Dissertations / Theses on the topic 'Skin elastic'

Due to the immuncompromised status of AIDS patients, secondary infections and malignancies are common. Conditions secondary to AIDS for which patients require treatment include Karposi's sarcoma (treated with methotrexate), varicella-zoster (treated with antivirals such as acyclovir) and herpes simplex (also treated with antivirals like acyclovir or idoxuridme). However the clinical efficacy of these drugs is limited by poor skin permeability. Few reports, however, have dealt with the delivery of low molecular weight hydrophilic drugs from these vesicles (El Maghraby et al, 2000). The aim of our study was to investigate in vitro permeation of methotrexate, acyclovir and idoxuridine across human epidermal membrane from elastic liposomes. The intent was to establish whether formulation of these hydrophilic drugs into elastic liposomes would enhance their skin permeation parameters. We developed and validated high-performance liquid chromatographic techniques for quantitative analysis of methotrexate, idoxuridine and acyclovir. Elastic liposomes were prepared from various phospholipids- phosphatidylcholine 78.6%; phosphatidylcholine 50%; hydrogenated phosphatidylcholine 90%; phosphatidylcholine 95% and surfactants - sodium cholate, sodium deoxycholate, Span 20, 40, 60, 80. These vesicles were characterised by transmission electron microscopy. The solubilities of methotrexate, acyclovir and idoxuridine were determined. Phospholipon G (95% phosphatidylcholine) was chosen for the preparation of the liposomes with different surfactants. Permeation of methotrexate, acyclovir and idoxuridme from these vesicles across human epidermal membrane was investigated. Flux values for methotrexate, acyclovir and idoxuridine values (J) obtained by curve-fitting of data using Easyplot were compared to those obtained by linear regression. We used Student's t-test to determine statistically significant differences in the flux values of the formulations. A computer program http://www.physics.csbsju.edu/stats/ttest- bulk-form.html was used for this purpose. Our results indicate that there are no statistically significant differences between flux values from elastic liposomes and saturated aqueous solutions.
Thesis (Ph.D. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2004.

Ageing tissue is characterised by an alteration in mechanical properties, with tissues becoming increasingly fragile, stiff and less resilient over time. This can lead to a loss of function in tissues which undergo a high degree of stretch and recoil, such as the skin, blood vessels and lungs. These changes are attributed to remodelling of the dermal extra cellular matrix (ECM) proteins which endow tissue with its mechanical properties. Principally the fibrillar collagens provide tensile strength, complemented by the elastic fibres which confer resilience and allow tissues to recoil following deformation. Intriguingly, at the time of menopause, which sees the cessation of the majority of circulating estrogen, skin undergoes accelerated ageing. This strongly suggests a direct link between circulating estrogen and youthful skin. Using an ovariectomised (Ovx) mouse model of human menopause the link between ageing, estrogen deficiency and the dermal ECM proteins was explored. Mechanical testing revealed a significant reduction in the tensile strength, Young’s modulus and stress relaxation time of estrogen deprived tissue, indicating postmenopausal skin would be weaker, more lax and less able to withstand sustained force. Corresponding histological analysis highlighted the elastic fibres are dramatically reduced by estrogen deprivation with seemingly little effects on the fibrillar collagen abundance or alignment. Direct comparison between Ovx and age, reveals age affects mechanical properties in a completely opposing way, with aged tissue higher in tensile strength, Young’s modulus and stress relaxation time compared to control and Ovx. Proteomic analysis by mass spectrometry confirmed elastic fibres to be highly sensitive to estrogen levels. Additionally small leucine rich proteoglycans (SLRP’s) were also significantly reduced by estrogen deficiency, which could affect collagen fibrillogenesis and leave tissue weaker and more susceptible to damage. Despite the opposing effects on mechanical properties, ageing and estrogen deficiency had comparable effects on ECM abundance, suggesting the amount of ECM is not a predictor of mechanical properties; however disparity may be in part due to increased advanced glycation end product crosslinking. Further investigation suggests the mechanism for elastic fibre degradation may be via significant subcutaneous adipose hypertrophy and/or increased gelatinase activity. Both estrogen replacement and stimulation of estrogen receptor α with the agonist 2,3-bis(4-hydroxyphenyl)-propionitrile (PPT) were found to prevent elastic fibre degradation and adipose hypertrophy. Additionally these treatments were also found to induce key elastic fibre proteins in both the mouse model and cultured human dermal fibroblasts. A deeper understanding of estrogen mediated ECM remodelling offers opportunities for targeted pharmacological intervention to slow the effects of menopause and ageing.

COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
Apesar do conhecimento do comportamento de estruturas sobre base elástica ser importante para a engenharia de forma geral, a motivação deste trabalho está focada na Biomecânica, nos nossos trabalhos envolvendo o grupo de pesquisa da Clínica do Dr.Ivo Pitanguy e da Santa Casa de Misericórdia. Em tese recente de Doutorado, foi realizada uma modelagem da técnica cirúrgica de expansão da pele. A expansão da pele é um processo fisiológico, definido como a capacidade que a pele tem de aumentar sua área superficial em resposta a uma deformação imposta. Durante as expansões acompanhadas pode- se observar que dependendo da região em que o expansor é implantado seu comportamento pode ser bastante distinto. Expansores que são implantados no couro cabeludo iniciam a expansão da pele assim que é introduzida a solução salina no expansor. Quando o expansor é implantado em regiões com mais gordura, como por exemplo na coxa, a expansão da pele não se inicia imediatamente tendo em vista que o expansor se deforma para dentro, pressionando a gordura (que oferece menos resistência) e não a pele. Este comportamento ocasiona abertura dos pontos na cicatriz e pode chegar a inviabilizar todo o processo de expansão naquela região. Para a simulação do processo de expansão da pele, foi feita a expansão com lençol de borracha e para a base elástica foi usado um conjunto que consistia em uma bexiga elástica preenchida com um material viscoso no seu interior. Este trabalho é pioneiro em investigar tanto numérica quanto experimentalmente o comportamento da expansão de lençóis de borracha sobre base rígida e base elástica, comparando o seu comportamento. Os resultados numéricos e experimentais da expansão do lençol de borracha tiveram uma boa concordância e a análise paramétrica da espessura do lençol de borracha comprovou a importância da obtenção mais precisa da espessura da pele pelos médicos, já que as pressões verificadas são bem diferentes para cada espessura. Foram estudadas diversas equações constitutivas, procurando a que melhor descrevesse o processo da expansão da pele. A formulação do material Neo-Hookeano obteve os melhores resultados para o lençol de borracha. Também foi feito um estudo com a formulação de energia de Delfino para estudar a expansão da pele humana.
Despite the knowledge of the behavior of structures on elastic base being important for the engineering of general form, the motivation of this work is focused in the Biomechanics, in our works involving the group of research of the Clinic of the Dr.Ivo Pitanguy and the Saint Casa de Misericórdia. In recent thesis of Dsc., a modeling of the surgical technique of expansion of the skin was carried through. The expansion of the skin is a physiological process, defined as the capacity that the skin has to increase its superficial area in reply to an imposed deformation. During the expansions it could be observed that depending on the region where the expander is implanted its behavior could be sufficiently distinct. Expanders who are implanted on the head initiate the expansion of the skin immediately when the saline solution is introduced in the expander. When the expander is implanted in regions with more fat, as for example in the thigh, the expansion of the skin does not initiate immediately in view of that the expander is deformed to the inner part, pressuring the fat (that offers little resistance) and not the skin. This behavior causes opening of the points in the scar and can make impracticable the process of expansion in that region. For the simulation the process of skin expansion, it was made an expansion with rubber sheet and a set was used for the elastic base that consisted of a filled elastic bladder with a viscous material in its interior. This work is pioneer in investigating numerical and experimentally the behavior of the rubber sheet expansion on rigid base and elastic base, comparing its behavior. The numerical and experimental results of the expansion of the rubber sheet had a good agreement and the parametric analysis of the thickness of the rubber sheet proved the importance of a precise measure of the skin thickness by the doctors, since the verified pressures are different for each thickness. Diverse constituent equations had been studied, looking the one that better described the process of the expansion of the skin. The formularization of the Neo-Hook material got the best results for the rubber sheet. Also a study with the formularization of energy of Delfino was made to study the expansion of the human skin.

A need for a quantitative method to determine body water level has been identified by a team of Clinical Innovation Fellows at the Centre for Technology in Medicine and Health (CTMH). A reliable way to determine body water level would bring great benefits to the healthcare sector, where no optimal method is available at the time of writing. A possible solution is a sensor that would measure alterations in skin properties due to changes in total body water. CTMH has had an idea of such a sensor, which is evaluated in this work. At an early stage of this evaluation process, it became clear that the research regarding correlations between skin properties and body hydration level was not sufficient to warrant the initiation of a sensor development process. Therefore, the main objective of this thesis became to investigate such correlations. An extensive literature review is presented, from which an experiment was developed. The experiment was performed on four human test subjects and involved measurements of skin thickness and elasticity parameters, before and after a weight loss of 3.2-3.7 % due to dehydration. The results showed clear decreases in skin thickness and indications of alterations in skin distensibility as well as in the skin’s immediate elastic response to applied negative pressure. It could also be seen that skin at different body sites does not respond in the same way - calves showed more distinct results than thighs and volar forearm. The material provided in this thesis encourages further studies of the correlation between the mentioned properties and total body water. If a predictable correlation can be found, a sensor development process could start. A reliable way to determine body water level would bring great benefits to the healthcare sector, where no optimal method is available at the time of writing.
Ett behov av att kvantitativt kunna mäta kroppens vattennivå har identifierats av Clinical Innovation Fellowship vid Centrum för Teknik i Medicin och Hälsa (CTMH). Ett tillförlitligt sätt att mäta kroppens vattennivå skulle gynna hälso- och sjukvården på många sätt då ingen optimal metod är tillgänglig i dagsläget. En möjlig lösning skulle kunna vara en sensor som mäter variationer i hudegenskaper till följd av förändringar i kroppens vattennivå. CTMH har haft en idé om en sådan sensor, vilken utvärderas i detta arbete. I ett tidigt skede av utvärderingsprocessen framkom det tydligt att tillräcklig forskning saknades gällande korrelationer mellan hudens egenskaper och kroppens vattennivå. Det huvudsakliga syftet med detta masterexamensarbete blev därför att undersöka sådana korrelationer. En omfattande litteraturgransking gjordes, och utifrån denna utformades ett experiment. Experimentet utfördes på fyra testpersoner och innefattade mätningar av hudens tjocklek samt elasticitetsparameterar. Dessa utfördes före och efter viktnedgång av 3,2-3,7 % till följd av vattenförlust. Resultaten visade på en tydlig minskning av hudtjockleken samt indikationer på förändringar av hudens tänjbarhet samt dess omedelbara elastiska respons vid pålagt negativt tryck. Det visade sig också att huden inte reagerar på samma sätt på olika kroppsdelar - vader visade tydligare förändringar jämfört med lår och armar. Det material som presenteras i detta examensarbete uppmuntrar till fortsatt utredning av korrelationer mellan de nämnda hudegenskaperna och kroppens vattennivå. Om det går att förutse korrelationer finns det förutsättningar för att påbörja utveckling av en sensor.

