Theories Of Aging
Mostrando 13-24 de 24 artigos, teses e dissertações.
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13. A test of evolutionary theories of aging
Senescence is a nearly universal feature of multicellular organisms, and understanding why it occurs is a long-standing problem in biology. The two leading theories posit that aging is due to (i) pleiotropic genes with beneficial early-life effects but deleterious late-life effects (“antagonistic pleiotropy”) or (ii) mutations with purely deleterious lat
National Academy of Sciences.
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14. The aging process: major risk factor for disease and death.
Aging is the accumulation of changes responsible for the sequential alterations that accompany advancing age and the associated progressive increases in the chance of disease and death. Average life expectancies at birth in the developed countries are now approaching plateau values as the aging changes associated with the environment and disease near irreduc
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15. Aging and Cumulative Inequality: How Does Inequality Get Under the Skin?
Purpose: This article draws from cumulative disadvantage and life course theories to develop a new theory for the social scientific study of aging. Design and Methods: Five axioms of cumulative inequality (CI) theory are articulated to identify how life course trajectories are influenced by early and accumulated inequalities but can be modified by available
Oxford University Press.
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16. Reversal of the Mitochondrial Phenotype and Slow Development of Oxidative Biomarkers of Aging in Long-lived Mclk1+/− Mice*
Although there is a consensus that mitochondrial function is somehow linked to the aging process, the exact role played by mitochondria in this process remains unresolved. The discovery that reduced activity of the mitochondrial enzyme CLK-1/MCLK1 (also known as COQ7) extends lifespan in both Caenorhabditis elegans and mice has provided a genetic model to te
American Society for Biochemistry and Molecular Biology.
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17. Conditional tradeoffs between aging and organismal performance of Indy long-lived mutant flies
Alterations that extend the life span of animals and yeast typically involve decreases in metabolic rate, growth, physical activity, and/or early-life fecundity. This negative correlation between life span and the ability to assimilate and process energy, to move, grow, and reproduce, raises questions about the potential utility of life span extension. Trade
The National Academy of Sciences.
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18. Aging and primary care: an overview of organizational and behavioral issues in the delivery of healthcare services to older Americans.
An overview of (1) key trends shaping the healthcare environment and market; (2) ways in which these environmental trends are reflected in changes in the organization and delivery of healthcare; (3) the implications of environmental and organizational changes for older Americans; and (4) the research issues that can be addressed using organizational and beha
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19. High Consistency of Regional Cortical Thinning in Aging across Multiple Samples
Cross-sectional magnetic resonance imaging (MRI) studies of cortical thickness and volume have shown age effects on large areas, but there are substantial discrepancies across studies regarding the localization and magnitude of effects. These discrepancies hinder understanding of effects of aging on brain morphometry, and limit the potential usefulness of MR
Oxford University Press.
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20. Evidence for a programmed life span in a colonial protochordate.
The variety of theories that have attempted to define the mechanisms of aging and life span can be broadly divided into two alternative but nonexclusive viewpoints. The first stipulates that random changes of cellular and molecular structures lead to death following progressive "wear and tear." The second argues that life span is, at least in part, genetical
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21. Nonpharmacological amelioration of age-related learning deficits: The impact of hippocampal θ-triggered training
Age-related learning deficits are often attributed to deterioration of hippocampal function. Conversely, a well studied index of hippocampal activity, the θ rhythm, is known to enhance hippocampal plasticity and accelerate learning rate in young subjects, suggesting that manipulations of θ activity might be used as a means to counteract impairments related
National Academy of Sciences.
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22. The elasticity and failure of fluid-filled cellular solids: Theory and experiment
We extend and apply theories of filled foam elasticity and failure to recently available data on foods. The predictions of elastic modulus and failure mode dependence on internal pressure and on wall integrity are borne out by photographic evidence of distortion and failure under compressive loading and under the localized stress applied by a knife blade, an
The National Academy of Sciences.
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23. Thymine glycol and thymidine glycol in human and rat urine: a possible assay for oxidative DNA damage.
Thymine glycol is a DNA damage product of ionizing radiation and other oxidative mutagens. In an attempt to find a noninvasive assay for oxidative DNA damage in individuals, we have developed an HPLC assay for free thymine glycol and thymidine glycol in urine. Our results indicate that humans excrete about 32 nmol of the two glycols per day. Rats, which have
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24. Older plasma lipoproteins are more susceptible to oxidation: a linking mechanism for the lipid and oxidation theories of atherosclerotic cardiovascular disease.
Increases in plasma cholesterol are associated with progressive increases in the risk of atherosclerotic cardiovascular disease. In humans plasma cholesterol is contained primarily in apolipoprotein B-based low density lipoprotein (LDL). Cells stop making the high-affinity receptor responsible for LDL removal as they become cholesterol replete; this slows re