Science.gov

Sample records for accelerated aging experiments

  1. 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.

  2. Do US Black Women Experience Stress-Related Accelerated Biological Aging?

    PubMed Central

    Hicken, Margaret T.; Pearson, Jay A.; Seashols, Sarah J.; Brown, Kelly L.; Cruz, Tracey Dawson

    2010-01-01

    We hypothesize that black women experience accelerated biological aging in response to repeated or prolonged adaptation to subjective and objective stressors. Drawing on stress physiology and ethnographic, social science, and public health literature, we lay out the rationale for this hypothesis. We also perform a first population-based test of its plausibility, focusing on telomere length, a biomeasure of aging that may be shortened by stressors. Analyzing data from the Study of Women's Health Across the Nation (SWAN), we estimate that at ages 49–55, black women are 7.5 years biologically “older” than white women. Indicators of perceived stress and poverty account for 27% of this difference. Data limitations preclude assessing objective stressors and also result in imprecise estimates, limiting our ability to draw firm inferences. Further investigation of black-white differences in telomere length using large-population-based samples of broad age range and with detailed measures of environmental stressors is merited. PMID:20436780

  3. 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

  4. 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.

  5. 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.

  6. Cable aging phenomena under accelerated aging conditions

    SciTech Connect

    Behera, A.K.; Beck, C.E.; Alsammarae, A.

    1996-06-01

    A test program was conducted to determine the impact of accelerated (temperature and radiation) aging on the insulation of power cables. The intent was to develop a more realistic model for cable degradation mechanisms, and a more realistic technique for determining a cable`s qualified life. Samples of new cables and samples of cables obtained from an operating plant were subjected to a series of tests. The test showed that the order of imposing the harsh conditions, the presence of oxygen, and the use of a compressive measurement technique each had a significant impact on the results. This paper discusses the test methodology and test samples, the order of imposing artificial aging, and the results. Also presented are issues planned to be addressed in future testing.

  7. Non-accelerator experiments

    SciTech Connect

    Goldhaber, M.

    1986-01-01

    This report discusses several topics which can be investigated without the use of accelerators. Topics covered are: (1) proton decay, (2) atmospheric neutrinos, (3) neutrino detection, (4) muons from Cygnus X-3, and (5) the double-beta decay.

  8. FXR accelerator cavity impedance experiments

    SciTech Connect

    Avalle, C.A.

    1998-01-05

    One of the goals of the present Flash X-Ray (FXR) accelerator upgrade effort [1][2] at Lawrence Livermore National Laboratory (LLNL) is to reduce the cavity transverse impedance, since it has been shown that beam stability is significantly affected by this parameter [3]. Recently, we have evaluated various techniques and cell modifications to accomplish that, both through lab measurements and computer models. A spare cell, identical in every way to cells in the accelerator, was specially modified for the experiments. The impedance measurements were done without the beam, by applying twin-wire techniques. This report describes the results of these experiments and suggests possible cell modifications to improve their performance. The techniques and modifications which are suggested might also be applicable to AHF and DARHT-2 long-pulse accelerator development.

  9. 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.

  10. Accelerator physics experiments at Aladdin

    SciTech Connect

    Chattopadhyay, S.; Cornacchia, M.; Jackson, A.; Zisman, M.S.

    1985-07-01

    The Aladdin accelerator is a 1 GeV synchrotron light source located at the University of Wisconsin. The results of experimental studies of the Aladdin accelerator are described. The primary purpose of the experiments reported was to investigate reported anomalies in the behavior of the linear lattice, particularly in the vertical plane. A second goal was to estimate the ring broadband impedance. Experimental observations and interpretation of the linear properties of the Aladdin ring are described, including the beta function and dispersion measurements. Two experiments are described to measure the ring impedance, the first a measurement of the parasitic mode loss, and the second a measurement of the beam transfer function. Measurements of the longitudinal and transverse emittance at 100 and 200 MeV are described and compared with predictions. 10 refs., 24 figs., 2 tabs. (LEW)

  11. Testing of biomaterials, accelerated ageing.

    PubMed

    Prodinger, A; Krausler, S; Schima, H; Thoma, H; Wolner, E; Schneider, W

    1985-01-01

    The residual elongation is a critical property of materials used for manufacturing diaphragms of artificial hearts. It is therefore important to check goods received or to control manufactured diaphragms, whether their creep properties are within the required limits. Ordinary creep tests take at least several months, while the release of goods received or diaphragms manufactured should be possible within a few days. Acceleration of the creep test by increasing the test temperature permits an estimation whether the creep properties of a material are within the required limits within a week. PMID:3870605

  12. Deuterium accelerator experiments for APT.

    SciTech Connect

    Causey, Rion A. (Sandia National Laboratories, Livermore, CA); Hertz, Kristin L. (Sandia National Laboratories, Livermore, CA); Cowgill, Donald F. (Sandia National Laboratories, Livermore, CA)

    2005-08-01

    Sandia National Laboratories in California initiated an experimental program to determine whether tritium retention in the tube walls and permeation through the tubes into the surrounding coolant water would be a problem for the Accelerator Production of Tritium (APT), and to find ways to mitigate the problem, if it existed. Significant holdup in the tube walls would limit the ability of APT to meet its production goals, and high levels of permeation would require a costly cleanup system for the cooling water. To simulate tritium implantation, a 200 keV accelerator was used to implant deuterium into Al 6061-T and SS3 16L samples at temperatures and particle fluxes appropriate for APT, for times varying between one week and five months. The implanted samples were characterized to determine the deuterium retention and Permeation. During the implantation, the D(d,p)T nuclear reaction was used to monitor the build-up of deuterium in the implant region of the samples. These experiments increased in sophistication, from mono-energetic deuteron implants to multi-energetic deuteron and proton implants, to more accurately reproduce the conditions expected in APT. Micron-thick copper, nickel, and anodized aluminum coatings were applied to the front surface of the samples (inside of the APT walls) in an attempt to lower retention and permeation. The reduction in both retention and permeation produced by the nickel coatings, and the ability to apply them to the inside of the APT tubes, indicate that both nickel-coated Al 6061-T6 and nickel-coated SS3 16L tubes would be effective for use in APT. The results of this work were submitted to the Accelerator Production of Tritium project in document number TPO-E29-Z-TNS-X-00050, APT-MP-01-17.

  13. 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

  14. Is schizophrenia a syndrome of accelerated aging?

    PubMed

    Kirkpatrick, Brian; Messias, Erick; Harvey, Philip D; Fernandez-Egea, Emilio; Bowie, Christopher R

    2008-11-01

    Schizophrenia is associated with a number of anatomical and physiological abnormalities outside of the brain, as well as with a decrease in average life span estimated at 20% in the United States. Some studies suggest that this increased mortality is not entirely due to associated causes such as suicide and the use of psychotropic medications. In this article, in order to focus greater attention on the increased mortality associated with schizophrenia, we present a special case of the hypothesis that physiological abnormalities associated with schizophrenia make a contribution to the increased mortality of schizophrenia: specifically, the hypothesis that schizophrenia is a syndrome of accelerated aging. Evidence consistent with this hypothesis comes from several areas. The biological plausibility of the hypothesis is supported by the existence of established syndromes of accelerated aging and by the sharing of risk factors between schizophrenia and other age-related conditions. We propose methods for testing the hypothesis. PMID:18156637

  15. Accelerated aging of wood-composite members

    SciTech Connect

    Sonti, S.S.; GangaRao, H.V.S.; Talakanti, D.R.

    1996-12-31

    This paper discusses the longterm performance of various adhesives under accelerated aging conditions, where the intended application of the adhesives is bonding wood member to composite fabric wraps. Northern Red Oak was used as the core and two types of composite fabrics were used (glass and carbon) as external reinforcements. The adhesives used for bonding include: Epoxy, Polyurethane, Isopolyester, Resorcinol Formaldehyde, and Phenolic based Resorcinol Formaldehyde. Results from the shear strength evaluations show that a primer/resin combination provided a better bond compared to the bond developed by resin system only. Also, it was observed that phenolic-based resins had higher retention of shear strength after being subjected to aging conditions.

  16. Experiment specific processing of residual acceleration data

    NASA Technical Reports Server (NTRS)

    Rogers, Melissa J. B.; Alexander, J. I. D.

    1992-01-01

    To date, most Spacelab residual acceleration data collection projects have resulted in data bases that are overwhelming to the investigator of low-gravity experiments. This paper introduces a simple passive accelerometer system to measure low-frequency accelerations. Model responses for experiments using actual acceleration data are produced and correlations are made between experiment response and the accelerometer time history in order to test the idea that recorded acceleration data and experimental responses can be usefully correlated. Spacelab 3 accelerometer data are used as input to a variety of experiment models, and sensitivity limits are obtained for particular experiment classes. The modeling results are being used to create experiment-specific residual acceleration data processing schemes for interested investigators.

  17. Space Experiments with Particle Accelerators (SEPAC)

    NASA Technical Reports Server (NTRS)

    Roberts, W. T.

    1985-01-01

    The space experiments with particle accelerators (SEPAC) instruments consist of an electron accelerator, a plasma accelerator, a neutral gas (N2) release device, particle and field diagnostic instruments, and a low light level television system. These instruments are used to accomplish multiple experiments: to study beam particle interactions and other plasma processes; as probes to investigate magnetospheric processes; and as perturbation devices to study energy coupling mechanisms in the magnetosphere, ionosphere, and upper atmosphere.

  18. Inverse Cerenkov laser acceleration experiment at ATF

    NASA Astrophysics Data System (ADS)

    Wang, X. J.; Pogorelsky, I.; Fernow, R.; Kusche, K. P.; Liu, Y.; Kimura, W. D.; Kim, G. H.; Romea, R. D.; Steinhauer, L. C.

    Inverse Cerenkov laser acceleration was demonstrated using an axicon optical system at the Brookhaven Accelerator Test Facility (ATF). The ATF S-band linac and a high power 10.6 MICROMETERSCO2 laser were used for the experiment. Experimental arrangement and the laser and the electron beams synchronization are discussed. The electrons were accelerated more than 0.7 MeV for a 34 MW CO2 laser power. More than 3.7 MeV acceleration was measured with 0.7 GW CO2 laser power, which is more than 20 times of the previous ICA experiment. The experimental results are compared with computer program TRANSPORT simulations.

  19. Insights into accelerated aging of SSL luminaires

    DOE PAGESBeta

    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

  20. 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.

  1. 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.

  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. 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.

  4. 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)

  5. 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. PMID:23372574

  6. Accelerated Aging of Polymer Composite Bridge Materials

    SciTech Connect

    J. G. Rodriguez; L. G. Blackwood; L. L. Torres; N. M. Carlson; T. S. Yoder

    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.

  7. Premature and accelerated aging: HIV or HAART?

    PubMed Central

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

    2013-01-01

    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. PMID:23372574

  8. Laboratory Reconnection Experiments - heating and particle acceleration

    NASA Astrophysics Data System (ADS)

    Ono, Yasushi

    Recent laboratory merging/ reconnection experiments have solved a number of key physics of magnetic reconnection: 1) reconnection heating/ acceleration, 2) fast reconnection mechanisms, 3) plasmoid reconnection, 4) non-steady reconnection and 5) non-thermal particle acceleration using new kinetic interpretations. Especially, significant ion temperatures 1.2keV were documented in the world-largest tokamak merging experiment: MAST after detailed 2D elucidation of ion and electron heating characteristics in TS-3 and 4 merging experiments. The measured 2D contours of ion and electron temperatures in TS-3, 4 and MAST reveal ion heating in the downstream by reconnection outflow and electron heating around the X-point by ohmic heating of current sheet. Their detailed heating mechanisms were further investigated by comparing those results with particle simulations developed by NIFS. The ion acceleration mechanism is mostly parallel acceleration by reconnection electric field and partly perpendicular acceleration by electrostatic potential. The fast shock and ion viscosity are the major dumping (heating) mechanisms for the accelerated ions. We successfully applied the reconnection heating - typically 10-50MW to the high-beta spherical tokamak formation and heating. This paper will review major progresses in those international and interdisciplinary merging tokamak experiments.

  9. 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.

  10. Accelerator/Experiment Operations - FY 2010

    SciTech Connect

    Adamson, M.; Appel, J.A.; Casarsa, M.; Coleman, R.; Denisov, D.; Dixon, R.; Escobar, C.; Ginther, G.; Gruenendahl, S.; Harris, D.; Henderson, S.; /Fermilab

    2010-11-01

    This Technical Memorandum (TM) summarizes the Fermilab accelerator and accelerator experiment operations for FY 2010. It is one of a series of annual publications intended to gather information in one place. In this case, the information concerns the FY 2010 Run II at the Tevatron Collider, the MINOS and MINER?A experiments using the Main Injector Neutrino Beam (NuMI), the MiniBooNE experiment running in the Booster Neutrino Beam (BNB), and the Meson Test Beam (MTest) activities in the 120 GeV external Switchyard beam (SY120). Each section was prepared by the relevant authors, and was somewhat edited for inclusion in this summary.

  11. Accelerator/Experiment Operations - FY 2011

    SciTech Connect

    Adamson, P.; Bernardi, G.; Casarsa, M.; Coleman, R.; Denisov, D.; Dixon, R.; Ginther, G.; Gruenendahl, S.; Hahn, S.; Harris, D.; Henderson, S.

    2011-11-01

    This Technical Memorandum (TM) summarizes the Fermilab accelerator and accelerator experiment operations for FY 2011. It is one of a series of annual publications intended to gather information in one place. In this case, the information concerns the FY 2011 Run II at the Tevatron Collider, the MINOS and MINERvA experiments using the Main Injector Neutrino Beam (NuMI), the MiniBooNE experiment running in the Booster Neutrino Beam (BNB), and the Meson Test Beam (MTest) activities in the 120 GeV external Switchyard beam (SY120).

  12. Accelerator/Experiment operations - FY 2004

    SciTech Connect

    Bromberg, C.; Conrad, J.; Denisov, D.; Holmes, S.; Louis, W.; Meyer, A.; Moore, Craig D.; Raja, R.; Ramberg, E.; Roser, R.; /Fermilab

    2004-12-01

    This Technical Memorandum (TM) summarizes the accelerator and experiment operations for FY 2004. It is one of a series of annual publications intended to gather information in one place. In this case, the information concerns the FY 2004 Run II at the Tevatron Collider, the MiniBooNE neutrino experiment, and SY 120 activities.

  13. Accelerated Application Development: The ORNL Titan Experience

    SciTech Connect

    Joubert, Wayne; Archibald, Richard K.; Berrill, Mark A.; Brown, W. Michael; Eisenbach, Markus; Grout, Ray; Larkin, Jeff; Levesque, John; Messer, Bronson; Norman, Matthew R.; Philip, Bobby; Sankaran, Ramanan; Tharrington, Arnold N.; Turner, John A.

    2015-05-09

    The use of computational accelerators such as NVIDIA GPUs and Intel Xeon Phi processors is now widespread in the high performance computing community, with many applications delivering impressive performance gains. However, programming these systems for high performance, performance portability and software maintainability has been a challenge. In this paper we discuss experiences porting applications to the Titan system. Titan, which began planning in 2009 and was deployed for general use in 2013, was the first multi-petaflop system based on accelerator hardware. To ready applications for accelerated computing, a preparedness effort was undertaken prior to delivery of Titan. In this paper we report experiences and lessons learned from this process and describe how users are currently making use of computational accelerators on Titan.

  14. Accelerated Application Development: The ORNL Titan Experience

    DOE PAGESBeta

    Joubert, Wayne; Archibald, Richard K.; Berrill, Mark A.; Brown, W. Michael; Eisenbach, Markus; Grout, Ray; Larkin, Jeff; Levesque, John; Messer, Bronson; Norman, Matthew R.; et al

    2015-05-09

    The use of computational accelerators such as NVIDIA GPUs and Intel Xeon Phi processors is now widespread in the high performance computing community, with many applications delivering impressive performance gains. However, programming these systems for high performance, performance portability and software maintainability has been a challenge. In this paper we discuss experiences porting applications to the Titan system. Titan, which began planning in 2009 and was deployed for general use in 2013, was the first multi-petaflop system based on accelerator hardware. To ready applications for accelerated computing, a preparedness effort was undertaken prior to delivery of Titan. In this papermore » we report experiences and lessons learned from this process and describe how users are currently making use of computational accelerators on Titan.« less

  15. Inverse Cerenkov laser acceleration experiment at ATF

    SciTech Connect

    Wang, X.J.; Pogorelsky, I.; Fernow, R.; Kusche, K.P.; Liu, Y.; Kimura, W.D.; Kim, G.H.; Romea, R.D.; Steinhauer, L.C.

    1994-09-01

    Inverse Cerenkov laser acceleration was demonstrated using an axicon optical system at the Brookhaven Accelerator Test Facility (ATF). The ATF S-band linac and a high power 10.6 {mu}m CO{sub 2} laser were used for the experiment. Experimental arrangement and the laser and the electron beams synchronization are discussed. The electrons were accelerated more than 0.7 MeV for a 34 MW CO{sub 2} laser power. More than 3.7 MeV acceleration was measured with 0.7 GW CO{sub 2} laser power, which is more than 20 times of the previous ICA experiment. The experimental results are compared with computer program TRANSPORT simulations.

  16. Space experiments with particle accelerators: SEPAC

    NASA Technical Reports Server (NTRS)

    Roberts, B.

    1986-01-01

    The SEPAC instruments consist of an electron accelerator, a plasma accelerator, a neutral gas (N2) release device, particle and field diagnostic instruments, and a low light level television system. These instruments are used to accomplish multiple experiments: to study beam-particle interactions and other plasma processes; as probes to investigate magnetospheric processes; and as perturbation devices to study energy coupling mechanisms in the magnetosphere, ionosphere, and upper atmosphere.

  17. Age Differences in Mystical Experience.

    ERIC Educational Resources Information Center

    Levin, Jeffrey S.

    1993-01-01

    Examined age differences in mystical experiences. According to 1988 General Social Survey (n=1,481) mystical experiences were somewhat more common in 1988 than in 1973, and deja vu, clairvoyance, and composite mysticism scores had increased with successively younger age cohorts. Private and subjective religiosity were positively related to overall…

  18. The FRC Acceleration Space Thruster (FAST) Experiment

    NASA Technical Reports Server (NTRS)

    Martin, Adam; Eskridge, Richard; Houts, Mike; Slough, John; Rodgers, Stephen L. (Technical Monitor)

    2002-01-01

    The objective of the FRC (Field Reversed Configuration) Acceleration Space Thruster (FAST) Experiment is to investigate the use of a repetitive FRC source as a thruster, specifically for an NEP (nuclear electric propulsion) system. The Field Reversed Configuration is a plasmoid with a closed poloidal field line structure, and has been extensively studied as a fusion reactor core. An FRC thruster works by repetitively producing FRCs and accelerating them to high velocity. An FRC thruster should be capable of I(sub sp)'s in the range of 5,000 - 25,000 seconds and efficiencies in the range of 60 - 80 %. In addition, they can have thrust densities as high as 10(exp 6) N/m2, and as they are inductively formed, they do not suffer from electrode erosion. The jet-power should be scalable from the low to the high power regime. The FAST experiment consists of a theta-pinch formation chamber, followed by an acceleration stage. Initially, we will produce and accelerate single FRCs. The initial focus of the experiment will be on the ionization, formation and acceleration of a single plasmoid, so as to determine the likely efficiency and I(sub sp). Subsequently, we will modify the device for repetitive burst-mode operation (5-10 shots). A variety of diagnostics are or will be available for this work, including a HeNe interferometer, high-speed cameras, and a Thomson-scattering system. The status of the experiment will be described.

  19. Accelerator/Experiment Operations - FY 2007

    SciTech Connect

    Brice, S.; Buchanan, N.; Coleman, R.; Convery, M.; Denisov, D.; Ginther, G.; Habig, A.; Holmes, S.; Kissel, W.; Lee, W.; Nakaya, T.; /Fermilab

    2007-10-01

    This Technical Memorandum (TM) summarizes the Fermilab accelerator and accelerator experiment operations for FY 2007. It is one of a series of annual publications intended to gather information in one place. In this case, the information concerns the FY 2007 Run II at the Tevatron Collider, the MiniBooNE and SciBooNE experiments running in the Booster Neutrino Beam (BNB), MINOS using the Main Injector Neutrino Beam (NuMI), and the Meson Test Beam (MTest) activities in the 120 GeV external Switchyard beam (SY120). Each section was prepared by the relevant authors, and was somewhat edited for inclusion in this summary.

  20. Accelerator/Experiment Operations - FY 2008

    SciTech Connect

    Brice, Stephen J.; Buehler, M.; Casarsa, M.; Coleman, R.; Denisov, D.; Ginther, G.; Grinstein, S.; Habig, A.; Holmes, S.; Hylen, J.; Kissel, W.; /Fermilab

    2008-10-01

    This Technical Memorandum (TM) summarizes the Fermilab accelerator and accelerator experiment operations for FY 2008. It is one of a series of annual publications intended to gather information in one place. In this case, the information concerns the FY 2008 Run II at the Tevatron Collider, MINOS using the Main Injector Neutrino Beam (NuMI), the MiniBooNE and SciBooNE experiments running in the Booster Neutrino Beam (BNB), and the Meson Test Beam (MTest) activities in the 120 GeV external Switchyard beam (SY120).

  1. Accelerator/Experiment Operations - FY 2009

    SciTech Connect

    Andrews, M.N; Appel, J.A.; Brice, S.; Casarsa, M.; Coleman, R.; Denisov, d.; Ginther, G.; Gruenendahl, S.; Holmes, S.; Kissel, W.; Lee, W.M.; /Fermilab

    2009-10-01

    This Technical Memorandum (TM) summarizes the Fermilab accelerator and accelerator experiment operations for FY 2009. It is one of a series of annual publications intended to gather information in one place. In this case, the information concerns the FY 2009 Run II at the Tevatron Collider, MINOS using the Main Injector Neutrino Beam (NuMI), the MiniBooNE experiment running in the Booster Neutrino Beam (BNB), and the Meson Test Beam (MTest) activities in the 120 GeV external Switchyard beam (SY120). Each section was prepared by the relevant authors, and was somewhat edited for inclusion in this summary.

  2. Accelerator/Experiment operations - FY 2006

    SciTech Connect

    Brice, S.; Conrad, J.; Denisov, D.; Ginther, G.; Holmes, S.; James, C.; Lee, W.; Louis, W.; Moore, C.; Plunkett, R.; Raja, R.; /Fermilab

    2006-10-01

    This Technical Memorandum (TM) summarizes the Fermilab accelerator and experiment operations for FY 2006. It is one of a series of annual publications intended to gather information in one place. In this case, the information concerns the FY 2006 Run II at the Tevatron Collider, the MiniBooNE experiments running in the Booster Neutrino Beam in neutrino and antineutrino modes, MINOS using the Main Injector Neutrino Beam (NuMI), and SY 120 activities.

  3. Diagnostics for advanced laser acceleration experiments

    SciTech Connect

    Misuri, Alessio

    2002-06-01

    The first proposal for plasma based accelerators was suggested by 1979 by Tajima and Dawson. Since then there has been a tremendous progress both theoretically and experimentally. The theoretical progress is particularly due to the growing interest in the subject and to the development of more accurate numerical codes for the plasma simulations (especially particle-in-cell codes). The experimental progress follows from the development of multi-terawatt laser systems based on the chirped-pulse amplification technique. These efforts have produced results in several experiments world-wide, with the detection of accelerated electrons of tens of MeV. The peculiarity of these advanced accelerators is their ability to sustain extremely large acceleration gradients. In the conventional radio frequency linear accelerators (RF linacs) the acceleration gradients are limited roughly to 100 MV/m; this is partially due to breakdown which occurs on the walls of the structure. The electrical breakdown is originated by the emission of the electrons from the walls of the cavity. The electrons cause an avalanche breakdown when they reach other metal parts of the RF linacs structure.

  4. Space Experiments with Particle Accelerators (SEPAC)

    NASA Technical Reports Server (NTRS)

    Obayashi, Tatsuzo

    1988-01-01

    The purpose of Space Experiments with Particle Accelerators (SEPAC) on the Atmospheric Laboratory for Applications and Science (ATLAS 1) mission, is to carry out active and interactive experiments on and in the earth's ionosphere, atmosphere, and magnetosphere. The instruments to be used are an electron beam accelerator (EBA), plasma contactor, and associated instruments the purpose of which is to perform diagnostic, monitoring, and general data taking functions. Four major classes of investigations are to be performed by SEPAC. They are: beam plasma physics, beam-atmosphere interactions, the use of modulated electron beams as transmitting antennas, and the use of electron beams for remote sensing of electric and magnetic fields. The first class consists mainly of onboard plasma physics experiments to measure the effects of phenomena in the vicinity of the shuttle. The last three are concerned with remote effects and are supported by other ATLAS 1 investigations as well as by ground-based observations.

  5. Accelerator/Experiment Operations - FY 2015

    SciTech Connect

    Czarapata, P.

    2015-10-01

    This Technical Memorandum summarizes the Fermilab accelerator and experiment operations for FY 2015. It is one of a series of annual publications intended to gather information in one place. In this case, the information concerns the FY 2015 NOvA, MINOS+ and MINERvA experiments using the Main Injector Neutrino Beam (NuMI), the activities in the SciBooNE Hall using the Booster Neutrino Beam (BNB), and the SeaQuest experiment and Meson Test Beam (MTest) activities in the 120 GeV external Switchyard beam (SY120).

  6. Space experiments with particle accelerators. [Spacelab

    NASA Technical Reports Server (NTRS)

    Obayashi, T.

    1981-01-01

    The purpose of space experiments with particle accelerators (SEPAC) is to carry out active and interactive experiments on and in the Earth's ionosphere and magnetosphere. It is also intended to make an initial performance test for an overall program of Spacelab/SEPAC experiments. The instruments to be used are an electron beam accelerator, magnetoplasma dynamic arcjet, and associated diagnostic equipment. The accelerators are installed on the pallet, with monitoring and diagnostic observations being made by the gas plume release, beam-monitor TV, and particle-wave measuring instruments also mounted on the pallet. Command and display systems are installed in the module. Three major classes of investigations to be performed are vehicle charge neutralization, beam plasma physics, and beam atmosphere interactions. The first two are mainly onboard plasma physics experiments to measure the effect of phenomena in the vicinity of Spacelab. The last one is concerned with atmospheric modification and is supported by other Spacelab 1 investigations as well as by ground-based, remote sensing observations.

  7. Orbital Acceleration Research Experiment: Calibration Measurements

    NASA Technical Reports Server (NTRS)

    Blanchard, Robert C.; Nicholson, John Y.; Ritter, James R.; Larman, Kevin T.

    1995-01-01

    The Orbital Acceleration Research Experiment (OARE), which has flown on STS-40, STS-50, and STS-58, contains a three-axis accelerometer with a single, nonpendulous, electrostatically suspended proofmass, which can resolve accelerations to the 10(sub -9) g level. The experiment also contains a full calibration station to permit in situ bias and scale-factor calibration. This on-orbit calibration capability eliminates the large uncertainty of ground-based calibrations encountered with accelerometers flown in the past on the Orbiter, and thus provides absolute acceleration measurement accuracy heretofore unachievable. This is the first time accelerometer scale-factor measurements have been performed on orbit. A detailed analysis of the calibration process is given, along with results of the calibration factors from the on-orbit OARE flight measurements on STS-58. In addition, the analysis of OARE flight-maneuver data used to validate the scale-factor measurements in the sensor's most sensitive range are also presented. Estimates on calibration uncertainties are discussed. These uncertainty estimates provides bounds on the STS-58 absolute acceleration measurements for future applications.

  8. Space Experiments with Particle Accelerators: SEPAC

    NASA Technical Reports Server (NTRS)

    Burch, J. L.; Roberts, W. T.; Taylor, W. W. L.; Kawashima, N.; Marshall, J. A.; Moses, S. L.; Neubert, T.; Mende, S. B.; Choueiri, E. Y.

    1994-01-01

    The Space Experiments with Particle Accelerators (SEPAC), which flew on the Atmospheric Laboratory for Applications and Science (ATLAS) 1 mission, used new techniques to study natural phenomena in the Earth's upper atmosphere, ionosphere and magnetosphere by introducing energetic perturbations into the system from a high power electron beam with known characteristics. Properties of auroras were studied by directing the electron beam into the upper atmosphere while making measurements of optical emissions. Studies were also performed of the critical ionization velocity phenomenon.

  9. 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.

  10. 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.

  11. The Argon Geochronology Experiment (AGE)

    NASA Technical Reports Server (NTRS)

    Swindle, T. D.; Bode, R.; Fennema, A.; Chutjian, A.; MacAskill, J. A.; Darrach, M. R.; Clegg, S. M.; Wiens, R. C.; Cremers, D.

    2006-01-01

    This viewgraph presentation reviews the Argon Geochronology Experiment (AGE). Potassium-Argon dating is shown along with cosmic ray dating exposure. The contents include a flow diagram of the Argon Geochronology Experiment, and schematic diagrams of the mass spectrometer vacuum system, sample manipulation mechanism, mineral heater oven, and the quadrupole ion trap mass spectrometer. The Laser-Induced Breakdown Spectroscopy (LIBS) Operation with elemental abundances is also described.

  12. Accelerator-based neutrino oscillation experiments

    SciTech Connect

    Harris, Deborah A.; /Fermilab

    2007-12-01

    Neutrino oscillations were first discovered by experiments looking at neutrinos coming from extra-terrestrial sources, namely the sun and the atmosphere, but we will be depending on earth-based sources to take many of the next steps in this field. This article describes what has been learned so far from accelerator-based neutrino oscillation experiments, and then describe very generally what the next accelerator-based steps are. In section 2 the article discusses how one uses an accelerator to make a neutrino beam, in particular, one made from decays in flight of charged pions. There are several different neutrino detection methods currently in use, or under development. In section 3 these are presented, with a description of the general concept, an example of such a detector, and then a brief discussion of the outstanding issues associated with this detection technique. Finally, section 4 describes how the measurements of oscillation probabilities are made. This includes a description of the near detector technique and how it can be used to make the most precise measurements of neutrino oscillations.

  13. Magnetically accelerated foils for shock wave experiments

    NASA Astrophysics Data System (ADS)

    Neff, Stephan; Ford, Jessica; Martinez, David; Plechaty, Christopher; Wright, Sandra; Presura, Radu

    2008-04-01

    The interaction of shock waves with inhomogeneous media is important in many astrophysical problems, e.g. the role of shock compression in star formation. Using scaled experiments with inhomogeneous foam targets makes it possible to study relevant physics in the laboratory, to better understand the mechanisms of shock compression and to benchmark astrophysical simulation codes. Experiments with flyer-generated shock waves have been performed on the Z machine in Sandia. The Zebra accelerator at the Nevada Terawatt Facility (NTF) allows for complementary experiments with high repetition rate. First experiments on Zebra demonstrated flyer acceleration to sufficiently high velocities (around 2 km/s) and that laser shadowgraphy can image sound fronts in transparent targets. Based on this, we designed an optimized setup to improve the flyer parameters (higher speed and mass) to create shock waves in transparent media. Once x-ray backlighting with the Leopard laser at NTF is operational, we will switch to foam targets with parameters relevant for laboratory astrophysics.

  14. The LHCf experiment at the LHC accelerator

    SciTech Connect

    Bonechi, L.; Adriani, O.; Bongi, M.; D'Alessandro, R.; Papini, P.; Castellini, G.; Faus, A.; Velasco, J.; Haguenauer, M.; Itow, Y.; Mase, T.; Masuda, K.; Matsubara, Y.; Matsumoto, H.; Menjo, H.; Muraki, Y.; Sako, T.; Tanaka, K.; Watanabe, H.; Kasahara, K.

    2006-10-27

    The claimed discovery of atmospheric shower induced by cosmic-ray with energy beyond the GZK cutoff by the AGASA experiment in 1994-1995, although not confirmed by other important experiments like Fly's Eye and Hi-Res, together with the poor knowledge of the composition of cosmic rays around and beyond the Knee region, have highlighted the necessity of new experiments that should increase our present knowledge of HECR and UHECR. For this reason big efforts have been addressed to the development of new experiments, like Auger, TA and EUSO, for a systematic study of the UHE atmospheric showers with increased capabilities with respect to the previous experiments. Moreover complementary experiments should allow a precise calibration of the methods used for the reconstruction of cosmic-ray showers in atmosphere. Their aim is the measurement of quantities that are used in these procedures and that are not yet precisely known. Under this perspective the LHCf experiment is a compact experiment which has been proposed for the study of neutral pion and gamma production at high energy in proton-proton interaction in the very forward region of the LHC accelerator. It will help calibrating the algorithms that are used to reconstruct the atmospheric shower events for energy beyond the Knee. The LHCf apparatus and the results of the first beam test, held in 2004, are shortly discussed in this work.

  15. 'Accelerated aging': a primrose path to insight?

    PubMed

    Miller, Richard A

    2004-04-01

    Organism envy afflicts most researchers who work on aging in mice; how frustrating it is to see the worm and fly biologists nail down milestone after milestone, citation after citation! Surely genetic trickery can produce mice that age in a comparable jiffy? Alas, our near-total ignorance of what times the aging process makes it hard to guess what genes to tweak, if indeed aging can be mimicked a presto. Building a case that a given short-lived mutant ages quickly is a steep and thorny path, requiring more than just plucking a symptom here and there from a list of things that sometimes go wrong in old people or old mice. The hallmark of aging is that a lot goes wrong more or less at the same time, in 2-year-old mice, 10-year-old dogs and 70-year-old people. Finding ways to damage one or two systems in a 6-week or 6-month-old mouse is not too hard to do, but the implications of such studies for improved understanding of aging per se are at best indirect and at worst imaginary and distracting. PMID:15038817

  16. Choosing experiments to accelerate collective discovery

    SciTech Connect

    Rzhetsky, Andrey; Foster, Jacob G.; Foster, Ian T.; Evans, James A.

    2015-11-24

    Scientists perform a tiny subset of all possible experiments. What characterizes the experiments they choose? What are the consequences of those choices for the pace of scientific discovery? We model scientific knowledge as a network and science as a sequence of experiments designed to gradually uncover it. By analyzing millions of biomedical articles published over 30 y, we find that biomedical scientists pursue conservative research strategies exploring the local neighborhood of central, important molecules. Although such strategies probably serve scientific careers, we show that they slow scientific advance, especially in mature fields, where more risk and less redundant experimentation would accelerate discovery of the network. Lastly, we also consider institutional arrangements that could help science pursue these more efficient strategies.

  17. Choosing experiments to accelerate collective discovery

    DOE PAGESBeta

    Rzhetsky, Andrey; Foster, Jacob G.; Foster, Ian T.; Evans, James A.

    2015-11-24

    Scientists perform a tiny subset of all possible experiments. What characterizes the experiments they choose? What are the consequences of those choices for the pace of scientific discovery? We model scientific knowledge as a network and science as a sequence of experiments designed to gradually uncover it. By analyzing millions of biomedical articles published over 30 y, we find that biomedical scientists pursue conservative research strategies exploring the local neighborhood of central, important molecules. Although such strategies probably serve scientific careers, we show that they slow scientific advance, especially in mature fields, where more risk and less redundant experimentation wouldmore » accelerate discovery of the network. Lastly, we also consider institutional arrangements that could help science pursue these more efficient strategies.« less

  18. 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

  19. Accelerated food source location in aging Drosophila.

    PubMed

    Egenriether, Sada M; Chow, Eileen S; Krauth, Nathalie; Giebultowicz, Jadwiga M

    2015-10-01

    Adequate energy stores are essential for survival, and sophisticated neuroendocrine mechanisms evolved to stimulate foraging in response to nutrient deprivation. Food search behavior is usually investigated in young animals, and it is not known how aging alters this behavior. To address this question in Drosophila melanogaster, we compared the ability to locate food by olfaction in young and old flies using a food-filled trap. As aging is associated with a decline in motor functions, learning, and memory, we expected that aged flies would take longer to enter the food trap than their young counterparts. Surprisingly, old flies located food with significantly shorter latency than young ones. Robust food search behavior was associated with significantly lower fat reserves and lower starvation resistance in old flies. Food-finding latency (FFL) was shortened in young wild-type flies that were starved until their fat was depleted but also in heterozygous chico mutants with reduced insulin receptor activity and higher fat deposits. Conversely, food trap entry was delayed in old flies with increased insulin signaling. Our results suggest that the difference in FFL between young and old flies is linked to age-dependent differences in metabolic status and may be mediated by reduced insulin signaling. PMID:26102220

  20. Space Experiments with Particle Accelerators (SEPAC)

    NASA Technical Reports Server (NTRS)

    Obayashi, T.; Kawashima, N.; Kuriki, K.; Nagatomo, M.; Ninomiya, K.; Sasaki, S.; Ushirokawa, A.; Kudo, I.; Ejiri, M.; Roberts, W. T.

    1982-01-01

    Plans for SEPAC, an instrument array to be used on Spacelab 1 to study vehicle charging and neutralization, beam-plasma interaction in space, beam-atmospheric interaction exciting artificial aurora and airglow, and the electromagnetic-field configuration of the magnetosphere, are presented. The hardware, consisting of electron beam accelerator, magnetoplasma arcjet, neutral-gas plume generator, power supply, diagnostic package (photometer, plasma probes, particle analyzers, and plasma-wave package), TV monitor, and control and data-management unit, is described. The individual SEPAC experiments, the typical operational sequence, and the general outline of the SEPAC follow-on mission are discussed. Some of the experiments are to be joint ventures with AEPI (INS 003) and will be monitored by low-light-level TV.

  1. Magnetically accelerated foils for shock wave experiments

    NASA Astrophysics Data System (ADS)

    Neff, S.; Ford, J.; Wright, S.; Martinez, D.; Plechaty, C.; Presura, R.

    2009-08-01

    Many astrophysical phenomena involve the interaction of a shock wave with an inhomogeneous background medium. Using scaled experiments with inhomogeneous foam targets makes it possible to study relevant physics in the laboratory to better understand the mechanisms of shock compression and to benchmark astrophysical simulation codes. First experiments on Zebra at the Nevada Terawatt Facility (NTF) have demonstrated flyer acceleration to sufficiently high velocities (up to 5 km/s) and that laser shadowgraphy can image sound fronts in transparent targets. Based on this, we designed an optimized setup to improve the flyer parameters (higher speed and mass) to create shock waves in transparent media. Once x-ray backlighting with the Leopard laser at NTF is operational, we will switch to foam targets with parameters relevant for laboratory astrophysics.

  2. Pulsed power accelerator for material physics experiments

    NASA Astrophysics Data System (ADS)

    Reisman, D. B.; Stoltzfus, B. S.; Stygar, W. A.; Austin, K. N.; Waisman, E. M.; Hickman, R. J.; Davis, J.-P.; Haill, T. A.; Knudson, M. D.; Seagle, C. T.; Brown, J. L.; Goerz, D. A.; Spielman, R. B.; Goldlust, J. A.; Cravey, W. R.

    2015-09-01

    We have developed the design of Thor: a pulsed power accelerator that delivers a precisely shaped current pulse with a peak value as high as 7 MA to a strip-line load. The peak magnetic pressure achieved within a 1-cm-wide load is as high as 100 GPa. Thor is powered by as many as 288 decoupled and transit-time isolated bricks. Each brick consists of a single switch and two capacitors connected electrically in series. The bricks can be individually triggered to achieve a high degree of current pulse tailoring. Because the accelerator is impedance matched throughout, capacitor energy is delivered to the strip-line load with an efficiency as high as 50%. We used an iterative finite element method (FEM), circuit, and magnetohydrodynamic simulations to develop an optimized accelerator design. When powered by 96 bricks, Thor delivers as much as 4.1 MA to a load, and achieves peak magnetic pressures as high as 65 GPa. When powered by 288 bricks, Thor delivers as much as 6.9 MA to a load, and achieves magnetic pressures as high as 170 GPa. We have developed an algebraic calculational procedure that uses the single brick basis function to determine the brick-triggering sequence necessary to generate a highly tailored current pulse time history for shockless loading of samples. Thor will drive a wide variety of magnetically driven shockless ramp compression, shockless flyer plate, shock-ramp, equation of state, material strength, phase transition, and other advanced material physics experiments.

  3. Space Experiments with Particle Accelerators (SEPAC)

    NASA Technical Reports Server (NTRS)

    Taylor, William W. L.

    1994-01-01

    The scientific emphasis of this contract has been on the physics of beam ionosphere interactions, in particular, what are the plasma wave levels stimulated by the Space Experiments with Particle Accelerators (SEPAC) electron beam as it is ejected from the Electron Beam Accelerator (EBA) and passes into and through the ionosphere. There were two different phenomena expected. The first was generation of plasma waves by the interaction of the DC component of the beam with the plasma of the ionosphere, by wave particle interactions. The second was the generation of waves at the pulsing frequency of the beam (AC component). This is referred to as using the beam as a virtual antenna, because the beam of electrons is a coherent electrical current confined to move along the earth's magnetic field. As in a physical antenna, a conductor at a radio or TV station, the beam virtual antenna radiates electromagnetic waves at the frequency of the current variations. These two phenomena were investigated during the period of this contract.

  4. 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.

  5. Disk Acceleration Experiment Utilizing Minimal Material (DAXUMM)

    NASA Astrophysics Data System (ADS)

    Biss, Matthew; Lorenz, Thomas; Sutherland, Gerrit

    2015-06-01

    A venture between the US Army Research Laboratory (ARL) and Lawrence Livermore National Laboratory (LLNL) is currently underway in an effort to characterize novel energetic material performance properties using a single, high-precision, gram-range charge. A nearly all-inclusive characterization experiment is proposed by combing LLNL's disk acceleration experiment (DAX) with the ARL explosive evaluation utilizing minimal material (AXEUMM) experiment. Spherical-cap charges fitted with a flat circular metal disk are centrally initiated using an exploding bridgewire detonator while photonic doppler velocimetry is used to probe the metal disk surface velocity and measure its temporal history. The metal disk's jump-off-velocity measurement is combined with conservation equations, material Hugoniots, and select empirical relationships to determine performance properties of the detonation wave (i.e., velocity, pressure, particle velocity, and density). Using the temporal velocity history with the numerical hydrocode CTH, a determination of the energetic material's equation of state and material expansion energy is possible. Initial experimental and computational results for the plastic-bonded energetic formulation PBXN-5 are presented.

