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Sample records for accelerated aging protocol

  1. A methodology for examining the plausibility of accelerated aging protocols for UHMWPE components.

    PubMed

    Lewis, G; Nyman, J S; Trieu, H H

    1998-01-01

    In light of the time-intensive nature of using real-time shelf-aged specimens in research into property changes of ultra-high-molecular-weight polyethylene (UHMWPE), accelerated thermal diffusion oxidative aging (usually referred to as accelerated aging) is frequently resorted to. A number of such aging protocols have been reported in the literature, with various claims for their producing changes in the properties of the polymer being the same as or similar to those seen in real-time shelf-aged samples. The thrust of the present work is the presentation of a methodology for examining such claims. The methodology is applied to six properties (% crystallinity, melting temperature, oxidation index, ultimate tensile strength, ultimate tensile elongation, and tensile toughness) of 4150HP UHMWPE grade, sterilized using six different methods, prior to and following the use of a specific accelerated aging protocol (oxygen gas at 70 degrees C and 507 kPa pressure; 14 d.). These six properties have been identified in the literature as being strongly correlated with the clinical wear of UHMWPE articular components. It is shown that the claim for the protocol used in the present work (in terms of the simulated equivalent shelf aging time) is plausible. It needs to be emphasized, however, that this conclusion is tentative given the paucity of the relevant literature results that are currently available and which are vital to the application of the methodology.

  2. Effect of an accelerated aging protocol on viscoelastic properties of UHMWPE.

    PubMed

    Lewis, Gladius

    2002-01-01

    The values of two viscoelastic properties (storage modulus and loss angle) of four sets of ultra-high-molecular-weight polyethylene specimens were obtained. Two sets comprised specimens that had been sterilized (using gamma radiation in air or ethylene oxide gas) while the other two sets comprised specimens that were sterilized and then exposed to an accelerated aging protocol that, in the literature, has been proposed as simulating 5 years of real-time shelf aging. An analysis of the present results from the four specimen sets and those obtained, in a previous study by the present author, on specimens machined from real-time shelf aged tibial inserts suggests that the claim made for the accelerated aging protocol may be conservative.

  3. Colour stability of denture teeth submitted to different cleaning protocols and accelerated artificial aging.

    PubMed

    Freire, T S; Aguilar, F G; Garcia, L da Fonseca Roberti; Pires-de-Souza, F de Carvalho Panzeri

    2014-03-01

    Acrylic resin is widely used for artificial teeth manufacturing due to several important characteristics; however, this material do not present acceptable colour stability over the course of time. This study evaluated the effect of different cleaning protocols and accelerated artificial aging on colour stability of denture teeth made of acrylic resin. Sixty denture teeth in dark and light shades were used, and separated according to the treatment to which they were submitted. Results demonstrated that colour stability of artificial teeth is influenced by the cleaning solution and artificial aging, being dark teeth more susceptible to colour alteration than lighter ones.

  4. Resin composite characterizations following a simplified protocol of accelerated aging as a function of the expiration date.

    PubMed

    D'Alpino, Paulo Henrique Perlatti; Vismara, Marcus Vinícius Gonçalves; Mello, Luciano Marcelo de Medeiros; Di Hipólito, Vinicius; González, Alejandra Hortencia Miranda; Graeff, Carlos Frederico de Oliveira

    2014-07-01

    This study evaluated the mechanical, thermal, and morphological characteristics of different classifications of dental composites as a function of the material condition (new, aged and expired). Specimens were obtained according to these factors: Composites: Filtek P60, Filtek Z250, Filtek Z350XT, and Filtek Silorane; and Material conditions: new, aged, and expired. The syringe composites underwent an accelerated aging protocol (Arrhenius model). The flexural strength (FS) and flexural modulus (E) were obtained. The thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were also performed and the glass transition temperature (Tg) and the weight loss calculated. Topographic analysis of the composites was performed under SEM. The material conditions influenced the mechanical properties of the composites. The silorane composite exhibited a characteristic thermal behavior different from that of the methacrylates. In general, the Tg increased after the accelerated aging protocol and decreased for expired ones, compared to the new composites. A significant increase in FS of Filtek Z350XT after aging was accompanied by an increase in the Tg. The filler packings were in accordance with the manufacture׳s information. The topographic aspects of the composites were modified as a function of the material condition. The mechanical properties of the composites following a simplified protocol of accelerated aging varied as a function of the expiration date. The silorane composite presented a characteristic thermal behavior. Although the dental manufacturers may not be able to control variables as storage temperature and transportation conditions, these effects on the composite clinical performance can be minimized if properly considered.

  5. Menopause accelerates biological aging.

    PubMed

    Levine, Morgan E; Lu, Ake T; Chen, Brian H; Hernandez, Dena G; Singleton, Andrew B; Ferrucci, Luigi; Bandinelli, Stefania; Salfati, Elias; Manson, JoAnn E; Quach, Austin; Kusters, Cynthia D J; Kuh, Diana; Wong, Andrew; Teschendorff, Andrew E; Widschwendter, Martin; Ritz, Beate R; Absher, Devin; Assimes, Themistocles L; Horvath, Steve

    2016-08-16

    Although epigenetic processes have been linked to aging and disease in other systems, it is not yet known whether they relate to reproductive aging. Recently, we developed a highly accurate epigenetic biomarker of age (known as the "epigenetic clock"), which is based on DNA methylation levels. Here we carry out an epigenetic clock analysis of blood, saliva, and buccal epithelium using data from four large studies: the Women's Health Initiative (n = 1,864); Invecchiare nel Chianti (n = 200); Parkinson's disease, Environment, and Genes (n = 256); and the United Kingdom Medical Research Council National Survey of Health and Development (n = 790). We find that increased epigenetic age acceleration in blood is significantly associated with earlier menopause (P = 0.00091), bilateral oophorectomy (P = 0.0018), and a longer time since menopause (P = 0.017). Conversely, epigenetic age acceleration in buccal epithelium and saliva do not relate to age at menopause; however, a higher epigenetic age in saliva is exhibited in women who undergo bilateral oophorectomy (P = 0.0079), while a lower epigenetic age in buccal epithelium was found for women who underwent menopausal hormone therapy (P = 0.00078). Using genetic data, we find evidence of coheritability between age at menopause and epigenetic age acceleration in blood. Using Mendelian randomization analysis, we find that two SNPs that are highly associated with age at menopause exhibit a significant association with epigenetic age acceleration. Overall, our Mendelian randomization approach and other lines of evidence suggest that menopause accelerates epigenetic aging of blood, but mechanistic studies will be needed to dissect cause-and-effect relationships further. PMID:27457926

  6. The Interplanetary Overlay Networking Protocol Accelerator

    NASA Technical Reports Server (NTRS)

    Pang, Jackson; Torgerson, Jordan L.; Clare, Loren P.

    2008-01-01

    A document describes the Interplanetary Overlay Networking Protocol Accelerator (IONAC) an electronic apparatus, now under development, for relaying data at high rates in spacecraft and interplanetary radio-communication systems utilizing a delay-tolerant networking protocol. The protocol includes provisions for transmission and reception of data in bundles (essentially, messages), transfer of custody of a bundle to a recipient relay station at each step of a relay, and return receipts. Because of limitations on energy resources available for such relays, data rates attainable in a conventional software implementation of the protocol are lower than those needed, at any given reasonable energy-consumption rate. Therefore, a main goal in developing the IONAC is to reduce the energy consumption by an order of magnitude and the data-throughput capability by two orders of magnitude. The IONAC prototype is a field-programmable gate array that serves as a reconfigurable hybrid (hardware/ firmware) system for implementation of the protocol. The prototype can decode 108,000 bundles per second and encode 100,000 bundles per second. It includes a bundle-cache static randomaccess memory that enables maintenance of a throughput of 2.7Gb/s, and an Ethernet convergence layer that supports a duplex throughput of 1Gb/s.

  7. Terrestrial Photovoltaic Module Accelerated Test-To-Failure Protocol

    SciTech Connect

    Osterwald, C. R.

    2008-03-01

    This technical report documents a test-to-failure protocol that may be used to obtain quantitative information about the reliability of photovoltaic modules using accelerated testing in environmental temperature-humidity chambers.

  8. Association between different risk factors and vascular accelerated ageing (EVA study): study protocol for a cross-sectional, descriptive observational study

    PubMed Central

    Gomez-Marcos, Manuel A; Martinez-Salgado, Carlos; Gonzalez-Sarmiento, Rogelio; Hernandez-Rivas, Jesus Ma; Sanchez-Fernandez, Pedro L; Recio-Rodriguez, Jose I; Rodriguez-Sanchez, Emiliano; García-Ortiz, Luis

    2016-01-01

    Introduction The process of population ageing that is occurring in developed societies represents a major challenge for the health system. The aim of this study is to analyse factors that have an influence on early vascular ageing (EVA), estimated by carotid-femoral pulse wave velocity (cf-PWV) and Cardio Ankle Vascular Index (CAVI), and to determine differences by gender in a Spanish population. Methods and analysis An observational, descriptive, cross-sectional study. Study population From the population assigned to the participating healthcare centres, a cluster random sampling stratified by age and gender will be performed to obtain 500 participants aged between 35 and 75. Those who meet the inclusion criteria and give written informed consent will be included in the study. Measurements Main dependent variables: cf-PWV determined using the SphygmoCor System and CAVI estimated using VASERA. Secondary dependent variables: telomere length, carotid intima-media thickness, central and peripheral augmentation index, ankle-brachial pulse wave velocity, ankle-brachial index, retinal arteriovenous index, and renal and cardiac organ damage. Independent variables: lifestyles (physical activity, adherence to the Mediterranean diet, alcohol and tobacco consumption); psychological factors (depression, anxiety and chronic stress); inflammatory factors and oxidative stress. Ethics and dissemination The study has been approved by the clinical research ethics committee of the healthcare area of Salamanca. All study participants will sign an informed consent form agreeing to participate in the study in compliance with the Declaration of Helsinki and the WHO standards for observational studies. The results of this study will allow the understanding of the relationship of the different influencing factors and their relative weight in the development of EVA. At least 5 publications in first-quartile scientific journals are planned. Trial registration number NCT02623894; Pre

  9. Comparison of accelerated T1-weighted whole-brain structural-imaging protocols.

    PubMed

    Falkovskiy, Pavel; Brenner, Daniel; Feiweier, Thorsten; Kannengiesser, Stephan; Maréchal, Bénédicte; Kober, Tobias; Roche, Alexis; Thostenson, Kaely; Meuli, Reto; Reyes, Denise; Stoecker, Tony; Bernstein, Matt A; Thiran, Jean-Philippe; Krueger, Gunnar

    2016-01-01

    Imaging in neuroscience, clinical research and pharmaceutical trials often employs the 3D magnetisation-prepared rapid gradient-echo (MPRAGE) sequence to obtain structural T1-weighted images with high spatial resolution of the human brain. Typical research and clinical routine MPRAGE protocols with ~1mm isotropic resolution require data acquisition time in the range of 5-10min and often use only moderate two-fold acceleration factor for parallel imaging. Recent advances in MRI hardware and acquisition methodology promise improved leverage of the MR signal and more benign artefact properties in particular when employing increased acceleration factors in clinical routine and research. In this study, we examined four variants of a four-fold-accelerated MPRAGE protocol (2D-GRAPPA, CAIPIRINHA, CAIPIRINHA elliptical, and segmented MPRAGE) and compared clinical readings, basic image quality metrics (SNR, CNR), and automated brain tissue segmentation for morphological assessments of brain structures. The results were benchmarked against a widely-used two-fold-accelerated 3T ADNI MPRAGE protocol that served as reference in this study. 22 healthy subjects (age=20-44yrs.) were imaged with all MPRAGE variants in a single session. An experienced reader rated all images of clinically useful image quality. CAIPIRINHA MPRAGE scans were perceived on average to be of identical value for reading as the reference ADNI-2 protocol. SNR and CNR measurements exhibited the theoretically expected performance at the four-fold acceleration. The results of this study demonstrate that the four-fold accelerated protocols introduce systematic biases in the segmentation results of some brain structures compared to the reference ADNI-2 protocol. Furthermore, results suggest that the increased noise levels in the accelerated protocols play an important role in introducing these biases, at least under the present study conditions. PMID:26297848

  10. Cytomegalovirus infection accelerates epigenetic aging.

    PubMed

    Kananen, Laura; Nevalainen, Tapio; Jylhävä, Juulia; Marttila, Saara; Hervonen, Antti; Jylhä, Marja; Hurme, Mikko

    2015-12-01

    Epigenetic mechanisms such as DNA methylation (DNAm) have a central role in the regulation of gene expression and thereby in cellular differentiation and tissue homeostasis. It has recently been shown that aging is associated with profound changes in DNAm. Several of these methylation changes take place in a clock-like fashion, i.e. correlating with the calendar age of an individual. Thus, the epigenetic clock based on these kind of DNAm changes could provide a new biomarker for human aging process, i.e. being able to separate the calendar and biological age. Information about the correlation of the time indicated by this clock to the various aspects of immunosenescence is still missing. As chronic cytomegalovirus (CMV) infection is probably one of the major driving forces of immunosenescence, we now have analyzed the correlation of CMV seropositivity with the epigenetic age in the Vitality 90+cohort 1920 (122 nonagenarians and 21 young controls, CMV seropositivity rates 95% and 57%, respectively). The data showed that CMV seropositivity was associated with a higher epigenetic age in both of these age groups (median 26.5 vs. 24.0 (p < 0.02,Mann–Whitney U-test) in the young controls and 76.0 vs. 70.0 (p < 0.01) in the nonagenarians). Thus, these data provide a new aspect to the CMV associated pathological processes. PMID:26485162

  11. PETN Coarsening - Predictions from Accelerated Aging Data

    SciTech Connect

    Maiti, Amitesh; Gee, Richard H.

    2011-03-30

    Ensuring good ignition properties over long periods of time necessitates maintaining a good level of porosity in powders of initiator materials and preventing particle coarsening. To simulate porosity changes of such powder materials over long periods of time a common strategy is to perform accelerated aging experiments over shorter time spans at elevated temperatures. In this paper we examine historical accelerated-aging data on powders of Pentaerythritol Tetranitrate (PETN), an important energetic material, and make predictions for long-term aging under ambient conditions. Lastly, we develop an evaporation-condensation- based model to provide some mechanistic understanding of the coarsening process.

  12. Quantifying PV module microclimates and translation into accelerated weathering protocols

    NASA Astrophysics Data System (ADS)

    Phillips, Nancy H.; Scott, Kurt P.

    2014-10-01

    Long term reliability is not well addressed by current standards for PV modules or components, and developing accelerated weathering stress protocols to test the resistance of key components to wear-out is an active area of research. A first step is to understand and quantify the range of actual stresses modules will encounter in the various mounting configurations and in-service environments. In this paper, we use real-world data to benchmark PV module service environments in hot/dry, hot/wet, and temperate environments, with subsequent analysis to translate the microclimate data into a portfolio of practical weathering instrument settings.

  13. Accelerated epigenetic aging in Down syndrome

    PubMed Central

    Horvath, Steve; Garagnani, Paolo; Bacalini, Maria Giulia; Pirazzini, Chiara; Salvioli, Stefano; Gentilini, Davide; Di Blasio, Anna Maria; Giuliani, Cristina; Tung, Spencer; Vinters, Harry V; Franceschi, Claudio

    2015-01-01

    Down Syndrome (DS) entails an increased risk of many chronic diseases that are typically associated with older age. The clinical manifestations of accelerated aging suggest that trisomy 21 increases the biological age of tissues, but molecular evidence for this hypothesis has been sparse. Here, we utilize a quantitative molecular marker of aging (known as the epigenetic clock) to demonstrate that trisomy 21 significantly increases the age of blood and brain tissue (on average by 6.6 years, P = 7.0 × 10−14). PMID:25678027

  14. Accelerated epigenetic aging in Down syndrome.

    PubMed

    Horvath, Steve; Garagnani, Paolo; Bacalini, Maria Giulia; Pirazzini, Chiara; Salvioli, Stefano; Gentilini, Davide; Di Blasio, Anna Maria; Giuliani, Cristina; Tung, Spencer; Vinters, Harry V; Franceschi, Claudio

    2015-06-01

    Down Syndrome (DS) entails an increased risk of many chronic diseases that are typically associated with older age. The clinical manifestations of accelerated aging suggest that trisomy 21 increases the biological age of tissues, but molecular evidence for this hypothesis has been sparse. Here, we utilize a quantitative molecular marker of aging (known as the epigenetic clock) to demonstrate that trisomy 21 significantly increases the age of blood and brain tissue (on average by 6.6 years, P = 7.0 × 10(-14)). PMID:25678027

  15. Obesity accelerates epigenetic aging of human liver.

    PubMed

    Horvath, Steve; Erhart, Wiebke; Brosch, Mario; Ammerpohl, Ole; von Schönfels, Witigo; Ahrens, Markus; Heits, Nils; Bell, Jordana T; Tsai, Pei-Chien; Spector, Tim D; Deloukas, Panos; Siebert, Reiner; Sipos, Bence; Becker, Thomas; Röcken, Christoph; Schafmayer, Clemens; Hampe, Jochen

    2014-10-28

    Because of the dearth of biomarkers of aging, it has been difficult to test the hypothesis that obesity increases tissue age. Here we use a novel epigenetic biomarker of aging (referred to as an "epigenetic clock") to study the relationship between high body mass index (BMI) and the DNA methylation ages of human blood, liver, muscle, and adipose tissue. A significant correlation between BMI and epigenetic age acceleration could only be observed for liver (r = 0.42, P = 6.8 × 10(-4) in dataset 1 and r = 0.42, P = 1.2 × 10(-4) in dataset 2). On average, epigenetic age increased by 3.3 y for each 10 BMI units. The detected age acceleration in liver is not associated with the Nonalcoholic Fatty Liver Disease Activity Score or any of its component traits after adjustment for BMI. The 279 genes that are underexpressed in older liver samples are highly enriched (1.2 × 10(-9)) with nuclear mitochondrial genes that play a role in oxidative phosphorylation and electron transport. The epigenetic age acceleration, which is not reversible in the short term after rapid weight loss induced by bariatric surgery, may play a role in liver-related comorbidities of obesity, such as insulin resistance and liver cancer. PMID:25313081

  16. Can accelerated aqueous aging simulate in vivo oxidation of gamma-sterilized UHMWPE?

    PubMed

    Mazzucco, Daniel C; Dumbleton, John; Kurtz, Steven M

    2006-10-01

    Oxidation of ultrahigh molecular weight polyethylene (UHMWPE) gamma-sterilized arthroplasty components occurs in vivo. Though accelerated in vitro protocols have been developed to test the relative oxidation resistance of various types of UHMWPE, it is desirable to develop an accelerated aging protocol that more closely approximates the in vivo environment. The goal of this study was to investigate the effects of temperature, solute, and oxygen partial pressure in aqueous media on the oxidation of gamma-sterilized UHMWPE, as the basis for the development of improved accelerated aging protocols. The accelerated oxidation behavior of gamma-sterilized GUR 1150 was studied at 60 and 70 degrees C in an open vessel filled with distilled water or PBS in equilibrium with a controlled partial pressure of oxygen. The extent of oxidation was assessed using standardized mechanical and chemical evaluation techniques (small punch and Fourier transform infrared spectroscopy). Accelerated oxidation of UHMWPE was achieved in aqueous environments; however, both clinically relevant and nonrelevant oxidation species (e.g., aldehydes) were observed for long aging times at 60 degrees C, and for all aging times at 70 degrees C. These findings point the way to the development of an accelerated aging protocol. The current data, considered in conjunction with real-time aging studies, suggest that a temperature between body temperature and 60 degrees C may accelerate oxidative degradation without altering the oxidative patterns encountered in vivo.

  17. Accelerated aging test on LEDs life estimation

    NASA Astrophysics Data System (ADS)

    Dong, Yi; Zhang, Shu-sheng; Du, Jiang-qi

    2011-11-01

    Light-emitting diodes(LEDs) have become very attractive in different application field such as Solid State Lighting, automotive and street lights, due to their long operative lifetime, lower energy consumption etc. This paper mainly introduces the accelerated aging test, we focus our attention on the study of a life model for LEDs by relating the time to failure with the supplying condition. The constant accelerated aging experiments were firstly performed on LED samples. Process the experiment data by exploiting the degradation of LED optical power formula and degradation coefficient. Finally, the average lifetime of the samples under normal conditions was calculated via using numerical analytical method. According to data, analysis the test result and the failure mechanism of LED, provide the technical basis to improve product design and quality assurance.

  18. Insights into accelerated aging of SSL luminaires

    SciTech Connect

    Davis, J. Lynn; Lamvik, Michael; Bittle, James; Shepherd, Sarah; Yaga, Robert; Baldasaro, Nick; Solano, Eric; Bobashev, Georgiy

    2013-09-30

    Although solid-state lighting (SSL) products are often intended to have product lifetimes of 15 years or more, the rapid change in technology has created a need for accelerated life tests (ALTs) that can be performed in the span of several months. A critical element of interpreting results from any systems-level ALT is understanding of the impact of the test environment on each component. Because of its ubiquity in electronics, the use of temperature-humidity environments as potential ALTs for SSL luminaires was investigated. Results from testing of populations of three commercial 6” downlights in environments of 85oC and 85% relative humidity (RH) and 75oC and 75% RH are reported. These test environments were found to accelerate lumen depreciation of the entire luminaire optical system, including LEDs, lenses, and reflectors. The effects of aging were found to depend strongly on both the optical materials that were used and the design of the luminaire; this shows that the lumen maintenance behavior of SSL luminaires must be addressed at the optical systems level. Temperature-Humidity ALTs can be a useful test in understand lumainaire depreciation provided that proper consideration is given to the different aging rates of various materials. Since the impact of the temperature-humidity environment varies among components of the optical system, uniform aging of all system components in a single test is difficult to achieve.

  19. Insights into accelerated aging of SSL luminaires

    NASA Astrophysics Data System (ADS)

    Davis, J. Lynn; Lamvik, Michael; Bittle, James; Shepherd, Sarah; Yaga, Robert; Baldasaro, Nick; Solano, Eric; Bobashev, Georgiy

    2013-09-01

    Although solid-state lighting (SSL) products are often intended to have product lifetimes of 15 years or more, the rapid change in technology has created a need for accelerated life tests (ALTs) that can be performed in the span of several months. A critical element of interpreting results from any systems-level ALT is understanding of the impact of the test environment on each component. Because of its ubiquity in electronics, the use of temperature-humidity environments as potential ALTs for SSL luminaires was investigated. Results from testing of populations of three commercial 6" downlights in environments of 85°C and 85% relative humidity (RH) and 75°C and 75% RH are reported. These test environments were found to accelerate lumen depreciation of the entire luminaire optical system, including LEDs, lenses, and reflectors. The effects of aging were found to depend strongly on both the optical materials that were used and the design of the luminaire; this shows that the lumen maintenance behavior of SSL luminaires must be addressed at the optical systems level. Temperature-Humidity ALTs can be a useful test in understand lumainaire depreciation provided that proper consideration is given to the different aging rates of various materials. Since the impact of the temperature-humidity environment varies among components of the optical system, uniform aging of all system components in a single test is difficult to achieve.

  20. Insights into accelerated aging of SSL luminaires

    DOE PAGES

    Davis, J. Lynn; Lamvik, Michael; Bittle, James; Shepherd, Sarah; Yaga, Robert; Baldasaro, Nick; Solano, Eric; Bobashev, Georgiy

    2013-09-30

    Although solid-state lighting (SSL) products are often intended to have product lifetimes of 15 years or more, the rapid change in technology has created a need for accelerated life tests (ALTs) that can be performed in the span of several months. A critical element of interpreting results from any systems-level ALT is understanding of the impact of the test environment on each component. Because of its ubiquity in electronics, the use of temperature-humidity environments as potential ALTs for SSL luminaires was investigated. Results from testing of populations of three commercial 6” downlights in environments of 85oC and 85% relative humiditymore » (RH) and 75oC and 75% RH are reported. These test environments were found to accelerate lumen depreciation of the entire luminaire optical system, including LEDs, lenses, and reflectors. The effects of aging were found to depend strongly on both the optical materials that were used and the design of the luminaire; this shows that the lumen maintenance behavior of SSL luminaires must be addressed at the optical systems level. Temperature-Humidity ALTs can be a useful test in understand lumainaire depreciation provided that proper consideration is given to the different aging rates of various materials. Since the impact of the temperature-humidity environment varies among components of the optical system, uniform aging of all system components in a single test is difficult to achieve.« less

  1. Accelerated Aging in Electrolytic Capacitors for Prognostics

    NASA Technical Reports Server (NTRS)

    Celaya, Jose R.; Kulkarni, Chetan; Saha, Sankalita; Biswas, Gautam; Goebel, Kai Frank

    2012-01-01

    The focus of this work is the analysis of different degradation phenomena based on thermal overstress and electrical overstress accelerated aging systems and the use of accelerated aging techniques for prognostics algorithm development. Results on thermal overstress and electrical overstress experiments are presented. In addition, preliminary results toward the development of physics-based degradation models are presented focusing on the electrolyte evaporation failure mechanism. An empirical degradation model based on percentage capacitance loss under electrical overstress is presented and used in: (i) a Bayesian-based implementation of model-based prognostics using a discrete Kalman filter for health state estimation, and (ii) a dynamic system representation of the degradation model for forecasting and remaining useful life (RUL) estimation. A leave-one-out validation methodology is used to assess the validity of the methodology under the small sample size constrain. The results observed on the RUL estimation are consistent through the validation tests comparing relative accuracy and prediction error. It has been observed that the inaccuracy of the model to represent the change in degradation behavior observed at the end of the test data is consistent throughout the validation tests, indicating the need of a more detailed degradation model or the use of an algorithm that could estimate model parameters on-line. Based on the observed degradation process under different stress intensity with rest periods, the need for more sophisticated degradation models is further supported. The current degradation model does not represent the capacitance recovery over rest periods following an accelerated aging stress period.

  2. Accelerated Aging of Lead-Free Propellant

    NASA Technical Reports Server (NTRS)

    Furrow, Keith W.; Jervey, David D.

    2000-01-01

    Following higher than expected 2-NDPA depletion rates in a lead-free doublebase formulation (RPD-422), an accelerated aging study was conducted to verify the depletion rates. A test plan was prepared to compare the aging characteristics of lead-free propellant and NOSIH-AA2. The study was also designed to determine which lead-free ballistic modifiers accelerated 2-NDPA depletion. The increased depletion rate occurred in propellants containing monobasic copper salicylate. Four lead-free propellants were then formulated to improved aging characteristics over previous lead-free propellant formulations. The new formulations reduced or replaced the monobasic copper salicylate. The new formulations had improved aging characteristics. Their burn rates, however, were unacceptable for use in a 2.75 inch rocket. To compare aging characteristics, stabilizer depletion rates of RPD-422, AA2, M28, and RLC 470/6A were measured or taken from the literature. The data were fit to a kinetic model. The model contained first and zero order terms which allowed the stabilizer concentration to go to zero. In the model, only the concentration of the primary stabilizer was considered. Derivatives beyond the first nitrated or nitroso derivative of 2-NPDA were not considered. The rate constants were fit to the Arrhenius equation and extrapolated to lower temperatures. The time to complete stabilizer depletion was estimated using the kinetic model. The four propellants were compared and the RPD-422 depleted faster at 45 C than both A22 and M28. These types of predictions depend on the validity of the model and on confidence in the Arrhenius relationship holding at lower temperatures. At 45 C, the zero order portion of the model dominates the depletion rate.

  3. Accelerated aging of EPDM and butyl elastomers

    SciTech Connect

    Wilson, M.H.

    1996-06-01

    This study was composed of three parts: a post cure study to optimize final properties of an ethylene-propylene-diene (EPDM) formulation, an accelerated aging study to compare the stress relaxation behavior of a butyl and an EPDM elastomer under compression, and a cursory evaluation of a new 70 Shore A EPDM. The optimum postcure for the EPDM was found to be 2 to 4 hours at 182{degrees}C in a vacuum. The EPDM was also shown to have superior aging characteristics compared to the butyl and is recommended for use instead of the butyl material. The physical properties for new 70 Shore A EPDM are satisfactory, and the stress relaxation behavior was only slightly inferior to the other EPDM.

  4. Degradation mechanisms and accelerated aging test design

    SciTech Connect

    Clough, R L; Gillen, K T

    1985-01-01

    The fundamental mechanisms underlying the chemical degradation of polymers can change as a function of environmental stress level. When this occurs, it greatly complicates any attempt to use accelerated tests for predicting long-term material degradation behaviors. Understanding how degradation mechanisms can change at different stress levels facilitates both the design and the interpretation of aging tests. Oxidative degradation is a predominant mechanism for many polymers exposed to a variety of different environments in the presence of air, and there are two mechanistic considerations which are widely applicable to material oxidation. One involves a physical process, oxygen diffusion, as a rate-limiting step. This mechanism can predominate at high stress levels. The second is a chemical process, the time-dependent decomposition of peroxide species. This leads to chain branching and can become a rate-controlling factor at lower stress levels involving time-scales applicable to use environments. The authors describe methods for identifying the operation of these mechanisms and illustrate the dramatic influence they can have on the degradation behaviors of a number of polymer types. Several commonly used approaches to accelerated aging tests are discussed in light of the behaviors which result from changes in degradation mechanisms. 9 references, 4 figures.

  5. Deactivation of Accelerated Engine-Aged and Field-Aged Fe-Zeolite SCR Catalysts

    SciTech Connect

    Toops, Todd J; Nguyen, Ke; Foster, Adam; Bunting, Bruce G; Hagaman, Edward {Ed} W; Jiao, Jian

    2010-01-01

    A single-cylinder diesel engine with an emissions control system - diesel oxidation catalyst (DOC), Fe-zeolite selective catalytic reduction (SCR) catalyst, and diesel particulate filter (DPF) - was used to perform accelerated thermal aging of the SCR catalyst. Cyclic aging is performed at SCR inlet temperatures of 650, 750 and 850 degrees C for up to 50 aging cycles. To assess the validity of the implemented accelerated thermal aging protocol, a field-aged SCR catalyst of similar formulation was also evaluated. The monoliths were cut into sections and evaluated for NO{sub x} performance in a bench-flow reactor. While the rear section of both the field-aged and the accelerated engine-aged SCR catalysts maintained high NO{sub x}conversion, 75-80% at 400 degrees C, the front section exhibited a drastic decrease to only 20-35% at 400 degrees C. This two-tiered deactivation was also observed for field-aged samples that were analyzed in this study. To understand the observed performance changes, thorough materials characterization was performed which revealed two primary degradation mechanisms. The first mechanism is a general Fe-zeolite deterioration which led to surface area losses, dealumination of the zeolite, and Fe{sub 2}O{sub 3} crystal growth. This degradation accelerated above 750 degrees C, and the effects were generally more severe in the front of the catalyst. The second deactivation mechanism is linked to trace levels of Pt that are suspected to be volatizing from the DOC and depositing on the front section of the SCR catalyst. Chemical evidence of this can be seen in the high levels of NH{sub 3} oxidation (80% conversion at 400 degrees C), which coincides with the decrease in performance.

  6. A Protocol for Aging Anurans Using Skeletochronology

    USGS Publications Warehouse

    McCreary, Brome; Pearl, Christopher A.; Adams, Michael J.

    2008-01-01

    Age distribution information can be an important part of understanding the biology of any population. Age estimates collected from the annual growth rings found in tooth and bone cross sections, often referred to as Lines of Arrested Growth (LAGs), have been used in the study of various animals. In this manual, we describe in detail all necessary steps required to obtain estimates of age from anuran bone cross sections via skeletochronological assessment. We include comprehensive descriptions of how to fix and decalcify toe specimens (phalanges), process a phalange prior to embedding, embed the phalange in paraffin, section the phalange using a microtome, stain and mount the cross sections of the phalange and read the LAGs to obtain age estimates.

  7. US Particle Accelerators at Age 50.

    ERIC Educational Resources Information Center

    Wilson, R. R.

    1981-01-01

    Reviews the development of accelerators over the past 50 years. Topics include: types of accelerators, including cyclotrons; sociology of accelerators (motivation, financing, construction, and use); impact of war; national laboratories; funding; applications; future projects; foreign projects; and international collaborations. (JN)

  8. Premature and accelerated aging: HIV or HAART?

    PubMed

    Smith, Reuben L; de Boer, Richard; Brul, Stanley; Budovskaya, Yelena; van Spek, Hans

    2012-01-01

    Highly active antiretroviral therapy (HAART) has significantly increased life expectancy of the human immunodeficiency virus (HIV)-positive population. Nevertheless, the average lifespan of HIV-patients remains shorter compared to uninfected individuals. Immunosenescence, a current explanation for this difference invokes heavily on viral stimulus despite HAART efficiency in viral suppression. We propose here that the premature and accelerated aging of HIV-patients can also be caused by adverse effects of antiretroviral drugs, specifically those that affect the mitochondria. The nucleoside reverse transcriptase inhibitor (NRTI) antiretroviral drug class for instance, is known to cause depletion of mitochondrial DNA via inhibition of the mitochondrial specific DNA polymerase-γ. Besides NRTIs, other antiretroviral drug classes such as protease inhibitors also cause severe mitochondrial damage by increasing oxidative stress and diminishing mitochondrial function. We also discuss important areas for future research and argue in favor of the use of Caenorhabditis elegans as a novel model system for studying these effects.

  9. Accelerated aging of polymer composite bridge materials

    NASA Astrophysics Data System (ADS)

    Carlson, Nancy M.; Blackwood, Larry G.; Torres, Lucinda L.; Rodriguez, Julio G.; Yoder, Timothy S.

    1999-05-01

    Accelerated aging research on samples of composite materials and candidate UV protective coatings is determining the effects of six environmental factors on material durability. Candidate fastener materials are being evaluated to determine corrosion rates and crevice corrosion effects at load-bearing joints. This work supports field testing of a 30-ft long, 18-ft wide polymer matrix composite (PMC) bridge at the Idaho National Engineering and Environmental Laboratory. Durability results and sensor data form test with live loads provide information required for determining the cost/benefit measures to use in life-cycle planning, determining a maintenance strategy, establishing applicable inspection techniques, and establishing guidelines, standards and acceptance criteria for PMC bridges for use in the transportation infrastructure.

  10. Accelerated Aging of Polymer Composite Bridge Materials

    SciTech Connect

    Carlson, Nancy Margaret; Blackwood, Larry Gene; Torres, Lucinda Laine; Rodriguez, Julio Gallardo; Yoder, Timothy Scott

    1999-03-01

    Accelerated aging research on samples of composite material and candidate ultraviolet (UV) protective coatings is determining the effects of six environmental factors on material durability. Candidate fastener materials are being evaluated to determine corrosion rates and crevice corrosion effects at load-bearing joints. This work supports field testing of a 30-ft long, 18-ft wide polymer matrix composite (PMC) bridge at the Idaho National Engineering and Environmental Laboratory (INEEL). Durability results and sensor data from tests with live loads provide information required for determining the cost/benefit measures to use in life-cycle planning, determining a maintenance strategy, establishing applicable inspection techniques, and establishing guidelines, standards, and acceptance criteria for PMC bridges for use in the transportation infrastructure.

  11. Accelerated aging syndromes, are they relevant to normal human aging?

    PubMed

    Dreesen, Oliver; Stewart, Colin L

    2011-09-01

    Hutchinson-Gilford Progeria (HGPS) and Werner syndromes are diseases that clinically resemble some aspects of accelerated aging. HGPS is caused by mutations in theLMNA gene resulting in post-translational processing defects that trigger Progeria in children. Werner syndrome, arising from mutations in the WRN helicase gene, causes premature aging in young adults. What are the molecular mechanism(s) underlying these disorders and what aspects of the diseases resemble physiological human aging? Much of what we know stems from the study of patient derived fibroblasts with both mutations resulting in increased DNA damage, primarily at telomeres. However, in vivo patients with Werner's develop arteriosclerosis, among other pathologies. In HGPS patients, including iPS derived cells from HGPS patients, as well as some mouse models for Progeria, vascular smooth muscle (VSM) appears to be among the most severely affected tissues. Defective Lamin processing, associated with DNA damage, is present in VSM from old individuals, indicating processing defects may be a factor in normal aging. Whether persistent DNA damage, particularly at telomeres, is the root cause for these pathologies remains to be established, since not all progeroid Lmna mutations result in DNA damage and genome instability.

  12. Acceleration of the aging process by oxygen

    NASA Technical Reports Server (NTRS)

    Miquel, J.; Lunderen, P. R.; Bensch, K. G.

    1975-01-01

    Tissue changes induced by hyperoxia have been compared with those of normal aging. Results of investigations using male flies prompt conclusion that normal aging, radiation syndrome, and hyperoxic injury share at least one common feature--lipid peroxidation damage to all mambranes resulting in accumulation of age pigment.

  13. Accelerated Aging of the M119 Simulator

    NASA Technical Reports Server (NTRS)

    Bixon, Eric R.

    2000-01-01

    This paper addresses the storage requirement, shelf life, and the reliability of M119 Whistling Simulator. Experimental conditions have been determined and the data analysis has been completed for the accelerated testing of the system. A general methodology to evaluate the shelf life of the system as a function of the storage time, temperature, and relative humidity is discussed.

  14. An Epigenetic Clock Measures Accelerated Aging in Treated HIV Infection.

    PubMed

    Boulias, Konstantinos; Lieberman, Judy; Greer, Eric Lieberman

    2016-04-21

    In this issue of Molecular Cell, Gross et al. (2016) find a CpG DNA methylation signature in blood cells of patients with chronic well-controlled HIV infection that correlates with accelerated aging. PMID:27105110

  15. Pathology of Mouse Models of Accelerated Aging.

    PubMed

    Harkema, L; Youssef, S A; de Bruin, A

    2016-03-01

    Progeroid mouse models display phenotypes in multiple organ systems that suggest premature aging and resemble features of natural aging of both mice and humans. The prospect of a significant increase in the global elderly population within the next decades has led to the emergence of "geroscience," which aims at elucidating the molecular mechanisms involved in aging. Progeroid mouse models are frequently used in geroscience as they provide insight into the molecular mechanisms that are involved in the highly complex process of natural aging. This review provides an overview of the most commonly reported nonneoplastic macroscopic and microscopic pathologic findings in progeroid mouse models (eg, osteoporosis, osteoarthritis, degenerative joint disease, intervertebral disc degeneration, kyphosis, sarcopenia, cutaneous atrophy, wound healing, hair loss, alopecia, lymphoid atrophy, cataract, corneal endothelial dystrophy, retinal degenerative diseases, and vascular remodeling). Furthermore, several shortcomings in pathologic analysis and descriptions of these models are discussed. Progeroid mouse models are valuable models for aging, but thorough knowledge of both the mouse strain background and the progeria-related phenotype is required to guide interpretation and translation of the pathology data. PMID:26864891

  16. Interlaboratory reproducibility of standard accelerated aging methods for oxidation of UHMWPE.

    PubMed

    Kurtz, S M; Muratoglu, O K; Buchanan, F; Currier, B; Gsell, R; Greer, K; Gualtieri, G; Johnson, R; Schaffner, S; Sevo, K; Spiegelberg, S; Shen, F W; Yau, S S

    2001-07-01

    During accelerating aging, experimental uncertainty may arise due to variability in the oxidation process, or due to limitations in the technique that is ultimately used to measure oxidation. The purpose of the present interlaboratory study was to quantify the repeatability and reproducibility of standard accelerated aging methods for ultra-high molecular weight polyethylene (UHMWPE). Sections (200 microm thick) were microtomed from the center of an extruded rod of GUR 4150 HP, gamma irradiated in air or nitrogen, and circulated to 12 institutions in the United States and Europe for characterization of oxidation before and after accelerated aging. Specimens were aged for 3 weeks at 80 degrees C in an air circulating oven or for 2 weeks at 70 degrees C in an oxygen bomb (maintained at 503 kPa (5 atm.) of O2) in accordance with the two standard protocols described in ASTM F 2003-00. FTIR spectra were collected from each specimen within 24 h of the start and finish of accelerated aging, and oxidation indices were calculated by normalizing the peak area of the carbonyl region by the reference peak areas at 1370 or 2022 cm(-1). The mean relative interlaboratory uncertainty of the oxidation data was 78.5% after oven aging and 129.1% after bomb aging. The oxidation index measurement technique was not found to be a significant factor in the reproducibility. Comparable relative intrainstitutional uncertainty was observed after oven aging and bomb aging. For both aging methods, institutions successfully discriminated between air-irradiated and control specimens. However, the large interinstitutional variation suggests that absolute performance standards for the oxidation index of UHMWPE after accelerated aging may not be practical at the present time.

  17. Accelerated Aging with Electrical Overstress and Prognostics for Power MOSFETs

    NASA Technical Reports Server (NTRS)

    Saha, Sankalita; Celaya, Jose Ramon; Vashchenko, Vladislav; Mahiuddin, Shompa; Goebel, Kai F.

    2011-01-01

    Power electronics play an increasingly important role in energy applications as part of their power converter circuits. Understanding the behavior of these devices, especially their failure modes as they age with nominal usage or sudden fault development is critical in ensuring efficiency. In this paper, a prognostics based health management of power MOSFETs undergoing accelerated aging through electrical overstress at the gate area is presented. Details of the accelerated aging methodology, modeling of the degradation process of the device and prognostics algorithm for prediction of the future state of health of the device are presented. Experiments with multiple devices demonstrate the performance of the model and the prognostics algorithm as well as the scope of application. Index Terms Power MOSFET, accelerated aging, prognostics

  18. Degradation of mechanical behavior in UHMWPE after natural and accelerated aging.

    PubMed

    Edidin, A A; Jewett, C W; Kalinowski, A; Kwarteng, K; Kurtz, S M

    2000-07-01

    Ultra-high molecular weight polyethylene (UHMWPE) is known to degrade during natural (shelf) aging following gamma irradiation in air, but the mechanical signature of degradation remains poorly understood. Accelerated aging methods have been developed to reproduce the natural aging process as well as to precondition total joint replacement components prior to joint simulator wear testing. In this study, we compared the mechanical behavior of naturally (shelf) aged and accelerated aged tibial inserts using a previously validated miniature specimen testing technique known as the small punch test. Tibial inserts made-of GUR 1120 and sterilized with 25 to 40 kGy of gamma radiation (in air) in 1988, 1993, and 1997 were obtained; a subset of the 1997 implants were subjected to 4 weeks of accelerated aging in air at 80 degrees C. To determine the spatial variation of mechanical properties within each insert, miniature disk shaped specimens were machined from the surface and subsurface regions of the inserts. Analysis of variance of the test data showed that aging significantly affected the small punch test measures of elastic modulus, initial load, ultimate load, ultimate displacement, and work to failure. The accelerated aging protocol was unable to reproduce the spatial mechanical profile seen in shelf aged components, but it did mechanically degrade the surface of GUR 1120 tibial components to an extent comparable to that seen after 10 years of natural aging. Test specimens showed a fracture morphology consistent with the decreased ductility and toughness which was corroborated by the small punch test metrics of this study. Our data support the hypothesis that UHMWPE undergoes a spatially nonuniform change towards a less ductile (more brittle) mechanical behavior after gamma irradiation in air and shelf aging.

  19. Accelerated thermal and radiative ageing of hydrogenated NBR for DRC

    SciTech Connect

    Mares, G.; Notingher, P.

    1996-12-31

    The accelerated thermal and gamma radiation ageing of HNBR carbon black-T80 has been studied by measuring the residual deformation under constant deflection -- DRC, in air, using a relevant equation for the relaxation phenomena. The residual deformation under constant deflection during the process of accelerated ageing is increasing but the structure of polymer answers in the proper manner to the mechanical stress. The degradation equations were obtained, using Alfrey model for the relaxation polymer subject to compression and an Arrhenius dependence for the chemical reaction rate. The inverted relaxation time for the thermal degradation is depending on the chemical reaction rate and the dose rate of gamma radiation.

  20. HEART Pathway Accelerated Diagnostic Protocol Implementation: Prospective Pre-Post Interrupted Time Series Design and Methods

    PubMed Central

    Wells, Brian J

    2016-01-01

    Background Most patients presenting to US Emergency Departments (ED) with chest pain are hospitalized for comprehensive testing. These evaluations cost the US health system >$10 billion annually, but have a diagnostic yield for acute coronary syndrome (ACS) of <10%. The history/ECG/age/risk factors/troponin (HEART) Pathway is an accelerated diagnostic protocol (ADP), designed to improve care for patients with acute chest pain by identifying patients for early ED discharge. Prior efficacy studies demonstrate that the HEART Pathway safely reduces cardiac testing, while maintaining an acceptably low adverse event rate. Objective The purpose of this study is to determine the effectiveness of HEART Pathway ADP implementation within a health system. Methods This controlled before-after study will accrue adult patients with acute chest pain, but without ST-segment elevation myocardial infarction on electrocardiogram for two years and is expected to include approximately 10,000 patients. Outcomes measures include hospitalization rate, objective cardiac testing rates (stress testing and angiography), length of stay, and rates of recurrent cardiac care for participants. Results In pilot data, the HEART Pathway decreased hospitalizations by 21%, decreased hospital length (median of 12 hour reduction), without increasing adverse events or recurrent care. At the writing of this paper, data has been collected on >5000 patient encounters. The HEART Pathway has been fully integrated into health system electronic medical records, providing real-time decision support to our providers. Conclusions We hypothesize that the HEART Pathway will safely reduce healthcare utilization. This study could provide a model for delivering high-value care to the 8-10 million US ED patients with acute chest pain each year. ClinicalTrial Clinicaltrials.gov NCT02056964; https://clinicaltrials.gov/ct2/show/NCT02056964 (Archived by WebCite at http://www.webcitation.org/6ccajsgyu) PMID:26800789

  1. Development of an Accelerated Weathering Protocol using Weatherometers for Reliability Study of Mini-Modules and Encapsulation Materials

    SciTech Connect

    Pern, F. J.

    2000-01-01

    This paper describes the needs, reasoning, approaches, and technical details to establish a practical accelerated weathering test (AWT) protocol for indoor testing of the photothermal stability of encapsulation materials and encapsulated solar cells and minimodules.

  2. Accelerated aging of GaAs concentrator solar cells

    SciTech Connect

    Gregory, P.E.

    1982-04-01

    An accelerated aging study of AlGaAs/GaAs solar cells has been completed. The purpose of the study was to identify the possible degradation mechanisms of AlGaAs/GaAs solar cells in terrestrial applications. Thermal storage tests and accelerated AlGaAs corrosion studies were performed to provide an experimental basis for a statistical analysis of the estimated lifetime. Results of this study suggest that a properly designed and fabricated AlGaAs/GaAs solar cell can be mechanically rugged and environmentally stable with projected lifetimes exceeding 100 years.

  3. Cognitive deterioration in adult epilepsy: Does accelerated cognitive ageing exist?

    PubMed

    Breuer, L E M; Boon, P; Bergmans, J W M; Mess, W H; Besseling, R M H; de Louw, A; Tijhuis, A G; Zinger, S; Bernas, A; Klooster, D C W; Aldenkamp, A P

    2016-05-01

    A long-standing concern has been whether epilepsy contributes to cognitive decline or so-called 'epileptic dementia'. Although global cognitive decline is generally reported in the context of chronic refractory epilepsy, it is largely unknown what percentage of patients is at risk for decline. This review is focused on the identification of risk factors and characterization of aberrant cognitive trajectories in epilepsy. Evidence is found that the cognitive trajectory of patients with epilepsy over time differs from processes of cognitive ageing in healthy people, especially in adulthood-onset epilepsy. Cognitive deterioration in these patients seems to develop in a 'second hit model' and occurs when epilepsy hits on a brain that is already vulnerable or vice versa when comorbid problems develop in a person with epilepsy. Processes of ageing may be accelerated due to loss of brain plasticity and cognitive reserve capacity for which we coin the term 'accelerated cognitive ageing'. We believe that the concept of accelerated cognitive ageing can be helpful in providing a framework understanding global cognitive deterioration in epilepsy.

  4. Cognitive deterioration in adult epilepsy: Does accelerated cognitive ageing exist?

    PubMed

    Breuer, L E M; Boon, P; Bergmans, J W M; Mess, W H; Besseling, R M H; de Louw, A; Tijhuis, A G; Zinger, S; Bernas, A; Klooster, D C W; Aldenkamp, A P

    2016-05-01

    A long-standing concern has been whether epilepsy contributes to cognitive decline or so-called 'epileptic dementia'. Although global cognitive decline is generally reported in the context of chronic refractory epilepsy, it is largely unknown what percentage of patients is at risk for decline. This review is focused on the identification of risk factors and characterization of aberrant cognitive trajectories in epilepsy. Evidence is found that the cognitive trajectory of patients with epilepsy over time differs from processes of cognitive ageing in healthy people, especially in adulthood-onset epilepsy. Cognitive deterioration in these patients seems to develop in a 'second hit model' and occurs when epilepsy hits on a brain that is already vulnerable or vice versa when comorbid problems develop in a person with epilepsy. Processes of ageing may be accelerated due to loss of brain plasticity and cognitive reserve capacity for which we coin the term 'accelerated cognitive ageing'. We believe that the concept of accelerated cognitive ageing can be helpful in providing a framework understanding global cognitive deterioration in epilepsy. PMID:26900650

  5. Accelerated aging test results for aerospace wire insulation constructions

    NASA Technical Reports Server (NTRS)

    Dunbar, William G.

    1995-01-01

    Several wire insulation constructions were evaluated with and without continuous glow discharges at low pressure and high temperature to determine the aging characteristics of acceptable wire insulation constructions. It was known at the beginning of the test program that insulation aging takes several years when operated at normal ambient temperature and pressure of 20 C and 760 torr. Likewise, it was known that the accelerated aging process decreases insulation life by approximately 50% for each 10 C temperature rise. Therefore, the first phases of the program, not reported in these test results, were to select wire insulation constructions that could operate at high temperature and low pressure for over 10,000 hours with negligible shrinkage and little materials' deterioration.The final phase of the program was to determine accelerated aging characteristics. When an insulation construction is subjected to partial discharges the insulation is locally heated by the bombardment of the discharges, the insulation is also subjected to ozone and other deteriorating gas particles that may significantly increase the aging process. Several insulation systems using either a single material or combinations of teflon, kapton, and glass insulation constructions were tested. All constructions were rated to be partial discharge and/or corona-free at 240 volts, 400 Hz and 260 C (500 F) for 50, 000 hours at altitudes equivalent to the Paschen law. Minimum partial discharge aging tests were preceded by screening tests lasting 20 hours at 260 C. The aging process was accelerated by subjecting the test articles to temperatures up to 370 C (700 F) with and without partial discharges. After one month operation with continuous glow discharges surrounding the test articles, most insulation systems were either destroyed or became brittle, cracked, and unsafe for use. Time with space radiation as with partial discharges is accumulative.

  6. Accelerated aging and stabilization of radiation-vulcanized EPDM rubber

    NASA Astrophysics Data System (ADS)

    Basfar, A. A.; Abdel-Aziz, M. M.; Mofti, S.

    2000-03-01

    The effect of different antioxidants and their mixtures on the thermal aging and accelerated weathering of γ-radiation vulcanized EPDM rubber in presence of crosslinking coagent, was investigated. The compounds used were either a synergistic blend of phenolic and phosphite antioxidants, i.e. 1:4 Irganox 1076: Irgafos 168 or a blend of arylamine and quinoline type antioxidants, i.e. 1:1 IPPD: TMQ, at fixed concentration. Tinuvin 622 LD hindered amine light stabilized (HALS) was also used. The response was evaluated by the tensile strength and elongation at break for irradiated samples after thermal aging at 100°C for 28 days and accelerated weathering (Xenon test) up to 200 h.

  7. Accelerated optical polymer aging studies for LED luminaire applications

    NASA Astrophysics Data System (ADS)

    Estupiñán, Edgar; Wendling, Peter; Kostrun, Marijan; Garner, Richard

    2013-09-01

    There is a need in the lighting industry to design and implement accelerated aging methods that accurately simulate the aging process of LED luminaire components. In response to this need, we have built a flexible and reliable system to study the aging characteristics of optical polymer materials, and we have employed it to study a commercially available LED luminaire diffuser made of PMMA. The experimental system consists of a "Blue LED Emitter" and a working surface. Both the temperatures of the samples and the optical powers of the LEDs are appropriately characterized in the system. Several accelerated aging experiments are carried out at different temperatures and optical powers over a 90 hour period and the measured transmission values are used as inputs to a degradation model derived using plausibility arguments. This model seems capable of predicting the behavior of the material as a function of time, temperature and optical power. The model satisfactorily predicts the measured transmission values of diffusers aged in luminaires at two different times and thus can be used to make application recommendations for this material. Specifically, at 35000 hours (the manufacturer's stated life of the luminaire) and at the typical operational temperature of the diffuser, the model predicts a transmission loss of only a few percent over the original transmission of the material at 450 nm, which renders this material suitable for this application.

  8. Tracking accelerated aging of composites with ultrasonic attenuation measurements

    SciTech Connect

    Chinn, D.J.; Durbin, P.F.; Thomas, G.H.; Groves, S.E.

    1996-10-01

    Composite materials are steadily replacing traditional materials in many industries. For many carbon composite materials, particularly in aerospace applications, durability is a critical design parameter which must be accurately characterized. Lawrence Livermore National Laboratory (LLNL) and Boeing Commercial Airplane Group have established a cooperative research and development agreement (CRADA) to assist in the high speed research program at Boeing. LLNL`s expertise in fiber composites, computer modeling, mechanical testing, chemical analysis and nondestructive evaluation (ND) will contribute to the study of advanced composite materials in commercial aerospace applications. Through thermo-mechanical experiments with periodic chemical analysis and nondestructive evaluation, the aging mechanisms in several continuous fiber polymer composites will be studied. Several measurement techniques are being studied for their correlation with aging. This paper describes through-transmission ultrasonic attenuation measurements of isothermally aged composite materials and their use as a tracking parameter for accelerated aging.

  9. A practical protocol to accelerate the breeding process of rice in semitropical and tropical regions

    PubMed Central

    Li, Jun; Hou, Xianhui; Liu, Jindi; Qian, Changgen; Gao, Rongcun; Li, Linchuan; Li, Jinjun

    2015-01-01

    Breeding of excellent rice varieties is essential for modern rice production. Typical breeding procedures to introduce and maintain valuable agricultural traits require at least 8 generations from crossing to stabilization, always taking more than 4–5 years of work. This long and tedious process is the rate-limiting step in the development of new varieties, and therefore fast culturing methods are in urgent need. Taking advantage of early flowering characteristics of light-sensitive rice under short-day conditions, we have developed a practical protocol to accelerate the breeding cycle of rice, which we have termed the “1 + 2”, “2 + 2”, “1 + 3”, and “0 + 5” methods according to the different rice varieties and different breeding purposes. We have also incorporated several techniques, including glume cutting, seed desiccation at 50°C in a drier seed dormancy breakage with low concentration of HNO3, and direct seeding. Using the above strategy, we have shortened the life cycle of light-sensitive rice varieties to about 70 days, making it possible for several rice cultivars to proliferate 4–5 generations in a single calendar year. This protocol greatly accelerates the process of new variety breeding, and can be used in rice research for shortening the process of genetic analysis and the construction of mapping populations. PMID:26175620

  10. Electrochemical migration technique to accelerate ageing of cementitious materials

    NASA Astrophysics Data System (ADS)

    Babaahmadi, A.; Tang, L.; Abbas, Z.

    2013-07-01

    Durability assessment of concrete structures for constructions in nuclear waste repositories requires long term service life predictions. As deposition of low and intermediate level radioactive waste (LILW) takes up to 100 000 years, it is necessary to analyze the service life of cementitious materials in this time perspective. Using acceleration methods producing aged specimens would decrease the need of extrapolating short term data sets. Laboratory methods are therefore, needed for accelerating the ageing process without making any influencing distortion in the properties of the materials. This paper presents an electro-chemical migration method to increase the rate of calcium leaching from cementitious specimens. This method is developed based on the fact that major long term deterioration process of hardened cement paste in concrete structures for deposition of LILW is due to slow diffusion of calcium ions. In this method the cementitious specimen is placed in an electrochemical cell as a porous path way through which ions can migrate at a rate far higher than diffusion process. The electrical field is applied to the cell in a way to accelerate the ion migration without making destructions in the specimen's micro and macroscopic properties. The anolyte and catholyte solutions are designed favoring dissolution of calcium hydroxide and compensating for the leached calcium ions with another ion like lithium.

  11. Accelerated aging tests of liners for uranium mill tailings disposal

    SciTech Connect

    Barnes, S.M.; Buelt, J.L.; Hale, V.Q.

    1981-11-01

    This document describes the results of accelerated aging tests to determine the long-term effectiveness of selected impoundment liner materials in a uranium mill tailings environment. The study was sponsored by the US Department of Energy under the Uranium Mill Tailings Remedial Action Project. The study was designed to evaluate the need for, and the performance of, several candidate liners for isolating mill tailings leachate in conformance with proposed Environmental Protection Agency and Nuclear Regulatory Commission requirements. The liners were subjected to conditions known to accelerate the degradation mechanisms of the various liners. Also, a test environment was maintained that modeled the expected conditions at a mill tailings impoundment, including ground subsidence and the weight loading of tailings on the liners. A comparison of installation costs was also performed for the candidate liners. The laboratory testing and cost information prompted the selection of a catalytic airblown asphalt membrane and a sodium bentonite-amended soil for fiscal year 1981 field testing.

  12. Infection susceptibility and immune senescence with advancing age replicated in accelerated aging Lmna(Dhe) mice.

    PubMed

    Xin, Lijun; Jiang, Tony T; Kinder, Jeremy M; Ertelt, James M; Way, Sing Sing

    2015-12-01

    Aging confers increased susceptibility to common pathogens including influenza A virus. Despite shared vulnerability to infection with advancing age in humans and rodents, the relatively long time required for immune senescence to take hold practically restricts the use of naturally aged mice to investigate aging-induced immunological shifts. Here, we show accelerated aging Lmna(Dhe) mice with spontaneous mutation in the nuclear scaffolding protein, lamin A, replicate infection susceptibility, and substantial immune cell shifts that occur with advancing age. Naturally aged (≥ 20 month) and 2- to 3-month-old Lmna(Dhe) mice share near identically increased influenza A susceptibility compared with age-matched Lmna(WT) control mice. Increased mortality and higher viral burden after influenza infection in Lmna(Dhe) mice parallel reduced accumulation of lung alveolar macrophage cells, systemic expansion of immune suppressive Foxp3⁺ regulatory T cells, and skewed immune dominance among viral-specific CD8⁺T cells similar to the immunological phenotype of naturally aged mice. Thus, aging-induced infection susceptibility and immune senescence are replicated in accelerated aging Lmna(Dhe) mice. PMID:26248606

  13. Basal-Bolus Insulin Protocols Enter the Computer Age

    PubMed Central

    Wei, Nancy J.; Wexler, Deborah J.

    2011-01-01

    Diabetes affects approximately one quarter of all hospitalized patients. Poor inpatient glycemic control has been associated with increased risk for multiple adverse events including surgical site infections, prolonged hospital length of stay, and mortality. Inpatient glycemic control protocols based on physiologic basal-bolus insulin regimens have been shown to improve glycemia and clinical outcomes and are recommended by the American Diabetes Association, the American Association of Clinical Endocrinologists, and the Society of Hospital Medicine for inpatient glycemic management of noncritically ill patients. The 2009 Health Information Technology for Economic and Clinical Health (HITECH) Act will catalyze widespread computerized medication order entry implementation over the next few years. Here, we focus on the noncritical care setting and review the background on inpatient glycemic management as it pertains to computerized order entry, the translation and efficacy of computerizing glycemic control protocols, and the barriers to computerizing glycemic protocols. PMID:22015856

  14. Accelerated Aging Experiments for Capacitor Health Monitoring and Prognostics

    NASA Technical Reports Server (NTRS)

    Kulkarni, Chetan S.; Celaya, Jose Ramon; Biswas, Gautam; Goebel, Kai

    2012-01-01

    This paper discusses experimental setups for health monitoring and prognostics of electrolytic capacitors under nominal operation and accelerated aging conditions. Electrolytic capacitors have higher failure rates than other components in electronic systems like power drives, power converters etc. Our current work focuses on developing first-principles-based degradation models for electrolytic capacitors under varying electrical and thermal stress conditions. Prognostics and health management for electronic systems aims to predict the onset of faults, study causes for system degradation, and accurately compute remaining useful life. Accelerated life test methods are often used in prognostics research as a way to model multiple causes and assess the effects of the degradation process through time. It also allows for the identification and study of different failure mechanisms and their relationships under different operating conditions. Experiments are designed for aging of the capacitors such that the degradation pattern induced by the aging can be monitored and analyzed. Experimental setups and data collection methods are presented to demonstrate this approach.

  15. Cerebrolysin Accelerates Metamorphosis and Attenuates Aging-Accelerating Effect of High Temperature in Drosophila Melanogaster

    PubMed Central

    Navrotskaya, V.; Vorobyova, L.; Sharma, H.; Muresanu, D.; Summergrad, P.

    2015-01-01

    Cerebrolysin® (CBL) is a neuroprotective drug used for the treatment of neurodegenerative diseases. CBL’s mechanisms of action remain unclear. Involvement of tryptophan (TRP)–kynurenine (KYN) pathway in neuroprotective effect of CBL might be suggested considering that modulation of KYN pathway of TRP metabolism by CBL, and protection against eclosion defect and prolongation of life span of Drosophila melanogaster with pharmacologically or genetically-induced down-regulation of TRP conversion into KYN. To investigate possible involvement of TRP–KYN pathway in mechanisms of neuroprotective effect of CBL, we evaluated CBL effects on metamorphosis and life span of Drosophila melanogaster maintained at 23 °C and 28 °C ambient temperature. CBL accelerated metamorphosis, exerted strong tendency (p = 0.04) to prolong life span in female but not in male flies, and attenuated aging-accelerating effect of high (28 °C) ambient temperature in both female and male flies. Further research of CBL effects on metamorphosis and resistance to aging-accelerating effect of high temperature might offer new insights in mechanisms of its neuroprotective action and expand its clinical applications. PMID:25798213

  16. Accelerated ageing: from mechanism to therapy through animal models.

    PubMed

    Osorio, Fernando G; Obaya, Alvaro J; López-Otín, Carlos; Freije, José M P

    2009-02-01

    Ageing research benefits from the study of accelerated ageing syndromes such as Hutchinson-Gilford progeria syndrome (HGPS), characterized by the early appearance of symptoms normally associated with advanced age. Most HGPS cases are caused by a mutation in the gene LMNA, which leads to the synthesis of a truncated precursor of lamin A known as progerin that lacks the target sequence for the metallopotease FACE-1/ZMPSTE24 and remains constitutively farnesylated. The use of Face-1/Zmpste24-deficient mice allowed us to demonstrate that accumulation of farnesylated prelamin A causes severe abnormalities of the nuclear envelope, hyper-activation of p53 signalling, cellular senescence, stem cell dysfunction and the development of a progeroid phenotype. The reduction of prenylated prelamin A levels in genetically modified mice leads to a complete reversal of the progeroid phenotype, suggesting that inhibition of protein farnesylation could represent a therapeutic option for the treatment of progeria. However, we found that both prelamin A and its truncated form progerin can undergo either farnesylation or geranylgeranylation, revealing the need of targeting both activities for an efficient treatment of HGPS. Using Face-1/Zmpste24-deficient mice as model, we found that a combination of statins and aminobisphosphonates inhibits both types of modifications of prelamin A and progerin, improves the ageing-like symptoms of these mice and extends substantially their longevity, opening a new therapeutic possibility for human progeroid syndromes associated with nuclear-envelope defects. We discuss here the use of this and other animal models to investigate the molecular mechanisms underlying accelerated ageing and to test strategies for its treatment.

  17. Spiked Alloy Production for Accelerated Aging of Plutonium

    SciTech Connect

    Wilk, P A; McNeese, J A; Dodson, K E; Williams, W L; Krikorian, O H; Blau, M S; Schmitz, J E; Bajao, F G; Mew, D A; Matz, T E; Torres, R A; Holck, D M; Moody, K J; Kenneally, J M

    2009-07-10

    The accelerated aging effects on weapons grade plutonium alloys are being studied using {sup 238}Pu-enriched plutonium metal to increase the rate of formation of defect structures. Pyrochemical processing methods have been used to produce two {sup 238}Pu-spiked plutonium alloys with nominal compositions of 7.5 wt% {sup 238}Pu. Processes used in the preparation of the alloys include direct oxide reduction of PuO{sub 2} with calcium and electrorefining. Rolled disks were prepared from the spiked alloys for sampling. Test specimens were cut out of the disks for physical property measurements.

  18. Accelerated aging for testing polymeric biomaterials and medical devices.

    PubMed

    Hukins, D W L; Mahomed, A; Kukureka, S N

    2008-12-01

    Elevated temperature is frequently used to accelerate the aging process in polymers that are associated with medical devices and other applications. A common approach is to assume that the rate of aging is increased by a factor of 2(DeltaT/10), where DeltaT is the temperature increase. This result is a mathematical expression of the empirical observation that increasing the temperature by about 10 degrees C roughly doubles the rate of many polymer reactions. It is equivalent to assuming that the aging process is a first order chemical reaction with an activation energy of 10R/log(e)2, where R is the universal gas constant. A better approach would be to determine the activation energy for the process being considered but this is not always practicable. The simple approach does not depend on the temperature increase, provided that it is not so great that it initiates any physical or chemical process that is unlikely to be involved in normal aging. If a temperature increment theta were to increase a given polymer reaction rate n times, then an elevated temperature would increase the rate of aging by a factor of n(DeltaT/theta).

  19. Anterior cruciate ligament augmentation for rotational instability following primary reconstruction with an accelerated physical therapy protocol.

    PubMed

    Carey, Timothy; Oliver, David; Pniewski, Josh; Mueller, Terry; Bojescul, John

    2013-01-01

    The purpose of the present study is to present the results of anterior cruciate ligament (ACL) augmentation for patients having rotational instability despite an intact vertical graft in lieu of conventional revision ACL reconstruction. ACL augmentation surgery with a horizontal graft was performed to augment a healed vertical graft on five patients and an accelerated rehabilitation protocol was instituted. Functional outcomes were assessed by the Lower Extremity Functional Scale (LEFS) and the Modified Cincinnati Rating System (MCRS). All patients completed physical therapy within 5 months and were able to return to full military duty without limitation. LEFS and MCRS were significantly improved. ACL augmentation with a horizontal graft provides an excellent alternative to ACL revision reconstruction for patients with an intact vertical graft, allowing an earlier return to duty for military service members.

  20. Parasite infection accelerates age polyethism in young honey bees

    PubMed Central

    Lecocq, Antoine; Jensen, Annette Bruun; Kryger, Per; Nieh, James C.

    2016-01-01

    Honey bees (Apis mellifera) are important pollinators and their health is threatened worldwide by persistent exposure to a wide range of factors including pesticides, poor nutrition, and pathogens. Nosema ceranae is a ubiquitous microsporidian associated with high colony mortality. We used lab micro-colonies of honey bees and video analyses to track the effects of N. ceranae infection and exposure on a range of individual and social behaviours in young adult bees. We provide detailed data showing that N. ceranae infection significantly accelerated the age polyethism of young bees, causing them to exhibit behaviours typical of older bees. Bees with high N. ceranae spore counts had significantly increased walking rates and decreased attraction to queen mandibular pheromone. Infected bees also exhibited higher rates of trophallaxis (food exchange), potentially reflecting parasite manipulation to increase colony infection. However, reduction in queen contacts could help bees limit the spread of infection. Such accelerated age polyethism may provide a form of behavioural immunity, particularly if it is elicited by a wide variety of pathogens. PMID:26912310

  1. Parasite infection accelerates age polyethism in young honey bees.

    PubMed

    Lecocq, Antoine; Jensen, Annette Bruun; Kryger, Per; Nieh, James C

    2016-01-01

    Honey bees (Apis mellifera) are important pollinators and their health is threatened worldwide by persistent exposure to a wide range of factors including pesticides, poor nutrition, and pathogens. Nosema ceranae is a ubiquitous microsporidian associated with high colony mortality. We used lab micro-colonies of honey bees and video analyses to track the effects of N. ceranae infection and exposure on a range of individual and social behaviours in young adult bees. We provide detailed data showing that N. ceranae infection significantly accelerated the age polyethism of young bees, causing them to exhibit behaviours typical of older bees. Bees with high N. ceranae spore counts had significantly increased walking rates and decreased attraction to queen mandibular pheromone. Infected bees also exhibited higher rates of trophallaxis (food exchange), potentially reflecting parasite manipulation to increase colony infection. However, reduction in queen contacts could help bees limit the spread of infection. Such accelerated age polyethism may provide a form of behavioural immunity, particularly if it is elicited by a wide variety of pathogens. PMID:26912310

  2. Acrylamide induces accelerated endothelial aging in a human cell model.

    PubMed

    Sellier, Cyril; Boulanger, Eric; Maladry, François; Tessier, Frédéric J; Lorenzi, Rodrigo; Nevière, Rémi; Desreumaux, Pierre; Beuscart, Jean-Baptiste; Puisieux, François; Grossin, Nicolas

    2015-09-01

    Acrylamide (AAM) has been recently discovered in food as a Maillard reaction product. AAM and glycidamide (GA), its metabolite, have been described as probably carcinogenic to humans. It is widely established that senescence and carcinogenicity are closely related. In vitro, endothelial aging is characterized by replicative senescence in which primary cells in culture lose their ability to divide. Our objective was to assess the effects of AAM and GA on human endothelial cell senescence. Human umbilical vein endothelial cells (HUVECs) cultured in vitro were used as model. HUVECs were cultured over 3 months with AAM or GA (1, 10 or 100 μM) until growth arrest. To analyze senescence, β-galactosidase activity and telomere length of HUVECs were measured by cytometry and semi-quantitative PCR, respectively. At all tested concentrations, AAM or GA reduced cell population doubling compared to the control condition (p < 0.001). β-galactosidase activity in endothelial cells was increased when exposed to AAM (≥10 μM) or GA (≥1 μM) (p < 0.05). AAM (≥10 μM) or GA (100 μM) accelerated telomere shortening in HUVECs (p < 0.05). In conclusion, in vitro chronic exposure to AAM or GA at low concentrations induces accelerated senescence. This result suggests that an exposure to AAM might contribute to endothelial aging.

  3. Parasite infection accelerates age polyethism in young honey bees.

    PubMed

    Lecocq, Antoine; Jensen, Annette Bruun; Kryger, Per; Nieh, James C

    2016-02-25

    Honey bees (Apis mellifera) are important pollinators and their health is threatened worldwide by persistent exposure to a wide range of factors including pesticides, poor nutrition, and pathogens. Nosema ceranae is a ubiquitous microsporidian associated with high colony mortality. We used lab micro-colonies of honey bees and video analyses to track the effects of N. ceranae infection and exposure on a range of individual and social behaviours in young adult bees. We provide detailed data showing that N. ceranae infection significantly accelerated the age polyethism of young bees, causing them to exhibit behaviours typical of older bees. Bees with high N. ceranae spore counts had significantly increased walking rates and decreased attraction to queen mandibular pheromone. Infected bees also exhibited higher rates of trophallaxis (food exchange), potentially reflecting parasite manipulation to increase colony infection. However, reduction in queen contacts could help bees limit the spread of infection. Such accelerated age polyethism may provide a form of behavioural immunity, particularly if it is elicited by a wide variety of pathogens.

  4. Accelerated treatment protocols: full arch treatment with interim and definitive prostheses.

    PubMed

    Drago, Carl

    2012-01-01

    With the advent of titanium, root form implants and osseointegration, dental treatment has undergone a metamorphosis in recent years. These new techniques enable dentists to provide anchorage for various kinds of prostheses that improve masticatory function, esthetics, and comfort for patients. Implant treatment protocols have been improved relative to implant macro- and micro-geometries, surgical and prosthetic components, and treatment times. Over the past 20 years, immediate occlusal function (also known as loading) has been established as a predictable treatment modality, provided certain specific criteria are met. In many cases, edentulous patients, crippled by the loss of their teeth, can undergo outpatient surgical and prosthetic procedures and return to a masticatory function that is near normal--sometimes after only one day of surgical and prosthetic treatment. This treatment option is also available for patients with advanced, generalized periodontal disease. Computer-assisted design/Computer-assisted manufacturing (CAD/CAM) has transformed how dental prostheses are made, offering improved accuracy, longevity, and biocompatibility; along with reduced labor costs and fewer complications than casting technologies. This article reviews the principles associated with immediate occlusal loading and illustrates one specific accelerated prosthodontic treatment protocol used to treat edentulous and partially edentulous patients with interim and definitive prostheses.

  5. Ultraweak chemiluminescence of rice seeds during accelerated aging

    NASA Astrophysics Data System (ADS)

    Chen, Wenli; Xing, Da; He, Yonghong

    2002-04-01

    Ultraweak Chemiluminescence (UCL) studies of different aging degree of rice (Oryza sativa L.) seeds stored in a high temperature 40 degree(s)C and high relative humidity 90% environment (0 day, 8 days, 15 days, and 22 days) were carried out. We firstly observed that aging degree of rice seeds was positive correlation with ultraweak chemiluminescence during the early imbibition (0-1h). Addition of water to rice seeds stimulates ultraweak chemiluminescence, the intensity of which depends upon aging degree of seeds. The shorter the seed accelerated aging time was, the higher the intensity of the UCL in the early imbibition period, the lower hydrogen peroxide (H2O2) concentration of rice seeds, the higher percentage seed germination. The germination and superoxide dismutase (SOD) activity of dry rice seeds was obvious positive correlation with the intensity of UCL. While catalase (CAT) activity of rice seeds was determined. Mechanism of ultraweak chemiluminescence was discussed. It was concluded that the store time of rice seeds could be judged from their UCL characters during the early imbibition period, which might be a way to examine vigor of seeds.

  6. Aging of organic materials around high-energy particle accelerators

    NASA Astrophysics Data System (ADS)

    Tavlet, Marc

    1997-08-01

    Around particle accelerators used for fundamental research on the basic structure of matter, materials and components are exposed to ionizing radiation caused by beam losses in the proton machines and by synchrotron radiation in the lepton machines. Furthermore, with the high-energy and high-intensity collisions produced from future colliders, radiation damage is also to be expected in particle-physics detectors. Therefore, for a safe and reliable operation, the radiation aging of most of the components has to be assessed prior to their selection. An extensive radiation-damage test program has been carried out at CERN for decades on a routine basis and many results have been published. The tests have mainly concentrated on magnet-coil insulations and cable-insulating materials; they are carried out in accordance with the IEC 544 standard which defines the mechanical tests to be performed and the methods of degradation evaluation. The mechanical tests are also used to assess the degradation of composite structural materials. Moreover, electrical properties of high-voltage insulations and optical properties of organic scintillators and wave guides have also been studied. Our long-term experience has pointed out many parameters to be taken into account for the estimate of the lifetime of components in the radiation environment of our accelerators. One of the main parameters is the dose-rate effect, but the influence of other parameters has sometimes to be taken into account.