In this thesis we examine the behaviour of shells supported by elastic foundations. We begin by critically analysing the existing literature on the study of thin objects such as films, plates, membranes and shells, and we highlight their limitations, validity and present correct formulations when possible. We also do the same for various frictional laws, in particular, Coulomb's law of static friction. Then, we extend the capstan equation to noncircular geometries by modelling membranes supported by rigid foundations in presence of friction. We provide closed-form solutions and compare them to other similar existing models in the literature. Then, we begin the study of shells supported by elastic foundations. We treat the bonded case as a boundary form and prove the existence and the uniqueness of solutions, and thus, prove it is a mathematical theory and not merely a mathematical model. To conclude this case we conduct numerical experiments and compare the results against existing models in the literature. Finally, we introduce a constraint and assert that this condition is analogous to classical frictional laws. This constraint is then used to model shells supported by elastic foundations with friction. As with the previous case, we again prove the existence and the uniqueness of solutions, and conclude by conducting numerical experiments and comparing the results against existing models in the literature. Applications for our work can be found in cable drive electronic systems, curvilinear stretchable electronics and modelling skin abrasion.

Introdução: A luz intensa pulsada(LIP) tem sido muito utilizada no tratamento do fotoenvelhecimento sem completo conhecimento de seu mecanismo de ação. Métodos: Foram acompanhados 26 pacientes apresentando fotoenvelhecimento grau II-III (GLOGAU, 1994), os quais foram submetidas à avaliação clínica , histológica e imunoistoquímica 6 e 12 meses após o término do tratamento com LIP. Foram realizadas cinco sessões com intervalos de trinta dias. Além da quantificação histomorfométrica das fibras colágenas e elásticas na derme, foram avaliados CD1, CD4, CD8 e ICAM-1. Resultados: Após 6 meses houve melhora clínica moderada e intensa em 76,92% dos casos e a nota média de satisfação foi 8,57 correspondendo à melhora moderada. Após 12 meses do término do tratamento observou-se que 51,52% das pacientes apresentaram uma melhora clínica moderada em relação à clínica inicial. Os efeitos colaterais foram eritema (11/26), edema (10/26), ardência (7/26) e crostas (8/26). A quantificação das fibras colágenas mostrou aumento médio de 51,33% proporção média de fibra colágena na derme após 6 meses de tratamento e o aumento em relação a 12 meses do término do tratamento foi 30,17%; as fibras elásticas mostraram aumento de 44,13% após 6 meses e aumento de 143,19% após 12 meses do término do tratamento. Na análise imunoistoquímica não houve alteração de CD1 e CD8. Em relação ao CD4 houve redução significante após 12 meses do término do tratamento. Quanto ao ICAM-1 houve aumento em 6 meses com retorno aos níveis normais após 12 meses do término do tratamento. Conclusão: A melhora clínica observada foi comprovada pelo estudo histopatológico, que mostrou aumento das fibras colágenas e elásticas na derme. Após 12 meses do término do tratamento observou-se discreta redução do aspecto clínico da pele correlacionado ao histopatológico. Poucos efeitos colaterais foram observados, sendo todos reversíveis. Desta forma, a LIP constitui boa opção de tratamento para o fotoenvelhecimento cutâneo, sendo uma técnica não ablativa, segura e eficaz.
Introduction: The intense pulsed light has been used in the treatment of photoaging without full knowledge of its mechanism of action. Material and Methods: 26 patients were followed-up presenting photoaging grade II-III (GLOGAU, 1994), who were submitted to clinical evaluation, histological and immunohistochemistry 6 and 12 months after the treatment termination with LIP. Five sessions were made with 30-day intervals. In addition to histomorphometric quantification of collagen and elastic fibers in the dermis, CD1, CD4, CD8 and ICAM-1 were evaluated. Results: After 6 months there were moderate and intense clinical improvement on 76.92% of the cases and the mean score of satisfaction was 8.57 corresponding to moderate improvement. After 12 months of the treatment termination, it was observed that 51.52% of the patients presented a moderate clinical improvement in relation to initial clinic. The side effects were erythema (11/26), edema (10/26), burning (7/26) and crusts (8/26). The quantification of collagen fibers has shown mean increase of 51.33% in the dermis after 6 months of treatment and the increase regarding to 12 months of the treatment termination was of 30.17%; the elastic fibers has shown an increase of 44.13% after 6 months and increase of 143.19% after 12 months of the treatment termination. In the immunohistochemistry analysis there was no alteration of CD1 and CD8. In relation to CD4, there was a significant reduction after 12 months of treatment termination. Regarding the ICAM-1, there was an increase in 6 months with return to normal levels after 12 months of treatment termination. Conclusion: The observed clinical improvement was verified by the histopathologic study, which showed increase in the elastic and collagen fibers in the dermis. After 12 months of treatment termination, it was observed a discrete reduction of clinical aspect of skin correlated to histopathology. A few side effects were observed, being all reversible. Thus, LIP constitutes good option of treatment for skin photoageing, being a non-ablative, safe and effective technique.

