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Parthasarathy, Krupa. "Aging Analysis and Aging-Resistant Design for Low-Power Circuits." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1415615574.
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Fox, Bronwyn Louise. "The manufacture, characterization and aging of novel high temperature carbon fibre composites." View thesis entry in Australian Digital Theses Program, 2001. http://thesis.anu.edu.au/public/adt-ANU20011207.114246/index.html.
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Nakamura, Yusuke, Hiroshi Inano, Satoshi Hiroshima, Tatsuya Hirose, Masahiro Hamaguchi, and Hitoshi Okubo. "Partial Discharge Resistant Aging Mechanism of Nanocomposite Enamel Wires under Repetitive Surge Voltage Condition." IEEE, 2008. http://hdl.handle.net/2237/12130.
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Lundberg, Daniel, Filip Wilson, Hjalmar Gunnarsson, Leo Sjörén, Robin Xu, and Erik Djurberg. "Long term aging and creep exposure for advanced heat resistant alloys : A phase analysis." Thesis, Uppsala universitet, Institutionen för materialvetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-446407.
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This project was ordered by Sandvik Materials Technology and was performed by a group of students at Uppsala university. The purpose of the project was to study precipitation behavior and structure stability in six advanced heat resistant alloys. Each sample were subjected to a creep rupture test in 600 or 700°C depending on the alloy type. Two parts of each alloy where examined; one part which had been affected by creep and another part which was unaffected by creep. A literature study was performed first to gain knowledge of the scientific theory utilized in this project, namely creep, precipitation hardening, and about the different materials which were analyzed. Preliminary results for the phase composition of the materials were obtained from a Thermo-Calc (TC) simulation. The SEM-images showed nothing noteworthy for any sample due to the roughness of the sample surfaces. The EDS-analysis showed chromium depletion in the centers of the aged samples of HT9 and Sanicro® 75X. Other minority phases such as Cr23C6 in Sanicro®70, P-phase and a titanium nitride phase in sanicro® 60X, VB in Esshete 1250 and Sigma-phase in 4C54 were identified using EDSmapping. It was found that when using XRD to analyze the phase compositions of small samples it is impractical to have the samples cast in bakelite beforehand. The XRD-results obtained in this project showed that more than 90% of the XRD diffractogram for every sample was graphite, which made the identification of minority phases impossible. The quality of the LOM-images varied greatly between samples, for 4C54 grain sizes were measured in all images, for Esshete 1250 grain sizes were measured for the crept sample, and for Sanicro® 60X measurements could only be taken from one image. Most of the sample preparation was insufficient to achieve the test results necessary for complete microstructural analysis and phase analysis of the samples. The mistakes in the practical steps of the project were noted and improvements for these mistakes are presented in the conclusion.
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Baxter, Christopher David Price. "An Experimental Study on the Aging of Sands." Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/28450.
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There are numerous examples in the literature of time-dependent changes in the proper-ties of sands, or aging effects. Most of these aging effects are of increases in the cone penetration resistance. Time-dependent increases in penetration resistance have been measured in hydraulically placed fills and freshly densified deposits, with the largest in-creases following the use of ground modification techniques such as vibrocompaction, dynamic compaction, and blast densification. It is not known what causes these increases in penetration resistance to occur.
The objective of this research was to gain an understanding of the possible mechanisms responsible for aging effects in sands. Current hypotheses to explain what causes aging effects in sands include increased interlocking of particles, internal stress arching, and precipitation of silica or carbonate minerals at the contacts between grains. To date, no unambiguous evidence has been presented to support these hypotheses. A laboratory testing program was developed to study the influence of different variables on the pres-ence and magnitude of aging effects. Three different sands were tested in rigid wall cells and buckets. Samples were aged under different effective stresses, densities, tempera-tures, and pore fluids. In every rigid wall cell, three independent measurements were made to monitor property changes during the aging process: small strain shear modulus using bender elements, electrical conductivity, and mini-cone penetration resistance. At the end of each test, detailed mineralogical tests were performed to assess changes in the chemistry of the samples and pore fluids. A total of 22 tests in rigid wall cells were per-formed with periods of aging ranging from 30 to 118 days. Mini-cone penetration resis-tances were measured in the buckets before and at various times during the aging process.
Increases in the small strain shear modulus were measured with time. It was found that sand type and pore fluid composition greatly influenced the amount of increase in small strain shear modulus. Density was also found to influence the amount of increase in small strain shear modulus. Temperature was found to have little influence on the in-crease in small strain shear modulus with time.
Changes in the chemistry of the samples were also measured with time. The dissolution and precipitation of minerals in solution was monitored with electrical conductivity measurements. In most of the tests, there was continual dissolution of minerals with time. Mineralogical studies and conductivity measurements indicated precipitation of carbonates and silica in two of the tests; however, scanning electron micrographs showed no visible evidence of precipitation.
Despite the measured increases in small strain shear modulus and evidence of mineral precipitation, there were no increases in the mini-cone penetration resistance with time. This finding is significant and suggests that small-scale laboratory experiments do not capture the mechanism(s) that are responsible for time-dependent increases in penetration resistance in the field.Ph. D.
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Harris, Nicholas Lionel. "Stress resistance and ageing in Saccharomyces cerevisiae." Thesis, University College London (University of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400596.
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Macedo, Tânia Sofia Oliveira. "Improvement of the ageing resistance of 2YSZ ceramic." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/21896.
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Mestrado em Materiais e Dispositivos BiomédicosZirconia is a widely studied ceramic and it is applied in several areas such as engineering (solid oxide fuel cells, thermal barrier coatings) and biomedicine, in areas such as orthopedic and odontology. This material can be applied with the purpose to restore a body function that was compromised by a degenerative disease (orthopedic implants), in dental area and sensors due to its excellent mechanical properties, aesthetic characteristics and biocompatibility. However, this ceramic is sensitive to ageing and has a low hardness. To overcome these limitations, samples of Yttria Stabilized Zirconia doped with different oxides were developed and the goal was to improve the ageing resistance and mechanical properties of un-doped 2 mol% Yttria Stabilized Zirconia (2YSZ). A careful selection of the dopants and respective concentrations was performed. According to the literature, ceria (CeO2), silica (SiO2), alumina (Al2O3), lanthana (La2O3), ytterbia (Yb2O3) and manganese oxide (MnO2) improve the ageing resistance and/or the mechanical properties of Yttria Stabilized Zirconia (YSZ). In this study, thirteen different doped 2YSZ compositions were developed. For each selected dopant, three to four compositions were performed with different dopant concentrations. After a wet milling stage, the doped stabilized zirconia powders were obtained by spray-drying, from stabilized suspensions with a controlled nanometric particle size distribution. The obtained doped sprayed powders were characterized through several techniques, such as scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray fluorescence (XRF), density and specific surface area (SSA). Green bodies of all doped compositions were obtained by uniaxial pressing (70 MPa). High density ceramics (with relative density between 90% and approximately 99%) were achieved at low sintering temperatures (1350 °C and 1400 °C). The grain size of the sintered samples was measured by SEM images, and a dispersed microstructure with a nanometric grain size was observed for all 2YSZ doped samples. The crystallographic phases present in the doped samples were identified by XRD. In order to assess their thermal ageing resistance, the samples were subjected to a thermal treatment at low temperatures (200 °C) during a period of 36 hours. After this treatment, the fracture toughness of the aged samples was evaluated. From all the starting samples, those with better resistance to thermal ageing and fracture toughness were afterwards selected: samples of 2YSZ doped with CeO2 (0.50 wt%) and with SiO2 (0.25 wt%) and La2O3 (1.07 wt%). Cylindrical bodies of the selected doped 2YSZ compositions were obtained by two pressing stages - uniaxial and cold isostatic pressing - and sintered at 1350 ºC for 3 hours. The behaviour of the sintered samples was investigated in terms of hydrothermal ageing resistance, according to the specifications mentioned in ISO 13356:2008 (134 ± 2 ºC and 0.2 MPa), and mechanical properties: Vickers’ hardness along with fracture toughness and flexural strength. The amount of monoclinic zirconia, indicative of degradation, was determined by XRD after 5 hours of ageing test. Afterwards the mechanical behaviour (Vickers hardness, fracture toughness and flexural strength) of the aged samples was assessed. The results obtained in the present study demonstrate that adequate doped 2YSZ samples, with improved hydrothermal degradation resistance (9.87 % of monoclinic zirconia for SiO2 with La2O3 doped 2YSZ sample while un-doped 2YSZ presented a monoclinic phase higher than 15 %) can be obtained. The mechanical properties of the sample of 2YSZ doped with both oxides (SiO2 and La2O3), before and after the hydrothermal ageing, were practically maintained (1159 vs 1141 HV (hardness), 9.68 vs 9.15 MPa.m1/2 (fracture toughness) and 700 vs 698 MPa (flexural strength)). Nevertheless, a decrease of the mechanical properties was observed for both selected doped 2YSZ samples in relation to un-doped sample.