  6. Isentropic Compression Experiments on the Z Accelerator

    NASA Astrophysics Data System (ADS)

    Asay, James

    1999-06-01

    Shock compression techniques are the only viable technique for making accurate EOS measurements in the multi-Mbar pressure regime. These experiments provide specific states of pressure, volume and internal energy on the Hugoniot. In many applications, it is necessary to know the off-Hugoniot isentropic loading response of materials to ultra-high pressures. Techniques for measuring isentropic response are challenging. At low pressures, ramp wave generators are used, while at high megabar pressures, graded density impactors are employed. In these latter experiments is a small amplitude shock results in the compression isentrope centered at some initial state. A new technique that is being developed shows promise for performing isentropic experiments with smooth loading to very high pressure. This approach uses the high current densities produced with fast pulsed power accelerators to create continuous magnetic loading to a few hundred kilobars over time intervals of 100-200 ns. The resulting ramp wave propagates through a planar specimen and are measured using time-resolved VISARS. Application of the differential equations of motion over the risetime of the waves determines pressure-volume states continuously. Experiments on copper and iron, have allowed determination of the isentropic compression curve in copper and the evaluation of the kinetic properties of the alpha-epsilon phase transition in iron. In this presentation, I will review previous studies of isentropic compression, discuss the new technique using Z and the results obtained on iron and copper. A perspective on the opportunities for isentropic compression experiments to multi-Mbar pressures, will be given. * Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94AL8500.

  7. 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.

  8. Comparison of integrated numerical experiments with accelerator and FEL experiments

    SciTech Connect

    Thode, L.E.; Carlsten, B.E.; Chan, K.C.D.; Cooper, R.K.; Elliott, J.C.; Gitomer, S.J.; Goldstein, J.C.; Jones, M.E.; McVey, B.D.; Schmitt, M.J.; Takeda, H.; Tokar, R.L.; Wang, T.S.; Young, L.M.

    1991-01-01

    Even at the conceptual level the strong coupling between the laser subsystem elements, such as the accelerator, wiggler, optics, and control, greatly complicates the understanding and design of an FEL. Given the requirements for a high-performance FEL, the coupling between the laser subsystems must be included in the design approach. To address the subsystem coupling the concept of an integrated numerical experiment (INEX) has been implemented. Unique features of the INEX approach are consistency and numerical equivalence of experimental diagnostic. The equivalent numerical diagnostics mitigates the major problem of misinterpretation that often occurs when theoretical and experimental data are compared. A complete INEX model has been applied to the 10{mu}m high-extraction-efficiency experiment at Los Alamos and the 0.6-{mu}m Burst Mode experiment at Boeing Aerospace. In addition, various subsets of the INEX model have been compared with a number of other experiments. Overall, the agreement between INEX and the experiments is very good. With the INEX approach, it now appears possible to design high-performance FELS for numerous applications. The first full-scale test of the INEX approach is the Los Alamos HIBAF experiment. The INEX concept, implementation, and validation with experiments are discussed. 28 refs., 13 figs., 1 tab.

  9. Sandia LSI accelerated aging and data acquisition techniques

    SciTech Connect

    Walker, J.E.

    1980-04-01

    The purpose of the Microelectronic Evaluation Laboratory at Sandia is to develop a program for evaluating CMOS LSI (complementary metal oxide silicon - large scale integrated) technology devices which are being used for the first time in a weapon system. These evaluations are based on accelerated aging studies and electrical tests to determine the reliability and life of the devices. In accelerated aging, specific, controlled stresses are applied to the device to accelerate time-to-failure. Data are used tin mathematical models to estimate life in acutal use. The stresses used for this technology are temperature and voltage. The devices are stored at temperatures with or without voltage applied (steady-state or cyclical) and periodically tested until at least 50% failures are encountered. Since most current technologies use epoxy-die-attachment, aging temperatures must be under 200/sup 0/C. This delays device failure, and a 16% failure level is used when this extrapolation is considered valid. Statistical analysis is performed on the resultant data to predict reliability with time. The equipment and procedures used for accelerated aging tests are described in detail. The data acquisition system and its use are discussed. All devices, after functional failure has occurred, are given to the failure analysis group for failure evaluations. In order to improve reliability predictions, failure analysis is most concerned with the separation of freak and main life mechanisms. Through these evaluations, higher reliability and longer device life have become a milestone of the future. (LCL)

  10. 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.

  11. Energy deposition via magnetoplasmadynamic acceleration: I. Experiment

    NASA Astrophysics Data System (ADS)

    Gilland, James; Mikellides, Pavlos; Marriott, Darin

    2009-02-01

    The expansion of a high-temperature fusion plasma through an expanding magnetic field is a process common to most fusion propulsion concepts. The propulsive efficiency of this process has a strong bearing on the overall performance of fusion propulsion. In order to simulate the expansion of a fusion plasma, a concept has been developed in which a high velocity plasma is first stagnated in a converging magnetic field to high (100s of eV) temperatures, then expanded though a converging/diverging magnetic nozzle. As a first step in constructing this experiment, a gigawatt magnetoplasmadynamic plasma accelerator was constructed to generate the initial high velocity plasma and has been characterized. The source is powered by a 1.6 MJ, 1.6 ms pulse forming network. The device has been operated with currents up to 300 kA and power levels up to 200 MWe. These values are among the highest levels reached in an magnetoplasmadynamic thruster. The device operation has been characterized by quasi-steady voltage and current measurements for helium mass flow rates from 0.5 to 27 g s-1. Probe results for downstream plasma density and electron temperature are also presented. The source behavior is examined in terms of current theories for magnetoplasmadynamic thrusters.

  12. Solder joint aging characteristics from the MC2918 firing set of a B61 accelerated aging unit (AAU)

    SciTech Connect

    Vianco, P.T.; Rejent, J.A.

    1997-10-01

    The B61 accelerated aging unit (AAU) provided a unique opportunity to document the effects of a controlled, long-term thermal cycling environment on the aging of materials used in the device. This experiment was of particular interest to solder technologists because thermal cycling environments are a predominant source of solder joint failures in electronic assemblies. Observations of through hole solder joints in the MC2918 Firing Set from the B61 AAU did not reveal signs of catastrophic failure. Quantitative analyses of the microstructural metrics of intermetallic compound layer thickness and Pb-rich phase particle distributions indicated solder joint aging that was commensurate with the accelerated aging environment. The effects of stress-enhanced coarsening of the Pb-rich phase were also documented.

  13. Argonne plasma wake-field acceleration experiments

    SciTech Connect

    Rosenzweig, J.B.; Cole, B.; Gai, W.; Konecny, R.; Norem, J.; Schoessow, P.; Simpson, J.

    1989-03-14

    Four years after the initial proposal of the Plasma Wake-field Accelerator (PWFA), it continues to be the object of much investigation, due to the promise of the ultra-high accelerating gradients that can exist in relativistic plasma waves driven in the wake of charged particle beams. These wake-fields are of interest both in the laboratory, for acceleration and focusing of electrons and positrons in future linear colliders, and in nature as a possible cosmic ray acceleration mechanism. The purpose of the present work is to review the recent experimental advances made in PWFA research at Argonne National Laboratory. Some of the topics discussed are: the Argonne Advanced Accelerator Test Facility; linear plasma wake-field theory; measurement of linear plasma wake-fields; review of nonlinear plasma wave theory; and experimental measurement of nonlinear plasma wake-fields. 25 refs., 11 figs.

  14. 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.

  15. 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.

  16. Aging accelerates memory extinction and impairs memory restoration in Drosophila.

    PubMed

    Chen, Nannan; Guo, Aike; Li, Yan

    2015-05-15

    Age-related memory impairment (AMI) is a phenomenon observed from invertebrates to human. Memory extinction is proposed to be an active inhibitory modification of memory, however, whether extinction is affected in aging animals remains to be elucidated. Employing a modified paradigm for studying memory extinction in fruit flies, we found that only the stable, but not the labile memory component was suppressed by extinction, thus effectively resulting in higher memory loss in aging flies. Strikingly, young flies were able to fully restore the stable memory component 3 h post extinction, while aging flies failed to do so. In conclusion, our findings reveal that both accelerated extinction and impaired restoration contribute to memory impairment in aging animals. PMID:25842205

  17. 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

  18. 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.

  19. Progranulin Knockout Accelerates Intervertebral Disc Degeneration in Aging Mice

    PubMed Central

    Zhao, Yun-peng; Tian, Qing-yun; Liu, Ben; Cuellar, Jason; Richbourgh, Brendon; Jia, Tang-hong; Liu, Chuan-ju

    2015-01-01

    Intervertebral disc (IVD) degeneration is a common degenerative disease, yet much is unknown about the mechanisms during its pathogenesis. Herein we investigated whether progranulin (PGRN), a chondroprotective growth factor, is associated with IVD degeneration. PGRN was detectable in both human and murine IVD. The levels of PGRN were upregulated in murine IVD tissue during aging process. Loss of PGRN resulted in an early onset of degenerative changes in the IVD tissue and altered expressions of the degeneration-associated molecules in the mouse IVD tissue. Moreover, PGRN knockout mice exhibited accelerated IVD matrix degeneration, abnormal bone formation and exaggerated bone resorption in vertebra with aging. The acceleration of IVD degeneration observed in PGRN null mice was probably due to the enhanced activation of NF-κB signaling and β-catenin signaling. Taken together, PGRN may play a critical role in homeostasis of IVD, and may serve as a potential molecular target for prevention and treatment of disc degenerative diseases. PMID:25777988

  20. Mechanisms of aging in senescence-accelerated mice

    PubMed Central

    Carter, Todd A; Greenhall, Jennifer A; Yoshida, Shigeo; Fuchs, Sebastian; Helton, Robert; Swaroop, Anand; Lockhart, David J; Barlow, Carrolee

    2005-01-01

    Background Progressive neurological dysfunction is a key aspect of human aging. Because of underlying differences in the aging of mice and humans, useful mouse models have been difficult to obtain and study. We have used gene-expression analysis and polymorphism screening to study molecular senescence of the retina and hippocampus in two rare inbred mouse models of accelerated neurological senescence (SAMP8 and SAMP10) that closely mimic human neurological aging, and in a related normal strain (SAMR1) and an unrelated normal strain (C57BL/6J). Results The majority of age-related gene expression changes were strain-specific, with only a few common pathways found for normal and accelerated neurological aging. Polymorphism screening led to the identification of mutations that could have a direct impact on important disease processes, including a mutation in a fibroblast growth factor gene, Fgf1, and a mutation in and ectopic expression of the gene for the chemokine CCL19, which is involved in the inflammatory response. Conclusion We show that combining the study of inbred mouse strains with interesting traits and gene-expression profiling can lead to the discovery of genes important for complex phenotypes. Furthermore, full-genome polymorphism detection, sequencing and gene-expression profiling of inbred mouse strains with interesting phenotypic differences may provide unique insights into the molecular genetics of late-manifesting complex diseases. PMID:15960800

  1. 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.

  2. Accelerated aging of outdoor insulation under acid rain conditions

    NASA Astrophysics Data System (ADS)

    Frost, Nancy Ellen

    2000-11-01

    Outdoor insulation has evolved from glass to ceramics to epoxy in the past decades, and more recently into the area of polymer composites. Accelerated aging must be performed to examine the effectiveness of materials prior to use under actual service conditions. Traditionally this aging has been performed with sodium chloride as the conductive component in the high humidity and wet tests. This approach does not necessarily represent actual service conditions, as globally the precipitation is acidic in nature and contains many constituents in addition to sodium and chloride. The main focus of this work was to examine the effect of acid precipitation on materials used in outdoor insulation applications. This was achieved through the use of a rotating tracking wheel and a controlled high humidity chamber with the application of a synthetic acid rain solution. The analysis techniques utilized to examine the results of the accelerated aging were leakage current monitoring, evaluation of changes in dielectric properties as well as electron microscopy. In addition, changes in hydrophobicity were quantified. Based on experimental observations, a first order life prediction model was developed to investigate the usefulness of the acid rain aging technique. This model was founded on the results of a series of tests conducted with varying solution conductivity, while maintaining constant acid content. This model permits the prediction of the life of a material at normal precipitation conductivity levels.

  3. 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.

  4. 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

  5. In vitro accelerated aging of composites and a sealant.

    PubMed

    Powers, J M; Fan, P L; Marcotte, M

    1981-09-01

    The in vitro accelerated aging of conventional and microfilled composite restorative materials and a sealant was studied. Volume loss/surface area ranged from 2.0 x 10(-3) mm3/mm2 for I to 7.3 x 10(-3) mm3/mm2 for SF after 900 h of aging. Surface morphology of the conventional composites was characterized by crazing and exposure of filler particles. The surfaces of the microfilled composites also showed crazing. The surface morphology of the sealant appeared unchanged. Comparisons of infrared ATR spectra between zero and 900 h of aging showed that slight chemical changes occurred at the surface of AR but not SF. PMID:6943161

  6. 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.

  7. 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.

  8. TeV/m Nano-Accelerator: Current Status of CNT-Channeling Acceleration Experiment

    SciTech Connect

    Shin, Young Min; Lumpkin, Alex H.; Thangaraj, Jayakar Charles; Thurman-Keup, Randy Michael; Shiltsev, Vladimir D.

    2014-09-17

    Crystal channeling technology has offered various opportunities in the accelerator community with a viability of ultrahigh gradient (TV/m) acceleration for future HEP collider. The major challenge of channeling acceleration is that ultimate acceleration gradients might require a high power driver in the hard x-ray regime (~ 40 keV). This x-ray energy exceeds those for x-rays as of today, although x-ray lasers can efficiently excite solid plasma and accelerate particles inside a crystal channel. Moreover, only disposable crystal accelerators are possible at such high externally excited fields which would exceed the ionization thresholds destroying the atomic structure, so acceleration will take place only in a short time before full dissociation of the lattice. Carbon-based nanostructures have great potential with a wide range of flexibility and superior physical strength, which can be applied to channeling acceleration. This paper presents a beam- driven channeling acceleration concept with CNTs and discusses feasible experiments with the Advanced Superconducting Test Accelerator (ASTA) in Fermilab.

  9. 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.

  10. The electron accelerator for the AWAKE experiment at CERN

    NASA Astrophysics Data System (ADS)

    Pepitone, K.; Doebert, S.; Burt, G.; Chevallay, E.; Chritin, N.; Delory, C.; Fedosseev, V.; Hessler, Ch.; McMonagle, G.; Mete, O.; Verzilov, V.; Apsimon, R.

    2016-09-01

    The AWAKE collaboration prepares a proton driven plasma wakefield acceleration experiment using the SPS beam at CERN. A long proton bunch extracted from the SPS interacts with a high power laser and a 10 m long rubidium vapour plasma cell to create strong wakefields allowing sustained electron acceleration. The electron bunch to probe these wakefields is supplied by a 20 MeV electron accelerator. The electron accelerator consists of an RF-gun and a short booster structure. This electron source should provide beams with intensities between 0.1 and 1 nC, bunch lengths between 0.3 and 3 ps and an emittance of the order of 2 mm mrad. The wide range of parameters should cope with the uncertainties and future prospects of the planned experiments. The layout of the electron accelerator, its instrumentation and beam dynamics simulations are presented.

  11. 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

  12. 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

  13. 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

  14. Estimates of effects of residual acceleration on USML-1 experiments

    NASA Technical Reports Server (NTRS)

    Naumann, Robert J.

    1995-01-01

    The purpose of this study effort was to develop analytical models to describe the effects of residual accelerations on the experiments to be carried on the first U.S. Microgravity Lab mission (USML-1) and to test the accuracy of these models by comparing the pre-flight predicted effects with the post-flight measured effects. After surveying the experiments to be performed on USML-1, it became evident that the anticipated residual accelerations during the USML-1 mission were well below the threshold for most of the primary experiments and all of the secondary (Glovebox) experiments and that the only set of experiments that could provide quantifiable effects, and thus provide a definitive test of the analytical models, were the three melt growth experiments using the Bridgman-Stockbarger type Crystal Growth Furnace (CGF). This class of experiments is by far the most sensitive to low level quasi-steady accelerations that are unavoidable on space craft operating in low earth orbit. Because of this, they have been the drivers for the acceleration requirements imposed on the Space Station. Therefore, it is appropriate that the models on which these requirements are based are tested experimentally. Also, since solidification proceeds directionally over a long period of time, the solidified ingot provides a more or less continuous record of the effects from acceleration disturbances.

  15. Laser Wakefield Acceleration Experiments Using HERCULES Laser

    SciTech Connect

    Matsuoka, T.; McGuffey, C.; Dollar, F.; Bulanov, S. S.; Chvykov, V.; Kalintchenko, G.; Rousseau, P.; Yanovsky, V.; Maksimchuk, A.; Krushelnick, K.; Horovitz, Y.

    2009-07-25

    Laser wakefield acceleration (LWFA) in a supersonic gas-jet using a self-guided laser pulse was studied by changing laser power and plasma electron density. The recently upgraded HERCULES laser facility equipped with wavefront correction enables a peak intensity of 6.1x10{sup 19} W/cm{sup 2} at laser power of 80 TW to be delivered to the gas-jet using F/10 focusing optics. We found that electron beam charge was increased significantly with an increase of laser power from 30 TW to 80 TW and showed density threshold behavior at a fixed laser power. We also studied the influence of laser focusing conditions by changing the f-number of the optics to F/15 and found an increase in density threshold for electron production compared to the F/10 configuration. The analysis of different phenomena such as betatron motion of electrons, side scattering of the laser pulse for different focusing conditions, the influence of plasma density down ramp on LWFA are shown.

  16. Chronic inflammation induces telomere dysfunction and accelerates ageing in mice

    PubMed Central

    Jurk, Diana; Wilson, Caroline; Passos, João F.; Oakley, Fiona; Correia-Melo, Clara; Greaves, Laura; Saretzki, Gabriele; Fox, Chris; Lawless, Conor; Anderson, Rhys; Hewitt, Graeme; Pender, Sylvia LF; Fullard, Nicola; Nelson, Glyn; Mann, Jelena; van de Sluis, Bart; Mann, Derek A.; von Zglinicki, Thomas

    2014-01-01

    Chronic inflammation is associated with normal and pathological ageing. Here we show that chronic, progressive low-grade inflammation induced by knockout of the nfkb1 subunit of the transcription factor NF-κB induces premature ageing in mice. We also show that these mice have reduced regeneration in liver and gut. nfkb1−/− fibroblasts exhibit aggravated cell senescence because of an enhanced autocrine and paracrine feedback through NF-κB, COX-2 and ROS, which stabilizes DNA damage. Preferential accumulation of telomere-dysfunctional senescent cells in nfkb1−/− tissues is blocked by anti-inflammatory or antioxidant treatment of mice, and this rescues tissue regenerative potential. Frequencies of senescent cells in liver and intestinal crypts quantitatively predict mean and maximum lifespan in both short- and long-lived mice cohorts. These data indicate that systemic chronic inflammation can accelerate ageing via ROS-mediated exacerbation of telomere dysfunction and cell senescence in the absence of any other genetic or environmental factor. PMID:24960204

  17. 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.

  18. 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.

  19. Facilitating an accelerated experience-based co-design project.

    PubMed

    Tollyfield, Ruth

    This article describes an accelerated experience-based co-design (AEBCD) quality improvement project that was undertaken in an adult critical care setting and the facilitation of that process. In doing so the aim is to encourage other clinical settings to engage with their patients, carers and staff alike and undertake their own quality improvement project. Patient, carer and staff experience and its place in the quality sphere is outlined and the importance of capturing patient, carer and staff feedback established. Experience-based co-design (EBCD) is described along with the recently tested accelerated version of the process. An overview of the project and outline of the organisational tasks and activities undertaken by the facilitator are given. The facilitation of the process and key outcomes are discussed and reflected on. Recommendations for future undertakings of the accelerated process are given and conclusions drawn. PMID:24526020

  20. Ultrashort laser pulse driven inverse free electron laser accelerator experiment

    NASA Astrophysics Data System (ADS)

    Moody, J. T.; Anderson, S. G.; Anderson, G.; Betts, S.; Fisher, S.; Tremaine, A.; Musumeci, P.

    2016-02-01

    In this paper we discuss the ultrashort pulse high gradient inverse free electron laser accelerator experiment carried out at the Lawrence Livermore National Laboratory which demonstrated gradients exceeding 200 MV /m using a 4 TW 100 fs long 800 nm Ti :Sa laser pulse. Due to the short laser and electron pulse lengths, synchronization was determined to be one of the main challenges in this experiment. This made necessary the implementation of a single-shot, nondestructive, electro-optic sampling based diagnostics to enable time-stamping of each laser accelerator shot with <100 fs accuracy. The results of this experiment are expected to pave the way towards the development of future GeV-class IFEL accelerators.

  1. Choosing experiments to accelerate collective discovery

    PubMed Central

    Rzhetsky, Andrey; Foster, Jacob G.; Foster, Ian T.

    2015-01-01

    A scientist’s choice of research problem affects his or her personal career trajectory. Scientists’ combined choices affect the direction and efficiency of scientific discovery as a whole. In this paper, we infer preferences that shape problem selection from patterns of published findings and then quantify their efficiency. We represent research problems as links between scientific entities in a knowledge network. We then build a generative model of discovery informed by qualitative research on scientific problem selection. We map salient features from this literature to key network properties: an entity’s importance corresponds to its degree centrality, and a problem’s difficulty corresponds to the network distance it spans. Drawing on millions of papers and patents published over 30 years, we use this model to infer the typical research strategy used to explore chemical relationships in biomedicine. This strategy generates conservative research choices focused on building up knowledge around important molecules. These choices become more conservative over time. The observed strategy is efficient for initial exploration of the network and supports scientific careers that require steady output, but is inefficient for science as a whole. Through supercomputer experiments on a sample of the network, we study thousands of alternatives and identify strategies much more efficient at exploring mature knowledge networks. We find that increased risk-taking and the publication of experimental failures would substantially improve the speed of discovery. We consider institutional shifts in grant making, evaluation, and publication that would help realize these efficiencies. PMID:26554009

  2. Surface degradation of polymer insulators under accelerated climatic aging in weather-ometer

    SciTech Connect

    Xu, G.; McGrath, P.B.; Burns, C.W.

    1996-12-31

    Climatic aging experiments were conducted on two types of outdoor polymer insulators by using a programmable weather-ometer. The housing materials for the insulators were silicone rubber (SR) and ethylene propylene diene monomer (EPDM). The accelerated aging stresses were comprised of ultraviolet radiation, elevated temperature, temperature cycling, thermal shock and high humidity. Their effects on the insulator surface conditions and electrical performance wee examined through visual inspection and SEM studies, contact angle measurements, thermogravimetric analysis (TGA), energy dispersive spectroscopy (EDS) analysis, and 50% impulse flashover voltage tests. The results showed a significant damage on the insulator surface caused by some of the imposed aging stresses. The EDS analysis suggested a photooxidation process that happened on the insulator surface during the aging period.

  3. 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.

  4. Space experiments with particle accelerators (SEPAC): Description of instrumentation

    NASA Technical Reports Server (NTRS)

    Taylor, W. W. L.; Roberts, W. T.; Reasoner, D. L.; Chappell, C. R.; Baker, B. B.; Burch, J. L.; Gibson, W. C.; Black, R. K.; Tomlinson, W. M.; Bounds, J. R.

    1987-01-01

    SEPAC (Space Experiments with Particle Accelerators) flew on Spacelab 1 (SL 1) in November and December 1983. SEPAC is a joint U.S.-Japan investigation of the interaction of electron, plasma, and neutral beams with the ionosphere, atmosphere and magnetosphere. It is scheduled to fly again on Atlas 1 in August 1990. On SL 1, SEPAC used an electron accelerator, a plasma accelerator, and neutral gas source as active elements and an array of diagnostics to investigate the interactions. For Atlas 1, the plasma accelerator will be replaced by a plasma contactor and charge collection devices to improve vehicle charging meutralization. This paper describes the SEPAC instrumentation in detail for the SL 1 and Atlas 1 flights and includes a bibliography of SEPAC papers.

  5. 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.

  6. Micro-Bubble Experiments at the Van de Graaff Accelerator

    SciTech Connect

    Sun, Z. J.; Wardle, Kent E.; Quigley, K. J.; Gromov, Roman; Youker, A. J.; Makarashvili, Vakhtang; Bailey, James; Stepinski, D. C.; Chemerisov, S. D.; Vandegrift, G. F.

    2015-02-01

    In order to test and verify the experimental designs at the linear accelerator (LINAC), several micro-scale bubble ("micro-bubble") experiments were conducted with the 3-MeV Van de Graaff (VDG) electron accelerator. The experimental setups included a square quartz tube, sodium bisulfate solution with different concentrations, cooling coils, gas chromatography (GC) system, raster magnets, and two high-resolution cameras that were controlled by a LabVIEW program. Different beam currents were applied in the VDG irradiation. Bubble generation (radiolysis), thermal expansion, thermal convection, and radiation damage were observed in the experiments. Photographs, videos, and gas formation (O2 + H2) data were collected. The micro-bubble experiments at VDG indicate that the design of the full-scale bubble experiments at the LINAC is reasonable.

  7. Nuclear effects in atmospheric and accelerator neutrino experiments

    SciTech Connect

    Chauhan, S.; Athar, M. Sajjad; Singh, S. K.

    2010-11-24

    We have studied the nuclear medium effects in the neutrino (antineutrino) induced interactions in nuclei at intermediate energy region. We have applied this study to calculate the event rates for atmospheric and accelerator neutrino experiments. The study of the nuclear effects has been done for the quasielastic lepton production and the charged current incoherent and coherent pion production processes.

  8. The Student Course Experience among Online, Accelerated, and Traditional Courses

    ERIC Educational Resources Information Center

    Bielitz, Colleen L.

    2016-01-01

    The demand by the public for a wider variety of course formats has led to complexity in determining a course's optimal delivery format as many faculty members still believe that online and accelerated courses do not offer students an equivalent experience to traditional face to face instruction. The purpose of this quantitative, comparative study…

  9. Constant Acceleration: Experiments with a Fan-Driven Dynamics Cart.

    ERIC Educational Resources Information Center

    Morse, Robert A.

    1993-01-01

    Describes the rebuilding of a Project Physics fan cart on a PASCO dynamics cart chassis for achieving greatly reduced frictional forces. Suggests four experiments for the rebuilt cart: (1) acceleration on a level track, (2) initial negative velocity, (3) different masses and different forces, and (4) inclines. (MVL)

  10. Accelerator-based Experiments For Introductory-level Undergraduates

    SciTech Connect

    Sanders, Justin M.

    2009-03-10

    Although accelerator based experiments for undergraduates are often considered only for junior or senior physics majors, introductory students can also benefit from them. Rutherford backscattering and a {sup 12}C(p,p){sup 12}C elastic scattering resonance can be presented in ways that are well-suited for students who have taken only an introductory physics course.

  11. Magnetohydrodynamic Particle Acceleration Processes: SSX Experiments, Theory, and Astrophysical Applications

    SciTech Connect

    Brown, Michael R.

    2006-11-16

    Project Title: Magnetohydrodynamic Particle Acceleration Processes: SSX Experiments, Theory, and Astrophysical Applications PI: Michael R. Brown, Swarthmore College The purpose of the project was to provide theoretical and modeling support to the Swarthmore Spheromak Experiment (SSX). Accordingly, the theoretical effort was tightly integrated into the SSX experimental effort. During the grant period, Michael Brown and his experimental collaborators at Swarthmore, with assistance from W. Matthaeus as appropriate, made substantial progress in understanding the physics SSX plasmas.

  12. Results of the SINGAP Neutral Beam Accelerator Experiment at JAEA

    NASA Astrophysics Data System (ADS)

    de Esch, H. P. L.; Svensson, L.; Inoue, T.; Taniguchi, M.; Umeda, N.; Kashiwagi, M.; Fubiani, G.

    2009-03-01

    IRFM (CEA Cadarache) and JAEA Naka have entered into a collaboration in order to test a SINGAP [1] accelerator at the JAEA Megavolt Test Facility (MTF) at Naka, Japan. Whereas at the CEA testbed the acceleration current was limited to 0.1 A, at JAEA 0.5 A is available. This allows the acceleration of 15 H- beamlets in SINGAP to be tested and a direct comparison between SINGAP and MAMuG [2] to be made. High-voltage conditioning in the SINGAP configuration has been quite slow, with 581 kV in vacuum achieved after 140 hours of conditioning. With 0.1 Pa of H2 gas present in the accelerator 787 kV could be achieved. The conditioning curve for MAMuG is 200 kV higher. SINGAP beam optics appears in agreement with calculation results. A beamlet divergence better than 5 mrad was obtained. SINGAP accelerates electrons to a higher energy than MAMuG. Measurements of the power intercepted on one of the electron dumps have been compared with EAMCC code [3] calculations. Based on the experiments described here, electron production by a SINGAP accelerator scaled up to ITER size was estimated to be too high for comfort

  13. First results of the plasma wakefield acceleration experiment at PITZ

    NASA Astrophysics Data System (ADS)

    Lishilin, O.; Gross, M.; Brinkmann, R.; Engel, J.; Grüner, F.; Koss, G.; Krasilnikov, M.; Martinez de la Ossa, A.; Mehrling, T.; Osterhoff, J.; Pathak, G.; Philipp, S.; Renier, Y.; Richter, D.; Schroeder, C.; Schütze, R.; Stephan, F.

    2016-09-01

    The self-modulation instability of long particle beams was proposed as a new mechanism to produce driver beams for proton driven plasma wakefield acceleration (PWFA). The PWFA experiment at the Photo Injector Test facility at DESY, Zeuthen site (PITZ) was launched to experimentally demonstrate and study the self-modulation of long electron beams in plasma. Key aspects for the experiment are the very flexible photocathode laser system, a plasma cell and well-developed beam diagnostics. In this contribution we report about the plasma cell design, preparatory experiments and the results of the first PWFA experiment at PITZ.

  14. Statistical analysis of accelerated temperature aging of semiconductor devices

    NASA Astrophysics Data System (ADS)

    Johnson, W. A.; Milles, M. F.

    1981-05-01

    A number of semiconductor devices taken from a distribution were operated at several elevated temperatures to induce failure in all devices within a reasonable time. Assuming general characteristics of the device failure probability density function (pdf) and its temperature dependence, the expected cumulative failure function (cff) for devices in normal operation were estimated based on statistical inference, taking the average probability of a random device (from the same distribution but operated at a normal temperature) failing as a function of time. A review of the mathematical formalism employed in semiconductor reliability discussions is included. Three failure pdf's at particular usefulness to this analysis--exponential, normal, and lognormal - are discussed. The cff, at times orders of magnitude loss then, at times comparable to the desired system useful, life (*10 to the 4th power to 10 to the 5th power hr) is considered. A review of accelerated temperature aging is presented, and the assumption concerning the general characteristics of the failure pdf, which are fundamental to this analysis, are emphasized.

  15. Experiment to Detect Accelerating Modes in a Photonic Bandgap Fiber

    SciTech Connect

    England, R. J.; Colby, E. R.; McGuinness, C. M.; Noble, R.; Plettner, T.; Siemann, R. H.; Spencer, J. E.; Walz, D.; Ischebeck, R.; Sears, C. M. S.

    2009-01-22

    An experimental effort is currently underway at the E-163 test beamline at Stanford Linear Accelerator Center to use a hollow-core photonic bandgap (PBG) fiber as a high-gradient laser-based accelerating structure for electron bunches. For the initial stage of this experiment, a 50 pC, 60 MeV electron beam will be coupled into the fiber core and the excited modes will be detected using a spectrograph to resolve their frequency signatures in the wakefield radiation generated by the beam. We will describe the experimental plan and recent simulation studies of candidate fibers.

  16. The laser driven particle accelerator project: Theory and experiment

    SciTech Connect

    Plettner, T.; Byer, R.L. Smith, T.I.; Siemann, R.H. Huang, Y.C.

    1999-07-01

    A proof of principle experiment for laser driven electron acceleration from crossed laser beams in a dielectric loaded vacuum is being carried out at Stanford University. We seek to measure a maximum energy gain of about 250 keV for a 30{endash}35 MeV electron beam in one accelerator cell. We use laser pulses of a few picoseconds of duration from a regenerative Ti:sapphire laser amplifier at a wavelength of 800 nm in a laser-electron interaction distance of {approximately}1 mm. {copyright} {ital 1999 American Institute of Physics.}

  17. Experiment to Detect Accelerating Modes in a Photonic Bandgap Fiber

    SciTech Connect

    England, R.J.; Colby, E.R.; Ischebeck, R.; McGuinness, C.M.; Noble, R.; Plettner, T.; Sears, C.M.S.; Siemann, R.H.; Spencer, J.E.; Walz, D.; /SLAC

    2011-11-21

    An experimental effort is currently underway at the E-163 test beamline at Stanford Linear Accelerator Center to use a hollow-core photonic bandgap (PBG) fiber as a high-gradient laser-based accelerating structure for electron bunches. For the initial stage of this experiment, a 50pC, 60 MeV electron beam will be coupled into the fiber core and the excited modes will be detected using a spectrograph to resolve their frequency signatures in the wakefield radiation generated by the beam. They will describe the experimental plan and recent simulation studies of candidate fibers.

  18. Results from T2K and accelerator oscillation experiments

    NASA Astrophysics Data System (ADS)

    Bronner, C.

    2012-08-01

    Various experiments use secondary neutrino beams produced by accelerators to study neutrino oscillations. In this article, we will review oscillation results from a number of those experiments (MINOS, OPERA), and focus more on results from T2K. This long baseline off-axis experiment uses a beam of muon neutrinos produced in J-PARC in Japan to study muon neutrino disappearance in order to measure atmospheric parameters, as well as studying electron neutrino appearance to measure the 13 mixing angle. We will present in particular very recent results of those measurements obtained by MINOS and T2K.

  19. 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

  20. Absolute acceleration measurements on STS-50 from the Orbital Acceleration Research Experiment (OARE)

    NASA Technical Reports Server (NTRS)

    Blanchard, Robert C.; Nicholson, John Y.; Ritter, James R.

    1994-01-01

    Orbital Acceleration Research Experiment (OARE) data on Space Transportation System (STS)-50 have been examined in detail during a 2-day time period. Absolute acceleration levels have been derived at the OARE location, the orbiter center-of-gravity, and at the STS-50 spacelab Crystal Growth Facility. During the interval, the tri-axial OARE raw telemetered acceleration measurements have been filtered using a sliding trimmed mean filter in order to remove large acceleration spikes (e.g., thrusters) and reduce the noise. Twelve OARE measured biases in each acceleration channel during the 2-day interval have been analyzed and applied to the filtered data. Similarly, the in situ measured x-axis scale factors in the sensor's most sensitive range were also analyzed and applied to the data. Due to equipment problem(s) on this flight, both y- and z-axis sensitive range scale factors were determined in a separate process using orbiter maneuvers and subsequently applied to the data. All known significant low-frequency corrections at the OARE location (i.e., both vertical and horizontal gravity-gradient, and rotational effects) were removed from the filtered data in order to produce the acceleration components at the orbiter center-of-gravity, which are the aerodynamic signals along each body axis. Results indicate that there is a force being applied to the Orbiter in addition to the aerodynamic forces. The OARE instrument and all known gravitational and electromagnetic forces have been reexamined, but none produces the observed effect. Thus, it is tentatively concluded that the orbiter is creating the environment observed. At least part of this force is thought to be due to the Flash Evaporator System.

  1. The Awful Truth About Zero-Gravity: Space Acceleration Measurement System; Orbital Acceleration Research Experiment

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Earth's gravity holds the Shuttle in orbit, as it does satellites and the Moon. The apparent weightlessness experienced by astronauts and experiments on the Shuttle is a balancing act, the result of free-fall, or continuously falling around Earth. An easy way to visualize what is happening is with a thought experiment that Sir Isaac Newton did in 1686. Newton envisioned a mountain extending above Earth's atmosphere so that friction with the air would be eliminated. He imagined a cannon atop the mountain and aimed parallel to the ground. Firing the cannon propels the cannonball forward. At the same time, Earth's gravity pulls the cannonball down to the surface and eventual impact. Newton visualized using enough powder to just balance gravity so the cannonball would circle the Earth. Like the cannonball, objects orbiting Earth are in continuous free-fall, and it appears that gravity has been eliminated. Yet, that appearance is deceiving. Activities aboard the Shuttle generate a range of accelerations that have effects similar to those of gravity. The crew works and exercises. The main data relay antenna quivers 17 times per second to prevent 'stiction,' where parts stick then release with a jerk. Cooling pumps, air fans, and other systems add vibration. And traces of Earth's atmosphere, even 200 miles up, drag on the Shuttle. While imperceptible to us, these vibrations can have a profound impact on the commercial research and scientific experiments aboard the Shuttle. Measuring these forces is necessary so that researchers and scientists can see what may have affected their experiments when analyzing data. On STS-107 this service is provided by the Space Acceleration Measurement System for Free Flyers (SAMS-FF) and the Orbital Acceleration Research Experiment (OARE). Precision data from these two instruments will help scientists analyze data from their experiments and eliminate outside influences from the phenomena they are studying during the mission.

  2. Ultra-High Gradient Dielectric Wakefield Accelerator Experiments

    SciTech Connect

    Thompson, M. C.; Badakov, H.; Rosenzweig, J. B.; Travis, G.; Hogan, M.; Ischebeck, R.; Kirby, N.; Siemann, R.; Walz, D.; Muggli, P.; Scott, A.; Yoder, R.

    2006-11-27

    Ultra-high gradient dielectric wakefield accelerators are a potential option for a linear collider afterburner since they are immune to the ion collapse and electron/positron asymmetry problems implicit in a plasma based afterburner. The first phase of an experiment to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range has been completed. The experiment took advantage of the unique SLAC FFTB electron beam and its ultra-short pulse lengths and high currents (e.g., {sigma}z = 20 {mu}m at Q = 3 nC). The FFTB electron beam was successfully focused down and sent through short lengths of fused silica capillary tubing (ID = 200 {mu}m / OD = 325 {mu}m). The pulse length of the electron beam was varied to produce a range of electric fields between 2 and 20 GV/m at the inner surface of the dielectric tubes. We observed a sharp increase in optical emissions from the capillaries in the middle part of this surface field range which we believe indicates the transition between sustainable field levels and breakdown. If this initial interpretation is correct, the surfaced fields that were sustained equate to on axis accelerating field of several GV/m. In future experiments being developed for the SLAC SABER and BNL ATF we plan to use the coherent Cerenkov radiation emitted from the capillary tube as a field strength diagnostic and demonstrate GV/m range particle energy gain.

  3. Ultra-High Gradient Dielectric Wakefield Accelerator Experiments

    NASA Astrophysics Data System (ADS)

    Thompson, M. C.; Badakov, H.; Rosenzweig, J. B.; Travis, G.; Hogan, M.; Ischebeck, R.; Kirby, N.; Siemann, R.; Walz, D.; Muggli, P.; Scott, A.; Yoder, R.

    2006-11-01

    Ultra-high gradient dielectric wakefield accelerators are a potential option for a linear collider afterburner since they are immune to the ion collapse and electron/positron asymmetry problems implicit in a plasma based afterburner. The first phase of an experiment to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range has been completed. The experiment took advantage of the unique SLAC FFTB electron beam and its ultra-short pulse lengths and high currents (e.g., σz = 20 μm at Q = 3 nC). The FFTB electron beam was successfully focused down and sent through short lengths of fused silica capillary tubing (ID = 200 μm / OD = 325 μm). The pulse length of the electron beam was varied to produce a range of electric fields between 2 and 20 GV/m at the inner surface of the dielectric tubes. We observed a sharp increase in optical emissions from the capillaries in the middle part of this surface field range which we believe indicates the transition between sustainable field levels and breakdown. If this initial interpretation is correct, the surfaced fields that were sustained equate to on axis accelerating field of several GV/m. In future experiments being developed for the SLAC SABER and BNL ATF we plan to use the coherent Cerenkov radiation emitted from the capillary tube as a field strength diagnostic and demonstrate GV/m range particle energy gain.

  4. Ultra-High Gradient Dielectric Wakefield Accelerator Experiments

    SciTech Connect

    Thompson, M.C.; Badakov, H.; Rosenzweig, J.B.; Travish, G.; Hogan, M.; Ischebeck, R.; Kirby, N.; Siemann, R.; Walz, D.; Muggli, P.; Scott, A.; Yoder, R.; /LLNL, Livermore /UCLA /SLAC /Southern California U. /UC, Santa Barbara /Manhattan Coll., Riverdale

    2007-03-27

    Ultra-high gradient dielectric wakefield accelerators are a potential option for a linear collider afterburner since they are immune to the ion collapse and electron/positron asymmetry problems implicit in a plasma based afterburner. The first phase of an experiment to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range has been completed. The experiment took advantage of the unique SLAC FFTB electron beam and its ultra-short pulse lengths and high currents (e.g., {sigma}{sub z} = 20 {micro}m at Q = 3 nC). The FFTB electron beam was successfully focused down and sent through short lengths of fused silica capillary tubing (ID = 200 {micro}m/OD = 325 {micro}m). The pulse length of the electron beam was varied to produce a range of electric fields between 2 and 20 GV/m at the inner surface of the dielectric tubes. We observed a sharp increase in optical emissions from the capillaries in the middle part of this surface field range which we believe indicates the transition between sustainable field levels and breakdown. If this initial interpretation is correct, the surfaced fields that were sustained equate to on axis accelerating field of several GV/m. In future experiments being developed for the SLAC SABER and BNL ATF we plan to use the coherent Cerenkov radiation emitted from the capillary tube as a field strength diagnostic and demonstrate GV/m range particle energy gain.

