky, Matthew J. 15 November 2010 (has links)
Three semi-permanent cloud bands exist in the Southern Hemisphere extending southeastward from the equator, through the tropics, and into the subtropics. The most prominent of these features occurs in the South Pacific and is referred to as the South Pacific Convergence Zone (SPCZ). Similar convergence zones, with less intensity, exist in the South Atlantic (SACZ) and Indian (SICZ) oceans. We attempt to explain the physical mechanisms that promote the diagonal orientation of the SPCZ and the processes that determine the timescales of its variability. It is argued that the slowly varying sea surface temperature patterns produce upper tropospheric wind fields that vary substantially in longitude. Regions where 200 hPa zonal winds decrease with longitude (i.e., negative zonal stretching deformation, or dU/dx<0) reduce the group speed of the eastward propagating synoptic (3-6 day period) Rossby waves and locally increase the wave energy density. Such a region of wave accumulation occurs in the vicinity of the SPCZ, thus providing a physical basis for the diagonal orientation and earlier observations that the zone acts as a "graveyard" of propagating synoptic disturbances. In essence, dU/dx=0 demarks the boundary of the graveyard while regions where dU/dx<0 denote the graveyard itself. Composites of the life cycles of synoptic waves confirm this hypothesis. From the graveyard hypothesis comes a more general theory accounting for the SPCZ's spatial orientation and its longer term variability influenced by the El Niño-Southern Oscillation (ENSO), or alternatively, the changing background SST associated with different phases of ENSO.
189

I-V transport measurements of a single unsupported MWCNT under various bending deformations

Kim, Suenne 25 January 2011 (has links)
The first part of this dissertation is an introduction describing a brief historical background of carbon nanotubes (CNTs) and their pseudo 1D structure responsible for many exotic electronic properties. The second part describes our experimental setup. The third part is about the growing of Multi-Walled Carbon Nanotubes (MWCNTs) by the chemical vapor deposition (CVD) method. Then the fourth part demonstrates a simple but reliable method to make firm contact junctions between MWCNTs and metals such as tungsten (W). The novel point of our method consists, after making a mechanical preliminary contact at a selected MWCNT, in applying a series of voltage pulses across the contact. Thin oxide layers that may form between the MWCNT and the W wire, are removed in steps by the resistive heating and electron impact during the application of each voltage pulse. Furthermore, this simple process of contact welding in steps does not bring about any permanent change in the electronic transport properties of the MWCNTs. The fifth part discusses our bending experiments. We apply a uniform and continuous bending to a selected MWCNT at room and liquid nitrogen temperatures to study the strain effect on the electrical transport in the MWCNT. There are a few published experimental works related to the bending deformation; however, this is the first study of electronic transport properties in continuous bending and releasing deformations. We observed a saturation behavior with the MWCNT and also found the bending deformation causing an anomalous change in the saturation behavior. In the sixth part we depict some interesting phenomena due to the stretching deformation of MWCNT, where we were able to propose a simple model for electron localization induced by the deformation. The last part deals with the formation of the "X-junction" between two MWCNTs. A strong X-junction can be formed simply by means of the e-beam inside the Scanning Electron Microscope (SEM). The X-junctions may form the basic elements of nano-electronic circuits such as various metal-insulator junctions, quantum dots, and similar devices. / text
190

Tratamento de dores musculares crônicas : comparação de dois métodos fisioterapêuticos