  7. Accelerated Aging System for Prognostics of Power Semiconductor Devices

    NASA Technical Reports Server (NTRS)

    Celaya, Jose R.; Vashchenko, Vladislav; Wysocki, Philip; Saha, Sankalita

    2010-01-01

    Prognostics is an engineering discipline that focuses on estimation of the health state of a component and the prediction of its remaining useful life (RUL) before failure. Health state estimation is based on actual conditions and it is fundamental for the prediction of RUL under anticipated future usage. Failure of electronic devices is of great concern as future aircraft will see an increase of electronics to drive and control safety-critical equipment throughout the aircraft. Therefore, development of prognostics solutions for electronics is of key importance. This paper presents an accelerated aging system for gate-controlled power transistors. This system allows for the understanding of the effects of failure mechanisms, and the identification of leading indicators of failure which are essential in the development of physics-based degradation models and RUL prediction. In particular, this system isolates electrical overstress from thermal overstress. Also, this system allows for a precise control of internal temperatures, enabling the exploration of intrinsic failure mechanisms not related to the device packaging. By controlling the temperature within safe operation levels of the device, accelerated aging is induced by electrical overstress only, avoiding the generation of thermal cycles. The temperature is controlled by active thermal-electric units. Several electrical and thermal signals are measured in-situ and recorded for further analysis in the identification of leading indicators of failures. This system, therefore, provides a unique capability in the exploration of different failure mechanisms and the identification of precursors of failure that can be used to provide a health management solution for electronic devices.

  8. Evaluation of Experimental Parameters in the Accelerated Aging of Closed-Cell Foam Insulation

    SciTech Connect

    Stovall, Therese K; Vanderlan, Michael; Atchley, Jerald Allen

    2012-12-01

    The thermal conductivity of many closed-cell foam insulation products changes over time as production gases diffuse out of the cell matrix and atmospheric gases diffuse into the cells. Thin slicing has been shown to be an effective means of accelerating this process in such a way as to produce meaningful results. Efforts to produce a more prescriptive version of the ASTM C1303 standard test method led to the ruggedness test described here. This test program included the aging of full size insulation specimens for time periods of five years for direct comparison to the predicted results. Experimental parameters under investigation include: slice thickness, slice origin (at the surface or from the core of the slab), thin slice stack composition, product facings, original product thickness, product density, and product type. The test protocol has been completed and this report provides a detailed evaluation of the impact of the test parameters on the accuracy of the 5-year thermal conductivity prediction.

  9. Volatile profile of Madeira wines submitted to traditional accelerated ageing.

    PubMed

    Pereira, Vanda; Cacho, Juan; Marques, José C

    2014-11-01

    The evolution of monovarietal fortified Madeira wines forced-aged by traditional thermal processing (estufagem) were studied in terms of volatiles. SPE extracts were analysed by GC-MS before and after heating at 45 °C for 3 months (standard) and at 70 °C for 1 month (overheating). One hundred and ninety volatile compounds were identified, 53 of which were only encountered in baked wines. Most chemical families increased after standard heating, especially furans and esters, up to 61 and 3-fold, respectively. On the contrary, alcohols, acetates and fatty acids decreased after heating. Varietal aromas, such as Malvasia's monoterpenic alcohols were not detected after baking. The accelerated ageing favoured the development of some volatiles previously reported as typical aromas of finest Madeira wines, particularly phenylacetaldeyde, β-damascenone and 5-ethoxymethylfurfural. Additionally, ethyl butyrate, ethyl 2-methylbutyrate, ethyl caproate, ethyl isovalerate, guaiacol, 5-hydroxymethylfurfural and γ-decalactone were also found as potential contributors to the global aroma of baked wines.

  10. Effects of Accelerated Aging on Fiber Damage Thresholds

    SciTech Connect

    Setchell, R.E.

    1999-02-15

    internal defects. Damage characteristics obtained from fibers subjected to each of these aging environments were compared to results from fresh fibers tested under identical conditions. A surprising result was that internal damage was not observed in any of the tested fibers. Only breakdown at the fiber entrance face and catastrophic damage at both end faces were observed. Fiber end faces were not sealed during the accelerated aging environments, and thresholds at these faces were significantly lower in the aged fibers. However, most fibers transmitted relatively high pulse energies before damaging, and a large fraction never damaged before we reached the limits of our test laser. The absence of any observable affect on internal damage thresholds is encouraging, but the current results do not rule out the possibility that some other approach to accelerated aging could reveal a growth mechanism for internal defects.

  11. Evolution of the microstructure of unmodified and polymer modified asphalt binders with aging in an accelerated weathering tester.

    PubMed

    Menapace, Ilaria; Masad, Eyad

    2016-09-01

    This paper presents findings on the evolution of the surface microstructure of two asphalt binders, one unmodified and one polymer modified, directly exposed to aging agents with increasing durations. The aging is performed using an accelerated weathering tester, where ultraviolet radiation, oxygen and an increased temperature are applied to the asphalt binder surface. Ultraviolet and dark cycles, which simulated the succession of day and night, alternated during the aging process, and also the temperature varied, which corresponded to typical summer day and night temperatures registered in the state of Qatar. Direct aging of an exposed binder surface is more effective in showing microstructural modifications than previously applied protocols, which involved the heat treatment of binders previously aged with standardized methods. With the new protocol, any molecular rearrangements in the binder surface after aging induced by the heat treatment is prevented. Optical photos show the rippling and degradation of the binder surface due to aging. Microstructure images obtained by means of atomic force microscopy show gradual alteration of the surface due to aging. The original relatively flat microstructure was substituted with a profoundly different microstructure, which significantly protrudes from the surface, and is characterized by various shapes, such as rods, round structures and finally 'flower' or 'leaf' structures. PMID:27059404

  12. Evolution of the microstructure of unmodified and polymer modified asphalt binders with aging in an accelerated weathering tester.

    PubMed

    Menapace, Ilaria; Masad, Eyad

    2016-09-01

    This paper presents findings on the evolution of the surface microstructure of two asphalt binders, one unmodified and one polymer modified, directly exposed to aging agents with increasing durations. The aging is performed using an accelerated weathering tester, where ultraviolet radiation, oxygen and an increased temperature are applied to the asphalt binder surface. Ultraviolet and dark cycles, which simulated the succession of day and night, alternated during the aging process, and also the temperature varied, which corresponded to typical summer day and night temperatures registered in the state of Qatar. Direct aging of an exposed binder surface is more effective in showing microstructural modifications than previously applied protocols, which involved the heat treatment of binders previously aged with standardized methods. With the new protocol, any molecular rearrangements in the binder surface after aging induced by the heat treatment is prevented. Optical photos show the rippling and degradation of the binder surface due to aging. Microstructure images obtained by means of atomic force microscopy show gradual alteration of the surface due to aging. The original relatively flat microstructure was substituted with a profoundly different microstructure, which significantly protrudes from the surface, and is characterized by various shapes, such as rods, round structures and finally 'flower' or 'leaf' structures.

  13. The effects of different speed training protocols on sprint acceleration kinematics and muscle strength and power in field sport athletes.

    PubMed

    Lockie, Robert G; Murphy, Aron J; Schultz, Adrian B; Knight, Timothy J; Janse de Jonge, Xanne A K

    2012-06-01

    A variety of resistance training interventions are used to improve field sport acceleration (e.g., free sprinting, weights, plyometrics, resisted sprinting). The effects these protocols have on acceleration performance and components of sprint technique have not been clearly defined in the literature. This study assessed 4 common protocols (free sprint training [FST], weight training [WT], plyometric training [PT], and resisted sprint training [RST]) for changes in acceleration kinematics, power, and strength in field sport athletes. Thirty-five men were divided into 4 groups (FST: n = 9; WT: n = 8; PT: n = 9; RST: n = 9) matched for 10-m velocity. Training involved two 60-minute sessions per week for 6 weeks. After the interventions, paired-sample t-tests identified significant (p ≤ 0.05) within-group changes. All the groups increased the 0- to 5-m and 0- to 10-m velocity by 9-10%. The WT and PT groups increased the 5- to 10-m velocity by approximately 10%. All the groups increased step length for all distance intervals. The FST group decreased 0- to 5-m flight time and step frequency in all intervals and increased 0- to 5-m and 0- to 10-m contact time. Power and strength adaptations were protocol specific. The FST group improved horizontal power as measured by a 5-bound test. The FST, PT, and RST groups all improved reactive strength index derived from a 40-cm drop jump, indicating enhanced muscle stretch-shortening capacity during rebound from impacts. The WT group increased absolute and relative strength measured by a 3-repetition maximum squat by approximately 15%. Step length was the major limiting sprint performance factor for the athletes in this study. Correctly administered, each training protocol can be effective in improving acceleration. To increase step length and improve acceleration, field sport athletes should develop specific horizontal and reactive power. PMID:21912294

  14. The effects of different speed training protocols on sprint acceleration kinematics and muscle strength and power in field sport athletes.

    PubMed

    Lockie, Robert G; Murphy, Aron J; Schultz, Adrian B; Knight, Timothy J; Janse de Jonge, Xanne A K

    2012-06-01

    A variety of resistance training interventions are used to improve field sport acceleration (e.g., free sprinting, weights, plyometrics, resisted sprinting). The effects these protocols have on acceleration performance and components of sprint technique have not been clearly defined in the literature. This study assessed 4 common protocols (free sprint training [FST], weight training [WT], plyometric training [PT], and resisted sprint training [RST]) for changes in acceleration kinematics, power, and strength in field sport athletes. Thirty-five men were divided into 4 groups (FST: n = 9; WT: n = 8; PT: n = 9; RST: n = 9) matched for 10-m velocity. Training involved two 60-minute sessions per week for 6 weeks. After the interventions, paired-sample t-tests identified significant (p ≤ 0.05) within-group changes. All the groups increased the 0- to 5-m and 0- to 10-m velocity by 9-10%. The WT and PT groups increased the 5- to 10-m velocity by approximately 10%. All the groups increased step length for all distance intervals. The FST group decreased 0- to 5-m flight time and step frequency in all intervals and increased 0- to 5-m and 0- to 10-m contact time. Power and strength adaptations were protocol specific. The FST group improved horizontal power as measured by a 5-bound test. The FST, PT, and RST groups all improved reactive strength index derived from a 40-cm drop jump, indicating enhanced muscle stretch-shortening capacity during rebound from impacts. The WT group increased absolute and relative strength measured by a 3-repetition maximum squat by approximately 15%. Step length was the major limiting sprint performance factor for the athletes in this study. Correctly administered, each training protocol can be effective in improving acceleration. To increase step length and improve acceleration, field sport athletes should develop specific horizontal and reactive power.

  15. Insight into the effects of different ageing protocols on Rh/Al2O3 catalyst

    NASA Astrophysics Data System (ADS)

    Zhao, Baohuai; Ran, Rui; Cao, Yidan; Wu, Xiaodong; Weng, Duan; Fan, Jun; Wu, Xueyuan

    2014-07-01

    In this work, a catalyst of Rh loaded on Al2O3 was prepared by impregnating method with rhodium nitrate aqueous solution as the Rh precursor. The catalyst was aged under different protocols (lean, rich, inert and cyclic) to obtain several aged samples. All the Rh/Al2O3 samples were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method, CO-chemisorption, H2-temperature programmed reduction (H2-TPR), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). It was found that a specific ageing treatment could strongly affect the catalytic activity. The N2 aged and the H2 aged samples had a better catalytic activity for CO + NO reaction than the fresh sample while the air aged and the cyclic aged samples exhibited much worse activity. More surface Rh content and better reducibility were obtained in the N2 and the H2 aged samples and the Rh particles existed with an appropriate size, which were all favorable to the catalytic reaction. However, the air and the cyclic ageing protocols induced a strong interaction between Rh species and the Al2O3 support, which resulted in a severe sintering of particles of Rh species and the loss of active sites. The structure evolution scheme of the catalysts aged in different protocols was also established in this paper.

  16. Accelerated aging studies and environmental stability of prototype tamper tapes

    SciTech Connect

    Wright, B.W.; Wright, C.W.; Bunk, A.R.

    1995-05-01

    This report describes the results of accelerated aging experiments (weathering) conducted on prototype tamper tapes bonded to a variety of surface materials. The prototype tamper tapes were based on the patented Confirm{reg_sign} tamper-indicating technology developed and produced by 3M Company. Tamper tapes bonded to surfaces using pressure sensitive adhesive (PSA) and four rapid-set adhesives were evaluated. The configurations of the PSA-bonded tamper tapes were 1.27-cm-wide Confirm{reg_sign} 1700 windows with vinyl underlay and 2.54-cm-wide Confirm{reg_sign} 1700 windows with vinyl and polyester underlays. The configurations of the rapid-set adhesive-bonded tamper tapes were 2.54-cm-wide Confirm{reg_sign} (1700, 1500 with and without primer, and 1300) windows with vinyl underlay. Surfaces used for bonding included aluminum, steel, stainless steel, Kevlar{reg_sign}, brass, copper, fiberglass/resin with and without gel coat, polyurethane-painted steel, acrylonitrile:butadiene:styrene plastic, polyester fiberglass board, Lexan polycarbonate, and cedar wood. Weathering conditions included a QUV cabinet (ultraviolet light at 60{degrees}C, condensing humidity at 40{degrees}C), a thermal cycling cabinet (-18{degrees}C to 46{degrees}C), a Weather-O-Meter (Xenon lamp), and exposure outdoors in Daytona Beach, Florida. Environmental aging exposures lasted from 7 weeks to 5 months. After exposure, the tamper tapes were visually examined and tested for transfer resistance. Tamper tapes were also exposed to a variety of chemical liquids (including organic solvents, acids, bases, and oxidizing liquids) to determine chemical resistance and to sand to determine abrasion resistance.

  17. Clinical Experience With Image-Guided Radiotherapy in an Accelerated Partial Breast Intensity-Modulated Radiotherapy Protocol

    SciTech Connect

    Leonard, Charles E.; Tallhamer, Michael M.S.; Johnson, Tim; Hunter, Kari C.M.D.; Howell, Kathryn; Kercher, Jane; Widener, Jodi; Kaske, Terese; Paul, Devchand; Sedlacek, Scot; Carter, Dennis L.

    2010-02-01

    Purpose: To explore the feasibility of fiducial markers for the use of image-guided radiotherapy (IGRT) in an accelerated partial breast intensity modulated radiotherapy protocol. Methods and Materials: Nineteen patients consented to an institutional review board approved protocol of accelerated partial breast intensity-modulated radiotherapy with fiducial marker placement and treatment with IGRT. Patients (1 patient with bilateral breast cancer; 20 total breasts) underwent ultrasound guided implantation of three 1.2- x 3-mm gold markers placed around the surgical cavity. For each patient, table shifts (inferior/superior, right/left lateral, and anterior/posterior) and minimum, maximum, mean error with standard deviation were recorded for each of the 10 BID treatments. The dose contribution of daily orthogonal films was also examined. Results: All IGRT patients underwent successful marker placement. In all, 200 IGRT treatment sessions were performed. The average vector displacement was 4 mm (range, 2-7 mm). The average superior/inferior shift was 2 mm (range, 0-5 mm), the average lateral shift was 2 mm (range, 1-4 mm), and the average anterior/posterior shift was 3 mm (range, 1 5 mm). Conclusions: This study shows that the use of IGRT can be successfully used in an accelerated partial breast intensity-modulated radiotherapy protocol. The authors believe that this technique has increased daily treatment accuracy and permitted reduction in the margin added to the clinical target volume to form the planning target volume.

  18. Color stability of repaired composite submitted to accelerated artificial aging.

    PubMed

    Souza, Ana Beatriz Silva; Silame, Francisca Daniele Jardilino; Alandia-Roman, Carla Cecilia; Cruvinel, Diogo Rodrigues; Garcia, Lucas da Fonseca Roberti; Pires-de-Souza, Fernanda de Carvalho Panzeri

    2012-01-01

    The aim of this study was to evaluate the color stability (ΔE) of nanoparticulate composite, with consideration for the type of surface treatment performed before repair. A Teflon matrix was used to fabricate 50 test specimens from composite. After initial color readout, the specimens were submitted to 100 hours of accelerated artificial aging (AAA). The samples were divided into five groups (n = 10), according to the surface treatment performed: sandblasting with aluminum oxide powder, phosphoric acid, and an adhesive system (Group 1); sandblasting with aluminum oxide powder, phosphoric acid, and a flowable composite (Group 2); abrasion with a diamond bur, phosphoric acid, and an adhesive system (Group 3); abrasion with a diamond bur, phosphoric acid, and a nanoparticulate composite (Group 4); and a control group (Group 5). After repair, a new color readout was taken, the test specimens were submitted to a new AAA cycle (300 hours), and the final color readout was taken. Comparison of the ΔE means (one-way ANOVA and Tukey tests, p < 0.05) demonstrated no statistically significant differences among the groups (p > 0.05) after 100 hours of AAA. After repair, Group 1 (4.61 ± 2.03) presented the highest color alteration with a statistically significant difference compared with the other groups (p < 0.05). After 300 hours, Group 4 specimens (13.84 ± 0.71) presented the lowest color alteration in comparison with the other groups, with a statistically significant difference (p < 0.05). It was concluded that the repair performed in Group 4 provided greater esthetic recovery, made possible by the regression in the ΔE values of the restorations after repair, and less color alteration of the restorations over the course of time. PMID:23032241

  19. Protocols and Programs for High-Throughput Growth and Aging Phenotyping in Yeast

    PubMed Central

    Jung, Paul P.; Christian, Nils; Kay, Daniel P.; Skupin, Alexander; Linster, Carole L.

    2015-01-01

    In microorganisms, and more particularly in yeasts, a standard phenotyping approach consists in the analysis of fitness by growth rate determination in different conditions. One growth assay that combines high throughput with high resolution involves the generation of growth curves from 96-well plate microcultivations in thermostated and shaking plate readers. To push the throughput of this method to the next level, we have adapted it in this study to the use of 384-well plates. The values of the extracted growth parameters (lag time, doubling time and yield of biomass) correlated well between experiments carried out in 384-well plates as compared to 96-well plates or batch cultures, validating the higher-throughput approach for phenotypic screens. The method is not restricted to the use of the budding yeast Saccharomyces cerevisiae, as shown by consistent results for other species selected from the Hemiascomycete class. Furthermore, we used the 384-well plate microcultivations to develop and validate a higher-throughput assay for yeast Chronological Life Span (CLS), a parameter that is still commonly determined by a cumbersome method based on counting “Colony Forming Units”. To accelerate analysis of the large datasets generated by the described growth and aging assays, we developed the freely available software tools GATHODE and CATHODE. These tools allow for semi-automatic determination of growth parameters and CLS behavior from typical plate reader output files. The described protocols and programs will increase the time- and cost-efficiency of a number of yeast-based systems genetics experiments as well as various types of screens. PMID:25822370

  20. Treadmill exercise induces age and protocol-dependent epigenetic changes in prefrontal cortex of Wistar rats.

    PubMed

    Cechinel, Laura Reck; Basso, Carla Giovana; Bertoldi, Karine; Schallenberger, Bruna; de Meireles, Louisiana Carolina Ferreira; Siqueira, Ionara Rodrigues

    2016-10-15

    Some studies have linked age-related beneficial effects of exercise and epigenetic mechanisms. Although, the impact of treadmill exercise on histone acetylation, histone and DNA methylation marks in aged cortices yet remains poorly understood. Considering the role of frontal cortex on brain functions, we investigated the potential of different exercise protocols, single session and daily exercise, to modulate epigenetic marks, namely global H4 acetylation, histone methyltransferase activity (HMT H3K27) and levels of DNA methytransferase (DNMT1 and DNMT3b) in prefrontal cortices from 3 and 21-months aged Wistar rats. The animals were submitted to two treadmill exercise protocols, single session (20min) or daily moderate (20min/day during 14days). The daily exercise protocol induced an increased in histone H4 acetylation levels in prefrontal cortices of 21-months-old rats, without any effects in young adult group. DNMT3b levels were increased in aged cortices of animals submitted to single session of exercise. These results indicate that prefrontal cortex is susceptible to epigenetic changes in a protocol dependent-manner and that H4 acetylation levels and DNMT3b content changes might be linked at least in part to exercise-induced effects on brain functions. PMID:27418438

  1. Treadmill exercise induces age and protocol-dependent epigenetic changes in prefrontal cortex of Wistar rats.

    PubMed

    Cechinel, Laura Reck; Basso, Carla Giovana; Bertoldi, Karine; Schallenberger, Bruna; de Meireles, Louisiana Carolina Ferreira; Siqueira, Ionara Rodrigues

    2016-10-15

    Some studies have linked age-related beneficial effects of exercise and epigenetic mechanisms. Although, the impact of treadmill exercise on histone acetylation, histone and DNA methylation marks in aged cortices yet remains poorly understood. Considering the role of frontal cortex on brain functions, we investigated the potential of different exercise protocols, single session and daily exercise, to modulate epigenetic marks, namely global H4 acetylation, histone methyltransferase activity (HMT H3K27) and levels of DNA methytransferase (DNMT1 and DNMT3b) in prefrontal cortices from 3 and 21-months aged Wistar rats. The animals were submitted to two treadmill exercise protocols, single session (20min) or daily moderate (20min/day during 14days). The daily exercise protocol induced an increased in histone H4 acetylation levels in prefrontal cortices of 21-months-old rats, without any effects in young adult group. DNMT3b levels were increased in aged cortices of animals submitted to single session of exercise. These results indicate that prefrontal cortex is susceptible to epigenetic changes in a protocol dependent-manner and that H4 acetylation levels and DNMT3b content changes might be linked at least in part to exercise-induced effects on brain functions.

  2. Free radical entrapment and crystallinity of resin composites after accelerated aging as a function of the expiration date.

    PubMed

    D'Alpino, Paulo Henrique Perlatti; Vismara, Marcos Vinícius Gonçalves; González, Alejandra Hortencia Miranda; Graeff, Carlos Frederico de Oliveira

    2014-08-01

    This study evaluated the spin concentration and the crystallinity in different classifications of dental composites as a function of the material condition (new, aged and expired). Specimens were obtained according to the factors: composites: Filtek P60, Filtek Z250, Filtek Z350XT, and Filtek Silorane; and material conditions: new, aged, and expired. The syringe composites underwent an accelerated aging protocol (Arrhenius model). The magnetic properties of the composites were characterized using Electron Paramagnetic Resonance (EPR) and the concentration of spins (number of spins/mass) was calculated. The crystallinity of the composites tested was characterized with X-ray diffraction (XRD). Filtek P60 and Filtek Z250 presented similarities in terms of spin concentration and crystallinity, irrespective of the material condition. The aging protocol influenced the composite Filtek Z350XT that exhibited a significant increase in the spin concentration. Besides, lower intensity peaks of the organic matrix and amorphous silica were also observed for both aged and expired Filtek Z350XT. Although a significant lower spin concentration was observed for the silorane composite in comparison to that of the methacrylates, a decrease in the relative intensity of peaks of the amorphous region related to the organic components in the diffractograms was observed. The material conditions tested influence the crystallinity and the magnetic properties of the composites evaluated.

  3. Accelerated aging of extruded dielectric power cables. Part 1; Control and monitoring methodology

    SciTech Connect

    Walton, M.S.; Smith, J.T. III ); Thue, W.A. )

    1992-04-01

    In accelerated cable life testing of power cables, cable samples are usually subjected to elevated voltages and temperatures in the presence of water in order to promote aging of the insulation and premature failures through the treeing mechanism. Failure to accurately control and monitor these accelerating facts can have adverse effects on test results and can lead to erroneous conclusions. In this paper, a new and improved accelerated cable life test is described. Through the use of programmable logic controllers (PLCs), very precise and consistent control of the accelerated aging process has been achieved. A computer has been utilized to make continuous real-time data acquisition and storage to key operating parameters possible. This precise control of monitoring methodology has permitted the study of the synergistic effects of voltage and temperature on the accelerated aging of full-sized cables in the laboratory.

  4. GPU-Accelerated Molecular Modeling Coming Of Age

    PubMed Central

    Stone, John E.; Hardy, David J.; Ufimtsev, Ivan S.

    2010-01-01

    Graphics processing units (GPUs) have traditionally been used in molecular modeling solely for visualization of molecular structures and animation of trajectories resulting from molecular dynamics simulations. Modern GPUs have evolved into fully programmable, massively parallel co-processors that can now be exploited to accelerate many scientific computations, typically providing about one order of magnitude speedup over CPU code and in special cases providing speedups of two orders of magnitude. This paper surveys the development of molecular modeling algorithms that leverage GPU computing, the advances already made and remaining issues to be resolved, and the continuing evolution of GPU technology that promises to become even more useful to molecular modeling. Hardware acceleration with commodity GPUs is expected to benefit the overall computational biology community by bringing teraflops performance to desktop workstations and in some cases potentially changing what were formerly batch-mode computational jobs into interactive tasks. PMID:20675161

  5. Huntington's disease accelerates epigenetic aging of human brain and disrupts DNA methylation levels

    PubMed Central

    Horvath, Steve; Langfelder, Peter; Kwak, Seung; Aaronson, Jeff; Rosinski, Jim; Vogt, Thomas F.; Eszes, Marika; Faull, Richard L.M.; Curtis, Maurice A.; Waldvogel, Henry J.; Choi, Oi-Wa; Tung, Spencer; Vinters, Harry V.; Coppola, Giovanni; Yang, X. William

    2016-01-01

    Age of Huntington's disease (HD) motoric onset is strongly related to the number of CAG trinucleotide repeats in the huntingtin gene, suggesting that biological tissue age plays an important role in disease etiology. Recently, a DNA methylation based biomarker of tissue age has been advanced as an epigenetic aging clock. We sought to inquire if HD is associated with an accelerated epigenetic age. DNA methylation data was generated for 475 brain samples from various brain regions of 26 HD cases and 39 controls. Overall, brain regions from HD cases exhibit a significant epigenetic age acceleration effect (p=0.0012). A multivariate model analysis suggests that HD status increases biological age by 3.2 years. Accelerated epigenetic age can be observed in specific brain regions (frontal lobe, parietal lobe, and cingulate gyrus). After excluding controls, we observe a negative correlation (r=−0.41, p=5.5×10−8) between HD gene CAG repeat length and the epigenetic age of HD brain samples. Using correlation network analysis, we identify 11 co-methylation modules with a significant association with HD status across 3 broad cortical regions. In conclusion, HD is associated with an accelerated epigenetic age of specific brain regions and more broadly with substantial changes in brain methylation levels. PMID:27479945

  6. Huntington's disease accelerates epigenetic aging of human brain and disrupts DNA methylation levels.

    PubMed

    Horvath, Steve; Langfelder, Peter; Kwak, Seung; Aaronson, Jeff; Rosinski, Jim; Vogt, Thomas F; Eszes, Marika; Faull, Richard L M; Curtis, Maurice A; Waldvogel, Henry J; Choi, Oi-Wa; Tung, Spencer; Vinters, Harry V; Coppola, Giovanni; Yang, X William

    2016-07-01

    Age of Huntington's disease (HD) motoric onset is strongly related to the number of CAG trinucleotide repeats in the huntingtin gene, suggesting that biological tissue age plays an important role in disease etiology. Recently, a DNA methylation based biomarker of tissue age has been advanced as an epigenetic aging clock. We sought to inquire if HD is associated with an accelerated epigenetic age. DNA methylation data was generated for 475 brain samples from various brain regions of 26 HD cases and 39 controls. Overall, brain regions from HD cases exhibit a significant epigenetic age acceleration effect (p=0.0012). A multivariate model analysis suggests that HD status increases biological age by 3.2 years. Accelerated epigenetic age can be observed in specific brain regions (frontal lobe, parietal lobe, and cingulate gyrus). After excluding controls, we observe a negative correlation (r=-0.41, p=5.5×10-8) between HD gene CAG repeat length and the epigenetic age of HD brain samples. Using correlation network analysis, we identify 11 co-methylation modules with a significant association with HD status across 3 broad cortical regions. In conclusion, HD is associated with an accelerated epigenetic age of specific brain regions and more broadly with substantial changes in brain methylation levels. PMID:27479945

  7. Efficacy and toxicity of an accelerated hypofractionated radiation therapy protocol in cats with oral squamous cell carcinoma.

    PubMed

    Poirier, Valérie J; Kaser-Hotz, Barbara; Vail, David M; Straw, Rodney C

    2013-01-01

    Squamous cell carcinoma (SCC) is the most common feline oral tumor. Standard radiation protocols have been reported to achieve tumor control durations of 1.5-5.5 months (45-165 days). The purpose of this study was to describe the efficacy and toxicity of an accelerated hypofractionated radiation therapy protocol in cats with oral SCC. Twenty-one cats with histologically confirmed oral SCC and T1-3N0M0 were treated with 10 once-daily fractions (Monday-Friday) of 4.8 Gy. Seventeen cats had macroscopic disease and four were microscopic after incomplete excision. Acute toxicity consisted of grade 2 mucositis in all cats and this was effectively managed using esophageal or gastric tube feeding, pain medication, and antibiotics. Late toxicity effects for cats with available follow-up data included alopecia (4 cats), leukotricia (6), tongue ulceration (1), and oronasal fistula (1). Response could be assessed in 17 cats (seven complete response and five partial response). Four cats (19%) developed metastatic disease without evidence of local progression. The median progression-free survival (PFS) was 105 days (1 year PFS of 23%), median local progression-free survival (LPFS) was 219 days (1 year LPFS of 41%), and median overall survival (OS) was 174 days (1 year OS of 29%). Only tumor stage was prognostic, with T1 having a median PFS of 590 days. Findings indicated that this accelerated hypofractionated radiation therapy protocol was well tolerated in cats with oral SCC, with manageable adverse events. Tumor response was observed in most cats and long tumor control durations were achieved in some cats.

  8. Nylon 6.6 accelerated aging studies : thermal-oxidative degradation and its interaction with hydrolysis.

    SciTech Connect

    Bernstein, Robert; Derzon, Dora Kay; Gillen, Kenneth T.

    2004-06-01

    Accelerated aging of Nylon 6.6 fibers used in parachutes has been conducted by following the tensile strength loss under both thermal-oxidative and 100% relative humidity conditions. Thermal-oxidative studies (air circulating ovens) were performed for time periods of weeks to years at temperatures ranging from 37 C to 138 C. Accelerated aging humidity experiments (100% RH) were performed under both an argon atmosphere to examine the 'pure' hydrolysis pathway, and under an oxygen atmosphere (oxygen partial pressure close to that occurring in air) to mimic true aging conditions. As expected the results indicated that degradation caused by humidity is much more important than thermal-oxidative degradation. Surprisingly when both oxygen and humidity were present the rate of degradation was dramatically enhanced relative to humidity aging in the absence of oxygen. This significant and previously unknown phenomena underscores the importance of careful accelerated aging that truly mimics real world storage conditions.

  9. Accelerated heat-aging studies on fluororubber in various media

    NASA Technical Reports Server (NTRS)

    Kalfayan, S. H.; Silver, R. H.; Liu, S. S.

    1976-01-01

    Heat-aging studies were conducted on fluororubber (copolymers of vinylidene fluoride and perfluoropropylene) using N,N-dicinnamylidene-1,6-hexanediamine, a Schiff's base of 1,6-hexanediamine, and MgO as acid acceptor. The principal technique employed was chemical stress relaxation for determining network changes brought about in the heat-aged fluororubber. This technique was backed up by swelling measurements, gel permeation chromatography, and IR spectroscopy. Stress relaxation curves are plotted for a wide range of variation in parameters (time, crosslinking density, state of curing, temperature, intermittent and continuous relaxation).

  10. Rapamycin suppresses brain aging in senescence-accelerated OXYS rats.

    PubMed

    Kolosova, Nataliya G; Vitovtov, Anton O; Muraleva, Natalia A; Akulov, Andrey E; Stefanova, Natalia A; Blagosklonny, Mikhail V

    2013-06-01

    Cellular and organismal aging are driven in part by the MTOR (mechanistic target of rapamycin) pathway and rapamycin extends life span inC elegans, Drosophila and mice. Herein, we investigated effects of rapamycin on brain aging in OXYS rats. Previously we found, in OXYS rats, an early development of age-associated pathological phenotypes similar to several geriatric disorders in humans, including cerebral dysfunctions. Behavioral alterations as well as learning and memory deficits develop by 3 months. Here we show that rapamycin treatment (0.1 or 0.5 mg/kg as a food mixture daily from the age of 1.5 to 3.5 months) decreased anxiety and improved locomotor and exploratory behavior in OXYS rats. In untreated OXYS rats, MRI revealed an increase of the area of hippocampus, substantial hydrocephalus and 2-fold increased area of the lateral ventricles. Rapamycin treatment prevented these abnormalities, erasing the difference between OXYS and Wister rats (used as control). All untreated OXYS rats showed signs of neurodegeneration, manifested by loci of demyelination. Rapamycin decreased the percentage of animals with demyelination and the number of loci. Levels of Tau and phospho-Tau (T181) were increased in OXYS rats (compared with Wistar). Rapamycin significantly decreased Tau and inhibited its phosphorylation in the hippocampus of OXYS and Wistar rats. Importantly, rapamycin treatment caused a compensatory increase in levels of S6 and correspondingly levels of phospo-S6 in the frontal cortex, indicating that some downstream events were compensatory preserved, explaining the lack of toxicity. We conclude that rapamycin in low chronic doses can suppress brain aging.

  11. WOODSTOVE DURABILITY TESTING PROTOCOL

    EPA Science Inventory

    The report discusses the development of an accelerated laboratory test to simulate in-home woodstove aging and degradation. nown as a stress test, the protocol determines the long-term durability of woodstove models in a 1- to 2-week time frame. wo avenues of research have been t...

  12. Low intensity laser therapy accelerates muscle regeneration in aged rats

    PubMed Central

    Vatansever, Fatma; Rodrigues, Natalia C.; Assis, Livia L.; Peviani, Sabrina S.; Durigan, Joao L.; Moreira, Fernando M.A.; Hamblin, Michael R.; Parizotto, Nivaldo A.

    2013-01-01

    Background Elderly people suffer from skeletal muscle disorders that undermine their daily activity and quality of life; some of these problems can be listed as but not limited to: sarcopenia, changes in central and peripheral nervous system, blood hypoperfusion, regenerative changes contributing to atrophy, and muscle weakness. Determination, proliferation and differentiation of satellite cells in the regenerative process are regulated by specific transcription factors, known as myogenic regulatory factors (MRFs). In the elderly, the activation of MRFs is inefficient which hampers the regenerative process. Recent studies found that low intensity laser therapy (LILT) has a stimulatory effect in the muscle regeneration process. However, the effects of this therapy when associated with aging are still unknown. Objective This study aimed to evaluate the effects of LILT (λ=830 nm) on the tibialis anterior (TA) muscle of aged rats. Subjects and methods The total of 56 male Wistar rats formed two population sets: old and young, with 28 animals in each set. Each of these sets were randomly divided into four groups of young rats (3 months of age) with n=7 per group and four groups of aged rats (10 months of age) with n=7 per group. These groups were submitted to cryoinjury + laser irradiation, cryoinjury only, laser irradiation only and the control group (no cryoinjury/no laser irradiation). The laser treatment was performed for 5 consecutive days. The first laser application was done 24 h after the injury (on day 2) and on the seventh day, the TA muscle was dissected and removed under anesthesia. After this the animals were euthanized. Histological analyses with toluidine blue as well as hematoxylin-eosin staining (for counting the blood capillaries) were performed for the lesion areas. In addition, MyoD and VEGF mRNA was assessed by quantitative polymerase chain reaction. Results The results showed significant elevation (p<0.05) in MyoD and VEGF genes expression levels

  13. Effect of accelerated aging on the viscoelastic properties of a medical grade silicone.

    PubMed

    Mahomed, Aziza; Hukins, David W L; Kukureka, Stephen N

    2015-01-01

    The viscoelastic properties of cylinders (diameter 5 mm, height 2.2 ± 0.2 mm) of Nagor silicone elastomer of medium hardness, were investigated before and after the specimens had undergone accelerated aging in saline solution at 70°C for 38, 76 and 114 days (to simulate aging at 37°C, for 1, 2 and 3 years, respectively). All sets of specimens were immersed in physiological saline solution at 37°C during testing and the properties were measured using dynamic mechanical analysis (DMA). A sinusoidal cyclic compression of 40 N ± 5 N was applied over a frequency range, f, of 0.02-25 Hz. Values of the storage, E', and loss, E″, moduli were found to depend on f; the dependence of E' or E″ on the logarithm (base 10) of f was represented by a second-order polynomial. After accelerated aging, the E' and E″ values did not increase significantly (p<0.05). Furthermore, scanning electron microscopy (SEM) showed that accelerated aging did not affect the surface morphology of silicone. Attenuated total reflectance Fourier transform infra-red spectroscopy (ATR-FTIR) showed that accelerated aging had a negligible effect on the surface chemical structures of the material. Differential scanning calorimetry (DSC) showed no changes to the bulk properties of silicone, following accelerated aging.

  14. Traumatic stress, oxidative stress and posttraumatic stress disorder: neurodegeneration and the accelerated-aging hypothesis

    PubMed Central

    Miller, Mark W.; Sadeh, Naomi

    2014-01-01

    Posttraumatic stress disorder (PTSD) is associated with elevated risk for a variety of age-related diseases and neurodegeneration. In this paper, we review evidence relevant to the hypothesis that chronic PTSD constitutes a form of persistent life stress that potentiates oxidative stress (OXS) and accelerates cellular aging. We provide an overview of empirical studies that have examined the effects of psychological stress on OXS, discuss the stress-perpetuating characteristics of PTSD, and then identify mechanisms by which PTSD might promote OXS and accelerated aging. We review studies on OXS-related genes and the role that they may play in moderating the effects of PTSD on neural integrity and conclude with a discussion of directions for future research on antioxidant treatments and biomarkers of accelerated aging in PTSD. PMID:25245500

  15. Physical Property Changes in Plutonium from Accelerated Aging using Pu-238 Enrichment

    SciTech Connect

    Chung, B W; Choi, B W; Saw, C K; Thompson, S R; Woods, C H; Hopkins, D J; Ebbinghaus, B B

    2006-12-20

    We present changes in volume, immersion density, and tensile properties observed from accelerated aged plutonium alloys. Accelerated alloys (or spiked alloys) are plutonium alloys enriched with approximately 7.5 weight percent of the faster-decaying {sup 238}Pu to accelerate the aging process by approximately 17 times the rate of unaged weapons-grade plutonium. After sixty equivalent years of aging on spiked alloys, the dilatometry shows the samples at 35 C have swelled in volume by 0.15 to 0.17 % and now exhibit a near linear volume increase due to helium in-growth. The immersion density of spiked alloys shows a decrease in density, similar normalized volumetric changes (expansion) for spiked alloys. Tensile tests show increasing yield and engineering ultimate strength as spiked alloys are aged.

  16. Accelerated thermal aging of petroleum-based ferrofluids

    NASA Astrophysics Data System (ADS)

    Segal, V.; Nattrass, D.; Raj, K.; Leonard, D.

    1999-07-01

    The effect of elevated temperature on the physical and insulating properties of ferrofluid specifically developed for use as a liquid dielectric (D-fluid) for power transformers has been investigated. The D-fluid was produced as a colloidal mix of a specifically synthesized ferrofluid with a conventional mineral oil, and it was subjected to thermal aging conditions modeled after a typical power transformer where the insulation fluid is expected to retain its dielectric performance for about 40 years of continuous service in a sealed tank. The well-known Arrhenius relationship was employed to model "life in service" for up to 40 years at 105°C which corresponded to holding the samples in sealed jars for 10 weeks at 185°C. Another set of small ampules (5 ml) was prepared to test the main physical properties after even longer aging. D-fluid tested after a period of 34 and 50 weeks at 185°C showed no degradation of thermal or colloid stability. The dielectric colloid was also subjected to a 21 day-long test at 110°C in a sealed jar in the presence of typical transformer materials: copper, cellulose, and silicon steel (so-called "bomb" test). Finally, the ferrofluid went through an oxidation stability test (ASTM D2440). Test results show that the newly developed dielectric colloid satisfies the long-term service requirements the transformer users typically apply to conventional mineral oils.

  17. Fluorescence intensity of resin composites and dental tissues before and after accelerated aging: a comparative study.

    PubMed

    Takahashi, Marcos Kenzo; Vieira, Sergio; Rached, Rodrigo Nunes; de Almeida, Janaina Bertoncelo; Aguiar, Marcelo; de Souza, Evelise Machado

    2008-01-01

    This study quantitatively evaluated the fluorescence intensity of resin composites with different opacities and translucencies and determined changes in fluorescence after accelerated aging, using human enamel and dentin as controls. Six microhybrid and nanofilled composites, each in three different shades, were tested. Ten sound human incisors were used to obtain enamel and dentin specimens separately. Fluorescence measurements were obtained with a fluorescence spectrophotometer before (baseline) and after accelerated aging at 150 kJ energy for 120 hours. One-way analysis of variance (ANOVA) and Games-Howell multiple comparison tests were performed at a significance level of 0.05. Student's t-test was also used for comparison before and after aging. At baseline, there was no statistically significant difference (p>0.05) between the fluorescence intensity of dentin and any of the shades of Charisma or Opallis, Esthet-X dentin shade or Vit-l-escence enamel, or the translucent shades. After accelerated aging, all shades of the 4 Seasons, enamel and the translucent shades of Esthet-X had fluorescence intensities statistically similar to that of aged dentin (p>0.05). A significant reduction in fluorescence after aging (p<0.05) was observed for all the materials, except for human enamel and translucent Filtek Supreme XT. Accelerated aging reduced fluorescence in most of the composites evaluated.

  18. Are Anxiety Disorders Associated with Accelerated Aging? A Focus on Neuroprogression

    PubMed Central

    Perna, Giampaolo; Iannone, Giuseppe; Alciati, Alessandra; Caldirola, Daniela

    2016-01-01

    Anxiety disorders (AnxDs) are highly prevalent throughout the lifespan, with detrimental effects on daily-life functioning, somatic health, and quality of life. An emerging perspective suggested that AnxDs may be associated with accelerated aging. In this paper, we explored the association between AnxDs and hallmarks of accelerated aging, with a specific focus on neuroprogression. We reviewed animal and human findings that suggest an overlap between processes of impaired neurogenesis, neurodegeneration, structural, functional, molecular, and cellular modifications in AnxDs, and aging. Although this research is at an early stage, our review suggests a link between anxiety and accelerated aging across multiple processes involved in neuroprogression. Brain structural and functional changes that accompany normal aging were more pronounced in subjects with AnxDs than in coevals without AnxDs, including reduced grey matter density, white matter alterations, impaired functional connectivity of large-scale brain networks, and poorer cognitive performance. Similarly, molecular correlates of brain aging, including telomere shortening, Aβ accumulation, and immune-inflammatory and oxidative/nitrosative stress, were overrepresented in anxious subjects. No conclusions about causality or directionality between anxiety and accelerated aging can be drawn. Potential mechanisms of this association, limitations of the current research, and implications for treatments and future studies are discussed. PMID:26881136

  19. Models of accelerated sarcopenia: critical pieces for solving the puzzle of age-related muscle atrophy.

    PubMed

    Buford, Thomas W; Anton, Stephen D; Judge, Andrew R; Marzetti, Emanuele; Wohlgemuth, Stephanie E; Carter, Christy S; Leeuwenburgh, Christiaan; Pahor, Marco; Manini, Todd M

    2010-10-01

    Sarcopenia, the age-related loss of skeletal muscle mass, is a significant public health concern that continues to grow in relevance as the population ages. Certain conditions have the strong potential to coincide with sarcopenia to accelerate the progression of muscle atrophy in older adults. Among these conditions are co-morbid diseases common to older individuals such as cancer, kidney disease, diabetes, and peripheral artery disease. Furthermore, behaviors such as poor nutrition and physical inactivity are well-known to contribute to sarcopenia development. However, we argue that these behaviors are not inherent to the development of sarcopenia but rather accelerate its progression. In the present review, we discuss how these factors affect systemic and cellular mechanisms that contribute to skeletal muscle atrophy. In addition, we describe gaps in the literature concerning the role of these factors in accelerating sarcopenia progression. Elucidating biochemical pathways related to accelerated muscle atrophy may allow for improved discovery of therapeutic treatments related to sarcopenia.

  20. A novel protocol to accelerate dynamic combinatorial chemistry via isolation of ligand-target adducts from dynamic combinatorial libraries: a case study identifying competitive inhibitors of lysozyme.

    PubMed

    Fang, Zheng; He, Wei; Li, Xin; Li, Zhengjiang; Chen, Beining; Ouyang, Pingkai; Guo, Kai

    2013-09-15

    A novel protocol based on size-exclusion chromatography (SEC) and MS was established to accelerate dynamic combinatorial chemistry (DCC) in this study. By isolating ligand-target adducts from the dynamic combinatorial library (DCL), ligands could be identified directly by MS after denaturation. Three new inhibitors for lysozyme were discovered by this SEC-MS protocol in a case study. Km Data for these new inhibitors was also determined.

  1. Accelerated aging and flashover tests on 138 kV nonceramic line post insulators

    SciTech Connect

    Schneider, H.M.; Guidi, W.W. ); Burnham, J.T. ); Gorur, R.S. ); Hall, J.F. )

    1993-01-01

    The behavior of 138 kV nonceramic line post insulators is investigated by means of clean fog tests conducted before and after aging in a specially designed accelerated aging chamber. The laboratory aging cycles are justified on the basis of actual weather in the coastal regions of Florida. Analytical measurements quantifying the degree of artificial aging are discussed and comparisons of artificial aging with service experience are presented. Observations of audible noise and radio influence voltage during the clean fog tests are reported.

  2. Accelerated epigenetic aging in brain is associated with pre-mortem HIV-associated neurocognitive disorders.

    PubMed

    Levine, Andrew J; Quach, Austin; Moore, David J; Achim, Cristian L; Soontornniyomkij, Virawudh; Masliah, Eliezer; Singer, Elyse J; Gelman, Benjamin; Nemanim, Natasha; Horvath, Steve

    2016-06-01

    HIV infection leads to age-related conditions in relatively young persons. HIV-associated neurocognitive disorders (HAND) are considered among the most prevalent of these conditions. To study the mechanisms underlying this disorder, researchers need an accurate method for measuring biological aging. Here, we apply a recently developed measure of biological aging, based on DNA methylation, to the study of biological aging in HIV+ brains. Retrospective analysis of tissue bank specimens and pre-mortem data was carried out. Fifty-eight HIV+ adults underwent a medical and neurocognitive evaluation within 1 year of death. DNA was obtained from occipital cortex and analyzed with the Illumina Infinium Human Methylation 450K platform. Biological age determined via the epigenetic clock was contrasted with chronological age to obtain a measure of age acceleration, which was then compared between those with HAND and neurocognitively normal individuals. The HAND and neurocognitively normal groups did not differ with regard to demographic, histologic, neuropathologic, or virologic variables. HAND was associated with accelerated aging relative to neurocognitively normal individuals, with average relative acceleration of 3.5 years. Age acceleration did not correlate with pre-mortem neurocognitive functioning or HAND severity. This is the first study to demonstrate that the epigenetic age of occipital cortex samples is associated with HAND status in HIV+ individuals pre-mortem. While these results suggest that the increased risk of a neurocognitive disorder due to HIV might be mediated by an epigenetic aging mechanism, future studies will be needed to validate the findings and dissect causal relationships and downstream effects. PMID:26689571

  3. Senescence-accelerated mouse (SAM): a biogerontological resource in aging research.

    PubMed

    Takeda, T

    1999-01-01

    The senescence-accelerated mouse (SAM), consisting of 14 senescence-prone inbred strains (SAMP) and 4 senescence-resistant inbred strains (SAMR) has been under development since 1970 through the selective inbreeding of AKR/J strain mice donated by the Jackson laboratory in 1968, based on the data of the grading score of senescence, life span, and pathologic phenotypes. The characteristic feature of aging common to all SAMP and SAMR mice is accelerated senescence and normal aging, respectively. Furthermore, SAMP and SAMR strains manifest various pathobiological phenotypes which include such neurobiological phenotypes as deficits in learning and memory, emotional disorders, abnormal circadian rhythms, brain atrophy, hearing impairment, etc., and are often characteristic enough to differentiate the strains. Various efforts are currently being made using the SAM model to clarify the underlying mechanisms in accelerated senescence as well as the etiopathogenic mechanisms in age-associated pathobiologies. Genetic background and significance of SAM development are discussed. PMID:10537019

  4. Effects of fibers on the color change and stability of resin composites after accelerated aging.

    PubMed

    Tuncdemir, Ali Riza; Aykent, Filiz

    2012-01-01

    Composite resins were reinforced with glass and polyethylene fibers in this study, and the effect of fiber reinforcement on the color change of composite resins was investigated. After accelerated aging, the effect of fiber reinforcement on the color stability of composite resins was also examined. There were three experimental groups (n=12 disks per group): non-fiber-reinforced composite (non-FRC control), polyethylene fiber (Ribbond-THM)-reinforced composite, and glass fiber (everstick NET)-reinforced composite. According to the critical remarks of color change of National Bureau of Standarts (NSB), glass fiber-reinforced anterior composites showed trace color change and polyethylene-fiber reinforced composites showed slight color change before accelerated aging. After accelerated aging, both control and fiber-reinforced composite groups showed noticeable color change. It was concluded that both the types of fiber reinforcement and composite resin influenced the color change of fiber-reinforced composite resins.

  5. Accelerated ageing and renal dysfunction links lower socioeconomic status and dietary phosphate intake

    PubMed Central

    McClelland, Ruth; Christensen, Kelly; Mohammed, Suhaib; McGuinness, Dagmara; Cooney, Josephine; Bakshi, Andisheh; Demou, Evangelia; MacDonald, Ewan; Caslake, Muriel; Stenvinkel, Peter; Shiels, Paul G.

    2016-01-01

    Background We have sought to explore the impact of dietary Pi intake on human age related health in the pSoBid cohort (n=666) to explain the disparity between health and deprivation status in this cohort. As hyperphosphataemia is a driver of accelerated ageing in rodent models of progeria we tested whether variation in Pi levels in man associate with measures of biological ageing and health. Results We observed significant relationships between serum Pi levels and markers of biological age (telomere length (p=0.040) and DNA methylation content (p=0.028), gender and chronological age (p=0.032). When analyses were adjusted for socio-economic status and nutritional factors, associations were observed between accelerated biological ageing (telomere length, genomic methylation content) and dietary derived Pi levels among the most deprived males, directly related to the frequency of red meat consumption. Conclusions Accelerated ageing is associated with high serum Pi levels and frequency of red meat consumption. Our data provide evidence for a mechanistic link between high intake of Pi and age-related morbidities tied to socio-economic status. PMID:27132985

  6. Rapid evaluation of the durability of cortical neural implants using accelerated aging with reactive oxygen species

    NASA Astrophysics Data System (ADS)

    Takmakov, Pavel; Ruda, Kiersten; Phillips, K. Scott; Isayeva, Irada S.; Krauthamer, Victor; Welle, Cristin G.

    2015-04-01

    Objective. A challenge for implementing high bandwidth cortical brain-machine interface devices in patients is the limited functional lifespan of implanted recording electrodes. Development of implant technology currently requires extensive non-clinical testing to demonstrate device performance. However, testing the durability of the implants in vivo is time-consuming and expensive. Validated in vitro methodologies may reduce the need for extensive testing in animal models. Approach. Here we describe an in vitro platform for rapid evaluation of implant stability. We designed a reactive accelerated aging (RAA) protocol that employs elevated temperature and reactive oxygen species (ROS) to create a harsh aging environment. Commercially available microelectrode arrays (MEAs) were placed in a solution of hydrogen peroxide at 87 °C for a period of 7 days. We monitored changes to the implants with scanning electron microscopy and broad spectrum electrochemical impedance spectroscopy (1 Hz-1 MHz) and correlated the physical changes with impedance data to identify markers associated with implant failure. Main results. RAA produced a diverse range of effects on the structural integrity and electrochemical properties of electrodes. Temperature and ROS appeared to have different effects on structural elements, with increased temperature causing insulation loss from the electrode microwires, and ROS concentration correlating with tungsten metal dissolution. All array types experienced impedance declines, consistent with published literature showing chronic (>30 days) declines in array impedance in vivo. Impedance change was greatest at frequencies <10 Hz, and smallest at frequencies 1 kHz and above. Though electrode performance is traditionally characterized by impedance at 1 kHz, our results indicate that an impedance change at 1 kHz is not a reliable predictive marker of implant degradation or failure. Significance. ROS, which are known to be present in vivo, can create

  7. Evolution of morphology in UHMWPE following accelerated aging: the effect of heating rates.

    PubMed

    Kurtz, S M; Pruitt, L A; Crane, D J; Edidin, A A

    1999-07-01

    Accelerated aging methods are used to evaluate the oxidative stability of UHMWPE components for total joint replacements. In this study, we traced the evolution of the crystalline morphology during accelerated thermal aging of UHMWPE in air with the intent of explaining previous, counterintuitive heating rate effects. GUR4150HP extruded rod stock material was machined into miniature (0.5 mm thick) specimens that were either gamma irradiated in air or in nitrogen (27 +/- 3 kGy) or left unirradiated (control). Accelerated aging in an air furnace (at 80 degrees C, atmospheric pressure) was performed on half of the test samples at a heating rate of 0.1 degrees C/min and at 5 degrees C/min for the remaining half. Although the initial heating rate, as measured by changes in density, did influence the absolute degradation rate by up to 214%, the heating rate effect did not appear to influence the relative ranking of UHMWPE in terms of its oxidative stability. The heating rate effect is more consistent with a kinetic mechanism of the oxidation process than it is with a previously hypothesized diffusion mechanism. UHMWPE morphology, as characterized using a transmission electron microscope (TEM), demonstrated considerable rearrangement of the crystalline regions as a result of the accelerated aging. The stacking of the lamellae observed after accelerated aging was not consistent with the morphology of naturally aged UHMWPE components. The observed differences in crystalline morphology likely result from the enhanced mobility of the polymer chains due to thermal aging and may be analogous to an annealing process.

  8. Seismic-fragility tests of new and accelerated-aged Class 1E battery cells

    SciTech Connect

    Bonzon, L.L.; Janis, W.J.; Black, D.A.; Paulsen, G.A.

    1987-01-01

    The seismic-fragility response of naturally-aged nuclear station safety-related batteries is of interest for two reasons: (1) to determine actual failure modes and thresholds and (2) to determine the validity of using the electrical capacity of individual cells as an indicator of the potential survivability of a battery given a seismic event. Prior reports in this series discussed the seismic-fragility tests and results for three specific naturally-aged cell types: 12-year old NCX-2250, 10-year old LCU-13, and 10-year old FHC-19. This report focuses on the complementary approach, namely, the seismic-fragility response of accelerated-aged batteries. Of particular interest is the degree to which such approaches accurately reproduce the actual failure modes and thresholds. In these tests the significant aging effects observed, in terms of seismic survivability, were: embrittlement of cell cases, positive bus material and positive plate grids; and excessive sulphation of positive plate active material causing hardening and expansion of positive plates. The IEEE Standard 535 accelerated aging method successfully reproduced seismically significant aging effects in new cells but accelerated grid embrittlement an estimated five years beyond the conditional age of other components.

  9. Multisession Anodal tDCS Protocol Improves Motor System Function in an Aging Population

    PubMed Central

    Dumel, G.; Bourassa, M.-E.; Desjardins, M.; Voarino, N.; Charlebois-Plante, C.; Doyon, J.; De Beaumont, Louis

    2016-01-01

    Objectives. The primary objective of this study was to investigate the effects of five consecutive, daily 20-minute sessions of M1 a-tDCS on motor learning in healthy, cognitively intact, aging adults. Design. A total of 23 participants (51 to 69 years old) performed five consecutive, daily 20-minute sessions of a serial reaction time task (SRT task) concomitant with either anodal (n = 12) or sham (n = 11) M1 a-tDCS. Results. We found a significant group × training sessions interaction, indicating that whereas aging adults in the sham group exhibited little-to-no sequence-specific learning improvements beyond the first day of training, reproducible improvements in the ability to learn new motor sequences over 5 consecutive sessions were the net result in age-equivalent participants from the M1 a-tDCS group. A significant main effect of group on sequence-specific learning revealed greater motor learning for the M1 a-tDCS group when the five learning sessions were averaged. Conclusion. These findings raise into prominence the utility of multisession anodal TDCS protocols in combination with motor training to help prevent/alleviate age-associated motor function decline. PMID:26881118

  10. Towards Accelerated Aging Methodologies and Health Management of Power MOSFETs (Technical Brief)

    NASA Technical Reports Server (NTRS)

    Celaya, Jose R.; Patil, Nishad; Saha, Sankalita; Wysocki, Phil; Goebel, Kai

    2009-01-01

    Understanding aging mechanisms of electronic components is of extreme importance in the aerospace domain where they are part of numerous critical subsystems including avionics. In particular, power MOSFETs are of special interest as they are involved in high voltage switching circuits such as drivers for electrical motors. With increased use of electronics in aircraft control, it becomes more important to understand the degradation of these components in aircraft specific environments. In this paper, we present an accelerated aging methodology for power MOSFETs that subject the devices to indirect thermal overstress during high voltage switching. During this accelerated aging process, two major modes of failure were observed - latch-up and die attach degradation. In this paper we present the details of our aging methodology along with details of experiments and analysis of the results.

  11. Exposure to light at night accelerates aging and spontaneous uterine carcinogenesis in female 129/Sv mice

    PubMed Central

    Popovich, Irina G.; Zabezhinski, Mark A.; Panchenko, Andrei V.; Piskunova, Tatiana S.; Semenchenko, Anna V.; Tyndyk, Maragriata L.; Yurova, Maria N.; Anisimov, Vladimir N.

    2013-01-01

    The effect of the constant illumination on the development of spontaneous tumors in female 129/Sv mice was investigated. Forty-six female 129/Sv mice starting from the age of 2 mo were kept under standard light/dark regimen [12 h light (70 lx):12hr dark; LD, control group], and 46 of 129/Sv mice were kept under constant illumination (24 h a day, 2,500 lx, LL) from the age of 5 mo until to natural death. The exposure to the LL regimen significantly accelerated body weight gain, increased body temperature as well as acceleration of age-related disturbances in estrous function, followed by significant acceleration of the development of the spontaneous uterine tumors in female 129/Sv mice. Total tumor incidence as well as a total number of total or malignant tumors was similar in LL and LD group (p > 0.05). The mice from the LL groups survived less than those from the LD group (χ2 = 8.5; p = 0.00351, log-rank test). According to the estimated parameters of the Cox’s regression model, constant light regimen increased the relative risk of death in female mice compared with the control (LD) group (p = 0.0041). The data demonstrate in the first time that the exposure to constant illumination was followed by the acceleration of aging and spontaneous uterine tumorigenesis in female 129/Sv mice. PMID:23656779

  12. Effect ofartificial accelerated aging on color stability and surface roughness of indirect composites.

    PubMed

    Zanin, Fabíola Rejane; Garcia, Lucas da Fonseca Roberti; Casemiro, Luciana Assirati; Pires-de-Souza, Fernanda de Carvalho Panzeri

    2008-03-01

    Direct and indirect composite resins have different forms of polymerization. Some materials require a post-cure system associating light and heat enhancing clinical properties. This study assessed the changes in color and surface roughness of three indirect composite resins after accelerated aging. Twelve specimens (15 x 2 mm) were obtained for each tested material. Subsequently, the first measurements for roughness tests and colorimetric spectrophotometry (CIE L*a*b* scale) were performed. Specimens were subject to accelerated aging for 384 hours. New measurements were then performed to evaluate the resulting change. Accelerated aging produced color change and increased surface roughness in all composite resins. Solidex resin showed color changes above the clinically accepted value (DeltaE = 4.31 +/- 0.22), and roughness values (Ra = 0.088 +/- 0.008 microm) statistically lower than that of Artglass (Ra = 0.141 +/- 0.026 microm) and Targis (Ra = 0.124 +/- 0.02 microm) (p<0.001). All the indirect resins tested showed color change and increased roughness after accelerated aging. Solidex showed color stability above a quantitative level considered clinically acceptable and lower roughness values compared to the other resins.

  13. Age and gender leucocytes variances and references values generated using the standardized ONE-Study protocol.

    PubMed

    Kverneland, Anders H; Streitz, Mathias; Geissler, Edward; Hutchinson, James; Vogt, Katrin; Boës, David; Niemann, Nadja; Pedersen, Anders Elm; Schlickeiser, Stephan; Sawitzki, Birgit

    2016-06-01

    Flow cytometry is now accepted as an ideal technology to reveal changes in immune cell composition and function. However, it is also an error-prone and variable technology, which makes it difficult to reproduce findings across laboratories. We have recently developed a strategy to standardize whole blood flow cytometry. The performance of our protocols was challenged here by profiling samples from healthy volunteers to reveal age- and gender-dependent differences and to establish a standardized reference cohort for use in clinical trials. Whole blood samples from two different cohorts were analyzed (first cohort: n = 52, second cohort: n = 46, both 20-84 years with equal gender distribution). The second cohort was run as a validation cohort by a different operator. The "ONE Study" panels were applied to analyze expression of >30 different surface markers to enumerate proportional and absolute numbers of >50 leucocyte subsets. Indeed, analysis of the first cohort revealed significant age-dependent changes in subsets e.g. increased activated and differentiated CD4(+) and CD8(+) T cell subsets, acquisition of a memory phenotype for Tregs as well as decreased MDC2 and Marginal Zone B cells. Males and females showed different dynamics in age-dependent T cell activation and differentiation, indicating faster immunosenescence in males. Importantly, although both cohorts consisted of a small sample size, our standardized approach enabled validation of age-dependent changes with the second cohort. Thus, we have proven the utility of our strategy and generated reproducible reference ranges accounting for age- and gender-dependent differences, which are crucial for a better patient monitoring and individualized therapy. © 2016 International Society for Advancement of Cytometry. PMID:27144459

  14. Prediction of brain age suggests accelerated atrophy after traumatic brain injury

    PubMed Central

    Cole, James H; Leech, Robert; Sharp, David J

    2015-01-01

    Objective The long-term effects of traumatic brain injury (TBI) can resemble observed in normal ageing, suggesting that TBI may accelerate the ageing process. We investigate this using a neuroimaging model that predicts brain age in healthy individuals and then apply it to TBI patients. We define individuals' differences in chronological and predicted structural "brain age," and test whether TBI produces progressive atrophy and how this relates to cognitive function. Methods A predictive model of normal ageing was defined using machine learning in 1,537 healthy individuals, based on magnetic resonance imaging–derived estimates of gray matter (GM) and white matter (WM). This ageing model was then applied to test 99 TBI patients and 113 healthy controls to estimate brain age. Results The initial model accurately predicted age in healthy individuals (r * 0.92). TBI brains were estimated to be "older," with a mean predicted age difference (PAD) between chronological and estimated brain age of 4.66 years (±10.8) for GM and 5.97 years (±11.22) for WM. This PAD predicted cognitive impairment and correlated strongly with the time since TBI, indicating that brain tissue loss increases throughout the chronic postinjury phase. Interpretation TBI patients' brains were estimated to be older than their chronological age. This discrepancy increases with time since injury, suggesting that TBI accelerates the rate of brain atrophy. This may be an important factor in the increased susceptibility in TBI patients for dementia and other age-associated conditions, motivating further research into the age-like effects of brain injury and other neurological diseases. PMID:25623048

  15. Compatibility and accelerated aging study for Li(Si)/FeS/sub 2 thermally activated batteries

    NASA Astrophysics Data System (ADS)

    Mead, J. W.; Searcy, J. Q.; Neiswander, P. N.; Poole, R. L.

    1983-12-01

    Thermally activated batteries using the lithium (silicon) iron disulfide (Li(Si)/FeS2) electrochemical system are used in weapons having a required storage life of 25 years and high reliability. A review of known data revealed no information on the compatibility of Li(Si)/FeS2 with the organic materials used in the system. The compatibility question is studied. Accelerated-aging data on pairs of materials were produced. In addition, a group of production batteries was aged and tested. Three aging temperatures were used during the one-year study. Gas analyses, electrical tests and mechanical tests were compared for control and aged samples. Two results, the depletion of oxygen and an increase in hydrogen in the compatibility and accelerated-aging samples, stimulated additional studies. No unexpected or significant changes were observed in the electrical or mechanical properties of the organic materials. Calorific output and chloride ion content of heat pellets indicated no degradation with aging. Ignition sensitivity and burn rate measurements suggested no heat pellet degradation. Oxygen content in aged lithium (silicon) anodes remained within acceptable limits. Single-cell tests and battery test results showed no degradation with aging.

  16. The role of oxidative and nitrosative stress in accelerated aging and major depressive disorder.

    PubMed

    Maurya, Pawan Kumar; Noto, Cristiano; Rizzo, Lucas B; Rios, Adiel C; Nunes, Sandra O V; Barbosa, Décio Sabbatini; Sethi, Sumit; Zeni, Maiara; Mansur, Rodrigo B; Maes, Michael; Brietzke, Elisa

    2016-02-01

    Major depressive disorder (MDD) affects millions of individuals and is highly comorbid with many age associated diseases such as diabetes mellitus, immune-inflammatory dysregulation and cardiovascular diseases. Oxidative/nitrosative stress plays a fundamental role in aging, as well as in the pathogenesis of neurodegenerative/neuropsychiatric disorders including MDD. In this review, we critically review the evidence for an involvement of oxidative/nitrosative stress in acceleration of aging process in MDD. There are evidence of the association between MDD and changes in molecular mechanisms involved in aging. There is a significant association between telomere length, enzymatic antioxidant activities (SOD, CAT, GPx), glutathione (GSH), lipid peroxidation (MDA), nuclear factor κB, inflammatory cytokines with MDD. Major depression also is characterized by significantly lower concentration of antioxidants (zinc, coenzyme Q10, PON1). Since, aging and MDD share a common biological base in their pathophysiology, the potential therapeutic use of antioxidants and anti-aging molecules in MDD could be promising.

  17. Effect of accelerated aging on the microhardness and color stability of flexible resins for dentures.

    PubMed

    Goiato, Marcelo Coelho; Santos, Daniela Micheline dos; Haddad, Marcela Filie; Pesqueira, Aldiéris Alves

    2010-01-01

    Acrylic resins have been widely used due to their acceptable esthetics and desirable characteristics such as easy handling, good thermal conductivity, low permeability to oral fluids and color stability. Flexible resins were introduced on the market as an alternative to the use of conventional acrylic resins in the construction of complete and partial removable dentures. Although these resins present advantages in terms of esthetics and comfort, studies assessing chromatic and microhardness alterations of these materials are still scarce in the related literature. The aim of this study was to evaluate the chromatic and microhardness alterations of two commercial brands of flexible resins in comparison to the conventional resin Triplex when submitted to accelerated aging. The resins were manipulated according to manufacturers' instructions and inserted into a silicone matrix to obtain 21 specimens divided into 3 groups: Triplex, Ppflex and Valplast. Triplex presented the highest microhardness value (p < 0.05) for all the aging periods, which was significantly different from that of the other resins, followed by the values of Valplast and Ppflex. Comparison between the flexible resins (Ppflex and Valplast) revealed a statistically significant difference (p < 0.05) as regards color. The flexible resin Ppflex and the conventional resin Triplex presented no statistically significant difference (p < 0.05) as regards aging. The accelerated aging significantly increased the microhardness values of the resins, with the highest values being observed for Triplex. Valplast presented the greatest chromatic alteration after accelerated aging. PMID:20339724

  18. In vitro cytotoxicity of maxillofacial silicone elastomers: effect of accelerated aging.

    PubMed

    Bal, Bilge Turhan; Yilmaz, Handan; Aydin, Cemal; Karakoca, Seçil; Yilmaz, Sükran

    2009-04-01

    The purpose of this in vitro study was to evaluate the cytotoxicity of three maxillofacial silicone elastomers at 24, 48, and 72 h on L-929 cells and to determine the effect of accelerated aging on the cytotoxicity of these silicone elastomers. Disc-shaped test samples of maxillofacial silicone elastomers (Cosmesil, Episil, Multisil) were fabricated according to manufacturers' instructions under aseptic conditions. Samples were then divided into three groups: (1) not aged; (2) aged for 150 h with an accelerated weathering tester; and (3) aged for 300 h. Then the samples were placed in Dulbecco's Modified Eagle Medium/Ham's F12 (DMEM/F12) for 24, 48, and 72 h. After the incubation periods, cytotoxicity of the extracts to cultured fibroblasts (L-929) was measured by MTT assay. The degree of cytotoxicity of each sample was determined according to the reference value represented by the cells with a control (culture without sample). Statistical significance was determined by repeated measurement ANOVA (p < 0.01) followed by Duncan's test (p < 0.05). All test materials in each group demonstrated high survival rates in MTT assay (Episil; 93.84%, Multisil; 88.30%, Cosmesil; 87.50%, respectively); however, in all groups, Episil material demonstrated significantly higher cell survival rate after each of the experimental incubation periods (p < 0.05). Accelerated aging for 150 and 300 h had no significant effect on the biocompatibility of maxillofacial silicone elastomers tested (p > 0.05).

  19. Evidence of accelerated aging among African Americans and its implications for mortality.

    PubMed

    Levine, M E; Crimmins, E M

    2014-10-01

    Blacks experience morbidity and mortality earlier in the life course compared to whites. Such premature declines in health may be indicative of an acceleration of the aging process. The current study uses data on 7644 black and white participants, ages 30 and above, from the third National Health and Nutrition Examination Survey, to compare the biological ages of blacks and whites as indicated from a combination of ten biomarkers and to determine if such differences in biological age relative to chronological age account for racial disparities in mortality. At a specified chronological age, blacks are approximately 3 years older biologically than whites. Differences in biological age between blacks and whites appear to increase up until ages 60-65 and then decline, presumably due to mortality selection. Finally, differences in biological age were found to completely account for higher levels of all-cause, cardiovascular and cancer mortality among blacks. Overall, these results suggest that being black is associated with significantly higher biological age at a given chronological age and that this is a pathway to early death both overall and from the major age-related diseases.

  20. Acceleration factors for oxidative aging of polymeric materials by oxygen detection.

    SciTech Connect

    Assink, Roger Alan; Celina, Mathias Christopher; Skutnik, Julie Michelle

    2005-01-01

    Three methods that were used to measure the chemical changes associated with oxidative degradation of polymeric materials are presented. The first method is based on the nuclear activation of {sup 18}O in an elastomer that was thermally aged in an {sup 18}O{sub 2} atmosphere. Second, the alcohol groups in a thermally aged elastomer were derivatized with trifluoroacetic anhydride and their concentration measured via {sup 19}F NMR spectroscopy. Finally, a respirometer was used to directly measure the oxidative rates of a polyurethane foam as a function of aging temperature. The measurement of the oxidation rates enabled acceleration factors for oxidative degradation of these materials to be calculated.

  1. [Anti-aging studies on the senescence accelerated mouse (SAM) strains].

    PubMed

    Takahashi, Ryoya

    2010-01-01

    Senescence accelerated mouse (SAM), a murine model of accelerated senescence, was established by Toshio Takeda and colleagues. SAM consists of series of SAMP (prone) and SAMR (resistant) lines. All SAMP lines (from SAMP1 to SAMP11) are characterized by accelerated accumulation of senile features, earlier onset and faster progress of age-associated pathological phenotypes, such as amyloidosis, impaired immune response, senile osteoporosis and deficits in learning and memory. These SAMP lines are useful for evaluation of putative anti-aging therapies. For example, SAMP1 line is used to study the anti-aging effect of the antioxidant containing foods and various anti-oxidants, such as coenzyme Q10, vitamin C, lycopene. SAMP8 line exhibiting an early onset of impaired learning and memory is often used for test strategies for therapeutic intervention of dementia of early onset. SAMP6 is used as an animal model for developing new strategies for the treatment of osteoporosis in humans. Various lines of SAM (P1, P6, P8, P10 and R1) are now commercially available for research. In this review, I will briefly introduce various usages of SAM in anti-aging research. PMID:20046059

  2. Gamma radiation and magnetic field mediated delay in effect of accelerated ageing of soybean.

    PubMed

    Kumar, Mahesh; Singh, Bhupinder; Ahuja, Sumedha; Dahuja, Anil; Anand, Anjali

    2015-08-01

    Soybean seeds were exposed to gamma radiation (0.5, 1, 3 and 5 kGy), static magnetic field (50, 100 and 200 mT) and a combination of gamma radiation and magnetic energy (0.5 kGy + 200 mT and 5 kGy + 50 mT) and stored at room temperature for six months. These seeds were later subjected to accelerated ageing treatment at 42 °C temperature and 95-100 % relative humidity and were compared for various physical and biochemical characteristics between the untreated and the energized treatments. Energy treatment protected the quality of stored seeds in terms of its protein and oil content . Accelerated aging conditions, however, affected the oil and protein quantity and quality of seed negatively. Antioxidant enzymes exhibited a decline in their activity during aging while the LOX activity, which reflects the rate of lipid peroxidation, in general, increased during the aging. Gamma irradiated (3 and 5 kGy) and magnetic field treated seeds (100 and 200 mT) maintained a higher catalase and ascorbate peroxidase activity which may help in efficient scavenging of deleterious free radical produced during the aging. Aging caused peroxidative changes to lipids, which could be contributed to the loss of oil quality. Among the electromagnetic energy treatments, a dose of 1-5 kGy of gamma and 100 mT, 200 mT magnetic field effectively slowed the rate of biochemical degradation and loss of cellular integrity in seeds stored under conditions of accelerated aging and thus, protected the deterioration of seed quality. Energy combination treatments did not yield any additional protection advantage. PMID:26243899

  3. Colour stability of temporary restorations with different thicknesses submitted to artificial accelerated aging.

    PubMed

    Silame, F D J; Tonani, R; Alandia-Roman, C C; Chinelatti, M; Panzeri, H; Pires-de-Souza, F C P

    2013-12-01

    This study evaluated the colour stability of temporary prosthetic restorations with different thicknesses submitted to artificial accelerated aging. The occlusal surfaces of 40 molars were grinded to obtain flat enamel surfaces. Twenty acrylic resin specimens [Polymethyl methacrylate (Duralay) and Bis-methyl acrylate (Luxatemp)] were made with two different thicknesses, 0.5 mm and 1.0 mm. Temporary restorations were fixed on enamel and CIE L*a*b* colour parameters of each specimen were assessed before and after artificial accelerated aging. All groups showed colour alterations above the clinically acceptable limit. Luxatemp showed the lowest colour alteration regardless its thickness and Duralay showed the greatest alteration with 0.5 mm. PMID:24479216

  4. Circadian disruption induced by light-at-night accelerates aging and promotes tumorigenesis in rats

    PubMed Central

    Vinogradova, Irina A.; Anisimov, Vladimir N.; Bukalev, Andrey V.; Semenchenko, Anna V.; Zabezhinski, Mark A.

    2009-01-01

    We evaluated the effect of various light/dark regimens on the survival, life span and tumorigenesis in rats. Two hundred eight male and 203 females LIO rats were subdivided into 4 groups and kept at various light/dark regimens: standard 12:12 light/dark (LD); natural lighting of the North-West of Russia (NL); constant light (LL), and constant darkness (DD) since the age of 25 days until natural death. We found that exposure to NL and LL regimens accelerated development of metabolic syndrome and spontaneous tumorigenesis, shortened life span both in male and females rats as compared to the standard LD regimen. We conclude that circadian disruption induced by light-at-night accelerates aging and promotes tumorigenesis in rats. This observation supports the conclusion of the International Agency Research on Cancer that shift-work that involves circadian disruption is probably carcinogenic to humans. PMID:20157558

  5. Colour stability of temporary restorations with different thicknesses submitted to artificial accelerated aging.

    PubMed

    Silame, F D J; Tonani, R; Alandia-Roman, C C; Chinelatti, M; Panzeri, H; Pires-de-Souza, F C P

    2013-12-01

    This study evaluated the colour stability of temporary prosthetic restorations with different thicknesses submitted to artificial accelerated aging. The occlusal surfaces of 40 molars were grinded to obtain flat enamel surfaces. Twenty acrylic resin specimens [Polymethyl methacrylate (Duralay) and Bis-methyl acrylate (Luxatemp)] were made with two different thicknesses, 0.5 mm and 1.0 mm. Temporary restorations were fixed on enamel and CIE L*a*b* colour parameters of each specimen were assessed before and after artificial accelerated aging. All groups showed colour alterations above the clinically acceptable limit. Luxatemp showed the lowest colour alteration regardless its thickness and Duralay showed the greatest alteration with 0.5 mm.

