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Sample records for mechanisms underlying age-associated

  1. Mechanisms underlying the associations of maternal age with adverse perinatal outcomes

    DEFF Research Database (Denmark)

    Lawlor, Debbie A; Mortensen, Laust; Andersen, Anne-Marie Nybo

    2011-01-01

    The mechanisms underlying the association between maternal age (both young and older maternal age) and adverse perinatal outcomes are unclear. Methods We examined the association of maternal age at first birth with preterm birth (<37 weeks gestation) and small for gestational age (SGA) in a cohor...

  2. Cell-Nonautonomous Mechanisms Underlying Cellular and Organismal Aging.

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    Medkour, Younes; Svistkova, Veronika; Titorenko, Vladimir I

    2016-01-01

    Cell-autonomous mechanisms underlying cellular and organismal aging in evolutionarily distant eukaryotes have been established; these mechanisms regulate longevity-defining processes within a single eukaryotic cell. Recent findings have provided valuable insight into cell-nonautonomous mechanisms modulating cellular and organismal aging in eukaryotes across phyla; these mechanisms involve a transmission of various longevity factors between different cells, tissues, and organisms. Herein, we review such cell-nonautonomous mechanisms of aging in eukaryotes. We discuss the following: (1) how low molecular weight transmissible longevity factors modulate aging and define longevity of cells in yeast populations cultured in liquid media or on solid surfaces, (2) how communications between proteostasis stress networks operating in neurons and nonneuronal somatic tissues define longevity of the nematode Caenorhabditis elegans by modulating the rates of aging in different tissues, and (3) how different bacterial species colonizing the gut lumen of C. elegans define nematode longevity by modulating the rate of organismal aging. Copyright © 2016. Published by Elsevier Inc.

  3. Ageing mechanisms and associated lipid changes.

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    Kolovou, Genovefa; Katsiki, Niki; Pavlidis, Antonis; Bilianou, Helen; Goumas, George; Mikhailidis, Dimitri P

    2014-01-01

    Ageing is related to slowdown/breakdown of the somatotropic axis (i.e. the somatopause) leading to many physiological changes. The somatopause is accompanied by DNA and other macromolecule damage, and is characterized by a progressive decline in vitality and tissue function. We still do not have a definitive understanding of the mechanism( s) of ageing. Several overlapping theories have been proposed such as: 1) The free radical theory, 2) Mitochondrial Ageing, 3) The Glycation Theory, 4) Protein Damage and Maintenance in Ageing, and, 5) DNA Damage and Repair. Furthermore, several models of ageing were introduced such as genetically programmed senescence, telomere shortening, genomic instability, heterochromatin loss, altered epigenetic patterns and long lived cells. There are certain lipid modifications associated with the somatopause, characterized mainly by an increase in total cholesterol and triglyceride levels in both genders. In this review we consider the mechanisms of ageing and the associated changes in lipid metabolism according to gender.

  4. Molecular Mechanisms for Age-Associated Mitochondrial Deficiency in Skeletal Muscle

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    Akira Wagatsuma

    2012-01-01

    Full Text Available The abundance, morphology, and functional properties of mitochondria decay in skeletal muscle during the process of ageing. Although the precise mechanisms remain to be elucidated, these mechanisms include decreased mitochondrial DNA (mtDNA repair and mitochondrial biogenesis. Mitochondria possess their own protection system to repair mtDNA damage, which leads to defects of mtDNA-encoded gene expression and respiratory chain complex enzymes. However, mtDNA mutations have shown to be accumulated with age in skeletal muscle. When damaged mitochondria are eliminated by autophagy, mitochondrial biogenesis plays an important role in sustaining energy production and physiological homeostasis. The capacity for mitochondrial biogenesis has shown to decrease with age in skeletal muscle, contributing to progressive mitochondrial deficiency. Understanding how these endogenous systems adapt to altered physiological conditions during the process of ageing will provide a valuable insight into the underlying mechanisms that regulate cellular homeostasis. Here we will summarize the current knowledge about the molecular mechanisms responsible for age-associated mitochondrial deficiency in skeletal muscle. In particular, recent findings on the role of mtDNA repair and mitochondrial biogenesis in maintaining mitochondrial functionality in aged skeletal muscle will be highlighted.

  5. Shared molecular and cellular mechanisms of premature ageing and ageing-associated diseases.

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    Kubben, Nard; Misteli, Tom

    2017-10-01

    Ageing is the predominant risk factor for many common diseases. Human premature ageing diseases are powerful model systems to identify and characterize cellular mechanisms that underpin physiological ageing. Their study also leads to a better understanding of the causes, drivers and potential therapeutic strategies of common diseases associated with ageing, including neurological disorders, diabetes, cardiovascular diseases and cancer. Using the rare premature ageing disorder Hutchinson-Gilford progeria syndrome as a paradigm, we discuss here the shared mechanisms between premature ageing and ageing-associated diseases, including defects in genetic, epigenetic and metabolic pathways; mitochondrial and protein homeostasis; cell cycle; and stem cell-regenerative capacity.

  6. Age differences in the underlying mechanisms of stereotype threat effects.

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    Popham, Lauren E; Hess, Thomas M

    2015-03-01

    The goals of the present study were to (a) examine whether age differences exist in the mechanisms underlying stereotype threat effects on cognitive performance and (b) examine whether emotion regulation abilities may buffer against threat effects on performance. Older and younger adults were exposed to positive or negative age-relevant stereotypes, allowing us to examine the impact of threat on regulatory focus and working memory. Self-reported emotion regulation measures were completed prior to the session. Older adults' performance under threat suggested a prevention-focused approach to the task, indexed by increased accuracy and reduced speed. The same pattern was observed in younger adults, but the effects were not as strong. Age differences emerged when examining the availability of working memory resources under threat, with young adults showing decrements, whereas older adults did not. Emotion regulation abilities moderated threat effects in young adults but not in older adults. The results provide support for the notion that stereotype threat may lead to underperformance through somewhat different pathways in older and younger adults. Future research should further examine whether the underlying reason for this age difference is rooted in age-related improvements in emotion regulation. © The Author 2013. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  7. Temporomandibular disorders and painful comorbidities: clinical association and underlying mechanisms.

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    Costa, Yuri Martins; Conti, Paulo César Rodrigues; de Faria, Flavio Augusto Cardoso; Bonjardim, Leonardo Rigoldi

    2017-03-01

    The association between temporomandibular disorders (TMDs) and headaches, cervical spine dysfunction, and fibromyalgia is not artefactual. The aim of this review is to describe the comorbid relationship between TMD and these three major painful conditions and to discuss the clinical implications and the underlying pain mechanisms involved in these relationships. Common neuronal pathways and central sensitization processes are acknowledged as the main factors for the association between TMD and primary headaches, although the establishment of cause-effect mechanisms requires further clarification and characterization. The biomechanical aspects are not the main factors involved in the comorbid relationship between TMD and cervical spine dysfunction, which can be better explained by the neuronal convergence of the trigeminal and cervical spine sensory pathways as well as by central sensitization processes. The association between TMD and fibromyalgia also has supporting evidence in the literature, and the proposed main mechanism underlying this relationship is the impairment of the descending pain inhibitory system. In this particular scenario, a cause-effect relationship is more likely to occur in one direction, that is, fibromyalgia as a risk factor for TMD. Therefore, clinical awareness of the association between TMD and painful comorbidities and the support of multidisciplinary approaches are required to recognize these related conditions. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Reptile-associated salmonellosis in children aged under 5 years in South West England.

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    Murphy, Dan; Oshin, Femi

    2015-04-01

    To determine the proportion of Salmonella cases in children aged reptile-associated salmonellosis (RAS) and to compare the severity of illness. To analyse all cases of salmonellosis reported to public health authorities in children aged under 5 years in the South West of the UK from January 2010 to December 2013 for reptile exposure, age, serotype, hospitalisation and invasive disease. 48 of 175 (27%) Salmonella cases had exposure to reptiles. The median age of RAS cases was significantly lower than non-RAS cases (0.5 vs 1.0 year). RAS cases were 2.5 times more likely to be hospitalised (23/48) compared with non-RAS cases (25/127; p=0.0002). This trend continued in cases aged under 12 months, with significantly more RAS cases hospitalised (19/38) than non-RAS cases (8/42; p=0.003). Significantly more RAS cases had invasive disease (8/48: 5 bacteraemia, 2 meningitis, 1 colitis) than non-RAS cases (4/127: 3 bacteraemia, 1 meningitis). Reptile exposure was found in over a quarter of all reported Salmonella cases in children under 5 years of age. RAS is associated with young age, hospitalisation and invasive disease. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  9. Advanced paternal age effects in neurodevelopmental disorders-review of potential underlying mechanisms.

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    Janecka, M; Mill, J; Basson, M A; Goriely, A; Spiers, H; Reichenberg, A; Schalkwyk, L; Fernandes, C

    2017-01-31

    Multiple epidemiological studies suggest a relationship between advanced paternal age (APA) at conception and adverse neurodevelopmental outcomes in offspring, particularly with regard to increased risk for autism and schizophrenia. Conclusive evidence about how age-related changes in paternal gametes, or age-independent behavioral traits affect neural development is still lacking. Recent evidence suggests that the origins of APA effects are likely to be multidimensional, involving both inherited predisposition and de novo events. Here we provide a review of the epidemiological and molecular findings to date. Focusing on the latter, we present the evidence for genetic and epigenetic mechanisms underpinning the association between late fatherhood and disorder in offspring. We also discuss the limitations of the APA literature. We propose that different hypotheses relating to the origins of the APA effects are not mutually exclusive. Instead, multiple mechanisms likely contribute, reflecting the etiological complexity of neurodevelopmental disorders.

  10. DMPD: Mechanism of age-associated up-regulation in macrophage PGE2 synthesis. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15331118 Mechanism of age-associated up-regulation in macrophage PGE2 synthesis. Wu...e-associated up-regulation in macrophage PGE2 synthesis. PubmedID 15331118 Title Mechanism of age-associated... up-regulation in macrophage PGE2 synthesis. Authors Wu D, Meydani SN. Publicatio

  11. Changes in Structural-Mechanical Properties and Degradability of Collagen during Aging-associated Modifications*

    Science.gov (United States)

    Panwar, Preety; Lamour, Guillaume; Mackenzie, Neil C. W.; Yang, Heejae; Ko, Frank; Li, Hongbin; Brömme, Dieter

    2015-01-01

    During aging, changes occur in the collagen network that contribute to various pathological phenotypes in the skeletal, vascular, and pulmonary systems. The aim of this study was to investigate the consequences of age-related modifications on the mechanical stability and in vitro proteolytic degradation of type I collagen. Analyzing mouse tail and bovine bone collagen, we found that collagen at both fibril and fiber levels varies in rigidity and Young's modulus due to different physiological changes, which correlate with changes in cathepsin K (CatK)-mediated degradation. A decreased susceptibility to CatK-mediated hydrolysis of fibrillar collagen was observed following mineralization and advanced glycation end product-associated modification. However, aging of bone increased CatK-mediated osteoclastic resorption by ∼27%, and negligible resorption was observed when osteoclasts were cultured on mineral-deficient bone. We observed significant differences in the excavations generated by osteoclasts and C-terminal telopeptide release during bone resorption under distinct conditions. Our data indicate that modification of collagen compromises its biomechanical integrity and affects CatK-mediated degradation both in bone and tissue, thus contributing to our understanding of extracellular matrix aging. PMID:26224630

  12. Ageing under mechanical stress: first experiments for a silver based multilayer mirror

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    Lalo, Arnaud; Ravel, Guillaume; Ignat, Michel; Cousin, Bernard; Swain, Michael V.

    2017-11-01

    Improving materials and devices reliability is a major concern to the spatial industry. Results are reported for satellite mirrors-like specimens consisting in oxide-protected metal systems. Optical coatings were deposited by electron beam evaporation. Mechanical stress fields in multi-layered materials play an important role. The stress state can have far-reaching implications both in kinetics and thermodynamics. Therefore an integrated apparatus with four-point bending equipment was designed. The technique allowed us to exert stress into a film or a system of films on a substrate concurrently with thermal treatment. In order to achieve the first tests performed with the help of the apparatus, various preliminary characterizations were required. The article reports the preliminary micro-mechanical testing of the materials (ultra micro-indentation to evaluate the elastic modulus of the samples materials and wafer curvature technique to determine the specimen residual stress) and the first ageing experiment. Experimental evidence of accelerated ageing under stress is successfully reported.

  13. Failure of delayed nonsynaptic neuronal plasticity underlies age-associated long-term associative memory impairment

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    Watson Shawn N

    2012-08-01

    Full Text Available Abstract Background Cognitive impairment associated with subtle changes in neuron and neuronal network function rather than widespread neuron death is a feature of the normal aging process in humans and animals. Despite its broad evolutionary conservation, the etiology of this aging process is not well understood. However, recent evidence suggests the existence of a link between oxidative stress in the form of progressive membrane lipid peroxidation, declining neuronal electrical excitability and functional decline of the normal aging brain. The current study applies a combination of behavioural and electrophysiological techniques and pharmacological interventions to explore this hypothesis in a gastropod model (Lymnaea stagnalis feeding system that allows pinpointing the molecular and neurobiological foundations of age-associated long-term memory (LTM failure at the level of individual identified neurons and synapses. Results Classical appetitive reward-conditioning induced robust LTM in mature animals in the first quartile of their lifespan but failed to do so in animals in the last quartile of their lifespan. LTM failure correlated with reduced electrical excitability of two identified serotonergic modulatory interneurons (CGCs critical in chemosensory integration by the neural network controlling feeding behaviour. Moreover, while behavioural conditioning induced delayed-onset persistent depolarization of the CGCs known to underlie appetitive LTM formation in this model in the younger animals, it failed to do so in LTM-deficient senescent animals. Dietary supplementation of the lipophilic anti-oxidant α-tocopherol reversed the effect of age on CGCs electrophysiological characteristics but failed to restore appetitive LTM function. Treatment with the SSRI fluoxetine reversed both the neurophysiological and behavioural effects of age in senior animals. Conclusions The results identify the CGCs as cellular loci of age-associated appetitive

  14. Phospholipase A2 - nexus of aging, oxidative stress, neuronal excitability, and functional decline of the aging nervous system? Insights from a snail model system of neuronal aging and age-associated memory impairment.

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    Hermann, Petra M; Watson, Shawn N; Wildering, Willem C

    2014-01-01

    The aging brain undergoes a range of changes varying from subtle structural and physiological changes causing only minor functional decline under healthy normal aging conditions, to severe cognitive or neurological impairment associated with extensive loss of neurons and circuits due to age-associated neurodegenerative disease conditions. Understanding how biological aging processes affect the brain and how they contribute to the onset and progress of age-associated neurodegenerative diseases is a core research goal in contemporary neuroscience. This review focuses on the idea that changes in intrinsic neuronal electrical excitability associated with (per)oxidation of membrane lipids and activation of phospholipase A2 (PLA2) enzymes are an important mechanism of learning and memory failure under normal aging conditions. Specifically, in the context of this special issue on the biology of cognitive aging we portray the opportunities offered by the identifiable neurons and behaviorally characterized neural circuits of the freshwater snail Lymnaea stagnalis in neuronal aging research and recapitulate recent insights indicating a key role of lipid peroxidation-induced PLA2 as instruments of aging, oxidative stress and inflammation in age-associated neuronal and memory impairment in this model system. The findings are discussed in view of accumulating evidence suggesting involvement of analogous mechanisms in the etiology of age-associated dysfunction and disease of the human and mammalian brain.

  15. Phospholipase A2 - nexus of aging, oxidative stress, neuronal excitability and functional decline of the aging nervous system? Insights from a snail model system of neuronal aging and age-associated memory impairment.

    Directory of Open Access Journals (Sweden)

    Petra Maria Hermann

    2014-12-01

    Full Text Available TThe aging brain can undergo a range of changes varying from subtle structural and physiological changes causing only minor functional decline under healthy normal aging conditions, to severe cognitive or neurological impairment associated with extensive loss of neurons and circuits due to age-associated neurodegenerative disease conditions. Understanding how biological aging processes affect the brain and how they contribute to the onset and progress of age-associated neurodegenerative diseases is a core research goal in contemporary neuroscience. This review focuses on the idea that changes in intrinsic neuronal electrical excitability associated with (peroxidation of membrane lipids and activation of phospholipase A2 (PLA2 enzymes are an important mechanism of learning and memory failure under normal aging conditions. Specifically, in the context of this special issue on the Biology of cognitive aging we (1 portray the opportunities offered by the identifiable neurons and behaviorally characterized neural circuits of the freshwater snail Lymnaea stagnalis in neuronal aging research and (2 recapitulate recent insights indicating a key role of lipid peroxidation-induced PLA2 as instruments of aging, oxidative stress and inflammation in age-associated neuronal and memory impairment in this model system. The findings are discussed in view of accumulating evidence suggesting involvement of analogous mechanisms in the etiology of age-associated dysfunction and disease of the human and mammalian brain.

  16. Mechanisms Underlying the Anti-Aging and Anti-Tumor Effects of Lithocholic Bile Acid

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    Anthony Arlia-Ciommo

    2014-09-01

    Full Text Available Bile acids are cholesterol-derived bioactive lipids that play essential roles in the maintenance of a heathy lifespan. These amphipathic molecules with detergent-like properties display numerous beneficial effects on various longevity- and healthspan-promoting processes in evolutionarily distant organisms. Recent studies revealed that lithocholic bile acid not only causes a considerable lifespan extension in yeast, but also exhibits a substantial cytotoxic effect in cultured cancer cells derived from different tissues and organisms. The molecular and cellular mechanisms underlying the robust anti-aging and anti-tumor effects of lithocholic acid have emerged. This review summarizes the current knowledge of these mechanisms, outlines the most important unanswered questions and suggests directions for future research.

  17. The Role of Exercise in Cardiac Aging: From Physiology to Molecular Mechanisms.

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    Roh, Jason; Rhee, James; Chaudhari, Vinita; Rosenzweig, Anthony

    2016-01-22

    Aging induces structural and functional changes in the heart that are associated with increased risk of cardiovascular disease and impaired functional capacity in the elderly. Exercise is a diagnostic and therapeutic tool, with the potential to provide insights into clinical diagnosis and prognosis, as well as the molecular mechanisms by which aging influences cardiac physiology and function. In this review, we first provide an overview of how aging impacts the cardiac response to exercise, and the implications this has for functional capacity in older adults. We then review the underlying molecular mechanisms by which cardiac aging contributes to exercise intolerance, and conversely how exercise training can potentially modulate aging phenotypes in the heart. Finally, we highlight the potential use of these exercise models to complement models of disease in efforts to uncover new therapeutic targets to prevent or treat heart disease in the aging population. © 2016 American Heart Association, Inc.

  18. Contribution of the D-Serine-dependent pathway to the cellular mechanisms underlying cognitive aging

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    Emilie Rouaud

    2010-02-01

    Full Text Available An association between age-related memory impairments and changes in functional plasticity in the aging brain has been under intense study within the last decade. In this article, we show that an impaired activation of the strychnine-insensitive glycine site of N-Methyl-D-Aspartate receptors (NMDA-R by its agonist D-serine contributes to deficits of synaptic plasticity in the hippocampus of memory-impaired aged rats. Supplementation with exogenous D-serine prevents the age-related deficits of isolated NMDA-R-dependent synaptic potentials as well as those of theta-burst-induced long-term potentiation and synaptic depotentiation. Endogenous levels of D-serine are reduced in the hippocampus with aging, that correlates with a weaker expression of serine racemase synthesizing the amino acid. On the contrary, the affinity of D-serine binding to NMDA-R is not affected by aging. These results point to a critical role for the D-serine-dependent pathway in the functional alterations of the brain underlying memory impairment and provide key information in the search for new therapeutic strategies for the treatment of memory deficits in the elderly.

  19. Age-related differences in associative memory: the role of sensory decline.

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    Naveh-Benjamin, Moshe; Kilb, Angela

    2014-09-01

    Numerous studies show age-related decline in episodic memory. One of the explanations for this decline points to older adults' deficit in associative memory, reflecting the difficulties they have in binding features of episodes into cohesive entities and retrieving these bindings. Here, we evaluate the degree to which this deficit may be mediated by sensory loss associated with increased age. In 2 experiments, young adults studied word pairs that were degraded at encoding either visually (Experiment 1) or auditorily (Experiment 2). We then tested their memory for both the component words and the associations with recognition tests. For both experiments, young adults under nondegraded conditions showed an advantage in associative over item memory, relative to a group of older adults. In contrast, under perceptually degraded conditions younger adults performed similarly to the older adults who were tested under nondegraded conditions. More specifically, under perceptual degradation, young adults' associative memory declined and their component memory improved somewhat, resulting in an associative deficit, similar to that shown by older adults. This evidence is consistent with a sensory acuity decline in old age being one mediator in the associative deficit of older adults. These results broaden our understanding of age-related memory changes and how sensory and cognitive processes interact to shape these changes. The theoretical implications of these results are discussed with respect to mechanisms underlying age-related changes in episodic memory and resource tradeoffs in the encoding of component and associative memory. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  20. Mechanisms of the anorexia of aging-a review.

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    Wysokiński, Adam; Sobów, Tomasz; Kłoszewska, Iwona; Kostka, Tomasz

    2015-08-01

    Many, even healthy, older people fail to adequately regulate food intake and experience loss of weight. Aging-associated changes in the regulation of appetite and the lack of hunger have been termed as the anorexia of aging. The etiology of the anorexia of aging is multi-factorial and includes a combination of physiological changes associated with aging (decline in smell and taste, reduced central and peripheral drive to eat, delayed gastric emptying), pathological conditions (depression, dementia, somatic diseases, medications and iatrogenic interventions, oral-health status), and social factors (poverty, loneliness). However, exact mechanisms of the anorexia of aging remain to be elucidated. Many neurobiological mechanisms may be secondary to age-related changes in body composition and not associated with anorexia per se. Therefore, further studies on pathophysiological mechanisms of the anorexia of aging should employ accurate measurement of body fat and lean mass. The anorexia of aging is associated with protein-energy malnutrition, sarcopenia, frailty, functional deterioration, morbidity, and mortality. Since this symptom can lead to dramatic consequences, early identification and effective interventions are needed. One of the most important goals in the geriatric care is to optimize nutritional status of the elderly.

  1. Buffering mechanisms in aging: a systems approach toward uncovering the genetic component of aging.

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    Aviv Bergman

    2007-08-01

    Full Text Available An unrealized potential to understand the genetic basis of aging in humans, is to consider the immense survival advantage of the rare individuals who live 100 years or more. The Longevity Gene Study was initiated in 1998 at the Albert Einstein College of Medicine to investigate longevity genes in a selected population: the "oldest old" Ashkenazi Jews, 95 years of age and older, and their children. The study proved the principle that some of these subjects are endowed with longevity-promoting genotypes. Here we reason that some of the favorable genotypes act as mechanisms that buffer the deleterious effect of age-related disease genes. As a result, the frequency of deleterious genotypes may increase among individuals with extreme lifespan because their protective genotype allows disease-related genes to accumulate. Thus, studies of genotypic frequencies among different age groups can elucidate the genetic determinants and pathways responsible for longevity. Borrowing from evolutionary theory, we present arguments regarding the differential survival via buffering mechanisms and their target age-related disease genes in searching for aging and longevity genes. Using more than 1,200 subjects between the sixth and eleventh decades of life (at least 140 subjects in each group, we corroborate our hypotheses experimentally. We study 66 common allelic site polymorphism in 36 candidate genes on the basis of their phenotype. Among them we have identified a candidate-buffering mechanism and its candidate age-related disease gene target. Previously, the beneficial effect of an advantageous cholesteryl ester transfer protein (CETP-VV genotype on lipoprotein particle size in association with decreased metabolic and cardiovascular diseases, as well as with better cognitive function, have been demonstrated. We report an additional advantageous effect of the CETP-VV (favorable genotype in neutralizing the deleterious effects of the lipoprotein(a (LPA gene

  2. Age-related mechanical strength evolution of trabecular bone under fatigue damage for both genders: Fracture risk evaluation.

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    Ben Kahla, Rabeb; Barkaoui, Abdelwahed; Merzouki, Tarek

    2018-05-04

    Bone tissue is a living composite material, providing mechanical and homeostatic functions, and able to constantly adapt its microstructure to changes in long term loading. This adaptation is conducted by a physiological process, known as "bone remodeling". This latter is manifested by interactions between osteoclasts and osteoblasts, and can be influenced by many local factors, via effects on bone cell differentiation and proliferation. In the current work, age and gender effects on damage rate evolution, throughout life, have been investigated using a mechanobiological finite element modeling. To achieve the aim, a mathematical model has been developed, coupling both cell activities and mechanical behavior of trabecular bone, under cyclic loadings. A series of computational simulations (ABAQUS/UMAT) has been performed on a 3D human proximal femur, allowing to investigate the effects of mechanical and biological parameters on mechanical strength of trabecular bone, in order to evaluate the fracture risk resulting from fatigue damage. The obtained results revealed that mechanical stimulus amplitude affects bone resorption and formation rates, and indicated that age and gender are major factors in bone response to the applied loadings. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Age-related similarities and differences in brain activity underlying reversal learning

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    Kaoru eNashiro

    2013-05-01

    Full Text Available The ability to update associative memory is an important aspect of episodic memory and a critical skill for social adaptation. Previous research with younger adults suggests that emotional arousal alters brain mechanisms underlying memory updating; however, it is unclear whether this applies to older adults. Given that the ability to update associative information declines with age, it is important to understand how emotion modulates the brain processes underlying memory updating in older adults. The current study investigated this question using reversal learning tasks, where younger and older participants (age ranges 19-35 and 61-78 respectively learn a stimulus–outcome association and then update their response when contingencies change. We found that younger and older adults showed similar patterns of activation in the frontopolar OFC and the amygdala during emotional reversal learning. In contrast, when reversal learning did not involve emotion, older adults showed greater parietal cortex activity than did younger adults. Thus, younger and older adults show more similarities in brain activity during memory updating involving emotional stimuli than during memory updating not involving emotional stimuli.

  4. Cognitive Mechanisms Underlying Directional and Non-directional Spatial-Numerical Associations across the Lifespan

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    Manuel Ninaus

    2017-08-01

    Full Text Available There is accumulating evidence suggesting an association of numbers with physical space. However, the origin of such spatial-numerical associations (SNAs is still debated. In the present study we investigated the development of two SNAs in a cross-sectional study involving children, young and middle-aged adults as well as the elderly: (1 the SNARC (spatial-numerical association of response codes effect, reflecting a directional SNA; and (2 the numerical bisection bias in a line bisection task with numerical flankers. Results revealed a consistent SNARC effect in all age groups that continuously increased with age. In contrast, a numerical bisection bias was only observed for children and elderly participants, implying an U-shaped distribution of this bias across age groups. Additionally, individual SNARC effects and numerical bisection biases did not correlate significantly. We argue that the SNARC effect seems to be influenced by longer-lasting experiences of cultural constraints such as reading and writing direction and may thus reflect embodied representations. Contrarily, the numerical bisection bias may originate from insufficient inhibition of the semantic influence of irrelevant numerical flankers, which should be more pronounced in children and elderly people due to development and decline of cognitive control, respectively. As there is an ongoing debate on the origins of SNAs in general and the SNARC effect in particular, the present results are discussed in light of these differing accounts in an integrative approach. However, taken together, the present pattern of results suggests that different cognitive mechanisms underlie the SNARC effect and the numerical bisection bias.

  5. Phosphodiesterase 1 regulation is a key mechanism in vascular aging

    DEFF Research Database (Denmark)

    Niño, Paula K Bautista; Durik, Matej; Danser, A H Jan

    2015-01-01

    Reduced nitric oxide (NO)/cGMP signalling is observed in age-related vascular disease. We hypothesize that this disturbed signalling involves effects of genomic instability, a primary causal factor in aging, on vascular smooth muscle cells (VSMCs) and that the underlying mechanism plays a role...... in human age-related vascular disease. To test our hypothesis, we combined experiments in mice with genomic instability resulting from the defective nucleotide excision repair gene ERCC1 (Ercc1(d/-) mice), human VSMC cultures and population genome-wide association studies (GWAS). Aortic rings of Ercc1(d...... in lungs was higher in Ercc1(d/-) mice. No differences in activity or levels of cGMP-dependent protein kinase 1 or sGC were observed in Ercc1(d/-) mice compared with WT. Senescent human VSMC showed elevated PDE1A and PDE1C and PDE5 mRNA levels (11.6-, 9- and 2.3-fold respectively), which associated...

  6. Conservative fluid management prevents age-associated ventilator induced mortality.

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    Herbert, Joseph A; Valentine, Michael S; Saravanan, Nivi; Schneck, Matthew B; Pidaparti, Ramana; Fowler, Alpha A; Reynolds, Angela M; Heise, Rebecca L

    2016-08-01

    Approximately 800 thousand patients require mechanical ventilation in the United States annually with an in-hospital mortality rate of over 30%. The majority of patients requiring mechanical ventilation are over the age of 65 and advanced age is known to increase the severity of ventilator-induced lung injury (VILI) and in-hospital mortality rates. However, the mechanisms which predispose aging ventilator patients to increased mortality rates are not fully understood. Ventilation with conservative fluid management decreases mortality rates in acute respiratory distress patients, but to date there has been no investigation of the effect of conservative fluid management on VILI and ventilator associated mortality rates. We hypothesized that age-associated increases in susceptibility and incidence of pulmonary edema strongly promote age-related increases in ventilator associated mortality. 2month old and 20month old male C57BL6 mice were mechanically ventilated with either high tidal volume (HVT) or low tidal volume (LVT) for up to 4h with either liberal or conservative fluid support. During ventilation, lung compliance, total lung capacity, and hysteresis curves were quantified. Following ventilation, bronchoalveolar lavage fluid was analyzed for total protein content and inflammatory cell infiltration. Wet to dry ratios were used to directly measure edema in excised lungs. Lung histology was performed to quantify alveolar barrier damage/destruction. Age matched non-ventilated mice were used as controls. At 4h, both advanced age and HVT ventilation significantly increased markers of inflammation and injury, degraded pulmonary mechanics, and decreased survival rates. Conservative fluid support significantly diminished pulmonary edema and improved pulmonary mechanics by 1h in advanced age HVT subjects. In 4h ventilations, conservative fluid support significantly diminished pulmonary edema, improved lung mechanics, and resulted in significantly lower mortality rates in

  7. ACTIVATION MECHANISMS OF GUT-ASSOCIATED LYMPHOID TISSUE UNDER CHRONIC SOCIAL STRESS CONDITIONS

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    A. M. Kamyshnyi

    2015-01-01

    Full Text Available Stress-induced immune disregulation is a risk factor of autoimmune and inflammatory diseases, but, so far, the mechanisms for this effect are not fully known. Expression levels of specific mRNAs were assessed in gut-associated lymphoid tissue (GALT from Wistar rats subjected to chronic social stress (CSS. Gene expression was evaluated for NR3C1, Adrβ2, as well as IL-1β, IL-17α pro-inflammatory cytokines, and Nlrp, an inflammasome gene. Under the CSS conditions, we have shown altered distribution of RORγt +, FoxP3+, LMP2+, XBP1+ lymphocytes in GALT.The experiments were carried out with female Wistar rats aged 5–6 months. Specific mRNA expression for the target genes was determined by means of real-time PCR performed in a CFX96™ thermocycler («BioRadLaboratories, Inc»,USA. Relative levels of a target gene expression were quantified by the ΔΔCt method, being compared with rat GAPDH reference gene expression. Statistical analysis was performed with available «BioRad СFX Manager 3.1» software. Specific monoclonal rat antibodes were used for detection of immunopositive lymphocytes by means of indirect immunofluorescence technique.CSS development leads to decreased levels of mRNA expression for Nr3c1 and Adrβ2-genes in the GALT cells, being accompanied with unidirectional changes, i.e., increased transcription of pro-inflammatory cytokine mRNAs (IL-1β, IL-17α and Nlrp3-inflammasome genes. These changes are accompanied by decreased FoxP3+/RORγt + cell ratio and predominant Th17 differentiation accompanied by suppressor failure. In addition, CSS development was characterized by unidirectional tendency for increasing total number of LMP2+ lymphocytes and reduced ХВР1+ cell population density in lymphoid structures of rat ileum.The events observed in GALT cell populations under CSS conditions are opposing classical paradigm of the stress response. The CSS-associated effects do not promote immunosuppression, however, are able to cause

  8. Age influences the skin reaction pattern to mechanical stress and its repair level through skin care products.

    Science.gov (United States)

    Zouboulis, Christos C; Elewa, Rana; Ottaviani, Monica; Fluhr, Joachim; Picardo, Mauro; Bernois, Armand; Heusèle, Catherine; Camera, Emanuela

    2018-03-01

    Skin aging is associated with alterations of surface texture, sebum composition and immune response. Mechanical stress induces repair mechanisms, which may be dependent on the age and quality of the skin. The response to mechanical stress in young and aged individuals, their subjective opinion and the objective effectiveness of skin care products were evaluated by biophysical skin quality parameters (stratum corneum hydration, transepidermal water loss, skin pH, pigmentation and erythema) at baseline, 1, 6, 24h and 7days at the forearms of 2 groups of healthy volunteers, younger than 35 years (n=11) and older than 60 years (n=13). In addition, casual surface lipid composition was studied under the same conditions at the baseline and day 7 after mechanical stress induction. Evaluations were also performed in stressed skin areas treated daily with skin care products and the subjective opinion of the volunteers was additionally documented. The tested groups exhibited age-associated baseline skin functions as well as casual surface lipid composition and different reaction patterns to mechanical stress. Skin care was more effective in normalizing skin reaction to stress in the young than in the aged group. The subjective volunteer opinion correlated with the objective measurements. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Music and Memory in Alzheimer's Disease and The Potential Underlying Mechanisms.

    Science.gov (United States)

    Peck, Katlyn J; Girard, Todd A; Russo, Frank A; Fiocco, Alexandra J

    2016-01-01

    With population aging and a projected exponential expansion of persons diagnosed with Alzheimer's disease (AD), the development of treatment and prevention programs has become a fervent area of research and discovery. A growing body of evidence suggests that music exposure can enhance memory and emotional function in persons with AD. However, there is a paucity of research that aims to identify specific underlying neural mechanisms associated with music's beneficial effects in this particular population. As such, this paper reviews existing anecdotal and empirical evidence related to the enhancing effects of music exposure on cognitive function and further provides a discussion on the potential underlying mechanisms that may explain music's beneficial effect. Specifically, this paper will outline the potential role of the dopaminergic system, the autonomic nervous system, and the default network in explaining how music may enhance memory function in persons with AD.

  10. Effect of aging on the tribological and mechanical properties of a high-nitrogen stainless austenitic steel

    International Nuclear Information System (INIS)

    Korshunov, L.G.; Chernenko, N.L.; Tereshchenko, N.A.; Uvarov, A.I.

    2005-01-01

    The effect of aging, associated with predominant precipitation of vanadium nitrides (VN), on tribological and mechanical properties of austenitic steel 10Kh18AG18N5MF hardened from 1100 Deg C is studied. Metallographic, X-ray diffraction and electron microscopical methods are used to study structural transformations proceeding in the steel on aging as well as on friction loading under conditions of dry slipping friction in steel-abrasive and steel-steel pairs. It is shown that the aging at temperatures of 600-700 Deg C resulting in a considerable increase of strength properties of the steel demonstrates a relatively weak positive effect on steel resistance to abrasive and adhesive wear. It is stated that the use of aging by continuous mechanism permits attaining favourable mechanical and tribological properties in vanadium-alloying nitrogen-bearing austenitic steels [ru

  11. Modification of the microstructure of a weld of the same composition as X 20 CrMoV 12 1 by means of purely thermal aging and by aging under mechanical stress at 550 C

    International Nuclear Information System (INIS)

    Deimel, P.; Hoffmann, M.; Kuppler, D.

    1991-01-01

    The experiments were to contribute deeper insight into the mechanisms and effects induced by long-term, purely thermal aging and by aging over the same period under mechanical stress in a weld of the same composition as X 20 CrMoV 12 1, which are known to cause microstructural changes resulting in modified toughness of the weld. (orig.) [de

  12. Osteopontin attenuates aging-associated phenotypes of hematopoietic stem cells.

    Science.gov (United States)

    Guidi, Novella; Sacma, Mehmet; Ständker, Ludger; Soller, Karin; Marka, Gina; Eiwen, Karina; Weiss, Johannes M; Kirchhoff, Frank; Weil, Tanja; Cancelas, Jose A; Florian, Maria Carolina; Geiger, Hartmut

    2017-04-03

    Upon aging, hematopoietic stem cells (HSCs) undergo changes in function and structure, including skewing to myeloid lineages, lower reconstitution potential and loss of protein polarity. While stem cell intrinsic mechanisms are known to contribute to HSC aging, little is known on whether age-related changes in the bone marrow niche regulate HSC aging. Upon aging, the expression of osteopontin (OPN) in the murine bone marrow stroma is reduced. Exposure of young HSCs to an OPN knockout niche results in a decrease in engraftment, an increase in long-term HSC frequency and loss of stem cell polarity. Exposure of aged HSCs to thrombin-cleaved OPN attenuates aging of old HSCs, resulting in increased engraftment, decreased HSC frequency, increased stem cell polarity and a restored balance of lymphoid and myeloid cells in peripheral blood. Thus, our data suggest a critical role for reduced stroma-derived OPN for HSC aging and identify thrombin-cleaved OPN as a novel niche informed therapeutic approach for ameliorating HSC phenotypes associated with aging. © 2017 The Authors. Published under the terms of the CC BY NC ND 4.0 license.

  13. Poor cognitive ageing: Vulnerabilities, mechanisms and the impact of nutritional interventions.

    Science.gov (United States)

    Miquel, Sophie; Champ, Claire; Day, Jon; Aarts, Esther; Bahr, Ben A; Bakker, Martijntje; Bánáti, Diána; Calabrese, Vittorio; Cederholm, Tommy; Cryan, John; Dye, Louise; Farrimond, Jonathan A; Korosi, Aniko; Layé, Sophie; Maudsley, Stuart; Milenkovic, Dragan; Mohajeri, M Hasan; Sijben, John; Solomon, Alina; Spencer, Jeremy P E; Thuret, Sandrine; Vanden Berghe, Wim; Vauzour, David; Vellas, Bruno; Wesnes, Keith; Willatts, Peter; Wittenberg, Raphael; Geurts, Lucie

    2018-03-01

    Ageing is a highly complex process marked by a temporal cascade of events, which promote alterations in the normal functioning of an individual organism. The triggers of normal brain ageing are not well understood, even less so the factors which initiate and steer the neuronal degeneration, which underpin disorders such as dementia. A wealth of data on how nutrients and diets may support cognitive function and preserve brain health are available, yet the molecular mechanisms underlying their biological action in both normal ageing, age-related cognitive decline, and in the development of neurodegenerative disorders have not been clearly elucidated. This review aims to summarise the current state of knowledge of vulnerabilities that predispose towards dysfunctional brain ageing, highlight potential protective mechanisms, and discuss dietary interventions that may be used as therapies. A special focus of this paper is on the impact of nutrition on neuroprotection and the underlying molecular mechanisms, and this focus reflects the discussions held during the 2nd workshop 'Nutrition for the Ageing Brain: Functional Aspects and Mechanisms' in Copenhagen in June 2016. The present review is the most recent in a series produced by the Nutrition and Mental Performance Task Force under the auspice of the International Life Sciences Institute Europe (ILSI Europe). Coupling studies of cognitive ageing with studies investigating the effect of nutrition and dietary interventions as strategies targeting specific mechanisms, such as neurogenesis, protein clearance, inflammation, and non-coding and microRNAs is of high value. Future research on the impact of nutrition on cognitive ageing will need to adopt a longitudinal approach and multimodal nutritional interventions will likely need to be imposed in early-life to observe significant impact in older age. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  14. Biosystems Study of the Molecular Networks Underlying Hippocampal Aging Progression and Anti-aging Treatment in Mice

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    Jiao Wang

    2017-12-01

    Full Text Available Aging progression is a process that an individual encounters as they become older, and usually results from a series of normal physiological changes over time. The hippocampus, which contributes to the loss of spatial and episodic memory and learning in older people, is closely related to the detrimental effects of aging at the morphological and molecular levels. However, age-related genetic changes in hippocampal molecular mechanisms are not yet well-established. To provide additional insight into the aging process, differentially-expressed genes of 3- versus 24- and 29-month old mice were re-analyzed. The results revealed that a large number of immune and inflammatory response-related genes were up-regulated in the aged hippocampus, and membrane receptor-associated genes were down-regulated. The down-regulation of transmembrane receptors may indicate the weaker perception of environmental exposure in older people, since many transmembrane proteins participate in signal transduction. In addition, molecular interaction analysis of the up-regulated immune genes indicated that the hub gene, Ywhae, may play essential roles in immune and inflammatory responses during aging progression, as well as during hippocampal development. Our biological experiments confirmed the conserved roles of Ywhae and its partners between human and mouse. Furthermore, comparison of microarray data between advanced-age mice treated with human umbilical cord blood plasma protein and the phosphate-buffered saline control showed that the genes that contribute to the revitalization of advanced-age mice are different from the genes induced by aging. These results implied that the revitalization of advanced-age mice is not a simple reverse process of normal aging progression. Our data assigned novel roles of genes during aging progression and provided further theoretic evidence for future studies exploring the underlying mechanisms of aging and anti-aging-related disease

  15. Molecular mechanisms of renal aging.

    Science.gov (United States)

    Schmitt, Roland; Melk, Anette

    2017-09-01

    Epidemiologic, clinical, and molecular evidence suggest that aging is a major contributor to the increasing incidence of acute kidney injury and chronic kidney disease. The aging kidney undergoes complex changes that predispose to renal pathology. The underlying molecular mechanisms could be the target of therapeutic strategies in the future. Here, we summarize recent insight into cellular and molecular processes that have been shown to contribute to the renal aging phenotype.The main clinical finding of renal aging is the decrease in glomerular filtration rate, and its structural correlate is the loss of functioning nephrons. Mechanistically, this has been linked to different processes, such as podocyte hypertrophy, glomerulosclerosis, tubular atrophy, and gradual microvascular rarefaction. Renal functional recovery after an episode of acute kidney injury is significantly worse in elderly patients. This decreased regenerative potential, which is a hallmark of the aging process, may be caused by cellular senescence. Accumulation of senescent cells could explain insufficient repair and functional loss, a view that has been strengthened by recent studies showing that removal of senescent cells results in attenuation of renal aging. Other potential mechanisms are alterations in autophagy as an important component of a disturbed renal stress response and functional differences in the inflammatory system. Promising therapeutic measures to counteract these age-related problems include mimetics of caloric restriction, pharmacologic renin-angiotensin-aldosterone system inhibition, and novel strategies of senotherapy with the goal of reducing the number of senescent cells to decrease aging-related disease in the kidney. Copyright © 2017 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

  16. Age-associated impairments in contraction-induced rapid-onset vasodilatation within the forearm are independent of mechanical factors.

    Science.gov (United States)

    Hughes, William E; Kruse, Nicholas T; Casey, Darren P

    2018-05-01

    What is the central question of this study? We examined whether the mechanical contribution to contraction-induced rapid-onset vasodilatation (ROV) differed with age and whether ROV is associated with peripheral artery stiffness. Furthermore, we examined how manipulation of perfusion pressure modulates ROV in young and older adults. What is the main finding and its importance? The mechanical contribution to ROV is similar in young and older adults. Conversely, peripheral arterial stiffness is not associated with ROV. Enhancing perfusion pressure augments ROV to a similar extent in young and older adults. These results suggest that age-related attenuations in ROV are not attributable to a mechanical component and that ROV responses are independent of peripheral artery stiffness. Contraction-induced rapid-onset vasodilatation (ROV) is modulated by perfusion and transmural pressure in young adults; however, this effect remains unknown in older adults. The present study examined the mechanical contribution to ROV in young versus older adults, the influence of perfusion pressure and whether these responses are associated with arterial stiffness. Forearm vascular conductance (in millilitres per minute per 100 mmHg) was measured in 12 healthy young (24 ± 4 years old) and 12 older (67 ± 3 years old) adults during: (i) single dynamic contractions at 20% of maximal voluntary contraction; and (ii) single external mechanical compression of the forearm (200 mmHg) positioned above, at and below heart level. Carotid-radial pulse-wave velocity characterized upper limb arterial stiffness. Total ROV responses to single muscle contractions and single external mechanical compressions were attenuated in older adults at heart level (P mechanical contribution to contraction-induced peak (46 ± 14 versus 40 ± 18%; P = 0.21) and total (37 ± 21 versus 32 ± 18%; P = 0.27) responses were not different between young and older adults. Reducing or enhancing perfusion

  17. Aging Mechanisms of Electrode Materials in Lithium-Ion Batteries for Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Cheng Lin

    2015-01-01

    Full Text Available Electrode material aging leads to a decrease in capacity and/or a rise in resistance of the whole cell and thus can dramatically affect the performance of lithium-ion batteries. Furthermore, the aging phenomena are extremely complicated to describe due to the coupling of various factors. In this review, we give an interpretation of capacity/power fading of electrode-oriented aging mechanisms under cycling and various storage conditions for metallic oxide-based cathodes and carbon-based anodes. For the cathode of lithium-ion batteries, the mechanical stress and strain resulting from the lithium ions insertion and extraction predominantly lead to structural disordering. Another important aging mechanism is the metal dissolution from the cathode and the subsequent deposition on the anode. For the anode, the main aging mechanisms are the loss of recyclable lithium ions caused by the formation and increasing growth of a solid electrolyte interphase (SEI and the mechanical fatigue caused by the diffusion-induced stress on the carbon anode particles. Additionally, electrode aging largely depends on the electrochemical behaviour under cycling and storage conditions and results from both structural/morphological changes and side reactions aggravated by decomposition products and protic impurities in the electrolyte.

  18. Aging-associated inflammation promotes selection for adaptive oncogenic events in B cell progenitors.

    Science.gov (United States)

    Henry, Curtis J; Casás-Selves, Matias; Kim, Jihye; Zaberezhnyy, Vadym; Aghili, Leila; Daniel, Ashley E; Jimenez, Linda; Azam, Tania; McNamee, Eoin N; Clambey, Eric T; Klawitter, Jelena; Serkova, Natalie J; Tan, Aik Choon; Dinarello, Charles A; DeGregori, James

    2015-12-01

    The incidence of cancer is higher in the elderly; however, many of the underlying mechanisms for this association remain unexplored. Here, we have shown that B cell progenitors in old mice exhibit marked signaling, gene expression, and metabolic defects. Moreover, B cell progenitors that developed from hematopoietic stem cells (HSCs) transferred from young mice into aged animals exhibited similar fitness defects. We further demonstrated that ectopic expression of the oncogenes BCR-ABL, NRAS(V12), or Myc restored B cell progenitor fitness, leading to selection for oncogenically initiated cells and leukemogenesis specifically in the context of an aged hematopoietic system. Aging was associated with increased inflammation in the BM microenvironment, and induction of inflammation in young mice phenocopied aging-associated B lymphopoiesis. Conversely, a reduction of inflammation in aged mice via transgenic expression of α-1-antitrypsin or IL-37 preserved the function of B cell progenitors and prevented NRAS(V12)-mediated oncogenesis. We conclude that chronic inflammatory microenvironments in old age lead to reductions in the fitness of B cell progenitor populations. This reduced progenitor pool fitness engenders selection for cells harboring oncogenic mutations, in part due to their ability to correct aging-associated functional defects. Thus, modulation of inflammation--a common feature of aging--has the potential to limit aging-associated oncogenesis.

  19. Flatfoot in school-age children: prevalence and associated factors.

    Science.gov (United States)

    Sadeghi-Demneh, Ebrahim; Jafarian, Fahimehsadat; Melvin, Jonathan M A; Azadinia, Fatemeh; Shamsi, Fatemeh; Jafarpishe, Mohamad

    2015-06-01

    Flatfoot has been shown to cause abnormal stresses on the foot and lower extremity. The altered mechanical stresses on these structures can aggravate the foot deformity. Screening of the flatfoot and its associated factors helps detect underlying risks influencing the stresses on the foot. The purpose of this study was to analyze the structure of the medial foot arch and investigate its associated factors in students, aged 7 to 14 years. Multistage cluster sampling was used and each cluster included 2 other random sampling levels. A total of 667 Iranian school children were recruited and their feet were bilaterally evaluated using a static footprint while standing in a fully weightbearing position. The footprint, an observational measurement, and a questionnaire were used for the foot assessment. The prevalence of flatfoot was 17.1% in the population studied. There was no gender difference but the prevalence of flatfoot did decrease with age. The significant differences were observed in the prevalence of flatfoot between normal-weight, overweight, and obese groups (P plantar arch in school-age children is influenced by age and weight. Age and weight were the primary predictive factors of flatfoot. Prognostic, Level IV: Case series. © 2015 The Author(s).

  20. Maternal Age at Delivery Is Associated with an Epigenetic Signature in Both Newborns and Adults.

    Directory of Open Access Journals (Sweden)

    Christina A Markunas

    Full Text Available Offspring of older mothers are at increased risk of adverse birth outcomes, childhood cancers, type 1 diabetes, and neurodevelopmental disorders. The underlying biologic mechanisms for most of these associations remain obscure. One possibility is that maternal aging may produce lasting changes in the epigenetic features of a child's DNA. To test this, we explored the association of mothers' age at pregnancy with methylation in her offspring, using blood samples from 890 Norwegian newborns and measuring DNA methylation at more than 450,000 CpG sites across the genome. We examined replication of a maternal-age finding in an independent group of 1062 Norwegian newborns, and then in 200 US middle-aged women. Older maternal age was significantly associated with reduced methylation at four adjacent CpGs near the 2nd exon of KLHL35 in newborns (p-values ranging from 3x10-6 to 8x10-7. These associations were replicated in the independent set of newborns, and replicated again in women 40 to 60 years after their birth. This study provides the first example of parental age permanently affecting the epigenetic profile of offspring. While the specific functions of the affected gene are unknown, this finding opens the possibility that a mother's age at pregnancy could affect her child's health through epigenetic mechanisms.

  1. High-dimensional analysis of the aging immune system: verification of age-associated differences in immune signaling responses in healthy donors.

    Science.gov (United States)

    Longo, Diane M; Louie, Brent; Ptacek, Jason; Friedland, Greg; Evensen, Erik; Putta, Santosh; Atallah, Michelle; Spellmeyer, David; Wang, Ena; Pos, Zoltan; Marincola, Francesco M; Schaeffer, Andrea; Lukac, Suzanne; Railkar, Radha; Beals, Chan R; Cesano, Alessandra; Carayannopoulos, Leonidas N; Hawtin, Rachael E

    2014-06-21

    Single-cell network profiling (SCNP) is a multiparametric flow cytometry-based approach that simultaneously measures evoked signaling in multiple cell subsets. Previously, using the SCNP approach, age-associated immune signaling responses were identified in a cohort of 60 healthy donors. In the current study, a high-dimensional analysis of intracellular signaling was performed by measuring 24 signaling nodes in 7 distinct immune cell subsets within PBMCs in an independent cohort of 174 healthy donors [144 elderly (>65 yrs); 30 young (25-40 yrs)]. Associations between age and 9 immune signaling responses identified in the previously published 60 donor cohort were confirmed in the current study. Furthermore, within the current study cohort, 48 additional immune signaling responses differed significantly between young and elderly donors. These associations spanned all profiled modulators and immune cell subsets. These results demonstrate that SCNP, a systems-based approach, can capture the complexity of the cellular mechanisms underlying immunological aging. Further, the confirmation of age associations in an independent donor cohort supports the use of SCNP as a tool for identifying reproducible predictive biomarkers in areas such as vaccine response and response to cancer immunotherapies.

  2. Mechanisms Underlying HIV-Associated Noninfectious Lung Disease.

    Science.gov (United States)

    Presti, Rachel M; Flores, Sonia C; Palmer, Brent E; Atkinson, Jeffrey J; Lesko, Catherine R; Lau, Bryan; Fontenot, Andrew P; Roman, Jesse; McDyer, John F; Twigg, Homer L

    2017-11-01

    Pulmonary disease remains a primary source of morbidity and mortality in persons living with HIV (PLWH), although the advent of potent combination antiretroviral therapy has resulted in a shift from predominantly infectious to noninfectious pulmonary complications. PLWH are at high risk for COPD, pulmonary hypertension, and lung cancer even in the era of combination antiretroviral therapy. The underlying mechanisms of this are incompletely understood, but recent research in both human and animal models suggests that oxidative stress, expression of matrix metalloproteinases, and genetic instability may result in lung damage, which predisposes PLWH to these conditions. Some of the factors that drive these processes include tobacco and other substance use, direct HIV infection and expression of specific HIV proteins, inflammation, and shifts in the microbiome toward pathogenic and opportunistic organisms. Further studies are needed to understand the relative importance of these factors to the development of lung disease in PLWH. Copyright © 2017 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

  3. SVA retrotransposon insertion-associated deletion represents a novel mutational mechanism underlying large genomic copy number changes with non-recurrent breakpoints

    Science.gov (United States)

    2014-01-01

    Background Genomic disorders are caused by copy number changes that may exhibit recurrent breakpoints processed by nonallelic homologous recombination. However, region-specific disease-associated copy number changes have also been observed which exhibit non-recurrent breakpoints. The mechanisms underlying these non-recurrent copy number changes have not yet been fully elucidated. Results We analyze large NF1 deletions with non-recurrent breakpoints as a model to investigate the full spectrum of causative mechanisms, and observe that they are mediated by various DNA double strand break repair mechanisms, as well as aberrant replication. Further, two of the 17 NF1 deletions with non-recurrent breakpoints, identified in unrelated patients, occur in association with the concomitant insertion of SINE/variable number of tandem repeats/Alu (SVA) retrotransposons at the deletion breakpoints. The respective breakpoints are refractory to analysis by standard breakpoint-spanning PCRs and are only identified by means of optimized PCR protocols designed to amplify across GC-rich sequences. The SVA elements are integrated within SUZ12P intron 8 in both patients, and were mediated by target-primed reverse transcription of SVA mRNA intermediates derived from retrotranspositionally active source elements. Both SVA insertions occurred during early postzygotic development and are uniquely associated with large deletions of 1 Mb and 867 kb, respectively, at the insertion sites. Conclusions Since active SVA elements are abundant in the human genome and the retrotranspositional activity of many SVA source elements is high, SVA insertion-associated large genomic deletions encompassing many hundreds of kilobases could constitute a novel and as yet under-appreciated mechanism underlying large-scale copy number changes in the human genome. PMID:24958239

  4. ROS, Cell Senescence, and Novel Molecular Mechanisms in Aging and Age-Related Diseases

    Directory of Open Access Journals (Sweden)

    Pierpaola Davalli

    2016-01-01

    Full Text Available The aging process worsens the human body functions at multiple levels, thus causing its gradual decrease to resist stress, damage, and disease. Besides changes in gene expression and metabolic control, the aging rate has been associated with the production of high levels of Reactive Oxygen Species (ROS and/or Reactive Nitrosative Species (RNS. Specific increases of ROS level have been demonstrated as potentially critical for induction and maintenance of cell senescence process. Causal connection between ROS, aging, age-related pathologies, and cell senescence is studied intensely. Senescent cells have been proposed as a target for interventions to delay the aging and its related diseases or to improve the diseases treatment. Therapeutic interventions towards senescent cells might allow restoring the health and curing the diseases that share basal processes, rather than curing each disease in separate and symptomatic way. Here, we review observations on ROS ability of inducing cell senescence through novel mechanisms that underpin aging processes. Particular emphasis is addressed to the novel mechanisms of ROS involvement in epigenetic regulation of cell senescence and aging, with the aim to individuate specific pathways, which might promote healthy lifespan and improve aging.

  5. Girl-child marriage and its association with morbidity and mortality of children under 5 years of age in a nationally-representative sample of Pakistan.

    Science.gov (United States)

    Nasrullah, Muazzam; Zakar, Rubeena; Zakar, Muhammad Zakria; Krämer, Alexander

    2014-03-01

    To determine the relationship between child marriage (before age 18 years) and morbidity and mortality of children under 5 years of age in Pakistan beyond those attributed to social vulnerabilities. Nationally-representative cross-sectional observational survey data from Pakistan Demographic and Health Survey, 2006-2007 was limited to children from the past 5 years, reported by ever-married women aged 15-24 years (n = 2630 births of n = 2138 mothers) to identify differences in infectious diseases in past 2 weeks (diarrhea, acute respiratory infection [ARI], ARI with fever), under 5 years of age and infant mortality, and low birth weight by early (marriage. Associations between child marriage and mortality and morbidity of children under 5 years of age were assessed by calculating adjusted OR using logistic regression models after controlling for maternal and child demographics. Majority (74.5%) of births were from mothers aged Marriage before age 18 years increased the likelihood of recent diarrhea among children born to young mothers (adjusted OR = 1.59; 95% CI: 1.18-2.14). Even though maternal child marriage was associated with infant mortality and mortality of children under 5 years of age in unadjusted models, association was lost in the adjusted models. We did not find a relation between girl-child marriage and low birth weight infants, and ARI. Girl-child marriage increases the likelihood of recent diarrhea among children born to young mothers. Further qualitative and prospective quantitative studies are needed to understand the factors that may drive child morbidity and mortality among those married as children vs adults in Pakistan. Copyright © 2014 Mosby, Inc. All rights reserved.

  6. Association between maternal socioeconomic factors and nutritional outcomes in children under 5 years of age.

    Science.gov (United States)

    Géa-Horta, Tatiane; Felisbino-Mendes, Mariana Santos; Ortiz, Renzo Joel Flores; Velasquez-Melendez, Gustavo

    To estimate the association between maternal socioeconomic factors and the occurrence of nutritional outcomes in children under five years of age in a representative sample of the Brazilian population. This was a cross-sectional study that evaluated data from the latest National Survey of Children and Women's Demographics and Health, carried out in Brazil in 2006-2007. Maternal employment and maternal level of schooling were the main exposures. The following nutritional outcomes in children were considered: height/age 2SD for overweight. Generalized estimating equations (GEE) were utilized as the regression method. After adjustments, it was observed that children whose mothers had low level of schooling had a higher chance of having short stature (OR=3.97, 95% CI, 1.23-12.80) and children whose mothers worked outside the home were more likely to have excess weight (OR=1.57, 95% CI, 1.02-2.42). Maternal employment was not associated with short stature in children (OR=1.09, 95% CI, 0.67-1.77). Maternal level of schooling was associated with short stature in children and maternal employment with overweight, indicating the need to take into account the socioeconomic factors when proposing programs and strategies aimed at health and nutrition improvement of children, considering inter-sectoral interventions. Copyright © 2016 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  7. Association between maternal socioeconomic factors and nutritional outcomes in children under 5 years of age,

    Directory of Open Access Journals (Sweden)

    Tatiane Géa-Horta

    Full Text Available Abstract Objective: To estimate the association between maternal socioeconomic factors and the occurrence of nutritional outcomes in children under five years of age in a representative sample of the Brazilian population. Methods: This was a cross-sectional study that evaluated data from the latest National Survey of Children and Women's Demographics and Health, carried out in Brazil in 2006-2007. Maternal employment and maternal level of schooling were the main exposures. The following nutritional outcomes in children were considered: height/age 2SD for overweight. Generalized estimating equations (GEE were utilized as the regression method. Results: After adjustments, it was observed that children whose mothers had low level of schooling had a higher chance of having short stature (OR = 3.97, 95% CI, 1.23-12.80 and children whose mothers worked outside the home were more likely to have excess weight (OR = 1.57, 95% CI, 1.02-2.42. Maternal employment was not associated with short stature in children (OR = 1.09, 95% CI, 0.67-1.77. Conclusion: Maternal level of schooling was associated with short stature in children and maternal employment with overweight, indicating the need to take into account the socioeconomic factors when proposing programs and strategies aimed at health and nutrition improvement of children, considering inter-sectoral interventions.

  8. Aging-associated dysfunction of Akt/protein kinase B: S-nitrosylation and acetaminophen intervention.

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    Miaozong Wu

    Full Text Available BACKGROUND: Aged skeletal muscle is characterized by an increased incidence of metabolic and functional disorders, which if allowed to proceed unchecked can lead to increased morbidity and mortality. The mechanism(s underlying the development of these disorders in aging skeletal muscle are not well understood. Protein kinase B (Akt/PKB is an important regulator of cellular metabolism and survival, but it is unclear if aged muscle exhibits alterations in Akt function. Here we report a novel dysfunction of Akt in aging muscle, which may relate to S-nitrosylation and can be prevented by acetaminophen intervention. PRINCIPAL FINDINGS: Compared to 6- and 27-month rats, the phosphorylation of Akt (Ser473 and Thr308 was higher in soleus muscles of very aged rats (33-months. Paradoxically, these increases in Akt phosphorylation were associated with diminished mammalian target of rapamycin (mTOR phosphorylation, along with decreased levels of insulin receptor beta (IR-beta, phosphoinositide 3-kinase (PI3K, phosphatase and tensin homolog deleted on chromosome 10 (PTEN and phosphorylation of phosphoinositide-dependent kinase-1 (PDK1 (Ser241. In vitro Akt kinase measurements and ex vivo muscle incubation experiments demonstrated age-related impairments of Akt kinase activity, which were associated with increases in Akt S-nitrosylation and inducible nitric oxide synthase (iNOS. Impairments in Akt function occurred parallel to increases in myocyte apoptosis and decreases in myocyte size and the expression of myosin and actin. These age-related disorders were attenuated by treating aged (27-month animals with acetaminophen (30 mg/kg body weight/day for 6-months. CONCLUSIONS: These data demonstrate that Akt dysfunction and increased S-nitrosylation of Akt may contribute to age-associated disorders in skeletal muscle and that acetaminophen may be efficacious for the treatment of age-related muscle dysfunction.

  9. Dopamine Receptor Genes Modulate Associative Memory in Old Age.

    Science.gov (United States)

    Papenberg, Goran; Becker, Nina; Ferencz, Beata; Naveh-Benjamin, Moshe; Laukka, Erika J; Bäckman, Lars; Brehmer, Yvonne

    2017-02-01

    Previous research shows that associative memory declines more than item memory in aging. Although the underlying mechanisms of this selective impairment remain poorly understood, animal and human data suggest that dopaminergic modulation may be particularly relevant for associative binding. We investigated the influence of dopamine (DA) receptor genes on item and associative memory in a population-based sample of older adults (n = 525, aged 60 years), assessed with a face-scene item associative memory task. The effects of single-nucleotide polymorphisms of DA D1 (DRD1; rs4532), D2 (DRD2/ANKK1/Taq1A; rs1800497), and D3 (DRD3/Ser9Gly; rs6280) receptor genes were examined and combined into a single genetic score. Individuals carrying more beneficial alleles, presumably associated with higher DA receptor efficacy (DRD1 C allele; DRD2 A2 allele; DRD3 T allele), performed better on associative memory than persons with less beneficial genotypes. There were no effects of these genes on item memory or other cognitive measures, such as working memory, executive functioning, fluency, and perceptual speed, indicating a selective association between DA genes and associative memory. By contrast, genetic risk for Alzheimer disease (AD) was associated with worse item and associative memory, indicating adverse effects of APOE ε4 and a genetic risk score for AD (PICALM, BIN1, CLU) on episodic memory in general. Taken together, our results suggest that DA may be particularly important for associative memory, whereas AD-related genetic variations may influence overall episodic memory in older adults without dementia.

  10. Dysregulation of C-X-C motif ligand 10 during aging and association with cognitive performance.

    Science.gov (United States)

    Bradburn, Steven; McPhee, Jamie; Bagley, Liam; Carroll, Michael; Slevin, Mark; Al-Shanti, Nasser; Barnouin, Yoann; Hogrel, Jean-Yves; Pääsuke, Mati; Gapeyeva, Helena; Maier, Andrea; Sipilä, Sarianna; Narici, Marco; Robinson, Andrew; Mann, David; Payton, Antony; Pendleton, Neil; Butler-Browne, Gillian; Murgatroyd, Chris

    2018-03-01

    Chronic low-grade inflammation during aging (inflammaging) is associated with cognitive decline and neurodegeneration; however, the mechanisms underlying inflammaging are unclear. We studied a population (n = 361) of healthy young and old adults from the MyoAge cohort. Peripheral levels of C-X-C motif chemokine ligand 10 (CXCL10) was found to be higher in older adults, compared with young, and negatively associated with working memory performance. This coincided with an age-related reduction in blood DNA methylation at specific CpGs within the CXCL10 gene promoter. In vitro analysis supported the role of DNA methylation in regulating CXCL10 transcription. A polymorphism (rs56061981) that altered methylation at one of these CpG sites further associated with working memory performance in 2 independent aging cohorts. Studying prefrontal cortex samples, we found higher CXCL10 protein levels in those with Alzheimer's disease, compared with aged controls. These findings support the association of peripheral inflammation, as demonstrated by CXCL10, in aging and cognitive decline. We reveal age-related epigenetic and genetic factors which contribute to the dysregulation of CXCL10. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  11. Underlying Mechanisms of Cooperativity, Input Specificity, and Associativity of Long-Term Potentiation Through a Positive Feedback of Local Protein Synthesis

    Directory of Open Access Journals (Sweden)

    Lijie Hao

    2018-05-01

    Full Text Available Long-term potentiation (LTP is a specific form of activity-dependent synaptic plasticity that is a leading mechanism of learning and memory in mammals. The properties of cooperativity, input specificity, and associativity are essential for LTP; however, the underlying mechanisms are unclear. Here, based on experimentally observed phenomena, we introduce a computational model of synaptic plasticity in a pyramidal cell to explore the mechanisms responsible for the cooperativity, input specificity, and associativity of LTP. The model is based on molecular processes involved in synaptic plasticity and integrates gene expression involved in the regulation of neuronal activity. In the model, we introduce a local positive feedback loop of protein synthesis at each synapse, which is essential for bimodal response and synapse specificity. Bifurcation analysis of the local positive feedback loop of brain-derived neurotrophic factor (BDNF signaling illustrates the existence of bistability, which is the basis of LTP induction. The local bifurcation diagram provides guidance for the realization of LTP, and the projection of whole system trajectories onto the two-parameter bifurcation diagram confirms the predictions obtained from bifurcation analysis. Moreover, model analysis shows that pre- and postsynaptic components are required to achieve the three properties of LTP. This study provides insights into the mechanisms underlying the cooperativity, input specificity, and associativity of LTP, and the further construction of neural networks for learning and memory.

  12. Advanced paternal age is associated with impaired neurocognitive outcomes during infancy and childhood.

    Directory of Open Access Journals (Sweden)

    Sukanta Saha

    2009-03-01

    Full Text Available BACKGROUND: Advanced paternal age (APA is associated with an increased risk of neurodevelopmental disorders such as autism and schizophrenia, as well as with dyslexia and reduced intelligence. The aim of this study was to examine the relationship between paternal age and performance on neurocognitive measures during infancy and childhood. METHODS AND FINDINGS: A sample of singleton children (n = 33,437 was drawn from the US Collaborative Perinatal Project. The outcome measures were assessed at 8 mo, 4 y, and 7 y (Bayley scales, Stanford Binet Intelligence Scale, Graham-Ernhart Block Sort Test, Wechsler Intelligence Scale for Children, Wide Range Achievement Test. The main analyses examined the relationship between neurocognitive measures and paternal or maternal age when adjusted for potential confounding factors. Advanced paternal age showed significant associations with poorer scores on all of the neurocognitive measures apart from the Bayley Motor score. The findings were broadly consistent in direction and effect size at all three ages. In contrast, advanced maternal age was generally associated with better scores on these same measures. CONCLUSIONS: The offspring of older fathers show subtle impairments on tests of neurocognitive ability during infancy and childhood. In light of secular trends related to delayed fatherhood, the clinical implications and the mechanisms underlying these findings warrant closer scrutiny.

  13. Identification of ageing-associated naturally occurring peptides in human urine

    Science.gov (United States)

    Nkuipou-Kenfack, Esther; Bhat, Akshay; Klein, Julie; Jankowski, Vera; Mullen, William; Vlahou, Antonia; Dakna, Mohammed; Koeck, Thomas; Schanstra, Joost P.; Zürbig, Petra; Rudolph, Karl L.; Schumacher, Björn; Pich, Andreas; Mischak, Harald

    2015-01-01

    To assess normal and pathological peptidomic changes that may lead to an improved understanding of molecular mechanisms underlying ageing, urinary peptidomes of 1227 healthy and 10333 diseased individuals between 20 and 86 years of age were investigated. The diseases thereby comprised diabetes mellitus, renal and cardiovascular diseases. Using age as a continuous variable, 116 peptides were identified that significantly (p age in the healthy cohort. The same approach was applied to the diseased cohort. Upon comparison of the peptide patterns of the two cohorts 112 common age-correlated peptides were identified. These 112 peptides predominantly originated from collagen, uromodulin and fibrinogen. While most fibrillar and basement membrane collagen fragments showed a decreased age-related excretion, uromodulin, beta-2-microglobulin and fibrinogen fragments showed an increase. Peptide-based in silico protease analysis was performed and 32 proteases, including matrix metalloproteinases and cathepsins, were predicted to be involved in ageing. Identified peptides, predicted proteases and patient information were combined in a systems biology pathway analysis to identify molecular pathways associated with normal and/or pathological ageing. While perturbations in collagen homeostasis, trafficking of toll-like receptors and endosomal pathways were commonly identified, degradation of insulin-like growth factor-binding proteins was uniquely identified in pathological ageing. PMID:26431327

  14. Epidemic spreading model to characterize misfolded proteins propagation in aging and associated neurodegenerative disorders.

    Science.gov (United States)

    Iturria-Medina, Yasser; Sotero, Roberto C; Toussaint, Paule J; Evans, Alan C

    2014-11-01

    Misfolded proteins (MP) are a key component in aging and associated neurodegenerative disorders. For example, misfolded Amyloid-ß (Aß) and tau proteins are two neuropathogenic hallmarks of Alzheimer's disease. Mechanisms underlying intra-brain MP propagation/deposition remain essentially uncharacterized. Here, is introduced an epidemic spreading model (ESM) for MP dynamics that considers propagation-like interactions between MP agents and the brain's clearance response across the structural connectome. The ESM reproduces advanced Aß deposition patterns in the human brain (explaining 46∼56% of the variance in regional Aß loads, in 733 subjects from the ADNI database). Furthermore, this model strongly supports a) the leading role of Aß clearance deficiency and early Aß onset age during Alzheimer's disease progression, b) that effective anatomical distance from Aß outbreak region explains regional Aß arrival time and Aß deposition likelihood, c) the multi-factorial impact of APOE e4 genotype, gender and educational level on lifetime intra-brain Aß propagation, and d) the modulatory impact of Aß propagation history on tau proteins concentrations, supporting the hypothesis of an interrelated pathway between Aß pathophysiology and tauopathy. To our knowledge, the ESM is the first computational model highlighting the direct link between structural brain networks, production/clearance of pathogenic proteins and associated intercellular transfer mechanisms, individual genetic/demographic properties and clinical states in health and disease. In sum, the proposed ESM constitutes a promising framework to clarify intra-brain region to region transference mechanisms associated with aging and neurodegenerative disorders.