A zircónia é um cerâmico amplamente estudado e aplicado em diversas áreas da engenharia (células de combustível, revestimentos de barreiras térmicas) e biomedicina, em áreas como a ortopedia e a odontologia. Este material tem sido aplicado com o propósito de restaurar funções corporais que foram comprometidas por uma doença degenerativa (implantes ortopédicos), na área dentária e em sensores, devido às suas excelentes propriedades mecânicas, características estéticas e biocompatibilidade. Atualmente, existe a necessidade de desenvolver novos dispositivos com elevadas taxas de sucesso para as aplicações médicas mencionadas. O aumento da longevidade dos dispositivos protéticos para uma população jovem, mais ativa, com maior esperança de vida, requer o desenvolvimento de novos produtos, com desempenhos e designs fiáveis. O uso de Yttria Tetragonal Zirconia Polycrystal (Y-TZP) abriu possibilidades para desenvolver novos e promissores implantes, com novas e mais complexas geometrias, que não eram possíveis com outros cerâmicos, como por exemplo a alumina (mais frágil). Contudo, a zircónia cerâmica apresenta algumas limitações de trabalho: é sensível ao envelhecimento e apresenta baixa dureza. Devido a estas limitações, foram desenvolvidas várias amostras de zircónia estabilizada com 2 mol% de ítria (2YSZ), dopadas com diferentes óxidos, com o objetivo de avaliar e melhorar a resistência ao envelhecimento e propriedades mecânicas, quando comparadas com as amostras não dopadas. Para este efeito, foi realizada uma seleção criteriosa dos dopantes e respetivas concentrações. De acordo com a literatura, a céria (CeO2), sílica (SiO2), alumina (Al2O3), lantana (La2O3), íterbia (Yb2O3) e óxido de manganês (MnO2) melhoram a resistência ao envelhecimento e/ou as propriedades mecânicas da zircónia estabilizada com ítria (YSZ).Neste estudo, foram desenvolvidas treze diferentes composições dopadas, de zircónia estabilizada com 2 mol% de ítria (2YSZ). Por cada dopante selecionado foram preparadas três a quatro composições. Após uma etapa de moagem, os pós dopados de zircónia foram obtidos por atomização, a partir de suspensões estabilizadas, com uma distribuição de tamanho de partícula nanométrico controlado. Os pós atomizados foram caracterizados recorrendo a várias técnicas tais como microscopia eletrónica de varrimento (SEM), difração de raios-X (DRX), fluorescência de raios-X (FRX), densidade real, e área superficial específica (SSA). Os corpos em verde de todas as composições foram obtidos por prensagem uniaxial (70 MPa). Foram obtidos corpos cerâmicos com densidade elevada (com densidade relativa entre 90% e aproximadamente 99%) a uma temperatura de sinterização relativamente baixa (1350 ºC e 1400 ºC). O tamanho de grão das amostras sinterizadas foi medido através de imagens SEM, sendo verificado em todas as amostras de 2YSZ dopadas, uma microestrutura dispersa, com um tamanho de grão nanométrico. As fases cristalográficas presentes nas amostras dopadas foram identificadas por DRX. A fim de avaliar a resistência ao envelhecimento, as amostras sinterizadas foram submetidas a um tratamento térmico a baixas temperaturas (200 ºC) durante um período de 36 horas. Após este tratamento foi avaliada a tenacidade à fratura das amostras envelhecidas. Com base nestes resultados selecionaram-se as amostras que apresentavam melhor resistência ao envelhecimento térmico e tenacidade à fratura: 2YSZ dopada com CeO2 (0.50 wt%) e SiO2 (0.25 wt%) com La2O3 (1.07 wt%). Os pós das composições selecionadas foram sujeitos a prensagem uniaxial seguida de prensagem isostática a frio e sinterizadas a 1350 ºC durante 3 horas. Após sinterização, o comportamento destas amostras foi investigado em termos de resistência ao envelhecimento hidrotérmico e propriedades mecânicas: dureza de Vickers, tenacidade à fratura e resistência à flexão. Os testes de envelhecimento hidrotérmico foram realizados de acordo com as especificações mencionadas na norma ISO 13356:2008 (134 ± 2 ºC e 0.2 MPa). A percentagem de zircónia monoclínica, indicador de degradação, foi determinada por difração de raios-X após 5 horas de teste de envelhecimento hidrotérmico. Posteriormente, avaliou-se o comportamento mecânico (dureza de Vickers, a tenacidade à fratura e resistência à flexão) das amostras envelhecidas. O presente estudo demonstra que podem ser obtidas amostras cerâmicas de 2YSZ dopadas adequadas, com resistência à degradação hidrotérmico melhoradas (9.87 % de zircónia monoclínica para a amostra de 2YSZ dopada com SiO2 e La2O3, enquanto que a amostra de zircónia não dopada apresenta uma percentagem de fase monoclínica superior a 15 %). As propriedades mecânicas da amostra dopada com ambos os óxidos (SiO2 e La2O3), antes e após o envelhecimento hidrotérmico, foram praticamente mantidas (1159 vs 1141 HV (dureza), 9.68 vs 9.15 MPa.m1/2 (tenacidade à fratura) e 700 vs 698 MPa (resistência à flexão)). Porém, uma diminuição das propriedades mecânicas foi observada para ambas as amostras dopadas de 2YSZ selecionadas em relação à amostra de zircónia não dopada.
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Drake, Derek. "REST and the regulation of stress resistance, brain aging, and Alzheimer’s disease." Thesis, Harvard University, 2016. http://nrs.harvard.edu/urn-3:HUL.InstRepos:33493396.
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Understanding how age-related stress in the brain is managed over a lifetime to maintain neuronal and cognitive function and prevent neurodegeneration will be critical for developing therapies to promote healthy aging. Here we show that repressor element 1-silencing transcription factor (REST) is induced in neurons of cognitively-intact aged individuals, but not those with Alzheimer’s disease (AD). REST protects against factors associated with AD, such as neuronal apoptosis and AD neuropathology, through direct binding and repression of pro-apoptotic genes and genes that contribute to AD neuropathology. REST nuclear levels in prefrontal cortex pyramidal neurons also correlate with increased AD age of onset and decreased AD neuropathology. REST protects against toxic insults associated with aging, such as oxidative stress. Moreover, REST regulates FOXO1, a fundamental regulator of the response to oxidative stress, to provide oxidative stress protection. REST and FOXO1 nuclear levels correlate in aging human cortical neurons. Furthermore, REST and FOXO1 expression are correlated with the expression of FOXO1-regulated genes that protect against oxidative stress in aged prefrontal cortex. REST also downregulates miR- 132 and miR-212, microRNAs that repress FOXO1 expression, and sensitize to oxidative stress. High levels of REST in the nucleus correlate with reduced longitudinal cognitive decline during aging. Moreover, REST nuclear levels account for a significant fraction of the variability of cognitive decline in the aging human population by a mixed model analysis. These results suggest that the neuroprotective function of REST is mediated, at least in part, through regulation of FOXO1 and miR-132/miR-212, and that REST is a critical determinant of stress resistance and cognitive preservation during aging.Medical Sciences
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Platt, Thomas. "LEPTIN RESISTANCE INDUCED OBESITY AND DIABETES PROMOTE NEUROPATHOLOGICAL CHANGES IN THE AGING BRAIN." UKnowledge, 2014. http://uknowledge.uky.edu/biochem_etds/18.
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The aging brain is prone to the development of pathology and dementia. With a rapidly growing elderly population diagnoses of neurodegenerative diseases, such as Alzheimer’s disease (AD), frontotemporal dementia (FTD), and Parkinson’s disease are on the rise. Additionally, diabetes and obesity are linked to an increased risk of dementia. The convergence of this increasingly aged population with the obesity and diabetes epidemic give rise to new concerns regarding the future of prevention and treatment of neurodegenerative diseases. Our lab has previously shown that leptin, an adipokine involved in signaling satiety to the hypothalamus, can modulate the generation of the amyloid beta (Aβ) peptide (a toxic peptide associated with neurologic disease) and attenuate hyperphosphorylation of the tau protein (another peptide prone to forming large insoluble structures causing neurodegeneration). From these studies we have elucidated that leptin resistant mice (which develop severe obesity and type-2 diabetes mellitus) with knock-in mutations for the amyloid precursor protein (APP) and presenilin-1 (PS1) genes develop extensive vascular pathology and cognitive impairments. Interestingly, these mice do not display increased levels of amyloid deposition in the brain. Additionally, increased tau phosphorylation occurs in these mice with leptin resistance. As a follow up to this study db mice were transduced, via adeno-associated virus, with the tau P301L mutant to induce the development of tangle pathology. These mice displayed no cognitive deficits, yet they displayed increases in both tau phosphorylation and tangle count within the hippocampus. Collectively, these studies indicate leptin resistance, obesity, and type-2 diabetes mellitus promote the development of cerebrovascular and neurofibrillary tangle pathologies associated with neurodegeneration and dementia. These observations open many previously unexplored avenues for developing novel therapeutics to treat these devastating diseases.
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Li, Zhuo. "Modulation of IGFBP2 upon aging, obesity and insulin resistance in mice and humans." Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/28371/28371.pdf.
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Flack, Kyle. "Effects of Resistance Training on aged Skeletal Muscle and Mitochondrial Function." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/25143.
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With the aging of the baby boom population and an increased life expectancy, individuals aged 65 years and older are the fastest growing segment of our population. Aging brings about changes in skeletal muscle such as reduced muscle strength and mass, as well as cellular deficits such as increased production of reactive oxygen species (ROS), and mitochondrial DNA (MtDNA) deletions and mutations. Muscle mass declines at a rate of 1-2% each year after the age of 50, leading to muscle weakness, functional impairments, loss of independence, and an increase in falls. Additional declines in muscle mass and reduced muscle strength may result in a lower resting metabolic rate, reduced lipid oxidative capacity, increased adiposity, and insulin resistance. The rising number of individuals aged 65+ will increase demands on health care and health care costs, possibly leading to inadequate public resources and less care for the aged. This large societal impact, coupled with the aging of our population, suggests a clear need for methods that will improve the aging phenotype to enhance functionality, quality of life, and overall health for our aging population. This investigation aspires to delve into a relatively unexplored area of aging research and evaluate potential means that could help improve the aging phenotype.
The associated mitochondrial impairments, mitochondrial mediated apoptosis, and mitochondrial DNA (MtDNA) deletions and mutations that accompany aging lead to a decline in physical fitness and oxidative capacity, and exercise has been shown to reverse or help prevent many of these disturbances. Resistance exercise training (RT) is currently the most effective known strategy to stimulate skeletal muscle hypertrophy and increase strength. Strength gains after RT lead to an improvement in activities of daily living and quality of life. There is some evidence suggesting that RT may lead to increased antioxidant enzyme capacity, decreased ROS production and increased electron transport chain (ETC) function in older individuals. The present study will lay a foundation for future research and further developments in the area of RT, mitochondrial function and aging.Ph. D.
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Kanemaru, Yoshinori. "Absence of GIP secretion alleviates age-related obesity and insulin resistance." Kyoto University, 2020. http://hdl.handle.net/2433/258993.
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William, DuPont. "The Effects of Resistance Exercise Training on Cognition and Brain Function in Healthy Older Adult Women." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1532087071781131.