La peau et son vieillissement sont un enjeu de santé publique. Les modèles expérimentaux disponibles pour l'étude du vieillissement cutané restent perfectibles. Dans ce contexte, nos objectifs étaient simultanément d'utiliser les modèles de peaux reconstruites (PR) développés dans notre laboratoire afin i) de mieux comprendre les mécanismes du vieillissement cutané, ii) de démontrer l'efficacité et le mécanisme d'action du sélénium comme « anti âge » et enfin iii) de les faire évoluer en utilisant le support poreux ou auto-assemblé avec des fibroblastes du même donneur prélevés à des âges différents. Ainsi, le modèle de PR cultivé sur une longue période a montré une surexpression du microARN miR30-a par RT qPCR dans les PR « âgées » avec une altération de la fonction barrière mesurée par la perte insensible en eau et une perturbation de la différenciation terminale (baisse d'expression de la loricrine et de l'involucrine). Avec le même modèle in vitro, nos résultats démontrent que la supplementation en sélénium retarde la sénescence des kératinocytes souches. Cette efficacité passe non pas par un effet antioxydant comme attendu mais par l'activation de leur adhésion à la lame basale, qui participe à les conserver souche et donc à préserver le renouvellement épidermique. Enfin, nous avons eu la chance exceptionnelle de préparer des PR avec des fibroblastes provenant d'un donneur unique prélevé à 36 et 72 ans. Les résultats immunohistologiques montrent que l'âge induit une augmentation de l'expression de l'élastine et de la fibrilline ainsi que leur co-expression. L'augmentation de LTBP1 et aSMA suggère que cette augmentation inattendue est due à une dérégulation de la voie TGF-ß et une différenciation des fibroblastes en myofibroblastes. En conclusion l'utilisation de différents modèles de PR a permis d'explorer les mécanismes conduisant au vieillissement cutané et de démontrer l'efficacité du sélénium comme anti âge
Skin and its aging is a public health issue. In vitro skin models available for the study aging remain perfectible. In this context, our objectives were simultaneously to use skin equivalent (SE) developed in our laboratory i) to better understand mechanisms of skin aging, ii) to demonstrate the effectiveness of selenium as “anti-aging” and finally iii) to improve SE using the porous or scaffold free model with fibroblasts from the same donor at different ages. Thus, the model of SE mimicking senescence showed an overexpression of microRNA miR30-a by RT qPCR in old SE with an alteration of the barrier function measured by the transepidermal water loss and a deficiency of epidermal terminal differentiation (decreased expression of loricrin and involucrin). With the same SE model, our results demonstrate that selenium supplementation delays the senescence of keratinocytes stem cells. This effectiveness does not involve antioxidant effect as expected but the activation of their adhesion to the basement membrane, which participates in preserving stemness and epidermal renewal. Finally, we had the opportunity to prepare SE with fibroblasts from a single donor at 36 and 72 years old. The histological results show that age induces an increase in the expression of elastin and fibrillin as well as their co-expression. The increase of LTBP1 and aSMA suggests that this unexpected increase is due to deregulation of the TGF-ß pathway and fibroblasts differentiation into myofibroblasts. In conclusion, the use of different models of SE helps us to explore some mechanisms leading to skin aging and to demonstrate the efficacy of selenium as “anti-aging”

L’incidence des cancers cutanés est en constante progression. Leur diagnostic précoce et leur caractérisation in vivo constituent donc un enjeu important. Une approche multimodale et non invasive en spectroscopie fibrée résolue spatialement a été implémentée. L’instrumentation développée permet des mesures co-localisées en multiple excitation d’AutoFluorescence (AF, 7 pics entre 360 et 430 nm) et en Réflectance Diffuse (RD, 390 à 720 nm) résolues spatialement à 5 distances inter-fibres (entre 271 et 1341 µm). Le protocole expérimental a porté sur les stades précoces de cancers cutanés UV-induits sur un modèle pré-clinique. L’analyse histopathologique a permis de définir 4 classes de référence de tissus cutanés : Sain (S), Hyperplasie Compensatoire (HC), Hyperplasie Atypique (HA) et Dysplasie (D), menant à 6 combinaisons de paires histologiques à discriminer. Suite au prétraitement des spectres bruts acquis, puis à l’extraction, la sélection et la réduction de jeux de caractéristiques spectroscopiques, les performances de trois algorithmes de classification supervisée ont été comparées : k-Plus Proches Voisins, Analyse Discriminante Linéaire et Machine à Vecteur de Support. Différentes modalités ont également été évaluées : mono-excitation d’AF seule, Matrices d’Excitation-Emission en AF seules (EEMs), RD seule, couplage EEMs – RD et couplage EEMs – RD résolue spatialement. L’efficacité finale de notre méthode diagnostique a été évaluée en termes de sensibilité (Se) et de spécificité (Sp). Les meilleures résultats obtenus sont : Se et Sp ≈ 100% pour discriminer HC vs autres ; Sp ≈ 100% et Se > 95% pour discriminer S vs HA ou D ; Sp ≈ 74% et Se ≈ 63% pour HA vs D
The incidence of skin cancers is steadily increasing. Their in vivo early diagnosis and characterization is an important issue. An approach noninvasive: the spatially resolved multi-modality spectroscopy has been implemented. The instrumentation developed allows to co-localized measures in multiple AutoFluorescence excitation (AF, 7 peaks between 360 and 430 nm) and Diffuse Reflectance (DR, 390 to 720 nm) spatially resolved at 5 inter-fiber distances (between 271 and 1341 μm). The experimental protocol was focused on the early stages of skin cancer UV-induced in a preclinical model. Four reference classes were defined based on the histopathological analysis of the skin samples: Healthy (H), Compensatory Hyperplasia (CH), Atypical Hyperplasia (AH) and Dysplasia (D), leading to 6 combinations of class pairs to be discriminated. After preprocessing of the raw spectra, extraction, selection and reduction of the most discriminative spectroscopic data set were performed. Then, the efficacy of three supervised classification algorithms was compared: k-Nearest Neighbors, Linear Discriminant Analysis and Support Vector Machine. The contribution of the different modalities was also evaluated: single AF excitation alone, Excitation-Emission Matrices AF (EEMs) alone, DR alone, coupling of EEMs and RD, coupling of EEMs and DR with spatial resolution. The final efficiency of our diagnostic method was evaluated in terms of sensitivity (Se) and specificity (Sp). The best results obtained are: Se and Sp ≈ 100% for discriminating CH vs others; Sp ≈ 100% and Se> 95% for discriminating AH or D vs H; Sp ≈ 74% and Se ≈ 63% to discriminate AH vs D