  15. Epidemic spreading model to characterize misfolded proteins propagation in aging and associated neurodegenerative disorders.

    Directory of Open Access Journals (Sweden)

    Yasser Iturria-Medina

    2014-11-01

    Full Text Available Misfolded proteins (MP are a key component in aging and associated neurodegenerative disorders. For example, misfolded Amyloid-ß (Aß and tau proteins are two neuropathogenic hallmarks of Alzheimer's disease. Mechanisms underlying intra-brain MP propagation/deposition remain essentially uncharacterized. Here, is introduced an epidemic spreading model (ESM for MP dynamics that considers propagation-like interactions between MP agents and the brain's clearance response across the structural connectome. The ESM reproduces advanced Aß deposition patterns in the human brain (explaining 46∼56% of the variance in regional Aß loads, in 733 subjects from the ADNI database. Furthermore, this model strongly supports a the leading role of Aß clearance deficiency and early Aß onset age during Alzheimer's disease progression, b that effective anatomical distance from Aß outbreak region explains regional Aß arrival time and Aß deposition likelihood, c the multi-factorial impact of APOE e4 genotype, gender and educational level on lifetime intra-brain Aß propagation, and d the modulatory impact of Aß propagation history on tau proteins concentrations, supporting the hypothesis of an interrelated pathway between Aß pathophysiology and tauopathy. To our knowledge, the ESM is the first computational model highlighting the direct link between structural brain networks, production/clearance of pathogenic proteins and associated intercellular transfer mechanisms, individual genetic/demographic properties and clinical states in health and disease. In sum, the proposed ESM constitutes a promising framework to clarify intra-brain region to region transference mechanisms associated with aging and neurodegenerative disorders.

  16. Cortical mechanics and myosin-II abnormalities associated with post-ovulatory aging: implications for functional defects in aged eggs

    Science.gov (United States)

    Mackenzie, Amelia C.L.; Kyle, Diane D.; McGinnis, Lauren A.; Lee, Hyo J.; Aldana, Nathalia; Robinson, Douglas N.; Evans, Janice P.

    2016-01-01

    STUDY HYPOTHESIS Cellular aging of the egg following ovulation, also known as post-ovulatory aging, is associated with aberrant cortical mechanics and actomyosin cytoskeleton functions. STUDY FINDING Post-ovulatory aging is associated with dysfunction of non-muscle myosin-II, and pharmacologically induced myosin-II dysfunction produces some of the same deficiencies observed in aged eggs. WHAT IS KNOWN ALREADY Reproductive success is reduced with delayed fertilization and when copulation or insemination occurs at increased times after ovulation. Post-ovulatory aged eggs have several abnormalities in the plasma membrane and cortex, including reduced egg membrane receptivity to sperm, aberrant sperm-induced cortical remodeling and formation of fertilization cones at the site of sperm entry, and reduced ability to establish a membrane block to prevent polyspermic fertilization. STUDY DESIGN, SAMPLES/MATERIALS, METHODS Ovulated mouse eggs were collected at 21–22 h post-human chorionic gonadotrophin (hCG) (aged eggs) or at 13–14 h post-hCG (young eggs), or young eggs were treated with the myosin light chain kinase (MLCK) inhibitor ML-7, to test the hypothesis that disruption of myosin-II function could mimic some of the effects of post-ovulatory aging. Eggs were subjected to various analyses. Cytoskeletal proteins in eggs and parthenogenesis were assessed using fluorescence microscopy, with further analysis of cytoskeletal proteins in immunoblotting experiments. Cortical tension was measured through micropipette aspiration assays. Egg membrane receptivity to sperm was assessed in in vitro fertilization (IVF) assays. Membrane topography was examined by low-vacuum scanning electron microscopy (SEM). MAIN RESULTS AND THE ROLE OF CHANCE Aged eggs have decreased levels and abnormal localizations of phosphorylated myosin-II regulatory light chain (pMRLC; P = 0.0062). Cortical tension, which is mediated in part by myosin-II, is reduced in aged mouse eggs when compared with

  17. Aging-associated renal disease in mice is fructokinase dependent.

    Science.gov (United States)

    Roncal-Jimenez, Carlos A; Ishimoto, Takuji; Lanaspa, Miguel A; Milagres, Tamara; Hernando, Ana Andres; Jensen, Thomas; Miyazaki, Makoto; Doke, Tomohito; Hayasaki, Takahiro; Nakagawa, Takahiko; Marumaya, Shoichi; Long, David A; Garcia, Gabriela E; Kuwabara, Masanari; Sánchez-Lozada, Laura G; Kang, Duk-Hee; Johnson, Richard J

    2016-10-01

    Aging-associated kidney disease is usually considered a degenerative process associated with aging. Recently, it has been shown that animals can produce fructose endogenously, and that this can be a mechanism for causing kidney damage in diabetic nephropathy and in association with recurrent dehydration. We therefore hypothesized that low-level metabolism of endogenous fructose might play a role in aging-associated kidney disease. Wild-type and fructokinase knockout mice were fed a normal diet for 2 yr that had minimal (renal injury was amplified by provision of high-salt diet for 3 wk, as noted by the presence of glomerular hypertrophy, mesangial matrix expansion, and alpha smooth muscle actin expression, and with segmental thrombi. Fructokinase knockout mice were protected from renal injury both at baseline and after high salt intake (3 wk) compared with wild-type mice. This was associated with higher levels of active (phosphorylated serine 1177) endothelial nitric oxide synthase in their kidneys. These studies suggest that aging-associated renal disease might be due to activation of specific metabolic pathways that could theoretically be targeted therapeutically, and raise the hypothesis that aging-associated renal injury may represent a disease process as opposed to normal age-related degeneration.

  18. Gene–Environment Correlation Underlying the Association Between Parental Negativity and Adolescent Externalizing Problems

    Science.gov (United States)

    Marceau, Kristine; Horwitz, Briana N.; Ganiban, Jody M.; Reiss, David; Narusyte, Jurgita; Spotts, Erica L.; Neiderhiser, Jenae M.

    2014-01-01

    Studies of adolescent or parent-based twins suggest that gene–environment correlation (rGE) is an important mechanism underlying parent–adolescent relationships. However, information on how parents′ and children’s genes and environments influence correlated parent and child behaviors is needed to distinguish types of rGE. The present study used the novel Extended Children of Twins model to distinguish types of rGE underlying associations between negative parenting and adolescent (age 11–22 years) externalizing problems with a Swedish sample of 909 twin parents and their adolescent offspring and a U.S.-based sample of 405 adolescent siblings and their parents. Results suggest that evocative rGE, not passive rGE or direct environmental effects of parenting on adolescent externalizing, explains associations between maternal and paternal negativity and adolescent externalizing problems. PMID:23573986

  19. Factors Associated with Streptococcal Bacteremia in Diarrheal Children under Five Years of Age and Their Outcome in an Urban Hospital in Bangladesh.

    Directory of Open Access Journals (Sweden)

    Abu Sadat Mohammad Sayeem Bin Shahid

    Full Text Available Although Streptococcal bacteremia is common in diarrheal children with high morbidity and mortality, no systematic data are available on Streptococcal bacteremia in diarrheal children. We sought to evaluate the factors associated with Streptococcal bacteremia in diarrheal children under five years of age and their outcome.We used an unmatched case-control design to investigate the associated factors with Streptococcal bacteremia in all the diarrheal children under five years of age through electronic medical record system of Dhaka hospital of International Centre for Diarrhoeal Disease Research, Bangladesh. We had simultaneously used a retrospective cohort design to further evaluate the outcome of our study children. All the enrolled children had their blood culture done between January 2010 and December 2012. Comparison was made among the children with (cases = 26 and without Streptococcal bacteremia (controls = 78. Controls were selected randomly from hospitalized diarrheal children under five years of age.Cases had proportionately higher deaths compared to controls, but it was statistically insignificant (15% vs. 10%, p = 0.49. The cases more often presented with severe dehydration, fever, respiratory distress, severe sepsis, and abnormal mental status compared to the controls (for all p<0.05. In the logistic regression analysis, after adjusting for potential confounders, it has been found that Streptococcal bacteremia in diarrheal children under five years of age was independently associated with nutritional edema (OR: 5.86, 95% CI = 1.28-26.80, hypoxemia (OR: 19.39, 95% CI = 2.14-175.91, fever (OR: 4.44, 95% CI = 1.13-17.42, delayed capillary refill time (OR: 7.00, 95% CI = 1.36-35.93, and respiratory distress (OR: 2.69, 95% CI = 1.02-7.12.The results of our analyses suggest that diarrheal children under five years of age presenting with nutritional edema, hypoxemia, fever, delayed capillary refill time, and respiratory distress may be at

  20. Advanced paternal age and mortality of offspring under 5 years of age

    DEFF Research Database (Denmark)

    Urhoj, S K; Jespersen, Louise Norman; Nissen, Marie

    2014-01-01

    Study question: Do children born to fathers of advanced age have an increased risk of dying before the age of 5 years? Summary answer: Children born to fathers aged 40 years or more have an increased risk of dying in early childhood due to an excess risk of fatal congenital anomalies, malignancies...... and external causes. What is known already: Advanced paternal age has previously been associated with adverse reproductive outcomes and some long term health problems in the offspring. This is possibly due to specific point mutations, a condition known to increase in the sperm with increasing paternal age....... Study design, size, duration: A Danish population-based register study, designed as a prospective cohort study, of 1 575 521 live born children born from 1978 to 2004. The age of the child (in days) was used as the underlying time and the children entered the cohort the day they were born and were...

  1. Mechanical property degradation and microstructural evolution of cast austenitic stainless steels under short-term thermal aging

    Science.gov (United States)

    Lach, Timothy G.; Byun, Thak Sang; Leonard, Keith J.

    2017-12-01

    Mechanical testing and microstructural characterization were performed on short-term thermally aged cast austenitic stainless steels (CASS) to understand the severity and mechanisms of thermal-aging degradation experienced during extended operation of light water reactor (LWR) coolant systems. Four CASS materials-CF3, CF3M, CF8, and CF8M-were thermally aged for 1500 h at 290 °C, 330 °C, 360 °C, and 400 °C. All four alloys experienced insignificant change in strength and ductility properties but a significant reduction in absorbed impact energy. The primary microstructural and compositional changes during thermal aging were spinodal decomposition of the δ-ferrite into α/α‧, precipitation of G-phase in the δ-ferrite, segregation of solute to the austenite/ferrite interphase boundary, and growth of M23C6 carbides on the austenite/ferrite interphase boundary. These changes were shown to be highly dependent on chemical composition, particularly the concentration of C and Mo, and aging temperature. The low C, high Mo CF3M alloys experienced the most spinodal decomposition and G-phase precipitation coinciding the largest reduction in impact properties.

  2. Molecular profiling of aged neural progenitors identifies Dbx2 as a candidate regulator of age-associated neurogenic decline.

    Science.gov (United States)

    Lupo, Giuseppe; Nisi, Paola S; Esteve, Pilar; Paul, Yu-Lee; Novo, Clara Lopes; Sidders, Ben; Khan, Muhammad A; Biagioni, Stefano; Liu, Hai-Kun; Bovolenta, Paola; Cacci, Emanuele; Rugg-Gunn, Peter J

    2018-06-01

    Adult neurogenesis declines with aging due to the depletion and functional impairment of neural stem/progenitor cells (NSPCs). An improved understanding of the underlying mechanisms that drive age-associated neurogenic deficiency could lead to the development of strategies to alleviate cognitive impairment and facilitate neuroregeneration. An essential step towards this aim is to investigate the molecular changes that occur in NSPC aging on a genomewide scale. In this study, we compare the transcriptional, histone methylation and DNA methylation signatures of NSPCs derived from the subventricular zone (SVZ) of young adult (3 months old) and aged (18 months old) mice. Surprisingly, the transcriptional and epigenomic profiles of SVZ-derived NSPCs are largely unchanged in aged cells. Despite the global similarities, we detect robust age-dependent changes at several hundred genes and regulatory elements, thereby identifying putative regulators of neurogenic decline. Within this list, the homeobox gene Dbx2 is upregulated in vitro and in vivo, and its promoter region has altered histone and DNA methylation levels, in aged NSPCs. Using functional in vitro assays, we show that elevated Dbx2 expression in young adult NSPCs promotes age-related phenotypes, including the reduced proliferation of NSPC cultures and the altered transcript levels of age-associated regulators of NSPC proliferation and differentiation. Depleting Dbx2 in aged NSPCs caused the reverse gene expression changes. Taken together, these results provide new insights into the molecular programmes that are affected during mouse NSPC aging, and uncover a new functional role for Dbx2 in promoting age-related neurogenic decline. © 2018 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

  3. Possible Mechanisms Explaining the Association Between Physical Activity and Mental Health. Findings From the 2001 Dutch Health Behaviour in School-Aged Children Survey

    NARCIS (Netherlands)

    Monshouwer, K.; ten Have, M.; van Poppel, M.N.M.; Kemper, H.C.G.; Vollebergh, W.A.M.

    2013-01-01

    More physical activity is associated with fewer mental health problems among adolescents, but the underlying mechanisms are not clear. The aim of this article is to investigate whether the association between physical activity and mental health is mediated by body-weight perception (self-image) or

  4. Age Differences in Selective Memory of Goal-Relevant Stimuli Under Threat.

    Science.gov (United States)

    Durbin, Kelly A; Clewett, David; Huang, Ringo; Mather, Mara

    2018-02-01

    When faced with threat, people often selectively focus on and remember the most pertinent information while simultaneously ignoring any irrelevant information. Filtering distractors under arousal requires inhibitory mechanisms, which take time to recruit and often decline in older age. Despite the adaptive nature of this ability, relatively little research has examined how both threat and time spent preparing these inhibitory mechanisms affect selective memory for goal-relevant information across the life span. In this study, 32 younger and 31 older adults were asked to encode task-relevant scenes, while ignoring transparent task-irrelevant objects superimposed onto them. Threat levels were increased on some trials by threatening participants with monetary deductions if they later forgot scenes that followed threat cues. We also varied the time between threat induction and a to-be-encoded scene (i.e., 2 s, 4 s, 6 s) to determine whether both threat and timing effects on memory selectivity differ by age. We found that age differences in memory selectivity only emerged after participants spent a long time (i.e., 6 s) preparing for selective encoding. Critically, this time-dependent age difference occurred under threatening, but not neutral, conditions. Under threat, longer preparation time led to enhanced memory for task-relevant scenes and greater memory suppression of task-irrelevant objects in younger adults. In contrast, increased preparation time after threat induction had no effect on older adults' scene memory and actually worsened memory suppression of task-irrelevant objects. These findings suggest that increased time to prepare top-down encoding processes benefits younger, but not older, adults' selective memory for goal-relevant information under threat. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  5. Comparative study of modified polypropylene nanocomposites under environment and accelerated ageing conditions

    International Nuclear Information System (INIS)

    Komatsu, Luiz Gustavo Hiroki

    2016-01-01

    The understanding of degradation mechanism action on the polymer nanocomposites in face of weathering (UV light, heat, acid rain, among others), is the key for development of new additives and new applications. In this work the nanocomposite synthesis was carried in molten state, using twin-screw extruder. The polymer matrix was the HMS-PP (high melt polypropylene) synthesized by gamma irradiation and the nanometric inorganic component was the montmorillonite clay. For better compatibilization between the matrix and clay, it were used maleic anhydride as coupling agent. For environment and in oven accelerated aging assays, the dumbbell samples were prepared under hot pressing. The characterization of clay addition effects and aging effects on the nanocomposites, required the use of techniques of Differential Scanning Calorimetry (DSC), Thermogravimetry (TGA), Fourier Transformed Infrared Spectroscopy (FT-IR), Xray Fluorescence (WDXRF), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and mechanical properties. Samples with 0.1; 1; 3; 5; 10 % of clay were tested. The sample with 5% of clay showed better stability on the environmental assay and accelerated aging in oven assay. On the other hand, the sample with higher percent of clay (10%), was more degraded under on environmental aging than under accelerated aging in stove. In this case, became more resistant until 56 days of assay. On the studied concentrations (less than ≤ 3%) of clay, it can be seen an equilibrium between barrier effect and metallic ions action accelerating the degradative process. (author)

  6. Associations among height, body mass index and intelligence from age 11 to age 78 years.

    Science.gov (United States)

    Harris, Mathew A; Brett, Caroline E; Deary, Ian J; Starr, John M

    2016-09-29

    Intelligence is related to both height and body mass index (BMI) at various stages of life. Several studies have demonstrated longitudinal relationships between these measures, but none has established whether height and intelligence, or BMI and intelligence are linked from childhood through to older age. We assessed the relations between these measures over an interval of up to 67 years using data from the 36-Day Sample, an initially-representative sample of Scottish people born in 1936, assessed at age 11 years (N = 6,291) and again at 77-78 years (N = 722). This paper focuses on the 423 participants (6.7 % of the original sample) who provided relevant data in late adulthood. Height and intelligence were significantly positively associated in childhood (β = .23) and late adulthood (β = .21-.29). Longitudinal correlations also showed that childhood intelligence predicted late-adulthood height (β = .20), and childhood height predicted late-adulthood cognitive ability (β = .12-.14). We observed no significant relationship between BMI and intelligence either in childhood or in late adulthood, nor any longitudinal association between the two in this sample. Our results on height and intelligence are the first to demonstrate that their relationship spans almost seven decades, from childhood through to late adulthood, and they call for further investigation into the mechanisms underlying this lifelong association.

  7. Phospholipase A2 – nexus of aging, oxidative stress, neuronal excitability, and functional decline of the aging nervous system? Insights from a snail model system of neuronal aging and age-associated memory impairment

    OpenAIRE

    Hermann, Petra M.; Watson, Shawn N.; Wildering, Willem C.

    2014-01-01

    TThe aging brain can undergo a range of changes varying from subtle structural and physiological changes causing only minor functional decline under healthy normal aging conditions, to severe cognitive or neurological impairment associated with extensive loss of neurons and circuits due to age-associated neurodegenerative disease conditions. Understanding how biological aging processes affect the brain and how they contribute to the onset and progress of age-associated neurodegenerative disea...

  8. AGING MANAGMENT OF REACTOR COOLANT SYSTEM MECHANICAL COMPONENTS FOR LICENSE RENEWAL

    International Nuclear Information System (INIS)

    SUBUDHI, M.; MORANTE, R.; LEE, A.D.

    2002-01-01

    The reactor coolant system (RCS) mechanical components that require an aging management review for license renewal include the primary loop piping and associated connections to other support systems, reactor vessel, reactor vessel internals, pressurizer. steam generators, reactor coolant pumps, and all other inter-connected piping, pipe fittings, valves, and bolting. All major RCS components are located inside the reactor building. Based on the evaluation findings of recently submitted license renewal applications for pressurized water reactors, this paper presents the plant programs and/or activities proposed by the applicants to manage the effects of aging. These programs and/or activities provide reasonable assurance that the intended function(s) of these mechanical components will be maintained for the period of extended operation. The license renewal application includes identification of RCS subcomponents that are within the scope of license renewal and are vulnerable to age-related degradation when exposed to environmental and operational conditions. determination of the effects of aging on their intended safety functions. and implementation of the aging management programs and/or activities including both current and new programs. Industry-wide operating experience, including generic communication by the NRC, is part of the aging management review for the RCS components. In addition, this paper discusses time-limited aging analyses associated with neutron embrittlement of the reactor vessel beltline region and thermal fatigue

  9. Associations of Partner Age Gap at Sexual Debut with Teenage Parenthood and Lifetime Number of Partners.

    Science.gov (United States)

    Masho, Saba W; Chambers, Gregory J; Wallenborn, Jordyn T; Ferrance, Jacquelyn L

    2017-06-01

    Age at sexual debut and age gap between partners at debut are modifiable characteristics that may be related to risky sexual behaviors. Understanding any such relationships is a necessary first step toward strengthening risk interventions. Age at sexual debut and partner age gap were examined for 3,154 female and 2,713 male respondents to the 2011-2013 National Survey of Family Growth who first had intercourse before age 18. Multivariable logistic regression was used to assess associations between these measures and teenage parenthood and reporting a high lifetime number of partners (i.e., a number above the sample median). Females' odds of teenage parenthood were elevated if sexual debut occurred at ages 15-17 and involved a partner age gap of 3-4 years (odds ratio, 1.8) or more (2.0); they were reduced if debut occurred before age 15 and the gap was 3-4 years (0.8). Females' likelihood of reporting a high lifetime number of partners was negatively associated with age gap (0.4-0.7, depending on age at debut and length of age gap). Males' likelihood of reporting a large number of partners was positively associated with age gap if sexual debut was before age 15 and the gap was five or more years (1.7) or if debut was at ages 15-17 and involved a 3-4-year gap (2.0). Identifying the mechanisms underlying these associations could inform program design and implementation. Copyright © 2017 by the Guttmacher Institute.

  10. Damage mechanisms in PBT-GF30 under thermo-mechanical cyclic loading

    International Nuclear Information System (INIS)

    Schaaf, A.; De Monte, M.; Hoffmann, C.; Vormwald, M.; Quaresimin, M.

    2014-01-01

    The scope of this paper is the investigation of damage mechanisms at microscopic scale on a short glass fiber reinforced polybutylene terephthalate (PBT-GF30) under thermo-mechanical cyclic loading. In addition the principal mechanisms are verified through micro mechanical FE models. In order to investigate the fatigue behavior of the material both isothermal strain controlled fatigue (ISCF) tests at three different temperatures and thermo-mechanical fatigue (TMF) tests were conducted on plain and notched specimens, manufactured by injection molding. The goal of the work is to determine the damage mechanisms occurring under TMF conditions and to compare them with the mechanisms occurring under ISCF. For this reason fracture surfaces of TMF and ISCF samples loaded at different temperature levels were analyzed using scanning electron microscopy. Furthermore, specimens that failed under TMF were examined on microsections revealing insight into both crack initiation and crack propagation. The findings of this investigation give valuable information about the main damage mechanisms of PBT-GF30 under TMF loading and serve as basis for the development of a TMF life estimation methodology

  11. Plant-insect interactions under bacterial influence: ecological implications and underlying mechanisms.

    Science.gov (United States)

    Sugio, Akiko; Dubreuil, Géraldine; Giron, David; Simon, Jean-Christophe

    2015-02-01

    Plants and insects have been co-existing for more than 400 million years, leading to intimate and complex relationships. Throughout their own evolutionary history, plants and insects have also established intricate and very diverse relationships with microbial associates. Studies in recent years have revealed plant- or insect-associated microbes to be instrumental in plant-insect interactions, with important implications for plant defences and plant utilization by insects. Microbial communities associated with plants are rich in diversity, and their structure greatly differs between below- and above-ground levels. Microbial communities associated with insect herbivores generally present a lower diversity and can reside in different body parts of their hosts including bacteriocytes, haemolymph, gut, and salivary glands. Acquisition of microbial communities by vertical or horizontal transmission and possible genetic exchanges through lateral transfer could strongly impact on the host insect or plant fitness by conferring adaptations to new habitats. Recent developments in sequencing technologies and molecular tools have dramatically enhanced opportunities to characterize the microbial diversity associated with plants and insects and have unveiled some of the mechanisms by which symbionts modulate plant-insect interactions. Here, we focus on the diversity and ecological consequences of bacterial communities associated with plants and herbivorous insects. We also highlight the known mechanisms by which these microbes interfere with plant-insect interactions. Revealing such mechanisms in model systems under controlled environments but also in more natural ecological settings will help us to understand the evolution of complex multitrophic interactions in which plants, herbivorous insects, and micro-organisms are inserted. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions

  12. Tau and β-Amyloid Are Associated with Medial Temporal Lobe Structure, Function, and Memory Encoding in Normal Aging

    Energy Technology Data Exchange (ETDEWEB)

    Marks, Shawn M. [Univ. of California, Berkeley, CA (United States). Helen Wills Neuroscience Inst.; Lockhart, Samuel N. [Univ. of California, Berkeley, CA (United States). Helen Wills Neuroscience Inst.; Baker, Suzanne L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Molecular Biophysics and Integrated Bioimaging; Jagust, William J. [Univ. of California, Berkeley, CA (United States). Helen Wills Neuroscience Inst.; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Molecular Biophysics and Integrated Bioimaging

    2017-03-22

    Normal aging is associated with a decline in episodic memory and also with aggregation of the β-amyloid (Aβ) and tau proteins and atrophy of medial temporal lobe (MTL) structures crucial to memory formation. Although some evidence suggests that Aβ is associated with aberrant neural activity, the relationships among these two aggregated proteins, neural function, and brain structure are poorly understood. Using in vivo human Aβ and tau imaging, we demonstrate that increased Aβ and tau are both associated with aberrant fMRI activity in the MTL during memory encoding in cognitively normal older adults. This pathological neural activity was in turn associated with worse memory performance and atrophy within the MTL. A mediation analysis revealed that the relationship with regional atrophy was explained by MTL tau. These findings broaden the concept of cognitive aging to include evidence of Alzheimer’s disease-related protein aggregation as an underlying mechanism of age-related memory impairment.

  13. Nuclear plant aging research - an overview (electrical and mechanical components)

    International Nuclear Information System (INIS)

    Vora, J.P.

    1985-01-01

    As the operating nuclear power plants advance in age there must be a conscious national and international effort to understand the influence and safety implications of aging and service wear of components and structures in nuclear power plants and develop measures which are practical and cost effective for timely mitigation of aging degradation that could significantly affect plant safety. The Office of Nuclear Regulatory Research has, therefore, initiated a multi-year, multi-disciplinary program on Nuclear Plant Aging Research (NPAR). The overall goals identified for the program are as follows: 1) to identify and characterize aging and service wear effects associated with electrical and mechanical components, interfaces, and systems whose failure could impair plant safety; 2) to identify and recommend methods of inspection, surveillance and condition monitoring of electrical and mechanical components and systems which will be effective in detecting significant aging effects prior to loss of safety function so that timely maintenance and repair or replacement can be implemented; and, 3) to identify and recommend acceptable maintenance practices which can be undertaken to mitigate the effects of aging and to diminish the rate and extent of degradation caused by aging and service wear. The specific research activities to be implemented to achieve these goals are described

  14. The Inflammatory Transcription Factors NFκB, STAT1 and STAT3 Drive Age-Associated Transcriptional Changes in the Human Kidney

    Science.gov (United States)

    O’Brown, Zach K.; Van Nostrand, Eric L.; Higgins, John P.; Kim, Stuart K.

    2015-01-01

    Human kidney function declines with age, accompanied by stereotyped changes in gene expression and histopathology, but the mechanisms underlying these changes are largely unknown. To identify potential regulators of kidney aging, we compared age-associated transcriptional changes in the human kidney with genome-wide maps of transcription factor occupancy from ChIP-seq datasets in human cells. The strongest candidates were the inflammation-associated transcription factors NFκB, STAT1 and STAT3, the activities of which increase with age in epithelial compartments of the renal cortex. Stimulation of renal tubular epithelial cells with the inflammatory cytokines IL-6 (a STAT3 activator), IFNγ (a STAT1 activator), or TNFα (an NFκB activator) recapitulated age-associated gene expression changes. We show that common DNA variants in RELA and NFKB1, the two genes encoding subunits of the NFκB transcription factor, associate with kidney function and chronic kidney disease in gene association studies, providing the first evidence that genetic variation in NFκB contributes to renal aging phenotypes. Our results suggest that NFκB, STAT1 and STAT3 underlie transcriptional changes and chronic inflammation in the aging human kidney. PMID:26678048

  15. Are incident gallstones associated to sex-dependent changes with age? A cohort study

    DEFF Research Database (Denmark)

    Shabanzadeh, D M; Holmboe, S A; Sørensen, L T

    2017-01-01

    Age and female sex have repeatedly been identified as gallstone determinants but the underlying mechanisms are not clarified. The objectives of this study were to determine if changes with age in physiology, lifestyle, or reproductive hormones were associated with incident gallstones. A cohort...... pressure, blood lipids, self-rated health), lifestyle (smoking, alcohol and coffee consumption, dietary habits, physical activity level), and indices of reproductive function (number of births, oral contraceptive use, hormone replacement therapy, male reproductive hormones) were explored in females...... (OR) 0.94, 95% confidence interval (CI) [0.90; 0.98]) and the cessation of hormone replacement therapy (OR 0.29, 95% CI [0.10; 0.83]) inversely determined incident gallstones. In males, increasing levels of SHBG (OR 0.97, 95% CI [0.94; 0.998]) inversely determined incident gallstones. Other changes...

  16. NUTRITIONAL STATUS AND ASSOCIATED FACTORS IN UNDER-FIVE CHILDREN OF RAWALPINDI.

    Science.gov (United States)

    Mahmood, Shafaq; Nadeem, Sehrish; Saif, Tayyaba; Mannan, Mavra; Arshad, Urooj

    2016-01-01

    Malnutrition is a serious child health issue throughout the developing world. Pakistan has the second highest infant and child mortality rate in South Asia. This study was carried out to assess the nutritional status of children under 5 years of age and to determine the frequency and association of malnutrition with various demographic variables in the study group. A multi-centre, cross sectional study was conducted at the immunization centres of the 3 allied hospitals of Rawalpindi Medical College during March-May 2014. Healthy children of under 5 years of age without confirmed diagnosis of any disease/ailment were included. Guardians of 100 children were interviewed using a structured questionnaire. Demographic variables include age, gender, family size, family income, breastfeeding, maternal education, presence of a family member with special needs and presence of siblings under 5 years in family. Weight (kg) was measured and malnutrition was assessed by weight for age. Malnutrition was found to be present in 32% of children. Adequately nourished children were 68%, while moderately and severely malnourished children were 14% and 18% respectively. Our study indicated malnutrition to be significantly associated with maternal illiteracy (p = 0.01) and presence of a family member with special needs (p = 0.05). No significant association was found between malnutrition and gender, family size, family income, breast feeding and presence of siblings under 5 years of age. There is a need to plan composite interventions to elucidate the factors that place children at greater risk for malnutrition.

  17. Analysis of Strengthening Mechanisms in an Artificially Aged Ultrafine Grain 6061 Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Rezaei

    2017-12-01

    Full Text Available The current study adopted a quantitative approach to investigating the mechanical properties, and their relationship to the microstructural features, of precipitation-strengthened 6061 aluminum alloy processed through accumulative roll bonding (ARB and aging heat treatment.  To serve this purpose, the contributions of different strengthening mechanisms including grain refinement, precipitation, dislocation and solid-solution strengthening to the yield strength of five-cycle ARB samples processed under pre-aged (ARBed and aged (ARBed+Aged conditions were examined and compared. Microstructural characterizations were performed on the samples through the transmission electron microscope (TEM and X-ray diffraction (XRD. Also, the mechanical properties of the samples were investigated through the tensile test. The obtained results showed that an equiaxed ultrafine grain structure with nano-sized precipitates was created in the both ARBed and ARBed+Aged samples. The grain refinement was the predominant strengthening mechanism which was estimated to contribute 151 and 226 MPa to the ARBed and ARBed+Aged samples, respectively, while the dislocation and Orowan strengthening mechanisms were ranked second with regard to their contributions to the ARBed and ARBed+Aged samples, respectively. The overall yield strength, calculated through the root mean square summation method, was found to be in good agreement with the experimentally determined yield strength. It was also found that the presence of non-shearable precipitates, which interfered with the movement of the dislocations, would be effective for the simultaneous improvement of the strength and ductility of the ARBed+Agedsample .

  18. Aging and loading rate effects on the mechanical behavior of equine bone

    Science.gov (United States)

    Kulin, Robb M.; Jiang, Fengchun; Vecchio, Kenneth S.

    2008-06-01

    Whether due to a sporting accident, high-speed impact, fall, or other catastrophic event, the majority of clinical bone fractures occur under dynamic loading conditions. However, although extensive research has been performed on the quasi-static fracture and mechanical behavior of bone to date, few high-quality studies on the fracture behavior of bone at high strain rates have been performed. Therefore, many questions remain regarding the material behavior, including not only the loading-rate-dependent response of bone, but also how this response varies with age. In this study, tests were performed on equine femoral bone taken post-mortem from donors 6 months to 28 years of age. Quasi-static and dynamic tests were performed to determine the fracture toughness and compressive mechanical behavior as a function of age at varying loading rates. Fracture paths were then analyzed using scanning confocal and scanning-electron microscopy techniques to assess the role of various microstructural features on toughening mechanisms.

  19. Effect of thermal ageing on mechanical properties of a high-strength ODS alloy

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Sung Hoon; Kim, Sung Hwan; Jang, Chang Heui [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Kim, Tae Kyu [Nuclear Materials DivisionKorea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    A new high-strength ODS alloy, ARROS, was recently developed for the application as the cladding material of a Sodium-cooled fast reactor (SFR). To assess the long-term integrity under thermal ageing, ARROS was thermally aged in air at 650°C for 1000 h. The degree of thermal ageing was assessed by mechanical tests such as uniaxial tensile, hardness, and small punch tests at from room temperature to 650°C. Tensile strength was slightly decreased but elongation, hardness, and small punch energy were hardly changed at all test temperatures for the specimen aged at 650°C for 1000 h. However, the variation in mechanical properties such as hardness and small punch energy increased after thermal ageing. Using the test results, the correlation between tensile strength and maximum small punch load was established.

  20. Mitochondrial DNA repair and association with aging- an update

    DEFF Research Database (Denmark)

    Diaz, Ricardo Gredilla; Bohr, Vilhelm; Stevnsner, Tinna V.

    2010-01-01

    in the aging process and to be particularly deleterious in post-mitotic cells. Thus, DNA repair is an important mechanism for maintenance of genomic integrity. Despite the importance of mitochondria in the aging process, it was thought for many years that mitochondria lacked an enzymatic DNA repair system...... proteins and novel DNA repair pathways, thought to be exclusively present in the nucleus, have recently been described also to be present in mitochondria. Here we review the main mitochondrial DNA repair pathways and their association with the aging process....

  1. eNOS-uncoupling in age-related erectile dysfunction

    OpenAIRE

    Johnson, JM; Bivalacqua, TJ; Lagoda, GA; Burnett, AL; Musicki, B

    2011-01-01

    Aging is associated with ED. Although age-related ED is attributed largely to increased oxidative stress and endothelial dysfunction in the penis, the molecular mechanisms underlying this effect are not fully defined. We evaluated whether endothelial nitric oxide synthase (eNOS) uncoupling in the aged rat penis is a contributing mechanism. Correlatively, we evaluated the effect of replacement with eNOS cofactor tetrahydrobiopterin (BH4) on erectile function in the aged rats. Male Fischer 344 ...

  2. Association between mammographic density and pregnancies relative to age and BMI: a breast cancer case-only analysis.

    Science.gov (United States)

    Hack, Carolin C; Emons, Julius; Jud, Sebastian M; Heusinger, Katharina; Adler, Werner; Gass, Paul; Haeberle, Lothar; Heindl, Felix; Hein, Alexander; Schulz-Wendtland, Rüdiger; Uder, Michael; Hartmann, Arndt; Beckmann, Matthias W; Fasching, Peter A; Pöhls, Uwe G

    2017-12-01

    Percentage mammographic density (PMD) is a major risk factor for breast cancer (BC). It is strongly associated with body mass index (BMI) and age, which are themselves risk factors for breast cancer. This analysis investigated the association between the number of full-term pregnancies and PMD in different subgroups relative to age and BMI. Patients were identified in the breast cancer database of the University Breast Center for Franconia. A total of 2410 patients were identified, for whom information on parity, age, and BMI, and a mammogram from the time of first diagnosis were available for assessing PMD. Linear regression analyses were conducted to investigate the influence on PMD of the number of full-term pregnancies (FTPs), age, BMI, and interaction terms between them. As in previous studies, age, number of FTPs, and BMI were found to be associated with PMD in the expected direction. However, including the respective interaction terms improved the prediction of PMD even further. Specifically, the association between PMD and the number of FTPs differed in young patients under the age of 45 (mean decrease of 0.37 PMD units per pregnancy) from the association in older age groups (mean decrease between 2.29 and 2.39 PMD units). BMI did not alter the association between PMD and the number of FTPs. The effect of pregnancies on mammographic density does not appear to become apparent before the age of menopause. The mechanism that drives the effect of pregnancies on mammographic density appears to be counter-regulated by other influences on mammographic density in younger patients.

  3. Psychiatric disorders and leukocyte telomere length: Underlying mechanisms linking mental illness with cellular aging.

    Science.gov (United States)

    Lindqvist, Daniel; Epel, Elissa S; Mellon, Synthia H; Penninx, Brenda W; Révész, Dóra; Verhoeven, Josine E; Reus, Victor I; Lin, Jue; Mahan, Laura; Hough, Christina M; Rosser, Rebecca; Bersani, F Saverio; Blackburn, Elizabeth H; Wolkowitz, Owen M

    2015-08-01

    Many psychiatric illnesses are associated with early mortality and with an increased risk of developing physical diseases that are more typically seen in the elderly. Moreover, certain psychiatric illnesses may be associated with accelerated cellular aging, evidenced by shortened leukocyte telomere length (LTL), which could underlie this association. Shortened LTL reflects a cell's mitotic history and cumulative exposure to inflammation and oxidation as well as the availability of telomerase, a telomere-lengthening enzyme. Critically short telomeres can cause cells to undergo senescence, apoptosis or genomic instability, and shorter LTL correlates with poorer health and predicts mortality. Emerging data suggest that LTL may be reduced in certain psychiatric illnesses, perhaps in proportion to exposure to the psychiatric illnesses, although conflicting data exist. Telomerase has been less well characterized in psychiatric illnesses, but a role in depression and in antidepressant and neurotrophic effects has been suggested by preclinical and clinical studies. In this article, studies on LTL and telomerase activity in psychiatric illnesses are critically reviewed, potential mediators are discussed, and future directions are suggested. A deeper understanding of cellular aging in psychiatric illnesses could lead to re-conceptualizing them as systemic illnesses with manifestations inside and outside the brain and could identify new treatment targets. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. The health of Inuit children under age 6 in Canada.

    Science.gov (United States)

    Findlay, Leanne C; Janz, Teresa A

    2012-01-01

    Previous research has suggested that Inuit children experience poor health as compared to their non-Aboriginal counterparts, although social determinants such as family and social conditions, lifestyle or behaviour, and cultural factors may be at play. The purpose of the current study was to examine the parent-reported health of Inuit children under 6 years of age living in Canada. Data from the 2006 Aboriginal Children's Survey were used to examine measures of Inuit child health as rated by parents including child health, limitations to physical activity, chronic conditions, ear infections, and dental problems. Associations between social determinants of health and parent-rated Inuit child health were also explored. Most Inuit children under age 6 were reported by their parents or guardians to be in excellent or very good health. The most common chronic conditions identified were asthma, speech and language difficulties, allergies, lactose intolerance, and hearing impairment. Several social determinants of health were associated with child health, including parental education, household income, breastfeeding, and perceived housing conditions. The findings show that social determinants of health, including both socio-economic and household characteristics, are associated with Inuit child health.

  5. Behaviour and failure of C-Mn steel in presence of ageing under strain

    International Nuclear Information System (INIS)

    Belotteau Schroeder, Jeanne

    2009-01-01

    As carbon-manganese (C-Mn) steels are largely used in various mechanical applications, and more particularly in secondary circuit pipes of pressurized water nuclear reactors (PWR), this research thesis reports the behaviour and failure modelling of such a steel within a large temperature domain (between 20 and 350 deg C). Tensile tests have been performed on smooth samples and on notches axisymmetric samples, and tear tests have been performed on CT samples. The model of Es trin Kubin-McCormick which takes ageing under strain into account has been used to simulate most of the effects of ageing under strain: negative sensitivity of flow stress to strain rate, Luders bands, PLC effect, modification of tensile mechanical properties, so on. The model is applied to the considered samples. In order to predict the failure of notched specimens, a failure local approach has been applied [fr

  6. Development of an advanced PFM code for the integrity evaluation of nuclear piping system under combined aging mechanisms

    International Nuclear Information System (INIS)

    Datta, Debashis

    2010-02-01

    A nuclear piping system is composed of several straight pipes and elbows joined by welding. These weld sections are usually the most susceptible failure parts susceptible to various degradation mechanisms. Whereas a specific location of a reactor piping system might fail by a combination of different aging mechanisms, e.g. fatigue and/or stress corrosion cracking, the majority of the piping probabilistic fracture mechanics (PFM) codes can only consider a single aging mechanism at a time. So, a probabilistic fracture mechanics computer code capable of considering multiple aging mechanisms was developed for an accurate failure analysis of each specific component of a nuclear piping section. The newly proposed crack morphology based probabilistic leak flow rate module is introduced in this code to separately treat fatigue and SCC type cracks. Improved models e.g. stressors models, elbow failure model, SIFs model, local seismic occurrence probability model, performance based crack detection models, etc., are also included in this code. Recent probabilistic fatigue (S-N) and SCC crack initiation (S-T) and subsequent crack growth rate models are coded. An integrated probabilistic risk assessment and probabilistic fracture mechanics methodology is proposed. A complete flow chart regarding the combined aging mechanism model is presented. The combined aging mechanism based module can significantly reduce simulation efforts and time. Two NUREG benchmark problems, e.g. reactor pressure vessel outlet nozzle section and a surge line elbow located just below the pressurizer are reinvestigated by this code. The results showed that, contribution of pre-existing cracks in addition to initiating cracks, can significantly increase the overall failure probability. Inconel weld location of reactor pressure vessel outlet nozzle section showed the weakest point in terms of relative through-wall leak failure probability in the order of about 10 -2 at the 40-year plant life. Considering

  7. Prevalence and Associated Factors of Under Nutrition Among Under-Five Children in Babylon Province, Iraq,2016

    Directory of Open Access Journals (Sweden)

    Ismael Hasan Jawad

    2018-01-01

    Full Text Available Background:Malnutrition  in children  under five years of age  is  high priority  public health problems especially in middle and low income countries including Iraq, it is +associated with high morbidity and mortality among infants and young children Objectives:To identify the prevalence and the correlates of under nutrition (underweight, stunting and wasting among children under 5 years of age living in Babylon province, Iraq. Methodology:A cross-sectional descriptive study was conducted, to collect primary information from  mothers  of1000 children attending  ten   randomly selected primary health care centers (five rural and five urban centers in Babylon province during the period from  January through June 2016 ,a scientific questionnaire, anthropometric measurements   (weight for age, length/height for age and weight for height, were used  to assess the nutritional status of the child . Results: The  study revealed that the prevalence of underweight , stunting and  wasting were 7.6%, , 20.6%, and 6.6% respectively . Significant statistical  associations were found between all types of under nutrition and the following independent variables p<0.05 ; age,( gender  , more common in boys , low level of mother education , types of  breast feeding and family income. Conclusion:The study concluded that chronic malnutrition in the study area is still a  concern that needs timely intervention by governmental and non-governmental organizations. We conclude that improvements in child feeding, and better maternal education are needed to maintain the children's nutritional status.

  8. On aging factors, aging mechanisms and their combinations in the primary circuit of NPPs

    International Nuclear Information System (INIS)

    Varga, T.; Brumovsky, M.

    1993-01-01

    Ageing is the dominating problem of elder nuclear power plant (NPP) components but still can not be neglected even for the newest ones. Ageing may express itself in different ways: irradiated steel parts may become embrittled, chromium alloy steels may decompose, fatigue life may become exhausted so that cracks may be formed and finally, corrosion attack may result in stress corrosion cracking. However, even synthetics and rubber parts may become inelastic, swell, shrink or crack, electric contacts may be oxydised, or isolations may lose their high electric resistance. Therefore, experts in the different components and their materials have collected and published not only plenty of observations, but also a number of more or less systematic approaches. A general picture, however, still seems to be lacking, due to the fact that ageing factors and mechanisms are not defined and used properly, i.e. - ageing factors act because of the service conditions of the components, as well as the characteristics of the materials which provoke ageing mechanisms - ageing mechanisms cause the changing of properties of the materials involved - combinations of single ageing mechanisms, which can be double, triple or multiple, change and accelerate the ageing process - the consequence of ageing mechanisms is the altering of the properties of the material depending on the lifetime. In this paper we shall try to show a systematic approach to a potential ageing analysis concerning the main metallic components of primary circuits of NPP's - connection between ageing factors, ageing mechanisms and their consequences/effects on component behaviour

  9. Nutritional status and associated factors in under five children of rawalpindi

    International Nuclear Information System (INIS)

    Mahmood, S.; Nadeem, S.; Saif, T.; Mannan, M.; Arshad, U.

    2016-01-01

    Background: Malnutrition is a serious child health issue throughout the developing world. Pakistan has the second highest infant and child mortality rate in South Asia. This study was carried out to assess the nutritional status of children under 5 years of age and to determine the frequency and association of malnutrition with various demographic variables in the study group. Methods: A multi-centre, cross sectional study was conducted at the immunization centres of the 3 allied hospitals of Rawalpindi Medical College during March-May 2014. Healthy children of under 5 years of age without confirmed diagnosis of any disease/ailment were included. Guardians of 100 children were interviewed using a structured questionnaire. Demographic variables include age, gender, family size, family income, breast feeding, maternal education, presence of a family member with special needs and presence of siblings under 5 years in family. Weight (kg) was measured and malnutrition was assessed by weight for age. Results: Malnutrition was found to be present in 32 percentage of children. Adequately nourished children were 68 percentage, while moderately and severely malnourished children were 14 percentage and 18 percentage respectively. Our study indicated malnutrition to be significantly associated with maternal illiteracy (p=0.01) and presence of a family member with special needs (p=0.05). No significant association was found between malnutrition and gender, family size, family income, breast feeding and presence of siblings under 5 years of age. Conclusion: There is a need to plan composite interventions to elucidate the factors that place children at greater risk for malnutrition. (author)

  10. Caffeine alleviates the deterioration of Ca2+ release mechanisms and fragmentation of in vitro aged mouse eggs

    Science.gov (United States)

    Zhang, Nan; Wakai, Takuya; Fissore, Rafael. A.

    2011-01-01

    The developmental competence of mammalian eggs is compromised by postovulatory aging. We and others found that in these eggs the intracellular calcium ([Ca2+]i) responses required for egg activation and initiation of development are altered. Nevertheless, the mechanism(s) underlying this defective Ca2+ release is not well known. Here, we investigated if the function of IP3R1, the major Ca2+ release channel at fertilization, was undermined in in vitro aged mouse eggs. We found that in aged eggs IP3R1 displayed reduced function, as many of the changes acquired during maturation that enhance IP3R1 Ca2+ conductivity such as phosphorylation, receptor reorganization and increased Ca2+ store content ([Ca2+]ER) were lost with increasing postovulatory time. IP3R1 fragmentation, possibly associated with the activation of caspase-3, was also observed in these eggs. Many of these changes were prevented when the postovulatory aging of eggs was carried out in the presence of caffeine, which minimized the decline in IP3R1 function and maintained [Ca2+]ER content. Caffeine also maintained mitochondrial membrane potential as measured by JC-1 fluorescence. We therefore conclude that [Ca2+]i responses in aged eggs are undermined by reduced IP3R1 sensitivity, decreased [Ca2+]ER and compromised mitochondrial function, and that addition of caffeine ameliorates most of these aging-associated changes. Understanding the molecular basis of the protective effects of caffeine will be useful in elucidating, and possibly reversing, the signaling pathway(s) compromised by in vitro culture of eggs. PMID:22095868

  11. Acceleration of Age-Associated Methylation Patterns in HIV-1-Infected Adults

    Science.gov (United States)

    Sehl, Mary; Sinsheimer, Janet S.; Hultin, Patricia M.; Hultin, Lance E.; Quach, Austin; Martínez-Maza, Otoniel; Horvath, Steve; Vilain, Eric; Jamieson, Beth D.

    2015-01-01

    Patients with treated HIV-1-infection experience earlier occurrence of aging-associated diseases, raising speculation that HIV-1-infection, or antiretroviral treatment, may accelerate aging. We recently described an age-related co-methylation module comprised of hundreds of CpGs; however, it is unknown whether aging and HIV-1-infection exert negative health effects through similar, or disparate, mechanisms. We investigated whether HIV-1-infection would induce age-associated methylation changes. We evaluated DNA methylation levels at >450,000 CpG sites in peripheral blood mononuclear cells (PBMC) of young (20-35) and older (36-56) adults in two separate groups of participants. Each age group for each data set consisted of 12 HIV-1-infected and 12 age-matched HIV-1-uninfected samples for a total of 96 samples. The effects of age and HIV-1 infection on methylation at each CpG revealed a strong correlation of 0.49, pmodules; module 3 (ME3) was significantly correlated with age (cor=0.70) and HIV-1 status (cor=0.31). Older HIV-1+ individuals had a greater number of hypermethylated CpGs across ME3 (p=0.015). In a multivariate model, ME3 was significantly associated with age and HIV status (Data set 1: βage= 0.007088, p=2.08 x 10-9; βHIV= 0.099574, p=0.0011; Data set 2: βage= 0.008762, p=1.27x 10-5; βHIV= 0.128649, p= 0.0001). Using this model, we estimate that HIV-1 infection accelerates age-related methylation by approximately 13.7 years in data set 1 and 14.7 years in data set 2. The genes related to CpGs in ME3 are enriched for polycomb group target genes known to be involved in cell renewal and aging. The overlap between ME3 and an aging methylation module found in solid tissues is also highly significant (Fisher-exact p=5.6 x 10-6, odds ratio=1.91). These data demonstrate that HIV-1 infection is associated with methylation patterns that are similar to age-associated patterns and suggest that general aging and HIV-1 related aging work through some common cellular

  12. The missing link between sleep disorders and age-related dementia: recent evidence and plausible mechanisms.

    Science.gov (United States)

    Zhang, Feng; Zhong, Rujia; Li, Song; Chang, Raymond Chuen-Chung; Le, Weidong

    2017-05-01

    Sleep disorders are among the most common clinical problems and possess a significant concern for the geriatric population. More importantly, while around 40% of elderly adults have sleep-related complaints, sleep disorders are more frequently associated with co-morbidities including age-related neurodegenerative diseases and mild cognitive impairment. Recently, increasing evidence has indicated that disturbed sleep may not only serve as the consequence of brain atrophy, but also contribute to the pathogenesis of dementia and, therefore, significantly increase dementia risk. Since the current therapeutic interventions lack efficacies to prevent, delay or reverse the pathological progress of dementia, a better understanding of underlying mechanisms by which sleep disorders interact with the pathogenesis of dementia will provide possible targets for the prevention and treatment of dementia. In this review, we briefly describe the physiological roles of sleep in learning/memory, and specifically update the recent research evidence demonstrating the association between sleep disorders and dementia. Plausible mechanisms are further discussed. Moreover, we also evaluate the possibility of sleep therapy as a potential intervention for dementia.

  13. Mechanical Properties and Microstructural Characterization of Aged Nickel-based Alloy 625 Weld Metal

    Science.gov (United States)

    Silva, Cleiton Carvalho; de Albuquerque, Victor Hugo C.; Miná, Emerson Mendonça; Moura, Elineudo P.; Tavares, João Manuel R. S.

    2018-03-01

    The aim of this work was to evaluate the different phases formed during solidification and after thermal aging of the as-welded 625 nickel-based alloy, as well as the influence of microstructural changes on the mechanical properties. The experiments addressed aging temperatures of 650 and 950 °C for 10, 100, and 200 hours. The samples were analyzed by electron microscopy, microanalysis, and X-ray diffraction in order to identify the secondary phases. Mechanical tests such as hardness, microhardness, and Charpy-V impact test were performed. Nondestructive ultrasonic inspection was also conducted to correlate the acquired signals with mechanical and microstructural properties. The results show that the alloy under study experienced microstructural changes when aged at 650 °C. The aging was responsible by the dissolution of the Laves phase formed during the solidification and the appearance of γ″ phase within interdendritic region and fine carbides along the solidification grain boundaries. However, when it was aged at 950 °C, the Laves phase was continuously dissolved and the excess Nb caused the precipitation of the δ-phase (Ni3Nb), which was intensified at 10 hours of aging, with subsequent dissolution for longer periods such as 200 hours. Even when subjected to significant microstructural changes, the mechanical properties, especially toughness, were not sensitive to the dissolution and/or precipitation of the secondary phases.

  14. Age-related memory decline is associated with vascular and microglial degeneration in aged rats.

    Science.gov (United States)

    Zhang, Rong; Kadar, Tamar; Sirimanne, Ernest; MacGibbon, Alastair; Guan, Jian

    2012-12-01

    The hippocampus processes memory is an early target of aging-related biological and structural lesions, leading to memory decline. With absent neurodegeneration in the hippocampus, which identified in rodent model of normal aging the pathology underlying age-related memory impairment is not complete. The effective glial-vascular networks are the key for maintaining neuronal functions. The changes of glial cells and cerebral capillaries with age may contribute to memory decline. Thus we examined age associated changes in neurons, glial phenotypes and microvasculature in the hippocampus of aged rats with memory decline. Young adult (6 months) and aged (35 months) male rats (Fisher/Norway-Brown) were used. To evaluate memory, four days of acquisition phase of Morris water maze tasks were carried out in both age groups and followed by a probe trial 2 h after the acquisition. The brains were then collected for analysis using immunochemistry. The aged rats showed a delayed latency (pvascular and microglial degeneration with reduced vascular endothelial growth factor and elevated GFAP expression in the hippocampus. The data indicate the memory decline with age is associated with neuronal dysfunction, possibly due to impaired glial-vascular-neuronal networks, but not neuronal degeneration. Glial and vascular degeneration found in aged rats may represent early event of aging pathology prior to neuronal degeneration. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Age- and Hypertension-Associated Protein Aggregates in Mouse Heart Have Similar Proteomic Profiles.

    Science.gov (United States)

    Ayyadevara, Srinivas; Mercanti, Federico; Wang, Xianwei; Mackintosh, Samuel G; Tackett, Alan J; Prayaga, Sastry V S; Romeo, Francesco; Shmookler Reis, Robert J; Mehta, Jawahar L

    2016-05-01

    Neurodegenerative diseases are largely defined by protein aggregates in affected tissues. Aggregates contain some shared components as well as proteins thought to be specific for each disease. Aggregation has not previously been reported in the normal, aging heart or the hypertensive heart. Detergent-insoluble protein aggregates were isolated from mouse heart and characterized on 2-dimensional gels. Their levels increased markedly and significantly with aging and after sustained angiotensin II-induced hypertension. Of the aggregate components identified by high-resolution proteomics, half changed in abundance with age (392/787) or with sustained hypertension (459/824), whereas 30% (273/901) changed concordantly in both, each Phypertensive hearts, we posited that aging of fibroblasts may contribute to the aggregates observed in cardiac tissue. Indeed, as cardiac myofibroblasts "senesced" (approached their replicative limit) in vitro, they accrued aggregates with many of the same constituent proteins observed in vivo during natural aging or sustained hypertension. In summary, we have shown for the first time that compact (detergent-insoluble) protein aggregates accumulate during natural aging, chronic hypertension, and in vitro myofibroblast senescence, sharing many common proteins. Thus, aggregates that arise from disparate causes (aging, hypertension, and replicative senescence) may have common underlying mechanisms of accrual. © 2016 American Heart Association, Inc.

  16. Associations Between Family History of Substance Use, Childhood Trauma, and Age of First Drug Use in Persons With Methamphetamine Dependence.

    Science.gov (United States)

    Svingen, Leah; Dykstra, Rita E; Simpson, Jamie L; Jaffe, Anna E; Bevins, Rick A; Carlo, Gustavo; DiLillo, David; Grant, Kathleen M

    2016-01-01

    The current study examined the association among family history of substance use problems, childhood maltreatment, and age of first drug use in a sample of men and women seeking treatment for methamphetamine dependence. Various forms of childhood maltreatment were considered as mediators of the association between family history of substance use problems and age of first drug use. Participants (N = 99, 40% women, mean age 33) who were under treatment for methamphetamine dependence completed a baseline interview that obtained demographic information, past substance use by participants, history of drug/alcohol problems in their family of origin, and age at first use of any drug (excluding alcohol and tobacco). The Early Trauma Inventory Self-Report-Short Form was used to assess child maltreatment experiences before the age of 18. Family history of substance use problems and childhood physical (but not emotional or sexual) trauma significantly predicted age of first drug use. Further, childhood physical trauma mediated the association between family history of substance use problems and age of first drug use. These findings suggest that the experience of childhood physical abuse may be an important mechanism through which family history of substance use is associated with an earlier age of first drug use.

  17. Evaluation of ethanol aged PVDF: diffusion, crystallinity and dynamic mechanical thermal properties

    International Nuclear Information System (INIS)

    Silva, Agmar J.J.; Costa, Marysilvia F.

    2015-01-01

    This work discuss firstly the effect of the ethanol fuel absorption by PVDF at 60°C through mass variation tests. A Fickian character was observed for the ethanol absorption kinetics of the aged PVDF at 60°C. In the second step, the dynamic mechanical thermal properties (E’, E’, E” and tan δ) of the PVDF were evaluated through dynamic mechanical thermal analysis (DMTA). The chemical structure of the materials was analyzed by X-ray diffraction analysis (XRD), and significant changes in the degree of crystallinity were verified after the aging. However, DMTA results showed a reduction in the storage modulus (E') of the aged PVDF, which was associated to diffusion of ethanol and swelling of the PVDF, which generated a prevailing plasticizing effect and led to reduction of its structural stiffness. (author)

  18. Acceleration of age-associated methylation patterns in HIV-1-infected adults.

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    Tammy M Rickabaugh

    Full Text Available Patients with treated HIV-1-infection experience earlier occurrence of aging-associated diseases, raising speculation that HIV-1-infection, or antiretroviral treatment, may accelerate aging. We recently described an age-related co-methylation module comprised of hundreds of CpGs; however, it is unknown whether aging and HIV-1-infection exert negative health effects through similar, or disparate, mechanisms. We investigated whether HIV-1-infection would induce age-associated methylation changes. We evaluated DNA methylation levels at >450,000 CpG sites in peripheral blood mononuclear cells (PBMC of young (20-35 and older (36-56 adults in two separate groups of participants. Each age group for each data set consisted of 12 HIV-1-infected and 12 age-matched HIV-1-uninfected samples for a total of 96 samples. The effects of age and HIV-1 infection on methylation at each CpG revealed a strong correlation of 0.49, p<1 x 10(-200 and 0.47, p<1 x 10(-200. Weighted gene correlation network analysis (WGCNA identified 17 co-methylation modules; module 3 (ME3 was significantly correlated with age (cor=0.70 and HIV-1 status (cor=0.31. Older HIV-1+ individuals had a greater number of hypermethylated CpGs across ME3 (p=0.015. In a multivariate model, ME3 was significantly associated with age and HIV status (Data set 1: βage=0.007088, p=2.08 x 10(-9; βHIV=0.099574, p=0.0011; Data set 2: βage=0.008762, p=1.27 x 10(-5; βHIV=0.128649, p=0.0001. Using this model, we estimate that HIV-1 infection accelerates age-related methylation by approximately 13.7 years in data set 1 and 14.7 years in data set 2. The genes related to CpGs in ME3 are enriched for polycomb group target genes known to be involved in cell renewal and aging. The overlap between ME3 and an aging methylation module found in solid tissues is also highly significant (Fisher-exact p=5.6 x 10(-6, odds ratio=1.91. These data demonstrate that HIV-1 infection is associated with methylation patterns that

  19. Age-related variance in decisions under ambiguity is explained by changes in reasoning, executive functions, and decision-making under risk.

    Science.gov (United States)

    Schiebener, Johannes; Brand, Matthias

    2017-06-01

    Previous literature has explained older individuals' disadvantageous decision-making under ambiguity in the Iowa Gambling Task (IGT) by reduced emotional warning signals preceding decisions. We argue that age-related reductions in IGT performance may also be explained by reductions in certain cognitive abilities (reasoning, executive functions). In 210 participants (18-86 years), we found that the age-related variance on IGT performance occurred only in the last 60 trials. The effect was mediated by cognitive abilities and their relation with decision-making performance under risk with explicit rules (Game of Dice Task). Thus, reductions in cognitive functions in older age may be associated with both a reduced ability to gain explicit insight into the rules of the ambiguous decision situation and with failure to choose the less risky options consequently after the rules have been understood explicitly. Previous literature may have underestimated the relevance of cognitive functions for age-related decline in decision-making performance under ambiguity.

  20. Associations between changes in city and address specific temperature and QT interval--the VA Normative Aging Study.

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    Amar J Mehta

    Full Text Available BACKGROUND: The underlying mechanisms of the association between ambient temperature and cardiovascular morbidity and mortality are not well understood, particularly for daily temperature variability. We evaluated if daily mean temperature and standard deviation of temperature was associated with heart rate-corrected QT interval (QTc duration, a marker of ventricular repolarization in a prospective cohort of older men. METHODS: This longitudinal analysis included 487 older men participating in the VA Normative Aging Study with up to three visits between 2000-2008 (n = 743. We analyzed associations between QTc and moving averages (1-7, 14, 21, and 28 days of the 24-hour mean and standard deviation of temperature as measured from a local weather monitor, and the 24-hour mean temperature estimated from a spatiotemporal prediction model, in time-varying linear mixed-effect regression. Effect modification by season, diabetes, coronary heart disease, obesity, and age was also evaluated. RESULTS: Higher mean temperature as measured from the local monitor, and estimated from the prediction model, was associated with longer QTc at moving averages of 21 and 28 days. Increased 24-hr standard deviation of temperature was associated with longer QTc at moving averages from 4 and up to 28 days; a 1.9°C interquartile range increase in 4-day moving average standard deviation of temperature was associated with a 2.8 msec (95%CI: 0.4, 5.2 longer QTc. Associations between 24-hr standard deviation of temperature and QTc were stronger in colder months, and in participants with diabetes and coronary heart disease. CONCLUSION/SIGNIFICANCE: In this sample of older men, elevated mean temperature was associated with longer QTc, and increased variability of temperature was associated with longer QTc, particularly during colder months and among individuals with diabetes and coronary heart disease. These findings may offer insight of an important underlying mechanism of

  1. Mechanisms underlying UV-induced immune suppression

    International Nuclear Information System (INIS)

    Ullrich, Stephen E.

    2005-01-01

    Skin cancer is the most prevalent form of human neoplasia. Estimates suggest that in excess of one million new cases of skin cancer will be diagnosed this year alone in the United States (www.cancer.org/statistics). Fortunately, because of their highly visible location, skin cancers are more rapidly diagnosed and more easily treated than other types of cancer. Be that as it may, approximately 10,000 Americans a year die from skin cancer. The cost of treating non-melanoma skin cancer is estimated to be in excess of US$ 650 million a year [J.G. Chen, A.B. Fleischer, E.D. Smith, C. Kancler, N.D. Goldman, P.M. Williford, S.R. Feldman, Cost of non-melanoma skin cancer treatment in the United States, Dermatol. Surg. 27 (2001) 1035-1038], and when melanoma is included, the estimated cost of treating skin cancer in the United States is estimated to rise to US$ 2.9 billion annually (www.cancer.org/statistics). Because the morbidity and mortality associated with skin cancer is a major public health problem, it is important to understand the mechanisms underlying skin cancer development. The primary cause of skin cancer is the ultraviolet (UV) radiation found in sunlight. In addition to its carcinogenic potential, UV radiation is also immune suppressive. In fact, data from studies with both experimental animals and biopsy proven skin cancer patients suggest that there is an association between the immune suppressive effects of UV radiation and its carcinogenic potential. The focus of this manuscript will be to review the mechanisms underlying the induction of immune suppression following UV exposure. Particular attention will be directed to the role of soluble mediators in activating immune suppression

  2. Age-modulated association between prefrontal NAA and the BDNF gene.

    Science.gov (United States)

    Salehi, Basira; Preuss, Nora; van der Veen, Jan Willem; Shen, Jun; Neumeister, Alexander; Drevets, Wayne C; Hodgkinson, Colin; Goldman, David; Wendland, Jens R; Singleton, Andrew; Gibbs, Jesse R; Cookson, Mark R; Hasler, Gregor

    2013-07-01

    Brain-derived neurotrophic factor (BDNF) has been implicated in the pathophysiology of psychiatric and neurological disorders and in the mechanisms of antidepressant pharmacotherapy. Psychiatric and neurological conditions have also been associated with reduced brain levels of N-acetyl-aspartate (NAA), which has been used as a putative marker of neural integrity. However, few studies have explored the relationship between BDNF polymorphisms and NAA levels directly. Here, we present data from a single-voxel proton magnetic resonance spectroscopy study of 64 individuals and explore the relationship between BDNF polymorphisms and prefrontal NAA level. Our results indicate an association between a single nucleotide polymorphism (SNP) within BDNF, known as rs1519480, and reduced NAA level (p = 0.023). NAA levels were further predicted by age and Asian ancestry. There was a significant rs1519480 × age interaction on NAA level (p = 0.031). Specifically, the effect of rs1519480 on NAA level became significant at age ⩾34.17 yr. NAA level decreased with advancing age for genotype TT (p = 0.001) but not for genotype CT (p = 0.82) or CC (p = 0.34). Additional in silico analysis of 142 post-mortem brain samples revealed an association between the same SNP and reduced BDNF mRNA expression in the prefrontal cortex. The rs1519480 SNP influences BDNF mRNA expression and has an impact on prefrontal NAA level over time. This genetic mechanism may contribute to inter-individual variation in cognitive performance seen during normal ageing, as well as contributing to the risk for developing psychiatric and neurological conditions.

  3. Pleiotropic Meta-Analyses of Longitudinal Studies Discover Novel Genetic Variants Associated with Age-Related Diseases

    Directory of Open Access Journals (Sweden)

    Liang He

    2016-10-01

    Full Text Available Age-related diseases may result from shared biological mechanisms in intrinsic processes of aging. Genetic effects on age-related diseases are often modulated by environmental factors due to their little contribution to fitness or are mediated through certain endophenotypes. Identification of genetic variants with pleiotropic effects on both common complex diseases and endophenotypes may reveal potential conflicting evolutionary pressures and deliver new insights into shared genetic contribution to healthspan and lifespan. Here, we performed pleiotropic meta-analyses of genetic variants using five NIH-funded datasets by integrating univariate summary statistics for age-related diseases and endophenotypes. We investigated three groups of traits: (1 endophenotypes such as blood glucose, blood pressure, lipids, hematocrit, and body mass index, (2 time-to-event outcomes such as the age-at-onset of diabetes mellitus (DM, cancer, cardiovascular diseases (CVDs and neurodegenerative diseases (NDs, and (3 both combined. In addition to replicating previous findings, we identify seven novel genome-wide significant loci (< 5e-08, out of which five are low-frequency variants. Specifically, from Group 2, we find rs7632505 on 3q21.1 in SEMA5B, rs460976 on 21q22.3 (1 kb from TMPRSS2 and rs12420422 on 11q24.1 predominantly associated with a variety of CVDs, rs4905014 in ITPK1 associated with stroke and heart failure, rs7081476 on 10p12.1 in ANKRD26 associated with multiple diseases including DM, CVDs, and NDs. From Group 3, we find rs8082812 on 18p11.22 and rs1869717 on 4q31.3 associated with both endophenotypes and CVDs. Our follow-up analyses show that rs7632505, rs4905014, and rs8082812 have age-dependent effects on coronary heart disease or stroke. Functional annotation suggests that most of these SNPs are within regulatory regions or DNase clusters and in linkage disequilibrium with expression quantitative trait loci, implying their potential regulatory

  4. Age at fatherhood: heritability and associations with psychiatric disorders.

    Science.gov (United States)

    Frans, E M; Lichtenstein, P; Hultman, C M; Kuja-Halkola, R

    2016-10-01

    Advancing paternal age has been linked to psychiatric disorders. These associations might be caused by the increased number of de novo mutations transmitted to offspring of older men. It has also been suggested that the associations are confounded by a genetic liability for psychiatric disorders in parents. The aim of this study was to indirectly test the confounding hypotheses by examining if there is a genetic component to advancing paternal age and if men with a genetic liability for psychiatric disorders have children at older ages. We examined the genetic component to advancing paternal age by utilizing the twin model in a cohort of male twins (N = 14 679). We also studied ages at childbirth in men with or without schizophrenia, bipolar disorder and/or autism spectrum disorder. Ages were examined in: (1) healthy men, (2) affected men, (3) healthy men with an affected sibling, (4) men with healthy spouses, (5) men with affected spouses, and (6) men with healthy spouses with an affected sibling. The twin analyses showed that late fatherhood is under genetic influence (heritability = 0.33). However, affected men or men with affected spouses did not have children at older ages. The same was found for healthy individuals with affected siblings. Instead, these men were generally having children at younger ages. Although there is a genetic component influencing late fatherhood, our data suggest that the associations are not explained by psychiatric disorders or a genetic liability for psychiatric disorders in the parent.

  5. Factors associated with acute respiratory infection in children under the age of 5 years: evidence from the 2011 Ethiopia Demographic and Health Survey.

    Science.gov (United States)

    Geberetsadik, Achamyelesh; Worku, Alemayehu; Berhane, Yemane

    2015-01-01

    Acute respiratory tract infection (ARI) remains the major cause of child mortality in Sub-Saharan Africa. Various factors are associated with its occurrence and vary by context. However, available large-scale, population-based data are not fully exploited to identify locally relevant risk factors. The objective of this study was to identify factors associated with ARI in children under the age of 5 years in Ethiopia. Further analysis of the 2011 Ethiopia Demographic and Health Survey was carried out involving 11,645 children under the age of 5 years and their mothers. Information relevant to the current study was extracted from the main data set and a working data set was prepared. A complex survey logistic regression analysis was applied. Acute ARI in this study was associated with severe malnutrition. Children who were severely wasted were highly likely to develop ARI (adjusted odds ratio [AOR] 1.7; 95% confidence interval [CI] 1.1-2.5). ARI was less likely to occur in children from families with an educated father and professional mother (AOR 0.4; 95% CI 0.2-0.6 and AOR 0.1; 95% CI 0.01-0.6, respectively). Malnourished children from a lower socioeconomic category are more likely to suffer from ARI. Targeting disadvantaged children for effective interventions can help reduce the burden of morbidity and death due to ARI.