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Schultz, Thomas. "ReRAM based platform for monitoring IC integrity and aging." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1573576246158436.
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Law, Ka-man, and 羅嘉敏. "Characterization of lipocalin-2, the pro-inflammatory adipokine, in the development of insulin resistance associated with aging and obesity." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hdl.handle.net/10722/192777.
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Yamada, Chizumi. "Genetic inactivation of GIP signaling reverses aging-associated insulin resistance through body composition changes." Kyoto University, 2008. http://hdl.handle.net/2433/135794.
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Dietrich, Olaf. "Understanding the ageing consumer : exploring strategies for overcoming innovation resistance." Thesis, University of Gloucestershire, 2016. http://eprints.glos.ac.uk/3838/.
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This thesis deals with the trend of an ageing population in Germany and the opportunities and challenges that it presents for the consumer goods industry. The goal of the research is to provide a more nuanced understanding of ageing consumers and to suggest strategies to overcome innovation resistance. It departs from the traditional product-oriented research perspective and explores domestic practices of everyday life. Using this approach, it investigates the role of household appliances in facilitating the wish of older adults to age-in-place. Due to the interdisciplinary nature of the research, a synthetic framework was created that melds and extends distinct conceptual elements from separate theories. While previous studies have largely failed to provide a detailed description of user segments, this research applies a novel market segmentation approach that assists in developing more effective innovation strategies. It has extended the Use Diffusion model (Shih & Venkatesh, 2004) by creating a number of novel sub-determinants which direct household technology use in different directions. It posits that different user segments exhibit different levels of interest in future technology acquisition. Based on an advanced understanding of use patterns, the research intends to clarify a possible application of disruptive innovations, which suggest simpler, more familiar and affordable products and services. The research followed a sequential approach to data generation. It begins with interviews conducted during home visits using the task of ‘doing the laundry’ as a focal practice, interviews with care workers, and medical practitioners. It is supplemented with focus groups comprised of the intended product users in order to generate innovation ideas. A final focus group of industry experts followed and centred on the operationalization of those ideas within an established company. Finally, the thesis developed a synthetic model to support innovation management that is not present in current conceptions.
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O'Neill, Elaine. "The effect of insulin resistance on ageing of skeletal muscle." Thesis, University of Liverpool, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.539510.
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Williamson, Kirstin. "Evolutionary trade-offs with innate immune resistance : implications for ageing, oxidative stress resistance and motor function." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/363662/.
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Resistance to infection is essential to ensure survival and thus maximise offspring potential. However, resistance is not ubiquitous across the animal kingdom, or even within a population from the same species. It is thought that this is due, in part, to the costs involved in producing and maintaining a competent immune system and a corresponding decrease in other fitness-related characteristics. The focus of this research was to determine how immune resistance can impact upon mechanisms relating to ageing, resistance to oxidative stress and motor function. In order to do this a Drosophila melanogaster model system was implemented, selected for resistance to larval parasitism by the parasitoid wasp, Asobara tabida. Firstly, it was necessary to gain a greater understanding of the immune mechanisms within the Drosophila model. This included how aspects of the immune system changed over time, in order to determine how these might act upon other processes at different stages of the ageing system. Resistance to larval parasitism corresponded to an increased number of circulating immune cells during the larval phase. This difference was no longer apparent in the adult Drosophila. Young resistant adult females revealed increased levels of overall cell metabolism, measured by the production of intracellular reactive oxygen species (ROS), a finding not seen in males or in the developing larvae. Lifespan was reduced in the resistant female, but not male, Drosophila. It was hypothesised that this reduction may in part be due to the augmented production of intracellular ROS in the young adult female, which at high concentrations can cause oxidative stress with known cytotoxic effects. However, differences in resistance did not translate to altered survival under acute oxidative stress, induced by the consumption of the toxin paraquat. Other factors may regulate these changes in longevity in the resistant females, such as genetic or resource-based trade-offs. Functional assays were performed to assess motor function in the larvae and adult Drosophila. Resistant larvae showed less turning behaviour on a non-food background than their control counterparts, a trait generally linked to more proficient motor function. Differences in motor function continued into the adult females, where increased climbing velocities were found irrespective of age. This implies that changes in motor function may be determined during development, thus variations in resistance during this phase can cause life-long impacts on the individual, presumably by altering the development of other physiological systems.
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Martins, Luiz Claudio 1964. "Estudo comparativo das alterçaões cardiovasculares na hipertensão arterial resistente controlada e não controlada." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/309567.
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Orientador: Heitor Moreno JuniorTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas
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Resumo: Introdução Hipertensão resistente é definida como a pressão arterial que permanece acima da meta pressórica, apesar do uso de 3 classes de antihipertensivos sendo um deles um diurético. Recentes diretrizes da American Heart Association (AHA-2008) consideraram também hipertensos resistentes os pacientes que usam 4 ou mais classes e possuem suas pressões controladas. No entanto, é desconhecido se as repercussões cardíacas e vasculares nos pacientes hipertensos resistentes não controlados (HARNC) e controlados (HARC) são semelhantes e qual a influência do envelhecimento sobre esses subgrupos de hipertensos resistentes (HAR). Objetivo Comparar as repercussões cardíacas e vasculares nos HARNC e HARC e avaliar a influência do envelhecimento nesses subgrupos. Métodos Após a triagem e adesão rigorosa, noventa pacientes foram separados em HARNC (n=47) e HARC (n=43). Pressão arterial sistólica (PAS), pressão arterial diastólica (PAD), pressão de pulso (PP), velocidade de onda de pulso (VOP), índice de massa do ventrículo esquerdo (IMVE), índice de massa corpórea (IMC), concentração plasmática de aldosterona (CPA) e atividade renina plasmática (ARP) foram avaliados. Realizaram-se testes estatísticos paramétricos e não paramétricos e regressão linear multivariada (RLM) e univariada (RLU). Resultados A PAS, PAD, PP, VOP, IMVE, IMC e CPA foram maiores nos HARNC (PAS=170/150/204 mmHg; PAD=100/88/130 mmHg; PP=69/40/91 mmHg; VOP=10.9/8/15.3 m/s; IMVE=179±49.2 g/m2; IMC=32±2.1 Kg/m2 e CPA=24.4±3.2 ng/dL), comparados com os HARC (PAS=143/130/163 mmHg; PAD=90/70/116 mmHg; PP=54.5/30/75 mmHg; VOP=9.5/6.8/11.3 m/s; IMVE=140.3±30.1 g/m2; IMC=28.3±1.5 Kg/m2 e CPA=19.7±2.6 ng/dL)(p<0.001). A ARP foi maior nos HARC (ARP=4.3±1.2 ng/mL/h) comparado com os HARNC (ARP=1.08±0.32 ng/mL/h)(p<0.001). A RLM mostrou que a VOP foi significativamente dependente da idade em ambos os grupos, porém a influência do envelhecimento foi mais importante nos HARNC. A RLU mostrou que a CPA se correlaciona com a VOP somente nos HAR com mais de 60 anos. Conclusões Duas características estruturais cardiovasculares não foram semelhantes nos dois grupos estudados: a hipertrofia do ventrículo esquerdo e a rigidez arterial foram maiores nos HARNC. A influência do envelhecimento foi mais significativa neste último grupo. Além disso, a CPA e o IMC foram também maiores nos HARNC. Em seu conjunto, estes dados destacam a importância da aldosterona, envelhecimento e obesidade na patogênese da hipertensão arterial resistente controlada e não controlada.
Abstract: Introduction Resistant hypertension (RH) is defined as blood pressure that remains above goal in spite of the concurrent use of three antihypertensive agents of different classes. Ideally, one of the three agents should be a diuretic and all agents should be prescribed at optimal dose amounts. Recent American Heart Association guidelines include patients who are well controlled but are also considered as having resistant hypertension if they require four or more medications. However, we do not know if both "uncontrolled" (UCRH) and "controlled" CRH) resistant hypertension patients have a similar impact on the cardiac and vascular structure and function, and how the aging influence these groups. Methods After confirming compliance to treatment, 90 patients were divided in two subgroups: UCRH (n=47) and CRH (n= 43) patients. Office blood pressure (BP), pulse wave velocity (PWV), left ventricular mass index (LVMI), body mass index (BMI), plasma aldosterone concentration (PAC) and plasma renin activity (PRA) were evaluated. Parametric and nonparametric statistical tests and multivariate and univariated linear regression analysis were performed. Objective The aim of this study was to identify patient characteristics that distinguish individuals with CRH from individuals with UCRH, We especially wanted to compare the effects of aging, RAAS activation, and vascular stiffness on lack of BP control. Results Office systolic blood pressure (SBP), diastolic blood pressure (DBP), Pulse Pressure (PP), PWV, LVMI, PAC and PRA were higher in UCRH (SBP=170/150/204mmHg; DBP=100/88/130mmHg; PP=69/40/91mmHg, PWV=10.9/8/15.3m/s; LVMI=179±49.2g/m2; BMI=32±2.1Kg/m2; PAC=24.4±3.2ng/dL) than in CRH group (SBP=143/130/163mmHg; DBP=90/70/116mmHg; PWV=9.5/6.8/11.3 m/s; LVMI=140.3±30.1g/m2; BMI=28.3±1.5Kg/m2 and PAC=19.7±2.6 ng/dL) (p<0.001). PRA was higher in CRH (PRA=4.3±1.2ng/mL/h) than in UCRH (PRA=1.08±0.32ng/mL/h)(p<0.001). Multivariate linear regression analysis of variables in function of age indicated that the PWV was significantly dependent of age in both UCRH and CRH patients; moreover, the influence of aging was more important in the former group. Univariate linear regression analysis showed that PAC correlates with PWV only in RH subjects over than 60 years old. Conclusions Clearly, at least two cardiovascular structural characteristics were not similar in the two studied groups: LV hypertrophy and arterial stiffness were more prominent in UCRH individuals and the influence of aging was more important in this group. Also, PAC and BMI were higher elevated in the UCRH group; taken together these results reinforce the concept that links obesity and RH through the hyperaldosteronism, and the important role of aldosterone in the pathogenesis of the metabolic syndrome and controlled and uncontrolled resistant hypertension.