Bruscatto, Cláudia Adriana January 2006 (has links)
Dor é sintoma comum a diversos quadros clínicos. É provavelmente a razão mais freqüente de auxílio médico. Estima-se que 10 a 20% da população adulta apresentam dor crônica, sendo que, destes, cerca de 5% apresentam pouca resposta a tratamento. A abordagem terapêutica da dor crônica de origem muscular deve ser multidisciplinar, com interrupção do ciclo de dor. Para tal, são utilizadas várias técnicas, entre elas, alongamento muscular e estimulação elétrica nervosa transcutânea (TENS). O presente trabalho de pesquisa teve como objetivo avaliar a resposta analgésica de cinco sessões de fisioterapia com alongamento e/ou TENS, em dores crônicas com origem na musculatura da coluna vertebral. Foi realizado ensaio clínico randomizado, duplo-cego, em paralelo, controlado por alongamento muscular, no Centro Corpo em Porto Alegre, RS, Brasil. Foram estudados pacientes portadores de dor crônica de origem muscular, com localização na coluna vertebral. Tratava-se de pacientes adultos, com diagnóstico de dor há mais de 6 meses, feito por médico ortopedista, e que estavam iniciando tratamento fisioterapêutico entre janeiro e dezembro de 2005. Os pacientes foram alocados randomicamente em três grupos: um considerado controle e dois grupos de intervenção. O primeiro (ALONG; n=33) realizou 20 min de alongamentos musculares e 20 min de TENS-sham. O grupo intervenção 1 (TENS; n=31) realizou 20 min de falsos alongamentos musculares e 20 min de TENS acupuntural. O grupo intervenção 2 (ALONG/TENS; n=31) realizou 20 min de alongamentos musculares e 20 min de TENS acupuntural. Dos 95 pacientes estudados, 57,9% eram mulheres e 42,1%, homens, com similar distribuição nos 03 grupos (Teste qui-quadrado, P=0,622). Quanto à localização, 32,6% apresentavam dor na região cervical, 2,1% na região torácica, 49,5% em região lombar e 15,8% na região cérvico-lombar (Teste qui-quadrado, P=0,120, para comparação dos 3 grupos). A idade variou dos 19 aos 76 anos, sem diferença entre os grupos (ANOVA, P=0,456). Observou-se que, ao longo das 05 sessões, houve redução significativa dos escores de dor. Porém não foi detectada diferenças entre os regimes terapêuticos estudados. Na avaliação inicial em escala analógica visual, os grupos ALONG, TENS e ALONG/TENS apresentaram, respectivamente, escores (média + desvio padrão) de 53,85+24,18, 57,39+23,47 e 47,74+24,95 (ANOVA, P=0,288). Após 05 sessões, os valores foram, respectivamente, de 25,88+22,62, 27,48+21,47 e 20,39+20,98 (ANOVA, P<0,000 diferença significativa entre os tempos e P= 0,535 diferença não significativa entre os grupos). Na avaliação inicial em escala verbal, os grupos ALONG, TENS e ALONG/TENS apresentaram, respectivamente, escores (mediana, percentis 25% e 75%) de 4(3/4), 4(4/5) e 4(3/4) (Teste de Kruskal-Wallis, P=0,217). Após 05 sessões, os valores foram, respectivamente, de 3(1/3), 3(2/3) e 3(0/3) (Teste de Friedman P=0,000 diferença significativa ao longo do tempo). Concluiu-se que as técnicas de alongamento e TENS são capazes de reduzir significativamente dores musculares com origem na coluna vertebral. Seus efeitos são similares, sugerindo igual eficácia analgésica. / Pain is a common symptom in several situations. It is probably the most frequent reason for the search of medical care. It is estimated that ten to twenty percent of the adult population suffer from chronic pain and that five percent show little response to treatment. The clinical approach to chronic muscular pain must be multidisciplinary, trying to interrupt the pain cycle. With that in mind, many techniques are used, such as muscular stretching, and transcutaneous electrical nerve stimulation (TENS). This research project aimed to evaluate analgesic response to stretching and/or TENS in five physiotherapy sessions for chronic pain in muscles of the spinal cord. A randomized, double-blind, parallel-group, stretching-controlled clinical trial was conducted at Centro Corpo in Porto Alegre, RS, Brazil. Patients with muscular pain in the spinal cord were studied. All of them were adults, with diagnosis of pain lasting for more than six months. The diagnosis was made by an orthopedist and the patients were beginning physiotherapeutic treatment between January and December, 2005. The patients were randomly divided in three groups: one of them was the control group and the other two were the intervention groups. The first group (STRETCH, n=33) did twenty minutes of muscular stretching and twenty minutes of sham TENS. Intervention group one (TENS, n=31) did twenty minutes of ineffective stretching exercises and twenty minutes of Acupuncture TENS. Intervention group two (STRETCH/TENS, n=31) did twenty minutes of effective stretching exercises and twenty minutes of Acupuncture TENS. From the 95 patients analyzed, 57.9% were women and 42.1% were men. They were similarly distributed along the three groups (Chi-square test, P=0.622). As to the region the pain was located, 32.6% presented cervical pain, 2.1% presented thoracic pain, 49.5% had lumbar pain, and 15.8% had cervical/lumbar pain (Chi-square test, P=0.120, to compare the three groups). Age ranged from 19 to 76, with no difference among the groups (ANOVA, P=0.456). It was observed that, throughout the five sessions, there was significant reduction of pain scores. No difference was detected, though, among the therapeutic methods which were studied. In the first evaluation using the Visual Analogical Scale, the groups showed the following scores (mean ± standard deviation): STRETCH: 53.85±24.18, TENS: 57.39±23.47, and STRETCH/TENS: 47.74 ±24.95 (ANOVA, P=0.288). After five sessions, the scores were: STRETCH: 25.88±22.62, TENS: 27.48±21.47, and STRETCH/TENS: 20.39±20.98 (ANOVA, P<0.000; significant difference among the times and P=0.535; no significant difference among the groups). In the first evaluation using the Verbal Scale the groups showed the following scores (median, 25 and 75 percentiles): STRETCH: 4 (3/4), TENS: 4 (4/5), and STRETCH/TENS: 4 (3/4) (Kruskal-Wallis test, P=0.217). After five sessions, the scores were: STRETCH: 3 (1/3), TENS: 3 (2/3), and STRETCH/TENS: 3 (0/3) (Friedman test, P=0.000 significant difference over time). It is concluded that the stretching and the TENS techniques can significantly reduce muscular pain originated in the spinal cord. Their effects are similar, which suggests equal analgesic efficacy.

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