  6. Age-related effects on postural control under multi-task conditions.

    Science.gov (United States)

    Granacher, Urs; Bridenbaugh, Stephanie A; Muehlbauer, Thomas; Wehrle, Anja; Kressig, Reto W

    2011-01-01

    Changes in postural sway and gait patterns due to simultaneously performed cognitive (CI) and/or motor interference (MI) tasks have previously been reported and are associated with an increased risk of falling in older adults. The objectives of this study were to investigate the effects of a CI and/or MI task on static and dynamic postural control in young and elderly subjects, and to find out whether there is an association between measures of static and dynamic postural control while concurrently performing the CI and/or MI task. A total of 36 healthy young (n = 18; age: 22.3 ± 3.0 years; BMI: 21.0 ± 1.6 kg/m(2)) and elderly adults (n = 18; age: 73.5 ± 5.5 years; BMI: 24.2 ± 2.9 kg/m(2)) participated in this study. Static postural control was measured during bipedal stance, and dynamic postural control was obtained while walking on an instrumented walkway. Irrespective of the task condition, i.e. single-task or multiple tasks, elderly participants showed larger center-of-pressure displacements and greater stride-to-stride variability than younger participants. Associations between measures of static and dynamic postural control were found only under the single-task condition in the elderly. Age-related deficits in the postural control system seem to be primarily responsible for the observed results. The weak correlations detected between static and dynamic measures could indicate that fall-risk assessment should incorporate dynamic measures under multi-task conditions, and that skills like erect standing and walking are independent of each other and may have to be trained complementarily. Copyright © 2010 S. Karger AG, Basel.

  7. Molecular mechanisms underlying the close association between soil Burkholderia and fungi

    Science.gov (United States)

    Stopnisek, Nejc; Zühlke, Daniela; Carlier, Aurélien; Barberán, Albert; Fierer, Noah; Becher, Dörte; Riedel, Katharina; Eberl, Leo; Weisskopf, Laure

    2016-01-01

    Bacterial species belonging to the genus Burkholderia have been repeatedly reported to be associated with fungi but the extent and specificity of these associations in soils remain undetermined. To assess whether associations between Burkholderia and fungi are widespread in soils, we performed a co-occurrence analysis in an intercontinental soil sample collection. This revealed that Burkholderia significantly co-occurred with a wide range of fungi. To analyse the molecular basis of the interaction, we selected two model fungi frequently co-occurring with Burkholderia, Alternaria alternata and Fusarium solani, and analysed the proteome changes caused by cultivation with either fungus in the widespread soil inhabitant B. glathei, whose genome we sequenced. Co-cultivation with both fungi led to very similar changes in the B. glathei proteome. Our results indicate that B. glathei significantly benefits from the interaction, which is exemplified by a lower abundance of several starvation factors that were highly expressed in pure culture. However, co-cultivation also gave rise to stress factors, as indicated by the increased expression of multidrug efflux pumps and proteins involved in oxidative stress response. Our data suggest that the ability of Burkholderia to establish a close association with fungi mainly lies in the capacities to utilize fungal-secreted metabolites and to overcome fungal defense mechanisms. This work indicates that beneficial interactions with fungi might contribute to the survival strategy of Burkholderia species in environments with sub-optimal conditions, including acidic soils. PMID:25989372

  8. Molecular mechanisms underlying the close association between soil Burkholderia and fungi.

    Science.gov (United States)

    Stopnisek, Nejc; Zühlke, Daniela; Carlier, Aurélien; Barberán, Albert; Fierer, Noah; Becher, Dörte; Riedel, Katharina; Eberl, Leo; Weisskopf, Laure

    2016-01-01

    Bacterial species belonging to the genus Burkholderia have been repeatedly reported to be associated with fungi but the extent and specificity of these associations in soils remain undetermined. To assess whether associations between Burkholderia and fungi are widespread in soils, we performed a co-occurrence analysis in an intercontinental soil sample collection. This revealed that Burkholderia significantly co-occurred with a wide range of fungi. To analyse the molecular basis of the interaction, we selected two model fungi frequently co-occurring with Burkholderia, Alternaria alternata and Fusarium solani, and analysed the proteome changes caused by cultivation with either fungus in the widespread soil inhabitant B. glathei, whose genome we sequenced. Co-cultivation with both fungi led to very similar changes in the B. glathei proteome. Our results indicate that B. glathei significantly benefits from the interaction, which is exemplified by a lower abundance of several starvation factors that were highly expressed in pure culture. However, co-cultivation also gave rise to stress factors, as indicated by the increased expression of multidrug efflux pumps and proteins involved in oxidative stress response. Our data suggest that the ability of Burkholderia to establish a close association with fungi mainly lies in the capacities to utilize fungal-secreted metabolites and to overcome fungal defense mechanisms. This work indicates that beneficial interactions with fungi might contribute to the survival strategy of Burkholderia species in environments with sub-optimal conditions, including acidic soils.

  9. Ageing is associated with reduction of mechanically-induced activation of Smad2/3P signaling in articular cartilage

    NARCIS (Netherlands)

    Madej, W.M.; Caam, A.P.M. van; Blaney Davidson, E.N.; Hannink, G.J.; Buma, P.; Kraan, P.M. van der

    2016-01-01

    OBJECTIVE: Mechanical signals control key cellular processes in articular cartilage. Previously we have shown that mechanical compression is an important ALK5/Smad2/3P activator in cartilage explants. However, age-related changes in the cartilage are known to affect tissue mechanosensitivity and

  10. Explanation of enhanced mechanical degradation rate for radiation- aged polyolefins as the aging temperature is decreased

    International Nuclear Information System (INIS)

    Gillen, K.T.; Clough, R.L.; Wise, J.; Malone, M.G.

    1994-01-01

    Degradation rates are normally increased by increasing the responsible environmental stresses. We describe results for a semi-crystalline, crosslinked polyolefin material that contradicts this assumption. In particular, under combined radiation plus thermal environments, this material mechanically degrades much faster at room temperature than it does at elevated temperatures. The probable explanation for this phenomenon relates to the importance on mechanical properties of the tie molecules connecting crystalline and amorphous regions. Partial melting and reforming/ reorganization of crystallites occurs throughout the crystalline melting region (at least room temperature up to 126 C), with the rate of such processes increasing with an increase in temperature. At low temperatures, this process is sufficiently slow such that a large percentage of the radiation-damaged tie molecules will still connect the amorphous and crystalline regions at the end of aging, leading to rapid reductions in tensile properties. At higher temperatures, the enhanced annealing rate will lead, during the aging, to the establishment of new, undamaged tie molecules connecting crystalline and amorphous regions. This healing process will reduce the degradation rate. Evidence in support of this model is presented

  11. Sarcopenic obesity or obese sarcopenia: A cross talk between age-associated adipose tissue and skeletal muscle inflammation as a main mechanism of the pathogenesis.

    Science.gov (United States)

    Kalinkovich, Alexander; Livshits, Gregory

    2017-05-01

    Sarcopenia, an age-associated decline in skeletal muscle mass coupled with functional deterioration, may be exacerbated by obesity leading to higher disability, frailty, morbidity and mortality rates. In the combination of sarcopenia and obesity, the state called sarcopenic obesity (SOB), some key age- and obesity-mediated factors and pathways may aggravate sarcopenia. This review will analyze the mechanisms underlying the pathogenesis of SOB. In obese adipose tissue (AT), adipocytes undergo hypertrophy, hyperplasia and activation resulted in accumulation of pro-inflammatory macrophages and other immune cells as well as dysregulated production of various adipokines that together with senescent cells and the immune cell-released cytokines and chemokines create a local pro-inflammatory status. In addition, obese AT is characterized by excessive production and disturbed capacity to store lipids, which accumulate ectopically in skeletal muscle. These intramuscular lipids and their derivatives induce mitochondrial dysfunction characterized by impaired β-oxidation capacity and increased reactive oxygen species formation providing lipotoxic environment and insulin resistance as well as enhanced secretion of some pro-inflammatory myokines capable of inducing muscle dysfunction by auto/paracrine manner. In turn, by endocrine manner, these myokines may exacerbate AT inflammation and also support chronic low grade systemic inflammation (inflammaging), overall establishing a detrimental vicious circle maintaining AT and skeletal muscle inflammation, thus triggering and supporting SOB development. Under these circumstances, we believe that AT inflammation dominates over skeletal muscle inflammation. Thus, in essence, it redirects the vector of processes from "sarcopenia→obesity" to "obesity→sarcopenia". We therefore propose that this condition be defined as "obese sarcopenia", to reflect the direction of the pathological pathway. Copyright © 2016 Elsevier B.V. All rights

  12. Gut microbiome and lipid metabolism : from associations to mechanisms

    NARCIS (Netherlands)

    Wang, Zheng; Koonen, Debby; Hofker, Marten; Fu, Jingyuan

    Purpose of review The gut microbiome has now been convincingly linked to human metabolic health but the underlying causality and mechanisms remain poorly understood. This review focuses on the recent progress in establishing the associations between gut microbiome species and lipid metabolism in

  13. The influence of age and mild cognitive impairment on associative memory performance and underlying brain networks.

    Science.gov (United States)

    Oedekoven, Christiane S H; Jansen, Andreas; Keidel, James L; Kircher, Tilo; Leube, Dirk

    2015-12-01

    Associative memory is essential to everyday activities, such as the binding of faces and corresponding names to form single bits of information. However, this ability often becomes impaired with increasing age. The most important neural substrate of associative memory is the hippocampus, a structure crucially implicated in the pathogenesis of Alzheimer's disease (AD). The main aim of this study was to compare neural correlates of associative memory in healthy aging and mild cognitive impairment (MCI), an at-risk state for AD. We used fMRI to investigate differences in brain activation and connectivity between young controls (n = 20), elderly controls (n = 32) and MCI patients (n = 21) during associative memory retrieval. We observed lower hippocampal activation in MCI patients than control groups during a face-name recognition task, and the magnitude of this decrement was correlated with lower associative memory performance. Further, increased activation in precentral regions in all older adults indicated a stronger involvement of the task positive network (TPN) with age. Finally, functional connectivity analysis revealed a stronger link of hippocampal and striatal components in older adults in comparison to young controls, regardless of memory impairment. In elderly controls, this went hand-in-hand with a stronger activation of striatal areas. Increased TPN activation may be linked to greater reliance on cognitive control in both older groups, while increased functional connectivity between the hippocampus and the striatum may suggest dedifferentiation, especially in elderly controls.

  14. Identification of novel genes associated with renal tertiary lymphoid organ formation in aging mice

    NARCIS (Netherlands)

    Huang, Yuan; Caputo, Christina R.; Noordmans, Gerda A.; Yazdani, Saleh; Monteiro, Luiz Henrique; van den Born, Jaap; van Goor, Harry; Heeringa, Peter; Korstanje, Ron; Hillebrands, Jan-Luuk

    2014-01-01

    A hallmark of aging-related organ deterioration is a dysregulated immune response characterized by pathologic leukocyte infiltration of affected tissues. Mechanisms and genes involved are as yet unknown. To identify genes associated with aging-related renal infiltration, we analyzed kidneys from

  15. Varicella vaccination coverage of children under two years of age in Germany

    Directory of Open Access Journals (Sweden)

    Reuss Annicka M

    2010-08-01

    Full Text Available Abstract Background Since July 2004, routine varicella vaccination is recommended by the German Standing Vaccination Committee in Germany. Health Insurance Funds started to cover vaccination costs at different time points between 2004 and 2006 in the Federal States. Nationwide representative data on vaccination coverage against varicella of children under two years of age are not available. We aimed to determine varicella vaccination coverage in statutory health insured children under two years of age in twelve German Federal States using data from associations of statutory health insurance physicians (ASHIPs, in order to investigate the acceptance of the recommended routine varicella vaccination programme. Methods We analysed data on varicella vaccination from 13 of 17 ASHIPs of the years 2004 to 2007. The study population consisted of all statutory health insured children under two years of age born in 2004 (cohort 2004 or 2005 (cohort 2005 in one of the studied regions. Vaccination coverage was determined by the number of children vaccinated under 2 years of age within the study population. Results Varicella vaccination coverage of children under two years of age with either one dose of the monovalent varicella vaccine or two doses of the measles, mumps, rubella, and varicella vaccine increased from 34% (cohort 2004 to 51% (cohort 2005 in the studied regions (p Conclusions Our study shows increasing varicella vaccination coverage of young children, indicating a growing acceptance of the routine varicella vaccination programme by the parents and physicians. We recommend further monitoring of vaccination coverage using data from ASHIPs to investigate acceptance of the routine vaccination programmes over time.

  16. Lithium Ion Battery Anode Aging Mechanisms

    Science.gov (United States)

    Agubra, Victor; Fergus, Jeffrey

    2013-01-01

    Degradation mechanisms such as lithium plating, growth of the passivated surface film layer on the electrodes and loss of both recyclable lithium ions and electrode material adversely affect the longevity of the lithium ion battery. The anode electrode is very vulnerable to these degradation mechanisms. In this paper, the most common aging mechanisms occurring at the anode during the operation of the lithium battery, as well as some approaches for minimizing the degradation are reviewed. PMID:28809211

  17. Two distinct neural mechanisms underlying indirect reciprocity.

    Science.gov (United States)

    Watanabe, Takamitsu; Takezawa, Masanori; Nakawake, Yo; Kunimatsu, Akira; Yamasue, Hidenori; Nakamura, Mitsuhiro; Miyashita, Yasushi; Masuda, Naoki

    2014-03-18

    Cooperation is a hallmark of human society. Humans often cooperate with strangers even if they will not meet each other again. This so-called indirect reciprocity enables large-scale cooperation among nonkin and can occur based on a reputation mechanism or as a succession of pay-it-forward behavior. Here, we provide the functional and anatomical neural evidence for two distinct mechanisms governing the two types of indirect reciprocity. Cooperation occurring as reputation-based reciprocity specifically recruited the precuneus, a region associated with self-centered cognition. During such cooperative behavior, the precuneus was functionally connected with the caudate, a region linking rewards to behavior. Furthermore, the precuneus of a cooperative subject had a strong resting-state functional connectivity (rsFC) with the caudate and a large gray matter volume. In contrast, pay-it-forward reciprocity recruited the anterior insula (AI), a brain region associated with affective empathy. The AI was functionally connected with the caudate during cooperation occurring as pay-it-forward reciprocity, and its gray matter volume and rsFC with the caudate predicted the tendency of such cooperation. The revealed difference is consistent with the existing results of evolutionary game theory: although reputation-based indirect reciprocity robustly evolves as a self-interested behavior in theory, pay-it-forward indirect reciprocity does not on its own. The present study provides neural mechanisms underlying indirect reciprocity and suggests that pay-it-forward reciprocity may not occur as myopic profit maximization but elicit emotional rewards.

  18. Sex differences underlying orofacial varicella zoster associated pain in rats.

    Science.gov (United States)

    Stinson, Crystal; Deng, Mohong; Yee, Michael B; Bellinger, Larry L; Kinchington, Paul R; Kramer, Phillip R

    2017-05-17

    Most people are initially infected with varicella zoster virus (VZV) at a young age and this infection results in chickenpox. VZV then becomes latent and reactivates later in life resulting in herpes zoster (HZ) or "shingles". Often VZV infects neurons of the trigeminal ganglia to cause ocular problems, orofacial disease and occasionally a chronic pain condition termed post-herpetic neuralgia (PHN). To date, no model has been developed to study orofacial pain related to varicella zoster. Importantly, the incidence of zoster associated pain and PHN is known to be higher in women, although reasons for this sex difference remain unclear. Prior to this work, no animal model was available to study these sex-differences. Our goal was to develop an orofacial animal model for zoster associated pain which could be utilized to study the mechanisms contributing to this sex difference. To develop this model VZV was injected into the whisker pad of rats resulting in IE62 protein expression in the trigeminal ganglia; IE62 is an immediate early gene in the VZV replication program. Similar to PHN patients, rats showed retraction of neurites after VZV infection. Treatment of rats with gabapentin, an agent often used to combat PHN, ameliorated the pain response after whisker pad injection. Aversive behavior was significantly greater for up to 7 weeks in VZV injected rats over control inoculated rats. Sex differences were also seen such that ovariectomized and intact female rats given the lower dose of VZV showed a longer affective response than male rats. The phase of the estrous cycle also affected the aversive response suggesting a role for sex steroids in modulating VZV pain. These results suggest that this rat model can be utilized to study the mechanisms of 1) orofacial zoster associated pain and 2) the sex differences underlying zoster associated pain.

  19. Wnt16 Is Associated with Age-Related Bone Loss and Estrogen Withdrawal in Murine Bone.

    Directory of Open Access Journals (Sweden)

    Henry Todd

    Full Text Available Genome Wide Association Studies suggest that Wnt16 is an important contributor to the mechanisms controlling bone mineral density, cortical thickness, bone strength and ultimately fracture risk. Wnt16 acts on osteoblasts and osteoclasts and, in cortical bone, is predominantly derived from osteoblasts. This led us to hypothesize that low bone mass would be associated with low levels of Wnt16 expression and that Wnt16 expression would be increased by anabolic factors, including mechanical loading. We therefore investigated Wnt16 expression in the context of ageing, mechanical loading and unloading, estrogen deficiency and replacement, and estrogen receptor α (ERα depletion. Quantitative real time PCR showed that Wnt16 mRNA expression was lower in cortical bone and marrow of aged compared to young female mice. Neither increased nor decreased (by disuse mechanical loading altered Wnt16 expression in young female mice, although Wnt16 expression was decreased following ovariectomy. Both 17β-estradiol and the Selective Estrogen Receptor Modulator Tamoxifen increased Wnt16 expression relative to ovariectomy. Wnt16 and ERβ expression were increased in female ERα-/- mice when compared to Wild Type. We also addressed potential effects of gender on Wnt16 expression and while the expression was lower in the cortical bone of aged males as in females, it was higher in male bone marrow of aged mice compared to young. In the kidney, which we used as a non-bone reference tissue, Wnt16 expression was unaffected by age in either males or females. In summary, age, and its associated bone loss, is associated with low levels of Wnt16 expression whereas bone loss associated with disuse has no effect on Wnt16 expression. In the artificially loaded mouse tibia we observed no loading-related up-regulation of Wnt16 expression but provide evidence that its expression is influenced by estrogen receptor signaling. These findings suggest that while Wnt16 is not an

  20. Mechanisms of aging and fatigue in ferroelectrics

    Energy Technology Data Exchange (ETDEWEB)

    Genenko, Yuri A. [Sonderforschungsbereich 595, Institut für Materialwissenschaft, Technische Universität Darmstadt, Alarich-Weiss-Str. 2, 64287 Darmstadt (Germany); Glaum, Julia [Department of Materials Science and Engineering, University of New South Wales, Sydney (Australia); Hoffmann, Michael J. [Institut für keramische Werkstoffe, Haid-und-Neu Str. 7, Karlsruhe Institute of Technology, 76131 Karlsruhe (Germany); Albe, Karsten, E-mail: albe@mm.tu-darmstadt.de [Sonderforschungsbereich 595, Institut für Materialwissenschaft, Technische Universität Darmstadt, Alarich-Weiss-Str. 2, 64287 Darmstadt (Germany)

    2015-02-15

    Highlights: • Experiments on aging and fatigue of bulk ferroelectrics are thoroughly reviewed. • Lead-based PZT and lead-free BNT–BT and KNN materials are covered. • Various fatigue regimes and factors are classified. • Defect associate formation and alignment are analyzed by density functional theory. • Emerging of internal bias field is studied within drift-diffusion approach. - Abstract: A comprehensive review of aging and fatigue phenomena in bulk polycrystalline ferroelectrics is presented. Three material classes are covered, namely the most widely used Pb[Zr{sub 1−x}Ti{sub x}]O{sub 3} (PZT) ceramics and lead-free materials, including those based on bismuth sodium titanate Bi{sub 1/2}Na{sub 1/2}TiO{sub 3} (BNT) and alkali niobate [K{sub x}Na{sub 1−x}]NbO{sub 3} (KNN). Aging is studied in poled and unpoled states both experimentally and theoretically. The variety of different loading regimes for fatigue includes DC electric field, unipolar, sesquipolar and bipolar cycling and all these differently combined with mechanical loading at different frequencies and temperatures. The role of device geometries and electrode materials is addressed and models describing charge migration and defect dipole re-orientation are discussed in the context of recent experimental studies.

  1. Mechanisms of aging and fatigue in ferroelectrics

    International Nuclear Information System (INIS)

    Genenko, Yuri A.; Glaum, Julia; Hoffmann, Michael J.; Albe, Karsten

    2015-01-01

    Highlights: • Experiments on aging and fatigue of bulk ferroelectrics are thoroughly reviewed. • Lead-based PZT and lead-free BNT–BT and KNN materials are covered. • Various fatigue regimes and factors are classified. • Defect associate formation and alignment are analyzed by density functional theory. • Emerging of internal bias field is studied within drift-diffusion approach. - Abstract: A comprehensive review of aging and fatigue phenomena in bulk polycrystalline ferroelectrics is presented. Three material classes are covered, namely the most widely used Pb[Zr 1−x Ti x ]O 3 (PZT) ceramics and lead-free materials, including those based on bismuth sodium titanate Bi 1/2 Na 1/2 TiO 3 (BNT) and alkali niobate [K x Na 1−x ]NbO 3 (KNN). Aging is studied in poled and unpoled states both experimentally and theoretically. The variety of different loading regimes for fatigue includes DC electric field, unipolar, sesquipolar and bipolar cycling and all these differently combined with mechanical loading at different frequencies and temperatures. The role of device geometries and electrode materials is addressed and models describing charge migration and defect dipole re-orientation are discussed in the context of recent experimental studies

  2. Cellular Mechanisms of Somatic Stem Cell Aging

    Science.gov (United States)

    Jung, Yunjoon

    2014-01-01

    Tissue homeostasis and regenerative capacity rely on rare populations of somatic stem cells endowed with the potential to self-renew and differentiate. During aging, many tissues show a decline in regenerative potential coupled with a loss of stem cell function. Cells including somatic stem cells have evolved a series of checks and balances to sense and repair cellular damage to maximize tissue function. However, during aging the mechanisms that protect normal cell function begin to fail. In this review, we will discuss how common cellular mechanisms that maintain tissue fidelity and organismal lifespan impact somatic stem cell function. We will highlight context-dependent changes and commonalities that define aging, by focusing on three age-sensitive stem cell compartments: blood, neural, and muscle. Understanding the interaction between extrinsic regulators and intrinsic effectors that operate within different stem cell compartments is likely to have important implications for identifying strategies to improve health span and treat age-related degenerative diseases. PMID:24439814

  3. Research advance on stable mechanism of endophytic fungi to red wine colour during the aging

    Science.gov (United States)

    Nan, Lijun; Li, Yashan; Cui, Changwei; Ning, Na; Huang, Jing; Xu, Chengdong; Tao, Fang; Zhang, Jinyong

    2018-04-01

    Based on the fact that persistent mutation of vinous color was not conducive to the stabilization of vinous quality during the aging, research advance on the stable mechanism of endophytic fungi to colour of red wine during the aging, including investigative status and developmental dynamic at home and abroad, endophytes and pigment of materials in wine, including effect of endophyte on vinaceous color, and even the application of tracer method in wine was summarized, respectively. The relationship between diversity of community the endophytic fungi and the main pigment material in wine was existent objectively, also included the response mechanism on colony dynamic of endophytic fungi to the various pigment as well as substance related to color, which laid the foundation for exploring the relationships between endophytic fungi and wine color, and the variational mechanism of the color under endophytic fungi during the aging period of wine. Color as an important reference index of wine quality influenced not only the sensory evaluation of consumer, but also the quality of wine because of the self-aggregation or combination of phenolic composition with other substances under the endophytic fungi during the storage. Only steady wine in the color could guarantee the security of quality.

  4. Underlying mechanisms and the evolving influence of diet

    DEFF Research Database (Denmark)

    Larsen, Lesli Hingstrup

    2012-01-01

    Obesity is determined by both genetic and environmental factors. Since 2007, 52 genes have been associated with obesity and obesity-related measurements in genome-wide association studies (GWAS), among these the fat and obesity-associated gene (FTO). Despite the success in identifying genes predi...... and the microbiome that can be modified by diet, and by genotype, adding to the complexity of determining the contributors to obesity....... has been shown to attenuate the effect of FTO on obesity. Several studies have examined gene-diet interactions in relation to obesity, but only a few suggestive interactions have been identified. This is most probably due to small effect sizes of the interactions and thereby a demand for large samples...... to increased risk of developing obesity. Recently, the intestinal microbiome, the collected genome of the bacteria, also has been associated with obesity and with specific dietary profiles. The underlying mechanisms determining the susceptibility to obesity do not only include the genome but also the epigenome...

  5. Early Age Fracture Mechanics and Cracking of Concrete

    DEFF Research Database (Denmark)

    Østergaard, Lennart

    2003-01-01

    . The reasons are the increased autogenous deformation, the high rate of heat evolution and a higher brittleness of these concretes. Due to these adverse mechanisms the interest in the full description of the behavior of early age concrete has increased dramatically in the last two or three decades. Almost all...... the fictitious crack model and the aim has been experimentally to determine the fracture mechanical properties related to this model. The results provide interesting and important insight into the development of the fracture properties in early age. It is found that the characteristic length has moments of low...... values in early age, which means that the cracking sensibility is higher at those time points. The possible influence of time-dependent effects in the fracture mechanical properties on the cracking behavior in early age has also been investigated. The reason for this has been the known fact...

  6. Comparative Assessment of Stabilised Polybutadiene Binder under Accelerated Ageing

    Directory of Open Access Journals (Sweden)

    Luiz Felipe Cannaval Sbegue

    2016-04-01

    Full Text Available Polybutadiene elastomers are versatile materials, being employed at several applications from rocket propellant binder to adhesives and sealants. The elastomers derived from hydroxyl-terminated polybutadiene are usually stabilised with antioxidants to prevent degradation. In this study, a comparative assessment among 2,2’-methylene-bis (4-methyl-6-tert-butylphenol (AO2246, 2,6-di-tert-butyl-4-methylphenol (BHT, p-phenylenediamine (pPDA, and triphenylphosphine (TPP regarding stabilisation of hydroxyl-terminated polybutadiene binder under accelerated ageing (six months at 65 °C was carried out. Evaluation of antioxidants effectiveness was examined through Oxidation Induction time, sol/gel extraction, swelling and mechanical testing, dynamic mechanical analysis, and mass variation measurement. AO2246 yielded the best performance, meanwhile BHT was poorly protective. TPP acted as prooxidant, causing a severe degradation of the binder, and pPDA was not manageable to be assessed due to the lower curing degree of the resulted polyurethane.

  7. Own-race and own-age biases facilitate visual awareness of faces under interocular suppression

    Directory of Open Access Journals (Sweden)

    Timo eStein

    2014-08-01

    Full Text Available The detection of a face in a visual scene is the first stage in the face processing hierarchy. Although all subsequent, more elaborate face processing depends on the initial detection of a face, surprisingly little is known about the perceptual mechanisms underlying face detection. Recent evidence suggests that relatively hard-wired face detection mechanisms are broadly tuned to all face-like visual patterns as long as they respect the typical spatial configuration of the eyes above the mouth. Here, we qualify this notion by showing that face detection mechanisms are also sensitive to face shape and facial surface reflectance properties. We used continuous flash suppression (CFS to render faces invisible at the beginning of a trial and measured the time upright and inverted faces needed to break into awareness. Young Caucasian adult observers were presented with faces from their own race or from another race (race experiment and with faces from their own age group or from another age group (age experiment. Faces matching the observers’ own race and age group were detected more quickly. Moreover, the advantage of upright over inverted faces in overcoming CFS, i.e. the face inversion effect, was larger for own-race and own-age faces. These results demonstrate that differences in face shape and surface reflectance influence access to awareness and configural face processing at the initial detection stage. Although we did not collect data from observers of another race or age group, these findings are a first indication that face detection mechanisms are shaped by visual experience with faces from one’s own social group. Such experience-based fine-tuning of face detection mechanisms may equip in-group faces with a competitive advantage for access to conscious awareness.

  8. Genome and Epigenome Editing in Mechanistic Studies of Human Aging and Aging-Related Disease.

    Science.gov (United States)

    Lau, Cia-Hin; Suh, Yousin

    2017-01-01

    The recent advent of genome and epigenome editing technologies has provided a new paradigm in which the landscape of the human genome and epigenome can be precisely manipulated in their native context. Genome and epigenome editing technologies can be applied to many aspects of aging research and offer the potential to develop novel therapeutics against age-related diseases. Here, we discuss the latest technological advances in the CRISPR-based genome and epigenome editing toolbox, and provide insight into how these synthetic biology tools could facilitate aging research by establishing in vitro cell and in vivo animal models to dissect genetic and epigenetic mechanisms underlying aging and age-related diseases. We discuss recent developments in the field with the aims to precisely modulate gene expression and dynamic epigenetic landscapes in a spatial and temporal manner in cellular and animal models, by complementing the CRISPR-based editing capability with conditional genetic manipulation tools including chemically inducible expression systems, optogenetics, logic gate genetic circuits, tissue-specific promoters, and the serotype-specific adeno-associated virus. We also discuss how the combined use of genome and epigenome editing tools permits investigators to uncover novel molecular pathways involved in the pathophysiology and etiology conferred by risk variants associated with aging and aging-related disease. A better understanding of the genetic and epigenetic regulatory mechanisms underlying human aging and age-related disease will significantly contribute to the developments of new therapeutic interventions for extending health span and life span, ultimately improving the quality of life in the elderly populations. © 2016 S. Karger AG, Basel.

  9. Socioeconomic factors associated with outcome after cardiac arrest in patients under the age of 65.

    Science.gov (United States)

    Uray, Thomas; Mayr, Florian B; Fitzgibbon, James; Rittenberger, Jon C; Callaway, Clifton W; Drabek, Tomas; Fabio, Anthony; Angus, Derek C; Kochanek, Patrick M; Dezfulian, Cameron

    2015-08-01

    In a prior study of seven North American cities Pittsburgh had the highest crude rate of cardiac arrest deaths in patients 18 to 64 years of age, particularly in neighborhoods with lower socioeconomic status (SES). We hypothesized that lower SES, associated poor health behaviors (e.g., illicit drug use) and pre-existing comorbid conditions (grouped as socioeconomic factors [SE factors]) could affect the type and severity of cardiac arrest, thus outcomes. We retrospectively identified patients aged 18 to 64 years treated for in-hospital (IHCA) and out-of hospital arrest (OHCA) at two Pittsburgh hospitals between January 2010 and July 2012. We abstracted data on baseline demographics and arrest characteristics like place of residence, insurance and employment status. Favorable cerebral performance category [CPC] (1 or 2) was our primary outcome. We examined the associations between SE factors, cardiac arrest variables and outcome as well as post-resuscitation care. Among 415 subjects who met inclusion criteria, unfavorable CPC were more common in patients who were unemployed, had a history of drug abuse or hypertension. In OHCA, favorable CPC was more often associated with presentation with ventricular fibrillation/tachycardia (OR 3.53, 95% CI 1.43-8.74, p = 0.006) and less often associated with non-cardiovascular arrest etiology (OR 0.22, 95% CI 0.08-0.62, p = 0.004). We found strong associations between specific SE factors and arrest factors associated with outcome in OHCA patients only. Significant differences in post-resuscitation care existed based on injury severity, not on SES. SE factors strongly influence type and severity of OHCA but not IHCA resulting in an association with outcomes. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  10. Constitutive modelling of creep-ageing behaviour of peak-aged aluminium alloy 7050

    Directory of Open Access Journals (Sweden)

    Yang Yo-Lun

    2015-01-01

    Full Text Available The creep-ageing behaviour of a peak-aged aluminium alloy 7050 was investigated under different stress levels at 174 ∘C for up to 8 h. Interrupted creep tests and tensile tests were performed to investigate the influences of creep-ageing time and applied stress on yield strength. The mechanical testing results indicate that the material exhibits an over-ageing behaviour which increases with the applied stress level during creep-ageing. As creep-ageing time approaches 8 h, the material's yield strength under different stress levels gradually converge, which suggests that the difference in mechanical properties under different stress conditions can be minimised. This feature can be advantageous in creep-age forming to the formed components such that uniformed mechanical properties across part area can be achieved. A set of constitutive equations was calibrated using the mechanical test results and the alloy-specific material constants were obtained. A good agreement is observed between the experimental and calibrated results.

  11. [Linear growth retardation in children under five years of age: a baseline study].

    Science.gov (United States)

    Rissin, Anete; Figueiroa, José Natal; Benício, Maria Helena D'Aquino; Batista Filho, Malaquias

    2011-10-01

    The scope of this study was to describe the prevalence of, and analyze factors associated with, linear growth retardation in children. The baseline study analyzed 2040 children under the age of five, establishing a possible association between growth delay (height/age index non-binary variables, there was a positive association with roof type and number of inhabitants per room and a negative association with income per capita, mother's schooling and birth weight. The adjusted analysis also indicated water supply, visit from the community health agent, birth delivery location, internment for diarrhea, or for pneumonia and birth weight as significant variables. Several risk factors were identified for linear growth retardation pointing to the multi-causal aspects of the problem and highlighting the need for control measures by the various hierarchical government agents.

  12. Sex, lies and disclosures: Researchers and the reporting of under-age sex

    Directory of Open Access Journals (Sweden)

    Ann Strode

    2009-07-01

    Full Text Available Children are a vulnerable group and require legal protection due to their youth and inexperience. Resultantly, various provisions in the law ensure the care and protection of children through mechanisms such as the mandatory reporting of abuse. A recent change in the law has broadened the mandatory reporting obligations by requiring any person who is aware of a sexual offence having been committed against a child to report this to the police. Given that it is a sexual offence to have sex below the age of 16 researchers involved in research with teenagers in which they may become aware that that they are engaging in sex or sexual activity but are under the age4 of 16 will be obliged to inform the police of this fact. The issue of reporting under-age sex is very complex as in our view there are various categories of under-age sex. We argue that researchers should not comply with the mandatory reporting obligations for underage consensual, non-exploitative sexual activity but in all other cases there should be reporting. We argue that because the mandatory reporting of underage sex/ activity (even consensual and non-exploitative activity may alienate children from services and “punish” them by reporting their conduct to the police, advocacy is needed for a change to the Sexual Offences Act to ensure consistency with the approach taken in the Children’s Act which enables such children to access sexual and reproductive services..

  13. Mechanisms and Kinetics of Organic Aging in High-Level Nuclear Wastes

    International Nuclear Information System (INIS)

    Camaioni, Donald M.; Autrey, S. Thomas; Linehan, John L.

    1999-01-01

    The goal of this project is to develop a fundamental understanding of organic aging and to assemble a model that describes and predicts the thermal and radiolytic aging of organic compounds in high-level wastes (HLW). To reach this goal, we will measure kinetics and elucidate products and mechanisms of organic reactions occurring under conditions of waste storage, retrieval, and processing. Initial emphasis will be placed on studying thermal effects, because organic reaction mechanisms and effects of varying conditions are uncertain, and because we benefit from collaborations with earlier Environmental Management Science Program (EMSP) projects that have worked on radiation effects. Organic complexants are of greatest concern regarding both safety and pretreatment because they have been found to degrade to gases, combust in dry wastes, and interfere with radionuclide separations. Therefore, efforts will focus on studying the reactions of these organic chemicals and associated degradation products. In preliminary work, the authors have used mechanistic kinetic modeling techniques to successfully model the radiolytic degradation of formate to carbonate in HLW simulants. The research will continue development of the model using an iterative process that measures degradation products and kinetics of increasingly complex molecules while adapting the model to reproduce the results each step of the way. Several mechanistic probe experiments have been designed to learn the fundamental mechanisms that operate during thermal degradations so that thermal and radiolytic processes may be integrated within the model. Key kinetic data and thermodynamic properties relating to thermal reactivity will also be acquired so that rate-controlling and product-forming reactions can be predicted. Thermochemical properties of key intermediates will be experimentally and/or theoretically determined to facilitate mechanism verification, structure/reactivity correlation, and prediction of

  14. Quantitative trait loci associated with longevity of lettuce seeds under conventional and controlled deterioration storage conditions.

    Science.gov (United States)

    Schwember, Andrés R; Bradford, Kent J

    2010-10-01

    Lettuce (Lactuca sativa L.) seeds have poor shelf life and exhibit thermoinhibition (fail to germinate) above ∼25°C. Seed priming (controlled hydration followed by drying) alleviates thermoinhibition by increasing the maximum germination temperature, but reduces lettuce seed longevity. Controlled deterioration (CD) or accelerated ageing storage conditions (i.e. elevated temperature and relative humidity) are used to study seed longevity and to predict potential seed lifetimes under conventional storage conditions. Seeds produced in 2002 and 2006 of a recombinant inbred line (RIL) population derived from a cross between L. sativa cv. Salinas×L. serriola accession UC96US23 were utilized to identify quantitative trait loci (QTLs) associated with seed longevity under CD and conventional storage conditions. Multiple longevity-associated QTLs were identified under both conventional and CD storage conditions for control (non-primed) and primed seeds. However, seed longevity was poorly correlated between the two storage conditions, suggesting that deterioration processes under CD conditions are not predictive of ageing in conventional storage conditions. Additionally, the same QTLs were not identified when RIL populations were grown in different years, indicating that lettuce seed longevity is strongly affected by production environment. Nonetheless, a major QTL on chromosome 4 [Seed longevity 4.1 (Slg4.1)] was responsible for almost 23% of the phenotypic variation in viability of the conventionally stored control seeds of the 2006 RIL population, with improved longevity conferred by the Salinas allele. QTL analyses may enable identification of mechanisms responsible for the sensitivity of primed seeds to CD conditions and breeding for improved seed longevity.

  15. Slimmer women's waist is associated with better erectile function in men independent of age.

    Science.gov (United States)

    Brody, Stuart; Weiss, Petr

    2013-10-01

    Previous research has indicated that men generally rate slimmer women as more sexually attractive, consistent with the increased morbidity risks associated with even mild abdominal adiposity. To assess the association of women's waist size with a more tangible measure of perceived sexual attractiveness (as well as reward value for both sexes), we examined the association of women's age and waist circumference with an index of men's erectile function (IIEF-5 scores), frequency of penile-vaginal intercourse (PVI), and sexual satisfaction in a representative sample of Czechs (699 men and 715 women) aged 35-65 years. Multivariate analyses indicated that better erectile function scores were independently associated with younger age of self and partner and women's slimmer waist. PVI frequency was independently associated with women's younger age and women's slimmer waist. Sexual satisfaction was independently associated with men's younger age and slimmer waist for both sexes. Better erectile function, greater PVI frequency, and greater sexual satisfaction were associated with women's slimmer waist, independently of both sexes' ages. Possible reasons for the waist effects were discussed, including women's abdominal body fat decreasing their own desire through neurohormonal mechanisms and decreasing their partner's desire through evolutionarily-related decreased sexual attractiveness.

  16. Cell-autonomous mechanisms of chronological aging in the yeast Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Anthony Arlia-Ciommo

    2014-05-01

    Full Text Available A body of evidence supports the view that the signaling pathways governing cellular aging – as well as mechanisms of their modulation by longevity-extending genetic, dietary and pharmacological interventions - are conserved across species. The scope of this review is to critically analyze recent advances in our understanding of cell-autonomous mechanisms of chronological aging in the budding yeast Saccharomyces cerevisiae. Based on our analysis, we propose a concept of a biomolecular network underlying the chronology of cellular aging in yeast. The concept posits that such network progresses through a series of lifespan checkpoints. At each of these checkpoints, the intracellular concentrations of some key intermediates and products of certain metabolic pathways - as well as the rates of coordinated flow of such metabolites within an intricate network of intercompartmental communications - are monitored by some checkpoint-specific ′′master regulator′′ proteins. The concept envisions that a synergistic action of these master regulator proteins at certain early-life and late-life checkpoints modulates the rates and efficiencies of progression of such processes as cell metabolism, growth, proliferation, stress resistance, macromolecular homeostasis, survival and death. The concept predicts that, by modulating these vital cellular processes throughout lifespan (i.e., prior to an arrest of cell growth and division, and following such arrest, the checkpoint-specific master regulator proteins orchestrate the development and maintenance of a pro- or anti-aging cellular pattern and, thus, define longevity of chronologically aging yeast.

  17. Cell-autonomous mechanisms of chronological aging in the yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Arlia-Ciommo, Anthony; Leonov, Anna; Piano, Amanda; Svistkova, Veronika; Titorenko, Vladimir I

    2014-05-27

    A body of evidence supports the view that the signaling pathways governing cellular aging - as well as mechanisms of their modulation by longevity-extending genetic, dietary and pharmacological interventions - are conserved across species. The scope of this review is to critically analyze recent advances in our understanding of cell-autonomous mechanisms of chronological aging in the budding yeast Saccharomyces cerevisiae . Based on our analysis, we propose a concept of a biomolecular network underlying the chronology of cellular aging in yeast. The concept posits that such network progresses through a series of lifespan checkpoints. At each of these checkpoints, the intracellular concentrations of some key intermediates and products of certain metabolic pathways - as well as the rates of coordinated flow of such metabolites within an intricate network of intercompartmental communications - are monitored by some checkpoint-specific "master regulator" proteins. The concept envisions that a synergistic action of these master regulator proteins at certain early-life and late-life checkpoints modulates the rates and efficiencies of progression of such processes as cell metabolism, growth, proliferation, stress resistance, macromolecular homeostasis, survival and death. The concept predicts that, by modulating these vital cellular processes throughout lifespan (i.e., prior to an arrest of cell growth and division, and following such arrest), the checkpoint-specific master regulator proteins orchestrate the development and maintenance of a pro- or anti-aging cellular pattern and, thus, define longevity of chronologically aging yeast.

  18. Effect of two-step aging on the mechanical properties of AA2219 DC cast alloy

    Energy Technology Data Exchange (ETDEWEB)

    Elgallad, E.M., E-mail: eelgalla@uqac.ca; Zhang, Z.; Chen, X.-G.

    2015-02-11

    With its combination of high specific strength, good machinability and excellent weldability, AA2219 direct chill (DC) cast alloy has become a new category of materials for manufacturing large molds for the plastics and automotive industries. The effect of two-step aging on the microstructural evolution and mechanical properties of AA2219 DC cast alloy was investigated. The precipitate microstructure was characterized under different heat treatment conditions using differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The poor mechanical properties of the air-quenched alloy were attributed to the presence of quench-induced coarse θ′ and θ precipitates, which had very limited contribution to the precipitation hardening during the aging treatment. The two-step aging treatment of the air-quenched AA2219 alloy involved the precipitation of GP zones in the first step followed by their transformation into fine θ″ strengthening precipitates in the second step, which considerably improved the mechanical properties. After undergoing 120 °C/36 h+190 °C/8 h two-step aging, the hardness, YS and UTS of the air-quenched alloy were increased by 27%, 46% and 15%, respectively, compared with 190 °C/8 h one-step aging.

  19. Mechanical Alterations Associated with Repeated Treadmill Sprinting under Heat Stress.

    Directory of Open Access Journals (Sweden)

    Olivier Girard

    Full Text Available Examine the mechanical alterations associated with repeated treadmill sprinting performed in HOT (38°C and CON (25°C conditions.Eleven recreationally active males performed a 30-min warm-up followed by three sets of five 5-s sprints with 25-s recovery and 3-min between sets in each environment. Constant-velocity running for 1-min at 10 and 20 km.h-1 was also performed prior to and following sprinting.Mean skin (37.2±0.7 vs. 32.7±0.8°C; P<0.001 and core (38.9±0.2 vs. 38.8±0.3°C; P<0.05 temperatures, together with thermal comfort (P<0.001 were higher following repeated sprinting in HOT vs. CON. Step frequency and vertical stiffness were lower (-2.6±1.6% and -5.5±5.5%; both P<0.001 and contact time (+3.2±2.4%; P<0.01 higher in HOT for the mean of sets 1-3 compared to CON. Running distance per sprint decreased from set 1 to 3 (-7.0±6.4%; P<0.001, with a tendency for shorter distance covered in HOT vs. CON (-2.7±3.4%; P = 0.06. Mean vertical (-2.6±5.5%; P<0.01, horizontal (-9.1±4.4%; P<0.001 and resultant ground reaction forces (-3.0±2.8%; P<0.01 along with vertical stiffness (-12.9±2.3%; P<0.001 and leg stiffness (-8.4±2.7%; P<0.01 decreased from set 1 to 3, independently of conditions. Propulsive power decreased from set 1 to 3 (-16.9±2.4%; P<0.001, with lower propulsive power values in set 2 (-6.6%; P<0.05 in HOT vs. CON. No changes in constant-velocity running patterns occurred between conditions, or from pre-to-post repeated-sprint exercise.Thermal strain alters step frequency and vertical stiffness during repeated sprinting; however without exacerbating mechanical alterations. The absence of changes in constant-velocity running patterns suggests a strong link between fatigue-induced velocity decrements during sprinting and mechanical alterations.

  20. Mechanical Alterations Associated with Repeated Treadmill Sprinting under Heat Stress

    Science.gov (United States)

    Brocherie, Franck; Morin, Jean-Benoit; Racinais, Sébastien; Millet, Grégoire P.; Périard, Julien D.

    2017-01-01

    Purpose Examine the mechanical alterations associated with repeated treadmill sprinting performed in HOT (38°C) and CON (25°C) conditions. Methods Eleven recreationally active males performed a 30-min warm-up followed by three sets of five 5-s sprints with 25-s recovery and 3-min between sets in each environment. Constant-velocity running for 1-min at 10 and 20 km.h-1 was also performed prior to and following sprinting. Results Mean skin (37.2±0.7 vs. 32.7±0.8°C; P<0.001) and core (38.9±0.2 vs. 38.8±0.3°C; P<0.05) temperatures, together with thermal comfort (P<0.001) were higher following repeated sprinting in HOT vs. CON. Step frequency and vertical stiffness were lower (-2.6±1.6% and -5.5±5.5%; both P<0.001) and contact time (+3.2±2.4%; P<0.01) higher in HOT for the mean of sets 1–3 compared to CON. Running distance per sprint decreased from set 1 to 3 (-7.0±6.4%; P<0.001), with a tendency for shorter distance covered in HOT vs. CON (-2.7±3.4%; P = 0.06). Mean vertical (-2.6±5.5%; P<0.01), horizontal (-9.1±4.4%; P<0.001) and resultant ground reaction forces (-3.0±2.8%; P<0.01) along with vertical stiffness (-12.9±2.3%; P<0.001) and leg stiffness (-8.4±2.7%; P<0.01) decreased from set 1 to 3, independently of conditions. Propulsive power decreased from set 1 to 3 (-16.9±2.4%; P<0.001), with lower propulsive power values in set 2 (-6.6%; P<0.05) in HOT vs. CON. No changes in constant-velocity running patterns occurred between conditions, or from pre-to-post repeated-sprint exercise. Conclusions Thermal strain alters step frequency and vertical stiffness during repeated sprinting; however without exacerbating mechanical alterations. The absence of changes in constant-velocity running patterns suggests a strong link between fatigue-induced velocity decrements during sprinting and mechanical alterations. PMID:28146582

  1. Eight common genetic variants associated with serum DHEAS levels suggest a key role in ageing mechanisms.

    Directory of Open Access Journals (Sweden)

    Guangju Zhai

    2011-04-01

    Full Text Available Dehydroepiandrosterone sulphate (DHEAS is the most abundant circulating steroid secreted by adrenal glands--yet its function is unknown. Its serum concentration declines significantly with increasing age, which has led to speculation that a relative DHEAS deficiency may contribute to the development of common age-related diseases or diminished longevity. We conducted a meta-analysis of genome-wide association data with 14,846 individuals and identified eight independent common SNPs associated with serum DHEAS concentrations. Genes at or near the identified loci include ZKSCAN5 (rs11761528; p = 3.15 × 10(-36, SULT2A1 (rs2637125; p =  2.61 × 10(-19, ARPC1A (rs740160; p =  1.56 × 10(-16, TRIM4 (rs17277546; p =  4.50 × 10(-11, BMF (rs7181230; p = 5.44 × 10(-11, HHEX (rs2497306; p =  4.64 × 10(-9, BCL2L11 (rs6738028; p = 1.72 × 10(-8, and CYP2C9 (rs2185570; p = 2.29 × 10(-8. These genes are associated with type 2 diabetes, lymphoma, actin filament assembly, drug and xenobiotic metabolism, and zinc finger proteins. Several SNPs were associated with changes in gene expression levels, and the related genes are connected to biological pathways linking DHEAS with ageing. This study provides much needed insight into the function of DHEAS.

  2. Mechanical and tribological behaviour of molten salt processed self-lubricated aluminium composite under different treatments

    Science.gov (United States)

    Kannan, C.; Ramanujam, R.

    2018-05-01

    The aim of this research work is to evaluate the mechanical and tribological behaviour of Al 7075 based self-lubricated hybrid nanocomposite under different treated conditions viz. as-cast, T6 and deep cryo treated. In order to overcome the drawbacks associated with conventional stir casting, a combinational approach that consists of molten salt processing, ultrasonic assistance and optimized mechanical stirring is adopted in this study to fabricate the nanocomposite. The mechanical characterisation tests carried out on this nanocomposite reveals an improvement of about 39% in hardness and 22% in ultimate tensile strength possible under T6 condition. Under specific conditions, the wear rate can be reduced to the extent of about 63% through the usage of self-lubricated hybrid nanocomposite under T6 condition.

  3. Surface Damage Mechanism of Monocrystalline Si Under Mechanical Loading

    Science.gov (United States)

    Zhao, Qingliang; Zhang, Quanli; To, Suet; Guo, Bing

    2017-03-01

    Single-point diamond scratching and nanoindentation on monocrystalline silicon wafer were performed to investigate the surface damage mechanism of Si under the contact loading. The results showed that three typical stages of material removal appeared during dynamic scratching, and a chemical reaction of Si with the diamond indenter and oxygen occurred under the high temperature. In addition, the Raman spectra of the various points in the scratching groove indicated that the Si-I to β-Sn structure (Si-II) and the following β-Sn structure (Si-II) to amorphous Si transformation appeared under the rapid loading/unloading condition of the diamond grit, and the volume change induced by the phase transformation resulted in a critical depth (ductile-brittle transition) of cut (˜60 nm ± 15 nm) much lower than the theoretical calculated results (˜387 nm). Moreover, it also led to abnormal load-displacement curves in the nanoindentation tests, resulting in the appearance of elbow and pop-out effects (˜270 nm at 20 s, 50 mN), which were highly dependent on the loading/unloading conditions. In summary, phase transformation of Si promoted surface deformation and fracture under both static and dynamic mechanical loading.

  4. High fidelity computational characterization of the mechanical response of thermally aged polycarbonate

    Science.gov (United States)

    Zhang, Zesheng; Zhang, Lili; Jasa, John; Li, Wenlong; Gazonas, George; Negahban, Mehrdad

    2017-07-01

    A representative all-atom molecular dynamics (MD) system of polycarbonate (PC) is built and conditioned to capture and predict the behaviours of PC in response to a broad range of thermo-mechanical loadings for various thermal aging. The PC system is constructed to have a distribution of molecular weights comparable to a widely used commercial PC (LEXAN 9034), and thermally conditioned to produce models for aged and unaged PC. The MD responses of these models are evaluated through comparisons to existing experimental results carried out at much lower loading rates, but done over a broad range of temperatures and loading modes. These experiments include monotonic extension/compression/shear, unilaterally and bilaterally confined compression, and load-reversal during shear. It is shown that the MD simulations show both qualitative and quantitative similarity with the experimental response. The quantitative similarity is evaluated by comparing the dilatational response under bilaterally confined compression, the shear flow viscosity and the equivalent yield stress. The consistency of the in silico response to real laboratory experiments strongly suggests that the current PC models are physically and mechanically relevant and potentially can be used to investigate thermo-mechanical response to loading conditions that would not easily be possible. These MD models may provide valuable insight into the molecular sources of certain observations, and could possibly offer new perspectives on how to develop constitutive models that are based on better understanding the response of PC under complex loadings. To this latter end, the models are used to predict the response of PC to complex loading modes that would normally be difficult to do or that include characteristics that would be difficult to measure. These include the responses of unaged and aged PC to unilaterally confined extension/compression, cyclic uniaxial/shear loadings, and saw-tooth extension/compression/shear.

  5. Epigenome-Wide Association Study of Cognitive Functioning in Middle-Aged Monozygotic Twins

    DEFF Research Database (Denmark)

    Starnawska, Anna; Tan, Qihua; McGue, Matt

    2017-01-01

    As the world's population ages, the age-related cognitive decline presents a great challenge to world's healthcare systems. One of the molecular mechanisms implicated in cognitive ageing is DNA methylation, an epigenetic modification known to be a key player in memory formation, maintenance......, and synaptic plasticity. Using the twin design we performed an epigenome-wide association study (EWAS) in a population of 486 middle-aged monozygotic twins (mean age at follow-up 65.9, SD = 6.1) and correlated their blood DNA methylation to their level (cross-sectional analysis) and change in cognitive...... abilities over 10 years (longitudinal analysis). We identified several CpG sites where cross-sectional cognitive functioning was associated with DNA methylation levels. The top identified loci were located in ZBTB46 (p = 5.84 × 10-7), and TAF12 (p = 4.91 × 10-7). KEGG's enrichment analyses of the most...

  6. Mechanical properties of cork under contact stresses

    International Nuclear Information System (INIS)

    Parralejo, A. D.; Guiberteau, F.; Fortes, M. A.; Rosa, M. E.

    2001-01-01

    In this work our interest is focussed on the mechanical behaviour of natural cork under contact stresses. Many of the applications of this curious material are related with its mechanical response under such a stress field, however this topic has not been still sufficiently considered in the scientific literature. For this purpose, we proposed the use of Hertzian indentation tests. By using this mythology we have investigated the cork structure influence on the corresponding mechanical properties. Our results reveal a clear mechanical anisotropy effect. Moreover, the elastic modulus corresponding to specific directions have been estimated. Several are the main advantages of this specific test mythology versus traditional uniaxial compression tests, specially simplicity and local character. (Author) 9 refs

  7. Leak-before-break analysis of thermally aged nuclear pipe under different bending moments

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Xuming; Li, Shilei; Zhang, Hailong; Wang, Yanli; Wang, Xitao [University of Science and Technology Beijing, Beijing (China); Wang, Zhaoxi [CPI Nuclear Power Institute, Beijing (China); Xue, Fei [Suzhou Nuclear Power Research Institute, Suzhou (China)

    2015-10-15

    Cast duplex stainless steels are susceptible to thermal aging during long-term service at temperatures ranging from 280°C to 450°C. To analyze the effect of thermal aging on leak-before-break (LBB) behavior, three-dimensional finite element analysis models were built for circumferentially cracked pipes. Based on the elastic–plastic fracture mechanics theory, the detectable leakage crack length calculation and J-integral stability assessment diagram approach were carried out under different bending moments. The LBB curves and LBB assessment diagrams for unaged and thermally aged pipes were constructed. The results show that the detectable leakage crack length for thermally aged pipes increases with increasing bending moments, whereas the critical crack length decreases. The ligament instability line and critical crack length line for thermally aged pipes move downward and to the left, respectively, and unsafe LBB assessment results will be produced if thermal aging is not considered. If the applied bending moment is increased, the degree of safety decreases in the LBB assessment.

  8. Reconciling genetic evolution and the associative learning account of mirror neurons through data-acquisition mechanisms.

    Science.gov (United States)

    Lotem, Arnon; Kolodny, Oren

    2014-04-01

    An associative learning account of mirror neurons should not preclude genetic evolution of its underlying mechanisms. On the contrary, an associative learning framework for cognitive development should seek heritable variation in the learning rules and in the data-acquisition mechanisms that construct associative networks, demonstrating how small genetic modifications of associative elements can give rise to the evolution of complex cognition.

  9. Aging of magnesium stearate under high doses gamma irradiation and oxidative conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lebeau, D.; Beuvier, L.; Cornaton, M. [CEA, DEN, DPC, SECR, LRMO, F-91191 Gif-sur-Yvette (France); Miserque, F. [CEA, DEN, DPC, SCCME, LECA, F-91191 Gif-sur-Yvette (France); Tabarant, M. [CEA, DEN, DPC, SEARS, LISL, F-91191 Gif-sur-Yvette (France); Esnouf, S. [CEA, DEN, DPC, SECR, LRMO, F-91191 Gif-sur-Yvette (France); Ferry, M., E-mail: muriel.ferry@cea.fr [CEA, DEN, DPC, SECR, LRMO, F-91191 Gif-sur-Yvette (France)

    2015-05-15

    Highlights: • Magnesium stearate was radio-oxidized at very high doses using gamma-rays. • H{sub 2} emission was estimated as a function of the integrated dose. • Modifications in the organic solid were followed as a function of the integrated dose. • A non-exhaustive degradation mechanism of magnesium stearate was proposed. - Abstract: In nuclear waste packages conditioning processes, magnesium stearate is widely used because of its high lubricating properties. For safety purposes, the radiolytic degradation of these organic materials has to be better understood to be able to predict their aging in repository conditions. This study reports the radiolytic degradation of magnesium stearate, using gamma-rays at room temperature and under air. Modifications were followed using different analytical tools (XPS, ATR-FTIR, ICP-AES, ATG and mass spectrometry). It has been observed that molecules mainly formed up to 1000 kGy of gamma irradiation dose under radio-oxidation are alkanes, hydroperoxides, double bonds in the aliphatic chain, carboxylates with aliphatic chain shorter than the one of stearate and ketones. At a dose of 4000 kGy, dicarboxylic acids are observed: the formation of these molecules needs a dose of at least 1000 kGy to be created under radio-oxidation. These observations allow us to propose a non-exhaustive degradation mechanism of magnesium stearate under gamma-irradiation at room temperature and under air.

  10. Organic chemical aging mechanisms: An annotated bibliography. Waste Tank Safety Program

    Energy Technology Data Exchange (ETDEWEB)

    Samuels, W.D.; Camaioni, D.M.; Nelson, D.A.

    1993-09-01

    An annotated bibliography has been compiled of the potential chemical and radiological aging mechanisms of the organic constituents (non-ferrocyanide) that would likely be found in the UST at Hanford. The majority of the work that has been conducted on the aging of organic chemicals used for extraction and processing of nuclear materials has been in conjunction with the acid or PUREX type processes. At Hanford the waste being stored in the UST has been stabilized with caustic. The aging factors that were used in this work were radiolysis, hydrolysis and nitrite/nitrate oxidation. The purpose of this work was two-fold: to determine whether or not research had been or is currently being conducted on the species associated with the Hanford UST waste, either as a mixture or as individual chemicals or chemical functionalities, and to determine what areas of chemical aging need to be addressed by further research.

  11. [The mechanisms of formation of liver injuries associated with the blunt abdominal trauma].

    Science.gov (United States)

    Pigolkin, Iu I; Dubrovina, I A; Dubrovin, I A

    2012-01-01

    The mechanisms of liver damage associated with the blunt abdominal trauma are considered based on the analysis of the literature publications. The general characteristic of these mechanisms and the processes underlying the development of liver injuries is presented. It is argued that the mechanisms underlying the formation of damages to the liver differ depending on the form of the traumatic impact, the injurious factor, and the processes leading to the destruction of the hepatic tissue. The main forms of traumatic impact in the case of a blunt abdominal trauma include the strike (blow), pressure, and concussion of the organ while the major traumatic factors are deformation, displacement, and "shock-resistant effects". The mechanisms underlying tissue destruction are compression and stretching. These two mechanisms are responsible for the formation of different variants of liver destruction. The results of the study suggest the necessity of the search for other mechanisms of degradation of the hepatic tissue following a blunt abdominal trauma for the improvement of forensic medical diagnostics of its cause and the underlying mechanism.

  12. The Continuum of Aging and Age-Related Diseases: Common Mechanisms but Different Rates

    Directory of Open Access Journals (Sweden)

    Claudio Franceschi

    2018-03-01

    Full Text Available Geroscience, the new interdisciplinary field that aims to understand the relationship between aging and chronic age-related diseases (ARDs and geriatric syndromes (GSs, is based on epidemiological evidence and experimental data that aging is the major risk factor for such pathologies and assumes that aging and ARDs/GSs share a common set of basic biological mechanisms. A consequence is that the primary target of medicine is to combat aging instead of any single ARD/GSs one by one, as favored by the fragmentation into hundreds of specialties and sub-specialties. If the same molecular and cellular mechanisms underpin both aging and ARDs/GSs, a major question emerges: which is the difference, if any, between aging and ARDs/GSs? The hypothesis that ARDs and GSs such as frailty can be conceptualized as accelerated aging will be discussed by analyzing in particular frailty, sarcopenia, chronic obstructive pulmonary disease, cancer, neurodegenerative diseases such as Alzheimer and Parkinson as well as Down syndrome as an example of progeroid syndrome. According to this integrated view, aging and ARDs/GSs become part of a continuum where precise boundaries do not exist and the two extremes are represented by centenarians, who largely avoided or postponed most ARDs/GSs and are characterized by decelerated aging, and patients who suffered one or more severe ARDs in their 60s, 70s, and 80s and show signs of accelerated aging, respectively. In between these two extremes, there is a continuum of intermediate trajectories representing a sort of gray area. Thus, clinically different, classical ARDs/GSs are, indeed, the result of peculiar combinations of alterations regarding the same, limited set of basic mechanisms shared with the aging process. Whether an individual will follow a trajectory of accelerated or decelerated aging will depend on his/her genetic background interacting lifelong with environmental and lifestyle factors. If ARDs and GSs are

  13. Mechanisms underlying the bioindicator notion: spatial association between individual sexual performance and community diversity.

    Directory of Open Access Journals (Sweden)

    Paola Laiolo

    Full Text Available The bioindicator notion is an appealing concept that has received more support in applied than in basic ecology, mostly due to the difficulty in deriving general ecological rules applicable to all target organisms. However, recognizing the mechanisms that determine the association between a particular species and the well-being of many other species is important for understanding the functioning of ecosystems and the relationship among different biological levels. We examined here the processes at the individual level that cause an association between species performance and biodiversity value, by analyzing attributes that can be studied in a variety of animals with sexual reproduction, namely breeding site selection and condition-dependent sexual signals. Our study model was the Capercaillie, an indicator of forest functioning and diversity, and the associated bird community, used here as a surrogate of broader forest biodiversity. At a regional scale Capercaillie occurrence was not associated with the most diverse forest patches, but at the scale of male spring territories the sexual display grounds (arenas were located in the oldest and less disturbed forest portions, which also hosted the richest local bird communities. Social mechanisms and conspecific cueing likely concurred with habitat-driven processes in determining the long-term persistence of traditional display grounds, which were appealing to many other species because of their structural composition. Characteristics of male vocal display that honestly advertize male quality (low frequencies and rapid song rates were significantly correlated with high diversity values, resulting in a spatial association between individual and community performances. Costly or risky activities such as reproductive or social behaviors, which more than other attributes match gradients in habitat quality, are therefore contributing to functionally connect individuals with ecosystem health.

  14. Ageing sintered silver: Relationship between tensile behavior, mechanical properties and the nanoporous structure evolution

    Energy Technology Data Exchange (ETDEWEB)

    Gadaud, Pascal; Caccuri, Vincenzo; Bertheau, Denis [Institut Pprime, Dept. Phys. Mech. Mat., UPR CNRS 3346, ENSMA, Université de Poitiers, 1 av. Clément Ader, Téléport 2, 86961 Futuroscope – Chasseneuil (France); Carr, James [HMXIF, Materials Science Centre, The University of Manchester, M13 9PL (United Kingdom); Milhet, Xavier, E-mail: xavier.milhet@ensma.fr [Institut Pprime, Dept. Phys. Mech. Mat., UPR CNRS 3346, ENSMA, Université de Poitiers, 1 av. Clément Ader, Téléport 2, 86961 Futuroscope – Chasseneuil (France)

    2016-07-04

    Silver pastes sintering is a potential candidate for die bonding in power electronic modules. The joints, obtained by sintering, exhibit a significant pore fraction thus reducing the density of the material compared to bulk silver. This was shown to alter drastically the mechanical properties (Young's modulus, yield strength and ultimate tensile stress) at room temperature. While careful analysis of the microstructure has been reported for the as-sintered material, little is known about its quantitative evolution (pores and grains) during thermal ageing. To address this issue, sintered bulk specimens and sintered joints were aged either under isothermal conditions (125 °C up to 1500 h) or under thermal cycling (between −40 °C/+125 °C with 30 min dwell time at each temperature for 2400 cycles). Under these conditions, it is shown that the density of the material does not change but the sub-micron porosity evolves towards a broader size distribution, consistent with Oswald ripening. It is also shown that only the step at 125 °C during the non-isothermal ageing is responsible for the microstructure evolution: isothermal ageing at high temperature can be regarded as a useful tool to perform accelerated ageing tests. Tensile properties are investigated as both a function of ageing time and a function of density. It is shown that the elastic properties do not evolve with the ageing time unlike the plastic properties. This is discussed as a function of the material microstructure evolution.

  15. Aging analysis of high performance FinFET flip-flop under Dynamic NBTI simulation configuration

    Science.gov (United States)

    Zainudin, M. F.; Hussin, H.; Halim, A. K.; Karim, J.

    2018-03-01

    A mechanism known as Negative-bias Temperature Instability (NBTI) degrades a main electrical parameters of a circuit especially in terms of performance. So far, the circuit design available at present are only focussed on high performance circuit without considering the circuit reliability and robustness. In this paper, the main circuit performances of high performance FinFET flip-flop such as delay time, and power were studied with the presence of the NBTI degradation. The aging analysis was verified using a 16nm High Performance Predictive Technology Model (PTM) based on different commands available at Synopsys HSPICE. The results shown that the circuit under the longer dynamic NBTI simulation produces the highest impact in the increasing of gate delay and decrease in the average power reduction from a fresh simulation until the aged stress time under a nominal condition. In addition, the circuit performance under a varied stress condition such as temperature and negative stress gate bias were also studied.

  16. Neural mechanisms underlying cognitive control of men with lifelong antisocial behavior.

    Science.gov (United States)

    Schiffer, Boris; Pawliczek, Christina; Mu Ller, Bernhard; Forsting, Michael; Gizewski, Elke; Leygraf, Norbert; Hodgins, Sheilagh

    2014-04-30

    Results of meta-analyses suggested subtle deficits in cognitive control among antisocial individuals. Because almost all studies focused on children with conduct problems or adult psychopaths, however, little is known about cognitive control mechanisms among the majority of persistent violent offenders who present an antisocial personality disorder (ASPD). The present study aimed to determine whether offenders with ASPD, relative to non-offenders, display dysfunction in the neural mechanisms underlying cognitive control and to assess the extent to which these dysfunctions are associated with psychopathic traits and trait impulsivity. Participants comprised 21 violent offenders and 23 non-offenders who underwent event-related functional magnetic resonance imaging while performing a non-verbal Stroop task. The offenders, relative to the non-offenders, exhibited reduced response time interference and a different pattern of conflict- and error-related activity in brain areas involved in cognitive control, attention, language, and emotion processing, that is, the anterior cingulate, dorsolateral prefrontal, superior temporal and postcentral cortices, putamen, thalamus, and amygdala. Moreover, between-group differences in behavioural and neural responses revealed associations with core features of psychopathy and attentional impulsivity. Thus, the results of the present study confirmed the hypothesis that offenders with ASPD display alterations in the neural mechanisms underlying cognitive control and that those alterations relate, at least in part, to personality characteristics. Copyright © 2014. Published by Elsevier Ireland Ltd.

  17. Hypothalamic ER–associated degradation regulates POMC maturation, feeding, and age-associated obesity

    Science.gov (United States)

    Kim, Geun Hyang; Somlo, Diane R.M.; Haataja, Leena; Song, Soobin; Nillni, Eduardo A.

    2018-01-01

    Pro-opiomelanocortin (POMC) neurons function as key regulators of metabolism and physiology by releasing prohormone-derived neuropeptides with distinct biological activities. However, our understanding of early events in prohormone maturation in the ER remains incomplete. Highlighting the significance of this gap in knowledge, a single POMC cysteine-to-phenylalanine mutation at position 28 (POMC-C28F) is defective for ER processing and causes early onset obesity in a dominant-negative manner in humans through an unclear mechanism. Here, we report a pathologically important role of Sel1L-Hrd1, the protein complex of ER-associated degradation (ERAD), within POMC neurons. Mice with POMC neuron–specific Sel1L deficiency developed age-associated obesity due, at least in part, to the ER retention of POMC that led to hyperphagia. The Sel1L-Hrd1 complex targets a fraction of nascent POMC molecules for ubiquitination and proteasomal degradation, preventing accumulation of misfolded and aggregated POMC, thereby ensuring that another fraction of POMC can undergo normal posttranslational processing and trafficking for secretion. Moreover, we found that the disease-associated POMC-C28F mutant evades ERAD and becomes aggregated due to the presence of a highly reactive unpaired cysteine thiol at position 50. Thus, this study not only identifies ERAD as an important mechanism regulating POMC maturation within the ER, but also provides insights into the pathogenesis of monogenic obesity associated with defective prohormone folding. PMID:29457782

  18. Dysregulation of the Bmi-1/p16Ink4a pathway provokes an aging-associated decline of submandibular gland function

    Science.gov (United States)

    Yamakoshi, Kimi; Katano, Satoshi; Iida, Mayu; Kimura, Hiromi; Okuma, Atsushi; Ikemoto-Uezumi, Madoka; Ohtani, Naoko; Hara, Eiji; Maruyama, Mitsuo

    2015-01-01

    Bmi-1 prevents stem cell aging, at least partly, by blocking expression of the cyclin-dependent kinase inhibitor p16Ink4a. Therefore, dysregulation of the Bmi-1/p16Ink4a pathway is considered key to the loss of tissue homeostasis and development of associated degenerative diseases during aging. However, because Bmi-1 knockout (KO) mice die within 20 weeks after birth, it is difficult to determine exactly where and when dysregulation of the Bmi-1/p16Ink4a pathway occurs during aging in vivo. Using real-time in vivo imaging of p16Ink4a expression in Bmi-1-KO mice, we uncovered a novel function of the Bmi-1/p16Ink4a pathway in controlling homeostasis of the submandibular glands (SMGs), which secrete saliva into the oral cavity. This pathway is dysregulated during aging in vivo, leading to induction of p16Ink4a expression and subsequent declined SMG function. These findings will advance our understanding of the molecular mechanisms underlying the aging-related decline of SMG function and associated salivary gland hypofunction, which is particularly problematic among the elderly. PMID:25832744

  19. Molecular mechanisms underlying formation of long-term reward memories and extinction memories in the honeybee (Apis mellifera)

    Science.gov (United States)

    2014-01-01

    The honeybee (Apis mellifera) has long served as an invertebrate model organism for reward learning and memory research. Its capacity for learning and memory formation is rooted in the ecological need to efficiently collect nectar and pollen during summer to ensure survival of the hive during winter. Foraging bees learn to associate a flower's characteristic features with a reward in a way that resembles olfactory appetitive classical conditioning, a learning paradigm that is used to study mechanisms underlying learning and memory formation in the honeybee. Due to a plethora of studies on appetitive classical conditioning and phenomena related to it, the honeybee is one of the best characterized invertebrate model organisms from a learning psychological point of view. Moreover, classical conditioning and associated behavioral phenomena are surprisingly similar in honeybees and vertebrates, suggesting a convergence of underlying neuronal processes, including the molecular mechanisms that contribute to them. Here I review current thinking on the molecular mechanisms underlying long-term memory (LTM) formation in honeybees following classical conditioning and extinction, demonstrating that an in-depth analysis of the molecular mechanisms of classical conditioning in honeybees might add to our understanding of associative learning in honeybees and vertebrates. PMID:25225299

  20. Post design evaluation (ageing mechanisms, effects, management, monitoring, PSR, ISI)

    International Nuclear Information System (INIS)

    Ichikawa, Toshio

    2001-01-01

    Although the nuclear plant was designed for the purpose of the 30-year life the early stages of construction, it also already has the plant abolished by passing in 30 years. There is a plant under operation and a plant that is employed variously, extends the original life and continues operation now, and the plant that is going to be abolished politically is before a life. By using a nuclear plant for a long period of time, damage. by the influence of irradiation, wear of slipping, corrosion, etc. appears. When this degradation is left, the serious accident is caused. In this lecture, refer to Assessment and management of ageing of major nuclear power plant components important to safety, Oct. 1999 of IAEA. A point of view from guide is introduced about management of the mechanism in the secular degradation mode expected by operating for a long period of time, the influence of secular degradation, and influence, monitoring technology, periodical safe evaluation, and a periodic inspection. And raises and explains the correspondence situation of secular degradation, and the example of evaluation of PSR and ISI equipment. The aging mechanism for reactor vessel internal components considered are related to embrittlement, fatigue, corrosion, radiation induced creep, relaxation and swelling, and mechanical wear. This lecture includes; monitoring methods, a description of periodic safety reviews and a sample of seismic design periodic safety report for the reactor internals

  1. Association mapping of soybean seed germination under salt stress.

    Science.gov (United States)

    Kan, Guizhen; Zhang, Wei; Yang, Wenming; Ma, Deyuan; Zhang, Dan; Hao, Derong; Hu, Zhenbin; Yu, Deyue

    2015-12-01

    Soil salinity is a serious threat to agriculture sustainability worldwide. Seed germination is a critical phase that ensures the successful establishment and productivity of soybeans in saline soils. However, little information is available regarding soybean salt tolerance at the germination stage. The objective of this study was to identify the genetic mechanisms of soybean seed germination under salt stress. One natural population consisting of 191 soybean landraces was used in this study. Soybean seeds produced in four environments were used to evaluate the salt tolerance at their germination stage. Using 1142 single-nucleotide polymorphisms (SNPs), the molecular markers associated with salt tolerance were detected by genome-wide association analysis. Eight SNP-trait associations and 13 suggestive SNP-trait associations were identified using a mixed linear model and the TASSEL 4.0 software. Eight SNPs or suggestive SNPs were co-associated with two salt tolerance indices, namely (1) the ratio of the germination index under salt conditions to the germination index under no-salt conditions (ST-GI) and (2) the ratio of the germination rate under salt conditions to the germination rate under no-salt conditions (ST-GR). One SNP (BARC-021347-04042) was significantly associated with these two traits (ST-GI and ST-GR). In addition, nine possible candidate genes were located in or near the genetic region where the above markers were mapped. Of these, five genes, Glyma08g12400.1, Glyma08g09730.1, Glyma18g47140.1, Glyma09g00460.1, and Glyma09g00490.3, were verified in response to salt stress at the germination stage. The SNPs detected could facilitate a better understanding of the genetic basis of soybean salt tolerance at the germination stage, and the marker BARC-021347-04042 could contribute to future breeding for soybean salt tolerance by marker-assisted selection.