  5. Ultra-High Gradient Dielectric Wakefield Accelerator Experiments

    SciTech Connect

    Thompson, M C; Badakov, H; Rosenzweig, J B; Travish, G; Hogan, M; Ischebeck, R; Kirby, N; Siemann, R; Walz, D; Muggli, P; Scott, A; Yoder, R

    2006-08-04

    Ultra-high gradient dielectric wakefield accelerators are a potential option for a linear collider afterburner since they are immune to the ion collapse and electron/positron asymmetry problems implicit in a plasma based afterburner. The first phase of an experiment to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range has been completed. The experiment took advantage of the unique SLAC FFTB electron beam and its ultra-short pulse lengths and high currents (e.g., {sigma}{sub z} = 20 {micro}m at Q = 3 nC). The FFTB electron beam was successfully focused down and sent through short lengths of fused silica capillary tubing (ID = 200 {micro}m/OD = 325 {micro}m). The pulse length of the electron beam was varied to produce a range of electric fields between 2 and 20 GV/m at the inner surface of the dielectric tubes. We observed a sharp increase in optical emissions from the capillaries in the middle part of this surface field range which we believe indicates the transition between sustainable field levels and breakdown. If this initial interpretation is correct, the surfaced fields that were sustained equate to on axis accelerating field of several GV/m. In future experiments being developed for the SLAC SABER and BNL ATF we plan to use the coherent Cerenkov radiation emitted from the capillary tube as a field strength diagnostic and demonstrate GV/m range particle energy gain.

  6. TRIDAQ systems in HEP experiments at LHC accelerator

    NASA Astrophysics Data System (ADS)

    Zagozdzińska, Agnieszka; Romaniuk, Ryszard S.; Poźniak, Krzysztof T.; Zalewski, Piotr

    2013-01-01

    The paper describes Trigger and Data Acquisition (TRIDAQ) systems of accelerator experiments for High Energy Physics. The background for physics research comprises assumptions of the Standard Model theory with basic extensions. On this basis, a structure of particle detector system is described, with emphasis on the following functional blocks: Front-End Electronics, Trigger and DAQ systems. The described solutions are used in the LHC experiments: ATLAS, ALICE, CMS and LHCb. They are also used in other accelerator experiments. Data storage and processing functionality is divided into two hardware systems: Trigger and Data Acquisition, that are dependent on each other. High input data rate impose relevant choices for the architecture and parameters of both systems. The key parameters include detailed system structure and its overall latency. Trigger structure is defined by the physics requirements and the storage capability of DAQ system. Both systems are designed to achieve the highest possible space and time resolution for particle detection. Trigger references are reviewed [1-43] as well as chosen accelerator research efforts origination in this country [44-83].

  7. Cryogenic supply for accelerators and experiments at FAIR

    SciTech Connect

    Kauschke, M.; Xiang, Y.; Schroeder, C. H.; Streicher, B.; Kollmus, H.

    2014-01-29

    In the coming years the new international accelerator facility FAIR (Facility for Antiproton and Ion Research), one of the largest research projects worldwide, will be built at GSI. In the final construction FAIR consists of synchrotrons and storage rings with up to 1,100 meters in circumference, two linear accelerators and about 3.5 kilometers beam transfer lines. The existing GSI accelerators serve as pre-accelerators. Partly the new machines will consist of superconducting magnets and therefore require a reliable supply with liquid helium. As the requirements for the magnets is depending on the machine and have a high variety, the cooling system is different for each machine; two phase cooling, forced flow cooling and bath cooling respectively. In addition the cold mass of the individual magnets varies between less than 1t up to 80t and some magnets will cause a dynamic heat load due to ramping that is higher than the static loads. The full cryogenic system will be operated above atmospheric pressure. The refrigeration and liquefaction power will be provided by two main cryogenic plants of 8 and 25 kW at 4K and two smaller plants next to the experiments.

  8. Dielectric Wakefield Accelerator Experiments at the SABER Facility

    SciTech Connect

    Kanareykin, A.; Thompson, M.C.; Berry, M.K.; Blumenfeld, I.; Decker, F.J.; Hogan, M.J.; Ischebeck, R.; Iverson, R.H.; Kirby, N.A.; Siemann, Robert H.; Walz, D.R.; Badakov, H.; Cook, A.M.; Rosenzweig, J.B.; Tikhoplav, R.; Travish, G.; Muggli, P.; /Southern California U.

    2008-01-28

    Electron bunches with the unparalleled combination of high charge, low emittances, and short time duration, as first produced at the SLAC Final Focus Test Beam (FFTB), are foreseen to be produced at the SABER facility. These types of bunches have enabled wakefield driven accelerating schemes of multi-GV/m in plasmas. In the context of the Dielectric Wakefield Accelerators (DWA) such beams, having rms bunch length as short as 20 um, have been used to drive 100 um and 200 um ID hollow tubes above 20 GV/m surface fields. These FFTB tests enabled the measurement of a breakdown threshold in fused silica (with full data analysis still ongoing) [1]. With the construction and commissioning of the SABER facility at SLAC, new experiments would be made possible to test further aspects of DWAs including materials, tube geometrical variations, direct measurements of the Cerenkov fields, and proof of acceleration in tubes >10 cm in length. This collaboration will investigate breakdown thresholds and accelerating fields in new materials including CVD diamond. Here we describe the experimental plans, beam parameters, simulations, and progress to date as well as future prospects for machines based of DWA structures.

  9. Inverse Cerenkov laser accelerator experiment annual report. 1990 Annual report

    SciTech Connect

    Not Available

    1991-03-29

    During the past year further progress was made on preparations for the Spectra Technology, Inc. (STI) inverse Cerenkov acceleration (ICA) experiment to be performed on the Accelerator Test Facility (ATF) at Brookhaven National Laboratory. Major progress was made in the design and fabrication of the experimental apparatus. This includes the gas cell, where the ICA process occurs, and the optical system that converts the CO{sub 2} laser beam into a radially polarized beam. In terms of progress on theoretical work, the authors finished optimizing the ATF ICA design parameters using their Monte Carlo computer simulation. The optimized design predicts for the ATF conditions that over 50% energy gain should be observed. They published a paper on an improved method of performing ICA by operating near the resonance of a gas. They also began analysis of a method of accelerating particles in a vacuum using a radially polarized beam and axicon focusing. Although this new method can no longer be considered ICA, it has the potential of high acceleration gradients without the drawbacks of gas scattering and gas breakdown. Three papers were published and two conference papers were presented during 1990.

  10. Structure Loaded Vacuum Laser-Driven Particle Acceleration Experiments at SLAC

    SciTech Connect

    Plettner, T.; Byer, R.L.; Colby, E.R.; Cowan, B.M.; Ischebeck, R.; McGuinness, C.; Lincoln, M.R.; Sears, C.M.; Siemann, R.H.; Spencer, J.E.; /SLAC /Stanford U., Phys. Dept.

    2007-04-09

    We present an overview of the future laser-driven particle acceleration experiments. These will be carried out at the E163 facility at SLAC. Our objectives include a reconfirmation of the proof-of-principle experiment, a staged buncher laser-accelerator experiment, and longer-term future experiments that employ dielectric laser-accelerator microstructures.

  11. 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

  12. An inverse free electron laser accelerator: Experiment and theoretical interpretation

    SciTech Connect

    Fang, Jyan-Min

    1997-06-01

    Experimental and numerical studies of the Inverse Free Electron Laser using a GW-level 10.6 {mu}m CO{sub 2} laser have been carried out at Brookhaven`s Accelerator Test Facility. An energy gain of 2.5 % ({Delta}E/E) on a 40 MeV electron beam has been observed E which compares well with theory. The effects on IFEL acceleration with respect to the variation of the laser electric field, the input electron beam energy, and the wiggler magnetic field strength were studied, and show the importance of matching the resonance condition in the IFEL. The numerical simulations were performed under various conditions and the importance of the electron bunching in the IFEL is shown. The numerical interpretation of our IFEL experimental results was examined. Although good numerical agreement with the experimental results was obtained, there is a discrepancy between the level of the laser power measured in the experiment and used in the simulation, possibly due to the non-Gaussian profile of the input high power laser beam. The electron energy distribution was studied numerically and a smoothing of the energy spectrum by the space charge effect at the location of the spectrometer was found, compared with the spectrum at the exit of the wiggler. The electron bunching by the IFEL and the possibility of using the IFEL as an electron prebuncher for another laser-driven accelerator were studied numerically. We found that bunching of the electrons at 1 meter downstream from the wiggler can be achieved using the existing facility. The simulation shows that there is a fundamental difference between the operating conditions for using the IFEL as a high gradient accelerator, and as a prebuncher for another accelerator.

  13. 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

  14. Comparison of mice with accelerated aging caused by distinct mechanisms.

    PubMed

    Gurkar, Aditi U; Niedernhofer, Laura J

    2015-08-01

    Aging is the primary risk factor for numerous chronic, debilitating diseases. These diseases impact quality of life of the elderly and consume a large portion of health care costs. The cost of age-related diseases will only increase as the world's population continues to live longer. Thus it would be advantageous to consider aging itself as a therapeutic target, potentially stemming multiple age-related diseases simultaneously. While logical, this is extremely challenging as the molecular mechanisms that drive aging are still unknown. Furthermore, clinical trials to treat aging are impractical. Even in preclinical models, testing interventions to extend healthspan in old age are lengthy and therefore costly. One approach to expedite aging studies is to take advantage of mouse strains that are engineered to age rapidly. These strains are genetically and phenotypically quite diverse. This review aims to offer a comparison of several of these strains to highlight their relative strengths and weaknesses as models of mammalian and more specifically human aging. Additionally, careful identification of commonalities among the strains may lead to the identification of fundamental pathways of aging. PMID:25617508

  15. Hypervelocity macroparticle accelerator experiments at CEM-UT

    NASA Astrophysics Data System (ADS)

    Weeks, D. A.; Weldon, W. F.; Zowarka, R. C., Jr.

    1991-01-01

    Railgun experiments designed to accelerate projectile masses of 2 to 5 g to velocities greater than 6 km/s were performed. Two parallel rail-type accelerators with 12.7-mm square bores were used for the experiments. One gun is 2 m long and has Mo rails and Al2O3 insulators. The other is 1 m long and has Mo rails and granite insulators. The greatest velocity achieved was 5.1 km/s. The following ideas to enhance performance were tested: stiff-gun structures to reduce plasma leakage and rail movement, refractory bore materials to reduce ablation and frictional losses, and prefilling the gun bore with gases to eliminate precursor arcs. After three experiments with the 2-m-long launcher at peak currents 660-780 kA, a gun barrel with 96 percent Al2O3 insulators and 99.9 percent Mo rails (hydraulically contained and preloaded) has survived with minimal damage and no degradation of seals. This launcher configuration is capable of maintaining 0.4 torr rough vacuum for over 1 h after disconnecting the roughing pump used to evacuate the gun.

  16. Analysis of Capillary Guided Laser Plasma Accelerator Experiments at LBNL

    SciTech Connect

    Nakamura, K.; Esarey, E.; Leemans, W. P.; Gonsalves, A. J.; Panasenko, D.; Toth, Cs.; Geddes, C. G. R.; Schroeder, C. B.; Lin, C.

    2009-01-22

    Laser wakefield acceleration experiments were carried out by using a hydrogen-filled capillary discharge waveguide. For a 15 mm long, 200 {mu}m diameter capillary, quasi-monoenergetic e-beams up to 300 MeV were observed. By de-tuning discharge delay from optimum guiding performance, self-trapping was found to be stabilized. For a 33 mm long, 300 {mu}m capillary, a parameter regime with high energy electron beams, up to 1 GeV, was found. In this regime, the electron beam peak energy was correlated with the amount of trapped electrons.

  17. Analysis of Capillary Guided Laser Plasma Accelerator Experiments at LBNL

    SciTech Connect

    Advanced Light Source; Nakamura, Kei; Gonsalves, Anthony; Panasenko, Dmitriy; Lin, Chen; Toth, Csaba; Geddes, Cameron; Schroeder, Carl; Esarey, Eric; Leemans, Wim

    2008-09-29

    Laser wakefield acceleration experiments were carried out by using a hydrogen-filledcapillary discharge waveguide. For a 15 mm long, 200 mu m diameter capillary, quasi-monoenergetic e-beams up to 300 MeV were observed. By de-tuning discharge delay from optimum guiding performance, self-trapping was found to be stabilized. For a 33 mm long, 300 mu m capillary, a parameter regime with high energy electron beams, up to 1 GeV, was found. In this regime, the electron beam peak energy was correlated with the amount of trapped electrons.

  18. Subjective Acceleration of Time Experience in Everyday Life across Adulthood

    ERIC Educational Resources Information Center

    John, Dennis; Lang, Frieder R.

    2015-01-01

    Most people believe that time seems to pass more quickly as they age. Building on assumptions of socioemotional selectivity theory, we investigated whether awareness that one's future lifetime is limited is associated with one's experience of time during everyday activities across adulthood in 3 studies. In the first 2 studies (Study 1: N = 608;…

  19. High Temperature μSR Experiments for Accelerator Developments

    NASA Astrophysics Data System (ADS)

    Ohmori, Chihiro; Koda, Akihiro; Miyake, Yasuhiro; Nishiyama, Kusuo; Shimomura, Koichiro; Schnase, Alexander; Ezura, Eiji; Hara, Keigo; Hasegawa, Katsushi; Nomura, Masahiro; Shimada, Taihei; Takata, Koji; Tamura, Fumihiko; Toda, Makoto; Yamamoto, Masanobu; Yoshii, Masahito

    High temperature μSR is a powerful technique to study magnetic materials. In J-PARC accelerator synchrotrons, the Rapid Cycling Synchrotron (RCS) and Main Ring (MR), a unique magnetic alloy-loaded cavity is used for the beam acceleration and much higher field gradient has been achieved. Such high field gradient cavities made a compact RCS possible by reducing the length for beam acceleration. Now, further upgrades of the J-PARC, RF cavities with higher RF voltage and less power loss in the magnetic core are needed for the MR. For the improvements of the magnetic property of magnetic alloy core, the high temperature μSR (muon Spin Rotation/Relaxation) was used to investigate the crystallization process of the material. Based on the measurement results, the test production of the large ring cores of a magnetic alloy, FT3L, was tried. The FT3L is the magnetic alloy which has two times better performance than the present one, FT3M. For the FT3L production, the magnetic annealing is needed to control the easy-magnetized axis of the crystalline. After the success of the test production, a mass production was started in the industry to replace all existing cavities in the MR. The first 5-cell FT3L cavity is assembled for the bench test before the installation in the accelerator tunnel. By the new cavities, the total RF voltage of J-PARC MR will be doubled to increase the beam power for neutrino experiment. In future, the cavities will be also used for the RCS to increase the beam power beyond 1 MW.

  20. 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

  1. Subpanel on accelerator-based neutrino oscillation experiments

    SciTech Connect

    1995-09-01

    Neutrinos are among nature`s fundamental constituents, and they are also the ones about which we know least. Their role in the universe is widespread, ranging from the radioactive decay of a single atom to the explosions of supernovae and the formation of ordinary matter. Neutrinos might exhibit a striking property that has not yet been observed. Like the back-and-forth swing of a pendulum, neutrinos can oscillate to-and-from among their three types (or flavors) if nature provides certain conditions. These conditions include neutrinos having mass and a property called {open_quotes}mixing.{close_quotes} The phenomenon is referred to as neutrino oscillations. The questions of the origin of neutrino mass and mixing among the neutrino flavors are unsolved problems for which the Standard Model of particle physics holds few clues. It is likely that the next critical step in answering these questions will result from the experimental observation of neutrino oscillations. The High Energy Physics Advisory Panel (HEPAP) Subpanel on Accelerator-Based Neutrino Oscillation Experiments was charged to review the status and discovery potential of ongoing and proposed accelerator experiments on neutrino oscillations, to evaluate the opportunities for the U.S. in this area of physics, and to recommend a cost-effective plan for pursuing this physics, as appropriate. The complete charge is provided in Appendix A. The Subpanel studied these issues over several months and reviewed all the relevant and available information on the subject. In particular, the Subpanel reviewed the two proposed neutrino oscillation programs at Fermi National Accelerator Laboratory (Fermilab) and at Brookhaven National Laboratory (BNL). The conclusions of this review are enumerated in detail in Chapter 7 of this report. The recommendations given in Chapter 7 are also reproduced in this summary.

  2. Hyper-velocity impact experiments with electrostatic dust accelerators

    NASA Astrophysics Data System (ADS)

    Mocker, Anna; Aust, Thomas; Bugiel, Sebastian; Hillier, Jonathan; Hornung, Klaus; Li, Yan-Wei; Strack, Heiko; Ralf, Srama

    2015-06-01

    Hypervelocity impacts (HVI) of micrometer-sized particles play an important role in a variety of fields such as the investigation of matter at extreme pressures and temperatures, shock waves in solid bodies, planetology and cosmic dust. The physical phenomena occurring upon impact are fragmentation and cratering, shock waves, the production of neutral and ionized gas, and light flashes. Advanced analysis techniques promise new insights into short time-scale high-pressure states of matter, requiring the production of high speed projectiles. Electrostatic accelerators act as a source of micrometer and sub-micrometer particles as projectiles for HVI experiments. This paper describes an HVI facility, capable of accelerating particles to over 100 km/s, currently located at the Max Planck Institute for Nuclear Physics in Heidelberg, together with planned improvements. The facility is about to be relocated to the University of Stuttgart. This is an opportunity to enhance the facility to meet the requirements of future experimental campaigns, necessary to better understand the micrometeoroid hypervelocity impact process and develop new in situ dust experiments. We will present the design of the new facility and the planned enhancements, including new diagnostic apparatus.

  3. Aging and sleep in Williams syndrome: accelerated sleep deterioration and decelerated slow wave sleep decrement.

    PubMed

    Bódizs, Róbert; Gombos, Ferenc; Gerván, Patrícia; Szőcs, Katalin; Réthelyi, János M; Kovács, Ilona

    2014-12-01

    Specific developmental and aging trajectories characterize sleep electroencephalogram (EEG) of typically developing (TD) subjects. Williams syndrome (WS) is marked by sleep alterations and accelerated aging of several anatomo-functional and cognitive measures. Here we test the hypothesis of a premature aging of sleep in WS. Age-related changes of home recorded sleep EEG of 42 subjects (21 WS, 21 age- and gender matched TD subjects, age: 6-29 years) were tested by Pearson correlations and homogeneity-of-slopes analysis. Typical developmental/aging effects of sleep EEGs were observed in TD subjects. Accelerated aging in WS was confirmed by overall sleep/wake measures. Specifically, premature aging was evident in accelerated age-dependent declines in WS subjects' sleep efficiency, as well as in steeper age-related rises in wakefulness and wake after sleep onset (WASO) of the WS group. In contrast, NREM sleep-related measures indicated atypical decelerations of the developmental trends of WS subjects, characterized by the slowing down of the age-related slow wave sleep (SWS) declines mirrored by the lack of age-dependent increase in Stage 2 (S2) sleep. Age-effects in sleep EEG power spectra were not different among the groups. Objectively measured sleep disruption of subjects with WS is age-dependent and increasing with age. Moreover, these data suggest atypical pre- and postpubertal neural development in WS, with sleep/wake balance and REM sleep time indicating accelerated aging while NREM sleep composition revealing signs of an as yet unidentified, perhaps compensatory developmental delay. PMID:25178705

  4. 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

  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. Wakefield Simulations for the Laser Acceleration Experiment at SLAC

    SciTech Connect

    Ng, Johnny

    2012-04-18

    Laser-driven acceleration in dielectric photonic band gap structures can provide gradients on the order of GeV/m. The small transverse dimension of the structure, on the order of the laser wavelength, presents interesting wakefield-related issues. Higher order modes can seriously degrade beam quality, and a detailed understanding is needed to mitigate such effects. On the other hand, wakefields also provide a direct way to probe the interaction of a relativistic bunch with the synchronous modes supported by the structure. Simulation studies have been carried out as part of the effort to understand the impact on beam dynamics, and to compare with data from beam experiments designed to characterize candidate structures. In this paper, we present simulation results of wakefields excited by a sub-wavelength bunch in optical photonic band gap structures.

  7. Accelerating multidimensional NMR and MRI experiments using iterated maps

    NASA Astrophysics Data System (ADS)

    Barrett, Sean; Frey, Merideth; Sethna, Zachary; Manley, Gregory; Sengupta, Suvrajit; Zilm, Kurt; Loria, J. Patrick

    2014-03-01

    Techniques that accelerate data acquisition without sacrificing the advantages of fast Fourier transform (FFT) reconstruction could benefit a wide variety of magnetic resonance experiments. Here we discuss an approach for reconstructing multidimensional nuclear magnetic resonance (NMR) spectra and MR images from sparsely-sampled time domain data, by way of iterated maps. This method exploits the computational speed of the FFT algorithm and is done in a deterministic way, by reformulating any a priori knowledge or constraints into projections, and then iterating. In this paper we explain the motivation behind this approach, the formulation of the specific projections, the benefits of using a `QUasi-Even Sampling, plus jiTter' (QUEST) sampling schedule, and various methods for handling noise. Applying the iterated maps method to real 2D NMR and 3D MRI of solids data, we show that it is flexible and robust enough to handle large data sets with significant noise and artifacts.

  8. Accelerating multidimensional NMR and MRI experiments using iterated maps

    NASA Astrophysics Data System (ADS)

    Frey, Merideth A.; Sethna, Zachary M.; Manley, Gregory A.; Sengupta, Suvrajit; Zilm, Kurt W.; Loria, J. Patrick; Barrett, Sean E.

    2013-12-01

    Techniques that accelerate data acquisition without sacrificing the advantages of fast Fourier transform (FFT) reconstruction could benefit a wide variety of magnetic resonance experiments. Here we discuss an approach for reconstructing multidimensional nuclear magnetic resonance (NMR) spectra and MR images from sparsely-sampled time domain data, by way of iterated maps. This method exploits the computational speed of the FFT algorithm and is done in a deterministic way, by reformulating any a priori knowledge or constraints into projections, and then iterating. In this paper we explain the motivation behind this approach, the formulation of the specific projections, the benefits of using a ‘QUasi-Even Sampling, plus jiTter' (QUEST) sampling schedule, and various methods for handling noise. Applying the iterated maps method to real 2D NMR and 3D MRI of solids data, we show that it is flexible and robust enough to handle large data sets with significant noise and artifacts.

  9. 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.

  10. Accelerated ageing in testing bricks used in the conservation of historic buildings

    NASA Astrophysics Data System (ADS)

    Pavlendová, Gabriela; Podoba, Rudolf; Baník, Ivan

    2014-11-01

    The effect of accelerated climate ageing on historical bricks in the laboratory is investigated in the paper. Differences in thermal properties are experimentally determined and studied before and after bricks exposure to climate ageing, which consists of 60 freeze-thaw cycles. For measuring thermal conductivity, diffusivity and specific heat, pulse method is used.

  11. From the Discovery of Radioactivity to the First Accelerator Experiments

    NASA Astrophysics Data System (ADS)

    Walter, Michael

    The chapter reviews the historical phases of cosmic ray research from the very beginning around 1900 until the 1940s when first particle accelerators replaced cosmic particles as source for elementary particle interactions. In opposite to the discovery of X-rays or the ionising α-, β- and γ-rays, it was an arduous path to the definite acceptance of the new radiation. The starting point was the explanation that air becomes conductive by the ionising radiation of radioactive elements in the surroundings. In the following years the penetration power of the radiation was studied with the result, that there seems be a component harder than the known γ-rays. Victor F. Hess did in 1912 the key experiment with a hydrogen balloon. He measured with three detectors an increase of ionisation up to altitudes of 5 300 m and discovered the extraterrestrial penetrating radiation. The next phase is characterised by W. Kolhörster's confirmation in 1914, doubts by R.A. Millikan and others as well as the spectacular re-discovery of cosmic rays by Millikan in 1926. With the invention of new detectors as the cloud chamber and the Geiger-Müller counter and of the coincidence method the properties of cosmic rays could be investigated. One of the striking results was the discovery that cosmic rays are of corpuscular nature. The broad research activities starting end of the 1920s were the begin of a scientific success story, which nobody of the early protagonists might have imagined. In 1932 C.D. Anderson discovered the antiparticle of the electron. It was the birth of elementary particle physics. Four years later the muon was discovered which was for many years wrongly assumed to be the carrier of the short range nuclear force predicted by H. Yukawa. One of the last high-lights before the particle accelerators took over this field of fundamental research was the discovery of the Yukawa particle. In photographic emulsions exposed by cosmic particles the pion was found in 1947. This

  12. 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

  13. Operational experience on the Brookhaven National Laboratory Accelerator Test Facility

    SciTech Connect

    Batchelor, K.; Babzien, M.; Ben-Zvi, I.

    1994-09-01

    Brookhaven National Laboratory Accelerator Test Facility is a laser-electron linear accelerator complex designed to provide high brightness beams for testing of advanced acceleration concepts and high power pulsed photon sources. Results of electron beam parameters attained during the commissioning of the nominally 45 MeV energy machine are presented.

  14. 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

  15. Fine-pore aeration diffusers: accelerated membrane ageing studies.

    PubMed

    Kaliman, An; Rosso, Diego; Leu, Shao-Yuan; Stenstrom, Michael K

    2008-01-01

    Polymeric membranes are widely used in aeration systems for biological treatment. These membranes may degrade over time and are sensitive to fouling and scaling. Membrane degradation is reflected in a decline in operating performance and higher headloss, resulting in increased energy costs. Mechanical property parameters, such as membrane hardness, Young's modulus, and orifice creep, were used to characterize the performance of membranes over time in operation and to predict their failure. Used diffusers from municipal wastewater treatment plants were collected and tested for efficiency and headloss, and then dissected to facilitate measurements of Young's modulus, hardness, and orifice creep. Higher degree of membrane fouling corresponded consistently with larger orifice creep. A lab-scale membrane ageing simulation was performed with polyurethane and four different ethylene-propylene-diene (EPDM) membrane diffusers by subjecting them to chemical ageing cycles and periodic testing. The results confirmed full-scale plant results and showed the superiority of orifice creep over Young's modulus and hardness in predicting diffuser deterioration. PMID:17706264

  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. 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

  18. 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

  19. Proof-of-principle experiments of laser Wakefield acceleration

    SciTech Connect

    Nakajima, K.; Kawakubo, T.; Nakanishi, H.

    1994-04-01

    Recently there has been a great interest in laser-plasma accelerators as possible next-generation particle accelerators because of their potential for ultra high accelerating gradients and compact size compared with conventional accelerators. It is known that the laser pulse is capable of exciting a plasma wave propagating at a phase velocity close to the velocity of light by means of beating two-frequency lasers or an ultra short laser pulse. These schemes came to be known as the Beat Wave Accelerator (BWA) for beating lasers or as the Laser Wakefield Accelerator (LWFA) for a short pulse laser. In this paper, the principle of laser wakefield particle acceleration has been tested by the Nd:glass laser system providing a short pulse with a power of 10 TW and a duration of 1 ps. Electrons accelerated up to 18 MeV/c have been observed by injecting 1 MeV/c electrons emitted from a solid target by an intense laser impact. The accelerating field gradient of 30 GeV/m is inferred.

  20. Maladaptive autonomic regulation in PTSD accelerates physiological aging

    PubMed Central

    Williamson, John B.; Porges, Eric C.; Lamb, Damon G.; Porges, Stephen W.

    2015-01-01

    A core manifestation of post-traumatic stress disorder (PTSD) is a disconnection between physiological state and psychological or behavioral processes necessary to adequately respond to environmental demands. Patients with PTSD experience abnormal oscillations in autonomic states supporting either fight and flight behaviors or withdrawal, immobilization, and dissociation without an intervening “calm” state that would provide opportunities for positive social interactions. This defensive autonomic disposition is adaptive in dangerous and life threatening situations, but in the context of every-day life may lead to significant psychosocial distress and deteriorating social relationships. The perpetuation of these maladaptive autonomic responses may contribute to the development of comorbid mental health issues such as depression, loneliness, and hostility that further modify the nature of cardiovascular behavior in the context of internal and external stressors. Over time, changes in autonomic, endocrine, and immune function contribute to deteriorating health, which is potently expressed in brain dysfunction and cardiovascular disease. In this theoretical review paper, we present an overview of the literature on the chronic health effects of PTSD. We discuss the brain networks underlying PTSD in the context of autonomic efferent and afferent contributions and how disruption of these networks leads to poor health outcomes. Finally, we discuss treatment approaches based on our theoretical model of PTSD. PMID:25653631

  1. Isentropic compression experiments on the Sandia Z accelerator

    SciTech Connect

    HALL,CLINT A.

    2000-02-21

    A long-standing goal of the equation of state (EOS) community has been the development of a loading capability for direct measurement of material properties along an isentrope. Previous efforts on smooth bore launchers have been somewhat successful, but quite difficult to accurately reproduce, had pressure limitations, or tended to be a series of small shocks as opposed to a smoothly increasing pressure load. A technique has recently been developed on the Sandia National Laboratories Z accelerator which makes use of the high current densities and magnetic fields available to produce nearly isentropic compression of samples that are approximately 1 mm in thickness over approximately 120 ns. Velocity interferometry is used to measure the rear surface motion of these samples. The resulting time resolved velocity profiles from multiple sample thicknesses provide information about mechanical response under isentropic loading conditions and phase transition kinetics. Feasibility experiments have been performed to pressures of approximately 130 kbar in copper and 300 kbar in iron with effects of the {alpha}-{var_epsilon} phase change kinetics in iron clearly observed. Work is in progress to achieve 1--2% accuracy in P-v space along an isentrope, provide uniaxial strain, and to eliminate magnetic field and current diffusion within the sample of interest.

  2. p63 deficiency activates a program of cellular senescence and leads to accelerated aging

    PubMed Central

    Keyes, William M.; Wu, Ying; Vogel, Hannes; Guo, Xuecui; Lowe, Scott W.; Mills, Alea A.

    2005-01-01

    The p53 tumor suppressor plays a key role in organismal aging. A cellular mechanism postulated to drive the aging process is cellular senescence, mediated in part by p53. Although senescent cells accumulate in elderly individuals, most studies have relied on correlating in vitro senescence assays with in vivo phenotypes of aging. Here, using two different mouse models in which the p53-related protein p63 is compromised, we demonstrate that cellular senescence and organismal aging are intimately linked and that these processes are mediated by p63 loss. We found that p63+/- mice have a shortened life span and display features of accelerated aging. Both germline and somatically induced p63 deficiency activates widespread cellular senescence with enhanced expression of senescent markers SA-β-gal, PML, and p16INK4a. Using an inducible tissue-specific p63 conditional model, we further show that p63 deficiency induces cellular senescence and causes accelerated aging phenotypes in the adult. Our results thus suggest a causative link between cellular senescence and aging in vivo, and demonstrate that p63 deficiency accelerates this process. PMID:16107615

  3. 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.

  4. Coenzyme Q10 prevents accelerated cardiac aging in a rat model of poor maternal nutrition and accelerated postnatal growth.

    PubMed

    Tarry-Adkins, Jane L; Blackmore, Heather L; Martin-Gronert, Malgorzata S; Fernandez-Twinn, Denise S; McConnell, Josie M; Hargreaves, Iain P; Giussani, Dino A; Ozanne, Susan E

    2013-01-01

    Studies in human and animals have demonstrated that nutritionally induced low birth-weight followed by rapid postnatal growth increases the risk of metabolic syndrome and cardiovascular disease. Although the mechanisms underlying such nutritional programming are not clearly defined, increased oxidative-stress leading to accelerated cellular aging has been proposed to play an important role. Using an established rodent model of low birth-weight and catch-up growth, we show here that post-weaning dietary supplementation with coenzyme Q10, a key component of the electron transport chain and a potent antioxidant rescued many of the detrimental effects of nutritional programming on cardiac aging. This included a reduction in nitrosative and oxidative-stress, telomere shortening, DNA damage, cellular senescence and apoptosis. These findings demonstrate the potential for postnatal antioxidant intervention to reverse deleterious phenotypes of developmental programming and therefore provide insight into a potential translatable therapy to prevent cardiovascular disease in at risk humans. PMID:24327963

  5. Accelerated growth of calcium silicate hydrates: Experiments and simulations

    SciTech Connect

    Nicoleau, Luc

    2011-12-15

    Despite the usefulness of isothermal calorimetry in cement analytics, without any further computations this brings only little information on the nucleation and growth of hydrates. A model originally developed by Garrault et al. is used in this study in order to simulate hydration curves of cement obtained by calorimetry with different known hardening accelerators. The limited basis set of parameters used in this model, having a physical or chemical significance, is valuable for a better understanding of mechanisms underlying in the acceleration of C-S-H precipitation. Alite hydration in presence of four different types of hardening accelerators was investigated. It is evidenced that each accelerator type plays a specific role on one or several growth parameters and that the model may support the development of new accelerators. Those simulations supported by experimental observations enable us to follow the formation of the C-S-H layer around grains and to extract interesting information on its apparent permeability.

  6. Survivability of integrated PVDF film sensors to accelerated ageing conditions in aeronautical/aerospace structures

    NASA Astrophysics Data System (ADS)

    Guzman, E.; Cugnoni, J.; Gmür, T.; Bonhôte, P.; Schorderet, A.

    2013-06-01

    This work validates the use of integrated polyvinylidene fluoride (PVDF) film sensors for dynamic testing, even after being subjected to UV-thermo-hygro-mechanical accelerated ageing conditions. The verification of PVDF sensors’ survivability in these environmental conditions, typically confronted by civil and military aircraft, is the main concern of the study. The evaluation of survivability is made by a comparison of dynamic testing results provided by the PVDF patch sensors subjected to an accelerated ageing protocol, and those provided by neutral non-aged sensors (accelerometers). The available measurements are the time-domain response signals issued from a modal analysis procedure, and the corresponding frequency response functions (FRF). These are in turn used to identify the constitutive properties of the samples by extraction of the modal parameters, in particular the natural frequencies. The composite specimens in this study undergo different accelerated ageing processes. After several weeks of experimentation, the samples exhibit a loss of stiffness, represented by a decrease in the elastic moduli down to 10%. Despite the ageing, the integrated PVDF sensors, subjected to the same ageing conditions, are still capable of providing reliable data to carry out a close followup of these changes. This survivability is a determinant asset in order to use integrated PVDF sensors to perform structural health monitoring (SHM) in the future of full-scale composite aeronautical structures.

  7. Interaction of accelerated aging and p-coumaric acid on crimson clover seed germination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several phenolic acids, including p-coumaric acid, have been described as allelochemicals that may inhibit seed germination or seedling growth. Accelerated seed aging (high temperature (41 C) and high humidity (100%)) reduces germination and seedling vigor, and provides some indication as to seed g...

  8. Effects of accelerated aging and p-coumaric on crimson clover (Trifolium incarnatium L.) seed germination.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several phenolic acids, including p-coumaric acid, have been described as allelochemicals that may inhibit seed germination or seedling growth. Whether these effects are exacerbated in forage species by environmental stressors is unknown. Accelerated seed aging (high temperature (41 C) and high hum...

  9. Accelerated Vascular Aging as a Paradigm for Hypertensive Vascular Disease: Prevention and Therapy.

    PubMed

    Barton, Matthias; Husmann, Marc; Meyer, Matthias R

    2016-05-01

    Aging is considered the most important nonmodifiable risk factor for cardiovascular disease and death after age 28 years. Because of demographic changes the world population is expected to increase to 9 billion by the year 2050 and up to 12 billion by 2100, with several-fold increases among those 65 years of age and older. Healthy aging and prevention of aging-related diseases and associated health costs have become part of political agendas of governments around the world. Atherosclerotic vascular burden increases with age; accordingly, patients with progeria (premature aging) syndromes die from myocardial infarctions or stroke as teenagers or young adults. The incidence and prevalence of arterial hypertension also increases with age. Arterial hypertension-like diabetes and chronic renal failure-shares numerous pathologies and underlying mechanisms with the vascular aging process. In this article, we review how arterial hypertension resembles premature vascular aging, including the mechanisms by which arterial hypertension (as well as other risk factors such as diabetes mellitus, dyslipidemia, or chronic renal failure) accelerates the vascular aging process. We will also address the importance of cardiovascular risk factor control-including antihypertensive therapy-as a powerful intervention to interfere with premature vascular aging to reduce the age-associated prevalence of diseases such as myocardial infarction, heart failure, hypertensive nephropathy, and vascular dementia due to cerebrovascular disease. Finally, we will discuss the implementation of endothelial therapy, which aims at active patient participation to improve primary and secondary prevention of cardiovascular disease. PMID:27118295

  10. Down syndrome as a model of DNA polymerase beta haploinsufficiency and accelerated aging.

    PubMed

    Patterson, David; Cabelof, Diane C

    2012-04-01

    Down syndrome is a condition of intellectual disability characterized by accelerated aging. As with other aging syndromes, evidence accumulated over the past several decades points to a DNA repair defect inherent in Down syndrome. This evidence has led us to suggest that Down syndrome results in reduced DNA base excision repair (BER) capacity, and that this contributes to the genomic instability and the aging phenotype of Down syndrome. We propose important roles for microRNA and/or folate metabolism and oxidative stress in the dysregulation of BER in Down syndrome. Further, we suggest these pathways are involved in the leukemogenesis of Down syndrome. We have reviewed the role of BER in the processing of oxidative stress, and the impact of folate depletion on BER capacity. Further, we have reviewed the role that loss of BER, specifically DNA polymerase beta, plays in accelerating the rate of aging. Like that seen in the DNA polymerase beta heterozygous mouse, the aging phenotype of Down syndrome is subtle, unlike the aging phenotypes seen in the classical progeroid syndromes and mouse models of aging. As such, Down syndrome may provide a model for elucidating some of the basic mechanisms of aging. PMID:22019846

  11. 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.

  12. 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.

  13. AWAKE, The Advanced Proton Driven Plasma Wakefield Acceleration Experiment at CERN

    NASA Astrophysics Data System (ADS)

    Gschwendtner, E.; Adli, E.; Amorim, L.; Apsimon, R.; Assmann, R.; Bachmann, A.-M.; Batsch, F.; Bauche, J.; Berglyd Olsen, V. K.; Bernardini, M.; Bingham, R.; Biskup, B.; Bohl, T.; Bracco, C.; Burrows, P. N.; Burt, G.; Buttenschön, B.; Butterworth, A.; Caldwell, A.; Cascella, M.; Chevallay, E.; Cipiccia, S.; Damerau, H.; Deacon, L.; Dirksen, P.; Doebert, S.; Dorda, U.; Farmer, J.; Fedosseev, V.; Feldbaumer, E.; Fiorito, R.; Fonseca, R.; Friebel, F.; Gorn, A. A.; Grulke, O.; Hansen, J.; Hessler, C.; Hofle, W.; Holloway, J.; Hüther, M.; Jaroszynski, D.; Jensen, L.; Jolly, S.; Joulaei, A.; Kasim, M.; Keeble, F.; Li, Y.; Liu, S.; Lopes, N.; Lotov, K. V.; Mandry, S.; Martorelli, R.; Martyanov, M.; Mazzoni, S.; Mete, O.; Minakov, V. A.; Mitchell, J.; Moody, J.; Muggli, P.; Najmudin, Z.; Norreys, P.; Öz, E.; Pardons, A.; Pepitone, K.; Petrenko, A.; Plyushchev, G.; Pukhov, A.; Rieger, K.; Ruhl, H.; Salveter, F.; Savard, N.; Schmidt, J.; Seryi, A.; Shaposhnikova, E.; Sheng, Z. M.; Sherwood, P.; Silva, L.; Soby, L.; Sosedkin, A. P.; Spitsyn, R. I.; Trines, R.; Tuev, P. V.; Turner, M.; Verzilov, V.; Vieira, J.; Vincke, H.; Wei, Y.; Welsch, C. P.; Wing, M.; Xia, G.; Zhang, H.

    2016-09-01

    The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) aims at studying plasma wakefield generation and electron acceleration driven by proton bunches. It is a proof-of-principle R&D experiment at CERN and the world's first proton driven plasma wakefield acceleration experiment. The AWAKE experiment will be installed in the former CNGS facility and uses the 400 GeV/c proton beam bunches from the SPS. The first experiments will focus on the self-modulation instability of the long (rms ~12 cm) proton bunch in the plasma. These experiments are planned for the end of 2016. Later, in 2017/2018, low energy (~15 MeV) electrons will be externally injected into the sample wakefields and be accelerated beyond 1 GeV. The main goals of the experiment will be summarized. A summary of the AWAKE design and construction status will be presented.

  14. Acceleration units for the Induction Linac Systems Experiment (ILSE)

    SciTech Connect

    Faltens, A.; Brady, V.; Brodzik, D.; Hansen, L.; Laslett, L.J.; Mukherjee, S.; Bubp, D.; Ravenscroft, D.; Reginato, L.

    1989-03-01

    The design of a high current heavy ion induction linac driver for inertial confinement fusion is optimized by adjusting the acceleration units along the length of the accelerator to match the beam current, energy, and pulse duration at any location. At the low energy end of the machine the optimum is a large number of electrostatically focused parallel beamlets, whereas at higher energies the optimum is a smaller number of magnetically focused beams. ILSE parallels this strategy by using 16 electrostatically focused beamlets at the low end followed by 4 magnetically focused beams after beam combining. 3 refs., 2 figs.

  15. [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

  16. Obesity-induced oxidative stress, accelerated functional decline with age and increased mortality in mice

    PubMed Central

    Zhang, Yiqiang; Fischer, Kathleen E.; Soto, Vanessa; Liu, Yuhong; Sosnowska, Danuta; Richardson, Arlan; Salmon, Adam B.

    2015-01-01

    Obesity is a serious chronic disease that increases the risk of numerous co-morbidities including metabolic syndrome, cardiovascular disease and cancer as well as increases risk of mortality leading some to suggest this represents accelerated aging. Obesity is associated with significant increases in oxidative stress in vivo and, despite the well-explored relationship between oxidative stress and aging, the role this plays in the increased mortality of obese subjects remains an unanswered question. Here, we addressed this by undertaking a comprehensive, longitudinal study of a group of high fat-fed obese mice and assessed both their changes in oxidative stress and in their performance in physiological assays known to decline with aging. In female C57BL/6J mice fed a high-fat diet starting in adulthood, mortality was significantly increased in high fat-fed mice as was oxidative damage in vivo. High fat-feeding significantly accelerated the decline in performance in several assays, including activity, gait, and rotarod. However, we also found that obesity had little effect on other markers and actually improved performance in grip strength, a marker of muscular function. Together, this first comprehensive assessment of longitudinal functional changes in high fat-fed mice suggests that obesity may induce segmental acceleration of some of the aging process. PMID:25558793

  17. Body Acceleration as Indicator for Walking Economy in an Ageing Population

    PubMed Central

    Valenti, Giulio; Bonomi, Alberto G.; Westerterp, Klaas R.