A terapia fotodinâmica (TFD) atualmente é considerada uma modalidade terapêutica no fotoenvelhecimento, pois apresenta resposta satisfatória tanto no resultado estético como no tratamento e prevenção das lesões pré-malignas que geralmente acompanham a pele fotoenvelhecida. A destruição seletiva do tecido alvo ocorre através de uma reação química, onde se utiliza um agente fotossensibilizante que é exposto a uma determinada luz com comprimento de onda e na presença de oxigênio produz oxigênio \"singlet\" que é responsável pela citotoxicidade das células proliferativas e conseqüente morte celular. Foram estudadas 13 pacientes com fotoenvelhecimanto clínico que foram submetidas a três sessões de TFD-ALA tópico associado à luz vermelha (630nm) com intervalo quinzenal. Após 21 dias da ultima aplicação 12 pacientes apresentaram melhora do fotonvelhecimento; principalmente na coloração e textura da pele, clareamento das lesões de melanose solar, regressão da queratose actinica e melhora da flacidez. Houve também aumento do tecido colágeno e fibra elástica nas colorações de picrosirius e Weigert-oxona respectivamente. Em relação a modulação do sistema imune houve diminuição da população de linfócitos CD4 e CD8, aumento da interleucina-4 na epiderme e derme, diminuição da TNFα na epiderme e aumento na derme.A população de células de Langerhans e o INFγ não apresentaram alterações. A TFD-ALA associada à luz vermelha se mostrou eficaz no tratamento do fotoenvelhecimento clínico, no aumento do colágeno e fibras elásticas e na modulação do sistema imunológico.
PDT is nowadays considered one of the therapies for photo-aging, since it gives a satisfactory response for both, aesthetic result as well as treating and preventing pre-malignous lesions that are a frequent outcome of photo-aged skin. The selective destruction of target tissue occurs through a chemical reaction, by using a photosensitizing agent exposed to a certain light with a wave length which, in the presence of oxygen, produces singlet oxygen responsible for the citotoxidity of the proliferative cells and consequent cellular death. Thirteen pacients with clinical photo-aging have been studied, submitted to three sections of topic ALA-PDT associated with red light (630nm) at fortnight?s intervals.After 21 days of the last treatment, 12 patients showed improved photo-aging, specially regarding skin colour and texture, whitening of the solar melanosis lesions, regression of actinic cheratosis and improvement of flacidity. There also occured an increase of colagenous and elastic fibre tissue in the picrosirius and Weigert-oxona methods respectively.. Regarding the modulation of the immune system, there was a decrease of the lymphocytes CD4 and CD8 population, an increase of interleucin-4 in the epidermis and in the dermis, decrease of TNF-α in the epidermis and increase in the dermis. The Langerhans cells poulation and the INF-γ did not present alterations. The ALA-PDT associated to red light was effective for the treatment of clinical photo-aging, for colagenous and elastic fibres increase and in the imune system modulation.

Abstract Numerous adverse effects and health problems are associated with smoking, but the mechanisms of the adverse effects of smoking on skin are not well documented. The aim of the present study was to elucidate the effects of smoking on the structure, metabolism and appearance of skin. The study population consisted of 98 Finnish males, of whom 47 were current smokers and 51 non-smokers. The main parameters under evaluation were the appearance and physical qualities of skin, including skin wrinkling, thickness and elasticity. Biochemical analyses were performed to assess the rate of type I and III collagen biosynthesis as well as the degradation of the extracellular matrix (ECM) of skin in terms of matrix metalloproteinase levels (MMPs). To compare the morphology of skin between the groups, histological and immunohistological studies were performed, including assessments of the proportional area and width of dermal elastic fibres. The results revealed decreased synthesis of type I and III collagens in smokers as well as changes in the regulatory mechanisms which control the turnover of these and other extracellular matrix proteins. The level of matrix metalloproteinase -8 (collagenase-2), a protease degrading both type I and type III collagen, in suction blister fluid was significantly higher in smokers, indicating enhanced degradation of these collagens. In skin tissue samples, the levels of the active forms of MMP-8 and MMP-9 were significantly lower in smokers compared to non-smokers. Serum levels of MMP-8 were slightly but not significantly higher in smokers, whereas the levels of the matrix metalloproteinases MMP-2 and MMP-9 (72-kDa and 92-kDa gelatinase, respectively) were significantly higher in smokers compared to non-smokers. Salivary MMP-8 and MMP-9 were lower in smokers compared to non-smokers, but only the latter showed a statistically significant difference. The levels of the tissue inhibitor of matrix metalloproteinases (TIMP-1) were significantly lower in the suction blister fluid of smokers compared to non-smokers. In general, there were no significant differences in skin thickness and elasticity or regeneration of barrier function, nor in the amount or width of elastic fibres between the groups. We did not observe significant differences in skin wrinkling between smokers and non-smokers, but smokers looked older than their age compared to non-smokers. It can be concluded that the rate of type I and III collagen synthesis in skin is decreased and the regulation of ECM turnover is altered in smokers, which may lead to deterioration of the tensile strength and resiliency of skin in the long term, even though no morphological changes were detected in the present study.