Doutorado
Doutor em Farmacologia
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SETHI, VARUN. "Effect of Aging on Abrasive Wear Resistance of Silicon Carbide Particulate Reinforced Aluminum Matrix Composite." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1191951786.
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Ramsey, Michael W., Bradley J. Behnke, Rhonda D. Prisby, and Michael D. Delp. "Effects of Aging on Adipose Resistance Artery Vasoconstriction: Possible Implications for Orthostatic Blood Pressure Regulation." Digital Commons @ East Tennessee State University, 2007. https://dc.etsu.edu/etsu-works/4135.
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The purpose of this investigation was to determine mean arterial pressure (MAP) and regional vascular conductance responses in young and aged Fisher-344 rats during orthostatic stress, i.e., 70° head-up tilt (HUT). Both groups demonstrated directionally different changes in MAP during HUT (young, 7% increase; aged, 7% decrease). Vascular conductance during HUT in young rats decreased in most tissues but largely remained unchanged in the aged animals. Based on the higher vascular conductance of white adipose tissue from aged rats during HUT, resistance arteries from white visceral fat were isolated and studied in vitro. There was diminished maximal vasoconstriction to phenylephrine and norepinephrine (NE: young, 42 ± 5%; old, 18 ± 6%) in adipose resistance arteries from aged rats. These results demonstrate that aging reduces the ability to maintain MAP during orthostatic stress, and this is associated with a diminished vasoconstriction of adipose resistance arteries.
With advancing age the ability to tolerate orthostatic stress (17, 22) and perform exercise (11, 15, 34) is reduced. One possible mechanism for these age-related changes is a diminished arterial vasoconstrictor responsiveness, which could impair redistribution of cardiac output during exercise and limit reductions in vascular conductance during orthostasis. The ability to diminish vascular conductance in nonactive tissue is requisite during orthostasis to maintain mean arterial pressure (MAP) and sustain adequate brain perfusion. However, whether regional vascular conductance during orthostasis is altered by aging remains unknown.
Head-up tilt (HUT) has been utilized extensively to study cardiovascular system responsiveness to orthostatic stress in humans and animals (8, 13, 14, 16, 26, 31). Postural changes from the supine position to the upright posture elicit a blood volume shift from the thoracic cavity to the lower limbs (29), which results in reduced venous return and, subsequently, decreased stroke volume. The resultant decrease in cardiac output must be offset by a decrease in peripheral vascular conductance (PVC) to maintain arterial blood pressure (29). Since there is a greater incidence of orthostatic hypotension with advancing age (16, 25, 31, 38), the primary purpose of the present study was to determine whether a diminished ability to maintain MAP during an orthostatic stress is manifest in aged Fischer-344 rats and to identify whether alterations in regional vascular conductance correspond to a putative orthostatic hypotension. Specifically, we hypothesized that with HUT, aged animals will demonstrate a diminished vasoconstriction in some tissues, as evidenced by higher blood flows and vascular conductance relative to that in young adult rats. The results indicated an inability of old rats to diminish vascular conductance in several tissues, including white adipose tissue, during HUT. Therefore, a secondary purpose was to test the hypothesis that aging diminishes myogenic and adrenergic vasoconstriction of resistance vessels from white visceral adipose tissue. The results from this series of experiments may indicate an underlying mechanism for the old age-related orthostatic intolerance. Given that adipose tissue makes up a greater proportion of body composition with aging in rats (7) and humans (1), a reduced vasoconstriction of resistance vessels from this tissue could have significant ramifications on the ability to decrease peripheral vascular conductance during orthostatic challenges and with exercise among the elderly.
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Behnke, Bradley J., Michael W. Ramsey, John N. Stabley, James M. Dominguez, Robert T. Davis, Danielle J. McCullough, Judy M. Muller-Delp, and Michael D. Delp. "Effects of Aging and Exercise Training on Skeletal Muscle Blood Flow and Resistance Artery Morphology." Digital Commons @ East Tennessee State University, 2012. https://dc.etsu.edu/etsu-works/4125.
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With old age, blood flow to the high-oxidative red skeletal muscle is reduced and blood flow to the low-oxidative white muscle is elevated during exercise. Changes in the number of feed arteries perforating the muscle are thought to contribute to this altered hyperemic response during exercise. We tested the hypothesis that exercise training would ameliorate age-related differences in blood flow during exercise and feed artery structure in skeletal muscle. Young (6–7 mo old, n = 36) and old (24 mo old, n = 25) male Fischer 344 rats were divided into young sedentary (Sed), old Sed, young exercise-trained (ET), and old ET groups, where training consisted of 10–12 wk of treadmill exercise. In Sed and ET rats, blood flow to the red and white portions of the gastrocnemius muscle (GastRed and GastWhite) and the number and luminal cross-sectional area (CSA) of all feed arteries perforating the muscle were measured at rest and during exercise. In the old ET group, blood flow was greater to GastRed (264 ± 13 and 195 ± 9 ml·min−1·100 g−1 in old ET and old Sed, respectively) and lower to GastWhite (78 ± 5 and 120 ± 6 ml·min−1·100 g−1 in old ET and old Sed, respectively) than in the old Sed group. There was no difference in the number of feed arteries between the old ET and old Sed group, although the CSA of feed arteries from old ET rats was larger. In young ET rats, there was an increase in the number of feed arteries perforating the muscle. Exercise training mitigated old age-associated differences in blood flow during exercise within gastrocnemius muscle. However, training-induced adaptations in resistance artery morphology differed between young (increase in feed artery number) and old (increase in artery CSA) animals. The altered blood flow pattern induced by exercise training with old age would improve the local matching of O2 delivery to consumption within the skeletal muscle.
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Bet, Da Rosa Orssatto Lucas. "Effects of ageing and resistance training on intrinsic motor neurone excitability." Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/233612/1/Lucas_Bet%20Da%20Rosa%20Orssatto_Thesis.pdf.
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This thesis examined the age-related impairments in the function of motor neurones, the connection between our spinal cord and the muscles, and the use of exercise as a therapy to counteract this dysfunction. Older adults have reduced function of the motor neurones, which could contribute to muscle weakness and physical function impairments observed in this population. Exercise can be used as medicine to restore motor neurone function, contributing to improvements in muscular strength and general physical function in older adults.
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Brown, Robert G. "The effect of progressive resistance strength training exercise on serum growth hormone and testosterone in young and elderly men." Virtual Press, 1987. http://liblink.bsu.edu/uhtbin/catkey/494560.
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The purpose of this study was to observe the response of serum hormones to a progressive resistance strength training program. Basal levels of serum growth hormone and total testosterone were measured before and after a 12-week strength training program in 8 young men (mean age= 23 years) and 13 elderly men (mean age= 63 years). The response of growth hormone and testosterone to an acute bout of strength training exercise was also measured. Changes in lean body mass, percent fat, fat weight, VO2max and girth measurements were determined.Sessions were started with walking and static stretching exercises for the major muscle groups. This was followed by 45-60 minutes of isotonic strength training exercise which consisted of the leg-press, leg-extension, leg-curl, torso extension, bench-press, pull-down, pull-over, horizontal arm adduction, arm adduction, and modified sit-ups on an abdominal platform. Subjects were told to increase weight at a station when they could successfully complete three sets of ten repetitions at that station. At weeks 2 and 12 of the study subjects were strength tested at the leg-press, leg-extension, and bench-press stations. Strength was measured as the most weight that could be lifted for six repetitions. Blood samples were drawn from an antecubital vein pre and post training, and before, immediately following and 15 minutes after an exercise session.There was a significant increase (p <0.001) in strength for both groups for the leg press, leg extention and bench press. However, the young group was significantly stronger (p <0.001) than the elderly group in both pre and post test for all muscles measured. There was a significant increase (p <0.01) in lean weight in the elderly group which was correlated with increased strength on the leg press, leg extension and bench press on the post test. There was a significant increase (p <0.05) in growth hormone for both groups in response to an acute bout of exercise on both the pre and post test with the rise being significantly higher (p <0.025) in the young group. The increased strength in the young group correlated positively with increased serum growth hormone following an acute bout of exercise on the post test. There was no significant change in serum testosterone in response to an acute bout of exercise in either group. Basal levels of growth hormone and testosterone did not change.
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Somogye, Ryan H. "An aging model of Ni-MH batteries for use in hybrid-electric vehicles." Connect to resource, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1134658219.
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Thesis (M.S.)--Ohio State University, 2004.Advisor: Stephen Yurkovich, Dept. of Electrical Engineering. Includes bibliographical references (leaves 155-156). Available online via OhioLINK's ETD Center
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Kastello, Gary M. "The effects of aging, exercise and food restriction on the development of insulin resistance in adipocytes of young rats." Virtual Press, 1987. http://liblink.bsu.edu/uhtbin/catkey/495214.
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Male Sprague-Dawley rats were used to determine whether insulin resistance develops between 1.5-4.0 months of age and whether it is related to aging or the development of obesity. Animals were randomly placed into a single 1.5 months old group (1.5 CN) or raised in one of three 4.0 month old groups; exercise trained (ET), pairfed (PF), or sedentary control (4.0 CN). The ET group was fed ad Iibitum and had free access to a spontaneous exercise wheel, while the PF group was fed to maintain equal body weight with the ET group. The young group was sacrificed with nembutal injection (45 mg/kg body weight) at 1.5 months while the other three groups were sacrificed at 4.0 months of age. Epididymal fat pads were removed, digested with collagenase (5 mg/ml) and the isolated cells sized and assayed for 2-deoxyglucose transport over a range of insulin concentrations (0-1000 µU/ml). Body composition (percent fat, bone and muscle) was performed on the carcasses of these animals at a later date. The 2-deoxyglucose transport of the 1.5 CN group was significantly greater than the 4.0 CN group at insulin concentrations of 50, 250 and 1000 uU/ml and significantly greater than all 4.0 months groups at 1000 11U/ml- The adipocyte size was significantly smaller in the 1.5 CN group followed in ascending order by the ET, PF and 4.0 CN group. The body compositions demonstrated the expected trends as the 1.5 CN group had the highest percent bone and muscle while demonstrating the lowest percent fat. The ET group was most able to maintain the body composition of the 1.5 CN group, while the PF and 4.0 CN groups were least able to maintain this composition respectively.The results indicate that: 1) Adipocyte insulin resistance develops in the rat between 1.5 and 4.0 months of age. 2) This development of insulin resistance is related to obesity and not to aging. 3) Exercise may prevent the development of insulin resistance by preventing adipocyte hypertrophy. 4) Exercise helps maintain optimal body composition. These results should be of interest to type II diabetics as an exercise program may decrease their adipocyte size, enhance body composition and decrease insulin resistance.