    2015-01-01

    Background In adults, walking economy declines with increasing age and negatively influences walking speed. This study aims at detecting determinants of walking economy from body acceleration during walking in an ageing population. Methods 35 healthy elderly (18 males, age 51 to 83 y, BMI 25.5±2.4 kg/m2) walked on a treadmill. Energy expenditure was measured with indirect calorimetry while body acceleration was sampled at 60Hz with a tri-axial accelerometer (GT3X+, ActiGraph), positioned on the lower back. Walking economy was measured as lowest energy needed to displace one kilogram of body mass for one meter while walking (WCostmin, J/m/kg). Gait features were extracted from the acceleration signal and included in a model to predict WCostmin. Results On average WCostmin was 2.43±0.42 J/m/kg and correlated significantly with gait rate (r2 = 0.21, p<0.01) and regularity along the frontal (anteroposterior) and lateral (mediolateral) axes (r2 = 0.16, p<0.05 and r2 = 0.12, p<0.05 respectively). Together, the three variables explained 46% of the inter-subject variance (p<0.001) with a standard error of estimate of 0.30 J/m/kg. WCostmin and regularity along the frontal and lateral axes were related to age (WCostmin: r2 = 0.44, p<0.001; regularity: r2 = 0.16, p<0.05 and r2 = 0.12, p<0.05 respectively frontal and lateral). Conclusions The age associated decline in walking economy is induced by the adoption of an increased gait rate and by irregular body acceleration in the horizontal plane. PMID:26512982

  18. Accelerated brain aging in schizophrenia and beyond: a neuroanatomical marker of psychiatric disorders.

    PubMed

    Koutsouleris, Nikolaos; Davatzikos, Christos; Borgwardt, Stefan; Gaser, Christian; Bottlender, Ronald; Frodl, Thomas; Falkai, Peter; Riecher-Rössler, Anita; Möller, Hans-Jürgen; Reiser, Maximilian; Pantelis, Christos; Meisenzahl, Eva

    2014-09-01

    Structural brain abnormalities are central to schizophrenia (SZ), but it remains unknown whether they are linked to dysmaturational processes crossing diagnostic boundaries, aggravating across disease stages, and driving the neurodiagnostic signature of the illness. Therefore, we investigated whether patients with SZ (N = 141), major depression (MD; N = 104), borderline personality disorder (BPD; N = 57), and individuals in at-risk mental states for psychosis (ARMS; N = 89) deviated from the trajectory of normal brain maturation. This deviation was measured as difference between chronological and the neuroanatomical age (brain age gap estimation [BrainAGE]). Neuroanatomical age was determined by a machine learning system trained to individually estimate age from the structural magnetic resonance imagings of 800 healthy controls. Group-level analyses showed that BrainAGE was highest in SZ (+5.5 y) group, followed by MD (+4.0), BPD (+3.1), and the ARMS (+1.7) groups. Earlier disease onset in MD and BPD groups correlated with more pronounced BrainAGE, reaching effect sizes of the SZ group. Second, BrainAGE increased across at-risk, recent onset, and recurrent states of SZ. Finally, BrainAGE predicted both patient status as well as negative and disorganized symptoms. These findings suggest that an individually quantifiable "accelerated aging" effect may particularly impact on the neuroanatomical signature of SZ but may extend also to other mental disorders. PMID:24126515

  19. Arsenite exposure accelerates aging process regulated by the transcription factor DAF-16/FOXO in Caenorhabditis elegans.

    PubMed

    Yu, Chan-Wei; How, Chun Ming; Liao, Vivian Hsiu-Chuan

    2016-05-01

    Arsenic is a known human carcinogen and high levels of arsenic contamination in food, soils, water, and air are of toxicology concerns. Nowadays, arsenic is still a contaminant of emerging interest, yet the effects of arsenic on aging process have received little attention. In this study, we investigated the effects and the underlying mechanisms of chronic arsenite exposure on the aging process in Caenorhabditis elegans. The results showed that prolonged arsenite exposure caused significantly decreased lifespan compared to non-exposed ones. In addition, arsenite exposure (100 μM) caused significant changes of age-dependent biomarkers, including a decrease of defecation frequency, accumulations of intestinal lipofuscin and lipid peroxidation in an age-dependent manner in C. elegans. Further evidence revealed that intracellular reactive oxygen species (ROS) level was significantly increased in an age-dependent manner upon 100 μM arsenite exposure. Moreover, the mRNA levels of transcriptional makers of aging (hsp-16.1, hsp-16.49, and hsp-70) were increased in aged worms under arsenite exposure (100 μM). Finally, we showed that daf-16 mutant worms were more sensitive to arsenite exposure (100 μM) on lifespan and failed to induce the expression of its target gene sod-3 in aged daf-16 mutant under arsenite exposure (100 μM). Our study demonstrated that chronic arsenite exposure resulted in accelerated aging process in C. elegans. The overproduction of intracellular ROS and the transcription factor DAF-16/FOXO play roles in mediating the accelerated aging process by arsenite exposure in C. elegans. This study implicates a potential ecotoxicological and health risk of arsenic in the environment. PMID:26796881

  20. 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

  1. Two-Channel Rectangular Dielectric Wake Field Accelerator Structure Experiment

    SciTech Connect

    Sotnikov, G. V.; Marshall, T. C.; Shchelkunov, S. V.; Didenko, A.; Hirshfield, J. L.

    2009-01-22

    A design is presented for a two-channel 30-GHz rectangular dielectric wake field accelerator structure being built for experimental tests at Argonne National Laboratory (ANL). This structure allows for a transformer ratio T much greater than two, and permits continuous coupling of energy from drive bunches to accelerated bunches. It consists of three planar slabs of cordierite ceramic ({epsilon} = 4.7) supported within a rectangular copper block, forming a drive channel 12 mmx6 mm, and an accelerator channel 2 mmx6 mm. When driven by a 50 nC, 14 MeV single bunch available at ANL, theory predicts an acceleration field of 6 MeV/m, and T = 12.6. Inherent transverse wake forces introduce deflections and some distortion of bunch profiles during transit through the structure that are estimated to be tolerable. Additionally, a cylindrical two-channel DWFA is introduced which shares many advantages of the rectangular structure including high T, and the added virtue of axisymmetry that eliminates lowest-order transverse deflecting forces.

  2. RF ACCELERATING STRUCTURE FOR THE MUON COOLING EXPERIMENT.

    SciTech Connect

    CORLETT,J.; GREEN,M.; LI,D.; HOLTKAMP,N.; MORETTI,A.; KIRK,H.G.; PALMER,R.B.; ZHAO,Y.; SUMMERS,D.

    1999-03-29

    The ionization cooling of muons requires longitudinal acceleration of the muons after scattering in a hydrogen target. In order to maximize the accelerating voltage, we propose using linear accelerating structures with cells bounded by thin beryllium metal foils. This produces an on-axis field equivalent to the maximum surface field, whereas with beam-pipes the accelerating field is approximately half that of the peak surface field in the cavity. The muons interact only weakly with the thin foils. A {pi}/2 interleaved cavity structure has been chosen, with alternate cells coupled together externally, and the two groups of cells fed in quadrature. At present they are considering an operating temperature of 77K to gain a factor of at least two in Q-value over room temperature. The authors describe the design of the {pi}/2 interleaved cavity structure, design of an alternative {pi}-mode open structure, preliminary experimental results from a low-power test cavity, and plans for high-power testing.

  3. Present and future high-energy accelerators for neutrino experiments

    SciTech Connect

    Kourbanis, I.; /Fermilab

    2007-06-01

    There is an active neutrino program making use of the high-energy (larger than 50 GeV) accelerators both in USA at Fermilab with NuMI and at CERN in Europe with CNGS. In this paper we will review the prospects for high intensity high energy beams in those two locations during the next decade.

  4. Stability through the ages: the GSK experience.

    PubMed

    Blaxill, Zoe; Holland-Crimmin, Sue; Lifely, Rob

    2009-06-01

    It is common knowledge in the pharmaceutical industry that the quality of a company's compound collection has a major influence on the success of biological screening in drug discovery programs. DMSO is the widely accepted solvent of choice for storage of compounds, despite the hygroscopic nature of the solvent, which can lead to stability issues. Other factors that can affect compound stability (e.g., degradation, precipitation) include concentration of compound, intrinsic compound stability, presence of reactive contaminants, storage format-related factors (vessel, sealing, etc.), storage conditions (temperature, humidity, freeze-thaw technique and cycles, etc.), and storage time. To define the best practice for the storage and handling of solution samples, GlaxoSmithKline has undertaken stability experiments over more than a decade, initially to support the implementation of new automated liquid stores (ALS) and, subsequently, to enhance storage and use of compounds in solution through an understanding of compound degradation under storage and assay conditions. The experiments described used a number of technologies, including hyphenated liquid chromatography, electrospray mass spectrometry, flow chemiluminescence nitrogen detection, nuclear magnetic resonance, and Karl Fischer titration. PMID:19470717

  5. Models of Accelerated Sarcopenia: Critical Pieces for Solving the Puzzle of Age-Related Muscle Atrophy

    PubMed Central

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

    2013-01-01

    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. PMID:20438881

  6. 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

  7. Accelerated Brain Aging in Schizophrenia and Beyond: A Neuroanatomical Marker of Psychiatric Disorders

    PubMed Central

    Koutsouleris, Nikolaos; Davatzikos, Christos; Borgwardt, Stefan; Gaser, Christian; Bottlender, Ronald; Frodl, Thomas; Falkai, Peter; Riecher-Rössler, Anita; Möller, Hans-Jürgen; Reiser, Maximilian; Pantelis, Christos; Meisenzahl, Eva

    2014-01-01

    Structural brain abnormalities are central to schizophrenia (SZ), but it remains unknown whether they are linked to dysmaturational processes crossing diagnostic boundaries, aggravating across disease stages, and driving the neurodiagnostic signature of the illness. Therefore, we investigated whether patients with SZ (N = 141), major depression (MD; N = 104), borderline personality disorder (BPD; N = 57), and individuals in at-risk mental states for psychosis (ARMS; N = 89) deviated from the trajectory of normal brain maturation. This deviation was measured as difference between chronological and the neuroanatomical age (brain age gap estimation [BrainAGE]). Neuroanatomical age was determined by a machine learning system trained to individually estimate age from the structural magnetic resonance imagings of 800 healthy controls. Group-level analyses showed that BrainAGE was highest in SZ (+5.5 y) group, followed by MD (+4.0), BPD (+3.1), and the ARMS (+1.7) groups. Earlier disease onset in MD and BPD groups correlated with more pronounced BrainAGE, reaching effect sizes of the SZ group. Second, BrainAGE increased across at-risk, recent onset, and recurrent states of SZ. Finally, BrainAGE predicted both patient status as well as negative and disorganized symptoms. These findings suggest that an individually quantifiable “accelerated aging” effect may particularly impact on the neuroanatomical signature of SZ but may extend also to other mental disorders. PMID:24126515

  8. Influence of the humidity on leakage current under accelerated aging of polymer insulating materials

    SciTech Connect

    Otsubo, M.; Shimono, Y.; Hikami, T.; Honda, C.

    1996-12-31

    This paper describes the experimental results of accelerated aging tests conducted on three different types of polymer materials. Salt fog chamber tests were used to study the surface degradation modes for all materials. The work presented here was performed using a newly constructed fog chamber system that was able to control both chamber humidity and UV radiation. The changes in the surface morphology, material structure and leakage current were examined to study the influence of environmental humidity.

  9. 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.

  10. 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

  11. Real-Time Data from the Orbital Acceleration Research Experiment (OARE)

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The objective of the Orbital Acceleration Research Experiment (OARE) is to measure, with high accuracy, the low-frequency, low-magnitude acceleration levels onboard the space shuttle. The shuttle experiences acceleration from atmospheric drag, gravity gradient forces, shuttle rotations, crew activities, water/waste dumps, and shuttle attitude thrusters. The OARE instrument has successfully flown on five past shuttle missions and is scheduled for five upcoming microgravity science missions. The data collected by OARE will be utilized by microgravity scientists to better predict and analyze the influence and effects of the shuttle's on-orbit microgravity environment on experiments in materials, combustion, and fluids research.

  12. Intrauterine growth restriction programs an accelerated age-related increase in cardiovascular risk in male offspring.

    PubMed

    Dasinger, John Henry; Intapad, Suttira; Backstrom, Miles A; Carter, Anthony J; Alexander, Barbara T

    2016-08-01

    Placental insufficiency programs an increase in blood pressure associated with a twofold increase in serum testosterone in male growth-restricted offspring at 4 mo of age. Population studies indicate that the inverse relationship between birth weight and blood pressure is amplified with age. Thus, we tested the hypothesis that intrauterine growth restriction programs an age-related increase in blood pressure in male offspring. Growth-restricted offspring retained a significantly higher blood pressure at 12 but not at 18 mo of age compared with age-matched controls. Blood pressure was significantly increased in control offspring at 18 mo of age relative to control counterparts at 12 mo; however, blood pressure was not increased in growth-restricted at 18 mo relative to growth-restricted counterparts at 12 mo. Serum testosterone levels were not elevated in growth-restricted offspring relative to control at 12 mo of age. Thus, male growth-restricted offspring no longer exhibited a positive association between blood pressure and testosterone at 12 mo of age. Unlike hypertension in male growth-restricted offspring at 4 mo of age, inhibition of the renin-angiotensin system with enalapril (250 mg/l for 2 wk) did not abolish the difference in blood pressure in growth-restricted offspring relative to control counterparts at 12 mo of age. Therefore, these data suggest that intrauterine growth restriction programs an accelerated age-related increase in blood pressure in growth-restricted offspring. Furthermore, this study suggests that the etiology of increased blood pressure in male growth-restricted offspring at 12 mo of age differs from that at 4 mo of age. PMID:27147668

  13. 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. PMID:24922996

  14. Chromatic stability of acrylic resins of artificial eyes submitted to accelerated aging and polishing

    PubMed Central

    GOIATO, Marcelo Coelho; dos SANTOS, Daniela Micheline; SOUZA, Josiene Firmino; MORENO, Amália; PESQUEIRA, Aldiéris Alves

    2010-01-01

    Esthetics and durability of materials used to fabricate artificial eyes has been an important eissue since artificial eyes are essential to restore esthetics and function, protect the remaining tissues and help with patients' psychological therapy. However, these materials are submitted to degrading effects of environmental agents on the physical properties of the acrylic resin. Objective This study assessed the color stability of acrylic resins used to fabricate sclera in three basic shades (N1, N2 and N3) when subjected to accelerated aging, mechanical and chemical polishing. Material and methods Specimens of each resin were fabricated and submitted to mechanical and chemical polishing. Chromatic analysis was performed before and after accelerated aging through ultraviolet reflection spectrophotometry. Results All specimens revealed color alteration following polishing and accelerated aging. The resins presented statistically significant chromatic alteration (p<0.01) between the periods of 252 and 1008 h. Conclusions Both polishing methods presented no significant difference between the values of color derivatives of resins. PMID:21308298

  15. 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

  16. 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

  17. 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.

  18. Space Experiments with Particle Accelerators: SEPAC - SEPAC program for First Spacelab Mission

    NASA Astrophysics Data System (ADS)

    Obayashi, T.

    The Space Shuttle/Spacelab Mission Space Experiment with Particle Accelerators (SEPAC) will carry out interactive experiments on, and in, the earth ionosphere and magnetosphere, and comprises an electron beam accelerator, MPD arcjet, and associated diagnostic equipment. The mission Payload Specialist will be responsible for (1) manual control of scientific instruments, (2) monitoring of experiment displays, (3) restructuring of experiment sequence by means of display system keyboard, (4) safety and emergency operations, and (5) voice communications. Attention is given to the configurational and sequential organization of the SEPAC experiments.

  19. Experience in using FlexCtrl SCADA for accelerator automation

    NASA Astrophysics Data System (ADS)

    Nikiforov, A.; Aleinikov, V.; Sychev, A.; Borina, I.; Rukavishnikov, A.

    2012-07-01

    The programmed component of the automatic control of accelerators on the basis of licensed software packages (FlexCtrl SCADA, Photon Application Builder, and Cogent DataHub) and an additionally developed library of classes (related to visual programming with regard to functional capabilities and which all together represent an integrated media for producing the automation system) is described in the article. The number of features of the media components and the number of the components themselves can be increased since the developed media is characterized as open.

  20. Second-order state estimation experiments using acceleration measurements

    NASA Technical Reports Server (NTRS)

    Belvin, W. K.

    1992-01-01

    The estimation of dynamic states for feedback control of structural systems using second-order differential equations and acceleration measurements is described. The formulation of the observer model, and the design of the observer gains is discussed in detail. It is shown the second-order observer is highly stable because the stability constraints on the observer gains are model independent. The limitation of the proposed observer is the need for 'nearly' collocated actuators and accelerometers. Experimental results using a control-structure interaction testbed are presented that show the second-order observer provided more stability than a Kalman filter estimator without decreasing closed-loop performance.

  1. 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.

  2. Poetry Efforts by Aged Deaf: Expression of Life Cycle Experience.

    ERIC Educational Resources Information Center

    Wax, Teena M.

    1983-01-01

    Describes a day-long Aging Awareness workshop in which a group of 12 elderly were involved in a poetry-writing exercise focusing on meaningful life change. Ramifications of this positive experience are discussed in view of the cultural/language barrier and traditional aging awareness issues such as reminiscence. (JAC)

  3. Atherosclerosis in ancient humans, accelerated aging syndromes and normal aging: is lamin a protein a common link?

    PubMed

    Miyamoto, Michael I; Djabali, Karima; Gordon, Leslie B

    2014-06-01

    Imaging studies of ancient human mummies have demonstrated the presence of vascular calcification that is consistent with the presence of atherosclerosis. These findings have stimulated interest in the underlying biological processes that might impart to humans an inherent predisposition to the development of atherosclerosis. Clues to these processes may possibly be found in accelerated aging syndromes, such as Hutchinson-Gilford progeria syndrome (HGPS), an ultra-rare disorder characterized by premature aging phenotypes, including very aggressive forms of atherosclerosis, occurring in childhood. The genetic defect in HGPS eventuates in the production of a mutant form of the nuclear structural protein lamin A, called progerin, which is thought to interfere with normal nuclear functioning. Progerin appears to be expressed in vascular cells, resulting in vessel wall cell loss and replacement by fibrous tissue, reducing vessel compliance and promoting calcification, leading to the vascular dysfunction and atherosclerosis seen in HGPS. Interestingly, vascular progerin is detectable in lower levels, in an age-related manner, in the general population, providing the basis for further study of the potential role of abnormal forms of lamin A in the atherosclerotic process of normal aging. PMID:25667091

  4. Increased Oxidative and Nitrative Stress Accelerates Aging of the Retinal Vasculature in the Diabetic Retina

    PubMed Central

    Lamoke, Folami; Shaw, Sean; Yuan, Jianghe; Ananth, Sudha; Duncan, Michael; Martin, Pamela; Bartoli, Manuela

    2015-01-01

    Hyperglycemia-induced retinal oxidative and nitrative stress can accelerate vascular cell aging, which may lead to vascular dysfunction as seen in diabetes. There is no information on whether this may contribute to the progression of diabetic retinopathy (DR). In this study, we have assessed the occurrence of senescence-associated markers in retinas of streptozotocin-induced diabetic rats at 8 and 12 weeks of hyperglycemia as compared to normoglycemic aging (12 and 14 months) and adult (4.5 months) rat retinas. We have found that in the diabetic retinas there was an up-regulation of senescence-associated markers SA-β-Gal, p16INK4a and miR34a, which correlated with decreased expression of SIRT1, a target of miR34a. Expression of senescence-associated factors primarily found in retinal microvasculature of diabetic rats exceeded levels measured in adult and aging rat retinas. In aging rats, retinal expression of senescence associated-factors was mainly localized at the level of the retinal pigmented epithelium and only minimally in the retinal microvasculature. The expression of oxidative/nitrative stress markers such as 4-hydroxynonenal and nitrotyrosine was more pronounced in the retinal vasculature of diabetic rats as compared to normoglycemic aging and adult rat retinas. Treatments of STZ-rats with the anti-nitrating drug FeTPPS (10mg/Kg/day) significantly reduced the appearance of senescence markers in the retinal microvasculature. Our results demonstrate that hyperglycemia accelerates retinal microvascular cell aging whereas physiological aging affects primarily cells of the retinal pigmented epithelium. In conclusion, hyperglycemia-induced retinal vessel dysfunction and DR progression involve vascular cell senescence due to increased oxidative/nitrative stress. PMID:26466127

  5. Early-life stress and reproductive cost: A two-hit developmental model of accelerated aging?

    PubMed

    Shalev, Idan; Belsky, Jay

    2016-05-01

    Two seemingly independent bodies of research suggest a two-hit model of accelerated aging, one highlighting early-life stress and the other reproduction. The first, informed by developmental models of early-life stress, highlights reduced longevity effects of early adversity on telomere erosion, whereas the second, informed by evolutionary theories of aging, highlights such effects with regard to reproductive cost (in females). The fact that both early-life adversity and reproductive effort are associated with shorter telomeres and increased oxidative stress raises the prospect, consistent with life-history theory, that these two theoretical frameworks currently informing much research are tapping into the same evolutionary-developmental process of increased senescence and reduced longevity. Here we propose a mechanistic view of a two-hit model of accelerated aging in human females through (a) early-life adversity and (b) early reproduction, via a process of telomere erosion, while highlighting mediating biological embedding mechanisms that might link these two developmental aging processes. PMID:27063083

  6. Accelerated Aging during Chronic Oxidative Stress: A Role for PARP-1

    PubMed Central

    Boesten, Daniëlle M. P. H. J.; de Vos-Houben, Joyce M. J.; Timmermans, Leen; den Hartog, Gertjan J. M.; Bast, Aalt; Hageman, Geja J.

    2013-01-01

    Oxidative stress plays a major role in the pathophysiology of chronic inflammatory disease and it has also been linked to accelerated telomere shortening. Telomeres are specialized structures at the ends of linear chromosomes that protect these ends from degradation and fusion. Telomeres shorten with each cell division eventually leading to cellular senescence. Research has shown that poly(ADP-ribose) polymerase-1 (PARP-1) and subtelomeric methylation play a role in telomere stability. We hypothesized that PARP-1 plays a role in accelerated aging in chronic inflammatory diseases due to its role as coactivator of NF-κb and AP-1. Therefore we evaluated the effect of chronic PARP-1 inhibition (by fisetin and minocycline) in human fibroblasts (HF) cultured under normal conditions and under conditions of chronic oxidative stress, induced by tert-butyl hydroperoxide (t-BHP). Results showed that PARP-1 inhibition under normal culturing conditions accelerated the rate of telomere shortening. However, under conditions of chronic oxidative stress, PARP-1 inhibition did not show accelerated telomere shortening. We also observed a strong correlation between telomere length and subtelomeric methylation status of HF cells. We conclude that chronic PARP-1 inhibition appears to be beneficial in conditions of chronic oxidative stress but may be detrimental under relatively normal conditions. PMID:24319532

  7. Age-accelerated atherosclerosis correlates with failure to upregulate antioxidant genes.

    PubMed

    Collins, Alan R; Lyon, Christopher J; Xia, Xuefeng; Liu, Joey Z; Tangirala, Rajendra K; Yin, Fen; Boyadjian, Rima; Bikineyeva, Alfiya; Praticò, Domenico; Harrison, David G; Hsueh, Willa A

    2009-03-27

    Excess food intake leads to obesity and diabetes, both of which are well-known independent risk factors for atherosclerosis, and both of which are growing epidemics in an aging population. We hypothesized that aging enhances the metabolic and vascular effects of high fat diet (HFD) and therefore examined the effect of age on atherosclerosis and insulin resistance in lipoprotein receptor knockout (LDLR(-/-)) mice. We found that 12-month-old (middle-aged) LDLR(-/-) mice developed substantially worse metabolic syndrome, diabetes, and atherosclerosis than 3-month-old (young) LDLR(-/-) mice when both were fed HFD for 3 months, despite similar elevations in total cholesterol levels. Microarray analyses were performed to analyze the mechanism responsible for the marked acceleration of atherosclerosis in middle-aged mice. Chow-fed middle-aged mice had greater aortic expression of multiple antioxidant genes than chow-fed young mice, including glutathione peroxidase-1 and -4, catalase, superoxide dismutase-2, and uncoupling protein-2. Aortic expression of these enzymes markedly increased in young mice fed HFD but decreased or only modestly increased in middle-aged mice fed HFD, despite the fact that systemic oxidative stress and vascular reactive oxygen species generation, measured by plasma F2alpha isoprostane concentration (systemic) and dihydroethidium conversion and p47phox expression (vascular), were greater in middle-aged mice fed HFD. Thus, the mechanism for the accelerated vascular injury in older LDLR(-/-) mice was likely the profound inability to mount an antioxidant response. This effect was related to a decrease in vascular expression of 2 key transcriptional pathways regulating the antioxidant response, DJ-1 and forkhead box, subgroup O family (FOXOs). Treatment of middle-aged mice fed HFD with the antioxidant apocynin attenuated atherosclerosis, whereas treatment with the insulin sensitizer rosiglitazone attenuated both metabolic syndrome and atherosclerosis

  8. Numerical and Experimental Investigation of the Effects of Acceleration Disturbances on Microgravity Experiments

    NASA Technical Reports Server (NTRS)

    Ramachandran, Narayanan

    2000-01-01

    Normal vibrational modes on large spacecraft are excited by crew activity, operating machinery, and other mechanical disturbances. Periodic engine burns for maintaining vehicle attitude and random impulse type disturbances also contribute to the acceleration environment of a Spacecraft. Accelerations from these vibrations (often referred to as g-jitter) are several orders of magnitude larger than the residual accelerations from atmospheric drag and gravity gradient effects. Naturally, the effects of such accelerations have been a concern to prospective experimenters wishing to take advantage of the microgravity environment offered by spacecraft operating in low Earth orbit and the topic has been studied extensively, both numerically and analytically. However, these studies have not produced a general theory that predicts the effects of multi-spectral periodic accelerations on a general class of experiments nor have they produced scaling laws that a prospective experimenter could use to assess how his/her experiment might be affected by this acceleration environment. Furthermore, there are no actual flight experimental data that correlates heat or mass transport with measurements of the periodic acceleration environment. The present investigation approaches this problem with carefully conducted terrestrial experiments and rigorous numerical modeling thereby providing comparative theoretical and experimental data. The modeling, it is hoped will provide a predictive tool that can be used for assessing experiment response to Spacecraft vibrations.

  9. 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

  10. Laser wakefield acceleration experiments at the University of Michigan

    SciTech Connect

    Matsuoka, T.; McGuffey, C.; Horovitz, Y.; Dollar, F.; Bulanov, S. S.; Chvykov, V.; Kalintchenko, G.; Reed, S.; Rousseau, P.; Yanovsky, V.; Maksimchuk, A.; Krushelnick, K.; Huntington, C. M.; Drake, R. P.; Levin, M.; Zigler, A.

    2009-01-22

    Laser wakefield acceleration (LWFA) in a supersonic gas-jet using a self-guided laser pulse was studied by changing the laser power and electron density. The recently upgraded HERCULES laser facility equipped with wavefront correction enables a peak intensity of 8x10{sup 19} W/cm{sup 2} at laser power of 100 TW to be delivered to the gas-jet using f/10 focusing optics. We found that electron beam charge was increased significantly with an increase of the laser power from 30 TW to 80 TW and showed density threshold behavior at a fixed laser power. Betatron motion of electrons was also observed depending on laser power and electron density.

  11. Accelerator Challenges and Opportunities for Future Neutrino Experiments

    SciTech Connect

    Zisman, Michael S

    2010-12-24

    There are three types of future neutrino facilities currently under study, one based on decays of stored beta-unstable ion beams (?Beta Beams?), one based on decays of stored muon beams (?Neutrino Factory?), and one based on the decays of an intense pion beam (?Superbeam?). In this paper we discuss the challenges each design team must face and the R&D being carried out to turn those challenges into technical opportunities. A new program, the Muon Accelerator Program, has begun in the U.S. to carry out the R&D for muon-based facilities, including both the Neutrino Factory and, as its ultimate goal, a Muon Collider. The goals of this program will be briefly described.

  12. Operational experience from a large EPICS-based accelerator facility

    SciTech Connect

    Ciarlette, D.J.; Gerig, R.

    1995-12-31

    The Advanced Photon Source (APS) at Argonne National Laboratory is a third-generation x-ray light source which uses the Experimental Physics and Industrial Control System (EPICS) to operate its linear accelerator, positron accumulator ring, booster synchrotron, and storage ring equipment. EPICS has been used at the APS since the beginning of installation and commissioning. Currently, EPICS controls approximately 100 VME crates containing over 100,000 process variables. With this complexity, the APS has had to review some of the methods originally employed and make changes as necessary. In addition, due to commissioning and operational needs, higher-level operator software needed to be created. EPICS has been flexible enough to allow this.

  13. Age and Gender Differences in Adolescents' Homework Experiences

    ERIC Educational Resources Information Center

    Kackar, Hayal Z.; Shumow, Lee; Schmidt, Jennifer A.; Grzetich, Janel

    2011-01-01

    Extant data collected through the Experience Sampling Method were analyzed to describe adolescents' subjective experiences of homework. Analyses explored age and gender differences in the time adolescents spend doing homework, and the situational variations (location and companions) in adolescents' reported concentration, effort, interest,…

  14. Lived Experiences of College-Age Transsexual Individuals

    ERIC Educational Resources Information Center

    Goodrich, Kristopher M.

    2012-01-01

    This article reviews the lived experiences of 4 college-age transsexual individuals. A qualitative study using grounded theory was conducted to investigate their experiences influencing their later educational persistence. Results suggested that level of discomfort, perceived social supports, level of secrecy, and academic achievement all affected…

  15. Aging after noise exposure: acceleration of cochlear synaptopathy in "recovered" ears.

    PubMed

    Fernandez, Katharine A; Jeffers, Penelope W C; Lall, Kumud; Liberman, M Charles; Kujawa, Sharon G

    2015-05-13

    Cochlear synaptic loss, rather than hair cell death, is the earliest sign of damage in both noise- and age-related hearing impairment (Kujawa and Liberman, 2009; Sergeyenko et al., 2013). Here, we compare cochlear aging after two types of noise exposure: one producing permanent synaptic damage without hair cell loss and another producing neither synaptopathy nor hair cell loss. Adult mice were exposed (8-16 kHz, 100 or 91 dB SPL for 2 h) and then evaluated from 1 h to ∼ 20 months after exposure. Cochlear function was assessed via distortion product otoacoustic emissions and auditory brainstem responses (ABRs). Cochlear whole mounts and plastic sections were studied to quantify hair cells, cochlear neurons, and the synapses connecting them. The synaptopathic noise (100 dB) caused 35-50 dB threshold shifts at 24 h. By 2 weeks, thresholds had recovered, but synaptic counts and ABR amplitudes at high frequencies were reduced by up to ∼ 45%. As exposed animals aged, synaptopathy was exacerbated compared with controls and spread to lower frequencies. Proportional ganglion cell losses followed. Threshold shifts first appeared >1 year after exposure and, by ∼ 20 months, were up to 18 dB greater in the synaptopathic noise group. Outer hair cell losses were exacerbated in the same time frame (∼ 10% at 32 kHz). In contrast, the 91 dB exposure, producing transient threshold shift without acute synaptopathy, showed no acceleration of synaptic loss or cochlear dysfunction as animals aged, at least to ∼ 1 year after exposure. Therefore, interactions between noise and aging may require an acute synaptopathy, but a single synaptopathic exposure can accelerate cochlear aging. PMID:25972177

  16. Aging after Noise Exposure: Acceleration of Cochlear Synaptopathy in “Recovered” Ears

    PubMed Central

    Fernandez, Katharine A.; Jeffers, Penelope W.C.; Lall, Kumud; Liberman, M. Charles

    2015-01-01

    Cochlear synaptic loss, rather than hair cell death, is the earliest sign of damage in both noise- and age-related hearing impairment (Kujawa and Liberman, 2009; Sergeyenko et al., 2013). Here, we compare cochlear aging after two types of noise exposure: one producing permanent synaptic damage without hair cell loss and another producing neither synaptopathy nor hair cell loss. Adult mice were exposed (8–16 kHz, 100 or 91 dB SPL for 2 h) and then evaluated from 1 h to ∼20 months after exposure. Cochlear function was assessed via distortion product otoacoustic emissions and auditory brainstem responses (ABRs). Cochlear whole mounts and plastic sections were studied to quantify hair cells, cochlear neurons, and the synapses connecting them. The synaptopathic noise (100 dB) caused 35–50 dB threshold shifts at 24 h. By 2 weeks, thresholds had recovered, but synaptic counts and ABR amplitudes at high frequencies were reduced by up to ∼45%. As exposed animals aged, synaptopathy was exacerbated compared with controls and spread to lower frequencies. Proportional ganglion cell losses followed. Threshold shifts first appeared >1 year after exposure and, by ∼20 months, were up to 18 dB greater in the synaptopathic noise group. Outer hair cell losses were exacerbated in the same time frame (∼10% at 32 kHz). In contrast, the 91 dB exposure, producing transient threshold shift without acute synaptopathy, showed no acceleration of synaptic loss or cochlear dysfunction as animals aged, at least to ∼1 year after exposure. Therefore, interactions between noise and aging may require an acute synaptopathy, but a single synaptopathic exposure can accelerate cochlear aging. PMID:25972177

  17. A call for virtual experiments: accelerating the scientific process.

    PubMed

    Cooper, Jonathan; Vik, Jon Olav; Waltemath, Dagmar

    2015-01-01

    Experimentation is fundamental to the scientific method, whether for exploration, description or explanation. We argue that promoting the reuse of virtual experiments (the in silico analogues of wet-lab or field experiments) would vastly improve the usefulness and relevance of computational models, encouraging critical scrutiny of models and serving as a common language between modellers and experimentalists. We review the benefits of reusable virtual experiments: in specifying, assaying, and comparing the behavioural repertoires of models; as prerequisites for reproducible research; to guide model reuse and composition; and for quality assurance in the translational application of models. A key step towards achieving this is that models and experimental protocols should be represented separately, but annotated so as to facilitate the linking of models to experiments and data. Lastly, we outline how the rigorous, streamlined confrontation between experimental datasets and candidate models would enable a "continuous integration" of biological knowledge, transforming our approach to systems biology. PMID:25433232

  18. Selection Experiments in the Penna Model for Biological Aging

    NASA Astrophysics Data System (ADS)

    Medeiros, G.; Idiart, M. A.; de Almeida, R. M. C.

    We consider the Penna model for biological aging to investigate correlations between early fertility and late life survival rates in populations at equilibrium. We consider inherited initial reproduction ages together with a reproduction cost translated in a probability that mother and offspring die at birth, depending on the mother age. For convenient sets of parameters, the equilibrated populations present genetic variability in what regards both genetically programmed death age and initial reproduction age. In the asexual Penna model, a negative correlation between early life fertility and late life survival rates naturally emerges in the stationary solutions. In the sexual Penna model, selection experiments are performed where individuals are sorted by initial reproduction age from the equilibrated populations and the separated populations are evolved independently. After a transient, a negative correlation between early fertility and late age survival rates also emerges in the sense that populations that start reproducing earlier present smaller average genetically programmed death age. These effects appear due to the age structure of populations in the steady state solution of the evolution equations. We claim that the same demographic effects may be playing an important role in selection experiments in the laboratory.

  19. 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

  20. Physics study of the TRADE : TRIGA accelerator driven experiment.

    SciTech Connect

    Naberejnev, D.; Imel, G.; Palmiotti, G.; Salvatores, M.

    2004-01-13

    This report deals with the validation of an ADS dynamic behavior through the TRADE program. We first describe the motivations behind the TRADE project. This includes the types of ADS experiments to be performed and their necessity, beam trips issues, representativity of the experiment, and steps to be taken in the validation procedure. Then we perform the characterization of the TRADE core using deterministic methods. The general core description is given. A number of results related to the core criticality and modeling with different geometries are presented. Finally we report the experimental results of the recent critical measurements including the control rod calibration, determination of the critical configurations and fluxes in the core.

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

    PubMed

    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

    2013-03-01

    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

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

    USGS Publications Warehouse

    Stafford, Thomas W., Jr.; Jull, A.J.T.; Zabel, T.H.; Donahue, D.J.; Duhamel, R.C.; Brendel, K.; Haynes, C.V., Jr.; 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.

  3. GPU acceleration experience with RRTMG long wave radiation model

    NASA Astrophysics Data System (ADS)

    Price, Erik; Mielikainen, Jarno; Huang, Bormin; Huang, HungLung A.; Lee, Tsengdar

    2013-10-01

    in many weather forecast and climate models. RRTMG_LW is in operational use in ECMWF weather forecast system, the NCEP global forecast system, the ECHAM5 climate model, Community Earth System Model (CESM) and the weather and forecasting (WRF) model. RRTMG_LW has also been evaluated for use in GFDL climate model. In this paper, we examine the feasibility of using graphics processing units (GPUs) to accelerate the RRTMG_LW as used by the WRF. GPUs can provide a substantial improvement in RRTMG speed by supporting the parallel computation of large numbers of independent radiative calculations. Furthermore, using commodity GPUs for accelerating RRTMG_LW allows getting a much higher computational performance at lower price point than traditional CPUs. Furthermore, power and cooling costs are significantly reduced by using GPUs. A GPU-compatible version of RRTMG was implemented and thorough testing was performed to ensure that the original level of accuracy is retained. Our results show that GPUs can provide significant speedup over conventional CPUs. In particular, Nvidia's GTX 680 GPU card can provide a speedup of 69x for the compared to its single-threaded Fortran counterpart running on Intel Xeon E5-2603 CPU.

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

    PubMed

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

    2016-02-01

    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

  5. 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

  6. 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

  7. Kaonic atoms measurements at the DAFNE accelerator: the SIDDHARTA experiment

    NASA Astrophysics Data System (ADS)

    Rizzo, A.; Bazzi, M.; Beer, G.; Berucci, C.; Bombelli, L.; Bragadireanu, A. M.; Cargnelli, M.; Curceanu (Petrascu, C.; Corradi, G.; dUffizi, A.; Fiorini, C.; Frizzi, T.; Ghio, F.; Guaraldo, C.; Hayano, R. S.; Iliescu, M.; Ishiwatari, T.; Iwasaki, M.; Kienle, P.; Levi Sandri, P.; Longoni, A.; Lucherini, V.; Marton, J.; Okada, S.; Pietreanu, D.; Ponta, T.; Romero Vidal, A.; Sbardella, E.; Scordo, A.; Shi, H.; Sirghi, D. L.; Sirghi, F.; Tatsuno, H.; Tudorache, A.; Tudorache, V.; Vazquez Doce, O.; Widmann, E.; Wunschek, B.; Zmeskal, J.

    2012-03-01

    Kaonic Hydrogen and Helium X-ray measurements play nowadays a fundamental role in testing the reliability of the Chiral Perturbation Theory as a realisation of the Quantum Chromodynamics at low energies. Dictated by both electromagnetic and strong interaction, X-ray transitions at lower energy levels of these complex bound systems offer indeed the unique opportunity to perform a threshold measurements of zero-energy meson-nucleon scattering. Nowadays the SIDDHARTA experiment at DAFNE collider is the only apparatus which can provide such kind of measurements with the high precision needed to disentangle different theoretical calculation scenarios. In this work we present the SIDDHARTA experiment performances and results, with a focus on the main topics of light kaonic atom physics.

  8. 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. PMID:9484071

  9. 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.

  10. High sensitivity to autoxidation in neonatal calf erythrocytes: possible mechanism of accelerated cell aging.

    PubMed

    Imre, S; Csornai, M; Balazs, M

    2001-01-01

    The suspension viscosity, formation of methaemoglobin and production of malondialdehyde (MDA) associated with the non-enzymatic oxidation of polyunsaturated fatty acids during auto-oxidation conditions in vitro have been compared in erythrocytes from young calves (2, 4 and 6 weeks of age) and mature cattle. The autoxidation conditions were designed to simulate the oxidative stress to which neonatal erythrocytes are exposed in vivo. Characterisation of lipid peroxidation was also undertaken by a combination of lipid fluorescent measurements and quantification of the superoxide dismutase (SOD) activities of the erythrocytes. The results demonstrated that high SOD activities in the erythrocytes of the neonatal calf was insufficient to afford protection against the increased autoxidation of haemoglobin and subsequent accumulation of lipid peroxidation products. High levels of methaemoglobin formation and lipid peroxidation were able to provide an explanation for an observed reduction in rheological adaptability (increased suspension viscosity) and an accelerated aging of the neonatal cells under in vivo conditions. PMID:11163624

  11. Space Experiments with Particle Accelerators (SEPAC), status review, 23 September 1980

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The development responsibilities of SEPAC include: accelerator systems, diagnostic systems, power systems, dedicated experiment processor, interface unit, control panel, and all flight software. The operations of SEPAC, including automated experiments under DEP command control and SEPAC manual operations, are outlined. A diagram of the system configuration is presented.

  12. Space radiation accelerator experiments - The role of neutrons and light ions

    NASA Astrophysics Data System (ADS)

    Norbury, John W.; Slaba, Tony C.

    2014-10-01

    The importance of neutrons and light ions is considered when astronauts spend considerable time in thickly shielded regions of a spacecraft. This may be relevant for space missions both in and beyond low Earth orbit (LEO). In addition to heavy ion experiments at accelerators, it is suggested that an increased emphasis on experiments with lighter ions may be useful in reducing biological uncertainties.