  6. Correlating outdoor exposure with accelerated aging tests for aluminum solar reflectors

    NASA Astrophysics Data System (ADS)

    Wette, Johannes; Sutter, Florian; Fernández-García, Aránzazu

    2016-05-01

    Guaranteeing the durability of concentrated solar power (CSP) components is crucial for the success of the technology. The reflectors of the solar field are a key component of CSP plants, requiring reliable methods for service lifetime prediction. So far, no proven correlations exist to relate accelerated aging test results in climate chambers with relevant CSP exposure sites. In this work, correlations have been derived for selected testing conditions that excite the same degradation mechanisms as for outdoor exposure. Those testing conditions have been identified by performing an extensive microscopic comparison of the appearing degradation mechanisms on reference samples that have been weathered outdoors with samples that underwent a high variety of accelerated aging experiments. The herein developed methodology is derived for aluminum reflectors and future work will study its applicability to silvered-glass mirrors.

  7. Fractography evolution in accelerated aging of UHMWPE after gamma irradiation in air.

    PubMed

    Medel, F; Gómez-Barrena, E; García-Alvarez, F; Ríos, R; Gracia-Villa, L; Puértolas, J A

    2004-01-01

    We studied the fracture surface evolution of ultra high molecular weight polyethylene (UHMWPE) specimens, manufactured from GUR 1050 compression moulded sheets, after gamma sterilisation in air followed by different aging times after thermal treatment at 120 degrees C. Degradation profiles were obtained by FTIR and DSC measurements after 0, 7, 14, 24 and 36h aging. We observed by SEM the morphology patterns at these aging times, in surface fractographies after uniaxial tensile test of standardised samples. The results pointed out clear differences between short and long aging times. At shorter times, 7h, the behaviour was similar to non-degraded UHMWPE, exhibiting ductile behaviour. At longer times, 24-36h, this thermal protocol provided a highly degraded zone in the subsurface, similar to the white band found after gamma irradiation in air followed by natural aging, although closer to the surface, at 150-200mum. The microstructure of this oxidation zone, similarly found in gamma irradiated samples shelf-aged for 6-7 years, although with different distribution of microvoids, was formed by fibrils, associated with embrittlement of the oxidised UHMWPE. In addition, the evolution of the oxidation index, the enthalpy content, the mechanical parameters, and the depth of the oxidation front deduced from the fractographies versus aging time showed that a changing behaviour in the degradation rate appeared at intermediate aging times.

  8. Dynamic changes of DNA epigenetic marks in mouse oocytes during natural and accelerated aging.

    PubMed

    Qian, Yan; Tu, Jiajie; Tang, Nelson Leung Sang; Kong, Grace Wing Shan; Chung, Jacqueline Pui Wah; Chan, Wai-Yee; Lee, Tin-Lap

    2015-10-01

    Aging is a complex time-dependent biological process that takes place in every cell and organ, eventually leading to degenerative changes that affect normal biological functions. In the past decades, the number of older parents has increased significantly. While it is widely recognized that oocyte aging poses higher birth and reproductive risk, the exact molecular mechanisms remain largely elusive. DNA methylation of 5-cytosine (5mC) and histone modifications are among the key epigenetic mechanisms involved in critical developmental processes and have been linked to aging. However, the impact of oocyte aging on DNA demethylation pathways has not been examined. The recent discovery of Ten-Eleven-Translocation (TET) family proteins, thymine DNA glycosylase (TDG) and the demethylation intermediates 5hmC, 5fC and 5caC has provided novel clues to delineate the molecular mechanisms in DNA demethylation. In this study, we examined the cellular level of modified cytosines (5mC, 5hmC, 5fC and 5caC) and Tet/Tdg expression in oocytes obtained from natural and accelerated oocyte aging conditions. Here we show all the DNA demethylation marks are dynamically regulated in both aging conditions, which are associated with Tet3 over-expression and Tdg repression. Such an aberrant expression pattern was more profound in accelerated aging condition. The results suggest that DNA demethylation may be actively involved in oocyte aging and have implications for development of potential drug targets to rejuvenate aging oocytes. This article is part of a Directed Issue entitled: Epigenetics dynamics in development and disease.

  9. Does cyclic stress and accelerated ageing influence the wear behavior of highly crosslinked polyethylene?

    PubMed

    Affatato, Saverio; De Mattia, Jonathan Salvatore; Bracco, Pierangiola; Pavoni, Eleonora; Taddei, Paola

    2016-06-01

    First-generation (irradiated and remelted or annealed) and second-generation (irradiated and vitamin E blended or doped) highly crosslinked polyethylenes were introduced in the last decade to solve the problems of wear and osteolysis. In this study, the influence of the Vitamin-E addition on crosslinked polyethylene (XLPE_VE) was evaluated by comparing the in vitro wear behavior of crosslinked polyethylene (XLPE) versus Vitamin-E blended polyethylene XLPE and conventional ultra-high molecular weight polyethylene (STD_PE) acetabular cups, after accelerated ageing according to ASTM F2003-02 (70.0±0.1°C, pure oxygen at 5bar for 14 days). The test was performed using a hip joint simulator run for two millions cycles, under bovine calf serum as lubricant. Mass loss was found to decrease along the series XLPE_VE>STD_PE>XLPE, although no statistically significant differences were found between the mass losses of the three sets of cups. Micro-Raman spectroscopy was used to investigate at a molecular level the morphology changes induced by wear. The spectroscopic analyses showed that the accelerated ageing determined different wear mechanisms and molecular rearrangements during testing with regards to the changes in both the chain orientation and the distribution of the all-trans sequences within the orthorhombic, amorphous and third phases. The results of the present study showed that the addition of vitamin E was not effective to improve the gravimetric wear of PE after accelerated ageing. However, from a molecular point of view, the XLPE_VE acetabular cups tested after accelerated ageing appeared definitely less damaged than the STD_PE ones and comparable to XLPE samples. PMID:26970299

  10. On the Use of Accelerated Aging Methods for Screening High Temperature Polymeric Composite Materials

    NASA Technical Reports Server (NTRS)

    Gates, Thomas S.; Grayson, Michael A.

    1999-01-01

    A rational approach to the problem of accelerated testing of high temperature polymeric composites is discussed. The methods provided are considered tools useful in the screening of new materials systems for long-term application to extreme environments that include elevated temperature, moisture, oxygen, and mechanical load. The need for reproducible mechanisms, indicator properties, and real-time data are outlined as well as the methodologies for specific aging mechanisms.

  11. Declining expression of a single epithelial cell-autonomous gene accelerates age-related thymic involution

    PubMed Central

    Sun, Liguang; Guo, Jianfei; Brown, Robert; Amagai, Takashi; Zhao, Yong; Su, Dong-Ming

    2010-01-01

    SUMMARY Age-related thymic involution may be triggered by gene expression changes in lymphohematopoietic and/or non-hematopoietic thymic epithelial cells (TECs). The role of epithelial cell-autonomous gene FoxN1 may be involved in the process, but it is still a puzzle due to shortage of evidence from gradual loss-of-function and exogenous gain-of-function studies. Using our recently generated loxP-floxed-FoxN1(fx) mouse carrying the ubiquitous CreERT (uCreERT) transgene with a low dose of spontaneous activation, which causes gradual FoxN1 deletion with age, we found that the uCreERT-fx/fx mice showed an accelerated age-related thymic involution due to progressive loss of FoxN1+ TECs. The thymic aging phenotypes were clearly observable as early as at 3–6 months of age, resembling the naturally aged (18–22-month-old) murine thymus. By intrathymically supplying aged wild-type mice with exogenous FoxN1-cDNA, thymic involution and defective peripheral CD4+ T-cell function could be partially rescued. The results support the notion that decline of a single epithelial cell-autonomous gene FoxN1 levels with age causes primary deterioration in TECs followed by impairment of the total postnatal thymic microenvironment, and potentially triggers age-related thymic involution in mice. PMID:20156205

  12. Short versus Long Gonadotropin-Releasing Hormone Analogue Suppression Protocols in IVF/ICSI Cycles in Patients of Various Age Ranges

    PubMed Central

    Li, Yubin; Xu, Yanwen; Zhou, Canquan

    2015-01-01

    Objective To compare the two GnRH-a protocols (long GnRH-a protocol and short GnRH-a protocol) for ovarian stimulation in IVF/ICSI cycles in patients of various age ranges. Methods A total of 5662 IVF-ET/ICSI cycles from 2010 to 2013 were retrospectively identified. The cycles were divided into two groups: a long protocol group and short protocol group. In each group, the patients were divided into four age ranges: <31 years, 31 to 35 years, 36 to 40 years, and >40 years. The duration of stimulation, total dose of Gn, implantation rate and pregnancy rate were compared. Results The total dose of Gn was significantly higher, and the duration of stimulation was significantly longer, in the long protocol group than in the short protocol group for all age ranges (P<0.05). If the patients were of the same age range, the number of oocytes retrieved, MII oocytes, and high-quality embryos in the long protocol group were all significantly greater than those in the short protocol group (P<0.05). In the long protocol group, the clinical pregnancy rates of the four age ranges were 52.76%, 44.33%, 36.15% and 13.33%, respectively, which were significantly higher than those in the short protocol group (33.33%, 24.58%, 22.49% and 8.72%, respectively; P<0.05). The same trend was also found in the implantation rates of the four age ranges. As the age increased, the clinical pregnancy and implantation rates, as well as the number of oocytes retrieved, MII oocytes, and high-quality embryos, of the long protocol group significantly decreased (P<0.05). Conclusions Our study demonstrated that regardless of patient age, the long protocol was superior to the short protocol in terms of the number of retrieved oocytes, as well as the implantation and pregnancy rates. PMID:26208150

  13. Sod2 haploinsufficiency does not accelerate aging of telomere dysfunctional mice.

    PubMed

    Guachalla, Luis Miguel; Ju, Zhenyu; Koziel, Rafal; von Figura, Guido; Song, Zhangfa; Fusser, Markus; Epe, Bernd; Jansen-Durr, Pidder; Rudolph, K Lenhard

    2009-03-05

    Telomere shortening represents a causal factor of cellular senescence. At the same time, several lines of evidence indicate a pivotal role of oxidative DNA damage for the aging process in vivo. A causal connection between the two observations was suggested by experiments showing accelerated telomere shorting under conditions of oxidative stress in cultured cells, but has never been studied in vivo. We therefore have analysed whether an increase in mitochondrial derived oxidative stress in response to heterozygous deletion of superoxide dismutase (Sod2(+/-)) would exacerbate aging phenotypes in telomere dysfunctional (mTerc(-/-)) mice. Heterozygous deletion of Sod2 resulted in reduced SOD2 protein levels and increased oxidative stress in aging telomere dysfunctional mice, but this did not lead to an increase in basal levels of oxidative nuclear DNA damage, an accumulation of nuclear DNA breaks, or an increased rate of telomere shortening in the mice. Moreover, heterozygous deletion of Sod2 did not accelerate the depletion of stem cells and the impairment in organ maintenance in aging mTerc(-/-) mice. In agreement with these observations, Sod2 haploinsufficiency did not lead to a further reduction in lifespan of mTerc(-/-) mice. Together, these results indicate that a decrease in SOD2-dependent antioxidant defence does not exacerbate aging in the context of telomere dysfunction.

  14. Proposition of an Accelerated Ageing Method for Natural Fibre/Polylactic Acid Composite

    NASA Astrophysics Data System (ADS)

    Zandvliet, Clio; Bandyopadhyay, N. R.; Ray, Dipa

    2015-10-01

    Natural fibre composite based on polylactic acid (PLA) composite is of special interest because it is entirely from renewable resources and biodegradable. Some samples of jute/PLA composite and PLA alone made 6 years ago and kept in tropical climate on a shelf shows too fast ageing degradation. In this work, an accelerated ageing method for natural fibres/PLA composite is proposed and tested. Experiment was carried out with jute and flax fibre/PLA composite. The method was compared with the standard ISO 1037-06a. The residual flexural strength after ageing test was compared with the one of common wood-based panels and of real aged samples prepared 6 years ago.

  15. Monitoring migration and transformation of nanomaterials in polymeric composites during accelerated aging

    NASA Astrophysics Data System (ADS)

    Vilar, G.; Fernández-Rosas, E.; Puntes, V.; Jamier, V.; Aubouy, L.; Vázquez-Campos, S.

    2013-04-01

    The incorporation of small amounts of nanoadditives in polymeric compounds can introduce new mechanical, physical, electrical, magnetic, thermal and/or optical properties. The properties of these advanced materials have enabled new applications in several industrial sectors (electronics, automotive, textile...). In particular, for the nanomaterials (NM) described in this work, multi-walled carbon nanotubes (MWCNT) and silicon dioxide nanoparticles (SiO2 NP), the following properties have been described: MWCNT act as nucleating agents in thermoplastics, and change viscosity, affecting dispersion, orientation, and therefore mechanical, thermal, and electrical properties; and SiO2 NP act as flame retardant and display improved electrical and mechanical properties. The work described here is focused on the evaluation of the migration and transformation of NM included in polymer nanocomposites (NC) during accelerated climatic ageing. To this aim, we generated polyamide 6 (PA6) NC with different degree of compatibility between the NM and the polymeric matrix. These NC were submitted to accelerated aging conditions to simulate outdoor conditions (simulation of the use phase of the polymeric NC). The NC contain as nanofillers MWCNT and SiO2 NP with different surface properties to influence the compatibility with the polymeric matrix. The generated NC were evaluated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) with Energy-dispersive X-ray spectroscopy (EDX), thermogravimetry (TGA) and differential scanning calorimetry (DSC) before and after the aging process, to monitor the compatibility of the NM with the matrix: dispersion within the matrix, migration during aging, and modification of the polymer properties. The dispersion of SiO2 NP in the NC depended on their compatibility with the matrix. However, independently of their compatibility with the matrix, SiO2 NP were aggregated at the end of the accelerated aging process. In addition

  16. Accelerated changes in white matter microstructure during aging: a longitudinal diffusion tensor imaging study.

    PubMed

    Sexton, Claire E; Walhovd, Kristine B; Storsve, Andreas B; Tamnes, Christian K; Westlye, Lars T; Johansen-Berg, Heidi; Fjell, Anders M

    2014-11-12

    It is well established that human brain white matter structure changes with aging, but the timescale and spatial distribution of this change remain uncertain. Cross-sectional diffusion tensor imaging (DTI) studies indicate that, after a period of relative stability during adulthood, there is an accelerated decline in anisotropy and increase in diffusivity values during senescence; and, spatially, results have been discussed within the context of several anatomical frameworks. However, inferring trajectories of change from cross-sectional data can be challenging; and, as yet, there have been no longitudinal reports of the timescale and spatial distribution of age-related white matter change in healthy adults across the adult lifespan. In a longitudinal DTI study of 203 adults between 20 and 84 years of age, we used tract-based spatial statistics to characterize the pattern of annual change in fractional anisotropy, axial diffusivity, radial diffusivity, and mean diffusivity and examined whether there was an acceleration of change with age. We found extensive and overlapping significant annual decreases in fractional anisotropy, and increases in axial diffusivity, radial diffusivity, and mean diffusivity. Spatially, results were consistent with inferior-to-superior gradients of lesser-to-greater vulnerability. Annual change increased with age, particularly within superior regions, with age-related decline estimated to begin in the fifth decade. Charting white matter microstructural changes in healthy aging provides essential context to clinical studies, and future studies should compare age trajectories between healthy participants and at-risk populations and also explore the relationship between DTI rates of change and cognitive decline.

  17. Tooth loss early in life accelerates age-related bone deterioration in mice.

    PubMed

    Kurahashi, Minori; Kondo, Hiroko; Iinuma, Mitsuo; Tamura, Yasuo; Chen, Huayue; Kubo, Kin-ya

    2015-01-01

    Both osteoporosis and tooth loss are health concerns that affect many older people. Osteoporosis is a common skeletal disease of the elderly, characterized by low bone mass and microstructural deterioration of bone tissue. Chronic mild stress is a risk factor for osteoporosis. Many studies showed that tooth loss induced neurological alterations through activation of a stress hormone, corticosterone, in mice. In this study, we tested the hypothesis that tooth loss early in life may accelerate age-related bone deterioration using a mouse model. Male senescence-accelerated mouse strain P8 (SAMP8) mice were randomly divided into control and toothless groups. Removal of the upper molar teeth was performed at one month of age. Bone response was evaluated at 2, 5 and 9 months of age. Tooth loss early in life caused a significant increase in circulating corticosterone level with age. Osteoblast bone formation was suppressed and osteoclast bone resorption was activated in the toothless mice. Trabecular bone volume fraction of the vertebra and femur was decreased in the toothless mice with age. The bone quality was reduced in the toothless mice at 5 and 9 months of age, compared with the age-matched control mice. These findings indicate that tooth loss early in life impairs the dynamic homeostasis of the bone formation and bone resorption, leading to reduced bone strength with age. Long-term tooth loss may have a cumulative detrimental effect on bone health. It is important to take appropriate measures to treat tooth loss in older people for preventing and/or treating senile osteoporosis.

  18. Lamin Mutations Accelerate Aging via Defective Export of Mitochondrial mRNAs through Nuclear Envelope Budding.

    PubMed

    Li, Yihang; Hassinger, Linda; Thomson, Travis; Ding, Baojin; Ashley, James; Hassinger, William; Budnik, Vivian

    2016-08-01

    Defective RNA metabolism and transport are implicated in aging and degeneration [1, 2], but the underlying mechanisms remain poorly understood. A prevalent feature of aging is mitochondrial deterioration [3]. Here, we link a novel mechanism for RNA export through nuclear envelope (NE) budding [4, 5] that requires A-type lamin, an inner nuclear membrane-associated protein, to accelerated aging observed in Drosophila LaminC (LamC) mutations. These LamC mutations were modeled after A-lamin (LMNA) mutations causing progeroid syndromes (PSs) in humans. We identified mitochondrial assembly regulatory factor (Marf), a mitochondrial fusion factor (mitofusin), as well as other transcripts required for mitochondrial integrity and function, in a screen for RNAs that exit the nucleus through NE budding. PS-modeled LamC mutations induced premature aging in adult flight muscles, including decreased levels of specific mitochondrial protein transcripts (RNA) and progressive mitochondrial degradation. PS-modeled LamC mutations also induced the accelerated appearance of other phenotypes associated with aging, including a progressive accumulation of polyubiquitin aggregates [6, 7] and myofibril disorganization [8, 9]. Consistent with these observations, the mutants had progressive jumping and flight defects. Downregulating marf alone induced the above aging defects. Nevertheless, restoring marf was insufficient for rescuing the aging phenotypes in PS-modeled LamC mutations, as other mitochondrial RNAs are affected by inhibition of NE budding. Analysis of NE budding in dominant and recessive PS-modeled LamC mutations suggests a mechanism by which abnormal lamina organization prevents the egress of these RNAs via NE budding. These studies connect defects in RNA export through NE budding to progressive loss of mitochondrial integrity and premature aging. PMID:27451905

  19. The influence of the accelerated ageing on the black screen element of the Electroink prints

    NASA Astrophysics Data System (ADS)

    Majnaric, I.; Bolanca, Z.; Bolanca Mirkovic, I.

    2010-06-01

    Printing material and prints undergo changes during ageing which can be recognized in deterioration in the physical, chemical and optical properties. The aim of this work is to determine the optical changes of the prints caused by ageing of the printing material and of the prints obtained by the application of the indirect electrophotography. The change of the screen elements in lighter halftone areas, which was obtained by the usage of the microscopic image analysis, has been discussed in the article. For the preparation of samples the following papers were used: fine art paper, recycled paper and offset paper as well as black Electroink. Three sample series were observed: prints on nonaged paper and ElectroInk, prints on aged paper and ElectroInk and prints on aged paper and nonaged ElectroInk. The investigation results show that by ageing of the uncoated printing substrates the decrease of the dots on prints can be expected, while the printing on the aged paper results in the increased reproduction of the halftone dots. The obtained results are the contribution to the explanation of the influence of the accelerated ageing process of papers which are used for printing and the aged prints on the halftone dot changes. Except the mentioned determined scientific contribution the results are applicable in the area of the printing product quality as well as in the forensic science.

  20. "Accelerating aging" chemotherapy on aged animals: protective effect from nutraceutical modulation.

    PubMed

    Marotta, Francesco; Harada, Masatoshi; Minelli, Emilio; Ono-Nita, Suzanne K; Marandola, Paulo

    2008-04-01

    The aim of this study was to test a novel phytocompound in an experimental model of antitumor-induced immunosuppression. Five groups of mice were considered: young (Y) and aged (A) that were given intraperitoneally 10 doses of cyclophosphamide (CPX, 25mg/kg/bw) or CPX plus (150 mg/kg/bw) of the nutraceutical DTS (Denshichi-Tochiu-Sen), and control. After sacrifice, macrophage chemotaxis and serum levels of IFN-gamma, IL-2, and GM-CSF were determined. Liver and urinary bladder were examined histologically, as were the liver and kidney for redox enzymes. CPX significantly decreased macrophage chemotaxis and all cytokines (p < 0.05, A > Y). DTS restored macrophage function and cytokine concentration (p < 0.001) and partly improved the necro-inflammatory score and substance P receptor expression in the bladder and the redox status in liver and kidney (p < 0.05). Such data suggest that DTS effectively prevents CPX-induced immune suppression and oxidative-inflammatory damage, which are particularly enhanced in aged organisms.

  1. Effect of energy density on color stability in dental resin composites under accelerated aging.

    PubMed

    Zamarripa, Eliezer; Ancona, Adriana L; D'Accorso, Norma B; Macchi, Ricardo L; Abate, Pablo F

    2008-01-01

    The effects of the energy density that is used for polymerization on properties of dental resin composites are well known. However, few studies relate color stability to this factor. The aim of this study was to assess color changes (deltaE*), in vitro, in terms of accelerated aging under UV exposure of specimens prepared with different energy densities. Four commercial dental resin composites were included in the study. Thirty six specimens were prepared for each one of them, following the procedure established by ISO 4049 Standard, and assigned to three groups: A (3.75 J/cm2), B (9 J/cm2), C (24 J/cm2). Each group was further subdivided into four subgroups: 1 (no aging), 2 (500 hours aging), 3 (1000 hours aging) and 4 (1500 hours aging). The results were analyzed by means of ANOVA and Tukey's test (alpha = 0.05) to determine the effect of the factors. Correlation was performed in order to determine the possible relationship among variables. Energy density is not a significant factor in color stability. However aging is directly proportional to color changes. deltaE* depends on filler size; hybrid material presented deltaE* of 2.1(0.5), 2.4(0.6) and 3.3(0.3) at 500, 1000 and 1500 hours of accelerated aging respectively, and nanofilled material showed deltaE* of 3.0(0.6), 4.5(1.2) and 5.9(0.6) at the same times respectively. It can be concluded that deltaE* does not depend on energy density; however other factors are involved in color change. Further studies in this area are warranted.

  2. Accelerated long-term forgetting in aging and intra-sleep awakenings

    PubMed Central

    Mary, Alison; Schreiner, Svenia; Peigneux, Philippe

    2013-01-01

    The architecture of sleep and the functional neuroanatomical networks subtending memory consolidation processes are both modified with aging, possibly leading to accelerated forgetting in long-term memory. We investigated associative learning and declarative memory consolidation processes in 16 young (18–30 years) and 16 older (65–75 years) healthy adults. Performance was tested using a cued recall procedure at the end of learning (immediate recall), and 30 min and 7 days later. A delayed recognition test was also administered on day 7. Daily sleep diaries were completed during the entire experiment. Results revealed a similar percentage of correct responses at immediate and 30-min recall in young and older participants. However, recall was significantly decreased 7 days later, with an increased forgetting in older participants. Additionally, intra-sleep awakenings were more frequent in older participants than young adults during the seven nights, and were negatively correlated with delayed recall performance on day 7 in the older group. Altogether, our results suggest a decline in verbal declarative memory consolidation processes with aging, eventually leading to accelerated long-term forgetting indicating that increased sleep fragmentation due to more frequent intra-sleep awakenings in older participants contribute to the reported age-related decline in long-term memory retrieval. Our results highlight the sensitivity of long-term forgetting measures to evidence consolidation deficits in healthy aging. PMID:24137151

  3. Effects of different polishing methods on color stability of resin composites after accelerated aging.

    PubMed

    Sirin Karaarslan, Emine; Bulbul, Mehmet; Yildiz, Esma; Secilmis, Asli; Sari, Fatih; Usumez, Aslihan

    2013-01-01

    The purpose of this study was to evaluate the effect of polishing procedures on the color stability of different types of composites after aging. Forty disk-shaped specimens (Ø10×2 mm) were prepared for each composite resin type (an ormocer, a packable, a nanohybrid, and a microhybrid) for a total of 160 specimens. Each composite group was divided into four subgroups according to polishing method (n=10): control (no finishing and polishing), polishing disk, polishing wheel, and glaze material. Color parameters (L*, a*, and b*) and surface roughness were measured before and after accelerated aging. Of the polishing methods, glazed specimens showed the lowest color change (∆E*), ∆L*, and ∆b* values (p<0.05). Of the composite resins, the microhybrid composite showed the lowest ∆E* value, whereas the ormocer showed the highest (p<0.05). For all composite types, the surface roughness of their control groups decreased after aging (p<0.05). In conclusion, all composite resins showed color changes after accelerated aging, with the use of glaze material resulting in the lowest color change.

  4. Hardness evaluation of prosthetic silicones containing opacifiers following chemical disinfection and accelerated aging.

    PubMed

    Goiato, Marcelo Coelho; Haddad, Marcela Filié; Santos, Daniela Micheline dos; Pesqueira, Aldiéris Alves; Moreno, Amália

    2010-01-01

    We evaluated the effects of disinfection and aging on the hardness of silicones containing opacifiers and intended for use in facial prosthetics. A total of 90 samples were produced using a cylindrical metal mold 3 mm in height and 30 mm in diameter. The samples were fabricated from Silastic MDX 4-4210 silicone in three groups: GI contained no opacifier, GII contained barium sulfate (Ba), and GIII contained titanium dioxide (Ti). The samples were disinfected using effervescent tablets (Ef), neutral soap (Ns), or 4% chlorhexidine (Cl) 3 times a week for 60 days. After this period the samples underwent 1,008 hours of accelerated aging. The hardness was measured using a durometer immediately following the disinfection period and after 252, 504, and 1,008 hours of aging. The data were statistically analyzed using 3-way ANOVA and the Tukey test (p < .05). The GIII group exhibited the greatest variation in hardness regardless of elapsed time. All groups displayed greater hardness after 1,008 hours of accelerated aging independent of disinfectant type. All of the hardness values were within the clinically acceptable range.

  5. Dicarbonyl-induced accelerated aging in vitro in human skin fibroblasts.

    PubMed

    Sejersen, Henrik; Rattan, Suresh I S

    2009-04-01

    Dicarbonyls glyoxal (GO) and methylglyoxal (MGO) produced during the autoxidation of reducing sugars are a source of macromolecular damage in cells. Since an accumulation of damaged macromolecules is a universal characteristic of aging, we have tested whether GO and MGO which cause oxidative damage to proteins and other macromolecules can bring about accelerated aging in normal human skin fibroblasts in vitro. A treatment of cells with 1.0 mM GO or 400 microM MGO leads to the appearance of senescent phenotype within 3 days, as judged by the following criteria: morphological phenotype, irreversible growth arrest and G2 arrest, increased senescence-associated beta-galactosidase (SABG) activity, increased H2O2 level, increased Nxi-(carboxymethyl)-lysine (CML) protein level, and altered activities of superoxide dismutase and catalase antioxidant enzymes. This experimental model of accelerated cellular aging in vitro can be useful for studies on testing the effects of various physical, chemical and biological conditions, including natural and synthetic molecules, for the modulation of aging.

  6. The longitudinal urban cohort ageing study (LUCAS): study protocol and participation in the first decade

    PubMed Central

    2012-01-01

    Background We present concept, study protocol and selected baseline data of the Longitudinal Urban Cohort Ageing Study (LUCAS) in Germany. LUCAS is a long-running cohort study of community-dwelling seniors complemented by specific studies of geriatric patients or diseases. Aims were to (1) Describe individual ageing trajectories in a metropolitan setting, documenting changes in functional status, the onset of frailty, disability and need of care; (2) Find determinants of healthy ageing; (3) Assess long-term effects of specific health promotion interventions; (4) Produce results for health care planning for fit, pre-frail, frail and disabled elderly persons; (5) Set up a framework for embedded studies to investigate various hypotheses in specific subgroups of elderly. Methods/Design In 2000, twenty-one general practitioners (GPs) were recruited in the Hamburg metropolitan area; they generated lists of all their patients 60 years and older. Persons not terminally ill, without daily need of assistance or professional care were eligible. Of these, n = 3,326 (48 %) agreed to participate and completed a small (baseline) and an extensive health questionnaire (wave 1). In 2007/2008, a re-recruitment took place including 2,012 participants: 743 men, 1,269 women (647 deaths, 197 losses, 470 declined further participation). In 2009/2010 n = 1,627 returned the questionnaire (90 deaths, 47 losses, 248 declined further participation) resulting in a good participation rate over ten years with limited and quantified dropouts. Presently, follow-up data from 2007/2008 (wave 2) and 2009/2010 (wave 3) are available. Data wave 4 is due in 2011/2012, and the project will be continued until 2013. Information on survival and need of nursing care was collected continuously and cross-checked against official records. We used Fisher’s exact test and t-tests. The study served repeatedly to evaluate health promotion interventions and concepts. Discussion LUCAS shows that a cohort

  7. Accelerated Aging of Intervertebral Discs in a Mouse Model of Progeria

    PubMed Central

    Vo, Nam; Seo, Hyoung-Yeon; Robinson, Andria; Sowa, Gwendolyn; Bentley, Douglas; Taylor, Lauren; Studer, Rebecca; Usas, Arvydas; Huard, Johnny; Alber, Sean; Watkins, Simon C.; Lee, Joon; Coehlo, Paulo; Wang, Dong; Loppini, Mattia; Robbins, Paul D.; Niedernhofer, Laura J.; Kang, James

    2012-01-01

    Intervertebral disc degeneration (IDD) is a common and debilitating disorder that results in reduced flexibility of the spine, pain, and reduced mobility. Risk factors for IDD include age, genetic predisposition, injury, and other environmental factors such as smoking. Loss of proteoglycans (PGs) contributes to IDD with advancing age. Currently there is a lack of a model for rapid investigation of disc aging and evaluation of therapeutic interventions. Here we examined progression of disc aging in a murine model of a human progeroid syndrome caused by deficiency of the DNA repair endonuclease, ERCC1–XPF (Ercc1−/Δ mice). The ERCC1-deficient mice showed loss of disc height and degenerative structural changes in their vertebral bodies similar to those reported for old rodents. Compared to their wild-type littermates, Ercc1−/Δ mice also exhibit other age-related IDD characteristics, including premature loss of disc PG, reduced matrix PG synthesis, and enhanced apoptosis and cell senescence. Finally, the onset of age-associated disc pathologies was further accelerated in Ercc1−/Δ mice following chronic treatment with the chemotherapeutic agent mechlorethamine. These results demonstrate that Ercc1−/Δ mice represent an accurate and rapid model of disc aging and provide novel evidence that DNA damage negatively impacts PG synthesis. PMID:20973062

  8. Colour stability, opacity and cross-link density of composites submitted to accelerated artificial aging.

    PubMed

    Mundim, Fabrício Mariano; Pires-de-Souza, Fernanda de Carvalho Panzeri; Garcia, Lucas da Fonseca Roberti; Consani, Simonides

    2010-06-01

    The study evaluated the influence of accelerated artificial aging on colour stability, opacity and cross-link density of resin-based composites (RBCs). Seven specimens were obtained of five RBCs (Heliomolar, 4 Seasons, Tetric Evo Ceram, SR Adoro), which were submitted to colour stability and opacity analysis and cross-link density evaluation. All tests were performed before and after aging. After statistical analysis (one-way ANOVA; Tukey; p<0.05), it was observed that QuiXfil and SR Adoro presented colour alteration values above those that are clinically acceptable (deltaE=5.77 and 4.34 respectively) and the variation in opacity was lowest for SR Adoro. There was an increase in the cross-link density of all studied materials after aging.

  9. The effect of accelerated aging on color stability of denture liners.

    PubMed

    Anil, N; Hekimoglu, C; Sahin, S

    1998-09-01

    The objective of the present study was to determine the color changes resulting from the aging process in two cold and three hot curing soft liners and two hard liners. Seven samples were fabricated for each material. The initial color measurements were made with a UV-Visible Recording Spectrophotometer. The samples were then placed in an accelerated aging chamber to simulate the aging process. The color of the samples was then measured again with a colorimeter, and the color changes (delta E) were calculated. The critical mark of color change (delta E) has been quantified by the NBS. It was concluded that cold curing soft liners were not color-stable, and that hot curing soft liners and hard liners had similar color durability. These results suggest that colorants used in cold curing soft liners must be reinforced.

  10. Anticedants and natural prevention of environmental toxicants induced accelerated aging of skin.

    PubMed

    Tanuja Yadav; Mishra, Shivangi; Das, Shefali; Aggarwal, Shikha; Rani, Vibha

    2015-01-01

    Skin is frequently exposed to a variety of environmental and chemical agents that accelerate ageing. External stress such as UV radiations (UVR) and environmental pollutants majorly deteriorate the skin morphology, by activating certain intrinsic factors such as Reactive Oxygen Species (ROS) which trigger the activation of Matrix Metalloproteinases (MMPs) and inflammatory responses hence damaging the extracellular matrix (ECM) components. To counter this, an exogenous supply of anti-oxidants, is required since the endogenous anti-oxidant system cannot alone suffice the need. Bio-prospecting of natural resources for anti-oxidants has hence been intensified. Immense research is being carried out to identify potential plants with potent anti-oxidant activity against skin ageing. This review summarizes the major factors responsible for premature skin ageing and the plants being targeted to lessen the impact of those. PMID:25555260

  11. Anticedants and natural prevention of environmental toxicants induced accelerated aging of skin.

    PubMed

    Tanuja Yadav; Mishra, Shivangi; Das, Shefali; Aggarwal, Shikha; Rani, Vibha

    2015-01-01

    Skin is frequently exposed to a variety of environmental and chemical agents that accelerate ageing. External stress such as UV radiations (UVR) and environmental pollutants majorly deteriorate the skin morphology, by activating certain intrinsic factors such as Reactive Oxygen Species (ROS) which trigger the activation of Matrix Metalloproteinases (MMPs) and inflammatory responses hence damaging the extracellular matrix (ECM) components. To counter this, an exogenous supply of anti-oxidants, is required since the endogenous anti-oxidant system cannot alone suffice the need. Bio-prospecting of natural resources for anti-oxidants has hence been intensified. Immense research is being carried out to identify potential plants with potent anti-oxidant activity against skin ageing. This review summarizes the major factors responsible for premature skin ageing and the plants being targeted to lessen the impact of those.

  12. Lung Master Protocol (Lung-MAP)—A Biomarker-Driven Protocol for Accelerating Development of Therapies for Squamous Cell Lung Cancer: SWOG S1400

    PubMed Central

    Herbst, Roy S.; Gandara, David R.; Hirsch, Fred R.; Redman, Mary W.; LeBlanc, Michael; Mack, Philip C.; Schwartz, Lawrence H.; Vokes, Everett; Ramalingam, Suresh S.; Bradley, Jeffrey D.; Sparks, Dana; Zhou, Yang; Miwa, Crystal; Miller, Vincent A.; Yelensky, Roman; Li, Yali; Allen, Jeff D.; Sigal, Ellen V.; Wholley, David; Sigman, Caroline C.; Blumenthal, Gideon M.; Malik, Shakun; Kelloff, Gary J.; Abrams, Jeffrey S.; Blanke, Charles D.; Papadimitrakopoulou, Vassiliki A.

    2015-01-01

    The Lung Master Protocol (Lung-MAP, S1400) is a groundbreaking clinical trial designed to advance the efficient development of targeted therapies for squamous cell cancer (SCCA) of the lung. There are no approved targeted therapies specific to advanced lung SCCA, although The Cancer Genome Atlas (TCGA) project and similar studies have detected a significant number of somatic gene mutations/amplifications in lung SCCA, some of which are targetable by investigational agents. However, the frequency of these changes is low (5–20%), making recruitment and study conduct challenging in the traditional clinical trial setting. Here we describe our approach to development of a biomarker-driven phase 2/3 multi-substudy “Master Protocol,” employing a common platform (Next Generation DNA Sequencing) to identify actionable molecular abnormalities, followed by randomization to the relevant targeted therapy versus standard of care. PMID:25680375

  13. Lung Master Protocol (Lung-MAP)-A Biomarker-Driven Protocol for Accelerating Development of Therapies for Squamous Cell Lung Cancer: SWOG S1400.

    PubMed

    Herbst, Roy S; Gandara, David R; Hirsch, Fred R; Redman, Mary W; LeBlanc, Michael; Mack, Philip C; Schwartz, Lawrence H; Vokes, Everett; Ramalingam, Suresh S; Bradley, Jeffrey D; Sparks, Dana; Zhou, Yang; Miwa, Crystal; Miller, Vincent A; Yelensky, Roman; Li, Yali; Allen, Jeff D; Sigal, Ellen V; Wholley, David; Sigman, Caroline C; Blumenthal, Gideon M; Malik, Shakun; Kelloff, Gary J; Abrams, Jeffrey S; Blanke, Charles D; Papadimitrakopoulou, Vassiliki A

    2015-04-01

    The Lung Master Protocol (Lung-MAP, S1400) is a groundbreaking clinical trial designed to advance the efficient development of targeted therapies for squamous cell carcinoma (SCC) of the lung. There are no approved targeted therapies specific to advanced lung SCC, although The Cancer Genome Atlas project and similar studies have detected a significant number of somatic gene mutations/amplifications in lung SCC, some of which are targetable by investigational agents. However, the frequency of these changes is low (5%-20%), making recruitment and study conduct challenging in the traditional clinical trial setting. Here, we describe our approach to development of a biomarker-driven phase II/II multisubstudy "Master Protocol," using a common platform (next-generation DNA sequencing) to identify actionable molecular abnormalities, followed by randomization to the relevant targeted therapy versus standard of care.

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

    PubMed

    Rickabaugh, Tammy M; Baxter, Ruth M; 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, 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 are

  15. Time dependent diffusive shock acceleration and its application to middle aged supernova remnants

    NASA Astrophysics Data System (ADS)

    Tang, Xiaping; Chevalier, Roger A.

    2016-06-01

    Recent gamma-ray observations show that middle aged supernova remnants (SNRs) interacting with molecular clouds (MCs) can be sources of both GeV and TeV emission. Based on the MC association, two scenarios have been proposed to explain the observed gamma-ray emission. In one, energetic cosmic ray (CR) particles escape from the SNR and then illuminate nearby MCs, producing gamma-ray emission, while the other involves direct interaction between the SNR and MC. In the direct interaction scenario, re-acceleration of pre-existing CRs in the ambient medium is investigated while particles injected from the thermal pool are neglected in view of the slow shock speeds in middle aged SNRs. However, standard diffusive shock acceleration (DSA) theory produces a steady state particle spectrum that is too flat compared to observations, which suggests that the high energy part of the observed spectrum has not yet reached a steady state. We derive a time dependent DSA solution in the test particle limit for re-acceleration of pre-existing CRs case and show that it is capable of reproducing the observed gamma-ray emission in SNRs like IC 443 and W44, in the context of a MC interaction model. We also provide a simple physical picture to understand the time dependent DSA spectrum. A spatially averaged diffusion coefficient around the SNR can be estimated through fitting the gamma-ray spectrum. The spatially averaged diffusion coefficient in middle aged SNRs like IC 443 and W44 is estimated to be ~10^(25) cm^2/s at ~ 1GeV, which is between the Bohm limit and interstellar value.

  16. Length velocity acceleration at 9 months of age in a representative birth cohort of Dutch infants.

    PubMed

    Van den Broeck, J; Brand, R; Massa, G; Herngreen, W P; Wit, J M

    2000-01-01

    According to the ICP (infancy-childhood-puberty) growth model, statural growth can be divided into three partially superimposed components assumed to represent different physiologic mechanisms. This model predicts a sudden acceleration of length velocity (LV) at the onset of the childhood component around 9 months. The existence of such an infancy-childhood growth spurt has not yet been firmly corroborated by epidemiological studies. In the present study length measurements were made at the target ages of 1, 3, 6, 9, 12, 15, 18 and 24 months in a birth cohort of 2034 infants. In order to check whether length growth showed a continuous smooth pattern, different mathematical models were fitted to the individual growth curves. The models included Count and Guo functions, 5th order polynomial and combinations of 5th order polynomial with the logarithmic term of the Count function and the square root term of the Guo function. We showed that in boys and girls there is a small but systematic lack of fit of the mathematical modeling, due to a sudden acceleration of LV around 9 months. In addition there was an increase in variation of attained length at this age. Comparison of unbalanced ANOVA models with and without addition of dummy variables for the target ages confirmed that there was an acceleration around 9 months that, if corrected for, leads to a significantly improved model fit (likelihood ratio test p < 0.0001). In absolute terms of LV, the misfit at 9 months was not greater than 0.5 cm/year on average. We conclude that the results of this study support the existence of a late infancy growth spurt. In our opinion, however, the magnitude of the phenomenon does not legitimate construction and use of discontinuous growth references such as the ICP reference.

  17. Functionality, growth and accelerated aging of tissue engineered living autologous vascular grafts.

    PubMed

    Kelm, Jens M; Emmert, Maximilian Y; Zürcher, Armin; Schmidt, Dörthe; Begus Nahrmann, Yvonne; Rudolph, Karl L; Weber, Benedikt; Brokopp, Chad E; Frauenfelder, Thomas; Leschka, Sebastian; Odermatt, Bernhard; Jenni, Rolf; Falk, Volkmar; Zünd, Gregor; Hoerstrup, Simon P

    2012-11-01

    Living autologous tissue engineered vascular-grafts (TEVGs) with growth-capacity may overcome the limitations of contemporary artificial-prostheses. However, the multi-step in vitro production of TEVGs requires extensive ex vivo cell-manipulations with unknown effects on functionality and quality of TEVGs due to an accelerated biological age of the cells. Here, the impact of biological cell-age and tissue-remodeling capacity of TEVGs in relation to their clinical long-term functionality are investigated. TEVGs were implanted as pulmonary-artery (PA) replacements in juvenile sheep and followed for up to 240 weeks (∼4.5years). Telomere length and telomerase activity were compared amongst TEVGs and adjacent native tissue. Telomerase-activity of in vitro expanded autologous vascular-cells prior to seeding was <5% as compared to a leukemic cell line, indicating biological-aging associated with decreasing telomere-length with each cellular-doubling. Up to 100 weeks, the cells in the TEVGs had consistently shorter telomeres compared to the native counterpart, whereas no significant differences were detectable at 240 weeks. Computed tomography (CT) analysis demonstrated physiological wall-pressures, shear-stresses, and flow-pattern comparable to the native PA. There were no signs of degeneration detectable and continuous native-analogous growth was confirmed by vessel-volumetry. TEVGs exhibit a higher biological age compared to their native counterparts. However, despite of this tissue engineering technology related accelerated biological-aging, growth-capacity and long-term functionality was not compromised. To the contrary, extensive in-vivo remodeling processes with substantial endogenous cellular turnover appears to result in "TEVG rejuvenation" and excellent clinical performance. As these large-animal results can be extrapolated to approximately 20 human years, this study suggests long-term clinical-safety of cardiovascular in vitro tissue engineering and may

  18. Accelerated fibrosis and apoptosis with ageing and in atrial fibrillation: Adaptive responses with maladaptive consequences

    PubMed Central

    XU, GUO-JUN; GAN, TIAN-YI; TANG, BAO-PENG; CHEN, ZU-HENG; MAHEMUTI, AILIMAN; JIANG, TAO; SONG, JIAN-GUO; GUO, XIA; LI, YAO-DONG; MIAO, HAI-JUN; ZHOU, XIAN-HUI; ZHANG, YU; LI, JIN-XIN

    2013-01-01

    The aim of this study was to investigate whether abnormal expression of matrix metalloproteinase (MMP)-9/tissue inhibitors of MMPs (TIMP)-1 and B cell lymphoma 2 (BCL-2)/BCL-2-associated X protein (BAX) are correlated with the characteristic accelerated fibrosis and apoptosis during ageing and in atrial fibrillation (AF). Four groups of dogs were studied: adult dogs in sinus rhythm (SR), aged dogs in SR, adult dogs with AF induced by rapid atrial pacing and aged dogs with AF induced by rapid atrial pacing. The mRNA and protein expression levels of the target gene in the left atrium were measured by quantitative reverse transcription-polymerase chain reaction (RT-PCR) and western blot analysis. Pathohistological and ultrastructural changes were assessed by light and electron microscopy. The apoptotic indices of myocytes were detected by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL). The mRNA and protein expression levels of MMP-9 and BAX and those of TIMP-1 and BCL-2 were significantly upregulated and down-regulated, respectively, in the aged groups compared with the adult groups. Compared with the control groups, the adult and aged groups with AF exhibited significantly increased mRNA and protein expression levels of MMP-9 and BAX and decreased expression levels of TIMP-1 and BCL-2. Samples of atrial tissue demonstrated abnormal pathohistological and ultrastructural changes, accelerated fibrosis and apoptosis. MMP-9/TIMP-1 and BCL-2/BAX hold potential for use as substrates conducive to AF and their abnormal expression plays a major role in structural remodeling of the atrium. PMID:23403858

  19. Psychiatric Disorders, Morbidity, and Mortality: Tracing Mechanistic Pathways to Accelerated Aging.

    PubMed

    Kiecolt-Glaser, Janice K; Wilson, Stephanie J

    2016-09-01

    A meta-analysis published in this issue of Psychosomatic Medicine provides convincing evidence that certain psychiatric populations have shorter telomeres than nonpsychiatric controls, in accord with the strong evidence linking psychiatric disorders with premature mortality. After addressing the clinical significance of shorter telomeres, this editorial describes mechanistic pathways that lead to telomere shortening. Additionally, two other novel methods for measuring biological markers of accelerated aging are briefly discussed: DNA methylation and cellular senescence based on p16. These innovative approaches could be used to confirm and extend our understanding of psychiatric patients' increased health and mortality risks.

  20. Holocene age of the Yuha burial: Direct radiocarbon determinations by accelerator mass spectrometry

    USGS Publications Warehouse

    Stafford, Thomas W.; Jull, A.J.T.; Zabel, T.H.; Donahue, D.J.; Duhamel, R.C.; Brendel, K.; Haynes, C.V.; Bischoff, J.L.; Payen, L.A.; Taylor, R.E.

    1984-01-01

    The view that human populations may not have arrived in the Western Hemisphere before about 12,000 radiocarbon yr BP1,2 has been challenged by claims of much greater antiquity for a small number of archaeological sites and human skeleton samples. One such site is the Homo sapiens sapiens cairn burial excavated in 1971 from the Yuha desert, Imperial County, California3-5. Radiocarbon analysis of caliche coating one of the bones of the skeleton yielded a radiocarbon age of 21,500??1,000 yr BP4, while radiocarbon and uranium series analyses of caliche coating a cairn boulder yielded ages of 22,125??400 and 19,000??3,000 yr BP, respectively5. The late Pleistocene age assignment to the Yuha burial has been challenged by comparing the cultural context of the burial with other cairn burials in the same region6, on the basis of the site's geomorphological context and from radiocarbon analyses of soil caliches. 7,8 In rebuttal, arguments in defence of the original age assignment have been presented9,10 as well as an amino acid racemization analysis on the Yuha skeleton indicating an age of 23,600??2,600 yr BP11. The tandem accelerator mass spectrometer at the University of Arizona has now been used to measure the ratio of 14C/13C in several organic and inorganic fractions of post-cranial bone from the Yuha H. sapiens sapiens skeleton. Isotope ratios from six chemical fractions all yielded radiocarbon ages for the skeleton of less than 4,000 yr BP. These results indicate that the Yuha skeleton is of Holocene age, in agreement with the cultural context of the burial, and in disagreement with the previously assigned Pleistocene age of 19,000-23,000 yr. ?? 1984 Nature Publishing Group.

  1. Improving Bone Microarchitecture in Aging with Diosgenin Treatment: A Study in Senescence-Accelerated OXYS Rats.

    PubMed

    Tikhonova, Maria A; Ting, Che-Hao; Kolosova, Nataliya G; Hsu, Chao-Yu; Chen, Jian-Horng; Huang, Chi-Wen; Tseng, Ging-Ting; Hung, Ching-Sui; Kao, Pan-Fu; Amstislavskaya, Tamara G; Ho, Ying-Jui

    2015-10-31

    Osteoporosis is a major disease associated with aging. We have previously demonstrated that diosgenin prevents osteoporosis in both menopause and D-galactose-induced aging rats. OXYS rats reveal an accelerated senescence and are used as a suitable model of osteoporosis. The aim of the present study was to analyze microarchitecture and morphological changes in femur of OXYS rats using morphological tests and microcomputed tomography scanning, and to evaluate the effects of oral administration of diosgenin at 10 and 50 mg/kg/day on femur in OXYS rats. The result showed that, compared with age-matched Wistar rats, the femur of OXYS rats revealed lower bone length, bone weight, bone volume, frame volume, frame density, void volume, porosity, external and internal diameters, cortical bone area, BV/TV, Tb.N, and Tb.Th, but higher Tb.Sp. Eight weeks of diosgenin treatment decreased porosity and Tb.Sp, but increased BV/TV, cortical bone area, Tb.N and bone mineral density, compared with OXYS rats treated with vehicle. These data reveal that microarchitecture and morphological changes in femur of OXYS rats showed osteoporotic aging features and suggest that diosgenin may have beneficial effects on aging-induced osteoporosis. PMID:26387656

  2. The signaling pathways by which the Fas/FasL system accelerates oocyte aging

    PubMed Central

    Zhu, Jiang; Lin, Fei-Hu; Zhang, Jie; Lin, Juan; Li, Hong; Li, You-Wei; Tan, Xiu-Wen; Tan, Jing-He

    2016-01-01

    In spite of great efforts, the mechanisms for postovulatory oocyte aging are not fully understood. Although our previous work showed that the FasL/Fas signaling facilitated oocyte aging, the intra-oocyte signaling pathways are unknown. Furthermore, the mechanisms by which oxidative stress facilitates oocyte aging and the causal relationship between Ca2+ rises and caspase-3 activation and between the cell cycle and apoptosis during oocyte aging need detailed investigations. Our aim was to address these issues by studying the intra-oocyte signaling pathways for Fas/FasL to accelerate oocyte aging. The results indicated that sFasL released by cumulus cells activated Fas on the oocyte by increasing reactive oxygen species via activating NADPH oxidase. The activated Fas triggered Ca2+ release from the endoplasmic reticulum by activating phospholipase C-γ pathway and cytochrome c pathway. The cytoplasmic Ca2+ rises activated calcium/calmodulin-dependent protein kinase II (CaMKII) and caspase-3. While activated CaMKII increased oocyte susceptibility to activation by inactivating maturation-promoting factor (MPF) through cyclin B degradation, the activated caspase-3 facilitated further Ca2+ releasing that activates more caspase-3 leading to oocyte fragmentation. Furthermore, caspase-3 activation and fragmentation were prevented in oocytes with a high MPF activity, suggesting that an oocyte must be in interphase to undergo apoptosis. PMID:26869336

  3. Skeletal Involution by Age-associated Oxidative Stress and Its Acceleration by Loss of Sex Steroids*

    PubMed Central

    Almeida, Maria; Han, Li; Martin-Millan, Marta; Plotkin, Lilian I.; Stewart, Scott A.; Roberson, Paula K.; Kousteni, Stavroula; O’Brien, Charles A.; Bellido, Teresita; Parfitt, A. Michael; Weinstein, Robert S.; Jilka, Robert L.; Manolagas, Stavros C.

    2011-01-01

    Both aging and loss of sex steroids have adverse effects on skeletal homeostasis, but whether and how they may influence each others negative impact on bone remains unknown. We report herein that both female and male C57BL/6 mice progressively lost strength (as determined by load-to-failure measurements) and bone mineral density in the spine and femur between the ages of 4 and 31 months. These changes were temporally associated with decreased rate of remodeling as evidenced by decreased osteoblast and osteoclast numbers and decreased bone formation rate; as well as increased osteoblast and osteocyte apoptosis, increased reactive oxygen species levels, and decreased glutathione reductase activity and a corresponding increase in the phosphorylation of p53 and p66shc, two key components of a signaling cascade that are activated by reactive oxygen species and influences apoptosis and lifespan. Exactly the same changes in oxidative stress were acutely reproduced by gonadectomy in 5-month-old females or males and reversed by estrogens or androgens in vivo as well as in vitro.We conclude that the oxidative stress that underlies physiologic organismal aging in mice may be a pivotal pathogenetic mechanism of the age-related bone loss and strength. Loss of estrogens or androgens accelerates the effects of aging on bone by decreasing defense against oxidative stress. PMID:17623659

  4. Impact absorption of four processed soft denture liners as influenced by accelerated aging.

    PubMed

    Kawano, F; Koran, A; Nuryanti, A; Inoue, S

    1997-01-01

    The cushioning effect of soft denture liners was evaluated by using a free drop test with an accelerometer. Materials tested included SuperSoft (Coe Laboratories, Chicago, IL), Kurepeet-Dough (Kreha Chemical, Tokyo), Molteno Soft (Molten, Hiroshima, Japan), and Molloplast-B (Molloplast Regneri, Karlsruhe, Germany). All materials were found to reduce the impact force when compared to acrylic denture base resin. A 2.4-mm layer of soft denture material demonstrated good impact absorption, and Molloplast-B and Molteno had excellent impact absorption. When the soft denture liner was kept in an accelerated aging chamber for 900 hours, the damping effect recorded increased for all materials tested. Aging of all materials also affected the cushioning effect.

  5. Impulse noise exposure in early adulthood accelerates age-related hearing loss.

    PubMed

    Xiong, Min; Yang, Chuanhong; Lai, Huangwen; Wang, Jian

    2014-06-01

    The aim of this study was to investigate the influence of impulse noise on age-related hearing loss. The study consisted of two groups. Each group contained 109 men. Group I comprised veterans with normal hearing at the end of 1979 sino-vietnamese war. All these veterans were randomly selected from Guangzhou Military Command. Group II were men with no military experience randomly chosen from the health examination center of Guangzhou General Hospital of Guangzhou Military Command. Pure-tone thresholds of these two groups were measured and compared. The pure-tone thresholds of Group I were poorer than those of Group II at the frequencies of 4, 6 and 8 kHz. Thus, impulse noise accelerates age-related hearing loss.

  6. The electrical performance of polymeric insulating materials under accelerated aging in a fog chamber

    SciTech Connect

    Gorur, R.S.; Cherney, E.A.; Hackam, R. ); Orbeck, T. )

    1988-07-01

    A comparative study of the ac (60 Hz) surface aging in a fog chamber is reported on cylindrical rod samples of high temperature vulcanized (HTV) silicone rubber and ethylene propylene diene monomer (EPDM) rubber containing various amounts of alumina trihydrate (ATH) and/or silica fillers. In low conductivity (250 ..mu..S/cm) fog, silicone rubber performed better than EPDM samples whereas in high conductivity (1000 ..mu..S/cm) fog, the order of performance was reversed. The mechanisms by which fillers impart tracking and erosion resistance to materials is discussed as influenced by the experimental conditions of the accelerated aging tests. Surface studies by ESCA (Electron Spectroscopy for Chemical Analysis) demonstrate that the hydrophobicity of silicone rubber, despite the accumulation of surface contamination, can be attributed to migration of low molecular weight polymer chains and/or mobile fluids, such as silicone oil.

  7. A Model-based Prognostics Methodology for Electrolytic Capacitors Based on Electrical Overstress Accelerated Aging

    NASA Technical Reports Server (NTRS)

    Celaya, Jose; Kulkarni, Chetan; Biswas, Gautam; Saha, Sankalita; Goebel, Kai

    2011-01-01

    A remaining useful life prediction methodology for electrolytic capacitors is presented. This methodology is based on the Kalman filter framework and an empirical degradation model. Electrolytic capacitors are used in several applications ranging from power supplies on critical avionics equipment to power drivers for electro-mechanical actuators. These devices are known for their comparatively low reliability and given their criticality in electronics subsystems they are a good candidate for component level prognostics and health management. Prognostics provides a way to assess remaining useful life of a capacitor based on its current state of health and its anticipated future usage and operational conditions. We present here also, experimental results of an accelerated aging test under electrical stresses. The data obtained in this test form the basis for a remaining life prediction algorithm where a model of the degradation process is suggested. This preliminary remaining life prediction algorithm serves as a demonstration of how prognostics methodologies could be used for electrolytic capacitors. In addition, the use degradation progression data from accelerated aging, provides an avenue for validation of applications of the Kalman filter based prognostics methods typically used for remaining useful life predictions in other applications.

  8. Physical property comparison of 11 soft denture lining materials as a function of accelerated aging.

    PubMed

    Dootz, E R; Koran, A; Craig, R G

    1993-01-01

    Soft denture-lining materials are an important treatment option for patients who have chronic soreness associated with dental prostheses. Three distinctly different types of materials are generally used. These are plasticized polymers or copolymers, silicones, or polyphosphazene fluoroelastomer. The acceptance of these materials by patients and dentists is variable. The objective of this study is to compare the tensile strength, percent elongation, hardness, tear strength, and tear energy of eight plasticized polymers or copolymers, two silicones, and one polyphosphazene fluoroelastomer. Tests were run at 24 hours after specimen preparation and repeated after 900 hours of accelerated aging in a Weather-Ometer device. The data indicated a wide range of physical properties for soft denture-lining materials and showed that accelerated aging dramatically affected the physical and mechanical properties of many of the elastomers. No soft denture liner proved to be superior to all others. The data obtained should provide clinicians with useful information for selecting soft denture lining materials for patients.

  9. Macrophage Response to UHMWPE Submitted to Accelerated Ageing in Hydrogen Peroxide.

    PubMed

    Rocha, Magda F G; Mansur, Alexandra A P; Martins, Camila P S; Barbosa-Stancioli, Edel F; Mansur, Herman S

    2010-01-01

    Ultra-high molecular weight polyethylene (UHMWPE) has been the most commonly used bearing material in total joint arthroplasty. Wear and oxidation fatigue resistance of UHMWPE are regarded as two important properties to extend the longevity of knee prostheses. The present study investigated the accelerated ageing of UHMWPE in hydrogen peroxide highly oxidative chemical environment. The sliced samples of UHMWPE were oxidized in a hydrogen peroxide solution for 120 days with their total level of oxidation (Iox) characterized by Fourier Transformed Infrared Spectroscopy (FTIR). The potential inflammatory response, cell viability and biocompatibility of such oxidized UHMWPE systems were assessed by a novel biological in vitro assay based on the secretion of nitric oxide (NO) by activated murine macrophages with gamma interferon (IFN-gamma) cytokine and lipopolysaccharide (LPS). Furthermore, macrophage morphologies in contact with UHMWPE oxidized surfaces were analyzed by cell spreading-adhesion procedure using scanning electron microscopy (SEM). The results have given significant evidence that the longer the period of accelerated aging of UHMWPE the higher was the macrophage inflammatory equivalent response based on NO secretion analysis.

  10. Validation of accelerated ageing of Thales rotary Stirling cryocoolers for the estimation of MTTF

    NASA Astrophysics Data System (ADS)

    Seguineau, C.,; Cauquil, J.-M.; Martin, J.-Y.; Benschop, T.

    2016-05-01

    The cooled IR detectors are used in a wide range of applications. Most of the time, the cryocoolers are one of the components dimensioning the lifetime of the system. The current market needs tend to reliability figures higher than 15,000hrs in "standard conditions". Field returns are hardly useable mostly because of the uncertain environmental conditions of use, or the differences in user profiles. A previous paper explains how Thales Cryogenics has developed an approach based on accelerated ageing and statistical analysis [1]. The aim of the current paper is to compare results obtained on accelerated ageing on one side, and on the other side, specific field returns where the conditions of use are well known. The comparison between prediction and effective failure rate is discussed. Moreover, a specific focus is done on how some new applications of cryocoolers (continuous operation at a specific temperature) can increase the MTTF. Some assumptions are also exposed on how the failure modes, effects and criticality analysis evolves for continuous operation at a specific temperature and compared to experimental data.

  11. Bisphenol A exposure accelerated the aging process in the nematode Caenorhabditis elegans.

    PubMed

    Tan, Ling; Wang, Shunchang; Wang, Yun; He, Mei; Liu, Dahai

    2015-06-01

    Bisphenol A (BPA) is a well-known environmental estrogenic disruptor that causes adverse effects. Recent studies have found that chronic exposure to BPA is associated with a high incidence of several age-related diseases. Aging is characterized by progressive function decline, which affects quality of life. However, the effects of BPA on the aging process are largely unknown. In the present study, by using the nematode Caenorhabditis elegans as a model, we investigated the influence of BPA exposure on the aging process. The decrease in body length, fecundity, and population size and the increased egg laying defection suggested that BPA exposure resulted in fitness loss and reproduction aging in this animal. Lifetime exposure of worms to BPA shortened the lifespan in a dose-dependant manner. Moreover, prolonged BPA exposure resulted in age-related behavior degeneration and the accumulation of lipofuscin and lipid peroxide products. The expression of mitochondria-specific HSP-6 and endoplasmic reticulum (ER)-related HSP-70 exhibited hormetic decrease. The expression of ER-related HSP-4 decreased significantly while HSP-16.2 showed a dose-dependent increase. The decreased expression of GCS-1 and GST-4 implicated the reduced antioxidant ability under BPA exposure, and the increase in SOD-3 expression might be caused by elevated levels of reactive oxygen species (ROS) production. Finally, BPA exposure increased the generation of hydrogen peroxide-related ROS and superoxide anions. Our results suggest that BPA exposure resulted in an accelerated aging process in C. elegans mediated by the induction of oxidative stress.

  12. The senescence-accelerated mouse (SAM): a higher oxidative stress and age-dependent degenerative diseases model.

    PubMed

    Chiba, Yoichi; Shimada, Atsuyoshi; Kumagai, Naoko; Yoshikawa, Keisuke; Ishii, Sanae; Furukawa, Ayako; Takei, Shiro; Sakura, Masaaki; Kawamura, Noriko; Hosokawa, Masanori

    2009-04-01

    The SAM strain of mice is actually a group of related inbred strains consisting of a series of SAMP (accelerated senescence-prone) and SAMR (accelerated senescence-resistant) strains. Compared with the SAMR strains, the SAMP strains show a more accelerated senescence process, a shorter lifespan, and an earlier onset and more rapid progress of age-associated pathological phenotypes similar to human geriatric disorders. The higher oxidative stress status observed in SAMP mice is partly caused by mitochondrial dysfunction, and may be a cause of this senescence acceleration and age-dependent alterations in cell structure and function. Based on our recent observations, we discuss a possible mechanism for mitochondrial dysfunction resulting in the excessive production of reactive oxygen species, and a role for the hyperoxidative stress status in neurodegeneration in SAMP mice. These SAM strains can serve as a useful tool to understand the cellular mechanisms of age-dependent degeneration, and to develop clinical interventions. PMID:18688709

  13. Fat-specific Dicer deficiency accelerates aging and mitigates several effects of dietary restriction in mice

    PubMed Central

    Reis, Felipe C. G.; Branquinho, Jéssica L. O.; Brandão, Bruna B.; Guerra, Beatriz A.; Silva, Ismael D.; Frontini, Andrea; Thomou, Thomas; Sartini, Loris; Cinti, Saverio; Kahn, C. Ronald; Festuccia, William T.; Kowaltowski, Alicia J.; Mori, Marcelo A.

    2016-01-01

    Aging increases the risk of type 2 diabetes, and this can be prevented by dietary restriction (DR). We have previously shown that DR inhibits the downregulation of miRNAs and their processing enzymes - mainly Dicer - that occurs with aging in mouse white adipose tissue (WAT). Here we used fat-specific Dicer knockout mice (AdicerKO) to understand the contributions of adipose tissue Dicer to the metabolic effects of aging and DR. Metabolomic data uncovered a clear distinction between the serum metabolite profiles of Lox control and AdicerKO mice, with a notable elevation of branched-chain amino acids (BCAA) in AdicerKO. These profiles were associated with reduced oxidative metabolism and increased lactate in WAT of AdicerKO mice and were accompanied by structural and functional changes in mitochondria, particularly under DR. AdicerKO mice displayed increased mTORC1 activation in WAT and skeletal muscle, where Dicer expression is not affected. This was accompanied by accelerated age-associated insulin resistance and premature mortality. Moreover, DR-induced insulin sensitivity was abrogated in AdicerKO mice. This was reverted by rapamycin injection, demonstrating that insulin resistance in AdicerKO mice is caused by mTORC1 hyperactivation. Our study evidences a DR-modulated role for WAT Dicer in controlling metabolism and insulin resistance. PMID:27241713

  14. Fat-specific Dicer deficiency accelerates aging and mitigates several effects of dietary restriction in mice.

    PubMed

    Reis, Felipe C G; Branquinho, Jéssica L O; Brandão, Bruna B; Guerra, Beatriz A; Silva, Ismael D; Frontini, Andrea; Thomou, Thomas; Sartini, Loris; Cinti, Saverio; Kahn, C Ronald; Festuccia, William T; Kowaltowski, Alicia J; Mori, Marcelo A

    2016-06-01

    Aging increases the risk of type 2 diabetes, and this can be prevented by dietary restriction (DR). We have previously shown that DR inhibits the downregulation of miRNAs and their processing enzymes - mainly Dicer - that occurs with aging in mouse white adipose tissue (WAT). Here we used fat-specific Dicer knockout mice (AdicerKO) to understand the contributions of adipose tissue Dicer to the metabolic effects of aging and DR. Metabolomic data uncovered a clear distinction between the serum metabolite profiles of Lox control and AdicerKO mice, with a notable elevation of branched-chain amino acids (BCAA) in AdicerKO. These profiles were associated with reduced oxidative metabolism and increased lactate in WAT of AdicerKO mice and were accompanied by structural and functional changes in mitochondria, particularly under DR. AdicerKO mice displayed increased mTORC1 activation in WAT and skeletal muscle, where Dicer expression is not affected. This was accompanied by accelerated age-associated insulin resistance and premature mortality. Moreover, DR-induced insulin sensitivity was abrogated in AdicerKO mice. This was reverted by rapamycin injection, demonstrating that insulin resistance in AdicerKO mice is caused by mTORC1 hyperactivation. Our study evidences a DR-modulated role for WAT Dicer in controlling metabolism and insulin resistance. PMID:27241713

  15. Caveolin-1 and Accelerated Host Aging in the Breast Tumor Microenvironment

    PubMed Central

    Mercier, Isabelle; Camacho, Jeanette; Titchen, Kanani; Gonzales, Donna M.; Quann, Kevin; Bryant, Kelly G.; Molchansky, Alexander; Milliman, Janet N.; Whitaker-Menezes, Diana; Sotgia, Federica; Jasmin, Jean-François; Schwarting, Roland; Pestell, Richard G.; Blagosklonny, Mikhail V.; Lisanti, Michael P.

    2013-01-01

    Increasing chronological age is the most significant risk factor for human cancer development. To examine the effects of host aging on mammary tumor growth, we used caveolin (Cav)-1 knockout mice as a bona fide model of accelerated host aging. Mammary tumor cells were orthotopically implanted into these distinct microenvironments (Cav-1+/+ versus Cav-1−/− age-matched young female mice). Mammary tumors grown in a Cav-1–deficient tumor microenvironment have an increased stromal content, with vimentin-positive myofibroblasts (a marker associated with oxidative stress) that are also positive for S6-kinase activation (a marker associated with aging). Mammary tumors grown in a Cav-1–deficient tumor microenvironment were more than fivefold larger than tumors grown in a wild-type microenvironment. Thus, a Cav-1–deficient tumor microenvironment provides a fertile soil for breast cancer tumor growth. Interestingly, the mammary tumor-promoting effects of a Cav-1–deficient microenvironment were estrogen and progesterone independent. In this context, chemoprevention was achieved by using the mammalian target of rapamycin (mTOR) inhibitor and anti-aging drug, rapamycin. Systemic rapamycin treatment of mammary tumors grown in a Cav-1–deficient microenvironment significantly inhibited their tumor growth, decreased their stromal content, and reduced the levels of both vimentin and phospho-S6 in Cav-1–deficient cancer-associated fibroblasts. Since stromal loss of Cav-1 is a marker of a lethal tumor microenvironment in breast tumors, these high-risk patients might benefit from treatment with mTOR inhibitors, such as rapamycin or other rapamycin-related compounds (rapalogues). PMID:22698676

  16. A Collaborative Protocol for Encopresis Management in School-Aged Children.

    ERIC Educational Resources Information Center

    Chaney, Carol A.

    1995-01-01

    Encopresis affects a small percentage of children, but most parents are unaware of the condition and react punitively. The lengthy, complex management program usually includes physiological and behavioral approaches. The collaborative management protocol focuses on medical clinicians, families, children, school nurses, and teachers, and can help…

  17. Evaluation of oxidative behavior of polyolefin geosynthetics utilizing accelerated aging tests based on temperature and pressure

    NASA Astrophysics Data System (ADS)

    Li, Mengjia

    Polyolefin geosynthetics are susceptible to oxidation, which eventually leads to the reduction in their engineering properties. In the application of polyolefin geosynthetics, a major issue is an estimate of the materials durability (i.e. service lifetime) under various aging conditions. Antioxidant packages are added to the polyolefin products to extend the induction time, during which antioxidants are gradually depleted and polymer oxidation reactions are prevented. In this PhD study, an improved laboratory accelerating aging method under elevated and high pressure environments was applied to evaluate the combined effect of temperature and pressure on the depletion of the antioxidants and the oxidation of polymers. Four types of commercial polyolefn geosynthetic materials selected for aging tests included HDPE geogrid, polypropylene woven and nonwoven geotextiles. A total of 33 different temperature/pressure aging conditions were used, with the incubation duration up to 24 months. The applied oven temperature ranged from 35°C to 105°C and the partial oxygen pressure ranged from 0.005 MPa to 6.3 MPa. Using the Oxidative Induction Time (OIT) test, the antioxidant depletion, which is correlated to the decrease of the OIT value, was found to follow apparent first-order decay. The OIT data also showed that, the antioxidant depletion rate increased with temperature according to the Arrhenius equation, while under constant temperatures, the rate increased exponentially with the partial pressure of oxygen. A modified Arrhenius model was developed to fit the antioxidant depletion rate as a function of temperature and pressure and to predict the antioxidant lifetime under various field conditions. This study has developed new temperature/pressure incubation aging test method with lifetime prediction models. Using this new technique, the antioxidant lifetime prediction results are close to regular temperature aging data while the aging duration can be reduced considerably

  18. Accelerated aging of extruded dielectric power cables. Part 2; Life testing of 15 kV XLPE-insulated cables

    SciTech Connect

    Bernstein, B.S.; Thue, W.A. ); Walton, M.D.; Smith J.T. III )

    1992-04-01

    Attempts to successfully use accelerated aging tests to quantify the life of medium voltage power cables in service have been elusive. This paper describes preliminary results in which 15 kV XLPE cables were subjected to accelerated aging tests under a variety of controlled voltage stress and thermal load cycle conditions, with loss of life being calculated for each set of conditions in terms of the geometric mean time to failure (GMTF). In this paper the relative influence of voltage stress and load cycle temperature are discussed. This work is part of a broad effort that also involves studies with EPR-insulated cables, accelerated aging of cables from the same manufacturing run that are direct buried at the manufacturer's site, and also aging of these cables under normal operating conditions at four United States utilities.

  19. A drug-induced accelerated senescence (DIAS) is a possibility to study aging in time lapse.

    PubMed

    Alili, Lirija; Diekmann, Johanna; Giesen, Melanie; Holtkötter, Olaf; Brenneisen, Peter

    2014-06-01

    Currently, the oxidative stress (or free radical) theory of aging is the most popular explanation of how aging occurs at the molecular level. Accordingly, a stress-induced senescence-like phenotype of human dermal fibroblasts can be induced in vitro by the exposure of human diploid fibroblasts to subcytotoxic concentrations of hydrogen peroxide. However, several biomarkers of replicative senescence e.g. cell cycle arrest and enlarged morphology are abrogated 14 days after treatment, indicating that reactive oxygen species (ROS) rather acts as a trigger for short-term senescence (1-3 days) than being responsible for the maintenance of the senescence-like phenotype. Further, DNA-damaging factors are discussed resulting in a permanent senescent cell type. To induce long-term premature senescence and to understand the molecular alterations occurring during the aging process, we analyzed mitomycin C (MMC) as an alkylating DNA-damaging agent and ROS producer. Human dermal fibroblasts (HDF), used as model for skin aging, were exposed to non-cytotoxic concentrations of MMC and analyzed for potential markers of cellular aging, for example enlarged morphology, activity of senescence-associated-ß-galactosidase, cell cycle arrest, increased ROS production and MMP1-activity, which are well-documented for HDF in replicative senescence. Our data show that mitomycin C treatment results in a drug-induced accelerated senescence (DIAS) with long-term expression of senescence markers, demonstrating that a combination of different susceptibility factors, here ROS and DNA alkylation, are necessary to induce a permanent senescent cell type.

  20. Density Changes in Plutonium Observed from Accelerated Aging using Pu-238 Enrichment

    SciTech Connect

    Chung, B W; Thompson, S R; Woods, C H; Hopkins, D J; Gourdin, W H; Ebbinghaus, B B

    2003-12-19

    Plutonium, because of its radioactive nature, ages from the ''inside out'' by means of self-irradiation damage and thus produces Frankel-type defects (vacancies and self-interstitial atoms) and defect clusters. The self-irradiation damage in Plutonium-239 occurs mainly by {alpha}-particle decay, where most of the damage comes from the U-235 recoil nucleus. The defects resulting from the residual lattice damage and helium in-growth could result in microstructural and physical property changes. Because these self-irradiation effects would normally require decades to measure, with a fraction (7.5 wt%) of Pu-238 is added to the reference plutonium alloy thus accelerating the aging process by approximately 18 times the normal rate. By monitoring the properties of the Pu-238 spiked alloy over a period of about 3.5 years, the properties of plutonium in storage can be projected for periods up to about 60 years. This paper presents density and volume changes observed from the immersion density and dilatometry measurements equivalent to aging the reference plutonium alloys to nine years.