  2. Search and the Aging Mind: The Promise and Limits of the Cognitive Control Hypothesis of Age Differences in Search.

    Science.gov (United States)

    Mata, Rui; von Helversen, Bettina

    2015-07-01

    Search is a prerequisite for successful performance in a broad range of tasks ranging from making decisions between consumer goods to memory retrieval. How does aging impact search processes in such disparate situations? Aging is associated with structural and neuromodulatory brain changes that underlie cognitive control processes, which in turn have been proposed as a domain-general mechanism controlling search in external environments as well as memory. We review the aging literature to evaluate the cognitive control hypothesis that suggests that age-related change in cognitive control underlies age differences in both external and internal search. We also consider the limits of the cognitive control hypothesis and propose additional mechanisms such as changes in strategy use and affect that may be necessary to understand how aging affects search. Copyright © 2015 Cognitive Science Society, Inc.

  3. Oxidative stress-induced telomeric erosion as a mechanism underlying airborne particulate matter-related cardiovascular disease

    Directory of Open Access Journals (Sweden)

    Grahame Thomas J

    2012-06-01

    Full Text Available Abstract Particulate matter (PM pollution is responsible for hundreds of thousands of deaths worldwide, the majority due to cardiovascular disease (CVD. While many potential pathophysiological mechanisms have been proposed, there is not yet a consensus as to which are most important in causing pollution-related morbidity/mortality. Nor is there consensus regarding which specific types of PM are most likely to affect public health in this regard. One toxicological mechanism linking exposure to airborne PM with CVD outcomes is oxidative stress, a contributor to the development of CVD risk factors including atherosclerosis. Recent work suggests that accelerated shortening of telomeres and, thus, early senescence of cells may be an important pathway by which oxidative stress may accelerate biological aging and the resultant development of age-related morbidity. This pathway may explain a significant proportion of PM-related adverse health outcomes, since shortened telomeres accelerate the progression of many diseases. There is limited but consistent evidence that vehicular emissions produce oxidative stress in humans. Given that oxidative stress is associated with accelerated erosion of telomeres, and that shortened telomeres are linked with acceleration of biological ageing and greater incidence of various age-related pathology, including CVD, it is hypothesized that associations noted between certain pollution types and sources and oxidative stress may reflect a mechanism by which these pollutants result in CVD-related morbidity and mortality, namely accelerated aging via enhanced erosion of telomeres. This paper reviews the literature providing links among oxidative stress, accelerated erosion of telomeres, CVD, and specific sources and types of air pollutants. If certain PM species/sources might be responsible for adverse health outcomes via the proposed mechanism, perhaps the pathway to reducing mortality/morbidity from PM would become clearer

  4. The effect of heat treatment on microstructure evolution in artificially aged carbon nanotube/Al2024 composites synthesized by mechanical alloying

    International Nuclear Information System (INIS)

    Pérez-Bustamante, R.; Pérez-Bustamante, F.; Maldonado-Orozco, M.C.; Martínez-Sánchez, R.

    2017-01-01

    Although carbon nanotubes/aluminum (CNT/Al) composites are promising materials in the production of structural components, their mechanical behavior under overaging conditions has not been considered. In this paper the effect of CNTs on the microstructural and mechanical behavior of a 2024 aluminum alloy (Al2024) synthesized by mechanical alloying (MA) and powder metallurgy routes is discussed, as well as the effect of aging heat treatments at different temperatures and aging times. The mechanical behavior of composites was screened by hardness measurements as function of aging time. After 96 h of aging time, composites showed mechanical stability in their hardness performance. Images from transmission electron microscopy showed that the mechanical stability of composites was due to a homogeneous dispersion of CNTs in the aluminum matrix and a subsequent alteration in the kinetics of precipitation is due to their presence in the aluminum matrix. Even though strengthening precipitation took place during aging, this was not the main strengthening mechanism observed in composites. - Highlights: • Dispersion of carbon nanotubes during mechanical alloying • Microstructural evolution observed by HRTEM. • Mechanical performance evaluated through micro-hardness test. • Increased mechanical performance at high working temperatures • Acceleration of kinetics of precipitation due to CNTs, and milling conditions

  5. The effect of heat treatment on microstructure evolution in artificially aged carbon nanotube/Al2024 composites synthesized by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Pérez-Bustamante, R. [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología, Miguel de Cervantes No.120, C.P. 31109 Chihuahua, Chih. (Mexico); Pérez-Bustamante, F. [Universidad Autónoma de Chihuahua (UACH), Facultad de Ciencias Químicas, Circuito No. 1 Nuevo Campus Universitario, C.P. 31125 Chihuahua, Chih. (Mexico); Maldonado-Orozco, M.C. [Universidad Autónoma de Chihuahua (UACH), Facultad de Ingeniería, Circuito No. 1 Nuevo Campus Universitario, C.P. 31125 Chihuahua, Chih. (Mexico); Martínez-Sánchez, R., E-mail: roberto.martinez@cimav.edu.mx [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología, Miguel de Cervantes No.120, C.P. 31109 Chihuahua, Chih. (Mexico)

    2017-04-15

    Although carbon nanotubes/aluminum (CNT/Al) composites are promising materials in the production of structural components, their mechanical behavior under overaging conditions has not been considered. In this paper the effect of CNTs on the microstructural and mechanical behavior of a 2024 aluminum alloy (Al2024) synthesized by mechanical alloying (MA) and powder metallurgy routes is discussed, as well as the effect of aging heat treatments at different temperatures and aging times. The mechanical behavior of composites was screened by hardness measurements as function of aging time. After 96 h of aging time, composites showed mechanical stability in their hardness performance. Images from transmission electron microscopy showed that the mechanical stability of composites was due to a homogeneous dispersion of CNTs in the aluminum matrix and a subsequent alteration in the kinetics of precipitation is due to their presence in the aluminum matrix. Even though strengthening precipitation took place during aging, this was not the main strengthening mechanism observed in composites. - Highlights: • Dispersion of carbon nanotubes during mechanical alloying • Microstructural evolution observed by HRTEM. • Mechanical performance evaluated through micro-hardness test. • Increased mechanical performance at high working temperatures • Acceleration of kinetics of precipitation due to CNTs, and milling conditions.

  6. Effect of aging time and aging temperature on fatigue and fracture behavior of 6063 aluminum alloy under seawater influence

    International Nuclear Information System (INIS)

    Siddiqui, R.A.; Abdul-Wahab, S.A.; Pervez, T.

    2008-01-01

    This paper describes experimentally the effect of seawater corrosion, aging time, and aging temperature on the fatigue resistance property of 6063 aluminum alloy. The 6063 aluminum alloy that was used for the study was heat treated and soaked in seawater for different intervals of time between 2 and 30 weeks. It was found that the maximum fatigue resistance property in the 6063 aluminum alloy was observed when aged between 7 and 9 h and heat treated at temperatures between 160 o C and 200 o C. Generally at constant load, the results indicated that the number of cycles to fail the 6063 aluminum alloy decreased with increasing the soaking time in seawater. Moreover, fracture surfaces were considered and studied under a scanning electron microscope (SEM). The results showed that the brittle fracture pattern tended to occur with the increase in aging time and temperature. The fatigue striations were observed very clearly at low and peak aging temperature. The increase in the fatigue resistance property with aging time was linked with the vacancies assisted diffusion mechanism and also by the hindering of dislocation movement by impure atoms

  7. Mechanical Properties and Corrosion Characteristics of Thermally Aged Alloy 22

    International Nuclear Information System (INIS)

    Rebak, R B; Crook, P

    2002-01-01

    Alloy 22 (UNS N06022) is a candidate material for the external wall of the high level nuclear waste containers for the potential repository site at Yucca Mountain. In the mill-annealed (MA) condition, Alloy 22 is a single face centered cubic phase. When exposed to temperatures on the order of 600 C and above for times higher than 1 h, this alloy may develop secondary phases that reduce its mechanical toughness and corrosion resistance. The objective of this work was to age Alloy 22 at temperatures between 482 C and 760 C for times between 0.25 h and 6,000 h and to study the mechanical and corrosion performance of the resulting material. Aging was carried out using wrought specimens as well as gas tungsten arc welded (GTAW) specimens. Mechanical and corrosion testing was carried out using ASTM standards. Results show-that the higher the aging temperature and the longer the aging time, the lower the impact toughness of the aged material and the lower its corrosion resistance. However, extrapolating both mechanical and corrosion laboratory data predicts that Alloy 22 will remain corrosion resistant and mechanically robust for the projected lifetime of the waste container

  8. Using Drosophila to discover mechanisms underlying type 2 diabetes

    Directory of Open Access Journals (Sweden)

    Ronald W. Alfa

    2016-04-01

    Full Text Available Mechanisms of glucose homeostasis are remarkably well conserved between the fruit fly Drosophila melanogaster and mammals. From the initial characterization of insulin signaling in the fly came the identification of downstream metabolic pathways for nutrient storage and utilization. Defects in these pathways lead to phenotypes that are analogous to diabetic states in mammals. These discoveries have stimulated interest in leveraging the fly to better understand the genetics of type 2 diabetes mellitus in humans. Type 2 diabetes results from insulin insufficiency in the context of ongoing insulin resistance. Although genetic susceptibility is thought to govern the propensity of individuals to develop type 2 diabetes mellitus under appropriate environmental conditions, many of the human genes associated with the disease in genome-wide association studies have not been functionally studied. Recent advances in the phenotyping of metabolic defects have positioned Drosophila as an excellent model for the functional characterization of large numbers of genes associated with type 2 diabetes mellitus. Here, we examine results from studies modeling metabolic disease in the fruit fly and compare findings to proposed mechanisms for diabetic phenotypes in mammals. We provide a systematic framework for assessing the contribution of gene candidates to insulin-secretion or insulin-resistance pathways relevant to diabetes pathogenesis.

  9. Factors associated with exclusive breastfeeding among infants under six months of age in peninsular malaysia

    Directory of Open Access Journals (Sweden)

    Tan Kok

    2011-02-01

    Full Text Available Abstract Background Breastfeeding is accepted as the natural form of infant feeding. For mothers to be able to breastfeed exclusively to the recommended six months, it is important to understand the factors that influence exclusive breastfeeding. The aim of the study was to identify factors associated with exclusive breastfeeding in Peninsular Malaysia. Methods This was a cross-sectional study involving 682 mother-infant pairs with infants up to six months attending maternal and child health section of the government health clinics in Klang, Malaysia. Data were collected by face-to-face interviews using a pre-tested structured questionnaire over 4 months in 2006. Data on breastfeeding were based on practice in the previous one month period. Logistic regression was used to assess the independent association between the independent variables and exclusive breastfeeding adjusting for infant age. Results The prevalence of exclusive breastfeeding among mothers with infants aged between one and six months was 43.1% (95% CI: 39.4, 46.8. In the multivariate model exclusive breastfeeding was positively associated with rural residence, Malay mothers, non-working and non-smoking mothers, multiparous mothers, term infants, mothers with husbands who support breastfeeding and mothers who practice bed-sharing. Conclusions Interventions that seek to increase exclusive breastfeeding should focus on women who are at risk of early discontinuation of breastfeeding.

  10. Aging-associated oxidative stress leads to decrease in IAS tone via RhoA/ROCK downregulation.

    Science.gov (United States)

    Singh, Jagmohan; Kumar, Sumit; Krishna, Chadalavada Vijay; Rattan, Satish

    2014-06-01

    Internal anal sphincter (IAS) tone plays an important role in rectoanal incontinence (RI). IAS tone may be compromised during aging, leading to RI in certain patients. We examined the influence of oxidative stress in the aging-associated decrease in IAS tone (AADI). Using adult (4-6 mo old) and aging (24-30 mo old) rats, we determined the effect of oxidative stress on IAS tone and the regulatory RhoA/ROCK signal transduction cascade. We determined the effect of the oxidative stress inducer LY83583, which produces superoxide anions (O2 (·-)), on basal and stimulated IAS tone before and after treatment of intact smooth muscle strips and smooth muscle cells with the O2 (·-) scavenger SOD. Our data showed that AADI was associated with a decrease in RhoA/ROCK expression at the transcriptional and translational levels. Oxidative stress with a LY83583-mediated decrease in IAS tone and relaxation of IAS smooth muscle cells was associated with a decrease in RhoA/ROCK signal transduction, which was reversible by SOD. In addition, LY83583 caused a significant decrease in IAS contraction produced by the RhoA activator and a known RhoA/ROCK agonist, U46619, that was also reversible by SOD. The inhibitory effects of LY83583 and the ROCK inhibitor Y27632 on the U46619-induced increase in IAS tone were similar. We conclude that an increase in oxidative stress plays an important role in AADI in the elderly and may be one of the underlying mechanisms of RI in certain aging patients. Copyright © 2014 the American Physiological Society.

  11. Histologic and biochemical alterations predict pulmonary mechanical dysfunction in aging mice with chronic lung inflammation.

    Directory of Open Access Journals (Sweden)

    Christopher B Massa

    2017-08-01

    Full Text Available Both aging and chronic inflammation produce complex structural and biochemical alterations to the lung known to impact work of breathing. Mice deficient in surfactant protein D (Sftpd develop progressive age-related lung pathology characterized by tissue destruction/remodeling, accumulation of foamy macrophages and alteration in surfactant composition. This study proposes to relate changes in tissue structure seen in normal aging and in chronic inflammation to altered lung mechanics using a computational model. Alterations in lung function in aging and Sftpd -/- mice have been inferred from fitting simple mechanical models to respiratory impedance data (Zrs, however interpretation has been confounded by the simultaneous presence of multiple coexisting pathophysiologic processes. In contrast to the inverse modeling approach, this study uses simulation from experimental measurements to recapitulate how aging and inflammation alter Zrs. Histologic and mechanical measurements were made in C57BL6/J mice and congenic Sftpd-/- mice at 8, 27 and 80 weeks of age (n = 8/group. An anatomic computational model based on published airway morphometry was developed and Zrs was simulated between 0.5 and 20 Hz. End expiratory pressure dependent changes in airway caliber and recruitment were estimated from mechanical measurements. Tissue elements were simulated using the constant phase model of viscoelasticity. Baseline elastance distribution was estimated in 8-week-old wild type mice, and stochastically varied for each condition based on experimentally measured alteration in elastic fiber composition, alveolar geometry and surfactant composition. Weighing reduction in model error against increasing model complexity allowed for identification of essential features underlying mechanical pathology and their contribution to Zrs. Using a maximum likelihood approach, alteration in lung recruitment and diminished elastic fiber density were shown predictive of mechanical

  12. Histologic and biochemical alterations predict pulmonary mechanical dysfunction in aging mice with chronic lung inflammation.

    Science.gov (United States)

    Massa, Christopher B; Groves, Angela M; Jaggernauth, Smita U; Laskin, Debra L; Gow, Andrew J

    2017-08-01

    Both aging and chronic inflammation produce complex structural and biochemical alterations to the lung known to impact work of breathing. Mice deficient in surfactant protein D (Sftpd) develop progressive age-related lung pathology characterized by tissue destruction/remodeling, accumulation of foamy macrophages and alteration in surfactant composition. This study proposes to relate changes in tissue structure seen in normal aging and in chronic inflammation to altered lung mechanics using a computational model. Alterations in lung function in aging and Sftpd -/- mice have been inferred from fitting simple mechanical models to respiratory impedance data (Zrs), however interpretation has been confounded by the simultaneous presence of multiple coexisting pathophysiologic processes. In contrast to the inverse modeling approach, this study uses simulation from experimental measurements to recapitulate how aging and inflammation alter Zrs. Histologic and mechanical measurements were made in C57BL6/J mice and congenic Sftpd-/- mice at 8, 27 and 80 weeks of age (n = 8/group). An anatomic computational model based on published airway morphometry was developed and Zrs was simulated between 0.5 and 20 Hz. End expiratory pressure dependent changes in airway caliber and recruitment were estimated from mechanical measurements. Tissue elements were simulated using the constant phase model of viscoelasticity. Baseline elastance distribution was estimated in 8-week-old wild type mice, and stochastically varied for each condition based on experimentally measured alteration in elastic fiber composition, alveolar geometry and surfactant composition. Weighing reduction in model error against increasing model complexity allowed for identification of essential features underlying mechanical pathology and their contribution to Zrs. Using a maximum likelihood approach, alteration in lung recruitment and diminished elastic fiber density were shown predictive of mechanical alteration at

  13. Giant panda׳s tooth enamel: Structure, mechanical behavior and toughening mechanisms under indentation.

    Science.gov (United States)

    Weng, Z Y; Liu, Z Q; Ritchie, R O; Jiao, D; Li, D S; Wu, H L; Deng, L H; Zhang, Z F

    2016-12-01

    The giant panda׳s teeth possess remarkable load-bearing capacity and damage resistance for masticating bamboos. In this study, the hierarchical structure and mechanical behavior of the giant panda׳s tooth enamel were investigated under indentation. The effects of loading orientation and location on mechanical properties of the enamel were clarified and the evolution of damage in the enamel under increasing load evaluated. The nature of the damage, both at and beneath the indentation surfaces, and the underlying toughening mechanisms were explored. Indentation cracks invariably were seen to propagate along the internal interfaces, specifically the sheaths between enamel rods, and multiple extrinsic toughening mechanisms, e.g., crack deflection/twisting and uncracked-ligament bridging, were active to shield the tips of cracks from the applied stress. The giant panda׳s tooth enamel is analogous to human enamel in its mechanical properties, yet it has superior hardness and Young׳s modulus but inferior toughness as compared to the bamboo that pandas primarily feed on, highlighting the critical roles of the integration of underlying tissues in the entire tooth and the highly hydrated state of bamboo foods. Our objective is that this study can aid the understanding of the structure-mechanical property relations in the tooth enamel of mammals and further provide some insight on the food habits of the giant pandas. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Mechanism of Homologous Recombination and Implications for Aging-Related Deletions in Mitochondrial DNA

    Science.gov (United States)

    2013-01-01

    SUMMARY Homologous recombination is a universal process, conserved from bacteriophage to human, which is important for the repair of double-strand DNA breaks. Recombination in mitochondrial DNA (mtDNA) was documented more than 4 decades ago, but the underlying molecular mechanism has remained elusive. Recent studies have revealed the presence of a Rad52-type recombination system of bacteriophage origin in mitochondria, which operates by a single-strand annealing mechanism independent of the canonical RecA/Rad51-type recombinases. Increasing evidence supports the notion that, like in bacteriophages, mtDNA inheritance is a coordinated interplay between recombination, repair, and replication. These findings could have profound implications for understanding the mechanism of mtDNA inheritance and the generation of mtDNA deletions in aging cells. PMID:24006472

  15. Age-related declines and disease-associated variation in immune cell telomere length in a wild mammal.

    Directory of Open Access Journals (Sweden)

    Christopher Beirne

    Full Text Available Immunosenescence, the deterioration of immune system capability with age, may play a key role in mediating age-related declines in whole-organism performance, but the mechanisms that underpin immunosenescence are poorly understood. Biomedical research on humans and laboratory models has documented age and disease related declines in the telomere lengths of leukocytes ('immune cells', stimulating interest their having a potentially general role in the emergence of immunosenescent phenotypes. However, it is unknown whether such observations generalise to the immune cell populations of wild vertebrates living under ecologically realistic conditions. Here we examine longitudinal changes in the mean telomere lengths of immune cells in wild European badgers (Meles meles. Our findings provide the first evidence of within-individual age-related declines in immune cell telomere lengths in a wild vertebrate. That the rate of age-related decline in telomere length appears to be steeper within individuals than at the overall population level raises the possibility that individuals with short immune cell telomeres and/or higher rates of immune cell telomere attrition may be selectively lost from this population. We also report evidence suggestive of associations between immune cell telomere length and bovine tuberculosis infection status, with individuals detected at the most advanced stage of infection tending to have shorter immune cell telomeres than disease positive individuals. While male European badgers are larger and show higher rates of annual mortality than females, we found no evidence of a sex difference in either mean telomere length or the average rate of within-individual telomere attrition with age. Our findings lend support to the view that age-related declines in the telomere lengths of immune cells may provide one potentially general mechanism underpinning age-related declines in immunocompetence in natural populations.

  16. Normal breast tissue DNA methylation differences at regulatory elements are associated with the cancer risk factor age.

    Science.gov (United States)

    Johnson, Kevin C; Houseman, E Andres; King, Jessica E; Christensen, Brock C

    2017-07-10

    The underlying biological mechanisms through which epidemiologically defined breast cancer risk factors contribute to disease risk remain poorly understood. Identification of the molecular changes associated with cancer risk factors in normal tissues may aid in determining the earliest events of carcinogenesis and informing cancer prevention strategies. Here we investigated the impact cancer risk factors have on the normal breast epigenome by analyzing DNA methylation genome-wide (Infinium 450 K array) in cancer-free women from the Susan G. Komen Tissue Bank (n = 100). We tested the relation of established breast cancer risk factors, age, body mass index, parity, and family history of disease, with DNA methylation adjusting for potential variation in cell-type proportions. We identified 787 cytosine-guanine dinucleotide (CpG) sites that demonstrated significant associations (Q value breast cancer risk factors. Age-related DNA methylation changes are primarily increases in methylation enriched at breast epithelial cell enhancer regions (P = 7.1E-20), and binding sites of chromatin remodelers (MYC and CTCF). We validated the age-related associations in two independent populations, using normal breast tissue samples (n = 18) and samples of normal tissue adjacent to tumor tissue (n = 97). The genomic regions classified as age-related were more likely to be regions altered in both pre-invasive (n = 40, P = 3.0E-03) and invasive breast tumors (n = 731, P = 1.1E-13). DNA methylation changes with age occur at regulatory regions, and are further exacerbated in cancer, suggesting that age influences breast cancer risk in part through its contribution to epigenetic dysregulation in normal breast tissue.

  17. Prevalence and associated risk factors of under nutrition among children aged 6 to 59 months in internally displaced persons of jalozai camp, District Nowshera, Khyber Pakhtunkhwa

    International Nuclear Information System (INIS)

    Ali, W.; Ayub, A.; Hussain, H.

    2015-01-01

    Background: The magnitude of under nutrition among children below five years of age is high in Pakistan. Undernutrition and infections are the two most important factors that affect the growth of children. This study explains the extent of undernutrition and prevalence of wasting and stunting among preschool children. Method: This cross sectional study with a sample size of 446 covered the age group 6-59 months in Jalozai Camp, District Nowshera. Height for age, weight for age and weight for height were measured as per WHO guidelines. Systematic random sampling technique was used for sample selection. Data was collected using a questionnaire. Results: According to height for age Z-score, out of 446 children studied, 8.5 percentage were stunted and 4.0 percentage were severely stunted. According to weight for age Z score, 11.4 percentage were underweight and 3.6 percentage were severely underweight. According to weight for height Z-score, 4.0 percentage were wasted and 2.7 percentage were severely wasted. Conclusion: The undernutrition in children is comparable to the national figures. Although our study found that absence of formal education, big family size, late and early weaning, absence of exclusive breast feeding and poverty were the factors associated with undernutrition in children, they could cause increase in under nutrition in future if not improved. (author)

  18. Iron overload in a murine model of hereditary hemochromatosis is associated with accelerated progression of osteoarthritis under mechanical stress.

    Science.gov (United States)

    Camacho, A; Simão, M; Ea, H-K; Cohen-Solal, M; Richette, P; Branco, J; Cancela, M L

    2016-03-01

    Hereditary hemochromatosis (HH) is a disease caused by mutations in the Hfe gene characterised by systemic iron overload and associated with an increased prevalence of osteoarthritis (OA) but the role of iron overload in the development of OA is still undefined. To further understand the molecular mechanisms involved we have used a murine model of HH and studied the progression of experimental OA under mechanical stress. OA was surgically induced in the knee joints of 10-week-old C57BL6 (wild-type) mice and Hfe-KO mice. OA progression was assessed using histology, micro CT, gene expression and immunohistochemistry at 8 weeks after surgery. Hfe-KO mice showed a systemic iron overload and an increased iron accumulation in the knee synovial membrane following surgery. The histological OA score was significantly higher in the Hfe-KO mice at 8 weeks after surgery. Micro CT study of the proximal tibia revealed increased subchondral bone volume and increased trabecular thickness. Gene expression and immunohistochemical analysis showed a significant increase in the expression of matrix metallopeptidase 3 (MMP-3) in the joints of Hfe-KO mice compared with control mice at 8 weeks after surgery. HH was associated with an accelerated development of OA in mice. Our findings suggest that synovial iron overload has a definite role in the progression of HH-related OA. Copyright © 2015 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  19. Microstructures and mechanical properties of aging materials

    International Nuclear Information System (INIS)

    Liaw, P.K.; Viswanathan, R.; Murty, K.L.; Simonen, E.P.; Frear, D.

    1993-01-01

    This book contains a collection of papers presented at the symposium on ''Microstructures and Mechanical Properties of Aging Materials,'' that was held in Chicago, IL. November 2-5, 1992 in conjunction with the Fall Meeting of The Minerals, Metals and Materials Society (TMS). The subjects of interest in the symposium included: (1) mechanisms of microstructural degradation, (2) effects of microstructural degradation on mechanical behavior, (3) development of life prediction methodology for in-service structural and electronic components, (4) experimental techniques to monitor degradation of microstructures and mechanical properties, and (5) effects of environment on microstructural degradation and mechanical properties. Individual papers have been processed separately for inclusion in the appropriate data bases

  20. Age Group Differences in Perceived Age Discrimination: Associations With Self-Perceptions of Aging.

    Science.gov (United States)

    Giasson, Hannah L; Queen, Tara L; Larkina, Marina; Smith, Jacqui

    2017-08-01

    From midlife onwards, age stereotypes increasingly underlie social judgments and contribute to age-based discrimination. Whereas many studies compare differences between young and older adults in reports of age discrimination or sensitivity to age stereotypes, few consider age group differences among adults over 50. We form subgroups corresponding to social age group membership (early midlife, late midlife, young old, oldest old) and examine differences in reported experiences of everyday age discrimination and associations with self-perceptions of aging. Using cross-sectional and longitudinal data from the Health and Retirement Study (HRS: N = 15,071; M Age = 68, range 50-101), multivariate logistic regression was used to examine experiences of everyday discrimination attributed to age, and associations between age discrimination and self-perceptions of aging, in four age groups: early midlife, late midlife, young old, oldest old. People in the early midlife group (aged 50-59) reported more experiences of unfair treatment than the older age groups but were less likely to attribute their experiences to age discrimination. After controlling for covariates, individuals in all age groups who perceived their own aging positively were less likely to report experiences of age discrimination. The magnitude of this effect, however, was greatest in the early midlife group. Findings support proposals that midlife is a pivotal life period when individuals adjust to life events and social role transitions. Future longitudinal studies will provide further insight into whether positive self-perceptions of aging are especially important in this phase of the life course. © The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Peeling mechanism of tomato under infrared heating

    Science.gov (United States)

    Critical behaviors of peeling tomatoes using infrared heat are thermally induced peel loosening and subsequent cracking. However, the mechanism of peel loosening and cracking due to infrared heating remains unclear. This study aimed at investigating the mechanism of peeling tomatoes under infrared h...

  2. Peripheral Receptor Mechanisms Underlying Orofacial Muscle Pain and Hyperalgesia

    Science.gov (United States)

    Saloman, Jami L.

    Musculoskeletal pain conditions, particularly those associated with temporomandibular joint and muscle disorders (TMD) are severely debilitating and affect approximately 12% of the population. Identifying peripheral nociceptive mechanisms underlying mechanical hyperalgesia, a prominent feature of persistent muscle pain, could contribute to the development of new treatment strategies for the management of TMD and other muscle pain conditions. This study provides evidence of functional interactions between ligand-gated channels, P2X3 and TRPV1/TRPA1, in trigeminal sensory neurons, and proposes that these interactions underlie the development of mechanical hyperalgesia. In the masseter muscle, direct P2X3 activation, via the selective agonist αβmeATP, induced a dose- and time-dependent hyperalgesia. Importantly, the αβmeATP-induced hyperalgesia was prevented by pretreatment of the muscle with a TRPV1 antagonist, AMG9810, or the TRPA1 antagonist, AP18. P2X3 was co-expressed with both TRPV1 and TRPA1 in masseter muscle afferents confirming the possibility for intracellular interactions. Moreover, in a subpopulation of P2X3 /TRPV1 positive neurons, capsaicin-induced Ca2+ transients were significantly potentiated following P2X3 activation. Inhibition of Ca2+-dependent kinases, PKC and CaMKII, prevented P2X3-mechanical hyperalgesia whereas blockade of Ca2+-independent PKA did not. Finally, activation of P2X3 induced phosphorylation of serine, but not threonine, residues in TRPV1 in trigeminal sensory neurons. Significant phosphorylation was observed at 15 minutes, the time point at which behavioral hyperalgesia was prominent. Similar data were obtained regarding another nonselective cation channel, the NMDA receptor (NMDAR). Our data propose P2X3 and NMDARs interact with TRPV1 in a facilitatory manner, which could contribute to the peripheral sensitization underlying masseter hyperalgesia. This study offers novel mechanisms by which individual pro-nociceptive ligand

  3. Age-Associated Lipidome Changes in Metaphase II Mouse Oocytes.

    Directory of Open Access Journals (Sweden)

    Hyuck Jun Mok

    Full Text Available The quality of mammalian oocytes declines with age, which negatively affects fertilization and developmental potential. The aging process often accompanies damages to macromolecules such as proteins, DNA, and lipids. To investigate if aged oocytes display an altered lipidome compared to young oocytes, we performed a global lipidomic analysis between oocytes from 4-week-old and 42 to 50-week-old mice. Increased oxidative stress is often considered as one of the main causes of cellular aging. Thus, we set up a group of 4-week-old oocytes treated with hydrogen peroxide (H2O2, a commonly used oxidative stressor, to compare if similar lipid species are altered between aged and oxidative-stressed oocytes. Between young and aged oocytes, we identified 26 decreased and 6 increased lipids in aged oocytes; and between young and H2O2-treated oocytes, we identified 35 decreased and 26 increased lipids in H2O2-treated oocytes. The decreased lipid species in these two comparisons were overlapped, whereas the increased lipid species were distinct. Multiple phospholipid classes, phosphatidic acid (PA, phosphatidylinositol (PI, phosphatidylserine (PS, and lysophosphatidylserine (LPS significantly decreased both in H2O2-treated and aged oocytes, suggesting that the integrity of plasma membrane is similarly affected under these conditions. In contrast, a dramatic increase in diacylglycerol (DG was only noted in H2O2-treated oocytes, indicating that the acute effect of H2O2-caused oxidative stress is distinct from aging-associated lipidome alteration. In H2O2-treated oocytes, the expression of lysophosphatidylcholine acyltransferase 1 increased along with increases in phosphatidylcholine. Overall, our data reveal that several classes of phospholipids are affected in aged oocytes, suggesting that the integrity of plasma membrane is associated with maintaining fertilization and developmental potential of mouse oocytes.

  4. Is vaginal reflux associated with urinary tract infection in female children under the age of 36 months?

    Science.gov (United States)

    Kim, Yu Bin; Tang, Chih Lung; Koo, Ja Wook

    2018-01-01

    To determine the relationship between vaginal reflux (VR) and urinary tract infection (UTI) in female children aged UTI, who underwent a voiding cystourethrography (VCUG) for assessment of vesicoureteral reflux (VUR) at Sanggye Paik Hospital. Fifty-one girls, who underwent VCUG for assessment of congenital hydronephrosis or renal pelvis dilatation, without a UTI, formed the control group. The correlation between the presence and grade of VR and UTI was evaluated. The prevalence rate of VR was higher in the UTI (42.9%) than control (13.7%) group ( P UTI (mean, 0.64) than control (mean, 0.18) group ( P UTI group: n=126, age, 5.28±2.13 months; control group: n=22, age, 4.79±2.40 months; P =0.33), both VR prevalence (43.65% vs. 18.18%, P UTI than control group. Presence and higher grade of VR were associated with UTI recurrence ( P UTI, the risk of renal defect increases. Occurrence of VR is associated with UTI recurrence and urosepsis in pediatric female patients.

  5. Reinforcing effects of cigarette advertising on under-age smoking.

    Science.gov (United States)

    Aitken, P P; Eadie, D R

    1990-03-01

    Interviews were conducted with 848 Glasgow children aged between 11 and 14 years. There were consistent differences between smokers and non-smokers. Smokers tended to be more adept at recalling, recognizing and identifying cigarette advertisements. This suggests they tend to pay more attention to cigarette advertising. Smokers also tended to be generally more appreciative of cigarette advertising. Moreover, this greater awareness and appreciation of cigarette advertising was independent of other important predictors of under-age smoking, such as smoking by peers, siblings and parents. These findings, taken in conjunction with previous research, indicate that cigarette advertising is reinforcing under-age smoking. The smokers showed an enhanced or heightened preference for Kensitas Club, the brand favoured by adults. This is consistent with previous research indicating that promotional devices which help determine and reinforce adult cigarette brand preferences have an even greater effect on under-age smokers.

  6. Age and sex influences on running mechanics and coordination variability.

    Science.gov (United States)

    Boyer, Katherine A; Freedman Silvernail, Julia; Hamill, Joseph

    2017-11-01

    The purpose of this study was to examine the impact of age on running mechanics separately for male and female runners and to quantify sex differences in running mechanics and coordination variability for older runners. Kinematics and kinetics were captured for 20 younger (10 male) and 20 older (10 male) adults running overground at 3.5 m · s -1 . A modified vector coding technique was used to calculate segment coordination variability. Lower extremity joint angles, moments and segment coordination variability were compared between age and sex groups. Significant sex-age interaction effects were found for heel-strike hip flexion and ankle in/eversion angles and peak ankle dorsiflexion angle. In older adults, mid-stance knee flexion angle, ankle inversion and abduction moments and hip abduction and external rotation moments differed by sex. Older compared with younger females had reduced coordination variability in the thigh-shank transverse plane couple but greater coordination variability for the shank rotation-foot eversion couple in early stance. These results suggest there may be a non-equivalent aging process in the movement mechanics for males and females. The age and sex differences in running mechanics and coordination variability highlight the need for sex-based analyses for future studies examining injury risk with age.

  7. The renin-angiotensin system and aging in the kidney.

    Science.gov (United States)

    Yoon, Hye Eun; Choi, Bum Soon

    2014-05-01

    Aging is associated with progressive functional deterioration and structural changes in the kidney. Changes in the activity or responsiveness of the renin-angiotensin system (RAS) occur with aging. RAS changes predispose the elderly to various fluid and electrolyte imbalances as well as acute kidney injury and chronic kidney disease. Among the multiple pathways involved in renal aging, the RAS plays a central role. This review summarizes the association of the RAS with structural and functional changes in the aging kidney and age-related renal injury, and describes the underlying mechanisms of RAS-related renal aging. An improved understanding of the renal aging process may lead to better individualized care of the elderly and improved renal survival in age-related diseases.

  8. Deciphering the Cognitive and Neural Mechanisms Underlying ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Deciphering the Cognitive and Neural Mechanisms Underlying Auditory Learning. This project seeks to understand the brain mechanisms necessary for people to learn to perceive sounds. Neural circuits and learning. The research team will test people with and without musical training to evaluate their capacity to learn ...

  9. Increased skeletal muscle 11βHSD1 mRNA is associated with lower muscle strength in ageing.

    Directory of Open Access Journals (Sweden)

    Alixe H M Kilgour

    Full Text Available Sarcopenia, the loss of muscle mass and function with age, is associated with increased morbidity and mortality. Current understanding of the underlying mechanisms is limited. Glucocorticoids (GC in excess cause muscle weakness and atrophy. We hypothesized that GC may contribute to sarcopenia through elevated circulating levels or increased glucocorticoid receptor (GR signaling by increased expression of either GR or the GC-amplifying enzyme 11 beta-hydroxysteroid dehydrogenase type 1 (11βHSD1 in muscle.There were 82 participants; group 1 comprised 33 older men (mean age 70.2 years, SD 4.4 and 19 younger men (22.2 years, 1.7 and group 2 comprised 16 older men (79.1 years, 3.4 and 14 older women (80.1 years, 3.7. We measured muscle strength, mid-thigh cross-sectional area, fasting morning plasma cortisol, quadriceps muscle GR and 11βHSD1 mRNA, and urinary glucocorticoid metabolites. Data were analysed using multiple linear regression adjusting for age, gender and body size.Muscle strength and size were not associated with plasma cortisol, total urinary glucocorticoids or the ratio of urinary 5β-tetrahydrocortisol +5α-tetrahydrocortisol to tetrahydrocortisone (an index of systemic 11βHSD activity. Muscle strength was associated with 11βHSD1 mRNA levels (β -0.35, p = 0.04, but GR mRNA levels were not significantly associated with muscle strength or size.Although circulating levels of GC are not associated with muscle strength or size in either gender, increased cortisol generation within muscle by 11βHSD1 may contribute to loss of muscle strength with age, a key component of sarcopenia. Inhibition of 11βHSD1 may have therapeutic potential in sarcopenia.

  10. Coexistence of Ureaplasma and chorioamnionitis is associated with prolonged mechanical ventilation.

    Science.gov (United States)

    Jung, Euiseok; Choi, Chang Won; Kim, Su Yeong; Sung, Tae-Jung; Kim, Haeryoung; Park, Kyoung Un; Kim, Han-Suk; Kim, Beyong Il; Choi, Jung-Hwan

    2017-01-01

    Both histologic chorioamnionitis (HCAM) and Ureaplasma infection are considered important contributors to perinatal lung injury. We tested the hypothesis that coexistence of maternal HCAM and perinatal Ureaplasma exposure increases the risk of prolonged mechanical ventilation in extremely low-birthweight (ELBW) infants. A retrospective cohort study was carried out of all ELBW infants born between January 2008 and December 2013 at a single academic center. Placental pathology and gastric fluid Ureaplasma data were available for all infants. Culture and polymerase chain reaction were used to detect Ureaplasma in gastric fluid. Prolonged mechanical ventilation was defined as mechanical ventilation that began within 28 days after birth and continued. Of 111 ELBW infants enrolled, 84 survived beyond 36 weeks of postmenstrual age (PMA) and were included in the analysis. Eighteen infants (21.4%) had both HCAM and Ureaplasma exposure. Seven infants (8.3%) required mechanical ventilation beyond 36 weeks of PMA. Coexistence of HCAM and Ureaplasma in gastric fluid was significantly associated with prolonged mechanical ventilation after adjustment for gestational age, sex, mode of delivery, and use of macrolide antibiotics (OR, 8.7; 95%CI: 1.1-67.2). Coexistence of maternal HCAM and perinatal Ureaplasma exposure significantly increases the risk of prolonged mechanical ventilation in ELBW infants. © 2016 Japan Pediatric Society.

  11. Contraction and elongation: Mechanics underlying cell boundary deformations in epithelial tissue.

    Science.gov (United States)

    Hara, Yusuke

    2017-06-01

    The cell-cell boundaries of epithelial cells form cellular frameworks at the apical side of tissues. Deformations in these boundaries, for example, boundary contraction and elongation, and the associated forces form the mechanical basis of epithelial tissue morphogenesis. In this review, using data from recent Drosophila studies on cell boundary contraction and elongation, I provide an overview of the mechanism underlying the bi-directional deformations in the epithelial cell boundary, that are sustained by biased accumulations of junctional and apico-medial non-muscle myosin II. Moreover, how the junctional tensions exist on cell boundaries in different boundary dynamics and morphologies are discussed. Finally, some future perspectives on how recent knowledge about single cell boundary-level mechanics will contribute to our understanding of epithelial tissue morphogenesis are discussed. © 2017 Japanese Society of Developmental Biologists.

  12. Financial literacy is associated with medial brain region functional connectivity in old age.

    Science.gov (United States)

    Han, S Duke; Boyle, Patricia A; Yu, Lei; Fleischman, Debra A; Arfanakis, Konstantinos; Leurgans, Sue; Bennett, David A

    2014-01-01

    Financial literacy refers to the ability to access and utilize financial information in ways that promote better outcomes. In old age, financial literacy has been associated with a wide range of positive characteristics; however, the neural correlates remain unclear. Recent work has suggested greater co-activity between anterior-posterior medial brain regions is associated with better brain functioning. We hypothesized financial literacy would be associated with this pattern. We assessed whole-brain functional connectivity to a posterior cingulate cortex (PCC) seed region of interest (ROI) in 138 participants of the Rush Memory and Aging Project. Results revealed financial literacy was associated with greater functional connectivity between the PCC and three regions: the right ventromedial prefrontal cortex (vmPFC), the left postcentral gyrus, and the right precuneus. Results also revealed financial literacy was associated negatively with functional connectivity between the PCC and left caudate. Post hoc analyses showed the PCC-vmPFC relationship accounted for the most variance in a regression model adjusted for all four significant functional connectivity relationships, demographic factors, and global cognition. These findings provide information on the neural mechanisms associated with financial literacy in old age. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  13. Age-associated intracellular superoxide dismutase deficiency potentiates dermal fibroblast dysfunction during wound healing.

    Science.gov (United States)

    Fujiwara, Toshihiro; Dohi, Teruyuki; Maan, Zeshaan N; Rustad, Kristine C; Kwon, Sun Hyung; Padmanabhan, Jagannath; Whittam, Alexander J; Suga, Hirotaka; Duscher, Dominik; Rodrigues, Melanie; Gurtner, Geoffrey C

    2017-07-04

    Reactive oxygen species (ROS) impair wound healing through destructive oxidation of intracellular proteins, lipids and nucleic acids. Intracellular superoxide dismutase (SOD1) regulates ROS levels and plays a critical role in tissue homoeostasis. Recent evidence suggests that age-associated wound healing impairments may partially result from decreased SOD1 expression. We investigated the mechanistic basis by which increased oxidative stress links to age-associated impaired wound healing. Fibroblasts were isolated from unwounded skin of young and aged mice, and myofibroblast differentiation was assessed by measuring α-smooth muscle actin and collagen gel contraction. Excisional wounds were created on young and aged mice to study the healing rate, ROS levels and SOD1 expression. A mechanistic link between oxidative stress and fibroblast function was explored by assessing the TGF-β1 signalling pathway components in young and aged mice. Age-related wounds displayed reduced myofibroblast differentiation and delayed wound healing, consistent with a decrease in the in vitro capacity for fibroblast-myofibroblast transition following oxidative stress. Young fibroblasts with normal SOD1 expression exhibited increased phosphorylation of ERK in response to elevated ROS. In contrast, aged fibroblasts with reduced SOD1 expression displayed a reduced capacity to modulate intracellular ROS. Collectively, age-associated wound healing impairments are associated with fibroblast dysfunction that is likely the result of decreased SOD1 expression and subsequent dysregulation of intracellular ROS. Strategies targeting these mechanisms may suggest a new therapeutic approach in the treatment of chronic non-healing wounds in the aged population. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. Gas Bubble Dynamics under Mechanical Vibrations

    Science.gov (United States)

    Mohagheghian, Shahrouz; Elbing, Brian

    2017-11-01

    The scientific community has a limited understanding of the bubble dynamics under mechanical oscillations due to over simplification of Navier-Stockes equation by neglecting the shear stress tensor and not accounting for body forces when calculating the acoustic radiation force. The current work experimental investigates bubble dynamics under mechanical vibration and resulting acoustic field by measuring the bubble size and velocity using high-speed imaging. The experimental setup consists of a custom-designed shaker table, cast acrylic bubble column, compressed air injection manifold and an optical imaging system. The mechanical vibrations resulted in accelerations between 0.25 to 10 times gravitational acceleration corresponding to frequency and amplitude range of 8 - 22Hz and 1 - 10mm respectively. Throughout testing the void fraction was limited to <5%. The bubble size is larger than resonance size and smaller than acoustic wavelength. The amplitude of acoustic pressure wave was estimated using the definition of Bjerknes force in combination with Rayleigh-Plesset equation. Physical behavior of the system was capture and classified. Bubble size, velocity as well as size and spatial distribution will be presented.

  15. Perceived age is associated with bone status in women aged 25-93 years

    DEFF Research Database (Denmark)

    Nielsen, Barbara Rubek; Linneberg, Allan; Christensen, Kaare

    2015-01-01

    ) or "looking young" (LY). Linear mixed models and general linear models fitted with BMD/TBS as outcome and either RPACA or LO/LY as an independent variable, considering chronological age. Estimates of RPACA were all negative; i.e., an increase in RPAC is associated with lower BMD, consistent......Higher perceived age (PA) is reported to be associated with age-related diseases. Because osteoporosis is considered an age-related disease, we hypothesized that age perceived from photographs is associated with bone mineral density (BMD)/trabecular bone score (TBS) when controlled...... for chronological age. This is a cross-sectional study of 460 women aged 25-93 years. BMD/TBS was measured. Twenty physicians assessed age from facial and whole-body photographs. Residual PA (RPACA) was calculated from the regression of PA on chronological age. Participants were divided into "looking old" (LO...

  16. Therapeutic Potential and Recent Advances of Curcumin in the Treatment of Aging-Associated Diseases

    Directory of Open Access Journals (Sweden)

    Sathish Sundar Dhilip Kumar

    2018-04-01

    Full Text Available Curcumin, a low molecular weight, lipophilic, major yellow natural polyphenolic, and the most well-known plant-derived compound, is extracted from the rhizomes of the turmeric (Curcuma longa plant. Curcumin has been demonstrated as an effective therapeutic agent in traditional medicine for the treatment and prevention of different diseases. It has also shown a wide range of biological and pharmacological effects in drug delivery, and has actively been used for the treatment of aging-associated diseases, including cardiovascular diseases, atherosclerosis, neurodegenerative diseases, cancer, rheumatoid arthritis, ocular diseases, osteoporosis, diabetes, hypertension, chronic kidney diseases, chronic inflammation and infection. The functional application and therapeutic potential of curcumin in the treatment of aging-associated diseases is well documented in the literature. This review article focuses mainly on the potential role of plant-derived natural compounds such as curcumin, their mechanism of action and recent advances in the treatment of aging-associated diseases. Moreover, the review briefly recaps on the recent progress made in the preparation of nanocurcumins and their therapeutic potential in clinical research for the treatment of aging-associated diseases.

  17. Therapeutic Potential and Recent Advances of Curcumin in the Treatment of Aging-Associated Diseases.

    Science.gov (United States)

    Sundar Dhilip Kumar, Sathish; Houreld, Nicolette Nadene; Abrahamse, Heidi

    2018-04-05

    Curcumin, a low molecular weight, lipophilic, major yellow natural polyphenolic, and the most well-known plant-derived compound, is extracted from the rhizomes of the turmeric ( Curcuma longa ) plant. Curcumin has been demonstrated as an effective therapeutic agent in traditional medicine for the treatment and prevention of different diseases. It has also shown a wide range of biological and pharmacological effects in drug delivery, and has actively been used for the treatment of aging-associated diseases, including cardiovascular diseases, atherosclerosis, neurodegenerative diseases, cancer, rheumatoid arthritis, ocular diseases, osteoporosis, diabetes, hypertension, chronic kidney diseases, chronic inflammation and infection. The functional application and therapeutic potential of curcumin in the treatment of aging-associated diseases is well documented in the literature. This review article focuses mainly on the potential role of plant-derived natural compounds such as curcumin, their mechanism of action and recent advances in the treatment of aging-associated diseases. Moreover, the review briefly recaps on the recent progress made in the preparation of nanocurcumins and their therapeutic potential in clinical research for the treatment of aging-associated diseases.

  18. Association between physical activity levels and physiological factors underlying mobility in young, middle-aged and older individuals living in a city district.

    Directory of Open Access Journals (Sweden)

    Luca Laudani

    Full Text Available Maintaining adequate levels of physical activity is known to preserve health status and functional independence as individuals grow older. However, the relationship between determinants of physical activity (volume and intensity and physiological factors underlying mobility (cardio-respiratory fitness, neuromuscular function and functional abilities is still unclear. The aim of this study was to investigate the association between objectively quantified physical activity and a spectrum of physiological factors underlying mobility in young, middle-aged and older individuals living in a city district. Experiments were carried out on 24 young (28 ± 2 years, 24 middle-aged (48 ± 2 years and 24 older (70 ± 3 years gender-matched volunteers. Physical activity was monitored by a wearable activity monitor to quantify volume and intensity of overall physical activity and selected habitual activities over 24 hours. Ventilatory threshold was assessed during an incremental cycling test. Torque, muscle fiber conduction velocity and agonist-antagonist coactivation were measured during maximal voluntary contraction of knee extensors and flexors. Ground reaction forces were measured during sit-to-stand and counter-movement jump. K-means cluster analysis was used to classify the participants' physical activity levels based on parameters of volume and intensity. Two clusters of physical activity volume (i.e., high and low volume and three clusters of physical activity intensity (i.e. high, medium and low intensity were identified in all participants. Cardio-respiratory fitness was associated with volume of overall physical activity as well as lying, sitting, standing, walking and stair climbing. On the other hand, neuromuscular function and functional abilities showed a significant association with intensity of overall physical activity as well as postural transition, walking and stair climbing. As a practical application, the relative role played by volume

  19. New insights on molecular mechanisms of renal aging.

    Science.gov (United States)

    Schmitt, R; Melk, A

    2012-11-01

    Long-term transplant outcome is importantly influenced by the age of the organ donor. The mechanisms how age carries out its pathophysiological impact on graft survival are still not understood. One major contributing factor for the observed poor performance of old donor kidneys seems in particular the age-related loss in renal regenerative capacity. In this review, we will summarize recent findings about the molecular basis of renal aging with specific focus on the potential role of somatic cellular senescence and mitochondrial aging in renal transplant outcome. © Copyright 2012 The American Society of Transplantation and the American Society of Transplant Surgeons.

  20. Bone quality changes associated with aging and disease: a review.

    Science.gov (United States)

    Boskey, Adele L; Imbert, Laurianne

    2017-12-01

    Bone quality encompasses all the characteristics of bone that, in addition to density, contribute to its resistance to fracture. In this review, we consider changes in architecture, porosity, and composition, including collagen structure, mineral composition, and crystal size. These factors all are known to vary with tissue and animal ages, and health status. Bone morphology and presence of microcracks, which also contribute to bone quality, will not be discussed in this review. Correlations with mechanical performance for collagen cross-linking, crystallinity, and carbonate content are contrasted with mineral content. Age-dependent changes in humans and rodents are discussed in relation to rodent models of disease. Examples are osteoporosis, osteomalacia, osteogenesis imperfecta (OI), and osteopetrosis in both humans and animal models. Each of these conditions, along with aging, is associated with increased fracture risk for distinct reasons. © 2017 New York Academy of Sciences.

  1. An investigation of the mechanism underlying teacher aggression: Testing I3 theory and the General Aggression Model.

    Science.gov (United States)

    Montuoro, Paul; Mainhard, Tim

    2017-12-01

    Considerable research has investigated the deleterious effects of teachers responding aggressively to students who misbehave, but the mechanism underlying this dysfunctional behaviour remains unknown. This study investigated whether the mechanism underlying teacher aggression follows I 3 theory or General Aggression Model (GAM) metatheory of human aggression. I 3 theory explains exceptional, catastrophic events of human aggression, whereas the GAM explains common human aggression behaviours. A total of 249 Australian teachers participated in this study, including 142 primary school teachers (Mdn [age] = 35-39 years; Mdn [years teaching] = 10-14 years; 84% female) and 107 secondary school teachers (Mdn [age] = 45-49 years; Mdn [years teaching] = 15-19 years; 65% female). Participants completed four online self-report questionnaires, which assessed caregiving responsiveness, trait self-control, misbehaviour provocation, and teacher aggression. Analyses revealed that the GAM most accurately captures the mechanism underlying teacher aggression, with lower caregiving responsiveness appearing to indirectly lead to teacher aggression via higher misbehaviour provocation and lower trait self-control in serial, controlling for gender, age, years teaching, and current role (primary, secondary). This study indicates that teacher aggression proceeds from 'the person in the situation'. Specifically, lower caregiving responsiveness appears to negatively shape a teacher's affective, cognitive, and arousal states, which influence how they perceive and interpret student misbehaviour. These internal states, in turn, appear to negatively influence appraisal and decision processes, leading to immediate appraisal and impulsive actions. These results raise the possibility that teacher aggression is a form of countertransference. © 2017 The British Psychological Society.

  2. Balanced bilingualism and early age of second language acquisition as the underlying mechanisms of a bilingual executive control advantage: why variations in bilingual experiences matter.

    Science.gov (United States)

    Yow, W Quin; Li, Xiaoqian

    2015-01-01

    Recent studies revealed inconsistent evidences of a bilingual advantage in executive processing. One potential source of explanation is the multifaceted experience of the bilinguals in these studies. This study seeks to test whether bilinguals who engage in language selection more frequently would perform better in executive control tasks than those bilinguals who engage in language selection less frequently. We examined the influence of the degree of bilingualism (i.e., language proficiency, frequency of use of two languages, and age of second language acquisition) on executive functioning in bilingual young adults using a comprehensive battery of executive control tasks. Seventy-two 18- to 25-years-old English-Mandarin bilinguals performed four computerized executive function (EF) tasks (Stroop, Eriksen flanker, number-letter switching, and n-back task) that measure the EF components: inhibition, mental-set shifting, and information updating and monitoring. Results from multiple regression analyses, structural equation modeling, and bootstrapping supported the positive association between age of second language acquisition and the interference cost in the Stroop task. Most importantly, we found a significant effect of balanced bilingualism (balanced usage of and balanced proficiency in two languages) on the Stroop and number-letter task (mixing cost only), indicating that a more balanced use and a more balanced level of proficiency in two languages resulted in better executive control skills in the adult bilinguals. We did not find any significant effect of bilingualism on flanker or n-back task. These findings provided important insights to the underlying mechanisms of the bilingual cognitive advantage hypothesis, demonstrating that regular experience with extensive practice in controlling attention to their two language systems results in better performance in related EFs such as inhibiting prepotent responses and global set-shifting.

  3. Balanced bilingualism and early age of second language acquisition as the underlying mechanisms of a bilingual executive control advantage: why variations in bilingual experiences matter

    Science.gov (United States)

    Yow, W. Quin; Li, Xiaoqian

    2015-01-01

    Recent studies revealed inconsistent evidences of a bilingual advantage in executive processing. One potential source of explanation is the multifaceted experience of the bilinguals in these studies. This study seeks to test whether bilinguals who engage in language selection more frequently would perform better in executive control tasks than those bilinguals who engage in language selection less frequently. We examined the influence of the degree of bilingualism (i.e., language proficiency, frequency of use of two languages, and age of second language acquisition) on executive functioning in bilingual young adults using a comprehensive battery of executive control tasks. Seventy-two 18- to 25-years-old English–Mandarin bilinguals performed four computerized executive function (EF) tasks (Stroop, Eriksen flanker, number–letter switching, and n-back task) that measure the EF components: inhibition, mental-set shifting, and information updating and monitoring. Results from multiple regression analyses, structural equation modeling, and bootstrapping supported the positive association between age of second language acquisition and the interference cost in the Stroop task. Most importantly, we found a significant effect of balanced bilingualism (balanced usage of and balanced proficiency in two languages) on the Stroop and number–letter task (mixing cost only), indicating that a more balanced use and a more balanced level of proficiency in two languages resulted in better executive control skills in the adult bilinguals. We did not find any significant effect of bilingualism on flanker or n-back task. These findings provided important insights to the underlying mechanisms of the bilingual cognitive advantage hypothesis, demonstrating that regular experience with extensive practice in controlling attention to their two language systems results in better performance in related EFs such as inhibiting prepotent responses and global set-shifting. PMID:25767451

  4. Balanced bilingualism and early age of second language acquisition as the underlying mechanisms of a bilingual executive control advantage: Why variations in bilingual experiences matter.

    Directory of Open Access Journals (Sweden)

    W. Quin eYow

    2015-02-01

    Full Text Available Recent studies revealed inconsistent evidences of a bilingual advantage in executive processing. One potential source of explanation is the multifaceted experience of the bilinguals in these studies. This study seeks to test whether bilinguals who engage in language selection more frequently would perform better in executive control tasks than those bilinguals who engage in language selection less frequently. We examined the influence of the degree of bilingualism (i.e., language proficiency, frequency of use of two languages, and age of second language acquisition on executive functioning in bilingual young adults using a comprehensive battery of executive control tasks. Seventy-two 18- to 25-year-old English-Mandarin bilinguals performed four computerized executive function tasks (Stroop, Eriksen flanker, number-letter switching and n-back task that measure the executive function components: inhibition, mental-set shifting, and information updating and monitoring. Results from multiple regression analyses, structural equation modeling, and bootstrapping supported the positive association between age of second language acquisition and the interference cost in the Stroop task. Most importantly, we found a significant effect of balanced bilingualism (balanced usage of and balanced proficiency in two languages on the Stroop and number-letter task (mixing cost only, indicating that a more balanced use and a more balanced level of proficiency in two languages resulted in better executive control skills in the adult bilinguals. We did not find any significant effect of bilingualism on flanker or n-back task. These findings provided important insights to the underlying mechanisms of the bilingual cognitive advantage hypothesis, demonstrating that regular experience with extensive practice in controlling attention to their two language systems results in better performance in related executive functions such as inhibiting prepotent responses and global

  5. Ageing in relation to skeletal muscle dysfunction: redox homoeostasis to regulation of gene expression

    OpenAIRE

    Goljanek-Whysall, Katarzyna; Iwanejko, Lesley A.; Vasilaki, Aphrodite; Pekovic-Vaughan, Vanja; McDonagh, Brian

    2016-01-01

    Ageing is associated with a progressive loss of skeletal muscle mass, quality and function?sarcopenia, associated with reduced independence and quality of life in older generations. A better understanding of the mechanisms, both genetic and epigenetic, underlying this process would help develop therapeutic interventions to prevent, slow down or reverse muscle wasting associated with ageing. Currently, exercise is the only known effective intervention to delay the progression of sarcopenia. Th...

  6. Anti-aging effect of adipose-derived stem cells in a mouse model of skin aging induced by D-galactose.

    Directory of Open Access Journals (Sweden)

    Shengchang Zhang

    Full Text Available INTRODUCTION: Glycation products accumulate during aging of slowly renewing tissue, including skin, and are suggested as an important mechanism underlying the skin aging process. Adipose-derived cells are widely used in the clinic to treat ischemic diseases and enhance wound healing. Interestingly, adipose-derived stem cells (ASCs are also effective in anti-aging therapy, although the mechanism underlying their effects remains unknown. The purpose of the present study was to examine the anti-aging effect of ASCs in a D-galactose-induced aging animal model and to clarify the underlying mechanism. MATERIALS AND METHODS: Six-week-old nude mice were subcutaneously injected with D-gal daily for 8 weeks. Two weeks after completion of treatment, mice were randomized to receive subcutaneous injections of 106 green fluorescent protein (GFP-expressing ASCs, aminoguanidine (AG or phosphate-buffered saline (PBS. Control mice received no treatment. We examined tissue histology and determined the activity of senescence-associated molecular markers such as superoxide dismutase (SOD and malondialdehyde (MDA. RESULTS: Transplanted ASCs were detectable for 14 days and their GFP signal disappeared at day 28 after injection. ASCs inhibited advanced glycation end product (AGE levels in our animal model as well as increased the SOD level and decreased the MDA level, all of which act to reverse the aging phenotype in a similar way to AG, an inhibitor of AGE formation. Furthermore, ASCs released angiogenic factors in vivo such as vascular endothelial growth factor, suggesting a skin trophic effect. CONCLUSIONS: These results demonstrate that ASCs may contribute to the regeneration of skin during aging. In addition, the data shows that ASCs provide a functional benefit by glycation suppression, antioxidation, and trophic effects in a mouse model of aging.

  7. Genomic interrogation of mechanism(s) underlying cellular responses to toxicants

    International Nuclear Information System (INIS)

    Amin, Rupesh P.; Hamadeh, Hisham K.; Bushel, Pierre R.; Bennett, Lee; Afshari, Cynthia A.; Paules, Richard S.

    2002-01-01

    Assessment of the impact of xenobiotic exposure on human health and disease progression is complex. Knowledge of mode(s) of action, including mechanism(s) contributing to toxicity and disease progression, is valuable for evaluating compounds. Toxicogenomics, the subdiscipline which merges genomics with toxicology, holds the promise to contributing significantly toward the goal of elucidating mechanism(s) by studying genome-wide effects of xenobiotics. Global gene expression profiling, revolutionized by microarray technology and a crucial aspect of a toxicogenomic study, allows measuring transcriptional modulation of thousands of genes following exposure to a xenobiotic. We use our results from previous studies on compounds representing two different classes of xenobiotics (barbiturate and peroxisome proliferator) to discuss the application of computational approaches for analyzing microarray data to elucidate mechanism(s) underlying cellular responses to toxicants. In particular, our laboratory demonstrated that chemical-specific patterns of gene expression can be revealed using cDNA microarrays. Transcript profiling provides discrimination between classes of toxicants, as well as, genome-wide insight into mechanism(s) of toxicity and disease progression. Ultimately, the expectation is that novel approaches for predicting xenobiotic toxicity in humans will emerge from such information

  8. Vitamin D and parathyroid hormone are associated with gait instability and poor balance performance in mid-age to older aged women.

    Science.gov (United States)

    Bird, Marie-Louise; El Haber, Natalie; Batchelor, Frances; Hill, Keith; Wark, John D

    2018-01-01

    Vitamin D status and parathyroid hormone (PTH) levels influence the risk of accidental falls in older people, but the mechanisms underlying this effect remain unclear. Investigate the relationship between circulating PTH and 25 hydroxyvitamin D (25-OHD) levels and clinical tests of gait stability and balance as physical fall risk factors. We hypothesized that high levels of PTH and low 25-OHD levels would be significantly associated with gait stability and decreased balance performance. Observational cohort study. Australian community. 119 healthy, ambulatory female twin adults aged 47-80 years residing in Victoria, Australia. Serum PTH and 25-OHD levels with clinical tests of gait stability [double support duration (DSD)] and dynamic balance (Step Test). Associations were investigated by regression analysis and by comparing groups divided by tertiles of PTH (4.9pmol/L) and 25-OHD (75 nmol/L) using analysis of variance. Serum PTH was associated positively with DSD, with an increase of 10.6-15.7% when the mid and highest PTH tertiles were compared to the lowest tertile (p <0.025) when 25-OHD was included in the regression analysis. 25-OHD was significantly associated with DSD (greater by 10.6-11.1% when lowest and mid-tertiles compared with the highest 25-OHD tertile) (p <0.025) and dynamic balance (better performance by 12.6% in the highest compared with the lowest 25OHD tertile) (p <0.025). These findings reveal an important new relationship between parathyroid hormone and gait stability parameters and add to understanding of the role of 25-OHD in motor control of gait and dynamic balance in community-dwelling women across a wide age span. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. The association between autism and errors in early embryogenesis: what is the causal mechanism?

    NARCIS (Netherlands)

    Ploeger, A.; Raijmakers, M.E.J.; van der Maas, H.L.J.; Galis, F.

    2010-01-01

    The association between embryonic errors and the development of autism has been recognized in the literature, but the mechanism underlying this association remains unknown. We propose that pleiotropic effects during a very early and specific stage of embryonic development—early organogenesis—can

  10. Association of Central Adiposity With Adverse Cardiac Mechanics: Findings from the HyperGEN Study

    Science.gov (United States)

    Selvaraj, Senthil; Martinez, Eva E.; Aguilar, Frank G.; Kim, Kwang-Youn A.; Peng, Jie; Sha, Jin; Irvin, Marguerite R.; Lewis, Cora E.; Hunt, Steven C.; Arnett, Donna K.; Shah, Sanjiv J.

    2016-01-01

    Background Central obesity, defined by increased waist circumference (WC) or waist-hip ratio (WHR), is associated with increased cardiovascular (CV) events, including heart failure. However, the pathophysiological link between central obesity and adverse CV outcomes remains poorly understood. We hypothesized that central obesity and larger WHR are independently associated with worse cardiac mechanics (reduced left ventricular [LV] strain and systolic [s’] and early diastolic [e’] tissue velocities). Methods and Results We performed speckle-tracking analysis of echocardiograms from participants in the HyperGEN study, a population- and family-based epidemiologic study (N=2181). Multiple indices of systolic and diastolic cardiac mechanics were measured. We evaluated the association between central obesity and cardiac mechanics using multivariable-adjusted linear mixed effects models to account for relatedness among participants. The mean age of the cohort was 51±14 years, 58% were female, and 47% were African-American. Mean body-mass index (BMI) was 30.8±7.1 kg/m2, WC 102±17 cm, WHR 0.91±0.08, and 80% had central obesity based on WC and WHR criteria. After adjusting for multiple potential confounders, including age, sex, race, physical activity, BMI, heart rate, smoking status, systolic blood pressure, fasting glucose, total cholesterol, anti-hypertensive medication use, glomerular filtration rate, LV mass index, wall motion abnormalities, and ejection fraction, central obesity and WHR remained associated with worse global longitudinal strain, early diastolic strain rate, s’ velocity, and e’ velocity (P mechanics. PMID:27307550

  11. Age-associated increase in heterochromatic marks in murine and primate tissues.

    Science.gov (United States)

    Kreiling, Jill A; Tamamori-Adachi, Mimi; Sexton, Alec N; Jeyapalan, Jessie C; Munoz-Najar, Ursula; Peterson, Abigail L; Manivannan, Jayameenakshi; Rogers, Elizabeth S; Pchelintsev, Nikolay A; Adams, Peter D; Sedivy, John M

    2011-04-01

    Chromatin is highly dynamic and subject to extensive remodeling under many physiologic conditions. Changes in chromatin that occur during the aging process are poorly documented and understood in higher organisms, such as mammals. We developed an immunofluorescence assay to quantitatively detect, at the single cell level, changes in the nuclear content of chromatin-associated proteins. We found increased levels of the heterochromatin-associated proteins histone macro H2A (mH2A) and heterochromatin protein 1 beta (HP1β) in human fibroblasts during replicative senescence in culture, and for the first time, an age-associated increase in these heterochromatin marks in several tissues of mice and primates. Mouse lung was characterized by monophasic mH2A expression histograms at both ages, and an increase in mean staining intensity at old age. In the mouse liver, we observed increased age-associated localization of mH2A to regions of pericentromeric heterochromatin. In the skeletal muscle, we found two populations of cells with either low or high mH2A levels. This pattern of expression was similar in mouse and baboon, and showed a clear increase in the proportion of nuclei with high mH2A levels in older animals. The frequencies of cells displaying evidence of increased heterochromatinization are too high to be readily accounted for by replicative or oncogene-induced cellular senescence, and are prominently found in terminally differentiated, postmitotic tissues that are not conventionally thought to be susceptible to senescence. Our findings distinguish specific chromatin states in individual cells of mammalian tissues, and provide a foundation to investigate further the progressive epigenetic changes that occur during aging. © 2010 The Authors. Aging Cell © 2010 Blackwell Publishing Ltd/Anatomical Society of Great Britain and Ireland.