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Jambassi, Filho José Claudio [UNESP]. "O efeito de diferentes intervalos de recuperação entre as séries do treinamento com pesos, nas respostas neuromusculares e do hormônio do crescimento, em idosas treinadas." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/87381.
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Esta dissertação explorou por meio de dois estudos o efeito de diferentes intervalos de recuperação (IR) entre as séries do treinamento com pesos (TP) nas respostas: 1) neuromusculares agudas [número de repetições (NR) por séries, sustentabilidade das repetições entre as séries, volume total, contração voluntária máxima (CVM) e atividade eletromiográfica (atividade EMG)] e crônicas [da CVM, taxa de desenvolvimento de força pico (TDFP) e cargas absolutas de 15 repetições máximas (15 RM)]; 2) agudas das concentrações do hormônio do crescimento (GH). O primeiro estudo foi concluído com 21 participantes (66,4 +- 4,4 anos) e o segundo com 19 participantes (66,1+- 4,3 anos). Inicialmente todas as participantes realizaram duas sessões de familiarização aos procedimentos de avaliação da curva força-tempo isométrica (Cf-t isométrica) e três sessões para determinação das cargas referentes a 15 RM no exercício leg-press. Nas três visitas subseqüentes, foram realizadas duas sessões de teste adotando-se IR entre as séries de um (IR-1) e três (IR-3) minutos e uma sessão controle. Nas sessões de teste, as participantes realizaram três séries até a fadiga muscular com a carga de 15 RM e avaliações da curva força-tempo isométrica (Cf-t isométrica) e da atividade EMG pré e cinco minutos pós-sessões de teste. Na sessão controle, as participantes realizaram as mensurações da Cf-t isométrica e da atividade EMG pré e após permanecerem em repouso por 15 minutos. Após as coletas iniciais, as participantes foram separadas aleatoriamente em dois grupos: um treinou com IR de um minuto (G-1 min) entre todas as séries e o outro com três minutos (G-3 min). Ambos os grupos realizaram oito semanas de TP com as seguintes características: a) três sessões semanais; b) oito exercícios; c) intensidade relativa...
This dissertation explored through two studies the effect of different rest intervals (RI) between sets of resistance training (RT) in the responses: 1) acute neuromuscular [number of repetitions (NR) in sets, sustainability of repetitions between sets, total volume, maximal voluntary contraction (MVC) and electromyography activity (EMG activity)] and chronic [MVC, rate of force development peak (RFDP) and absolute loads of 15 repetitions maximum (15 RM)]; 2) acute concentrations of growth hormone (GH). The first study was completed with 21 participants (66.4 +- 4.4 years) and the second with 19 participants (66.1 +- 4.3 years). Initially, all participants performed two familiarization sessions to procedures of the isometric force-time curve (Cf-t isométrica) and three sessions to determine the load corresponding to 15 RM in the exercise leg-press. In three subsequent visits, there were performed two test sessions adopting IR between sets of one (RI-1) and three (RI-3) minutes and one control session. In test sessions, the participants performed three sets to muscular fatigue with the load of 15 RM and evaluations of Cf-t isometric and EMG activity pre and five minutes post-test session. In the control session, the participants performed measurements of Cf-t isometric and EMG activity before and after remaining at rest for 15 minutes. After the initial collection, participants were divided randomly into two groups: one trained with one minute (G-1 min) between all sets and the other with three minutes (G-3 min). Both groups performed eight weeks of RT with the following characteristics: a) three times a week b) eight exercises; c) relative intensity adjusted so that muscular fatigue occurred in 15 RM in the last set. At the end of eight weeks of RT, the participants were retest again... (Complete abstract click electronic access below)
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Alipour, A. "Characterization of Elastomer Nanocomposite Blends Based on NR/EPDM/Organoclay." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35610.
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Elastomer nanocomposites based on NR/EPDM/organoclay were prepared by two-roll mill to investi-gate the effect of different percentages of nanoclay (0, 1, 3, 5 & 7 Wt%) and different matrix compositions (100/0, 75/25, 50/50, 25/75 & 0/100) on the microstructure, mechanical properties and best applicability of the mathematical models. Results of X-ray diffraction showed that enlargement of the silicate layers, pene-tration of polymer chains into layers and formation of an intercalated and exfoliated structure which was confirmed by TEM analysis. Mechanical properties as well as heat build up of the samples improved by addition of nanoclay. Addition the compounds with EPDM leads to an increase in compression strength, modulus and compressin set and decrease in tensile and tear strength. The prepared samples receive more aging resistance by addition of more clay and EPDM.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35610
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Lockyer, Scott Andrew. "The strength and fatigue resistance of a precipitate strengthened Cu-Ni-Si alloy." Thesis, University of Liverpool, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240271.
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Suttman, Alexander K. "Lithium Ion Battery Aging Experiments and Algorithm Development for Life Estimation." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1306937891.
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Hausman, Natasha L. "The influence of caveolin-1 and ageing on resistance artery structure and function." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.514440.
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Ageing is a risk factor for cardiovascular disease (CVD) and involves changes in the function and structure of resistance arteries. Membrane invaginations called caveolae are involved in cell signalling regulation, and can influence the active and passive properties of resistance arteries. Changes in caveolae and their structural protein caveolin-l have been implicated in CVD, therefore the role of caveolin-l in vascular ageing was investigated. Isolated resistance arteries from 3 and 12 month old wild-type (WT) and caveolin-l knock-out (KO) mice were examined. Mesenteric and femoral arteries mounted on a pressure myograph were exposed to a high potassium solution (KPSS), noradrenaline (NA), acetylcholine (ACh) and sodium nitroprusside. Concentration-response curves to NA and ACh were also performed in the presence of the nitric oxide synthase inhibitor NG-nitro-L-arginine. Pressure steps in calcium-free solution allowed investigation of passive vessel properties. Mesenteric arteries from 12 month old WT mice exhibited reduced constriction to NA and KPSS, increased nitric oxide (NO) availability and outward hypertrophic remodelling when compared to those from 3 month old WT mice. Similar changes were observed in arteries from 3 month old caveolin- 1 KO mice compared to age-matched WT controls. There was no age-related change in the response of vessels from caveolin-l KO mice to NA, and no significant role for NO in mesenteric arteries from 12 month old caveolin-l KO mice. However, femoral arteries from 12 month old caveolin-l KO mice dilated more to ACh than WT controls, in line with increased NO availability. This would be .consistent with increased endothelial nitric oxide synthase (eNOS) activity in the absence of inhibition by caveolin-l. Increased NO production in femoral arteries from caveolin-l KO mice was also associated with reduced distensibility, which may act to maintain blood pressure. Vessels from 3 month old female WT mice constricted less to NA than vessels from age-matched male mice. Caveolin-l ablation abolished this gender difference. The effects of caveolin-l ablation on vessels from 3 month old male mice were in line with the effects of ageing in male WT mice, suggesting premature vascular ageing in young male caveolin-l KO mice. Ageing in female WT mice and caveolin-l ablation in 3 month old female mice did not have the same effects, suggesting oestrogens may modify vascular ageing. Gender differences in the effects of ageing on vessels from caveolin-l KO mice were also observed. There was no age-related decrease in NO availability in vessels from female mice, in contrast to males. Vessels from female caveolin-l KO mice underwent age-related outward hypertrophic remodelling, in contrast to atrophy of vessels in male mice. This may reflect the role of oestrogens in regulating vascular function and structure. Caveolae appear to be involved in mediating the effects of vascular ageing and gender differences in vascular responses. Interactions between oestrogens, eNOS and caveolae may therefore be important in long-term regulation of vascular function and structure. As vascular ageing may contribute to development of CVD, and there are gender differences in the incidence of CVD, the role of caveolae may be an important consideration in the design of future therapeutic treatments.
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Groshong, Jason S. "THE ROLE OF MACROPHAGES IN EXERCISE AND INSULIN RESISTANCE IN HUMAN SKELETAL MUSCLE." UKnowledge, 2013. http://uknowledge.uky.edu/physiology_etds/13.
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Muscle biopsies were taken at baseline, post eccentric exercise, post aerobic training, and after training followed by eccentric exercise from adults with different health status. In Cell Western analysis of pAkt/Akt ratio suggests that muscle cells isolated from baseline biopsies respond to insulin in a dose dependent manner that tracks with sensitivity to insulin of the host; however, this is uncoupled from glucose disposal in vitro. Nitrotyrosine (NY), a marker of free radical damage, was employed to assess the efficacy of the exercise paradigm. NY immunohistochemistry on muscle cross-sections revealed that eccentric exercise significantly increased damage in older (>55 years of age), but not middle aged (age) subjects, and that training reversed the post eccentric damage significantly in the younger, but not the older group, suggesting distinct adaptation to eccentric exercise. Assessment of total macrophage content by CD68 immunohistochemistry showed that macrophage abundance increased in response to training in the >55 years age group, but not in the training, macrophages increased in response to eccentric exercise in middle aged and decreased in older subjects, showing a disconnect from NY damage. Macrophage phenotypes were assessed in these groups via the M1 marker CD11b, and the M2 marker, CD206. Two dominant populations of macrophages were identified, one of which co-expressed CD11b and CD206, and another which only expressed CD11b. These two populations of macrophages showed the same trends in expression in response to exercise observed with CD68, but did not achieve statistical significance. Bivariate analysis revealed that CD11b/CD206 macrophage densities were correlated with gene activities associated with fibrosis and angiogenesis, whereas CD11b macrophages correlated with gene activities associated with proteostasis and cellular turnover. Lastly, an in vitro model of skeletal muscle cell and macrophage integration was developed to study how macrophage phenotype influences insulin responsiveness. Data suggest that M1 macrophages inhibit insulin stimulated glucose disposal, whereas M2 macrophages enhance this response. Taken together these results suggest a functional distinction between inflammatory (M1) and alternative macrophages (M2) in exercise and insulin resistance that is altered with age.