  1. Disparity between online and offline tests in accelerated aging tests of LED lamps under electric stress.

    PubMed

    Wang, Yao; Jing, Lei; Ke, Hong-Liang; Hao, Jian; Gao, Qun; Wang, Xiao-Xun; Sun, Qiang; Xu, Zhi-Jun

    2016-09-20

    The accelerated aging tests under electric stress for one type of LED lamp are conducted, and the differences between online and offline tests of the degradation of luminous flux are studied in this paper. The transformation of the two test modes is achieved with an adjustable AC voltage stabilized power source. Experimental results show that the exponential fitting of the luminous flux degradation in online tests possesses a higher fitting degree for most lamps, and the degradation rate of the luminous flux by online tests is always lower than that by offline tests. Bayes estimation and Weibull distribution are used to calculate the failure probabilities under the accelerated voltages, and then the reliability of the lamps under rated voltage of 220 V is estimated by use of the inverse power law model. Results show that the relative error of the lifetime estimation by offline tests increases as the failure probability decreases, and it cannot be neglected when the failure probability is less than 1%. The relative errors of lifetime estimation are 7.9%, 5.8%, 4.2%, and 3.5%, at the failure probabilities of 0.1%, 1%, 5%, and 10%, respectively. PMID:27661576

  2. ACCELERATED-AGING OF SHIPPING PACKAGE O-RINGS FOR PU STORAGE

    SciTech Connect

    Hoffman, E

    2008-01-10

    The Savannah River Site (SRS) is storing surplus plutonium (Pu) materials in the K-Area Materials Storage (KAMS) facility. The Pu materials are packaged per the DOE 3013 Standard. The nested, welded 300 series stainless steel 3013 containers are transported to KAMS in Type B shipping packages and subsequently stored in the same packages. These type B shipping packages consist of double containment vessels sealed with dual O-rings. The O-ring compound is Parker Seals V0835-75, based on Viton{reg_sign} GLT fluoroelastomer. This work evaluates the performance of the V0835-75 O-rings at accelerated-aging conditions. The results will be used to develop a lifetime prediction model for O-rings in KAMS.

  3. Comparative Study on Accelerated Thermal Ageing of Vegetable Insulating Oil-paperboard and Mineral Oil-paperboard

    NASA Astrophysics Data System (ADS)

    Zhou, Zhu-Jun; Hu, Ting; Cheng, Lin; Tian, Kai; Yang, Jun; Wang, Xuan; Fang, Fu-Xin; Kong, Hai-Yang; Qian, Hang

    2016-05-01

    To comparatively study the insulation ageing life of vegetable insulating oil-paperboard and mineral oil-paperboard, we conducted accelerated thermal ageing experiments at 170°C. Then according to the temperature rise of vegetable insulating oil transformer, we conducted accelerated thermal ageing experiments at 150°C for vegetable insulating oil-paperboard and at 140°C for mineral oil-paperboard. The appearance, polymerization degree, and SEM microstructure of the paperboard after different ageing experiments were comparative analyzed. The results show that after the oil-paperboard system is accelerated ageing for 1 000 h at 170°C, that is equivalent to 20 years natural ageing, the structure of paperboard in vegetable insulating oil is damaged severely, which indicates that the lifetime of transformer are in the late stage; while the structure of paperboard in mineral oil maintain complete, and the polymerization degree is still above 500, which indicate that the lifetime of transformer are in the middle stage. The accelerated ageing rate of the vegetable insulating oil-paperboard system at 150°C is slower than that of the mineral oil-paperboard system, which indicates that the lifetime of the vegetable insulating oil-paperboard is longer than that of the mineral oil-paperboard.

  4. Effect of disinfection and accelerated ageing on dimensional stability and detail reproduction of a facial silicone with nanoparticles.

    PubMed

    Pesqueira, A A; Goiato, M C; Dos Santos, D M; Haddad, M F; Moreno, A

    2012-05-01

    The aim of the present study was to evaluate the effect of disinfection and accelerated ageing on the dimensional stability and detail reproduction of a facial silicone with different types of nanoparticle. A total of 60 specimens were fabricated with Silastic MDX 4-4210 silicone and they were divided into three groups: colourless and pigmented with nanoparticles (make-up powder and ceramic powder). Half of the specimens of each group were disinfected with Efferdent tablets and half with neutral soap for 60 days. Afterwards, all specimens were subjected to accelerated ageing. Both dimensional stability and detail reproduction tests were performed after specimen fabrication (initial period), after chemical disinfection, and after accelerated ageing periods (252, 504 and 1008 hours). The dimensional stability test was conducted using AutoCAD software, while detail reproduction was analysed using a stereoscope magnifying glass. Dimensional stability values were statistically evaluated by analysis of variance (ANOVA) followed by Tukey's test (p < 0.01). Detail reproduction results were compared using a score. Chemical disinfection and also accelerated ageing affected the dimensional stability of the facial silicone with statistically significant results. The silicone's detail reproduction was not affected by these two factors regardless of nanoparticle type, disinfection and accelerated ageing.

  5. Effect of disinfection and accelerated ageing on dimensional stability and detail reproduction of a facial silicone with nanoparticles.

    PubMed

    Pesqueira, A A; Goiato, M C; Dos Santos, D M; Haddad, M F; Moreno, A

    2012-05-01

    The aim of the present study was to evaluate the effect of disinfection and accelerated ageing on the dimensional stability and detail reproduction of a facial silicone with different types of nanoparticle. A total of 60 specimens were fabricated with Silastic MDX 4-4210 silicone and they were divided into three groups: colourless and pigmented with nanoparticles (make-up powder and ceramic powder). Half of the specimens of each group were disinfected with Efferdent tablets and half with neutral soap for 60 days. Afterwards, all specimens were subjected to accelerated ageing. Both dimensional stability and detail reproduction tests were performed after specimen fabrication (initial period), after chemical disinfection, and after accelerated ageing periods (252, 504 and 1008 hours). The dimensional stability test was conducted using AutoCAD software, while detail reproduction was analysed using a stereoscope magnifying glass. Dimensional stability values were statistically evaluated by analysis of variance (ANOVA) followed by Tukey's test (p < 0.01). Detail reproduction results were compared using a score. Chemical disinfection and also accelerated ageing affected the dimensional stability of the facial silicone with statistically significant results. The silicone's detail reproduction was not affected by these two factors regardless of nanoparticle type, disinfection and accelerated ageing. PMID:22428808

  6. An Alpha and Theta Intensive and Short Neurofeedback Protocol for Healthy Aging Working-Memory Training

    PubMed Central

    Reis, Joana; Portugal, Ana Maria; Fernandes, Luís; Afonso, Nuno; Pereira, Mariana; Sousa, Nuno; Dias, Nuno S.

    2016-01-01

    The present study tested the effects of an intensive and short alpha and theta neurofeedback (NF) protocol in working memory (WM) performance in a healthy elder population and explored the effects of a multimodal approach, by supplementing NF with cognitive tasks. Participants were allocated to four groups: NF (N = 9); neurofeedback supplemented with cognitive training (NFCT) (N = 8); cognitive training (CT) (N = 7) and sham neurofeedback (Sham-NF) (N = 6). The intervention consisted in 30-min sessions for 8 days. The NF group presented post intervention increases of alpha and theta relative power as well as performance in the matrix rotation task. In addition, a successful up training of frontal theta showed positive correlation with an improvement of post-training alpha and a better performance in the matrix rotation task. The results presented herein suggest that an intensive and short NF protocol enables elders to learn alpha and theta self-modulation and already presents moderate improvements in cognition and basal EEG. Also, CT group showed moderate performance gains on the cognitive tasks used during the training sessions but no clear improvements on neurophysiology and behavioral measurements were observed. This study represents a first attempt to study the effects of an intensive and short NF protocol in WM performance of elders. The evidence presented here suggests that an intensive and short NF intervention could be a valid alternative for introduction of older populations to NF methodologies. PMID:27458369

  7. [Senescence-accelerated mouse (SAM): with special reference to age-associated pathologies and their modulation].

    PubMed

    Takeda, T

    1996-07-01

    The senescence-accelerated mouse (SAM) has been under development by our research team at Kyoto University since 1970 through selective inbreeding of the AKR/J strain of mice donated by the Jackson Laboratory in 1968, based on the data of the grading score of senescence, life span, and pathologic phenotypes. At present, there are 12 lines of SAM; the 9 senescence-prone inbred strains (SAMP) include SAMP1, SAMP2, SAMP3, SAMP6, SAMP7, SAMP8, SAMP9, SAMP10 and SAMP11, and the 3 senescence-resistant inbred strains (SAMR) SAMR1, SANR4 and SAMR5. Data from survival curves, the Gompertzian function and the grading score of senescence, together with growth patterns of body weight of these SAMP and SAMR mice revealed that the characteristic feature of aging common to all SAMP mice is "accelerated senescence": early onset and irreversible advance of senescence manifested by several signs and gross lesions such as the loss of normal behavior, various skin lesions, increased lordokyphosis, etc., after a period of normal development. Routine postmortem examinations and the pathobiological features revealed by systematically designed studies have shown several pathologic phenotypes, which are often characteristic enough to differentiate among the various SAM strains: senile amyloidosis in SAMP1, -P2, -P7, -P9, -P10 and -P11, secondary amyloidosis in SAMP2 and -P6, contracted kidney in SAMP1, -P2, -P10, -P11, immunoblastic lymphoma in SAMR1 and -R4, histiocytic sarcoma in SAMR1 and -R4, ovarian cysts in SAMR1, impaired immune response in SAMP1, -P2 and -P8, hyperinflation of the lungs in SAMP1, hearing impairment in SAMP1, degenerative temporomandibular joint disease in SAMP3, senile osteoporosis in SAMP6, deficits in learning and memory in SAMP8 and -P10, emotional disorders in SAMP8 and -P10, cataracts in SAMP9, and brain atrophy in SAMP10. These are all age-associated pathologies, the incidence and severity of which increase with advancing age. The SAM model in which these

  8. Age-related differences in acceleration, maximum running speed, and repeated-sprint performance in young soccer players.

    PubMed

    Mendez-Villanueva, Alberto; Buchheit, Martin; Kuitunen, Sami; Douglas, Andrew; Peltola, Esa; Bourdon, Pitre

    2011-03-01

    We investigated age-related differences in the relationships among acceleration, maximum running speed, and repeated-sprint performance in 61 highly trained young male soccer players (Under 14, n = 14; Under 16, n = 22; Under 18, n = 25). We also examined the possible influence of anthropometry (stature, body mass, fat-free mass) and biological maturation (age at peak height velocity) on performance in those three sprint-running qualities. Players were tested for 10-m sprint (acceleration), flying 20-m sprint (maximum running speed), and 10 × 30-m sprint (repeated-sprint performance) times. Correlations between acceleration, maximum running speed, and repeated-sprint performance were positive and large to almost perfect (r = 0.55-0.96), irrespective of age group. There were age-based differences both in absolute performance in the three sprint-running qualities (Under 18 > Under 16 > Under 14; P < 0.001) and when body mass and fat-free mass were statistically controlled (P < 0.05). In contrast, all between-group differences disappeared after adjustment for age at peak height velocity (P > 0.05). The large correlations among acceleration, maximum running speed, and repeated-sprint performance in all age groups, as well as the disappearance of between-group differences when adjusted for estimated biological maturity, suggest that these physical qualities in young highly trained soccer players might be considered as a general quality, which is likely to be related to qualitative adaptations that accompany maturation.

  9. Accelerated aging of solid lubricants for the W76-1 TSL : effects of polymer outgassing.

    SciTech Connect

    Dugger, Michael Thomas; Wallace, William O.; Huffman, Elizabeth M.

    2006-09-01

    The behavior of MoS{sub 2} lubricants intended for the W76-1 TSL was evaluated after 17 and 82 thermal cycles, each lasting seven days and including a low temperature of -35 C and a high temperature of 93 C, in a sealed container containing organic materials. The MoS{sub 2} was applied by tumbling with MoS{sub 2} powder and steel pins (harperized), or by spraying with a resin binder (AS Mix). Surface composition measurements indicated an uptake of carbon and silicon on the lubricant surfaces after aging. Oxidation of the MoS{sub 2} on harperized coupons, where enough MoS{sub 2} was present at the surface to result in significant Mo and S concentrations, was found to be minimal for the thermal cycles in an atmosphere of primarily nitrogen. Bare steel surfaces showed a reduction in friction for exposed coupons compared to control coupons stored in nitrogen, at least for the initial cycles of sliding until the adsorbed contaminants were worn away. Lubricated surfaces showed no more than a ten percent increase in steady-state friction coefficient after exposure. Initial coefficient of friction was up to 250 percent higher than steady-state for AS Mix films on H950 coupons after 82 thermal cycles. However, the friction coefficient exhibited by lubricated coupons was never greater than 0.25, and more often less than 0.15, even after the accelerated aging exposures.

  10. Color stability of modern composites subjected to different periods of accelerated artificial aging.

    PubMed

    Drubi-Filho, Brahim; Garcia, Lucas da Fonseca Roberti; Cruvinel, Diogo Rodrigues; Sousa, Ana Beatriz Silva; Pires-de-Souza, Fernanda de Carvalho Panzeri

    2012-01-01

    The aim of this study was to evaluate the color stability of composites subjected to different periods of accelerated artificial aging (AAA). A polytetrafluorethylene matrix (10 x 2 mm) was used to fabricate 24 test specimens of three different composites (n=8): Tetric Ceram (Ivoclar/Vivadent); Filtek P90 and Z250 (3M ESPE), shade A3. After light activation for 20 s (FlashLite 1401), polishing and initial color readout (Spectrophotometer PCB 687; BYK Gardner), the test specimens were subjected to AAA (C-UV; Comexim), in 8-h cycles: 4 h exposure to UV-B rays at 50°C and 4 h condensation at 50°C. At the end of each cycle, color readouts were taken and the test ended when the mean value of ΔE attained a level ≥3.30. Tetric Ceram presented alteration in ΔE equal to 3.33 in the first aging cycle. For Filtek P90 and Z250, two (ΔE=3.60) and four (ΔE=3.42) AAA cycles were necessary. After each cycle, there was a reduction of luminosity in all the samples (ΔL). It was concluded that a short period of AAA was sufficient to promote clinically unacceptable color alteration in composites, and that this alteration was material-dependent. PMID:23306237

  11. The effect of accelerated ageing on performance properties of addition type silicone biomaterials.

    PubMed

    Stathi, K; Tarantili, P A; Polyzois, G

    2010-05-01

    The UV-protection provided to addition type silicone elastomers by various colorants, such as conventional dry earth pigments, as well as the so called "functional or reactive" pigments, was investigated. Moreover, the effect of a UV light absorber and a silica filler was also explored. Under the experimental parameters of this work, the exposure of silicone to UV radiation resulted in some changes of the IR absorbance, thermal decomposition after 400 degrees C, T(g) and tensile properties, whereas the storage modulus of samples was not affected. The obtained spectroscopic data, as well as the results of TGA and storage modulus, were interpreted by assuming that chain scission takes place during aging, whereas the improvement of tensile strength allows the hypothesis of a post-curing process, initiated by UV radiation. Therefore, the increase of T(g) could partly be due to the above reason and, furthermore, to the contribution of a rearrangement of chain fragments within the free volume of the elastomeric material. Regarding the evaluation of various coloring agents used in this work, the obtained results show that dry pigments are more sensitive to accelerated ageing conditions in comparison with functional liquid pigments. Moreover, the hydrophobic character of silicone matrix is enhanced, with the addition of this type pigments because of the vinyl functional silanes groups present in their chemical structure. Finally, it should be noted that the incorporation of silica nanofiller did not seem to prevent the silicone elastomer from degradation upon UV irradiation, but showed a significant reinforcing effect.

  12. Color stability of modern composites subjected to different periods of accelerated artificial aging.

    PubMed

    Drubi-Filho, Brahim; Garcia, Lucas da Fonseca Roberti; Cruvinel, Diogo Rodrigues; Sousa, Ana Beatriz Silva; Pires-de-Souza, Fernanda de Carvalho Panzeri

    2012-01-01

    The aim of this study was to evaluate the color stability of composites subjected to different periods of accelerated artificial aging (AAA). A polytetrafluorethylene matrix (10 x 2 mm) was used to fabricate 24 test specimens of three different composites (n=8): Tetric Ceram (Ivoclar/Vivadent); Filtek P90 and Z250 (3M ESPE), shade A3. After light activation for 20 s (FlashLite 1401), polishing and initial color readout (Spectrophotometer PCB 687; BYK Gardner), the test specimens were subjected to AAA (C-UV; Comexim), in 8-h cycles: 4 h exposure to UV-B rays at 50°C and 4 h condensation at 50°C. At the end of each cycle, color readouts were taken and the test ended when the mean value of ΔE attained a level ≥3.30. Tetric Ceram presented alteration in ΔE equal to 3.33 in the first aging cycle. For Filtek P90 and Z250, two (ΔE=3.60) and four (ΔE=3.42) AAA cycles were necessary. After each cycle, there was a reduction of luminosity in all the samples (ΔL). It was concluded that a short period of AAA was sufficient to promote clinically unacceptable color alteration in composites, and that this alteration was material-dependent.

  13. Density Changes in Plutonium Observed from Accelerated Aging Using Pu-238 Enrichment

    SciTech Connect

    Chung, B W; Thompson, S R; Woods, C H; Hopkins, D J; Gourdin, W H; Ebbinghaus, B B

    2005-10-19

    In support of Stockpile Stewardship activities, accelerated aging tests on a plutonium alloy enriched with 7.3 atomic percentage of {sup 238}Pu is underway using dilatometry at 35, 50, and 65 C and immersion density measurements of material stored at 50 C. Changes in density are expected from radiation damage in the lattice and helium in-growth. After twenty-five equivalent years of aging, the dilatometry data shows that the alloys at 35 C have expanded in volume by 0.11% to 0.12% and have started to exhibit a near linear expansion behavior primarily caused by the helium accumulation. The average He-to-vacancy ratio from tested specimens was determined to be around 2.3. The model for the lattice damage and helium in-growth accurately represents the volume swelling at 35 C. The density converted from the dilatometry corresponds well to the decreasing density trend of reference plutonium alloys as a function of time.

  14. Density changes in plutonium observed from accelerated aging using Pu-238 enrichment

    NASA Astrophysics Data System (ADS)

    Chung, B. W.; Thompson, S. R.; Woods, C. H.; Hopkins, D. J.; Gourdin, W. H.; Ebbinghaus, B. B.

    2006-09-01

    In support of Stockpile Stewardship activities, accelerated aging tests on a plutonium alloy enriched with 7.3 at.% of 238Pu is underway using dilatometry at 35, 50, and 65 °C and immersion density measurements of materials stored at 50 °C. Changes in density are expected from radiation damage in the lattice and helium in-growth. After 25 equivalent years of aging, the dilatometry data shows that the alloys at 35 °C have expanded in volume by 0.11-0.12% and have started to exhibit a near linear expansion behavior primarily caused by the helium accumulation. The average He-to-vacancy ratio from tested specimens was determined to be around 2.55. The model for the lattice damage and helium in-growth accurately represents the volume swelling at 35 °C. The density converted from the dilatometry corresponds well to the decreasing density trend of reference plutonium alloys as a function of time.

  15. [Proteoglycan in Bruch's membrane of senescence accelerated mouse: localization and age-related changes].

    PubMed

    Takada, Y; Ohkuma, H; Ogata, N; Matsushima, M; Sugasawa, K; Uyama, M

    1994-05-01

    We demonstrated the distribution of sulfated proteoglycans in Bruch's membrane of Senescence Accelerated Mouse histochemically and ultrastructurally using cuprolinic blue in conjunction with specific enzyme treatments and nitrous acid digestion. Two kinds of proteoglycan filaments were observed in the inner and outer collagenous layers, i.e., small collagen fibril-associated filaments (11 nm in average length), and large filaments (32 nm in average length). Intermediate size filaments (25 nm in average length) were seen in the basement membranes of the retinal pigment epithelium and choriocapillaris. Chondroitinase AC treatment eliminated the staining of filaments in the collagenous layers (chondroitin sulfate). Chondroitinase ABC treatment also eliminated the staining of filaments in the collagenous layers (chondroitin sulfate and dermatan sulfate). Nitrous acid eliminated the staining of filaments in both basement membranes (heparan sulfate). Proteoglycans containing chondroitin sulfate and dermatan sulfate were associated uniquely with collagen fibrils. Heparan sulfate proteoglycans were associated with the basement membranes of the pigment epithelium and choriocapillaris. With aging, the thickness of the basement membrane of the choriocapillaris and the staining of the filaments in the basement membranes of the pigment epithelium and choriocapillaris (heparan sulfate proteoglycans) increased. Collagen fibers became disarranged and the staining of both filaments in the collagenous layers decreased. The results of the staining characteristics probably reflect the aging of Bruch's membrane.

  16. Accelerating neuronal aging in in vitro model brain disorders: a focus on reactive oxygen species

    PubMed Central

    Campos, Priscila Britto; Paulsen, Bruna S.; Rehen, Stevens K.

    2014-01-01

    In this review, we discuss insights gained through the use of stem cell preparations regarding the modeling of neurological diseases, the need for aging neurons derived from pluripotent stem cells to further advance the study of late-onset adult neurological diseases, and the extent to which mechanisms linked to the mismanagement of reactive oxygen species (ROS). The context of these issues can be revealed using the three disease states of Parkinson’s (PD), Alzheimer’s (AD), and schizophrenia, as considerable insights have been gained into these conditions through the use of stem cells in terms of disease etiologies and the role of oxidative stress. The latter subject is a primary area of interest of our group. After discussing the molecular models of accelerated aging, we highlight the role of ROS for the three diseases explored here. Importantly, we do not seek to provide an extensive account of all genetic mutations for each of the three disorders discussed in this review, but we aim instead to provide a conceptual framework that could maximize the gains from merging the approaches of stem cell microsystems and the study of oxidative stress in disease in order to optimize therapeutics and determine new molecular targets against oxidative stress that spare stem cell proliferation and development. PMID:25386139

  17. A higher oxidative status accelerates senescence and aggravates age-dependent disorders in SAMP strains of mice.

    PubMed

    Hosokawa, Masanori

    2002-11-01

    The SAM strain of mice is actually a group of related inbred strains consisting of series of SAMP (accelerated senescence-prone, short-lived) and SAMR (accelerated senescence-resistant, longer-lived) strains. Comparing with the SAMR strains, the SAMP strains of mice show a more accelerated senescence process, shorter lifespan, and an earlier onset and more rapid progress of age-associated pathological phenotypes similar to several geriatric disorders observed in humans, including senile osteoporosis, degenerative joint disease, age-related deficits in learning and memory, olfactory bulb and forebrain atrophy, presbycusis and retinal atrophy, senile amyloidosis, immunosenescence, senile lungs, and diffuse medial thickening of the aorta. The higher oxidative stress observed in the SAMP strains of mice are partly caused by mitochondrial dysfunction, and may be one cause of the senescence acceleration and age-dependent alterations in cell structure and function, including neuronal cell degeneration. This senescence acceleration is also observed during senescence/crisis in cultures of isolated fibroblast-like cells from SAMP strains of mice, and was associated with a hyperoxidative status. These observations suggest that the SAM strains are useful tools in the attempt to understand the mechanisms of age-dependent degeneration of cells and tissues, and their aggravation, and to develop clinical interventions. PMID:12470893

  18. Characteristics of age-related behavioral changes in senescence-accelerated mouse SAMP8 and SAMP10.

    PubMed

    Miyamoto, M

    1997-01-01

    Senescence-Accelerated Mouse (SAM), a murine model of accelerated senescence, has been established by Takeda et al. (1981). SAM consists of senescence-accelerated-prone mouse (SAMP) and senescence-accelerated-resistant mouse (SAMR), the latter of which shows normal aging characteristics. In 1991 there were eight different substrains in the P-series, which commonly exhibited accelerated aging with a shortened life span (Takeda et al., 1991). Among the P-series, we have found that SAMP8 mice show significant impairments in a variety of learning tasks when compared with SAMR1 mice (Miyamoto et al., 1986). Further studies suggest that SAMP8 exhibits an age-related emotional disorder characterized by reduced anxiety-like behavior (Miyamoto et al., 1992). On the other hand, it has been shown that SAMP10 exhibits brain atrophy and learning impairments in an avoidance task (Shimada et al., 1992, 1993). Here, characteristics of age-related deficits in learning and memory, changes in emotional behavior, and abnormality of circadian rhythms in SAMP8 and SAMP10 mice are described. In the experiments, SAMP8/Ta (SAMP8), SAMP10/(/)Ta (SAMP10) and SAMR1TA (SAMR1) reared under specific pathogen-free conditions at Takeda Chemical Industries were used. PMID:9088911

  19. Comparison of different low-temperature aging protocols: its effects on the mechanical behavior of Y-TZP ceramics.

    PubMed

    Pereira, G K R; Muller, C; Wandscher, V F; Rippe, M P; Kleverlaan, C J; Valandro, L F

    2016-07-01

    This study evaluated the effect of different protocols of low-temperature degradation simulation on the mechanical behavior (structural reliability and flexural strength), the surface topography (roughness), and phase transformation of a Y-TZP ceramic. Disc-shaped specimens (1.2mm×12mm, Lava Frame, 3M ESPE, Seefeld, Germany) were manufactured according to ISO:6872-2008 and divided (n=30) according to the aging protocol executed: "Ctrl" - as-sintered - without any treatment; "Dist Water" - stored at distilled water at 37°C for 365 days; "MC" mechanical cycling into two steps: First - 200N, 2.2Hz for 2.000.000 cycles, Second - 450N, 10Hz for 1.000.000 cycles; "Aut" - steam autoclave at 134°C, 2bar (200kPa) for 20h; "Aut+MC"- Aut and MC methods. Roughness analysis (μm) showed, for Ra parameter, higher statistically significant values for Ctrl 0.68 (0.27), while for Rz parameter, the highest values were observed for Ctrl 4.43(1.53) and Aut 2.24 (0.62). Surface topography analysis showed that none aging method promoted surface alterations when compared to control group. Phase transformation analysis showed that all aging methods promoted an increase in m-phase content (Ctrl: 0.94%, Dist Water: 20.73%, MC: 9.47%, Aut: 53.33% and Aut+MC: 61.91%). Weibull Analysis showed higher statistical characteristic strength values for Aut (1033.36MPa) and Dist Water (1053.76MPa). No aging method promoted deleterious impact either on the biaxial flexural strengths or on the structural reliabilities (Weibull moduli). Also, none of the aging methods promoted reduction of Y-TZP mechanical properties; thus the development of new methodologies and the association between mechanical stimuli and hydrothermal degradation should be considered to better understand the mechanism of low-temperature degradation. PMID:26921592

  20. Circadian disruption induced by light-at-night accelerates aging and promotes tumorigenesis in young but not in old rats

    PubMed Central

    Vinogradova, Irina A.; Anisimov, Vladimir N.; Bukalev, Andrey V.; Ilyukha, Viktor A.; Khizhkin, Evgeniy A.; Lotosh, Tatiana A.; Semenchenko, Anna V.; Zabezhinski, Mark A.

    2010-01-01

    We evaluated the effect of exposure to constant light started at the age of 1 month and at the age of 14 months on the survival, life span, tumorigenesis and age-related dynamics of antioxidant enzymes activity in various organs in comparison to the rats maintained at the standard (12:12 light/dark) light/dark regimen. We found that exposure to constant light started at the age of 1 month accelerated spontaneous tumorigenesis and shortened life span both in male and female rats as compared to the standard regimen. At the same time, the exposure to constant light started at the age of 14 months failed to influence survival of male and female rats. While delaying tumors in males, constant light accelerated tumors in females. We conclude that circadian disruption induced by light-at-night started at the age of 1 month accelerates aging and promotes tumorigenesis in rats, however failed affect survival when started at the age of 14 months. PMID:20354269

  1. Aging as accelerated accumulation of somatic variants: whole-genome sequencing of centenarian and middle-aged monozygotic twin pairs.

    PubMed

    Ye, Kai; Beekman, Marian; Lameijer, Eric-Wubbo; Zhang, Yanju; Moed, Matthijs H; van den Akker, Erik B; Deelen, Joris; Houwing-Duistermaat, Jeanine J; Kremer, Dennis; Anvar, Seyed Yahya; Laros, Jeroen F J; Jones, David; Raine, Keiran; Blackburne, Ben; Potluri, Shobha; Long, Quan; Guryev, Victor; van der Breggen, Ruud; Westendorp, Rudi G J; 't Hoen, Peter A C; den Dunnen, Johan; van Ommen, Gert Jan B; Willemsen, Gonneke; Pitts, Steven J; Cox, David R; Ning, Zemin; Boomsma, Dorret I; Slagboom, P Eline

    2013-12-01

    It has been postulated that aging is the consequence of an accelerated accumulation of somatic DNA mutations and that subsequent errors in the primary structure of proteins ultimately reach levels sufficient to affect organismal functions. The technical limitations of detecting somatic changes and the lack of insight about the minimum level of erroneous proteins to cause an error catastrophe hampered any firm conclusions on these theories. In this study, we sequenced the whole genome of DNA in whole blood of two pairs of monozygotic (MZ) twins, 40 and 100 years old, by two independent next-generation sequencing (NGS) platforms (Illumina and Complete Genomics). Potentially discordant single-base substitutions supported by both platforms were validated extensively by Sanger, Roche 454, and Ion Torrent sequencing. We demonstrate that the genomes of the two twin pairs are germ-line identical between co-twins, and that the genomes of the 100-year-old MZ twins are discerned by eight confirmed somatic single-base substitutions, five of which are within introns. Putative somatic variation between the 40-year-old twins was not confirmed in the validation phase. We conclude from this systematic effort that by using two independent NGS platforms, somatic single nucleotide substitutions can be detected, and that a century of life did not result in a large number of detectable somatic mutations in blood. The low number of somatic variants observed by using two NGS platforms might provide a framework for detecting disease-related somatic variants in phenotypically discordant MZ twins. PMID:24182360

  2. Applications of a hologram watermarking protocol: aging-aware biometric signature verification and time validity check with personal documents

    NASA Astrophysics Data System (ADS)

    Vielhauer, Claus; Croce Ferri, Lucilla

    2003-06-01

    Our paper addresses two issues of a biometric authentication algorithm for ID cardholders previously presented namely the security of the embedded reference data and the aging process of the biometric data. We describe a protocol that allows two levels of verification, combining a biometric hash technique based on handwritten signature and hologram watermarks with cryptographic signatures in a verification infrastructure. This infrastructure consists of a Trusted Central Public Authority (TCPA), which serves numerous Enrollment Stations (ES) in a secure environment. Each individual performs an enrollment at an ES, which provides the TCPA with the full biometric reference data and a document hash. The TCPA then calculates the authentication record (AR) with the biometric hash, a validity timestamp, and a document hash provided by the ES. The AR is then signed with a cryptographic signature function, initialized with the TCPA's private key and embedded in the ID card as a watermark. Authentication is performed at Verification Stations (VS), where the ID card will be scanned and the signed AR is retrieved from the watermark. Due to the timestamp mechanism and a two level biometric verification technique based on offline and online features, the AR can deal with the aging process of the biometric feature by forcing a re-enrollment of the user after expiry, making use of the ES infrastructure. We describe some attack scenarios and we illustrate the watermarking embedding, retrieval and dispute protocols, analyzing their requisites, advantages and disadvantages in relation to security requirements.

  3. Accelerated ageing of an EAF black slag by carbonation and percolation for long-term behaviour assessment.

    PubMed

    Gurtubay, L; Gallastegui, G; Elias, A; Rojo, N; Barona, A

    2014-07-01

    The efficient reuse of industrial by-products, such as the electric arc furnace (EAF) black slag, is still hindered by concern over their long-term behaviour in outdoor environments. The aim of this study was to develop an accelerated ageing method to simulate the long-term natural carbonation of EAF slag exposed to the elements. The degree of carbonation achieved in a freshly produced slag after accelerated ageing and in a slag used on a fifteen-year-old unpaved road was very similar. The influence of particle size on accelerated carbonation was assessed, with it being concluded that the slag sample with a particle size bigger than 5-6 mm underwent slight carbonation over time when it was exposed to CO2. The accelerated ageing procedure based on percolating a previously carbonated water solution through the slag column allowed gradual leaching with simulated acid rain, as well as providing information about the gradual and total chemical release from the slag. Three classification groups were established according to the release rate of the determined elements. The joint use of the accelerated carbonation method and the percolation test is proposed as a useful tool for environmental risk assessment concerning the long-term air exposure of EAF black slag.

  4. DeltaNp63alpha overexpression induces downregulation of Sirt1 and an accelerated aging phenotype in the mouse.

    PubMed

    Sommer, Matthias; Poliak, Nina; Upadhyay, Sunil; Ratovitski, Edward; Nelkin, Barry D; Donehower, Lawrence A; Sidransky, David

    2006-09-01

    p63 is highly expressed in the skin and appears to be an early marker of keratinocyte differentiation. To examine the role of p63 in vivo, we generated transgenic mice that overexpress deltaNp63alpha in the skin. These mice exhibited an accelerated aging phenotype in the skin characterized by striking wound healing defects, decreased skin thickness, decreased subcutaneous fat tissue, hair loss, and decreased cell proliferation. The accelerated skin aging was accompanied by a dramatic decrease in longevity of the mice. We found that aging in deltaNp63alpha transgenic mice and other mouse models correlated with levels of Sirt1, a mammalian SIR2 orthologue thought to extend the lifespan in lower species. Moreover, increased deltaNp63alpha expression induced cellular senescence that was rescued by Sirt1. Our data suggest that deltaNp63alpha levels may affect aging in mammals, at least in part, through regulation of Sirt1.

  5. Coffee Silverskin Extract Protects against Accelerated Aging Caused by Oxidative Agents.

    PubMed

    Iriondo-DeHond, Amaia; Martorell, Patricia; Genovés, Salvador; Ramón, Daniel; Stamatakis, Konstantinos; Fresno, Manuel; Molina, Antonio; Del Castillo, Maria Dolores

    2016-01-01

    Nowadays, coffee beans are almost exclusively used for the preparation of the beverage. The sustainability of coffee production can be achieved introducing new applications for the valorization of coffee by-products. Coffee silverskin is the by-product generated during roasting, and because of its powerful antioxidant capacity, coffee silverskin aqueous extract (CSE) may be used for other applications, such as antiaging cosmetics and dermaceutics. This study aims to contribute to the coffee sector's sustainability through the application of CSE to preserve skin health. Preclinical data regarding the antiaging properties of CSE employing human keratinocytes and Caenorhabditis elegans are collected during the present study. Accelerated aging was induced by tert-butyl hydroperoxide (t-BOOH) in HaCaT cells and by ultraviolet radiation C (UVC) in C. elegans. Results suggest that the tested concentrations of coffee extracts were not cytotoxic, and CSE 1 mg/mL gave resistance to skin cells when oxidative damage was induced by t-BOOH. On the other hand, nematodes treated with CSE (1 mg/mL) showed a significant increased longevity compared to those cultured on a standard diet. In conclusion, our results support the antiaging properties of the CSE and its great potential for improving skin health due to its antioxidant character associated with phenols among other bioactive compounds present in the botanical material. PMID:27258247

  6. Degradation mechanism of LiCoO2/mesocarbon microbeads battery based on accelerated aging tests

    NASA Astrophysics Data System (ADS)

    Guan, Ting; Zuo, Pengjian; Sun, Shun; Du, Chunyu; Zhang, Lingling; Cui, Yingzhi; Yang, Lijie; Gao, Yunzhi; Yin, Geping; Wang, Fuping

    2014-12-01

    A series of LiCoO2/mesocarbon microbeads (MCMB) commercial cells cycled at different rates (0.6C, 1.2C, 1.5C, 1.8C, 2.4C and 3.0C) are disassembled and the capacity fade mechanism is proposed by analyzing the structure, morphology and electrochemical performance evolution at the capacity retention of 95%, 90%, 85%, 80%. The capacity deterioration of the commercial cell is mainly caused by the decay of the reversible capacity of LiCoO2 cathode, the irreversible loss of active lithium and the lithium remaining in anode. The proportions of effects by the above three factors are calculated accurately. The consumption of the active lithium leads to a cell imbalance between the anode and the cathode. The electrochemical test results indicate that the capacity fade of the active materials at the low rate is more obvious than that at the high rate. The influence of the active lithium is gradually increscent with the increasing rate. The rate of 1.5C is the optimal value to accelerate the aging of the full cell by comparing the testing results at different capacity retentions in the specific condition of low charge/discharge rate and shallow depth of discharge.

  7. Composites Associated with Pulp-Protection Material: Color-Stability Analysis after Accelerated Artificial Aging

    PubMed Central

    Cruvinel, Diogo Rodrigues; Garcia, Lucas da Fonseca Roberti; Consani, Simonides; de Carvalho Panzeri Pires-de-Souza, Fernanda

    2010-01-01

    Objectives: This study assessed the color stability of two composites associated with two pulp protectors submitted to accelerated artificial aging (AAA). Methods: 60 test specimens were made with 0.5 mm of protection material (calcium hydroxide - CH or glass ionomer cement - GIC) and 2.5 mm of restoration material (Concept or QuixFil) and divided into 3 groups (n=10) according to the type of protection material/composite, and the control group (no protection). After polishing, color readings were obtained with a spectrophotometer (PCB 6807 Byk Gardner) before and after AAA for 384 hours, and L*, a*, and b* coordinates and total color variation (ΔE) were analyzed (2-way ANOVA, Bonferroni, α=05). Results: Composites placed on CH presented lower L* levels than those on GIC, which presented higher L* values than the control group and lower b* values than those of the CH group. The Concept composite presented higher ΔE levels for all groups, differing statistically from QuixFil, except when placed on GIC. Conclusions: It was concluded that the protection material could affect the color stability and AAA is a factor that enhances this effect, depending on the type of composite used. PMID:20046473

  8. Microstructure and mechanical properties of composite resins subjected to accelerated artificial aging.

    PubMed

    dos Reis, Andréa Cândido; de Castro, Denise Tornavoi; Schiavon, Marco Antônio; da Silva, Leandro Jardel; Agnelli, José Augusto Marcondes

    2013-01-01

    The aim of this study was to investigate the influence of accelerated artificial aging (AAA) on the microstructure and mechanical properties of the Filtek Z250, Filtek Supreme, 4 Seasons, Herculite, P60, Tetric Ceram, Charisma and Filtek Z100. composite resins. The composites were characterized by Fourier-transform Infrared spectroscopy (FTIR) and thermal analyses (Differential Scanning Calorimetry - DSC and Thermogravimetry - TG). The microstructure of the materials was examined by scanning electron microscopy. Surface hardness and compressive strength data of the resins were recorded and the mean values were analyzed statistically by ANOVA and Tukey's test (α=0.05). The results showed significant differences among the commercial brands for surface hardness (F=86.74, p<0.0001) and compressive strength (F=40.31, p<0.0001), but AAA did not affect the properties (surface hardness: F=0.39, p=0.53; compressive strength: F=2.82, p=0.09) of any of the composite resins. FTIR, DSC and TG analyses showed that resin polymerization was complete, and there were no differences between the spectra and thermal curve profiles of the materials obtained before and after AAA. TG confirmed the absence of volatile compounds and evidenced good thermal stability up to 200 °C, and similar amounts of residues were found in all resins evaluated before and after AAA. The AAA treatment did not significantly affect resin surface. Therefore, regardless of the resin brand, AAA did not influence the microstructure or the mechanical properties.

  9. Evaluation of stone durability using a combination of ultrasound, mechanical and accelerated aging tests

    NASA Astrophysics Data System (ADS)

    Molina, E.; Cultrone, G.; Sebastián, E.; Alonso, F. J.

    2013-06-01

    The durability of a rock when exposed to decay agents is an important criterion when assessing its quality as a building material. Our study focuses on six varieties of natural stone (two limestones, one dolostone, one travertine and two sandstones) that are widely used in both new and historical buildings. In order to assess their quality, we measured and characterized their dynamic elastic properties using ultrasounds, we measured their compressive strength using the uniaxial compression test and we evaluated their durability by means of accelerated aging tests (freeze-thaw and salt crystallization). In order to get a full picture of the decay suffered by the different stones, we determined the composition and amount of the clay fraction of the six stones. We also observed small fragments subjected to the salt crystallization test under an environmental scanning electron microscope to study any textural change and measured the changes of colour on the surface with a spectrophotometer. Finally, we analysed the pore system of the stones before and after their deterioration using mercury injection porosimetry. We then compared the results for the different stones and found that dolostone obtained the best results, while the two limestones proved to be the least durable and had the lowest compressive strength.

  10. Coffee Silverskin Extract Protects against Accelerated Aging Caused by Oxidative Agents.

    PubMed

    Iriondo-DeHond, Amaia; Martorell, Patricia; Genovés, Salvador; Ramón, Daniel; Stamatakis, Konstantinos; Fresno, Manuel; Molina, Antonio; Del Castillo, Maria Dolores

    2016-01-01

    Nowadays, coffee beans are almost exclusively used for the preparation of the beverage. The sustainability of coffee production can be achieved introducing new applications for the valorization of coffee by-products. Coffee silverskin is the by-product generated during roasting, and because of its powerful antioxidant capacity, coffee silverskin aqueous extract (CSE) may be used for other applications, such as antiaging cosmetics and dermaceutics. This study aims to contribute to the coffee sector's sustainability through the application of CSE to preserve skin health. Preclinical data regarding the antiaging properties of CSE employing human keratinocytes and Caenorhabditis elegans are collected during the present study. Accelerated aging was induced by tert-butyl hydroperoxide (t-BOOH) in HaCaT cells and by ultraviolet radiation C (UVC) in C. elegans. Results suggest that the tested concentrations of coffee extracts were not cytotoxic, and CSE 1 mg/mL gave resistance to skin cells when oxidative damage was induced by t-BOOH. On the other hand, nematodes treated with CSE (1 mg/mL) showed a significant increased longevity compared to those cultured on a standard diet. In conclusion, our results support the antiaging properties of the CSE and its great potential for improving skin health due to its antioxidant character associated with phenols among other bioactive compounds present in the botanical material.

  11. Accelerated Aging Experiments for Prognostics of Damage Growth in Composite Materials

    NASA Technical Reports Server (NTRS)

    Saxena, Abhinav; Goebel, Kai Frank; Larrosa, Cecilia C.; Janapati, Vishnuvardhan; Roy, Surajit; Chang, Fu-Kuo

    2011-01-01

    Composite structures are gaining importance for use in the aerospace industry. Compared to metallic structures their behavior is less well understood. This lack of understanding may pose constraints on their use. One possible way to deal with some of the risks associated with potential failure is to perform in-situ monitoring to detect precursors of failures. Prognostic algorithms can be used to predict impending failures. They require large amounts of training data to build and tune damage model for making useful predictions. One of the key aspects is to get confirmatory feedback from data as damage progresses. These kinds of data are rarely available from actual systems. The next possible resource to collect such data is an accelerated aging platform. To that end this paper describes a fatigue cycling experiment with the goal to stress carbon-carbon composite coupons with various layups. Piezoelectric disc sensors were used to periodically interrogate the system. Analysis showed distinct differences in the signatures of growing failures between data collected at conditions. Periodic X-radiographs were taken to assess the damage ground truth. Results after signal processing showed clear trends of damage growth that were correlated to damage assessed from the X-ray images.

  12. Age-dependent changes in lipid peroxide levels in peripheral organs, but not in brain, in senescence-accelerated mice.

    PubMed

    Matsugo, S; Kitagawa, T; Minami, S; Esashi, Y; Oomura, Y; Tokumaru, S; Kojo, S; Matsushima, K; Sasaki, K

    2000-01-01

    The tissue concentration of lipid peroxides was determined in the brain, heart, liver, lung and kidney of accelerated senescence-prone (SAMP-8) and -resistant (SAMR-1) mice at 3, 6 and 9 months of age by a method involving chemical derivatization and high performance liquid chromatography. The level of lipid peroxides in the brain did not show an age-dependent change, but at each age the brain level of lipid peroxides was significantly higher in SAMP-8 than in SAMR-1. In contrast, the lipid peroxide levels in the peripheral organs showed increases with aging in both strains, and they were significantly higher in SAMP-8 than in SAMR-1 at both 3 and 6 months of age (except at 3 months of age in the kidney). These results suggest that increased oxidative stress in the brain and peripheral organs is a cause of the senescence-related degeneration and impairments seen in SAMP-8. PMID:10643812

  13. A Shortened Barnes Maze Protocol Reveals Memory Deficits at 4-Months of Age in the Triple-Transgenic Mouse Model of Alzheimer's Disease

    PubMed Central

    Attar, Aida; Liu, Tingyu; Chan, Wai-Ting Coco; Hayes, Jane; Nejad, Mona; Lei, KaiChyuan; Bitan, Gal

    2013-01-01

    Alzheimer's disease is a progressive neurodegenerative disease that manifests as memory loss, cognitive dysfunction, and dementia. Animal models of Alzheimer's disease have been instrumental in understanding the underlying pathological mechanism and in evaluation of potential therapies. The triple transgenic (3×Tg) mouse model of AD is unique because it recapitulates both pathologic hallmarks of Alzheimer's disease - amyloid plaques and neurofibrillary tangles. The earliest cognitive deficits in this model have been shown at 6-m of age by most groups, necessitating aging of the mice to this age before initiating evaluation of the cognitive effects of therapies. To assess cognitive deficits in the 3×Tg mice, originally we employed a typical Barnes maze protocol of 15 training trials, but found no significant deficits in aged mice. Therefore, we shortened the protocol to include only 5 training trials to increase difficulty. We found cognitive deficits using this protocol using mainly measures from the probe day, rather than the training trials. This also decreased the effort involved with data analysis. We compared 3×Tg and wild-type mice at 4-m- and 15-m of age using both the original, long training, and the short training paradigms. We found that differences in learning between 3×Tg and wild-type mice disappeared after the 4th training trial. Measures of learning and memory on the probe day showed significant differences between 3×Tg and wild-type mice following the short, 5-training trial protocol but not the long, 15-training trial protocol. Importantly, we detected cognitive dysfunction already at 4-m of age in 3×Tg mice using the short Barnes-maze protocol. The ability to test learning and memory in 4-m old 3×Tg mice using a shortened Barnes maze protocol offers considerable time and cost savings and provides support for the utilization of this model at pre-pathology stages for therapeutic studies. PMID:24236177

  14. Exposure to omega-3 fatty acids at early age accelerate bone growth and improve bone quality.

    PubMed

    Koren, Netta; Simsa-Maziel, Stav; Shahar, Ron; Schwartz, Betty; Monsonego-Ornan, Efrat

    2014-06-01

    Omega-3 fatty acids (FAs) are essential nutritional components that must be obtained from foods. Increasing evidence validate that omega-3 FAs are beneficial for bone health, and several mechanisms have been suggested to mediate their effects on bone, including alterations in calcium absorption and urinary calcium loss, prostaglandin synthesis, lipid oxidation, osteoblast formation and inhibition of osteoclastogenesis. However, to date, there is scant information regarding the effect of omega-3 FAs on the developing skeleton during the rapid growth phase. In this study we aim to evaluate the effect of exposure to high levels of omega-3 FAs on bone development and quality during prenatal and early postnatal period. For this purpose, we used the fat-1 transgenic mice that have the ability to convert omega-6 to omega-3 fatty acids and the ATDC5 chondrogenic cell line as models. We show that exposure to high concentrations of omega-3 FAs at a young age accelerates bone growth through alterations of the growth plate, associated with increased chondrocyte proliferation and differentiation. We further propose that those effects are mediated by the receptors G-protein coupled receptor 120 (GPR120) and hepatic nuclear factor 4α, which are expressed by chondrocytes in culture. Additionally, using a combined study on the structural and mechanical bone parameters, we show that high omega-3 levels contribute to superior trabecular and cortical structure, as well as to stiffer bones and improved bone quality. Most interestingly, the fat-1 model allowed us to demonstrate the role of maternal high omega-3 concentration on bone growth during the gestation and postnatal period.

  15. Hypothalamic leptin gene therapy reduces body weight without accelerating age-related bone loss.

    PubMed

    Turner, Russell T; Dube, Michael; Branscum, Adam J; Wong, Carmen P; Olson, Dawn A; Zhong, Xiaoying; Kweh, Mercedes F; Larkin, Iske V; Wronski, Thomas J; Rosen, Clifford J; Kalra, Satya P; Iwaniec, Urszula T

    2015-12-01

    Excessive weight gain in adults is associated with a variety of negative health outcomes. Unfortunately, dieting, exercise, and pharmacological interventions have had limited long-term success in weight control and can result in detrimental side effects, including accelerating age-related cancellous bone loss. We investigated the efficacy of using hypothalamic leptin gene therapy as an alternative method for reducing weight in skeletally-mature (9 months old) female rats and determined the impact of leptin-induced weight loss on bone mass, density, and microarchitecture, and serum biomarkers of bone turnover (CTx and osteocalcin). Rats were implanted with cannulae in the 3rd ventricle of the hypothalamus and injected with either recombinant adeno-associated virus encoding the gene for rat leptin (rAAV-Leptin, n=7) or a control vector encoding green fluorescent protein (rAAV-GFP, n=10) and sacrificed 18 weeks later. A baseline control group (n=7) was sacrificed at vector administration. rAAV-Leptin-treated rats lost weight (-4±2%) while rAAV-GFP-treated rats gained weight (14±2%) during the study. At study termination, rAAV-Leptin-treated rats weighed 17% less than rAAV-GFP-treated rats and had lower abdominal white adipose tissue weight (-80%), serum leptin (-77%), and serum IGF1 (-34%). Cancellous bone volume fraction in distal femur metaphysis and epiphysis, and in lumbar vertebra tended to be lower (P<0.1) in rAAV-GFP-treated rats (13.5 months old) compared to baseline control rats (9 months old). Significant differences in cancellous bone or biomarkers of bone turnover were not detected between rAAV-Leptin and rAAV-GFP rats. In summary, rAAV-Leptin-treated rats maintained a lower body weight compared to baseline and rAAV-GFP-treated rats with minimal effects on bone mass, density, microarchitecture, or biochemical markers of bone turnover.

  16. Poor maternal nutrition and accelerated postnatal growth induces an accelerated aging phenotype and oxidative stress in skeletal muscle of male rats

    PubMed Central

    Fernandez-Twinn, Denise S.; Chen, Jian Hua; Hargreaves, Iain P.; Neergheen, Viruna; Aiken, Catherine E.; Ozanne, Susan E.

    2016-01-01

    ABSTRACT ‘Developmental programming’, which occurs as a consequence of suboptimal in utero and early environments, can be associated with metabolic dysfunction in later life, including an increased incidence of cardiovascular disease and type 2 diabetes, and predisposition of older men to sarcopenia. However, the molecular mechanisms underpinning these associations are poorly understood. Many conditions associated with developmental programming are also known to be associated with the aging process. We therefore utilized our well-established rat model of low birth weight and accelerated postnatal catch-up growth (termed ‘recuperated’) in this study to establish the effects of suboptimal maternal nutrition on age-associated factors in skeletal muscle. We demonstrated accelerated telomere shortening (a robust marker of cellular aging) as evidenced by a reduced frequency of long telomeres (48.5-8.6 kb) and an increased frequency of short telomeres (4.2-1.3 kb) in vastus lateralis muscle from aged recuperated offspring compared to controls. This was associated with increased protein expression of the DNA-damage-repair marker 8-oxoguanine-glycosylase (OGG1) in recuperated offspring. Recuperated animals also demonstrated an oxidative stress phenotype, with decreased citrate synthase activity, increased electron-transport-complex activities of complex I, complex II-III and complex IV (all markers of functional mitochondria), and increased xanthine oxidase (XO), p67phox and nuclear-factor kappa-light-chain-enhancer of activated B-cells (NF-κB). Recuperated offspring also demonstrated increased antioxidant defense capacity, with increased protein expression of manganese superoxide dismutase (MnSOD), copper-zinc superoxide dismutase (CuZnSOD), catalase and heme oxygenase-1 (HO1), all of which are known targets of NF-κB and can be upregulated as a consequence of oxidative stress. Recuperated offspring also had a pro-inflammatory phenotype, as evidenced by

  17. e-Health Interventions for Healthy Aging: A Systematic Review Protocol.

    PubMed

    Gagnon, Marie-Pierre; Beogo, Idrissa; Buyl, Ronald

    2016-01-01

    e-Health interventions could contribute to healthy aging (HA) but their effectiveness has not been synthesised. This study aims to systematically review the effectiveness of e-health interventions for supporting HA. We will perform standardized searches to identify experimental and quasi-experimental studies evaluating the effectiveness of e-health interventions for HA. Outcomes of interest are: wellbeing, quality of life, activities of daily living, leisure activities, knowledge, evaluation of care, social support, skill acquisition and healthy behaviours. We will also consider adverse effects such as social isolation, anxiety, and burden on informal caregivers. Two reviewers will independently assess studies for inclusion and extract data using a standardised tool. We will calculate effect sizes related to e-health interventions. If not possible, we will present the findings in a narrative form. This systematic review will provide unique knowledge on the effectiveness of e-health interventions for supporting HA. PMID:27332428

  18. e-Health Interventions for Healthy Aging: A Systematic Review Protocol.

    PubMed

    Gagnon, Marie-Pierre; Beogo, Idrissa; Buyl, Ronald

    2016-01-01

    e-Health interventions could contribute to healthy aging (HA) but their effectiveness has not been synthesised. This study aims to systematically review the effectiveness of e-health interventions for supporting HA. We will perform standardized searches to identify experimental and quasi-experimental studies evaluating the effectiveness of e-health interventions for HA. Outcomes of interest are: wellbeing, quality of life, activities of daily living, leisure activities, knowledge, evaluation of care, social support, skill acquisition and healthy behaviours. We will also consider adverse effects such as social isolation, anxiety, and burden on informal caregivers. Two reviewers will independently assess studies for inclusion and extract data using a standardised tool. We will calculate effect sizes related to e-health interventions. If not possible, we will present the findings in a narrative form. This systematic review will provide unique knowledge on the effectiveness of e-health interventions for supporting HA.

  19. Experimental induction of type 2 diabetes in aging-accelerated mice triggered Alzheimer-like pathology and memory deficits.

    PubMed

    Mehla, Jogender; Chauhan, Balwantsinh C; Chauhan, Neelima B

    2014-01-01

    Alzheimer's disease (AD) is an age-dependent neurodegenerative disease constituting ~95% of late-onset non-familial/sporadic AD, and only ~5% accounting for early-onset familial AD. Availability of a pertinent model representing sporadic AD is essential for testing candidate therapies. Emerging evidence indicates a causal link between diabetes and AD. People with diabetes are >1.5-fold more likely to develop AD. Senescence-accelerated mouse model (SAMP8) of accelerated aging displays many features occurring early in AD. Given the role played by diabetes in the pre-disposition of AD, and the utility of SAMP8 non-transgenic mouse model of accelerated aging, we examined if high fat diet-induced experimental type 2 diabetes in SAMP8 mice will trigger pathological aging of the brain. Results showed that compared to non-diabetic SAMP8 mice, diabetic SAMP8 mice exhibited increased cerebral amyloid-β, dysregulated tau-phosphorylating glycogen synthase kinase 3β, reduced synaptophysin immunoreactivity, and displayed memory deficits, indicating Alzheimer-like changes. High fat diet-induced type 2 diabetic SAMP8 mice may represent the metabolic model of AD.

  20. Experimental Induction of Type 2 Diabetes in Aging-Accelerated Mice Triggered Alzheimer-Like Pathology and Memory Deficits

    PubMed Central

    Mehla, Jogender; Chauhan, Balwantsinh C.; Chauhan, Neelima B.

    2014-01-01

    Alzheimer’s disease (AD) is an age-dependent neurodegenerative disease constituting ~95% of late-onset non-familial/sporadic AD, and only ~5% accounting for early-onset familial AD. Availability of a pertinent model representing sporadic AD is essential for testing candidate therapies. Emerging evidence indicates a causal link between diabetes and AD. People with diabetes are >1.5-fold more likely to develop AD. Senescence-accelerated mouse model (SAMP8) of accelerated aging displays many features occurring early in AD. Given the role played by diabetes in the pre-disposition of AD, and the utility of SAMP8 non-transgenic mouse model of accelerated aging, we examined if high fat diet-induced experimental type 2 diabetes in SAMP8 mice will trigger pathological aging of the brain. Results showed that compared to non-diabetic SAMP8 mice, diabetic SAMP8 mice exhibited increased cerebral amyloid-β, dysregulated tau-phosphorylating glycogen synthase kinase 3β, reduced synaptophysin immunoreactivity, and displayed memory deficits, indicating Alzheimer-like changes. High fat diet-induced type 2 diabetic SAMP8 mice may represent the metabolic model of AD. PMID:24121970

  1. Multi-Directional Sprinting and Acceleration Phase in Basketball and Handball Players Aged 14 and 15 Years.

    PubMed

    Popowczak, Marek; Rokita, Andrzej; Struzik, Artur; Cichy, Ireneusz; Dudkowski, Andrzej; Chmura, Paweł

    2016-10-01

    An important role in handball and basketball is played by ability to accelerate and ability to repeat multiple sprints. The aim of the study was to assess level of ability in multi-directional sprinting and running time over the first 5 m of the 30 m sprint in 93 basketball and handball players (46 boys and 47 girls) aged 14 to 15 years. The attempts were also made to find the relationships between the time of a 5-m run to evaluate initial acceleration phase and multi-directional sprinting evaluated using Five-Time Shuttle Run To Gates Test Statistical analysis revealed no important differences in times of 5-m runs and times of multi-directional sprinting between groups with different ages, genders, and sports specialties. Furthermore, no significant correlations were found based on Spearman's rank correlation coefficient between times of 5-m run and multi-directional sprinting in the most of subgroups studied.

  2. Secular trend of the age at menarche of Japanese girls with special regard to the secular acceleration of the age at peak height velocity.

    PubMed

    Hoshi, H; Kouchi, M

    1981-12-01

    An attempt is made to clarify the special characteristics of the secular trend of the menarchial age in Japan. The relationships with the precocious appearance of the age at peak high velocity, another exemplification of the maturity acceleration, is also reviewed. This research on menarche was conducted in 1979-1980 on 284 school girls born between 1961 and 1966. The girls were healthy, of middle socioeconomic class, and grew up and lived in Tokyo and its outskirts. A questionnaire was given to each subject who was requested to answer after referring to her diary, mother's or sister's records, or any other writing about her menarche. If none of these was available, they were asked to provide an event which occurred soon before or after the menarche. The arithmetic mean of the age at menarche was 12.40 years with a range of 9.63 to 15.44 years. In 1958 research was conducted on the menarche of 309 girls in the same school, and the mean menarchial age was reported to be 13.27 years with a range of 10.83 to 16.92 years. The rate of acceleration during these 21 years was 4.4 months/decade. Mean menarchial ages obtained in 157 studies ever reported in Japan were plotted against the year of publication. No definite tendency was apparent until a gradual change toward earlier menstruation began in about 1920. In the next 20 years the average decreased from 15.0 to 14.2 years of age. The rate of decrease during the 1920-1940 period was about 4 months/decade. Due to World War 2, a retardation of menarche began in 1941 and reached a peak of about 15.0 years of age in 1950-1952, after which the trend changed into one of rapid acceleration. It is believed that the age at peak height velocity (PHV) is highly correlated with menarche age. The correlation coefficient is reported to be 0.71 by Nicholson and Hanly (1953), 0.93 by Deming (1957) and 0.77 by the author's of this study based on the present subjects. Thus it can be reasonably assumed that the secular trend of menarche

  3. Lifestyle-induced metabolic inflexibility and accelerated ageing syndrome: insulin resistance, friend or foe?

    PubMed Central

    Nunn, Alistair VW; Bell, Jimmy D; Guy, Geoffrey W

    2009-01-01

    determines functional longevity, a rather more descriptive term for the metabolic syndrome is the 'lifestyle-induced metabolic inflexibility and accelerated ageing syndrome'. Ultimately, thriftiness is good for us as long as we have hormetic stimuli; unfortunately, mankind is attempting to remove all hormetic (stressful) stimuli from his environment. PMID:19371409

  4. U. S. -French Cooperative Research Program: U. S. test results for cable insulation and jacket materials at the completion of accelerated aging

    SciTech Connect

    Bustard, L.D.

    1984-01-01

    Eight different U.S. insulation and jacket products have been accelerated aged at Sandia. The experimental variables included: (1) sequential versus simultaneous accelerated aging exposures; (2) the order of the sequential exposures; and (3) ambient versus 70/sup 0/C irradiation temperatures during sequential aging exposures. We observed that the irradiation temperature (70/sup 0/C or ambient) was secondary in importance to the choice of sequence for thermal and radiation aging. For most materials studied (except TEFZEL) the irradiation then thermal aging sequence was as severe or more severe than the thermal then irradiation aging sequence.

  5. Evaluation of Corneal Stromal Demarcation Line after Two Different Protocols of Accelerated Corneal Collagen Cross-Linking Procedures Using Anterior Segment Optical Coherence Tomography and Confocal Microscopy

    PubMed Central

    Ozgurhan, Engin Bilge; Sezgin Akcay, Betul Ilkay; Yildirim, Yusuf; Karatas, Gonul; Kurt, Tugba; Demirok, Ahmet

    2014-01-01

    Purpose. To evaluate the depth of corneal stromal demarcation line using AS-OCT and confocal microscopy after two different protocols of accelerated corneal collagen cross-linking procedures (CXL). Methods. Patients with keratoconus were divided into two groups. Peschke CXL device (Peschke CCL-VARIO Meditrade GmbH) applied UVA light with an intended irradiance of 18.0 mW/cm2 for 5 minutes after applying riboflavin for 20 minutes (group 1) and 30 minutes (group 2). One month postoperatively, corneal stromal demarcation line was measured using AS-OCT and confocal microscopy. Results. This study enrolled 34 eyes of 34 patients (17 eyes in group 1 and 17 eyes in group 2). The mean depth of the corneal stromal demarcation line was 208.64 ± 18.41 μm in group 1 and 240.37 ± 18.89 μm in group 2 measured with AS OCT, while it was 210.29 ± 18.66 μm in group 1 and 239.37 ± 20.07 μm in group 2 measured with confocal microscopy. Corneal stromal demarcation line depth measured with AS OCT or confocal microscopy was significantly deeper in group 2 than group 1 (P < 0.01). Conclusion. The group in which riboflavin was applied for 30 minutes showed significantly deeper corneal stromal demarcation line than the group in which riboflavin was applied for 20 minutes. PMID:25485145

  6. ISSLS PRIZE WINNER: INHIBITION OF NF-κB ACTIVITY AMELIORATES AGE-ASSOCIATED DISC DEGENERATION IN A MOUSE MODEL OF ACCELERATED AGING

    PubMed Central

    Nasto, Luigi A.; Seo, Hyoung-Yeon; Robinson, Andria R.; Tilstra, Jeremy S.; Clauson, Cheryl L.; Sowa, Gwendolyn A.; Ngo, Kevin; Dong, Qing; Pola, Enrico; Lee, Joon Y.; Niedernhofer, Laura J.; Kang, James D.; Robbins, Paul D.; Vo, Nam V.

    2012-01-01

    Study Design NF-κB activity was pharmacologically and genetically blocked in an accelerated aging mouse model to mitigate age-related disc degenerative changes. Objective To study the mediatory role of NF-κB signaling pathway in age-dependent intervertebral disc degeneration. Summary of Background Data Aging is a major contributor to intervertebral disc degeneration (IDD), but the molecular mechanism behind this process is poorly understood. NF-κB is a family of transcription factors which play a central role in mediating cellular response to damage, stress, and inflammation. Growing evidence implicates chronic NF-κB activation as a culprit in many aging-related diseases, but its role in aging-related IDD has not been adequately explored. We studied the effects of NF-κB inhibition on IDD using a DNA repair-deficient mouse model of accelerated aging (Ercc1-/Δ mice) previously been reported to exhibit age-related IDD. Methods Systemic inhibition of NF-κB activation was achieved either genetically by deletion of one allele of the NF-κB subunit p65 (Ercc1-/Δp65+/- mice) or pharmacologically by chronic intra-peritoneal administration of the Nemo Binding Domain (8K-NBD) peptide to block the formation of the upstream activator of NF-κB, IκB Inducible Kinase (IKK), in Ercc1-/Δ mice. Disc cellularity, total proteoglycan content and proteoglycan synthesis of treated mice and untreated controls were assessed. Results Decreased disc matrix proteoglycan content, a hallmark feature of IDD, and elevated disc NF-κB activity were observed in discs of progeroid Ercc1-/Δ mice and naturally aged wild-type compared to young WT mice. Systemic inhibition of NF-κB by the 8K-NBD peptide in Ercc1-/Δ mice increased disc proteoglycan synthesis and ameriolated loss disc cellularity and matrix proteoglycan. These results were confirmed genetically by using the p65 haploinsufficient Ercc1-/Δp65+/- mice. Conclusion These findings demonstrate that the IKK/NF-κB signaling pathway

  7. Methodology for designing accelerated aging tests for predicting life of photovoltaic arrays

    NASA Technical Reports Server (NTRS)

    Gaines, G. B.; Thomas, R. E.; Derringer, G. C.; Kistler, C. W.; Bigg, D. M.; Carmichael, D. C.

    1977-01-01

    A methodology for designing aging tests in which life prediction was paramount was developed. The methodology builds upon experience with regard to aging behavior in those material classes which are expected to be utilized as encapsulant elements, viz., glasses and polymers, and upon experience with the design of aging tests. The experiences were reviewed, and results are discussed in detail.

  8. DO BODY WEIGHT CHANGES IMPACT AGE OF PUBERTY AND REPRODUCTIVE ENDPOINTS IN THE EDSP TIER 1 MALE AND FEMALE PUBERTAL PROTOCOLS?

    EPA Science Inventory

    DO BODY WEIGHT CHANGES IMPACT AGE OF PUBERTY AND REPRODUCTIVE ENDPOINTS IN THE EDSP TIER 1 MALE AND FEMALE PUBERTAL PROTOCOLS? T.E. Stoker, K. McElroy, J. Ferrell, K. Bremser, R. Cooper and S.C. Laws. Endocrinology Branch, RTD, NHEERL, ORD, USEPA, RTP, NC.

    The relations...

  9. Deficiency in Poly(ADP-ribose) Polymerase-1 (PARP-1) Accelerates Aging and Spontaneous Carcinogenesis in Mice

    PubMed Central

    Piskunova, Tatiana S.; Yurova, Maria N.; Ovsyannikov, Anton I.; Semenchenko, Anna V.; Zabezhinski, Mark A.; Popovich, Irina G.; Wang, Zhao-Qi; Anisimov, Vladimir N.

    2008-01-01

    Genetic and biochemical studies have shown that PARP-1 and poly(ADP-ribosyl)ation play an important role in DNA repair, genomic stability, cell death, inflammation, telomere maintenance, and suppressing tumorigenesis, suggesting that the homeostasis of poly(ADP-ribosyl)ation and PARP-1 may also play an important role in aging. Here we show that PARP-1−/− mice exhibit a reduction of life span and a significant increase of population aging rate. Analysis of noninvasive parameters, including body weight gain, body temperature, estrous function, behavior, and a number of biochemical indices suggests the acceleration of biological aging in PARP-1−/− mice. The incidence of spontaneous tumors in both PARP-1−/− and PARP-1+/+ groups is similar; however, malignant tumors including uterine tumors, lung adenocarcinomas and hepatocellular carcinomas, develop at a significantly higher frequency in PARP-1−/− mice than PARP-1+/+ mice (72% and 49%, resp.; P < .05). In addition, spontaneous tumors appear earlier in PARP-1−/− mice compared to the wild type group. Histopathological studies revealed a wide spectrum of tumors in uterus, ovaries, liver, lungs, mammary gland, soft tissues, and lymphoid organs in both groups of the mice. These results demonstrate that inactivation of DNA repair gene PARP-1 in mice leads to acceleration of aging, shortened life span, and increased spontaneous carcinogenesis. PMID:19415146

  10. Age-related acceleration of endothelial dysfunction and subclinical atherosclerosis in subjects with coronary artery lesions after Kawasaki disease.

    PubMed

    Noto, Nobutaka; Okada, Tomoo; Karasawa, Kensuke; Ayusawa, Mamoru; Sumitomo, Naokata; Harada, Kensuke; Mugishima, Hideo

    2009-04-01

    The objective of this study was to test the hypothesis that accelerated endothelial dysfunction and the development of premature atherosclerosis are associated with age in subjects with coronary artery lesions after Kawasaki disease (KD). A case-control study was performed at a university hospital that included 35 post-KD subjects across a wide age range (range, 8-42 years) without traditional cardiovascular risk factors and 35 age- and sex-matched healthy control subjects (Cont). Flow-mediated dilatation (FMD) of the brachial artery-induced by reactive hyperemia, intima media thickness (IMT), and elastic modulus (Ep) of the common carotid artery were compared between KD and Cont subjects assessed against age. KD subjects had slightly higher levels of body mass index, lipid profile, and HbA1c than Cont subjects, but the differences were not significant. The mean IMT (p < 0.001), age-adjusted percentage normal IMT (%N IMT; p < 0.0001), and Ep (p < 0.001) were significantly higher in KD than Cont subjects, and the peak FMD% (p < 0.01) was significantly lower in KD than Cont subjects. There were significant correlations between FMD% and age (r = -0.51 p < 0.0001), IMT and age (r = 0.68, p < 0.001), and Ep and age (r = 0.58, p < 0.01) in KD but not Cont subjects. When the difference in FMD% between KD and matched Cont subjects (DeltaFMD%) was plotted against age, no significant relationship was found, although significant correlations between DeltaIMT and age (r = 0.52, p < 0.01) as well as between DeltaEp and age (r = 0.46, p < 0.05) were observed. When we defined values that were +2.0 SD over the mean control values (i.e., %N IMT >or= 120% and/or Ep >or= 50 kPa) as markers of subclinical atherosclerosis, 15 subjects met the criteria. Subjects over the age of 22 years were more likely to have (OR = 16.54, p = 0.0001) subclinical atherosclerosis in this cohort. Our results suggest that endothelial dysfunction and the development of premature atherosclerosis were

  11. Reliability and Failure Modes of Solid-State Lighting Electrical Drivers Subjected to Accelerated Aging

    SciTech Connect

    Lall, Pradeep; Sakalaukus, Peter; Davis, Lynn

    2015-02-19

    An investigation of an off-the-shelf solid-state lighting device with the primary focus on the accompanied light-emitting diode (LED) electrical driver (ED) has been conducted. A set of 10 EDs were exposed to temperature humidity life testing of 85% RH and 85 C (85/85) without an electrical bias per the JEDEC standard JESD22-A101C in order to accelerate the ingress of moisture into the aluminum electrolytic capacitor (AEC) and the EDs in order to assess the reliability of the LED drivers for harsh environment applications. The capacitance and equivalent series resistance for each AEC inside the ED were measured using a handheld LCR meter as possible leading indications of failure. The photometric quantities of a single pristine light engine were monitored in order to investigate the interaction between the light engine and the EDs. These parameters were used in assessing the overall reliability of the EDs. In addition, a comparative analysis has been conducted between the 85/85 accelerated test data and a previously published high-temperature storage life accelerated test of 135°C. The results of the 85/85 acceleration test and the comparative analysis are presented in this paper.

  12. Reliability and Failure Modes of Solid-State Lighting Electrical Drivers Subjected to Accelerated Aging

    DOE PAGES

    Lall, Pradeep; Sakalaukus, Peter; Davis, Lynn

    2015-02-19

    An investigation of an off-the-shelf solid-state lighting device with the primary focus on the accompanied light-emitting diode (LED) electrical driver (ED) has been conducted. A set of 10 EDs were exposed to temperature humidity life testing of 85% RH and 85 C (85/85) without an electrical bias per the JEDEC standard JESD22-A101C in order to accelerate the ingress of moisture into the aluminum electrolytic capacitor (AEC) and the EDs in order to assess the reliability of the LED drivers for harsh environment applications. The capacitance and equivalent series resistance for each AEC inside the ED were measured using a handheldmore » LCR meter as possible leading indications of failure. The photometric quantities of a single pristine light engine were monitored in order to investigate the interaction between the light engine and the EDs. These parameters were used in assessing the overall reliability of the EDs. In addition, a comparative analysis has been conducted between the 85/85 accelerated test data and a previously published high-temperature storage life accelerated test of 135°C. The results of the 85/85 acceleration test and the comparative analysis are presented in this paper.« less

  13. Development of a lifetime prediction model for lithium-ion batteries based on extended accelerated aging test data

    NASA Astrophysics Data System (ADS)

    Ecker, Madeleine; Gerschler, Jochen B.; Vogel, Jan; Käbitz, Stefan; Hust, Friedrich; Dechent, Philipp; Sauer, Dirk Uwe

    2012-10-01

    Battery lifetime prognosis is a key requirement for successful market introduction of electric and hybrid vehicles. This work aims at the development of a lifetime prediction approach based on an aging model for lithium-ion batteries. A multivariable analysis of a detailed series of accelerated lifetime experiments representing typical operating conditions in hybrid electric vehicle is presented. The impact of temperature and state of charge on impedance rise and capacity loss is quantified. The investigations are based on a high-power NMC/graphite lithium-ion battery with good cycle lifetime. The resulting mathematical functions are physically motivated by the occurring aging effects and are used for the parameterization of a semi-empirical aging model. An impedance-based electric-thermal model is coupled to the aging model to simulate the dynamic interaction between aging of the battery and the thermal as well as electric behavior. Based on these models different drive cycles and management strategies can be analyzed with regard to their impact on lifetime. It is an important tool for vehicle designers and for the implementation of business models. A key contribution of the paper is the parameterization of the aging model by experimental data, while aging simulation in the literature usually lacks a robust empirical foundation.

  14. Standard versus accelerated initiation of renal replacement therapy in acute kidney injury (STARRT-AKI): study protocol for a randomized controlled trial

    PubMed Central

    2013-01-01

    Background Acute kidney injury is a common and devastating complication of critical illness, for which renal replacement therapy is frequently needed to manage severe cases. While a recent systematic review suggested that “earlier” initiation of renal replacement therapy improves survival, completed trials are limited due to small size, single-centre status, and use of variable definitions to define “early” renal replacement therapy initiation. Methods/design This is an open-label pilot randomized controlled trial. One hundred critically ill patients with severe acute kidney injury will be randomly allocated 1:1 to receive “accelerated” initiation of renal replacement therapy or “standard” initiation at 12 centers across Canada. In the accelerated arm, participants will have a venous catheter placed and renal replacement therapy will be initiated within 12 hours of fulfilling eligibility. In the standard initiation arm, participants will be monitored over 7 days to identify indications for renal replacement therapy. For participants in the standard arm with persistent acute kidney injury, defined as a serum creatinine not declining >50% from the value at the time of eligibility, the initiation of RRT will be discouraged unless one or more of the following criteria are fulfilled: serum potassium ≥6.0 mmol/L; serum bicarbonate ≤10 mmol/L; severe respiratory failure (PaO2/FiO2<200) or persisting acute kidney injury for ≥72 hours after fulfilling eligibility. The inclusion criteria are designed to identify a population of critically ill adults with severe acute kidney injury who are likely to need renal replacement therapy during their hospitalization, but not immediately. The primary outcome is protocol adherence (>90%). Secondary outcomes include measures of feasibility (proportion of eligible patients enrolled in the trial, proportion of enrolled patients followed to 90 days for assessment of vital status and the need for renal replacement

  15. Accelerated wound closure of pressure ulcers in aged mice by chitosan scaffolds with and without bFGF.

    PubMed

    Park, Chan J; Clark, Sherrie G; Lichtensteiger, Carol A; Jamison, Russell D; Johnson, Amy J Wagoner

    2009-07-01

    Pressure ulcers are a significant healthcare concern, especially for elderly populations. Our work served to ameliorate the chronicity of these ulcers by addressing ischemia-reperfusion injury mediated by neutrophils and the concomitant loss of vasculature in these wounds. To this end, chitosan scaffolds loaded with basic fibroblast growth factor (bFGF) contained in gelatin microparticles were developed and tested for clinical relevance in an aged mouse model. Pressure ulcers were induced in aged mice, and efficacy of treatment was assessed. On days 3 and 7, both chitosan and chitosan-bFGF scaffolds significantly accelerated wound closure compared to gauze control. By day 10, all wounds achieved similar closure. Delivery and angiogenic function of bFGF was verified through ELISA and histology. Elevated neutrophil levels were observed in chitosan and chitosan-bFGF groups. Since neutrophil elastase contributes to the proteolytic environments of pressure ulcers, the effect of chitosan on elastase was assessed. In vitro, chitosan inhibited elastase activity. In vivo, elastase protein levels in wounds were reduced with chitosan-bFGF scaffolds by day 10. These results suggest that chitosan is an effective material for growth factor delivery and can help to heal chronic ulcers. Collectively, our data show that chitosan-bFGF scaffolds are effective in accelerating wound closure of pressure ulcers in aged animals.