  12. New developments on the neurobiological and pharmaco-genetic mechanisms underlying internet and videogame addiction.

    Science.gov (United States)

    Weinstein, Aviv; Lejoyeux, Michel

    2015-03-01

    There is emerging evidence that the psychobiological mechanisms underlying behavioral addictions such as internet and videogame addiction resemble those of addiction for substances of abuse. Review of brain imaging, treatment and genetic studies on videogame and internet addiction. Literature search of published articles between 2009 and 2013 in Pubmed using "internet addiction" and "videogame addiction" as the search word. Twenty-nine studies have been selected and evaluated under the criteria of brain imaging, treatment, and genetics. Brain imaging studies of the resting state have shown that long-term internet game playing affected brain regions responsible for reward, impulse control and sensory-motor coordination. Brain activation studies have shown that videogame playing involved changes in reward and loss of control and that gaming pictures have activated regions similarly to those activated by cue-exposure to drugs. Structural studies have shown alterations in the volume of the ventral striatum possible as result of changes in reward. Furthermore, videogame playing was associated with dopamine release similar in magnitude to those of drugs of abuse and that there were faulty inhibitory control and reward mechanisms videogame addicted individuals. Finally, treatment studies using fMRI have shown reduction in craving for videogames and reduced associated brain activity. Videogame playing may be supported by similar neural mechanisms underlying drug abuse. Similar to drug and alcohol abuse, internet addiction results in sub-sensitivity of dopamine reward mechanisms. Given the fact that this research is in its early stage it is premature to conclude that internet addiction is equivalent to substance addictions. © American Academy of Addiction Psychiatry.

  13. micro-mechanical experimental investigation and modelling of strain and damage of argillaceous rocks under combined hydric and mechanical loads

    International Nuclear Information System (INIS)

    Wang, L.

    2012-01-01

    The hydro-mechanical behavior of argillaceous rocks, which are possible host rocks for underground radioactive nuclear waste storage, is investigated by means of micro-mechanical experimental investigations and modellings. Strain fields at the micrometric scale of the composite structure of this rock, are measured by the combination of environmental scanning electron microscopy, in situ testing and digital image correlation technique. The evolution of argillaceous rocks under pure hydric loading is first investigated. The strain field is strongly heterogeneous and manifests anisotropy. The observed nonlinear deformation at high relative humidity (RH) is related not only to damage, but also to the nonlinear swelling of the clay mineral itself, controlled by different local mechanisms depending on RH. Irreversible deformations are observed during hydric cycles, as well as a network of microcracks located in the bulk of the clay matrix and/or at the inclusion-matrix interface. Second, the local deformation field of the material under combined hydric and mechanical loadings is quantified. Three types of deformation bands are evidenced under mechanical loading, either normal to stress direction (compaction), parallel (microcracking) or inclined (shear). Moreover, they are strongly controlled by the water content of the material: shear bands are in particular prone to appear at high RH states. In view of understanding the mechanical interactions a local scale, the material is modeled as a composite made of non-swelling elastic inclusions embedded in an elastic swelling clay matrix. The internal stress field induced by swelling strain incompatibilities between inclusions and matrix, as well as the overall deformation, is numerically computed at equilibrium but also during the transient stage associated with a moisture gradient. An analytical micro-mechanical model based on Eshelby's solution is proposed. In addition, 2D finite element computations are performed. Results

  14. Blood DNA methylation age is not associated with cognitive functioning in middle-aged monozygotic twins

    DEFF Research Database (Denmark)

    Starnawska, A; Tan, Q; Lenart, A

    2016-01-01

    The epigenetic clock, also known as DNA methylation age (DNAmAge), represents age-related changes of DNA methylation at multiple sites of the genome and is suggested to be a biomarker for biological age. Elevated blood DNAmAge is associated with all-cause mortality, with the strongest effects...... reported in a recent intrapair twin study where epigenetically older twins had increased mortality risk in comparison to their co-twins. In the study presented here, we hypothesize that DNAmAge in blood is associated with cross-sectional and longitudinal cognitive abilities in middle-aged individuals....... In 486 monozygotic twins, we investigated the association of DNAmAge, difference between DNAmAge and chronological age and age acceleration with cognition. Despite using a powerful paired twin design, we found no evidence for association of blood DNAmAge with cognitive abilities. This observation...

  15. Problems associated with accelerated thermal aging of electrical equipment

    International Nuclear Information System (INIS)

    Isgro, J.R.

    1984-01-01

    This paper discusses the potential problems that may be experienced when accounting for aging mechanisms in organic polymers when utilizing accelerated thermal aging techniques for electrical equipment qualification. Included are discussions of actual experiences and problems encountered in the qualification of electrical and electronic equipment for a complete nuclear power plant. The wide variety of approaches to thermal accelerated aging by various manufacturers of diverse equipment types provides depth to the discussion. A description of how to account for aging mechanisms is also presented

  16. Basic science and pathogenesis of ageing with HIV: potential mechanisms and biomarkers.

    Science.gov (United States)

    Lagathu, Claire; Cossarizza, Andrea; Béréziat, Véronique; Nasi, Milena; Capeau, Jacqueline; Pinti, Marcello

    2017-06-01

    : The increased prevalence of age-related comorbidities and mortality is worrisome in ageing HIV-infected patients. Here, we aim to analyse the different ageing mechanisms with regard to HIV infection. Ageing results from the time-dependent accumulation of random cellular damage. Epigenetic modifications and mitochondrial DNA haplogroups modulate ageing. In antiretroviral treatment-controlled patients, epigenetic clock appears to be advanced, and some haplogroups are associated with HIV infection severity. Telomere shortening is enhanced in HIV-infected patients because of HIV and some nucleoside analogue reverse transcriptase inhibitors. Mitochondria-related oxidative stress and mitochondrial DNA mutations are increased during ageing and also by some nucleoside analogue reverse transcriptase inhibitors. Overall, increased inflammation or 'inflammageing' is a major driver of ageing and could result from cell senescence with secreted proinflammatory mediators, altered gut microbiota, and coinfections. In HIV-infected patients, the level of inflammation and innate immunity activation is enhanced and related to most comorbidities and to mortality. This status could result, in addition to age, from the virus itself or viral protein released from reservoirs, from HIV-enhanced gut permeability and dysbiosis, from antiretroviral treatment, from frequent cytomegalovirus and hepatitis C virus coinfections, and also from personal and environmental factors, as central fat accumulation or smoking. Adaptive immune activation and immunosenescence are associated with comorbidities and mortality in the general population but are less predictive in HIV-infected patients. Biomarkers to evaluate ageing in HIV-infected patients are required. Numerous systemic or cellular inflammatory, immune activation, oxidative stress, or senescence markers can be tested in serum or peripheral blood mononuclear cells. The novel European Study to Establish Biomarkers of Human Ageing MARK-AGE

  17. Bioactive silica nanoparticles reverse age-associated bone loss in mice.

    Science.gov (United States)

    Weitzmann, M Neale; Ha, Shin-Woo; Vikulina, Tatyana; Roser-Page, Susanne; Lee, Jin-Kyu; Beck, George R

    2015-05-01

    We recently reported that in vitro, engineered 50nm spherical silica nanoparticles promote the differentiation and activity of bone building osteoblasts but suppress bone-resorbing osteoclasts. Furthermore, these nanoparticles promote bone accretion in young mice in vivo. We have now investigated the capacity of these nanoparticles to reverse bone loss in aged mice, a model of human senile osteoporosis. Aged mice received nanoparticles weekly and bone mineral density (BMD), bone structure, and bone turnover were quantified. Our data revealed a significant increase in BMD, bone volume, and biochemical markers of bone formation. Biochemical and histological examinations failed to identify any abnormalities caused by nanoparticle administration. Our studies demonstrate that silica nanoparticles effectively blunt and reverse age-associated bone loss in mice by a mechanism involving promotion of bone formation. The data suggest that osteogenic silica nanoparticles may be a safe and effective therapeutic for counteracting age-associated bone loss. Osteoporosis poses a significant problem in the society. Based on their previous in-vitro findings, the authors' group investigated the effects of spherical silica nanoparticles in reversing bone loss in a mouse model of osteoporosis. The results showed that intra-peritoneal injections of silica nanoparticles could increase bone mineral density, with little observed toxic side effects. This novel method may prove important in future therapy for combating osteoporosis. Published by Elsevier Inc.

  18. A genome-wide association study implicates the APOE locus in nonpathological cognitive ageing.

    Science.gov (United States)

    Davies, G; Harris, S E; Reynolds, C A; Payton, A; Knight, H M; Liewald, D C; Lopez, L M; Luciano, M; Gow, A J; Corley, J; Henderson, R; Murray, C; Pattie, A; Fox, H C; Redmond, P; Lutz, M W; Chiba-Falek, O; Linnertz, C; Saith, S; Haggarty, P; McNeill, G; Ke, X; Ollier, W; Horan, M; Roses, A D; Ponting, C P; Porteous, D J; Tenesa, A; Pickles, A; Starr, J M; Whalley, L J; Pedersen, N L; Pendleton, N; Visscher, P M; Deary, I J

    2014-01-01

    Cognitive decline is a feared aspect of growing old. It is a major contributor to lower quality of life and loss of independence in old age. We investigated the genetic contribution to individual differences in nonpathological cognitive ageing in five cohorts of older adults. We undertook a genome-wide association analysis using 549 692 single-nucleotide polymorphisms (SNPs) in 3511 unrelated adults in the Cognitive Ageing Genetics in England and Scotland (CAGES) project. These individuals have detailed longitudinal cognitive data from which phenotypes measuring each individual's cognitive changes were constructed. One SNP--rs2075650, located in TOMM40 (translocase of the outer mitochondrial membrane 40 homolog)--had a genome-wide significant association with cognitive ageing (P=2.5 × 10(-8)). This result was replicated in a meta-analysis of three independent Swedish cohorts (P=2.41 × 10(-6)). An Apolipoprotein E (APOE) haplotype (adjacent to TOMM40), previously associated with cognitive ageing, had a significant effect on cognitive ageing in the CAGES sample (P=2.18 × 10(-8); females, P=1.66 × 10(-11); males, P=0.01). Fine SNP mapping of the TOMM40/APOE region identified both APOE (rs429358; P=3.66 × 10(-11)) and TOMM40 (rs11556505; P=2.45 × 10(-8)) as loci that were associated with cognitive ageing. Imputation and conditional analyses in the discovery and replication cohorts strongly suggest that this effect is due to APOE (rs429358). Functional genomic analysis indicated that SNPs in the TOMM40/APOE region have a functional, regulatory non-protein-coding effect. The APOE region is significantly associated with nonpathological cognitive ageing. The identity and mechanism of one or multiple causal variants remain unclear.

  19. Prospective association of TV viewing with acute phase reactants and coagulation markers: English Longitudinal Study of Ageing.

    Science.gov (United States)

    Hamer, Mark; Smith, Lee; Stamatakis, Emmanuel

    2015-04-01

    Inflammatory processes are putative mechanisms underlying the detrimental health effects of sedentary behaviour but no long-term prospective data are available. We examined the longitudinal association between TV viewing, physical activity and inflammatory markers over a 4-year follow-up period. Participants were 3612 men and women (mean age 64.1 ± 8.2 years) from the English Longitudinal Study of Ageing. Self-reported daily TV viewing was measured at baseline and 2 years follow up. Inflammatory markers (serum high-sensitivity C-reactive protein [CRP], white blood cell count [WBC], and fibrinogen) were measured at baseline (2008/09) and 4 years follow-up (2012/13). On average, participants viewed TV for 5.1 ± 4.0 h/d, and there was an increase of 1.9 h/wk TV viewing over 2 years. In linear models adjusted for covariates including physical activity, TV viewing was not associated with logeCRP at follow-up (B = 0.004, 95% CI, -0.001, 0.009, p = 0.09) but was associated with WBC (B = 0.018, 95% CI, 0.005, 0.031, p = 0.006), and fibrinogen (B = 0.004, 95% CI, 0.00, 0.008, p = 0.035). In contrast, physical activity was inversely associated with CRP (p = 0.047) and WBC (p = 0.026), but not fibrinogen (p = 0.22). An increase in TV viewing (of at least 1 h/d) was associated with higher concentrations of CRP (p = 0.015) and WBC (p = 0.05) at follow up after adjustment for covariates and baseline TV viewing. Physical activity and sedentary behaviour have contrasting associations with markers of low grade inflammation over 4 years of follow-up. These behaviours may be important in influencing the pro-inflammatory state seen with ageing. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  20. Mechanical and morphological properties of different muscle-tendon units in the lower extremity and running mechanics: effect of aging and physical activity.

    Science.gov (United States)

    Karamanidis, Kiros; Arampatzis, Adamantios

    2005-10-01

    The objectives of this work were (i) to investigate whether chronic endurance running is a sufficient stimulus to counteract the age-related changes in the mechanical and morphological properties of human triceps surae (TS) and quadriceps femoris (QF) muscle-tendon units (MTUs) by comparing runners and non-active subjects at different ages (young and old), (ii) to identify adaptational phenomena in running mechanics due to age-related changes in the mechanical and morphological properties of the TS and QF MTUs, and finally (iii) to examine whether chronic endurance-running exercise is associated with adaptational effects on running characteristics in old and young adults. The investigation was conducted on 30 old and 19 young adult males divided into two subgroups according to their running activity: endurance-runners vs non-active. To analyse the properties of the MTUs, all subjects performed isometric maximal voluntary (MVC) ankle plantarflexion and knee extension contractions at 11 different MTU lengths on a dynamometer. The activation of the TS and QF during MVC was estimated by surface electromyography. The gastrocnemius medialis and the vastus lateralis and their distal aponeuroses were visualized by ultrasonography at rest and during MVC, respectively. Ground reaction forces and kinematic data were recorded during running trials at 2.7 m s(-1). The TS and QF MTU capacities were reduced with aging (lower muscle strength and lower tendon stiffness). Runners and non-active subjects had similar MTU properties, suggesting that chronic endurance-running exercise does not counteract the age-related degeneration of the MTUs. Runners showed a higher mechanical advantage for the QF MTU while running (lower gear ratio) compared to non-active subjects, indicating a task-specific adaptation even at old age. Older adults reacted to the reduced capacities of their MTUs by increasing running safety (higher duty factor, lower flight time) and benefitting from a mechanical

  1. Delayed and accelerated aging share common longevity assurance mechanisms

    NARCIS (Netherlands)

    Schumacher, B.; van der Pluijm, I.; Moorhouse, M.J.; Kosteas, T.; Robinson, A.R.; Suh, Y.; Breit, T.M.; van Steeg, H.; Niedernhofer, L.J.; van IJcken, W.; Bartke, A.; Spindler, S.R.; Hoeijmakers, J.H.J.; van der Horst, G.T.J.; Garinis, G.A.

    2008-01-01

    Mutant dwarf and calorie-restricted mice benefit from healthy aging and unusually long lifespan. In contrast, mouse models for DNA repair-deficient progeroid syndromes age and die prematurely. To identify mechanisms that regulate mammalian longevity, we quantified the parallels between the

  2. Delayed and accelerated aging share common longevity assurance mechanisms

    NARCIS (Netherlands)

    B. Schumacher (Björn); I. van der Pluijm (Ingrid); M.J. Moorhouse (Michael); T. Kosteas (Theodore); A.R. Robinson (Andria Rasile); Y. Suh (Yousin); T.M. Breit (Timo); H. van Steeg (Harry); L.J. Niedernhofer (Laura); W.F.J. van IJcken (Wilfred); A. Bartke (Andrzej); S.R. Spindler (Stephen); J.H.J. Hoeijmakers (Jan); G.T.J. van der Horst (Gijsbertus); G.A. Garinis (George)

    2008-01-01

    textabstractMutant dwarf and calorie-restricted mice benefit from healthy aging and unusually long lifespan. In contrast, mouse models for DNA repair-deficient progeroid syndromes age and die prematurely. To identify mechanisms that regulate mammalian longevity, we quantified the parallels between

  3. Suicide rates: age-associated trends and their correlates

    Directory of Open Access Journals (Sweden)

    Ajit Shah

    2012-07-01

    Full Text Available BACKGROUND: Suicide rates traditionally increased with ageing. There is a paucity of studies examining factors associated with age-associated trends in suicide rates. METHODS: The relationship between suicide rates and ageing was examined by ascertaining suicide rates in the seven age-bands 16-24 years to 75+ years from the World Health Organization for 97 countries. The relationship between socio-economic status, income inequality, healthcare expenditure, child mortality rates and life expectancy and countries with an increase, a decline and no change in suicide rates with ageing was examined using data from the United Nations. RESULTS: In males and females there was a decline in 5 and 10 countries, an increase in 33 and 37 countries and no change in 59 and 50 countries respectively in suicide rates with ageing. Age-associated trends in suicide rates were significantly associated with socio-economic status (males or income inequality (females, per capita expenditure in healthcare, the proportion of gross-national domestic product spent on healthcare, child mortality rates and life expectancy. CONCLUSIONS: The current study, of factors associated with age-associated trends in suicide rates, confirmed a previously developed five sequential stage model to explain the relationship between elderly suicide rates and socio-economic status and income inequality, quality and quantity of healthcare services, child mortality rates and life expectancy.

  4. Interplay between mast cells, enterochromaffin cells, and sensory signaling in the aging human bowel.

    Science.gov (United States)

    Yu, Y; Daly, D M; Adam, I J; Kitsanta, P; Hill, C J; Wild, J; Shorthouse, A; Grundy, D; Jiang, W

    2016-10-01

    Advanced age is associated with a reduction in clinical visceral pain perception. However, the underlying mechanisms remain largely unknown. Previous studies have suggested that an abnormal interplay between mast cells, enterochromaffin (EC) cells, and afferent nerves contribute to nociception in gastrointestinal disorders. The aim of this study was to investigate how aging affects afferent sensitivity and neuro-immune association in the human bowel. Mechanical and chemical sensitivity of human bowel afferents were examined by ex vivo afferent nerve recordings. Age-related changes in the density of mast cells, EC cells, sensory nerve terminals, and mast cell-nerve micro-anatomical association were investigated by histological and immune staining. Human afferents could be broadly classified into subpopulations displaying mechanical and chemical sensitivity, adaptation, chemo-sensitization, and recruitment. Interestingly human bowel afferent nerve sensitivity was attenuated with age. The density of substance P-immunoreactive (SP-IR) nerve varicosities was also reduced with age. In contrast, the density of ileal and colonic mucosal mast cells was increased with age, as was ileal EC cell number. An increased proportion of mast cells was found in close apposition to SP-IR nerves. Afferent sensitivity in human bowel was reduced with advancing age. Augmentation of mast cells and EC cell numbers and the mast cell-nerve association suggest a compensatory mechanism for sensory neurodegeneration. © 2016 The Authors. Neurogastroenterology & Motility Published by John Wiley & Sons Ltd.

  5. Guarantee of remaining life time. Integrity of mechanical components and control of ageing phenomena

    International Nuclear Information System (INIS)

    Schuler, X.; Herter, K.H.; Koenig, G.

    2012-01-01

    The life time of safety relevant systems, structures and components (SSC) of Nuclear Power Plants (NPP) is determined by two main principles. First of all the required quality has to be produced during the design and fabrication process. This means that quality has to be produced and can't be improved by excessive inspections (Basis Safety - quality through production principle). The second one is assigned to the initial quality which has to be maintained during operation. This concerns safe operation during the total life time (life time management), safety against ageing phenomena (AM - ageing management) as well as proof of integrity (e.g. break preclusion or avoidance of fracture for SSC with high safety relevance). Initiated by the Fukushima Dai-ichi event in Japan in spring 2011 for German NPP's Long Term Operation (LTO) is out of question. In June 2011 legislation took decision to phase-out from nuclear by 2022. As a fact safe operation shall be guaranteed for the remaining life time. Within this technical framework the ageing management is a key element. Depending on the safety-relevance of the SSC under observation including preventive maintenance various tasks are required in particular to clarify the mechanisms which contribute systemspecifically to the damage of the components and systems and to define their controlling parameters which have to be monitored and checked. Appropriate continuous or discontinuous measures are to be considered in this connection. The approach to ensure a high standard of quality in operation for the remaining life time and the management of the technical and organizational aspects are demonstrated and explained. The basis for ageing management to be applied to NNPs is included in Nuclear Safety Standard 1403 which describes the ageing management procedures. For SSC with high safety relevance a verification analysis for rupture preclusion (proof of integrity, integrity concept) shall be performed (Nuclear Safety Standard 3206

  6. Behavior of duplex stainless steel casting defects under mechanical loadings

    International Nuclear Information System (INIS)

    Jayet-Gendrot, S.; Gilles, P.

    2000-01-01

    Several components in the primary circuit of pressurized water reactors are made of cast duplex stainless steels. This material contains small casting defects, mainly shrinkage cavities, due to the manufacturing process. In safety analyses, the structural integrity of the components is studied under the most severe assumptions: presence of a large defect, accidental loadings and end-of-life material properties accounting for its thermal aging embrittlement at the service temperature. The casting defects are idealized as semi-circular surface cracks or notches that have envelope dimensions. In order to assess the real severity of the casting defects under mechanical loadings, an experimental program was carried out. It consisted of testing, under both cyclic and monotonic solicitations, three-point bend specimens containing either a natural defect (in the form of a localized cluster of cavities) or a machined notch having the dimensions of the cluster's envelope. The results show that shrinkage cavities are far less harmful than envelope notches thanks to the metal bridges between cavities. Under fatigue loadings, the generalized initiation of a cluster of cavities (defined when the cluster becomes a crack of the same global size) is reached for a number of cycles that is much higher than the one leading to the initiation of a notch. In the case of monotonic loadings, specimens with casting defects offer a very high resistance to ductile tearing. The tests are analyzed in order to develop a method that takes into account the behavior of casting defects in a more realistic fashion than by an envelope crack. Various approaches are investigated, including the search of equivalent defects or of criteria based on continuum mechanics concepts, and compared with literature data. This study shows the conservatism of current safety analyses in modeling casting defects by envelope semi-elliptical cracks and contributes to the development of alternative approaches. (orig.)

  7. Longitudinal associations between social relationships at age 30 and internalising symptoms at age 42: findings from the Northern Swedish Cohort.

    Science.gov (United States)

    Landstedt, Evelina; Gustafsson, Per E; Johansson, Klara; Hammarström, Anne

    2016-01-01

    Little is known on long-term consequences of poor social relationships in adulthood. The study aimed to examine associations between social relationships at age 30 and internalising symptoms at age 42. Data was drawn from four waves of the Northern Swedish cohort (n = 1001, 94 % response rate). The outcome internalising symptoms was measured by a composite index of depressiveness and anxiety. A cumulative measure was constructed to reflect various aspects of social relationships. Multivariate ordinal logistic regressions were used, controlling for socioeconomic indicators and previous level of internalising symptoms. An accumulation of poor social relationships indicators at age 30 is related to internalising symptoms at age 42 in women (OR 1.30; CI 1.11-1.52) and men (OR 1.17; CI 1.02-1.36). The associations remained significant after adjustment for covariates. Poor quality of social relationships at age 30 can predict internalising symptoms 12 years later in both men and women even when previous mental health as well as financial disadvantage is accounted for. More research is required to further examine pathways and mechanisms as well as suitable interventions.

  8. Investigation on thermal oxidative aging of nitrile rubber (NBR) O-rings under compression stress

    Science.gov (United States)

    Liu, X. R.; Zhang, W. F.; Lou, W. T.; Huang, Y. X.; Dai, W.

    2017-11-01

    The degradation behaviors of nitrile rubber O-rings exposure to air under compression were investigated at three elevated temperatures. The physical and mechanical properties of the aging samples before and after exposure at selected time were studied by measuring weight loss, tensile strength and elongation at break. The Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and fracture morphology were used to reveal the microstructural changes of the aging samples. The results indicate that the weight decreased with exposure time and temperature. Based on the results of the crosslinking density, the crosslinking predominates during the most of aging process. The significant changes in tensile strength and elongation at break also indicate the severe degradation in air. The fracture morphology results show that the fracture surface after 64 days of exposure to air turns rough and present defects. The ATR-FTIR results demonstrate that the hydroxyl groups were formed for the samples aged in air.

  9. Age-associated sperm DNA methylation alterations: possible implications in offspring disease susceptibility.

    Science.gov (United States)

    Jenkins, Timothy G; Aston, Kenneth I; Pflueger, Christian; Cairns, Bradley R; Carrell, Douglas T

    2014-07-01

    Recent evidence demonstrates a role for paternal aging on offspring disease susceptibility. It is well established that various neuropsychiatric disorders (schizophrenia, autism, etc.), trinucleotide expansion associated diseases (myotonic dystrophy, Huntington's, etc.) and even some forms of cancer have increased incidence in the offspring of older fathers. Despite strong epidemiological evidence that these alterations are more common in offspring sired by older fathers, in most cases the mechanisms that drive these processes are unclear. However, it is commonly believed that epigenetics, and specifically DNA methylation alterations, likely play a role. In this study we have investigated the impact of aging on DNA methylation in mature human sperm. Using a methylation array approach we evaluated changes to sperm DNA methylation patterns in 17 fertile donors by comparing the sperm methylome of 2 samples collected from each individual 9-19 years apart. With this design we have identified 139 regions that are significantly and consistently hypomethylated with age and 8 regions that are significantly hypermethylated with age. A representative subset of these alterations have been confirmed in an independent cohort. A total of 117 genes are associated with these regions of methylation alterations (promoter or gene body). Intriguingly, a portion of the age-related changes in sperm DNA methylation are located at genes previously associated with schizophrenia and bipolar disorder. While our data does not establish a causative relationship, it does raise the possibility that the age-associated methylation of the candidate genes that we observe in sperm might contribute to the increased incidence of neuropsychiatric and other disorders in the offspring of older males. However, further study is required to determine whether, and to what extent, a causative relationship exists.

  10. Age-Related Decrease in Heat Shock 70-kDa Protein 8 in Cerebrospinal Fluid Is Associated with Increased Oxidative Stress.

    Science.gov (United States)

    Loeffler, David A; Klaver, Andrea C; Coffey, Mary P; Aasly, Jan O; LeWitt, Peter A

    2016-01-01

    Age-associated declines in protein homeostasis mechanisms ("proteostasis") are thought to contribute to age-related neurodegenerative disorders. The increased oxidative stress which occurs with aging can activate a key proteostatic process, chaperone-mediated autophagy. This study investigated age-related alteration in cerebrospinal fluid (CSF) concentrations of heat shock 70-kDa protein 8 (HSPA8), a molecular chaperone involved in proteostatic mechanisms including chaperone-mediated autophagy, and its associations with indicators of oxidative stress (8-hydroxy-2'-deoxyguanosine [8-OHdG] and 8-isoprostane) and total anti-oxidant capacity. We examined correlations between age, HSPA8, 8-OHdG, 8-isoprostane, and total antioxidant capacity (TAC) in CSF samples from 34 healthy subjects ranging from 20 to 75 years of age. Age was negatively associated with HSPA8 (ρ = -0.47; p = 0.005). An age-related increase in oxidative stress was indicated by a positive association between age and 8-OHdG (ρ = 0.61; p = 0.0001). HSPA8 was moderately negatively associated with 8-OHdG (ρ = -0.58; p = 0.0004). Age and HSPA8 were weakly associated with 8-isoprostane and TAC (range of ρ values: -0.15 to 0.16). Our findings in this exploratory study suggest that during healthy aging, CSF HSPA8 may decrease, perhaps due in part to an increase in oxidative stress. Our results also suggest that 8-OHdG may be more sensitive than 8-isoprostane for measuring oxidative stress in CSF. Further studies are indicated to determine if our findings can be replicated with a larger cohort, and if the age-related decrease in HSPA8 in CSF is reflected by a similar change in the brain.

  11. Microstructures and mechanical properties of age-formed 7050 aluminum alloy

    International Nuclear Information System (INIS)

    Chen, J.F.; Zhen, L.; Jiang, J.T.; Yang, L.; Shao, W.Z.; Zhang, B.Y.

    2012-01-01

    Highlights: ► Age-forming leads to the grain elongation in 7050 alloy. ► Age-forming varies the texture components in 7050 alloy. ► Age-forming promotes precipitates growth and PFZ enlargement in 7050 alloy. ► Age-forming induces to descend apparently elongation in 7050 alloy. ► The effect of age-forming on microstructure and properties is discussed in-depth. - Abstract: The effects of age-forming on microstructures and mechanical properties of 7050 Al alloy were investigated in this work. The alloy was subjected to age-forming as well as stress-free ageing at 160 °C for 6, 12, 18 and 24 h, and its microstructures were characterized by electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). It was shown that creep might lead to grain elongation during age-forming, and the applied stress induces the coarsening of precipitates in 7050 Al alloy. The texture in the alloy was also influenced by age-forming. Consequently, the differences in microstructures result in differences in mechanical properties of age-forming versus traditional stress-free ageing. The ultimate tensile strength of age-formed samples were slightly lower than that of stress-free aged samples, while the yield strength of age-formed samples were apparently lower than that of stress-free aged samples. Specifically, the elongation of samples age-formed displays apparently decrease.

  12. Oxidation assisted intergranular cracking under loading at dynamic strain aging temperatures in Inconel 718 superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Rezende, M.C., E-mail: monica_crezende@hotmail.com [Universidade Federal do Rio de Janeiro, Departamento de Engenharia Metalúrgica e de Materiais, C.P. 68505, Rio de Janeiro 21945-970 (Brazil); Araújo, L.S.; Gabriel, S.B. [Universidade Federal do Rio de Janeiro, Departamento de Engenharia Metalúrgica e de Materiais, C.P. 68505, Rio de Janeiro 21945-970 (Brazil); Dille, J. [Université Libre de Bruxelles, 4MAT Department, Av. F. Roosevelt 50, C.P. 194/03, Brussels (Belgium); Almeida, L.H. de [Universidade Federal do Rio de Janeiro, Departamento de Engenharia Metalúrgica e de Materiais, C.P. 68505, Rio de Janeiro 21945-970 (Brazil)

    2015-09-15

    Highlights: • Mechanical properties are controlled by DSA, precipitation hardening and OAIC. • Between 600 and 700 °C the critical strain for serrations increases with temperature. • This is related to the consumption of matrix elements (especially Nb: for γ′ and γ″). • A reduction in ductility occurs (related to the OAIC) when the DSA is no longer effective. • This reduction is accompanied by an increase in intergranular brittle fracture. - Abstract: It is well established that 718 superalloy exhibits brittle intergranular cracking when deformed under tension at temperatures above 600 °C. This embrittlement effect is related with grain boundary penetration by oxygen (Oxygen Assisted Intergranular Cracking – OAIC). Simultaneously, impacting on its mechanical properties, the precipitation of coherent γ′ and γ″ phases occur above 650 °C and Dynamic Strain Aging (DSA) occurs in the temperature range between 200 and 800 °C. Although literature indicates that OAIC is the mechanism that controls mechanical properties at high temperatures, its interactions with DSA and precipitation are still under discussion. The objective of this work is to investigate the interactions between the embrittlement phenomena (OAIC and DSA) and the hardening mechanism of γ′ and γ″ precipitation on the mechanical properties of an annealed 718 superalloy. Tensile tests were performed at a strain rate of 3.2 × 10{sup −4} s{sup −1} under secondary vacuum, in temperatures ranging from 200 to 800 °C. Fracture surfaces were observed by scanning electron microscopy (SEM) and precipitation by transmission electron microscopy (TEM). The effect of DSA and precipitation on the strength and of OAIC on the ductility was verified.

  13. Vitamins Associated with Brain Aging, Mild Cognitive Impairment, and Alzheimer Disease: Biomarkers, Epidemiological and Experimental Evidence, Plausible Mechanisms, and Knowledge Gaps.

    Science.gov (United States)

    Fenech, Michael

    2017-11-01

    The key to preventing brain aging, mild cognitive impairment (MCI), and Alzheimer disease (AD) via vitamin intake is first to understand molecular mechanisms, then to deduce relevant biomarkers, and subsequently to test the level of evidence for the impact of vitamins in the relevant pathways and their modulation of dementia risk. This narrative review infers information on mechanisms from gene and metabolic defects associated with MCI and AD, and assesses the role of vitamins using recent results from animal and human studies. Current evidence suggests that all known vitamins and some "quasi-vitamins" are involved as cofactors or influence ≥1 of the 6 key sets of pathways or pathologies associated with MCI or AD, relating to 1 ) 1-carbon metabolism, 2 ) DNA damage and repair, 3 ) mitochondrial function and glucose metabolism, 4 ) lipid and phospholipid metabolism and myelination, 5 ) neurotransmitter synthesis and synaptogenesis, and 6 ) amyloidosis and Tau protein phosphorylation. The contemporary level of evidence for each of the vitamins varies considerably, but it is notable that B vitamins are involved as cofactors in all of the core pathways or pathologies and, together with vitamins C and E, are consistently associated with a protective role against dementia. Outcomes from recent studies indicate that the efficacy and safety of supplementation with vitamins to prevent MCI and the early stages of AD will most likely depend on 1 ) which pathways are defective, 2 ) which vitamins are deficient and could correct the relevant metabolic defects, and 3 ) the modulating impact of nutrient-nutrient and nutrient-genotype interaction. More focus on a precision nutrition approach is required to realize the full potential of vitamin therapy in preventing dementia and to avoid causing harm. © 2017 American Society for Nutrition.

  14. Factors Associated with Postoperative Prolonged Mechanical Ventilation in Pediatric Liver Transplant Recipients

    Directory of Open Access Journals (Sweden)

    Olubukola O. Nafiu

    2017-01-01

    Full Text Available Introduction. Almost all pediatric orthotopic liver transplant (OLT recipients require mechanical ventilation in the early postoperative period. Prolonged postoperative mechanical ventilation (PPMV may be a marker of severe disease and may be associated with morbidity and mortality. We determined the incidence and risk factors for PPMV in children who underwent OLT. Methods. This was a retrospective analysis of data collected on 128 pediatric OLT recipients. PPMV was defined as postoperative ventilation ≥ 4 days. Perioperative characteristics were compared between cases and control groups. Multivariable logistic regression analysis was used to calculate odds ratios for PPMV after controlling for relevant cofactors. Results. An estimated 25% (95% CI, 17.4%–32.6% required PPMV. The overall incidence of PPMV varied significantly by age group with the highest incidence among infants. PPMV was associated with higher postoperative mortality (p=0.004 and longer intensive care unit (p<0.001 and hospital length of stay (p<0.001. Multivariable analysis identified young patient age, preoperative hypocalcemia, and increasing duration of surgery as independent predictors of PPMV following OLT. Conclusion. The incidence of PPMV is high and it was associated with prolonged ICU and hospital LOS and higher posttransplant mortality. Surgery duration appears to be the only modifiable predictor of PPMV.

  15. Adoptive paternal age and risk of psychosis in adoptees: a register based cohort study.

    Directory of Open Access Journals (Sweden)

    Mats Ek

    Full Text Available The association between advancing paternal age and increased risk of schizophrenia in the off-spring is well established. The underlying mechanisms are unknown. In order to investigate whether the psychosocial environment associated with growing up with an aged father explains the increased risk we conducted a study of all adoptive children in Sweden from 1955-1985 (n =31 188. Their risk of developing schizophrenia or non-affective psychosis in relation to advancing age of their adoptive fathers' was examined. We found no association between risk of psychoses and advancing adoptive paternal age. There was no support of psychosocial environmental factors explaining the "paternal age effect".

  16. Mechanisms controlling the artificial aging of Al-Mg-Si Alloys

    International Nuclear Information System (INIS)

    Pogatscher, S.; Antrekowitsch, H.; Leitner, H.; Ebner, T.; Uggowitzer, P.J.

    2011-01-01

    Highlights: → Artificial aging of Al-Mg-Si alloys in the range of 150 and 250 deg. C. → We study precipitation kinetics caused by various thermal histories. → Natural pre-aging affects kinetics at low artificial aging temperatures. → Natural pre-aging promotes kinetics at high artificial aging temperatures. → A vacancy-prison mechanism explains the effect of natural pre-aging. - Abstract: In this study the artificial aging behavior of the Al-Mg-Si alloy AA 6061 was investigated in the temperature range 150-250 deg. C using atom probe tomography, hardness and resistivity measurements for various thermal histories. It was found that the precipitation kinetics and age-hardening response of artificial aging at temperatures below 210 deg. C are lowered by prior natural aging but enhanced above this temperature. An analysis of hardness data was used to evaluate the temperature dependence of precipitation kinetics and dissolution processes. Supported by theoretical considerations, it is assumed that artificial aging of Al-Mg-Si alloys is controlled via the concentration of mobile vacancies. The 'vacancy-prison mechanism' proposed determines the mobile vacancy concentration in the case of natural pre-aging by temperature-dependent dissolution of co-clusters and solute-vacancy interactions.

  17. NAD+ in Aging: Molecular Mechanisms and Translational Implications.

    Science.gov (United States)

    Fang, Evandro F; Lautrup, Sofie; Hou, Yujun; Demarest, Tyler G; Croteau, Deborah L; Mattson, Mark P; Bohr, Vilhelm A

    2017-10-01

    The coenzyme NAD + is critical in cellular bioenergetics and adaptive stress responses. Its depletion has emerged as a fundamental feature of aging that may predispose to a wide range of chronic diseases. Maintenance of NAD + levels is important for cells with high energy demands and for proficient neuronal function. NAD + depletion is detected in major neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases, cardiovascular disease and muscle atrophy. Emerging evidence suggests that NAD + decrements occur in various tissues during aging, and that physiological and pharmacological interventions bolstering cellular NAD + levels might retard aspects of aging and forestall some age-related diseases. Here, we discuss aspects of NAD + biosynthesis, together with putative mechanisms of NAD + action against aging, including recent preclinical and clinical trials. Published by Elsevier Ltd.

  18. Association between left ventricular mechanics and diffuse myocardial fibrosis in patients with repaired Tetralogy of Fallot: a cross-sectional study.

    Science.gov (United States)

    Haggerty, Christopher M; Suever, Jonathan D; Pulenthiran, Arichanah; Mejia-Spiegeler, Abba; Wehner, Gregory J; Jing, Linyuan; Charnigo, Richard J; Fornwalt, Brandon K; Fogel, Mark A

    2017-12-11

    Patients with repaired tetralogy of Fallot (TOF) have progressive, adverse biventricular remodeling, leading to abnormal contractile mechanics. Defining the mechanisms underlying this dysfunction, such as diffuse myocardial fibrosis, may provide insights into poor long-term outcomes. We hypothesized that left ventricular (LV) diffuse fibrosis is related to impaired LV mechanics. Patients with TOF were evaluated with cardiac magnetic resonance in which modified Look-Locker (MOLLI) T1-mapping and spiral cine Displacement encoding (DENSE) sequences were acquired at three LV short-axis positions. Linear mixed modeling was used to define the association between regional LV mechanics from DENSE based on regional T1-derived diffuse fibrosis measures, such as extracellular volume fraction (ECV). Forty patients (26 ± 11 years) were included. LV ECV was generally within normal range (0.24 ± 0.05). For LV mechanics, peak circumferential strains (-15 ± 3%) and dyssynchrony indices (16 ± 8 ms) were moderately impaired, while peak radial strains (29 ± 8%) were generally normal. After adjusting for patient age, sex, and regional LV differences, ECV was associated with log-adjusted LV dyssynchrony index (β = 0.67) and peak LV radial strain (β = -0.36), but not LV circumferential strain. Moreover, post-contrast T1 was associated with log-adjusted LV diastolic circumferential strain rate (β = 0.37). We observed several moderate associations between measures of fibrosis and impaired mechanics, particularly the LV dyssynchrony index and peak radial strain. Diffuse fibrosis may therefore be a causal factor in some ventricular dysfunction in TOF.

  19. Investigation of deterioration mechanism of electrical ceramic insulating materials under high temperature

    International Nuclear Information System (INIS)

    Mizutani, Yoshinobu; Ito, Tetsuo; Okamoto, Tatsuki; Kumazawa, Ryoji; Aizawa, Rie; Moriyama, Hideshige

    2000-01-01

    It is thought that ceramic insulator can be applied to electric power equipments that are under high temperature not to be able use organic materials. Our research has suggested components of mica-alumina combined insulation. As the results of and carried out temperature accelerating test, combined insulation life is expected long term over 40 years at over 500-Celsius degrees. However to construct high reliable insulating system, it is clarified deterioration mechanism on combined insulation and evaluates life of that. Therefore we carried out metal behavior test and voltage aging test using mica-sheet and alumina-cloth that are components of combined insulation under high temperature in nitrogen gas atmosphere. It is cleared two metal behavior mechanisms: One is that the opening of insulator are filled up with copper that is oxidized, the other is the metal diffuses in alumina-cloth through surface. And distance of metal behavior is able to be estimated at modulate temperature and in modulate time. It is also cleared that alumina-cloth is deteriorated by metal behavior into alumina-cloth. These results indicate that combined insulation is deteriorated from electrode side by metal behavior and is finally broken down through alumina-cloth. (author)

  20. THE ASSOCIATION BETWEEN AGEISM AND SUBJECTIVE AGE OF OLDER PEOPLE IN EUROPE

    Directory of Open Access Journals (Sweden)

    Moritz HESS

    2010-01-01

    Full Text Available Background: Stigmata on older people in society remains a big problem in the whole of Europe. It can lead to a lower self-esteem and is even as sociated with higher suicide rates. This study questioned whether the identification with one’s own age group is associated with an individual’s perceived stigma on the group of 70+, which has been unexamined so far for European citizens. Method: Data were derived from the European Social Survey (ESS. The sample consisted of 7878 persons aged 70+ stratified by three age groups. Group 1 = 70 – 75, Group 2= 76 – 80 and Group 3= >80. Independent T-test and Multiple regression analyses were used to examine influence of perceived stigmata in society on identification with one’s own age group, controlled for the covariates gender, household’s income, education, subjective general health, limitations in activities of daily life, marital status, having children living at home and having children not living at home. Results: A significant association was found for Group 1 (70 – 75 and Group 2 (76 – 80. Participants of these age groups, who reported a higher perception of stigmata for older people (70+, identified themselves less with their age group. No significant effect was found for Group 3 (people 80+. Conclusion: The results suggest that people older than 80 are less affected by stigmata of society on old age than younger groups (aged 70 - 80. Future research is necessary to examine the mechanisms which lead to a lower identification with their age of people aged 70 to 80.

  1. Age-associated sperm DNA methylation alterations: possible implications in offspring disease susceptibility.

    Directory of Open Access Journals (Sweden)

    Timothy G Jenkins

    2014-07-01

    Full Text Available Recent evidence demonstrates a role for paternal aging on offspring disease susceptibility. It is well established that various neuropsychiatric disorders (schizophrenia, autism, etc., trinucleotide expansion associated diseases (myotonic dystrophy, Huntington's, etc. and even some forms of cancer have increased incidence in the offspring of older fathers. Despite strong epidemiological evidence that these alterations are more common in offspring sired by older fathers, in most cases the mechanisms that drive these processes are unclear. However, it is commonly believed that epigenetics, and specifically DNA methylation alterations, likely play a role. In this study we have investigated the impact of aging on DNA methylation in mature human sperm. Using a methylation array approach we evaluated changes to sperm DNA methylation patterns in 17 fertile donors by comparing the sperm methylome of 2 samples collected from each individual 9-19 years apart. With this design we have identified 139 regions that are significantly and consistently hypomethylated with age and 8 regions that are significantly hypermethylated with age. A representative subset of these alterations have been confirmed in an independent cohort. A total of 117 genes are associated with these regions of methylation alterations (promoter or gene body. Intriguingly, a portion of the age-related changes in sperm DNA methylation are located at genes previously associated with schizophrenia and bipolar disorder. While our data does not establish a causative relationship, it does raise the possibility that the age-associated methylation of the candidate genes that we observe in sperm might contribute to the increased incidence of neuropsychiatric and other disorders in the offspring of older males. However, further study is required to determine whether, and to what extent, a causative relationship exists.

  2. Thermal aging effects of VVER-1000 weld metal under operation temperature

    International Nuclear Information System (INIS)

    Chernobaeva, A.A.; Kuleshova, E.A.; Gurovich, B.A.; Erak, D.Y.; Zabusov, O.O.; Maltsev, D.A.; Zhurko, D.A.; Papina, V.B.; Skundin, M.A.

    2015-01-01

    The VVER-1000 thermal aging surveillance specimen sets are located in the reactor pressure vessel (RPV) under real operation conditions. Thermal aging surveillance specimens data are the most reliable source of the information about changing of VVER-1000 RPV materials properties because of long-term (hundred thousand hours) exposure at operation temperature. A revision of database of VVER-1000 weld metal thermal aging surveillance specimens has been done. The reassessment of transition temperature (T t ) for all tested groups of specimens has been performed. The duration of thermal exposure and phosphorus contents have been defined more precisely. The analysis of thermal aging effects has been done. The yield strength data, study of carbides evolution show absence of hardening effects due to thermal aging under 310-320 C degrees. Measurements of phosphorus content in grain boundaries segregation in different states have been performed. The correlation between intergranular fracture mode in Charpy specimens and transition temperature shift under thermal aging at temperature 310-320 C degrees has been revealed. All these data allow developing the model of thermal aging. (authors)

  3. Empyema and bacteremic pneumococcal pneumonia in children under five years of age

    Directory of Open Access Journals (Sweden)

    Maria Regina Alves Cardoso

    2014-01-01

    Full Text Available We compared bacteremic pneumococcal pneumonia (BPP and pneumococcal empyema (PE, in terms of clinical, radiological, and laboratory findings, in under-fives. A cross-sectional nested cohort study, involving under-fives (102 with PE and 128 with BPP, was conducted at 12 centers in Argentina, Brazil, and the Dominican Republic. Among those with PE, mean age was higher; disease duration was longer; and tachypnea, dyspnea, and high leukocyte counts were more common. Among those with BPP, fever and lethargy were more common. It seems that children with PE can be distinguished from those with BPP on the basis of clinical and laboratory findings. Because both conditions are associated with high rates of morbidity and mortality, prompt diagnosis is crucial.

  4. Age and gender as independent predictors of violence under the influence of alcohol in Zurich, Switzerland.

    Science.gov (United States)

    Mica, Ladislav; Oesterle, Linda; Werner, Clément M L; Simmen, Hans-Peter

    2015-04-08

    Violent behaviour associated with alcohol consumption is frequently reported by different media. Clinical data analysing the correlation between alcohol intoxication, age, gender and violence are scarce. The aim of this study was to evaluate the influence of age, gender and blood alcohol content on violent behaviour under the influence of alcohol under central European conditions. Three hundred patients admitted to the emergency department were included into this study in the time period from January 01. to December 31. 2009. The inclusion criteria were a blood alcohol content (BAC) of ≥10 mmol/l, any traumatic injury and an age ≥16 years. Violence was defined as an evitable act committed by others leading to patient's hospitalisation. The data were compared with Wilcoxon and χ2-test for proportions. The data were considered as significant if pviolence with no correlation to blood alcohol content found. Logistic regression analysis revealed male gender and young age as an independent predictor for violence. These results clarify the relationship between alcohol, age, gender and violence and have important implications for municipal-level alcohol policies.

  5. Putting age-related task activation into large-scale brain networks: A meta-analysis of 114 fMRI studies on healthy aging.

    Science.gov (United States)

    Li, Hui-Jie; Hou, Xiao-Hui; Liu, Han-Hui; Yue, Chun-Lin; Lu, Guang-Ming; Zuo, Xi-Nian

    2015-10-01

    Normal aging is associated with cognitive decline and underlying brain dysfunction. Previous studies concentrated less on brain network changes at a systems level. Our goal was to examine these age-related changes of fMRI-derived activation with a common network parcellation of the human brain function, offering a systems-neuroscience perspective of healthy aging. We conducted a series of meta-analyses on a total of 114 studies that included 2035 older adults and 1845 young adults. Voxels showing significant age-related changes in activation were then overlaid onto seven commonly referenced neuronal networks. Older adults present moderate cognitive decline in behavioral performance during fMRI scanning, and hypo-activate the visual network and hyper-activate both the frontoparietal control and default mode networks. The degree of increased activation in frontoparietal network was associated with behavioral performance in older adults. Age-related changes in activation present different network patterns across cognitive domains. The systems neuroscience approach used here may be useful for elucidating the underlying network mechanisms of various brain plasticity processes during healthy aging. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  6. Corneal Mechanical Thresholds Negatively Associate With Dry Eye and Ocular Pain Symptoms.

    Science.gov (United States)

    Spierer, Oriel; Felix, Elizabeth R; McClellan, Allison L; Parel, Jean Marie; Gonzalez, Alex; Feuer, William J; Sarantopoulos, Constantine D; Levitt, Roy C; Ehrmann, Klaus; Galor, Anat

    2016-02-01

    To examine associations between corneal mechanical thresholds and metrics of dry eye. This was a cross-sectional study of individuals seen in the Miami Veterans Affairs eye clinic. The evaluation consisted of questionnaires regarding dry eye symptoms and ocular pain, corneal mechanical detection and pain thresholds, and a comprehensive ocular surface examination. The main outcome measures were correlations between corneal thresholds and signs and symptoms of dry eye and ocular pain. A total of 129 subjects participated in the study (mean age 64 ± 10 years). Mechanical detection and pain thresholds on the cornea correlated with age (Spearman's ρ = 0.26, 0.23, respectively; both P Dry eye symptom severity scores and Neuropathic Pain Symptom Inventory (modified for the eye) scores negatively correlated with corneal detection and pain thresholds (range, r = -0.13 to -0.27, P eye pain (pain to wind, light, temperature) and explained approximately 32% of measurement variability (R = 0.57). Mechanical detection and pain thresholds measured on the cornea are correlated with dry eye symptoms and ocular pain. This suggests hypersensitivity within the corneal somatosensory pathways in patients with greater dry eye and ocular pain complaints.

  7. Corneal Mechanical Thresholds Negatively Associate With Dry Eye and Ocular Pain Symptoms

    Science.gov (United States)

    Spierer, Oriel; Felix, Elizabeth R.; McClellan, Allison L.; Parel, Jean Marie; Gonzalez, Alex; Feuer, William J.; Sarantopoulos, Constantine D.; Levitt, Roy C.; Ehrmann, Klaus; Galor, Anat

    2016-01-01

    Purpose To examine associations between corneal mechanical thresholds and metrics of dry eye. Methods This was a cross-sectional study of individuals seen in the Miami Veterans Affairs eye clinic. The evaluation consisted of questionnaires regarding dry eye symptoms and ocular pain, corneal mechanical detection and pain thresholds, and a comprehensive ocular surface examination. The main outcome measures were correlations between corneal thresholds and signs and symptoms of dry eye and ocular pain. Results A total of 129 subjects participated in the study (mean age 64 ± 10 years). Mechanical detection and pain thresholds on the cornea correlated with age (Spearman's ρ = 0.26, 0.23, respectively; both P Dry eye symptom severity scores and Neuropathic Pain Symptom Inventory (modified for the eye) scores negatively correlated with corneal detection and pain thresholds (range, r = −0.13 to −0.27, P eye pain (pain to wind, light, temperature) and explained approximately 32% of measurement variability (R = 0.57). Conclusions Mechanical detection and pain thresholds measured on the cornea are correlated with dry eye symptoms and ocular pain. This suggests hypersensitivity within the corneal somatosensory pathways in patients with greater dry eye and ocular pain complaints. PMID:26886896

  8. Parental and Child Factors Associated with Under-Estimation of Children with Excess Weight in Spain.

    Science.gov (United States)

    de Ruiter, Ingrid; Olmedo-Requena, Rocío; Jiménez-Moleón, José Juan

    2017-11-01

    Objective Understanding obesity misperception and associated factors can improve strategies to increase obesity identification and intervention. We investigate underestimation of child excess weight with a broader perspective, incorporating perceptions, views, and psychosocial aspects associated with obesity. Methods This study used cross-sectional data from the Spanish National Health Survey in 2011-2012 for children aged 2-14 years who are overweight or obese. Percentages of parental misperceived excess weight were calculated. Crude and adjusted analyses were performed for both child and parental factors analyzing associations with underestimation. Results Two-five year olds have the highest prevalence of misperceived overweight or obesity around 90%. In the 10-14 year old age group approximately 63% of overweight teens were misperceived as normal weight and 35.7 and 40% of obese males and females. Child gender did not affect underestimation, whereas a younger age did. Aspects of child social and mental health were associated with under-estimation, as was short sleep duration. Exercise, weekend TV and videogames, and food habits had no effect on underestimation. Fathers were more likely to misperceive their child´s weight status; however parent's age had no effect. Smokers and parents with excess weight were less likely to misperceive their child´s weight status. Parents being on a diet also decreased odds of underestimation. Conclusions for practice This study identifies some characteristics of both parents and children which are associated with under-estimation of child excess weight. These characteristics can be used for consideration in primary care, prevention strategies and for further research.

  9. [Screening of anti-aging active ingredients and mechanism analysis based on molecular docking technology].

    Science.gov (United States)

    Du, Ran-Feng; Zhang, Xiao-Hua; Ye, Xiao-Tong; Yu, Wen-Kang; Wang, Yun

    2016-07-01

    Dampness evil is the source of all diseases, which is easy to cause disease and promote aging, while aging could also promote the occurence and development of diseases. In this paper, the relationship between the dampness evil and aging would be discussed, to find the anti-aging active ingredients in traditional Chinese medicine (TCM), and analyze the anti-aging mechanism of dampness eliminating drug. Molecular docking technology was used, with aging-related mammalian target of rapamycin as the docking receptors, and chemical components of Fuling, Sangzhi, Mugua, Yiyiren and Houpo as the docking molecules, to preliminarily screen the anti-aging active ingredients in dampness eliminating drug. Through the comparison with active drugs already on the market (temsirolimus and everolimus), 12 kinds of potential anti-aging active ingredients were found, but their drug gability still needs further study. The docking results showed that various components in the dampness eliminating drug can play anti-aging activities by acting on mammalian target of rapamycin. This result provides a new thought and direction for the method of delaying aging by eliminating dampness. Copyright© by the Chinese Pharmaceutical Association.

  10. [Research of anti-aging mechanism of ginsenoside Rg1 on brain].

    Science.gov (United States)

    Li, Cheng-peng; Zhang, Meng-si; Liu, Jun; Geng, Shan; Li, Jing; Zhu, Jia-hong; Zhang, Yan-yan; Jia, Yan-yan; Wang, Lu; Wang, Shun-he; Wang, Ya-ping

    2014-11-01

    . Rats of Rg1 brain aging group had their spatial learning and memory capacities enhanced, SA-beta-Gal positive granules in section of brain tissue decreased, the activity of antioxidant enzyme SOD and the contents of GSH increased in hippocampus, the level of IL-1 and IL-6 in hippocampus decreased, the length contraction of telomere suppressed while the change of telomerase activity increased in hippocampus. Compared with that of normal group, the spatial learning and memory capacities were enhanced in Rg1 normal group, SA-beta-Gal positive granules in section of brain tissue decreased in Rg1 normal group, the level of IL-1 and IL-6 in hippocampus decreased in Rg1 normal group. The results indicated that improvement of antioxidant ability, regulating the level of proinflammatory cytokines and regulation of telomerase system may be the underlying anti-aging mechanism of Ginsenoside Rg1.

  11. Effect of conventional and subzero treating on the mechanical properties of aged martensitic Fe-12 wt.% Ni-X wt.% Mn alloys

    International Nuclear Information System (INIS)

    Nedjad, S. Hossein; Nili-Ahmadabadi, M.; Mahmudi, R.; Farhangi, H.

    2003-01-01

    Fe-Ni-Mn maraging alloys are suffering from sever embrittlement after aging. Mechanism of the embrittelement has not been well understood yet. Segregation of Mn atoms or formation of Austenite particles at prior Austenite grain boundaries (PAGBs) have been reported as embrittelement mechanisms while it remains controversial now. For better understanding of embrittelement behavior, effect of subzero treating after aging, double aging and modification of alloy composition on the mechanical properties and fracture behavior were investigated. Alloys of chemical compositions Fe-11.9 wt.% Ni-6.3 wt.% Mn and Fe-10.5 wt.% Ni-5.8 wt.% Mo-3 wt.% Mn were studied. Double solution annealing was performed at 1223 and 1093 K for 3.6 ks followed by water quenching. After aging at 723 K for 0.9 ks (under aging) and 172.8 ks (over aging), tensile properties of specimens heat treated conventionally and cryogenically were measured. Double aging was done at 623 K for 3.6 ks followed by a step aging at 753, 783 and 803 K. Aging behavior and tensile properties of Fe-10.5 wt.% Ni-5.8 wt.% Mo-3 wt.% Mn were investigated after aging at 773 K. Results showed that alloy modification yields reasonable tensile properties while subzero treatment and double aging couldn't improve tensile properties. An insight toward more investigation of the embrittelement mechanism was made on the basis of this study

  12. Similar verbal memory impairments in schizophrenia and healthy aging. Implications for understanding of neural mechanisms.

    Science.gov (United States)

    Silver, Henry; Bilker, Warren B

    2015-03-30

    Memory is impaired in schizophrenia patients but it is not clear whether this is specific to the illness and whether different types of memory (verbal and nonverbal) or memories in different cognitive domains (executive, object recognition) are similarly affected. To study relationships between memory impairments and schizophrenia we compared memory functions in 77 schizophrenia patients, 58 elderly healthy individuals and 41 young healthy individuals. Tests included verbal associative and logical memory and memory in executive and object recognition domains. We compared relationships of memory functions to each other and to other cognitive functions including psychomotor speed and verbal and spatial working memory. Compared to the young healthy group, schizophrenia patients and elderly healthy individuals showed similar severe impairment in logical memory and in the ability to learn new associations (NAL), and similar but less severe impairment in spatial working memory and executive and object memory. Verbal working memory was significantly more impaired in schizophrenia patients than in the healthy elderly. Verbal episodic memory impairment in schizophrenia may share common mechanisms with similar impairment in healthy aging. Impairment in verbal working memory in contrast may reflect mechanisms specific to schizophrenia. Study of verbal explicit memory impairment tapped by the NAL index may advance understanding of abnormal hippocampus dependent mechanisms common to schizophrenia and aging. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  13. Elemental, microstructural, and mechanical characterization of high gold orthodontic brackets after intraoral aging.

    Science.gov (United States)

    Hersche, Sepp; Sifakakis, Iosif; Zinelis, Spiros; Eliades, Theodore

    2017-02-01

    The purpose of the present study was to investigate the elemental composition, the microstructure, and the selected mechanical properties of high gold orthodontic brackets after intraoral aging. Thirty Incognito™ (3M Unitek, Bad Essen, Germany) lingual brackets were studied, 15 brackets as received (control group) and 15 brackets retrieved from different patients after orthodontic treatment. The surface of the wing area was examined by scanning electron microscopy (SEM). Backscattered electron imaging (BEI) was performed, and the elemental composition was determined by X-ray EDS analysis (EDX). After appropriate metallographic preparation, the mechanical properties tested were Martens hardness (HM), indentation modulus (EIT), elastic index (ηIT), and Vickers hardness (HV). These properties were determined employing instrumented indentation testing (IIT) with a Vickers indenter. The results were statistically analyzed by unpaired t-test (α=0.05). There were no statistically significant differences evidenced in surface morphology and elemental content between the control and the experimental group. These two groups of brackets showed no statistically significant difference in surface morphology. Moreover, the mean values of HM, EIT, ηIT, and HV did not reach statistical significance between the groups (p>0.05). Under the limitations of this study, it may be concluded that the surface elemental content and microstructure as well as the evaluated mechanical properties of the Incognito™ lingual brackets remain unaffected by intraoral aging.

  14. Chelation: A Fundamental Mechanism of Action of AGE Inhibitors, AGE Breakers, and Other Inhibitors of Diabetes Complications

    Energy Technology Data Exchange (ETDEWEB)

    Nagai, Rhoji; Murray, David B.; Metz, Thomas O.; Baynes, John

    2012-03-01

    Advanced glycation or glycoxidation end-products (AGE) increase in tissue proteins with age, and their rate of accumulation is increased in diabetes, nephropathy and inflammatory diseases. AGE inhibitors include a range of compounds that are proposed to act by trapping carbonyl and dicarbonyl intermediates in AGE formation. However, some among the newer generation of AGE inhibitors lack reactive functional groups that would trap reaction intermediates, indicating an alternative mechanism of action. We propose that AGE inhibitors function primarily as chelators, inhibiting metal-catalyzed oxidation reactions. The AGE-inhibitory activity of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers is also consistent with their chelating activity. Finally, compounds described as AGE breakers, or their hydrolysis products, also have strong chelating activity, suggesting that these compounds also act through their chelating activity. We conclude that chelation is the common, and perhaps the primary, mechanism of action of AGE inhibitors and breakers, and that chronic, mild chelation therapy should prove useful in treatment of diabetes and age-related diseases characterized by oxidative stress, inflammation and increased chemical modification of tissue proteins by advanced glycoxidation and lipoxidation end-products.

  15. Relation of murine thoracic aortic structural and cellular changes with aging to passive and active mechanical properties.

    Science.gov (United States)

    Wheeler, Jason B; Mukherjee, Rupak; Stroud, Robert E; Jones, Jeffrey A; Ikonomidis, John S

    2015-02-25

    Maintenance of the structure and mechanical properties of the thoracic aorta contributes to aortic function and is dependent on the composition of the extracellular matrix and the cellular content within the aortic wall. Age-related alterations in the aorta include changes in cellular content and composition of the extracellular matrix; however, the precise roles of these age-related changes in altering aortic mechanical function are not well understood. Thoracic aortic rings from the descending segment were harvested from C57BL/6 mice aged 6 and 21 months. Thoracic aortic diameter and wall thickness were higher in the old mice. Cellular density was reduced in the medial layer of aortas from the old mice; concomitantly, collagen content was higher in old mice, but elastin content was similar between young and old mice. Stress relaxation, an index of compliance, was reduced in aortas from old mice and correlated with collagen fraction. Contractility of the aortic rings following potassium stimulation was reduced in old versus young mice. Furthermore, collagen gel contraction by aortic smooth muscle cells was reduced with age. These results demonstrate that numerous age-related structural changes occurred in the thoracic aorta and were related to alterations in mechanical properties. Aortic contractility decreased with age, likely because of a reduction in medial cell number in addition to a smooth muscle contractile deficit. Together, these unique findings provide evidence that the age-related changes in structure and mechanical function coalesce to provide an aortic substrate that may be predisposed to aortopathies. © 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

  16. Age-Associated Decline in Thymic B Cell Expression of Aire and Aire-Dependent Self-Antigens

    Directory of Open Access Journals (Sweden)

    Sergio Cepeda

    2018-01-01

    Full Text Available Although autoimmune disorders are a significant source of morbidity and mortality in older individuals, the mechanisms governing age-associated increases in susceptibility remain incompletely understood. Central T cell tolerance is mediated through presentation of self-antigens by cells constituting the thymic microenvironment, including epithelial cells, dendritic cells, and B cells. Medullary thymic epithelial cells (mTECs and B cells express distinct cohorts of self-antigens, including tissue-restricted self-antigens (TRAs, such that developing T cells are tolerized to antigens from peripheral tissues. We find that expression of the TRA transcriptional regulator Aire, as well as Aire-dependent genes, declines with age in thymic B cells in mice and humans and that cell-intrinsic and cell-extrinsic mechanisms contribute to the diminished capacity of peripheral B cells to express Aire within the thymus. Our findings indicate that aging may diminish the ability of thymic B cells to tolerize T cells, revealing a potential mechanistic link between aging and autoimmunity.

  17. Age related association of her-2/neu with prognostic markers in female breast carcinoma

    International Nuclear Information System (INIS)

    Sharif, M.A.; Mamoon, N.; Mushtaq, S.; Khadim, M.T.

    2010-01-01

    To determine age-related association of Her-2/neu expression with histological and immunohistochemical prognostic markers in female breast carcinoma. Study Design: Cross sectional, observational study. Place and Duration of Study: Department of Histopathology, Armed Forces Institute of Pathology, Rawalpindi, from January 2004 to December 2007. Methodology: Patients of primary operable female breast carcinoma were categorised as 50 years (post-menopausal) age groups. Histological type, tumour size, tumour grade and lymph node status were determined while estrogen receptor (ER), progesterone receptor (PR) and Her-2/neu expression were evaluated immunohistochemically. Association of Her-2/neu with histological and immunohistochemical prognostic markers was determined in pre-menopausal, peri-menopausal and post- menopausal age groups using the x2 test for uni- and multivariate analysis. Results: Out of the 722 patients, 230 (31.9%) were in pre-menopuasal, 221 (30.6%) in peri-menopausal and 271 (37.5%) in post-menopausal age group. Infiltrating ductal carcinoma was the pre-dominant subtype in all the age groups. Mean tumour size was 4.3 +- 2.3 cm (range 0.4-17 cm) and lymph node metastasis was seen in 310 (70.8%) cases. Her-2/neu showed association with ER in the all the age groups while PR only showed association in the peri-menopausal and postmenopausal women. Her-2/neu showed no association with tumour size, tumor grade and lymph node metastases in pre-menopausal and peri-menopausal women while it showed positive association with tumour size and lymph node metastasis in the post-menopausal women (p < 0.05). Conclusion: Majority (62%) patients were under 50 years as against the Western epidemiology. Association of Her-2/neu with ER, PR, tumour size and lymph node metastasis was age related as pre-menopausal, peri-menopausal and postmenopausal had variable expression of these prognostic markers with therapeutic and prognostic implications. (author)

  18. Review of mechanical properties and microstructures of types 304 and 316 stainless steel after long-term aging

    International Nuclear Information System (INIS)

    Horak, J.A.; Sikka, V.K.; Raske, D.T.

    Because commercial liquid metal fast breeder reactors (LMFBRs) will be designed to last for 35 to 40 years, an understanding of the mechanical behavior of the structural alloys used is required for times of 2.2 to 2.5x10 5 h (assuming a 70% availability factor). Types 304 and 316 stainless steel are used extensively in LMFBR systems. These alloys are in a metastable state when installed and evolve to a more stable state and, therefore, microstructure during plant operation. Correlations of microstructures and mechanical properties during aging under representative LMFBR temperature and loading conditions is desirable from the standpoint of assuring safe, reliable, and economic plant operation. We reviewed the mechanical properties and microstructures of types 304 and 316 stainless steel wrought alloys, welds, and castings after long-term aging in air to 9x10 4 h (about 10-1/2 years). The principal effect of such aging is to reduce fracture toughness (as measured in Charpy impact tests) and tensile ductility. Examples are cited, however, where, because stable microstructures are achieved, these as well as strength-related properties can be expected to remain adequate for service life exposures. (author)

  19. Influence of fillers on mechanical properties of filled rubbers during ageing by irradiation

    International Nuclear Information System (INIS)

    Planes, Emilie

    2008-01-01

    The understanding of the evolution of mechanical properties and the prediction of the lifetime of material environment is a recurring problem. This question is very important to develop polymer formulations used for electrical cables in nuclear power plants. Thus it is important to know the evolution of materials when they are submitted to usual conditions in nuclear power plants. There are in literature some studies concerning the ageing by gamma irradiation of unfilled elastomer but the addition of fillers in the material can have consequences on the evolution of the mechanical properties during irradiation. Thus this work concerns the study of the ageing by gamma irradiation of filled rubbers and the identification of the role of fillers in the degradation mechanisms. The studied matrix, which commonly used for the type of application is EPDM. The fillers are: nano-scopic silica and aluminium trihydrate. Their surfaces have been treated in order to understand the role of filler-matrix interfaces during ageing. To evaluate the influence of fillers on the degradation mechanisms and on the evolution of the mechanical properties, the evolution during ageing of these materials filled or not has been studied for an ageing by irradiation: they have been physico-chemically, micro-structurally and mechanically characterized at various levels of ageing [fr

  20. [Child malnutrition in children under 5 years of age in Peru: trends and determinants].

    Science.gov (United States)

    Sobrino, Manuel; Gutiérrez, César; Cunha, Antonio J; Dávila, Miguel; Alarcón, Jorge

    2014-02-01

    Analyze malnutrition and anemia trends in Peruvian children under 5 years of age and their association with determinants in the 2000-2011 period. Nutritional indicators for children under 5 years of age from the 2011 Demographic and Family Health Survey (ENDES), and their evolution based on data from the 2000, 2005, and 2008 ENDES, were analyzed. Chronic malnutrition (CM) (height/age ≤ 2 SD), acute malnutrition (AM), (height/weight ≤ 2 SD), and anemia trends were estimated. Associations were found with factors such as sex, age, area of residence (urban or rural), region of residence, mother's education, wealth quintile, availability of public water system, sewer availability, altitude, presence of other children in household, birth order, presence of diarrhea in previous 15 days, and presence of cough in previous 15 days. AM, CM, and anemia in Peruvian children under 5 years of age decreased from 2000-2011. This reduction was not uniform for the three conditions, with decreases of 1.1% to 0.4% recorded for AM, 31.6% to 19.6% for CM, and 50.4% to 30.7% for anemia. Although the factors analyzed were related to the prevalence of these three illnesses, calculation of the adjusted odds ratios showed significant differences for CM (mother's education, Sierra region, altitude greater than 2 500 m above sea level, presence of two or more children in household, and being the third or successive child) and anemia (child sex [higher in males], children under 2 years of age, Resto de costa region and Selva region, altitude greater than 2 500 m above sea level, availability of public water system, sewer availability, presence of two or more children in household, and presence of diarrhea within 15 days prior to the survey). For AM, differences were observed according to some factors but they were not significant in the adjusted model. In the 2000-2011 period, Peru achieved reduction of its CM, AM, and anemia rates. AM rates decreased to almost one-third, with overall

  1. The relationship between age-stereotypes and health locus of control across adult age-groups.

    Science.gov (United States)

    Sargent-Cox, Kerry; Anstey, Kaarin J

    2015-01-01

    This study integrates healthy ageing and health psychology theories to explore the mechanisms underlying the relationship between health control expectancies and age-attitudes on the process of ageing well. Specifically, the aim of this study is to investigate the relationship between age-stereotypes and health locus of control. A population-based survey of 739 adults aged 20-97 years (mean = 57.3 years, SD = 13.66; 42% female) explored attitudes towards ageing and health attitudes. A path-analytical approach was used to investigate moderating effects of age and gender. Higher age-stereotype endorsement was associated with higher chance (β = 2.91, p education and self-rated health. Significant age and gender interactions were found to influence the relationship between age-stereotypes and internal health locus of control. Our findings suggest that the relationship between age-stereotypes and health locus of control dimensions must be considered within the context of age and gender. The findings point to the importance of targeting health promotion and interventions through addressing negative age-attitudes.

  2. Thermal ageing of steels; from expertise and understanding of the ageing mechanisms to a maintenance strategy for operating nuclear power plants

    International Nuclear Information System (INIS)

    Bezdikian, G.; Ould, P.