O aumento da prevalência da obesidade mórbida constitui um problema de saúde pública global. A obesidade mórbida pode ser definida por um índice de massa corpórea ( IMC ) superior a 35 Kg/ m²; vem acompanhada por diversas comorbidades e determina custos sócio-econômicos elevados. O único método efetivo a longo prazo no tratamento da obesidade mórbida, na atualidade, é a cirurgia bariátrica. Os procedimentos cirúrgicos para tratar a obesidade foram estimulados sobretudo pelo advento de técnicas videolaparoscópicas com menor morbidade pós-operatória e recuperação precoce. O sucesso operatório da cirurgia bariátrica representa perda de até 50% do excesso de peso dos pacientes em prazos variáveis de aproximadamente 24 meses. Após tal período, o processo de emagrecimento será refletido como excesso e flacidez cutânea generalizados e inicia-se a busca pela melhora da imagem corporal. A realização das cirurgias plásticas de contorno corporal exige ampla compreensão das peculiaridades clínicas desse paciente, e dos riscos de complicações, além de expectativas viáveis quanto aos resultados estéticos. Após as cirurgias de contorno corporal, passado o período pós-operatório recente, constata-se a manutenção de flacidez cutânea residual em graus variados. A obesidade interfere na qualidade dos componentes da pele humana. Entretanto, não há estudos específicos em relação à pele do paciente após perda ponderal maciça. Nesse estudo observacional histomorfométrico realizado entre 2006 e 2008, o autor avalia em biópsias de pele humana da região abdominal epigástrica e hipogástrica, o teor de colágeno e elastina em pacientes após perda ponderal maciça comparativamente a pacientes sem antecedentes de obesidade. Analisando a pele abdominal de mulheres não obesas ( controles epigástricos=15 e controles hipogástricos=25 ) e mulheres após tratamento dessa morbidade ( casos=40), verificou-se neste estudo com significância estatística aceita como p<0,05 que: a) na região epigástrica, o teor de colágeno foi superior no grupo controle em comparação ao grupo de casos; b) na região epigástrica, o teor de fibras elásticas foi superior nos casos; c) na região hipogástrica, não houve diferença estatisticamente significante no teor de colágeno entre os grupos estudados; d) na região hipogástrica, o teor de fibras elásticas foi superior no grupo controle
Morbid obesity is an increasing health problem and it is defined as a body mass index greater than 35 kg/m² with severe obesity related comorbidity or a body mass index greater than 40 kg/m² without comorbidity. The combined direct and indirect cost of obesity has been elevated. Bariatric surgery remains the only durable option for weight loss in the morbidly obese.Advanced laparoscopy procedures, as less invasive therapy, have contributed to fast recovery and acceptable perioperative morbidity. Results of bariatric surgery can reach about 50% of excess weight loss with a 2 year follow-up. As patients lose weight, they get laxity skin and their interest in body contouring surgery begins.Plastic surgery in massive weight loss patient demands attention to reduce risks and viable expectations concern to aesthetic results. However, after body contouring surgery, patients can keep up some laxity or folds of excess skin. Obesity changes the components of skin, but there arent definitive studies about skin in massive weight loss patients. In this histomorphometric comparative study, biopsies of human female abdominal skin were analysed in quantity of collagen and elastic fibers in controls (non obese patients, epigastric topography n=15 and hypogastric topography n=25 ) in comparison to massive weight loss patients (n=40). After statistical analyses with p<0,05 was demonstrated that: a)in epigastric topography, the quantity of collagen was higher in control group; b) in epigastric topography, the quantity of elastic fibers was higher in case group; c) in hypogastric topography, there werent diferences in the quantity of collagen between cases and controls; d) in hypogastric topography, the quantity of elastic fibers was higher in control group

One-nucleon halo nuclei are exotic nuclei which can be seen as a core around which orbits a loosely-bound valence nucleon. They are usually studied through reactions such as elastic scattering and breakup. The ratio method has been developed as a tool to study one-neutron halo nuclei at high energies. It consists of the ratio of angular cross sections, breakup and elastic scattering, which removes most of the sensitivity to the reaction mechanism and to the reaction model. In the simple recoil excitation and breakup (REB) model, the ratio simplifies to a form factor dependent solely on the wave function of the projectile. By measuring this observable and comparing it to the REB form factor, i.e. in the ratio method, more detailed information on the structure of the halo could be obtained. For neutron-halo nuclei at high energy, the ratio observable obtained from accurate CDCC and DEA theoretical calculations follows its REB prediction. I study the extension of this method to lower energies of the reaction which could make the measurement appropriate to facilities such as SPIRAL2 (GANIL, Caen, France) and ReA12 at FRIB (Michigan State University) and to proton halos. This is done by comparing the REB form factor to dynamical calculations of the ratio. The reactions investigated are the reaction of 11Be, the archetypical one-neutron halo nucleus, on 12C, 40Ca and 208Pb targets at 20 MeV/nucleon and of 8B, the archetypical one-proton halo nucleus, on 12C, 58Ni and 208Pb targets at44 MeV/nucleon.For these reactions, the adiabatic assumption is no longer valid due to the effect of the Coulomb interaction. This effect is mainly visible at forward angle for 11Be and is aggravated for 8B by the fact that the halo is charged. The ratio works less well than for neutron-halos at intermediate and high energies. Nevertheless, the ratio is shown to be very sensitive to the orbital angular momentum l0 in which the halo is bound and its binding energy E0, i.e. the single-particle structure of the projectile. Variations of l0 and E0 induce visible changes in shape and in magnitude (up to several orders) of the ratio. Also, the agreement of the ratio with its REB prediction is best when the projectile is loosely-bound and for low l0, i.e. for s and p waves. The validity of the method is not affected by the use of energy ranges—or bins— in the projectile continuum. These tend to increase the cross section without changing the agreement of the ratio with its REB prediction. The applicability of the method is finally explored at high energy for proton-rich nuclei 17F, 25Al and 27P. I show that the ratio method works the latter since this nucleus is bound by a mere 0.870 MeV in the s-wave. For the other nuclei, although the agreement of the ratio with its REB prediction is less good than for neutron-halo nuclei at high energy, it still provides estimates of nuclear-structure features, such as l0 and E0 and could be applied in what can be called an approximate application of the ratio method. Heavy nuclei exhibit a neutron skin, i.e. a thin layer around the nucleus where only neutrons are found. The thickness of the skin is highly correlated with the slope of the symmetry energy. The process of coherent neutral-pion photoproduction is used to extract the nuclear density and hence the neutron-skin thickness of heavy nuclei. In order to analyse recent data on the photoproduction on 12C, 40,48Ca, 116, 120, 124Sn and 208Pb, I build a reaction code. My model uses the formalism of Kerman, McManus and Thaler (KMT) which allows to build the photoproduction matrix on a nucleus from the ones describing the elementary process on a single nucleon. Within the impulse approximation, the photoproduction is seen as the coherent sum of the photoproduction on each of the nucleons. In the plane wave impulse approximation (PWIA), no rescattering of the pion is considered after its production and the cross section is directly proportional to the Fourier transform of the density. Such process is taken into account at the distorted wave impulse approximation (DWIA) by considering a potential simulating the pion-nucleus interaction and built from the KMT formalism.The agreement of my model with the data is good, especially for 208Pb. The distortion has a significant impact on the photoproduction process. The sensitivity of the process to the density of the target is analysed by performing the calculations with several different densities calculated in different structure models. The distortion has the effect of deteriorating this sensitivity. In the particular case of a 208Pb target, the impact of variations of the neutron-skin thickness of around 0.1 fm on the photoproduction cross section is ten times smaller than the size of the error bars on the experimental data. These results, although less dramatic, hold for the tin targets, for which preliminary data exists. In the light of these results, the coherent neutral-pion photoproduction process does not seem to be suited in the study of the neutron-skin thickness. This conclusion goes in contrast to the results of recent measurements on 208Pb, for which the method was shown to be sensitive to fine details of the density.
Doctorat en Sciences de l'ingénieur et technologie
info:eu-repo/semantics/nonPublished