  16. Analysis of tetragonal to monoclinic phase transformation caused by accelerated artificial aging and the effects of microstructure in stabilized zirconia

    NASA Astrophysics Data System (ADS)

    Lucas, Thomas J.

    This investigation addresses the issue that yttria stabilized zirconia is being used as a dental biomaterial without substantial evidence of its long-term viability. Furthermore, stabilized zirconia (SZ) undergoes low temperature degradation (LTD), which can lead to roughening of the surface. A rougher exterior can lead to increased wear of the antagonist in the oral environment. Despite the LTD concerns, SZ is now widely used in restorative dentistry, including full contour crowns. A comparison of aging methods to determine the role of artificial aging on inducing the transformation has not been extensively studied. Therefore, simulations of the transformation process were investigated by comparing different methods of accelerated aging. The rejected null hypothesis is that the temperature of aging treatment will not affect the time required to cause measurable monoclinic transformation of yttria stabilized zirconia. The transformation of SZ starts at the surface and progresses inward; however, it is unclear whether the progression is constant for different aging conditions. This investigation analyzed the depth of transformation as a function of aging conditions for stabilized zirconia in the top 5-6 mum from the surface. The rejected null hypothesis is that the transformation amount is constant throughout the first six micrometers from the surface. The effects of grain size on the amount of monoclinic transformation were also investigated. This study aimed to determine if the grain size of partially stabilized zirconia affects the amount of monoclinic transformation, surface roughness, and property degradation due to aging. The rejected null hypothesis is that the grain size will not affect the amount of monoclinic transformation, thus have no effect on surface roughening or property degradation. The final part of this study addresses the wear of enamel when opposing zirconia by observing how grain size and aging affected the wear rate of an enamel antagonist

  17. The Associative Changes in Scutellum Nuclear Content and Morphology with Viability Loss of Naturally Aged and Accelerated Aging Wheat (Triticum aestivum) Seeds

    PubMed Central

    Ahmed, Zaheer; Yang, Hui; Fu, Yong-Bi

    2016-01-01

    Timely prediction of seed viability loss over long-term storage represents a challenge in management and conservation of ex situ plant genetic resources. However, little attention has been paid to study the process of seed deterioration and seed aging signals under storage. An attempt was made here to investigate morphological and molecular changes in the scutellum and aleurone sections of naturally or artificially aged wheat seeds using TUNEL assay and DAPI staining. Twelve wheat genotypes or samples exposed to natural ageing (NA) or accelerated ageing (AA) were assayed and these samples had germination rates ranging from 11 to 93%. The assayed samples showed substantial changes in scutellum, but not aleurone. The nuclei observed in the majority of the scutellum cells of the NA seed samples of lower germination rates were longer in size and less visible, while the scutellum cell morphology or arrangement remained unchanged. In contrast, longer AA treatments resulted in the loss of scutellum cell structure, collapse of cell layers, and disappearance of honey comb arrangements. These nuclei and structural changes were consistent with the DNA assessments of nuclear alternations for the selected wheat samples. Interestingly, the sample seed germination loss was found to be associated with the reductions in the scutellum nuclear content and with the increases in the scutellum nuclei length to width ratio. These findings are significant for understanding the process of wheat seed deterioration and are also useful for searching for sensitive seed aging signals for developing tools to monitor seed viability under storage. PMID:27729925

  18. Microstructural modifications induced by accelerated aging and lipid absorption in remelted and annealed UHMWPEs for total hip arthroplasty.

    PubMed

    Puppulin, Leonardo; Zhu, Wenliang; Sugano, Nobuhiko; Pezzotti, Giuseppe

    2015-01-01

    Three types of commercially available ultra-high molecular weight polyethylene (UHMWPE) acetabular cups currently used in total hip arthroplasty have been studied by means of Raman micro-spectroscopy to unfold the microstructural modification induced by the oxidative degradation after accelerated aging with and without lipid absorption. The three investigated materials were produced by three different manufacturing procedures, as follows: irradiation followed by remelting, one-step irradiation followed by annealing, 3-step irradiation and annealing. Clear microstructural differences were observed in terms of phase contents (i.e. amorphous, crystalline and intermediate phase fraction). The three-step annealed material showed the highest crystallinity fraction in the bulk, while the remelted polyethylene is clearly characterized by the lowest content of crystalline phase and the highest content of amorphous phase. After accelerated aging either with or without lipids, the amount of amorphous phase decreased in all the samples as a consequence of the oxidation-induced recrystallization. The most remarkable variations of phase contents were detected in the remelted and in the single-step annealed materials. The presence of lipids triggered oxidative degradation especially in the remelted polyethylene. Such experimental evidence might be explained by the highest amount of amorphous phase in which lipids can be absorbed prior to accelerated aging. The results of these spectroscopic characterizations help to rationalize the complex effect of different irradiation and post-irradiation treatments on the UHMWPE microstructure and gives useful information on how significantly any single step of the manufacturing procedures might affect the oxidative degradation of the polymer.

  19. Quantitative proteomics analysis of specific protein expression and oxidative modification in aged senescence-accelerated-prone 8 mice brain.

    PubMed

    Poon, H F; Castegna, A; Farr, S A; Thongboonkerd, V; Lynn, B C; Banks, W A; Morley, J E; Klein, J B; Butterfield, D A

    2004-01-01

    The senescence-accelerated mouse (SAM) is a murine model of accelerated senescence that was established using phenotypic selection. The SAMP series includes nine substrains, each of which exhibits characteristic disorders. SAMP8 is known to exhibit age-dependent learning and memory deficits. In our previous study, we reported that brains from 12-month-old SAMP8 have greater protein oxidation, as well as lipid peroxidation, compared with brains from 4-month-old SAMP8 mice. In order to investigate the relation between age-associated oxidative stress on specific protein oxidation and age-related learning and memory deficits in SAMP8, we used proteomics to identify proteins that are expressed differently and/or modified oxidatively in aged SAMP8 brains. We report here that in 12 month SAMP8 mice brains the expressions of neurofilament triplet L protein, lactate dehydrogenase 2 (LDH-2), heat shock protein 86, and alpha-spectrin are significantly decreased, while the expression of triosephosphate isomerase (TPI) is increased compared with 4-month-old SAMP8 brains. We also report that the specific protein carbonyl levels of LDH-2, dihydropyrimidinase-like protein 2, alpha-spectrin and creatine kinase, are significantly increased in the brain of 12-month-old SAMP8 mice when compared with the 4-month-old SAMP8 brain. These findings are discussed in reference to the effect of specific protein oxidation and changes of expression on potential mechanisms of abnormal alterations in metabolism and neurochemicals, as well as to the learning and memory deficits in aged SAMP8 mice.

  20. Reduced quality and accelerated follicle loss with female reproductive aging - does decline in theca dehydroepiandrosterone (DHEA) underlie the problem?

    PubMed Central

    2013-01-01

    Infertility, spontaneous abortion and conception of trisomic offspring increase exponentially with age in mammals but in women there is an apparent acceleration in the rate from about age 37. The problems mostly commonly occur when the ovarian pool of follicles is depleted to a critical level with age but are also found in low follicular reserve of other etiologies. Since recent clinical studies have indicated that dehydroepiandrosterone (DHEA) supplementation may reverse the problem of oocyte quality, this review of the literature was undertaken in an attempt to find an explanation of why this is effective? In affected ovaries, oxygenation of follicular fluid is low, ultrastructural disturbances especially of mitochondria, occur in granulosa cells and oocytes, and considerable disturbances of meiosis occur. There is, however, no evidence to date that primordial follicles are compromised. In females with normal fertility, pre-antral ovarian theca cells respond to stimulation by inhibin B to provide androgen-based support for the developing follicle. With depletion of follicle numbers, inhibin B is reduced with consequent reduction in theca DHEA. Theca cells are the sole ovarian site of synthesis of DHEA, which is both a precursor of androstenedione and an essential ligand for peroxisome proliferator-activated receptor alpha (PPARα), the key promoter of genes affecting fatty acid metabolism and fat transport and genes critical to mitochondrial function. As well as inducing a plethora of deleterious changes in follicular cytoplasmic structure and function, the omega 9 palmitate/oleate ratio is increased by lowered activity of PPARα. This provides conditions for increased ceramide synthesis and follicular loss through ceramide-induced apoptosis is accelerated. In humans critical theca DHEA synthesis occurs at about 70 days prior to ovulation thus effective supplementation needs to be undertaken about four months prior to intended conception; timing which is also

  1. Accelerated aging studies of UHMWPE. II. Virgin UHMWPE is not immune to oxidative degradation.

    PubMed

    Edidin, A A; Villarraga, M L; Herr, M P; Muth, J; Yau, S S; Kurtz, S M

    2002-08-01

    In Part I of this series, we showed that aging at elevated oxygen pressure is more successful at increasing the depth to which degradation occurs although it, too, generally causes greater degradation at the surface than at the subsurface. Therefore we hypothesized that thermal degradation alone, in the absence of free radicals, could be sufficient to artificially age UHMWPE in a manner analogous to natural aging. In the present study, virgin and air-irradiated UHMWPE (extruded GUR 1050 and compression-molded 1900) were aged up to 4 weeks at elevated oxygen pressure, and the mechanical behavior at the surface and subsurface was examined. All the materials were substantially degraded following 4 weeks of aging, but the spatial variations in the nonirradiated materials more closely mimicked the previously observed subsurface peak of degradation seen in naturally aged UHMWPE following irradiation in air. This aged material could provide a more realistic model for subsurface mechanical degradation, making it suitable for further mechanical testing in venues such as wear simulation.

  2. Accelerated aging phenotype in mice with conditional deficiency for mitochondrial superoxide dismutase in the connective tissue.

    PubMed

    Treiber, Nicolai; Maity, Pallab; Singh, Karmveer; Kohn, Matthias; Keist, Alexander F; Ferchiu, Florentina; Sante, Lea; Frese, Sebastian; Bloch, Wilhelm; Kreppel, Florian; Kochanek, Stefan; Sindrilaru, Anca; Iben, Sebastian; Högel, Josef; Ohnmacht, Michael; Claes, Lutz E; Ignatius, Anita; Chung, Jin H; Lee, Min J; Kamenisch, York; Berneburg, Mark; Nikolaus, Thorsten; Braunstein, Kerstin; Sperfeld, Anne-Dorte; Ludolph, Albert C; Briviba, Karlis; Wlaschek, Meinhard; Florin, Lore; Angel, Peter; Scharffetter-Kochanek, Karin

    2011-04-01

    The free radical theory of aging postulates that the production of mitochondrial reactive oxygen species is the major determinant of aging and lifespan. Its role in aging of the connective tissue has not yet been established, even though the incidence of aging-related disorders in connective tissue-rich organs is high, causing major disability in the elderly. We have now addressed this question experimentally by creating mice with conditional deficiency of the mitochondrial manganese superoxide dismutase in fibroblasts and other mesenchyme-derived cells of connective tissues in all organs. Here, we have shown for the first time that the connective tissue-specific lack of superoxide anion detoxification in the mitochondria results in reduced lifespan and premature onset of aging-related phenotypes such as weight loss, skin atrophy, kyphosis (curvature of the spine), osteoporosis and muscle degeneration in mutant mice. Increase in p16(INK4a) , a robust in vivo marker for fibroblast aging, may contribute to the observed phenotype. This novel model is particularly suited to decipher the underlying mechanisms and to develop hopefully novel connective tissue-specific anti-aging strategies.

  3. Oxidative stress and age-related changes in T cells: is thalassemia a model of accelerated immune system aging?

    PubMed Central

    Ghatreh-Samani, Mahdi; Esmaeili, Nafiseh; Soleimani, Masoud; Asadi-Samani, Majid; Ghatreh-Samani, Keihan

    2016-01-01

    Iron overload in β-thalassemia major occurs mainly due to blood transfusion, an essential treatment for β-thalassemia major patients, which results in oxidative stress. It has been thought that oxidative stress causes elevation of immune system senescent cells. Under this condition, cells normally enhance in aging, which is referred to as premature immunosenescence. Because there is no animal model for immunosenescence, most knowledge on the immunosenescence pattern is based on induction of immunosenescence. In this review, we describe iron overload and oxidative stress in β-thalassemia major patients and how they make these patients a suitable human model for immunosenescence. We also consider oxidative stress in some kinds of chronic virus infections, which induce changes in the immune system similar to β-thalassemia major. In conclusion, a therapeutic approach used to improve the immune system in such chronic virus diseases, may change the immunosenescence state and make life conditions better for β-thalassemia major patients. PMID:27095931

  4. Oxidative stress and age-related changes in T cells: is thalassemia a model of accelerated immune system aging?

    PubMed

    Ghatreh-Samani, Mahdi; Esmaeili, Nafiseh; Soleimani, Masoud; Asadi-Samani, Majid; Ghatreh-Samani, Keihan; Shirzad, Hedayatolah

    2016-01-01

    Iron overload in β-thalassemia major occurs mainly due to blood transfusion, an essential treatment for β-thalassemia major patients, which results in oxidative stress. It has been thought that oxidative stress causes elevation of immune system senescent cells. Under this condition, cells normally enhance in aging, which is referred to as premature immunosenescence. Because there is no animal model for immunosenescence, most knowledge on the immunosenescence pattern is based on induction of immunosenescence. In this review, we describe iron overload and oxidative stress in β-thalassemia major patients and how they make these patients a suitable human model for immunosenescence. We also consider oxidative stress in some kinds of chronic virus infections, which induce changes in the immune system similar to β-thalassemia major. In conclusion, a therapeutic approach used to improve the immune system in such chronic virus diseases, may change the immunosenescence state and make life conditions better for β-thalassemia major patients.

  5. Analysis of Density Changes in Plutonium Observed from Accelerated Aging Using Pu-238 Enrichment

    SciTech Connect

    Chung, B W; Saw, C K; Thompson, S R; Quick, T M; Woods, C H; Hopkins, D J; Ebbinghaus, B B

    2006-07-11

    We present dimensional and density changes in an aging plutonium alloy enriched with 7.3 at.% of {sup 238}Pu and reference alloys of various ages. After 45 equivalent years of aging, the enriched alloys at 35 C have swelled in volume by 0.14 to 0.16% and now exhibit a near linear volume increase, without void swelling. Based on X-ray diffraction measurements, the lattice expansion by self-irradiation appears to be the primary cause for dimensional changes during the initial 2-3 years of aging. Following the initial transient, the density change is primarily cause by a constant helium in-growth rate as a result of {alpha}-particle decay.

  6. Ethylene propylene cable degradation during LOCA research tests: tensile properties at the completion of accelerated aging

    SciTech Connect

    Bustard, L.D.

    1982-05-01

    Six ethylene-propylene rubber (EPR) insulation materials were aged at elevated temperature and radiation stress exposures common in cable LOCA qualification tests. Material samples were subjected to various simultaneous and sequential aging simulations in preparation for accident environmental exposures. Tensile properties subsequent to the aging exposure sequences are reported. The tensile properties of some, but not all, specimens were sensitive to the order of radiation and elevated temperature stress exposure. Other specimens showed more severe degradation when simultaneously exposed to radiation and elevated temperature as opposed to the sequential exposure to the same stresses. Results illustrate the difficulty in defining a single test procedure for nuclear safety-related qualification of EPR elastomers. A common worst-case sequential aging sequence could not be identified.

  7. Accelerated Aging of BKC 44306-10 Rigid Polyurethane Foam: FT-IR Spectroscopy, Dimensional Analysis, and Micro Computed Tomography

    SciTech Connect

    Gilbertson, Robert D.; Patterson, Brian M.; Smith, Zachary

    2014-01-02

    An accelerated aging study of BKC 44306-10 rigid polyurethane foam was carried out. Foam samples were aged in a nitrogen atmosphere at three different temperatures: 50 °C, 65 °C, and 80 °C. Foam samples were periodically removed from the aging canisters at 1, 3, 6, 9, 12, and 15 month intervals when FT-IR spectroscopy, dimensional analysis, and mechanical testing experiments were performed. Micro Computed Tomography imaging was also employed to study the morphology of the foams. Over the course of the aging study the foams the decreased in size by a magnitude of 0.001 inches per inch of foam. Micro CT showed the heterogeneous nature of the foam structure likely resulting from flow effects during the molding process. The effect of aging on the compression and tensile strength of the foam was minor and no cause for concern. FT-IR spectroscopy was used to follow the foam chemistry. However, it was difficult to draw definitive conclusions about the changes in chemical nature of the materials due to large variability throughout the samples.

  8. Modulation of the phenolic composition and colour of red wines subjected to accelerated ageing by controlling process variables.

    PubMed

    González-Sáiz, J M; Esteban-Díez, I; Rodríguez-Tecedor, S; Pérez-Del-Notario, N; Arenzana-Rámila, I; Pizarro, C

    2014-12-15

    The aim of the present work was to evaluate the effect of the main factors conditioning accelerated ageing processes (oxygen dose, chip dose, wood origin, toasting degree and maceration time) on the phenolic and chromatic profiles of red wines by using a multivariate strategy based on experimental design methodology. The results obtained revealed that the concentrations of monomeric anthocyanins and flavan-3-ols could be modified through the application of particular experimental conditions. This fact was particularly remarkable since changes in phenolic profile were closely linked to changes observed in chromatic parameters. The main strength of this study lies in the possibility of using its conclusions as a basis to make wines with specific colour properties based on quality criteria. To our knowledge, the influence of such a large number of alternative ageing parameters on wine phenolic composition and chromatic attributes has not been studied previously using a comprehensive experimental design methodology.

  9. Towards A Model-Based Prognostics Methodology for Electrolytic Capacitors: A Case Study Based on Electrical Overstress Accelerated Aging

    NASA Technical Reports Server (NTRS)

    Celaya, Jose R.; Kulkarni, Chetan S.; Biswas, Gautam; Goebel, Kai

    2012-01-01

    A remaining useful life prediction methodology for electrolytic capacitors is presented. This methodology is based on the Kalman filter framework and an empirical degradation model. Electrolytic capacitors are used in several applications ranging from power supplies on critical avionics equipment to power drivers for electro-mechanical actuators. These devices are known for their comparatively low reliability and given their criticality in electronics subsystems they are a good candidate for component level prognostics and health management. Prognostics provides a way to assess remaining useful life of a capacitor based on its current state of health and its anticipated future usage and operational conditions. We present here also, experimental results of an accelerated aging test under electrical stresses. The data obtained in this test form the basis for a remaining life prediction algorithm where a model of the degradation process is suggested. This preliminary remaining life prediction algorithm serves as a demonstration of how prognostics methodologies could be used for electrolytic capacitors. In addition, the use degradation progression data from accelerated aging, provides an avenue for validation of applications of the Kalman filter based prognostics methods typically used for remaining useful life predictions in other applications.

  10. Mice deficient in Rbm38, a target of the p53 family, are susceptible to accelerated aging and spontaneous tumors

    PubMed Central

    Zhang, Jin; Xu, Enshun; Ren, Cong; Yan, Wensheng; Zhang, Min; Chen, Mingyi; Cardiff, Robert D.; Imai, Denise M.; Wisner, Erik; Chen, Xinbin

    2014-01-01

    RNA-binding motif protein 38 (Rbm38), also called RNPC1 [RNA-binding region (RNP1, RRM) containing 1], is a target of the p53 family and modulates p53 expression via mRNA translation. To investigate the biological function of Rbm38 in vivo, we generated an Rbm38-null mouse model. We showed that mice deficient in Rbm38 exhibit signs of accelerated aging and are prone to hematopoietic defects and spontaneous tumors. To determine the biological significance of the p53-Rbm38 loop, we showed that Rbm38 deficiency enhances accumulation of p53 induced by ionizing radiation (IR) and sensitizes mice to IR-induced lethality in a p53-dependent manner. Most importantly, Rbm38 deficiency markedly decreases the tumor penetrance in mice heterozygous for p53 via enhanced p53 expression. Interestingly, we found that Rbm38 deficiency shortens the life span of, and promotes lymphomagenesis in, mice deficient in p53. These results provide genetic evidence that Rbm38 is necessary for normal hematopoiesis and for suppressing accelerated aging and tumorigenesis. Thus, the p53-Rbm38 axis might be explored for extending longevity and for tumor suppression. PMID:25512531

  11. Multi-Directional Sprinting and Acceleration Phase in Basketball and Handball Players Aged 14 and 15 Years.

    PubMed

    Popowczak, Marek; Rokita, Andrzej; Struzik, Artur; Cichy, Ireneusz; Dudkowski, Andrzej; Chmura, Paweł

    2016-10-01

    An important role in handball and basketball is played by ability to accelerate and ability to repeat multiple sprints. The aim of the study was to assess level of ability in multi-directional sprinting and running time over the first 5 m of the 30 m sprint in 93 basketball and handball players (46 boys and 47 girls) aged 14 to 15 years. The attempts were also made to find the relationships between the time of a 5-m run to evaluate initial acceleration phase and multi-directional sprinting evaluated using Five-Time Shuttle Run To Gates Test Statistical analysis revealed no important differences in times of 5-m runs and times of multi-directional sprinting between groups with different ages, genders, and sports specialties. Furthermore, no significant correlations were found based on Spearman's rank correlation coefficient between times of 5-m run and multi-directional sprinting in the most of subgroups studied. PMID:27565172

  12. In silico analysis of gene expression profiles in the olfactory mucosae of aging senescence-accelerated mice.

    PubMed

    Getchell, Thomas V; Peng, Xuejun; Green, C Paul; Stromberg, Arnold J; Chen, Kuey-Chu; Mattson, Mark P; Getchell, Marilyn L

    2004-08-01

    We utilized high-density Affymetrix oligonucleotide arrays to investigate gene expression in the olfactory mucosae of near age-matched aging senescence-accelerated mice (SAM). The senescence-prone (SAMP) strain has a significantly shorter lifespan than does the senescence-resistant (SAMR) strain. To analyze our data, we applied biostatistical methods that included a correlation analysis to evaluate sources of methodologic and biological variability; a two-sided t-test to identify a subpopulation of Present genes with a biologically relevant P-value <0.05; and a false discovery rate (FDR) analysis adjusted to a stringent 5% level that yielded 127 genes with a P-value of <0.001 that were differentially regulated in near age-matched SAMPs (SAMP-Os; 13.75 months) compared to SAMRs (SAMR-Os, 12.5 months). Volcano plots related the variability in the mean hybridization signals as determined by the two-sided t-test to fold changes in gene expression. The genes were categorized into the six functional groups used previously in gene profiling experiments to identify candidate genes that may be relevant for senescence at the genomic and cellular levels in the aging mouse brain (Lee et al. [2000] Nat Genet 25:294-297) and in the olfactory mucosa (Getchell et al. [2003] Ageing Res Rev 2:211-243), which serves several functions that include chemosensory detection, immune barrier function, xenobiotic metabolism, and neurogenesis. Because SAMR-Os and SAMP-Os have substantially different median lifespans, we related the rate constant alpha in the Gompertz equation on aging to intrinsic as opposed to environmental mechanisms of senescence based on our analysis of genes modulated during aging in the olfactory mucosa. PMID:15248299

  13. Accelerated aging studies of UHMWPE. I. Effect of resin, processing, and radiation environment on resistance to mechanical degradation.

    PubMed

    Edidin, A A; Herr, M P; Villarraga, M L; Muth, J; Yau, S S; Kurtz, S M

    2002-08-01

    The resin and processing route have been identified as potential variables influencing the mechanical behavior, and hence the clinical performance, of ultra-high molecular weight polyethylene (UHMWPE) orthopedic components. Researchers have reported that components fabricated from 1900 resin may oxidize to a lesser extent than components fabricated from GUR resin during shelf aging after gamma sterilization in air. Conflicting reports on the oxidation resistance for 1900 raise the question of whether resin or manufacturing method, or an interaction between resin and manufacturing method, influences the mechanical behavior of UHMWPE. We conducted a series of accelerated aging studies (no aging, aging in oxygen or in nitrogen) to systematically examine the influence of resin (GUR or 1900), manufacturing method (bulk compression molding or extrusion), and sterilization method (none, in air, or in nitrogen) on the mechanical behavior of UHMWPE. The small punch testing technique was used to evaluate the mechanical behavior of the materials, and Fourier transform infrared spectroscopy was used to characterize the oxidation in selected samples. Our study showed that the sterilization environment, aging condition, and specimen location (surface or subsurface) significantly affected the mechanical behavior of UHMWPE. Each of the three polyethylenes evaluated seem to degrade according to a similar pathway after artificial aging in oxygen and gamma irradiation in air. The initial ability of the materials to exhibit post-yield strain hardening was significantly compromised by degradation. In general, there were only minor differences in the aging behavior of molded and extruded GUR 1050, whereas the molded 1900 material seemed to degrade slightly faster than either of the 1050 materials.

  14. Accelerating aging of zirconia femoral head implants: change of surface structure and mechanical properties.

    PubMed

    Chowdhury, S; Vohra, Yogesh K; Lemons, Jack E; Ueno, Masaru; Ikeda, Junji

    2007-05-01

    Recently, alternations of zirconia ceramic femoral heads of total hip prostheses during in vivo conditions have caused concern in the medical disciplines regarding phase transformation of zirconia prosthetic components. In this paper, we have investigated the mechanical and structural properties of different laboratory aged zirconia femoral heads and correlated changes in mechanical properties with the phase compositions of the sample. From laser microscope observation, cross-sectional Scanning electron microscopy imaging, and X-ray diffraction analysis on the surface of the zirconia femoral heads, we found monoclinic to tetragonal phase transformation in zirconia prostheses over time during the aging process in the laboratory. Mechanical properties, mainly hardness (H) and Young's modulus (E) values, were measured by nanoindentation technique on the surface of these implants. The results showed that both H and E values decreased with increased monoclinic phase in zirconia, thus confirming a phase transformation over time during aging.

  15. Influence of artificially accelerated ageing on the adhesive joint of plasma treated polymer materials

    NASA Astrophysics Data System (ADS)

    Lehocký, M.; Lapčik, L.; Dlabaja, R.; Rachünek, L.; Stoch, J.

    2004-03-01

    An influence of simulated ageing on the adhesive joint of plasma treated polyethylene (PE) and polypropylene (PP) was tested. Plasma surface treatment was performed in the rf-plasma reactor operating at 13,56 MHz. The simulated ageing of prepared specimens for following tensile testing was carried out under conditions given by Volkswagen standard P-VW 1200. Temperature of ageing was regularly oscillating between -40°C and 80°C (relative humidity 80%) for required time. The mechanical tensile properties of adhesive joint were measured according to the standard ISO 527. Surface analysis of treated polymer substrates was characterized by XPS measurement. The observation of surface structure and morphology was obtained using SEM. We used convenient cyanoacrylate adhesive Loctite E 406 for PE and PP joints. Tested adhesive joints were prepared in compliance with the standard ISO 4587.

  16. Physical properties of three maxillofacial materials as a function of accelerated aging.

    PubMed

    Dootz, E R; Koran, A; Craig, R G

    1994-04-01

    This study compares the tensile strength, elongation, Shore-A hardness, and tear resistance of three silicone maxillofacial materials before and after aging to provide comparative data for evaluation of new or experimental elastomers. The materials evaluated were MDX-4-4210, Factor II (A-2186), and Cosmesil. Tests were conducted 24 hours after specimen preparation and were repeated after aging for 900 hours in a Weather-Ometer device. Five samples were made for each material under all test conditions. After testing, mean values were calculated for all materials under all test conditions and were compared by two-way analysis of variance and Tukey intervals at p < or = 0.05.

  17. Exposure to radiation accelerates normal brain aging and produces deficits in spatial learning and memory

    NASA Astrophysics Data System (ADS)

    Shukitt-Hale, B.; Casadesus, G.; Carey, A.; Rabin, B. M.; Joseph, J. A.

    Previous studies have shown that radiation exposure, particularly to particles of high energy and charge (HZE particles), produces deficits in spatial learning and memory. These adverse behavioral effects are similar to those seen in aged animals. It is possible that these shared effects may be produced by the same mechanism; oxidative stress damage to the central nervous system caused by an increased release of reactive oxygen species is likely responsible for the deficits seen in aging and following irradiation. Both aged and irradiated rats display cognitive impairment in tests of spatial learning and memory such as the Morris water maze and the radial arm maze. These rats have decrements in the ability to build spatial representations of the environment and they utilize non-spatial strategies to solve tasks. Furthermore, they show a lack of spatial preference, due to a decline in the ability to process or retain place (position of a goal with reference to a "map" provided by the configuration of numerous cues in the environment) information. These declines in spatial memory occur in measures dependent on both reference and working memory, and in the flexibility to reset mental images. These results show that irradiation with high-energy particles produces age-like decrements in cognitive behavior that may impair the ability of astronauts to perform critical tasks during long-term space travel beyond the magnetosphere. Supported by NASA Grants NAG9-1190 and NAG9-1529

  18. Age-related trends in gene expression in the chemosensory-nasal mucosae of senescence-accelerated mice.

    PubMed

    Getchell, Thomas V; Peng, Xuejun; Stromberg, Arnold J; Chen, Kuey-Chu; Paul Green, C; Subhedar, Nishikant K; Shah, Dharmen S; Mattson, Mark P; Getchell, Marilyn L

    2003-04-01

    We have utilized high-density GeneChip oligonucleotide arrays to investigate the use of the senescence-accelerated mouse (SAM) as a biogerontological resource to identify patterns of gene expression in the chemosensory-nasal mucosa. Gene profiling in chronologically young and old mice of the senescence-resistant (SAMR) and senescence-prone (SAMP) strains revealed 133 known genes that were modulated by a three-fold or greater change either in one strain or the other or in both strains during aging. We also identified known genes in our study which based on their encoded proteins were identified as aging-related genes in the aging neocortex and cerebellum of mice as reported by Lee et al. (2000) [Nat. Genet. 25 (2000) 294]. Changes in gene profiles for chemosensory-related genes including olfactory and vomeronasal receptors, sensory transduction-associated proteins, and odor and pheromone transport molecules in the young SAMR and SAMP were compared with age-matched C57BL/6J mice. An analysis of known gene expression profiles suggests that changes in the expression of immune factor genes and genes associated with cell cycle progression and cell death were particularly prominent in the old SAM strains. A preliminary cellular validation study supported the dysregulation of cell cycle-related genes in the old SAM strains. The results of our initial study indicated that the use of the SAM models of aging could provide substantive information leading to a more fundamental understanding of the aging process in the chemosensory-nasal mucosa at the genomic, molecular, and cellular levels. PMID:12605961

  19. Target disruption of ribosomal protein pNO40 accelerates aging and impairs osteogenic differentiation of mesenchymal stem cells.

    PubMed

    Lin, Yen-Ming; Wu, Chih-Ching; Chang, Yu-Chen; Wu, Chu-Han; Ho, Hsien Li; Hu, Ji Wei; Chang, Ren-Chi; Wang, Chung-Ta; Ouyang, Pin

    2016-01-22

    pNO40/PS1D, a novel nucleolar protein, has been characterized as a core protein of eukaryotic 60S ribosome and at least two splicing forms of pNO40 mRNAs with alternative starting sites have been identified. Through production of knockout (ko) mice with either exon 2 (△E2), exon 4 (△E4) or △E2+E4 targeted disruption we identified a cryptic splicing product occurring in the ko tissues examined which in general cannot be observed in regular RT-PCR detection of wild-type (wt) animals. Among ko animals, △E4 null embryos exhibited prominent senescence-associated β-galactosidase (SA-β-gal) staining, a marker for senescent cells, in notochord, forelimbs and heart while bone marrow-derived mesenchymal stem cells (MSCs) from △E4 null mice developed accelerated aging and osteogenic differentiation defects compared to those from wt and other isoform mutant mice. Examination of the causal relationship between pNO40 deficiency and MSC-accelerated aging revealed △E4 null disruption in MSCs elicits high levels of ROS and elevated expression levels of p16 and Rb but not p53. Further analysis with iTraq identified CYP1B1, a component of the cytochrome p450 system, as a potential molecule mediating ROS generation in pNO40 deficient MSCs. We herein established a mouse model of MSC aging through pNO40-targeted depletion and demonstrated the effects of loss of pNO40 on bone homeostasis.

  20. Towards Prognostics of Power MOSFETs: Accelerated Aging and Precursors of Failure

    NASA Technical Reports Server (NTRS)

    Celaya, Jose R.; Saxena, Abhinav; Wysocki, Philip; Saha, Sankalita; Goebel, Kai

    2010-01-01

    This paper presents research results dealing with power MOSFETs (metal oxide semiconductor field effect transistor) within the prognostics and health management of electronics. Experimental results are presented for the identification of the on-resistance as a precursor to failure of devices with die-attach degradation as a failure mechanism. Devices are aged under power cycling in order to trigger die-attach damage. In situ measurements of key electrical and thermal parameters are collected throughout the aging process and further used for analysis and computation of the on-resistance parameter. Experimental results show that the devices experience die-attach damage and that the on-resistance captures the degradation process in such a way that it could be used for the development of prognostics algorithms (data-driven or physics-based).

  1. Inflammatory insult during pregnancy accelerates age-related behavioral and neurobiochemical changes in CD-1 mice.

    PubMed

    Li, Xue-Yan; Wang, Fang; Chen, Gui-Hai; Li, Xue-Wei; Yang, Qi-Gang; Cao, Lei; Yan, Wen-Wen

    2016-06-01

    Data shows that inflammation during pregnancy significantly exerts a long-term influence on offspring, such as increasing the risk of adult cognition decline in animals. However, it is unclear whether gestational inflammation affects the neurobehavioral and neurobiochemical outcomes in the mother-self during aging. In this study, pregnant CD-1 mice intraperitoneally received lipopolysaccharide (LPS) in two doses (25 and 50 g/kg, respectively) or normal saline daily during gestational days 15-17. At the age of 15 months, a battery of behavioral tasks was employed to evaluate their species-typical behaviors, sensorimotor ability, anxiety levels, and spatial learning and memory abilities. An immunohistochemical method was utilized preliminarily to detect neurobiochemical indicators consisting of amyloid-β, phosphorylated tau, presynaptic proteins synaptotagmin-1 and syntaxin-1, glial fibrillary acidic protein (GFAP), and histone-4 acetylation on the K8 site (H4K8ac). The behavioral results showed that LPS exposure during pregnancy exacerbated a decline in 15-month-old CD-1 mice's abilities to nest, their sensorimotor and spatial learning and memory capabilities, and increased their anxiety levels. The neurobiochemical results indicated that gestational LPS exposure also intensified age-related hippocampal changes, including increased amyloid-β42, phosphorylated tau, synaptotagmin-1 and GFAP, and decreased syntaxin-1 and H4K8ac. Our results suggested that the inflammatory insult during pregnancy could be an important risk factor for the development of Alzheimer's disease, and the H4K8 acetylation might play an important role in the underlying mechanism. This study offers a perspective for improving strategies that support healthy development and successful aging.

  2. Energy excess is the main cause of accelerated aging of mammals

    PubMed Central

    Biliński, Tomasz; Paszkiewicz, Tadeusz; Zadrag-Tecza, Renata

    2015-01-01

    The analysis of cases of unusually high longevity of naked mole rats and an alternative explanation of the phenomenon of calorie restriction effects in monkeys allowed for postulating that any factor preventing an excess of energy consumed, leads to increased lifespan, both in evolutionary and an individual lifetime scale. It is postulated that in mammals the most destructive processes resulting in shortening of life are not restricted to the phenomena explained by the hyperfunction theory of Mikhail Blagosklonny. Hyperfunction, understood as unnecessary or even adverse syntheses of cell components, can be to some extent prevented by lowered intake of nutrients when body growth ceases. We postulate also the contribution of glyco/lipotoxicity to aging, resulting from the excess of energy. Besides two other factors seem to participate in aging. One of them is lack of telomerase activity in some somatic cells. The second factor concerns epigenetic phenomena. Excessive activity of epigenetic maintenance system probably turns off some crucial organismal functions. Another epigenetic factor playing important role could be the micro RNA system deciding on expression of numerous age-related diseases. However, low extrinsic mortality from predation is a conditio sine qua non of the expression of all longevity phenotypes in animals. Among all long-lived animals, naked mole rats are unique in the elimination of neoplasia, which is accompanied by delayed functional symptoms of senescence. The question whether simultaneous disappearance of neoplasia and delayed senescence is accidental or not remains open. PMID:26079722

  3. Use of organic solderability preservatives on solderability retention of copper after accelerated aging

    SciTech Connect

    Hernandez, C.L.; Sorensen, N.R.; Lucero, S.J.

    1997-02-01

    Organic solderability preservatives (OSP`s) have been used by the electronics industry for some time to maintain the solderability of circuit boards and components. Since solderability affects both manufacturing efficiency and product reliability, there is significant interest in maintaining good solder wettability. There is often a considerable time interval between the initial fabrication of a circuit board or component and its use at the assembly level. Parts are often stored under a variety of conditions, in many cases not well controlled. Solder wettability can deteriorate during storage, especially in harsh environments. This paper describes the ongoing efforts at Sandia National Laboratories to quantify solder watability on bare and aged copper surfaces. Benzotriazole and imidazole were applied to electronic grade copper to retard aging effects on solderability. The coupons were introduced into Sandia`s Facility for Atmospheric Corrosion Testing (FACT) to simulate aging in a typical indoor industrial environment. H{sub 2}S, NO{sub 2} and Cl{sub 2} mixed gas was introduced into the test cell and maintained at 35{degrees}C and 70% relative humidity for test periods of one day to two weeks. The OSP`s generally performed better than bare Cu, although solderability diminished with increasing exposure times.

  4. Parkinson's disease accelerates age-related decline in haptic perception by altering somatosensory integration.

    PubMed

    Konczak, Jürgen; Sciutti, Alessandra; Avanzino, Laura; Squeri, Valentina; Gori, Monica; Masia, Lorenzo; Abbruzzese, Giovanni; Sandini, Giulio

    2012-11-01

    This study investigated how Parkinson's disease alters haptic perception and the underlying mechanisms of somatosensory and sensorimotor integration. Changes in haptic sensitivity and acuity (the abilities to detect and to discriminate between haptic stimuli) due to Parkinson's disease were systematically quantified and contrasted to the performance of healthy older and young adults. Using a robotic force environment, virtual contours of various curvatures were presented. Participants explored these contours with their hands and indicated verbally whether they could detect or discriminate between two contours. To understand what aspects of sensory or sensorimotor integration are altered by ageing and disease, we manipulated the sensorimotor aspect of the task: the robot either guided the hand along the contour or the participant actively moved the hand. Active exploration relies on multimodal sensory and sensorimotor integration, while passive guidance only requires sensory integration of proprioceptive and tactile information. The main findings of the study are as follows: first, a decline in haptic precision can already be observed in adults before the age of 70 years. Parkinson's disease may lead to an additional decrease in haptic sensitivity well beyond the levels typically seen in middle-aged and older adults. Second, the haptic deficit in Parkinson's disease is general in nature. It becomes manifest as a decrease in sensitivity and acuity (i.e. a smaller perceivable range and a diminished ability to discriminate between two perceivable haptic stimuli). Third, thresholds during both active and passive exploration are elevated, but not significantly different from each other. That is, active exploration did not enhance the haptic deficit when compared to passive hand motion. This implies that Parkinson's disease affects early stages of somatosensory integration that ultimately have an impact on processes of sensorimotor integration. Our results suggest that

  5. Deterioration of the Medial Olivocochlear Efferent System Accelerates Age-Related Hearing Loss in Pax2-Isl1 Transgenic Mice.

    PubMed

    Chumak, Tetyana; Bohuslavova, Romana; Macova, Iva; Dodd, Nicole; Buckiova, Daniela; Fritzsch, Bernd; Syka, Josef; Pavlinkova, Gabriela

    2016-05-01

    The development, maturation, and maintenance of the inner ear are governed by temporal and spatial expression cascades of transcription factors that form a gene regulatory network. ISLET1 (ISL1) may be one of the major players in this cascade, and in order to study its role in the regulation of inner ear development, we produced a transgenic mouse overexpressing Isl1 under the Pax2 promoter. Pax2-regulated ISL1 overexpression increases the embryonic ISL1(+) domain and induces accelerated nerve fiber extension and branching in E12.5 embryos. Despite these gains in early development, the overexpression of ISL1 impairs the maintenance and function of hair cells of the organ of Corti. Mutant mice exhibit hyperactivity, circling behavior, and progressive age-related decline in hearing functions, which is reflected in reduced otoacoustic emissions (DPOAEs) followed by elevated hearing thresholds. The reduction of the amplitude of DPOAEs in transgenic mice was first detected at 1 month of age. By 6-9 months of age, DPOAEs completely disappeared, suggesting a functional inefficiency of outer hair cells (OHCs). The timing of DPOAE reduction coincides with the onset of the deterioration of cochlear efferent terminals. In contrast to these effects on efferents, we only found a moderate loss of OHCs and spiral ganglion neurons. For the first time, our results show that the genetic alteration of the medial olivocochlear (MOC) efferent system induces an early onset of age-related hearing loss. Thus, the neurodegeneration of the MOC system could be a contributing factor to the pathology of age-related hearing loss.

  6. Mevastatin accelerates loss of synaptic proteins and neurite degeneration in aging cortical neurons in a heme-independent manner.

    PubMed

    Kannan, Madhuvanthi; Steinert, Joern R; Forsythe, Ian D; Smith, Andrew G; Chernova, Tatyana

    2010-09-01

    The therapeutic use of statins in reducing cholesterol requires careful assessment of potential neuroprotective and/or neurotoxic mechanisms. Chronic treatment with mevastatin (MV) exerts effects on cortical neuron morphology, protein expression and synaptic function in primary culture. MV impaired expression of synaptic proteins, reduced N-methyl-d-aspartate receptor (NMDAR) currents and accelerated neurodegeneration associated with aging. The down-regulating effect of MV on neuronal protein expression was additive with aging-associated decline in culture. Induction of Heme oxygenase-1 (HMOX1) by MV was superimposed on age-related up-regulation. Comparison of MV-treated and heme-deficient neurons showed that inhibition of heme synthesis (by succinyl acetone) had similar damaging effect on neurite integrity and MNDAR expression and function but not on expression of the receptor for neuropeptide Y1 (NPY1R). Replacement of heme in heme-deficient cultures restored protein expression but had no effect in those cultures co-treated with MV. Despite the dramatic induction of HMOX1, intracellular heme remained sufficient in MV-treated cultures, consistent with a heme-independent mechanism of MV-induced neurotoxicity and this was confirmed by analysing neurons with lentiviral over-expression of HMOX1. We conclude that MV exerts a neurotoxic effect in cultured neurons in a heme-independent manner.

  7. Accelerated age-related olfactory decline among type 1 Usher patients

    PubMed Central

    Ribeiro, João Carlos; Oliveiros, Bárbara; Pereira, Paulo; António, Natália; Hummel, Thomas; Paiva, António; Silva, Eduardo D.

    2016-01-01

    Usher Syndrome (USH) is a rare disease with hearing loss, retinitis pigmentosa and, sometimes, vestibular dysfunction. A phenotype heterogeneity is reported. Recent evidence indicates that USH is likely to belong to an emerging class of sensory ciliopathies. Olfaction has recently been implicated in ciliopathies, but the scarce literature about olfaction in USH show conflicting results. We aim to evaluate olfactory impairment as a possible clinical manifestation of USH. Prospective clinical study that included 65 patients with USH and 65 normal age-gender-smoking-habits pair matched subjects. A cross culturally validated version of the Sniffin’ Sticks olfaction test was used. Young patients with USH have significantly better olfactory scores than healthy controls. We observe that USH type 1 have a faster ageing olfactory decrease than what happens in healthy subjects, leading to significantly lower olfactory scores in older USH1 patients. Moreover, USH type 1 patients showed significantly higher olfactory scores than USH type 2, what can help distinguishing them. Olfaction represents an attractive tool for USH type classification and pre diagnostic screening due to the low cost and non-invasive nature of the testing. Olfactory dysfunction should be considered among the spectrum of clinical manifestations of Usher syndrome. PMID:27329700

  8. Radiolysis as a solution for accelerated ageing studies of electrolytes in Lithium-ion batteries.

    PubMed

    Ortiz, Daniel; Steinmetz, Vincent; Durand, Delphine; Legand, Solène; Dauvois, Vincent; Maître, Philippe; Le Caër, Sophie

    2015-01-01

    Diethyl carbonate and dimethyl carbonate are prototype examples of eco-friendly solvents used in lithium-ion batteries. Nevertheless, their degradation products affect both the battery performance and its safety. Therefore, it is of paramount importance to understand the reaction mechanisms involved in the ageing processes. Among those, redox processes are likely to play a critical role. Here we show that radiolysis is an ideal tool to generate the electrolytes degradation products. The major gases detected after irradiation (H2, CH4, C2H6, CO and CO2) are identified and quantified. Moreover, the chemical compounds formed in the liquid phase are characterized by different mass spectrometry techniques. Reaction mechanisms are then proposed. The detected products are consistent with those of the cycling of Li-based cells. This demonstrates that radiolysis is a versatile and very helpful tool to better understand the phenomena occurring in lithium-ion batteries. PMID:25907411

  9. Radiolysis as a solution for accelerated ageing studies of electrolytes in Lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Ortiz, Daniel; Steinmetz, Vincent; Durand, Delphine; Legand, Solène; Dauvois, Vincent; Maître, Philippe; Le Caër, Sophie

    2015-04-01

    Diethyl carbonate and dimethyl carbonate are prototype examples of eco-friendly solvents used in lithium-ion batteries. Nevertheless, their degradation products affect both the battery performance and its safety. Therefore, it is of paramount importance to understand the reaction mechanisms involved in the ageing processes. Among those, redox processes are likely to play a critical role. Here we show that radiolysis is an ideal tool to generate the electrolytes degradation products. The major gases detected after irradiation (H2, CH4, C2H6, CO and CO2) are identified and quantified. Moreover, the chemical compounds formed in the liquid phase are characterized by different mass spectrometry techniques. Reaction mechanisms are then proposed. The detected products are consistent with those of the cycling of Li-based cells. This demonstrates that radiolysis is a versatile and very helpful tool to better understand the phenomena occurring in lithium-ion batteries.

  10. Radiolysis as a solution for accelerated ageing studies of electrolytes in Lithium-ion batteries

    PubMed Central

    Ortiz, Daniel; Steinmetz, Vincent; Durand, Delphine; Legand, Solène; Dauvois, Vincent; Maître, Philippe; Le Caër, Sophie

    2015-01-01

    Diethyl carbonate and dimethyl carbonate are prototype examples of eco-friendly solvents used in lithium-ion batteries. Nevertheless, their degradation products affect both the battery performance and its safety. Therefore, it is of paramount importance to understand the reaction mechanisms involved in the ageing processes. Among those, redox processes are likely to play a critical role. Here we show that radiolysis is an ideal tool to generate the electrolytes degradation products. The major gases detected after irradiation (H2, CH4, C2H6, CO and CO2) are identified and quantified. Moreover, the chemical compounds formed in the liquid phase are characterized by different mass spectrometry techniques. Reaction mechanisms are then proposed. The detected products are consistent with those of the cycling of Li-based cells. This demonstrates that radiolysis is a versatile and very helpful tool to better understand the phenomena occurring in lithium-ion batteries. PMID:25907411

  11. Color and opacity of composites protected with surface sealants and submitted to artificial accelerated aging

    PubMed Central

    Aguilar, Fabiano Gamero; Roberti Garcia, Lucas da Fonseca; Cruvinel, Diogo Rodrigues; Sousa, Ana Beatriz Silva; de Carvalho Panzeri Pires-de-Souza, Fernanda

    2012-01-01

    Objectives: To evaluate the color similarity, stability and opacity of composites (TPH, Charisma, and Concept, shade A2) protected with surface sealants (Fortify Plus and Biscover) and cyanoacrylate (Super Bonder). Methods: Forty specimens of each composite were made and separated into 4 groups (n=10) according to the surface protection: GI - without sealant; GII - cyanoacrylate; GIII - Fortify Plus; GIV - Biscover. Color and opacity readings were taken before and after Artificial Acelerated Aging (AAA) and the values obtained for color stability were submitted to statistical analysis by 2-way ANOVA and Bonferroni’s test (P<.05). The values acquired for color similarity were submitted to 1-way ANOVA and Tukey’s test (P<.05). The specimen sufaces were compared before and after AAA using Scanning Electronic Microscopy (SEM). Results: Studied composites did not present the same values for the coordinates L*, a* and b * before AAA, indicating that there was no color similarity among them. All composites presented color alteration after AAA with clinically unacceptable values. Protected groups presented lower opacity variation after AAA, in comparison with the control goup. SEM evaluation demonstrated that AAA increased the surface irregularities in all of the studied groups. Conclusion: Surface sealants were not effective in maintaining composite color, but were able to maintain opacity. PMID:22229004

  12. Mitochondrial superoxide dismutase deficiency accelerates chronological aging in the fission yeast Schizosaccharomyces pombe.

    PubMed

    Ogata, Toshiya; Senoo, Takanori; Kawano, Shinji; Ikeda, Shogo

    2016-01-01

    A mitochondrial superoxide dismutase (SOD2) is the first line of antioxidant defense against mitochondrial superoxide. Even though the involvement of SOD2 in lifespan has been studied extensively in several organisms, characterization of the aging process has not been performed for the sod2 mutant (sod2Δ) of a prominent model Schizosaccharomyces pombe. In this study, we measured the chronological lifespan of sod2Δ cells by their ability to survive in long-term culture. SOD2 deficiency drastically decreased cell viability in the stationary phase. The mutation frequency of nuclear DNA in sod2Δ was elevated in the stationary phase, and cellular proteins and nuclear DNA were extensively degraded, concurrent with cell death. The sod2 gene in wild-type cells could be induced by an increase in endogenous oxidative stresses, after which, SOD2 activity was substantially elevated during the stationary phase. Culture in a lower glucose concentration (calorie restriction) prominently extended the sod2Δ lifespan. Therefore, S. pombe SOD2 plays a critical role in longevity through its upregulation in the non-dividing phase.

  13. Linseed oil presents different patterns of oxidation in real-time and accelerated aging assays.

    PubMed

    Douny, Caroline; Razanakolona, Rina; Ribonnet, Laurence; Milet, Jérôme; Baeten, Vincent; Rogez, Hervé; Scippo, Marie-Louise; Larondelle, Yvan

    2016-10-01

    This study aimed at verifying if the hypothesis that one day at 60°C is equivalent to one month at 20°C could be confirmed during linseed oil aging for 6months at 20°C and 6days at 60°C using the "Schaal oven stability test". Tests were conducted with linseed oil supplemented or not with myricetin or butyl-hydroxytoluene as antioxidants. Oxidation was evaluated with the peroxide and p-anisidine values, as well as the content in conjugated dienes and aldehydes. All four indicators of oxidation showed very different kinetic behaviors at 20 and 60°C. The hypothesis is thus not verified for linseed oil, supplemented or not with antioxidant. In the control oil, the conjugated dienes and the peroxide value observed were respectively of 41.8±0.8 Absorbance Unit (AU)/g oil and 254.3±5.8meq.O2/kg oil after 6months at 20°C. These values were of 18.2±1.3AU/g oil and 65.2±20.3meq.O2/kg after 6days at 60°C.

  14. Effect of weaning age on hair sheep lamb and ewe production traits in an accelerated lambing system in the tropics.

    PubMed

    Godfrey, R W; Weis, A J

    2016-03-01

    This study was designed to evaluate the impact of weaning age on lamb and ewe productivity in an accelerated lambing system. St. Croix White (STX) and Dorper × St. Croix White (DRPX) lambs were assigned at birth based on breed, gender, and litter size to be weaned at 63 (Early-1; 106 lambs and 68 ewes) or 90 d of age (Late-1; 99 lambs and 60 ewes) in Exp.1 or at 63 (Early-2; 77 lambs and 57 ewes) or 120 d of age (Late-2; 75 lambs and 56 ewes) in Exp. 2. After weaning, lambs were weighed weekly and fed a concentrate ration (2% BW·lamb·d) while grazing guinea grass pastures. In Exp. 1, weaning weight was greater ( < 0.0001) for Late-1 lambs than for Early-1 lambs (14.6 ± 0.3 vs. 11.0 ± 0.3 kg, respectively) and greater ( < 0.008) for DRPX lambs than for STX lambs (13.9 ± 0.4 vs. 11.5 ± 0.4 kg, respectively). Litter weaning weight was greater ( < 0.004) for Late-1 ewes than for Early-1 ewes (20.9 ± 0.8 vs. 17.4 ± 0.8 kg, respectively). Ewe efficiency ([ewe BW at weaning/litter weaning weight] × 100) was greater ( < 0.004) for Late-1 ewes than for Early-1 ewes (50.7 ± 1.9 vs. 42.3 ± 1.8%, respectively). Lamb weight gain between 63 and 90 d of age was lower ( < 0.03) for Early-1 lambs than for Late-1 lambs (2.7 ± 0.2 vs. 3.6 ± 0.3 kg, respectively). In Exp. 2, weaning weight was greater ( < 0.0001) for Late-2 lambs than for Early-2 lambs (18.7 ± 0.4 vs. 11.8 ± 0.4 kg, respectively) and greater ( < 0.008) for DRPX lambs than for STX lambs (16.9 ± 0.5 vs. 13.3 ± 0.5 kg, respectively). Litter weaning weight was greater ( < 0.0001) in Late-2 ewes than in Early-2 ewes (27.2 ± 1.0 vs. 17.5 ± 0.9 kg, respectively). Ewe efficiency was greater ( < 0.0001) for Late-2 ewes than for Early-2 ewes (68.1 ± 2.2 vs. 41.9 ± 2.0%, respectively). Lamb weight gain between 63 and 120 d of age was not different ( > 0.06) between Early-2 and Late-2 lambs (5.1 ± 0.2 vs. 5.6 ± 0.3 kg, respectively). In Exp. 1 and 2, ewe BW at breeding and lambing and weaning and lambing

  15. Cigarette Smoking Accelerated Brain Aging and Induced Pre-Alzheimer-Like Neuropathology in Rats

    PubMed Central

    Ho, Yuen-Shan; Yang, Xifei; Yeung, Sze-Chun; Chiu, Kin; Lau, Chi-Fai; Tsang, Andrea Wing-Ting; Mak, Judith Choi-Wo; Chang, Raymond Chuen-Chung

    2012-01-01

    Cigarette smoking has been proposed as a major risk factor for aging-related pathological changes and Alzheimer's disease (AD). To date, little is known for how smoking can predispose our brains to dementia or cognitive impairment. This study aimed to investigate the cigarette smoke-induced pathological changes in brains. Male Sprague-Dawley (SD) rats were exposed to either sham air or 4% cigarette smoke 1 hour per day for 8 weeks in a ventilated smoking chamber to mimic the situation of chronic passive smoking. We found that the levels of oxidative stress were significantly increased in the hippocampus of the smoking group. Smoking also affected the synapse through reducing the expression of pre-synaptic proteins including synaptophysin and synapsin-1, while there were no changes in the expression of postsynaptic protein PSD95. Decreased levels of acetylated-tubulin and increased levels of phosphorylated-tau at 231, 205 and 404 epitopes were also observed in the hippocampus of the smoking rats. These results suggested that axonal transport machinery might be impaired, and the stability of cytoskeleton might be affected by smoking. Moreover, smoking affected amyloid precursor protein (APP) processing by increasing the production of sAPPβ and accumulation of β–amyloid peptide in the CA3 and dentate gyrus region. In summary, our data suggested that chronic cigarette smoking could induce synaptic changes and other neuropathological alterations. These changes might serve as evidence of early phases of neurodegeneration and may explain why smoking can predispose brains to AD and dementia. PMID:22606286

  16. Age effect on fatigue-induced limb acceleration as a consequence of high-level sustained submaximal contraction.

    PubMed

    Huang, Chien-Ting; Huang, Chien-Chun; Young, Ming-Shing; Hwang, Ing-Shiou

    2007-08-01

    In reference to electromyographic measurement, the study was conducted to reassess differences in the behavior of fatigue-related neuromuscular function between young and elderly humans with limb acceleration (LA). Fourteen young and fourteen elderly subjects performed sustained index abduction at 75% of their maximal voluntary contractions (MVC) until task failure. Measures of neuromuscular function, including temporal/spectral features of muscle activity of the first dorsal interosseous (FDI) and LA of the index and hand, were monitored. The results showed a manifest fatigue-induced increase in LA of the index in the elderly group, but not in the young group. In contrast, only the young group developed a significant increase in amplitude of the electromyography (EMG) until task failure. Spectral analyses of LA in the index reflected marked age-dependent reorganization following muscle fatigue, with a greater reduction of relative spectral amplitude of LA in the range of 20-40 Hz, but a lesser reduction in coherence between EMG and LA in the elderly group. In line with fatigue-associated restructuring of LA, the mechanical coupling of the metacarpophalangeal joint was more severely undermined in the elderly group than in the young group. The present study manifested an age-related difference in the relative contributions of neural versus mechanical factors to muscle fatigue. Subsequent to a high-level sustained submaximal isometric contraction, a predominant mechanical failure of the musculotendon complex in the elderly was featured with LA, whereas EMG measurement characterized prevailing impairment of neuromuscular propagation in the young.

  17. Prognostics of Power Mosfets Under Thermal Stress Accelerated Aging Using Data-Driven and Model-Based Methodologies

    NASA Technical Reports Server (NTRS)

    Celaya, Jose; Saxena, Abhinav; Saha, Sankalita; Goebel, Kai F.

    2011-01-01

    An approach for predicting remaining useful life of power MOSFETs (metal oxide field effect transistor) devices has been developed. Power MOSFETs are semiconductor switching devices that are instrumental in electronics equipment such as those used in operation and control of modern aircraft and spacecraft. The MOSFETs examined here were aged under thermal overstress in a controlled experiment and continuous performance degradation data were collected from the accelerated aging experiment. Dieattach degradation was determined to be the primary failure mode. The collected run-to-failure data were analyzed and it was revealed that ON-state resistance increased as die-attach degraded under high thermal stresses. Results from finite element simulation analysis support the observations from the experimental data. Data-driven and model based prognostics algorithms were investigated where ON-state resistance was used as the primary precursor of failure feature. A Gaussian process regression algorithm was explored as an example for a data-driven technique and an extended Kalman filter and a particle filter were used as examples for model-based techniques. Both methods were able to provide valid results. Prognostic performance metrics were employed to evaluate and compare the algorithms.

  18. Models of Metal-poor Stars with Gravitational Settling and Radiative Accelerations. II. The Age of the Oldest Stars

    NASA Astrophysics Data System (ADS)

    VandenBerg, Don A.; Richard, O.; Michaud, G.; Richer, J.

    2002-05-01

    Isochrones for ages between 12 and 18 Gyr have been derived from the evolutionary tracks presented in Paper I (Richard et al.) for masses from 0.5 to 1.0 Msolar and initial chemical abundances corresponding to (1) Y=0.2352, Z=1.69×10-4 ([Fe/H]=-2.31,[α/Fe]=0.3) and (2) Y=0.2370, Z=1.69×10-3 ([Fe/H=-1.31,[α/Fe]=0.3). These are the first models for Population II stars in which both gravitational settling and radiative accelerations have been taken into account. Allowance for these diffusive processes leads to a 10%-12% reduction in age at a given turnoff luminosity. However, in order for the diffusive models to satisfy the constraints from Li and Fe abundance data (see Paper I) and to reproduce the observed morphologies of globular cluster (GC) color-magnitude diagrams (CMDs) in a straightforward way, extra mixing just below the boundary of the convective envelope seems to be necessary. Indeed, when additional turbulent mixing is invoked, the resultant models are able to satisfy all of these constraints, as well as those provided by the CMDs of local subdwarfs, rather well. Moreover, they imply an age near 13.5 Gyr for M92, which is one of the most metal-deficient (and presumably one of the oldest) of the Galaxy's GCs, if the field subgiant HD 140283 is used to derive the cluster distance. Comparisons of field subdwarfs and subgiants with a recently published fiducial for M5 suggests that the cluster has [Fe/H]<~-1.4, in conflict with some estimates based on high-resolution spectroscopy, if the metallicities of the field stars are to be trusted. In addition, an age of ~11.5 Gyr is found for M5, irrespective of whether diffusive or nondiffusive isochrones are employed in the analysis. The implications of our results for the extragalactic distance scale and for the Hubble constant are briefly discussed in the context of the presently favored ΩM~0.35, ΩΛ~0.65 cosmological model.

  19. Dynamic mechanical and molecular weight measurements on polymer bonded explosives from thermally accelerated aging tests. I. Fluoropolymer binders

    SciTech Connect

    Hoffman, D.M.; Caley, L.E.

    1981-01-01

    The dynamic mechanical properties and molecular weight distribution of two polymer bonded explosives, LX-10-1 and PBX-9502, maintained at 23, 60, and 74/sup 0/C for 3 years were studied. LX-10-1 is 94.5% 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane explosive bonded together with 5.5% Viton A fluoropolymer. PBX-9502 is 95% triaminotrinitrobenzene explosive bonded with 5% Kel-F-800 fluoropolymer. There are two mechanical relaxations in the LX-10-1 in the military temperature range. The relaxation at -10/sup 0/C is associated with the glass transition temperature of the Viton A binder. A second weak relaxation occurs at about 30/sup 0/C in all LX-10-1 samples tested. This relaxation is probably associated with small amounts of crystallinity in the binder although this has not been demonstrated. There is a slight increase in modulus of the LX-10-1 with accelerated aging temperature. Changes in the dynamic mechanical properties of PBX-9502 are ascribed to crystallization of the chlorotrifluoroethylene component of the Kel-F-800 binder. The molecular weight of the Viton A binder decreased slight with increasing aging temperature. Using the kinetics of random scission the activation energy for polymer degradation in the presence of the explosive was 1.19 kcal/mole. The Arrhenius preexponential term and activation energy predict an expected use-life in excess of 60 years for LX-10-1. The Kel-F-800 in PBX-9502 is also extremely stable.

  20. Endocrine and fluid metabolism in males and females of different ages after bedrest, acceleration and lower body negative pressure

    NASA Technical Reports Server (NTRS)

    Leach, C. S.; Vernikos-Danellis, J.; Krauhs, J. M.; Sandler, H.

    1985-01-01

    Space shuttle flight simulations were conducted to determine the effects of weightlessness, lower body negative pressure (LBNP), and acceleration of fluid and electrolyte excretion and the hormones that control it. Measurements were made on male and female subjects of different ages before and after bedrest. After admission to a controlled environment, groups of 6 to 14 subjects in the age ranges 25 to 35, 35 to 45, 45 to 55 to 65 years were exposed to +3 G sub z for 15 minutes (G1) and to LBNP (LBNP1) on different days. On 3 days during this prebedrest period, no tests were conducted. Six days of bedrest followed, and the G sub z (G2) and LBNP (LBNP2) tests were run again. Hormones, electrolytes, and other parameters were measured in 24-hour urine pools throughout the experiment. During bedrest, cortisol and aldosterone excretion increased. Urine volume decreased, and specific gravity and osmolality increased. Urinary electrolytes were statistically unchanged from levels during the non-stress control period. During G2, cortisol increased significantly over its control and bedrest levels. Urine volume, sodium, and chloride were significantly lower; specific gravity and osmolality were higher during the control period or bedrest. The retention of fluids and electrolytes after +G sub z may at least partially explain decreased urine volume and increased osmolality observed during bedrest in this study. There were some who indicated that space flight would not affect the fluid and electrolyte metabolism of females or older males any more severely than it has affected that of male astronauts.

  1. High-fat diet intake accelerates aging, increases expression of Hsd11b1, and promotes lipid accumulation in liver of SAMP10 mouse.

    PubMed

    Honma, Taro; Shinohara, Nahoko; Ito, Junya; Kijima, Ryo; Sugawara, Soko; Arai, Tatsuya; Tsuduki, Tsuyoshi; Ikeda, Ikuo

    2012-04-01

    An understanding of the mechanisms of aging is important for prevention of age-related diseases. In this study, we examined age-dependent changes in lipid metabolism in the senescence-accelerated mouse (SAM)P10 fed a high-fat diet to investigate the effects of high-fat intake and aging. Tissue weights and biological parameters in plasma and liver were measured at 6 and 12 months old in SAMP10 mice fed a high-fat diet. These mice showed marked increases in liver triacylglycerol and plasma insulin levels with intake of a high-fat diet intake and aging. Lipid accumulation in hepatocytes and morphological aberrations and hypertrophy in pancreatic islets were also promoted by a high-fat diet and aging. To investigate the underlying mechanisms, the activities and mRNA levels for enzymes associated with lipid metabolism in liver were measured. The results indicated that the lipid metabolic system was activated by a high-fat diet and aging. Liver mRNA level for hydroxysteroid 11-beta dehydrogenase 1 (Hsd11b1), which exhibit age-dependent increases and promote insulin secretion, was also markedly increased. These results suggest that a high-fat diet accelerated aging in the liver of SAMP10 mice by increasing liver mRNA level for Hsd11b1, increasing insulin secretion, and promoting lipid accumulation in the liver.

  2. Influence of Different Types of Resin Luting Agents on Color Stability of Ceramic Laminate Veneers Subjected to Accelerated Artificial Aging.

    PubMed

    Silami, Francisca Daniele Jardilino; Tonani, Rafaella; Alandia-Román, Carla Cecilia; Pires-de-Souza, Fernanda de Carvalho Panzeri

    2016-01-01

    The aim of this study was to evaluate the influence of accelerated aging (AAA) on the color stability of resin cements for bonding ceramic laminate veneers of different thicknesses. The occlusal surfaces of 80 healthy human molars were flattened. Ceramic laminate veneers (IPS e-max Ceram) of two thicknesses (0.5 and 1.0 mm) were bonded with three types of luting agents: light-cured, conventional dual and self-adhesive dual cement. Teeth without restorations and cement samples (0.5 mm) were used as control. After initial color evaluations, the samples were subjected to AAA for 580 h. After this, new color readouts were made, and the color stability (ΔE) and luminosity (ΔL) data were analyzed. The greatest color changes (p<0.05) occurred when 0.5 mm veneers were fixed with light-cured cement and the lowest when 1.0 mm veneers were fixed with conventional dual cement. There was no influence of the restoration thickness when the self-adhesive dual cement was used. When veneers were compared with the control groups, it was verified that the cement samples presented the greatest alterations (p<0.05) in comparison with both substrates and restored teeth. Therefore, it was concluded that the thickness of the restoration influences color and luminosity changes for conventional dual and light-cured cements. The changes in self-adhesive cement do not depend on restoration thickness.

  3. Folate Acts in E. coli to Accelerate C. elegans Aging Independently of Bacterial Biosynthesis

    PubMed Central

    Virk, Bhupinder; Jia, Jie; Maynard, Claire A.; Raimundo, Adelaide; Lefebvre, Jolien; Richards, Shane A.; Chetina, Natalia; Liang, Yen; Helliwell, Noel; Cipinska, Marta; Weinkove, David

    2016-01-01

    Summary Folates are cofactors for biosynthetic enzymes in all eukaryotic and prokaryotic cells. Animals cannot synthesize folate and must acquire it from their diet or microbiota. Previously, we showed that inhibiting E. coli folate synthesis increases C. elegans lifespan. Here, we show that restriction or supplementation of C. elegans folate does not influence lifespan. Thus, folate is required in E. coli to shorten worm lifespan. Bacterial proliferation in the intestine has been proposed as a mechanism for the life-shortening influence of E. coli. However, we found no correlation between C. elegans survival and bacterial growth in a screen of 1,000+ E. coli deletion mutants. Nine mutants increased worm lifespan robustly, suggesting specific gene regulation is required for the life-shortening activity of E. coli. Disrupting the biosynthetic folate cycle did not increase lifespan. Thus, folate acts through a growth-independent route in E. coli to accelerate animal aging. PMID:26876180

  4. Influence of Different Types of Resin Luting Agents on Color Stability of Ceramic Laminate Veneers Subjected to Accelerated Artificial Aging.

    PubMed

    Silami, Francisca Daniele Jardilino; Tonani, Rafaella; Alandia-Román, Carla Cecilia; Pires-de-Souza, Fernanda de Carvalho Panzeri

    2016-01-01

    The aim of this study was to evaluate the influence of accelerated aging (AAA) on the color stability of resin cements for bonding ceramic laminate veneers of different thicknesses. The occlusal surfaces of 80 healthy human molars were flattened. Ceramic laminate veneers (IPS e-max Ceram) of two thicknesses (0.5 and 1.0 mm) were bonded with three types of luting agents: light-cured, conventional dual and self-adhesive dual cement. Teeth without restorations and cement samples (0.5 mm) were used as control. After initial color evaluations, the samples were subjected to AAA for 580 h. After this, new color readouts were made, and the color stability (ΔE) and luminosity (ΔL) data were analyzed. The greatest color changes (p<0.05) occurred when 0.5 mm veneers were fixed with light-cured cement and the lowest when 1.0 mm veneers were fixed with conventional dual cement. There was no influence of the restoration thickness when the self-adhesive dual cement was used. When veneers were compared with the control groups, it was verified that the cement samples presented the greatest alterations (p<0.05) in comparison with both substrates and restored teeth. Therefore, it was concluded that the thickness of the restoration influences color and luminosity changes for conventional dual and light-cured cements. The changes in self-adhesive cement do not depend on restoration thickness. PMID:27007354

  5. Acceleration of aged-landfill stabilization by combining partial nitrification and leachate recirculation: a field-scale study.

    PubMed

    Chung, Jinwook; Kim, Seungjin; Baek, Seungcheon; Lee, Nam-Hoon; Park, Seongjun; Lee, Junghun; Lee, Heechang; Bae, Wookeun

    2015-03-21

    Leachate recirculation for rapid landfill stabilization can result in the accumulation of high-strength ammonium. An on-site sequencing batch reactor (SBR) was therefore, applied to oxidize the ammonium to nitrite, which was then recirculated to the landfill for denitrification to nitrogen gas. At relatively higher ammonium levels, nitrite accumulated well in the SBR; the nitrite was denitrified stably in the landfill, despite an insufficient biodegradable carbon source in the leachate. As the leachate was recirculated, the methane and carbon dioxide contents produced from the landfill fluctuated, implying that the organic acids and hydrogen produced in the acid production phase acted as the carbon source for denitrification in the landfill. Leachate recirculation combined with ex-situ partial nitrification of the leachate may enhance the biodegradation process by: (a) removing the nitrogen that is contained with the leachate, and (b) accelerating landfill stabilization, because the biodegradation efficiency of landfill waste is increased by supplying sufficient moisture and its byproducts are used as the carbon source for denitrification. In addition, partial nitrification using an SBR has advantages for complete denitrification in the landfill, since the available carbon source is in short supply in aged landfills.

  6. Folate Acts in E. coli to Accelerate C. elegans Aging Independently of Bacterial Biosynthesis.

    PubMed

    Virk, Bhupinder; Jia, Jie; Maynard, Claire A; Raimundo, Adelaide; Lefebvre, Jolien; Richards, Shane A; Chetina, Natalia; Liang, Yen; Helliwell, Noel; Cipinska, Marta; Weinkove, David

    2016-02-23

    Folates are cofactors for biosynthetic enzymes in all eukaryotic and prokaryotic cells. Animals cannot synthesize folate and must acquire it from their diet or microbiota. Previously, we showed that inhibiting E. coli folate synthesis increases C. elegans lifespan. Here, we show that restriction or supplementation of C. elegans folate does not influence lifespan. Thus, folate is required in E. coli to shorten worm lifespan. Bacterial proliferation in the intestine has been proposed as a mechanism for the life-shortening influence of E. coli. However, we found no correlation between C. elegans survival and bacterial growth in a screen of 1,000+ E. coli deletion mutants. Nine mutants increased worm lifespan robustly, suggesting specific gene regulation is required for the life-shortening activity of E. coli. Disrupting the biosynthetic folate cycle did not increase lifespan. Thus, folate acts through a growth-independent route in E. coli to accelerate animal aging.

  7. The Macular Degeneration and Aging Study: Design and Research Protocol of a Randomized Trial for a Psychosocial Intervention with Macular Degeneration Patients

    PubMed Central

    Sörensen, Silvia; White, Katherine; Mak, Wingyun; Zanibbi, Katherine; Tang, Wan; O’Hearn, Amanda; Hegel, Mark T.