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Martin, Richard Joseph. "Planning for Decisional Incapacity: Resistance to Cognitive Bias in Older Adults." Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case1562347931852291.
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Jambassi, Filho José Claudio. "O efeito de diferentes intervalos de recuperação entre as séries do treinamento com pesos, nas respostas neuromusculares e do hormônio do crescimento, em idosas treinadas /." Rio Claro : [s.n.], 2011. http://hdl.handle.net/11449/87381.
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Orientador: Sebastião GobbiBanca: Mara Patricia T. Chacon Mikahil
Banca: Vilmar Baldissera
Resumo: Esta dissertação explorou por meio de dois estudos o efeito de diferentes intervalos de recuperação (IR) entre as séries do treinamento com pesos (TP) nas respostas: 1) neuromusculares agudas [número de repetições (NR) por séries, sustentabilidade das repetições entre as séries, volume total, contração voluntária máxima (CVM) e atividade eletromiográfica (atividade EMG)] e crônicas [da CVM, taxa de desenvolvimento de força pico (TDFP) e cargas absolutas de 15 repetições máximas (15 RM)]; 2) agudas das concentrações do hormônio do crescimento (GH). O primeiro estudo foi concluído com 21 participantes (66,4 +- 4,4 anos) e o segundo com 19 participantes (66,1+- 4,3 anos). Inicialmente todas as participantes realizaram duas sessões de familiarização aos procedimentos de avaliação da curva força-tempo isométrica (Cf-t isométrica) e três sessões para determinação das cargas referentes a 15 RM no exercício leg-press. Nas três visitas subseqüentes, foram realizadas duas sessões de teste adotando-se IR entre as séries de um (IR-1) e três (IR-3) minutos e uma sessão controle. Nas sessões de teste, as participantes realizaram três séries até a fadiga muscular com a carga de 15 RM e avaliações da curva força-tempo isométrica (Cf-t isométrica) e da atividade EMG pré e cinco minutos pós-sessões de teste. Na sessão controle, as participantes realizaram as mensurações da Cf-t isométrica e da atividade EMG pré e após permanecerem em repouso por 15 minutos. Após as coletas iniciais, as participantes foram separadas aleatoriamente em dois grupos: um treinou com IR de um minuto (G-1 min) entre todas as séries e o outro com três minutos (G-3 min). Ambos os grupos realizaram oito semanas de TP com as seguintes características: a) três sessões semanais; b) oito exercícios; c) intensidade relativa... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: This dissertation explored through two studies the effect of different rest intervals (RI) between sets of resistance training (RT) in the responses: 1) acute neuromuscular [number of repetitions (NR) in sets, sustainability of repetitions between sets, total volume, maximal voluntary contraction (MVC) and electromyography activity (EMG activity)] and chronic [MVC, rate of force development peak (RFDP) and absolute loads of 15 repetitions maximum (15 RM)]; 2) acute concentrations of growth hormone (GH). The first study was completed with 21 participants (66.4 +- 4.4 years) and the second with 19 participants (66.1 +- 4.3 years). Initially, all participants performed two familiarization sessions to procedures of the isometric force-time curve (Cf-t isométrica) and three sessions to determine the load corresponding to 15 RM in the exercise leg-press. In three subsequent visits, there were performed two test sessions adopting IR between sets of one (RI-1) and three (RI-3) minutes and one control session. In test sessions, the participants performed three sets to muscular fatigue with the load of 15 RM and evaluations of Cf-t isometric and EMG activity pre and five minutes post-test session. In the control session, the participants performed measurements of Cf-t isometric and EMG activity before and after remaining at rest for 15 minutes. After the initial collection, participants were divided randomly into two groups: one trained with one minute (G-1 min) between all sets and the other with three minutes (G-3 min). Both groups performed eight weeks of RT with the following characteristics: a) three times a week b) eight exercises; c) relative intensity adjusted so that muscular fatigue occurred in 15 RM in the last set. At the end of eight weeks of RT, the participants were retest again... (Complete abstract click electronic access below)
Mestre
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Ahmad, Syed Sajid. "Characterizing the Aging-Driven Degradation Rate of Electrical Contact Resistance and Mechanical Integrity of Plastic-Encapsulated Au/Al Wire Bonds." Diss., North Dakota State University, 2015. http://hdl.handle.net/10365/24926.
Full textAbstract:
Gold-aluminum interconnect is an integral part of conventional chip packaging. The gold-aluminum interface deteriorates during the operation of a device due to the formation of gold-aluminum intermetallic compounds. Spatial changes during intermetallic formation cause voids, which separate the interface, resulting in the catastrophic failure of the bond, and hence the device. This phenomenon is driven by temperature and time. With increasing device densities and overall package miniaturization, device heat dissipation densities are increasing, necessitating adequate understanding of the phenomena to assure appropriate device life for the intended application. Intermetallic formation is governed by diffusion rules, but the observed failure rates reported in the literature many times diverge from Fickian pattern. This conflict is resolved in this dissertation. Various failure rates are considered to show that a digression from Fickian pattern is possible. An effort is undertaken to improve the understanding of failure modeling. Failure mechanism is analyzed and a solution is presented.
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Clifford, Angela. "Physical activity and cognition in the elderly." Thesis, Loughborough University, 2012. https://dspace.lboro.ac.uk/2134/12494.
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Dementia is a common cause of disability in the elderly and, in the absence of a successful long-term treatment, it is important to investigate possible lifestyle interventions to help reduce an individual s risk of developing the condition. This thesis investigated the relationship between physical activity and dementia risk, finding that not all research supports the link. The literature review presented in this thesis (Chapter 2) highlighted several possible mediating factors, specifically the type of physical activity performed, the cognitive domains being studied and participant characteristics. Women seemed most susceptible to the effect of physical activity and some other forms of midlife interventions, possible mechanisms for which were discussed in another review (Appendix A). The cognitive test battery to be used in later studies was evaluated for its relevance to dementia and treatment during a 6-month study of Alzheimer's disease patients and their carers (Chapter 3). Memory tasks were found to be especially sensitive to clinical outcomes of dementia treatment (Chapter 4). An observational study of Indonesian elderly found a positive relationship between physical activity and memory performance on the same tests. This effect was strongest in women and in those with no pre-existing cognitive impairment (Chapter 5). However, the relationship could be further modified by other demographic factors, such as education. Health was independently affected in this model by exercise and its association with engaging in physical activity in this cohort was further investigated in Chapter 6. A randomised controlled trial (Chapter 7) was conducted to assess the effect of a 12-week programme of non-aerobic physical activity in sedentary middle-aged adults. Results indicated that resistance training, but not flexibility exercises, influenced memory but not executive function. Overall, this thesis suggests that several types of physical activity may be effective at slowing cognitive decline in elderly groups who are at increased risk of dementia, such as those in middle age and elderly women (Chapter 8). These findings should be expanded with the aim to improve healthcare advice and influence policy-making.
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Tsaousidou, Eva [Verfasser], Jens Claus [Akademischer Betreuer] Brüning, and Sigrun [Akademischer Betreuer] Korsching. "Hypothalamic Inflammation in Obesity, Insulin Resistance and Ageing / Eva Tsaousidou. Gutachter: Jens Claus Brüning ; Sigrun Korsching." Köln : Universitäts- und Stadtbibliothek Köln, 2015. http://d-nb.info/1078997772/34.
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Phillips, Bethan E. "Resistance-exercise training : the effects on muscle function, body composition and risk factors for chronic disease with ageing." Thesis, University of Nottingham, 2012. http://eprints.nottingham.ac.uk/12796/.
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Mohamad, Mashani. "The Role of the Liver Sinusoidal Endothelial Cells in the Pathophysiology of Insulin Resistance." Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/15716.
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Ageing is associated with increased prevalence of metabolic syndrome, as well as impaired glucose metabolism, hyperinsulinemia and insulin resistance. The mechanism underlying these associations is poorly understood and is likely to be complex and multifactorial. The liver is the key target for insulin action and while the endothelium has been shown to influence insulin activity in muscle and fat, the role of the liver sinusoidal endothelium on the action of insulin in the liver is unknown. The liver sinusoidal endothelium is unique: it is perforated with transcellular pores called fenestrations that facilitate unimpeded passage of substrates between blood and hepatocytes. A constellation of age-related morphological changes in the liver sinusoidal endothelium known as pseudocapillarisation have been described in various species including rats, baboons and humans. During ageing, the liver sinusoidal endothelium thickens, there is basement membrane deposition, and the fenestrations are significantly reduced in size and number (defenestration). Age-related pesudocapillarisation has been shown previously to impede the transfer of lipoproteins and medications across the hepatic sinusoidal endothelium. This thesis tests the hypothesis that changes in the ageing liver contribute to age-related insulin resistance, with alterations of the liver sinusoidal endothelial cell leading to age-related impairment of insulin action and insulin resistance/glucose metabolism. This work aims to improve the understanding of the effects of ageing processes in the liver on insulin action and glucose metabolism. It investigates the role of age-related pseudocapillarisation and the acutely induced poloxamer 407 (P407) model of defenestration in hepatic disposition of insulin and glucose metabolism. This thesis also investigates the effect of P407 on the relationship between membrane rafts and fenestrations in SKHep1 cells, a cell line of liver endothelial origin and isolated LSECs. Finally, the effects of dietary macronutrients and calorie intake on fenestrations in old age are examined. The work contained in this thesis aims to examine the role of age-related pseudocapillarisation in one of the major causes of age-related disease and disability, insulin resistance. In doing so it explores the potential mechanisms involved in these changes and how we may alter the progression of ageing through nutritional intervention.
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Emerson, Nadia. "The Effects of 6-weeks of Resistance Training on the Neuromuscular Fatigue Threshold in Older Adults." Master's thesis, University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5631.