    2004-01-01

    Some parts of reactor coolant circuit on Nuclear PWR power plants, elbows on primary circuit, are made in cast duplex stainless steel material. It is now identify that the mechanical characteristic of this material should be decrease under thermal ageing mainly after a long time in operation in at reactor coolant circuit temperature conditions. The sensitiveness to the thermal ageing of these components is in relation with chemical composition and the ferrite content, especially the grade of Chromium equivalent (Ceq %Cr + %Si + %Mo). In the context of justification to maintain in operation on the plants these cat duplex components, an important programme of expertises was carried out on cast elbows after removing on the plants during the Steam Generators replacements (SGR). Several expertises, performed in the objective to understand the thermal ageing phenomenon and mechanism on cast components in service on plants, were permit to validate the prediction formulas established from a large database and programme in laboratories. The expertises were based on a lot of metallurgical, mechanical and chemical characteristics of components in operation Small Angle Neutrons Scattering (SANS), Thermal Electric Power (TEP), micro hardness and toughness measurement on small specimens from boat sample (CT10-5) The expertise carried out on one SG inlet elbows from DAMPIERRE, removed a during SGR after 100000 h in operation is shown, the toughness values are very high compared to the prediction formulas. The TEP measurements performed on the specimen cut off on two elbows and the ingots of the same material aged in laboratory in furnace, are very coherent; it is confirmed that this methodology is a good indicator to follow the ageing characteristic of material. The results of expertises on aged material are a mean of validation of the methodology applied on the file of demonstration of maintaining in operation of cast duplex stainless steel sensitive to thermal ageing. So the

  3. Associations between cognitively stimulating leisure activities, cognitive function and age-related cognitive decline.

    Science.gov (United States)

    Ferreira, Nicola; Owen, Adrian; Mohan, Anita; Corbett, Anne; Ballard, Clive

    2015-04-01

    Emerging literature suggests that lifestyle factors may play an important role in reducing age-related cognitive decline. There have, however, been few studies investigating the role of cognitively stimulating leisure activities in maintaining cognitive health. This study sought to identify changes in cognitive performance with age and to investigate associations of cognitive performance with several key cognitively stimulating leisure activities. Over 65,000 participants provided demographic and lifestyle information and completed tests of grammatical reasoning, spatial working memory, verbal working memory and episodic memory. Regression analyses suggested that frequency of engaging in Sudoku or similar puzzles was significantly positively associated with grammatical reasoning, spatial working memory and episodic memory scores. Furthermore, for participants aged under 65 years, frequency of playing non-cognitive training computer games was also positively associated with performance in the same cognitive domains. The results also suggest that grammatical reasoning and episodic memory are particularly vulnerable to age-related decline. Further investigation to determine the potential benefits of participating in Sudoku puzzles and non-cognitive computer games is indicated, particularly as they are associated with grammatical reasoning and episodic memory, cognitive domains found to be strongly associated with age-related cognitive decline. Results of this study have implications for developing improved guidance for the public regarding the potential value of cognitively stimulating leisure activities. The results also suggest that grammatical reasoning and episodic memory should be targeted in developing appropriate outcome measures to assess efficacy of future interventions, and in developing cognitive training programmes to prevent or delay cognitive decline. Copyright © 2014 John Wiley & Sons, Ltd.

  4. Testosterone deficiency causes penile fibrosis and organic erectile dysfunction in aging men. Evaluating association among Age, TDS and ED.

    Science.gov (United States)

    Iacono, Fabrizio; Prezioso, Domenico; Ruffo, Antonio; Illiano, Ester; Romis, Leo; Di Lauro, G; Romeo, Giuseppe; Amato, Bruno

    2012-01-01

    We studied the possible correlation between age, testosterone deficiency, cavernosal fibrosis and erectile dysfunction (ED). 47 patients with ED were enrolled between September 2010 and October 2011. IIEF-EF score, NPTR test using the Rigiscan method, total and free testosterone levels, and cavernosum biopsy were carried out on all patients. Patients aged 65 or over were defined as Old Age (OA) while patients under 65 were defined Young age (YA). The strength of the relationships found was estimated by Odds Ratio. 74% of patients with values of over 52% collagen fibers in the corpora cavernosa were found to have organic ED. A significant difference was found in age, percentage of collagen fibers, testosterone levels between patients with Positive Rigiscan (PR) and Negative Rigiscan (NR). Hypotestosteronaemia increased the risk of ED with PR (OR: 21.4, 95% CI: 20.2-22.6) and in both young age patients (OR: 4.3, 95% CI: 2.4-6.2) and old age patients (OR: 15.5, 95% CI: 13.4-17.6). Moreover cavernosal fibrosis increased the risk of ED with PR in both young age patients (OR: 8.2, 95% CI: 6.4-10.0 and old age patients (OR: 24.6, 95% CI: 20.8-28.4). This study demonstrates a strong association among age, testosterone deficiency, cavernosal fibrosis and ED with PR. Age, testosterone deficiency and cavernosal fibrosis are potentially correctable factors of cavernosal fibrosis and organic ED. Further, prospective studies are needed to evaluate if testosterone treatment, alone or in association with PDE5 inhibitors, may lower the risk of cavernosal fibrosis or decrease the severity the fibrosis in ED patients.

  5. Molecular mechanisms of aging and immune system regulation in Drosophila.

    Science.gov (United States)

    Eleftherianos, Ioannis; Castillo, Julio Cesar

    2012-01-01

    Aging is a complex process that involves the accumulation of deleterious changes resulting in overall decline in several vital functions, leading to the progressive deterioration in physiological condition of the organism and eventually causing disease and death. The immune system is the most important host-defense mechanism in humans and is also highly conserved in insects. Extensive research in vertebrates has concluded that aging of the immune function results in increased susceptibility to infectious disease and chronic inflammation. Over the years, interest has grown in studying the molecular interaction between aging and the immune response to pathogenic infections. The fruit fly Drosophila melanogaster is an excellent model system for dissecting the genetic and genomic basis of important biological processes, such as aging and the innate immune system, and deciphering parallel mechanisms in vertebrate animals. Here, we review the recent advances in the identification of key players modulating the relationship between molecular aging networks and immune signal transduction pathways in the fly. Understanding the details of the molecular events involved in aging and immune system regulation will potentially lead to the development of strategies for decreasing the impact of age-related diseases, thus improving human health and life span.

  6. Mechanical properties of cellulose electro-active paper under different environmental conditions

    International Nuclear Information System (INIS)

    Kim, Heung Soo; Kim, Jaehwan; Jung, Woochul; Ampofo, Joshua; Craft, William; Sankar, Jagannathan

    2008-01-01

    The mechanical properties of cellulose-based electro-active paper (EAPap) are investigated under various environmental conditions. Cellulose EAPap has been discovered as a smart material that can be used as both sensor and actuator. Its advantages include low voltage operation, light weight, low power consumption, biodegradability and low cost. EAPap is made with cellulose paper coated with thin electrodes. EAPap shows a reversible and reproducible bending movement as well as longitudinal displacement under an electric field. However, EAPap is a complex anisotropic material which has not been fully characterized. This study investigates the mechanical properties of cellulose-based EAPap, including Young's modulus, yield strength, ultimate strength and creep, along with orientation directions, humidity and temperature levels. To test the materials in different humidity and temperature levels, a special material testing system was made that can control the testing environmental conditions. The initial Young's modulus of EAPap is in the range of 4–9 GPa, which was higher than that of other polymer materials. Also, the Young's modulus is orientation dependent, which may be associated with the piezoelectricity of EAPap materials. The elastic strength and stiffness gradually decreased when the humidity and temperature were increased. Creep and relaxation were observed under constant stress and strain, respectively. Through scanning electron microscopy, EAPap is shown to exhibit both layered and oriented cellulose macromolecular structures that impact both the elastic and plastic behavior

  7. PREVALENCE AND ASSOCIATED FACTORS OF FLATFOOT AMONG 6 TO 10 AGED CHILDREN IN CENTRAL PROVINCE OF SRI LANKA

    Directory of Open Access Journals (Sweden)

    V.V. Senadheera

    2016-06-01

    Full Text Available Background: Prevalence of flatfoot is highly variable in different world populations. Previous studies have found that many factors are associated with flatfoot. The objective of the present study was to investigate the prevalence of flatfoot and its association with age, gender and BMI in group of 6-10 aged children in Central province of Sri Lanka. Methods: A total of 722 children aged 6 to 10 were used to assess normalize navicular height using two clinical measurements (navicular height, truncated foot length. Weight and height of the subjects were measured to calculate body mass index. Age and gender of the children were also recorded. Calculated normalize navicular heights were plotted in a distribution curve and area under the curve between +1SD and -1SD was considered as normal foot. Area under the curve which is left to the -1SD was considered as flatfoot. Results: Overall prevalence of flatfoot among 6-10 aged children in the present sample was 16.06%. The prevalence of flatfoot in 6,7,8,9 and 10 aged children were 26.35%, 16.19%, 12.75%, 13.57% and 11.1%, respectively. Prevalence of flatfoot was high in overweight children (21.05%. Prevalence of flatfoot among males and females were 47% and 53%,respectively. Conclusion: This study suggests that there is a significant association between flatfoot and age (p<0.05. Prevalence of flat foot decreases with advancing age. Furthermore, there is a significant association between flatfoot and body mass index (p<0.05. Prevalence of flatfoot is higher in overweight children than normal weight and underweight children. There is no significant association between flatfoot and gender.

  8. Molecular and histological characterization of age spots

    Science.gov (United States)

    Choi, Wonseon; Yin, Lanlan; Smuda, Christoph; Batzer, Jan; Hearing, Vincent J.; Kolbe, Ludger

    2016-01-01

    Age spots, also called solar lentigines and lentigo senilis, are light brown to black pigmented lesions of various sizes that typically develop in chronically sun-exposed skin. It is well known that age spots are strongly related to chronic sun exposure and are associated with photodamage and an increased risk for skin cancer, however, the mechanism(s) underlying their development remain poorly understood. We used immunohistochemical analysis and microarray analysis to investigate the processes involved in their formation, focusing on specific markers associated with the functions and proliferation of melanocytes and keratinocytes. A total of 193 genes were differentially expressed in age spots but melanocyte pigment genes were not among them. The increased expression of keratins 5 and 10, markers of basal and suprabasal keratinocytes, respectively, in age spots suggests that the increased proliferation of basal keratinocytes combined with the decreased turnover of suprabasal keratinocytes leads to the exaggerated formation of rete ridges in lesional epidermis which in turn disrupts the normal processing of melanin upwards from the basal layer. Based on our results, we propose a model for the development of age spots that explains the accumulation of melanin and the development of extensive rete ridges in those hyperpigmented lesions. PMID:27621222

  9. Livestock ownership is associated with higher odds of anaemia among preschool-aged children, but not women of reproductive age in Ghana.

    Science.gov (United States)

    Jones, Andrew D; Colecraft, Esi K; Awuah, Raphael B; Boatemaa, Sandra; Lambrecht, Nathalie J; Adjorlolo, Leonard Kofi; Wilson, Mark L

    2018-04-02

    Livestock ownership may influence anaemia through complex and possibly contradictory mechanisms. In this study, we aimed to determine the association of household livestock ownership with anaemia among women aged 15-49 years and children aged 6-59 months in Ghana and to examine the contribution of animal source foods (ASFs) to consumption patterns as a potential mechanism mediating this association. We analysed data on 4,441 women and 2,735 children from the 2014 Ghana Demographic and Health Survey and 16,772 households from the Ghana Living Standards Survey Round 6. Haemoglobin measurements were used to define anaemia (non-pregnant women: <120 g/L; children: <110 g/L). Child- and household-level ASF consumption data were collected from 24-hour food group intake and food consumption and expenditure surveys, respectively. In multiple logistic regression models, household livestock ownership was associated with anaemia among children (OR, 95% CI: 1.5 [1.1, 2.0]), but not women (1.0 [0.83, 1.2]). Household ownership of chickens was associated with higher odds of anaemia among children (1.6 [1.2, 2.2]), but ownership of other animal species was not associated with anaemia among women or children. In path analyses, we observed no evidence of mediation of the association of household livestock ownership with child anaemia by ASF consumption. Ownership of livestock likely has limited importance for consumption of ASFs among young children in Ghana and may in fact place children at an increased risk of anaemia. Further research is needed to elucidate if and how pathogen exposure associated with livestock rearing may underlie this increased risk of anaemia. © 2018 The Authors. Maternal and Child Nutrition Published by John Wiley & Sons, Ltd.

  10. Ageing of palladium tritide: mechanical characterization, helium state and modelling

    International Nuclear Information System (INIS)

    Segard, M.

    2010-01-01

    Palladium is commonly used for the storage of tritium (the hydrogen radioactive isotope), since it forms a low-equilibrium-pressure and reversible tritide. Tritium decay into helium-3 is responsible for the ageing of the tritide, leading to the apparition of helium-3 bubbles for instance. Both experimental and theoretical aspects of this phenomenon are studied here.Previous works on ageing modelling led to two main models, dealing with:- Helium-3 bubbles nucleation (using a cellular automaton), - Bubbles growth (using continuum mechanics).These models were quite efficient, but their use was limited by the lack of input data and fitting experimental parameters.To get through these limitations, this work has consisted in studying the most relevant experimental data to improve the modelling of the palladium tritide ageing.The first part of this work was focused on the assessment of the mechanical properties of the palladium tritide (yield strength, ultimate strength, mechanical behaviour). They were deduced from the in situ tensile tests performed on palladium hydride and deuteride. In the second part, ageing characterization was undertaken, mainly focusing on: - Bubbles observations in palladium tritide using transmission electron microscopy, - Internal bubble pressure measurements using nuclear magnetic resonance, - Macroscopic swelling measurements using pycno-metry.The present work has led to significant progress in ageing understanding and has brought very valuable improvements to the modelling of such a phenomenon. (author) [fr

  11. Phase decomposition and morphology characteristic in thermal aging Fe–Cr alloys under applied strain: A phase-field simulation

    International Nuclear Information System (INIS)

    Li Yongsheng; Zhu Hao; Zhang Lei; Cheng Xiaoling

    2012-01-01

    Highlights: ► Effects of variation mobility and applied strain on phase decomposition of Fe–Cr alloy were studied. ► Rate of phase decomposition rises as aging temperature and concentration increase. ► Phase transformation mechanism affects the volume fraction of equilibrium phase. ► Elongate morphology is intensified at higher aging temperature under applied strain. - Abstract: The phase decomposition and morphology evolution in thermal aging Fe–Cr alloys were investigated using the phase field method. In the simulation, the effects of atomic mobility, applied strain, alloy concentration and aging temperature were studied. The simulation results show that the rate of phase decomposition is influenced by the aging temperature and the alloy concentration, the equilibrium volume fractions (V f e ) of Cr-rich phase increases as aging temperature rises for the alloys of lower concentration, and the V f e decreases for the alloys with higher concentration. Under the applied strain, the orientation of Cr-rich phase is intensified as the aging temperature rises, and the stripe morphology is formed for the middle concentration alloys. The simulation results are helpful for understanding the phase decomposition in Fe–Cr alloys and the designing of duplex stainless steels working at high temperature.

  12. Metabolic syndrome and dementia associated with Parkinson's disease: impact of age and hypertension

    Directory of Open Access Journals (Sweden)

    Arthur Oscar Schelp

    2012-02-01

    Full Text Available OBJECTIVE: To determine correlations between age and metabolic disorders in Parkinson's disease (PD patients. METHODS: This observational cross-sectional study included brief tests for dementia and the Mattis test. Signals of metabolic syndrome were evaluated. RESULTS: There was no significant effect from the presence of hypertension (OR=2.36 for patients under 65 years old and OR=0.64 for patients over 65, diabetes or hypercholesterolemia regarding occurrences of dementia associated with PD (24% of the patients. The study demonstrated that each year of age increased the estimated risk of dementia in PD patients by 9% (OR=1.09; 95%CI: 1.01-1.17. CONCLUSION: There was no evidence to correlate the presence of metabolic syndrome with the risk of dementia that was associated with PD. The study confirmed that dementia in PD is age dependent and not related to disease duration.

  13. Age-associated changes in muscle activity during isometric contraction.

    Science.gov (United States)

    Arjunan, Sridhar P; Kumar, Dinesh K

    2013-04-01

    We investigated the effect of age on the complexity of muscle activity and the variance in the force of isometric contraction. Surface electromyography (sEMG) from biceps brachii muscle and force of contraction were recorded from 96 subjects (20-70 years of age) during isometric contractions. There was a reduction in the complexity of sEMG associated with aging. The relationship of age and complexity was approximated using a bilinear fit, with the average knee point at 45 years. There was an age-associated increase in the coefficient of variation (CoV) of the force of muscle contraction, and this increase was correlated with the decrease in complexity of sEMG (r(2) = 0.76). There was an age-associated increase in CoV and also a reduction in the complexity of sEMG. The correlation between these 2 factors can be explained based on the age-associated increase in motor unit density. Copyright © 2012 Wiley Periodicals, Inc.

  14. Aging and service wear of diesel engines used for emergency power at nuclear power stations

    International Nuclear Information System (INIS)

    Dingee, P.A.; Johnson, A.B.

    1985-01-01

    Aging and wear problems associated with emergency standby diesel generators are under study as part of the US Nuclear Regulatory Commission Nuclear Plant Aging Research program. Aging/wear factors identified in this study to date include chemical, mechanical, electrochemical, and bacterial mechanisms. The study also examines the potential of excessive engine testing as a cause of premature wear. To date, the results of this effort are not conclusive. An assessment of current wear mitigation measures such as engine maintenance and surveillance procedures suggests the need for their further development within the nuclear industry

  15. Antidepressant-Resistant Depression and Antidepressant-Associated Suicidal Behaviour: The Role of Underlying Bipolarity

    Directory of Open Access Journals (Sweden)

    Zoltan Rihmer

    2011-01-01

    Full Text Available The complex relationship between the use of antidepressants and suicidal behaviour is one of the hottest topics of our contemporary psychiatry. Based on the literature, this paper summarizes the author's view on antidepressant-resistant depression and antidepressant-associated suicidal behaviour. Antidepressant-resistance, antidepressant-induced worsening of depression, antidepressant-associated (hypomanic switches, mixed depressive episode, and antidepressant-associated suicidality among depressed patients are relatively most frequent in bipolar/bipolar spectrum depression and in children and adolescents. As early age at onset of major depressive episode and mixed depression are powerful clinical markers of bipolarity and the manic component of bipolar disorder (and possible its biological background shows a declining tendency with age antidepressant-resistance/worsening, antidepressant-induced (hypomanic switches and “suicide-inducing” potential of antidepressants seem to be related to the underlying bipolarity.

  16. Emotion regulation mediates age differences in emotions.

    Science.gov (United States)

    Yeung, Dannii Y; Wong, Carmen K M; Lok, David P P

    2011-04-01

    This study aimed at testing the proposition of socioemotional selectivity theory whether older people would use more antecedent-focused emotion regulatory strategies like cognitive reappraisal but fewer response-focused strategies like suppression. It also aimed at investigating the mediating role of emotion regulation on the relationship between age and emotions. The sample consisted of 654 younger and older adults aged between 18 and 64. Results showed that age was significantly associated with positive emotions and cognitive reappraisal. No difference was found in negative emotions and suppression between younger and older adults. Cognitive reappraisal partially mediated the effect of age on positive emotions. Findings of this study contribute to our understanding of the underlying mechanism of age variations in emotional experiences.

  17. Evolution of carbon distribution and mechanical properties during the static strain ageing of heavily drawn pearlitic steel wires

    International Nuclear Information System (INIS)

    Lamontagne, A.; Massardier, V.; Sauvage, X.; Kléber, X.; Mari, D.

    2016-01-01

    The static strain ageing of heavily cold-drawn pearlitic steel wires was investigated using both global techniques and local techniques (Atom Probe Tomography (APT)), in order to highlight how the cold-drawn destabilized microstructure returns to a more stable state during post-drawing treatments between 20 °C and 150 °C. The global techniques (thermoelectric power, differential scanning calorimetry) clearly showed that ageing occurs in three successive ageing stages and is due to a redistribution of the carbon atoms coming from the strain-induced cementite dissolution. The first ageing stage was unambiguously attributed to the carbon segregation to the defects, while the second and third stages were interpreted as being due to the precipitation of intermediate carbides (2nd stage) and cementite (3rd stage). The true strain was not found to significantly affect the ageing kinetics and mechanisms but appeared to play a role in the amount of carbon atoms involved in the different ageing stages. APT analyses confirmed that ageing is governed by the carbon depletion of strain-induced supersaturated ferrite. The strengthening mechanisms associated with the different ageing stages were also discussed.

  18. National Association of Area Agencies on Aging

    Science.gov (United States)

    National Association of Area Agencies on Aging Search Member Login Forgot Password? Menu ABOUT n4a Mission, Vision & Work AAAs & Title VI Aging Programs Membership Board of Directors Staff Contact ...

  19. Towards a sustainable healthy working life : associations between chronological age, functional age and work outcomes

    NARCIS (Netherlands)

    Koolhaas, Wendy; van der Klink, Jac J. L.; Groothoff, Johan W.; Brouwer, Sandra

    Background: The aims of this study were: (i) to determine the relation between chronological and functional age; (ii) to examine the association between chronological age and work outcomes; and (iii) to examine the association between functional age and work outcomes. An overview of the most

  20. Radiochemical aging of an epoxy network; Vieillissement radiochimique d'un reseau epoxyde

    Energy Technology Data Exchange (ETDEWEB)

    Devanne, Th

    2003-05-01

    This thesis is to give a better understanding of the radiochemical aging of a thermoset resin under gamma irradiation. The conditions of aging are gamma irradiation under air with a dose rate of 2 kGy/h at 120 C. The requested lifetime is four years, it means a dose of 70 MGy. The first step of this work was the choice of a resistive epoxy resin. This choice was made thanks to the literature data. The high glass transition temperature and the high amount of aromatic groups were the main criteria of the final choice. After this choice, thermal and mechanical properties were followed under thermal and radiochemical aging: i) under thermal aging, after 600 hours at 220 C, the glass transition temperature remained unchanged. But, from a mechanical point of view, properties at break dramatically decreased. This embrittlement was assigned to a critical oxidized layer. The thickness of this layer was estimated about 30 {mu}m. ii) the same kind of embrittlement was observed under radiochemical aging. Moreover, it appeared a decrease of the glass transition temperature when increasing the dose of irradiation. This indicates that the main degradation mechanism is chain scission under anaerobic atmosphere. We, then, proposed a mechanistic model associated with a kinetic model to predict the evolution of the glass transition temperature depending on the irradiation conditions. Parameters of the kinetic model were determined by solid NMR and ESR experiments. Comparison between experimental and calculated values at 120 C is satisfactory, a global good agreement was found. (author)

  1. Upregulation of Ih expressed in IB4-negative Aδ nociceptive DRG neurons contributes to mechanical hypersensitivity associated with cervical radiculopathic pain

    Science.gov (United States)

    Liu, Da-Lu; Lu, Na; Han, Wen-Juan; Chen, Rong-Gui; Cong, Rui; Xie, Rou-Gang; Zhang, Yu-Fei; Kong, Wei-Wei; Hu, San-Jue; Luo, Ceng

    2015-01-01

    Cervical radiculopathy represents aberrant mechanical hypersensitivity. Primary sensory neuron’s ability to sense mechanical force forms mechanotransduction. However, whether this property undergoes activity-dependent plastic changes and underlies mechanical hypersensitivity associated with cervical radiculopathic pain (CRP) is not clear. Here we show a new CRP model producing stable mechanical compression of dorsal root ganglion (DRG), which induces dramatic behavioral mechanical hypersensitivity. Amongst nociceptive DRG neurons, a mechanically sensitive neuron, isolectin B4 negative Aδ-type (IB4− Aδ) DRG neuron displays spontaneous activity with hyperexcitability after chronic compression of cervical DRGs. Focal mechanical stimulation on somata of IB4- Aδ neuron induces abnormal hypersensitivity. Upregulated HCN1 and HCN3 channels and increased Ih current on this subset of primary nociceptors underlies the spontaneous activity together with neuronal mechanical hypersensitivity, which further contributes to the behavioral mechanical hypersensitivity associated with CRP. This study sheds new light on the functional plasticity of a specific subset of nociceptive DRG neurons to mechanical stimulation and reveals a novel mechanism that could underlie the mechanical hypersensitivity associated with cervical radiculopathy. PMID:26577374

  2. Phase state of a Bi-43 wt % Sn superplastic alloy and its changes under the effect of external mechanical stresses and aging

    Science.gov (United States)

    Korshak, V. F.; Chushkina, R. A.; Shapovalov, Yu. A.; Mateichenko, P. V.

    2011-07-01

    Samples of a Bi-43 wt % Sn superplastic alloy have been studied by X-ray diffraction in the ascast state, after compression of as-cast samples to ˜70% on a hydraulic press, after aging in the as-cast and preliminarily compressed state, and using samples deformed under superplastic conditions. The X-ray diffraction studies have been carried out using a DRON-2.0 diffractometer in Cu Kα radiation. The samples aged and deformed under superplasticity conditions have been studied using electron-microprobe analysis in a JSM-820 scanning electron microscope equipped with a LINK AN/85S EDX system. It has been found that the initial structural-phase state of the alloy was amorphous-crystalline. Causes that lead to a change in this state upon deformation and aging are discussed. A conclusion is made that the superplasticity effect manifests itself against the background of processes that are stipulated by the tendency of the initially metastable alloy to phase equilibrium similarly to what is observed in the Sn-38 wt % Pb eutectic alloy studied earlier.

  3. Associations between Toddler-Age Communication and Kindergarten-Age Self-Regulatory Skills

    Science.gov (United States)

    Aro, Tuija; Laakso, Marja-Leena; Määttä, Sira; Tolvanen, Asko; Poikkeus, Anna-Maija

    2014-01-01

    Purpose: In this study, the authors aimed at gaining understanding on the associations of different types of early language and communication profiles with later self-regulation skills by using longitudinal data from toddler age to kindergarten age. Method: Children with early language profiles representing expressive delay, broad delay (i.e.,…

  4. The role of income and occupation in the association of education with healthy aging: results from a population-based, prospective cohort study.

    Science.gov (United States)

    White, Christine M; St John, Philip D; Cheverie, Madelon R; Iraniparast, Maryam; Tyas, Suzanne L

    2015-11-25

    The beneficial effects of higher education on healthy aging are generally accepted, but the mechanisms are less well understood. Education may influence healthy aging through improved employment opportunities that enhance feelings of personal control and reduce hazardous exposures, or through higher incomes that enable individuals to access better health care or to reside in better neighbourhoods. Income and occupation have not been explored extensively as potential mediators of the effect of education on healthy aging. This study investigates the role of income and occupation in the association between education and healthy aging including potential effect modification by gender. Logistic regression was used to explore the association of education, income (perceived income adequacy, life satisfaction with finances) and occupation (occupational prestige) with healthy aging five years later in 946 community-dwelling adults 65+ years from a population-based, prospective cohort study in Manitoba, Canada. Higher levels of education generally increased the likelihood of healthy aging. After adjusting for education, both income measures, but not occupation, predicted healthy aging among men; furthermore, the association between education and healthy aging was no longer significant. Income and occupation did not explain the significant association between education and healthy aging among women. Perceived income adequacy and life satisfaction with finances explained the beneficial effects of higher education on healthy aging among men, but not women. Identifying predictors of healthy aging and the mechanisms through which these factors exert their effects can inform strategies to maximize the likelihood of healthy aging.

  5. DC Electrical Ageing of XLPE under Hydrostatic Pressure

    Directory of Open Access Journals (Sweden)

    Fadila Benlizidia Lalam

    2017-01-01

    Full Text Available The experimental electrical ageing, of cross-linked polyethylene films 100 μm thick, was investigated under high hydrostatic pressure of 300 bar and at atmospheric pressure. The tests are conducted on direct current (dc for up to 1000 h ageing and at temperature of 70°C. The use of the Weibull statistic, with the estimation of confidence bounds at 90%, has shown that the hydrostatic pressure has a real effect on the lifetime. These lifetime data are qualitatively analyzed with the inverse power model. It was found that thermally activated process is able to describe the pressure effect on the electrical ageing of XLPE.

  6. Sonoelasticity to monitor mechanical changes during rigor and ageing.

    Science.gov (United States)

    Ayadi, A; Culioli, J; Abouelkaram, S

    2007-06-01

    We propose the use of sonoelasticity as a non-destructive method to monitor changes in the resistance of muscle fibres, unaffected by connective tissue. Vibrations were applied at low frequency to induce oscillations in soft tissues and an ultrasound transducer was used to detect the motions. The experiments were carried out on the M. biceps femoris muscles of three beef cattle. In addition to the sonoelasticity measurements, the changes in meat during rigor and ageing were followed by measurements of both the mechanical resistance of myofibres and pH. The variations of mechanical resistance and pH were compared to those of the sonoelastic variables (velocity and attenuation) at two frequencies. The relationships between pH and velocity or attenuation and between the velocity or attenuation and the stress at 20% deformation were highly correlated. We concluded that sonoelasticity is a non-destructive method that can be used to monitor mechanical changes in muscle fibers during rigor-mortis and ageing.

  7. KCNQ channels regulate age-related memory impairment.

    Directory of Open Access Journals (Sweden)

    Sonia Cavaliere

    Full Text Available In humans KCNQ2/3 heteromeric channels form an M-current that acts as a brake on neuronal excitability, with mutations causing a form of epilepsy. The M-current has been shown to be a key regulator of neuronal plasticity underlying associative memory and ethanol response in mammals. Previous work has shown that many of the molecules and plasticity mechanisms underlying changes in alcohol behaviour and addiction are shared with those of memory. We show that the single KCNQ channel in Drosophila (dKCNQ when mutated show decrements in associative short- and long-term memory, with KCNQ function in the mushroom body α/βneurons being required for short-term memory. Ethanol disrupts memory in wildtype flies, but not in a KCNQ null mutant background suggesting KCNQ maybe a direct target of ethanol, the blockade of which interferes with the plasticity machinery required for memory formation. We show that as in humans, Drosophila display age-related memory impairment with the KCNQ mutant memory defect mimicking the effect of age on memory. Expression of KCNQ normally decreases in aging brains and KCNQ overexpression in the mushroom body neurons of KCNQ mutants restores age-related memory impairment. Therefore KCNQ is a central plasticity molecule that regulates age dependent memory impairment.

  8. Pertussis in infancy and the association with respiratory and cognitive disorders at toddler age.

    Science.gov (United States)

    de Greeff, Sabine C; van Buul, Laura W; Westerhof, Anneke; Wijga, Alet H; van de Kassteele, Jan; Oostvogels, Bregje; van der Maas, Nicoline A T; Mooi, Frits R; de Melker, Hester E

    2011-10-26

    Pertussis in unvaccinated infants can run a severe course and is often accompanied by complications. In this pilot study, we studied whether there is an association between pertussis hospitalisation in infancy and, respiratory symptoms, growth and cognitive development in early childhood. A group of 89 children aged 13-45 months and hospitalised for laboratory confirmed pertussis within the first six months of their life were compared with 172 children without a history of pertussis. Risk ratios (RR) with 95% confidence intervals (CI) of the association between health outcomes and pertussis in infancy were calculated. Weight-for-length and length-for-age z-scores were calculated to investigate growth. Van Wiechen scores were compared to study cognitive development. Children with a history of pertussis in infancy had a greater chance on "asthma symptoms" (RR 2.8 95%CI 1.1-7.0) on toddler age and were more likely to report "respiratory infections" (RR 3.3 95%CI 1.6-6.6). In addition, children with a history of pertussis in infancy had significantly lower weight-for-height in the first 40 months of life. No significant differences in cognitive development were found. We found an association between severe pertussis in infancy and respiratory symptoms on toddler age. The mechanisms that may underlie this association require further investigation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Toward an understanding of mechanism of aging-induced oxidative stress in human mesenchymal stem cells.

    Science.gov (United States)

    Benameur, Laila; Charif, Naceur; Li, Yueying; Stoltz, Jean-François; de Isla, Natalia

    2015-01-01

    Under physiological conditions, there is a production of limited range of free radicals. However, when the cellular antioxidant defence systems, overwhelm and fail to reverse back the free radicals to their normal basal levels, there is a creation of a condition of redox disequilibrium termed "oxidative stress", which is implicated in a very wide spectrum of genetic, metabolic, and cellular responses. The excess of free radicals can, cause unfavourable molecular alterations to biomolecules through oxidation of lipids, proteins, RNA and DNA, that can in turn lead to mutagenesis, carcinogenesis, and aging. Mesenchymal stem cells (MSCs) have been proven to be a promising source of cells for regenerative medicine, and to be useful in the treatment of pathologies in which tissue damage is linked to oxidative stress. Moreover, MSCs appeared to efficiently manage oxidative stress and to be more resistant to oxidative insult than normal somatic cells, making them an interesting and testable model for the role of oxidative stress in the aging process. In addition, aging is accompanied by a progressive decline in stem cell function, resulting in less effective tissue homeostasis and repair. Also, there is an obvious link between intracellular reactive oxygen species levels and cellular senescence. To date, few studies have investigated the promotion of aging by oxidative stress on human MSCs, and the mechanism by which oxidative stress induce stem cell aging is poorly understood. In this context, the aim of this review is to gain insight the current knowledge about the molecular mechanisms of aging-induced oxidative stress in human MSCs.

  10. Nutritional status of children under the age five in Morocco

    International Nuclear Information System (INIS)

    El Rjimati, Arbi; El Menchawy, Imane; Baddou, Issâd; El Kari, Khalid; El Haloui, Noureddine; Aguenaou, Hassan; Rabi, Baha

    2014-01-01

    Full text: Introduction: In Morocco we live nutritional, demographic and epidemiological transition. These transitions affect the nutritional status of the population, especially that of children under five years of age. They also play a guiding role in the development of strategies to be implemented to improve the situation. Aim: To describe the evolution of the nutritional status of children under five years in Morocco over the past ten years. Methods: Two national surveys were conducted in 2004 and 2011. One of the objectives of these surveys is to assess the nutritional status of children aged less than five years compared to WHO standards. Results: The surveys that included 5737 children under 5 years in 2004 and 7271 in 2011 showed according to WHO standards, at the national level , a prevalence of underweight of 3.1 % ( weight / age 2 SD) 2.6 % of which are obese (BMI for age > 3 SD), whereas the proportion of children with overweight and obesity was 10.4 % in 2004. Discussion/conclusions: These studies show that acute malnutrition almost disappeared in Morocco, however prevalence of stunting remains high, overweight and obesity among children less than five years increased in the country. (author)

  11. A roadmap for the genetic analysis of renal aging.

    Science.gov (United States)

    Noordmans, Gerda A; Hillebrands, Jan-Luuk; van Goor, Harry; Korstanje, Ron

    2015-10-01

    Several studies show evidence for the genetic basis of renal disease, which renders some individuals more prone than others to accelerated renal aging. Studying the genetics of renal aging can help us to identify genes involved in this process and to unravel the underlying pathways. First, this opinion article will give an overview of the phenotypes that can be observed in age-related kidney disease. Accurate phenotyping is essential in performing genetic analysis. For kidney aging, this could include both functional and structural changes. Subsequently, this article reviews the studies that report on candidate genes associated with renal aging in humans and mice. Several loci or candidate genes have been found associated with kidney disease, but identification of the specific genetic variants involved has proven to be difficult. CUBN, UMOD, and SHROOM3 were identified by human GWAS as being associated with albuminuria, kidney function, and chronic kidney disease (CKD). These are promising examples of genes that could be involved in renal aging, and were further mechanistically evaluated in animal models. Eventually, we will provide approaches for performing genetic analysis. We should leverage the power of mouse models, as testing in humans is limited. Mouse and other animal models can be used to explain the underlying biological mechanisms of genes and loci identified by human GWAS. Furthermore, mouse models can be used to identify genetic variants associated with age-associated histological changes, of which Far2, Wisp2, and Esrrg are examples. A new outbred mouse population with high genetic diversity will facilitate the identification of genes associated with renal aging by enabling high-resolution genetic mapping while also allowing the control of environmental factors, and by enabling access to renal tissues at specific time points for histology, proteomics, and gene expression. © 2015 The Authors. Aging Cell published by the Anatomical Society and John

  12. Effects of delaying transplanting on agronomic traits and grain yield of rice under mechanical transplantation pattern.

    Directory of Open Access Journals (Sweden)

    Qihua Liu

    Full Text Available A delay in the mechanical transplantation (MT of rice seedlings frequently occurs in Huanghuai wheat-rice rotation cropping districts of China, due to the late harvest of wheat, the poor weather conditions and the insufficiency of transplanters, missing the optimum transplanting time and causing seedlings to age. To identify how delaying transplanting rice affects the agronomic characteristics including the growth duration, photosynthetic productivity and dry matter remobilization efficiency and the grain yield under mechanical transplanting pattern, an experiment with a split-plot design was conducted over two consecutive years. The main plot includes two types of cultivation: mechanical transplanting and artificial transplanting (AT. The subplot comprises four japonica rice cultivars. The results indicate that the rice jointing, booting, heading and maturity stages were postponed under MT when using AT as a control. The tiller occurrence number, dry matter weight per tiller, accumulative dry matter for the population, leaf area index, crop growth rate, photosynthetic potential, and dry matter remobilization efficiency of the leaf under MT significantly decreased compared to those under AT. In contrast, the reduction rate of the leaf area during the heading-maturity stage was markedly enhanced under MT. The numbers of effective panicles and filled grains per panicle and the grain yield significantly decreased under MT. A significant correlation was observed between the dry matter production, remobilization and distribution characteristics and the grain yield. We infer that, as with rice from old seedlings, the decrease in the tiller occurrence, the photosynthetic productivity and the assimilate remobilization efficiency may be important agronomic traits that are responsible for the reduced grain yield under MT.

  13. Polarization sensitive changes in the human macula associated with normal aging and age-related macular degeneration

    Science.gov (United States)

    VanNasdale, Dean Allan, Jr.

    2011-12-01

    The human macula occupies a relatively small, but crucial retinal area, as it is the location responsible for our most acute spatial vision and best color discrimination. Localizing important landmarks in the retina is difficult even in normal eyes where morphological inter-individual variability is high. This becomes even more challenging in the presence of sight-threatening pathology. With respect to the human macula, there remains a significant gap in the understanding of normal structure and function. Even less is known about the pathological mechanisms that occur in sight-threatening diseases including age-related macular degeneration. Because relatively little is known about normal aging changes, it is also difficult to differentiate those changes from changes associated with retinal disease. To better understand normal and pathological changes in the macula, imaging techniques using specific optical signatures are required. Structural features in the macula can be distinguished based on their intrinsic properties using specific light/tissue interactions. Because of the high degree of structural regularity in the macula, polarization sensitive imaging is potentially a useful tool for evaluating the morphology and integrity of the cellular architecture for both normal individuals and those affected by disease. In our investigations, we used polarization sensitive imaging to determining normal landmarks that are important clinically and for research investigations. We found that precision and accuracy in localizing the central macula was greatly improved through the use of polarization sensitive imaging. We also found that specific polarization alterations can be used to demonstrate systematic changes as a function of age, disproportionately affecting the central macular region. When evaluating patients with age-related macular degeneration, we found that precision and accuracy of localizing the central macula was also improved, even when significant pathology

  14. Nonlinear Dynamic Analysis of Telescopic Mechanism for Truss Structure Bridge Inspection Vehicle Under Pedestrian Excitation

    Directory of Open Access Journals (Sweden)

    Wenwen Sui

    Full Text Available Abstract Nonlinear dynamic analysis of an axially moving telescopic mechanism for truss structure bridge inspection vehicle under pedestrian excitation is carried out. A biomechanically inspired inverted-pendulum model is utilized to simplify the pedestrian. The nonlinear equations of motion for the beam-pedestrian system are derived using the Hamilton's principle. The equations are transformed into two ordinary differential equations by applying the Galerkin's method at the first two orders. The solutions to the equations are acquired by using the Newmark-β method associated with the Newton-Raphson method. The time-dependent feature of the eigenfunctions for the two beams are taken into consideration in the solutions. Accordingly, the equations of motion for a simplified system, in which the pedestrian is regarded as moving cart, are given. In the numerical examples, dynamic responses of the telescopic mechanism in eight conditions of different beam-telescoping and pedestrian-moving directions are simulated. Comparisons between the vibrations of the beams under pedestrian excitation and corresponding moving cart are carried out to investigate the influence of the pedestrian excitation on the telescopic mechanism. The results show that the displacement of the telescopic mechanism under pedestrian excitation is smaller than that under moving cart especially when the pedestrian approaches the beams end. Additionally, compared with moving cart, the pedestrian excitation can effectively strengthen the vibration when the beam extension is small or when the pedestrian is close to the beams end.

  15. Amygdala functional connectivity is associated with locus of control in the context of cognitive aging.

    Science.gov (United States)

    Ren, Ping; Anthony, Mia; Chapman, Benjamin P; Heffner, Kathi; Lin, Feng

    2017-05-01

    Locus of control (LOC) measures the extent to which individuals perceive control over their lives. Those with a more "internal" LOC feel self-sufficient and able to determine important aspects of their own future, while those with a more "external" LOC feel that their lives are governed by events beyond their control. Reduced internal LOC and increased external LOC have been found in cognitive disorders, but the neural substrates of these control perceptions are yet unknown. In the present study, we explored the relationship between amygdala functional connectivity and LOC in 18 amnestic mild cognitive impairment (MCI) and age-, sex-, and education-matched, 22 cognitively healthy controls (HC). Participants completed cognitive challenge tasks (Stroop Word Color task and Dual 1-back) for 20min, and underwent resting-state functional magnetic resonance imaging immediately before and after the tasks. We found significantly lower internal LOC and higher external LOC in the MCI group than the HC group. Compared to HC, MCI group showed significantly stronger positive associations between internal LOC and baseline right amygdala connections (including right middle frontal gyrus and anterior cingulate cortex), and stronger negative associations between internal LOC and change of these right amygdala connections. Across all participants, external LOC explained the relationships between associations of another set of right amygdala connections (including middle cingulate cortex and right superior frontal gyrus), both at baseline and for change, and performance in the cognitive challenge tasks. Our findings indicate that the right amygdala networks might be critical in understanding the neural mechanisms underlying LOC's role in cognitive aging. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. The Importance of Specifying and Studying Causal Mechanisms in School-Based Randomised Controlled Trials: Lessons from Two Studies of Cross-Age Peer Tutoring

    Science.gov (United States)

    Morris, Stephen P.; Edovald, Triin; Lloyd, Cheryl; Kiss, Zsolt

    2016-01-01

    Based on the experience of evaluating 2 cross-age peer-tutoring interventions, we argue that researchers need to pay greater attention to causal mechanisms within the context of school-based randomised controlled trials. Without studying mechanisms, researchers are less able to explain the underlying causal processes that give rise to results from…

  17. Antioxidant Property of Jobelyn as the Possible Mechanism Underlying

    Directory of Open Access Journals (Sweden)

    Solomon Umukoro

    2013-01-01

    Full Text Available   Introduction: Amnesia or loss of memory is the cardinal hallmark of Alzheimer’s disease (AD, a progressive neurodegenerative disorder associated with ageing process. Although, AD had been discovered over a century ago, drugs which could cure or halt the progression of the disease are yet to see the light of the day. However, there has been a growing interest in the use of phytomedicines with multipronged mechanisms of action that could target various aspects of the pathologies of AD. Jobelyn (JB is a potent antioxidant African polyherbal formulation with active components that have been acclaimed to show neuroprotection. T his investigation was carried out to evaluate whether JB has anti-amnesic and antioxidant activities.   Methods: The alteration of alternation behavior in the Y-maze paradigm was utilized as the test for memory function in mice. The effect of JB on a cetylcholinesterase (AChE activity, malondialdehyde (MDA level and the concentrations of glutathione (GSH in the frontal cortex and hippocampus were assessed in rats as means of providing insight into the mechanism underlying its anti-amnesic activity. The animals were given JB (1, 2.5 or 5mg/kg, i.p. daily for 7 days before the biochemical assays or test for memory functions were carried out.   Results: JB was found to produce a significant increase in the level of alternation behavior compared with the control, suggesting anti-amnesic activity. Also, JB reversed the memory impairment induced by scopolamine, which further indicates anti-amnesic property. Furthermore, JB demonstrated a significant inhibition of MDA formation in the frontal cortex and hippocampus of rats, indicating antioxidant property. In addition, it increased the defense armory of the brain tissues, as it significantly increased the concentrations of GSH in the frontal cortex and hippocampus of rats. However, JB did not demonstrate any inhibitory effect against AChE activity in the frontal cortex and

  18. Sex on the brain! Associations between sexual activity and cognitive function in older age.

    Science.gov (United States)

    Wright, Hayley; Jenks, Rebecca A

    2016-03-01

    the relationship between cognition and sexual activity in healthy older adults is under-researched. A limited amount of research in this area has shown that sexual activity is associated with better cognition in older men. The current study explores the possible mediating factors in this association in men and women, and attempts to provide an explanation in terms of physiological influences on cognitive function. using newly available data from Wave 6 of the English Longitudinal Study of Ageing, the current study explored associations between sexual activity and cognition in adults aged 50-89 (n = 6,833). Two different tests of cognitive function were analysed: number sequencing, which broadly relates to executive function, and word recall, which broadly relates to memory. after adjusting for age, education, wealth, physical activity, depression, cohabiting, self-rated health, loneliness and quality of life, there were significant associations between sexual activity and number sequencing and recall in men. However, in women there was a significant association between sexual activity and recall, but not number sequencing. possible mediators of these associations (e.g. neurotransmitters) are discussed. The cross-sectional nature of the analysis is limiting, but provides a promising avenue for future explorations and longitudinal studies. The findings have implications for the promotion of sexual counselling in healthcare settings, where maintaining a healthy sex life in older age could be instrumental in improving cognitive function and well-being. © The Author 2016. Published by Oxford University Press on behalf of the British Geriatrics Society.

  19. Artificial ageing of tri-layer polyethylene film used as greenhouse cover under the effect of the temperature and the UV-A simultaneously

    International Nuclear Information System (INIS)

    Dehbi, Abdelkader; Bouaza, Amar; Hamou, Ahmed; Youssef, Boulos; Saiter, Jean Marc

    2010-01-01

    This study helps to understand the mechanism of artificial ageing of a tri-layer film made of low-density polyethylene (LDPE) 'Agrofilm' with additives (color dye, UV and IR stabilizers) used as greenhouse cover under the variations of the temperature with or without UV-A radiations. Ageing was monitored by observing the change of physical properties (free surface energy, color) mechanical and structural effects (Tensile tests, DSC, FTIR) during 5486 h (almost 8 months). The study shows that increase in the free surface energy is proportional to the temperature and that the increase is more pronounced when the film is subjected to the combined action of the temperature and the UV-A radiations. The mechanical tests reveal that both elongation at break and yield stress decrease with the ageing. The calorific curves exhibit two endothermic peaks of melting close together (100 o C and 110 o C) which means the presence in the film of at least two types of crystalline structures. From free surface energy results, the life time of these films under artificial conditions is estimated to 12 months when exposed to 40 o C but drops to 3 months and 18 days when exposed simultaneously to 50 o C and UV-A.

  20. Comparative Study of Hardening Mechanisms During Aging of a 304 Stainless Steel Containing α'-Martensite

    Science.gov (United States)

    Jeong, S. W.; Kang, U. G.; Choi, J. Y.; Nam, W. J.

    2012-09-01

    Strain aging and hardening behaviors of a 304 stainless steel containing deformation-induced martensite were investigated by examining mechanical properties and microstructural evolution for different aging temperature and time. Introduced age hardening mechanisms of a cold rolled 304 stainless steel were the additional formation of α'-martensite, hardening of α'-martensite, and hardening of deformed austenite. The increased amount of α'-martensite at an aging temperature of 450 °C confirmed the additional formation of α'-martensite as a hardening mechanism in a cold rolled 304 stainless steel. Additionally, the increased hardness in both α'-martensite and austenite phases with aging temperature proved that hardening of both α'-martensite and austenite phases would be effective as hardening mechanisms in cold rolled and aged 304 stainless steels. The results suggested that among hardening mechanisms, hardening of an α'-martensite phase, including the diffusion of interstitial solute carbon atoms to dislocations and the precipitation of fine carbide particles would become a major hardening mechanism during aging of cold rolled 304 stainless steels.

  1. Accelerated DNA Methylation Age: Associations with PTSD and Neural Integrity

    Science.gov (United States)

    Wolf, Erika J.; Logue, Mark W.; Hayes, Jasmeet P.; Sadeh, Naomi; Schichman, Steven A.; Stone, Annjanette; Salat, David H.; Milberg, William; McGlinchey, Regina; Miller, Mark W.

    2015-01-01

    Background Accumulating evidence suggests that post traumatic stress disorder (PTSD) may accelerate cellular aging and lead to premature morbidity and neurocognitive decline. Methods This study evaluated associations between PTSD and DNA methylation (DNAm) age using recently developed algorithms of cellular age by Horvath (2013) and Hannum et al. (2013). These estimates reflect accelerated aging when they exceed chronological age. We also examined if accelerated cellular age manifested in degraded neural integrity, indexed via diffusion tensor imaging. Results Among 281 male and female veterans of the conflicts in Iraq and Afghanistan, DNAm age was strongly related to chronological age (rs ~.88). Lifetime PTSD severity was associated with Hannum DNAm age estimates residualized for chronological age (β = .13, p= .032). Advanced DNAm age was associated with reduced integrity in the genu of the corpus callosum (β = −.17, p= .009) and indirectly linked to poorer working memory performance via this region (indirect β = − .05, p= .029). Horvath DNAm age estimates were not associated with PTSD or neural integrity. Conclusions Results provide novel support for PTSD-related accelerated aging in DNAm and extend the evidence base of known DNAm age correlates to the domains of neural integrity and cognition. PMID:26447678

  2. Energy metabolism and inflammation in brain aging and Alzheimer's disease.

    Science.gov (United States)

    Yin, Fei; Sancheti, Harsh; Patil, Ishan; Cadenas, Enrique

    2016-11-01

    The high energy demand of the brain renders it sensitive to changes in energy fuel supply and mitochondrial function. Deficits in glucose availability and mitochondrial function are well-known hallmarks of brain aging and are particularly accentuated in neurodegenerative disorders such as Alzheimer's disease. As important cellular sources of H 2 O 2 , mitochondrial dysfunction is usually associated with altered redox status. Bioenergetic deficits and chronic oxidative stress are both major contributors to cognitive decline associated with brain aging and Alzheimer's disease. Neuroinflammatory changes, including microglial activation and production of inflammatory cytokines, are observed in neurodegenerative diseases and normal aging. The bioenergetic hypothesis advocates for sequential events from metabolic deficits to propagation of neuronal dysfunction, to aging, and to neurodegeneration, while the inflammatory hypothesis supports microglia activation as the driving force for neuroinflammation. Nevertheless, growing evidence suggests that these diverse mechanisms have redox dysregulation as a common denominator and connector. An independent view of the mechanisms underlying brain aging and neurodegeneration is being replaced by one that entails multiple mechanisms coordinating and interacting with each other. This review focuses on the alterations in energy metabolism and inflammatory responses and their connection via redox regulation in normal brain aging and Alzheimer's disease. Interaction of these systems is reviewed based on basic research and clinical studies. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. [Chronic malnutrition among children under five years of age in the northern part of Côte d'Ivoire].

    Science.gov (United States)

    Aké-Tano, Odile; Tiembré, Issaka; Konan, Yao Eugène; Donnen, Philippe; Dagnan, Simplice N'cho; Dramaix, Michelle; Koffi, Kouamé; Diarra-Nama, Alimata Jeanne

    2010-01-01

    The malnutrition of children under five years of age constitutes a major public health problem in most developing countries. A cross-section study was carried in 2003 in the northern part of Côte d'Ivoire to determine the prevalence of chronic malnutrition and to identify risk factors among children under five years of age living in urban and rural areas of the northern part of Côte d'Ivoire. A total of 292 and 268 children under five years of age residing respectively in urban and rural areas were included in the study. Their median age was 24 months. Chronic malnutrition was more frequent in children from rural areas (39.9%) than in those living in urban areas (16.7%). Malnutrition was significantly associated with the type of food consumed by children under two years of age in urban areas, and it was strongly linked to emaciation of the mother and presence of childhood fever in rural areas. In light of these results, we advocate a healthy diet and adequate health status for the mother and child to improve the nutritional status of children. Moreover, these results need to be completed and complemented by further studies for more detailed information to contribute to a better definition of actions to fight efficiently against malnutrition among children of the northern part of Côte d'Ivoire.

  4. Identification of novel genes associated with renal tertiary lymphoid organ formation in aging mice.

    Science.gov (United States)

    Huang, Yuan; Caputo, Christina R; Noordmans, Gerda A; Yazdani, Saleh; Monteiro, Luiz Henrique; van den Born, Jaap; van Goor, Harry; Heeringa, Peter; Korstanje, Ron; Hillebrands, Jan-Luuk

    2014-01-01

    A hallmark of aging-related organ deterioration is a dysregulated immune response characterized by pathologic leukocyte infiltration of affected tissues. Mechanisms and genes involved are as yet unknown. To identify genes associated with aging-related renal infiltration, we analyzed kidneys from aged mice (≥20 strains) for infiltrating leukocytes followed by Haplotype Association Mapping (HAM) analysis. Immunohistochemistry revealed CD45+ cell clusters (predominantly T and B cells) in perivascular areas coinciding with PNAd+ high endothelial venules and podoplanin+ lymph vessels indicative of tertiary lymphoid organs. Cumulative cluster size increased with age (analyzed at 6, 12 and 20 months). Based on the presence or absence of clusters in male and female mice at 20 months, HAM analysis revealed significant associations with loci on Chr1, Chr2, Chr8 and Chr14 in male mice, and with loci on Chr4, Chr7, Chr13 and Chr14 in female mice. Wisp2 (Chr2) showed the strongest association (P = 5.00×10(-137)) in male mice; Ctnnbip1 (P = 6.42×10(-267)) and Tnfrsf8 (P = 5.42×10(-245)) (both on Chr4) showed the strongest association in female mice. Both Wisp2 and Ctnnbip1 are part of the Wnt-signaling pathway and the encoded proteins were expressed within the tertiary lymphoid organs. In conclusion, this study revealed differential lymphocytic infiltration and tertiary lymphoid organ formation in aged mouse kidneys across different inbred mouse strains. HAM analysis identified candidate genes involved in the Wnt-signaling pathway that may be causally linked to tertiary lymphoid organ formation.

  5. DE-NE0000724 - Research Performance Final Report - Investigation of Thermal Aging Effects on the Evolution of Microstructure and Mechanical Properties of Cast Duplex Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Ankem, Sreeramamurthy [University of Maryland, College Park, MD (United States); Perea, Daniel E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kolli, R. Prakash [University of Maryland, College Park, MD (United States); Mburu, Sarah [University of Maryland, College Park, MD (United States); Schwarm, Samuel C. [University of Maryland, College Park, MD (United States)

    2017-12-11

    This report details the research activities carried out under DOE-NEUP award number DE-NE0000724 concerning the evolution of structural and mechanical properties during thermal aging of CF–3 and CF–8 cast duplex stainless steels (CDSS). The overall objective of this project was to use state-of-the-art characterization techniques to elucidate trends and phenomena in the mechanical and structural evolution of cast duplex stainless steels (CDSS) during thermal aging. These steels are commonly used as structural materials in commercial light water nuclear power plants, undergoing aging for decades in operation as cooling water pipes, pump casings, valve bodies, etc. During extended exposure to these conditions, CDSS are known to undergo a change in mechanical properties resulting in a loss of ductility, i.e. embrittlement. While it is generally accepted that structural changes within the ferrite phase, such as decomposition into iron (Fe)-rich and chromium (Cr)-rich domains, lead to the bulk embrittlement of the steels, many questions remain as to the mechanisms of embrittlement at multiple length scales. This work is intended to shed insight into the atomic level composition changes, associated kinetic mechanisms, and effects of changing phase structure on micro- and nano-scale deformation that lead to loss of impact toughness and tensile ductility in these steels. In general, this project provides a route to answer some of these major questions using techniques such as 3-dimensional (3-D) atom probe tomography (APT) and real-microstructure finite element method (FEM) modeling, which were not readily available when these steels were originally selected for service in light water reactors. Mechanical properties evaluated by Charpy V-notch impact testing (CVN), tensile testing, and microhardness and nanohardness measurements were obtained for each condition and compared with the initial baseline properties to view trends in deformation behavior during aging

  6. Effect of Positive End-Expiratory Pressure on Central Venous Pressure in Patients under Mechanical Ventilation.

    Science.gov (United States)

    Shojaee, Majid; Sabzghabaei, Anita; Alimohammadi, Hossein; Derakhshanfar, Hojjat; Amini, Afshin; Esmailzadeh, Bahareh

    2017-01-01

    Finding the probable governing pattern of PEEP and CVP changes is an area of interest for in-charge physicians and researchers. Therefore, the present study was designed with the aim of evaluating the relationship between the mentioned pressures. In this quasi-experimental study, patients under mechanical ventilation were evaluated with the aim of assessing the effect of PEEP change on CVP. Non-trauma patients, over 18 years of age, who were under mechanical ventilation and had stable hemodynamics, with inserted CV line were entered. After gathering demographic data, patients underwent 0, 5, and 10 cmH 2 O PEEPs and the respective CVPs of the mentioned points were recorded. The relationship of CVP and PEEP in different cut points were measured using SPSS 21.0 statistical software. 60 patients with the mean age of 73.95 ± 11.58 years were evaluated (68.3% male). The most frequent cause of ICU admission was sepsis with 45.0%. 5 cmH 2 O increase in PEEP led to 2.47 ± 1.53 mean difference in CVP level. If the PEEP baseline is 0 at the time of 5 cmH 2 O increase, it leads to a higher raise in CVP compared to when the baseline is 5 cmH 2 O (2.47 ± 1.53 vs. 1.57 ± 1.07; p = 0.039). The relationship between CVP and 5 cmH 2 O (p = 0.279), and 10 cmH 2 O (p = 0.292) PEEP changes were not dependent on the baseline level of CVP. The findings of this study revealed the direct relationship between PEEP and CVP. Approximately, a 5 cmH 2 O increase in PEEP will be associated with about 2.5 cmH 2 O raise in CVP. When applying a 5 cmH 2 O PEEP increase, if the baseline PEEP is 0, it leads to a significantly higher raise in CVP compared to when it is 5 cmH 2 O (2.5 vs. 1.6). It seems that sex, history of cardiac failure, baseline CVP level, and hypertension do not have a significant effect in this regard.

  7. Effect of Positive End-Expiratory Pressure on Central Venous Pressure in Patients under Mechanical Ventilation

    Directory of Open Access Journals (Sweden)

    Majid Shojaee

    2016-12-01

    Full Text Available Introduction: Finding the probable governing pattern of PEEP and CVP changes is an area of interest for in-charge physicians and researchers. Therefore, the present study was designed with the aim of evaluating the relationship between the mentioned pressures. Methods: In this quasi-experimental study, patients under mechanical ventilation were evaluated with the aim of assessing the effect of PEEP change on CVP. Non-trauma patients, over 18 years of age, who were under mechanical ventilation and had stable hemodynamics, with inserted CV line were entered. After gathering demographic data, patients underwent 0, 5, and 10 cmH2O PEEPs and the respective CVPs of the mentioned points were recorded. The relationship of CVP and PEEP in different cut points were measured using SPSS 21.0 statistical software. Results: 60 patients with the mean age of 73.95 ± 11.58 years were evaluated (68.3% male. The most frequent cause of ICU admission was sepsis with 45.0%. 5 cmH2O increase in PEEP led to 2.47 ± 1.53 mean difference in CVP level. If the PEEP baseline is 0 at the time of 5 cmH2O increase, it leads to a higher raise in CVP compared to when the baseline is 5 cmH2O (2.47 ± 1.53 vs. 1.57 ± 1.07; p = 0.039. The relationship between CVP and 5 cmH2O (p = 0.279, and 10 cmH2O (p = 0.292 PEEP changes were not dependent on the baseline level of CVP. Conclusion: The findings of this study revealed the direct relationship between PEEP and CVP. Approximately, a 5 cmH2O increase in PEEP will be associated with about 2.5 cmH2O raise in CVP. When applying a 5 cmH2O PEEP increase, if the baseline PEEP is 0, it leads to a significantly higher raise in CVP compared to when it is 5 cmH2O (2.5 vs. 1.6. It seems that sex, history of cardiac failure, baseline CVP level, and hypertension do not have a significant effect in this regard.

  8. Electrically and thermally activated ageing mechanisms in metallised polymer film capacitors

    International Nuclear Information System (INIS)

    Lee, Yuen Pen

    2001-01-01

    This dissertation describes a combined computational and experimental study to understand the fundamental electrostatic, thermal, electromagnetic, and discharge related processes during the ageing of metallised polymer film capacitors. In the event of internal breakdowns, these capacitors are capable of 'self-healing' through a controlled isolation of defects on the electrode surfaces by mosaic patterning the electrode. The objective of this project is to develop viable computer models to unravel electrothermally activated ageing processes in capacitors. To provide the necessary validation to any capacitor models developed, our work is supported by comprehensive experiments including industrial standard accelerated life tests and associated breakdown damage analyses of tested capacitors. These have enabled an empirical identification of main factors affecting the reliability and lifetime of capacitors. Relevant raw data and the qualitative picture enabled by these data are crucial to the development and refinement of viable computational models of capacitors. Given the complexity of ageing processes, it is both very difficult and unnecessary to develop a one-for-all model that describes indiscriminately all relevant processes. The approach adapted in this work has been to prioritise key ageing processes and modularise each process with its own computer model. The overall picture of capacitor ageing can then be unravelled by integrating all modules together. For instance, the fine geometrical features of the electrode mosaic pattern and the capacitor's laminated structure have been assessed through a concept of field intensification using a 2D electrostatic finite element computation. With fine geometrical features accounted for by the field intensification concept, fast electric events in capacitors can be simulated using a simple equivalent circuit model. Similar assessment of heat transfer has led to an equally efficient modelling of thermal events in capacitors

  9. DNA under Force: Mechanics, Electrostatics, and Hydration

    Directory of Open Access Journals (Sweden)

    Jingqiang Li

    2015-02-01

    Full Text Available Quantifying the basic intra- and inter-molecular forces of DNA has helped us to better understand and further predict the behavior of DNA. Single molecule technique elucidates the mechanics of DNA under applied external forces, sometimes under extreme forces. On the other hand, ensemble studies of DNA molecular force allow us to extend our understanding of DNA molecules under other forces such as electrostatic and hydration forces. Using a variety of techniques, we can have a comprehensive understanding of DNA molecular forces, which is crucial in unraveling the complex DNA functions in living cells as well as in designing a system that utilizes the unique properties of DNA in nanotechnology.

  10. Aging considerations for PWR [pressurized water reactor] control rod drive mechanisms and reactor internals

    International Nuclear Information System (INIS)

    Ware, A.G.

    1988-01-01

    This paper describes age-related degradation mechanisms affecting life extension of pressurized water reactor control rod drive mechanisms and reactor internals. The major sources of age-related degradation for control rod drive mechanisms are thermal transients such as plant heatups and cooldowns, latchings and unlatchings, long-term aging effects on electrical insulation, and the high temperature corrosive environment. Flow induced loads, the high-temperature corrosive environment, radiation exposure, and high tensile stresses in bolts all contribute to aging related degradation of reactor internals. Another problem has been wear and fretting of instrument guide tubes. The paper also discusses age-related failures that have occurred to date in pressurized water reactors

  11. A roadmap for the genetic analysis of renal aging

    Science.gov (United States)

    Noordmans, Gerda A; Hillebrands, Jan-Luuk; van Goor, Harry; Korstanje, Ron

    2015-01-01

    Several studies show evidence for the genetic basis of renal disease, which renders some individuals more prone than others to accelerated renal aging. Studying the genetics of renal aging can help us to identify genes involved in this process and to unravel the underlying pathways. First, this opinion article will give an overview of the phenotypes that can be observed in age-related kidney disease. Accurate phenotyping is essential in performing genetic analysis. For kidney aging, this could include both functional and structural changes. Subsequently, this article reviews the studies that report on candidate genes associated with renal aging in humans and mice. Several loci or candidate genes have been found associated with kidney disease, but identification of the specific genetic variants involved has proven to be difficult. CUBN, UMOD, and SHROOM3 were identified by human GWAS as being associated with albuminuria, kidney function, and chronic kidney disease (CKD). These are promising examples of genes that could be involved in renal aging, and were further mechanistically evaluated in animal models. Eventually, we will provide approaches for performing genetic analysis. We should leverage the power of mouse models, as testing in humans is limited. Mouse and other animal models can be used to explain the underlying biological mechanisms of genes and loci identified by human GWAS. Furthermore, mouse models can be used to identify genetic variants associated with age-associated histological changes, of which Far2, Wisp2, and Esrrg are examples. A new outbred mouse population with high genetic diversity will facilitate the identification of genes associated with renal aging by enabling high-resolution genetic mapping while also allowing the control of environmental factors, and by enabling access to renal tissues at specific time points for histology, proteomics, and gene expression. PMID:26219736

  12. Telomere in Aging and Age-Related Diseases

    Directory of Open Access Journals (Sweden)

    Anna Meiliana

    2017-12-01

    Full Text Available BACKGROUND: The number of elderly population in the world keep increasing. In their advanced ages, many elderly face years of disability because of multiple chronic diseases, frailty, making them lost their independence. Consequently, this could have impacts on social and economic stability. A huge challenge has been sent for biomedical researchers to compress or at least eliminate this period of disability and increase the health span. CONTENT: Over the past decades, many studies of telomere biology have demonstrated that telomeres and telomere-associated proteins are implicated in human diseases. Accelerated telomere erosion was clearly correlated with a pack of metabolic and inflammatory diseases. Critically short telomeres or the unprotected end, are likely to form telomeric fusion, generating genomic instability, the cornerstone for carcinogenesis. Enlightening how telomeres involved in the mechanisms underlying the diseases’ pathogenesis was expected to uncover new molecular targets for any important diagnosis or therapeutic implications. SUMMARY: Telomere shortening was foreseen as an imporant mechanism to supress tumor by limiting cellular proliferative capacity by regulating senescence check point activation. Many human diseases and carcinogenesis are causally related to defective telomeres, asserting the importance of telomeres sustainment. Thus, telomere length assessment might serve as an important tool for clinical prognostic, diagnostic, monitoring and management. KEYWORDS: telomerase, cellular senescence, aging, cancer

  13. The Physical Mechanism of Frictional Aging Revealed by Nanoindentation Creep

    Science.gov (United States)

    Thom, C.; Carpick, R. W.; Goldsby, D. L.

    2017-12-01

    A classical observation from rock friction experiments is that friction increases linearly with the logarithm of the time of stationary contact, a phenomenon sometimes referred to as aging. Aging is most often attributed to an increase in the real area of contact due to asperity creep. However, recent atomic force microscopy (AFM) experiments and molecular dynamics simulations suggest that time-dependent siloxane (Si—O—Si) bonding gives rise to aging in silica-silica contacts in the absence of plastic deformation. Determining whether an increase in contact `quantity' (due to creep), contact `quality' (due to chemical bonding), or another unknown mechanism causes aging is a challenging experimental task, despite its importance for developing a physical basis for rate and state friction laws. An intriguing observation is that aging is absent in friction experiments on quartz rocks and gouge at humidities water on asperity creep (via hydrolytic weakening) or on the adhesive strength of contacts. To discern between these possibilities, we have conducted nanoindentation experiments on single crystals of quartz to measure their indentation hardness and creep behavior at humidities of 2% to 50%, and in vacuum. Samples were loaded at 1000 mN/s to a peak load of 15, 40, or 400 mN, which was then held constant for 10 s. After the peak load is reached, the tip sinks into the material with time due to creep of the indentation contact. Our experiments reveal that there is no effect of varying humidity on either indentation hardness or indentation creep behavior over the full range of humidities investigated. If asperity creep were the dominant mechanism of frictional aging for quartz in the experiments cited above, then significant increases in hardness and decreases in the growth rate of indentation contacts at low humidities is expected, in stark contrast with our nanoindentation data. Our experiments indicate that asperity creep cannot be the cause of aging in quartz

  14. The slippery slope of hematopoietic stem cell aging.

    Science.gov (United States)

    Wahlestedt, Martin; Bryder, David

    2017-12-01

    The late stages of life, in most species including humans, are associated with a decline in the overall maintenance and health of the organism. This applies also to the hematopoietic system, where aging is not only associated with an increased predisposition for hematological malignancies, but also identified as a strong comorbidity factor for other diseases. Research during the last two decades has proposed that alterations at the level of hematopoietic stem cells (HSCs) might be a root cause for the hematological changes observed with age. However, the recent realization that not all HSCs are alike with regard to fundamental stem cell properties such as self-renewal and lineage potential has several implications for HSC aging, including the synchrony and the stability of the aging HSC state. To approach HSC aging from a clonal perspective, we recently took advantage of technical developments in cellular barcoding and combined this with the derivation of induced pluripotent stem cells (iPSCs). This allowed us to selectively approach HSCs functionally affected by age. The finding that such iPSCs were capable of fully regenerating multilineage hematopoiesis upon morula/blastocyst complementation provides compelling evidence that many aspects of HSC aging can be reversed, which indicates that a central mechanism underlying HSC aging is a failure to uphold the epigenomes associated with younger age. Here we discuss these findings in the context of the underlying causes that might influence HSC aging and the requirements and prospects for restoration of the aging HSC epigenome. Copyright © 2017 ISEH – Society for Hematology and Stem Cells. Published by Elsevier Inc. All rights reserved.

  15. Pathological mechanisms underlying single large‐scale mitochondrial DNA deletions

    Science.gov (United States)

    Rocha, Mariana C.; Rosa, Hannah S.; Grady, John P.; Blakely, Emma L.; He, Langping; Romain, Nadine; Haller, Ronald G.; Newman, Jane; McFarland, Robert; Ng, Yi Shiau; Gorman, Grainne S.; Schaefer, Andrew M.; Tuppen, Helen A.; Taylor, Robert W.