    2015-01-01

    Age-related Macular Degeneration (AMD) is the leading cause of irreversible and predictable blindness among older adults and creates serious physical and mental health consequences for this population. Visual impairment is associated with negative future outlook and depression and has serious consequences for older adults’ quality of life and, by way of depression, on long-term survival. Psychosocial interventions have the potential to alleviate and prevent depression symptoms among older AMD patients. We describe the protocol of the Macular Degeneration and Aging Study, a randomized clinical trial of a psychosocial Preventive Problem-Solving Intervention. The intervention is aimed at enhancing well-being and future planning among older adults with macular degeneration by increasing preparation for future care. Adequate randomization and therapeutic fidelity were achieved. Current retention rates were acceptable, given the vulnerability of the population. Acceptability (adherence and satisfaction) is high. Given the high public health significance and impact on quality of life among older adults with vision loss, this protocol contributes a valid test of a promising intervention for maintaining mental and physical health in this population. PMID:25812482

  8. Clinico-biological features of 5202 patients with acute lymphoblastic leukemia enrolled in the Italian AIEOP and GIMEMA protocols and stratified in age cohorts

    PubMed Central

    Chiaretti, Sabina; Vitale, Antonella; Cazzaniga, Gianni; Orlando, Sonia Maria; Silvestri, Daniela; Fazi, Paola; Valsecchi, Maria Grazia; Elia, Loredana; Testi, Anna Maria; Mancini, Francesca; Conter, Valentino; te Kronnie, Geertruy; Ferrara, Felicetto; Di Raimondo, Francesco; Tedeschi, Alessandra; Fioritoni, Giuseppe; Fabbiano, Francesco; Meloni, Giovanna; Specchia, Giorgina; Pizzolo, Giovanni; Mandelli, Franco; Guarini, Anna; Basso, Giuseppe; Biondi, Andrea; Foà, Robin

    2013-01-01

    The outcome of children and adults with acute lymphoblastic leukemia is markedly different. Since there is limited information on the distribution of clinico-biological variables in different age cohorts, we analyzed 5202 patients with acute lymphoblastic leukemia enrolled in the Italian multicenter AIEOP and GIMEMA protocols and stratified them in nine age cohorts. The highest prevalence of acute lymphoblastic leukemia was observed in children, although a second peak was recorded from the 4th decade onwards. Interestingly, the lowest incidence was found in females between 14–40 years. Immunophenotypic characterization showed a B-lineage in 85.8% of patients: a pro-B stage, associated with MLL/AF4 positivity, was more frequent in patients between 10–50 years. T-lineage leukemia (14.2%) was rare among small children and increased in patients aged 10–40 years. The prevalence of the BCR/ABL1 rearrangement increased progressively with age starting from the cohort of patients 10–14 years old and was present in 52.7% of cases in the 6th decade. Similarly, the MLL/AF4 rearrangement constantly increased up to the 5th decade, while the ETV6/RUNX1 rearrangement disappeared from the age of 30 onwards. This study shows that acute lymphoblastic leukemia in adolescents and young adults is characterized by a male prevalence, higher percentage of T-lineage cases, an increase of poor prognostic molecular markers with aging compared to cases in children, and conclusively quantified the progressive increase of BCR/ABL+ cases with age, which are potentially manageable by targeted therapies. PMID:23716539

  9. Does progressive resistance and balance exercise reduce falls in residential aged care? Randomized controlled trial protocol for the SUNBEAM program

    PubMed Central

    Hewitt, Jennifer; Refshauge, Kathryn M; Goodall, Stephen; Henwood, Timothy; Clemson, Lindy

    2014-01-01

    Introduction Falls are common among older adults. It is reported that approximately 60% of residents of aged care facilities fall each year. This is a major cause of morbidity and mortality, and a significant burden for health care providers and the health system. Among community dwelling older adults, exercise appears to be an effective countermeasure, but data are limited and inconsistent among studies in residents of aged care communities. This trial has been designed to evaluate whether the SUNBEAM program (Strength and Balance Exercise in Aged Care) reduces falls in residents of aged care facilities. Research question Is the program more effective and cost-effective than usual care for the prevention of falls? Design Single-blinded, two group, cluster randomized trial. Participants and setting 300 residents, living in 20 aged care facilities. Intervention Progressive resistance and balance training under the guidance of a physiotherapist for 6 months, then facility-guided maintenance training for 6 months. Control Usual care. Measurements Number of falls, number of fallers, quality of life, mobility, balance, fear of falling, cognitive well-being, resource use, and cost-effectiveness. Measurements will be taken at baseline, 6 months, and 12 months. Analysis The number of falls will be analyzed using a Poisson mixed model. A logistic mixed model will be used to analyze the number of residents who fall during the study period. Intention-to-treat analysis will be used. Discussion This study addresses a significant shortcoming in aged care research, and has potential to impact upon a substantial health care problem. Outcomes will be used to inform care providers, and guide health care policies. PMID:24591821

  10. Prediction of Preadolescent Overweight and Poor Cardiometabolic Outcome in Children up to 6 Years of Age: Research Protocol

    PubMed Central

    Wijga, Alet; Vergouwe, Yvonne; Heijmans, Martijn W; Jaddoe, Vincent WV; Twisk, Jos WR; Raat, Hein

    2016-01-01

    Background Dynamic risk estimations may enable targeting primary prevention of overweight and overweight-related adverse cardiometabolic outcome in later life, potentially serving as a valuable addition to universal primary prevention. This approach seems particularly promising in young children, as body mass index (BMI) changes at a young age are highly predictive of these outcomes, and parental lifestyle interventions at a young age are associated with improved long-term outcome. Objective This paper describes the design of our study, which aims to develop digitized tools that can be implemented in the Dutch Child Health Care (CHC) system or by pediatricians for children up to 6 years of age. These tools will enable (1) dynamically predicting the development of overweight, hypertension or prehypertension, low high-density lipoprotein cholesterol (HDL-C) values, and high total cholesterol to HDL-C ratio by early adolescence and (2) identifying children who are likely to have poor cardiometabolic outcome by the age of 5-6 years and by the age of 10 years. Methods Data will be obtained from the Generation R (n=7893) and Prevention and Incidence of Asthma and Mite Allergy (PIAMA; n=3963) cohorts, two Dutch prenatally recruited cohorts. We will select candidate predictors that can be assessed during the first visit and/or during subsequent visits to the CHC center or pediatrician, including sex; parental age, education level, and BMI; smoking exposure; ethnicity; birth weight; gestational age; breastfeeding versus formula feeding; and growth data through the age of 6 years. We will design dynamic prediction models that can be updated with new information obtained during subsequent CHC visits, allowing each measurement to be added to the model. Performance of the model will be assessed in terms of discrimination and calibration. Finally, the model will be validated both internally and externally using the combined cohort data and then converted into a computer

  11. In vitro analysis of different properties of acrylic resins for ocular prosthesis submitted to accelerated aging with or without photopolymerized glaze.

    PubMed

    Santos, Daniela Micheline Dos; Nagay, Bruna Egumi; da Silva, Emily Vivianne Freitas; Bonatto, Liliane da Rocha; Sonego, Mariana Vilela; Moreno, Amália; Rangel, Elidiane Cipriano; da Cruz, Nilson Cristino; Goiato, Marcelo Coelho

    2016-12-01

    The effect of a photopolymerized glaze on different properties of acrylic resin (AR) for ocular prostheses submitted to accelerated aging was investigated. Forty discs were divided into 4 groups: N1 AR without glaze (G1); colorless AR without glaze (G2); N1 AR with glaze (G3); and colorless AR with glaze (G4). All samples were polished with sandpaper (240, 600 and 800-grit). In G1 and G2, a 1200-grit sandpaper was also used. In G3 and G4, samples were coated with MegaSeal glaze. Property analysis of color stability, microhardness, roughness, and surface energy, and assays of atomic force microscopy, scanning electron microscopy, and energy-dispersive spectroscopy were performed before and after the accelerated aging (1008h). Data were submitted to the ANOVA and Tukey Test (p<0.05). Groups with glaze exhibited statistically higher color change and roughness after aging. The surface microhardness significantly decreased in groups with glaze and increased in groups without glaze. The surface energy increased after the aging, independent of the polishing procedure. All groups showed an increase of surface irregularities. Photopolymerized glaze is an inadequate surface treatment for AR for ocular prostheses and it affected the color stability, roughness, and microhardness. The accelerated aging interfered negatively with the properties of resins. PMID:27612795

  12. In vitro analysis of different properties of acrylic resins for ocular prosthesis submitted to accelerated aging with or without photopolymerized glaze.

    PubMed

    Santos, Daniela Micheline Dos; Nagay, Bruna Egumi; da Silva, Emily Vivianne Freitas; Bonatto, Liliane da Rocha; Sonego, Mariana Vilela; Moreno, Amália; Rangel, Elidiane Cipriano; da Cruz, Nilson Cristino; Goiato, Marcelo Coelho

    2016-12-01

    The effect of a photopolymerized glaze on different properties of acrylic resin (AR) for ocular prostheses submitted to accelerated aging was investigated. Forty discs were divided into 4 groups: N1 AR without glaze (G1); colorless AR without glaze (G2); N1 AR with glaze (G3); and colorless AR with glaze (G4). All samples were polished with sandpaper (240, 600 and 800-grit). In G1 and G2, a 1200-grit sandpaper was also used. In G3 and G4, samples were coated with MegaSeal glaze. Property analysis of color stability, microhardness, roughness, and surface energy, and assays of atomic force microscopy, scanning electron microscopy, and energy-dispersive spectroscopy were performed before and after the accelerated aging (1008h). Data were submitted to the ANOVA and Tukey Test (p<0.05). Groups with glaze exhibited statistically higher color change and roughness after aging. The surface microhardness significantly decreased in groups with glaze and increased in groups without glaze. The surface energy increased after the aging, independent of the polishing procedure. All groups showed an increase of surface irregularities. Photopolymerized glaze is an inadequate surface treatment for AR for ocular prostheses and it affected the color stability, roughness, and microhardness. The accelerated aging interfered negatively with the properties of resins.

  13. Differences in gait velocity and trunk acceleration during semicircular turning gait with and without bag in females of very advanced age.

    PubMed

    Shin, Sun-Shil; Yoo, Won-Gyu

    2016-08-01

    [Purpose] Gait velocity and trunk acceleration during semicircular turning gait with and without carrying a hand-held bag were compared in females of very advanced age. [Subjects and Methods] Ten female volunteers of very advanced age who could walk independently were recruited for this study. Gait velocity and trunk acceleration were measured using an accelerometer during semicircular turning gait with and without carrying a hand-held bag. [Results] Gait velocity during semicircular turning gait was greater with the bag than without the bag. [Conclusions] Trunk stability during semicircular turning gait was higher when the subjects carried a bag. Additional arm load could be considered during gait training in females of very advanced age. PMID:27630425

  14. Differences in gait velocity and trunk acceleration during semicircular turning gait with and without bag in females of very advanced age

    PubMed Central

    Shin, Sun-Shil; Yoo, Won-Gyu

    2016-01-01

    [Purpose] Gait velocity and trunk acceleration during semicircular turning gait with and without carrying a hand-held bag were compared in females of very advanced age. [Subjects and Methods] Ten female volunteers of very advanced age who could walk independently were recruited for this study. Gait velocity and trunk acceleration were measured using an accelerometer during semicircular turning gait with and without carrying a hand-held bag. [Results] Gait velocity during semicircular turning gait was greater with the bag than without the bag. [Conclusions] Trunk stability during semicircular turning gait was higher when the subjects carried a bag. Additional arm load could be considered during gait training in females of very advanced age. PMID:27630425

  15. Differences in gait velocity and trunk acceleration during semicircular turning gait with and without bag in females of very advanced age

    PubMed Central

    Shin, Sun-Shil; Yoo, Won-Gyu

    2016-01-01

    [Purpose] Gait velocity and trunk acceleration during semicircular turning gait with and without carrying a hand-held bag were compared in females of very advanced age. [Subjects and Methods] Ten female volunteers of very advanced age who could walk independently were recruited for this study. Gait velocity and trunk acceleration were measured using an accelerometer during semicircular turning gait with and without carrying a hand-held bag. [Results] Gait velocity during semicircular turning gait was greater with the bag than without the bag. [Conclusions] Trunk stability during semicircular turning gait was higher when the subjects carried a bag. Additional arm load could be considered during gait training in females of very advanced age.

  16. Lifetime Occupational Physical Activity and Musculoskeletal Aging in Middle-Aged Men and Women in Denmark: Retrospective Cohort Study Protocol and Methods

    PubMed Central

    Mortensen, Ole Steen; Reventlow, Susanne; Skov, Peder Georg; Andersen, Johan Hviid; Rubak, Tine Steen; Hansen, Åse Marie; Andersen, Lars L; Lund, Rikke; Osler, Merete; Christensen, Ulla; Avlund, Kirsten

    2012-01-01

    Background Physical function is essential for performing most aspects of daily life and musculoskeletal aging leads to a decline in physical function. The onset and rate of this process vary and are influenced by environmental, genetic, and hormonal factors. Although everyone eventually experiences musculoskeletal aging, it is beneficial to study the factors that influence the aging process in order to prevent disability. The role of occupational physical activity in the musculoskeletal aging process is unclear. In the past, hard physical work was thought to strengthen the worker, but current studies in this field fail to find a training effect in jobs with a high level of occupational physical activity. Objective The aim of this study is to examine the influence of lifetime occupational physical activity on physical function in midlife. The study follows the “occupational life-course perspective,” emphasizing the importance of occupational exposures accumulated throughout life on the musculoskeletal aging process taking socioeconomic and lifestyle factors into consideration. Methods This study is a retrospective cohort study including a cross-sectional measurement of physical function in 5000 middle-aged Danes. Data was obtained from the Copenhagen Aging and Midlife Biobank (CAMB) which is based on three existing Danish cohorts. Using questionnaire information about the five longest-held occupations, the job history was coded from the Danish version of the International Standard Classification of Occupations (D-ISCO 88) and a job exposure matrix containing information about occupational physical activity in Danish jobs was applied to the dataset. The primary outcomes are three tests of physical function: handgrip strength, balance, and chair rise. In the analyses, we will compare physical function in midlife according to accumulated exposure to high levels of occupational physical activity. Conclusions We have a unique opportunity to study the influence of

  17. Effect of artificial accelerated aging on the optical properties and monomeric conversion of composites used after expiration date.

    PubMed

    Garcia, Lucas da Fonseca Roberti; Mundim, Fabricio Mariano; Pires-de-Souza, Fernanda de Carvalho Panzeri; Puppin Rontani, Regina Maria; Consani, Simonides

    2013-01-01

    This study sought to evaluate how artificial accelerated aging (AAA) affected color stability (ΔE), opacity (ΔOP), and degree of conversion (DOC) for 3 composite materials (Tetric Ceram, Tetric Ceram HB, and Tetric Flow) used both 180 days before and 180 days after their expiration dates. To evaluate the materials' optical properties, 10 specimens of each composite-5 prior to expiration and 5 after the materials' expiration date-were made in a teflon matrix. After polishing, the specimens were submitted to initial color and opacity readings and submitted to AAA for 384 hours; at that point, new readings were taken to determine ΔE and ΔOP. To evaluate monomeric conversion evaluation, 6 specimens from each composite and expiration date-3 prior to AAA and 3 after-were submitted to DOC analysis. Results of the 2-way ANOVA and Bonferroni's tests (P < 0.05) demonstrated that all composites had ΔE values above the clinically acceptable level (ΔE ≥ 3.3). When expiration dates were compared, only Tetric Flow showed a statistically significant difference (P < 0.05). Regardless of the expiration date, ΔOP values for all composites increased after AAA, but not significantly (P > 0.05). The expired Tetric Flow had the highest DOC values (71.42% ± 4.21) before AAA, significantly different than that of the other composites (P > 0.05). It was concluded that both expiration date and AAA affected the properties of the composites tested.

  18. Effect of artificial accelerated aging on the optical properties and monomeric conversion of composites used after expiration date.

    PubMed

    Garcia, Lucas da Fonseca Roberti; Mundim, Fabricio Mariano; Pires-de-Souza, Fernanda de Carvalho Panzeri; Puppin Rontani, Regina Maria; Consani, Simonides

    2013-01-01

    This study sought to evaluate how artificial accelerated aging (AAA) affected color stability (ΔE), opacity (ΔOP), and degree of conversion (DOC) for 3 composite materials (Tetric Ceram, Tetric Ceram HB, and Tetric Flow) used both 180 days before and 180 days after their expiration dates. To evaluate the materials' optical properties, 10 specimens of each composite-5 prior to expiration and 5 after the materials' expiration date-were made in a teflon matrix. After polishing, the specimens were submitted to initial color and opacity readings and submitted to AAA for 384 hours; at that point, new readings were taken to determine ΔE and ΔOP. To evaluate monomeric conversion evaluation, 6 specimens from each composite and expiration date-3 prior to AAA and 3 after-were submitted to DOC analysis. Results of the 2-way ANOVA and Bonferroni's tests (P < 0.05) demonstrated that all composites had ΔE values above the clinically acceptable level (ΔE ≥ 3.3). When expiration dates were compared, only Tetric Flow showed a statistically significant difference (P < 0.05). Regardless of the expiration date, ΔOP values for all composites increased after AAA, but not significantly (P > 0.05). The expired Tetric Flow had the highest DOC values (71.42% ± 4.21) before AAA, significantly different than that of the other composites (P > 0.05). It was concluded that both expiration date and AAA affected the properties of the composites tested. PMID:24192739

  19. Monitoring of pigmented and wooden surfaces in accelerated ageing processes by FT-Raman spectroscopy and multivariate control charts.

    PubMed

    Marengo, Emilio; Robotti, Elisa; Liparota, Maria Cristina; Gennaro, Maria Carla

    2004-07-01

    Two of the most suitable analytical techniques used in the field of cultural heritage are NIR (near-infrared) and Raman spectroscopy. FT-Raman spectroscopy coupled to multivariate control charts is applied here for the development of a new method for monitoring the conservation state of pigmented and wooden surfaces. These materials were exposed to different accelerated ageing processes in order to evaluate the effect of the applied treatments on the goods surfaces. In this work, a new approach based on the principles of statistical process control (SPC) to the monitoring of cultural heritage, has been developed: the conservation state of samples simulating works-of-art has been treated like an industrial process, monitored with multivariate control charts, owing to the complexity of the spectroscopic data collected. The Raman spectra were analysed by principal component analysis (PCA) and the relevant principal components (PCs) were used for constructing multivariate Shewhart and cumulative sum (CUSUM) control charts. These tools were successfully applied for the identification of the presence of relevant modifications occurring on the surfaces. CUSUM charts however proved to be more effective in the identification of the exact beginning of the applied treatment. In the case of wooden boards, where a sufficient number of PCs were available, simultaneous scores monitoring and residuals tracking (SMART) charts were also investigated. The exposure to a basic attack and to high temperatures produced deep changes on the wooden samples, clearly identified by the multivariate Shewhart, CUSUM and SMART charts. A change on the pigment surface was detected after exposure to an acidic solution and to the UV light, while no effect was identified on the painted surface after the exposure to natural atmospheric events. PMID:18969526

  20. World Health Organization generic protocol to assess drug-resistant HIV among children <18 months of age and newly diagnosed with HIV in resource-limited countries.

    PubMed

    Bertagnolio, Silvia; Penazzato, Martina; Jordan, Michael R; Persaud, Deborah; Mofenson, Lynne M; Bennett, Diane E

    2012-05-01

    Increased use of nonnucleoside reverse transcriptase inhibitors (NNRTIs) in pregnant and breastfeeding women will result in fewer children infected with human immunodeficiency virus (HIV). However, among children infected despite prevention of mother-to-child transmission (PMTCT), a substantial proportion will acquire NNRTI-resistant HIV, potentially compromising response to NNRTI-based antiretroviral therapy (ART). In countries scaling up PMTCT and pediatric ART programs, it is crucial to assess the proportion of young children with drug-resistant HIV to improve health outcomes and support national and global decision making on optimal selection of pediatric first-line ART. This article summarizes a new World Health Organization surveillance protocol to assess resistance using remnant dried blood spot specimens from a representative sample of children aged <18 months being tested for early infant diagnosis.

  1. Opportunistic detection of atrial fibrillation in subjects aged 65 years or older in primare care: a randomised clinical trial of efficacy. DOFA-AP study protocol

    PubMed Central

    2012-01-01

    Background Clinical Practice Guidelines recommend using peripheral blood pulse measuring as a screening test for Atrial Fibrillation. However, there is no adequate evidence supporting the efficacy of such procedure in primary care clinical practice. This paper describes a study protocol designed to verify whether early opportunistic screening for Atrial Fibrillation by measuring blood pulse is more effective than regular practice in subjects aged 65 years attending primary care centers. Methods/design An cluster-randomized controlled trial conducted in Primary Care Centers of the Spanish National Health Service. A total of 269 physicians and nurses will be allocated to one of the two arms of the trial by stratified randomization with a 3:2 ratio (three practitioners will be assigned to the Control Group for every two practitioners assigned to the Experimental Group). As many as 12 870 patients aged 65 years or older and meeting eligibility criteria will be recruited (8 580 will be allocated to the Experimental Group and 4 290 to the Control Group). Randomization and allocation to trial groups will be carried out by a central computer system. The Experimental Group practitioners will conduct an opportunistic case finding for patients with Atrial Fibrillation, while the Control Group practitioners will follow the regular guidelines. The first step will be finding new Atrial Fibrillation cases. A descriptive inferential analysis will be performed (bivariate and multivariate by multilevel logistic regression analysis). Discussion If our hypothesis is confirmed, we expect Primary Care professionals to take a more proactive approach and adopt a new protocol when a patient meeting the established screening criteria is identified. Finally, we expect this measure to be incorporated into Clinical Practice Guidelines. Trial registration The study is registered as NCT01291953 (ClinicalTrials.gob) PMID:23130754

  2. Study protocol: the relation of birth weight and infant growth trajectories with physical fitness, physical activity and sedentary behavior at 8-9 years of age - the ABCD study

    PubMed Central

    2013-01-01

    Background Low birth weight and accelerated infant growth have been identified as independent risk factors for childhood and adult obesity and cardiovascular disease. This led to the ‘Developmental Origins of Health and Disease’ (DOHaD) hypothesis, stating that environmental factors during pregnancy and early postnatal life affect disease risk in later life. There is growing evidence that perinatal factors may influence adult health through the programming of energy balance regulation, including sedentary behavior and physical activity. The present study focuses on the influence of birth weight and infant growth on physical fitness, physical activity and sedentary behavior in 8-9 year old children, as this might partly explain the higher obesity and cardiovascular risk associated with low birth weight and accelerated infant growth. In addition, this study provides the opportunity for a validation study of a linguistic and cross-cultural translated physical activity questionnaire compared to accelerometer data. This article describes the study protocol for this study. Methods/Design This is a study embedded in the Amsterdam Born Children and their Development (ABCD) birth cohort. In 200 children of Dutch ethnicity, physical fitness, physical activity and sedentary behavior were assessed at age 8-9. We measured aerobic fitness using the 20 meter multistage shuttle run test, and neuromuscular fitness using the standing broad jump and handgrip strength test. Sedentary behavior and physical activity levels were measured using accelerometry. All children also completed a translated physical activity questionnaire, the scores of which will be compared to accelerometry data to assess the construct validity of the questionnaire in Dutch school-aged children. Discussion This study will be the first population-based prospective cohort study to address the association of both prenatal and postnatal growth with physical fitness and objectively-assessed physical activity and

  3. BENCHMARK ACCELERATED AGING OF HARVESTED HYPALON/EPR AND CSPE/XLPE POWER AND I&C CABLE IN NUCLEAR POWER PLANTS

    SciTech Connect

    Duckworth, Robert C; Fifield, Dr Leonard S

    2016-01-01

    As part of the Light Water Reactor and Sustainability (LWRS) program in the U.S. Department of Energy (DOE) Office of Nuclear Energy, material aging and degradation research is currently geared to support the long-term operation of existing nuclear power plants (NPPs) as they move beyond their initial 40 year licenses. The goal of this research is to provide information so that NPPs can develop aging management programs (AMPs) to address replacement and monitoring needs as they look to operate for 20 years, and in some cases 40 years, beyond their initial operating lifetimes. For cable insulation and jacket materials that support instrument, control, and safety systems, accelerated aging data are needed to determine priorities in cable aging management programs. Before accelerated thermal and radiation aging of harvested, representative cable insulation and jacket materials, the benchmark performance of a new test capability at Oak Ridge National Laboratory (ORNL) was evaluated for temperatures between 70 and 135 C, dose rates between 100 and 500 Gy/h, and accumulated doses up to 20 kGy, Samples that were characterized and are representative of current materials in use were harvested from the Callaway NPP near Fulton, Missouri, and the San Onofre NPP north of San Diego, California. From the Callaway NPP, a multiconductor control rod cable manufactured by Boston Insulated Wire (BIW), with a Hypalon/ chorolosulfonated polyethylene (CSPE) jacket and ethylene-propylene rubber (EPR) insulation, was harvested from the auxiliary space during a planned outage in 2013. This cable was placed into service when the plant was started in 1984. From the San Onofre NPP, a Rockbestos Firewall III (FRIII) cable with a Hypalon/ CSPE jacket with cross-linked polyethylene (XLPE) insulation was harvested from an on-site, climate-controlled storage area. This conductor, which was never placed into service, was procured around 2007 in anticipation of future operation that did not occur

  4. Evaluation of HVDC cables for the St. Lawrence crossing of Hydro-Quebec 500 kV DC Line. Part 1; Dielectric and accelerated aging tests on prototypes

    SciTech Connect

    Coudere, D.; Trinh, N.G.; Belec, M.; Chaaban, M.; Leduc, J.; Beausejour, Y. )

    1992-04-01

    This paper describes the dielectric and accelerated aging tests on prototype {plus minus}500 kV dc oil-filled self-contained cables. The extensive test program was required to evaluate the High-Voltage cables for the St. Lawrence river crossing of the {plus minus}500 kV Quebec-New England HVDC power transmission system. The paper relates the main elements of the test program. It describes the required insulation levels, the characteristics of the cables supplied by three different manufacturers, as well as the cables' installation for the type tests and accelerated aging tests. Details of the test program and procedures followed to carry out the tests are given. Findings of the tests are also reported.

  5. Nutrition interventions for children aged less than 5 years following natural disasters: a systematic review protocol

    PubMed Central

    Pradhan, Pranil Man Singh; Dhital, Rolina; Subhani, Huma

    2015-01-01

    Introduction Malnutrition among children is a serious public health problem in the aftermath of any natural disaster. We will review the various nutrition interventions for children aged <5 years in countries where natural disasters occurred and analyse the effect on nutrition-related outcomes. Methods and analysis We will conduct a systematic review on nutrition intervention studies following natural disasters that were published between January 2000 and December 2015. Study selection will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The Cochrane Risk of Bias (RoB) tool will be used for randomised controlled trials and Risk of Bias Assessment for Non-Randomized Studies (RoBANS) will be used for non-randomised studies. The quality of evidence will be assessed using Grading of Recommendations Assessment, Development, and Evaluation (GRADE) guidelines. If sufficient data are available, we will conduct meta-analyses to establish the relationship between nutrition interventions and nutrition outcome indicators. All statistical analyses will be performed using Review Manager (Rev Man) V.5.3 for Windows. Heterogeneity of the data will be tested using the standard χ2 test. A fixed-effect model will be used for the studies with high heterogeneity (p value>0.10, I2≤50%). For dichotomous and continuous data, relative risk (RR) and mean difference with 95% CI will be used respectively. Subgroup analysis will be performed for studies with low heterogeneity (p value ≤0.10). We will use Z score with the level of significance set at p value <0.05 to test the total effect. Funnel plots will be used to detect publication bias. Ethics and dissemination As primary data will not be collected, formal ethical approval will not be required. The results will be disseminated by publication in peer-reviewed journals, conference presentations and the media. Registration details International Prospective Register for Systematic

  6. Obesity-induced chronic inflammation in high fat diet challenged C57BL/6J mice is associated with acceleration of age-dependent renal amyloidosis.

    PubMed

    van der Heijden, Roel A; Bijzet, Johan; Meijers, Wouter C; Yakala, Gopala K; Kleemann, Robert; Nguyen, Tri Q; de Boer, Rudolf A; Schalkwijk, Casper G; Hazenberg, Bouke P C; Tietge, Uwe J F; Heeringa, Peter

    2015-11-13

    Obesity-induced inflammation presumably accelerates the development of chronic kidney diseases. However, little is known about the sequence of these inflammatory events and their contribution to renal pathology. We investigated the effects of obesity on the evolution of age-dependent renal complications in mice in conjunction with the development of renal and systemic low-grade inflammation (LGI). C57BL/6J mice susceptible to develop age-dependent sclerotic pathologies with amyloid features in the kidney, were fed low (10% lard) or high-fat diets (45% lard) for 24, 40 and 52 weeks. HFD-feeding induced overt adiposity, altered lipid and insulin homeostasis, increased systemic LGI and adipokine release. HFD-feeding also caused renal upregulation of pro-inflammatory genes, infiltrating macrophages, collagen I protein, increased urinary albumin and NGAL levels. HFD-feeding severely aggravated age-dependent structural changes in the kidney. Remarkably, enhanced amyloid deposition rather than sclerosis was observed. The degree of amyloidosis correlated significantly with body weight. Amyloid deposits stained positive for serum amyloid A (SAA) whose plasma levels were chronically elevated in HFD mice. Our data indicate obesity-induced chronic inflammation as a risk factor for the acceleration of age-dependent renal amyloidosis and functional impairment in mice, and suggest that obesity-enhanced chronic secretion of SAA may be the driving factor behind this process.

  7. Comparative study of ageing, heat treatment and accelerated carbonation for stabilization of municipal solid waste incineration bottom ash in view of reducing regulated heavy metal/metalloid leaching.

    PubMed

    Santos, Rafael M; Mertens, Gilles; Salman, Muhammad; Cizer, Özlem; Van Gerven, Tom

    2013-10-15

    This study compared the performance of four different approaches for stabilization of regulated heavy metal and metalloid leaching from municipal solid waste incineration bottom ash (MSWI-BA): (i) short term (three months) heap ageing, (ii) heat treatment, (iii) accelerated moist carbonation, and (iv) accelerated pressurized slurry carbonation. Two distinct types of MSWI-BA were tested in this study: one originating from a moving-grate furnace incineration operation treating exclusively household refuse (sample B), and another originating from a fluid-bed furnace incineration operation that treats a mixture of household and light industrial wastes (sample F). The most abundant elements in the ashes were Si (20-27 wt.%) and Ca (16-19 wt.%), followed by significant quantities of Fe, Al, Na, S, K, Mg, Ti, and Cl. The main crystalline substances present in the fresh ashes were Quartz, Calcite, Apatite, Anhydrite and Gehlenite, while the amorphous fraction ranged from 56 to 73 wt.%. The leaching values of all samples were compared to the Flemish (NEN 7343) and the Walloon (DIN 38414) regulations from Belgium. Batch leaching of the fresh ashes at natural pH showed that seven elements exceeded at least one regulatory limit (Ba, Cr, Cu, Mo, Pb, Se and Zn), and that both ashes had excess basicity (pH > 12). Accelerated carbonation achieved significant reduction in ash basicity (9.3-9.9); lower than ageing (10.5-12.2) and heat treatment (11.1-12.1). For sample B, there was little distinction between the leaching results of ageing and accelerated carbonation with respect to regulatory limits; however carbonation achieved comparatively lower leaching levels. Heat treatment was especially detrimental to the leaching of Cr. For sample F, ageing was ineffective and heat treatment had marginally better results, while accelerated carbonation delivered the most effective performance, with slurry carbonation meeting all DIN limits. Slurry carbonation was deemed the most

  8. Soiling of building envelope surfaces and its effect on solar reflectance – Part II: Development of an accelerated aging method for roofing materials

    SciTech Connect

    Sleiman, Mohamad; Kirchstetter, Thomas W.; Berdahl, Paul; Gilbert, Haley E.; Quelen, Sarah; Marlot, Lea; Preble, Chelsea V.; Chen, Sharon; Montalbano, Amandine; Rosseler, Olivier; Akbari, Hashem; Levinson, Ronnen; Destaillats, Hugo

    2014-01-09

    Highly reflective roofs can decrease the energy required for building air conditioning, help mitigate the urban heat island effect, and slow global warming. However, these benefits are diminished by soiling and weathering processes that reduce the solar reflectance of most roofing materials. Soiling results from the deposition of atmospheric particulate matter and the growth of microorganisms, each of which absorb sunlight. Weathering of materials occurs with exposure to water, sunlight, and high temperatures. This study developed an accelerated aging method that incorporates features of soiling and weathering. The method sprays a calibrated aqueous soiling mixture of dust minerals, black carbon, humic acid, and salts onto preconditioned coupons of roofing materials, then subjects the soiled coupons to cycles of ultraviolet radiation, heat and water in a commercial weatherometer. Three soiling mixtures were optimized to reproduce the site-specific solar spectral reflectance features of roofing products exposed for 3 years in a hot and humid climate (Miami, Florida); a hot and dry climate (Phoenix, Arizona); and a polluted atmosphere in a temperate climate (Cleveland, Ohio). A fourth mixture was designed to reproduce the three-site average values of solar reflectance and thermal emittance attained after 3 years of natural exposure, which the Cool Roof Rating Council (CRRC) uses to rate roofing products sold in the US. This accelerated aging method was applied to 25 products₋single ply membranes, factory and field applied coatings, tiles, modified bitumen cap sheets, and asphalt shingles₋and reproduced in 3 days the CRRC's 3-year aged values of solar reflectance. In conclusion, this accelerated aging method can be used to speed the evaluation and rating of new cool roofing materials.

  9. QM/MM Protocol for Direct Molecular Dynamics of Chemical Reactions in Solution: The Water-Accelerated Diels-Alder Reaction.

    PubMed

    Yang, Zhongyue; Doubleday, Charles; Houk, K N

    2015-12-01

    We describe a solvent-perturbed transition state (SPTS) sampling scheme for simulating chemical reaction dynamics in condensed phase. The method, adapted from Truhlar and Gao's ensemble-averaged variational transition state theory, includes the effect of instantaneous solvent configuration on the potential energy surface of the reacting system (RS) and allows initial conditions for the RS to be sampled quasiclassically by TS normal mode sampling. We use a QM/MM model with direct dynamics, in which QM forces of the RS are computed at each trajectory point. The SPTS scheme is applied to the acceleration of the Diels-Alder reaction of cyclopentadiene (CP) + methyl vinyl ketone (MVK) in water. We explored the effect of the number of SPTS and of solvent box size on the distribution of bond lengths in the TS. Statistical sampling of the sampling was achieved when distribution of forming bond lengths converged. We describe the region enclosing the partial bond lengths as the transition zone. Transition zones in the gas phase, SMD implicit solvent, QM/MM, and QM/MM+QM (3 water molecules treated by QM) vary according to the ability of the medium to stabilize zwitterionic structures. Mean time gaps between formation of C-C bonds vary from 11 fs for gas phase to 25 fs for QM/MM+QM. Mean H-bond lengths to O(carbonyl) in QM/MM+QM are 0.14 Å smaller at the TS than in MVK reactant, and the mean O(carbonyl)-H(water)-O(water) angle of H-bonds at the TS is 10° larger than in MVK reactant.

  10. Efficient plant regeneration protocol through callus for Saussurea obvallata (DC.) Edgew. (Asteraceae): effect of explant type, age and plant growth regulators.

    PubMed

    Dhar, Uppeandra; Joshi, Mitali

    2005-06-01

    A callus induction and in vitro plantlet regeneration system for the endangered state flower of Uttaranchal (Saussurea obvallata) was optimized by studying the influence of explant type (root, hypocotyl, cotyledon and leaf), age and different concentrations of plant growth regulators. Explants from 10 to 15-day-old seedlings showed maximum callus induction. Callus formation and shoot differentiation was initiated on Murashige-Skoog (MS) medium containing 6-benzyladenine (BA) and alpha-naphthalene acetic acid (NAA) in all explant types. The best results were obtained using leaf explants: 100% callusing was achieved in MS medium supplemented with 2.5 microM BA and 1.0 microM NAA, and 100% differentiation along with a multiplication rate of 12 shoots per explant with a combination of 5.0 microM BA and 1.0 microM NAA. However, the results reflected the existence of high inter-explant variability in response to growth regulators. In vitro rooting of shoots was achieved at an efficiency of 100% in one-half strength MS medium supplemented with 2.5 microM indole-3-butyric acid. Application of this protocol has potential for mass multiplication of the target species in a limited time period.

  11. Obese parents – obese children? Psychological-psychiatric risk factors of parental behavior and experience for the development of obesity in children aged 0–3: study protocol

    PubMed Central

    2013-01-01

    Background The incidences of childhood overweight and obesity have increased substantially and with them the prevalence of associated somatic and psychiatric health problems. Therefore, it is important to identify modifiable risk factors for early childhood overweight in order to develop effective prevention or intervention programs. Besides biological factors, familial interactions and parental behavioral patterns may influence children’s weight development. Longitudinal investigation of children at overweight risk could help to detect significant risk and protective factors. We aim to describe infants’ weight development over time and identify risk and protective factors for the incidence of childhood obesity. Based on our findings we will draw up a risk model that will lay the foundation for an intervention/prevention program. Methods/Design We present the protocol of a prospective longitudinal study in which we investigate families with children aged from 6 months to 47 months. In half of the families at least one parent is obese (risk group), in the other half both parents are normal weight (control group). Based on developmental and health-psychological models, we consider measurements at three levels: the child, the parents and parent–child-relationship. Three assessment points are approximately one year apart. At each assessment point we evaluate the psychological, social, and behavioral situation of the parents as well as the physical and psychosocial development of the child. Parents are interviewed, fill in questionnaires, and take part in standardized interaction tasks with their child in a feeding and in a playing context in our research laboratory. The quality of these video-taped parent–child interactions is assessed by analyzing them with standardized, validated instruments according to scientific standards. Discussion Strengths of the presented study are the prospective longitudinal design, the multi-informant approach, including the

  12. Using patients’ experiences of adverse events to improve health service delivery and practice: protocol of a data linkage study of Australian adults age 45 and above

    PubMed Central

    Walton, Merrilyn; Smith-Merry, Jennifer; Harrison, Reema; Manias, Elizabeth; Iedema, Rick; Kelly, Patrick

    2014-01-01

    Introduction Evidence of patients’ experiences is fundamental to creating effective health policy and service responses, yet is missing from our knowledge of adverse events. This protocol describes explorative research redressing this significant deficit; investigating the experiences of a large cohort of recently hospitalised patients aged 45 years and above in hospitals in New South Wales (NSW), Australia. Methods and analysis The 45 and Up Study is a cohort of 265 000 adults aged 45 years and above in NSW. Patients who were hospitalised between 1 January and 30 June 2014 will be identified from this cohort using data linkage and a random sample of 20 000 invited to participate. A cross-sectional survey (including qualitative and quantitative components) will capture patients’ experiences in hospital and specifically of adverse events. Approximately 25% of respondents are likely to report experiencing an adverse event. Quantitative components will capture the nature and type of events as well as common features of patients’ experiences. Qualitative data provide contextual knowledge of their condition and care and the impact of the event on individuals. Respondents who do not report an adverse event will report their experience in hospital and be the control group. Statistical and thematic analysis will be used to present a patient perspective of their experiences in hospital; the characteristics of patients experiencing an adverse event; experiences of information sharing after an event (open disclosure) and the other avenues of redress pursued. Interviews with key policymakers and a document analysis will be used to create a map of the current practice. Ethics and dissemination Dissemination via a one-day workshop, peer-reviewed publications and conference presentations will enable effective clinical responses and service provision and policy responses to adverse events to be developed. PMID:25311039

  13. The anti-aging effects of LW-AFC via correcting immune dysfunctions in senescence accelerated mouse resistant 1 (SAMR1) strain

    PubMed Central

    Wang, Jianhui; Cheng, Xiaorui; Zhang, Xiaorui; Cheng, Junping; Xu, Yiran; Zeng, Ju; Zhou, Wenxia; Zhang, Yongxiang

    2016-01-01

    Although there were considerable advances in the anti-aging medical field, it is short of therapeutic drug for anti-aging. Mounting evidence indicates that the immunosenescence is the key physiopathological mechanism of aging. This study showed the treatment of LW-AFC, an herbal medicine, decreased the grading score of senescence, increased weight, prolonged average life span and ameliorated spatial memory impairment in 12- and 24-month-old senescence accelerated mouse resistant 1 (SAMR1) strain. And these anti-aging effects of LW-AFC were more excellent than melatonin. The administration of LW-AFC enhanced ConA- and LPS-induced splenocyte proliferation in aged SAMR1 mice. The treatment of LW-AFC not only reversed the decreased the proportions of helper T cells, suppressor T cells and B cells, the increased regulatory T cells in the peripheral blood of old SAMR1 mice, but also could modulate the abnormal secretion of IL-1β, IL-2, IL-6, IL-17, IL-23, GM-CSF, IFN-γ, TNF-α, TNF-β, RANTES, eotaxin, MCP-1, IL-4, IL-5, IL-10 and G-CSF. These data indicated that LW-AFC reversed the immunosenescence status by restoring immunodeficiency and decreasing chronic inflammation and suggested LW-AFC may be an effective anti-aging agent. PMID:27105505

  14. The influence of chronological age on periods of accelerated adaptation of stretch-shortening cycle performance in pre and postpubescent boys.

    PubMed

    Lloyd, Rhodri S; Oliver, Jon L; Hughes, Michael G; Williams, Craig A

    2011-07-01

    Although it is suggested that periods of naturally occurring accelerated adaptation may exist for various physical parameters, it would appear that no such evidence exists for stretch-shortening cycle (SSC) development. Two hundred and fifty male youths aged 7-17 years were tested for squat (SJ) and countermovement jump (CMJ) height, reactive strength index (RSI), and leg stiffness, with analyses of variance used to establish any significant between-group differences. Additionally, to ascertain the existence of periods of accelerated adaptation, inferences were made about the magnitudes of change between consecutive chronological age groups in relation to the smallest worthwhile change. The largest mean differences (±90% confidence limits) occurred between age groups 10 and 11 (G10-G11) for squat jump (SJ) height (21.61 ± 12.08-31.94%), CMJ height (20.80 ± 11.1-44.1%), and RSI (26.51 ± 11.07-44.10%); and between G12 and G13 for SJ (15.31 ± 7.47-23.73%) and CMJ (16.09 ± 7.50-25.38%) height. Negative mean differences occurred between G11 and G12 for SJ height (-1.32 ± -9.30 to 7.37%), CMJ jump height (-7.68 ± -15.15 to 0.45%) and RSI (-11.48 ± -22.21 to 0.74%); and between G10 and G11 for leg stiffness (-8.87 ± -18.85 to 2.34%). It would appear almost certain that windows of accelerated adaptation may exist for SJ and CMJ height and RSI in male youths; however, leg stiffness results would suggest that fast-SSC function may follow a different developmental trend.

  15. Communications protocol

    NASA Technical Reports Server (NTRS)

    Zhou, Xiaoming (Inventor); Baras, John S. (Inventor)

    2010-01-01

    The present invention relates to an improved communications protocol which increases the efficiency of transmission in return channels on a multi-channel slotted Alohas system by incorporating advanced error correction algorithms, selective retransmission protocols and the use of reserved channels to satisfy the retransmission requests.

  16. Australian Cerebral Palsy Child Study: protocol of a prospective population based study of motor and brain development of preschool aged children with cerebral palsy

    PubMed Central

    2013-01-01

    . Discussion This protocol describes a large population-based study of early motor development and brain structure in a representative sample of preschool aged children with CP, using direct clinical assessment. The results of this study will be published in peer reviewed journals and presented at relevant international conferences. Trial registration Australia and New Zealand Clinical Trials Register (ACTRN1261200169820) PMID:23758951

  17. Evidence that glucose metabolism is decreased in the cerebrum of aged female senescence-accelerated mouse; possible involvement of a low hexokinase activity.

    PubMed

    Kurokawa, T; Sato, E; Inoue, A; Ishibashi, S

    1996-08-16

    d-Glucose metabolism in cerebral cells prepared from aged senescence-accelerated mouse (SAM), was investigated in consideration of a sex difference. The production of 14CO2 from 6-[14C]D-glucose was reduced in female senescence-accelerated-prone mouse (SAMP) 8, a prone substrain, in comparison with that in female senescence-accelerated-resistant mouse (SAMR) 2, a control substrain, whereas there was no difference in males. The 2-deoxy-D-glucose uptake into cerebral cells from female SAMP8 was also lower than that of control mice. But, the 3-O-methyl-D-glucose uptake in SAMP8 was higher than that of SAMR2, suggesting that the low hexokinase activity was involved in the decreased glucose metabolism in cerebrum of SAMP8 females irrespective of glucose transporter. This possibility was supported by the finding that the contents of glucose 6-phosphate produced from glucose added to cerebral cells from SAMP8 was lower than that in ICR mice. PMID:8873128

  18. Phenolic composition of vinegars over an accelerated aging process using different wood species (acacia, cherry, chestnut, and oak): effect of wood toasting.

    PubMed

    Cerezo, Ana B; Álvarez-Fernández, M Antonia; Hornedo-Ortega, Ruth; Troncoso, Ana M; García-Parrilla, M Carmen

    2014-05-14

    Wood shavings are widely employed in vinegar making to reduce aging time. Accordingly, this study aims to evaluate the effects of using shavings from different wood species (acacia, cherry, chestnut, and oak) and of toasting on the release of phenolic compounds into vinegar during the aging process. The study involved aging vinegars using previously toasted shavings and untoasted ones, at 0.5% and 1% (w/v), and collecting samples at 15 and 30 days. The phenolic compounds were analyzed by LC-DAD during the aging process. As a result, wood markers naringenin and kaempferol (cherry), robinetin and fustin (acacia), and isovanillin (oak) were identified for the first time in vinegars. The results also showed that toasting wood shavings decreases the concentration of most flavonoid wood markers (e.g., (+)-taxifolin, naringenin, and fustin) in vinegar, but that it is essential for the highest releases of aldehyde compounds (syringaldehyde, protocatechualdehyde, and vanillin). Remarkably, 15 days was sufficient to obtain the highest increases of most polyphenol compounds in the vinegar. Statistical analysis (linear discriminant analysis) proved that the phenolic compounds identified in vinegars are useful for discriminating vinegars regarding the wood species of the shavings used to accelerate aging.

  19. Aging and Tennis Playing in a Coincidence-Timing Task with an Accelerating Object: The Role of Visuomotor Delay

    ERIC Educational Resources Information Center

    Lobjois, Regis; Benguigui, Nicolas; Bertsch, Jean

    2005-01-01

    The purpose of the present study was to determine whether playing a specific ball sport, such as tennis, could maintain the coincidence-timing (CT) performance of older adults at a similar level to that of younger ones. To address this question, tennis players and nonplayers of three different age ranges (ages 20-30, 60-70, and 70-80 years)…

  20. The effects of free and bonded sulfur both in the presence and absence of vulcanization accelerators on the rheological, technological, aging, and thermal stability of asphalts

    SciTech Connect

    Onabajo, A.; Kopsch, H.

    1987-01-01

    Rheological and technological experiments have been carried out on sulfur-modified asphalts in the temperature range of 353 K to 453 K over a wide range of shear rates (0-4800 sec/sup -1/). The results indicated that the activation energy of the viscous flow increased with increasing amount of bonded sulfur. The irreversible shear degradation observed in sulfur-modified asphalts is caused by the high shear forces which rupture the aggregated molecules. Thermogravimetric analysis and aging experiments on asphalts and their sulfurized products, containing varying amounts of free sulfur (0-5.5 wt.-%) and vulcanization accelerators (0.5-2.5 wt.-%), have shown that mixes containing vulcanization accelerators have higher thermal stabilities and are more resistant to thermal and non-thermal aging than the unaccelerated asphalt-sulfur mixed prepared at the same or higher temperatures. The changes in the rheological and physical properties of the mixes with time is not only explained by the changes in the physical state of unreacted free sulfur, that is, from plastic to crystalline state (physical process), but also attributable to the effect of chemical reactions.

  1. Accelerated aging tests on ENEA-ASE solar coating for receiver tube suitable to operate up to 550 °C

    NASA Astrophysics Data System (ADS)

    Antonaia, A.; D'Angelo, A.; Esposito, S.; Addonizio, M. L.; Castaldo, A.; Ferrara, M.; Guglielmo, A.; Maccari, A.

    2016-05-01

    A patented solar coating for evacuated receiver, based on innovative graded WN-AlN cermet layer, has been optically designed and optimized to operate at high temperature with high performance and high thermal stability. This solar coating, being designed to operate in solar field with molten salt as heat transfer fluid, has to be thermally stable up to the maximum temperature of 550 °C. With the aim of determining degradation behaviour and lifetime prediction of the solar coating, we chose to monitor the variation of the solar absorptance αs after each thermal annealing cycle carried out at accelerated temperatures under vacuum. This prediction method was coupled with a preliminary Differential Thermal Analysis (DTA) in order to give evidence for any chemical-physical coating modification in the temperature range of interest before performing accelerated aging tests. In the accelerated aging tests we assumed that the temperature dependence of the degradation processes could be described by Arrhenius behaviour and we hypothesized that a linear correlation occurs between optical parameter variation rate (specifically, Δαs/Δt) and degradation process rate. Starting from Δαs/Δt values evaluated at 650 and 690 °C, Arrhenius plot gave an activation energy of 325 kJ mol-1 for the degradation phenomenon, where the prediction on the coating degradation gave a solar absorptance decrease of only 1.65 % after 25 years at 550 °C. This very low αs decrease gave evidence for an excellent stability of our solar coating, also when employed at the maximum temperature (550 °C) of a solar field operating with molten salt as heat transfer fluid.

  2. Muscle-specific inositide phosphatase (MIP/MTMR14) is reduced with age and its loss accelerates skeletal muscle aging process by altering calcium homeostasis

    PubMed Central

    Romero-Suarez, Sandra; Shen, Jinhua; Brotto, Leticia; Hall, Todd; Mo, ChengLin; Valdivia, Héctor H.; Andresen, Jon; Wacker, Michael; Nosek, Thomas M.; Qu, Cheng-Kui; Brotto, Marco

    2010-01-01

    We have recently reported that a novel muscle-specific inositide phosphatase (MIP/MTMR14) plays a critical role in [Ca2+]i homeostasis through dephosphorylation of sn-1-stearoyl-2-arachidonoyl phosphatidylinositol (3,5) bisphosphate (PI(3,5)P2). Loss of function mutations in MIP have been identified in human centronuclear myopathy. We developed a MIP knockout (MIPKO) animal model and found that MIPKO mice were more susceptible to exercise-induced muscle damage, a trademark of muscle functional changes in older subjects. We used wild-type (Wt) mice and MIPKO mice to elucidate the roles of MIP in muscle function during aging. We found MIP mRNA expression, MIP protein levels, and MIP phosphatase activity significantly decreased in old Wt mice. The mature MIPKO mice displayed phenotypes that closely resembled those seen in old Wt mice: i) decreased walking speed, ii) decreased treadmill activity, iii) decreased contractile force, and iv) decreased power generation, classical features of sarcopenia in rodents and humans. Defective Ca2+ homeostasis is also present in mature MIPKO and old Wt mice, suggesting a putative role of MIP in the decline of muscle function during aging. Our studies offer a new avenue for the investigation of MIP roles in skeletal muscle function and as a potential therapeutic target to treat aging sarcopenia. PMID:20817957

  3. Dietary (-)-Epigallocatechin-3-gallate Supplementation Counteracts Aging-Associated Skeletal Muscle Insulin Resistance and Fatty Liver in Senescence-Accelerated Mouse.

    PubMed

    Liu, Hung-Wen; Chan, Yin-Ching; Wang, Ming-Fu; Wei, Chu-Chun; Chang, Sue-Joan

    2015-09-30

    Aging is accompanied by pathophysiological changes including insulin resistance and fatty liver. Dietary supplementation with (-)-epigallocatechin-3-gallate (EGCG) improves insulin sensitivity and attenuates fatty liver disease. We hypothesized that EGCG could effectively modulate aging-associated changes in glucose and lipid metabolism in senescence-accelerated mice (SAM) prone 8 (SAMP8). Higher levels of glucose, insulin, and free fatty acid, inhibited Akt activity, and decreased glucose transporter 4 (GLUT4) expression were observed in SAMP8 mice compared to the normal aging group, SAM resistant 1 mice. EGCG supplementation for 12 weeks successfully decreased blood glucose and insulin levels via restoring Akt activity and GLUT4 expression and stimulating AMPKα activation in skeletal muscle. EGCG up-regulated genes involved in mitochondrial biogenesis and subsequently restored mitochondrial DNA copy number in skeletal muscle of SAMP8 mice. Decreased adipose triglyceride lipase and increased sterol regulatory element binding proteins-1c (SREBP-1c) and carbohydrate responsive element binding protein at mRNA levels were observed in SAMP8 mice in accordance with hepatocellular ballooning and excess lipid accumulation. The pevention of hepatic lipid accumulation by EGCG was mainly attributed to down-regulation of mTOR and SREBP-1c-mediated lipid biosynthesis via suppression of the positive regulator, Akt, and activation of the negative regulator, AMPKα, in the liver. EGCG beneficially modulates glucose and lipid homeostasis in skeletal muscle and liver, leading to alleviation of aging-associated metabolic disorders.

  4. The Relationship Between Maillard Reaction Product Formation and the Strength of Griege Yarns Subjected to Accelerated Ageing Conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous work examining the effect of ageing on cotton fiber surface chemical and HVI properties, yarn processing performance, and yarn quality showed that cotton bales stored for extended periods exhibit significant changes in a number of these variables including primarily surface sugar content, H...

  5. Age-dependent capacity to accelerate protein synthesis dictates the extent of compensatory growth in skeletal muscle following undernutrition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In both humans and animals, impaired growth during early life compromises adult lean body mass and muscle strength despite skeletal muscle’s large regenerative capacity. To identify the significance of developmental age on skeletal muscle’s capacity for catch-up growth following an episode of under ...

  6. Exposure to 56Fe irradiation accelerates normal brain aging and produces deficits in spatial learning and memory

    NASA Astrophysics Data System (ADS)

    Shukitt-Hale, Barbara; Casadesus, Gemma; Carey, Amanda N.; Rabin, Bernard M.; Joseph, James A.

    Previous studies have shown that radiation exposure, particularly to particles of high energy and charge (HZE particles) such as 56Fe, produces deficits in spatial learning and memory. These adverse behavioral effects are similar to those seen in aged animals. It is possible that these shared effects may be produced by the same mechanism. For example, an increased release of reactive oxygen species, and the subsequent oxidative stress and inflammatory damage caused to the central nervous system, is likely responsible for the deficits seen in aging and following irradiation. Therefore, dietary antioxidants, such as those found in fruits and vegetables, could be used as countermeasures to prevent the behavioral changes seen in these conditions. Both aged and irradiated rats display cognitive impairment in tests of spatial learning and memory such as the Morris water maze and the radial arm maze. These rats have decrements in the ability to build spatial representations of the environment, and they utilize non-spatial strategies to solve tasks. Furthermore, they show a lack of spatial preference, due to a decline in the ability to process or retain place (position of a goal with reference to a “map” provided by the configuration of numerous cues in the environment) information. These declines in spatial memory occur in measures dependent on both reference and working memory, and in the flexibility to reset mental images. These results show that irradiation with 56Fe high-energy particles produces age-like decrements in cognitive behavior that may impair the ability of astronauts, particularly middle-aged ones, to perform critical tasks during long-term space travel beyond the magnetosphere.

  7. Shortened estrous cycle length, increased FSH levels, FSH variance, oocyte spindle aberrations, and early declining fertility in aging senescence-accelerated mouse prone-8 (SAMP8) mice: concomitant characteristics of human midlife female reproductive aging.

    PubMed

    Bernstein, Lori R; Mackenzie, Amelia C L; Kraemer, Duane C; Morley, John E; Farr, Susan; Chaffin, Charles L; Merchenthaler, István

    2014-06-01

    Women experience a series of specific transitions in their reproductive function with age. Shortening of the menstrual cycle begins in the mid to late 30s and is regarded as the first sign of reproductive aging. Other early changes include elevation and increased variance of serum FSH levels, increased incidences of oocyte spindle aberrations and aneuploidy, and declining fertility. The goal of this study was to investigate whether the mouse strain senescence-accelerated mouse-prone-8 (SAMP8) is a suitable model for the study of these midlife reproductive aging characteristics. Midlife SAMP8 mice aged 6.5-7.85 months (midlife SAMP8) exhibited shortened estrous cycles compared with SAMP8 mice aged 2-3 months (young SAMP8, P = .0040). Midlife SAMP8 mice had high FSH levels compared with young SAMP8 mice, and mice with a single day of high FSH exhibited statistically elevated FSH throughout the cycle, ranging from 1.8- to 3.6-fold elevation on the days of proestrus, estrus, metestrus, and diestrus (P < .05). Midlife SAMP8 mice displayed more variance in FSH than young SAMP8 mice (P = .01). Midlife SAMP8 ovulated fewer oocytes (P = .0155). SAMP8 oocytes stained with fluorescently labeled antitubulin antibodies and scored in fluorescence microscopy exhibited increased incidence of meiotic spindle aberrations with age, from 2/126 (1.59%) in young SAMP8 to 38/139 (27.3%) in midlife SAMP8 (17.2-fold increase, P < .0001). Finally, SAMP8 exhibited declining fertility from 8.9 pups/litter in young SAMP8 to 3.5 pups/litter in midlife SAMP8 mice (P < .0001). The age at which these changes occur is younger than for most mouse strains, and their simultaneous occurrence within a single strain has not been described previously. We propose that SAMP8 mice are a model of midlife human female reproductive aging.

  8. The effects of high energy electron beam irradiation in air on accelerated aging and on the structure property relationships of low density polyethylene

    NASA Astrophysics Data System (ADS)

    Murray, Kieran A.; Kennedy, James E.; McEvoy, Brian; Vrain, Olivier; Ryan, Damien; Cowman, Richard; Higginbotham, Clement L.

    2013-02-01

    The response of low density polyethylene (LDPE) to high energy electron beam irradiation in air (10 MeV) between 25 and 400 kGy was examined and compared to non-irradiated polyethylene in terms of the mechanical and structural properties. To quantify the degree of crosslinking, swelling studies were performed and from this it was observed that the crosslink density increased as the irradiation dose increased. Furthermore, a reduction was observed in the numerical data for molar mass between adjacent crosslinks and the number of monomeric units between adjacent crosslinks as the irradiation dose was conducted incrementally. Accelerated aging provided evidence that radicals became trapped in the polymer matrix of LDPE and this in turn initiated further reactions to transpire as time elapsed, leading to additional alteration in the structural properties. Fourier transform infrared spectroscopy (FTIR) was implemented to provide insight into this. This technique established that the aging process had increased the oxidative degradation products due to oxygen permeation into the polymer and double bonds within the material. Mechanical testing revealed an increase in the tensile strength and a decrease in the elongation at break. Accelerated aging caused additional modifications to occur in the mechanical properties which are further elucidated throughout this study. Dynamic frequency sweeps investigated the effects of irradiation on the structural properties of LDPE. The effect of varying the irradiation dose concentration was apparent as this controlled the level of crosslinking within the material. Maxwell and Kelvin or Voigt models were employed in this analytical technique to define the reaction procedure of the frequency sweep test with regards to non-crosslinked and crosslinked LDPE.

  9. The Influence of Passive Acceleration and Exercise+Acceleration on Work Capacity and Orthostasis

    NASA Technical Reports Server (NTRS)

    Simonson, S. R.; Cowell, S. A.; Stocks, J. M.; Biagini, H. W.; Vener, J. M.; Evetts, S. N.; Bailey, K. N.; Evans, J.; Knapp, C.; Greenleaf, J. E.

    1999-01-01

    The losses of aerobic power and orthostatic tolerance are significant effects of manned C) spaceflight that can negatively impact crew health and safety. Daily acceleration and aerobic training may ameliorate these effects. To determine the influence of passive intermittent +Gz acceleration (PA) training and active acceleration + interval exercise (AE) training on work 0 0 capacity and the acute (1 min) response to 70 deg head-up tilt, 6 men (X-Bar SD: age, 33 +/- 6 y; height, 178.3 +/- 4.6 cm; mass, 86.3 +/- 6.6 kg) participated in two 3-wk training protocols. It was hypothesized that PA and AE training would improve orthostatic tolerance and that the addition of aerobic conditioning, would not alter this effect.

  10. Health coaching and pedometers to enhance physical activity and prevent falls in community-dwelling people aged 60 years and over: study protocol for the Coaching for Healthy AGEing (CHAnGE) cluster randomised controlled trial

    PubMed Central

    Tiedemann, Anne; Rissel, Chris; Howard, Kirsten; Tong, Allison; Merom, Dafna; Smith, Stuart; Wickham, James; Bauman, Adrian; Lord, Stephen R; Vogler, Constance; Lindley, Richard I; Simpson, Judy M; Allman-Farinelli, Margaret; Sherrington, Catherine

    2016-01-01

    Introduction Prevention of falls and promotion of physical activity are essential for maximising well-being in older age. However, there is evidence that promoting physical activity among older people without providing fall prevention advice may increase fall rates. This trial aims to establish the impact of a physical activity and fall prevention programme compared with a healthy eating programme on physical activity and falls among people aged 60+ years. Methods and analysis This cluster randomised controlled trial will involve 60 groups of community-dwelling people aged 60+ years. Participating groups will be randomised to: (1) a physical activity and fall prevention intervention (30 groups), involving written information, fall risk assessment and prevention advice, a pedometer-based physical activity tracker and telephone-based health coaching; or (2) a healthy eating intervention (30 groups) involving written information and telephone-based dietary coaching. Primary outcomes will be objectively measured physical activity at 12 months post-randomisation and self-reported falls throughout the 12-month trial period. Secondary outcomes include: the proportion of fallers, the proportion of people meeting the Australian physical activity guidelines, body mass index, eating habits, mobility goal attainment, mobility-related confidence, quality of life, fear of falling, risk-taking behaviour, mood, well-being, self-reported physical activity, disability, and health and community service use. The between-group difference in the number of falls per person-year will be analysed using negative binomial regression models. For the continuously scored primary and secondary outcome measures, linear regression adjusted for corresponding baseline scores will assess the effect of group allocation. Analyses will be preplanned, conducted while masked to group allocation, will take into account cluster randomisation, and will use an intention-to-treat approach. Ethics and

  11. An assessment of anti-Müllerian hormone in predicting mating outcomes in female hamsters that have undergone natural and chemically-accelerated reproductive aging.

    PubMed

    Roosa, Kristen A; Zysling, Devin A; Place, Ned J

    2015-04-01

    In mammals, female fertility declines with age due in part to a progressive loss of ovarian follicles. The rate of follicle decline varies among individuals making it difficult to predict the age of onset of reproductive senescence. Serum anti-Müllerian hormone (AMH) concentrations correlate with the numbers of ovarian follicles, and therefore, AMH could be a useful predictor of female fertility. In women and some production animals, AMH is used to identify which individuals will respond best to ovarian stimulation for assisted reproductive technologies. However, few studies have evaluated AMH's predictive value in unassisted reproduction, and they have yielded conflicting results. To assess the predictive value of AMH in the context of reproductive aging, we prospectively measured serum AMH in 9-month-old Siberian hamsters shortly before breeding them. Female Siberian hamsters experience substantial declines in fertility and fecundity by 9months of age. We also measured serum AMH in 5-month-old females treated with 4-vinylcyclohexene diepoxide (VCD), which selectively destroys ovarian follicles and functionally accelerates ovarian aging. Vehicle-treated 5-month-old females served as controls. AMH concentrations were significantly reduced in VCD-treated females yet many females with low AMH reproduced successfully. On average, both young and old hamsters that littered had higher AMH concentrations than females that did not. However, some females with relatively high AMH concentrations failed to litter, whereas several with low AMH succeeded. Our results suggest that mean AMH concentration can predict mating outcomes on a population or group level, but on an individual basis, a single AMH determination is less informative.

  12. Dynamic mechanical and molecular weight measurements on polymer bonded explosives from thermally accelerated aging tests. II. A poly(ester-urethane) binder

    SciTech Connect

    Hoffman, D.M.; Caley, L.E.

    1981-01-01

    The molecular weight distribution and dynamic mechanical properties of an experimental polymer-bonded explosive, X-0282, maintained at 23, 60, and 74/sup 0/C for 3.75 y were examined, X-0282 is 95.5% 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclo-octane explosive and 4.5% Estane 5703, a segmented poly(ester-urethane). Two mechanical relaxations at about -24 and 42/sup 0/C were found in the X-0282 aged at room temperature for 3.75 years. A third relaxation at about 85/sup 0/C was found in X-0282 aged at 60 and 74/sup 0/C. The relaxation at -24/sup 0/C is associated with the soft segment glass transition of the binder. The relaxation at 42/sup 0/C is associated with the soft segment melting and may also contain a component due to the hard segment glass transition. The relaxation at 85/sup 0/C is probably associated with improved soft segment crystallite perfection. The molecular weight of the poly(ester-urethane) binder decreased significantly with increasing accelerated aging temperature. A simple random chain scission model of the urethane degradation kinetics in the presence of explosive yields an activation energy of 11.6 kcal/mole. This model predicts a use life of about 17.5 years under the worst military operating conditions (continuous operation at 74/sup 0/C).

  13. Linear Accelerators

    SciTech Connect

    Sidorin, Anatoly

    2010-01-05

    In linear accelerators the particles are accelerated by either electrostatic fields or oscillating Radio Frequency (RF) fields. Accordingly the linear accelerators are divided in three large groups: electrostatic, induction and RF accelerators. Overview of the different types of accelerators is given. Stability of longitudinal and transverse motion in the RF linear accelerators is briefly discussed. The methods of beam focusing in linacs are described.

  14. Environmental aging in polycrystalline-Si photovoltaic modules: comparison of chamber-based accelerated degradation studies with field-test data

    NASA Astrophysics Data System (ADS)

    Lai, T.; Biggie, R.; Brooks, A.; Potter, B. G.; Simmons-Potter, K.

    2015-09-01

    Lifecycle degradation testing of photovoltaic (PV) modules in accelerated-degradation chambers can enable the prediction both of PV performance lifetimes and of return-on-investment for installations of PV systems. With degradation results strongly dependent on chamber test parameters, the validity of such studies relative to fielded, installed PV systems must be determined. In the present work, accelerated aging of a 250 W polycrystalline silicon module is compared to real-time performance degradation in a similar polycrystalline-silicon, fielded, PV technology that has been operating since October 2013. Investigation of environmental aging effects are performed in a full-scale, industrial-standard environmental chamber equipped with single-sun irradiance capability providing illumination uniformity of 98% over a 2 x 1.6 m area. Time-dependent, photovoltaic performance (J-V) is evaluated over a recurring, compressed night-day cycle providing representative local daily solar insolation for the southwestern United States, followed by dark (night) cycling. This cycle is synchronized with thermal and humidity environmental variations that are designed to mimic, as closely as possible, test-yard conditions specific to a 12 month weather profile for a fielded system in Tucson, AZ. Results confirm the impact of environmental conditions on the module long-term performance. While the effects of temperature de-rating can be clearly seen in the data, removal of these effects enables the clear interpretation of module efficiency degradation with time and environmental exposure. With the temperature-dependent effect removed, the normalized efficiency is computed and compared to performance results from another panel of similar technology that has previously experienced identical climate changes in the test yard. Analysis of relative PV module efficiency degradation for the chamber-tested system shows good comparison to the field-tested system with ~2.5% degradation following

  15. Morphometric age estimate of the last phase of accelerated uplift in the Kazdag area (Biga Peninsula, NW Turkey)

    NASA Astrophysics Data System (ADS)

    Demoulin, A.; Altin, T. Bayer; Beckers, A.

    2013-11-01

    While the Plio-Quaternary uplift of the Kazdag mountain range (Biga Peninsula, NW Turkey) is generally acknowledged, little is known about its detailed timing. Partly because of this lack of data, the cause of this uplift phase is also debated, being associated either to back-arc extension in the rear of the Hellenic subduction zone, to transpression along the northern edge of the west-moving Anatolian microplate, or to extension driven by gravitational collapse. Here, we perform a morphometric study of the fluvial landscape at the scale of the Biga Peninsula, coupling the recently developed R/SR analysis of the drainage network with concavity and steepness measures of a set of 29 rivers of all sizes. While the dependence of profile concavity on basin size confirms that the landscape of the peninsula is still in a transient state, the spatial distribution of profile steepness values characterized by higher values for streams flowing down from the Kazdag massif shows that the latter undergoes higher uplift rates than the rest of the peninsula. We obtain a SR value of 0.324 ± 0.035 that, according to the relation established by Demoulin (2012), yields an age range of 0.5-1.3 Ma and a most probable value of 0.8 Ma for the time of the last tectonic perturbation in the region. In agreement with the analysis of knickpoint migration in a subset of rivers, this suggests that a pulse of uplift occurred at that time and, corroborated by sparse published observations in the Bayramiç and Çanakkale depressions, that the peninsula was uplifted as a whole from that time. This uplift pulse might have been caused by transient compressive conditions in the Anatolian plate when the Eratosthenes seamount came to subduct beneath the Cyprus arc around the early-to-mid Pleistocene transition (Schattner, 2010).

  16. Effect of gamma radiation and accelerated aging on the mechanical and thermal behavior of HDPE/HA nano-composites for bone tissue regeneration

    PubMed Central

    2013-01-01

    Background The replacement of hard tissues demands biocompatible and sometimes bioactive materials with properties similar to those of bone. Nano-composites made of biocompatible polymers and bioactive inorganic nano particles such as HDPE/HA have attracted attention as permanent bone substitutes due to their excellent mechanical properties and biocompatibility. Method The HDPE/HA nano-composite is prepared using melt blending at different HA loading ratios. For evaluation of the degradation by radiation, gamma rays of 35 kGy, and 70 kGy were used to irradiate the samples at room temperature in vacuum. The effects of accelerated ageing after gamma irradiation on morphological, mechanical and thermal properties of HDPE/HA nano-composites were measured. Results In Vitro test results showed that the HDPE and all HDPE/HA nano-composites do not exhibit any cytotoxicity to WISH cell line. The results also indicated that the tensile properties of HDPE/HA nano-composite increased with increasing the HA content except fracture strain decreased. The dynamic mechanical analysis (DMA) results showed that the storage and loss moduli increased with increasing the HA ratio and the testing frequency. Finally, it is remarked that all properties of HDPE/HA is dependent on the irradiation dose and accelerated aging. Conclusion Based on the experimental results, it is found that the addition of 10%, 20% and 30% HA increases the HDPE stiffness by 23%, 44 and 59% respectively. At the same time, the G’ increased from 2.25E11 MPa for neat HDPE to 4.7E11 MPa when 30% HA was added to the polymer matrix. Also, significant improvements in these properties have been observed due to irradiation. Finally, the overall properties of HDPE and its nano-composite properties significantly decreased due to aging and should be taken into consideration in the design of bone substitutes. It is attributed that the developed HDPE/HA nano-composites could be a good alternative material for bone tissue

  17. Can Accelerators Accelerate Learning?

    NASA Astrophysics Data System (ADS)

    Santos, A. C. F.; Fonseca, P.; Coelho, L. F. S.

    2009-03-01

    The 'Young Talented' education program developed by the Brazilian State Funding Agency (FAPERJ) [1] makes it possible for high-schools students from public high schools to perform activities in scientific laboratories. In the Atomic and Molecular Physics Laboratory at Federal University of Rio de Janeiro (UFRJ), the students are confronted with modern research tools like the 1.7 MV ion accelerator. Being a user-friendly machine, the accelerator is easily manageable by the students, who can perform simple hands-on activities, stimulating interest in physics, and getting the students close to modern laboratory techniques.

  18. Can Accelerators Accelerate Learning?

    SciTech Connect

    Santos, A. C. F.; Fonseca, P.; Coelho, L. F. S.

    2009-03-10

    The 'Young Talented' education program developed by the Brazilian State Funding Agency (FAPERJ)[1] makes it possible for high-schools students from public high schools to perform activities in scientific laboratories. In the Atomic and Molecular Physics Laboratory at Federal University of Rio de Janeiro (UFRJ), the students are confronted with modern research tools like the 1.7 MV ion accelerator. Being a user-friendly machine, the accelerator is easily manageable by the students, who can perform simple hands-on activities, stimulating interest in physics, and getting the students close to modern laboratory techniques.

  19. Supplementation with Lactobacillus plantarum WCFS1 Prevents Decline of Mucus Barrier in Colon of Accelerated Aging Ercc1−/Δ7 Mice

    PubMed Central

    van Beek, Adriaan A.; Sovran, Bruno; Hugenholtz, Floor; Meijer, Ben; Hoogerland, Joanne A.; Mihailova, Violeta; van der Ploeg, Corine; Belzer, Clara; Boekschoten, Mark V.; Hoeijmakers, Jan H. J.; Vermeij, Wilbert P.; de Vos, Paul; Wells, Jerry M.; Leenen, Pieter J. M.; Nicoletti, Claudio; Hendriks, Rudi W.; Savelkoul, Huub F. J.

    2016-01-01

    Although it is clear that probiotics improve intestinal barrier function, little is known about the effects of probiotics on the aging intestine. We investigated effects of 10-week bacterial supplementation of Lactobacillus plantarum WCFS1, Lactobacillus casei BL23, or Bifidobacterium breve DSM20213 on gut barrier and immunity in 16-week-old accelerated aging Ercc1−/Δ7 mice, which have a median lifespan of ~20 weeks, and their wild-type littermates. The colonic barrier in Ercc1−/Δ7 mice was characterized by a thin (< 10 μm) mucus layer. L. plantarum prevented this decline in mucus integrity in Ercc1−/Δ7 mice, whereas B. breve exacerbated it. Bacterial supplementations affected the expression of immune-related genes, including Toll-like receptor 4. Regulatory T cell frequencies were increased in the mesenteric lymph nodes of L. plantarum- and L. casei-treated Ercc1−/Δ7 mice. L. plantarum- and L. casei-treated Ercc1−/Δ7 mice showed increased specific antibody production in a T cell-dependent immune response in vivo. By contrast, the effects of bacterial supplementation on wild-type control mice were negligible. Thus, supplementation with L. plantarum – but not with L. casei and B. breve – prevented the decline in the mucus barrier in Ercc1−/Δ7 mice. Our data indicate that age is an important factor influencing beneficial or detrimental effects of candidate probiotics. These findings also highlight the need for caution in translating beneficial effects of probiotics observed in young animals or humans to the elderly. PMID:27774093

  20. Rational Protocols

    NASA Astrophysics Data System (ADS)

    Cachin, Christian

    Security research continues to provide a plethora of new protocols and mechanisms; these solutions patch either existing vulnerabilities found in practical systems or solve hypothetical security problems in the sense that the problem is often conceived at the same time when the first solution is proposed. Yet only a very small fraction of this research is relevant to ordinary users in the sense that they are willing to actually deploy the technology.

  1. Age-related expression of sigma1 receptors and antidepressant efficacy of a selective agonist in the senescence-accelerated (SAM) mouse.

    PubMed

    Phan, Vân-Ly; Miyamoto, Yoshiaki; Nabeshima, Toshitaka; Maurice, Tangui

    2005-02-15

    The sigma1 receptor is a unique intracellular receptor whose activation results in an efficient modulation of several neurotransmitter responses. Its role as a target for the rapid nongenomic effects of neuro(active)steroids and the age-related diminutions in steroid levels suggested that targeting the sigma1 receptor might allow alleviation of age-related neuronal dysfunctions. We examined here the expression and behavioral efficacy of sigma1 receptors in the senescence-accelerated (SAM) mouse model. The sigma1 receptor mRNA expression was measured by using comparative RT-PCR in the olfactory bulb, hippocampus, hypothalamus, cortex, or cerebellum of senescence-prone SAMP/8 and senescence-resistant SAMR/1 control animals. No difference was observed between substrains in 6-, 9-, and 12-month-old (m.o.) mice. The sigma1 protein expression was analyzed by using immunohistochemical techniques. Labeling was intense in the olfactory bulb, hippocampus, hypothalamus, and midbrain of both SAMR/1 and SAMP/8 mice, and the distribution appeared unchanged in 6-, 9-, and 12-m.o. animals. The receptor's in vivo availability was examined by using in vivo [3H](+)-SKF-10,047 binding. No age-related difference was observed in the olfactory bulb, hippocampus, hypothalamus, cortex, cerebellum, and brainstem of 6- or 12-m.o. SAMR/1 or SAMP/8 mice. The antidepressant efficacy of the selective agonist igmesine was examined in the forced-swimming test. The compound decreased significantly the immobility duration at 60 mg/kg in 6- and 12-m.o. SAMR/1 and in 6-m.o. SAMP/8 mice. In 12-m.o. SAMP/8 mice, the drug efficacy was facilitated; a significant effect was measured at 30 mg/kg. Decreased neurosteroid levels, particularly of progesterone, were seen in 12-m.o. SAMP/8 mice that might explain the enhanced efficacy of igmesine. Preserved sigma1 receptor expression and enhanced behavioral efficacy of sigma1 agonists were measured in SAM animals, confirming the therapeutic opportunities for

  2. Confronting Twin Paradox Acceleration

    NASA Astrophysics Data System (ADS)

    Murphy, Thomas W.

    2016-05-01

    The resolution to the classic twin paradox in special relativity rests on the asymmetry of acceleration. Yet most students are not exposed to a satisfactory analysis of what exactly happens during the acceleration phase that results in the nonaccelerated observer's more rapid aging. The simple treatment presented here offers both graphical and quantitative solutions to the problem, leading to the correct result that the acceleration-induced age gap is 2Lβ years when the one-way distance L is expressed in light-years and velocity β ≡v/c .