  13. 3D Simulations for a Micron-Scale, Dielectric-Based Acceleration Experiment

    SciTech Connect

    Yoder, R. B.; Travish, G.; Xu Jin; Rosenzweig, J. B.

    2009-01-22

    An experimental program to demonstrate a dielectric, slab-symmetric accelerator structure has been underway for the past two years. These resonant devices are driven by a side-coupled 800-nm laser and can be configured to maintain the field profile necessary for synchronous acceleration and focusing of relativistic or nonrelativistic particles. We present 3D simulations of various versions of the structure geometry, including a metal-walled structure relevant to ongoing cold tests on resonant properties, and an all-dielectric structure to be constructed for a proof-of-principle acceleration experiment.

  14. The LILIA experiment: Energy selection and post-acceleration of laser generated protons

    NASA Astrophysics Data System (ADS)

    Turchetti, Giorgio; Sinigardi, Stefano; Londrillo, Pasquale; Rossi, Francesco; Sumini, Marco; Giove, Dario; De Martinis, Carlo

    2012-12-01

    The LILIA experiment is planned at the SPARCLAB facility of the Frascati INFN laboratories. We have simulated the laser acceleration of protons, the transport and energy selection with collimators and a pulsed solenoid and the post-acceleration with a compact high field linac. For the highest achievable intensity corresponding to a = 30 over 108 protons at 30 MeV with a 3% spread are selected, and at least107 protons are post-accelerated up to 60 MeV. If a 10 Hz repetition rated can be achieved the delivered dose would be suitable for the treatment of small superficial tumors.

  15. The LILIA experiment: Energy selection and post-acceleration of laser generated protons

    SciTech Connect

    Turchetti, Giorgio; Sinigardi, Stefano; Londrillo, Pasquale; Rossi, Francesco; Sumini, Marco; Giove, Dario; De Martinis, Carlo

    2012-12-21

    The LILIA experiment is planned at the SPARCLAB facility of the Frascati INFN laboratories. We have simulated the laser acceleration of protons, the transport and energy selection with collimators and a pulsed solenoid and the post-acceleration with a compact high field linac. For the highest achievable intensity corresponding to a= 30 over 10{sup 8} protons at 30 MeV with a 3% spread are selected, and at least10{sup 7} protons are post-accelerated up to 60 MeV. If a 10 Hz repetition rated can be achieved the delivered dose would be suitable for the treatment of small superficial tumors.

  16. Physical conditions for conducting radiobiological experiments in beams of accelerated particles with high linear energy transfer

    NASA Technical Reports Server (NTRS)

    Kudryashov, Y. I.; Marennyy, A. M.; Popov, V. I.; Aykhorn, K.; Ertsgreber, G.

    1974-01-01

    The design and construction of an accelerator to conduct radiobiological experiments is reported that uses aluminum filters to control the accelerated ion beam while preserving its stability, and a vacuum chamber to conduct the ion beam with the help of a collector through a lavsan exit port to the target. Depth distribution of the absorbed dose from a monodirectional ion beam is practically completely represented by the change in the energy spectrum of the biological object.

  17. 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.

  18. 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. PMID:8455156

  19. 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

  20. Lamin A-dependent misregulation of adult stem cells associated with accelerated ageing.

    PubMed

    Scaffidi, Paola; Misteli, Tom

    2008-04-01

    The premature-ageing disease Hutchinson-Gilford Progeria Syndrome (HGPS) is caused by constitutive production of progerin, a mutant form of the nuclear architectural protein lamin A. Progerin is also expressed sporadically in wild-type cells and has been linked to physiological ageing. Cells from HGPS patients exhibit extensive nuclear defects, including abnormal chromatin structure and increased DNA damage. At the organismal level, HGPS affects several tissues, particularly those of mesenchymal origin. How the cellular defects of HGPS cells lead to the organismal defects has been unclear. Here, we provide evidence that progerin interferes with the function of human mesenchymal stem cells (hMSCs). We find that expression of progerin activates major downstream effectors of the Notch signalling pathway. Induction of progerin in hMSCs changes their molecular identity and differentiation potential. Our results support a model in which accelerated ageing in HGPS patients, and possibly also physiological ageing, is the result of adult stem cell dysfunction and progressive deterioration of tissue functions. PMID:18311132

  1. 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

  2. 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

  3. 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.

  4. Sprint Accelerations to First Base Among Major League Baseball Players With Different Years of Career Experience.

    PubMed

    Coleman, A Eugene; Amonette, William E

    2015-07-01

    The purpose of this article was to compare times to first base in Major League Baseball games to determine whether running velocity decreases to the foul line and first base among players with differing years of playing experience. From 1998 to 2012, 1,185 sprint times to first base were analyzed: 469 outfielders, 601 infielders, and 115 catchers. The players were divided into differing experience categories depending on their years of service in Major League Baseball: 1-5, 6-10, 11-15, and 16-20+ years. Velocity at the foul line and first base was compared and interval accelerations were reported. Comparisons were completed by playing position, and within left- and right-handed batters. Left-handed outfielders exhibited reduced velocities at 6-10 (p = 0.04), 11-15 (p = 0.004), and 16-20 years (p < 0.001) compared with 1-5 years; there were no statistical differences in velocity at the foul line. Right-handed outfielders exhibited significantly reduced velocities at first base in 6-10 (p = 0.002) and 11-15 years (p = 0.001); they also had a reduced velocities at the foul line in 6-10 (p = 0.004) and 11-15 years (p = 0.009). Right-handed infielders had reduced velocities at first base in 11-15 years (p < 0.001). No other differences were observed within infielders at first base or the foul line. There were no differences within the compared variables for catchers. Decreases in running velocity to first base with experience are seen in outfielders but are less prominent in infielders and catchers. Although physical capabilities for sprinting may decline with age, it is possible that through repetition more experienced players perfect the skill-related component of running to first base, thus preserving speed. PMID:25353082

  5. A self-injection acceleration test experiment for the FLAME laser

    NASA Astrophysics Data System (ADS)

    Labate, L.; Anelli, F.; Bacci, A.; Batani, D.; Bellaveglia, M.; Benedetti, C.; Benocci, R.; Cacciotti, L.; Cecchetti, C. A.; Ciricosta, O.; Clozza, A.; Cultrera, L.; Di Pirro, G.; Drenska, N.; Faccini, R.; Ferrario, M.; Filippetto, D.; Gallo, S.; Fioravanti, S.; Gamucci, A.; Gatti, G.; Ghigo, A.; Giulietti, A.; Giulietti, D.; Köster, P.; Levato, T.; Lollo, V.; Pace, E.; Pathak, N.; Rossi, A.; Serafini, L.; Turchetti, G.; Vaccarezza, C.; Valente, P.; Vicario, C.; Gizzi, L. A.

    2010-10-01

    A 250-TW laser system (FLAME - Frascati laser for acceleration and multidisciplinary experiments) is now in its commissioning phase in a new laboratory at LNF-INFN in the framework of the PLASMONX (Plasma acceleration and monochromatic X-ray generation) project. The laser will deliver<25 fs duration pulses with an energy up to 6 J, at a 10 Hz repetition rate. An ad hoc target area has also been designed and is currently being set up, allowing the first test experiments of electron laser wakefield acceleration to be carried out over the next few months in a safe, radiation-protected environment. An overview of the main features of the laser system and target area is given, along with a survey of the design and set-up of the self-injection test experiment, which is expected to reach the production of sub-GeV electron bunches.

  6. Shielding Benchmark Experiments Through Concrete and Iron with High-Energy Proton and Heavy Ion Accelerators

    NASA Astrophysics Data System (ADS)

    Nakamura, T.; Sasaki, M.; Nunomiya, T.; Nakao, N.; Kim, E.; Kurosawa, T.; Taniguchi, S.; Iwase, H.; Uwamino, Y.; Shibata, T.; Ito, S.; Fukumura, A.; Perry, D. R.; Wright, P.

    The deep penetration of neutrons through thick shield has become a very serious problem in the shielding design of high-energy, high-intensity accelerator facility. In the design calculation, the Monte Carlo transport calculation through thick shields has large statistical errors and the basic nuclear data and model used in the existing Monte Carlo codes are not well evaluated because of very few experimental data. It is therefore strongly needed to do the deep penetration experiment as shielding benchmark for investigating the calculation accuracy. Under this circumference, we performed the following two shielding experiments through concrete and iron, one with a 800 MeV proton accelerator of the Rutherford Appleton Laboratory (RAL), England and the other with a high energy heavy iron accelerator of the National Institute of Radiological Sciences (NIRS), Japan. Here these two shielding benchmark experiments are outlined.

  7. Evaluation of commercial ADC radiation tolerance for accelerator experiments

    DOE PAGESBeta

    Chen, K.; Chen, H.; Kierstead, J.; Takai, H.; Rescia, S.; Hu, X.; Xu, H.; Mead, J.; Lanni, F.; Minelli, M.

    2015-08-17

    Electronic components used in high energy physics experiments are subjected to a radiation background composed of high energy hadrons, mesons and photons. These particles can induce permanent and transient effects that affect the normal device operation. Ionizing dose and displacement damage can cause chronic damage which disable the device permanently. Transient effects or single event effects are in general recoverable with time intervals that depend on the nature of the failure. The magnitude of these effects is technology dependent with feature size being one of the key parameters. Analog to digital converters are components that are frequently used in detectormore » front end electronics, generally placed as close as possible to the sensing elements to maximize signal fidelity. We report on radiation effects tests conducted on 17 commercially available analog to digital converters and extensive single event effect measurements on specific twelve and fourteen bit ADCs that presented high tolerance to ionizing dose. We discuss mitigation strategies for single event effects (SEE) for their use in the large hadron collider environment.« less

  8. Evaluation of commercial ADC radiation tolerance for accelerator experiments

    SciTech Connect

    Chen, K.; Chen, H.; Kierstead, J.; Takai, H.; Rescia, S.; Hu, X.; Xu, H.; Mead, J.; Lanni, F.; Minelli, M.

    2015-08-17

    Electronic components used in high energy physics experiments are subjected to a radiation background composed of high energy hadrons, mesons and photons. These particles can induce permanent and transient effects that affect the normal device operation. Ionizing dose and displacement damage can cause chronic damage which disable the device permanently. Transient effects or single event effects are in general recoverable with time intervals that depend on the nature of the failure. The magnitude of these effects is technology dependent with feature size being one of the key parameters. Analog to digital converters are components that are frequently used in detector front end electronics, generally placed as close as possible to the sensing elements to maximize signal fidelity. We report on radiation effects tests conducted on 17 commercially available analog to digital converters and extensive single event effect measurements on specific twelve and fourteen bit ADCs that presented high tolerance to ionizing dose. We discuss mitigation strategies for single event effects (SEE) for their use in the large hadron collider environment.

  9. Evaluation of commercial ADC radiation tolerance for accelerator experiments

    NASA Astrophysics Data System (ADS)

    Chen, K.; Chen, H.; Kierstead, J.; Takai, H.; Rescia, S.; Hu, X.; Xu, H.; Mead, J.; Lanni, F.; Minelli, M.

    2015-08-01

    Electronic components used in high energy physics experiments are subjected to a radiation background composed of high energy hadrons, mesons and photons. These particles can induce permanent and transient effects that affect the normal device operation. Ionizing dose and displacement damage can cause chronic damage which disable the device permanently. Transient effects or single event effects are in general recoverable with time intervals that depend on the nature of the failure. The magnitude of these effects is technology dependent with feature size being one of the key parameters. Analog to digital converters are components that are frequently used in detector front end electronics, generally placed as close as possible to the sensing elements to maximize signal fidelity. We report on the development of a technique for testing analog to digital converters for radiation effects, in particular for single event effects. A total of seventeen commercial ADCs were evaluated for ionizing dose tolerance and extensive SEU measurements performed on a twelve and fourteen bit ADCs. Mitigation strategies for single event effects (SEE) are discussed for their use in the large hadron collider environment.

  10. Accelerated aging and human immunodeficiency virus infection: emerging challenges of growing older in the era of successful antiretroviral therapy.

    PubMed

    Bhatia, Ramona; Ryscavage, Patrick; Taiwo, Babafemi

    2012-08-01

    HIV-infected patients are living longer as a result of potent antiretroviral therapy. Immuno-inflammatory phenomena implicated in the normal aging process, including immune senescence, depreciation of the adaptive immune system, and heightened systemic inflammation are also pathophysiologic sequelae of HIV infection, suggesting HIV infection can potentiate the biological mechanisms of aging. Aging HIV-infected patients manifest many comorbidities at earlier ages, and sometimes with more aggressive phenotypes compared to seronegative counterparts. In this review, we describe relevant biologic changes shared by normal aging and HIV infection and explore the growing spectrum of clinical manifestations associated with the accelerated aging phenotype in HIV-infected individuals. PMID:22205585

  11. 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

  12. An investigation into the effectiveness of smartphone experiments on students’ conceptual knowledge about acceleration

    NASA Astrophysics Data System (ADS)

    Mazzella, Alessandra; Testa, Italo

    2016-09-01

    This study is a first attempt to investigate effectiveness of smartphone-based activities on students’ conceptual understanding of acceleration. 143 secondary school students (15–16 years old) were involved in two types of activities: smartphone- and non-smartphone activities. The latter consisted in data logging and ‘cookbook’ activities. For the sake of comparison, all activities featured the same phenomena, i.e., the motion on an inclined plane and pendulum oscillations. A pre-post design was adopted, using open questionnaires as probes. Results show only weak statistical differences between the smartphone and non-smartphone groups. Students who followed smartphone activities were more able to design an experiment to measure acceleration and to correctly describe acceleration in a free fall motion. However, students of both groups had many difficulties in drawing acceleration vector along the trajectory of the studied motion. Results suggest that smartphone-based activities may be effective substitutes of traditional experimental settings and represent a valuable aid for teachers who want to implement laboratory activities at secondary school level. However, to achieve a deeper conceptual understanding of acceleration, some issues need to be addressed: what is the reference system of the built-in smartphone sensor; relationships between smartphone acceleration graphs and experimental setup; vector representation of the measured acceleration.

  13. Modeling laser wakefield accelerator experiments with ultrafast particle-in-cell simulations in boosted frames

    SciTech Connect

    Martins, S. F.; Fonseca, R. A.; Vieira, J.; Silva, L. O.

    2010-05-15

    The development of new laser systems at the 10 Petawatt range will push laser wakefield accelerators to novel regimes, for which theoretical scalings predict the possibility to accelerate electron bunches up to tens of GeVs in meter-scale plasmas. Numerical simulations will play a crucial role in testing, probing, and optimizing the physical parameters and the setup of future experiments. Fully kinetic simulations are computationally very demanding, pushing the limits of today's supercomputers. In this paper, the recent developments in the OSIRIS framework [R. A. Fonseca et al., Lect. Notes Comput. Sci. 2331, 342 (2002)] are described, in particular the boosted frame scheme, which leads to a dramatic change in the computational resources required to model laser wakefield accelerators. Results from one-to-one modeling of the next generation of laser systems are discussed, including the confirmation of electron bunch acceleration to the energy frontier.

  14. 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. PMID:24833306

  15. From randomly accelerated particles to Lévy walks: non-ergodic behavior and aging

    NASA Astrophysics Data System (ADS)

    Radons, Guenter; Albers, Tony; Institute of Physics, Complex Systems; Nonlinear Dynamics Team

    For randomly accelerated particles we detected, and were able to analyze in detail (PRL 113, 184101 (2014)), the phenomenon of weak-ergodicity breaking (WEB), i.e. the inequivalence of ensemble- and time-averaged mean-squared displacements (MSD). These results, including their aging time dependence, are relevant for anomalous chaotic diffusion in Hamiltonian systems, for passive tracer transport in turbulent flows, and many other systems showing momentum diffusion. There are, however, several related models, such as the integrated random excursion model, or, space-time correlated Lévy walks and flights, with similar statistical behavior. We compare the WEB related properties of these models and find surprising differences although, for equivalent parameters, all of them are supposed to lead to the same ensemble-averaged MSD. Our findings are relevant for distinguishing possible models for the anomalous diffusion occurring in experimental situations.

  16. 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.

  17. 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

  18. Laser-based acceleration for nuclear physics experiments at ELI-NP

    NASA Astrophysics Data System (ADS)

    Tesileanu, O.; Asavei, Th.; Dancus, I.; Gales, S.; Negoita, F.; Turcu, I. C. E.; Ursescu, D.; Zamfir, N. V.

    2016-05-01

    As part of the Extreme Light pan-European research infrastructure, Extreme Light Infrastructure - Nuclear Physics (ELI-NP) in Romania will focus on topics in Nuclear Physics, fundamental Physics and applications, based on very intense photon beams. Laser-based acceleration of electrons, protons and heavy ions is a prerequisite for a multitude of laser-driven nuclear physics experiments already proposed by the international research community. A total of six outputs of the dual-amplification chain laser system, two of 100TW, two of 1PW and two of 10PW will be employed in 5 experimental areas, with the possibility to use long and short focal lengths, gas and solid targets, reaching the whole range of laser acceleration processes. We describe the main techniques and expectations regarding the acceleration of electrons, protons and heavy nuclei at ELI-NP, and some physics cases for which these techniques play an important role in the experiments.

  19. Acceleration of heavy and light particles in turbulence: Comparison between experiments and direct numerical simulations

    NASA Astrophysics Data System (ADS)

    Volk, R.; Calzavarini, E.; Verhille, G.; Lohse, D.; Mordant, N.; Pinton, J.-F.; Toschi, F.

    2008-08-01

    We compare experimental data and numerical simulations for the dynamics of inertial particles with finite density in turbulence. In the experiment, bubbles and solid particles are optically tracked in a turbulent flow of water using an Extended Laser Doppler Velocimetry technique. The probability density functions (PDF) of particle accelerations and their auto-correlation in time are computed. Numerical results are obtained from a direct numerical simulation in which a suspension of passive pointwise particles is tracked, with the same finite density and the same response time as in the experiment. We observe a good agreement for both the variance of acceleration and the autocorrelation time scale of the dynamics; small discrepancies on the shape of the acceleration PDF are observed. We discuss the effects induced by the finite size of the particles, not taken into account in the present numerical simulations.

  20. [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

  1. Aging assessment of reactor instrumentation and protection system components. Aging-related operating experiences

    SciTech Connect

    Gehl, A.C.; Hagen, E.W.

    1992-07-01

    A study of the aging-related operating experiences throughout a five-year period (1984--1988) of six generic instrumentation modules (indicators, sensors, controllers, transmitters, annunciators, and recorders) was performed as a part of the Nuclear Plant Aging Research Program. The effects of aging from operational and environmental stressors were characterized from results depicted in Licensee Event Reports (LERs). The data are graphically displayed as frequency of events per plant year for operating plant ages from 1 to 28 years to determine aging-related failure trend patterns. Three main conclusions were drawn from this study: (1) Instrumentation and control (I&C) modules make a modest contribution to safety-significant events: 17% of LERs issued during 1984--1988 dealt with malfunctions of the six I&C modules studied, and 28% of the LERs dealing with these I&C module malfunctions were aging related (other studies show a range 25--50%); (2) Of the six modules studied, indicators, sensors, and controllers account for the bulk (83%) of aging-related failures; and (3) Infant mortality appears to be the dominant aging-related failure mode for most I&C module categories (with the exception of annunciators and recorders, which appear to fail randomly).

  2. Examining Nontraditional Graduate Students' Academic Writing Experiences in an Accelerated Adult Program

    ERIC Educational Resources Information Center

    Crite, Charles E., Jr.

    2013-01-01

    The academic writing competencies of nontraditional graduate students enrolled in accelerated graduate programs have become a growing concern for many higher learning educators in those programs. The purpose of this nonexperimental quantitative study was to examine the writing experiences that impacted nontraditional graduate students enrolled in…

  3. School Counselors' Perceptions and Experience with Acceleration as a Program Option for Gifted and Talented Students

    ERIC Educational Resources Information Center

    Wood, Susannah; Portman, Tarrell Awe Agahe; Cigrand, Dawnette L.; Colangelo, Nicholas

    2010-01-01

    This article presents findings from a national survey of 149 practicing school counselors who are members of the American School Counselor Association. The survey gathered information on school counselors' perceptions of and experiences with acceleration as a program option for gifted students. Results indicate that, although school counselors'…

  4. The Gift of Time: Today's Academic Acceleration Case Study Voices of Experience

    ERIC Educational Resources Information Center

    Scheibel, Susan Riley

    2010-01-01

    The purpose of this qualitative case study was to examine today's academic acceleration from the lived experience and perspectives of two young adults whose education was shortened, thereby allowing them the gift of time. Through personal interviews, parent interviews, and physical artifacts, the researcher gained a complex, holistic understanding…

  5. Recent results from polarization experiments at the LHEP-JINR Accelerator

    SciTech Connect

    Ladygin, V. P.; Azhgirey, L. S.; Gurchin, Yu. V.; Isupov, A. Yu.; Krasnov, V. A.; Khrenov, A. N.; Kiselev, A. S.; Kizka, V. A.; Kurilkin, A. K.; Kurilkin, P. K.; Livanov, A. N.; Ladygina, N. B.; Malakhov, A. I.; Piyadin, S. M.; Reznikov, S. G.; Shikhalev, M. A.; Vasiliev, T. A.; Uesaka, T.; Kawabata, T.; Sakaguchi, S.

    2008-10-13

    The review of recent results from polarization experiments performed at LHEP-JINR Accelerator Complex in a GeV range is given. The current status of the spin program at Nuclotron as well as its further continuation with new high intensity polarized deuterons ion source is discussed.

  6. First experiments on neutron detection on the accelerator-based source for boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Kuznetsov, A. S.; Malyshkin, G. N.; Makarov, A. N.; Sorokin, I. N.; Sulyaev, Yu. S.; Taskaev, S. Yu.

    2009-04-01

    A pilot accelerator-based source of epithermal neutrons, which is intended for wide application in clinics for boron neutron capture therapy, has been constructed at the Budker Institute of Nuclear Physics (Novosibirsk). A stationary proton beam has been obtained and near-threshold neutron generation regime has been realized. Results of the first experiments on neutron generation using the proposed source are described.

  7. Starting Where the Student Is: An Experiment in Accelerated Graduate Social Work Education

    ERIC Educational Resources Information Center

    Eades, Joe C.

    1976-01-01

    A description and interim evaluation of an experimental accelerated master's degree program is presented. The program is designed for students whose undergraduate preparation, work experience, and performance on a qualifying examination suggest that they can benefit from a curriculum that builds directly upon their previous educational and work…

  8. Using a mobile phone acceleration sensor in physics experiments on free and damped harmonic oscillations

    NASA Astrophysics Data System (ADS)

    Carlos Castro-Palacio, Juan; Velázquez-Abad, Luisberis; Giménez, Marcos H.; Monsoriu, Juan A.

    2013-06-01

    We have used a mobile phone acceleration sensor, and the Accelerometer Monitor application for Android, to collect data in physics experiments on free and damped oscillations. Results for the period, frequency, spring constant, and damping constant agree very well with measurements obtained by other methods. These widely available sensors are likely to find increased use in instructional laboratories.

  9. Explaining age differences in women's emotional well-being: The role of subjective experiences of aging.

    PubMed

    Barrett, Anne E; Toothman, Erica L

    2016-01-01

    Our study examines explanations for the "paradox" of older women's better emotional well-being compared with younger women. We consider the role of subjective experiences of aging in a society that devalues older women. Using a sample of women (n = 872) from the National Survey of Midlife Development in the United States (1995-1996 and 2004-2006), we examine the role of five components of the subjective experience of aging in explaining older women's better emotional well-being compared with younger women: age identity, conceptions of the timing of middle age, aging attitudes, aging anxieties, and self-assessed physiological changes. We find that, compared with women 50-54 years old, those 35-39 years old report lower positive affect, and those 25-49 report higher negative affect. These patterns are partially explained by younger women's greater anxiety about declines in health and attractiveness and older women's more youthful identities. Our study underscores the value of considering the implications of our ageist and sexist society for women's emotional well-being across adulthood. PMID:27029460

  10. The Effects of Age, Years of Experience, and Type of Experience in the Teacher Selection Process

    ERIC Educational Resources Information Center

    Vail, David Scott

    2010-01-01

    Paper screening in the pre-selection process of hiring teachers has been the focus in an ongoing series of similar studies starting with Allison in 1981. There have been many independent variables, including, but not limited to, age, gender, ethnic background, years of experience, type of experience, and grade point average, introduced into the…

  11. 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

  12. 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.

  13. 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

  14. Rapid acceleration leads to rapid weakening in earthquake-like laboratory experiments

    NASA Astrophysics Data System (ADS)

    Chang, J. C.; Lockner, D. A.; Reches, Z.

    2012-12-01

    We simulated the slip of a fault-patch during a large earthquake by rapidly loading an experimental, ring-shaped fault with energy stored in a spinning flywheel. The flywheel abruptly delivers a finite amount of energy by spinning the fault-patch that spontaneously dissipates the energy without operator intervention. We conducted 42 experiments on Sierra White granite (SWG) samples, and 24 experiments on Kasota dolomite (KD) samples. Each experiment starts by spinning a 225 kg disk-shaped flywheel to a prescribed angular velocity. We refer to this experiment as an "earthquake-like slip-event" (ELSE). The strength-evolution in ELSE experiments is similar to the strength-evolution proposed for earthquake models and observed in stick-slip experiments. Further, we found that ELSE experiments are similar to earthquakes in at least three ways: (1) slip driven by the release of a finite amount of stored energy; (2) pattern of fault strength evolution; and (3) seismically observed values, such as average slip, peak-velocity and rise-time. By assuming that the measured slip, D, in ELSE experiments is equivalent to the average slip during an earthquake, we found that ELSE experiments (D = 0.003-4.6 m) correspond to earthquakes in moment-magnitude range of Mw = 4-8. In ELSE experiments, the critical-slip-distance, dc, has mean values of 2.7 cm and 1.2 cm for SWG and KD, that are much shorter than the 1-10 m in steady-state classical experiments in rotary shear systems. We attribute these dc values, to ELSE loading in which the fault-patch is abruptly loaded by impact with a spinning flywheel. Under this loading, the friction-velocity relations are strikingly different from those under steady-state loading on the same rock samples with the same shear system (Reches and Lockner, Nature, 2010). We further note that the slip acceleration in ELSE evolves systematically with fault strength and wear-rate, and that the dynamic weakening is restricted to the period of intense

  15. Experiments in sensing transient rotational acceleration cues on a flight simulator

    NASA Technical Reports Server (NTRS)

    Parrish, R. V.

    1979-01-01

    Results are presented for two transient motion sensing experiments which were motivated by the identification of an anomalous roll cue (a 'jerk' attributed to an acceleration spike) in a prior investigation of realistic fighter motion simulation. The experimental results suggest the consideration of several issues for motion washout and challenge current sensory system modeling efforts. Although no sensory modeling effort is made it is argued that such models must incorporate the ability to handle transient inputs of short duration (some of which are less than the accepted latency times for sensing), and must represent separate channels for rotational acceleration and velocity sensing.

  16. Vibration isolation technology: Sensitivity of selected classes of experiments to residual accelerations

    NASA Technical Reports Server (NTRS)

    Alexander, J. Iwan D.

    1990-01-01

    The solution was sought of a 2-D axisymmetric moving boundary problem for the sensitivity of isothermal and nonisothermal liquid columns and the sensitivity of thermo-capillary flows to buoyancy driven convection caused by residual accelerations. The sensitivity of a variety of space experiments to residual accelerations are examined. In all the cases discussed, the sensitivity is related to the dynamic response of a fluid. In some cases the sensitivity can be defined by the magnitude of the response of the velocity field. This response may involve motion of the fluid associated with internal density gradients, or the motion of a free liquid surface. For fluids with internal density gradients, the type of acceleration to which the experiment is sensitive will depend on whether buoyancy driven convection must be small in comparison to other types of fluid motion (such as thermocapillary flow), or fluid motion must be suppressed or eliminated (such as in diffusion studies, or directional solidification experiments). The effect of the velocity on the composition and temperature field must be considered, particularly in the vicinity of the melt crystal interface. As far as the response to transient disturbances is concerned the sensitivity is determined by both the magnitude and frequency the acceleration and the characteristic momentum and solute diffusion times.

  17. The High-Luminosity upgrade of the LHC: Physics and Technology Challenges for the Accelerator and the Experiments

    NASA Astrophysics Data System (ADS)

    Schmidt, Burkhard

    2016-04-01

    In the second phase of the LHC physics program, the accelerator will provide an additional integrated luminosity of about 2500/fb over 10 years of operation to the general purpose detectors ATLAS and CMS. This will substantially enlarge the mass reach in the search for new particles and will also greatly extend the potential to study the properties of the Higgs boson discovered at the LHC in 2012. In order to meet the experimental challenges of unprecedented pp luminosity, the experiments will need to address the aging of the present detectors and to improve the ability to isolate and precisely measure the products of the most interesting collisions. The lectures gave an overview of the physics motivation and described the conceptual designs and the expected performance of the upgrades of the four major experiments, ALICE, ATLAS, CMS and LHCb, along with the plans to develop the appropriate experimental techniques and a brief overview of the accelerator upgrade. Only some key points of the upgrade program of the four major experiments are discussed in this report; more information can be found in the references given at the end.

  18. A small scale accelerator driven subcritical assembly development and demonstration experiment at LAMPF

    SciTech Connect

    Wender, S.A.; Venneri, F.; Bowman, C.D.; Arthur, E.D.; Heighway, E.A.; Beard, C.A.; Bracht, R.R.; Buksa, J.J.; Chavez, W.; DeVolder, B.G.

    1994-10-01

    A small scale experiment is described that will demonstrate many of the aspects of accelerator-driven transmutation technology. This experiment uses the high-power proton beam from the Los Alamos Meson Physics Facility accelerator and will be located in the Area-A experimental hall. Beam currents of up to 1 mA will be used to produce neutrons with a molten lead target. The target is surrounded by a molten salt and graphite moderator blanket. Fissionable material can be added to the molten salt to demonstrate plutonium burning or transmutation of commercial spent fuel or energy production from thorium. The experiment will be operated at power levels up to 5 MW{sub t}.

  19. A linear accelerator in the space: The beam experiment aboard rocket

    SciTech Connect

    O'Shea, P.G.; Butler, T.A.; Lynch, M.T.; McKenna, K.F.; Pongratz, M.B.

    1990-01-01

    On July 13, 1989 the BEAM experiment Aboard Rocket (BEAR) linear accelerator was successfully launched and operated in space. The flight demonstrated that a neutral hydrogen beam could be successfully propagated in an exoatmospheric environment. The accelerator, which was the result of an extensive collaboration between Los Alamos National Laboratory and industrial partners, was designed to produce a 10 mA (equivalent), 1 MeV neutral hydrogen beam in 50 {mu}s pulses at 5 Hz. The major components were a 30 keV H{sup {minus}} injector a 1 MeV radio frequency quadrupole, two 425 Mhz RF amplifiers, a gas cell neutralizer, beam optics, vacuum system and controls. The design was strongly constrained by the need for a lightweight rugged system that would survive the rigors of launch and operate autonomously. Following the flight the accelerator was recovered and operated again on the laboratory. 6 figs., 2 tabs.

  20. STS-40 orbital acceleration research experiment flight results during a typical sleep period

    NASA Technical Reports Server (NTRS)

    Blanchard, Robert C.; Nicholson, John Y.; Ritter, James R.

    1992-01-01

    The Orbital Acceleration Research Experiment (OARE), an electrostatic accelerometer package with complete on-orbit calibration capabilities was flown aboard Shuttle on STS-40. The instrument is designed to measure and record the Shuttle aerodynamic acceleration environment from the free molecule flow regime through the rarefied flow transition into the hypersonic continuum regime. Because of its sensitivity, the OARE instrument detects aerodynamic behavior of the Shuttle while in low-earth orbit. A 2-h orbital time period on day seven of the mission, when the crew was asleep and other spacecraft activities were at a minimum, was examined. Examination of the model with the flight data shows the instrument to be sensitive to all major expected low-frequency acceleration phenomena; however, some erratic instrument bias behavior persists in two axes. In these axes, the OARE data can be made to match a comprehensive atmospheric-aerodynamic model by making bias adjustments and slight liner corrections for drift.

  1. The ANL experiment for a wake field accelerator using an rf structure

    SciTech Connect

    Ruggiero, A.G.; Schoessow, P.; Simpson, J.

    1986-08-27

    Experiments are planned at ANL to study a new accelerating concept that has been developed during the last few years named the WAKEATRON. This requires a very special, simple configuration of the beams and of the rf structure involved. The basic concepts are explained. Like most proposed experimental work, this too was initiated by a considerable amount of computational work, both analytical and numerical, on which we would like to report. We will then describe details of the planned experiments we will carry out at ANL to check some of our predictions for this concept. These experiments concentrate on beam and cavity geometry applicable to the Wakeatron.

  2. The LACARA Vacuum Laser Accelerator Experiment: Beam Positioning and Alignment in a Strong Magnetic Field

    SciTech Connect

    Shchelkunov, Sergey V.; Marshall, T. C.; Hirshfield, J. L.; Wang, Changbiao; LaPointe, M. A.

    2006-11-27

    LACARA (laser cyclotron auto-resonance accelerator) is a vacuum laser accelerator of electrons that is under construction at the Accelerator Test Facility (ATF), Brookhaven National Laboratory. It is expected that the experiment will be assembled by September 2006; this paper presents progress towards this goal. According to numerical studies, as an electron bunch moves along the LACARA solenoidal magnetic field ({approx}5.2 T, length {approx}1 m), it will be accelerated from 50 to {approx}75 MeV by interacting with a 0.8 TW Gaussian-mode circularly polarized optical pulse provided by the ATF CO2 10.6{mu}m laser system. The LACARA laser transport optics must handle 10 J and be capable of forming a Gaussian beam inside the solenoid with a 1.4 mm waist and a Rayleigh range of 60 cm. The electron optics must transport a bunch having input emittance of 0.015 mm-mrad and 100 {mu}m waist through the magnet. Precision alignment between the electron beam and the solenoid magnetic axis is required, and a method to achieve this is described in detail. Emittance- filtering may be necessary to yield an accelerated bunch having a narrow ({approx}1%) energy-spread.

  3. Helicon Plasma Injector and Ion Cyclotron Acceleration Development in the VASIMR Experiment

    NASA Technical Reports Server (NTRS)

    Squire, Jared P.; Chang, Franklin R.; Jacobson, Verlin T.; McCaskill, Greg E.; Bengtson, Roger D.; Goulding, Richard H.

    2000-01-01

    In the Variable Specific Impulse Magnetoplasma Rocket (VASIMR) radio frequency (rf) waves both produce the plasma and then accelerate the ions. The plasma production is done by action of helicon waves. These waves are circular polarized waves in the direction of the electron gyromotion. The ion acceleration is performed by ion cyclotron resonant frequency (ICRF) acceleration. The Advanced Space Propulsion Laboratory (ASPL) is actively developing efficient helicon plasma production and ICRF acceleration. The VASIMR experimental device at the ASPL is called VX-10. It is configured to demonstrate the plasma production and acceleration at the 10kW level to support a space flight demonstration design. The VX-10 consists of three electromagnets integrated into a vacuum chamber that produce magnetic fields up to 0.5 Tesla. Magnetic field shaping is achieved by independent magnet current control and placement of the magnets. We have generated both helium and hydrogen high density (>10(exp 18) cu m) discharges with the helicon source. ICRF experiments are underway. This paper describes the VX-10 device, presents recent results and discusses future plans.

  4. 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. PMID:24726964

  5. Motivation for proposed experimentation in the realm of accelerated E. M. systems: A preliminary design for an experiment

    NASA Technical Reports Server (NTRS)

    Post, E. J.

    1970-01-01

    An experiment, designed to determine the difference between fields-magnetic and electric-surrounding a uniformly moving charge as contrasted with the fields surrounding an accelerated charge, is presented. A thought experiment is presented to illustrate the process.

  6. 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).

  7. DNA damage drives accelerated bone aging via an NF-κB-dependent mechanism

    PubMed Central

    Chen, Qian; Liu, Kai; Robinson, Andria R.; Clauson, Cheryl L.; Blair, Harry C.; Robbins, Paul D.; Niedernhofer, Laura J.; Ouyang, Hongjiao

    2013-01-01

    Advanced age is one of the most important risk factors for osteoporosis. Accumulation of oxidative DNA damage has been proposed to contribute to age-related deregulation of osteoblastic and osteoclastic cells. ERCC1 (Excision Repair Cross Complementary group 1)-XPF (Xeroderma Pigmentosum Group F) is an evolutionarily conserved structure-specific endonuclease that is required for multiple DNA repair pathways. Inherited mutations affecting expression of ERCC1-XPF cause a severe progeroid syndrome in humans, including early onset of osteopenia and osteoporosis, or anomalies in skeletal development. Herein, we used progeroid ERCC1-XPF deficient mice, including Ercc1-null (Ercc1−/−) and hypomorphic (Ercc1−/Δ) mice, to investigate the mechanism by which DNA damage leads to accelerated bone aging. Compared to their wild-type littermates, both Ercc1−/− and Ercc1−/Δ mice display severe, progressive osteoporosis caused by reduced bone formation and enhanced osteoclastogenesis. ERCC1 deficiency leads to atrophy of osteoblastic progenitors in the bone marrow stromal cell (BMSC) population. There is increased cellular senescence of BMSCs and osteoblastic cells, as characterized by reduced proliferation, accumulation of DNA damage and a senescence-associated secretory phenotype (SASP). This leads to enhanced secretion of inflammatory cytokines known to drive osteoclastogenesis, such as IL-6, TNFα, and RANKL and thereby induces an inflammatory bone microenvironment favoring osteoclastogenesis. Furthermore, we found that the transcription factor NF-κB is activated in osteoblastic and osteoclastic cells of the Ercc1 mutant mice. Importantly, we demonstrated that haploinsufficiency of the p65 NF-κB subunit partially rescued the osteoporosis phenotype of Ercc1−/Δ mice. Finally, pharmacological inhibition of the NF-κB signaling via an IKK inhibitor reversed cellular senescence and SASP in Ercc1−/Δ BMSCs. These results demonstrate that DNA damage drives

  8. Testing a model of aging in animal experiments.

    PubMed

    Tyurin YuN; Yakovlev AYu; Shi, J; Bass, L

    1995-03-01

    A stochastic model of aging is developed in terms of accumulation and expression of intracellular lesions caused by environment or intrinsic genetic program. In contrast to the commonly used Gompertz-Makeham approach to the parametric analysis of mortality data, the model yields a hazard function that is bounded from above. For testing the model in experiments aimed at studying animal longevity, a Kolmogorov-type statistical test is presented with regard to the hypothesis involving unknown parameters. Examples concerning longevity of intact animals of two different species, as well as the effect of a prolonged irradiation at a low dose rate, are given to illustrate the model application and goodness-of-fit testing. The results of the analysis of published data show that the rate of lesion formation is not sustained at a constant level throughout life, though in some cases its variations with age can be considered negligible. PMID:7766791

  9. Effect of dietary, social, and lifestyle determinants of accelerated aging and its common clinical presentation: A survey study.

    PubMed

    Samarakoon, S M S; Chandola, H M; Ravishankar, B

    2011-07-01

    Aging is unavoidable and natural phenomenon of life. Modern gerontologists are realizing the fact that aging is a disease, which Ayurveda had accepted as natural disease since long. Rate of aging is determined by one's biological, social, lifestyle, and psychological conditions and adversity of which leads to accelerated form of aging (Akalaja jara or premature aging). The aim of this study is to identify potential factors that may accelerate aging in the context of dietry factors, lifestyle and mental makeup. The 120 diagnosed subjects of premature-ageing of 30-60 years were randomly selected in the survey study. Premature ageing was common among females (75.83%), in 30-40 age group (70%), 86.67% were married, had secondary level of education (36.66%), house-views (61.67%), belongs top middle class (58.33%) and engaged in occupations that dominating physical labour (88.33%). The maximum patients are constipated (60%), had mandagni (80%), vata-kapha prakriti (48.33%), rajasika prakriti (58.33%), madhyama vyayama shakti (73.33%), and madhyama jarana shakti (85.83%). Collectively, 43.33% patients were above normal BMI. The more patients had anushna (38.33%) and vishamasana dietary pattern (25.83%), consumed Lavana (88.33%) and Amla rasa (78.33%) in excess on regular basis. Some patients had addicted to tobacco (11.67%) and beetle chewing (5.83%). The maximum patients had no any exercise (79.17%) and specific hobby (79.17%) in their leisure times. Analyzing Hamilton Anxiety and Depression Rating Scales revealed that 39.80%, 37.86%, 33.98%, 24.27% and 18.44% patients had insomnia, depression, tension, GIT symptoms and anxious mood respectively. These data suggest that certain social, dietary and lifestyle factors contribute towards accelerated ageing among young individuals. PMID:22529643

  10. Mechanisms of maladaptive repair after AKI leading to accelerated kidney ageing and CKD

    PubMed Central

    Ferenbach, David A.; Bonventre, Joseph V.

    2015-01-01

    Acute kidney injury is an increasingly common complication of hospital admission and is associated with high levels of morbidity and mortality. A hypotensive, septic, or toxic insult can initiate a cascade of events, resulting in impaired microcirculation, activation of inflammatory pathways and tubular cell injury or death. These processes ultimately result in acutely impaired kidney function and initiation of a repair response. This Review explores the various mechanisms responsible for the initiation and propagation of acute kidney injury, the prototypic mechanisms by which a substantially damaged kidney can regenerate its normal architecture, and how the adaptive processes of repair can become maladaptive. These mechanisms, which include G2/M cell-cycle arrest, cell senescence, profibrogenic cytokine production, and activation of pericytes and interstitial myofibroblasts, contribute to the development of progressive fibrotic kidney disease. The end result is a state that mimics accelerated kidney ageing. These mechanisms present important opportunities for the design of targeted therapeutic strategies to promote adaptive renal recovery and minimize progressive fibrosis and chronic kidney disease after acute insults. PMID:25643664

  11. 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.

  12. 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.