Pacientes submetidos ao tratamento cirúrgico da obesidade mórbida apresentam perda ponderal acentuada e dismorfismo corporal e, com frequência, solicitam cirurgias plásticas visando um contorno corporal mais adequado. Os resultados dessas cirurgias plásticas são, em parte, limitados pela qualidade da pele resultante do grande emagrecimento. O presente estudo observacional teve como objetivo comparar fragmentos de pele da região epigástrica de 20 pacientes após perda ponderal acentuada consequente à cirurgia bariátrica com 20 pacientes portadores de obesidade mórbida, no sentido de analisar as alterações estruturais da pele como consequência do emagrecimento. A análise histomorfométrica foi realizada sobre o sistema colagênico através da metodologia Picrossírius/luz polarizada, e sobre o sistema elástico através da metodologia resorcinafucsina de Weigert. Foram observados, a redução das fibras colagênicas grossas (p=0,048); o aumento das fibras colagênicas finas (p=0,0085); e o aumento da densidade das fibras elásticas (p=0,0000009033) no grupo de pacientes emagrecidas. Não houve diferença entre os grupos quanto à média de idades (p=0,917) e quantidade total de fibras colágenas (p=0,3619). Os resultados evidenciaram as alterações estruturais da derme decorrentes do emagrecimento acentuado, demonstradas por meio do remodelamento colagênico, com a consequente redução das fibras espessas, organizadas, estruturadas e direcionadas em prol do aumento de fibras finas, desalinhadas e frouxamente dispostas, isso em associação ao aumento da elasticidade da pele. Isto explica cientificamente a já estabelecida percepção clínica das alterações cutâneas dos pacientes emagrecidos após cirurgias bariátricas, apresentando menor resistência e maior flacidez, quando comparadas ao período anterior ao emagrecimento
Post-bariatric patients develop body contour deformities and need plastic surgery procedures for reduction of excess skin and subcutaneous tissue. The results of these contouring procedures are typically limited by the poor quality of the skin. This observational study compared the epigastric skin of 20 post-bariatric with massive weight loss women with 20 women with morbid obesity through histomorphometric analysis of collagen fibers (picrosiriuspolarization) and elastic fibers (Weigert\'s resorcin-fuchsin). A reduction of thick collagen fibers (p=0.048), increase of thin collagen fibers (p=0.0085) and increase of the density of elastic fibers (p=0.0000009) were observed in the group of post-bariatric patients. There was no difference between the groups for mean age (p=0.917) and the total amount of collagen fibers (p=0.3619). These results represent structural changes in the dermis due to the massive weight loss once it demonstrates collagen modifications with reduction of thickness, organized and structured fibers, increase of thin, misaligned and disarranged fibers, and augmentation of the density of elastic fibers. This brings the scientific explanation for the established clinical perception that the skins of post-bariatric patients are less resistant and with more laxity when compared with what they were before the bariatric surgery