  3. The senescence-accelerated prone mouse (SAMP8): a model of age-related cognitive decline with relevance to alterations of the gene expression and protein abnormalities in Alzheimer's disease.

    PubMed

    Butterfield, D Allan; Poon, H Fai

    2005-10-01

    The senescence-accelerated mouse (SAM) is an accelerated aging model that was established through phenotypic selection from a common genetic pool of AKR/J strain of mice. The SAM model was established in 1981, including nine major senescence-accelerated mouse prone (SAMP) substrains and three major senescence-accelerated mouse resistant (SAMR) substrains, each of which exhibits characteristic disorders. Recently, SAMP8 have drawn attention in gerontological research due to its characteristic learning and memory deficits at old age. Many recent reports provide insight into mechanisms of the cognitive impairment and pathological changes in SAMP8. Therefore, this mini review examines the recent findings of SAMP8 mice abnormalities at the gene and protein levels. The genes and proteins described in this review are functionally categorized into neuroprotection, signal transduction, protein folding/degradation, cytoskeleton/transport, immune response and reactive oxygen species (ROS) production. All of these processes are involved in learning and memory. Although these studies provide insight into the mechanisms that contribute to the learning and memory decline in aged SAMP8 mice, higher throughput techniques of proteomics and genomics are necessary to study the alterations of gene expression and protein abnormalities in SAMP8 mice brain in order to more completely understand the central nervous system dysfunction in this mouse model. The SAMP8 is a good animal model to investigate the fundamental mechanisms of age-related learning and memory deficits at the gene and protein levels. PMID:16026957

  4. Interfacing to accelerator instrumentation

    SciTech Connect

    Shea, T.J.

    1995-12-31

    As the sensory system for an accelerator, the beam instrumentation provides a tremendous amount of diagnostic information. Access to this information can vary from periodic spot checks by operators to high bandwidth data acquisition during studies. In this paper, example applications will illustrate the requirements on interfaces between the control system and the instrumentation hardware. A survey of the major accelerator facilities will identify the most popular interface standards. The impact of developments such as isochronous protocols and embedded digital signal processing will also be discussed.

  5. Network acceleration techniques

    NASA Technical Reports Server (NTRS)

    Crowley, Patricia (Inventor); Awrach, James Michael (Inventor); Maccabe, Arthur Barney (Inventor)

    2012-01-01

    Splintered offloading techniques with receive batch processing are described for network acceleration. Such techniques offload specific functionality to a NIC while maintaining the bulk of the protocol processing in the host operating system ("OS"). The resulting protocol implementation allows the application to bypass the protocol processing of the received data. Such can be accomplished this by moving data from the NIC directly to the application through direct memory access ("DMA") and batch processing the receive headers in the host OS when the host OS is interrupted to perform other work. Batch processing receive headers allows the data path to be separated from the control path. Unlike operating system bypass, however, the operating system still fully manages the network resource and has relevant feedback about traffic and flows. Embodiments of the present disclosure can therefore address the challenges of networks with extreme bandwidth delay products (BWDP).

  6. Antisense directed against PS-1 gene decreases brain oxidative markers in aged senescence accelerated mice (SAMP8) and reverses learning and memory impairment: a proteomics study.

    PubMed

    Fiorini, Ada; Sultana, Rukhsana; Förster, Sarah; Perluigi, Marzia; Cenini, Giovanna; Cini, Chiara; Cai, Jian; Klein, Jon B; Farr, Susan A; Niehoff, Michael L; Morley, John E; Kumar, Vijaya B; Allan Butterfield, D

    2013-12-01

    Amyloid β-peptide (Aβ) plays a central role in the pathophysiology of Alzheimer's disease (AD) through the induction of oxidative stress. This peptide is produced by proteolytic cleavage of amyloid precursor protein (APP) by the action of β- and γ-secretases. Previous studies demonstrated that reduction of Aβ, using an antisense oligonucleotide (AO) directed against the Aβ region of APP, reduced oxidative stress-mediated damage and prevented or reverted cognitive deficits in senescence-accelerated prone mice (SAMP8), a useful animal model for investigating the events related to Aβ pathology and possibly to the early phase of AD. In the current study, aged SAMP8 were treated by AO directed against PS-1, a component of the γ-secretase complex, and tested for learning and memory in T-maze foot shock avoidance and novel object recognition. Brain tissue was collected to identify the decrease of oxidative stress and to evaluate the proteins that are differently expressed and oxidized after the reduction in free radical levels induced by Aβ. We used both expression proteomics and redox proteomics approaches. In brain of AO-treated mice a decrease of oxidative stress markers was found, and the proteins identified by proteomics as expressed differently or nitrated are involved in processes known to be impaired in AD. Our results suggest that the treatment with AO directed against PS-1 in old SAMP8 mice reverses learning and memory deficits and reduces Aβ-mediated oxidative stress with restoration to the normal condition and identifies possible pharmacological targets to combat this devastating dementing disease.

  7. Using an eHealth Intervention to Stimulate Health Behavior for the Prevention of Cognitive Decline in Dutch Adults: A Study Protocol for the Brain Aging Monitor

    PubMed Central

    2015-01-01

    Background Internet-delivered intervention programs are an effective way of changing health behavior in an aging population. The same population has an increasing number of people with cognitive decline or cognitive impairments. Modifiable lifestyle risk factors such as physical activity, nutrition, smoking, alcohol consumption, sleep, and stress all influence the probability of developing neurodegenerative diseases such as Alzheimer’s disease. Objective This study aims to answer two questions: (1) Is the use of a self-motivated, complex eHealth intervention effective in changing multiple health behaviors related to cognitive aging in Dutch adults in the work force, especially those aged 40 and over? and (2) Does this health behavior change result in healthier cognitive aging patterns and contribute to preventing or delaying future onset of neurodegenerative syndromes? Methods The Brain Aging Monitor study uses a quasi-experimental 2-year pre-posttest design. The Brain Aging Monitor is an online, self-motivated lifestyle intervention program. Recruitment is done both in medium to large organizations and in the Dutch general population over the age of 40. The main outcome measure is the relationship between lifestyle change and cognitive aging. The program uses different strategies and modalities such as Web content, email, online newsletters, and online games to aid its users in behavior change. To build self-regulatory skills, the Brain Aging Monitor offers its users goal-setting activities, skill-building activities, and self-monitoring. Results Study results are expected to be published in early 2016. Conclusions This study will add to the body of evidence on the effectiveness of eHealth intervention programs with the combined use of state-of-the-art applied games and established behavior change techniques. This will lead to new insights on how to use behavior change techniques and theory in multidimensional lifestyle eHealth research, and how these techniques

  8. Application of local area networks to accelerator control systems at the Stanford Linear Accelerator

    SciTech Connect

    Fox, J.D.; Linstadt, E.; Melen, R.

    1983-03-01

    The history and current status of SLAC's SDLC networks for distributed accelerator control systems are discussed. These local area networks have been used for instrumentation and control of the linear accelerator. Network topologies, protocols, physical links, and logical interconnections are discussed for specific applications in distributed data acquisition and control system, computer networks and accelerator operations.

  9. Future accelerators (?)

    SciTech Connect

    John Womersley

    2003-08-21

    I describe the future accelerator facilities that are currently foreseen for electroweak scale physics, neutrino physics, and nuclear structure. I will explore the physics justification for these machines, and suggest how the case for future accelerators can be made.

  10. The impact of insecticide-treated school uniforms on dengue infections in school-aged children: study protocol for a randomised controlled trial in Thailand

    PubMed Central

    2012-01-01

    Background There is an urgent need to protect children against dengue since this age group is particularly sensitive to the disease. Since dengue vectors are active mainly during the day, a potential target for control should be schools where children spend a considerable amount of their day. School uniforms are the cultural norm in most developing countries, worn throughout the day. We hypothesise that insecticide-treated school uniforms will reduce the incidence of dengue infection in school-aged children. Our objective is to determine the impact of impregnated school uniforms on dengue incidence. Methods A randomised controlled trial will be conducted in eastern Thailand in a group of schools with approximately 2,000 students aged 7–18 years. Pre-fabricated school uniforms will be commercially treated to ensure consistent, high-quality insecticide impregnation with permethrin. A double-blind, randomised, crossover trial at the school level will cover two dengue transmission seasons. Discussion Practical issues and plans concerning intervention implementation, evaluation, analysing and interpreting the data, and possible policy implications arising from the trial are discussed. Trial registration clinicaltrial.gov. Registration number: NCT01563640 PMID:23153360

  11. Supervision of care networks for frail community dwelling adults aged 75 years and older: protocol of a mixed methods study

    PubMed Central

    Verver, Didi; Merten, Hanneke; Robben, Paul; Wagner, Cordula

    2015-01-01

    Introduction The Dutch healthcare inspectorate (IGZ) supervises the quality and safety of healthcare in the Netherlands. Owing to the growing population of (community dwelling) older adults and changes in the Dutch healthcare system, the IGZ is exploring new methods to effectively supervise care networks that exist around frail older adults. The composition of these networks, where formal and informal care takes place, and the lack of guidelines and quality and risk indicators make supervision complicated in the current situation. Methods and analysis This study consists of four phases. The first phase identifies risks for community dwelling frail older adults in the existing literature. In the second phase, a qualitative pilot study will be conducted to assess the needs and wishes of the frail older adults concerning care and well-being, perception of risks, and the composition of their networks, collaboration and coordination between care providers involved in the network. In the third phase, questionnaires based on the results of phase II will be sent to a larger group of frail older adults (n=200) and their care providers. The results will describe the composition of their care networks and prioritise risks concerning community dwelling older adults. Also, it will provide input for the development of a new supervision framework by the IGZ. During phase IV, a second questionnaire will be sent to the participants of phase III to establish changes of perception in risks and possible changes in the care networks. The framework will be tested by the IGZ in pilots, and the researchers will evaluate these pilots and provide feedback to the IGZ. Ethics and dissemination The study protocol was approved by the Scientific Committee of the EMGO+institute and the Medical Ethical review committee of the VU University Medical Centre. Results will be presented in scientific articles and reports and at meetings. PMID:26307619

  12. Investigation of alcohol-related social norms among youth aged 14–17 years in Perth, Western Australia: protocol for a respondent-driven sampling study

    PubMed Central

    Hildebrand, Janina; Maycock, Bruce; Howat, Peter; Burns, Sharyn; Allsop, Steve; Dhaliwal, Satvinder; Lobo, Roanna

    2013-01-01

    Introduction Alcohol use among young people is a major public health concern in Australia and internationally. Research elucidating social norms influencing alcohol use supports the desire to conform to peers. However, there is a lack of evidence on how social norms are transmitted from the community to young people and between family members and peers, as previous studies are limited to mainly school and university environments. This article describes the proposed process to investigate common alcohol-related norms held by 14-year-olds to 17-year-olds in Perth, Western Australia, and to clarify the process and pathways through which proalcohol norms are transmitted to adolescents. Methods and analysis This cross-sectional quantitative study will use respondent-driven sampling (RDS) to recruit a sample of 672 adolescents from sporting groups, youth programmes and the community in Perth. Data will be collected with a previously developed and validated multidimensional online survey instrument. A variety of strategies will be explored to aid participation including face-to-face recruitment and survey administration, web-based RDS and a ‘mature minor’ consent assessment protocol. Data analysis will include descriptive statistics of demographic characteristics, as well as social network and dyadic analyses, to explore the connections between shared understanding of norms and behaviours among individuals and how these translate into reported practices. Ethics and dissemination This research is expected to extend our understanding of normative development pathways to inform future interventions, and will be widely disseminated through conference presentations, peer-reviewed papers, media channels and community seminars. A study reference group of key health industry stakeholders will be established to encourage integration of study findings into policy and practice, and results will guide the development of community interventions. The Curtin University Human

  13. New practical treadmill protocol for clinical use.

    PubMed

    Wolthuis, R A; Froelicher, V F; Fischer, J; Noguera, I; Davis, G; Stewart, A J; Triebwasser, J H

    1977-05-01

    A new continuous treadmill protocol (USAFSAM) has been designed using a constant treadmill speed (3.3 miles/hour) and regular equal increments in treadmill grade (5%/3min). The constant treadmill speed requires only initial adaptation in patient stride, reduces technician adjustments and produces less electrocardiographic motion artifact than do protocols using multiple or higher treadmill speeds, or both. The regular equal increments in treadmill grade are easy to implement and provide a larger number of work loads than do protocols that are discontinuous or require larger changes in work load. The USAFSAM protocol was compared with the older Balke-Ware protocol in 26 healthy men (aged 30 to 59 years). Each fasting subject completed two maximal treadmill tests from each protocol. Measurements included minute heart rate from the electrocardiogram, auscultatory blood pressures and oxygen consumption obtained with standard techniques. Similarities in between-protocol measurements for submaximal and maximal treadmill efforts were impressive; differences were small and unimportant. Further, both protocols showed equal reproducibility for the measurements noted. Importantly, time to maximal effort was reduced by 24% with the USAFSAM protocol. The USAFSAM treadmill protocol has since been used in more than 500 clinical and screening examinations, thus confirming its advantages and practicality for routine clinical stress testing. Normal reference values previously established for the Balke-Ware protocol are shown to apply to the new USAFSAM protocol as well. PMID:857630

  14. Experimental design and analysis for accelerated degradation tests with Li-ion cells.

    SciTech Connect

    Doughty, Daniel Harvey; Thomas, Edward Victor; Jungst, Rudolph George; Roth, Emanuel Peter

    2003-08-01

    This document describes a general protocol (involving both experimental and data analytic aspects) that is designed to be a roadmap for rapidly obtaining a useful assessment of the average lifetime (at some specified use conditions) that might be expected from cells of a particular design. The proposed experimental protocol involves a series of accelerated degradation experiments. Through the acquisition of degradation data over time specified by the experimental protocol, an unambiguous assessment of the effects of accelerating factors (e.g., temperature and state of charge) on various measures of the health of a cell (e.g., power fade and capacity fade) will result. In order to assess cell lifetime, it is necessary to develop a model that accurately predicts degradation over a range of the experimental factors. In general, it is difficult to specify an appropriate model form without some preliminary analysis of the data. Nevertheless, assuming that the aging phenomenon relates to a chemical reaction with simple first-order rate kinetics, a data analysis protocol is also provided to construct a useful model that relates performance degradation to the levels of the accelerating factors. This model can then be used to make an accurate assessment of the average cell lifetime. The proposed experimental and data analysis protocols are illustrated with a case study involving the effects of accelerated aging on the power output from Gen-2 cells. For this case study, inadequacies of the simple first-order kinetics model were observed. However, a more complex model allowing for the effects of two concurrent mechanisms provided an accurate representation of the experimental data.

  15. Multipass Steering Protocols at Jefferson Lab

    SciTech Connect

    Ryan Bodenstein; Michael Tiefenback

    2007-06-22

    The CEBAF recirculating accelerator consists of two CW superconducting RF linacs, through which an electron beam is accelerated for up to 5 passes. Focusing and steering elements affect each pass differently, requiring a multipass steering protocol to correct the orbits. Perturbations include lens misalignments (including long-term ground motion), BPM offsets, and focusing and steering from RF fields inside the cavities. A previous treatment of this problem assumed all perturbations were localized at the quadrupoles and the absence of x-y coupling. Having analyzed the problem and characterized the solutions, we developed an empirical iterative protocol to compare against previous results in the presence of skew fields and cross-plane coupling. We plan to characterize static and acceleration-dependent components of the beam line perturbations to allow systematic and rapid configuration of the accelerator at different linac energy gains.

  16. A health economic model for the development and evaluation of innovations in aged care: an application to consumer-directed care—study protocol

    PubMed Central

    Ratcliffe, Julie; Lancsar, Emily; Luszcz, Mary; Crotty, Maria; Gray, Len; Paterson, Jan; Cameron, Ian D

    2014-01-01

    Introduction Consumer-directed care is currently being embraced within Australia and internationally as a means of promoting autonomy and choice in the delivery of health and aged care services. Despite its wide proliferation little research has been conducted to date to assess the views and preferences of older people for consumer-directed care or to assess the costs and benefits of such an approach relative to existing models of service delivery. Methods and analysis A comprehensive health economic model will be developed and applied to the evolution, implementation and evaluation of consumer-directed care in an Australian community aged care setting. A mixed methods approach comprising qualitative interviews and a discrete choice experiment will determine the attitudes and preferences of older people and their informal carers for consumer-directed care. The results of the qualitative interviews and the discrete choice experiment will inform the introduction of a new consumer-directed care innovation in service delivery. The cost-effectiveness of consumer-directed care will be evaluated by comparing incremental changes in resource use, costs and health and quality of life outcomes relative to traditional services. The discrete choice experiment will be repeated at the end of the implementation period to determine the extent to which attitudes and preferences change as a consequence of experience of consumer-directed care. The proposed framework will have wide applicability in the future development and economic evaluation of new innovations across the health and aged care sectors. Ethics and dissemination The study is approved by Flinders University Social and Behavioural Research Ethics Committee (Project No. 6114/SBREC). Findings from the qualitative interviews, discrete choice experiments and the economic evaluation will be reported at a workshop of stakeholders to be held in 2015 and will be documented in reports and in peer reviewed journal articles. PMID

  17. PAHA study: Psychological Active and Healthy Aging: psychological wellbeing, proactive attitude and happiness effects of whole-body vibration versus Multicomponent Training in aged women: study protocol for a randomized controlled trial

    PubMed Central

    2014-01-01

    Background Evidence demonstrates that physical exercise and psychological wellbeing are closely interlinked, particularly in older-aged women. However, research investigating how different forms of exercise influence mental health in older-aged women is underdeveloped. Methods/Design A randomized controlled trial (N = 300) will assess the relative effectiveness of two different exercise programs (whole-body vibration and Multicomponent Training) for improving psychological wellbeing in older-aged women. The following outcomes will be assessed at three time points (that is, pre, post, and follow-up): psychological wellbeing, proactive attitude, quality of life, and happiness. Discussion Results will have important implications for preventing psychological and physiological disease in older-aged women and for managing health-related costs for this population group. Trial registration Number NCT01966562 on Clinical Gov database the 8 October 2013 PMID:24886107

  18. Health-promoting behaviors and social support of women of reproductive age, and strategies for advancing their health: Protocol for a mixed methods study

    PubMed Central

    2011-01-01

    Background Determining the health-promoting behaviors of women during the important period of reproduction provides valuable information for designing appropriate intervention programs for advancing women's health. There is no study on the health-promoting behaviors of women of reproductive age in Iran. Thus, the aim of this study is to explore these health-promoting behaviors for the purpose of developing comprehensive and culturally sensitive health advancement strategies for Iranian women. Methods/Design This study has a sequential explanatory mixed methods design. The follow-up explanation model is used to elaborate the quantitative results by collecting qualitative data from participants who could best assist in elucidating the results. The study is conducted in two sequential phases. The first phase is a population-based cross-sectional survey in which 1350 Iranian women of reproductive age are selected by proportional random multistage cluster sampling of the 22 main municipal sectors of Tehran, Iran. Questionnaires are completed through a face-to-face interview. The second phase is a qualitative study in which participants are selected using purposive sampling in the form of extreme case sampling on the basis of health-promoting behavior scores. The qualitative phase is based on data collected from focus group discussions or individual in-depth interviews. A conventional qualitative content analysis approach is used, and the data are managed with a computer-assisted program. Women's health-promoting strategies are developed using the qualitative and quantitative results, a review of the related literature, and the nominal group technique among experts. Discussion The findings of this mixed methods sequential explanatory study, obtained using a culturally sensitive approach, provide insights into the health behavioral factors that need to be considered if preventive strategies and intervention programs are to be designed to promote women's health in the

  19. Use of senescence-accelerated mouse model in bleomycin-induced lung injury suggests that bone marrow-derived cells can alter the outcome of lung injury in aged mice.

    PubMed

    Xu, Jianguo; Gonzalez, Edilson T; Iyer, Smita S; Mac, Valerie; Mora, Ana L; Sutliff, Roy L; Reed, Alana; Brigham, Kenneth L; Kelly, Patricia; Rojas, Mauricio

    2009-07-01

    The incidence of pulmonary fibrosis increases with age. Studies from our group have implicated circulating progenitor cells, termed fibrocytes, in lung fibrosis. In this study, we investigate whether the preceding determinants of inflammation and fibrosis were augmented with aging. We compared responses to intratracheal bleomycin in senescence-accelerated prone mice (SAMP), with responses in age-matched control senescence-accelerated resistant mice (SAMR). SAMP mice demonstrated an exaggerated inflammatory response as evidenced by lung histology. Bleomycin-induced fibrosis was significantly higher in SAMP mice compared with SAMR controls. Consistent with fibrotic changes in the lung, SAMP mice expressed higher levels of transforming growth factor-beta1 in the lung. Furthermore, SAMP mice showed higher numbers of fibrocytes and higher levels of stromal cell-derived factor-1 in the peripheral blood. This study provides the novel observation that apart from increases in inflammatory and fibrotic factors in response to injury, the increased mobilization of fibrocytes may be involved in age-related susceptibility to lung fibrosis. PMID:19359440

  20. Accelerating the translation of research into practice in long term services and supports: a critical need for federal infrastructure at the nexus of aging and disability.

    PubMed

    Washko, Michelle M; Campbell, Margaret; Tilly, Jane

    2012-01-01

    The nexus of aging and disability, characterized by the phenomenon of aging with a disability, will become more visible as the population ages and the number of people with disabilities surviving to midlife increases. This article addresses 3 interrelated issues critical to the fields of aging and disability: increasing demand for community-based long-term services and supports, a paucity of evidence-based programs demonstrating effectiveness in facilitating independence for those aging with a disability, and lack of a federal infrastructure to support coordinated investments in research-to-practice for this population. Suggestions for federal interagency collaborations are given, along with roles for key stakeholders.

  1. 21 CFR 58.120 - Protocol.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ..., body weight range, sex, source of supply, species, strain, substrain, and age of the test system. (5... methods to be used. (b) All changes in or revisions of an approved protocol and the reasons...

  2. Can social dancing prevent falls in older adults? a protocol of the Dance, Aging, Cognition, Economics (DAnCE) fall prevention randomised controlled trial

    PubMed Central

    2013-01-01

    Background Falls are one of the most common health problems among older people and pose a major economic burden on health care systems. Exercise is an accepted stand-alone fall prevention strategy particularly if it is balance training or regular participation in Tai chi. Dance shares the ‘holistic’ approach of practices such as Tai chi. It is a complex sensorimotor rhythmic activity integrating multiple physical, cognitive and social elements. Small-scale randomised controlled trials have indicated that diverse dance styles can improve measures of balance and mobility in older people, but none of these studies has examined the effect of dance on falls or cognition. This study aims to determine whether participation in social dancing: i) reduces the number of falls; and ii) improves cognitive functions associated with fall risk in older people. Methods/design A single-blind, cluster randomised controlled trial of 12 months duration will be conducted. Approximately 450 participants will be recruited from 24 self-care retirement villages that house at least 60 residents each in Sydney, Australia. Village residents without cognitive impairment and obtain medical clearance will be eligible. After comprehensive baseline measurements including physiological and cognitive tests and self-completed questionnaires, villages will be randomised to intervention sites (ballroom or folk dance) or to a wait-listed control using a computer randomisation method that minimises imbalances between villages based on two baseline fall risk measures. Main outcome measures are falls, prospectively measured, and the Trail Making cognitive function test. Cost-effectiveness and cost-utility analyses will be performed. Discussion This study offers a novel approach to balance training for older people. As a community-based approach to fall prevention, dance offers older people an opportunity for greater social engagement, thereby making a major contribution to healthy ageing. Providing

  3. Efficacy of baby-CIMT: study protocol for a randomised controlled trial on infants below age 12 months, with clinical signs of unilateral CP

    PubMed Central

    2014-01-01

    Background Infants with unilateral brain lesions are at high risk of developing unilateral cerebral palsy (CP). Given the great plasticity of the young brain, possible interventions for infants at risk of unilateral CP deserve exploration. Constraint-induced movement therapy (CIMT) is known to be effective for older children with unilateral CP but is not systematically used for infants. The development of CIMT for infants (baby-CIMT) is described here, as is the methodology of an RCT comparing the effects on manual ability development of baby-CIMT versus baby-massage. The main hypothesis is that infants receiving baby-CIMT will develop manual ability in the involved hand faster than will infants receiving baby-massage in the first year of life. Method and design The study will be a randomised, controlled, prospective parallel-group trial. Invited infants will be to be randomised to either the baby-CIMT or the baby-massage group if they: 1) are at risk of developing unilateral CP due to a known neonatal event affecting the brain or 2) have been referred to Astrid Lindgren Children’s Hospital due to asymmetric hand function. The inclusion criteria are age 3–8 months and established asymmetric hand use. Infants in both groups will receive two 6-weeks training periods separated by a 6-week pause, for 12 weeks in total of treatment. The primary outcome measure will be the new Hand Assessment for Infants (HAI) for evaluating manual ability. In addition, the Parenting Sense of Competence scale and Alberta Infant Motor Scale will be used. Clinical neuroimaging will be utilized to characterise the brain lesion type. To compare outcomes between treatment groups generalised linear models will be used. Discussion The model of early intensive intervention for hand function, baby-CIMT evaluated by the Hand Assessment for Infants (HAI) will have the potential to significantly increase our understanding of how early intervention of upper limb function in infants at risk of

  4. The Chinese traditional medicine 'Bushen Yinao Pian' increased the level of ageing-related gene LRPAP-1 expression in the cerebral tissue of accelerated senescence-prone mouse 8/Ta.

    PubMed

    Zhang, Chong; Yang, Ting; Wang, Jingang; Liu, Guisheng; Chen, Qingxuan

    2005-04-01

    The molecular mechanism of the Chinese traditional medicine 'Bushen Yinao Pian' (a complex prescription used for clinical anti-ageing in China for over 20 years) is elusive. In this study, the cDNA of low-density lipoprotein related-receptor associated protein-1 (LRPAP-1), an ageing-related gene, which functions as a chaperon or escort protein in the intracellular transport of low-density lipoprotein related-receptor, a transporter of amyloid beta protein (AbetaP), had been cloned by screening cDNA library based on analyzing the gene expression in cerebral tissue between the test and the control accelerated senescence-prone mouse 8/Ta (SAMP8/Ta). The result shows that this complex prescription increased the expression level of LRPAP-1. It indicated that the Chinese traditional medicine 'Bushen Yinao Pian' plays an important role in anti-ageing by increasing LRPAP-1 expression level. PMID:15763364

  5. Radioisotope Dating with Accelerators.

    ERIC Educational Resources Information Center

    Muller, Richard A.

    1979-01-01

    Explains a new method of detecting radioactive isotopes by counting their accelerated ions rather than the atoms that decay during the counting period. This method increases the sensitivity by several orders of magnitude, and allows one to find the ages of much older and smaller samples. (GA)

  6. Wakefield accelerators

    SciTech Connect

    Simpson, J.D.

    1990-01-01

    The search for new methods to accelerate particle beams to high energy using high gradients has resulted in a number of candidate schemes. One of these, wakefield acceleration, has been the subject of considerable R D in recent years. This effort has resulted in successful proof of principle experiments and in increased understanding of many of the practical aspects of the technique. Some wakefield basics plus the status of existing and proposed experimental work is discussed, along with speculations on the future of wake field acceleration. 10 refs., 6 figs.

  7. LINEAR ACCELERATOR

    DOEpatents

    Colgate, S.A.

    1958-05-27

    An improvement is presented in linear accelerators for charged particles with respect to the stable focusing of the particle beam. The improvement consists of providing a radial electric field transverse to the accelerating electric fields and angularly introducing the beam of particles in the field. The results of the foregoing is to achieve a beam which spirals about the axis of the acceleration path. The combination of the electric fields and angular motion of the particles cooperate to provide a stable and focused particle beam.

  8. Carotid Intima-Media Thickness at Age 30, Birth Weight, Accelerated Growth during Infancy and Breastfeeding: A Birth Cohort Study in Southern Brazil

    PubMed Central

    Linhares, Rogério da Silva; Gigante, Denise Petrucci; de Barros, Fernando Celso Lopes Fernandes; Horta, Bernardo Lessa

    2015-01-01

    Objective To examine the relationship between carotid intima-media thickness (IMT) at age 30 and birth characteristics, growth during infancy, and breastfeeding duration, among subjects who have been prospectively followed since birth. Methods and Results In 1982, all births in the city of Pelotas, southern Brazil, were identified and those children (n = 5,914) whose families lived in the urban area of the city have been followed and evaluated at several time points. The cohort participants were evaluated in 2012–13, and IMT was measured at the posterior wall of the right and left common carotid arteries in longitudinal planes using ultrasound imaging. We obtained valid IMT measurements for 3,188 individuals. Weight-for-age z-score (WAZ) at age 2 years, weight-for-height z-score (WHZ) at age 4, height-for-age z-score (HAZ) at 4 years, WAZ at age 4 and relative conditional weight at 4 years were positively associated with IMT, even after controlling for confounding variables. The beta-coefficient associated with ≥1 s.d. WAZ at age 2 (compared to those with a <–1 s.d.) was 3.62 μm (95% CI 0.86 to 6.38). The beta-coefficient associated with ≥1 s.d. WHZ at 4 (in relation to <–1 s.d) was 3.83 μm (95% CI 0.24 to 7.42). For HAZ at 4, the beta-coefficient for ≥1 s.d. in relation to <–1 s.d. was 4.19 μm (95% CI 1.14 to 7.25). For WAZ at 4, the beta-coefficient associated with ≥1 s.d. in relation to <–1 s.d. was 4.28 μm (95% CI 1.59 to 6.97). The beta-coefficient associated with conditional weight gain at age 2–4 was 1.26 μm (95% CI 0.49 to 2.02). Conclusion IMT at age 30 was positively associated with WAZ at age 2 years, WHZ at age 4, HAZ at age 4, WAZ at age 4 and conditional weight gain at age 4 years. PMID:25611747

  9. ION ACCELERATOR

    DOEpatents

    Bell, J.S.

    1959-09-15

    An arrangement for the drift tubes in a linear accelerator is described whereby each drift tube acts to shield the particles from the influence of the accelerating field and focuses the particles passing through the tube. In one embodiment the drift tube is splii longitudinally into quadrants supported along the axis of the accelerator by webs from a yoke, the quadrants. webs, and yoke being of magnetic material. A magnetic focusing action is produced by energizing a winding on each web to set up a magnetic field between adjacent quadrants. In the other embodiment the quadrants are electrically insulated from each other and have opposite polarity voltages on adjacent quadrants to provide an electric focusing fleld for the particles, with the quadrants spaced sufficienily close enough to shield the particles within the tube from the accelerating electric field.

  10. Acceleration switch

    DOEpatents

    Abbin, J.P. Jr.; Devaney, H.F.; Hake, L.W.

    1979-08-29

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  11. Acceleration switch

    DOEpatents

    Abbin, Jr., Joseph P.; Devaney, Howard F.; Hake, Lewis W.

    1982-08-17

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  12. LINEAR ACCELERATOR

    DOEpatents

    Christofilos, N.C.; Polk, I.J.

    1959-02-17

    Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.

  13. Acupuncture regulates the aging-related changes in gene profile expression of the hippocampus in senescence-accelerated mouse (SAMP10).

    PubMed

    Ding, Xiaorong; Yu, Jianchun; Yu, Tao; Fu, Yu; Han, Jingxian

    2006-05-15

    To examine molecular events in hippocampus associated with aging and acupuncture effect, we employed cDNA arrays providing data of 588 genes to define transcriptional patterns. Male 8-month-old SAMP10 and its homologous SAMRl were selected and randomly divided into four groups: R1 control group (Rc), P10 control group (Pc), P10 acupuncture group (Pa) and P10 non-acupoint group (Pn). The points consisted Shanzhong (CV17), Zhongwan (CV12), Qihai (CV6), Zusanli (ST36) and Xuehai (SP10). In Pa, we found that points stimuli could completely or partly reverse some genes expression profiles in hippocampus with aging. Simultaneously, some genes not related with brain aging were affected by acupuncture as well. Meanwhile, non-acupoint had some effect on aging-unrelated genes expression and little or negative effect on aging-related genes. We verified array results with RT-PCR and Northern blotting for three genes which are related to oxidative damage closely, including Hsp84, Hsp86 and YB-1. In conclusion, acupuncture could be a potential intervention to retard molecular events with aging in mammals. PMID:16516385

  14. Alternative parallel ring protocols

    NASA Technical Reports Server (NTRS)

    Mukkamala, R.; Foudriat, E. C.; Maly, Kurt J.; Kale, V.

    1990-01-01

    Communication protocols are know to influence the utilization and performance of communication network. The effect of two token ring protocols on a gigabit network with multiple ring structure is investigated. In the first protocol, a mode sends at most one message on receiving a token. In the second protocol, a mode sends all the waiting messages when a token is received. The behavior of these protocols is shown to be highly dependent on the number of rings as well as the load in the network.

  15. What Makes a Student Non-Traditional? A Comparison of Students over and under Age 25 in Online, Accelerated Psychology Courses

    ERIC Educational Resources Information Center

    Tilley, Brian P.

    2014-01-01

    The growing proportion of non-traditional students, very commonly defined as students over the age of 25 (though other features vary from study to study) necessitates more studies with this increasingly relevant group participating. Recently, the growth of non-traditional universities such as those offering predominantly online, accelerated…

  16. Accelerated life testing of spacecraft subsystems

    NASA Technical Reports Server (NTRS)

    Wiksten, D.; Swanson, J.

    1972-01-01

    The rationale and requirements for conducting accelerated life tests on electronic subsystems of spacecraft are presented. A method for applying data on the reliability and temperature sensitivity of the parts contained in a sybsystem to the selection of accelerated life test parameters is described. Additional considerations affecting the formulation of test requirements are identified, and practical limitations of accelerated aging are described.

  17. Particle acceleration

    NASA Technical Reports Server (NTRS)

    Vlahos, L.; Machado, M. E.; Ramaty, R.; Murphy, R. J.; Alissandrakis, C.; Bai, T.; Batchelor, D.; Benz, A. O.; Chupp, E.; Ellison, D.

    1986-01-01

    Data is compiled from Solar Maximum Mission and Hinothori satellites, particle detectors in several satellites, ground based instruments, and balloon flights in order to answer fundamental questions relating to: (1) the requirements for the coronal magnetic field structure in the vicinity of the energization source; (2) the height (above the photosphere) of the energization source; (3) the time of energization; (4) transistion between coronal heating and flares; (5) evidence for purely thermal, purely nonthermal and hybrid type flares; (6) the time characteristics of the energization source; (7) whether every flare accelerates protons; (8) the location of the interaction site of the ions and relativistic electrons; (9) the energy spectra for ions and relativistic electrons; (10) the relationship between particles at the Sun and interplanetary space; (11) evidence for more than one acceleration mechanism; (12) whether there is single mechanism that will accelerate particles to all energies and also heat the plasma; and (13) how fast the existing mechanisms accelerate electrons up to several MeV and ions to 1 GeV.

  18. Accelerated Achievement

    ERIC Educational Resources Information Center

    Ford, William J.

    2010-01-01

    This article focuses on the accelerated associate degree program at Ivy Tech Community College (Indiana) in which low-income students will receive an associate degree in one year. The three-year pilot program is funded by a $2.3 million grant from the Lumina Foundation for Education in Indianapolis and a $270,000 grant from the Indiana Commission…

  19. ACCELERATION INTEGRATOR

    DOEpatents

    Pope, K.E.

    1958-01-01

    This patent relates to an improved acceleration integrator and more particularly to apparatus of this nature which is gyrostabilized. The device may be used to sense the attainment by an airborne vehicle of a predetermined velocitv or distance along a given vector path. In its broad aspects, the acceleration integrator utilizes a magnetized element rotatable driven by a synchronous motor and having a cylin drical flux gap and a restrained eddy- current drag cap deposed to move into the gap. The angular velocity imparted to the rotatable cap shaft is transmitted in a positive manner to the magnetized element through a servo feedback loop. The resultant angular velocity of tae cap is proportional to the acceleration of the housing in this manner and means may be used to measure the velocity and operate switches at a pre-set magnitude. To make the above-described dcvice sensitive to acceleration in only one direction the magnetized element forms the spinning inertia element of a free gyroscope, and the outer housing functions as a gimbal of a gyroscope.

  20. Plasma accelerator

    DOEpatents

    Wang, Zhehui; Barnes, Cris W.

    2002-01-01

    There has been invented an apparatus for acceleration of a plasma having coaxially positioned, constant diameter, cylindrical electrodes which are modified to converge (for a positive polarity inner electrode and a negatively charged outer electrode) at the plasma output end of the annulus between the electrodes to achieve improved particle flux per unit of power.

  1. Accelerated ageing experiments with crosslinked and conventional ultra-high molecular weight polyethylene (UHMW-PE) stabilised with alpha-tocopherol for total joint arthroplasty.

    PubMed

    Wolf, C; Macho, C; Lederer, K

    2006-12-01

    Samples of untreated ultra-high molecular weight polyethylene (UHMW-PE), UHMW-PE sterilized with gamma-rays in nitrogen atmosphere (conventional UHMW-PE, widely used for articulating surfaces in endoprostheses) and UHMW-PE, which has been crosslinked by electron beam irradiation and annealed subsequently, were stabilized with alpha-tocopherol and aged in air at 120 degrees C as well as in 10% aqueous hydrogenperoxide with 0.04 mg/ml FeCl3 as catalyst at 50 degrees C. The oxidative degradation was monitored with the help of infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), solubility measurements and size exclusion chromatography (SEC) and were compared to unstabilized samples. When aged in air at 120 degrees C, the crosslinked UHMW-PE showed a slightly slower increase of the carbonyl (CO)-number (according to DIN 53383) in FTIR than conventional UHMW-PE. A stabilisation with 0.4% w/w alpha-tocopherol resulted in an increase of lifetime by a factor of approx. 40 for all samples. Ageing in 10% aqueous H2O2 at 50 degrees C yielded similar results for all three unstabilised samples. The addition of the natural antioxidant alpha-tocopherol led to a prolongation of lifetime by a factor of approx. 2.5. A linear loss of alpha-tocopherol was detected during ageing. An increase of crystallinity as well as lamella thickness during ageing was observed with the help of DSC. The two-phase structure of crosslinked UHMW-PE with two melting endotherms at 114 degrees C and 137 degrees C was replaced very quickly by a single melting point at 130 degrees C. This effect was delayed with the stabilized samples. In the solubility and SEC measurements, a severe molecular degradation and drop of molar mass of all materials could be observed after ageing in H2O2, leading to a complete destruction and, in case of crosslinked UHMW-PE, to a serious damage of the molecular network, respectively. PMID:17143765

  2. A longitudinal study of the impact of chronic psychological stress on health-related quality of life and clinical biomarkers: protocol for the Australian Healthy Aging of Women Study

    PubMed Central

    2014-01-01

    Background Despite advancements in our understanding of the importance of stress reduction in achieving good health, we still only have limited insight into the impact of stress on cellular function. Recent studies have suggested that exposure to prolonged psychological stress may alter an individual’s physiological responses, and contribute to morbidity and mortality. This paper presents an overview of the study protocol we are using to examine the impact of life stressors on lifestyle factors, health-related quality of life and novel and established biomarkers of stress in midlife and older Australian women. The primary aim of this study is to explore the links between chronic psychological stress on both subjective and objective health markers in midlife and older Australian women. The study examines the extent to which exposure frightening, upsetting or stressful events such as natural disasters, illness or death of a relative, miscarriage and relationship conflict is correlated with a variety of objective and subjective health markers. Methods/Design This study is embedded within the longitudinal Healthy Aging of Women’s study which has collected data from midlife and older Australian women at 5 yearly intervals since 2001, and uses the Allostastic model of women’s health by Groër and colleagues in 2010. The current study expands the focus of the HOW study and will assess the impact of life stressors on quality of life and clinical biomarkers in midlife and older Australian women to explain the impact of chronic psychological stress in women. Discussion The proposed study hypothesizes that women are at increased risk of exposure to multiple or repeated stressors, some being unique to women, and the frequency and chronicity of stressors increases women’s risk of adverse health outcomes. This study aims to further our understanding of the relationships between stressful life experiences, perceived quality of life, stress biomarkers, chronic illness, and

  3. Smokeless tobacco use accelerates age-related loss of bone mineral density among older women in a multi-ethnic rural community.

    PubMed

    Quandt, Sara A; Spangler, John G; Case, L Douglas; Bell, Ronny A; Belflower, Amy E

    2005-06-01

    Cigarette smoking is a recognized risk factor for low bone mineral density (BMD) and osteoporosis. Despite the prevalence of smokeless tobacco (ST) use by women in some areas of the United States, minority groups in the United Kingdom, and populations in South Asia and Africa, no data exist to evaluate its effect on bone health. The objective of the study is to identify risk factors for low BMD among older women in a multi-ethnic population, with particular attention to smoking and ST use. Data were collected in Robeson County, North Carolina. ST use from childhood is common among women in this community. Two hundred-forty women aged 60 years and older (approximately equal numbers of African Americans, Native Americans and whites) were recruited at a variety of community events to obtain a cross-section of the demographic composition of the county. The main outcome was BMD measured in the heel using a portable dual energy x-ray absorptiometry. Twenty-nine percent of women were current or former smokers, and 26% current or former ST users. Increased BMD was predicted by greater body mass index, estrogen use in the past year, and African American and Native American ethnicity. There was a significant interaction between ST use and age, and between smoking and nutritional supplement use. BMD declined with age; the decline with age was greater for women who were current or former ST users than for those who never used ST. Women who formerly smoked and did not use supplements had a decreased BMD. ST should be considered as an additional risk factor for osteoporosis in populations where its use is prevalent. PMID:16917747

  4. The rates of change of the stochastic trajectories of acceleration variability are a good predictor of normal aging and of the stage of Parkinson's disease

    PubMed Central

    Torres, Elizabeth B.

    2013-01-01

    The accelerometer data from mobile smart phones provide stochastic trajectories that change over time. This rate of change is unique to each person and can be well-characterized by the continuous two-parameter family of Gamma probability distributions. Accordingly, on the Gamma plane each participant can be uniquely localized by the shape and the scale parameters of the Gamma probability distribution. The scatter of such points contains information that can unambiguously separate the normal controls (NC) from those patients with Parkinson's disease (PD) that are at a later stage of the disease. In general normal aging seems conducive of more predictable patterns of variation in the accelerometer data. Yet this trend breaks down in PD where the statistical signatures seem to be a more relevant predictor of the stage of the disease. Those patients at a later stage of the disease have more random and noisier patterns than those in the earlier stages, whose statistics resemble those of the older NC. Overall the peak rates of change of the stochastic trajectories of the accelerometer are a good predictor of the stage of PD and of the age of a “normally” aging individual. PMID:23882193

  5. Accelerated chemical aging of crystalline nuclear waste forms: A density functional theory study of 109Cdx 109Ag1-x S

    NASA Astrophysics Data System (ADS)

    Dorado, B.; Uberuaga, B. P.; Marks, N. A.; Stanek, C. R.

    2015-06-01

    Recently, a combined experimental-theoretical approach to assess the effect of daughter product formation on the stability of crystalline compounds comprised of radioisotopes has been developed. This methodology was motivated by the potential impact on crystalline nuclear waste form stability of a significant fraction of the constituent atoms undergoing transmutation. What is particularly novel about this approach is the experimental use of very short-lived isotopes to accelerate the chemical evolution that occurs during decay. In this paper, we present results of density functional theory (DFT) calculations that have been performed in support of corresponding experiments on the 109Cdx 109Ag1-x S material system. 109Cd has been selected in order to simulate the decay of important "short-lived" fission products 137Cs or 90Sr (which decay via β - to 137Ba and 90Zr respectively with ≈ 30-year half-lives). By comparison, 109Cd decays by electron capture with a half-life of 109 days to 109Ag. DFT results predict the formation of heretofore unobserved CdxAg1-x S structures, which support corresponding experiments and ultimately may have implications for waste form stability.

  6. Compact accelerator

    DOEpatents

    Caporaso, George J.; Sampayan, Stephen E.; Kirbie, Hugh C.

    2007-02-06

    A compact linear accelerator having at least one strip-shaped Blumlein module which guides a propagating wavefront between first and second ends and controls the output pulse at the second end. Each Blumlein module has first, second, and third planar conductor strips, with a first dielectric strip between the first and second conductor strips, and a second dielectric strip between the second and third conductor strips. Additionally, the compact linear accelerator includes a high voltage power supply connected to charge the second conductor strip to a high potential, and a switch for switching the high potential in the second conductor strip to at least one of the first and third conductor strips so as to initiate a propagating reverse polarity wavefront(s) in the corresponding dielectric strip(s).

  7. Lifetime assessment of atomic-layer-deposited Al2O3-Parylene C bilayer coating for neural interfaces using accelerated age testing and electrochemical characterization.

    PubMed

    Minnikanti, Saugandhika; Diao, Guoqing; Pancrazio, Joseph J; Xie, Xianzong; Rieth, Loren; Solzbacher, Florian; Peixoto, Nathalia

    2014-02-01

    The lifetime and stability of insulation are critical features for the reliable operation of an implantable neural interface device. A critical factor for an implanted insulation's performance is its barrier properties that limit access of biological fluids to the underlying device or metal electrode. Parylene C is a material that has been used in FDA-approved implantable devices. Considered a biocompatible polymer with barrier properties, it has been used as a substrate, insulation or an encapsulation for neural implant technology. Recently, it has been suggested that a bilayer coating of Parylene C on top of atomic-layer-deposited Al2O3 would provide enhanced barrier properties. Here we report a comprehensive study to examine the mean time to failure of Parylene C and Al2O3-Parylene C coated devices using accelerated lifetime testing. Samples were tested at 60°C for up to 3 months while performing electrochemical measurements to characterize the integrity of the insulation. The mean time to failure for Al2O3-Parylene C was 4.6 times longer than Parylene C coated samples. In addition, based on modeling of the data using electrical circuit equivalents, we show here that there are two main modes of failure. Our results suggest that failure of the insulating layer is due to pore formation or blistering as well as thinning of the coating over time. The enhanced barrier properties of the bilayer Al2O3-Parylene C over Parylene C makes it a promising candidate as an encapsulating neural interface.

  8. Accelerated Thermal-Aging-Induced Degradation of Organometal Triiodide Perovskite on ZnO Nanostructures and Its Effect on Hybrid Photovoltaic Devices.

    PubMed

    Kumar, S; Dhar, A

    2016-07-20

    Organometal halide perovskite materials are presently some of the pacesetters for light harvesting in hybrid photovoltaic devices because of their excellent inherent electrical and optical properties. However, long-term durability of such perovskite materials remains a major bottleneck for their commercialization especially in countries with hot and humid climatic conditions, thus violating the international standards for photovoltaic technology. Albeit, TiO2 as an electron-transport layer has been well investigated for perovskite solar cells; the high-temperature processing makes it unsuitable for low-cost and large-scale roll-to-roll production of flexible photovoltaic devices. Herein, we have chosen low-temperature (<150 °C)-processable nanostructured ZnO as the electron-selective layer and used a two-step method for sensitizing ZnO nanorods with methylammonium lead iodide (MAPbI3) perovskite, which is viable for flexible photovoltaic devices. We have also elaborately addressed the effect of the annealing duration on the conversion of a precursor solution into the required perovskite phase on ZnO nanostructures. The investigations show that the presence of ZnO nanostructures accelerates the rate of degradation of MAPbI3 films under ambient annealing and thus requires proper optimization. The role of ZnO in enhancing the degradation kinetics of the perovskite layer has been investigated by X-ray photoelectron spectroscopy and a buffer layer passivation technique. The effect of the annealing duration of the MAPbI3 perovskite on the optical, morphological, and compositional behavior has been closely studied and correlated with the photovoltaic efficiency. The study captures the degradation behavior of the commercially interesting MAPbI3 perovskite on a ZnO electron-transport layer and thus can provide insight for developing alternative families of perovskite material with better thermal and environmental stability for application in low-cost flexible photovoltaic

  9. Accelerated Thermal-Aging-Induced Degradation of Organometal Triiodide Perovskite on ZnO Nanostructures and Its Effect on Hybrid Photovoltaic Devices.

    PubMed

    Kumar, S; Dhar, A

    2016-07-20

    Organometal halide perovskite materials are presently some of the pacesetters for light harvesting in hybrid photovoltaic devices because of their excellent inherent electrical and optical properties. However, long-term durability of such perovskite materials remains a major bottleneck for their commercialization especially in countries with hot and humid climatic conditions, thus violating the international standards for photovoltaic technology. Albeit, TiO2 as an electron-transport layer has been well investigated for perovskite solar cells; the high-temperature processing makes it unsuitable for low-cost and large-scale roll-to-roll production of flexible photovoltaic devices. Herein, we have chosen low-temperature (<150 °C)-processable nanostructured ZnO as the electron-selective layer and used a two-step method for sensitizing ZnO nanorods with methylammonium lead iodide (MAPbI3) perovskite, which is viable for flexible photovoltaic devices. We have also elaborately addressed the effect of the annealing duration on the conversion of a precursor solution into the required perovskite phase on ZnO nanostructures. The investigations show that the presence of ZnO nanostructures accelerates the rate of degradation of MAPbI3 films under ambient annealing and thus requires proper optimization. The role of ZnO in enhancing the degradation kinetics of the perovskite layer has been investigated by X-ray photoelectron spectroscopy and a buffer layer passivation technique. The effect of the annealing duration of the MAPbI3 perovskite on the optical, morphological, and compositional behavior has been closely studied and correlated with the photovoltaic efficiency. The study captures the degradation behavior of the commercially interesting MAPbI3 perovskite on a ZnO electron-transport layer and thus can provide insight for developing alternative families of perovskite material with better thermal and environmental stability for application in low-cost flexible photovoltaic

  10. BICEP's acceleration

    SciTech Connect

    Contaldi, Carlo R.

    2014-10-01

    The recent Bicep2 [1] detection of, what is claimed to be primordial B-modes, opens up the possibility of constraining not only the energy scale of inflation but also the detailed acceleration history that occurred during inflation. In turn this can be used to determine the shape of the inflaton potential V(φ) for the first time — if a single, scalar inflaton is assumed to be driving the acceleration. We carry out a Monte Carlo exploration of inflationary trajectories given the current data. Using this method we obtain a posterior distribution of possible acceleration profiles ε(N) as a function of e-fold N and derived posterior distributions of the primordial power spectrum P(k) and potential V(φ). We find that the Bicep2 result, in combination with Planck measurements of total intensity Cosmic Microwave Background (CMB) anisotropies, induces a significant feature in the scalar primordial spectrum at scales k∼ 10{sup -3} Mpc {sup -1}. This is in agreement with a previous detection of a suppression in the scalar power [2].

  11. The RTS2 protocol

    NASA Astrophysics Data System (ADS)

    Kubánek, Petr; Jelínek, Martin; French, John; Prouza, Michal; Vítek, Stanislav; Castro-Tirado, Alberto J.; Reglero, Victor

    2008-07-01

    Remote Telescope System 2nd version (RTS2) is an open source project aimed at developing a software environment to control a fully robotic observatory. RTS2 consists of various components, which communicate via an ASCII based protocol. As the protocol was from the beginning designed as an observatory control system, it provides some unique features, which are hard to find in the other communication systems. These features include advanced synchronisation mechanisms and strategies for setting variables. This presentation describes the protocol and its unique features. It also assesses protocol performance, and provides examples how the RTS2 library can be used to quickly build an observatory control system.

  12. Evaluation of HVDC cables for the St. Lawrence River crossing of Hydro-Quebec's 500 kV DC line. Part 2; Cable testing facility for dielectric and accelerated aging

    SciTech Connect

    Trinh, N.G.; Couderc, D.; Faucher, P.; Chaaban, M.; Belec, M.; Leduc, J. )

    1992-04-01

    This paper describes the new cable testing facility at IREQ for long-term accelerated aging tests on HV cables. This test facility was required as part of an extensive program to evaluate the high-voltage cables for the river crossing of Hydro-Quebec's new transmission lines rated 800 kV AC and {plus minus}500 kV DC. The first application was for the evaluation of self-contained oil-filled (SCOF) cables for the St. Lawrence river crossing of the {plus minus}500 kV Quebec-New England HVDC power transmission system. The paper also describes the specific dielectric constraints resulting from the insertion of a short length of cable into a long line and, also, the circuits developed for the special tests, which reproduce the specific cable test conditions.

  13. MICROWAVE-ACCELERATED MULTICOMPONENT REACTIONS UNDER SOLVENT-FREE CONDITIONS

    EPA Science Inventory

    The application of microwave-accelerated solventless synthetic protocols in multicomponent (MCC) reactions will be exemplified by several condensation and cyclization reactions including the rapid one-pot assembly of valuable heterocyclic compounds from in situ generated intermed...

  14. Advanced concepts for acceleration

    SciTech Connect

    Keefe, D.

    1986-07-01

    Selected examples of advanced accelerator concepts are reviewed. Such plasma accelerators as plasma beat wave accelerator, plasma wake field accelerator, and plasma grating accelerator are discussed particularly as examples of concepts for accelerating relativistic electrons or positrons. Also covered are the pulsed electron-beam, pulsed laser accelerator, inverse Cherenkov accelerator, inverse free-electron laser, switched radial-line accelerators, and two-beam accelerator. Advanced concepts for ion acceleration discussed include the electron ring accelerator, excitation of waves on intense electron beams, and two-wave combinations. (LEW)

  15. Accelerators and the Accelerator Community

    SciTech Connect

    Malamud, Ernest; Sessler, Andrew

    2008-06-01

    In this paper, standing back--looking from afar--and adopting a historical perspective, the field of accelerator science is examined. How it grew, what are the forces that made it what it is, where it is now, and what it is likely to be in the future are the subjects explored. Clearly, a great deal of personal opinion is invoked in this process.

  16. FRAS1-related extracellular matrix 3 (FREM3) single-nucleotide polymorphism effects on gene expression, amygdala reactivity and perceptual processing speed: An accelerated aging pathway of depression risk.

    PubMed

    Nikolova, Yuliya S; Iruku, Swetha P; Lin, Chien-Wei; Conley, Emily Drabant; Puralewski, Rachel; French, Beverly; Hariri, Ahmad R; Sibille, Etienne

    2015-01-01

    accelerated aging. PMID:26441752

  17. FRAS1-related extracellular matrix 3 (FREM3) single-nucleotide polymorphism effects on gene expression, amygdala reactivity and perceptual processing speed: An accelerated aging pathway of depression risk

    PubMed Central

    Nikolova, Yuliya S.; Iruku, Swetha P.; Lin, Chien-Wei; Conley, Emily Drabant; Puralewski, Rachel; French, Beverly; Hariri, Ahmad R.; Sibille, Etienne

    2015-01-01

    accelerated aging. PMID:26441752

  18. National Sample Assessment Protocols

    ERIC Educational Resources Information Center

    Ministerial Council on Education, Employment, Training and Youth Affairs (NJ1), 2012

    2012-01-01

    These protocols represent a working guide for planning and implementing national sample assessments in connection with the national Key Performance Measures (KPMs). The protocols are intended for agencies involved in planning or conducting national sample assessments and personnel responsible for administering associated tenders or contracts,…

  19. Oral administration of amino acidic supplements improves protein and energy profiles in skeletal muscle of aged rats: elongation of functional performance and acceleration of mitochondrial recovery in adenosine triphosphate after exhaustive exertion.

    PubMed

    Chen Scarabelli, Carol; McCauley, Roy B; Yuan, Zhaokan; Di Rezze, Justin; Patel, David; Putt, Jeff; Raddino, Riccardo; Allebban, Zuhair; Abboud, John; Scarabelli, Gabriele M; Chilukuri, Karuna; Gardin, Julius; Saravolatz, Louis; Faggian, Giuseppe; Mazzucco, Alessandro; Scarabelli, Tiziano M

    2008-06-01

    Sarcopenia is an inevitable age-related degenerative process chiefly characterized by decreased synthesis of muscle proteins and impaired mitochondrial function, leading to progressive loss of muscle mass. Here, we sought to probe whether long-term administration of oral amino acids (AAs) can increase protein and adenosine triphosphate (ATP) content in the gastrocnemius muscle of aged rats, enhancing functional performance. To this end, 6- and 24-month-old male Fisher 344 rats were divided into 3 groups: group A (6-month-old rats) and group B (24-month-old rats) were used as adult and senescent control group, respectively, while group C (24-month-old rats) was used as senescent treated group and underwent 1-month oral treatment with a mixture of mainly essential AAs. Untreated senescent animals exhibited a 30% reduction in total and fractional protein content, as well as a 50% reduction in ATP content and production, compared with adult control rats (p <0.001). Long-term supplementation with mixed AAs significantly improved protein and high-energy phosphate content, as well as the rate of mitochondrial ATP production, conforming their values to those of adult control animals (p <0.001). The improved availability of protein and high-energy substrates in the gastrocnemius muscle of treated aged rats paralleled a significant enhancement in functional performance assessed by swim test, with dramatic elongation of maximal exertion times compared with untreated senescent rats (p <0.001). In line with these findings, we observed that, after 6 hours of rest following exhaustive swimming, the recovery in mitochondrial ATP content was approximately 70% in adult control rats, approximately 60% in senescent control rats, and normalized in treated rats as compared with animals of the same age unexposed to maximal exertion (p <0.001). In conclusion, nutritional supplementation with oral AAs improved protein and energy profiles in the gastrocnemius of treated rats, enhancing

  20. Protocol of the PSYCHOTSH study: association between neonatal thyroid stimulating hormone concentration and intellectual, psychomotor and psychosocial development at 4–5 year of age: a retrospective cohort study

    PubMed Central

    2014-01-01

    Background Several European countries, including Belgium, still suffer from mild iodine deficiency. Thyroid stimulating hormone (TSH) concentration in whole blood measured at birth has been proposed as an indicator of maternal iodine status during the last trimester of pregnancy. It has been shown that mild iodine deficiency during pregnancy may affect the neurodevelopment of the offspring. In several studies, elevated TSH levels at birth were associated with suboptimal cognitive and psychomotor outcomes among young children. This paper describes the protocol of the PSYCHOTSH study aiming to assess the association between neonatal TSH levels and intellectual, psychomotor and psychosocial development of 4–5 year old children. The results could lead to a reassessment of the recommended cut-off levels of 5 > mU/L used for monitoring iodine status of the population. Methods In total, 380 Belgian 4–5 year old preschool children from Brussels and Wallonia with a neonatal blood spot TSH concentration between 0 and 15 mU/L are included in the study. For each sex and TSH-interval (0–1, 1–2, 2–3, 3–4, 4–5, 5–6, 6–7, 7–8, 8–9 and 9–15 mU/L), 19 newborns were randomly selected from all newborns screened by the neonatal screening centre in Brussels in 2008–2009. Infants with congenital hypothyroidism, low birth weight and prematurity were excluded from the study. Neonatal TSH concentration was measured by the Autodelphia method in dried blood spots, collected by heel stick on filter paper 3 to 5 days after birth. Cognitive abilities and psychomotor development are assessed using the Wechsler Preschool and Primary Scale of Intelligence - third edition - and the Charlop-Atwell Scale of Motor coordination. Psychosocial development is measured using the Child Behaviour Check List for age 1½ to 5 years old. In addition, several socioeconomic, parental and child confounding factors are assessed. Conclusions This study aims to clarify the effect of

  1. Montreal protocol: Business opportunites

    SciTech Connect

    1998-12-31

    The Montreal Protocol on Substances that Deplete the Ozone Layer was signed by 24 countries in 1987, establishing measures for controlling the production and consumption of ozone-depleting substances. This publication begins with some background information on ozone depletion and the history of the Protocol. It then describes aspects of the Protocol`s Multilateral Fund, created to assist developing countries to meet Protocol deadlines: Its administration, structure, and how projects are initiated. Names, addresses, and phone/fax numbers of Fund contacts are provided. Canadian projects under the Fund are then reviewed and opportunities for Canadian environmental companies are noted. Finally, information sheets are presented which summarize Fund-related Canadian bilateral projects undertaken to date.

  2. Reliable broadcast protocols

    NASA Technical Reports Server (NTRS)

    Joseph, T. A.; Birman, Kenneth P.

    1989-01-01

    A number of broadcast protocols that are reliable subject to a variety of ordering and delivery guarantees are considered. Developing applications that are distributed over a number of sites and/or must tolerate the failures of some of them becomes a considerably simpler task when such protocols are available for communication. Without such protocols the kinds of distributed applications that can reasonably be built will have a very limited scope. As the trend towards distribution and decentralization continues, it will not be surprising if reliable broadcast protocols have the same role in distributed operating systems of the future that message passing mechanisms have in the operating systems of today. On the other hand, the problems of engineering such a system remain large. For example, deciding which protocol is the most appropriate to use in a certain situation or how to balance the latency-communication-storage costs is not an easy question.

  3. Evaluation of particles released from single-wall carbon nanotube/polymer composites with or without thermal aging by an accelerated abrasion test.

    PubMed

    Jiang, Lin; Kondo, Akira; Shigeta, Masahiro; Endoh, Shigehisa; Uejima, Mitsugu; Ogura, Isamu; Naito, Makio

    2014-01-01

    To provide data required for assessing the environmental health and safety risks of nanocomposites, abrasion-induced particle release from single-wall carbon nanotube (SWCNT)/polymer composites with or without thermal aging were evaluated by a shot blast system. First, overall composite weight loss (i.e., overall particle release) as a result of shot blasting was measured. Incorporating 5 wt% SWCNTs in polystyrene (PS) matrix was observed to reduce overall particle release by approximately 30% compared with pure PS. Heat treatment of the 5 wt% SWCNT/PS composites at 100°C for 10 days induced very slight change in overall particle release due to shot blasting. However, heat treatment at 350°C for 1 hr greatly deteriorated the abrasion resistance of the composites, enhancing overall particle release. Second, to verify the existence and form of SWCNTs released from the composites, released particles were observed by electron microscopy. Micron-sized particles with protruding SWCNTs and submicron-sized SWCNT clusters were observed in the particles released from the composites. Heat treatment of the composites at 350°C for 1 hr enhanced SWCNT release, which mainly formed clusters or rope-like bundles.

  4. Loss of epidermal hypoxia-inducible factor-1α accelerates epidermal aging and affects re-epithelialization in human and mouse.

    PubMed

    Rezvani, Hamid Reza; Ali, Nsrein; Serrano-Sanchez, Martin; Dubus, Pierre; Varon, Christine; Ged, Cécile; Pain, Catherine; Cario-André, Muriel; Seneschal, Julien; Taïeb, Alain; de Verneuil, Hubert; Mazurier, Frédéric

    2011-12-15

    In mouse and human skin, HIF-1α is constitutively expressed in the epidermis, mainly in the basal layer. HIF-1α has been shown to have crucial systemic functions: regulation of kidney erythropoietin production in mice with constitutive HIF-1α epidermal deletion, and hypervascularity following epidermal HIF-1α overexpression. However, its local role in keratinocyte physiology has not been clearly defined. To address the function of HIF-1α in the epidermis, we used the mouse model of HIF-1α knockout targeted to keratinocytes (K14-Cre/Hif1a(flox/flox)). These mice had a delayed skin phenotype characterized by skin atrophy and pruritic inflammation, partly mediated by basement membrane disturbances involving laminin-332 (Ln-332) and integrins. We also investigated the relevance of results of studies in mice to human skin using reconstructed epidermis and showed that HIF-1α knockdown in human keratinocytes impairs the formation of a viable reconstructed epidermis. A diminution of keratinocyte growth potential, following HIF-1α silencing, was associated with a decreased expression of Ln-322 and α6 integrin and β1 integrin. Overall, these results indicate a role of HIF-1α in skin homeostasis especially during epidermal aging.

  5. A RASSF1A polymorphism restricts p53/p73 activation and associates with poor survival and accelerated age of onset of soft tissue sarcoma

    PubMed Central

    Yee, Karen S.; Grochola, Lukasz; Hamilton, Garth; Grawenda, Anna; Bond, Elisabeth E.; Taubert, Helge; Wurl, Peter; Bond, Gareth L.; O’Neill, Eric

    2016-01-01

    RASSF1A (Ras association domain containing family 1A), a tumor suppressor gene that is frequently inactivated in human cancers, is phosphorylated by Ataxia Telangiectasia Mutated (ATM) on Ser131 upon DNA damage, leading to activation of a p73-dependent apoptotic response. A single nucleotide polymorphism located in the region of the key ATM activation site of RASSF1A predicts the conversion of alanine (encoded by the major G-allele) to serine (encoded by the minor T-allele) at residue 133 of RASSF1A (p.Ala133Ser). Secondary protein structure prediction studies suggest that an alpha helix containing the ATM recognition site is disrupted in the serine isoform of RASSF1A (RASSF1A-p.133Ser). In this study, we observed a reduced ability of ATM to recruit and phosphorylate RASSF1A-p.133Ser upon DNA damage. RASSF1A-p.133Ser failed to activate the MST2/LATS pathway, which is required for YAP/p73 mediated apoptosis, and negatively affected the activation of p53, culminating in a defective cellular response to DNA damage. Consistent with a defective p53 response, we found that male soft tissue sarcoma patients carrying the minor T-allele encoding RASSF1A-p.133Ser exhibited poorer tumor-specific survival and earlier age of onset compared with patients homozygous for the major G-allele. Our findings propose a model that suggests a certain subset of the population have inherently weaker p73/p53 activation due to inefficient signaling through RASSF1A, which affects both cancer incidence and survival. PMID:22389451

  6. Reliable multicast protocol specifications protocol operations

    NASA Technical Reports Server (NTRS)

    Callahan, John R.; Montgomery, Todd; Whetten, Brian

    1995-01-01

    This appendix contains the complete state tables for Reliable Multicast Protocol (RMP) Normal Operation, Multi-RPC Extensions, Membership Change Extensions, and Reformation Extensions. First the event types are presented. Afterwards, each RMP operation state, normal and extended, is presented individually and its events shown. Events in the RMP specification are one of several things: (1) arriving packets, (2) expired alarms, (3) user events, (4) exceptional conditions.

  7. Accelerator system and method of accelerating particles

    NASA Technical Reports Server (NTRS)

    Wirz, Richard E. (Inventor)

    2010-01-01

    An accelerator system and method that utilize dust as the primary mass flux for generating thrust are provided. The accelerator system can include an accelerator capable of operating in a self-neutralizing mode and having a discharge chamber and at least one ionizer capable of charging dust particles. The system can also include a dust particle feeder that is capable of introducing the dust particles into the accelerator. By applying a pulsed positive and negative charge voltage to the accelerator, the charged dust particles can be accelerated thereby generating thrust and neutralizing the accelerator system.

  8. Aging gauge

    DOEpatents

    Betts, Robert E.; Crawford, John F.

    1989-01-01

    An aging gauge comprising a container having a fixed or a variable sized t opening with a cap which can be opened to control the sublimation rate of a thermally sublimational material contained within the container. In use, the aging gauge is stored with an item to determine total heat the item is subjected to and also the maximum temperature to which the item has been exposed. The aging gauge container contains a thermally sublimational material such as naphthalene or similar material which has a low sublimation rate over the temperature range from about 70.degree. F. to about 160.degree. F. The aging products determined by analyses of a like item aged along with the aging gauge for which the sublimation amount is determined is employed to establish a calibration curve for future aging evaluation. The aging gauge is provided with a means for determining the maximum temperature exposure (i.e., a thermally indicating material which gives an irreversible color change, Thermocolor pigment). Because of the relationship of doubling reaction rates for increases of 10.degree. C., equivalency of item used in accelerated aging evaluation can be obtained by referring to a calibration curve depicting storage temperature on the abscissa scale and multiplier on the ordinate scale.

  9. Aging gauge

    DOEpatents

    Betts, Robert E.; Crawford, John F.

    1989-04-04

    An aging gauge comprising a container having a fixed or a variable sized t opening with a cap which can be opened to control the sublimation rate of a thermally sublimational material contained within the container. In use, the aging gauge is stored with an item to determine total heat the item is subjected to and also the maximum temperature to which the item has been exposed. The aging gauge container contains a thermally sublimational material such as naphthalene or similar material which has a low sublimation rate over the temperature range from about 70.degree. F. to about 160.degree. F. The aging products determined by analyses of a like item aged along with the aging gauge for which the sublimation amount is determined is employed to establish a calibration curve for future aging evaluation. The aging gauge is provided with a means for determining the maximum temperature exposure (i.e., a thermally indicating material which gives an irreversible color change, Thermocolor pigment). Because of the relationship of doubling reaction rates for increases of 10.degree. C., equivalency of item used in accelerated aging evaluation can be obtained by referring to a calibration curve depicting storage temperature on the abscissa scale and multiplier on the ordinate scale.

  10. Mass spectrometry with accelerators.

    PubMed

    Litherland, A E; Zhao, X-L; Kieser, W E

    2011-01-01

    As one in a series of articles on Canadian contributions to mass spectrometry, this review begins with an outline of the history of accelerator mass spectrometry (AMS), noting roles played by researchers at three Canadian AMS laboratories. After a description of the unique features of AMS, three examples, (14)C, (10)Be, and (129)I are given to illustrate the methods. The capabilities of mass spectrometry have been extended by the addition of atomic isobar selection, molecular isobar attenuation, further ion acceleration, followed by ion detection and ion identification at essentially zero dark current or ion flux. This has been accomplished by exploiting the techniques and accelerators of atomic and nuclear physics. In 1939, the first principles of AMS were established using a cyclotron. In 1977 the selection of isobars in the ion source was established when it was shown that the (14)N(-) ion was very unstable, or extremely difficult to create, making a tandem electrostatic accelerator highly suitable for assisting the mass spectrometric measurement of the rare long-lived radioactive isotope (14)C in the environment. This observation, together with the large attenuation of the molecular isobars (13)CH(-) and (12)CH 2(-) during tandem acceleration and the observed very low background contamination from the ion source, was found to facilitate the mass spectrometry of (14)C to at least a level of (14)C/C ~ 6 × 10(-16), the equivalent of a radiocarbon age of 60,000 years. Tandem Accelerator Mass Spectrometry, or AMS, has now made possible the accurate radiocarbon dating of milligram-sized carbon samples by ion counting as well as dating and tracing with many other long-lived radioactive isotopes such as (10)Be, (26)Al, (36)Cl, and (129)I. The difficulty of obtaining large anion currents with low electron affinities and the difficulties of isobar separation, especially for the heavier mass ions, has prompted the use of molecular anions and the search for alternative

  11. ETHYLENE-INSENSITIVE3 Is a Senescence-Associated Gene That Accelerates Age-Dependent Leaf Senescence by Directly Repressing miR164 Transcription in Arabidopsis[C][W

    PubMed Central

    Li, Zhonghai; Peng, Jinying; Wen, Xing; Guo, Hongwei

    2013-01-01

    Numerous endogenous and environmental signals regulate the intricate and highly orchestrated process of plant senescence. Ethylene is a well-known inducer of senescence, including fruit ripening and flower and leaf senescence. However, the underlying molecular mechanism of ethylene-induced leaf senescence remains to be elucidated. Here, we examine ETHYLENE-INSENSITIVE3 (EIN3), a key transcription factor in ethylene signaling, and find that EIN3 is a functional senescence-associated gene. Constitutive overexpression or temporary activation of EIN3 is sufficient to accelerate leaf senescence symptoms. Conversely, loss of EIN3 and EIN3-Like1 (its close homolog) function leads to a delay in age-dependent and ethylene-, jasmonic acid-, or dark-induced leaf senescence. We further found that EIN3 acts downstream of ORESARA2 (ORE2)/ORE3/EIN2 to repress miR164 transcription and upregulate the transcript levels of ORE1/NAC2, a target gene of miR164. EIN3 directly binds to the promoters of microRNA164 (miR164), and this binding activity progressively increases during leaf ageing. Genetic analysis revealed that overexpression of miR164 or knockout of ORE1/NAC2 represses EIN3-induced early-senescence phenotypes. Collectively, our study defines a continuation of the signaling pathway involving EIN2-EIN3-miR164-NAC2 in regulating leaf senescence and provides a mechanistic insight into how ethylene promotes the progression of leaf senescence in Arabidopsis thaliana. PMID:24064769

  12. Precise clock synchronization protocol

    NASA Astrophysics Data System (ADS)

    Luit, E. J.; Martin, J. M. M.

    1993-12-01

    A distributed clock synchronization protocol is presented which achieves a very high precision without the need for very frequent resynchronizations. The protocol tolerates failures of the clocks: clocks may be too slow or too fast, exhibit omission failures and report inconsistent values. Synchronization takes place in synchronization rounds as in many other synchronization protocols. At the end of each round, clock times are exchanged between the clocks. Each clock applies a convergence function (CF) to the values obtained. This function estimates the difference between its clock and an average clock and corrects its clock accordingly. Clocks are corrected for drift relative to this average clock during the next synchronization round. The protocol is based on the assumption that clock reading errors are small with respect to the required precision of synchronization. It is shown that the CF resynchronizes the clocks with high precision even when relatively large clock drifts are possible. It is also shown that the drift-corrected clocks remain synchronized until the end of the next synchronization round. The stability of the protocol is proven.

  13. Microcomputer-based Acceleration Sensor Device for Swimming Stroke Monitoring

    NASA Astrophysics Data System (ADS)

    Ohgi, Yuji; Ichikawa, Hiroshi; Miyaji, Chikara

    The purpose of this study was to develop a microcomputer-based acceleration logger device for the swimming stroke monitoring. The authors measured the swimmer's tri-axial wrist acceleration and applied this device for the fatigue evaluation of the swimmers. The experimental protocol led the swimmers exhausted after the crawl stroke interval training. Every single stroke was determined by the impact acceleration peak, which appeared on the x and z-axis acceleration. The change of the underwater stroke phases was identified by the characteristics of the acceleration peaks. In their exhaustion, the y-axis acceleration, which was longitudinal forearm acceleration decreased at the beginning of the upsweep phase. At that time, the swimmer could not extend his elbow joint. Since the developed acceleration data logger could provide us the information about the underwater stroke phases and it would be a helpful tool in the swimming training.

  14. A Statistical Perspective on Highly Accelerated Testing.

    SciTech Connect

    Thomas, Edward V.