  13. Sox4 Links Tumor Suppression to Accelerated Aging in Mice by Modulating Stem Cell Activation

    PubMed Central

    Foronda, Miguel; Martínez, Paula; Schoeftner, Stefan; Gómez-López, Gonzalo; Schneider, Ralph; Flores, Juana M.; Pisano, David G.; Blasco, Maria A.

    2016-01-01

    Summary Sox4 expression is restricted in mammals to embryonic structures and some adult tissues, such as lymphoid organs, pancreas, intestine, and skin. During embryogenesis, Sox4 regulates mesenchymal and neural progenitor survival, as well as lymphocyte and myeloid differentiation, and contributes to pancreas, bone, and heart development. Aberrant Sox4 expression is linked to malignant transformation and metastasis in several types of cancer. To understand the role of Sox4 in the adult organism, we first generated mice with reduced whole-body Sox4 expression. These mice display accelerated aging and reduced cancer incidence. To specifically address a role for Sox4 in adult stem cells, we conditionally deleted Sox4 (Sox4cKO) in stratified epithelia. Sox4cKO mice show increased skin stem cell quiescence and resistance to chemical carcinogenesis concomitantly with downregulation of cell cycle, DNA repair, and activated hair follicle stem cell pathways. Altogether, these findings highlight the importance of Sox4 in regulating adult tissue homeostasis and cancer. PMID:25043184

  14. 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

  15. Rapid acceleration leads to rapid weakening in earthquake-like laboratory experiments

    USGS Publications Warehouse

    Chang, Jefferson C.; Lockner, David A.; Reches, Z.

    2012-01-01

    After nucleation, a large earthquake propagates as an expanding rupture front along a fault. This front activates countless fault patches that slip by consuming energy stored in Earth’s crust. We simulated the slip of a fault patch by rapidly loading an experimental fault with energy stored in a spinning flywheel. The spontaneous evolution of strength, acceleration, and velocity indicates that our experiments are proxies of fault-patch behavior during earthquakes of moment magnitude (Mw) = 4 to 8. We show that seismically determined earthquake parameters (e.g., displacement, velocity, magnitude, or fracture energy) can be used to estimate the intensity of the energy release during an earthquake. Our experiments further indicate that high acceleration imposed by the earthquake’s rupture front quickens dynamic weakening by intense wear of the fault zone.

  16. Recent Developments on ALICE (Accelerators and Lasers In Combined Experiments) at Daresbury Laboratory

    SciTech Connect

    Saveliev, Y M; Buckley, R K; Buckley, S R; Clarke, J A; Corlett, P A; Dunning, D J; Goulden, A R; Hill, S F; Jackson, F; Jamison, S P; Jones, J K; Jones, L B; Leonard, S; McIntosh, P A; McKenzie, J W; Middleman, K J; Militsyn, B L; Moss, A J; Muratori, B D; Orrett, J F; Pattalwar, S M; Phillips, P J; Scott, D J; Seddon, E A; Shepherd, B.J.A.; Smith, S L; Thompson, N; Wheelhouse, A E; Williams, P H; Harrison, P; Holder, D J; Holder, G M; Schofield, A L; Weightman, P; Williams, R L; Laundry, D; Powers, T; Priebe, G; Surman, M

    2010-05-01

    Progress made in ALICE (Accelerators and Lasers In Combined Experiments) commissioning and a summary of the latest experimental results are presented in this paper. After an extensive work on beam loading effects in SC RF linac (booster) and linac cavities conditioning, ALICE can now operate in full energy recovery mode at the bunch charge of 40pC, the beam energy of 30MeV and train lengths of up to 100us. This improved operation of the machine resulted in generation of coherently enhanced broadband THz radiation with the energy of several tens of uJ per pulse and in successful demonstration of the Compton Backscattering x-ray source experiment. The next steps in the ALICE scientific programme are commissioning of the IR FEL and start of the research on the first non-scaling FFAG accelerator EMMA. Results from both projects will be also reported.

  17. Rapid Acceleration Leads to Rapid Weakening in Earthquake-Like Laboratory Experiments

    NASA Astrophysics Data System (ADS)

    Chang, J. C.; Lockner, D. A.; Reches, Z.

    2012-10-01

    After nucleation, a large earthquake propagates as an expanding rupture front along a fault. This front activates countless fault patches that slip by consuming energy stored in Earth’s crust. We simulated the slip of a fault patch by rapidly loading an experimental fault with energy stored in a spinning flywheel. The spontaneous evolution of strength, acceleration, and velocity indicates that our experiments are proxies of fault-patch behavior during earthquakes of moment magnitude (Mw) = 4 to 8. We show that seismically determined earthquake parameters (e.g., displacement, velocity, magnitude, or fracture energy) can be used to estimate the intensity of the energy release during an earthquake. Our experiments further indicate that high acceleration imposed by the earthquake’s rupture front quickens dynamic weakening by intense wear of the fault zone.

  18. Preliminary Results from the UCLA/SLAC Ultra-High Gradient CerenkovWakefield Accelerator Experiment

    SciTech Connect

    Thompson, M.C.; Badakov, H.; Rosenzweig, J.B.; Travish, G.; Hogan, M.; Ischebeck, R.; Kirby, N.; Siemann, R.; Walz, D.; Muggli, P.; Scott, A.; Yoder, R.; /Manhattan Coll., Riverdale

    2008-02-06

    The first phase of an experiment to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range has been completed. This experiment takes advantage of the unique SLAC FFTB electron beam and its demonstrated ultra-short pulse lengths and high currents (e.g., {sigma}{sub z} = 20 {micro}m at Q = 3 nC). The FFTB electron beam has been successfully focused down and sent through varying lengths of fused silica capillary tubing with two different sizes: ID = 200 {micro}m/OD = 325 {micro}m and ID = 100 {micro}m/OD = 325 {micro}m. The pulse length of the electron beam was varied in the range 20 {micro}m < {sigma}{sub z} < 100 {micro}m which produced a range of electric fields between 2 and 20 GV/m at the inner surface of the dielectric tubes. We observed a sharp increase in optical emissions from the capillaries in the middle part of this surface field range which we believe indicates the transition between sustainable field levels and breakdown. If this initial interpretation is correct, the surfaced fields that were sustained equate to on axis accelerating field of several GV/m. In future experiments we plan to collect and measure coherent Cerenkov radiation emitted from the capillary tube to gain more information about the strength of the accelerating fields.

  19. Applied-B ion diode experiments on the Particle Beam Fusion Accelerator-I

    NASA Astrophysics Data System (ADS)

    Dreike, P. L.; Burns, E. J. T.; Slutz, S. A.; Crow, J. T.; Johnson, D. J.; Johnson, P. R.; Leeper, R. J.; Miller, P. A.; Mix, L. P.; Seidel, D. B.; Wenger, D. F.

    1986-08-01

    A series of experiments was performed with an Applied-B ion diode on the Particle Beam Fusion Accelerator-I, with peak voltage, current, and power of approximately 1.8 MV, 6 MA, and 6 TW, respectively. The purpose of these experiments was to explore issues of scaling of Applied-B diode operation from the sub-TW level on single module accelerators to the multi-TW level on a low impedance, self-magnetically insulated, multimodule accelerator. This is an essential step in the development of the 100-TW level light ion beam driver required for inertial confinement fusion. The accelerator and the diode are viewed as a whole because the power pulse delivered by the 36 imperfectly synchronized magnetically insulated transmission lines to the single diode affects module addition, diode operation, and ion beam focusability. We studied electrical coupling between the accelerator and the diode, power flow symmetry, the ionic composition of the beam, and the focusability of the proton component of the beam. Scaling of the diode impedance behavior and beam quality with electrical drive power is obtained from comparison with lower-power experiments. The diode impedance lifetime was about 10 ns, several times shorter than for lower-power experiments. Azimuthal and top-to-bottom variations of the diode and ion currents were found to be approximately ±10%, compared with an estimated requirement of 5%-7% uniformity to avoid focal blurring by self-magnetic field effects. The ion production efficiency was 80%-90%. However, only 50%±10% of the ion current was carried by protons; the balance was carried by multiply charged carbon and oxygen ions. Activation measurements showed a proton beam energy of approximately 50 kJ. A gas cell filled with 5 Torr of argon was used for beam transport. The macroscopic divergence was 15±10 mrad and the microscopic divergence was 20±15 mrad, values that are similar to those from lower-power experiments. A model of beam focusing is formulated that

  20. 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

  1. Accelerating the connection between experiments and models: The FACE-MDS experience

    NASA Astrophysics Data System (ADS)

    Norby, R. J.; Medlyn, B. E.; De Kauwe, M. G.; Zaehle, S.; Walker, A. P.

    2014-12-01

    The mandate is clear for improving communication between models and experiments to better evaluate terrestrial responses to atmospheric and climatic change. Unfortunately, progress in linking experimental and modeling approaches has been slow and sometimes frustrating. Recent successes in linking results from the Duke and Oak Ridge free-air CO2 enrichment (FACE) experiments with ecosystem and land surface models - the FACE Model-Data Synthesis (FACE-MDS) project - came only after a period of slow progress, but the experience points the way to future model-experiment interactions. As the FACE experiments were approaching their termination, the FACE research community made an explicit attempt to work together with the modeling community to synthesize and deliver experimental data to benchmark models and to use models to supply appropriate context for the experimental results. Initial problems that impeded progress were: measurement protocols were not consistent across different experiments; data were not well organized for model input; and parameterizing and spinning up models that were not designed for simulating a specific site was difficult. Once these problems were worked out, the FACE-MDS project has been very successful in using data from the Duke and ORNL FACE experiment to test critical assumptions in the models. The project showed, for example, that the stomatal conductance model most widely used in models was supported by experimental data, but models did not capture important responses such as increased leaf mass per unit area in elevated CO2, and did not appropriately represent foliar nitrogen allocation. We now have an opportunity to learn from this experience. New FACE experiments that have recently been initiated, or are about to be initiated, include a eucalyptus forest in Australia; the AmazonFACE experiment in a primary, tropical forest in Brazil; and a mature oak woodland in England. Cross-site science questions are being developed that will have a

  2. Aging reduces experience-induced sensorimotor plasticity. A magnetoencephalographic study.

    PubMed

    Mary, Alison; Bourguignon, Mathieu; Wens, Vincent; Op de Beeck, Marc; Leproult, Rachel; De Tiège, Xavier; Peigneux, Philippe

    2015-01-01

    Modulation of the mu-alpha and mu-beta spontaneous rhythms reflects plastic neural changes within the primary sensorimotor cortex (SM1). Using magnetoencephalography (MEG), we investigated how aging modifies experience-induced plasticity after learning a motor sequence, looking at post- vs. pre-learning changes in the modulation of mu rhythms during the execution of simple hand movements. Fifteen young (18-30 years) and fourteen older (65-75 years) right-handed healthy participants performed auditory-cued key presses using all four left fingers simultaneously (Simple Movement task - SMT) during two separate sessions. Following both SMT sessions, they repeatedly practiced a 5-elements sequential finger-tapping task (FTT). Mu power calculated during SMT was averaged across 18 gradiometers covering the right sensorimotor region and compared before vs. after sequence learning in the alpha (9/10/11Hz) and the beta (18/20/22Hz) bands separately. Source power maps in the mu-alpha and mu-beta bands were localized using Dynamic Statistical Parametric Mapping (dSPM). The FTT sequence was performed faster at retest than at the end of the learning session, indicating an offline boost in performance. Analyses conducted on SMT sessions revealed enhanced rebound after learning in the right SM1, 3000-3500ms after the initiation of movement, in young as compared to older participants. Source reconstruction indicated that mu-beta is located in the precentral gyrus (motor processes) and mu-alpha is located in the postcentral gyrus (somatosensory processes) in both groups. The enhanced post-movement rebound in young subjects potentially reflects post-training plastic changes in SM1. Age-related decreases in post-training modulatory effects suggest reduced experience-dependent plasticity in the aging brain. PMID:25315784

  3. 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.

  4. Informed Practice: Students' Clinical Experiences in the Undergraduate Phase of an Accelerated Physician Assistant Program.

    PubMed

    Dereczyk, Amy; DeWitt, Rachel

    2016-06-01

    This qualitative study explored the clinical experiences of students in an accelerated physician assistant (PA) program. The participants were either certified nursing assistants (CNAs) or emergency medical technicians-basic (EMTs-B). The study was designed to elicit (1) how the participants perceived their older patients and (2) how the participants' experiences might affect their own future communications, bedside manner, and clinical preparedness as PAs. This study used a focus group to explore students' clinical experiences before the graduate phase of their accelerated PA program. Five female and 2 male PA students (N = 7) participated in the study. All participants were 23 years old and worked as either a CNA or an EMT-B. Results fell into 2 basic themes: informing practice and forming relationships. Regarding the first theme, participants felt that their experience as entry-level health care providers allowed them to improve their communication skills and bedside manner and to provide greater comfort to patients. Regarding the second theme, participants gained appreciation for older people and began to recognize the knowledge deficits and learning needs of their patients. The results suggested that a student's clinical experience as a CNA or an EMT-B before entering a PA program has a positive effect on the student's personal and professional development. The participants acquired greater appreciation and respect for older patients and members of the health care team. PMID:27123599

  5. Lattice design of the integrable optics test accelerator and optical stochastic cooling experiment at Fermilab

    SciTech Connect

    Kafka, Gene

    2015-05-01

    The Integrable Optics Test Accelerator (IOTA) storage ring at Fermilab will serve as the backbone for a broad spectrum of Advanced Accelerator R&D (AARD) experiments, and as such, must be designed with signi cant exibility in mind, but without compromising cost e ciency. The nonlinear experiments at IOTA will include: achievement of a large nonlinear tune shift/spread without degradation of dynamic aperture; suppression of strong lattice resonances; study of stability of nonlinear systems to perturbations; and studies of di erent variants of nonlinear magnet design. The ring optics control has challenging requirements that reach or exceed the present state of the art. The development of a complete self-consistent design of the IOTA ring optics, meeting the demands of all planned AARD experiments, is presented. Of particular interest are the precise control for nonlinear integrable optics experiments and the transverse-to-longitudinal coupling and phase stability for the Optical Stochastic Cooling Experiment (OSC). Since the beam time-of- ight must be tightly controlled in the OSC section, studies of second order corrections in this section are presented.

  6. High Frequency, High Gradient Dielectric Wakefield Acceleration Experiments at SLAC and BNL

    NASA Astrophysics Data System (ADS)

    Rosenzweig, J. B.; Andonian, G.; Muggli, P.; Niknejadi, P.; Travish, G.; Williams, O.; Xuan, K.; Yakimenko, V.

    2010-11-01

    Given the recent success of >GV/m dielectric wakefield accelerator (DWA) breakdown experiments at SLAC, and follow-on coherent Cerenkov radiation (CCR) production at the UCLA Neptune, a UCLA-USC-SLAC collaboration is now implementing a new set of experiments that explore various DWA scenarios. These experiments are motivated by the opportunities presented by the approval of the FACET facility at SLAC, as well as unique pulse-train wakefield drivers at BNL. The SLAC experiments permit further exploration of the multi-GeV/m envelope in DWAs, and will entail investigations of novel materials (e.g. CVD diamond) and geometries (Bragg cylindrical structures, slab-symmetric DWAs), and have an over-riding goal of demonstrating >GeV acceleration in ˜33 cm DWA tubes. In the nearer term before FACET's commissioning, we are performing measurements at the BNL ATF, in which we drive ˜50-200 MV/m fields with single pulses or pulse trains, and observe resonantly driven CCR as well as deflection modes. These experiments are of high relevance to enhancing linear collider DWA designs, as they will demonstrate potential for high efficiency operation with pulse trains, and explore transverse modes for the first time.

  7. Lattice design of the integrable optics test accelerator and optical stochastic cooling experiment at Fermilab

    NASA Astrophysics Data System (ADS)

    Kafka, Gene

    The Integrable Optics Test Accelerator (IOTA) storage ring at Fermilab will serve as the backbone for a broad spectrum of Advanced Accelerator R&D (AARD) experiments, and as such, must be designed with significant flexibility in mind, but without compromising cost efficiency. The nonlinear experiments at IOTA will include: achievement of a large nonlinear tune shift/spread without degradation of dynamic aperture; suppression of strong lattice resonances; study of stability of nonlinear systems to perturbations; and studies of different variants of nonlinear magnet design. The ring optics control has challenging requirements that reach or exceed the present state of the art. The development of a complete self-consistent design of the IOTA ring optics, meeting the demands of all planned AARD experiments, is presented. Of particular interest are the precise control for nonlinear integrable optics experiments and the transverse-to-longitudinal coupling and phase stability for the Optical Stochastic Cooling Experiment (OSC). Since the beam time-of-flight must be tightly controlled in the OSC section, studies of second order corrections in this section are presented.

  8. High Frequency, High Gradient Dielectric Wakefield Acceleration Experiments at SLAC and BNL

    SciTech Connect

    Rosenzweig, J. B.; Andonian, G.; Niknejadi, P.; Travish, G.; Williams, O.; Xuan, K.; Muggli, P.; Yakimenko, V.

    2010-11-04

    Given the recent success of >GV/m dielectric wakefield accelerator (DWA) breakdown experiments at SLAC, and follow-on coherent Cerenkov radiation (CCR) production at the UCLA Neptune, a UCLA-USC-SLAC collaboration is now implementing a new set of experiments that explore various DWA scenarios. These experiments are motivated by the opportunities presented by the approval of the FACET facility at SLAC, as well as unique pulse-train wakefield drivers at BNL. The SLAC experiments permit further exploration of the multi-GeV/m envelope in DWAs, and will entail investigations of novel materials (e.g. CVD diamond) and geometries (Bragg cylindrical structures, slab-symmetric DWAs), and have an over-riding goal of demonstrating >GeV acceleration in {approx}33 cm DWA tubes. In the nearer term before FACET's commissioning, we are performing measurements at the BNL ATF, in which we drive {approx}50-200 MV/m fields with single pulses or pulse trains, and observe resonantly driven CCR as well as deflection modes. These experiments are of high relevance to enhancing linear collider DWA designs, as they will demonstrate potential for high efficiency operation with pulse trains, and explore transverse modes for the first time.

  9. High Frequency, High Gradient Dielectric Wakefield Acceleration Experiments at SLAC and BNL

    SciTech Connect

    Rosenzweig, James; Travish, Gil; Hogan, Mark; Muggli, Patric; /Southern California U.

    2012-07-05

    Given the recent success of >GV/m dielectric wakefield accelerator (DWA) breakdown experiments at SLAC, and follow-on coherent Cerenkov radiation production at the UCLA Neptune, a UCLA-USC-SLAC collaboration is now implementing a new set of experiments that explore various DWA scenarios. These experiments are motivated by the opportunities presented by the approval of FACET facility at SLAC, as well as unique pulse-train wakefield drivers at BNL. The SLAC experiments permit further exploration of the multi-GeV/m envelope in DWAs, and will entail investigations of novel materials (e.g. CVD diamond) and geometries (Bragg cylindrical structures, slab-symmetric DWAs), and have an over-riding goal of demonstrating >GeV acceleration in {approx}33 cm DWA tubes. In the nearer term before FACET's commissioning, we are planning measurements at the BNL ATF, in which we drive {approx}50-200 MV/m fields with single pulses or pulse trains. These experiments are of high relevance to enhancing linear collider DWA designs, as they will demonstrate potential for efficient operation with pulse trains.

  10. The latest results from ELM-simulation experiments in plasma accelerators

    NASA Astrophysics Data System (ADS)

    Garkusha, I. E.; Arkhipov, N. I.; Klimov, N. S.; Makhlaj, V. A.; Safronov, V. M.; Landman, I.; Tereshin, V. I.

    2009-12-01

    Recent results of ELM-simulation experiments with quasi-stationary plasma accelerators (QSPAs) Kh-50 (Kharkov, Ukraine) and QSPA-T (Troitsk, Russia) as well as experiments in the pulsed plasma gun MK-200UG (Troitsk, Russia) are discussed. Primary attention in Troitsk experiments has been focused on investigating the carbon-fibre composite (CFC) and tungsten erosion mechanisms, their onset conditions and the contribution of various erosion mechanisms (including droplet splashing) to the resultant surface damage at varying plasma heat flux. The obtained results are used for validating the numerical codes PEGASUS and MEMOS developed in FZK. Crack patterns and residual stresses in tungsten targets under repetitive edge localized mode (ELM)-like plasma pulses are studied in simulation experiments with QSPA Kh-50. Statistical processing of the experimental results on crack patterns after different numbers of QSPA Kh-50 exposures as well as those on the dependence of cracking on the heat load and surface temperature is performed.

  11. 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. PMID:26487675

  12. 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

  13. STS-40 orbital acceleration research experiment flight results during a typical sleep period

    NASA Technical Reports Server (NTRS)

    Blanchard, R. C.; Nicholson, J. Y.; Ritter, J. R.

    1992-01-01

    The Orbital Acceleration Research Experiment (OARE), an electrostatic accelerometer package with complete on-orbit calibration capabilities, was flown for the first time aboard the Space Shuttle on STS-40. This is also the first time an accelerometer package with nano-g sensitivity and a calibration facility has flown aboard the Space Shuttle. The instrument is designed to measure and record the Space Shuttle aerodynamic acceleration environment from the free molecule flow regime through the rarified flow transition into the hypersonic continuum regime. Because of its sensitivity, the OARE instrument defects aerodynamic behavior of the Space Shuttle while in low-earth orbit. A 2-hour orbital time period on day seven of the mission, when the crew was asleep and other spacecraft activities were at a minimum, was examined. During the flight, a 'trimmed-mean' filter was used to produce high quality, low frequency data which was successfully stored aboard the Space Shuttle in the OARE data storage system. Initial review of the data indicated that, although the expected precision was achieved, some equipment problems occurred resulting in uncertain accuracy. An acceleration model which includes aerodynamic, gravity-gradient, and rotational effects was constructed and compared with flight data. Examination of the model with the flight data shows the instrument to be sensitive to all major expected low frequency acceleration phenomena; however, some erratic instrument bias behavior persists in two axes. In these axes, the OARE data can be made to match a comprehensive atmospheric-aerodynamic model by making bias adjustments and slight linear corrections for drift. The other axis does not exhibit these difficulties and gives good agreement with the acceleration model.

  14. 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. PMID:24121970

  15. 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

  16. Emotional Experience Improves With Age: Evidence Based on Over 10 Years of Experience Sampling

    PubMed Central

    Carstensen, Laura L.; Turan, Bulent; Scheibe, Susanne; Ram, Nilam; Ersner-Hershfield, Hal; Samanez-Larkin, Gregory R.; Brooks, Kathryn P.; Nesselroade, John R.

    2012-01-01

    Recent evidence suggests that emotional well-being improves from early adulthood to old age. This study used experience-sampling to examine the developmental course of emotional experience in a representative sample of adults spanning early to very late adulthood. Participants (N = 184, Wave 1; N = 191, Wave 2; N = 178, Wave 3) reported their emotional states at five randomly selected times each day for a one week period. Using a measurement burst design, the one-week sampling procedure was repeated five and then ten years later. Cross-sectional and growth curve analyses indicate that aging is associated with more positive overall emotional well-being, with greater emotional stability and with more complexity (as evidenced by greater co-occurrence of positive and negative emotions). These findings remained robust after accounting for other variables that may be related to emotional experience (personality, verbal fluency, physical health, and demographic variables). Finally, emotional experience predicted mortality; controlling for age, sex, and ethnicity, individuals who experienced relatively more positive than negative emotions in everyday life were more likely to have survived over a 13 year period. Findings are discussed in the theoretical context of socioemotional selectivity theory. PMID:20973600

  17. Emotional experience improves with age: evidence based on over 10 years of experience sampling.

    PubMed

    Carstensen, Laura L; Turan, Bulent; Scheibe, Susanne; Ram, Nilam; Ersner-Hershfield, Hal; Samanez-Larkin, Gregory R; Brooks, Kathryn P; Nesselroade, John R

    2011-03-01

    Recent evidence suggests that emotional well-being improves from early adulthood to old age. This study used experience-sampling to examine the developmental course of emotional experience in a representative sample of adults spanning early to very late adulthood. Participants (N = 184, Wave 1; N = 191, Wave 2; N = 178, Wave 3) reported their emotional states at five randomly selected times each day for a one week period. Using a measurement burst design, the one-week sampling procedure was repeated five and then ten years later. Cross-sectional and growth curve analyses indicate that aging is associated with more positive overall emotional well-being, with greater emotional stability and with more complexity (as evidenced by greater co-occurrence of positive and negative emotions). These findings remained robust after accounting for other variables that may be related to emotional experience (personality, verbal fluency, physical health, and demographic variables). Finally, emotional experience predicted mortality; controlling for age, sex, and ethnicity, individuals who experienced relatively more positive than negative emotions in everyday life were more likely to have survived over a 13 year period. Findings are discussed in the theoretical context of socioemotional selectivity theory. PMID:20973600

  18. Beryllium liner implosion experiments on the Z accelerator in preparation for magnetized liner inertial fusiona)

    NASA Astrophysics Data System (ADS)

    McBride, R. D.; Martin, M. R.; Lemke, R. W.; Greenly, J. B.; Jennings, C. A.; Rovang, D. C.; Sinars, D. B.; Cuneo, M. E.; Herrmann, M. C.; Slutz, S. A.; Nakhleh, C. W.; Ryutov, D. D.; Davis, J.-P.; Flicker, D. G.; Blue, B. E.; Tomlinson, K.; Schroen, D.; Stamm, R. M.; Smith, G. E.; Moore, J. K.; Rogers, T. J.; Robertson, G. K.; Kamm, R. J.; Smith, I. C.; Savage, M.; Stygar, W. A.; Rochau, G. A.; Jones, M.; Lopez, M. R.; Porter, J. L.; Matzen, M. K.

    2013-05-01

    Multiple experimental campaigns have been executed to study the implosions of initially solid beryllium (Be) liners (tubes) on the Z pulsed-power accelerator. The implosions were driven by current pulses that rose from 0 to 20 MA in either 100 or 200 ns (200 ns for pulse shaping experiments). These studies were conducted in support of the recently proposed Magnetized Liner Inertial Fusion concept [Slutz et al., Phys. Plasmas 17, 056303 (2010)], as well as for exploring novel equation-of-state measurement techniques. The experiments used thick-walled liners that had an aspect ratio (initial outer radius divided by initial wall thickness) of either 3.2, 4, or 6. From these studies, we present three new primary results. First, we present radiographic images of imploding Be liners, where each liner contained a thin aluminum sleeve for enhancing the contrast and visibility of the liner's inner surface in the images. These images allow us to assess the stability of the liner's inner surface more accurately and more directly than was previously possible. Second, we present radiographic images taken early in the implosion (prior to any motion of the liner's inner surface) of a shockwave propagating radially inward through the liner wall. Radial mass density profiles from these shock compression experiments are contrasted with profiles from experiments where the Z accelerator's pulse shaping capabilities were used to achieve shockless ("quasi-isentropic") liner compression. Third, we present "micro-Ḃ" measurements of azimuthal magnetic field penetration into the initially vacuum-filled interior of a shocked liner. Our measurements and simulations reveal that the penetration commences shortly after the shockwave breaks out from the liner's inner surface. The field then accelerates this low-density "precursor" plasma to the axis of symmetry.

  19. Beryllium liner implosion experiments on the Z accelerator in preparation for magnetized liner inertial fusion

    SciTech Connect

    McBride, R. D.; Martin, M. R.; Lemke, R. W.; Jennings, C. A.; Rovang, D. C.; Sinars, D. B.; Cuneo, M. E.; Herrmann, M. C.; Slutz, S. A.; Nakhleh, C. W.; Davis, J.-P.; Flicker, D. G.; Rogers, T. J.; Robertson, G. K.; Kamm, R. J.; Smith, I. C.; Savage, M.; Stygar, W. A.; Rochau, G. A.; Jones, M.; and others

    2013-05-15

    Multiple experimental campaigns have been executed to study the implosions of initially solid beryllium (Be) liners (tubes) on the Z pulsed-power accelerator. The implosions were driven by current pulses that rose from 0 to 20 MA in either 100 or 200 ns (200 ns for pulse shaping experiments). These studies were conducted in support of the recently proposed Magnetized Liner Inertial Fusion concept [Slutz et al., Phys. Plasmas 17, 056303 (2010)], as well as for exploring novel equation-of-state measurement techniques. The experiments used thick-walled liners that had an aspect ratio (initial outer radius divided by initial wall thickness) of either 3.2, 4, or 6. From these studies, we present three new primary results. First, we present radiographic images of imploding Be liners, where each liner contained a thin aluminum sleeve for enhancing the contrast and visibility of the liner's inner surface in the images. These images allow us to assess the stability of the liner's inner surface more accurately and more directly than was previously possible. Second, we present radiographic images taken early in the implosion (prior to any motion of the liner's inner surface) of a shockwave propagating radially inward through the liner wall. Radial mass density profiles from these shock compression experiments are contrasted with profiles from experiments where the Z accelerator's pulse shaping capabilities were used to achieve shockless (“quasi-isentropic”) liner compression. Third, we present “micro-B-dot ” measurements of azimuthal magnetic field penetration into the initially vacuum-filled interior of a shocked liner. Our measurements and simulations reveal that the penetration commences shortly after the shockwave breaks out from the liner's inner surface. The field then accelerates this low-density “precursor” plasma to the axis of symmetry.

  20. Design and fabrication of plasma accelerator for space micro-debris simulation and preliminary experiment

    NASA Astrophysics Data System (ADS)

    Han, J.; Zhang, Z.; Huang, J.; Li, X.; Chen, Z.; Quan, R.

    A simulation facility for hypervelocity impact of space micro-debris is designed and fabricated Just after the assembly of the facility some preliminary debugging experiments have conducted A plasma accelerator is the core component of the facility which composed of a coaxial discharge electrode an electromagnetic compressing coil and a nozzle The coaxial electrode is discharged synchronously by pulse injected gas from a delicate fabricated electromagnetic valve and pulse voltage from a capacitance bank The time periods for the pulse gas valve to turn on and to feed gas are 400 and 900 microseconds respectively As to the capacitance bank the maximum capacity is 512 mu F and can be charged as high as 30kV Therefore the maximum energy storage for the capacitance and discharge is 230KJ A custom designed control circuit ignites the pulse valve and discharge switch in turn Then a block of plasma is produced and accelerated into the electromagnetic coil where the plasma is compressed denser Eventually a plasma flow with high pressure and temperature is sprayed out the nozzle which pushes a cluster of micro-particles attached closely to the nozzle exit to hypervelocity During the preliminary debugging experiment 128 mu F capacitance is charged to 15kV and 400kA discharge current is generated then glass spheres with 100 mu m diameter is accelerated to 4 3km s Now the debug for the facility is still in progress in the near future it can accelerate micro-particles to higher velocity

  1. Electromagnetic Safety of Spacecraft During Active Experiments with the Use of Plasma Accelerators and Ion Injectors

    NASA Astrophysics Data System (ADS)

    Plokhikh, Andrey; Popov, Garri; Shishkin, Gennady; Antropov, Nikolay; Vazhenin, Nikolay; Soganova, Galina

    Works under the development and application of stationary and pulsed plasma accelerators of charged particles conducted at the Moscow Aviation Institute and Research Institute of Applied Mechanics and Electrodynamics during over 40 years, active experiments on board meteorological rockets, artificial Earth satellites and "Mir" orbital station including [1], allowed to obtain data on the influence of pulsed and continuous plasma injection with the given parameters on the drop of energetic particles out of the radiation belts, efficiency of artificial excitation and propagation of electromagnetic waves in ELF and VLF ranges, and evolution of artificial plasma formations in different regions of ionosphere. Variation of the near-spacecraft electromagnetic environment related to the operation of plasma injectors was registered during active experiments along with the global electrodynamic processes. The measured electromagnetic fields are of rather high intensity and occupy frequency spectrum from some Hz to tens of GHz that may be of definite danger for the operation of spacecraft and its onboard systems. Analysis for the known test data is presented in the paper and methods are discussed for the diagnostics and modeling under laboratory conditions of radiative processes proceeding at the operation of plasma accelerators and ion injectors used while making active space experiments. Great attention is paid to the methodological and metrological bases for making radio measurements in vacuum chambers, design concept and hardware configuration of ground special-purpose instrumentation scientific complexes [2]. Basic requirements are formulated for the measurements and analysis of electromagnetic fields originating during the operation of plasma accelerators, including the radiative induced and conductive components inside the spacecraft, as well as the wave emission and excitation outside the spacecraft, in the ionosphere including. Measurement results for the intrinsic

  2. Measurements of fusion neutrons from Magnetized Liner Inertial Fusion Experiments on the Z accelerator

    NASA Astrophysics Data System (ADS)

    Hahn, K. D.; Chandler, G. A.; Ruiz, C. L.; Gomez, M. R.; Slutz, S. A.; Sefkow, A. B.; Sinars, D. B.; Hansen, S. B.; Knapp, P. F.; Schmit, P. F.; Harding, E. C.; Awe, T. J.; Torres, J. A.; Jones, B.; Bur, J. A.; Cooper, G. W.; Styron, J. D.; Glebov, V. Yu.

    2015-11-01

    Strong evidence of thermonuclear neutron production has been observed during Magnetized Liner Inertial Fusion (MagLIF) experiments on the Z accelerator. So far, these experiments have utilized deuterium fuel and produced primary DD fusion neutron yields up to 2e12 with electron and ion stagnation temperatures in the 2-3 keV range. We present MagLIF neutron measurements and compare to other data and implosion simulations. In addition to primary DD and secondary DT yields and ion temperatures, other complex physics regarding the degree of fuel magnetization and liner density are elucidated by the neutron measurements. Neutron diagnostic development for deuterium and future deuterium-tritium fuel experiments are also discussed. Sandia is sponsored by the U.S. DOE's NNSA under contract DE-AC04-94AL85000.

  3. An Ultra-High Gradient Cherenkov Wakefield Acceleration Experiment at SLAC FFTB

    SciTech Connect

    Rosenzweig, J.B.; Hoover, S.; Hogan, M.J.; Muggli, P.; Thompson, M.; Travish, G.; Yoder, R.; /UCLA /SLAC /Southern California U.

    2005-08-02

    The creation of ultra-high current, ultra-short pulse beams Q=3 nC, {sigma}{sub z} = 20{micro}m at the SLAC FFTB has opened the way for very high gradient plasma wakefield acceleration experiments. We study here the use of these beams in a proposed Cherenkov wakefield experiment, where one may excite electromagnetic wakes in a simple dielectric tube with inner diameter of few 100 microns that exceed the GV/m level. We discuss the scaling of the fields with design geometric design parameters, and choice of dielectric. We also examine measurable aspects of the experiment, such as the total coherent Cerenkov radiation energy one may collect, and the expected aspects of dielectric breakdown at high fields.

  4. Ageing studies of wavelength shifter fibers for the TILECAL/ATLAS experiment

    NASA Astrophysics Data System (ADS)

    Silva, J.; Maio, A.; Pina, J.; Santos, J.; Saraiva, J. G.

    2007-09-01

    Natural and accelerated ageing studies for the different components of the TILECAL calorimeter, of the ATLAS experiment, play a central role in forecasting the evolution of the detector's performance throughout its operating life. It is possible that the operation of ATLAS will be extended by 5 years in an upgraded LHC scenario. Such prospect makes these studies even more important, in order to assess the contribution of the natural ageing in relation to the other processes inducing performance loss in the optical components. Among other activities in this LHC/CERN collaboration, the Lisbon calorimetry group is involved in studying the impact of radiation damage and natural ageing in optical characteristics of the TILECAL wavelength shifter (WLS) optical fibers and scintillators, and to reevaluate the light budget of the tile/fiber system. The light yield and the attenuation length of the WLS and scintillating optical fibers are measured using an X- Y table. Results are presented for several sets of WLS optical fibers (Kuraray Y11(200)MSJ) whose characteristics have been monitored since 1999. Most of those 338 fibers are from the mass production for the TILECAL detector: 208 non-aluminized 200 cm fibers, from several production batches, and 128 batch #6 aluminized fibers, with lengths ranging from 114 to 207 cm.

  5. 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.

  6. 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

  7. Investigation of neutrino oscillations in the T2k long-baseline accelerator experiment

    SciTech Connect

    Izmaylov, A. O. Yershov, N. V.; Kudenko, Yu. G.; Matveev, V. A.; Mineev, O. V.; Musienko, Yu. V.; Khabibulliun, M. M.; Khotjantsev, A. N.; Shaykhiev, A. T.

    2012-02-15

    High-sensitivity searches for transitions of muon neutrinos to electron neutrinos are the main task of the T2K (Tokai-to-Kamioka) second-generation long-baseline accelerator neutrino experiment. The present article is devoted to describing basic principles of T2K, surveying experimental apparatuses that it includes, and considering in detail the muon-range detector (SMRD) designed and manufactured by a group of physicists from the Institute of Nuclear Research (Russian Academy of Sciences, Moscow). The results of the first measurements with a neutrino beam are presented, and plans for the near future are discussed.

  8. Turbulent Magnetohydrodynamic Acceleration Processes: Theory SSX Experiments and Connections to Space and Astrophysics

    SciTech Connect

    W Matthaeus; M Brown

    2006-07-15

    This is the final technical report for a funded program to provide theoretical support to the Swarthmore Spheromak Experiment. We examined mhd relaxation, reconnecton between two spheromaks, particle acceleration by these processes, and collisonless effects, e.g., Hall effect near the reconnection zone,. Throughout the project, applications to space plasma physics and astrophysics were included. Towards the end ofthe project we were examining a more fully turbulent relaxation associated with unconstrained dynamics in SSX. We employed experimental, spacecraft observations, analytical and numerical methods.

  9. Vibration isolation technology: Sensitivity of selected classes of space experiments to residual accelerations

    NASA Technical Reports Server (NTRS)

    Alexander, J. Iwan D.; Zhang, Y. Q.; Adebiyi, Adebimpe

    1989-01-01

    Progress performed on each task is described. Order of magnitude analyses related to liquid zone sensitivity and thermo-capillary flow sensitivity are covered. Progress with numerical models of the sensitivity of isothermal liquid zones is described. Progress towards a numerical model of coupled buoyancy-driven and thermo-capillary convection experiments is also described. Interaction with NASA personnel is covered. Results to date are summarized and they are discussed in terms of the predicted space station acceleration environment. Work planned for the second year is also discussed.

  10. The UCLA/SLAC Ultra-High Gradient Cerenkov Wakefield Accelerator Experiment

    SciTech Connect

    Thompson, M.C.; Badakov, H.; Rosenzweig, J.B.; Travish, G.; Hogan, M.; Ischebec, R.; Siemann, R.; Walz, D.; Scott, A.; Yoder, R.; /Manhattan Coll., Riverdale

    2006-01-25

    An experiment is planned to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range. This new UCLA/SLAC/USC collaboration will take advantage of the unique SLAC FFTB electron beam and its demonstrated ultra-short pulse lengths and high currents (e.g., {delta}{sub z} = 20 {micro}m at Q = 3 nC). The electron beam will be focused down and sent through varying lengths of fused silica capillary tubing with two different sizes: ID = 200 {micro}m/OD = 325 {micro}m and ID = 100 {micro}m/OD = 325 {micro}m. The pulse length of the electron beam will be varied in order to alter the accelerating gradient and probe the breakdown threshold of the dielectric structures. In addition to breakdown studies, we plan to collect and measure coherent Cerenkov radiation emitted from the capillary tube to gain information about the strength of the accelerating fields.

  11. High rates of carbon storage in old deciduous forests: Emerging mechanisms from the Forest Accelerated Succession ExperimenT (FASET)

    NASA Astrophysics Data System (ADS)

    Gough, C. M.; Nave, L. E.; Hardiman, B. S.; Bohrer, G.; Halperin, A.; Maurer, K.; Le Moine, J.; Nadelhoffer, K.; Vogel, C. S.; Curtis, P.; University Of Michigan Biological Station Forest Ecosystem Study (Umbs-Fest) Team

    2010-12-01

    Deciduous forests of the eastern US are broadly approaching an ecological threshold in which early successional dominant trees are senescing and giving way to later successional species, with unknown consequences for regional carbon (C) cycling. Though recent research demonstrates that forests may accumulate C for centuries, the mechanisms behind sustained rates of C storage in old, particularly deciduous, forests have not been identified. In a regionally representative forest at the University of Michigan Biological Station, we are combining observational and experimental C cycling studies to forecast how forest C storage responds to climate variation, disturbance, and succession. The Forest Accelerated Succession ExperimenT (FASET), in which >6,700 aspen and birch trees (~35 % LAI) were stem girdled within a 39 ha area, is testing the hypothesis that forest production will increase rather than decline with age, due to increases in nitrogen (N) availability, N allocation to the canopy, and the concurrent development of a more biologically and structurally complex canopy. Results thus far support our hypothesis that aging forests in the region may sustain high rates of C storage through shifts in N cycling and increased canopy complexity. Girdling-induced mortality of early successional species reduced soil respiration, accelerated fine root turnover, and prompted the redistribution of N from the foliage of early to later successional species. Nitrogen redistribution increased leaf area index (LAI) production by later successional species, offsetting declines in LAI from senescing early successional species. High rates of net primary production (NPP) were sustained in stands comprising a diverse assemblage of early and later successional species because later successional species, when already present in the canopy, rapidly compensated for declining growth of early successional species. Canopy structural complexity, which increased with forest age, was positively

  12. Nitrogen compounds in wine during its biological aging by two flor film yeasts: An approach to accelerated biological aging of dry sherry-type wines.