    2018-01-01

    Objective Single, large‐scale deletions in mitochondrial DNA (mtDNA) are a common cause of mitochondrial disease. This study aimed to investigate the relationship between the genetic defect and molecular phenotype to improve understanding of pathogenic mechanisms associated with single, large‐scale mtDNA deletions in skeletal muscle. Methods We investigated 23 muscle biopsies taken from adult patients (6 males/17 females with a mean age of 43 years) with characterized single, large‐scale mtDNA deletions. Mitochondrial respiratory chain deficiency in skeletal muscle biopsies was quantified by immunoreactivity levels for complex I and complex IV proteins. Single muscle fibers with varying degrees of deficiency were selected from 6 patient biopsies for determination of mtDNA deletion level and copy number by quantitative polymerase chain reaction. Results We have defined 3 “classes” of single, large‐scale deletion with distinct patterns of mitochondrial deficiency, determined by the size and location of the deletion. Single fiber analyses showed that fibers with greater respiratory chain deficiency harbored higher levels of mtDNA deletion with an increase in total mtDNA copy number. For the first time, we have demonstrated that threshold levels for complex I and complex IV deficiency differ based on deletion class. Interpretation Combining genetic and immunofluorescent assays, we conclude that thresholds for complex I and complex IV deficiency are modulated by the deletion of complex‐specific protein‐encoding genes. Furthermore, removal of mt‐tRNA genes impacts specific complexes only at high deletion levels, when complex‐specific protein‐encoding genes remain. These novel findings provide valuable insight into the pathogenic mechanisms associated with these mutations. Ann Neurol 2018;83:115–130 PMID:29283441

  16. Ageing in relation to skeletal muscle dysfunction: redox homoeostasis to regulation of gene expression.

    Science.gov (United States)

    Goljanek-Whysall, Katarzyna; Iwanejko, Lesley A; Vasilaki, Aphrodite; Pekovic-Vaughan, Vanja; McDonagh, Brian

    2016-08-01

    Ageing is associated with a progressive loss of skeletal muscle mass, quality and function-sarcopenia, associated with reduced independence and quality of life in older generations. A better understanding of the mechanisms, both genetic and epigenetic, underlying this process would help develop therapeutic interventions to prevent, slow down or reverse muscle wasting associated with ageing. Currently, exercise is the only known effective intervention to delay the progression of sarcopenia. The cellular responses that occur in muscle fibres following exercise provide valuable clues to the molecular mechanisms regulating muscle homoeostasis and potentially the progression of sarcopenia. Redox signalling, as a result of endogenous generation of ROS/RNS in response to muscle contractions, has been identified as a crucial regulator for the adaptive responses to exercise, highlighting the redox environment as a potentially core therapeutic approach to maintain muscle homoeostasis during ageing. Further novel and attractive candidates include the manipulation of microRNA expression. MicroRNAs are potent gene regulators involved in the control of healthy and disease-associated biological processes and their therapeutic potential has been researched in the context of various disorders, including ageing-associated muscle wasting. Finally, we discuss the impact of the circadian clock on the regulation of gene expression in skeletal muscle and whether disruption of the peripheral muscle clock affects sarcopenia and altered responses to exercise. Interventions that include modifying altered redox signalling with age and incorporating genetic mechanisms such as circadian- and microRNA-based gene regulation, may offer potential effective treatments against age-associated sarcopenia.

  17. Aging characteristic and mechanical properties of TiC/2618 composite

    Institute of Scientific and Technical Information of China (English)

    龙春光; 张厚安; 庞佑霞; 刘厚才

    2001-01-01

    TiC/2618 composite was prepared by XD method . The constituent and microstructure of the composite have been investigated by X-ray diffraction and TEM technique. The aging characteristics and mechanical properties at high and room temperatures were studied. The results show that: 1 ) it is possible to prepare multiple alloy matrix TiC/2618composite by XD method; 2) the TiC particles in TiC/2618 composite have the characteristics of fine size, clean appearance and a good bond with the matrix; 3) the aging law of the TiC/2618 composite has been changed by the addition of TiC particles. Two-peak value phenomenon has been observed when it was aged at 190 ℃; 4) TiC/2618 composite has better mechanical properties than those of the matrix both at room and high temperatures.

  18. Determinants Of Under Nutrition Among School Age Children In A ...

    African Journals Online (AJOL)

    Background: Malnutrition is a major public health concern affecting a significant number of school age children influencing their health, growth and development, and school academic performance. Objective: To establish the determinants of under nutrition among school age children between 6-12 years in a low-income ...

  19. Turing mechanism underlying a branching model for lung morphogenesis.

    Science.gov (United States)

    Xu, Hui; Sun, Mingzhu; Zhao, Xin

    2017-01-01

    The mammalian lung develops through branching morphogenesis. Two primary forms of branching, which occur in order, in the lung have been identified: tip bifurcation and side branching. However, the mechanisms of lung branching morphogenesis remain to be explored. In our previous study, a biological mechanism was presented for lung branching pattern formation through a branching model. Here, we provide a mathematical mechanism underlying the branching patterns. By decoupling the branching model, we demonstrated the existence of Turing instability. We performed Turing instability analysis to reveal the mathematical mechanism of the branching patterns. Our simulation results show that the Turing patterns underlying the branching patterns are spot patterns that exhibit high local morphogen concentration. The high local morphogen concentration induces the growth of branching. Furthermore, we found that the sparse spot patterns underlie the tip bifurcation patterns, while the dense spot patterns underlies the side branching patterns. The dispersion relation analysis shows that the Turing wavelength affects the branching structure. As the wavelength decreases, the spot patterns change from sparse to dense, the rate of tip bifurcation decreases and side branching eventually occurs instead. In the process of transformation, there may exists hybrid branching that mixes tip bifurcation and side branching. Since experimental studies have reported that branching mode switching from side branching to tip bifurcation in the lung is under genetic control, our simulation results suggest that genes control the switch of the branching mode by regulating the Turing wavelength. Our results provide a novel insight into and understanding of the formation of branching patterns in the lung and other biological systems.

  20. A mini-overview of single muscle fibre mechanics: the effects of age, inactivity and exercise in animals and humans.

    Science.gov (United States)

    Jee, Hyunseok; Kim, Jong-Hee

    2017-09-05

    Many basic movements of living organisms are dependent on muscle function. Muscle function allows for the coordination and harmonious integrity of movement that is necessary for various biological processes. Gross and fine motor skills are both regulated at the micro-level (single muscle fibre level), controlled by neuronal regulation, and it is therefore important to understand muscle function at both micro- and macro-levels to understand the overall movement of living organisms. Single muscle mechanics and the cellular environment of muscles fundamentally allow for the harmonious movement of our bodies. Indeed, a clear understanding of the functionality of muscle at the micro-level is indispensable for explaining muscular function at the macro-(whole gross muscle) level. By investigating single muscle fibre mechanics, we can also learn how other factors such Ca2+ kinetics, enzyme activity and contractile proteins can contribute to muscle mechanics at the micro- and macro-levels. Further, we can also describe how aging affects the capacity of skeletal muscle cells, as well as how exercise can prevent aging-based sarcopenia and frailty. The purpose of this review is to introduce and summarise the current knowledge of single muscle fibre mechanics in light of aging and inactivity. We then describe how exercise mitigates negative muscle adaptations that occur under those circumstances. In addition, single muscle fibre mechanics in both animal and human models are discussed.

  1. Workshop on multifactor aging mechanisms and models

    Science.gov (United States)

    Agarwal, V. K.

    1992-10-01

    There have been considerable efforts to understand the aging and failure mechanisms of insulation in electrical systems. However, progress has been slow because of the complex nature of the subject particularly when dealing with multiple stresses e.g. electrical, thermal, mechanical, radiation, humidity and other environmental factors. When an insulating material is exposed to just one stress factor e.g. electric field, one must devise test(s) which are not only economically efficient and practical but which take into account the nature of electric field (ac, dc and pulsed), duration and level or field strength, and field configurations. Any additional stress factor(s) make the matrix of measurements and the understanding of resulting degradation processes more complex, time consuming and expensive.

  2. Does white matter structure or hippocampal volume mediate associations between cortisol and cognitive ageing?

    Science.gov (United States)

    Cox, Simon R.; MacPherson, Sarah E.; Ferguson, Karen J.; Royle, Natalie A.; Maniega, Susana Muñoz; Hernández, Maria del C. Valdés; Bastin, Mark E.; MacLullich, Alasdair M.J.; Wardlaw, Joanna M.; Deary, Ian J.

    2015-01-01

    Elevated glucocorticoid (GC) levels putatively damage specific brain regions, which in turn may accelerate cognitive ageing. However, many studies are cross-sectional or have relatively short follow-up periods, making it difficult to relate GCs directly to changes in cognitive ability with increasing age. Moreover, studies combining endocrine, MRI and cognitive variables are scarce, measurement methods vary considerably, and formal tests of the underlying causal hypothesis (cortisol → brain → cognition) are absent. In this study, 90 men, aged 73 years, provided measures of fluid intelligence, processing speed and memory, diurnal and reactive salivary cortisol and two measures of white matter (WM) structure (WM hyperintensity volume from structural MRI and mean diffusivity averaged across 12 major tracts from diffusion tensor MRI), hippocampal volume, and also cognitive ability at age 11. We tested whether negative relationships between cognitive ageing differences (over more than 60 years) and salivary cortisol were significantly mediated by WM and hippocampal volume. Significant associations between reactive cortisol at 73 and cognitive ageing differences between 11 and 73 (r = −.28 to −.36, p cognition associations (cognitive ageing differences from childhood to the early 70s, partly via brain WM structure. PMID:26298692

  3. Push-and-stick mechanism for charged and excited small cluster emission under ion bombardment

    International Nuclear Information System (INIS)

    Bitensky, I.S.; Parilis, E.S.; Wojciechowski, I.A.

    1992-01-01

    The mechanism for the formation, excitation and ionization of small clusters emitted under ion bombardment is discussed. It is shown that the increased degree of ionization for the transition metal dimers, trimers and tetramers can be explained by the existence of an additional effective channel for their formation, namely the associative ionization process. A simple estimate shows that the sticking together of a fast cascade atom and the pushed out surface atom is 30-40 times more effective for dimer formation, than the recombination of two fast atoms. This push-and-stick mechanism of cluster formation could also be effective for the formation of trimers and tetramers. (orig.)

  4. Planning bridges the intention-behaviour gap: age makes a difference and strategy use explains why.

    Science.gov (United States)

    Reuter, Tabea; Ziegelmann, Jochen P; Wiedemann, Amelie U; Lippke, Sonia; Schuz, Benjamin; Aiken, Leona S

    2010-09-01

    This study examines age-differential association patterns between intentions, planning and physical activity in young and middle-aged individuals. The effectiveness of planning to bridge the intention-behaviour gap is assumed to increase with advancing age. We explore the use of behaviour change strategies that include selection, optimisation and compensation (SOC) as underlying mechanisms for age differences. In N = 265 employees of a national railway company (aged 19-64 years), intentions, planning, SOC strategy use and physical activity were assessed at baseline (Time 1) and again 1 month later (Time 2). Hypotheses were tested in two different path models. Age moderates the extent to which planning mediates the intention-behaviour relation due to an increasing strength of the planning-behaviour link. As a possible psychological mechanism for these age differences, we identified SOC strategy use as a mediator of the age by planning interaction effect on physical activity. These findings suggest differential mechanisms in behaviour regulation in young and middle-aged individuals.

  5. Habitually exercising older men do not demonstrate age-associated vascular endothelial oxidative stress.

    Science.gov (United States)

    Pierce, Gary L; Donato, Anthony J; LaRocca, Thomas J; Eskurza, Iratxe; Silver, Annemarie E; Seals, Douglas R

    2011-12-01

    We tested the hypothesis that older men who perform habitual aerobic exercise do not demonstrate age-associated vascular endothelial oxidative stress compared with their sedentary peers. Older exercising men (n=13, 62±2 years) had higher (Pexercise oxygen consumption (42±1 vs. 29±1 mL kg(-1) per minute) vs. sedentary men (n=28, 63±1 years). Brachial artery flow-mediated dilation (FMD), a measure of vascular endothelial function, was greater (Pexercising vs. sedentary older men (6.3±0.5 vs. 4.9±0.4%Δ) and not different than young controls (n=20, 25±1 years, 7.1±0.5%Δ). In vascular endothelial cells sampled from the brachial artery, nitrotyrosine, a marker of oxidative stress, was 51% lower in the exercising vs. sedentary older men (0.38±0.06 vs. 0.77±0.10 AU). This was associated with lower endothelial expression of the oxidant enzyme nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (p47(phox) subunit, 0.33±0.05 vs. 0.61±0.09 AU) and the redox-sensitive transcription factor nuclear factor kappa B (NFκB) (p65 subunit, 0.36±0.05 vs. 0.72±0.09 AU). Expression of the antioxidant enzyme manganese superoxide dismutase (SOD) (0.57±0.13 vs. 0.30±0.04 AU) and activity of endothelium-bound extracellular SOD were greater (6.4±0.5 vs. 5.0±0.6 U mL(-1) per minute) in the exercising men (both Pexercising older men. Older men who exercise regularly do not demonstrate vascular endothelial oxidative stress, and this may be a key molecular mechanism underlying their reduced risk of cardiovascular diseases. © 2011 The Authors. Aging Cell © 2011 Blackwell Publishing Ltd/Anatomical Society of Great Britain and Ireland.

  6. Molecular Mechanisms Responsible for Increased Vulnerability of the Ageing Oocyte to Oxidative Damage

    Science.gov (United States)

    Redgrove, Kate A.; McLaughlin, Eileen A.

    2017-01-01

    In their midthirties, women experience a decline in fertility, coupled to a pronounced increase in the risk of aneuploidy, miscarriage, and birth defects. Although the aetiology of such pathologies are complex, a causative relationship between the age-related decline in oocyte quality and oxidative stress (OS) is now well established. What remains less certain are the molecular mechanisms governing the increased vulnerability of the aged oocyte to oxidative damage. In this review, we explore the reduced capacity of the ageing oocyte to mitigate macromolecular damage arising from oxidative insults and highlight the dramatic consequences for oocyte quality and female fertility. Indeed, while oocytes are typically endowed with a comprehensive suite of molecular mechanisms to moderate oxidative damage and thus ensure the fidelity of the germline, there is increasing recognition that the efficacy of such protective mechanisms undergoes an age-related decline. For instance, impaired reactive oxygen species metabolism, decreased DNA repair, reduced sensitivity of the spindle assembly checkpoint, and decreased capacity for protein repair and degradation collectively render the aged oocyte acutely vulnerable to OS and limits their capacity to recover from exposure to such insults. We also highlight the inadequacies of our current armoury of assisted reproductive technologies to combat age-related female infertility, emphasising the need for further research into mechanisms underpinning the functional deterioration of the ageing oocyte. PMID:29312475

  7. Age-related associative deficits and the isolation effect.

    Science.gov (United States)

    Badham, Stephen P; Maylor, Elizabeth A

    2013-01-01

    If all but one of the items in a list are similar (e.g., all black except one red), memory for the different item is enhanced (the isolation effect). Older adults generally show similar or smaller isolation effects compared to young adults, which has been attributed to age-related deficits in associative memory whereby older adults are less able to associate an isolated stimulus to its isolating feature. Experiment 1 examined the isolation effect for isolation based on spatial position, modality and color; in Experiment 2, the criterion for isolation was the associative relation between stimuli. The results consistently showed no differences between young and older participants in the magnitude of the isolation effect. Whilst age deficits in associative memory may act to reduce the isolation effect in older adults, age deficits in self-initiated processing and inhibitory functionality may counteract this reduction by enhancing the isolation effect in older adults.

  8. Genetic variants in telomerase-related genes are associated with an older age at diagnosis in glioma patients: evidence for distinct pathways of gliomagenesis.

    Science.gov (United States)

    Walsh, Kyle M; Rice, Terri; Decker, Paul A; Kosel, Matthew L; Kollmeyer, Thomas; Hansen, Helen M; Zheng, Shichun; McCoy, Lucie S; Bracci, Paige M; Anderson, Erik; Hsuang, George; Wiemels, Joe L; Pico, Alexander R; Smirnov, Ivan; Molinaro, Annette M; Tihan, Tarik; Berger, Mitchell S; Chang, Susan M; Prados, Michael D; Lachance, Daniel H; Sicotte, Hugues; Eckel-Passow, Jeanette E; Wiencke, John K; Jenkins, Robert B; Wrensch, Margaret R

    2013-08-01

    Genome-wide association studies have implicated single nucleotide polymorphisms (SNPs) in 7 genes as glioma risk factors, including 2 (TERT, RTEL1) involved in telomerase structure/function. We examined associations of these 7 established glioma risk loci with age at diagnosis among patients with glioma. SNP genotype data were available for 2286 Caucasian glioma patients from the University of California, San Francisco (n = 1434) and the Mayo Clinic (n = 852). Regression analyses were performed to test for associations between "number of risk alleles" and "age at diagnosis," adjusted for sex and study site and stratified by tumor grade/histology where appropriate. Four SNPs were significantly associated with age at diagnosis. Carrying a greater number of risk alleles at rs55705857 (CCDC26) and at rs498872 (PHLDB1) was associated with younger age at diagnosis (P = 1.4 × 10(-22) and P = 9.5 × 10(-7), respectively). These SNPs are stronger risk factors for oligodendroglial tumors, which tend to occur in younger patients, and their association with age at diagnosis varied across tumor subtypes. In contrast, carrying more risk alleles at rs2736100 (TERT) and at rs6010620 (RTEL1) was associated with older age at diagnosis (P = 6.2 × 10(-4) and P = 2.5 × 10(-4), respectively). These SNPs are risk factors for all glioma grades/histologies, and their association with age at diagnosis was consistent across tumor subgroups. Carrying a greater number of risk alleles might be expected to decrease age at diagnosis. However, glioma susceptibility conferred by variation in telomerase-related genes did not follow this pattern. This supports the hypothesis that telomerase-related mechanisms of telomere maintenance are more associated with gliomas that develop later in life than those utilizing telomerase-independent mechanisms (ie, alternative lengthening of telomeres).

  9. Vascular Adventitia Calcification and Its Underlying Mechanism.

    Directory of Open Access Journals (Sweden)

    Na Li

    Full Text Available Previous research on vascular calcification has mainly focused on the vascular intima and media. However, we show here that vascular calcification may also occur in the adventitia. The purpose of this work is to help elucidate the pathogenic mechanisms underlying vascular calcification. The calcified lesions were examined by Von Kossa staining in ApoE-/- mice which were fed high fat diets (HFD for 48 weeks and human subjects aged 60 years and older that had died of coronary heart disease, heart failure or acute renal failure. Explant cultured fibroblasts and smooth muscle cells (SMCswere obtained from rat adventitia and media, respectively. After calcification induction, cells were collected for Alizarin Red S staining. Calcified lesions were observed in the aorta adventitia and coronary artery adventitia of ApoE-/-mice, as well as in the aorta adventitia of human subjects examined. Explant culture of fibroblasts, the primary cell type comprising the adventitia, was successfully induced for calcification after incubation with TGF-β1 (20 ng/ml + mineralization media for 4 days, and the phenotype conversion vascular adventitia fibroblasts into myofibroblasts was identified. Culture of SMCs, which comprise only a small percentage of all cells in the adventitia, in calcifying medium for 14 days resulted in significant calcification.Vascular calcification can occur in the adventitia. Adventitia calcification may arise from the fibroblasts which were transformed into myofibroblasts or smooth muscle cells.

  10. Energy Metabolism and Inflammation in Brain Aging and Alzheimer’s Disease

    Science.gov (United States)

    Yin, Fei; Sancheti, Harsh; Patil, Ishan; Cadenas, Enrique

    2016-01-01

    The high energy demand of the brain renders it sensitive to changes in energy fuel supply and mitochondrial function. Deficits in glucose availability and mitochondrial function are well-known hallmarks of brain aging and are particularly accentuated in neurodegenerative disorders such as Alzheimer’s disease. As important cellular sources of H2O2, mitochondrial dysfunction is usually associated with altered redox status. Bioenergetic deficits and chronic oxidative stress are both major contributors to cognitive decline associated with brain aging and Alzheimer’s disease. Neuroinflammatory changes, including microglial activation and production of inflammatory cytokines, are observed in neurodegenerative diseases and normal aging. The bioenergetic hypothesis advocates for sequential events from metabolic deficits to propagation of neuronal dysfunction, to aging, and to neurodegeneration, while the inflammatory hypothesis supports microglia activation as the driving force for neuroinflammation. Nevertheless, growing evidence suggests that these diverse mechanisms have redox dysregulation as a common denominator and connector. An independent view of the mechanisms underlying brain aging and neurodegeneration is being replaced by one that entails multiple mechanisms coordinating and interacting with each other. This review focuses on the alterations in energy metabolism and inflammatory responses and their connection via redox regulation in normal brain aging and Alzheimer’s disease. Interactions of these systems is reviewed based on basic research and clinical studies. PMID:27154981

  11. [Molecular mechanisms of autophagy in regulating renal aging and interventional effects of Chinese herbal medicine].

    Science.gov (United States)

    Tu, Yue; Sun, Wei; Chen, Di-Ping; Wan, Yi-Gang; Wu, Wei; Yao, Jian

    2016-11-01

    Aging is the gradual functional recession of the living tissues or organs caused by a variety of genetic and environmental factors together. Autophagy is a process of degrading cytoplasmic components mediated by lysosomes in eukaryotic cells. Kidney is a typical target organ of aging. Autophagy regulates renal aging. Decrease in autophagy can accelerate renal aging,whereas,increase in autophagy can delay renal aging. During the process of regulating renal aging,the mammalian target of rapamycin (mTOR) and its related signaling pathways including the adenosine monophosphate activated protein kinase (AMPK)/mTOR,the phosphatidylinositol 3-kinase (PI3K)/ serine-threonine kinase(Akt)/mTOR,the AMPK/silent information regulation 1 (Sirt1) and transforming growth factor β (TGF-β) play the important roles in renal aging. Regulating the key signaling molecules in these pathways in vivo can control renal aging. Some Chinese herbal medicine (CHM) and their extracts with the effects of nourishing kidney or activating stasis, such as Cordyceps sinensis, curcumin and resveratrol have the beneficial effects on renal aging and/or autophagy. Therefore,revealing the pharmacological effects of CHM in anti-renal aging based on the molecular mechanisms of autophagy will become one of the development trends in the future study. Copyright© by the Chinese Pharmaceutical Association.

  12. Amount of fear extinction changes its underlying mechanisms.

    Science.gov (United States)

    An, Bobae; Kim, Jihye; Park, Kyungjoon; Lee, Sukwon; Song, Sukwoon; Choi, Sukwoo

    2017-07-03

    There has been a longstanding debate on whether original fear memory is inhibited or erased after extinction. One possibility that reconciles this uncertainty is that the inhibition and erasure mechanisms are engaged in different phases (early or late) of extinction. In this study, using single-session extinction training and its repetition (multiple-session extinction training), we investigated the inhibition and erasure mechanisms in the prefrontal cortex and amygdala of rats, where neural circuits underlying extinction reside. The inhibition mechanism was prevalent with single-session extinction training but faded when single-session extinction training was repeated. In contrast, the erasure mechanism became prevalent when single-session extinction training was repeated. Moreover, ablating the intercalated neurons of amygdala, which are responsible for maintaining extinction-induced inhibition, was no longer effective in multiple-session extinction training. We propose that the inhibition mechanism operates primarily in the early phase of extinction training, and the erasure mechanism takes over after that.

  13. The Association Between P3 Amplitude at Age 11 and Criminal Offending at Age 23

    Science.gov (United States)

    Gao, Yu; Raine, Adrian; Venables, Peter H.; Mednick, Sarnoff A.

    2014-01-01

    Reduced P3 amplitude to targets is an information-processing deficit associated with adult antisocial behavior and may reflect dysfunction of the temporal-parietal junction. This study aims to examine whether this deficit precedes criminal offending. From a birth cohort of 1,795 children, 73 individuals who become criminal offenders at age 23 and 123 noncriminal individuals were assessed on P3 amplitude. The two groups did not differ on gender, ethnicity, and social adversity. P3 amplitude was measured over the temporal-parietal junction during a visual continuous performance task at age 11, together with antisocial behavior. Criminal convictions were assessed at age 23. Reduced P3 amplitude at age 11 was associated with increased antisocial behavior at age 11. Criminal offenders showed significantly reduced P3 amplitudes to target stimuli compared to controls. Findings remained significant after controlling for antisocial behavior and hyperactivity at age 11 and alcoholism at age 23. P3 deficits at age 11 are associated with adult crime at age 23, suggesting that reduced P3 may be an early neurobiological marker for cognitive and affective processes subserved by the temporal-parietal junction that place a child at risk for adult crime. PMID:22963083

  14. Undernutrition among children under 5 years of age in Yemen: Role of adequate childcare provided by adults under conditions of food insecurity.

    Science.gov (United States)

    Al-Sobaihi, Saber; Nakamura, Keiko; Kizuki, Masashi

    2016-01-01

    Objective: This study examined the associations between the adequacy of childcare provided by adult caretakers and childhood undernutrition in rural Yemen, independent of household wealth and food consumption. Methods: We analyzed data of 3,549 children under the age of 5 years living in rural areas of Yemen based on the 2013 Yemen Baseline Survey of Mother and Child Health. Nutritional status was evaluated by the presence of underweight, stunting, and wasting according to the World Health Organization child growth standards. The impact of childcare including leaving children alone, putting older children into labor force, and the use of antenatal care while pregnant on child undernutrition was assessed and adjusted for food consumption by children, household composition, demographic and educational background of caretakers, and household wealth. Results: The prevalence of underweight, stunting, and wasting was 46.2%, 62.6%, and 11.1%, respectively. Not leaving children alone, keeping children out of the labor force, and use of antenatal care were associated with a lower risk of underweight (odds ratio [OR] = 0.84, P = 0.016; OR = 0.84, P = 0.036; and OR = 0.85, P = 0.042) and stunting (OR = 0.80, P = 0.004; OR = 0.82, P = 0.024; and OR = 0.78, P = 0.003). After further adjustment for food consumption, the associations between adequate childcare indicators and lower odds of stunting remained significant (OR = 0.73, P = 0.025; OR = 0.72, P = 0.046; and OR = 0.76, P = 0.038). Conclusions: A marked prevalence of stunting among rural children in Yemen was observed. Adequate childcare by adult caretakers in families is associated with a lower incidence of underweight and stunting among children under 5 years of age. Promoting adequate childcare by adult household members is a feasible option for reducing undernutrition among children in rural Yemen.

  15. Chronological age and its impact on associative learning proficiency and brain structure in middle adulthood.

    Science.gov (United States)

    Diwadkar, Vaibhav A; Bellani, Marcella; Ahmed, Rizwan; Dusi, Nicola; Rambaldelli, Gianluca; Perlini, Cinzia; Marinelli, Veronica; Ramaseshan, Karthik; Ruggeri, Mirella; Bambilla, Paolo

    2016-01-15

    The rate of biological change in middle-adulthood is relatively under-studied. Here, we used behavioral testing in conjunction with structural magnetic resonance imaging to examine the effects of chronological age on associative learning proficiency and on brain regions that previous functional MRI studies have closely related to the domain of associative learning. Participants (n=66) completed a previously established associative learning paradigm, and consented to be scanned using structural magnetic resonance imaging. Age-related effects were investigated both across sub-groups in the sample (younger vs. older) and across the entire sample (using regression approaches). Chronological age had substantial effects on learning proficiency (independent of IQ and Education Level), with older adults showing a decrement compared to younger adults. In addition, decreases in estimated gray matter volume were observed in multiple brain regions including the hippocampus and the dorsal prefrontal cortex, both of which are strongly implicated in associative learning. The results suggest that middle adulthood may be a more dynamic period of life-span change than previously believed. The conjunctive application of narrowly focused tasks, with conjointly acquired structural MRI data may allow us to enrich the search for, and the interpretation of, age-related changes in cross-sectional samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. The suppression of ghrelin signaling mitigates age-associated thermogenic impairment

    Science.gov (United States)

    Aging is associated with severe thermogenic impairment, which contributes to obesity and diabetes in aging. We previously reported that ablation of the ghrelin receptor, growth hormone secretagogue receptor (GHS-R), attenuates age-associated obesity and insulin resistance. Ghrelin and obestatin are ...

  17. Age and gender differences in mechanically induced intraoral temporal summation and conditioned pain modulation in healthy subjects.

    Science.gov (United States)

    Khan, Junad; Korczeniewska, Olga; Benoliel, Rafael; Kalladka, Mythili; Eliav, Eli; Nasri-Heir, Cibelle

    2018-04-13

    The aim of this study was to investigate intraoral temporal summation (TS) and conditioned pain modulation (CPM) and compare the outcome with TS and CPM induced in the forearm. In addition, we aimed to study the effect of age and gender on intraoral and forearm TS and CPM. Mechanical stimulation was induced with # 5.46 von Frey filament applying 26 grams of force. A single stimulus, followed by a train of 30 successive stimuli, was applied intraorally and to the dominant forearm. CPM was assessed with the TS test as the painful stimulus and with immersion of the nondominant hand in a hot water bath as the conditioning stimulus. Gender was significantly associated with TS but not with CPM measures. Females had significantly lower mean TS measured in the face and in the dominant forearm compared with males. Age was significantly associated with CPM, but not with TS measures. In both sites examined, older patients had significantly lower mean CPM compared with younger patients. Mechanical TM elicited in the oral cavity can be used as test stimulus for CPM testing. Intraoral modulation, both TS and CPM, has an extent similar to that of the standard cutaneous extremity. TS was lower in females, and CPM was reduced with age. Copyright © 2018 Elsevier Inc. All rights reserved.

  18. Ageing degradation mechanisms in nuclear power plants: lessons learned from operating experience

    International Nuclear Information System (INIS)

    Bieth, M.; Zerger, B.; Duchac, A.

    2014-01-01

    This paper presents main results of a comprehensive study performed by the European Clearinghouse on Operating Experience Feedback of Nuclear Power Plants (NPP) with the support of IRSN (Institut de Surete Nucleaire et de Radioprotection) and GRS (Gesellschaft fuer Anlagen und Reaktorsicherheit mbH). Physical ageing mechanisms of Structures, Systems and Components (SSC) that eventually lead to ageing related systems and components failures at nuclear power plants were the main focus of this study. The analysis of ageing related events involved operating experience reported by NPP operators in France, Germany, USA and to the IAEA/NEA International Reporting System on operating experience for the past 20 years. A list of relevant ageing related events was populated. Each ageing related event contained in the list was analyzed and results of analysis were summarized for each ageing degradation mechanism which appeared to be the dominant contributor or direct cause. This paper provides insights into ageing related operating experience as well as recommendations to deal with the physical ageing of nuclear power plant SSC important to safety. (authors)

  19. Age- and gender-specific associations of napping duration with type 2 diabetes mellitus in a Chinese rural population: the RuralDiab study.

    Science.gov (United States)

    Liu, Ruihua; Li, Yuqian; Wang, Fang; Liu, Xiaotian; Zhou, Hao; Wang, Panpan; Fan, Jingjing; Xu, Fei; Yang, Kaili; Hu, Dongsheng; Bie, Ronghai; Wang, Chongjian

    2017-05-01

    The consistency and strength of the relationship between napping duration and type 2 diabetes mellitus (T2DM) remained uncertain, especially in the rural population. The purpose of this study was to explore the relationship between napping duration and T2DM in a Chinese rural population. A total of 12663 participants (4365 males and 8298 females) were derived from the RuralDiab study in China. Napping duration was obtained through a standardized questionnaire, and was divided into five categories: no napping (reference), 1∼, 31∼, 61∼, and ≥91 min. Fasting blood glucose was measured. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). A meta-analysis including seven studies was conducted to validate the result of the RuralDiab study. The crude and age-standardized prevalence of T2DM were 10.31% and 8.14%, respectively. Compared with no napping, the adjusted OR (95%CI) for napping duration ≥91 min was 1.23 (1.05-1.45). A similar relationship was found only in females aged 45-54 years, but not in males and other age group females. In addition, napping duration was associated with T2DM in a positive dose-dependent manner among females aged 45-54 years (P for trend napping duration compared with no napping was 1.28 (1.22-1.35). Longer napping duration is associated with higher risk of T2DM in the Chinese rural population, and this association varies across gender and age. Further multi-center prospective researches are needed to confirm the relationship and reveal underlying mechanisms. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Oscillatory Dynamics Underlying Perceptual Narrowing of Native Phoneme Mapping from 6 to 12 Months of Age.

    Science.gov (United States)

    Ortiz-Mantilla, Silvia; Hämäläinen, Jarmo A; Realpe-Bonilla, Teresa; Benasich, April A

    2016-11-30

    During the first months of life, human infants process phonemic elements from all languages similarly. However, by 12 months of age, as language-specific phonemic maps are established, infants respond preferentially to their native language. This process, known as perceptual narrowing, supports neural representation and thus efficient processing of the distinctive phonemes within the sound environment. Although oscillatory mechanisms underlying processing of native and non-native phonemic contrasts were recently delineated in 6-month-old infants, the maturational trajectory of these mechanisms remained unclear. A group of typically developing infants born into monolingual English families, were followed from 6 to 12 months and presented with English and Spanish syllable contrasts varying in voice-onset time. Brain responses were recorded with high-density electroencephalogram, and sources of event-related potential generators identified at right and left auditory cortices at 6 and 12 months and also at frontal cortex at 6 months. Time-frequency analyses conducted at source level found variations in both θ and γ ranges across age. Compared with 6-month-olds, 12-month-olds' responses to native phonemes showed smaller and faster phase synchronization and less spectral power in the θ range, and increases in left phase synchrony as well as induced high-γ activity in both frontal and left auditory sources. These results demonstrate that infants become more automatized and efficient in processing their native language as they approach 12 months of age via the interplay between θ and γ oscillations. We suggest that, while θ oscillations support syllable processing, γ oscillations underlie phonemic perceptual narrowing, progressively favoring mapping of native over non-native language across the first year of life. During early language acquisition, typically developing infants gradually construct phonemic maps of their native language in auditory cortex. It is well

  1. Age-related changes in overcoming proactive interference in associative memory: The role of PFC-mediated executive control processes at retrieval.

    Science.gov (United States)

    Dulas, Michael R; Duarte, Audrey

    2016-05-15

    Behavioral evidence has shown age-related impairments in overcoming proactive interference in memory, but it is unclear what underlies this deficit. Imaging studies in the young suggest overcoming interference may require several executive control processes supported by the ventrolateral prefrontal cortex (VLPFC) and dorsolateral PFC (DLPFC). The present functional magnetic resonance imaging (fMRI) study investigated whether age-related changes in dissociable executive control processes underlie deficits in overcoming proactive interference in associative memory during retrieval. Participants were tasked with remembering which associate (face or scene) objects were paired with most recently during study, under conditions of high or low proactive interference. Behavioral results demonstrated that, as interference increased, memory performance decreased similarly across groups, with slight associative memory deficits in older adults. Imaging results demonstrated that, across groups, left mid-VLPFC showed increasing activity with increasing interference, though activity did not distinguish correct from incorrect associative memory responses, suggesting this region may not directly serve in successful resolution of proactive interference, per se. Under conditions of high interference, older adults showed reduced associative memory accuracy effects in the DLPFC and anterior PFC. These results suggest that age-related PFC dysfunction may not be ubiquitous. Executive processes supported by ventral regions that detect mnemonic interference may be less affected than processes supported by dorsal and anterior regions that directly resolve interference. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Glia and zinc in ageing and Alzheimer’s disease: A mechanism for cognitive decline?

    Directory of Open Access Journals (Sweden)

    Sara eHancock

    2014-06-01

    Full Text Available Normal ageing is characterised by cognitive decline across a range of neurological functions, which are further impaired in Alzheimer’s disease (AD. Recently, alterations in zinc concentrations, particularly at the synapse, have emerged as a potential mechanism underlying the cognitive changes that occur in both ageing and AD. Zinc is now accepted as a potent neuromodulator, affecting a variety of signalling pathways at the synapse that are critical to normal cognition. While the focus has principally been on the neuron: zinc interaction, there is a growing literature suggesting that glia may also play a modulatory role in maintaining both zinc ion homeostasis and the normal function of the synapse. Indeed, zinc transporters have been demonstrated in glial cells where zinc has also been shown to have a role in signalling. Furthermore, there is increasing evidence that the pathogenesis of AD critically involves glial cells (such as astrocytes, which have been reported to contribute to amyloid-beta neurotoxicity. This review discusses the current evidence supporting a complex interplay of glia, zinc dyshomeostasis and synaptic function in ageing and AD.

  3. Potential importance of B cells in aging and aging-associated neurodegenerative diseases.

    Science.gov (United States)

    Biragyn, Arya; Aliseychik, Maria; Rogaev, Evgeny

    2017-04-01

    Our understanding of B cells as merely antibody producers is slowly changing. Alone or in concert with antibody, they control outcomes of seemingly different diseases such as cancer, rheumatoid arthritis, diabetes, and multiple sclerosis. While their role in activation of effector immune cells is beneficial in cancer but bad in autoimmune diseases, their immunosuppressive and regulatory subsets (Bregs) inhibit autoimmune and anticancer responses. These pathogenic and suppressive functions are not static and appear to be regulated by the nature and strength of inflammation. Although aging increases inflammation and changes the composition and function of B cells, surprisingly, little is known whether the change affects aging-associated neurodegenerative disease, such as Alzheimer's disease (AD). Here, by analyzing B cells in cancer and autoimmune and neuroinflammatory diseases, we elucidate their potential importance in AD and other aging-associated neuroinflammatory diseases.

  4. Age-related aspects of cutaneous wound healing: a mini-review.

    Science.gov (United States)

    Sgonc, Roswitha; Gruber, Johann

    2013-01-01

    As the aging population in developed countries is growing in both numbers and percentage, the medical, social, and economic burdens posed by nonhealing wounds are increasing. Hence, it is all the more important to understand the mechanisms underlying age-related impairments in wound healing. The purpose of this article is to give a concise overview of (1) normal wound healing, (2) alterations in aging skin that have an impact on wound repair, (3) alterations in the repair process of aged skin, and (4) general factors associated with old age that might impair wound healing, with a focus on the literature of the last 10 years. Copyright © 2012 S. Karger AG, Basel.

  5. Control of a perturbed under-actuated mechanical system

    KAUST Repository

    Zayane, Chadia; Laleg-Kirati, Taous-Meriem; Chemori, Ahmed

    2015-01-01

    In this work, the trajectory tracking problem for an under-actuated mechanical system in presence of unknown input disturbances is addressed. The studied inertia wheel inverted pendulum falls in the class of non minimum phase systems. The proposed

  6. Biochar may physically entrap nitrate during field aging or co-composting which become plant available under controlled conditions

    Science.gov (United States)

    Haider, Ghulam; Steffens, Diedrich; Müller, Christoph; Kammann, Claudia

    2017-04-01

    Conversion of organic biomass (agriculture/forestry residues) to biochar (BC) for carbon sequestration in soil to abate global warming has received much attention in recent years. However, apart from carbon sequestration, the incorporation of freshly produced biochars in agricultural soils have shown varying effects on soil-plant-moisture and nutrient interactions. It has been frequently reported that BC amendment may accelerate soil N transformations, reduce nitrate leaching, increase nutrient availability and soil fertility thereby increase crop yields by 10-15%. In addition, recent meta-studies suggested that BC-nitrogen (N) interactions in agricultural soils have the potential to reduce nitrous oxide (N2O) emissions by 50% with the underlying mechanisms not well understood. Also, mechanisms of BC-N sorption and desorption or plant availability of captured N in BC remain poorly understood. In this study we conducted two different experiments aiming (a) to understand the mechanism of nitrate capture by field aged (>3 years) BC (wood chip, pruning, bark and leaves (550-600°C)) and (b) to test the availability of captured nitrate by field-aged and composted BC to plants (quinoa, ryegrass) in a pot study under controlled conditions. Experiment (A): We hypothesized that N captured in the pores of BC may remain inaccessible to extraction solutions due to clogging of BC pores by the development of hydrophobic layer on BC surface following oxidation under field conditions. Therefore (i) physically breaking the structure or (ii) exerting under-pressure to water-immersed aged BC particles may allow extracting greater nitrate with the standard 2 M KCl method compared to intact particles. Study (A) encompassed 1) extraction from intact field-aged BC particles, 2) extraction after immersion in water and evacuation in vacutainers, 3) extraction after grinding of BC to powder and 4) prolonged shaking (48 hours at 80°C) of intact field aged BC particles and then extraction

  7. Genetic variants modify the effect of age on APOE methylation in the Genetics of Lipid Lowering Drugs and Diet Network study

    Science.gov (United States)

    Although apolipoprotein E (APOE) variants are associated with age related diseases, the underlying mechanism is unknown and DNA methylation may be a potential one. With methylation data, measured by the Infinium Human Methylation 450 array, from 993 participants (age ranging from 18 to 87 y) in the ...

  8. Older maternal age is associated with depression, anxiety, and stress symptoms in young adult female offspring.

    Science.gov (United States)

    Tearne, Jessica E; Robinson, Monique; Jacoby, Peter; Allen, Karina L; Cunningham, Nadia K; Li, Jianghong; McLean, Neil J

    2016-01-01

    The evidence regarding older parental age and incidence of mood disorder symptoms in offspring is limited, and that which exists is mixed. We sought to clarify these relationships by using data from the Western Australian Pregnancy Cohort (Raine) Study. The Raine Study provided comprehensive data from 2,900 pregnancies, resulting in 2,868 live born children. A total of 1,220 participants completed the short form of the Depression Anxiety Stress Scale (DASS-21) at the 20-year cohort follow-up. We used negative binomial regression analyses with log link and with adjustment for known perinatal risk factors to examine the extent to which maternal and paternal age at childbirth predicted continuous DASS-21 index scores. In the final multivariate models, a maternal age of 30-34 years was associated with significant increases in stress DASS-21 scores in female offspring relative to female offspring of 25- to 29-year-old mothers. A maternal age of 35 years and over was associated with increased scores on all DASS-21 scales in female offspring. Our results indicate that older maternal age is associated with depression, anxiety, and stress symptoms in young adult females. Further research into the mechanisms underpinning this relationship is needed. (c) 2016 APA, all rights reserved.

  9. Exploration of mechanisms underlying the strain-rate-dependent mechanical property of single chondrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Trung Dung; Gu, YuanTong, E-mail: yuantong.gu@qut.edu.au [School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Queensland (Australia)

    2014-05-05

    Based on the characterization by Atomic Force Microscopy, we report that the mechanical property of single chondrocytes has dependency on the strain-rates. By comparing the mechanical deformation responses and the Young's moduli of living and fixed chondrocytes at four different strain-rates, we explore the deformation mechanisms underlying this dependency property. We found that the strain-rate-dependent mechanical property of living cells is governed by both of the cellular cytoskeleton and the intracellular fluid when the fixed chondrocytes are mainly governed by their intracellular fluid, which is called the consolidation-dependent deformation behavior. Finally, we report that the porohyperelastic constitutive material model which can capture the consolidation-dependent behavior of both living and fixed chondrocytes is a potential candidature to study living cell biomechanics.

  10. Age modifies the association between serum obestatin, appetite and nutritional status in maintenance hemodialysis patients.

    Science.gov (United States)

    Katkov, Anna; Sinuani, Inna; Azar, Ada; Shapiro, Gregory; Efrati, Shai; Beberashvili, Ilia

    2018-01-23

    Increased age is strongly associated with anorexia and protein-energy wasting (PEW) in maintenance hemodialysis (MHD) population. We hypothesized that the association of obestatin, a recently discovered anorexigenic gut hormone, with appetite and nutritional status differs by age groups. We performed a cross-sectional study on 261MHD patients. Obestatin, acyl-ghrelin, markers of inflammation (CRP, IL-6, TNF-α) and nutrition (self-reported appetite, dietary intake, biochemical nutritional parameters, and body composition) were measured. Obestatin was associated with appetite in multivariate analyses even after controlling for such confounders as lean body mass (LBM), IL-6 and acyl-ghrelin in patients younger than 71 years. For each ng/ml increase in obestatin levels, the odds for diminished appetite was 0.75 (95% CI: 0.59-0.96). However, these associations were not observed in patients 71 years and older. Multivariable logistic regression models (including appetite) also showed increasing odds for PEW (defined by ESPEN consensus-based criteria for the diagnosis of malnutrition) across increasing serum obestatin levels (OR: 1.51, 95% CI: 1.05-2.18) in patients 71 years and older. However, after lean body mass (LBM) was added to this model, the association between obestatin and malnutrition was abolished (OR: 1.26, 95% CI: 0.83-1.91). The association between serum obestatin, appetite and PEW differs depending on age in MHD patients. A positive link with appetite exists in patients younger than 71 years, whereas this relationship disappears by the age of 71. In older MHD patients, obestatin is associated with PEW through mechanisms related to LBM, but not to appetite.

  11. Extrinsic Mechanisms Involved in Age-Related Defective Bone Formation

    DEFF Research Database (Denmark)

    Trinquier, Anne Marie-Pierre Emilie; Kassem, Moustapha

    2011-01-01

    Context: Age-related bone loss is associated with progressive changes in bone remodeling characterized by decreased bone formation relative to bone resorption. Both trabecular and periosteal bone formation decline with age in both sexes, which contributes to bone fragility and increased risk of f...

  12. The Influence of Age and Sex on Genetic Associations with Adult Body Size and Shape

    DEFF Research Database (Denmark)

    Winkler, Thomas W; Justice, Anne E; Graff, Mariaelisa

    2015-01-01

    Genome-wide association studies (GWAS) have identified more than 100 genetic variants contributing to BMI, a measure of body size, or waist-to-hip ratio (adjusted for BMI, WHRadjBMI), a measure of body shape. Body size and shape change as people grow older and these changes differ substantially...... (G x AGE), sex-specific effects (G x SEX) or age-specific effects that differed between men and women (G x AGE x SEX). For BMI, we identified 15 loci (11 previously established for main effects, four novel) that showed significant (FDR... effects on WHRadjBMI. These results may provide further insights into the biology that underlies weight change with age or the sexually dimorphism of body shape....

  13. Deformation Mechanisms of Gum Metals Under Nanoindentation

    Science.gov (United States)

    Sankaran, Rohini Priya

    defect structures to applied loading, we perform ex-situ nanoindentation. Nanoindentation is a convenient method as the plastic deformation is localized and probes a nominally defect free volume of the material. We subsequently characterize the defect structures in these alloys with both conventional TEM and advanced techniques such as HAADF HRSTEM and nanoprobe diffraction. These advanced techniques allow for a more thorough understanding of the observed deformation features. The main findings from this investigation are as follows. As expected we observe that a non-equilibrium phase, o, is present in the leaner beta-stabilized alloy, ST Ref-1. We do not find any direct evidence of secondary phases in STGM, and we find the beta phase in CWGM, along with lath microstructure with subgrain structure consisting of dislocation cell networks. Upon nanoindentation, we find twinning accompanied by beta nucleation on the twin boundary in ST Ref-1 samples. This result is consistent with previous findings and is reasonable considering the alloy is unstable with respect to beta transformation. We find deformation nanotwinning in cold worked gum metals under nanoindentation, which is initially surprising. We argue that when viewed as a nanocrystalline material, such a deformation mechanism is consistent with previous work, and furthermore, a deformation nanotwinned structure does not preclude an ideal shear mechanism from operating in the alloy. Lastly, we observe continuous lattice rotations in STGM under nanoindentation via nanoprobe diffraction. With this technique, for the first time we can demonstrate that the lattice rotations are truly continuous at the nanoscale. We can quantify this lattice rotation, and find that even though the rotation is large, it may be mediated by a reasonable geometrically necessary dislocation density, and note that similar rotations are typically observed in other materials under nanoindentation. HRSTEM and conventional TEM data confirm the

  14. The effect og aging and mechanical loading on the metabolism og articular cartilage

    DEFF Research Database (Denmark)

    Jørgensen, Adam El Mongy; Kjær, Michael; Heinemeier, Katja Maria

    2017-01-01

    Objective. The morphology of articular cartilage (AC) enables painless movement. Aging and mechanical loading are believed to influence development of osteoarthritis (OA), yet the connection remains unclear. Methods. This narrative review describes the current knowledge regarding this area......, with the literature search made on PubMed using appropriate keywords regarding AC, age, and mechanical loading. Results. Following skeletal maturation, chondrocyte numbers decline while increasing senescence occurs. Lower cartilage turnover causes diminished maintenance capacity, which produces accumulation...... collagen network damage and proteoglycan loss, leading to irreversible cartilage destruction because of lack of regenerative capacity. Catabolic pathways involve inflammation and the transcription factor nuclear factor-κB. Thus, age seems to be a predisposing factor for OA, with mechanical overload being...

  15. The Effect of Aging and Mechanical Loading on the Metabolism of Articular Cartilage

    DEFF Research Database (Denmark)

    Jørgensen, Adam El Mongy; Kjaer, Michael; Heinemeier, Katja Maria

    2017-01-01

    Objective. The morphology of articular cartilage (AC) enables painless movement. Aging and mechanical loading are believed to influence development of osteoarthritis (OA), yet the connection remains unclear. Methods. This narrative review describes the current knowledge regarding this area......, with the literature search made on PubMed using appropriate keywords regarding AC, age, and mechanical loading. Results. Following skeletal maturation, chondrocyte numbers decline while increasing senescence occurs. Lower cartilage turnover causes diminished maintenance capacity, which produces accumulation...... collagen network damage and proteoglycan loss, leading to irreversible cartilage destruction because of lack of regenerative capacity. Catabolic pathways involve inflammation and the transcription factor nuclear factor-κB. Thus, age seems to be a predisposing factor for OA, with mechanical overload being...

  16. Serum biomarkers of habitual coffee consumption may provide insight into the mechanism underlying the association between coffee consumption and colorectal cancer.

    Science.gov (United States)

    Guertin, Kristin A; Loftfield, Erikka; Boca, Simina M; Sampson, Joshua N; Moore, Steven C; Xiao, Qian; Huang, Wen-Yi; Xiong, Xiaoqin; Freedman, Neal D; Cross, Amanda J; Sinha, Rashmi

    2015-05-01

    Coffee intake may be inversely associated with colorectal cancer; however, previous studies have been inconsistent. Serum coffee metabolites are integrated exposure measures that may clarify associations with cancer and elucidate underlying mechanisms. Our aims were 2-fold as follows: 1) to identify serum metabolites associated with coffee intake and 2) to examine these metabolites in relation to colorectal cancer. In a nested case-control study of 251 colorectal cancer cases and 247 matched control subjects from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, we conducted untargeted metabolomics analyses of baseline serum by using ultrahigh-performance liquid-phase chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry. Usual coffee intake was self-reported in a food-frequency questionnaire. We used partial Pearson correlations and linear regression to identify serum metabolites associated with coffee intake and conditional logistic regression to evaluate associations between coffee metabolites and colorectal cancer. After Bonferroni correction for multiple comparisons (P = 0.05 ÷ 657 metabolites), 29 serum metabolites were positively correlated with coffee intake (partial correlation coefficients: 0.18-0.61; P 0.40) included trigonelline (N'-methylnicotinate), quinate, and 7 unknown metabolites. Of 29 serum metabolites, 8 metabolites were directly related to caffeine metabolism, and 3 of these metabolites, theophylline (OR for 90th compared with 10th percentiles: 0.44; 95% CI: 0.25, 0.79; P-linear trend = 0.006), caffeine (OR for 90th compared with 10th percentiles: 0.56; 95% CI: 0.35, 0.89; P-linear trend = 0.015), and paraxanthine (OR for 90th compared with 10th percentiles: 0.58; 95% CI: 0.36, 0.94; P-linear trend = 0.027), were inversely associated with colorectal cancer. Serum metabolites can distinguish coffee drinkers from nondrinkers; some caffeine-related metabolites were inversely associated with colorectal

  17. Oxidative Stress Promotes Peroxiredoxin Hyperoxidation and Attenuates Pro-survival Signaling in Aging Chondrocytes*

    Science.gov (United States)

    Collins, John A.; Wood, Scott T.; Nelson, Kimberly J.; Rowe, Meredith A.; Carlson, Cathy S.; Chubinskaya, Susan; Poole, Leslie B.; Furdui, Cristina M.; Loeser, Richard F.

    2016-01-01

    Oxidative stress-mediated post-translational modifications of redox-sensitive proteins are postulated as a key mechanism underlying age-related cellular dysfunction and disease progression. Peroxiredoxins (PRX) are critical intracellular antioxidants that also regulate redox signaling events. Age-related osteoarthritis is a common form of arthritis that has been associated with mitochondrial dysfunction and oxidative stress. The objective of this study was to determine the effect of aging and oxidative stress on chondrocyte intracellular signaling, with a specific focus on oxidation of cytosolic PRX2 and mitochondrial PRX3. Menadione was used as a model to induce cellular oxidative stress. Compared with chondrocytes isolated from young adult humans, chondrocytes from older adults exhibited higher levels of PRX1–3 hyperoxidation basally and under conditions of oxidative stress. Peroxiredoxin hyperoxidation was associated with inhibition of pro-survival Akt signaling and stimulation of pro-death p38 signaling. These changes were prevented in cultured human chondrocytes by adenoviral expression of catalase targeted to the mitochondria (MCAT) and in cartilage explants from MCAT transgenic mice. Peroxiredoxin hyperoxidation was observed in situ in human cartilage sections from older adults and in osteoarthritic cartilage. MCAT transgenic mice exhibited less age-related osteoarthritis. These findings demonstrate that age-related oxidative stress can disrupt normal physiological signaling and contribute to osteoarthritis and suggest peroxiredoxin hyperoxidation as a potential mechanism. PMID:26797130

  18. The effect of age on thymic function

    Directory of Open Access Journals (Sweden)

    Donald B. Palmer

    2013-10-01

    Full Text Available Age-related regression of the thymus is associated with a decline in naïve T cell output. This is thought to contribute to the reduction in T cell diversity seen in older individuals and linked with increased susceptibility to infection, autoimmune disease and cancer. Thymic involution is one of the most dramatic and ubiquitous changes seen in the ageing immune system, but the mechanisms which underlying this process are poorly understood. However, a picture is emerging, implicating the involvement of both extrinsic and intrinsic factors. In this review we assess the role of the thymic microenvironment as a potential target that regulates thymic involution, question whether thymocyte development in the aged thymus is functionally impaired and explore the kinetics of thymic involution.

  19. Age is associated with asthma phenotypes.

    Science.gov (United States)

    Ponte, Eduardo V; Lima, Aline; Almeida, Paula C A; de Jesus, Juliana P V; Lima, Valmar B; Scichilone, Nicola; Souza-Machado, Adelmir; Cruz, Álvaro A

    2017-11-01

    The relationship between age and asthma phenotypes is important as population is ageing, asthma is becoming common in older ages and recently developed treatments for asthma are guided by phenotypes. The aim of this study is to evaluate whether age is associated with specific asthma phenotypes. This is a cross-sectional study. We included subjects with asthma of varied degrees of severity. Subjects underwent spirometry, skin prick test to aeroallergens, answered the Asthma Control Questionnaire and had blood samples collected. We performed binary logistic regression analysis to evaluate whether age is associated with asthma phenotypes. We enrolled 868 subjects. In comparison with subjects ≤ 40 years, older subjects had high odds of irreversible airway obstruction (from 41 to 64 years, OR: 1.83 (95% CI: 1.32-2.54); ≥65 years, OR: 3.45 (2.12-5.60)) and severe asthma phenotypes (from 41 to 64 years, OR: 3.23 (2.26-4.62); ≥65 years, OR: 4.55 (2.39-8.67)). Older subjects had low odds of atopic (from 41 to 64 years, OR: 0.56 (0.39-0.79); ≥65 years, OR: 0.47 (0.27-0.84)) and eosinophilic phenotypes (from 41 to 64 years, OR: 0.63 (0.46-0.84); ≥65 years, OR: 0.39 (0.24-0.64)). Older subjects with asthma have low odds of atopic and eosinophilic phenotypes, whereas they present high odds of irreversible airway obstruction and severe asthma. © 2017 Asian Pacific Society of Respirology.

  20. Reduced telomere length is not associated with early signs of vascular aging in young men born after intrauterine growth restriction: a paradox?

    DEFF Research Database (Denmark)

    Laganovic, M.; Bendix, L.; Rubelj, I.

    2014-01-01

    Objective: The mechanisms that increase cardiovascular risk in individuals born small for gestational age (SGA) are not well understood. Telomere shortening has been suggested to be a predictor of disease onset. Our aim was to determine whether impaired intrauterine growth is associated with earl...... of cardiovascular risk in SGA participants. Follow-up of this cohort will clarify hypothesis and validate telomere dynamics as indicators of future health risks.......Objective: The mechanisms that increase cardiovascular risk in individuals born small for gestational age (SGA) are not well understood. Telomere shortening has been suggested to be a predictor of disease onset. Our aim was to determine whether impaired intrauterine growth is associated with early......IMT, and a trend to increased SBP and heart rate in comparison to the AGA group. Interestingly, SGA men exhibited a 42% longer LTL than the AGA group. LTL was inversely associated with age, BMI, BP and birth parameters. In multiple regression analysis, BMI was the key determinant of SBP and cIMT. Conclusion: Young...

  1. Aging effects on fracture behavior of 63Sn37Pb eutectic solder during tensile tests under the SEM

    International Nuclear Information System (INIS)

    Ding Ying; Wang Chunqing; Li Mingyu; Bang Hansur

    2004-01-01

    This study investigates the influence of aging treatment on fracture behavior of Sn-Pb eutectic solder alloys at different loading rate regime during tensile tests under the scanning electron microscope. In high homologous temperature, the solder exhibit the creep behavior that could be confirmed through the phenomena of grain boundary sliding (GBS) to both as-cast and aged specimens. Owing to the large grain scale after high temperature storage, boundary behavior was limited to some extent for the difficulty in grain rotation and boundary migration. Instead, drastic intragranular deformation occurred. Also, the phase coarsening weakened the combination between lead-rich phase and tin matrix. Consequently, surface fragmentation was detected for the aged specimens. Furthermore, the fracture mechanism changed from intergranular dominated to transgranular dominated with increasing loading rate to both specimens during early stage

  2. Association between dopamine D4 receptor polymorphism and age related changes in brain glucose metabolism.

    Directory of Open Access Journals (Sweden)

    Nora D Volkow

    Full Text Available Aging is associated with reductions in brain glucose metabolism in some cortical and subcortical regions, but the rate of decrease varies significantly between individuals, likely reflecting genetic and environmental factors and their interactions. Here we test the hypothesis that the variant of the dopamine receptor D4 (DRD4 gene (VNTR in exon 3, which has been associated with novelty seeking and sensitivity to environmental stimuli (negative and positive including the beneficial effects of physical activity on longevity, influence the effects of aging on the human brain. We used positron emission tomography (PET and [(18F]fluoro-D-glucose ((18FDG to measure brain glucose metabolism (marker of brain function under baseline conditions (no stimulation in 82 healthy individuals (age range 22-55 years. We determined their DRD4 genotype and found an interaction with age: individuals who did not carry the 7-repeat allele (7R-, n = 53 had a significant (p<0.0001 negative association between age and relative glucose metabolism (normalized to whole brain glucose metabolism in frontal (r = -0.52, temporal (r = -0.51 and striatal regions (r = -0.47, p<0.001; such that older individuals had lower metabolism than younger ones. In contrast, for carriers of the 7R allele (7R+ n = 29, these correlations with age were not significant and they only showed a positive association with cerebellar glucose metabolism (r = +0.55; p = 0.002. Regression slopes of regional brain glucose metabolism with age differed significantly between the 7R+ and 7R- groups in cerebellum, inferior temporal cortex and striatum. These results provide evidence that the DRD4 genotype might modulate the associations between regional brain glucose metabolism and age and that the carriers of the 7R allele appear to be less sensitive to the effects of age on brain glucose metabolism.

  3. Age-associated increase of the active zone protein Bruchpilot within the honeybee mushroom body.

    Directory of Open Access Journals (Sweden)

    Katrin B Gehring

    Full Text Available In honeybees, age-associated structural modifications can be observed in the mushroom bodies. Prominent examples are the synaptic complexes (microglomeruli, MG in the mushroom body calyces, which were shown to alter their size and density with age. It is not known whether the amount of intracellular synaptic proteins in the MG is altered as well. The presynaptic protein Bruchpilot (BRP is localized at active zones and is involved in regulating the probability of neurotransmitter release in the fruit fly, Drosophila melanogaster. Here, we explored the localization of the honeybee BRP (Apis mellifera BRP, AmBRP in the bee brain and examined age-related changes in the AmBRP abundance in the central bee brain and in microglomeruli of the mushroom body calyces. We report predominant AmBRP localization near the membrane of presynaptic boutons within the mushroom body MG. The relative amount of AmBRP was increased in the central brain of two-week old bees whereas the amount of Synapsin, another presynaptic protein involved in the regulation of neurotransmitter release, shows an increase during the first two weeks followed by a decrease. In addition, we demonstrate an age-associated modulation of AmBRP located near the membrane of presynaptic boutons within MG located in mushroom body calyces where sensory input is conveyed to mushroom body intrinsic neurons. We discuss that the observed age-associated AmBRP modulation might be related to maturation processes or to homeostatic mechanisms that might help to maintain synaptic functionality in old animals.

  4. Effect of temperature on cyclic deformation behavior and residual stress relaxation of deep rolled under-aged aluminium alloy AA6110

    International Nuclear Information System (INIS)

    Juijerm, P.; Altenberger, I.

    2007-01-01

    Mechanical surface treatment (deep rolling) was performed at room temperature on the under-aged aluminium wrought alloy AA6110 (Al-Mg-Si-Cu). Afterwards, specimens were cyclically deformed at room and elevated temperatures up to 250 deg. C. The cyclic deformation behavior and s/n-curves of deep rolled under-aged AA6110 were investigated by stress-controlled fatigue tests and compared to the as-polished condition as a reference. The stability of residual stresses as well as diffraction peak broadening under high-loading and/or elevated-temperature conditions was investigated by X-ray diffraction methods before and after fatigue tests. Depth profiles of near-surface residual stresses as well as full width at half maximum (FWHM) values before and after fatigue tests at elevated temperatures are presented. Thermal residual stress relaxation of deep rolled under-aged AA6110 was investigated and analyzed by applying a Zener-Wert-Avrami function. Thermomechanical residual stress relaxation was analyzed through thermal residual stress relaxation and depth profiles of residual stresses before and after fatigue tests. Finally, an effective border line for the deep rolling treatment due to instability of near-surface work hardening was found and established in a stress amplitude-temperature diagram

  5. Crack assessment of pipe under combined thermal and mechanical load

    International Nuclear Information System (INIS)

    Song, Tae Kwang; Kim, Yun Jae

    2009-01-01

    In this paper, J-integral and transient C(t)-integral, which were key parameters in low temperature and high temperature fracture mechanics, under combined thermal and mechanical load were estimated via 3-dimensional finite element analyses. Various type of thermal and mechanical load, material hardening were considered to decrease conservatism in existing solutions. As a results, V-factor and redistribution time for combined thermal and mechanical load were proposed to calculate J-integral and C(t)-integral, respectively.

  6. Volunteering is associated with increased survival in able-bodied participants of the English Longitudinal Study of Ageing.

    Science.gov (United States)

    Rogers, Nina Trivedy; Demakakos, Panayotes; Taylor, Mark Steven; Steptoe, Andrew; Hamer, Mark; Shankar, Aparna

    2016-06-01

    Volunteering has been linked to reduced mortality in older adults, but the mechanisms explaining this effect remain unclear. This study investigated whether volunteering is associated with increased survival in participants of the English Longitudinal Study of Ageing and whether differences in survival are modified by functional disabilities. A multivariate Cox Proportional Hazards model was used to estimate the association of volunteering with survival over a period of 10.9 years in 10 324 participants, while controlling for selected confounders. To investigate effect modification by disability, the analyses were repeated in participants with and without self-reported functional disabilities. Volunteering was associated with a reduced probability of death from all causes in univariate analyses (HR=0.65, CI 0.58 to 0.73, pvolunteers had significantly increased survival compared with able-bodied non-volunteers (HR=0.81, 95% CI 0.69 to 0.95, p=0.009). There was no significant survival advantage among disabled volunteers, compared with disabled non-volunteers (HR=1.06, CI 0.88 to 1.29, p=0.53). Volunteering is associated with reduced mortality in older adults in England, but this effect appears to be limited to volunteers who report no disabilities. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  7. Development and aging of decision-making rationality under risk framework

    Directory of Open Access Journals (Sweden)

    Han-hui LIU

    2014-03-01

    Full Text Available Background Humans often display irrational choice and decision-making due to the frame effect. However, it is unclear whether this irrational choice and decision-making will increase during the aging process. Methods The present research explored development and aging of risky-seeking and rational decision-making with 232 younger adults and 120 older adults. The experiment was a 2 (Age:younger adult and old adult × 2 (Frame: positive and negative × 2 (Relevance: lower level and higher level, with the risky probability as a control variable and the decision-making scores as dependent variables. Results The results revealed that older adults demonstrated much more irrational decision-making (framing effect. In the detail, the risky decision-making score of the older adults in the positive framing was 5.13 ± 2.12, and 6.55 ± 1.05 in the negative framing [F (1, 118 = 21.470, P = 0.000; η2 = 0.156], while the risky decision-making score of the younger adults in the positive framing was 3.18 ± 2.49, and 5.00 ± 2.41 in the negative framing [F (1, 230 = 31.260, P = 0.000; η 2 = 0.121]. Meanwhile, the older adults showed risk seeking for the life-death scenario [F (1, 350 = 4.820, P = 0.029]. Conclusions These results suggested that the hypofunction in orbital and medial prefrontal cortex and amygdale in older adults might be the underlying mechanisms. Furthermore, the susceptibility to expected value (EV of the older adults might decrease although their scores in risky probability understanding were not significantly different from the younger adults. doi: 10.3969/j.issn.1672-6731.2014.03.008

  8. Association between edentulism and angina pectoris in Mexican adults aged 35 years and older: a multivariate analysis of a population-based survey.

    Science.gov (United States)

    Medina-Solís, Carlo Eduardo; Pontigo-Loyola, América Patricia; Pérez-Campos, Eduardo; Hernández-Cruz, Pedro; Ávila-Burgos, Leticia; Kowolik, Michael J; Maupomé, Gerardo

    2014-03-01

    The possible association between oral infection and chronic inflammation and cardiovascular disease risk has been studied intensively. The present study is designed to determine the strength of association between edentulism and angina pectoris in Mexican adults aged 35 years and older. Using the tools and sampling strategies of the World Health Survey of the World Health Organization, cross-sectional data were collected in Mexico in the National Performance Assessment Survey (probabilistic, multistage, and cluster sampling). Dental information was available for 20 of the 32 states of Mexico. Angina and edentulism are self-reported in this study. Statistical analysis was performed using binary logistic regression adjusting for complex samples. A total of 13,966 participants, representing a population of 29,853,607 individuals, were included. Of the complete study population, 3,052,263 (10.2%) were completely toothless, and 673,810 (2.3%) were diagnosed with angina pectoris. After adjusting for smoking, alcohol consumption, diabetes, body mass index, and sex, the effect of edentulism on angina was modified by age (interaction), being more marked in the younger age group (odds ratio [OR] = exp(2.5597) =12.93) than in the older individuals surveyed (OR = exp(2.5597 + (-0.0334)) =12.51). Additionally, low physical activity (OR = 1.51; 95% confidence interval [CI] = 1.03 to 2.22) and higher socioeconomic status (OR = 1.37; 95% CI = 1.00 to 1.90) were more likely to be associated with angina pectoris. Overall, the results of this study, conducted in a representative sample of Mexican adults, suggest that an association exists between edentulism and angina pectoris. Additional studies are necessary to elucidate the underlying mechanism for this association.

  9. Mechanisms and pharmacogenetic signals underlying thiazide diuretics blood pressure response.

    Science.gov (United States)

    Shahin, Mohamed H; Johnson, Julie A

    2016-04-01

    Thiazide (TZD) diuretics are among the most commonly prescribed antihypertensives globally; however their chronic blood pressure (BP) lowering mechanism remains unclear. Herein we discuss the current evidence regarding specific mechanisms regulating the antihypertensive effects of TZDs, suggesting that TZDs act via multiple complex and interacting mechanisms, including natriuresis with short term use and direct vasodilatory effects chronically. Additionally, we review pharmacogenomics signals that have been associated with TZDs BP-response in several cohorts (i.e. NEDD4L, PRKCA, EDNRA-GNAS, and YEATS4) and discuss how these genes might be related to TZD BP-response mechanism. Understanding the association between these genes and TZD BP mechanism might facilitate the development of new drugs and therapeutic approaches based on a deeper understanding of the determinants of BP-response. Copyright © 2016. Published by Elsevier Ltd.

  10. Psychological flexibility and catastrophizing as associated change mechanisms during online Acceptance & Commitment Therapy for chronic pain

    NARCIS (Netherlands)

    Trompetter, H.R.; Bohlmeijer, Ernst Thomas; Fox, Gerardus J.A.; Schreurs, Karlein Maria Gertrudis

    2015-01-01

    The underlying mechanisms of the effectiveness of cognitive behavioural interventions for chronic pain need further clarification. The role of, and associations between, pain-related psychological flexibility (PF) and pain catastrophizing (PC) were examined during a randomized controlled trial on

  11. Neurodevelopmental Disorders and Environmental Toxicants: Epigenetics as an Underlying Mechanism

    Science.gov (United States)

    2017-01-01

    The increasing prevalence of neurodevelopmental disorders, especially autism spectrum disorders (ASD) and attention deficit hyperactivity disorder (ADHD), calls for more research into the identification of etiologic and risk factors. The Developmental Origin of Health and Disease (DOHaD) hypothesizes that the environment during fetal and childhood development affects the risk for many chronic diseases in later stages of life, including neurodevelopmental disorders. Epigenetics, a term describing mechanisms that cause changes in the chromosome state without affecting DNA sequences, is suggested to be the underlying mechanism, according to the DOHaD hypothesis. Moreover, many neurodevelopmental disorders are also related to epigenetic abnormalities. Experimental and epidemiological studies suggest that exposure to prenatal environmental toxicants is associated with neurodevelopmental disorders. In addition, there is also evidence that environmental toxicants can result in epigenetic alterations, notably DNA methylation. In this review, we first focus on the relationship between neurodevelopmental disorders and environmental toxicants, in particular maternal smoking, plastic-derived chemicals (bisphenol A and phthalates), persistent organic pollutants, and heavy metals. We then review studies showing the epigenetic effects of those environmental factors in humans that may affect normal neurodevelopment. PMID:28567415

  12. Neurodevelopmental Disorders and Environmental Toxicants: Epigenetics as an Underlying Mechanism

    Directory of Open Access Journals (Sweden)

    Nguyen Quoc Vuong Tran

    2017-01-01

    Full Text Available The increasing prevalence of neurodevelopmental disorders, especially autism spectrum disorders (ASD and attention deficit hyperactivity disorder (ADHD, calls for more research into the identification of etiologic and risk factors. The Developmental Origin of Health and Disease (DOHaD hypothesizes that the environment during fetal and childhood development affects the risk for many chronic diseases in later stages of life, including neurodevelopmental disorders. Epigenetics, a term describing mechanisms that cause changes in the chromosome state without affecting DNA sequences, is suggested to be the underlying mechanism, according to the DOHaD hypothesis. Moreover, many neurodevelopmental disorders are also related to epigenetic abnormalities. Experimental and epidemiological studies suggest that exposure to prenatal environmental toxicants is associated with neurodevelopmental disorders. In addition, there is also evidence that environmental toxicants can result in epigenetic alterations, notably DNA methylation. In this review, we first focus on the relationship between neurodevelopmental disorders and environmental toxicants, in particular maternal smoking, plastic-derived chemicals (bisphenol A and phthalates, persistent organic pollutants, and heavy metals. We then review studies showing the epigenetic effects of those environmental factors in humans that may affect normal neurodevelopment.