Στην παρούσα διπλωματική εργασία μελετάται η συμπεριφορά του ανθρώπινου δέρματος κατά την εφαρμογή σημειακής (κατακόρυφης) δύναμης αλλά και μη σημειακής (επιφανειακής). Για τη μελέτη κατασκευάζεται εικονικό μοντέλο τμήματος του δέρματος με χρήση πεπερασμένων στοιχείων. Στόχος είναι η εισαγωγή του μαθηματικού μοντέλου σε ρομποτικό σύστημα το οποίο θα κάνει ένεση προκαλώντας το λιγότερο δυνατό πόνο ή μασάζ με τη μεγαλύτερη δυνατή αποτελεσματικότητα. Στη διπλωματική δεν προγραμματίζεται κάποιο ρομπότ που να επιτελεί το έργο αυτό, αλλά αναπτύσσεται ο κώδικας σε matlab ο οποίος μετασχηματισμένος θα μπορούσε να χρησιμοποιηθεί από ένα ρομποτικό σύστημα. Αρχικά, αναλύεται η μέθοδος των πεπερασμένων στοιχείων ώστε να επιλεγεί το κατάλληλο μοντέλο για το πρόβλημά μας. Με την παραδοχή ότι υπάρχει αξονική συμμετρία επιλέγεται να χρησιμοποιηθεί μια δομή δύο διαστάσεων αποτελούμενη από δύο στρώματα διαφορετικής ελαστικότητας (υποθετικά, δέρμα και υποδόριος ιστός). Για τη μοντελοποίηση αυτή αναλύονται οι διαδικασίες που πρέπει να ακολουθηθούν και οι παραδοχές που πρέπει να ληφθούν υπ’ όψιν. Επίσης, αναλύεται με μαθηματικό τρόπο η προσέγγιση του προβλήματος παραμόρφωσης σε δύο διαστάσεις. Στη φάση αυτή, ανάπτυξης και επιλογής του βέλτιστου μοντέλου, η προσομοίωση γίνεται εξ' ολοκλήρου σε matlab. Στη συνέχεια, αφού ορισθεί το μοντέλο σε δύο διαστάσεις πρέπει να προσδιοριστούν οι παράμετροι για το σχετικό πάχος των δύο στρωμάτων και τη σχετική τους ελαστικότητα ώστε το μοντέλο να ανταποκρίνεται στην πραγματικότητα. Για να επιτευχθεί η συγκριτική αυτή αξιολόγηση, χρησιμοποιούνται δύο ομάδες πραγματικών πειραματικών τιμών που περιγράφονται σε σχετικές μελέτες διαθέσιμες στη διεθνή βιβλιογραφία. Δοκιμάζονται συγκριτικά διάφορα ζεύγη παραμέτρων με στόχο να γίνει μια ανάλυση ευαισθησίας του μοντέλου, και να εντοπιστεί αυτός ο συνδυασμός τιμών για τον οποίο υπάρχει η ελάχιστη απόκλιση από τα πειραματικά δεδομένα. Τέλος, αξίζει να αναφέρουμε πως στο δεύτερο τμήμα της εργασίας όπου μοντελοποιείται η συμπεριφορά του δέρματος σε μη σημειακή καταπόνηση χρησιμοποιούνται τα ίδια πειραματικά δεδομένα καθώς και δεδομένα από άλλες προσπάθειες μοντελοποίησης. Ο κώδικας που χρησιμοποιείται είναι κατά ένα μεγάλο ποσοστό ίδιος με αυτόν του 1ου μέρους.
The scope of this thesis is the study of the behavior of the human skin surface at the application of a vertical point as well as a non-point force on it. A model of a skin part is developed for the needs of this study, with use of finite elements method. The aim is to introduce the mathematical model in a robotic system which will inject causing the least possible pain or massage with maximum efficiency. In this thesis the robot is not being programmed, but it is been developed the code in matlab which by an appropriate transformation it could be used by the robot. First of all, the finite element method is been analyzed in order to select an appropriate model for our problem. Assuming axial symmetry is chosen to use a two-dimensional structure consisting of two layers of different elasticity (supposedly, skin and subcutaneous tissue). For the modeling the procedures we have to follow and the standards we should take into account are being analyzed. Furthermore we analyze the approach of the problem of deformation in two dimensions mathematically. At this stage, construction and selection of the optimal model, the simulation is entirely in matlab application. Then, after having built the model in two dimensions, the parameters for the relative thickness of both layers and their relative flexibility to the model to reflect reality must be defined. To achieve comparative evaluation, two groups of actual experimental values described in related studies available in the literature. Several pairs of parameters are being tested and compared in order to do a sensitivity analysis of the model, and found this combination of values for which there is little deviation from the experimental data. Finally it is worth mentioning that the second part of the work where the behavior of the skin in non-spot stress is being modeled there are used the same experimental data and data from other modeling efforts. The code used is a large proportion same as the one used in the 1st part.

Elastic fibers are major components of ECM, providing tissues with resilience and elastic recoil. They consist of the insoluble elastin made of cross-linked precursor tropoelastin monomers and the microfibrillar scaffold. Various connective tissue disorders have been linked to elastic fiber malformation. In addition, it has been shown that decreased vascular elastin contents correlate with the rapid progression of atherosclerosis in patients with diabetes mellitus. However, it is unknown whether insulin can directly modulate elastogenesis. This question was addressed in this thesis. Our study revealed that insulin stimulated elastogenesis in cultures of human aortic SMCs and skin fibroblasts, and that this effect of insulin was transduced through the insulin receptor. We found that insulin might initiate elastin gene expression and enhance tropoelastin secretion. We also presented novel preliminary data indicating that Glut10 might bind to a fraction of intracellular tropoelastin, and that insulin might modulate the association between these two proteins.

碩士
國立成功大學
工程科學系碩士在職專班
104
SUMMARY Since the steel industry in the production or maintenance belongs to costly industry category, how to reduce the cost is very important. In the study, the numerical simulation is used to verify the elastic deformation mode of Chung Hung Company's furnace skid. The deformation difference and stress distributions are analyzed under the interaction conditions of different materials, configuations and high levels of pass line. The reasons of the resulting differences are explored and the configuration condition of minimal deformation is found from the study results, which could help to reduce the production and maintenace cost. Key word : Furnace, Skid, Numerical Analysis.

This thesis deals with the design of an anti-skid brake controller for a generic fighter aircraft. Antiskid brake controllers prevent wheel locking and maximize the coefficient of friction between the tyre and the ground, resulting in lower stopping distance and time. The frictional force is maximized by regulating the slip. A model for the landing gear is first developed, which consists of the translational and rotational motions of the wheel, the equation for the slip and the elastic landing gear strut dynamics. The elastic behaviour of the landing gear is characterized through its modal frequencies, obtained from a Finite element analysis. As the governing equations are nonlinear, with linear elastic deformations of the strut, feedback linearization is used to design the anti-skid controller. The brake controller is found to work well. Its stability is verified through numerical simulations. Both the plant parameters and the sensor measurements are perturbed up to 10% from their nominal values. It is seen that the feedback linearization tolerates these variations quite well. The system is exceptionally tolerant to sensor noises. The torsional stiffness of the strut is found to be more critical than the longitudinal stiffness. Limits on the torsional stiffness that can be tolerated by the controller are found. This determines the limits on the stiffness of the landing gear beyond which gear walk may appear. The thesis concludes with suggestions for future work in this exciting field.