    PubMed

    Mauricio, J C; Ortega, J M

    1997-01-20

    Urea, ammonium, and free amino acid contents were quantified in biological aging of a young wine under two flor film forming yeast strains, Saccharomyces cerevisiae race capensis and S. cerevisiae race bayanus, and compared. Cell viability in the film was different for the two yeast strains. Thus, capensis maintained a much greater number of viable cells per surface area than bayanus and hence used greater amount of nitrogen compounds. The main source of nitrogen for the yeasts during the biological aging process was L-proline. The two yeast strains also differed in the amounts of assimilable nitrogen they utilized, in their preferences for amino acid consumption, and kinetics. To accelerate the aging process, the effect of controlled monthly aeration of the wine aged with capensis strain was investigated. The results revealed that short aeration did not appreciably increase the overall consumption of assimilable nitrogen, but consumption of some nitrogen compounds was accelerated (particularly L-proline, L-tryptophan, L-glutamic acid, ammonium ion, L-lysine, and L-arginine); the use of L-ornithine was inhibited; and GABA, L-methionine, and urea were depletes. Probably the aeration increases the aroma compounds, thereby producing wines with improved sensory properties. (c) 1997 John Wiley & Sons, Inc. PMID:18633960

  13. Experimental characterization of a coaxial plasma accelerator for a colliding plasma experiment

    NASA Astrophysics Data System (ADS)

    Wiechula, J.; Hock, C.; Iberler, M.; Manegold, T.; Schönlein, A.; Jacoby, J.

    2015-04-01

    We report experimental results of a single coaxial plasma accelerator in preparation for a colliding plasma experiment. The utilized device consisted of a coaxial pair of electrodes, accelerating the plasma due to J ×B forces. A pulse forming network, composed of three capacitors connected in parallel, with a total capacitance of 27 μF was set up. A thyratron allowed to switch the maximum applied voltage of 9 kV. Under these conditions, the pulsed currents reached peak values of about 103 kA. The measurements were performed in a small vacuum chamber with a neutral-gas prefill at gas pressures between 10 Pa and 14 000 Pa. A gas mixture of ArH2 with 2.8% H2 served as the discharge medium. H2 was chosen in order to observe the broadening of the Hβ emission line and thus estimate the electron density. The electron density for a single plasma accelerator reached peak values on the order of 1016 cm-3 . Electrical parameters, inter alia inductance and resistance, were determined for the LCR circuit during the plasma acceleration as well as in a short circuit case. Depending on the applied voltage, the inductance and resistance reached values ranging from 194 nH to 216 nH and 13 mΩ to 23 mΩ, respectively. Furthermore, the plasma velocity was measured using a fast CCD camera. Plasma velocities of 2 km/s up to 17 km/s were observed, the magnitude being highly correlated with gas pressure and applied voltage.

  14. Experimental characterization of a coaxial plasma accelerator for a colliding plasma experiment

    SciTech Connect

    Wiechula, J.; Hock, C.; Iberler, M.; Manegold, T.; Schönlein, A.; Jacoby, J.

    2015-04-15

    We report experimental results of a single coaxial plasma accelerator in preparation for a colliding plasma experiment. The utilized device consisted of a coaxial pair of electrodes, accelerating the plasma due to J×B forces. A pulse forming network, composed of three capacitors connected in parallel, with a total capacitance of 27 μF was set up. A thyratron allowed to switch the maximum applied voltage of 9 kV. Under these conditions, the pulsed currents reached peak values of about 103 kA. The measurements were performed in a small vacuum chamber with a neutral-gas prefill at gas pressures between 10 Pa and 14 000 Pa. A gas mixture of ArH{sub 2} with 2.8% H{sub 2} served as the discharge medium. H{sub 2} was chosen in order to observe the broadening of the H{sub β} emission line and thus estimate the electron density. The electron density for a single plasma accelerator reached peak values on the order of 10{sup 16} cm{sup −3}. Electrical parameters, inter alia inductance and resistance, were determined for the LCR circuit during the plasma acceleration as well as in a short circuit case. Depending on the applied voltage, the inductance and resistance reached values ranging from 194 nH to 216 nH and 13 mΩ to 23 mΩ, respectively. Furthermore, the plasma velocity was measured using a fast CCD camera. Plasma velocities of 2 km/s up to 17 km/s were observed, the magnitude being highly correlated with gas pressure and applied voltage.

  15. Effects of Experiment Location and Orbiter Attitude on the Residual Acceleration On-Board STS-73 (USML-2)

    NASA Technical Reports Server (NTRS)

    Hakimzadeh, Roshanak; McPherson, Kevin M.; Matisak, Brian P.; Wagar, William O.

    1997-01-01

    A knowledge of the quasi-steady acceleration environment on the NASA Space Shuttle Orbiter is of particular importance for materials processing experiments which are limited by slow diffusive processes. The quasi-steady (less than 1 HZ) acceleration environment on STS-73 (USML-2) was measured using the Orbital Acceleration Research Experiment (OARE) accelerometer. One of the facilities flown on USML-2 was the Crystal Growth Furnace (CGF), which was used by several Principal Investigators (PIS) to grow crystals. In this paper the OARE data mapped to the sample melt location within this furnace is presented. The ratio of the axial to radial components of the quasi-steady acceleration at the melt site is presented. Effects of Orbiter attitude on the acceleration data is discussed.

  16. 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

  17. 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

  18. The 7-gap-resonator-accelerator for the REX-ISOLDE-experiment at CERN

    NASA Astrophysics Data System (ADS)

    Podlech, H.; Grieser, M.; von Hahn, R.; Papureanu, S.; Repnow, R.; Schwalm, D.

    1998-04-01

    The Radioactive Beam Experiment at ISOLDE (REX-ISOLDE-Experiment) which presently is being developed and under construction at CERN serves to investigate exotic, very neutron rich, radioactive nuclei [1](Radioactive beam EXperiment at ISOLDE: Coloumb Excitation and Neutron Transfer Reactions of Exotic Nuclei, Proposal to the ISOLDE commitee, CERNSIC94-25). A linear accelerator delivers radioactive ions which are produced by the isotope separator ISOLDE with energies between 0.85 and 2.2 MeV/u. The Linac will consist of a RFQ-accelerator, an interdigital H-Structure (IH) and three 7-gap-resonators with variable energy. While the LMU Munich is responsible for the frontpart of the accelerator, the backpart is being built by the MPI [2](H. Podlech, Master Thesis, MPI-H-V21-1997, Heidelburg, 1997). After estimation of the voltage of one resonator to 1.75 MV at 90 kW, the design velocities were fixed to 5.4%, 6.0% and 6.6% of the velocity of light. Three downscaled models (1:2.5) were built in order to optimize the shuntimpedance and the field-distribution at the operation frequency of the amplifiers of 101.28 MHz. The optimization of all low power resonators is now successfully finished. Extensive beam dynamic calculations were made in order to optimize the transmission of the beam up to the target. It turned out that final energies between 0.85 and 2.2 MeV/u with nearly 100% transmission can be achieved. The acceptance in the x-plane is 1.2π mm mrad (norm.) and in the y-plane 3.0π mm mrad (norm.). The bunchlength of the fully accelerated beam (2.2 MeV/u) is 2.4 ns at the target. The development of the resonators was accompanied by extensive MAFIA calculations. It could be demonstrated that spiral-resonators like 7-gap-resonators can be calculated with MAFIA with an accuracy of 1% in comparison with experimental results. Presently, the tanks and the half shells of the power type resonators are manufactured in the workshops of the MPI.

  19. Test particle acceleration in a numerical MHD experiment of an anemone jet

    NASA Astrophysics Data System (ADS)

    Rosdahl, K. J.; Galsgaard, K.

    2010-02-01

    Aims: To use a 3D numerical MHD experiment representing magnetic flux emerging into an open field region as a background field for tracing charged particles. The interaction between the two flux systems generates a localised current sheet where MHD reconnection takes place. We investigate how efficiently the reconnection region accelerates charged particles and what kind of energy distribution they acquire. Methods: The particle tracing is done numerically using the Guiding Center Approximation on individual data sets from the numerical MHD experiment. Results: We derive particle and implied photon distribution functions having power law forms, and look at the impact patterns of particles hitting the photosphere. We find that particles reach energies far in excess of those seen in observations of solar flares. However the structure of the impact region in the photosphere gives a good representation of the topological structure of the magnetic field. Three movies are only available in electronic form at http://www.aanda.org

  20. Recent accelerator experiments updates in Shielding INtegral Benchmark Archive Database (SINBAD)

    NASA Astrophysics Data System (ADS)

    Kodeli, I.; Sartori, E.; Kirk, B.

    2006-06-01

    SINBAD is an internationally established set of radiation shielding and dosimetry data relative to experiments relevant in reactor shielding, fusion blanket neutronics and accelerator shielding. In addition to the characterization of the radiation source, it describes shielding materials and instrumentation and the relevant detectors. The experimental results, be it dose, reaction rates or unfolded spectra are presented in tabular ASCII form that can easily be exported to different computer environments for further use. Most sets in SINBAD also contain the computer model used for the interpretation of the experiment and, where available, results from uncertainty analysis. The set of primary documents used for the benchmark compilation and evaluation are provided in computer readable form. SINBAD is available free of charge from RSICC and from the NEA Data Bank.

  1. Fusion-neutron measurements for magnetized liner inertial fusion experiments on the Z accelerator

    NASA Astrophysics Data System (ADS)

    Hahn, K. D.; Chandler, G. A.; Ruiz, C. L.; Cooper, G. W.; Gomez, M. R.; Slutz, S.; Sefkow, A. B.; Sinars, D. B.; Hansen, S. B.; Knapp, P. F.; Schmit, P. F.; Harding, E.; Jennings, C. A.; Awe, T. J.; Geissel, M.; Rovang, D. C.; Torres, J. A.; Bur, J. A.; Cuneo, M. E.; Glebov, V. Yu; Harvey-Thompson, A. J.; Herrman, M. C.; Hess, M. H.; Johns, O.; Jones, B.; Lamppa, D. C.; Lash, J. S.; Martin, M. R.; McBride, R. D.; Peterson, K. J.; Porter, J. L.; Reneker, J.; Robertson, G. K.; Rochau, G. A.; Savage, M. E.; Smith, I. C.; Styron, J. D.; Vesey, R. A.

    2016-05-01

    Several magnetized liner inertial fusion (MagLIF) experiments have been conducted on the Z accelerator at Sandia National Laboratories since late 2013. Measurements of the primary DD (2.45 MeV) neutrons for these experiments suggest that the neutron production is thermonuclear. Primary DD yields up to 3e12 with ion temperatures ∼2-3 keV have been achieved. Measurements of the secondary DT (14 MeV) neutrons indicate that the fuel is significantly magnetized. Measurements of down-scattered neutrons from the beryllium liner suggest ρRliner∼1g/cm2. Neutron bang times, estimated from neutron time-of-flight (nTOF) measurements, coincide with peak x-ray production. Plans to improve and expand the Z neutron diagnostic suite include neutron burn-history diagnostics, increased sensitivity and higher precision nTOF detectors, and neutron recoil-based yield and spectral measurements.

  2. Application of an electromagnetic accelerator to ultra-high-speed plastic deformation experiments

    NASA Astrophysics Data System (ADS)

    Okada, A.; Kiritani, M.

    2002-01-01

    An electromagnetic accelerator (railgun) is briefly introduced, and several examples of experimental results obtained from test runs of this facility are shown and merits of the application of the railgun to high-speed deformation experiments are emphasized. On applying this facility to high-speed deformation experiments, several specific adapters should be designed, such as a jig for applying a designed amount of deformation to a specimen, A specimen cooling system is also important, as a measure against severe temperature rise occurring during extraordinarily rapid deformation. Although application of the railgun involves many difficulties, the railgun is expected to be a very attractive tool for ultra-high-speed deformation research. The railgun can realize the ultra-high-speed deformation via the collision of a projectile and a target material at a speed comparable to the sonic wave velocity Such high speeds cannot be obtainable by other methods.

  3. 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

  4. When does brain aging accelerate? Dangers of quadratic fits in cross-sectional studies.

    PubMed

    Fjell, Anders M; Walhovd, Kristine B; Westlye, Lars T; Østby, Ylva; Tamnes, Christian K; Jernigan, Terry L; Gamst, Anthony; Dale, Anders M

    2010-05-01

    Many brain structures show a complex, non-linear pattern of maturation and age-related change. Often, quadratic models (beta(0) + beta(1)age + beta(2)age(2) + epsilon) are used to describe such relationships. Here, we demonstrate that the fitting of quadratic models is substantially affected by seemingly irrelevant factors, such as the age-range sampled. Hippocampal volume was measured in 434 healthy participants between 8 and 85 years of age, and quadratic models were fit to subsets of the sample with different age-ranges. It was found that as the bottom of the age-range increased, the age at which volumes appeared to peak was moved upwards and the estimated decline in the last part of the age-span became larger. Thus, whether children were included or not affected the estimated decline between 60 and 85 years. We conclude that caution should be exerted in inferring age-trajectories from global fit models, e.g. the quadratic model. A nonparametric local smoothing technique (the smoothing spline) was found to be more robust to the effects of different starting ages. The results were replicated in an independent sample of 309 participants. PMID:20109562

  5. Physical processes at work in sub-30 fs, PW laser pulse-driven plasma accelerators: Towards GeV electron acceleration experiments at CILEX facility

    NASA Astrophysics Data System (ADS)

    Beck, A.; Kalmykov, S. Y.; Davoine, X.; Lifschitz, A.; Shadwick, B. A.; Malka, V.; Specka, A.

    2014-03-01

    Optimal regimes and physical processes at work are identified for the first round of laser wakefield acceleration experiments proposed at a future CILEX facility. The Apollon-10P CILEX laser, delivering fully compressed, near-PW-power pulses of sub-25 fs duration, is well suited for driving electron density wakes in the blowout regime in cm-length gas targets. Early destruction of the pulse (partly due to energy depletion) prevents electrons from reaching dephasing, limiting the energy gain to about 3 GeV. However, the optimal operating regimes, found with reduced and full three-dimensional particle-in-cell simulations, show high energy efficiency, with about 10% of incident pulse energy transferred to 3 GeV electron bunches with sub-5% energy spread, half-nC charge, and absolutely no low-energy background. This optimal acceleration occurs in 2 cm length plasmas of electron density below 1018 cm-3. Due to their high charge and low phase space volume, these multi-GeV bunches are tailor-made for staged acceleration planned in the framework of the CILEX project. The hallmarks of the optimal regime are electron self-injection at the early stage of laser pulse propagation, stable self-guiding of the pulse through the entire acceleration process, and no need for an external plasma channel. With the initial focal spot closely matched for the nonlinear self-guiding, the laser pulse stabilizes transversely within two Rayleigh lengths, preventing subsequent evolution of the accelerating bucket. This dynamics prevents continuous self-injection of background electrons, preserving low phase space volume of the bunch through the plasma. Near the end of propagation, an optical shock builds up in the pulse tail. This neither disrupts pulse propagation nor produces any noticeable low-energy background in the electron spectra, which is in striking contrast with most of existing GeV-scale acceleration experiments.

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

    DOE PAGESBeta

    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

  7. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2004-06-01

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

  9. PROPOSAL FOR A PRE-BUNCHED LASER WAKEFIELD ACCELERATION EXPERIMENT AT THE BNL DUV FEL FACILITY.

    SciTech Connect

    WANG,X.J.SHEEHY,B.WU,Z.GAI,W.TING,A.

    2003-05-12

    We propose a pre-bunched Laser Wakefield Acceleration (LWFA) experiment in a plasma channel at the BNL DUV-FEL Facility. BNL DUV-FEL facility is uniquely qualified to carry out the proposed experiment because of the high-brightness' electron beam and RF synchronized TW Ti:Sapphire laser system. The DUV-FEL is a 200 MeV linac facility equipped with a photocathode RF gun injector, a 100 fs Ti:Sapphire laser system and a magnetic bunch compressor. The proposed LWFA will inject a 150 MeV, 10 fs electron bunch into a centimeters long plasma channel. Simulation and preliminary experiment showed that, high-brightness 10 fs electron bunch with 20 pC charge could be produced using the technique of longitudinal emittance compensation. The initial experiment will be performed using the existing Ti:Sapphire laser system (50mJ, 100 fs) with 30 {micro}m spot and 4 cm channel, the maximum energy gain will be about 15 MeV. We propose to upgrade the existing SDL laser output to 500 mJ with a shorter pulse length (50 fs). For an electron beam spot size of 20 um, the expected energy gain is about 100 MeV for a 5 TW, 50 fs laser pulse.

  10. Statistical comparison between experiments and numerical simulations of shock-accelerated gas cylinders

    SciTech Connect

    Rider, William; Kamm, J. R.; Zoldi, C. A.; Tomkins, C. D.

    2002-01-01

    We present detailed spatial analysis comparing experimental data and numerical simulation results for Richtmyer-Meshkov instability experiments of Prestridge et al. and Tomkins et al. These experiments consist, respectively, of one and two diffuse cylinders of sulphur hexafluoride (SF{sub 6}) impulsively accelerated by a Mach 1.2 shockwave in air. The subsequent fluid evolution and mixing is driven by the deposition of baroclinic vorticity at the interface between the two fluids. Numerical simulations of these experiments are performed with three different versions of high resolution finite volume Godunov methods, including a new weighted adaptive Runge-Kutta (WARK) scheme. We quantify the nature of the mixing using using integral measures as well as fractal analysis and continuous wavelet transforms. Our investigation of the gas cylinder configurations follows the path of our earlier studies of the geometrically and dynamically more complex gas 'curtain' experiment. In those studies, we found significant discrepancies in the details of the experimentally measured mixing and the details of the numerical simulations. Here we evaluate the effects of these hydrodynamic integration techniques on the diffuse gas cylinder simulations, which we quantitatively compare with experimental data.

  11. TWO-STEP ACCELERATION MODEL OF COSMIC RAYS AT MIDDLE-AGED SUPERNOVA REMNANTS: UNIVERSALITY IN SECONDARY SHOCKS

    SciTech Connect

    Inoue, Tsuyoshi; Yamazaki, Ryo; Inutsuka, Shu-ichiro

    2010-11-01

    Recent gamma-ray observations of middle-aged supernova remnants revealed a mysterious broken power-law spectrum. Using three-dimensional magnetohydrodynamic simulations, we show that the interaction between a supernova blast wave and interstellar clouds formed by thermal instability generates multiple reflected shocks. The typical Mach numbers of the reflected shocks are shown to be M{approx_equal} 2 depending on the density contrast between the diffuse intercloud gas and clouds. These secondary shocks can further energize cosmic-ray particles originally accelerated at the blast-wave shock. This 'two-step' acceleration scenario reproduces the observed gamma-ray spectrum and predicts the high-energy spectral index ranging approximately from 3 to 4.

  12. Two-step Acceleration Model of Cosmic Rays at Middle-aged Supernova Remnants: Universality in Secondary Shocks

    NASA Astrophysics Data System (ADS)

    Inoue, Tsuyoshi; Yamazaki, Ryo; Inutsuka, Shu-ichiro

    2010-11-01

    Recent gamma-ray observations of middle-aged supernova remnants revealed a mysterious broken power-law spectrum. Using three-dimensional magnetohydrodynamic simulations, we show that the interaction between a supernova blast wave and interstellar clouds formed by thermal instability generates multiple reflected shocks. The typical Mach numbers of the reflected shocks are shown to be Msime 2 depending on the density contrast between the diffuse intercloud gas and clouds. These secondary shocks can further energize cosmic-ray particles originally accelerated at the blast-wave shock. This "two-step" acceleration scenario reproduces the observed gamma-ray spectrum and predicts the high-energy spectral index ranging approximately from 3 to 4.

  13. Glutamate Cysteine Ligase Modifier Subunit (Gclm) Null Mice Have Increased Ovarian Oxidative Stress and Accelerated Age-Related Ovarian Failure.

    PubMed

    Lim, Jinhwan; Nakamura, Brooke N; Mohar, Isaac; Kavanagh, Terrance J; Luderer, Ulrike

    2015-09-01

    Glutathione (GSH) is the one of the most abundant intracellular antioxidants. Mice lacking the modifier subunit of glutamate cysteine ligase (Gclm), the rate-limiting enzyme in GSH synthesis, have decreased GSH. Our prior work showed that GSH plays antiapoptotic roles in ovarian follicles. We hypothesized that Gclm(-/-) mice have accelerated ovarian aging due to ovarian oxidative stress. We found significantly decreased ovarian GSH concentrations and oxidized GSH/oxidized glutathione redox potential in Gclm(-/-) vs Gclm(+/+) ovaries. Prepubertal Gclm(-/-) and Gclm(+/+) mice had similar numbers of ovarian follicles, and as expected, the total number of ovarian follicles declined with age in both genotypes. However, the rate of decline in follicles was significantly more rapid in Gclm(-/-) mice, and this was driven by accelerated declines in primordial follicles, which constitute the ovarian reserve. We found significantly increased 4-hydroxynonenal immunostaining (oxidative lipid damage marker) and significantly increased nitrotyrosine immunostaining (oxidative protein damage marker) in prepubertal and adult Gclm(-/-) ovaries compared with controls. The percentage of small ovarian follicles with increased granulosa cell proliferation was significantly higher in prepubertal and 2-month-old Gclm(-/-) vs Gclm(+/+) ovaries, indicating accelerated recruitment of primordial follicles into the growing pool. The percentages of growing follicles with apoptotic granulosa cells were increased in young adult ovaries. Our results demonstrate increased ovarian oxidative stress and oxidative damage in young Gclm(-/-) mice, associated with an accelerated decline in ovarian follicles that appears to be mediated by increased recruitment of follicles into the growing pool, followed by apoptosis at later stages of follicular development. PMID:26083875

  14. Dating, Sex, and Substance Use as Correlates of Adolescents' Subjective Experience of Age

    ERIC Educational Resources Information Center

    Arbeau, Kelly J.; Galambos, Nancy L.; Jansson, S. Mikael

    2007-01-01

    This study examined in a random community-based sample of 664 12-19-year-olds, the relation of subjective experience of age (SEA) with chronological age, dating experience, sexual activity, and substance use. The results revealed a positive linear relation between SEA and chronological age: individuals who were chronologically older felt…

  15. 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

  16. Participation in the definition, conduct, and analysis of particle accelerator experiments for the first Spacelab Mission

    NASA Technical Reports Server (NTRS)

    Burch, J. L.

    1994-01-01

    The Space Experiments with Particle Accelerators (SEPAC) is a joint endeavor between NASA and the Institute of Space and Aeronautical Sciences (ISAS) in Japan. Its objectives are to use energetic electron beams to investigate beam-atmosphere interactions and beam-plasma interactions in the earth's upper atmosphere and ionosphere using the shuttle Spacelab. Two flights of SEPAC have occurred to date (Spacelab 1 on STS-9 in Nov.-Dec. 1983 and ATLAS 1 on STS-45 in Mar.-Apr. 1992). The SEPAC instrumentation is available for future missions, and the scientific results of the first two missions justify further investigations; however, at present there are no identifiable future flight opportunities. As specified in the contract, the primary purpose of this report is to review the scientific accomplishments of the ATLAS 1 SEPAC experiments, which have been documented in the published literature, with only a brief review of the earlier Spacelab 1 results. One of the main results of the Spacelab 1 SEPAC experiments was that the ejection of plasma from the magnetoplasmadynamic (MPD) arcjet was effective in maintaining vehicle charge neutralization during electron beam firings, but only for a brief period of 10 ms or so. Therefore, a xenon plasma contactor, which can provide continuous vehicle charge neutralization, was developed for the ATLAS 1 SEPAC experiments. Because of the successful operation of the plasma contactor on ATLAS 1, it was possible to perform experiments on beam-plasma interactions and beam-atmosphere interactions at the highest beam power levels of SEPAC. In addition, the ability of the plasma contactor to eject neutral xenon led to a successful experiment on the critical ionization velocity (CIV) phenomena on ATLAS 1.

  17. Experiments on 1,000 km/s flyer acceleration and collisions

    NASA Astrophysics Data System (ADS)

    Karasik, Max; Weaver, J. L.; Aglitskiy, Y.; Kehne, D. M.; Zalesak, S. T.; Velikovich, A. L.; Oh, J.; Serlin, V.; Obenschain, S. P.

    2012-10-01

    We will present results from follow-on experiments to the record-high velocities achieved using the ultra-uniform deep-uv drive of the Nike KrF laser [Karasik et al, Phys. Plasmas 17, 056317 (2010)], in which highly accelerated planar foils of deuterated polystyrene were made to collide with a witness foil to produce ˜1 Gbar shock pressures and result in heating of matter to thermonuclear temperatures. Such velocities may indicate a path to lower minimum energy required for central ignition. Still higher velocities and higher target densities are required for impact fast ignition. New results give velocity of >1,100 km/s achieved through improvements in pulseshaping. Variation of second foil parameters results in significant change in fusion neutron production on impact. In-flight target density is inferred from target heating upon collision via DD neutron time-of-flight ion temperature measurement. Availability of pressures generated by collisions of such highly accelerated flyers may provide an experimental platform for study of matter at extreme conditions. Work is supported by US DOE (NNSA).

  18. Laboratory Experiments with the Concordia College High-Speed Dust Particle Accelerator

    NASA Astrophysics Data System (ADS)

    Manning, H. L.

    2011-12-01

    During the Apollo Era, NASA's Goddard Space Flight Center built a 2MeV high-speed, dust particle accelerator. This facility was used to test and calibrate the LEAM instrument which was flown to the lunar surface by Apollo 17. As the Apollo project wound down, NASA no longer had need of the dust particle accelerator, and in 1975, it was move to Concordia College in Moorhead, MN. Through the years, it has been maintained and some modifications and improvements have been made to it. In the past decade, the facility has been revived and used by several collaborating institutions to study dust detector instrumentation as well as the effects of dust impacts on various materials. We have tested a prototype, space-flight dust particle detector. Also, piezoelectric pins which can be used as dust detectors were studied to learn the pin's response to single particle impacts of different energies and momenta, and then those measured responses were compared with theoretical models. The effects of high speed impacts on ultra-high temperature ceramics, aerogel, and several different thin films have also been studied at our facility. The results of these experiments will be presented.

  19. Electron Acceleration and Ionization Production in High-Power Heating Experiments at HAARP

    NASA Astrophysics Data System (ADS)

    Mishin, E. V.; Pedersen, T.

    2012-12-01

    Recent ionospheric modification experiments with the 3.6 MW transmitter at the High Frequency Active Auroral Research Program (HAARP) facility in Alaska led to discovery of artificial ionization descending from the nominal interaction altitude in the background F-region ionosphere by ~60-80 km. Artificial ionization production is indicated by significant 427.8 nm emissions from the 1st negative band of N2+ and the appearance of transmitter-induced bottomside traces in ionosonde data during the periods of most intense optical emissions. However, the exact mechanisms producing the artificial plasmas remain to be determined. Yet the only existing theoretical models explain the development of artificial plasma as an ionizing wavefront moving downward due to ionization by electrons accelerated by HF-excited strong Langmuir turbulence (SLT) generated near the plasma resonance, where the pump frequency matches the plasma frequency. However, the observations suggest also the significance of interactions with upper hybrid and electron Bernstein waves near multiples of the electron gyrofrequency. We describe recent observations and discuss suitable acceleration mechanisms.

  20. Acceleration of Dense Flowing Plasmas using ICRF Power in the VASIMR Experiment

    SciTech Connect

    Squire, Jared P.

    2005-09-26

    ICRF power in the Variable Specific Impulse Magnetoplasma Rocket (VASIMR) concept energizes ions (> 100 eV) in a diverging magnetic field to accelerate a dense ({approx} 1019 m-3) flowing plasma to velocities useful for space propulsion ({approx}100 km/s). Theory predicts that an ICRF slow wave launched from the high field side of the resonance will propagate in the magnetic beach to absorb nearly all of the power at the resonance, thus efficiently converting the RF power to ion kinetic energy. The plasma flows through the resonance only once, so the ions are accelerated in a single pass. This process has proven efficient ({approx} 70%) with an ICRF power level of 1.5 kW at about 3.6 MHz in the VASIMR experiment, VX-30, using deuterium plasma created by a helicon operating in flowing mode. We have measured ICRF plasma loading up to 2 ohms, consistent with computational predictions made using Oak Ridge National Laboratory's EMIR code. Recent helicon power upgrades (20 kW at 13.56 MHz) have enabled a 5 cm diameter target plasma for ICRF with an ion flux of over 3x10 20 s-1 and a high degree of ionization. This paper summarizes our ICRF results and presents the latest helicon developments in VX-30.

  1. Colliding pulse injection experiments in non-collinear geometryfor controlled laser plasma wakefield acceleration of electrons

    SciTech Connect

    Toth, Carl B.; Esarey, Eric H.; Geddes, Cameron G.R.; Leemans,Wim P.; Nakamura, Kei; Panasenko, Dmitriy; Schroeder, Carl B.; Bruhwiler,D.; Cary, J.R.

    2007-06-25

    An optical injection scheme for a laser-plasma basedaccelerator which employs a non-collinear counter-propagating laser beamto push background electrons in the focusing and acceleration phase viaponderomotive beat with the trailing part of the wakefield driver pulseis discussed. Preliminary experiments were performed using a drive beamof a_0 = 2.6 and colliding beam of a_1 = 0.8 both focused on the middleof a 200 mu m slit jet backed with 20 bar, which provided ~; 260 mu mlong gas plume. The enhancement in the total charge by the collidingpulse was observed with sharp dependence on the delay time of thecolliding beam. Enhancement of the neutron yield was also measured, whichsuggests a generation of electrons above 10 MeV.

  2. Imaging system QA of a medical accelerator, Novalis Tx, for IGRT per TG 142: our 1 year experience.

    PubMed

    Chang, Zheng; Bowsher, James; Cai, Jing; Yoo, Sua; Wang, Zhiheng; Adamson, Justus; Ren, Lei; Yin, Fang-Fang

    2012-01-01

    American Association of Physicists in Medicine (AAPM) task group (TG) 142 has recently published a report to update recommendations of the AAPM TG 40 report and add new recommendations concerning medical accelerators in the era of image-guided radiation therapy (IGRT). The recommendations of AAPM TG 142 on IGRT are timely. In our institute, we established a comprehensive imaging QA program on a medical accelerator based on AAPM TG 142 and implemented it successfully. In this paper, we share our one-year experience and performance evaluation of an OBI capable linear accelerator, Novalis Tx, per TG 142 guidelines. PMID:22766946

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

    PubMed

    Ford, Judith H

    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

  4. Aging, source memory, and the experience of "remembering".

    PubMed

    Kuhlmann, Beatrice G; Boywitt, C Dennis

    2016-07-01

    In a previous study, we found source memory for perceptual features to differentiate between younger but not older adults' reports of recollective ("remember"; R) and "know" (K) experiences. In two experiments with younger (17-30 years) and older (64-81 years) participants, we examined whether memory for meaningful speaker sources would accompany older adults' recollective experience. Indeed, memory for male and female speakers (but not partial memory for gender; Experiment 1) as well as bound memory for speakers and their facial expressions (Experiment 2) distinguished between both younger and older adults' RK reports. Thus, memory for some sources forms a common basis for younger and older adults' retrieval experience. Nonetheless, older adults still showed lower objective source memory and lower subjective source-attribution confidence than younger adults when reporting recollective experiences, suggesting that source memory is less relevant to their retrieval experience than for younger adults. PMID:26653292

  5. Optimization of accelerator target and detector for portal imaging using Monte Carlo simulation and experiment

    NASA Astrophysics Data System (ADS)

    Flampouri, S.; Evans, P. M.; Verhaegen, F.; Nahum, A. E.; Spezi, E.; Partridge, M.

    2002-09-01

    Megavoltage portal images suffer from poor quality compared to those produced with kilovoltage x-rays. Several authors have shown that the image quality can be improved by modifying the linear accelerator to generate more low-energy photons. This work addresses the problem of using Monte Carlo simulation and experiment to optimize the beam and detector combination to maximize image quality for a given patient thickness. A simple model of the whole imaging chain was developed for investigation of the effect of the target parameters on the quality of the image. The optimum targets (6 mm thick aluminium and 1.6 mm copper) were installed in an Elekta SL25 accelerator. The first beam will be referred to as Al6 and the second as Cu1.6. A tissue-equivalent contrast phantom was imaged with the 6 MV standard photon beam and the experimental beams with standard radiotherapy and mammography film/screen systems. The arrangement with a thin Al target/mammography system improved the contrast from 1.4 cm bone in 5 cm water to 19% compared with 2% for the standard arrangement of a thick, high-Z target/radiotherapy verification system. The linac/phantom/detector system was simulated with the BEAM/EGS4 Monte Carlo code. Contrast calculated from the predicted images was in good agreement with the experiment (to within 2.5%). The use of MC techniques to predict images accurately, taking into account the whole imaging system, is a powerful new method for portal imaging system design optimization.

  6. 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

  7. Semantic Development in Spanish-English Bilingual Children: Effects of Age and Language Experience

    ERIC Educational Resources Information Center

    Sheng, Li; Bedore, Lisa M.; Pena, Elizabeth D.; Fiestas, Christine

    2013-01-01

    This study examines semantic development in 60 Spanish-English bilingual children, ages 7 years 3 months to 9 years 11 months, who differed orthogonally in age (younger, older) and language experience (higher English experience [HEE], higher Spanish experience [HSE]). Children produced 3 associations to 12 pairs of translation equivalents. Older…

  8. Systematic Study of Spin Effects at SPASCHARM Experiment at 70-GeV Accelerator in Protvino

    NASA Astrophysics Data System (ADS)

    Mochalov, V. V.; Abramov, V. V.; Bazhanov, N. A.; Borisov, N. S.; Derevschikov, A. A.; Evdokimova, A. S.; Meshchanin, A. P.; Minaev, N. G.; Morozov, D. A.; Nurushev, S. B.; Ryzhikov, S. V.; Semenov, P. A.; Ryazantsev, A. V.; Strikhanov, M. N.; Rykov, V. L.; Usov, Y. A.; Vasiliev, A. N.

    2016-02-01

    A new experiment SPASCHARM for systematic study of polarization phenomena in the inclusive and exclusive hadronic reactions in the energy range of IHEP accelerator U-70 (12-50GeV) is currently under development. The universal experimental setup will detect dozens of various resonances and stable particles produced in collisions of unpolarized beams with the polarized target, and at the next stage, using polarized proton and antiproton beams. At the beginning, the final states consisting of light quarks (u, d, s) will be reconstructed, and later on the charmonium states will be studied. Measurements are planned for a variety of beams: π±,K±,p, antiprotons. Hyperon polarization and spin density matrix elements of the vector mesons will be measured along with the single-spin asymmetry (SSA). The 2π-acceptance in azimuth, which is extremely useful for reduction of systematic errors in measurements of spin observables, will be implemented in the experiment. The solid angle acceptance of the setup, Δθ ≈ 250 mrad vertically and 350 mrad horizontally in the beam fragmentation region, covers a wide range of kinematic variables pT and xF. This provides the opportunity for separating dependences on these two variables which is usually not possible in the setups with a small solid angle acceptance. Unlike some previous polarization experiments, the SPASCHARM will be able to simultaneously accumulate and record data on the both, charged and neutral particle production.

  9. ATTO SECOND ELECTRON BEAMS GENERATION AND CHARACTERIZATION EXPERIMENT AT THE ACCELERATOR TEST FACILITY.

    SciTech Connect

    ZOLOTOREV, M.; ZHOLENTS, A.; WANG, X.J.; BABZIEN, M.; SKARITKA, J.; RAKOWSKY, G.; YAKIMENKO, V.

    2002-02-01

    We are proposing an Atto-second electron beam generation and diagnostics experiment at the Brookhaven Accelerator Test facility (ATF) using 1 {micro}m Inverse Free Electron Laser (IFEL). The proposed experiment will be carried out by an BNL/LBNL collaboration, and it will be installed at the ATF beam line II. The proposed experiment will employ a one-meter long undulator with 1.8 cm period (VISA undulator). The electron beam energy will be 63 MeV with emittance less than 2 mm-mrad and energy spread less than 0.05%. The ATF photocathode injector driving laser will be used for energy modulation by Inverse Free Electron Laser (IFEL). With 10 MW laser peak power, about 2% total energy modulation is expected. The energy modulated electron beam will be further bunched through either a drift space or a three magnet chicane into atto-second electron bunches. The attosecond electron beam bunches will be analyzed using the coherent transition radiation (CTR).

  10. Synergy Between Experiments and Simulations in Laser and Beam-Driven Plasma Acceleration and Light Sources

    NASA Astrophysics Data System (ADS)

    Mori, Warren B.

    2015-11-01

    Computer simulations have been an integral part of plasma physics research since the early 1960s. Initially, they provided the ability to confirm and test linear and nonlinear theories in one-dimension. As simulation capabilities and computational power improved, then simulations were also used to test new ideas and applications of plasmas in multi-dimensions. As progress continued, simulations were also used to model experiments. Today computer simulations of plasmas are ubiquitously used to test new theories, understand complicated nonlinear phenomenon, model the full temporal and spatial scale of experiments, simulate parameters beyond the reach of current experiments, and test the performance of new devices before large capital expenditures are made to build them. In this talk I review the progress in simulations in a particular area of plasma physics: plasma based acceleration (PBA). In PBA a short laser pulse or particle beam propagates through long regions of plasma creating plasma wave wakefields on which electrons or positrons surf to high energies. In some cases the wakefields are highly nonlinear, involve three-dimensional effects, and the trajectories of plasma particles cross making it essential that fully kinetic and three-dimensional models are used. I will show how particle-in-cell (PIC) simulations were initially used to propose the basic idea of PBA in one dimension. I will review some of the dramatic progress in the experimental demonstration of PBA and show how this progress was dramatically helped by a synergy between experiments and full-scale multi-dimensional PIC simulations. This will include a review of how the capability of PIC simulation tools has improved. I will also touch on some recent progress on improvements to PIC simulations of PBA and discuss how these improvements may push the synergy further towards real time steering of experiments and start to end modeling of key components of a future linear collider or XFEL based on PBA

  11. Leukocyte Telomere Length in Young Adults Born Preterm: Support for Accelerated Biological Ageing

    PubMed Central

    Smeets, Carolina C. J.; Codd, Veryan; Samani, Nilesh J.; Hokken-Koelega, Anita C. S.

    2015-01-01

    Background Subjects born preterm have an increased risk for age-associated diseases, such as cardiovascular disease in later life, but the underlying causes are largely unknown. Shorter leukocyte telomere length (LTL), a marker of biological age, is associated with increased risk of cardiovascular disease. Objectives To compare LTL between subjects born preterm and at term and to assess if LTL is associated with other putative cardiovascular risk factors at young adult age. Methods We measured mean LTL in 470 young adults. LTL was measured using a quantitative PCR assay and expressed as T/S ratio. We analyzed the influence of gestational age on LTL and compared LTL between subjects born preterm (n = 186) and at term (n = 284). Additionally, we analyzed the correlation between LTL and potential risk factors of cardiovascular disease. Results Gestational age was positively associated with LTL (r = 0.11, p = 0.02). Subjects born preterm had shorter LTL (mean (SD) T/S ratio = 3.12 (0.44)) than subjects born at term (mean (SD) T/S ratio = 3.25 (0.46)), p = 0.003). The difference remained significant after adjustment for gender and size at birth (p = 0.001). There was no association of LTL with any one of the putative risk factors analyzed. Conclusions Young adults born preterm have shorter LTL than young adults born at term. Although we found no correlation between LTL and risk for CVD at this young adult age, this biological ageing indicator may contribute to CVD and other adult onset diseases at a later age in those born preterm. PMID:26619005

  12. Comparison of clinical explants and accelerated hydrolytic aging to improve biostability assessment of silicone-based polyurethanes.

    PubMed

    Cosgriff-Hernandez, Elizabeth; Tkatchouk, Ekaterina; Touchet, Tyler; Sears, Nick; Kishan, Alysha; Jenney, Christopher; Padsalgikar, Ajay D; Chen, Emily

    2016-07-01

    Although silicone-based polyurethanes have demonstrated increased oxidative stability, there have been conflicting reports of the long-term hydrolytic stability of Optim™ and PurSil(®) 35 based on recent temperature-accelerated hydrolysis studies. The goal of the current study was to identify in vitro-in vivo correlations to determine the relevance of this accelerated in vitro model for predicting clinical outcomes. Temperature-accelerated hydrolytic aging of three commonly used cardiac lead insulation materials, Optim™, Elasthane™ 55D, Elasthane™ 80A, and a related silicone-polyurethane, PurSil(®) 35, was performed. After 1 year at 85°C, similar losses in Mn and Mz were observed for the poly(ether urethanes), but an increase in Mz loss as compared to Mn loss was observed for the silicone-based polyurethanes. A similar trend of increased Mz loss as compared to Mn loss was observed in explanted Optim™ leads after 2-3 years; however, no statistically significant Mn loss was detected between 2-3 and 7-8 years of implantation. Given this preferential loss of high molecular weight chains, it was hypothesized that the observed differences between the polyurethanes were due to allophanate dissociation rather than backbone chain scission. Following full dissociation of the small percentage of allophanates in vivo, the observed molecular weight stability and proven clinical performance of Optim™ was attributed to the well-documented stability of the urethane bond under physiological conditions. This allophanate dissociation reaction is incompatible with the first order mechanism proposed in previous temperature-accelerated hydrolysis studies and may be the reason for the model's inaccurate prediction of significant and progressive molecular weight loss in vivo. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1805-1816, 2016. PMID:26990709

  13. 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

  14. 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

  15. 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.

  16. Active immunization of broiler breeder cockerels against chicken inhibin accelerates puberty and prevents age-induced testicular involution.