  13. Language Learning Enhanced by Massive Multiple Online Role-Playing Games (MMORPGs) and the Underlying Behavioral and Neural Mechanisms

    OpenAIRE

    Zhang, Yongjun; Song, Hongwen; Liu, Xiaoming; Tang, Dinghong; Chen, Yue-e; Zhang, Xiaochu

    2017-01-01

    Massive Multiple Online Role-Playing Games (MMORPGs) have increased in popularity among children, juveniles, and adults since MMORPGs’ appearance in this digital age. MMORPGs can be applied to enhancing language learning, which is drawing researchers’ attention from different fields and many studies have validated MMORPGs’ positive effect on language learning. However, there are few studies on the underlying behavioral or neural mechanism of such effect. This paper reviews the educational app...

  14. Age-ordered shirt numbering reduces the selection bias associated with the relative age effect.

    Science.gov (United States)

    Mann, David L; van Ginneken, Pleun J M A

    2017-04-01

    When placed into age groups for junior sporting competition, the relative differences in age between children leads to a bias in who is evaluated as being talented. While the impact of this relative age effect (RAE) is clear, until now there has been no evidence to show how to reduce it. The aim of this study was to determine whether the selection bias associated with the RAE could be reduced. Talent scouts from an elite football club watched junior games and ranked players on the basis of their potential. Scouts were allocated to one of three groups provided with contrasting information about the age of the players: (1) no age information, (2) players' birthdates or (3) knowledge that the numbers on the playing shirts corresponded to the relative age of the players. Results revealed a significant selection bias for the scouts in the no-age information group, and that bias remained when scouts knew the players' dates-of-birth. Strikingly though, the selection bias was eliminated when scouts watched the games knowing the shirt numbers corresponded to the relative ages of the players. The selection bias associated with the RAE can be reduced if information about age is presented appropriately.

  15. Chest radiological patterns predict the duration of mechanical ventilation in children with RSV infection

    International Nuclear Information System (INIS)

    Prodhan, Parthak; Westra, Sjirk J.; Lin, James; Karni-Sharoor, Sarit; Regan, Susan; Noviski, Natan

    2009-01-01

    RSV-infected children demonstrate various radiographic features, some of which are associated with worse clinical outcomes. To investigate whether specific chest radiological patterns in RSV-infected children with acute respiratory failure (ARF) in the peri-intubation period are associated with prolonged duration of mechanical ventilation. We included RSV-infected children 8 days, a backward stepwise regression arrived at a model that included age and right and left lung atelectasis. Using day 2 chest radiograph results, the best model included age and left lung atelectasis. A model combining the two days' findings yielded an area under the ROC curve of 0.92 with a satisfactory fit (P = 0.95). Chest radiological patterns around the time of intubation can identify children with RSV-associated ARF who would require prolonged mechanical ventilation. (orig.)

  16. Time Perspective and Age: A Review of Age Associated Differences.

    Science.gov (United States)

    Laureiro-Martinez, Daniella; Trujillo, Carlos A; Unda, Juliana

    2017-01-01

    We investigate the relationship between age and the five dimensions of time perspective measured by the Zimbardo Time Perspective Inventory (ZTPI) (past negative, past positive, present hedonistic, present fatalistic, and future). Time perspective is related to well-being, decision-making, level of development, and many other psychological issues. Hence, the existence of a systematic relationship between time perspective and age should be considered in all studies for which time is a relevant variable. However, no specific research about this has been conducted. We collected 407 papers that referenced the ZTPI between 2001 and 2015. From those, 72 studies met our inclusion criteria. They included 29,815 participants from 19 countries whose age spans most phases of adulthood (from 13.5 to 75.5 years, mean 28.7). We analyzed these studies adapting meta-analytical techniques. We found that present hedonistic and past negative dimensions are negatively related to aging with partial eta squared effect sizes of roughly 0.15. Our results have implications for the design of studies related to time as our findings highlight the importance of taking into account the differences associated with age.

  17. A Western Diet Pattern Is Associated with Higher Concentrations of Blood and Bone Lead among Middle-Aged and Elderly Men.

    Science.gov (United States)

    Wang, Xin; Ding, Ning; Tucker, Katherine L; Weisskopf, Marc G; Sparrow, David; Hu, Howard; Park, Sung Kyun

    2017-07-01

    a greater lead body burden among the middle-aged-to-elderly men. More studies are needed to examine the underlying mechanisms by which dietary patterns are associated with lead concentrations. © 2017 American Society for Nutrition.

  18. Study of the aging processes in polyurethane adhesives using thermal treatment and differential calorimetric, dielectric, and mechanical techniques ; 1, identifying the aging processes ; 2, quantifying the aging effect

    CERN Document Server

    Althouse, L P

    1979-01-01

    Study of the aging processes in polyurethane adhesives using thermal treatment and differential calorimetric, dielectric, and mechanical techniques ; 1, identifying the aging processes ; 2, quantifying the aging effect

  19. Aging and Cortical Mechanisms of Speech Perception in Noise

    Science.gov (United States)

    Wong, Patrick C. M.; Jin, James Xumin; Gunasekera, Geshri M.; Abel, Rebekah; Lee, Edward R.; Dhar, Sumitrajit

    2009-01-01

    Spoken language processing in noisy environments, a hallmark of the human brain, is subject to age-related decline, even when peripheral hearing might be intact. The present study examines the cortical cerebral hemodynamics (measured by fMRI) associated with such processing in the aging brain. Younger and older subjects identified single words in…

  20. Association between SERPING1 rs2511989 polymorphism and age-related macular degeneration: Meta-analysis

    Directory of Open Access Journals (Sweden)

    Yi Dong

    2015-04-01

    Full Text Available AIM: To investigate the association between SERPING1 rs2511989 (G>A polymorphism and age-related macular degeneration (AMD. METHODS: A number of electronic databases (up to July 15, 2014 were searched independently by two investigators. A Meta-analysis was performed on the association between SERPING1 rs2511989 polymorphism and AMD. Pooled odds ratios (ORs with 95% confidence intervals (CIs were estimated. RESULTS: Eight studies with 16 cohorts consisting of 9163 cases and 6813 controls were included in this Meta-analysis. There was no significant association between rs2511989 polymorphism and AMD under all genetic models in overall estimates (A vs G: OR= 0.938, 95%CI =0.858-1.025; AA vs GG:OR =0.871, 95%CI =0.719-1.056; AG vs GG: OR =0.944, 95%CI =0.845-1.054; AA+AG vs GG: OR =0.927, 95% CI =0.823-1.044; AA vs AG+GG: OR =0.890, 95%CI =0.780-1.034. Cumulative Meta-analyses also showed a trend of no association between rs2511989 polymorphism and AMD as information accumulated by year. Subgroup analysis and Meta-regression analysis indicated that age-matching status was the main source of heterogeneity. Sensitivity analysis found the results in overall comparisons and subgroup comparisons of white subjects under the allele model were found to have significantly statistical differences after studies deviating from Hardy-Weinberg equilibrium (HWE were excluded (overall: OR=0.918, 95%CI = 0.844-0.999, P =0.049; whites: OR =0.901, 95%CI = 0.817-0.994, P =0.038. However, the results were not sufficiently robust for further sensitivity analysis and statistical differences disappeared on applying Bonferroni correction (with a significance level set at 0.05/25. CONCLUSION: This Meta-analysis indicates that SERPING1 rs2511989 polymorphism and AMD tend to have no association with each other. Age matching status is a big confounding factor, and more studies with subtle designs are warranted in future.

  1. Mechanism of crack initiation and crack growth under thermal and mechanical fatigue loading

    Energy Technology Data Exchange (ETDEWEB)

    Utz, S.; Soppa, E.; Silcher, H.; Kohler, C. [Stuttgart Univ. (Germany). Materials Testing Inst.

    2013-07-01

    The present contribution is focused on the experimental investigations and numerical simulations of the deformation behaviour and crack development in the austenitic stainless steel X6CrNiNb18-10 under thermal and mechanical cyclic loading in HCF and LCF regimes. The main objective of this research is the understanding of the basic mechanisms of fatigue damage and the development of simulation methods, which can be applied further in safety evaluations of nuclear power plant components. In this context the modelling of crack initiation and crack growth inside the material structure induced by varying thermal or mechanical loads are of particular interest. The mechanisms of crack initiation depend among other things on the type of loading, microstructure, material properties and temperature. The Nb-stabilized austenitic stainless steel in the solution-annealed condition was chosen for the investigations. Experiments with two kinds of cyclic loading - pure thermal and pure mechanical - were carried out and simulated. The fatigue behaviour of the steel X6CrNiNb18-10 under thermal loading was studied within the framework of the joint research project [4]. Interrupted thermal cyclic tests in the temperature range of 150 C to 300 C combined with non-destructive residual stress measurements (XRD) and various microscopic investigations, e.g. in SEM (Scanning Electron Microscope), were used to study the effects of thermal cyclic loading on the material. This thermal cyclic loading leads to thermal induced stresses and strains. As a result intrusions and extrusions appear inside the grains (at the surface), at which microcracks arise and evolve to a dominant crack. Finally, these microcracks cause a continuous and significant decrease of residual stresses. The fatigue behaviour of the steel X6CrNiNb18-10 under mechanical loading at room temperature was studied within the framework of the research project [5], [8]. With a combination of interrupted LCF tests and EBSD

  2. Mechanism of crack initiation and crack growth under thermal and mechanical fatigue loading

    International Nuclear Information System (INIS)

    Utz, S.; Soppa, E.; Silcher, H.; Kohler, C.

    2013-01-01

    The present contribution is focused on the experimental investigations and numerical simulations of the deformation behaviour and crack development in the austenitic stainless steel X6CrNiNb18-10 under thermal and mechanical cyclic loading in HCF and LCF regimes. The main objective of this research is the understanding of the basic mechanisms of fatigue damage and the development of simulation methods, which can be applied further in safety evaluations of nuclear power plant components. In this context the modelling of crack initiation and crack growth inside the material structure induced by varying thermal or mechanical loads are of particular interest. The mechanisms of crack initiation depend among other things on the type of loading, microstructure, material properties and temperature. The Nb-stabilized austenitic stainless steel in the solution-annealed condition was chosen for the investigations. Experiments with two kinds of cyclic loading - pure thermal and pure mechanical - were carried out and simulated. The fatigue behaviour of the steel X6CrNiNb18-10 under thermal loading was studied within the framework of the joint research project [4]. Interrupted thermal cyclic tests in the temperature range of 150 C to 300 C combined with non-destructive residual stress measurements (XRD) and various microscopic investigations, e.g. in SEM (Scanning Electron Microscope), were used to study the effects of thermal cyclic loading on the material. This thermal cyclic loading leads to thermal induced stresses and strains. As a result intrusions and extrusions appear inside the grains (at the surface), at which microcracks arise and evolve to a dominant crack. Finally, these microcracks cause a continuous and significant decrease of residual stresses. The fatigue behaviour of the steel X6CrNiNb18-10 under mechanical loading at room temperature was studied within the framework of the research project [5], [8]. With a combination of interrupted LCF tests and EBSD

  3. Parent-of-origin specific allelic associations among 106 genomic loci for age at menarche

    OpenAIRE

    Perry, John RB; Day, Felix; Elks, Cathy E; Sulem, Patrick; Thompson, Deborah J; Ferreira, Teresa; He, Chunyan; Chasman, Daniel I; Esko, T?nu; Thorleifsson, Gudmar; Albrecht, Eva; Ang, Wei Q; Corre, Tanguy; Cousminer, Diana L; Feenstra, Bjarke

    2014-01-01

    textabstractAge at menarche is a marker of timing of puberty in females. It varies widely between individuals, is a heritable trait and is associated with risks for obesity, type 2 diabetes, cardiovascular disease, breast cancer and all-cause mortality. Studies of rare human disorders of puberty and animal models point to a complex hypothalamic-pituitary-hormonal regulation, but the mechanisms that determine pubertal timing and underlie its links to disease risk remain unclear. Here, using ge...

  4. Optimal Dynamic Advertising Strategy Under Age-Specific Market Segmentation

    Science.gov (United States)

    Krastev, Vladimir

    2011-12-01

    We consider the model proposed by Faggian and Grosset for determining the advertising efforts and goodwill in the long run of a company under age segmentation of consumers. Reducing this model to optimal control sub problems we find the optimal advertising strategy and goodwill.

  5. Physiological Aging: Links Among Adipose Tissue Dysfunction, Diabetes, and Frailty.

    Science.gov (United States)

    Stout, Michael B; Justice, Jamie N; Nicklas, Barbara J; Kirkland, James L

    2017-01-01

    Advancing age is associated with progressive declines in physiological function that lead to overt chronic disease, frailty, and eventual mortality. Importantly, age-related physiological changes occur in cellularity, insulin-responsiveness, secretory profiles, and inflammatory status of adipose tissue, leading to adipose tissue dysfunction. Although the mechanisms underlying adipose tissue dysfunction are multifactorial, the consequences result in secretion of proinflammatory cytokines and chemokines, immune cell infiltration, an accumulation of senescent cells, and an increase in senescence-associated secretory phenotype (SASP). These processes synergistically promote chronic sterile inflammation, insulin resistance, and lipid redistribution away from subcutaneous adipose tissue. Without intervention, these effects contribute to age-related systemic metabolic dysfunction, physical limitations, and frailty. Thus adipose tissue dysfunction may be a fundamental contributor to the elevated risk of chronic disease, disability, and adverse health outcomes with advancing age. ©2017 Int. Union Physiol. Sci./Am. Physiol. Soc.

  6. [Aging and homeostasis. Management of disorders in bone and calcium metabolism associated with ageing.

    Science.gov (United States)

    Takeuchi, Yasuhiro

    Disorders in bone and calcium metabolism associated with aging are based on secondary hyperparathyroidism due to impaired intestinal calcium absorption caused by insufficient vitamin D actions and augmented bone resorption due to sex hormone deficiency. Both of them are involved in the development of osteoporosis that increases risk of fractures. Therefore, the most important thing for management of disorders in bone and calcium metabolism associated with aging is to prevent fractures with appropriate drugs for osteoporosis.

  7. Effect of cold work and aging on mechanical properties of a copper ...

    Indian Academy of Sciences (India)

    Unknown

    Influence of cold working and aging on the mechanical properties of a ... toughness and ductility in various stages of cold work and aging may include high stress concentration at high ... copper is added to HSLA steels to cause precipitation.

  8. CREB Overexpression Ameliorates Age-related Behavioral and Biophysical Deficits

    Science.gov (United States)

    Yu, Xiao-Wen

    Age-related cognitive deficits are observed in both humans and animals. Yet, the molecular mechanisms underlying these deficits are not yet fully elucidated. In aged animals, a decrease in intrinsic excitability of pyramidal neurons from the CA1 sub-region of hippocampus is believed to contribute to age-related cognitive impairments, but the molecular mechanism(s) that modulate both these factors has yet to be identified. Increasing activity of the transcription factor cAMP response element-binding protein (CREB) in young adult rodents has been shown to facilitate cognition, and increase intrinsic excitability of their neurons. However, how CREB changes with age, and how that impacts cognition in aged animals, is not clear. Therefore, we first systematically characterized age- and training-related changes in CREB levels in dorsal hippocampus. At a remote time point after undergoing behavioral training, levels of total CREB and activated CREB (phosphorylated at S133, pCREB) were measured in both young and aged rats. We found that pCREB, but not total CREB was significantly reduced in dorsal CA1 of aged rats. Importantly, levels of pCREB were found to be positively correlated with short-term spatial memory in both young and aged rats i.e. higher pCREB in dorsal CA1 was associated with better spatial memory. These findings indicate that an age-related deficit in CREB activity may contribute to the development of age-related cognitive deficits. However, it was still unclear if increasing CREB activity would be sufficient to ameliorate age-related cognitive, and biophysical deficits. To address this question, we virally overexpressed CREB in CA1, where we found the age-related deficit. Young and aged rats received control or CREB virus, and underwent water maze training. While control aged animals exhibited deficits in long-term spatial memory, aged animals with CREB overexpression performed at levels comparable to young animals. Concurrently, aged neurons

  9. Single-cell network profiling of peripheral blood mononuclear cells from healthy donors reveals age- and race-associated differences in immune signaling pathway activation.

    Science.gov (United States)

    Longo, Diane M; Louie, Brent; Putta, Santosh; Evensen, Erik; Ptacek, Jason; Cordeiro, James; Wang, Ena; Pos, Zoltan; Hawtin, Rachael E; Marincola, Francesco M; Cesano, Alessandra

    2012-02-15

    A greater understanding of the function of the human immune system at the single-cell level in healthy individuals is critical for discerning aberrant cellular behavior that occurs in settings such as autoimmunity, immunosenescence, and cancer. To achieve this goal, a systems-level approach capable of capturing the response of the interdependent immune cell types to external stimuli is required. In this study, an extensive characterization of signaling responses in multiple immune cell subpopulations within PBMCs from a cohort of 60 healthy donors was performed using single-cell network profiling (SCNP). SCNP is a multiparametric flow cytometry-based approach that enables the simultaneous measurement of basal and evoked signaling in multiple cell subsets within heterogeneous populations. In addition to establishing the interindividual degree of variation within a broad panel of immune signaling responses, the possible association of any observed variation with demographic variables including age and race was investigated. Using half of the donors as a training set, multiple age- and race-associated variations in signaling responses in discrete cell subsets were identified, and several were subsequently confirmed in the remaining samples (test set). Such associations may provide insight into age-related immune alterations associated with high infection rates and diminished protection following vaccination and into the basis for ethnic differences in autoimmune disease incidence and treatment response. SCNP allowed for the generation of a functional map of healthy immune cell signaling responses that can provide clinically relevant information regarding both the mechanisms underlying immune pathological conditions and the selection and effect of therapeutics.

  10. Light-sensitive brain pathways and aging.

    Science.gov (United States)

    Daneault, V; Dumont, M; Massé, É; Vandewalle, G; Carrier, J

    2016-03-15

    Notwithstanding its effects on the classical visual system allowing image formation, light acts upon several non-image-forming (NIF) functions including body temperature, hormonal secretions, sleep-wake cycle, alertness, and cognitive performance. Studies have shown that NIF functions are maximally sensitive to blue wavelengths (460-480 nm), in comparison to longer light wavelengths. Higher blue light sensitivity has been reported for melatonin suppression, pupillary constriction, vigilance, and performance improvement but also for modulation of cognitive brain functions. Studies investigating acute stimulating effects of light on brain activity during the execution of cognitive tasks have suggested that brain activations progress from subcortical regions involved in alertness, such as the thalamus, the hypothalamus, and the brainstem, before reaching cortical regions associated with the ongoing task. In the course of aging, lower blue light sensitivity of some NIF functions has been reported. Here, we first describe neural pathways underlying effects of light on NIF functions and we discuss eye and cerebral mechanisms associated with aging which may affect NIF light sensitivity. Thereafter, we report results of investigations on pupillary constriction and cognitive brain sensitivity to light in the course of aging. Whereas the impact of light on cognitive brain responses appears to decrease substantially, pupillary constriction seems to remain more intact over the lifespan. Altogether, these results demonstrate that aging research should take into account the diversity of the pathways underlying the effects of light on specific NIF functions which may explain their differences in light sensitivity.

  11. Physical Activity Is Positively Associated with Episodic Memory in Aging.

    Science.gov (United States)

    Hayes, Scott M; Alosco, Michael L; Hayes, Jasmeet P; Cadden, Margaret; Peterson, Kristina M; Allsup, Kelly; Forman, Daniel E; Sperling, Reisa A; Verfaellie, Mieke

    2015-11-01

    Aging is associated with performance reductions in executive function and episodic memory, although there is substantial individual variability in cognition among older adults. One factor that may be positively associated with cognition in aging is physical activity. To date, few studies have objectively assessed physical activity in young and older adults, and examined whether physical activity is differentially associated with cognition in aging. Young (n=29, age 18-31 years) and older adults (n=31, ages 55-82 years) completed standardized neuropsychological testing to assess executive function and episodic memory capacities. An experimental face-name relational memory task was administered to augment assessment of episodic memory. Physical activity (total step count and step rate) was objectively assessed using an accelerometer, and hierarchical regressions were used to evaluate relationships between cognition and physical activity. Older adults performed more poorly on tasks of executive function and episodic memory. Physical activity was positively associated with a composite measure of visual episodic memory and face-name memory accuracy in older adults. Physical activity associations with cognition were independent of sedentary behavior, which was negatively correlated with memory performance. Physical activity was not associated with cognitive performance in younger adults. Physical activity is positively associated with episodic memory performance in aging. The relationship appears to be strongest for face-name relational memory and visual episodic memory, likely attributable to the fact that these tasks make strong demands on the hippocampus. The results suggest that physical activity relates to cognition in older, but not younger adults.

  12. Associations between temporary employment and occupational injury: what are the mechanisms?

    Science.gov (United States)

    Benavides, F G; Benach, J; Muntaner, C; Delclos, G L; Catot, N; Amable, M

    2006-06-01

    To determine whether observed higher risks of occupational injury among temporary workers are due to exposure to hazardous working conditions and/or to lack of job experience level. Data systematically recorded for 2000 and 2001 by the Spanish Ministry of Labour and Social Affairs on fatal and non-fatal traumatic occupational injuries were examined by type of employment and type of accident, while adjusting for gender, age, occupation, and length of employment in the company. In the study period there were 1500 fatal and 1 806 532 non-fatal traumatic occupational injuries that occurred at the workplace. Incidence rates and rate ratios (RR) were estimated using Poisson regression models. Temporary workers showed a rate ratio of 2.94 for non-fatal occupational injuries (95% CI 2.40 to 3.61) and 2.54 for fatal occupational injuries (95% CI 1.88 to 3.42). When these associations were adjusted by gender, age, occupation, and especially length of employment, they loose statistic significance: 1.05 (95% CI 0.97 to 1.12) for non-fatal and 1.07 (95% CI 0.91 to 1.26) for fatal. Lower job experience and knowledge of workplace hazards, measured by length of employment, is a possible mechanism to explain the consistent association between temporary workers and occupational injury. The role of working conditions associated with temporary jobs should be assessed more specifically.

  13. A robust TDT-type association test under informative parental missingness.

    Science.gov (United States)

    Chen, J H; Cheng, K F

    2011-02-10

    Many family-based association tests rely on the random transmission of alleles from parents to offspring. Among them, the transmission/disequilibrium test (TDT) may be considered to be the most popular statistical test. The TDT statistic and its variations were proposed to evaluate nonrandom transmission of alleles from parents to the diseased children. However, in family studies, parental genotypes may be missing due to parental death, loss, divorce, or other reasons. Under some missingness conditions, nonrandom transmission of alleles may still occur even when the gene and disease are not associated. As a consequence, the usual TDT-type tests would produce excessive false positive conclusions in association studies. In this paper, we propose a novel TDT-type association test which is not only simple in computation but also robust to the joint effect of population stratification and informative parental missingness. Our test is model-free and allows for different mechanisms of parental missingness across subpopulations. We use a simulation study to compare the performance of the new test with TDT and point out the advantage of the new method. Copyright © 2010 John Wiley & Sons, Ltd.

  14. Late-Age Properties of Concrete with Different Binders Cured under 45°C at Early Ages

    Directory of Open Access Journals (Sweden)

    Hu Jin

    2017-01-01

    Full Text Available It is commonly accepted that high curing temperature (near 60°C or above results in reduced mechanical properties and durability of concrete compared to normal curing temperature. The internal temperature of concrete structures at early ages is not so high as 60°C in many circumstances. In this paper, concretes were cured at 45°C at early ages and their late-age properties were studied. The concrete cured at 20°C was employed as the reference sample. Four different concretes were used: plain cement concrete, concrete containing fly ash, concrete containing ground granulate blast furnace slag (GGBS, and concrete containing silica fume. The results show that, for each concrete, high-temperature curing after precuring does not have any adverse effect on the nonevaporable water content, compressive strength, permeability to chloride ions, and the connected porosity of concrete at late ages compared with standard curing. Additionally, high-temperature curing improves the late-age properties of concrete containing fly ash and GGBS.

  15. Senescence-associated intrinsic mechanisms of osteoblast dysfunctions

    DEFF Research Database (Denmark)

    Kassem, Moustapha; Trinquier, Anne Marie-Pierre Emilie

    2011-01-01

    Human aging is associated with bone loss leading to bone fragility and increased risk of fractures. The cellular and molecular causes of age-related bone loss are current intensive topic of investigation with the aim of identifying new approaches to abolish its negative effects on the skeleton. A...

  16. Mechanical characterization of Ti-12Mo-13Nb alloy for biomedical application hot swaged and aged

    Energy Technology Data Exchange (ETDEWEB)

    Gabriel, Sinara Borborema; Rezende, Monica Castro; Almeida, Luiz Henrique de, E-mail: sinara@metalmat.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Departamento de Engenharia Metalurgica e de Materiais; Dille, Jean [Universite Libre de Bruxelles, Brussels (Belgium); Mei, Paulo [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Departamento de Engenharia Mecanica; Baldan, Renato; Nunes, Carlos Angelo [Universidade de Sao Paulo (USP), Lorena, SP (Brazil). Departamento de Engenharia de Materiais

    2015-07-01

    Beta titanium alloys were developed for biomedical applications due to the combination of its mechanical properties including low elasticity modulus, high strength, fatigue resistance, good ductility and with excellent corrosion resistance. With this perspective a metastable beta titanium alloy Ti-12Mo-13Nb was developed with the replacement of both vanadium and aluminum from the traditional alloy Ti-6Al-4V. This paper presents the microstructure, mechanical properties of the Ti-12Mo-13Nb hot swaged and aged at 500 deg C for 24 h under high vacuum and then water quenched. The alloy structure was characterized by X-ray diffraction and transmission electron microscopy. Tensile tests were carried out at room temperature. The results show a microstructure consisting of a fine dispersed α phase in a β matrix and good mechanical properties including low elastic modulus. The results indicate that Ti-12Mo-13Nb alloy can be a promising alternative for biomedical application. (author)

  17. Fracture mechanics of hydroxyapatite single crystals under geometric confinement.

    Science.gov (United States)

    Libonati, Flavia; Nair, Arun K; Vergani, Laura; Buehler, Markus J

    2013-04-01

    Geometric confinement to the nanoscale, a concept that refers to the characteristic dimensions of structural features of materials at this length scale, has been shown to control the mechanical behavior of many biological materials or their building blocks, and such effects have also been suggested to play a crucial role in enhancing the strength and toughness of bone. Here we study the effect of geometric confinement on the fracture mechanism of hydroxyapatite (HAP) crystals that form the mineralized phase in bone. We report a series of molecular simulations of HAP crystals with an edge crack on the (001) plane under tensile loading, and we systematically vary the sample height whilst keeping the sample and the crack length constant. We find that by decreasing the sample height the stress concentration at the tip of the crack disappears for samples with a height smaller than 4.15nm, below which the material shows a different failure mode characterized by a more ductile mechanism with much larger failure strains, and the strength approaching that of a flaw-less crystal. This study directly confirms an earlier suggestion of a flaw-tolerant state that appears under geometric confinement and may explain the mechanical stability of the reinforcing HAP platelets in bone. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Upregulation of Ih expressed in IB4-negative Aδ nociceptive DRG neurons contributes to mechanical hypersensitivity associated with cervical radiculopathic pain

    OpenAIRE

    Da-Lu Liu; Na Lu; Wen-Juan Han; Rong-Gui Chen; Rui Cong; Rou-Gang Xie; Yu-Fei Zhang; Wei-Wei Kong; San-Jue Hu; Ceng Luo

    2015-01-01

    Cervical radiculopathy represents aberrant mechanical hypersensitivity. Primary sensory neuron?s ability to sense mechanical force forms mechanotransduction. However, whether this property undergoes activity-dependent plastic changes and underlies mechanical hypersensitivity associated with cervical radiculopathic pain (CRP) is not clear. Here we show a new CRP model producing stable mechanical compression of dorsal root ganglion (DRG), which induces dramatic behavioral mechanical hypersensit...

  19. Believing versus interacting: Behavioural and neural mechanisms underlying interpersonal coordination

    DEFF Research Database (Denmark)

    Konvalinka, Ivana; Bauer, Markus; Kilner, James

    When two people engage in a bidirectional interaction with each other, they use both bottom-up sensorimotor mechanisms such as monitoring and adapting to the behaviour of the other, as well as top-down cognitive processes, modulating their beliefs and allowing them to make decisions. Most research...... in joint action has investigated only one of these mechanisms at a time – low-level processes underlying joint coordination, or high-level cognitive mechanisms that give insight into how people think about another. In real interactions, interplay between these two mechanisms modulates how we interact...

  20. Inflammatory Mechanisms Associated with Skeletal Muscle Sequelae after Stroke: Role of Physical Exercise

    Science.gov (United States)

    Coelho Junior, Hélio José; Gambassi, Bruno Bavaresco; Diniz, Tiego Aparecido; Fernandes, Isabela Maia da Cruz; Caperuto, Érico Chagas; Uchida, Marco Carlos; Lira, Fabio Santos

    2016-01-01

    Inflammatory markers are increased systematically and locally (e.g., skeletal muscle) in stroke patients. Besides being associated with cardiovascular risk factors, proinflammatory cytokines seem to play a key role in muscle atrophy by regulating the pathways involved in this condition. As such, they may cause severe decrease in muscle strength and power, as well as impairment in cardiorespiratory fitness. On the other hand, physical exercise (PE) has been widely suggested as a powerful tool for treating stroke patients, since PE is able to regenerate, even if partially, physical and cognitive functions. However, the mechanisms underlying the beneficial effects of physical exercise in poststroke patients remain poorly understood. Thus, in this study we analyze the candidate mechanisms associated with muscle atrophy in stroke patients, as well as the modulatory effect of inflammation in this condition. Later, we suggest the two strongest anti-inflammatory candidate mechanisms, myokines and the cholinergic anti-inflammatory pathway, which may be activated by physical exercise and may contribute to a decrease in proinflammatory markers of poststroke patients. PMID:27647951

  1. Thalamic structures and associated cognitive functions: Relations with age and aging

    Science.gov (United States)

    Fama, Rosemary; Sullivan, Edith V.

    2015-01-01

    The thalamus, with its cortical, subcortical, and cerebellar connections, is a critical node in networks supporting cognitive functions known to decline in normal aging, including component processes of memory and executive functions of attention and information processing. The macrostructure, microstructure, and neural connectivity of the thalamus changes across the adult lifespan. Structural and functional magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) have demonstrated, regional thalamic volume shrinkage and microstructural degradation, with anterior regions generally more compromised than posterior regions. The integrity of selective thalamic nuclei and projections decline with advancing age, particularly those in thalamofrontal, thalamoparietal, and thalamolimbic networks. This review presents studies that assess the relations between age and aging and the structure, function, and connectivity of the thalamus and associated neural networks and focuses on their relations with processes of attention, speed of information processing, and working and episodic memory. PMID:25862940

  2. Stress-Related Cognitive Interference Predicts Cognitive Function in Old Age

    OpenAIRE

    Stawski, Robert S.; Sliwinski, Martin J.; Smyth, Joshua M.; University, Syracuse

    2006-01-01

    Both subjective distress and cognitive interference have been proposed as mechanisms underlying the negative effects of stress on cognition. Studies of aging have shown that distress is associated with lower cognitive performance, but none have examined the effects of cognitive interference. One hundred eleven older adults (Mage = 80) completed measures of working memory, processing speed, and episodic memory as well as self-report measures of subjective distress and cognitive interference. C...

  3. Mechanical behavior of silicon carbide nanoparticles under uniaxial compression

    Energy Technology Data Exchange (ETDEWEB)

    He, Qiuxiang; Fei, Jing; Tang, Chao; Zhong, Jianxin; Meng, Lijun, E-mail: ljmeng@xtu.edu.cn [Xiangtan University, Hunan Key Laboratory for Micro-Nano Energy Materials and Devices, Faculty of School of Physics and Optoelectronics (China)

    2016-03-15

    The mechanical behavior of SiC nanoparticles under uniaxial compression was investigated using an atomic-level compression simulation technique. The results revealed that the mechanical deformation of SiC nanocrystals is highly dependent on compression orientation, particle size, and temperature. A structural transformation from the original zinc-blende to a rock-salt phase is identified for SiC nanoparticles compressed along the [001] direction at low temperature. However, the rock-salt phase is not observed for SiC nanoparticles compressed along the [110] and [111] directions irrespective of size and temperature. The high-pressure-generated rock-salt phase strongly affects the mechanical behavior of the nanoparticles, including their hardness and deformation process. The hardness of [001]-compressed nanoparticles decreases monotonically as their size increases, different from that of [110] and [111]-compressed nanoparticles, which reaches a maximal value at a critical size and then decreases. Additionally, a temperature-dependent mechanical response was observed for all simulated SiC nanoparticles regardless of compression orientation and size. Interestingly, the hardness of SiC nanocrystals with a diameter of 8 nm compressed in [001]-orientation undergoes a steep decrease at 0.1–200 K and then a gradual decline from 250 to 1500 K. This trend can be attributed to different deformation mechanisms related to phase transformation and dislocations. Our results will be useful for practical applications of SiC nanoparticles under high pressure.

  4. Mechanical and morphological evaluation of age-related changes in the Beagle spine

    International Nuclear Information System (INIS)

    Gillett, N.A.; Gerlach, R.; Cassidy, J.; Brown, S.

    1986-01-01

    Age-related changes were evaluated in the spines of Beagle dogs by biomechanical testing, radiology and pathology. Thirty age-matched healthy Beagle dogs were divided into five groups having mean ages of 2, 5, 8, 11, and 14 years. Spinal radiographs of anesthetized dogs were taken prior to euthanasia and on defleshed pines following necropsy. Cervical, thoracic, and lumbar segments were tested in compression to calculate peak stress, peak strain, and elastic modulus. Adjacent spinal segments were examined histologically. Histological evidence of the disc degeneration and changes in the mechanical properties of the intervertebral disc joint preceded radiographical evidence of spondylosis. Changes in the mechanical properties of the disc space were probably a result of the disc degeneration rather than the spondylytic lesions. 3 references, 4 figures

  5. Reactive Molecular Dynamics Simulations to Understand Mechanical Response of Thaumasite under Temperature and Strain Rate Effects.

    Science.gov (United States)

    Hajilar, Shahin; Shafei, Behrouz; Cheng, Tao; Jaramillo-Botero, Andres

    2017-06-22

    Understanding the structural, thermal, and mechanical properties of thaumasite is of great interest to the cement industry, mainly because it is the phase responsible for the aging and deterioration of civil infrastructures made of cementitious materials attacked by external sources of sulfate. Despite the importance, effects of temperature and strain rate on the mechanical response of thaumasite had remained unexplored prior to the current study, in which the mechanical properties of thaumasite are fully characterized using the reactive molecular dynamics (RMD) method. With employing a first-principles based reactive force field, the RMD simulations enable the description of bond dissociation and formation under realistic conditions. From the stress-strain curves of thaumasite generated in the x, y, and z directions, the tensile strength, Young's modulus, and fracture strain are determined for the three orthogonal directions. During the course of each simulation, the chemical bonds undergoing tensile deformations are monitored to reveal the bonds responsible for the mechanical strength of thaumasite. The temperature increase is found to accelerate the bond breaking rate and consequently the degradation of mechanical properties of thaumasite, while the strain rate only leads to a slight enhancement of them for the ranges considered in this study.

  6. 42 CFR 436.308 - Medically needy coverage of individuals under age 21.

    Science.gov (United States)

    2010-10-01

    ... THE VIRGIN ISLANDS Optional Coverage of the Medically Needy § 436.308 Medically needy coverage of... (b) of this section: (1) Who would not be covered under the mandatory medically needy group of... nursing facility services are provided under the plan to individuals within the age group selected under...

  7. Absence of DJ-1 causes age-related retinal abnormalities in association with increased oxidative stress.

    Science.gov (United States)

    Bonilha, Vera L; Bell, Brent A; Rayborn, Mary E; Samuels, Ivy S; King, Anna; Hollyfield, Joe G; Xie, Chengsong; Cai, Huaibin

    2017-03-01

    Oxidative stress alters physiological function in most biological tissues and can lead to cell death. In the retina, oxidative stress initiates a cascade of events leading to focal loss of RPE and photoreceptors, which is thought to be a major contributing factor to geographic atrophy. Despite these implications, the molecular regulation of RPE oxidative stress under normal and pathological conditions remains largely unknown. A better understanding of the mechanisms involved in regulating RPE and photoreceptors oxidative stress response is greatly needed. To this end we evaluated photoreceptor and RPE changes in mice deficient in DJ-1, a protein that is thought to be important in protecting cells from oxidative stress. Young (3 months) and aged (18 months) DJ-1 knockout (DJ-1 KO) and age-matched wild-type mice were examined. In both group of aged mice, scanning laser ophthalmoscopy (SLO) showed the presence of a few autofluorescent foci. The 18 month-old DJ-1 KO retinas were also characterized by a noticeable increase in RPE fluorescence to wild-type. Optical coherence tomography (OCT) imaging demonstrated that all retinal layers were present in the eyes of both DJ-1 KO groups. ERG comparisons showed that older DJ-1 KO mice had reduced sensitivity under dark- and light-adapted conditions compared to age-matched control. Histologically, the RPE contained prominent vacuoles in young DJ-1 KO group with the appearance of enlarged irregularly shaped RPE cells in the older group. These were also evident in OCT and in whole mount RPE/choroid preparations labeled with phalloidin. Photoreceptors in the older DJ-1 KO mice displayed decreased immunoreactivity to rhodopsin and localized reduction in cone markers compared to the wild-type control group. Lower levels of activated Nrf2 were evident in retina/RPE lysates in both young and old DJ-1 KO mouse groups compared to wild-type control levels. Conversely, higher levels of protein carbonyl derivatives and i

  8. Genome-wide association study identifies a single major locus contributing to survival into old age; the APOE locus revisited

    DEFF Research Database (Denmark)

    Deelen, Joris; Beekman, Marian; Uh, Hae-Won

    2011-01-01

    By studying the loci which contribute to human longevity, we aim to identify mechanisms that contribute to healthy aging. To identify such loci, we performed a genome-wide association study (GWAS) comparing 403 unrelated nonagenarians from long-living families included in the Leiden Longevity Stu...

  9. Influence of ageing treatment on microstructure, mechanical and bio-corrosion properties of Mg-Dy alloys.

    Science.gov (United States)

    Yang, Lei; Huang, Yuanding; Feyerabend, Frank; Willumeit, Regine; Kainer, Karl Ulrich; Hort, Norbert

    2012-09-01

    Mg-Dy alloys have shown to be promising for medical applications. In order to investigate the influence of ageing treatment on their mechanical and corrosion properties, three Mg-xDy alloys (x=10, 15, 20 wt%) were prepared. Their microstructure, mechanical and corrosion behavior were investigated. The results indicate that ageing at 250 °C has little influence on the mechanical and corrosion properties. In contrast, ageing at 200 °C significantly increases the yield strength, and reduces the ductility. After ageing at 200 °C, the corrosion rate of Mg-20Dy alloy increases largely in 0.9 wt% NaCl solution, but remains unchanged in cell culture medium. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. The expanding universe of neurotrophic factors: therapeutic potential in aging and age-associated disorders.

    Science.gov (United States)

    Lanni, C; Stanga, S; Racchi, M; Govoni, S

    2010-01-01

    Multiple molecular, cellular, structural and functional changes occur in the brain during aging. Neural cells may respond to these changes adaptively by employing multiple mechanisms in order to maintain the integrity of nerve cell circuits and to facilitate responses to environmental demands. Otherwise, they may succumb to neurodegenerative cascades that result in disorders such as Alzheimer's and Parkinson's diseases. An important role in this balancement is played by neurotrophic factors, which are central to many aspects of nervous system function since they regulate the development, maintenance and survival of neurons and neuron-supporting cells such as glia and oligodendrocytes. A vast amount of evidence indicates that alterations in levels of neurotrophic factors or their receptors can lead to neuronal death and contribute to aging as well as to the pathogenesis of diseases of abnormal trophic support (such as neurodegenerative diseases and depression) and diseases of abnormal excitability (such as epilepsy and central pain sensitization). Cellular and molecular mechanisms by which neurotrophic factors may influence cell survival and excitability are also critically examined to provide novel concepts and targets for the treatment of physiological changes bearing detrimental functional alterations and of different diseases affecting the central nervous system during aging.

  11. Nonlinear Mechanics of MEMS Rectangular Microplates under Electrostatic Actuation

    KAUST Repository

    Saghir, Shahid

    2016-01-01

    The first objective of the dissertation is to develop a suitable reduced order model capable of investigating the nonlinear mechanical behavior of von-Karman plates under electrostatic actuation. The second objective is to investigate the nonlinear

  12. [Cognitive aging mechanism of signaling effects on the memory for procedural sentences].

    Science.gov (United States)

    Yamamoto, Hiroki; Shimada, Hideaki

    2006-08-01

    The aim of this study was to clarify the cognitive aging mechanism of signaling effects on the memory for procedural sentences. Participants were 60 younger adults (college students) and 60 older adults. Both age groups were assigned into two groups; half of each group was presented with procedural sentences with signals that highlighted their top-level structure and the other half with procedural sentences without them. Both groups were requested to perform the sentence arrangement task and the reconstruction task. Each task was composed of procedural sentences with or without signals. Results indicated that signaling supported changes in strategy utilization during the successive organizational processes and that changes in strategy utilization resulting from signaling improved the memory for procedural sentences. Moreover, age-related factors interfered with these signaling effects. This study clarified the cognitive aging mechanism of signaling effects in which signaling supports changes in the strategy utilization during organizational processes at encoding and this mediation promotes memory for procedural sentences, though disuse of the strategy utilization due to aging restrains their memory for procedural sentences.

  13. [Frequency of successful aging and frailty. Associated risk factors].

    Science.gov (United States)

    Carrazco-Peña, Karla Berenice; Farías-Moreno, Katia; Trujillo-Hernández, Benjamín

    To determine the frequency of successful aging (SA) and its relationship with frailty in an elderly population. An analytical cross-sectional study of subjects ≥60 years of age seen as outpatients in a general hospital. Successful aging was defined as scores of ≥ 90 in the Barthel index and ≤ 2 in the Pfeiffer test. Frailty was determined using the Fried criteria. The study included 400 subjects (272 women and 128 men), with a mean age of 71.6±8.2 years. The SA frequency was 40.4%. frail status was statistically higher in non-successful aging subjects than in SA subjects (161.7 versus 7.9%; P<.001). Women were more frequently frail, while being a pensioner/retired and married were associated less frequently with frailty. Successful aging is associated with a lower level of frailty. Copyright © 2017 SEGG. Publicado por Elsevier España, S.L.U. All rights reserved.

  14. 29 CFR 780.321 - Minors 16 years of age or under.

    Science.gov (United States)

    2010-07-01

    ... Employment in Agriculture That Is Exempted From the Minimum Wage and Overtime Pay Requirements Under Section... years of age and the employer must pay to such an employee the applicable statutory minimum wage unless..., although section 13(a)(6)(D) provides a minimum wage and overtime exemption for minors 16 years of age or...

  15. Filter-adsorber aging assessment

    Energy Technology Data Exchange (ETDEWEB)

    Winegardner, W.K. [Pacific Northwest Laboratory, Richland, WA (United States)

    1995-02-01

    An aging assessment of high-efficiency particulate (HEPA) air filters and activated carbon gas adsorption units was performed by the Pacific Northwest Laboratory as part of the U.S. Nuclear Regulatory Commission`s (USNRC) Nuclear Plant Aging Research (NPAR) Program. This evaluation of the general process in which characteristics of these two components gradually change with time or use included the compilation of information concerning failure experience, stressors, aging mechanisms and effects, and inspection, surveillance, and monitoring methods (ISMM). Stressors, the agents or stimuli that can produce aging degradation, include heat, radiation, volatile contaminants, and even normal concentrations of aerosol particles and gasses. In an experimental evaluation of degradation in terms of the tensile breaking strength of aged filter media specimens, over forty percent of the samples did not meet specifications for new material. Chemical and physical reactions can gradually embrittle sealants and gaskets as well as filter media. Mechanisms that can lead to impaired adsorber performance are associated with the loss of potentially available active sites as a result of the exposure of the carbon to airborne moisture or volatile organic compounds. Inspection, surveillance, and monitoring methods have been established to observe filter pressure drop buildup, check HEPA filters and adsorbers for bypass, and determine the retention effectiveness of aged carbon. These evaluations of installed filters do not reveal degradation in terms of reduced media strength but that under normal conditions aged media can continue to effectively retain particles. However, this degradation may be important when considering the likelihood of moisture, steam, and higher particle loadings during severe accidents and the fact it is probable that the filters have been in use for an extended period.

  16. Aging-induced dysregulation of dicer1-dependent microRNA expression impairs angiogenic capacity of rat cerebromicrovascular endothelial cells.

    Science.gov (United States)

    Ungvari, Zoltan; Tucsek, Zsuzsanna; Sosnowska, Danuta; Toth, Peter; Gautam, Tripti; Podlutsky, Andrej; Csiszar, Agnes; Losonczy, Gyorgy; Valcarcel-Ares, M Noa; Sonntag, William E; Csiszar, Anna

    2013-08-01

    Age-related impairment of angiogenesis is likely to play a central role in cerebromicrovascular rarefaction and development of vascular cognitive impairment, but the underlying mechanisms remain elusive. To test the hypothesis that dysregulation of Dicer1 (ribonuclease III, a key enzyme of the microRNA [miRNA] machinery) impairs endothelial angiogenic capacity in aging, primary cerebromicrovascular endothelial cells (CMVECs) were isolated from young (3 months old) and aged (24 months old) Fischer 344 × Brown Norway rats. We found an age-related downregulation of Dicer1 expression both in CMVECs and in small cerebral vessels isolated from aged rats. In aged CMVECs, Dicer1 expression was increased by treatment with polyethylene glycol-catalase. Compared with young cells, aged CMVECs exhibited altered miRNA expression profile, which was associated with impaired proliferation, adhesion to vitronectin, collagen and fibronectin, cellular migration (measured by a wound-healing assay using electric cell-substrate impedance sensing technology), and impaired ability to form capillary-like structures. Overexpression of Dicer1 in aged CMVECs partially restored miRNA expression profile and significantly improved angiogenic processes. In young CMVECs, downregulation of Dicer1 (siRNA) resulted in altered miRNA expression profile associated with impaired proliferation, adhesion, migration, and tube formation, mimicking the aging phenotype. Collectively, we found that Dicer1 is essential for normal endothelial angiogenic processes, suggesting that age-related dysregulation of Dicer1-dependent miRNA expression may be a potential mechanism underlying impaired angiogenesis and cerebromicrovascular rarefaction in aging.

  17. The unified mechanism of aging effects in both martensite and parent phase for shape-memory alloys: atomic-level simulations

    Science.gov (United States)

    Deng, J.; Ding, X.; Suzuki, T.; Otsuka, K.; Lookman, T.; Saxena, A.; Sun, J.; Ren, X.

    2011-03-01

    Most shape-memory alloys (SMAs) subject to the aging effects not only in the martensite phase but also in the parent phase. These aging effects have been attracted much attention as they strongly affect the practical applications of SMAs. So far, the intrinsic mechanism of them has remained controversial due to the difficulty in visualization of what happens in atomic scale. In the present study, by using a combination of molecular dynamics method and Monte-Carlo method [1], we investigate the aging effects in both martensite and parent phase. We successfully reproduced the thermal behaviors of aging effects for SMAs, i.e., the Af temperature increase with aging time in martensite and the Ms temperature decrease with aging time in parent phase, which keep good agreement with the experimental observations [2]. In addition, quantitative analysis of the atomic configurations during aging reveals that the aging effects are not associated with a change in the average structure.

  18. Association between age at onset of psychosis and age at onset of cannabis use in non-affective psychosis.

    Science.gov (United States)

    Galvez-Buccollini, Juan A; Proal, Ashley C; Tomaselli, Veronica; Trachtenberg, Melissa; Coconcea, Cristinel; Chun, Jinsoo; Manschreck, Theo; Fleming, Jerry; Delisi, Lynn E

    2012-08-01

    Several studies have associated cannabis use with the development of schizophrenia. However, it has been difficult to disentangle the effects of cannabis from that of other illicit drugs, as previous studies have not evaluated pure cannabis users. To test whether the onset of cannabis use had an effect on the initiation of psychosis, we examined the time relationship between onset of use and onset of psychosis, restricting our analysis to a cohort of individuals who only used cannabis and no other street drugs. Fifty-seven subjects with non-affective psychoses who used cannabis prior to developing a psychosis were interviewed using the Diagnostic Interview for Genetic Studies (DIGS). The Family Interview for Genetic Studies (FIGS) was also used to interview a family informant about psychiatric illness in the patient and the entire family. Multiple linear regression techniques were used to estimate the association between variables. After adjusting for potential confounding factors such as sex, age, lifetime diagnosis of alcohol abuse or dependence, and family history of schizophrenia, the age at onset of cannabis was significantly associated with age at onset of psychosis (β=0.4, 95% CI=0.1-0.7, p=0.004) and age at first hospitalization (β=0.4, 95% CI=0.1-0.8, p=0.008). The mean time between beginning to use cannabis and onset of psychosis was 7.0±4.3. Age at onset of alcohol use was not associated with age at onset of psychosis or age at first hospitalization. Age at onset of cannabis is directly associated with age at onset of psychosis and age at first hospitalization. These associations remain significant after adjusting for potential confounding factors and are consistent with the hypothesis that cannabis could cause or precipitate the onset of psychosis after a prolonged period of time. Published by Elsevier B.V.

  19. Aging research

    International Nuclear Information System (INIS)

    Ross, D.F. Jr.

    1988-01-01

    The USNRC Office of Nuclear Regulatory Research has developed a program for nuclear plant aging research (NPAR) to achieve an understanding of nuclear plant aging, its potential effects on safety, and methods for its detection and mitigation, sufficient for addressing safety and regulatory issues and supporting regulatory decisions on issues. Specifically, the NRC has aggressive research and regulatory programs associated with aging effects on piping, steam generators, containments, structures, and electrical and mechanical systems and components. In addition to safety assessment for the original license period for nuclear power plants, this aging information will be extremely useful in providing technical bases for efficient and effective regulation associated with possible license extension. This paper discusses the major activities of USNRC sponsored aging research program and recommends an approach to manage and handle aging at nuclear power plants

  20. THE CHILD OFFENDER UNDER THE AGE OF CRIMINAL LIABILITY

    Directory of Open Access Journals (Sweden)

    Niculina KARACSONY

    2015-04-01

    Full Text Available At European level crime among children represents a contemporary issue and in Romania, the philosophy of the new penal code approved by Law No 286/2009 is shaped around punishment. Prevention policy in Romania and juvenile justice objectives relative to age criteria outlines two different legal manners to address children's liability under the law. One is targeting the category of children between 0 and 14 years of age, which consideres the absolute inability of criminal responsibility and one that provides criminal liability starting from the age of 14. The sensitivity of the issue of children involved in unlawfull acts and the inventory of responses to it brought me to the necessity of research the types of approach and diversity of social services built around this target group.

  1. Modeling of the mechanical behavior of austenitic stainless steels under pure fatigue and fatigue relaxation loadings

    International Nuclear Information System (INIS)

    Hajjaji-Rachdi, Fatima

    2015-01-01

    Austenitic stainless steels are potential candidates for structural components of sodium-cooled fast neutron reactors. Many of these components will be subjected to cyclic loadings including long hold times (1 month) under creep or relaxation at high temperature. These hold times are unattainable experimentally. The aim of the present study is to propose mechanical models which take into account the involved mechanisms and their interactions during such complex loadings. First, an experimental study of the pure fatigue and fatigue-relaxation behavior of 316L(N) at 500 C has been carried out with very long hold times (10 h and 50 h) compared with the ones studied in literature. Tensile tests at 600 C with different applied strain rates have been undertaken in order to study the dynamic strain ageing phenomenon. Before focusing on more complex loadings, the mean field homogenization approach has been used to predict the mechanical behavior of different FCC metals and alloys under low cycle fatigue at room temperature. Both Hill-Hutchinson and Kroener models have been used. Next, a physically-based model based on dislocation densities has been developed and its parameters measured. The model allows predictions in a qualitative agreement with experimental data for tensile loadings. Finally, this model has been enriched to take into account visco-plasticity, dislocation climb and interaction between dislocations and solute atoms, which are influent during creep-fatigue or fatigue relaxation at high temperature. The proposed model uses three adjustable parameters only and allows rather accurate prediction of the behavior of 316L(N) steel under tensile loading and relaxation. (author) [fr

  2. Understanding of carbon-based supercapacitors ageing mechanisms by electrochemical and analytical methods

    Science.gov (United States)

    Liu, Yinghui; Soucaze-Guillous, Benoît; Taberna, Pierre-Louis; Simon, Patrice

    2017-10-01

    In order to shed light on ageing mechanisms of Electrochemical Double Layer Capacitor (EDLC), two kinds of activated carbons are studied in tetraethyl ammonium tetrafluoroborate (Et4NBF4) in acetonitrile. In floating mode, it turns out that two different ageing mechanisms are observed, depending on the activated carbon electrode materials used. On one hand, carbon A exhibits a continuous capacitance and series resistance fall-off; on the other hand, for carbon B, only the series resistance degrades after ageing while the capacitance keeps unchanged. Additional electrochemical characterizations (Electrochemical Impedance Spectroscopy - EIS - and diffusion coefficient calculations) were carried out showing that carbon A's ageing behavior is suspected to be primarily related to the carbon degradation while for carbon B a passivation occurs leading to the formation of a Solid Electrolyte Interphase-Like (SEI-L) film. These hypotheses are supported by TG-IR and Raman spectroscopy analysis. The outcome forms the latter is an increase of carbon defects on carbon A on positive electrode.

  3. Etiology and Factors Associated with Pneumonia in Children under 5 Years of Age in Mali: A Prospective Case-Control Study

    Science.gov (United States)

    Messaoudi, Mélina; Sánchez Picot, Valentina; Telles, Jean-Noël; Diakite, Abdoul-Aziz; Komurian-Pradel, Florence; Endtz, Hubert; Diallo, Souleymane; Paranhos-Baccalà, Gláucia; Vanhems, Philippe

    2015-01-01

    Background There are very limited data on children with pneumonia in Mali. The objective was to assess the etiology and factors associated with community-acquired pneumonia in hospitalized children pneumonia; Controls were hospitalized children without respiratory features, matched for age and period. Respiratory specimens, were collected to identify 19 viruses and 5 bacteria. Whole blood was collected from cases only. Factors associated with pneumonia were assessed by multivariate logistic regression. Results Overall, 118 cases and 98 controls were analyzed; 44.1% were female, median age was 11 months. Among pneumonia cases, 30.5% were hypoxemic at admission, mortality was 4.2%. Pneumonia cases differed from the controls regarding clinical signs and symptoms but not in terms of past medical history. Multivariate analysis of nasal swab findings disclosed that S. pneumoniae (adjusted odds ratio [aOR] = 3.4, 95% confidence interval [95% CI]: 1.6–7.0), human metapneumovirus (aOR = 17.2, 95% CI: 2.0–151.4), respiratory syncytial virus [RSV] (aOR = 7.4, 95% CI: 2.3–23.3), and influenza A virus (aOR = 10.7, 95% CI: 1.0–112.2) were associated with pneumonia, independently of patient age, gender, period, and other pathogens. Distribution of S. pneumoniae and RSV differed by season with higher rates of S. pneumoniae in January-June and of RSV in July-September. Pneumococcal serotypes 1 and 5 were more frequent in pneumonia cases than in the controls (P = 0.009, and P = 0.04, respectively). Conclusions In this non-PCV population from Mali, pneumonia in children was mainly attributed to S. pneumoniae, RSV, human metapneumovirus, and influenza A virus. Increased pneumococcal conjugate vaccine coverage in children could significantly reduce the burden of pneumonia in sub-Saharan African countries. PMID:26696249

  4. Diagnostic criteria for severe acute malnutrition among infants aged under 6 mo.

    Science.gov (United States)

    Mwangome, Martha; Ngari, Moses; Fegan, Greg; Mturi, Neema; Shebe, Mohammed; Bauni, Evasius; Berkley, James A

    2017-06-01

    Background: There is an increasing recognition of malnutrition among infants under 6 mo of age (U6M). Current diagnosis criteria use weight-for-length z scores (WLZs), but the 2006 WHO standards exclude infants shorter than 45 cm. In older children, midupper arm circumference (MUAC) predicts mortality better than does WLZ. Outcomes may also be influenced by exposure to HIV and size or gestational age at birth. Diagnostic thresholds for WLZ, MUAC, and other indexes have not been fully evaluated against mortality risk among U6M infants. Objective: The aim was to determine the association of anthropometric indexes with risks of inpatient and postdischarge mortality among U6M infants recruited at the time of hospitalization. Design: We analyzed data from a cohort of U6M infants admitted to Kilifi County Hospital (2007-2013), Kenya. The primary outcomes were inpatient death and death during follow-up over 1 y after discharge. We calculated adjusted RRs for inpatient mortality and HRs for postdischarge mortality for different anthropometric measures and thresholds. Discriminatory value was assessed by using receiver operating characteristic curves. Results: A total of 2882 infants were admitted: 140 (4.9%) died in the hospital and 1405 infants were followed up after discharge. Of these, 75 (5.3%) died within 1 y during 1318 child-years of observation. MUAC and weight-for-age z score (WAZ) predicted inpatient and postdischarge mortality better than did WLZ ( P 0.05) and performed better than WLZ <-3 for both inpatient and postdischarge mortality (both P < 0.001). Reported small size at birth did not reduce the risk of death associated with anthropometric indexes. Conclusions: U6M infants at the highest risk of death are best targeted by using MUAC or WAZ. Further research into the effectiveness of potential interventions is required.

  5. The changes of gut microbiota associated with age and lifestyle

    Directory of Open Access Journals (Sweden)

    Lilit Vanikovna Egshatyan

    2015-02-01

    Full Text Available In this review are discussed experimental and clinical data about the role of gut microbiota and its changes associated with age and lifestyle. The large intestinal microbiota plays an important role in normal bowel function and the maintenance of host health through the formation of short chain fatty acids, modulation of immune system reactivity, and development of colonization resistance. The intestinal microflora is a peculiar indicator of the condition of a microorganism reacting to age, physiological, dietary, and geographical factors from change of qualitative and quantitative structure. Studies have demonstrated that obesity and metabolic syndrome may be associated with profound microbiotal changes. Changes in gut microbiota control metabolic endotoxemia - induced chronic inflammation, oxidative stress, and metabolic disorder which are connected with the increased risk of development of cardiovascular diseases and pathology associated with age, which leads to accelerated aging. It is obvious that maintenance of a homeostasis and a normal metabolism is impossible without restoration of a variety of normal associations of intestinal microorganisms.

  6. Uncovering the Mechanisms Responsible for Why Language Learning May Promote Healthy Cognitive Aging

    Directory of Open Access Journals (Sweden)

    Mark Antoniou

    2017-12-01

    Full Text Available One of the great challenges facing humankind in the 21st century is preserving healthy brain function in our aging population. Individuals over 60 are the fastest growing age group in the world, and by 2050, it is estimated that the number of people over the age of 60 will triple. The typical aging process involves cognitive decline related to brain atrophy, especially in frontal brain areas and regions that subserve declarative memory, loss of synaptic connections, and the emergence of neuropathological symptoms associated with dementia. The disease-state of this age-related cognitive decline is Alzheimer’s disease and other dementias, which may cause older adults to lose their independence and rely on others to live safely, burdening family members and health care systems in the process. However, there are two lines of research that offer hope to those seeking to promote healthy cognitive aging. First, it has been observed that lifestyle variables such as cognitive leisure activities can moderate the risk of Alzheimer’s disease, which has led to the development of plasticity-based interventions for older adults designed to protect against the adverse effects of cognitive decline. Second, there is evidence that lifelong bilingualism acts as a safeguard in preserving healthy brain function, possibly delaying the incidence of dementia by several years. In previous work, we have suggested that foreign language learning programs aimed at older populations are an optimal solution for building cognitive reserve because language learning engages an extensive brain network that is known to overlap with the regions negatively affected by the aging process. Here, we will outline potential future lines of research that may uncover the mechanism responsible for the emergence of language learning related brain advantages, such as language typology, bi- vs. multi-lingualism, age of acquisition, and the elements that are likely to result in the largest

  7. Uncovering the Mechanisms Responsible for Why Language Learning May Promote Healthy Cognitive Aging

    Science.gov (United States)

    Antoniou, Mark; Wright, Sarah M.

    2017-01-01

    One of the great challenges facing humankind in the 21st century is preserving healthy brain function in our aging population. Individuals over 60 are the fastest growing age group in the world, and by 2050, it is estimated that the number of people over the age of 60 will triple. The typical aging process involves cognitive decline related to brain atrophy, especially in frontal brain areas and regions that subserve declarative memory, loss of synaptic connections, and the emergence of neuropathological symptoms associated with dementia. The disease-state of this age-related cognitive decline is Alzheimer’s disease and other dementias, which may cause older adults to lose their independence and rely on others to live safely, burdening family members and health care systems in the process. However, there are two lines of research that offer hope to those seeking to promote healthy cognitive aging. First, it has been observed that lifestyle variables such as cognitive leisure activities can moderate the risk of Alzheimer’s disease, which has led to the development of plasticity-based interventions for older adults designed to protect against the adverse effects of cognitive decline. Second, there is evidence that lifelong bilingualism acts as a safeguard in preserving healthy brain function, possibly delaying the incidence of dementia by several years. In previous work, we have suggested that foreign language learning programs aimed at older populations are an optimal solution for building cognitive reserve because language learning engages an extensive brain network that is known to overlap with the regions negatively affected by the aging process. Here, we will outline potential future lines of research that may uncover the mechanism responsible for the emergence of language learning related brain advantages, such as language typology, bi- vs. multi-lingualism, age of acquisition, and the elements that are likely to result in the largest gains. PMID:29326636

  8. Monitoring and modeling the aging mechanisms

    International Nuclear Information System (INIS)

    Le Pape, Yann; Courtois, Alexis; Ghavamian, Charles

    2006-09-01

    origin of these cracks might be caused by differential drying shrinkage for the cracks near the raft and by deviated post-tensioning near the material hatch. The bi-directional prestress limits the cracks opening when the containment is over-pressurized. However, under sustained loads, concrete creep leads to a loss of prestress due to the deformation compatibility between the grouted tendons the concrete mass. Thus the safety margin shall be affected since cracks opening may become larger with time. In order to optimize the extent of reparation, it is therefore compulsory to improve the prediction of the long-time mechanical behavior of the containment. This task requires: - the improvement of the delayed behavior understanding, the so-called aging mechanism, the development of realistic, i.e. less conservative, models specifically designed for the very specific loading conditions of the inner containment; - the integration of monitored data in the numerical or analytical simulation; - the evaluation of the impact of the concrete damage and the loss of prestress on the hydraulic behavior. The paper addresses the following items: inner containment description and in-situ monitoring; concrete shrinkage and creep modeling; laboratory testing; numerical computation and comparison with monitored data; introducing monitored data in the computation; impact of damage on the leak tightness of the containment wall. The communication illustrates the general strategy adopted by EDF in order to assess the long-term integrity of NPP inner concrete containment vessel. All analysis and computation are performed on the standard zone of the concrete vessel. On-going research and development programs are focused on the refinement of the methodology and their application to more realistic numerical model of large-scale structure

  9. Age-specific association between percent body fat and pulmonary ...

    African Journals Online (AJOL)

    This study describes the association between percent body fat and pulmonary function among apparently normal twenty male children tidal volume aged 4 years and twenty male children aged 10 years in Ogbomoso. The mean functional residual capacity of the lung in male children aged 10 years was significantly higher ...

  10. Biology of Healthy Aging and Longevity.

    Science.gov (United States)

    Carmona, Juan José; Michan, Shaday

    2016-01-01

    As human life expectancy is prolonged, age-related diseases are thriving. Aging is a complex multifactorial process of molecular and cellular decline that affects tissue function over time, rendering organisms frail and susceptible to disease and death. Over the last decades, a growing body of scientific literature across different biological models, ranging from yeast, worms, flies, and mice to primates, humans and other long-lived animals, has contributed greatly towards identifying conserved biological mechanisms that ward off structural and functional deterioration within living systems. Collectively, these data offer powerful insights into healthy aging and longevity. For example, molecular integrity of the genome, telomere length, epigenetic landscape stability, and protein homeostasis are all features linked to "youthful" states. These molecular hallmarks underlie cellular functions associated with aging like mitochondrial fitness, nutrient sensing, efficient intercellular communication, stem cell renewal, and regenerative capacity in tissues. At present, calorie restriction remains the most robust strategy for extending health and lifespan in most biological models tested. Thus, pathways that mediate the beneficial effects of calorie restriction by integrating metabolic signals to aging processes have received major attention, such as insulin/insulin growth factor-1, sirtuins, mammalian target of rapamycin, and 5' adenosine monophosphate-activated protein kinase. Consequently, small-molecule targets of these pathways have emerged in the impetuous search for calorie restriction mimetics, of which resveratrol, metformin, and rapamycin are the most extensively studied. A comprehensive understanding of the molecular and cellular mechanisms that underlie age-related deterioration and repair, and how these pathways interconnect, remains a major challenge for uncovering interventions to slow human aging while extending molecular and physiological youthfulness

  11. Underlying mechanisms of improving physical activity behavior after rehabilitation

    NARCIS (Netherlands)

    van der Ploeg, H.P.; Streppel, K.R.; van der Beek, A.J.; van der Woude, L.H.V.; van Harten, W.H.; van Mechelen, W.

    2008-01-01

    Background: Regular physical activity is beneficial for the health and functioning of people with a disability. Effective components of successful physical activity promotion interventions should be identified and disseminated. Purpose: To study the underlying mechanisms of the combined sport

  12. Underlying Mechanisms of Improving Physical Activity Behavior after Rehabilitation

    NARCIS (Netherlands)

    van der Ploeg, Hidde P.; Streppel, Kitty R.M.; van der Beek, Allard J.; Woude, Luc H.V.; van Harten, Willem H.; Vollenbroek-Hutten, Miriam Marie Rosé; van Mechelen, Willem

    2008-01-01

    Background: Regular physical activity is beneficial for the health and functioning of people with a disability. Effective components of successful physical activity promotion interventions should be identified and disseminated. Purpose: To study the underlying mechanisms of the combined sport

  13. Review of effects of long-term aging on the mechanical properties and microstructures of Types 304 and 316 stainless steel

    International Nuclear Information System (INIS)

    Horak, J.A.; Sikka, V.K.; Raske, D.T.

    1985-01-01

    Because commercial liquid metal fast breeder reactor (LMFBR) are designed to last for 40 years or more, an understanding of the mechanical behavior of the structural alloys used in them is required for times on the order of 2.5 x 10 5 h (assuming a 70% availability factor). Types 304 and 316 stainless steel are used extensively in LMFBR systems. At the beginning of life these alloys are in a metastable state and evolve to a more stable state and, therefore, more stable microstructure during plant operation. Correlations of microstructures and mechanical properties during aging under representative LMFBR temperature and loading conditions are desirable from the standpoint of assuring safe, reliable, and economic plant operation. We reviewed the mechanical properties and microstructures of types 304 and 316 stainless steel wrought alloys after long-term aging in air for times up to 9 x 10 4 h (about 10-1/2 years). The principal effect of such aging is to reduce low temperature fracture toughness (as measured by Charpy impact test) and tensile ductility. Examples are cited, however, where, because stable microstructures are achieved, these as well as strength-related properties can be expected to remain adequate for anticipated service life conditions. 16 refs., 19 figs

  14. Factors associated with active aging in Finland, Poland, and Spain.

    Science.gov (United States)

    Perales, Jaime; Martin, Steven; Ayuso-Mateos, Jose Luis; Chatterji, Somnath; Garin, Noe; Koskinen, Seppo; Leonardi, Matilde; Miret, Marta; Moneta, Victoria; Olaya, Beatriz; Tobiasz-Adamczyk, Beata; Haro, Josep Maria

    2014-08-01

    Continuous population aging has raised international policy interest in promoting active aging (AA). AA theoretical models have been defined from a biomedical or a psychosocial perspective. These models may be expanded including components suggested by lay individuals. This paper aims to study the correlates of AA in three European countries, namely, Spain, Poland, and Finland using four different definitions of AA. The EU COURAGE in Europe project was a cross-sectional general adult population survey conducted in a representative sample of the noninstitutionalized population of Finland, Poland, and Spain. Participants (10,800) lived in the community. This analysis focuses on individuals aged 50 years old and over (7,987). Four definitions (two biomedical, one psychosocial, and a complete definition including biomedical, psychosocial, and external variables) of AA were analyzed. Differences in AA were found for country, age, education, and occupation. Finland scored consistently the highest in AA followed by Spain and Poland. Younger age was associated with higher AA. Higher education and occupation was associated with AA. Being married or cohabiting was associated with better AA compared to being widowed or separated in most definitions. Gender and urbanicity were not associated with AA, with few exceptions. Men scored higher in AA only in Spain, whereas there was no gender association in the other two countries. Being widowed was only associated with lower AA in Poland and not being married was associated with lower AA in Poland and Finland but not Spain. Associations with education, marital status, and occupation suggest that these factors are the most important components of AA. These association patterns, however, seem to vary across the three countries. Actions to promote AA in these countries may be addressed at reducing inequalities in occupation and education or directly tackling the components of AA lacking in each country.

  15. Aging and ABO blood type influence von Willebrand factor and factor VIII levels through interrelated mechanisms.

    Science.gov (United States)

    Albánez, S; Ogiwara, K; Michels, A; Hopman, W; Grabell, J; James, P; Lillicrap, D

    2016-05-01

    Essentials von Willebrand factor (VWF) and factor VIII (FVIII) levels are modulated by age and ABO status. The effect of aging and ABO blood type on VWF and FVIII was assessed in 207 normal individuals. Aging and ABO blood type showed combined and bidirectional influences on VWF and FVIII levels. Aging and ABO blood type influence VWF levels through both secretion and clearance mechanisms. Background The effect of aging and ABO blood type on plasma levels of von Willebrand factor (VWF) and factor VIII (FVIII) have been widely reported; however, a comprehensive analysis of their combined effect has not been performed and the mechanisms responsible for the age-related changes have not been determined. Objectives To assess the influence of aging and ABO blood type on VWF and FVIII levels, and to evaluate the contribution of VWF secretion and clearance to the age-related changes. Methods A cross-sectional observational study was performed in a cohort of 207 normal individuals, whose levels of VWF, FVIII, VWF propeptide (VWFpp), VWFpp/VWF:Ag ratio and blood type A antigen content on VWF (A-VWF) were quantified. Results Aging and ABO blood type exerted interrelated effects on VWF and FVIII plasma levels, because the age-related increase in both proteins was significantly higher in type non-O individuals (β = 0.011 vs. 0.005). This increase with age<