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Age-related deficits in muscle mass, strength, and function place an increased burden of work on existing skeletal muscle and may lead to early onset of neuromuscular fatigue (NMF) during activities of daily living. Resistance exercise (RE) is the proven method for improving neuromuscular function in healthy older adults. PURPOSE: To investigate the effects of 6 weeks of RE on the NMF threshold as well as strength and functional performance in older adults. METHODS: Twenty-four older adults were randomly assigned to 6 weeks of RE (EXE; n = 12; age 72 ± 6.3 y; BMI 28.4 kg/m2) or control (CONT; n = 12; age 70.3 ± 5.6 y; BMI 27.6 kg/m2). Body fat percent (BF%), lean mass (LM), and fat mass (FM) were measured using DEXA and participants performed a discontinuous cycle ergometer test, physical working capacity at fatigue threshold (PWCFT), to determine the onset of NMF. Functional performance was assessed by time to complete 5 chair rises (CHAIR) and walk an 8-foot course (WALK). Lower body strength was assessed by predicted 1-RM leg extension (1RM). Two-way Analysis of Variance (ANOVA; time [PRE, POST] x group [EXE and CONT]) and magnitude based inferences were used to compare dependent variables. RESULTS: RE significantly increased 1RM (35%; p = 0.001) and CHAIR (20%; p = 0.047). RE had a likely beneficial effect on WALK (15%) and a possibly beneficial effect on PWCFT (14%). There were no significant changes to LM or FM, however, women in EXE significantly decreased BF% (p = 0.020). CONCLUSION: Results suggest that RE improves measures of strength and functional performance and possibly the onset of NMF in older adults.M.S.
Masters
Child, Family, and Community Sciences
Education and Human Performance
Sport and Exercise Science; Applied Exercise Physiology
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Olofsson, Magnus. "Microbiological Surveillance in Primary Health Care : New Aspects of Antimicrobial Resistance and Molecular Epidemiology in an Ageing Population." Doctoral thesis, Linköpings universitet, Institutionen för medicin och hälsa, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-133246.
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Background The inexorable rise in antimicrobial resistance (AMR) interferes with the goals of health care services around the world, given how critical the antibacterials are in making infections treatable and surgical procedures doable. Nursing homes residents have been identified as a reservoir for AMR, possibly due to the combination of being physically and mentally frail, frequently treated with antibacterials, and frequently moved between nursing home and hospital. Microbiological surveillance is a key countermeasure against further AMR development. Yet, surveillance data is easily biased due to precision problems regarding how the data is collected and evaluated. Methods Beginning in 2008, we launched two programmes (“SHADES” and “MIDIO”) aimed to gathering AMR data in a systematic fashion from elderly nursing home residents and elderly people living in their own place of residence. In doing so, we focused on colonizing strains of the two most important nosocomial infectious agents, Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The bacteria were collected from multiple body sites and analysed with respect to antimicrobial susceptibility and genetic diversity. Results Active surveillance of AMR showed that (i) a S. aureus isolate could be retrieved from 1 in every 2 individuals given a single round of sampling, but aggregating several rounds of sampling, this figure might reach 7 in every 10 individuals, (ii) an E. coli isolate could be retrieved from 4 in every 5 individuals, (iii) the overall prevalence of AMR was favourable when compared to the situation in many other countries, (iv) the genetic diversity of S. aureus was generally high and provided only limited evidence of clonal expansion or contraction, and (v) diabetes mellitus was one of very few patient-level factors to show an association with the degree of genetic diversity in S. aureus. Conclusions The prevalence of colonization with S. aureus and E. coli was somewhat higher than expected, but the degree of AMR was very low. The genetic diversity of S. aureus was generally high. Diabetes mellitus emerged as the only patient-level factor associated with a higher degree of genetic diversity in S. aureus.
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Emiliani, Marco. "Development of measurement procedures for the evaluation of energy performances and ageing resistance of innovative cool coloured materials." Doctoral thesis, Università Politecnica delle Marche, 2014. http://hdl.handle.net/11566/242845.
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Il presente lavoro descrive lo sviluppo di procedure di misura per la valutazione delle
proprietà energetiche e di durabilità di rivestimenti cool colorati sviluppati nell’ambito del
progetto EU COOL-Coverings finanziato all’interno del FP7. I materiali cool sono
caratterizzati da un comportamento selettivo con elevata assorbanza nel visibile (colorati)
ed elevata riflettanza nel NIR (cool). L’attività è stata focalizzata su tre tipologie di materiali
per le coperture edili: piastrelle ceramiche e pitture per facciate e membrane bituminose per
tetti. In una prima fase sono state analizzate, mediante spettrofotometro, le proprietà
radiative dei nuovi prodotti. Quindi, per quantificarne l’impatto su edifici reali, è stato
definito un protocollo di prova nel quale rivestimenti standard e cool vengono applicati su
dimostratori in scala calibrati e diversi parametri termici continuamente monitorati nel
lungo termine. Infine, grazie ad un modello numerico validato sulla base dei dati
sperimentali, è stato stimato il risparmio energetico per diverse tipologie di edificio e condizioni climatiche. Uno dei principali limiti dei materiali cool è rappresentato
dall’invecchiamento naturale che causa una riduzione progressiva delle proprietà radiative
nel tempo. Per la determinazione della durabilità, gli attuali standard prevedono un periodo
di tre anni che tuttavia non è compatibile con il mondo dell’industria. Inoltre le attuali
procedure accelerate non sono applicabili in quanto non prendono in considerazione il
fenomeno del soiling che ha un impatto rilevante nella riduzione di riflettanza. È stato
quindi condotto uno studio sui meccanismi di invecchiamento naturale al fine di
identificarne le principali cause e di quantificarne l’effetto in termini di riflettanza. Infine, è
stato analizzato un metodo accelerato, recentemente proposto dal LBNL, la cui validità per
i nuovi prodotti è stata verificata confrontandone i risultati con quelli ottenuti in per
esposizione naturale.The objective of the present work is to define test procedures for the evaluation of energy and durability performances of innovative cool coloured products developed within COOL-Coverings project, co-funded by EU commission under FP7. These materials are spectrally selective (absorbing in the visible and reflecting in the NIR) thus combining aesthetics (colour) and cooling capabilities. Three products have been addressed: ceramic tiles and paints for façades and bituminous roof membranes. Radiative properties have been initially analysed with a spectrophotometer. To understand the impact of such technologies on buildings, a testing protocol has been defined in which cool and standard materials are applied to calibrated mock-ups and different thermal parameters are continuously monitored. Cooling energy savings have been finally estimated for different climates and applications using numerical building models validated by the experimental data collected in the demo campaign. Besides energy performances, an important issue for cool materials is represented by natural ageing that can determine a progressive reduction of radiative properties over the time. Current standards define a period of 3 years for the evaluation of ageing resistance. Such a duration is not compatible with industrial needs, while existing accelerated standards are not adequate, neglecting the soiling effect that has instead a large impact on cool performances. Part of the research was therefore dedicated to investigate ageing mechanisms identifying the main factors and quantifying the loss of reflectance on standard and cool materials. Finally, an accelerated ageing method recently proposed by the LBNL to simulate 3 year ageing in few days of lab test has been analysed. The applicability of this procedure, designed for roof and US climate, has been verified also for new products and Mediterranean climate demonstrating a correlation degree with natural testing higher than current predictive models.
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Hurst, Christopher. "Combined exercise training in older adults : application of a hydraulic resistance machine for multicomponent fitness improvement." Thesis, Teesside University, 2017. http://hdl.handle.net/10149/621728.
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Ageing is associated with declines in cardiorespiratory and muscular fitness; yet for older adults the ability to perform the basic tasks of daily living is partly dependent on upperand lower-body fitness. Exercise training is an effective approach to counteract these age associated declines, with combined exercise training and high-intensity interval training (HIT) capable of eliciting improvements in cardiorespiratory and muscular fitness simultaneously. Recently, a new hydraulic resistance exercise machine (Speedflex) has been developed with potential to be a viable training mode for older adults allowing users to perform high speed movements with upper- and lower-body muscles. Accordingly, the aim of this thesis was to evaluate the potential effectiveness of Speedflex as a training strategy in older adults. Initially, this work sought to determine the feasibility of performing exercise training using Speedflex in older adults by quantifying the acute training responses to 1) HIT and 2) strength training and comparing these against criterion exercise modes. Here, the observed physiological and perceptual responses demonstrated that Speedflex is a feasible mode of exercise training in older adults, capable of inducing a high-intensity training stimulus. Following this, a systematic review and meta-analysis was performed to quantify the effects of same-session combined exercise training in older adults with results demonstrating possibly small to possibly large beneficial effects on measures of fitness. As muscle power appears to be a critical determinant of physical functioning in older adults, chapter five evaluated the reliability of the Nottingham leg extensor power rig, finding it to be reliable both short- and long-term, thereby confirming its suitability as a primary outcome measure for the final study and providing data for sample size estimation. Finally, chapter six evaluated the effects of a 12-week combined upper- and lower-body HIT intervention using Speedflex on physical fitness in older adults. Clear beneficial improvements were observed for participants in the intervention group compared to those in the control group for maximal oxygen uptake (~8%), muscle power (~10%) and muscle strength (~6%). The findings presented in this thesis demonstrate that both same-session combined training and HIT performed using Speedflex are capable of simultaneously improving cardiorespiratory and muscular fitness in older adults.
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Cristea, Alexander. "Effects of Ageing and Physical Activity on Regulation of Muscle Contraction." Doctoral thesis, Uppsala University, Department of Neuroscience, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-9198.
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The aims of this study were to investigate the mechanisms underlying (1) the ageing-related motor handicap at the whole muscle, cellular, contractile protein and myonuclear levels; and (2) ageing-related differences in muscle adaptability.
In vivo muscles function was studied in the knee extensors. Decreases were observed in isokinetic and isometric torque outputs in old age in the sedentary men and women and elite master sprinters. A 20-week long specific sprint and resistance training successfully improved the maximal isometric force and rate of force development in a subgroup of master sprinters.