    2015-02-01

    Highly accelerated life testing has been heavily promoted at Sandia (and elsewhere) as a means to rapidly identify product weaknesses caused by flaws in the product's design or manufacturing process. During product development, a small number of units are forced to fail at high stress. The failed units are then examined to determine the root causes of failure. The identification of the root causes of product failures exposed by highly accelerated life testing can instigate changes to the product's design and/or manufacturing process that result in a product with increased reliability. It is widely viewed that this qualitative use of highly accelerated life testing (often associated with the acronym HALT) can be useful. However, highly accelerated life testing has also been proposed as a quantitative means for "demonstrating" the reliability of a product where unreliability is associated with loss of margin via an identified and dominating failure mechanism. It is assumed that the dominant failure mechanism can be accelerated by changing the level of a stress factor that is assumed to be related to the dominant failure mode. In extreme cases, a minimal number of units (often from a pre-production lot) are subjected to a single highly accelerated stress relative to normal use. If no (or, sufficiently few) units fail at this high stress level, some might claim that a certain level of reliability has been demonstrated (relative to normal use conditions). Underlying this claim are assumptions regarding the level of knowledge associated with the relationship between the stress level and the probability of failure. The primary purpose of this document is to discuss (from a statistical perspective) the efficacy of using accelerated life testing protocols (and, in particular, "highly accelerated" protocols) to make quantitative inferences concerning the performance of a product (e.g., reliability) when in fact there is lack-of-knowledge and uncertainty concerning the

  15. InterGroup Protocols

    2003-04-02

    Existing reliable ordered group communication protocols have been developed for local-area networks and do not in general scale well to a large number of nodes and wide-area networks. The InterGroup suite of protocols is a scalable group communication system that introduces an unusual approach to handling group membership, and supports a receiver-oriented selection of service. The protocols are intended for a wide-area network, with a large number of nodes, that has highly variable delays andmore » a high message loss rate, such as the Internet. The levels of the message delivery service range from unreliable unordered to reliable timestamp ordered.« less

  16. Analysis of energy efficient routing protocols for implementation of a ubiquitous health system

    NASA Astrophysics Data System (ADS)

    Kwon, Jongwon; Park, Yongman; Koo, Sangjun; Ayurzana, Odgeral; Kim, Hiesik

    2007-12-01

    The innovative Ubiquitous-Health was born through convergence of medical service, with development of up to date information technologies and ubiquitous IT. The U-Health can be applied to a variety of special situations for managing functions of each medical center efficiently. This paper focuses on estimation of various routing protocols for implementation of U-health monitoring system. In order to facilitate wireless communication over the network, a routing protocol on the network layer is used to establish precise and efficient route between sensor nodes so that information acquired from sensors may be delivered in a timely manner. A route establishment should be considered to minimize overhead, data loss and power consumption because wireless networks for U-health are organized by a large number of sensor nodes which are small in size and have limited processing power, memory and battery life. In this paper a overview of wireless sensor network technologies commonly known is described as well as evaluation of three multi hop routing protocols which are flooding, gossiping and modified low energy adaptive clustering hierarchy(LEACH) for use with these networks using TOSSIM simulator. As a result of evaluation the integrated wireless sensor board was developed in particular. The board is embedded device based on AVR128 porting TinyOS. Also it employs bio sensor measures blood pressure, pulse frequency and ZigBee module for wireless communication. This paper accelerates the digital convergence age through continual research and development of technologies related the U-Health.

  17. A Survey of Hadron Therapy Accelerator Technologies.

    SciTech Connect

    PEGGS,S.; SATOGATA, T.; FLANZ, J.

    2007-06-25

    Hadron therapy has entered a new age [1]. The number of facilities grows steadily, and 'consumer' interest is high. Some groups are working on new accelerator technology, while others optimize existing designs by reducing capital and operating costs, and improving performance. This paper surveys the current requirements and directions in accelerator technology for hadron therapy.

  18. Optimal protocols for nonlocality distillation

    SciTech Connect

    Hoeyer, Peter; Rashid, Jibran

    2010-10-15

    Forster et al. recently showed that weak nonlocality can be amplified by giving the first protocol that distills a class of nonlocal boxes (NLBs) [Phys. Rev. Lett. 102, 120401 (2009)] We first show that their protocol is optimal among all nonadaptive protocols. We next consider adaptive protocols. We show that the depth-2 protocol of Allcock et al. [Phys. Rev. A 80, 062107 (2009)] performs better than previously known adaptive depth-2 protocols for all symmetric NLBs. We present a depth-3 protocol that extends the known region of distillable NLBs. We give examples of NLBs for which each of the Forster et al., the Allcock et al., and our protocols perform best. The understanding we develop is that there is no single optimal protocol for NLB distillation. The choice of which protocol to use depends on the noise parameters for the NLB.

  19. Comparison of cable ageing

    NASA Astrophysics Data System (ADS)

    Plaček, Vít; Kohout, Tomáš

    2010-03-01

    Two cable types, which currently are used in nuclear power plants (NPP) and which are composed by jacket/insulation materials, i.e. PVC/PVC and PVC/PE, were exposed to accelerated ageing conditions, in order to simulate their behavior after 10 years in service. The cables were aged under two different test conditions: With relatively high accelerating ageing speed:Radiation ageing was carried out at room temperature at a dose rate of 2900 Gy/h, followed by thermal ageing at 100 °C. This accelerated ageing condition was fairly fast, but still in compliance with the standards. With moderate ageing speed:The radiation and thermal ageing was performed simultaneously (superimposed) at a dose rate of 2.7-3.7Gy/h and a temperature of 68-70 °C. Such a test condition seems to be very close to the radiation and temperature impact onto the cables in the real NPP service. Finally, mechanical properties were measured to characterize the ageing status of the cables. The purpose of this study was to compare degradation effects, derived from both ageing methods, and to demonstrate that results obtained from high values of accelerating parameters and from fast ageing simulation can be very different from reality. The observed results corroborated this assumption.

  20. Senescence-accelerated OXYS rats

    PubMed Central

    Stefanova, Natalia A; Kozhevnikova, Oyuna S; Vitovtov, Anton O; Maksimova, Kseniya Yi; Logvinov, Sergey V; Rudnitskaya, Ekaterina A; Korbolina, Elena E; Muraleva, Natalia A; Kolosova, Nataliya G

    2014-01-01

    Senescence-accelerated OXYS rats are an experimental model of accelerated aging that was established from Wistar stock via selection for susceptibility to cataractogenic effects of a galactose-rich diet and via subsequent inbreeding of highly susceptible rats. Currently, we have the 102nd generation of OXYS rats with spontaneously developing cataract and accelerated senescence syndrome, which means early development of a phenotype similar to human geriatric disorders, including accelerated brain aging. In recent years, our group found strong evidence that OXYS rats are a promising model for studies of the mechanisms of brain aging and neurodegenerative processes similar to those seen in Alzheimer disease (AD). The manifestation of behavioral alterations and learning and memory deficits develop since the fourth week of age, i.e., simultaneously with first signs of neurodegeneration detectable on magnetic resonance imaging and under a light microscope. In addition, impaired long-term potentiation has been demonstrated in OXYS rats by the age of 3 months. With age, neurodegenerative changes in the brain of OXYS rats become amplified. We have shown that this deterioration happens against the background of overproduction of amyloid precursor protein (AβPP), accumulation of β-amyloid (Aβ), and hyperphosphorylation of the tau protein in the hippocampus and cortex. The development of AMD-like retinopathy in OXYS rats is also accompanied by increased accumulation of Aβ in the retina. These published data suggest that the OXYS strain may serve as a spontaneous rat model of AD-like pathology and could help to decipher the pathogenesis of AD. PMID:24552807

  1. Development of wide area environment accelerator operation and diagnostics method

    NASA Astrophysics Data System (ADS)

    Uchiyama, Akito; Furukawa, Kazuro

    2015-08-01

    Remote operation and diagnostic systems for particle accelerators have been developed for beam operation and maintenance in various situations. Even though fully remote experiments are not necessary, the remote diagnosis and maintenance of the accelerator is required. Considering remote-operation operator interfaces (OPIs), the use of standard protocols such as the hypertext transfer protocol (HTTP) is advantageous, because system-dependent protocols are unnecessary between the remote client and the on-site server. Here, we have developed a client system based on WebSocket, which is a new protocol provided by the Internet Engineering Task Force for Web-based systems, as a next-generation Web-based OPI using the Experimental Physics and Industrial Control System Channel Access protocol. As a result of this implementation, WebSocket-based client systems have become available for remote operation. Also, as regards practical application, the remote operation of an accelerator via a wide area network (WAN) faces a number of challenges, e.g., the accelerator has both experimental device and radiation generator characteristics. Any error in remote control system operation could result in an immediate breakdown. Therefore, we propose the implementation of an operator intervention system for remote accelerator diagnostics and support that can obviate any differences between the local control room and remote locations. Here, remote-operation Web-based OPIs, which resolve security issues, are developed.

  2. Wear performance of neat and vitamin E blended highly cross-linked PE under severe conditions: The combined effect of accelerated ageing and third body particles during wear test.

    PubMed

    Affatato, Saverio; De Mattia, Jonathan Salvatore; Bracco, Pierangiola; Pavoni, Eleonora; Taddei, Paola

    2016-12-01

    The objective of this study is to evaluate the effects of third-body particles on the in vitro wear behaviour of three different sets of polyethylene acetabular cups after prolonged testing in a hip simulator and accelerated ageing. Vitamin E-blended, cross-linked polyethylene (XLPE_VE), cross-linked polyethylene (XLPE) and conventional polyethylene (STD_PE) acetabular cups were simulator tested for two million cycles under severe conditions (i.e. by adding third-body particles to the bovine calf serum lubricant). Micro-Fourier Transform Infrared and micro-Raman spectroscopic analyses, differential scanning calorimetry, and crosslink density measurements were used to characterize the samples at a molecular level. The STD_PE cups had twice mass loss than the XLPE_VE components and four times than the XLPE samples; statistically significant differences were found between the mass losses of the three sets of cups. The observed wear trend was justified on the basis of the differences in cross-link density among the samples (XLPE>XLPE_VE>STD_PE). FTIR crystallinity profiles, bulk DSC crystallinity and surface micro-Raman crystallinity seemed to have a similar behaviour upon testing: all of them (as well as the all-trans and ortho-trans contents) revealed the most significant changes in XLPE and XLPE_VE samples. The more severe third-body wear testing conditions determined more noticeable changes in all spectroscopic markers with respect to previous tests. Unexpectedly, traces of bulk oxidation were found in both STD_PE (unirradiated) and XLPE (remelting-stabilized), which were expected to be stable to oxidation; on the contrary, XLPE_VE demonstrated a high oxidative stability in the present, highly demanding conditions.

  3. Laser driven ion accelerator

    DOEpatents

    Tajima, Toshiki

    2006-04-18

    A system and method of accelerating ions in an accelerator to optimize the energy produced by a light source. Several parameters may be controlled in constructing a target used in the accelerator system to adjust performance of the accelerator system. These parameters include the material, thickness, geometry and surface of the target.

  4. Donor-specific antibodies accelerate arteriosclerosis after kidney transplantation.

    PubMed

    Hill, Gary S; Nochy, Dominique; Bruneval, Patrick; Duong van Huyen, J P; Glotz, Denis; Suberbielle, Caroline; Zuber, Julien; Anglicheau, Dany; Empana, Jean-Philippe; Legendre, Christophe; Loupy, Alexandre

    2011-05-01

    In biopsies of renal allografts, arteriosclerosis is often more severe than expected based on the age of the donor, even without a history of rejection vasculitis. To determine whether preformed donor-specific antibodies (DSAs) may contribute to the severity of arteriosclerosis, we examined protocol biopsies from patients with (n=40) or without (n=59) DSA after excluding those with any evidence of vasculitis. Among DSA-positive patients, arteriosclerosis significantly progressed between month 3 and month 12 after transplant (mean Banff cv score 0.65 ± 0.11 to 1.12 ± 0.10, P=0.014); in contrast, among DSA-negative patients, we did not detect a statistically significant progression during the same timeframe (mean Banff cv score 0.65 ± 0.11 to 0.81 ± 0.10, P=not significant). Available biopsies at later time points supported a rate of progression of arteriosclerosis in DSA-negative patients that was approximately one third that in DSA-positive patients. Accelerated arteriosclerosis was significantly associated with peritubular capillary leukocytic infiltration, glomerulitis, subclinical antibody-mediated rejection, and interstitial inflammation. In conclusion, these data support the hypothesis that donor-specific antibodies dramatically accelerate post-transplant progression of arteriosclerosis.

  5. Protocols for distributive scheduling

    NASA Technical Reports Server (NTRS)

    Richards, Stephen F.; Fox, Barry

    1993-01-01

    The increasing complexity of space operations and the inclusion of interorganizational and international groups in the planning and control of space missions lead to requirements for greater communication, coordination, and cooperation among mission schedulers. These schedulers must jointly allocate scarce shared resources among the various operational and mission oriented activities while adhering to all constraints. This scheduling environment is complicated by such factors as the presence of varying perspectives and conflicting objectives among the schedulers, the need for different schedulers to work in parallel, and limited communication among schedulers. Smooth interaction among schedulers requires the use of protocols that govern such issues as resource sharing, authority to update the schedule, and communication of updates. This paper addresses the development and characteristics of such protocols and their use in a distributed scheduling environment that incorporates computer-aided scheduling tools. An example problem is drawn from the domain of space shuttle mission planning.

  6. Generalized teleportation protocol

    SciTech Connect

    Gordon, Goren; Rigolin, Gustavo

    2006-04-15

    A generalized teleportation protocol (GTP) for N qubits is presented, where the teleportation channels are nonmaximally entangled and all the free parameters of the protocol are considered: Alice's measurement basis, her sets of acceptable results, and Bob's unitary operations. The full range of fidelity (F) of the teleported state and the probability of success (P{sub suc}) to obtain a given fidelity are achieved by changing these free parameters. A channel efficiency bound is found, where one can determine how to divide it between F and P{sub suc}. A one-qubit formulation is presented and then expanded to N qubits. A proposed experimental setup that implements the GTP is given using linear optics.

  7. Dysphonia risk screening protocol

    PubMed Central

    Nemr, Katia; Simões-Zenari, Marcia; da Trindade Duarte, João Marcos; Lobrigate, Karen Elena; Bagatini, Flavia Alves

    2016-01-01

    OBJECTIVE: To propose and test the applicability of a dysphonia risk screening protocol with score calculation in individuals with and without dysphonia. METHOD: This descriptive cross-sectional study included 365 individuals (41 children, 142 adult women, 91 adult men and 91 seniors) divided into a dysphonic group and a non-dysphonic group. The protocol consisted of 18 questions and a score was calculated using a 10-cm visual analog scale. The measured value on the visual analog scale was added to the overall score, along with other partial scores. Speech samples allowed for analysis/assessment of the overall degree of vocal deviation and initial definition of the respective groups and after six months, the separation of the groups was confirmed using an acoustic analysis. RESULTS: The mean total scores were different between the groups in all samples. Values ranged between 37.0 and 57.85 in the dysphonic group and between 12.95 and 19.28 in the non-dysphonic group, with overall means of 46.09 and 15.55, respectively. High sensitivity and specificity were demonstrated when discriminating between the groups with the following cut-off points: 22.50 (children), 29.25 (adult women), 22.75 (adult men), and 27.10 (seniors). CONCLUSION: The protocol demonstrated high sensitivity and specificity in differentiating groups of individuals with and without dysphonia in different sample groups and is thus an effective instrument for use in voice clinics. PMID:27074171

  8. Mars Communication Protocols

    NASA Technical Reports Server (NTRS)

    Kazz, G. J.; Greenberg, E.

    2000-01-01

    Over the next decade, international plans and commitments are underway to develop an infrastructure at Mars to support future exploration of the red planet. The purpose of this infrastructure is to provide reliable global communication and navigation coverage for on-approach, landed, roving, and in-flight assets at Mars. The claim is that this infrastructure will: 1) eliminate the need of these assets to carry Direct to Earth (DTE) communications equipment, 2) significantly increase data return and connectivity, 3) enable small mission exploration of Mars without DTE equipment, 4) provide precision navigation i.e., 10 to 100m position resolution, 5) supply timing reference accurate to 10ms. This paper in particular focuses on two CCSDS recommendations for that infrastructure: CCSDS Proximity-1 Space Link Protocol and CCSDS File Delivery Protocol (CFDP). A key aspect of Mars exploration will be the ability of future missions to interoperate. These protocols establish a framework for interoperability by providing standard communication, navigation, and timing services. In addition, these services include strategies to recover gracefully from communication interruptions and interference while ensuring backward compatibility with previous missions from previous phases of exploration.

  9. Satellite Communications Using Commercial Protocols

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.; Griner, James H.; Dimond, Robert; Frantz, Brian D.; Kachmar, Brian; Shell, Dan

    2000-01-01

    NASA Glenn Research Center has been working with industry, academia, and other government agencies in assessing commercial communications protocols for satellite and space-based applications. In addition, NASA Glenn has been developing and advocating new satellite-friendly modifications to existing communications protocol standards. This paper summarizes recent research into the applicability of various commercial standard protocols for use over satellite and space- based communications networks as well as expectations for future protocol development. It serves as a reference point from which the detailed work can be readily accessed. Areas that will be addressed include asynchronous-transfer-mode quality of service; completed and ongoing work of the Internet Engineering Task Force; data-link-layer protocol development for unidirectional link routing; and protocols for aeronautical applications, including mobile Internet protocol routing for wireless/mobile hosts and the aeronautical telecommunications network protocol.

  10. Robust Optimization of Biological Protocols

    PubMed Central

    Flaherty, Patrick; Davis, Ronald W.

    2015-01-01

    When conducting high-throughput biological experiments, it is often necessary to develop a protocol that is both inexpensive and robust. Standard approaches are either not cost-effective or arrive at an optimized protocol that is sensitive to experimental variations. We show here a novel approach that directly minimizes the cost of the protocol while ensuring the protocol is robust to experimental variation. Our approach uses a risk-averse conditional value-at-risk criterion in a robust parameter design framework. We demonstrate this approach on a polymerase chain reaction protocol and show that our improved protocol is less expensive than the standard protocol and more robust than a protocol optimized without consideration of experimental variation. PMID:26417115

  11. Overview of wideband packet protocols

    NASA Astrophysics Data System (ADS)

    Sherif, M. H.

    1992-10-01

    Wideband packet networks operate at rates equal to, or higher than, 64 kb/s, but lower than the basic broadband rate of 150 Mb/s, on cables or satellite links. Wideband packet protocols are the transmission protocols for these networks. They define open interfaces that can be used for public and private ISDNs. The protocols are defined in CCITT Recommendations G.764 and G.765. This paper describes the objectives of the wideband protocols, and how the objectives were achieved.

  12. Age-Status Labeling in Homosexual Men

    ERIC Educational Resources Information Center

    Minnigerode, Fred A.

    1976-01-01

    Homosexual men (N=95) between 25 and 68 years of age were asked to classify themselves as young, middle-aged, or old. The popular suggestion of accelerated aging in homosexual men was not supported. (Author)

  13. Communication complexity protocols for qutrits

    SciTech Connect

    Tamir, Boaz

    2007-03-15

    Consider a function where its entries are distributed among many parties. Suppose each party is allowed to send only a limited amount of information to a referee. The referee can use a classical protocol to compute the value of the global function. Is there a quantum protocol improving the results of all classical protocols? In a recent work Brukner et al. showed the deep connection between such problems and the theory of Bell inequalities. Here we generalize the theory to trits. There, the best classical protocol fails whereas the quantum protocol yields the correct answer.

  14. TURBULENT SHEAR ACCELERATION

    SciTech Connect

    Ohira, Yutaka

    2013-04-10

    We consider particle acceleration by large-scale incompressible turbulence with a length scale larger than the particle mean free path. We derive an ensemble-averaged transport equation of energetic charged particles from an extended transport equation that contains the shear acceleration. The ensemble-averaged transport equation describes particle acceleration by incompressible turbulence (turbulent shear acceleration). We find that for Kolmogorov turbulence, the turbulent shear acceleration becomes important on small scales. Moreover, using Monte Carlo simulations, we confirm that the ensemble-averaged transport equation describes the turbulent shear acceleration.

  15. The direction of acceleration

    NASA Astrophysics Data System (ADS)

    Wilhelm, Thomas; Burde, Jan-Philipp; Lück, Stephan

    2015-11-01

    Acceleration is a physical quantity that is difficult to understand and hence its complexity is often erroneously simplified. Many students think of acceleration as equivalent to velocity, a ˜ v. For others, acceleration is a scalar quantity, which describes the change in speed Δ|v| or Δ|v|/Δt (as opposed to the change in velocity). The main difficulty with the concept of acceleration therefore lies in developing a correct understanding of its direction. The free iOS app AccelVisu supports students in acquiring a correct conception of acceleration by showing acceleration arrows directly at moving objects.

  16. Optical Circuit Switched Protocol

    NASA Technical Reports Server (NTRS)

    Monacos, Steve P. (Inventor)

    2000-01-01

    The present invention is a system and method embodied in an optical circuit switched protocol for the transmission of data through a network. The optical circuit switched protocol is an all-optical circuit switched network and includes novel optical switching nodes for transmitting optical data packets within a network. Each optical switching node comprises a detector for receiving the header, header detection logic for translating the header into routing information and eliminating the header, and a controller for receiving the routing information and configuring an all optical path within the node. The all optical path located within the node is solely an optical path without having electronic storage of the data and without having optical delay of the data. Since electronic storage of the header is not necessary and the initial header is eliminated by the first detector of the first switching node. multiple identical headers are sent throughout the network so that subsequent switching nodes can receive and read the header for setting up an optical data path.

  17. Protocol Architecture Model Report

    NASA Technical Reports Server (NTRS)

    Dhas, Chris

    2000-01-01

    NASA's Glenn Research Center (GRC) defines and develops advanced technology for high priority national needs in communications technologies for application to aeronautics and space. GRC tasked Computer Networks and Software Inc. (CNS) to examine protocols and architectures for an In-Space Internet Node. CNS has developed a methodology for network reference models to support NASA's four mission areas: Earth Science, Space Science, Human Exploration and Development of Space (REDS), Aerospace Technology. This report applies the methodology to three space Internet-based communications scenarios for future missions. CNS has conceptualized, designed, and developed space Internet-based communications protocols and architectures for each of the independent scenarios. The scenarios are: Scenario 1: Unicast communications between a Low-Earth-Orbit (LEO) spacecraft inspace Internet node and a ground terminal Internet node via a Tracking and Data Rela Satellite (TDRS) transfer; Scenario 2: Unicast communications between a Low-Earth-Orbit (LEO) International Space Station and a ground terminal Internet node via a TDRS transfer; Scenario 3: Multicast Communications (or "Multicasting"), 1 Spacecraft to N Ground Receivers, N Ground Transmitters to 1 Ground Receiver via a Spacecraft.

  18. Accelerating Particles with Plasma

    SciTech Connect

    Litos, Michael; Hogan, Mark

    2014-11-05

    Researchers at SLAC explain how they use plasma wakefields to accelerate bunches of electrons to very high energies over only a short distance. Their experiments offer a possible path for the future of particle accelerators.

  19. Accelerator Technology Division

    NASA Astrophysics Data System (ADS)

    1992-04-01

    In fiscal year (FY) 1991, the Accelerator Technology (AT) division continued fulfilling its mission to pursue accelerator science and technology and to develop new accelerator concepts for application to research, defense, energy, industry, and other areas of national interest. This report discusses the following programs: The Ground Test Accelerator Program; APLE Free-Electron Laser Program; Accelerator Transmutation of Waste; JAERI, OMEGA Project, and Intense Neutron Source for Materials Testing; Advanced Free-Electron Laser Initiative; Superconducting Super Collider; The High-Power Microwave Program; (Phi) Factory Collaboration; Neutral Particle Beam Power System Highlights; Accelerator Physics and Special Projects; Magnetic Optics and Beam Diagnostics; Accelerator Design and Engineering; Radio-Frequency Technology; Free-Electron Laser Technology; Accelerator Controls and Automation; Very High-Power Microwave Sources and Effects; and GTA Installation, Commissioning, and Operations.

  20. Linear accelerator: A concept

    NASA Technical Reports Server (NTRS)

    Mutzberg, J.

    1972-01-01

    Design is proposed for inexpensive accelerometer which would work by applying pressure to fluid during acceleration. Pressure is used to move shuttle, and shuttle movement is sensed and calibrated to give acceleration readings.

  1. Improved plasma accelerator

    NASA Technical Reports Server (NTRS)

    Cheng, D. Y.

    1971-01-01

    Converging, coaxial accelerator electrode configuration operates in vacuum as plasma gun. Plasma forms by periodic injections of high pressure gas that is ionized by electrical discharges. Deflagration mode of discharge provides acceleration, and converging contours of plasma gun provide focusing.

  2. MEQALAC rf accelerating structure

    SciTech Connect

    Keane, J.; Brodowski, J.

    1981-01-01

    A prototype MEQALAC capable of replacing the Cockcroft Walton pre-injector at BNL is being fabricated. Ten milliamperes of H/sup -/ beam supplied from a source sitting at a potential of -40 kilovolt is to be accelerated to 750 keV. This energy gain is provided by a 200 Megahertz accelerating system rather than the normal dc acceleration. Substantial size and cost reduction would be realized by such a system over conventional pre-accelerator systems.

  3. Acceleration gradient of a plasma wakefield accelerator

    SciTech Connect

    Uhm, Han S.

    2008-02-25

    The phase velocity of the wakefield waves is identical to the electron beam velocity. A theoretical analysis indicates that the acceleration gradient of the wakefield accelerator normalized by the wave breaking amplitude is K{sub 0}({xi})/K{sub 1}({xi}), where K{sub 0}({xi}) and K{sub 1}({xi}) are the modified Bessel functions of the second kind of order zero and one, respectively and {xi} is the beam parameter representing the beam intensity. It is also shown that the beam density must be considerably higher than the diffuse plasma density for the large radial velocity of plasma electrons that are required for a high acceleration gradient.

  4. Acceleration: It's Elementary

    ERIC Educational Resources Information Center

    Willis, Mariam

    2012-01-01

    Acceleration is one tool for providing high-ability students the opportunity to learn something new every day. Some people talk about acceleration as taking a student out of step. In actuality, what one is doing is putting a student in step with the right curriculum. Whole-grade acceleration, also called grade-skipping, usually happens between…

  5. Far field acceleration

    SciTech Connect

    Fernow, R.C.

    1995-07-01

    Far fields are propagating electromagnetic waves far from their source, boundary surfaces, and free charges. The general principles governing the acceleration of charged particles by far fields are reviewed. A survey of proposed field configurations is given. The two most important schemes, Inverse Cerenkov acceleration and Inverse free electron laser acceleration, are discussed in detail.

  6. Angular Acceleration without Torque?

    ERIC Educational Resources Information Center

    Kaufman, Richard D.

    2012-01-01

    Hardly. Just as Robert Johns qualitatively describes angular acceleration by an internal force in his article "Acceleration Without Force?" here we will extend the discussion to consider angular acceleration by an internal torque. As we will see, this internal torque is due to an internal force acting at a distance from an instantaneous center.

  7. Effectiveness of a website and mobile phone based physical activity and nutrition intervention for middle-aged males: Trial protocol and baseline findings of the ManUp Study

    PubMed Central

    2012-01-01

    Background Compared to females, males experience higher rates of chronic disease and mortality, yet few health promotion initiatives are specifically aimed at men. Therefore, the aim of the ManUp Study is to examine the effectiveness of an IT-based intervention to increase the physical activity and nutrition behaviour and literacy in middle-aged males (aged 35–54 years). Method/Design The study design was a two-arm randomised controlled trial, having an IT-based (applying website and mobile phones) and a print-based intervention arm, to deliver intervention materials and to promote self-monitoring of physical activity and nutrition behaviours. Participants (n = 317) were randomised on a 2:1 ratio in favour of the IT-based intervention arm. Both intervention arms completed assessments at baseline, 3, and 9 months. All participants completed self-report assessments of physical activity, sitting time, nutrition behaviours, physical activity and nutrition literacy, perceived health status and socio-demographic characteristics. A randomly selected sub-sample in the IT-based (n = 61) and print-based (n = 30) intervention arms completed objective measures of height, weight, waist circumference, and physical activity as measured by accelerometer (Actigraph GT3X). The average age of participants in the IT-based and print-based intervention arm was 44.2 and 43.8 years respectively. The majority of participants were employed in professional occupations (IT-based 57.6%, Print-based 54.2%) and were overweight or obese (IT-based 90.8%, Print-based 87.3%). At baseline a lower proportion of participants in the IT-based (70.2%) group agreed that 30 minutes of physical activity each day is enough to improve health compared to the print-based (82.3%) group (p = .026). The IT-based group consumed a significantly lower number of serves of red meat in the previous week, compared to the print-based group (p = .017). No other significant between

  8. Licklider Transmission Protocol Implementation

    NASA Technical Reports Server (NTRS)

    Burleigh, Scott C.; Krupiarz, Chris

    2011-01-01

    This software is an implementation of the Licklider Transmission Protocol (LTP), a communications protocol intended to support the Bundle Protocol in Delay-Tolerant Network (DTN) operations. LTP is designed to provide retransmission-based reliability over links characterized by extremely long message round-trip times and/or frequent interruptions in connectivity. Communication in interplanetary space is the most prominent example of this sort of environment, and LTP is principally aimed at supporting long-haul reliable transmission over deep-space RF links. Like any reliable transport service employing ARQ (Automatic Repeat re-Quests), LTP is stateful. In order to assure the reception of a block of data it has sent, LTP must retain for possible retransmission all portions of that block which might not have been received yet. In order to do so, it must keep track of which portions of the block are known to have been received so far, and which are not, together with any additional information needed for purposes of retransmitting part, or all, of the block. Long round-trip times mean substantial delay between the transmission of a block of data and the reception of an acknowledgement from the block s destination, signaling arrival of the block. If LTP postponed transmission of additional blocks of data until it received acknowledgement of the arrival of all prior blocks, valuable opportunities to use what little deep space transmission bandwidth is available would be forever lost. For this reason, LTP is based in part on a notion of massive state retention. Any number of requested transmission conversations (sessions) may be concurrently in flight at various displacements along the link between two LTP engines, and the LTP engines must necessarily retain transmission status and retransmission resources for all of them. Moreover, if any of the data of a given block are lost en route, it will be necessary to retain the state of that transmission during an additional

  9. Prevalence, Motivations, and Social, Mental Health and Health Consequences of Cyberbullying Among School-Aged Children and Youth: Protocol of a Longitudinal and Multi-Perspective Mixed Method Study

    PubMed Central

    McInroy, Lauren B; Lacombe-Duncan, Ashley; Bhole, Payal; Van Wert, Melissa; Schwan, Kaitlin; Birze, Arija; Daciuk, Joanne; Beran, Tanya; Craig, Wendy; Pepler, Debra J; Wiener, Judith; Khoury-Kassabri, Mona; Johnston, David

    2016-01-01

    Background While the online environment may promote important developmental and social benefits, it also enables the serious and rapidly growing issue of cyberbullying. Cyberbullying constitutes an increasing public health problem – victimized children and youth experience a range of health and mental health concerns, including emotional and psychosomatic problems, maladaptive behaviors, and increased suicidality. Perpetrators demonstrate a lack of empathy, and may also struggle with health and mental health issues. Objective This paper describes the protocols applied in a longitudinal and multi-perspective mixed-methods study with five objectives: (1) to explore children/youth’s experiences, and children/youth’s, parents’, and teachers’ conceptions, definitions, and understanding of cyberbullying; (2) to explore how children/youth view the underlying motivations for cyberbullying; (3) to document the shifting prevalence rates of cyberbullying victimization, witnessing, and perpetration; (4) to identify risk and protective factors for cyberbullying involvement; and (5) to explore social, mental health, and health consequences of cyberbullying. Methods Quantitative survey data were collected over three years (2012-2014) from a stratified random baseline sample of fourth (n=160), seventh (n=243), and tenth (n=267) grade children/youth, their parents (n=246), and their teachers (n=103). Quantitative data were collected from students and teachers during in-person school visits, and from parents via mail-in surveys. Student, parent, and teacher surveys included questions regarding: student experiences with bullying/cyberbullying; student health, mental health, and social and behavioral issues; socio-demographics; and information and communication technology use. In-depth semi-structured qualitative interviews were conducted twice with a sub-sample of students (n=57), purposively selected based on socio-demographics and cyberbullying experience, twice with

  10. Clinical Protocol Information System

    PubMed Central

    Wirtschafter, David D.; Gams, Richard; Ferguson, Carol; Blackwell, William; Boackle, Paul

    1980-01-01

    The Clinical Protocol Information System (CPIS) supports the clinical research and patient care objectives of the SouthEastern Cancer Study Group (SEG). The information system goals are to improve the evaluability of clinical trials, decrease the frequency of adverse patient events, implement drug toxicity surveillance, improve the availability of study data and demonstrate the criteria for computer networks that can impact on the general medical care of the community. Nodes in the network consist of Data General MicroNova MP-100 minicomputers that drive the interactive data dialogue and communicate with the network concentrator (another DG MicroNova) in Birmingham. Functions supported include: source data editing, care “advice,” care “audit,” care “explanation,” and treatment note printing. The complete database is updated nightly and resides on UAB's IBM 370/158-AP.

  11. Compact Plasma Accelerator

    NASA Technical Reports Server (NTRS)

    Foster, John E.

    2004-01-01

    A plasma accelerator has been conceived for both material-processing and spacecraft-propulsion applications. This accelerator generates and accelerates ions within a very small volume. Because of its compactness, this accelerator could be nearly ideal for primary or station-keeping propulsion for spacecraft having masses between 1 and 20 kg. Because this accelerator is designed to generate beams of ions having energies between 50 and 200 eV, it could also be used for surface modification or activation of thin films.

  12. High brightness electron accelerator

    DOEpatents

    Sheffield, Richard L.; Carlsten, Bruce E.; Young, Lloyd M.

    1994-01-01

    A compact high brightness linear accelerator is provided for use, e.g., in a free electron laser. The accelerator has a first plurality of acclerating cavities having end walls with four coupling slots for accelerating electrons to high velocities in the absence of quadrupole fields. A second plurality of cavities receives the high velocity electrons for further acceleration, where each of the second cavities has end walls with two coupling slots for acceleration in the absence of dipole fields. The accelerator also includes a first cavity with an extended length to provide for phase matching the electron beam along the accelerating cavities. A solenoid is provided about the photocathode that emits the electons, where the solenoid is configured to provide a substantially uniform magnetic field over the photocathode surface to minimize emittance of the electons as the electrons enter the first cavity.

  13. Fiber Accelerating Structures

    SciTech Connect

    Hammond, Andrew P.; /Reed Coll. /SLAC

    2010-08-25

    One of the options for future particle accelerators are photonic band gap (PBG) fiber accelerators. PBG fibers are specially designed optical fibers that use lasers to excite an electric field that is used to accelerate electrons. To improve PBG accelerators, the basic parameters of the fiber were tested to maximize defect size and acceleration. Using the program CUDOS, several accelerating modes were found that maximized these parameters for several wavelengths. The design of multiple defects, similar to having closely bound fibers, was studied to find possible coupling or the change of modes. The amount of coupling was found to be dependent on distance separated. For certain distances accelerating coupled modes were found and examined. In addition, several non-periodic fiber structures were examined using CUDOS. The non-periodic fibers produced several interesting results and promised more modes given time to study them in more detail.

  14. A protocol for storage and long-distance shipment of Mediterranean fruit fly (Diptera: Tephritidae) eggs. 1. Effect of temperature, embryo age , and storage time on survival and quality

    SciTech Connect

    Caceres, C.; Wornoayporn, V.; Islam, S.M.; Ahmad, S.

    2007-03-15

    The operational use of Mediterranean fruit fly (medfly) Ceratitis capitata (Wiedemann), genetic sexing strains in Sterile Insect Technique applications can be maximized by developing methods for effective shipment of eggs. This would enable a central production facility to maintain the relevant mother stocks and large colonies to supply eggs to satellite centers that would mass produce only males for irradiation and release. In order to achieve this, the survival of medfly embryos of different ages was assessed after storage at 5, 10, 15, 20, and 25 deg. C in water for different periods of time. Survival was affected by all 3 variables, i.e., embryo age, water temperature, and length of storage. Storage of embryos at any temperature for 120 h resulted in almost no survival. Controlling the age of the embryo at the time of the temperature treatment is crucial for the success of this procedure. Embryos collected between 0 to 12 h after oviposition and pre-incubated at 25 deg. C for 12 h provide a suitable 72 h window for shipment when maintained between 10 to 15 deg. C. Under these conditions, no significant reductions in survival during all the developmental stages were observed. (author) [Spanish] El uso operacional de cepas de la mosca del mediterraneo Ceratitis capitata (Wiedemann) en las cuales es posible separar los sexos a traves de mecanismos geneticos para su utilizacion en la Tecnica del Insecto Esteril (TIE), puede ser maximizado con el desarrollo de metodos efectivos para el envio y transporte de huevos. Esto permite que un laboratorio de produccion centralizada mantenga las respectivas colonias responsables por la produccion de huevos para este abastecer laboratorios satelites responsables por la produccion masiva de solamente machos para subsiguiente irradiacion y liberacion. Para ser posible esta alternativa fue evaluada la supervivencia de embriones de diferentes edades despues de su almacenamiento en agua a 5, 10, 15, 20 y 25 deg. C por diferentes

  15. Indoor air quality investigation protocols

    SciTech Connect

    Greene, R.E.; Williams, P.L.

    1996-10-01

    Over the past 10 to 15 years, an increasing number of complaints about discomfort and health effects related to indoor air quality (IAQ) have been reported. The increase in complaints has been accompanied by an increase in requests for IAQ investigations. This study presents an overview of the many IAQ investigation protocols published since 1984. For analysis, the protocols are divided into four categories: solution-oriented, building diagnostics, industrial hygiene, and epidemiology. In general, the protocols begin with general observations, proceed to collect more specific data as indicated, and end with conclusions and recommendations. A generic IAQ protocol is presented that incorporates the common aspects of the various protocols. All of the current protocols place heavy emphasis on the ventilation system during the investigation. A major problem affecting all of the current protocols is the lack of generally accepted IAQ standards. IN addition, the use of questionnaires, occupant interviews, and personal diaries (as well as the point in the investigation at which they are administered) differs among the protocols. Medical evaluations and verification procedures also differ among the protocols.

  16. Reward feedback accelerates motor learning.

    PubMed

    Nikooyan, Ali A; Ahmed, Alaa A

    2015-01-15

    Recent findings have demonstrated that reward feedback alone can drive motor learning. However, it is not yet clear whether reward feedback alone can lead to learning when a perturbation is introduced abruptly, or how a reward gradient can modulate learning. In this study, we provide reward feedback that decays continuously with increasing error. We asked whether it is possible to learn an abrupt visuomotor rotation by reward alone, and if the learning process could be modulated by combining reward and sensory feedback and/or by using different reward landscapes. We designed a novel visuomotor learning protocol during which subjects experienced an abruptly introduced rotational perturbation. Subjects received either visual feedback or reward feedback, or a combination of the two. Two different reward landscapes, where the reward decayed either linearly or cubically with distance from the target, were tested. Results demonstrate that it is possible to learn from reward feedback alone and that the combination of reward and sensory feedback accelerates learning. An analysis of the underlying mechanisms reveals that although reward feedback alone does not allow for sensorimotor remapping, it can nonetheless lead to broad generalization, highlighting a dissociation between remapping and generalization. Also, the combination of reward and sensory feedback accelerates learning without compromising sensorimotor remapping. These findings suggest that the use of reward feedback is a promising approach to either supplement or substitute sensory feedback in the development of improved neurorehabilitation techniques. More generally, they point to an important role played by reward in the motor learning process.

  17. Acceleration in astrophysics

    SciTech Connect

    Colgate, S.A.

    1993-12-31

    The origin of cosmic rays and applicable laboratory experiments are discussed. Some of the problems of shock acceleration for the production of cosmic rays are discussed in the context of astrophysical conditions. These are: The presumed unique explanation of the power law spectrum is shown instead to be a universal property of all lossy accelerators; the extraordinary isotropy of cosmic rays and the limited diffusion distances implied by supernova induced shock acceleration requires a more frequent and space-filling source than supernovae; the near perfect adiabaticity of strong hydromagnetic turbulence necessary for reflecting the accelerated particles each doubling in energy roughly 10{sup 5} to {sup 6} scatterings with negligible energy loss seems most unlikely; the evidence for acceleration due to quasi-parallel heliosphere shocks is weak. There is small evidence for the expected strong hydromagnetic turbulence, and instead, only a small number of particles accelerate after only a few shock traversals; the acceleration of electrons in the same collisionless shock that accelerates ions is difficult to reconcile with the theoretical picture of strong hydromagnetic turbulence that reflects the ions. The hydromagnetic turbulence will appear adiabatic to the electrons at their much higher Larmor frequency and so the electrons should not be scattered incoherently as they must be for acceleration. Therefore the electrons must be accelerated by a different mechanism. This is unsatisfactory, because wherever electrons are accelerated these sites, observed in radio emission, may accelerate ions more favorably. The acceleration is coherent provided the reconnection is coherent, in which case the total flux, as for example of collimated radio sources, predicts single charge accelerated energies much greater than observed.

  18. Protocol for Birmingham Atrial Fibrillation Treatment of the Aged study (BAFTA): a randomised controlled trial of warfarin versus aspirin for stroke prevention in the management of atrial fibrillation in an elderly primary care population [ISRCTN89345269

    PubMed Central

    Mant, Jonathan WF; Richards, Suzanne H; Hobbs, FD Richard; Fitzmaurice, David; Lip, Gregory YH; Murray, Ellen; Banting, Miriam; Fletcher, Kate; Rahman, Joy; Allan, Teresa; Raftery, James; Bryan, Stirling

    2003-01-01

    Background Atrial fibrillation (AF) is an important independent risk factor for stroke. Randomised controlled trials have shown that this risk can be reduced substantially by treatment with warfarin or more modestly by treatment with aspirin. Existing trial data for the effectiveness of warfarin are drawn largely from studies in selected secondary care populations that under-represent the elderly. The Birmingham Atrial Fibrillation Treatment of the Aged (BAFTA) study will provide evidence of the risks and benefits of warfarin versus aspirin for the prevention of stroke for older people with AF in a primary care setting. Study design A randomised controlled trial where older patients with AF are randomised to receive adjusted dose warfarin or aspirin. Patients will be followed up at three months post-randomisation, then at six monthly intervals there after for an average of three years by their general practitioner. Patients will also receive an annual health questionnaire. 1240 patients will be recruited from over 200 practices in England. Patients must be aged 75 years or over and have AF. Patients will be excluded if they have a history of any of the following conditions: rheumatic heart disease; major non-traumatic haemorrhage; intra-cranial haemorrhage; oesophageal varices; active endoscopically proven peptic ulcer disease; allergic hypersensitivity to warfarin or aspirin; or terminal illness. Patients will also be excluded if the GP considers that there are clinical reasons to treat a patient with warfarin in preference to aspirin (or vice versa). The primary end-point is fatal or non-fatal disabling stroke (ischaemic or haemorrhagic) or significant arterial embolism. Secondary outcomes include major extra-cranial haemorrhage, death (all cause, vascular), hospital admissions (all cause, vascular), cognition, quality of life, disability and compliance with study medication. PMID:12939169

  19. Effect of oral nitrates on pulse pressure and arterial elasticity in patients aged over 65 years with refractory isolated systolic hypertension: study protocol for a randomized controlled trial

    PubMed Central

    2013-01-01

    Background Isolated systolic hypertension is a highly prevalent disease among the elderly. The little available evidence on the efficacy of nitrates for treating the disease is based on small experimental studies. Methods/design We performed a multicenter, randomized, double-blind, phase III, placebo-controlled trial in 154 patients aged over 65 years with refractory isolated systolic hypertension. Patients were randomized to placebo or 40 mg/day of extended-release isosorbide mononitrate added to standard therapy and titrated to 60 mg/day at week 6 if blood pressure exceeded 140/90 mmHg. The primary objective was to assess the effect on clinical pulse pressure of extended-release isosorbide mononitrate added to standard therapy in patients aged over 65 years with refractory isolated systolic hypertension after 3 months of treatment. The secondary objectives were as follows: to quantify the effect of adding the study drug on central blood pressure and vascular compliance using the augmentation index and pulse wave velocity; to evaluate the safety profile by recording adverse effects (frequency, type, severity) and the percentage of patients who had to withdraw from the trial because of adverse events; to quantify the percentage of patients who reach a clinical systolic blood pressure <140 mmHg or <130 mmHg measured by ambulatory blood pressure monitoring; and to quantify the change in pulse pressure measured by ambulatory blood pressure monitoring. Discussion Few clinical trials have been carried out to test the effect of oral nitrates on isolated systolic hypertension, even though these agents seem to be effective. Treatment with extended-release isosorbide mononitrate could improve control of systolic blood pressure without severe side effects, thus helping to reduce the morbidity and mortality of the disease. Trial registration EUDRACT Number: 2012-002988-10 PMID:24228894

  20. Arthroscopic partial meniscectomy in middle-aged patients with mild or no knee osteoarthritis: a protocol for a double-blind, randomized sham-controlled multi-centre trial

    PubMed Central

    2013-01-01

    Background Arthroscopic partial meniscectomy has been shown to be of no benefit to patients with concomitant knee osteoarthritis, but the optimal treatment of a degenerative meniscus tear in patients with mild or no knee osteoarthritis is unknown. This article describes the rationale and methodology of a randomized sham-controlled trial to assess the benefit of arthroscopic partial meniscectomy of a medial meniscus tear in patients with mild or no knee osteoarthritis. The objective of the study is to test whether the benefit from arthroscopic partial meniscectomy in patients with knee pain, medial meniscus lesion and mild/no knee osteoarthritis, is greater after arthroscopic partial meniscectomy than following sham surgery. Methods We will conduct a randomized controlled trial of treatment for degenerative meniscus tears in middle-aged patients (aged 35–55 years) with an MRI-verified medial meniscus lesion and mild or no knee radiographic osteoarthritis (grade 0–2 on the Kellgren & Lawrence scale). Patients will be randomized to receive either conventional arthroscopic partial meniscectomy or a sham surgery procedure. The primary outcome will be the KOOS5 derived from the ‘Knee Injury and Osteoarthritis Outcome Score’ at 2 years follow-up. Secondary outcomes at 2 years will include all five individual subscales of the KOOS, a global perceived effect score, the Short-Form-36 health status score, EQ-5D for economic appraisal and objective tests of muscle strength and physical function. Radiographic knee osteoarthritis will be evaluated at 5 years. Discussion Demonstration of no additional benefit from arthroscopic partial meniscectomy on pain and function should lead to a change in clinical care of patients with a degenerative meniscus tear. The results of this study will provide empirical evidence for the potential benefit/harm of arthroscopic partial meniscectomy compared to a masked sham-therapeutics intervention. Trial registration NCT01264991 PMID

  1. Adult Rhabdomyosarcoma Survival Improved With Treatment on Multimodality Protocols

    SciTech Connect

    Gerber, Naamit Kurshan; Wexler, Leonard H.; Singer, Samuel; Alektiar, Kaled M.; Keohan, Mary Louise; Shi, Weiji; Zhang, Zhigang; Wolden, Suzanne

    2013-05-01

    Purpose: Rhabdomyosarcoma (RMS) is a pediatric sarcoma rarely occurring in adults. For unknown reasons, adults with RMS have worse outcomes than do children. Methods and Materials: We analyzed data from all patients who presented to Memorial Sloan-Kettering Cancer Center between 1990 and 2011 with RMS diagnosed at age 16 or older. One hundred forty-eight patients met the study criteria. Ten were excluded for lack of adequate data. Results: The median age was 28 years. The histologic diagnoses were as follows: embryonal 54%, alveolar 33%, pleomorphic 12%, and not otherwise specified 2%. The tumor site was unfavorable in 67% of patients. Thirty-three patients (24%) were at low risk, 61 (44%) at intermediate risk, and 44 (32%) at high risk. Forty-six percent were treated on or according to a prospective RMS protocol. The 5-year rate of overall survival (OS) was 45% for patients with nonmetastatic disease. The failure rates at 5 years for patients with nonmetastatic disease were 34% for local failure and 42% for distant failure. Among patients with nonmetastatic disease (n=94), significant factors associated with OS were histologic diagnosis, site, risk group, age, and protocol treatment. On multivariate analysis, risk group and protocol treatment were significant after adjustment for age. The 5-year OS was 54% for protocol patients versus 36% for nonprotocol patients. Conclusions: Survival in adult patients with nonmetastatic disease was significantly improved for those treated on RMS protocols, most of which are now open to adults.

  2. “Pre-schoolers in the playground” an outdoor physical activity intervention for children aged 18 months to 4 years old: study protocol for a pilot cluster randomised controlled trial

    PubMed Central

    2013-01-01

    Background The pre-school years are considered critical for establishing healthy lifestyle behaviours such as physical activity. Levels of physical activity track through childhood into adulthood, thus establishing habitual physical activity early in life is vital. Time spent outdoors is associated with greater physical activity and playground interventions have been shown to increase physical activity in school aged children. There are few pre-school, playground-based interventions, and evaluations of these have found mixed results. A recent report published by the UK Chief Medical Officer (CMO) highlighted that new interventions to promote movement in the early years (0–5 years old) are needed. The aim of this study is to undertake a pilot cluster randomised controlled trial (RCT) of an outdoor playground-based physical activity intervention for parents and their children aged 18 months to 4 years old (“Pre-schoolers in the Playground”; PiP) and to assess the feasibility of conducting a full scale cluster RCT. The PiP intervention is grounded in behavioural theory (Social Cognitive Theory), and is in accordance with the CMO guidance for physical activity in the early years. It is informed by existing literature and data collected from focus groups with parents. Methods/Design One hundred and fifty pre-school children affiliated to 10 primary schools will be recruited. Schools will be randomised to either the PiP intervention arm or the control arm (usual practice). Children in the intervention arm will be invited to attend three 30 minute outdoor play sessions per week for 30 weeks (3 school terms) at the school. Feasibility will be assessed by examining recruitment rates, attendance, attrition, acceptability of the trial and of the PiP intervention to parents, fidelity of intervention implementation, capability and capacity for schools to deliver the intervention. Health outcomes and the feasibility of outcome measurement tools will be assessed. These

  3. Multi-centre cluster randomised trial comparing a community group exercise programme with home based exercise with usual care for people aged 65 and over in primary care: protocol of the ProAct 65+ trial

    PubMed Central

    2010-01-01

    Background Regular physical activity reduces the risk of mortality from all causes, with a powerful beneficial effect on risk of falls and hip fractures. However, physical activity levels are low in the older population and previous studies have demonstrated only modest, short-term improvements in activity levels with intervention. Design/Methods Pragmatic 3 arm parallel design cluster controlled trial of class-based exercise (FAME), home-based exercise (OEP) and usual care amongst older people (aged 65 years and over) in primary care. The primary outcome is the achievement of recommended physical activity targets 12 months after cessation of intervention. Secondary outcomes include functional assessments, predictors of exercise adherence, the incidence of falls, fear of falling, quality of life and continuation of physical activity after intervention, over a two-year follow up. An economic evaluation including participant and NHS costs will be embedded in the clinical trial. Discussion The ProAct65 trial will explore and evaluate the potential for increasing physical activity among older people recruited through general practice. The trial will be conducted in a relatively unselected population, and will address problems of selective recruitment, potentially low retention rates, variable quality of interventions and falls risk. Trial Registration Trial Registration: ISRCTN43453770 PMID:20082696

  4. Publishing protocols for partnered research.

    PubMed

    Hysong, Sylvia J; Woodard, LeChauncy; Garvin, Jennifer H; Murawsky, Jeffrey; Petersen, Laura A

    2014-12-01

    Published scientific protocols are advocated as a means of controlling bias in research reporting. Indeed, many journals require a study protocol with manuscript submission. However, publishing protocols of partnered research (PPR) can be challenging in light of the research model's dynamic nature, especially as no current reporting standards exist. Nevertheless, as these protocols become more prevalent, a priori documentation of methods in partnered research studies becomes increasingly important. Using as illustration a suite of studies aimed at improving coordination and communication in the primary care setting, we sought to identify challenges in publishing PPR relative to traditional designs, present alternative solutions to PPR publication, and propose an initial checklist of content to be included in protocols of partnered research. Challenges to publishing PPR include reporting details of research components intended to be co-created with operational partners, changes to sampling and entry strategy, and alignment of scientific and operational goals. Proposed solutions include emulating reporting standards of qualitative research, participatory action research, and adaptive trial designs, as well as embracing technological tools that facilitate publishing adaptive protocols, with version histories that are able to be updated as major protocol changes occur. Finally, we present a proposed checklist of reporting elements for partnered research protocols. PMID:25355092

  5. The simulation of communication protocols

    NASA Astrophysics Data System (ADS)

    de Carvalho Viola, F. E.

    1985-12-01

    Simulators for communication protocols specified in the ESTELLE and LC/1 languages are developed. The general principles of protocol simulation are reviewed; ESTELLE and LC/1 are characterized; a prototype LC/1 simulator based on predicate Petri nets is described; and a detailed specification for a driving interface for an ESTELLE simulator is given.

  6. Publishing protocols for partnered research.

    PubMed

    Hysong, Sylvia J; Woodard, LeChauncy; Garvin, Jennifer H; Murawsky, Jeffrey; Petersen, Laura A

    2014-12-01

    Published scientific protocols are advocated as a means of controlling bias in research reporting. Indeed, many journals require a study protocol with manuscript submission. However, publishing protocols of partnered research (PPR) can be challenging in light of the research model's dynamic nature, especially as no current reporting standards exist. Nevertheless, as these protocols become more prevalent, a priori documentation of methods in partnered research studies becomes increasingly important. Using as illustration a suite of studies aimed at improving coordination and communication in the primary care setting, we sought to identify challenges in publishing PPR relative to traditional designs, present alternative solutions to PPR publication, and propose an initial checklist of content to be included in protocols of partnered research. Challenges to publishing PPR include reporting details of research components intended to be co-created with operational partners, changes to sampling and entry strategy, and alignment of scientific and operational goals. Proposed solutions include emulating reporting standards of qualitative research, participatory action research, and adaptive trial designs, as well as embracing technological tools that facilitate publishing adaptive protocols, with version histories that are able to be updated as major protocol changes occur. Finally, we present a proposed checklist of reporting elements for partnered research protocols.

  7. The Dielectric Wall Accelerator

    SciTech Connect

    Caporaso, George J.; Chen, Yu-Jiuan; Sampayan, Stephen E.

    2009-01-01

    The Dielectric Wall Accelerator (DWA), a class of induction accelerators, employs a novel insulating beam tube to impress a longitudinal electric field on a bunch of charged particles. The surface flashover characteristics of this tube may permit the attainment of accelerating gradients on the order of 100 MV/m for accelerating pulses on the order of a nanosecond in duration. A virtual traveling wave of excitation along the tube is produced at any desired speed by controlling the timing of pulse generating modules that supply a tangential electric field to the tube wall. Because of the ability to control the speed of this virtual wave, the accelerator is capable of handling any charge to mass ratio particle; hence it can be used for electrons, protons and any ion. The accelerator architectures, key technologies and development challenges will be described.

  8. Switched matrix accelerator

    SciTech Connect

    Whittum, David H.; Tantawi, Sami G.

    2001-01-01

    We describe a new concept for a microwave circuit functioning as a charged-particle accelerator at mm wavelengths, permitting an accelerating gradient higher than conventional passive circuits can withstand consistent with cyclic fatigue. The device provides acceleration for multiple bunches in parallel channels, and permits a short exposure time for the conducting surface of the accelerating cavities. Our analysis includes scalings based on a smooth transmission line model and a complementary treatment with a coupled-cavity simulation. We also provide an electromagnetic design for the accelerating structure, arriving at rough dimensions for a seven-cell accelerator matched to standard waveguide and suitable for bench tests at low power in air at 91.392 GHz. A critical element in the concept is a fast mm-wave switch suitable for operation at high power, and we present the considerations for implementation in an H-plane tee. We discuss the use of diamond as the photoconductor switch medium.

  9. Switched Matrix Accelerator

    SciTech Connect

    Whittum, David H

    2000-10-04

    We describe a new concept for a microwave circuit functioning as a charged-particle accelerator at mm-wavelengths, permitting an accelerating gradient higher than conventional passive circuits can withstand consistent with cyclic fatigue. The device provides acceleration for multiple bunches in parallel channels, and permits a short exposure time for the conducting surface of the accelerating cavities. Our analysis includes scalings based on a smooth transmission line model and a complementary treatment with a coupled-cavity simulation. We provide also an electromagnetic design for the accelerating structure, arriving at rough dimensions for a seven-cell accelerator matched to standard waveguide and suitable for bench tests at low power in air at 91.392. GHz. A critical element in the concept is a fast mm-wave switch suitable for operation at high-power, and we present the considerations for implementation in an H-plane tee. We discuss the use of diamond as the photoconductor switch medium.

  10. Wake field accelerators

    SciTech Connect

    Wilson, P.B.

    1986-02-01

    In a wake field accelerator a high current driving bunch injected into a structure or plasma produces intense induced fields, which are in turn used to accelerate a trailing charge or bunch. The basic concepts of wake field acceleration are described. Wake potentials for closed cavities and periodic structures are derived, as are wake potentials on a collinear path with a charge distribution. Cylindrically symmetric structures excited by a beam in the form of a ring are considered. (LEW)

  11. ACCELERATION RESPONSIVE SWITCH

    DOEpatents

    Chabrek, A.F.; Maxwell, R.L.

    1963-07-01

    An acceleration-responsive device with dual channel capabilities whereby a first circuit is actuated upon attainment of a predetermined maximum acceleration level and when the acceleration drops to a predetermined minimum acceleriltion level another circuit is actuated is described. A fluid-damped sensing mass slidably mounted in a relatively frictionless manner on a shaft through the intermediation of a ball bushing and biased by an adjustable compression spring provides inertially operated means for actuating the circuits. (AEC)

  12. Optically pulsed electron accelerator

    DOEpatents

    Fraser, John S.; Sheffield, Richard L.

    1987-01-01

    An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radio frequency powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

  13. Optically pulsed electron accelerator

    DOEpatents

    Fraser, J.S.; Sheffield, R.L.

    1985-05-20

    An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radiofrequency-powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

  14. Acceleration of polarized protons in circular accelerators

    SciTech Connect

    Courant, E.D.; Ruth, R.D.

    1980-09-12

    The theory of depolarization in circular accelerators is presented. The spin equation is first expressed in terms of the particle orbit and then converted to the equivalent spinor equation. The spinor equation is then solved for three different situations: (1) a beam on a flat top near a resonance, (2) uniform acceleration through an isolated resonance, and (3) a model of a fast resonance jump. Finally, the depolarization coefficient, epsilon, is calculated in terms of properties of the particle orbit and the results are applied to a calculation of depolarization in the AGS.

  15. Charged particle accelerator grating

    DOEpatents

    Palmer, Robert B.

    1986-01-01

    A readily disposable and replaceable accelerator grating for a relativistic particle accelerator. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams into the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.

  16. Particle acceleration in flares

    NASA Technical Reports Server (NTRS)

    Benz, Arnold O.; Kosugi, Takeo; Aschwanden, Markus J.; Benka, Steve G.; Chupp, Edward L.; Enome, Shinzo; Garcia, Howard; Holman, Gordon D.; Kurt, Victoria G.; Sakao, Taro

    1994-01-01

    Particle acceleration is intrinsic to the primary energy release in the impulsive phase of solar flares, and we cannot understand flares without understanding acceleration. New observations in soft and hard X-rays, gamma-rays and coherent radio emissions are presented, suggesting flare fragmentation in time and space. X-ray and radio measurements exhibit at least five different time scales in flares. In addition, some new observations of delayed acceleration signatures are also presented. The theory of acceleration by parallel electric fields is used to model the spectral shape and evolution of hard X-rays. The possibility of the appearance of double layers is further investigated.

  17. Accelerator-based BNCT.

    PubMed

    Kreiner, A J; Baldo, M; Bergueiro, J R; Cartelli, D; Castell, W; Thatar Vento, V; Gomez Asoia, J; Mercuri, D; Padulo, J; Suarez Sandin, J C; Erhardt, J; Kesque, J M; Valda, A A; Debray, M E; Somacal, H R; Igarzabal, M; Minsky, D M; Herrera, M S; Capoulat, M E; Gonzalez, S J; del Grosso, M F; Gagetti, L; Suarez Anzorena, M; Gun, M; Carranza, O

    2014-06-01

    The activity in accelerator development for accelerator-based BNCT (AB-BNCT) both worldwide and in Argentina is described. Projects in Russia, UK, Italy, Japan, Israel, and Argentina to develop AB-BNCT around different types of accelerators are briefly presented. In particular, the present status and recent progress of the Argentine project will be reviewed. The topics will cover: intense ion sources, accelerator tubes, transport of intense beams, beam diagnostics, the (9)Be(d,n) reaction as a possible neutron source, Beam Shaping Assemblies (BSA), a treatment room, and treatment planning in realistic cases.

  18. Accelerator-based BNCT.

    PubMed

    Kreiner, A J; Baldo, M; Bergueiro, J R; Cartelli, D; Castell, W; Thatar Vento, V; Gomez Asoia, J; Mercuri, D; Padulo, J; Suarez Sandin, J C; Erhardt, J; Kesque, J M; Valda, A A; Debray, M E; Somacal, H R; Igarzabal, M; Minsky, D M; Herrera, M S; Capoulat, M E; Gonzalez, S J; del Grosso, M F; Gagetti, L; Suarez Anzorena, M; Gun, M; Carranza, O

    2014-06-01

    The activity in accelerator development for accelerator-based BNCT (AB-BNCT) both worldwide and in Argentina is described. Projects in Russia, UK, Italy, Japan, Israel, and Argentina to develop AB-BNCT around different types of accelerators are briefly presented. In particular, the present status and recent progress of the Argentine project will be reviewed. The topics will cover: intense ion sources, accelerator tubes, transport of intense beams, beam diagnostics, the (9)Be(d,n) reaction as a possible neutron source, Beam Shaping Assemblies (BSA), a treatment room, and treatment planning in realistic cases. PMID:24365468

  19. Charged particle accelerator grating

    DOEpatents

    Palmer, Robert B.

    1986-09-02

    A readily disposable and replaceable accelerator grating for a relativistic particle accelerator. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams into the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.

  20. Contrast-enhanced MR Angiography of the Abdomen with Highly Accelerated Acquisition Techniques

    PubMed Central

    Mostardi, Petrice M.; Glockner, James F.; Young, Phillip M.

    2011-01-01

    Purpose: To demonstrate that highly accelerated (net acceleration factor [Rnet] ≥ 10) acquisition techniques can be used to generate three-dimensional (3D) subsecond timing images, as well as diagnostic-quality high-spatial-resolution contrast material–enhanced (CE) renal magnetic resonance (MR) angiograms with a single split dose of contrast material. Materials and Methods: All studies were approved by the institutional review board and were HIPAA compliant; written consent was obtained from all participants. Twenty-two studies were performed in 10 female volunteers (average age, 47 years; range, 27–62 years) and six patients with renovascular disease (three women; average age, 48 years; range, 37–68 years; three men; average age, 60 years; range, 50–67 years; composite average age, 54 years; range, 38–68 years). The two-part protocol consisted of a low-dose (2 mL contrast material) 3D timing image with approximate 1-second frame time, followed by a high-spatial-resolution (1.0–1.6-mm isotropic voxels) breath-hold 3D renal MR angiogram (18 mL) over the full abdominal field of view. Both acquisitions used two-dimensional (2D) sensitivity encoding acceleration factor (R) of eight and 2D homodyne (HD) acceleration (RHD) of 1.4–1.8 for Rnet = R · RHD of 10 or higher. Statistical analysis included determination of mean values and standard deviations of image quality scores performed by two experienced reviewers with use of eight evaluation criteria. Results: The 2-mL 3D time-resolved image successfully portrayed progressive arterial filling in all 22 studies and provided an anatomic overview of the vasculature. Successful timing was also demonstrated in that the renal MR angiogram showed adequate or excellent portrayal of the main renal arteries in 21 of 22 studies. Conclusion: Two-dimensional acceleration techniques with Rnet of 10 or higher can be used in CE MR angiography to acquire (a) a 3D image series with 1-second frame time, allowing accurate

  1. PACE-UP (Pedometer and consultation evaluation - UP) – a pedometer-based walking intervention with and without practice nurse support in primary care patients aged 45–75 years: study protocol for a randomised controlled trial

    PubMed Central

    2013-01-01

    and incremental cost per change in step-count and per quality adjusted life year. Qualitative evaluations will explore reasons for trial non-participation and the interventions’ acceptability. Discussion The PACE-UP trial will determine the effectiveness and cost-effectiveness of a pedometer-based walking intervention delivered by post or practice nurse to less active primary care patients aged 45–75 years old. Approaches to minimise bias and challenges anticipated in delivery will be discussed. Trial registration ISRCTN98538934 PMID:24304838

  2. Protocols.io: Virtual Communities for Protocol Development and Discussion.

    PubMed

    Teytelman, Leonid; Stoliartchouk, Alexei; Kindler, Lori; Hurwitz, Bonnie L

    2016-08-01

    The detailed know-how to implement research protocols frequently remains restricted to the research group that developed the method or technology. This knowledge often exists at a level that is too detailed for inclusion in the methods section of scientific articles. Consequently, methods are not easily reproduced, leading to a loss of time and effort by other researchers. The challenge is to develop a method-centered collaborative platform to connect with fellow researchers and discover state-of-the-art knowledge. Protocols.io is an open-access platform for detailing, sharing, and discussing molecular and computational protocols that can be useful before, during, and after publication of research results.

  3. Effects of Rapid High Temperature Cyclic Aging on a Fully-Formulated Lean NOx Trap Catalyst

    SciTech Connect

    Ottinger, Nathan; Nguyen, Ke; Bunting, Bruce G; Toops, Todd J; Howe, Janet E

    2009-01-01

    In this study, high-temperature deactivation of a fully-formulated lean NOx trap (LNT) is investigated with an accelerated aging protocol where accelerated aging is accomplished by rapid temperature cycling and by higher temperatures. Thermal aging is carried out in a bench-flow reactor at nominal temperatures of 700, 800, 900, and 1000 C using an aging cycle consisting of a 130s lean-phase and a 50s rich-phase. After a prescribed number of lean/rich aging cycles, the NOx conversion of the aged LNT is evaluated at 200, 300, and 400 C. The NOx performance is obtained at a GHSV of 30,000 h-1 using an evaluation cycle consisting of a 60s lean-phase and 5s rich-phase. The effects of aging on the LNT washcoat are determined with EPMA, XRD, STEM/EDS, and BET. Aging at 700 and 800 C has a minimal effect on LNT performance and material properties. However, at aging temperatures of 900 and 1000 C reduction in surface area and sintering of PGM particles are observed and result in a drastic reduction in NOx conversion. Additionally, after aging at 900 C and 1000 C the NOx storage medium, BaCO3, is no longer visible in the XRD patterns, even though a Ba-phase identified by EPMA still exists in all aged samples. BaAl2O4 is not identified at any aging temperatures; possibly due to stabilization effects provided by washcoat additives present in this particular LNT.

  4. Tools for remote computing in accelerator control

    NASA Astrophysics Data System (ADS)

    Anderssen, Pal S.; Frammery, Veronique; Wilcke, Rainer

    1990-08-01

    In modern accelerator control systems, the intelligence of the equipment is distributed in the geographical and the logical sense. Control processes for a large variety of tasks reside in both the equipment and the control computers. Hence successful operation hinges on the availability and reliability of the communication infrastructure. The computers are interconnected by a communication system and use remote procedure calls and message passing for information exchange. These communication mechanisms need a well-defined convention, i.e. a protocol. They also require flexibility in both the setup and changes to the protocol specification. The Network Compiler is a tool which provides the programmer with a means of establising such a protocol for his application. Input to the Network Compiler is a single Interface Description File provided by the programmer. This file is written according to a grammar, and completely specifies the interprocess communication interfaces. Passed through the Network Compiler, the Interface Description File automatically produces the additional source code needed for the protocol. Hence the programmer does not have to be concerned about the details of the communication calls. Any further additions and modifications are made easy, because all the information about the interface is kept in a single file.

  5. Angular velocities, angular accelerations, and coriolis accelerations

    NASA Technical Reports Server (NTRS)

    Graybiel, A.

    1975-01-01

    Weightlessness, rotating environment, and mathematical analysis of Coriolis acceleration is described for man's biological effective force environments. Effects on the vestibular system are summarized, including the end organs, functional neurology, and input-output relations. Ground-based studies in preparation for space missions are examined, including functional tests, provocative tests, adaptive capacity tests, simulation studies, and antimotion sickness.

  6. Accelerators Beyond The Tevatron?

    SciTech Connect

    Lach, Joseph; /Fermilab

    2010-07-01

    Following the successful operation of the Fermilab superconducting accelerator three new higher energy accelerators were planned. They were the UNK in the Soviet Union, the LHC in Europe, and the SSC in the United States. All were expected to start producing physics about 1995. They did not. Why?

  7. Accelerators Beyond The Tevatron?

    SciTech Connect

    Lach, Joseph

    2010-07-29

    Following the successful operation of the Fermilab superconducting accelerator three new higher energy accelerators were planned. They were the UNK in the Soviet Union, the LHC in Europe, and the SSC in the United States. All were expected to start producing physics about 1995. They did not. Why?.

  8. Accelerators (4/5)

    ScienceCinema

    None

    2016-07-12

    1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

  9. Induction linear accelerators

    NASA Astrophysics Data System (ADS)

    Birx, Daniel

    1992-03-01

    Among the family of particle accelerators, the Induction Linear Accelerator is the best suited for the acceleration of high current electron beams. Because the electromagnetic radiation used to accelerate the electron beam is not stored in the cavities but is supplied by transmission lines during the beam pulse it is possible to utilize very low Q (typically<10) structures and very large beam pipes. This combination increases the beam breakup limited maximum currents to of order kiloamperes. The micropulse lengths of these machines are measured in 10's of nanoseconds and duty factors as high as 10-4 have been achieved. Until recently the major problem with these machines has been associated with the pulse power drive. Beam currents of kiloamperes and accelerating potentials of megavolts require peak power drives of gigawatts since no energy is stored in the structure. The marriage of liner accelerator technology and nonlinear magnetic compressors has produced some unique capabilities. It now appears possible to produce electron beams with average currents measured in amperes, peak currents in kiloamperes and gradients exceeding 1 MeV/meter, with power efficiencies approaching 50%. The nonlinear magnetic compression technology has replaced the spark gap drivers used on earlier accelerators with state-of-the-art all-solid-state SCR commutated compression chains. The reliability of these machines is now approaching 1010 shot MTBF. In the following paper we will briefly review the historical development of induction linear accelerators and then discuss the design considerations.

  10. Accelerators (3/5)

    ScienceCinema

    None

    2016-07-12

    1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

  11. Accelerators (5/5)

    ScienceCinema

    None

    2016-07-12

    1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

  12. Accelerators (5/5)

    SciTech Connect

    2009-07-09

    1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

  13. Accelerators (4/5)

    SciTech Connect

    2009-07-08

    1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

  14. Accelerators (3/5)

    SciTech Connect

    2009-07-07

    1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

  15. Ion Induction Accelerators

    NASA Astrophysics Data System (ADS)

    Barnard, John J.; Horioka, Kazuhiko

    The description of beams in RF and induction accelerators share many common features. Likewise, there is considerable commonality between electron induction accelerators (see Chap. 7) and ion induction accelerators. However, in contrast to electron induction accelerators, there are fewer ion induction accelerators that have been operated as application-driven user facilities. Ion induction accelerators are envisioned for applications (see Chap. 10) such as Heavy Ion Fusion (HIF), High Energy Density Physics (HEDP), and spallation neutron sources. Most ion induction accelerators constructed to date have been limited scale facilities built for feasibility studies for HIF and HEDP where a large numbers of ions are required on target in short pulses. Because ions are typically non-relativistic or weakly relativistic in much of the machine, space-charge effects can be of crucial importance. This contrasts the situation with electron machines, which are usually strongly relativistic leading to weaker transverse space-charge effects and simplified longitudinal dynamics. Similarly, the bunch structure of ion induction accelerators relative to RF machines results in significant differences in the longitudinal physics.

  16. Particle Acceleration in Jets

    NASA Technical Reports Server (NTRS)

    Nishikawa, Ken-Ichi

    2005-01-01

    Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., active galactic nuclei (AGNs), gamma ray burst (GRBs), and Galactic microquasar systems usually have power-law emission spectra. Fermi acceleration is the mechanism usually assumed for the acceleration of particles in astrophysical environments.

  17. Microscale acceleration history discriminators

    DOEpatents

    Polosky, Marc A.; Plummer, David W.

    2002-01-01

    A new class of micromechanical acceleration history discriminators is claimed. These discriminators allow the precise differentiation of a wide range of acceleration-time histories, thereby allowing adaptive events to be triggered in response to the severity (or lack thereof) of an external environment. Such devices have applications in airbag activation, and other safety and surety applications.

  18. Diagnostics for induction accelerators

    SciTech Connect

    Fessenden, T.J.

    1996-04-01

    The induction accelerator was conceived by N. C. Christofilos and first realized as the Astron accelerator that operated at LLNL from the early 1960`s to the end of 1975. This accelerator generated electron beams at energies near 6 MeV with typical currents of 600 Amperes in 400 ns pulses. The Advanced Test Accelerator (ATA) built at Livermore`s Site 300 produced 10,000 Ampere beams with pulse widths of 70 ns at energies approaching 50 MeV. Several other electron and ion induction accelerators have been fabricated at LLNL and LBNL. This paper reviews the principal diagnostics developed through efforts by scientists at both laboratories for measuring the current, position, energy, and emittance of beams generated by these high current, short pulse accelerators. Many of these diagnostics are closely related to those developed for other accelerators. However, the very fast and intense current pulses often require special diagnostic techniques and considerations. The physics and design of the more unique diagnostics developed for electron induction accelerators are presented and discussed in detail.

  19. KEK digital accelerator

    NASA Astrophysics Data System (ADS)

    Iwashita, T.; Adachi, T.; Takayama, K.; Leo, K. W.; Arai, T.; Arakida, Y.; Hashimoto, M.; Kadokura, E.; Kawai, M.; Kawakubo, T.; Kubo, Tomio; Koyama, K.; Nakanishi, H.; Okazaki, K.; Okamura, K.; Someya, H.; Takagi, A.; Tokuchi, A.; Wake, M.

    2011-07-01

    The High Energy Accelerator Research Organization KEK digital accelerator (KEK-DA) is a renovation of the KEK 500 MeV booster proton synchrotron, which was shut down in 2006. The existing 40 MeV drift tube linac and rf cavities have been replaced by an electron cyclotron resonance (ECR) ion source embedded in a 200 kV high-voltage terminal and induction acceleration cells, respectively. A DA is, in principle, capable of accelerating any species of ion in all possible charge states. The KEK-DA is characterized by specific accelerator components such as a permanent magnet X-band ECR ion source, a low-energy transport line, an electrostatic injection kicker, an extraction septum magnet operated in air, combined-function main magnets, and an induction acceleration system. The induction acceleration method, integrating modern pulse power technology and state-of-art digital control, is crucial for the rapid-cycle KEK-DA. The key issues of beam dynamics associated with low-energy injection of heavy ions are beam loss caused by electron capture and stripping as results of the interaction with residual gas molecules and the closed orbit distortion resulting from relatively high remanent fields in the bending magnets. Attractive applications of this accelerator in materials and biological sciences are discussed.

  20. Controllable Laser Ion Acceleration

    NASA Astrophysics Data System (ADS)

    Kawata, S.; Kamiyama, D.; Ohtake, Y.; Takano, M.; Barada, D.; Kong, Q.; Wang, P. X.; Gu, Y. J.; Wang, W. M.; Limpouch, J.; Andreev, A.; Bulanov, S. V.; Sheng, Z. M.; Klimo, O.; Psikal, J.; Ma, Y. Y.; Li, X. F.; Yu, Q. S.

    2016-02-01

    In this paper a future laser ion accelerator is discussed to make the laser-based ion accelerator compact and controllable. Especially a collimation device is focused in this paper. The future laser ion accelerator should have an ion source, ion collimators, ion beam bunchers, and ion post acceleration devices [Laser Therapy 22, 103(2013)]: the ion particle energy and the ion energy spectrum are controlled to meet requirements for a future compact laser ion accelerator for ion cancer therapy or for other purposes. The energy efficiency from the laser to ions is improved by using a solid target with a fine sub-wavelength structure or a near-critical density gas plasma. The ion beam collimation is performed by holes behind the solid target or a multi-layered solid target. The control of the ion energy spectrum and the ion particle energy, and the ion beam bunching would be successfully realized by a multistage laser-target interaction.