In vitro measurements were performed in muscle biopsies from the vastus lateralis muscle. Immunocytochemical and contractile measurements in single membrane permeabilized muscle fibres demonstrated ageing- and gender-related changes at the myofibrillar level. In sedentary subjects, data showed a preferential decrease in the size of muscle fibres expressing type IIa MyHC in men, lower force generating capacity in muscle fibres expressing the type I MyHC isoform in both men and women and lower maximum velocity of unloaded shortening (V0) in fibres expressing types I and IIa MyHC isoforms in both men and women. The master sprinters also experienced the typical ageing-related reduction in the size of fast-twitch fibres, a shift toward a slower MyHC isoform profile and a lower V0 of type I MyHC fibres, which played a role in the decline in explosive force production capacity. The fast-twitch fibre area increased after the resistance training period. A model combining single muscle fibre confocal microscopy with a novel algorithm for 3D imaging of myonuclei in single muscle fibre segments was introduced to study the spatial organisation of myonuclei and the size of individual myonuclear domains (MNDs). Significant changes in the MND size variability and myonuclear organization were observed in old age, irrespective gender and fibre type. Those changes may influence the local quantity of specific proteins per muscle fibre volume by decreased and/or local cooperativity of myonuclei in a gender and muscle fibre specific manner.
In conclusion, the ageing-related impairments in in vivo muscle function were related to significant changes in morphology, contractile protein expression and regulation at the muscle fibre level. It is suggested that the altered myonuclear organisation observed in old age impacts on muscle fibre protein synthesis and degradation with consequences for the ageing-related changes in skeletal muscle structure and function. However, the improved muscle function in response to a 20-week intense physical training regime in highly motivated physically active old subjects demonstrates that all ageing-related in muscle function are not immutable.
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Siaugues, Caroline. "Du « rencard » au « rancart » ? Une expérience psychique de passage : la retraite professionnelle de la femme." Thesis, Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCB176.
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L'expérience du passage à la retraite paraît susceptible d'induire le trouble sur la scène psychique de bien des femmes. Souvent l'objet d'une chère attente associé au mérite et à la délivrance, la retraite professionnelle marque aussi l'avancée en âge et ne peut donc être pensée sans les problématiques qu'engage la traversée du vieillissement. À l'appui de 28 entretiens de recherche réalisés auprès de femmes retraitées, âgées entre 60 et 66 ans, cette thèse se propose d'appréhender tant la complexité que la singularité du travail psychique réclamé par cette expérience de passage. Cette recherche montre que le traitement psychique de l'arrivée à la retraite est tributaire de l'organisation psychique. Par ailleurs, certains effets associés au statut hiérarchique occupé durant l'exercice professionnel permettent également d'approcher les modalités spécifiques de désinvestissement de l'« objet-travail » et de la « scène professionnelle ». Enfin, parce qu'il est susceptible de bouleverser tant les repères que les places investies par la femme, l'accès à la retraite semble pleinement re-convoquer certaines problématiques psychiques inhérentes au travail d'adolescence, offrant parfois l'occasion de l'approfondir. Cette thèse cherche à promouvoir une réflexion sur le travail de culture et la « mise en partage » de ses objetsExperiencing transition to retirement seems likely to induce disorder on many women's psychic scenes. As often happens, retiring from one's job is the focus of cherished expectations associated to merit and deliverance. Yet, it also portends getting on in years: it cannot therefore be envisaged without dealing with the problems incurred by coping with age. In support of 28 research interviews conducted with 60 to 66-year old retired women, this thesis aims to understand both the complexity and singularity of the psychic work required by such transitioning experience. This research shows that the mental processing of reaching retirement-age depends on the person's emotional organization. In addition, some effects associated with the hierarchical status enjoyed by women during a busy professional career also make it possible to approach the specific modalities of disinvesting the "work-object" and the "professional scene". Lastly -- since it is likely to upset both their grounding and the spheres conquered by women -- reaching retirement seems to fully reconvene some psychological problems inherent in adolescence work, sometimes providing the opportunity of deepening it. This thesis seeks to promote a reflection on working at cultural level and "setting up ways of sharing" its objects
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Siebold, Alexander Paul King. "Investigation into the role of Polycomb Repressive Complex 2 in the modulation of life span and stress resistance in Drosophila melanogaster." Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1274371273.
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GirÃo, Daniel de Castro. "Influence of sigma phase in the corrosion resistance of super duplex stainless steel ASTM A890 grade 1C after isothermal treatment." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=15245.
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The super duplex stainless steels are often used in applications where high mechanical strength is required, combined with corrosion resistance, especially in highly aggressive environments. However, when certain manufacturing processes are involved (hot forming or welding, for example) can occur the precipitation of undesirable phases, causing reduction of both mechanical properties as well as corrosion resistance. Particularly between 700 and 900 ÂC may occur sigma phase formation. This phase is responsible for the reduction of corrosion and mechanical resistance of super duplex steels. Through computer simulation in Thermo-CalC program, the phase diagram of ASTM A890 GRADE 1C super duplex stainless steel showed higher precipitated fraction of this phase in 830 ÂC temperature. Thus, this essay aims to evaluate the influence of isothermal treatment time in regards to this material aging, the corrosion resistance due to the formation of sigma phase. The evaluation of corrosion resistance was performed through open circuit potential monitoring, electrochemical impedance and potentiodynamic polarization tests (anodic branch) in 0.5 M H2SO4 solution, 0.5 M H2SO4 + 0.5M HCl and 0.5 M HCl at temperatures of 25, 35 and 45 ÂC. Additionally, a microstructural characterization of this material was performed by quantification phase through optical microscopy, morphological analysis by Scanning and Transmission Electron Microscopy, coupled techniques Electron backscattered diffraction and Electron Energy Dispersion Spectroscopy, and Vickers microhardness measures. The microstructural and morphological characterization confirmed the presence of sigma phase in super duplex stainless steel 1C and that the amount of this phase increases with aging heat treatment time. This phase showed a greater microhardness than the ferrite and austenite phases. The aging heat treatment influenced negatively on corrosion resistance of the steel when exposed to acidic solutions of H2SO4 and HCl at 25 ÂC, mainly when these are present in the same solution, probably due to their low pH. In this solution (H2SO4 + HCl), both increasing the aging heat treatment time as well as the temperature (35 and 45 ÂC), affects negatively the sample corrosion resistance, decreasing acoording a higher content of this phase.Os aÃos inoxidÃveis super duplex sÃo frequentemente utilizados em aplicaÃÃes onde à necessÃria uma grande resistÃncia mecÃnica, combinada a resistÃncia à corrosÃo, especialmente em ambientes de elevada agressividade. Entretanto, ao sofrer determinados processos de fabricaÃÃo (conformaÃÃo a quente ou soldagem, por exemplo), pode ocorrer à precipitaÃÃo de fases indesejÃveis, que causam tanto reduÃÃo de propriedades mecÃnicas quanto afetam a resistÃncia à corrosÃo. Particularmente entre 700 ÂC e 900 ÂC pode ocorrer à formaÃÃo de fase sigma. Esta fase à responsÃvel pela reduÃÃo da resistÃncia à corrosÃo e mecÃnica dos aÃos inoxidÃveis super duplex. Por meio de simulaÃÃo computacional no programa Thermo-CalCÂ, o diagrama de fases do aÃo inoxidÃvel super duplex ASTM A890 GRAU 1C apresentou maior fraÃÃo precipitada desta fase na temperatura de 830 ÂC. Assim, o presente trabalho tem por objetivo avaliar a influÃncia do tempo de tratamento isotÃrmico de envelhecimento deste material, na resistÃncia à corrosÃo devido à formaÃÃo da fase sigma. A avaliaÃÃo da resistÃncia à corrosÃo foi realizada por meio do monitoramento do potencial de circuito aberto, impedÃncia eletroquÃmica e de ensaios de polarizaÃÃo potenciodinÃmica (ramo anÃdico) em soluÃÃo de H2SO4 0,5 M, H2SO4 0,5 M + HCl 0,5 M e HCl 0,5 M, nas temperaturas de 25, 35 e 45 ÂC. Adicionalmente, foi realizada a caracterizaÃÃo microestrutural desse material atravÃs de quantificaÃÃo de fases por microscopia Ãtica, anÃlise morfolÃgica por Microscopia EletrÃnica de Varredura e TransmissÃo, acoplados as tÃcnicas de DifraÃÃo de ElÃtrons Retroespalhados e Espectroscopia de DispersÃo de Energia de ElÃtrons, alÃm de medidas de microdureza vickers. A caracterizaÃÃo microestrutural e morfolÃgica confirmou a presenÃa de fase sigma no aÃo inoxidÃvel super duplex 1C e que a quantidade desta fase aumenta com o tempo de tratamento tÃrmico de envelhecimento. Esta fase apresentou microdureza maior que as fases ferrita e austenita. O tratamento tÃrmico de envelhecimento influenciou de maneira negativa na resistÃncia a corrosÃo desse aÃo quando exposto a soluÃÃes Ãcidas de H2SO4 e HCl a 25 C, principalmente quando este estÃo presentes na mesma soluÃÃo, devido provavelmente ao seu baixo pH. Nesta soluÃÃo (H2SO4 + HCl), tanto o aumento do tempo de tratamento tÃrmico de envelhecimento quanto o aumento da temperatura (35 e 45 ÂC), afetam negativamente na resistÃncia à corrosÃo do material estudado, diminuindo à medida que se tem um maior conteÃdo de fase sigma.
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森脇, 隆仁. "線虫 Caenorhabditis elegans を用いたストレス応答機構に関する研究." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188521.
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Grünz, Gregor [Verfasser], Hannelore [Akademischer Betreuer] Daniel, Johann J. [Akademischer Betreuer] Hauner, and Martin [Akademischer Betreuer] Klingenspor. "Structure-activity relationship of selected flavonoids on aging and stress-resistance in Caenorhabditis elegans / Gregor Grünz. Gutachter: Hannelore Daniel ; Johann J. Hauner ; Martin Klingenspor. Betreuer: Hannelore Daniel." München : Universitätsbibliothek der TU München, 2012. http://d-nb.info/1024964000/34.
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