    PubMed

    Satterlee, D G; Castille, S A; Fioretti, W C

    2006-06-01

    Injection of quail and breeder hens with a recombinant protein antigen (MBP-cINA521)--a fusion of the bacterical maltose-binding protein (MBP) and a fragment of the alpha-subunit of chicken inhibin (cINA521)--accelerates puberty and enhances lay. Herein, the effects of this immunogen on reproductive responses in broiler breeder males were assessed. Cockerels were subcutaneously injected with 0 (vehicular controls), 1, 3, or 5 mg of MBP-cINA521 at 13 wk of age and with one-half of these dosages (boosters) at 18 wk. Bird subsamples were weighed, blood sampled, and killed at 24, 28, and 39 wk of age to assess age and vaccination effects on BW, testes weight (TWT), TWT relative to BW (RTWT), TWT > or = 20 g (TWT20; theoretical threshold TWT for maximum fertility), and plasma testosterone. Breeder males are sexually developing, reach peak sexual activity, and show age-related reproductive decline at these ages. Because vaccine gonadal effects at 24 wk appeared to be dramatic, the size of the left testis was also scored to see if size differences could be detected by mere visual inspection. Male fighting increasingly reduced sample sizes beyond 24 wk. Because mortality was unrelated to the treatments and to insure meaningful statistical comparisons, MBP-cINA521 data were pooled. Body weight (P < 0.04), testis score (P < 0.02), TWT (P < 0.03), RTWT (P = 0.06), and plasma testosterone (P = 0.08) were elevated in immunogen-treated males at 24 wk of age, and more (P < 0.05) MBP-cINA521-treated birds than controls achieved a TWT20 at this time. These variables did not differ by treatment at 28 wk. However, by 39 wk, treatment effects reemerged as follows: TWT (P < 0.04), RTWT (P = 0.06), and TWT20 (P < 0.01) were increased in vaccinated males who also showed nearly 3-fold higher levels of plasma testosterone. We conclude that immunoneutralization of inhibin accelerates puberty and retards age-related sexual senescence that typically occurs in broiler breeder males. PMID

  17. Fusion-neutron measurements for magnetized liner inertial fusion experiments on the Z accelerator

    DOE PAGESBeta

    Hahn, K. D.; Chandler, G. A.; Ruiz, C. L.; Cooper, G. W.; Gomez, M. R.; Slutz, S.; Sefkow, A. B.; Sinars, D. B.; Hansen, S. B.; Knapp, P. F.; et al

    2016-05-01

    Several magnetized liner inertial fusion (MagLIF) experiments have been conducted on the Z accelerator at Sandia National Laboratories since late 2013. Measurements of the primary DD (2.45 MeV) neutrons for these experiments suggest that the neutron production is thermonuclear. Primary DD yields up to 3e12 with ion temperatures ~2-3 keV have been achieved. Measurements of the secondary DT (14 MeV) neutrons indicate that the fuel is significantly magnetized. Measurements of down-scattered neutrons from the beryllium liner suggest ρRliner ~ 1g/cm2. Neutron bang times, estimated from neutron time-of-flight (nTOF) measurements, coincide with peak x-ray production. Furthermore, plans to improve and expandmore » the Z neutron diagnostic suite include neutron burn-history diagnostics, increased sensitivity and higher precision nTOF detectors, and neutron recoil-based yield and spectral measurements.« less

  18. Beam-wall interaction measurements in LLNL induction accelerator bend experiment

    NASA Astrophysics Data System (ADS)

    Molvik, A. W.; Friedman, A.; Kamin, G. W.; Sangster, T. C.; Eylon, S.; Hopkins, H. S.

    1997-11-01

    Ion-induced desorption coefficients are determined from measurements of pressure rises when an ion beam strikes a surface. These measurements are made after the first bend of 9^circ by deflecting the beam onto the stainless steel beam tube, and within a pill-box where the beam strikes a stainless steel target at an angle that can be varied from 90^circ to ~10^circ. The beam consists of 2 mA of singly-charged potassium ions at 80 keV with pulse lengths of several microsec. Data near 10^circ are relevant to near-term experiments where beam halo could strike the wall at angles of a few degrees. Data near 90^circ are relevant to ions resulting from charge exchange with a reactor driver class beam which has a space potential of the order of 100 kV. These data will aid in assessing the adequacy of the existing vacuum system when the bend experiment is upgraded to a recirculator induction accelerator.

  19. 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.

  20. Proof-Of-Principle Experiment for Laser-Driven Acceleration of Relativistic Electrons in a Semi-Infinite Vacuum

    SciTech Connect

    Plettner, T.; Byer, R.L.; Colby, E.; Cowan, B.; Sears, C.M.S.; Spencer, J.E.; Siemann, R.H.; /SLAC

    2006-03-01

    We recently achieved the first experimental observation of laser-driven particle acceleration of relativistic electrons from a single Gaussian near-infrared laser beam in a semi-infinite vacuum. This article presents an in-depth account of key aspects of the experiment. An analysis of the transverse and longitudinal forces acting on the electron beam is included. A comparison of the observed data to the acceleration viewed as an inverse transition radiation process is presented. This is followed by a detailed description of the components of the experiment and a discussion of future measurements.

  1. High-Current Experiments for Accelerator-Based Neutron Capture Therapy Applications

    SciTech Connect

    Gierga, D.P.; Klinkowstein, R.E.; Hughey, B.H.; Shefer, R.E.; Yanch, J.C.; Blackburn, B.W.

    1999-06-06

    Several accelerator-based neutron capture therapy applications are under development. These applications include boron neutron capture therapy for glioblastoma multiform and boron neutron capture synovectomy (BNCS) for rheumatoid arthritis. These modalities use accelerator-based charged-particle reactions to create a suitable neutron source. Neutrons are produced using a high-current, 2-MV terminal tandem accelerator. For these applications to be feasible, high accelerator beam currents must be routinely achievable. An effort was undertaken to explore the operating regime of the accelerator in the milliampere range. In preparation for high-current operation of the accelerator, computer simulations of charged-particle beam optics were performed to establish high-current operating conditions. Herein we describe high beam current simulations and high beam current operation of the accelerator.

  2. The theory of bipolar disorder as an illness of accelerated aging: implications for clinical care and research.

    PubMed

    Rizzo, Lucas Bortolotto; Costa, Leonardo Gazzi; Mansur, Rodrigo B; Swardfager, Walter; Belangero, Síntia Iole; Grassi-Oliveira, Rodrigo; McIntyre, Roger S; Bauer, Moisés E; Brietzke, Elisa

    2014-05-01

    Bipolar Disorder (BD) has been conceptualized as both a cyclic and a progressive disorder. Mechanisms involved in neuroprogression in BD remain largely unknown although several non-mutually exclusive models have been proposed as explanatory frameworks. In the present paper, we propose that the pathophysiological changes observed in BD (e.g. brain structural alterations, cognitive deficits, oxidative stress imbalance, amyloid metabolism, immunological deregulation, immunosenescence, neurotrophic deficiencies and telomere shortening) converge on a model of accelerated aging (AA). Aging can be understood as a multidimensional process involving physical, neuropsychological, and social changes, which can be highly variable between individuals. Determinants of successful aging (e.g environmental and genetic factors), may also confer differential vulnerability to components of BD pathophysiology and contribute to the clinical presentation of BD. Herein we discuss how the understanding of aging and senescence can contribute to the search for new and promising molecular targets to explain and ameliorate neuroprogression in BD. We also present the strengths and limitations of this concept. PMID:24548785

  3. The physics of sub-critical lattices in accelerator driven hybrid systems: The MUSE experiments in the MASURCA facility

    SciTech Connect

    Chauvin, J. P.; Lebrat, J. F.; Soule, R.; Martini, M.; Jacqmin, R.; Imel, G. R.; Salvatores, M.

    1999-06-10

    Since 1991, the CEA has studied the physics of hybrid systems, involving a sub-critical reactor coupled with an accelerator. These studies have provided information on the potential of hybrid systems to transmute actinides and, long lived fission products. The potential of such a system remains to be proven, specifically in terms of the physical understanding of the different phenomena involved and their modelling, as well as in terms of experimental validation of coupled systems, sub-critical environment/accelerator. This validation must be achieved through mock-up studies of the sub-critical environments coupled to a source of external neutrons. The MUSE-4 mock-up experiment is planed at the MASURCA facility and will use an accelerator coupled to a tritium target. The great step between the generator used in the past and the accelerator will allow to increase the knowledge in hybrid physic and to decrease the experimental biases and the measurement uncertainties.

  4. 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

  5. The Experience of Age-Related Macular Degeneration

    ERIC Educational Resources Information Center

    Wong, Elaine Y. H.; Guymer, Robyn H.; Hassell, Jennifer B.; Keeffe, Jill E.

    2004-01-01

    This qualitative article describes the impact of age-related macular degeneration (ARMD) among 15 participants: how a person makes sense of ARMD, the effect of ARMD on the person's quality of life, the psychological disturbances associated with the limitations of ARMD, and the influence of ARMD on social interactions. Such in-depth appreciation of…

  6. Experiences with physical conditioning programs in middle-aged men

    NASA Technical Reports Server (NTRS)

    Schuster, B.; Stanley, E.

    1969-01-01

    Long term effects of physical exercise and conditioning in the prevention and treatment of coronary heart disease are studied. Some aspects of the problem are outlined and difficulties encountered in a group of middle aged business executives using a carefully prescribed, but non-regimented and loosely supervised conditioning program employing commonly used forms of exercise (bicycling and jogging), are described.

  7. Learning Wellness: How Ageing Australians Experience Health Information Literacy

    ERIC Educational Resources Information Center

    Yates, Christine; Partridge, Helen; Bruce, Christine

    2009-01-01

    Given identified synergies between information use and health status greater understanding is needed about how people use information to learn about their health. This paper presents the findings of preliminary research into health information literacy. Analysis of data from semi-structured interviews revealed six different ways ageing Australians…

  8. 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

  9. 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. PMID:26721440

  10. 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. PMID:25801548

  11. 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. PMID:8196002

  12. 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. PMID:27194408

  13. 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.

  14. 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

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

    PubMed

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

    2015-05-30

    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

  16. Model experiment of cosmic ray acceleration due to an incoherent wakefield induced by an intense laser pulse

    SciTech Connect

    Kuramitsu, Y.; Sakawa, Y.; Takeda, K.; Tampo, M.; Takabe, H.; Nakanii, N.; Kondo, K.; Tsuji, K.; Kimura, K.; Fukumochi, S.; Kashihara, M.; Tanimoto, T.; Nakamura, H.; Ishikura, T.; Kodama, R.; Mima, K.; Tanaka, K. A.; Mori, Y.; Miura, E.; Kitagawa, Y.

    2011-01-15

    The first report on a model experiment of cosmic ray acceleration by using intense laser pulses is presented. Large amplitude light waves are considered to be excited in the upstream regions of relativistic astrophysical shocks and the wakefield acceleration of cosmic rays can take place. By substituting an intense laser pulse for the large amplitude light waves, such shock environments were modeled in a laboratory plasma. A plasma tube, which is created by imploding a hollow polystyrene cylinder, was irradiated by an intense laser pulse. Nonthermal electrons were generated by the wakefield acceleration and the energy distribution functions of the electrons have a power-law component with an index of {approx}2. The maximum attainable energy of the electrons in the experiment is discussed by a simple analytic model. In the incoherent wakefield the maximum energy can be much larger than one in the coherent field due to the momentum space diffusion or the energy diffusion of electrons.

  17. Awkward or Amazing: Gender and Age Trends in First Intercourse Experiences

    ERIC Educational Resources Information Center

    Walsh, Jennifer L.; Ward, L. Monique; Caruthers, Allison; Merriwether, Ann

    2011-01-01

    Although research continues to highlight significant gender differences in first coital experiences, developmental approaches suggest that some of these patterns may be age-related. Therefore, this study investigated both gender and age differences in first intercourse experiences. Open-ended responses regarding reasons for, and descriptions of,…

  18. Kenyan Student-Teacher Counsellors' Creativity and Its Relationship with Their Gender, Age, and Teaching Experience

    ERIC Educational Resources Information Center

    Kinai, Theresia Kavuli

    2013-01-01

    The purpose of the study was: (1) assess creativity of postgraduate student-teacher counselors whose age range was 25-54 years old, and teaching experience of 4-25 years; and (2) to find out whether age, gender, and teaching experience influence creativity. Seventy-two participants (43 females and 29 males) responded to the ICAS (Ibadan Creativity…

  19. Two Channel Dielectric-Lined Rectangular High Transformer Ratio Accelerator Structure Experiment

    SciTech Connect

    Shchelkunov, S. V.; LaPointe, M. A.; Hirshfield, J. L.; Marshall, T. C.; Sotnikov, G.; Gai, Wei; Conde, M.; Power, J.; Mihalcea, D.

    2010-11-04

    Current status of a two-channel cm-scale rectangular dielectric lined wakefield accelerator structure is described. This structure is installed at the Argonne Wakefield Accelerator facility (AWA), and is presently being evaluated. The device has a transformer ratio of {approx}12.5:1. When driven by a {approx}50 nC single drive bunch it is expected to obtain {approx}6 MV/m acceleration gradient. Related issues are discussed.

  20. A scientific and statistical analysis of accelerated aging for pharmaceuticals. Part 1: accuracy of fitting methods.

    PubMed

    Waterman, Kenneth C; Swanson, Jon T; Lippold, Blake L

    2014-10-01

    Three competing mathematical fitting models (a point-by-point estimation method, a linear fit method, and an isoconversion method) of chemical stability (related substance growth) when using high temperature data to predict room temperature shelf-life were employed in a detailed comparison. In each case, complex degradant formation behavior was analyzed by both exponential and linear forms of the Arrhenius equation. A hypothetical reaction was used where a drug (A) degrades to a primary degradant (B), which in turn degrades to a secondary degradation product (C). Calculated data with the fitting models were compared with the projected room-temperature shelf-lives of B and C, using one to four time points (in addition to the origin) for each of three accelerated temperatures. Isoconversion methods were found to provide more accurate estimates of shelf-life at ambient conditions. Of the methods for estimating isoconversion, bracketing the specification limit at each condition produced the best estimates and was considerably more accurate than when extrapolation was required. Good estimates of isoconversion produced similar shelf-life estimates fitting either linear or nonlinear forms of the Arrhenius equation, whereas poor isoconversion estimates favored one method or the other depending on which condition was most in error. PMID:25043838

  1. The ASP at 125: Advancing Science Literacy in an Age of Acceleration

    NASA Astrophysics Data System (ADS)

    Manning, Jim

    2014-01-01

    On February 7, 2014, the Astronomical Society of the Pacific will celebrate its 125th birthday and a century and a quarter of advancing astronomy and astronomy/science education during a period of revolutionary change in our understanding of the universe. In keeping with both the retrospective and forward-looking nature of such milestones, the presenter will: 1) share highlights of the Society’s work in supporting the communication of astronomy research through its professional publications, and creating innovative astronomy education and public outreach projects and networks to advance student, teacher and public understanding of astronomy and science; 2) report on current NASA- and NSF-funded efforts and on plans going forward; 3) and solicit input from the assembled community on how the ASP can best serve its various constituencies and the cause of science education, communication and literacy at a time when both the universe and life on Earth are accelerating at unprecedented rates. Birthdays are for celebrating; come celebrate with us as we rededicate ourselves to a mission of advancing science literacy through astronomy.

  2. Shock experiments and numerical simulations on low energy portable electrically exploding foil accelerators

    NASA Astrophysics Data System (ADS)

    Saxena, A. K.; Kaushik, T. C.; Gupta, Satish C.

    2010-03-01

    Two low energy (1.6 and 8 kJ) portable electrically exploding foil accelerators are developed for moderately high pressure shock studies at small laboratory scale. Projectile velocities up to 4.0 km/s have been measured on Kapton flyers of thickness 125 μm and diameter 8 mm, using an in-house developed Fabry-Pérot velocimeter. An asymmetric tilt of typically few milliradians has been measured in flyers using fiber optic technique. High pressure impact experiments have been carried out on tantalum, and aluminum targets up to pressures of 27 and 18 GPa, respectively. Peak particle velocities at the target-glass interface as measured by Fabry-Pérot velocimeter have been found in good agreement with the reported equation of state data. A one-dimensional hydrodynamic code based on realistic models of equation of state and electrical resistivity has been developed to numerically simulate the flyer velocity profiles. The developed numerical scheme is validated against experimental and simulation data reported in literature on such systems. Numerically computed flyer velocity profiles and final flyer velocities have been found in close agreement with the previously reported experimental results with a significant improvement over reported magnetohydrodynamic simulations. Numerical modeling of low energy systems reported here predicts flyer velocity profiles higher than experimental values, indicating possibility of further improvement to achieve higher shock pressures.

  3. Nike Experiments on Acceleration of Planar Targets Stabilized with a Short Spike Pulse^1

    NASA Astrophysics Data System (ADS)

    Weaver, J. L.; Velikovich, A. L.; Metzler, N.; Aglitskiy, Y.; Oh, J.; Mostovych, A. N.; Gardner, J. H.

    2005-10-01

    Theoretical work has shown that a low energy spike pulse in front of the drive laser pulse can help mitigate the growth of hydrodynamic instabilities in targets for inertial confinement fusion.[1]^ While other experiments [2] used higher spike pulse energies, this study reports the influence of a lower energy spike and longer spike-main pulse delay on the acceleration of planar CH targets. Time evolution of preimposed sinusoidal ripples on the target surface was observed using a monochromatic x-ray imaging system. Delayed onset and/or suppression of mode growth was found for the spike prepulse shots compared to those with a low intensity foot, in good agreement with predictions from FAST2D simulations. The propagation velocity of the decaying shock wave from the spike pulse was measured with VISAR and was also in good agreement with an analytical prediction.[3] [1] Metzler et al., Phys. Plasmas 6, 3283 (1999); 9, 5050 (2002); 10, 1897 (2003);Goncharov et al., Phys. Plasmas 10, 1906 (2003) ;Betti et al., Phys Plamas 12, 042703 (2005) ;[2]Knauer et al., Phys. Plasmas 12, 056306 (2005) ; [3]Velikovich et al., Phys. Plasmas 10, 3270 (2003). ^1Work supported by U. S. Department of Energy

  4. Numerical simulations of recent proton acceleration experiments with sub-100 TW laser systems

    NASA Astrophysics Data System (ADS)

    Sinigardi, Stefano

    2016-09-01

    Recent experiments carried out at the Italian National Research Center, National Optics Institute Department in Pisa, are showing interesting results regarding maximum proton energies achievable with sub-100 TW laser systems. While laser systems are being continuously upgraded in laboratories around the world, at the same time a new trend on stabilizing and making ion acceleration results reproducible is growing in importance. Almost all applications require a beam with fixed performance, so that the energy spectrum and the total charge exhibit moderate shot to shot variations. This result is surely far from being achieved, but many paths are being explored in order to reach it. Some of the reasons for this variability come from fluctuations in laser intensity and focusing, due to optics instability. Other variation sources come from small differences in the target structure. The target structure can vary substantially, when it is impacted by the main pulse, due to the prepulse duration and intensity, the shape of the main pulse and the total energy deposited. In order to qualitatively describe the prepulse effect, we will present a two dimensional parametric scan of its relevant parameters. A single case is also analyzed with a full three dimensional simulation, obtaining reasonable agreement between the numerical and the experimental energy spectrum.

  5. Accelerating phylogenetics computing on the desktop: experiments with executing UPGMA in programmable logic.

    PubMed

    Davis, J P; Akella, S; Waddell, P H

    2004-01-01

    Having greater computational power on the desktop for processing taxa data sets has been a dream of biologists/statisticians involved in phylogenetics data analysis. Many existing algorithms have been highly optimized-one example being Felsenstein's PHYLIP code, written in C, for UPGMA and neighbor joining algorithms. However, the ability to process more than a few tens of taxa in a reasonable amount of time using conventional computers has not yielded a satisfactory speedup in data processing, making it difficult for phylogenetics practitioners to quickly explore data sets-such as might be done from a laptop computer. We discuss the application of custom computing techniques to phylogenetics. In particular, we apply this technology to speed up UPGMA algorithm execution by a factor of a hundred, against that of PHYLIP code running on the same PC. We report on these experiments and discuss how custom computing techniques can be used to not only accelerate phylogenetics algorithm performance on the desktop, but also on larger, high-performance computing engines, thus enabling the high-speed processing of data sets involving thousands of taxa. PMID:17270875

  6. Absolute reactivity calibration of accelerator-driven systems after RACE-T experiments

    SciTech Connect

    Jammes, C. C.; Geslot, B.

    2006-07-01

    The RACE-T experiments that were held in november 2005 in the ENEA-Casaccia research center near Rome allowed us to improve our knowledge of the experimental techniques for absolute reactivity calibration at either startup or shutdown phases of accelerator-driven systems. Various experimental techniques for assessing a subcritical level were inter-compared through three different subcritical configurations SC0, SC2 and SC3, about -0.5, -3 and -6 dollars, respectively. The area-ratio method based of the use of a pulsed neutron source appears as the most performing. When the reactivity estimate is expressed in dollar unit, the uncertainties obtained with the area-ratio method were less than 1% for any subcritical configuration. The sensitivity to measurement location was about slightly more than 1% and always less than 4%. Finally, it is noteworthy that the source jerk technique using a transient caused by the pulsed neutron source shutdown provides results in good agreement with those obtained from the area-ratio technique. (authors)

  7. Ice Target and Gas Target Experiments in the IMPACT Dust Accelerator

    NASA Astrophysics Data System (ADS)

    Munsat, T. L.; Collette, A.; Dee, R.; Gruen, E.; Horanyi, M.; James, D.; Janches, D.; Kempf, S.; Plane, J. M. C.; Shu, A. J.; Simolka, J.; Sternovsky, Z.; Thomas, E.

    2014-12-01

    The dust accelerator facility at the SSERVI Institute for Modeling Plasma, Atmospheres, and Cosmic Dust (IMPACT) is presently implementing two major target upgrades: a cryogenic ice target and a high-pressure gas target. The ice target consists of a LN2 cryogenic system connected to both a water-ice deposition system as well as a movable freezer/holder for a pre-mixed liquid cartridge. Planned experiments include the bombardment of a variety of frozen targets and simulated ice/regolith mixtures, and the assessment of all impact products (solid ejecta, gas, plasma) as well as spectroscopy of both the impact-produced light flashes and the reflected spectra (UV, visible, IR). Such measurements are highly relevant to both physical and chemical surface modification of airless bodies due to micrometeoroid impacts. The gas target consists of a differentially pumped chamber kept at moderate background pressures, such that high-velocity (~10 km/s) micrometeoroids are completely ablated within 10's of cm (i.e. within the measurement chamber). The chamber is configured with segmented electrodes to perform a spatially-resolved measurement of charge production during ablation, and localized light-collection optics enable an assessment of the light production (luminous efficiency). Such studies are critical to the understanding of past and future ground-based measurements of meteor ablation in Earth's atmosphere, which in turn can potentially provide the best estimates of the interplanetary dust particle flux.

  8. 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. PMID:18951667

  9. 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

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

    PubMed

    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

  11. Wizards and scientists: the pharmacologic experience in the Middle Ages.

    PubMed

    Rossi, F; Mangrella, M; Loffreda, A; Lampa, E

    1994-01-01

    During the Dark ages, Greco-Roman science survived in the eastern Roman Empire and the most important advances in pharmacology and pharmacy were made in Byzantium. As the Arab empires spread in the 7th and 8th centuries, they incorporated earlier learning, and the most important contribution of Arabic medical writers was probably the introduction of formularies to aid in the preparation of medicines. In turn, the later spread of Arabic knowledge to the West introduced little-known plants and fostered an interest in collecting and cultivating them, and also introduced the palatable dose forms preferred by the Arabic doctors. In the West, however, the Christian Church taught a doctrine of unquestioning faith, and despite the centers of learning, e.g. at Salerno, most ordinary people depended on the healing power of faith, religious relics and traditional folk medicine. Hydrology was also well developed in the Middle Ages. The formularia that survive describe many indigenous plants, but with few illustrations. Their gathering and preparation is generally guided by magic ceremonies and ritual, and plants often took their properties from their habitat, e.g. the wayside plantain was thought good for tired or wounded feet. Concepts of therapeutic plants were also influenced by alchemy and were linked to related metals and planets. PMID:7847474

  12. The Boeing photocathode accelerator magnetic pulse compression and energy recovery experiment

    SciTech Connect

    Dowell, D.H.; Adamski, J.L.; Hayward, T.D.

    1995-12-31

    An 18 MeV, photocathode accelerator operating at 433 MHz is being commissioned for FEL applications. The accelerator consists of a two-cell RF photocathode imjector followed by four new multicell cavities. The two cell injector has previously been operated at a micropulse repetition frequency of 27 MHz, a micropulse charge of 5 nC and 25% duty factor.

  13. Students' Perceptions of Their Experiences from within Acceleration Programs in Mathematics

    ERIC Educational Resources Information Center

    Rawlins, Peter

    2004-01-01

    This article reports on the findings of a research project examining participant students' points of view on accelerated programs in mathematics from four state secondary schools in New Zealand. The four participant schools in this research offered a variety of different acceleration designs and philosophies and were different in size location,…

  14. "DIANA" - A New, Deep-Underground Accelerator Facility for Astrophysics Experiments

    SciTech Connect

    Leitner, M.; Leitner, D.; Lemut, A.; Vetter, P.; Wiescher, M.

    2009-05-28

    The DIANA project (Dakota Ion Accelerators for Nuclear Astrophysics) is a collaboration between the University of Notre Dame, University of North Carolina, Western Michigan University, and Lawrence Berkeley National Laboratory to build a nuclear astrophysics accelerator facility 1.4 km below ground. DIANA is part of the US proposal DUSEL (Deep Underground Science and Engineering Laboratory) to establish a cross-disciplinary underground laboratory in the former gold mine of Homestake in South Dakota, USA. DIANA would consist of two high-current accelerators, a 30 to 400 kV variable, high-voltage platform, and a second, dynamitron accelerator with a voltage range of 350 kV to 3 MV. As a unique feature, both accelerators are planned to be equipped with either high-current microwave ion sources or multi-charged ECR ion sources producing ions from protons to oxygen. Electrostatic quadrupole transport elements will be incorporated in the dynamitron high voltage column. Compared to current astrophysics facilities, DIANA could increase the available beam densities on target by magnitudes: up to 100 mA on the low energy accelerator and several mA on the high energy accelerator. An integral part of the DIANA project is the development of a high-density super-sonic gas-jet target which can handle these anticipated beam powers. The paper will explain the main components of the DIANA accelerators and their beam transport lines and will discuss related technical challenges.

  15. 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

  16. 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.

  17. 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

  18. Does chronic glycolysis accelerate aging? Could this explain how dietary restriction works?

    PubMed

    Hipkiss, Alan R

    2006-05-01

    The mechanisms by which dietary restriction (DR) suppresses aging are not understood. Suppression of glycolysis by DR could contribute to controlling senescence. Many glycolytic intermediates can glycate proteins and other macromolecules. Methyglyoxal (MG), formed from dihydroxyacetone- and glyceraldehyde-3-phosphates, rapidly glycates proteins, damages mitochondria, and induces a prooxidant state to create a senescent-like condition. Ad libitum-fed and DR animals differ in mitochondrial activity and glycolytic flux rates. Persistent glycolysis in the unrestricted condition would increase the intracellular load of glycating agents (e.g., MG) and increase ROS generation by inactive mitochondria. Occasional glycolysis during DR would decrease MG and reactive oxygen species (ROS) production and could be hormetic, inducing synthesis of glyoxalase-1 and anti-glycating agents (carnosine and polyamines). PMID:16804012

  19. Narcolepsy in pediatric age - Experience of a tertiary pediatric hospital.

    PubMed

    Dias Costa, Filipa; Barreto, Maria Inês; Clemente, Vanda; Vasconcelos, Mónica; Estêvão, Maria Helena; Madureira, Núria

    2014-03-01

    Narcolepsy, a chronic disorder of the sleep-wake cycle of multifactorial etiology, is characterized by excessive daytime sleepiness, often associated with cataplexy, hypnagogic/hypnopompic hallucinations and sleep paralysis. Both early clinical suspicion and therapeutic approach are essential for promotion of cognitive development and social integration of these children. The authors present a descriptive retrospective study of a series of eight children in whom symptoms first started between 6.8 and 10.5 years of age. Diagnostic delay ranged from 4 months to 2 years. One child had H1N1 flu vaccination eight months before the clinical onset. The first multiple sleep latency test was positive in 6 of 8 cases. All cases were treated with methylphenidate, and venlafaxine was associated in 4 of them. In one case the initial therapy was exclusively behavioral. In all cases, symptomatic improvement, better school performance and social integration were achieved after therapeutic adjustment. PMID:26483902

  20. Experiments of interest to nuclear astrophysics using 17F, 18F and 56NI beams from the ATLAS accelerator

    SciTech Connect

    Rehm, K.E.

    1997-12-31

    First experiments with radioactive beams of 17F, 18F and 56Ni have been performed at the superconducting accelerator ATLAS at Argonne National laboratory. The experiments address several questions related to the hot CNO cycle and the breakout into the rp process, in particular the production of 19Ne via the 18F(p,gamma) and of 17F via the 14O(4He,p) reactions. The beams were produced by using either the two-accelerator method (18F, 56Ni) or (for 17F) by bombarding a hydrogen (deuterium) target with 17O or 16O, respectively. Special high-efficiency detection techniques were developed to perform experiments with low beam intensities and sometimes considerable isobar impurities. Planned measurements with other radioactive ion beams will be discussed.

  1. Young Children's Learning of Novel Digital Interfaces: How Technology Experience, Age, and Design Come into Play

    ERIC Educational Resources Information Center

    Gilutz, Shuli

    2009-01-01

    This study looks at the relationship between age, technology experience, and design factors in determining young children's comprehension of novel digital interfaces. In Experiment 1, 35 preschoolers played three games that varied in complexity and familiarity. Parental questionnaires were used to assess children's previous technology experience.…

  2. [Immunity and health: the accelerated aging of immune system in veterans of extra risk divisions].

    PubMed

    Puchkova, E I; Alishev, N V; Drabkin, B A; Shubik, V M

    2011-01-01

    This article presents the data about state of health and immunity in veterans of extra risk divisions. The increased morbidity and immunity infringement in the remote terms after nuclear tests, and also while liquidation of consequences of radiating failures on nuclear submarines are shown. Changes of humoral factors of nonspecific protection, concentration of immunoglobulinums, in blood whey, a sensitization of lymphocytes to respiratory viruses, humoral and cellular autoimmune shifts are registered. Some of the revealed changes (complement, lysozyme, concentration of immunoglobulinums) are a consequence of advanced age and accompanying diseases in the people surveyed, and others (autoimmune shifts, a sensitization to respiratory viruses) can be connected with carrying out of tests of the nuclear weapon. Some of immunological changes are apparently a consequence of joined actions of radiating and not radiating factors. Among the last ones stress plays the essential role. For the characteristic of a state of health in 20-40 years after carrying out nuclear tests and possible radiating influence the estimation of autoimmune changes has a great value. The important role of such changes in morbidity of veterans of extra risk divisions is shown. PMID:22550872

  3. 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

  4. Genotoxic stress accelerates age-associated degenerative changes in intervertebral discs.

    PubMed

    Nasto, Luigi A; Wang, Dong; Robinson, Andria R; Clauson, Cheryl L; Ngo, Kevin; Dong, Qing; Roughley, Peter; Epperly, Michael; Huq, Saiful M; Pola, Enrico; Sowa, Gwendolyn; Robbins, Paul D; Kang, James; Niedernhofer, Laura J; Vo, Nam V

    2013-01-01

    Intervertebral disc degeneration (IDD) is the leading cause of debilitating spinal disorders such as chronic lower back pain. Aging is the greatest risk factor for IDD. Previously, we demonstrated IDD in a murine model of a progeroid syndrome caused by reduced expression of a key DNA repair enzyme. This led us to hypothesize that DNA damage promotes IDD. To test our hypothesis, we chronically exposed adult wild-type (Wt) and DNA repair-deficient Ercc1(-/Δ) mice to the cancer therapeutic agent mechlorethamine (MEC) or ionization radiation (IR) to induce DNA damage and measured the impact on disc structure. Proteoglycan, a major structural matrix constituent of the disc, was reduced 3-5× in the discs of MEC- and IR-exposed animals compared to untreated controls. Expression of the protease ADAMTS4 and aggrecan proteolytic fragments was significantly increased. Additionally, new PG synthesis was reduced 2-3× in MEC- and IR-treated discs compared to untreated controls. Both cellular senescence and apoptosis were increased in discs of treated animals. The effects were more severe in the DNA repair-deficient Ercc1(-/Δ) mice than in Wt littermates. Local irradiation of the vertebra in Wt mice elicited a similar reduction in PG. These data demonstrate that genotoxic stress drives degenerative changes associated with IDD. PMID:23262094

  5. Genotoxic stress accelerates age-associated degenerative changes in intervertebral discs

    PubMed Central

    Nasto, Luigi A.; Wang, Dong; Robinson, Andria R.; Clauson, Cheryl L.; Ngo, Kevin; Dong, Qing; Roughley, Peter; Epperly, Michael; Huq, Saiful M.; Pola, Enrico; Sowa, Gwendolyn; Robbins, Paul D.; Kang, James; Niedernhofer, Laura J.; Vo, Nam V.

    2013-01-01

    Intervertebral disc degeneration (IDD) is the leading cause of debilitating spinal disorders such as chronic lower back pain. Aging is the greatest risk factor for IDD. Previously, we demonstrated IDD in a murine model of a progeroid syndrome caused by reduced expression of a key DNA repair enzyme. This led us to hypothesize that DNA damage promotes IDD. To test our hypothesis, we chronically exposed adult wild-type (Wt) and DNA repair-deficient Ercc1−/Δ mice to the cancer therapeutic agent mechlorethamine (MEC) or ionization radiation (IR) to induce DNA damage and measured the impact on disc structure. Proteoglycan, a major structural matrix constituent of the disc, was reduced 3-5x in the discs of MEC- and IR-exposed animals compared to untreated controls. Expression of the protease ADAMTS4 and aggrecan proteolytic fragments were significantly increased. Additionally, new PG synthesis was reduced 2-3x in MEC- and IR-treated discs compared to untreated controls. Both cellular senescence and apoptosis were increased in discs of treated animals. The effects were more severe in the DNA repair-deficient Ercc1−/Δ mice than in Wt littermates. Local irradiation of the vertebra in Wt mice elicited a similar reduction in PG. These data demonstrate that genotoxic stress drives degenerative changes associated with IDD. PMID:23262094

  6. 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. PMID:27132830

  7. Planned High-gradient Flat-beam-driven Dielectric Wakefield Experiments at the Fermilab’s Advanced Superconducting Test Accelerator

    SciTech Connect

    Lemery, Francois; Mihalcea, Daniel; Piot, Philippe; Zhu, Jun

    2014-07-01

    In beam driven dielectric wakefield acceleration (DWA), high-gradient short-wavelength accelerating fields are generally achieved by employing dielectric-lined waveguides (DLWs)  with small aperture which constraints the beam sizes. In this paper we investigate the possibility of using a low-energy (50-MeV) flat beams to induce high-gradient wakes in a slab-symmetric DLW. We demonstrate via numerical simulations the possibility to produce axial electric field with peak amplitude close to 0.5 GV/m. Our studies are carried out using the Fermilab's Advanced Superconducting Test Accelerator (ASTA) photoinjector beamline. We finally discuss a possible experiment that could be performed in the ASTA photoinjector and eventually at higher energies.  

  8. Low micronutrient intake may accelerate the degenerative diseases of aging through allocation of scarce micronutrients by triage.

    PubMed

    Ames, Bruce N

    2006-11-21

    Inadequate dietary intakes of vitamins and minerals are widespread, most likely due to excessive consumption of energy-rich, micronutrient-poor, refined food. Inadequate intakes may result in chronic metabolic disruption, including mitochondrial decay. Deficiencies in many micronutrients cause DNA damage, such as chromosome breaks, in cultured human cells or in vivo. Some of these deficiencies also cause mitochondrial decay with oxidant leakage and cellular aging and are associated with late onset diseases such as cancer. I propose DNA damage and late onset disease are consequences of a triage allocation response to micronutrient scarcity. Episodic shortages of micronutrients were common during evolution. Natural selection favors short-term survival at the expense of long-term health. I hypothesize that short-term survival was achieved by allocating scarce micronutrients by triage, in part through an adjustment of the binding affinity of proteins for required micronutrients. If this hypothesis is correct, micronutrient deficiencies that trigger the triage response would accelerate cancer, aging, and neural decay but would leave critical metabolic functions, such as ATP production, intact. Evidence that micronutrient malnutrition increases late onset diseases, such as cancer, is discussed. A multivitamin-mineral supplement is one low-cost way to ensure intake of the Recommended Dietary Allowance of micronutrients throughout life. PMID:17101959

  9. Optimization of magnetically accelerated, ultra-high velocity aluminum flyer plates for use in plate impact, shock wave experiments.

    SciTech Connect

    Cochrane, Kyle Robert; Knudson, Marcus D.; Slutz, Stephen A.; Lemke, Raymond William; Davis, J. P.; Harjes, Henry Charles III; Giunta, Anthony Andrew; Bliss, David Emery

    2005-05-01

    The intense magnetic field produced by the 20 MA Z accelerator is used as an impulsive pressure source to accelerate metal flyer plates to high velocity for the purpose of performing plate impact, shock wave experiments. This capability has been significantly enhanced by the recently developed pulse shaping capability of Z, which enables tailoring the rise time to peak current for a specific material and drive pressure to avoid shock formation within the flyer plate during acceleration. Consequently, full advantage can be taken of the available current to achieve the maximum possible magnetic drive pressure. In this way, peak magnetic drive pressures up to 490 GPa have been produced, which shocklessly accelerated 850 {micro}m aluminum (6061-T6) flyer plates to peak velocities of 34 km/s. We discuss magnetohydrodynamic (MHD) simulations that are used to optimize the magnetic pressure for a given flyer load and to determine the shape of the current rise time that precludes shock formation within the flyer during acceleration to peak velocity. In addition, we present results pertaining to plate impact, shock wave experiments in which the aluminum flyer plates were magnetically accelerated across a vacuum gap and impacted z-cut, {alpha}-quartz targets. Accurate measurements of resulting quartz shock velocities are presented and analyzed through high-fidelity MHD simulations enhanced using optimization techniques. Results show that a fraction of the flyer remains at solid density at impact, that the fraction of material at solid density decreases with increasing magnetic pressure, and that the observed abrupt decrease in the quartz shock velocity is well correlated with the melt transition in the aluminum flyer.

  10. Neutrino factory and beta beam: accelerator options for future neutrino experiments

    SciTech Connect

    Zisman, Michael S.

    2012-06-03

    Two accelerator options for producing intense neutrino beams a Neutrino Factory based on stored muon beams and a Beta Beam facility based on stored beams of beta unstable ions are described. Technical challenges for each are described and current R&D efforts aimed at mitigating these challenges are indicated. Progress is being made in the design of both types of facility, each of which would extend the state-of-the-art in accelerator science.

  11. Early operating experience with the Brookhaven National Laboratory radio frequency quadrupole accelerator

    SciTech Connect

    Brown, H.; Clifford, T.; Giordano, S.; Khiari, F.; McKenzie-Wilson, R.; Puglisi, M.; Warner, P.

    1984-05-01

    The Brookhaven National Laboratory polarized H/sup -/ injection program for the AGS utilizes a Radio Frequency Quadrupole (RFQ) for acceleration between the polarized H/sup -/ source and the Alvarez Linac. The RFQ accelerator is now in operation with low beam currents. The results of low and high power rf testing will be reported together with initial results of operation in the polarized H/sup -/ beam line.

  12. Correlates of Root Caries Experience in Middle-Aged and Older Adults within the Northwest PRECEDENT

    PubMed Central

    Chi, Donald L.; Berg, Joel H.; Kim, Amy S.; Scott, JoAnna

    2014-01-01

    STRUCTURED ABSTRACT Background We examined the correlates of root caries experience for middle-aged (ages 45–64 years) and older adults (ages 65+ years) to test the hypothesis that the factors related to root caries are different for middle-aged versus older adults. Methods This observational cross-sectional study focused on adult patients ages 45–97 years recruited from the Northwest PRECEDENT (N=775 adults). The outcome variable was any root caries experience (no/yes). Sociodemographic, intraoral, and behavioral factors were hypothesized as potential root caries correlates. We used Poisson regression models to generate overall and age-stratified prevalence ratios (PR) of root caries and Generalized Estimating Equations to account for practice-level clustering of participants. Results About 20% of adults had any root caries. Dentists’ assessment that the patient was at high risk for any caries was associated with greater prevalence of root caries experience in both middle-aged adults (PR=2.70, 95% CI: 1.63,4.46) and older adults (PR=1.87, 95% CI: 1.19,2.95). The following factors were significantly associated with increased root caries prevalence, but only for middle-aged adults: male sex (P=.02), self-reported dry mouth (P<.0001), exposed roots (P=.03), and increased frequency of eating or drinking between meals (P=.03). No other covariates were related to root caries experience for older adults. Conclusions Within a practice-based research network, the factors associated with root caries experience were different for middle-aged and older adults. Future work should identify relevant root caries correlates for adults ages 65+ years. Clinical Implications Interventions aimed at preventing root caries are likely to be different for middle-aged and older adults. Root caries prevention programs should address the appropriate aged-based risk factors. PMID:23633699

  13. Is age-related decline in lean mass and physical function accelerated by Obstructive Lung Disease or smoking?

    PubMed Central

    van den Borst, Bram; Koster, Annemarie; Yu, Binbing; Gosker, Harry R.; Meibohm, Bernd; Bauer, Douglas C.; Kritchevsky, Stephen B.; Liu, Yongmei; Newman, Anne B.; Harris, Tamara B.; Schols, Annemie M.W.J.

    2012-01-01

    Background and aims Cross-sectional studies suggest that Obstructive Lung Disease (OLD) and smoking affect lean mass and mobility. We aimed to investigate whether OLD and smoking accelerate aging-related decline in lean mass and physical functioning. Methods 260 persons with OLD (FEV1 63±18 %predicted), 157 smoking controls (FEV1 95±16 %predicted), 866 formerly smoking controls (FEV1 100±16 %predicted) and 891 never-smoking controls (FEV1 104±17 %predicted) participating in the Health, Aging and Body Composition (ABC) Study were studied. At baseline, the mean age was 74±3 y and participants reported no functional limitations. Baseline and seven-year longitudinal data were investigated of body composition (by Dual-energy X-ray absorptiometry), muscle strength (by hand and leg dynamometry) and Short Physical Performance Battery (SPPB). Results Compared to never-smoking controls, OLD persons and smoking controls had a significantly lower weight, fat mass, lean mass and bone mineral content (BMC) at baseline (p<0.05). While the loss of weight, fat mass, lean mass and strength was comparable between OLD persons and never-smoking controls, the SPPB declined 0.12 points/yr faster in OLD men (p=0.01) and BMC 4 g/yr faster in OLD women (p=0.02). In smoking controls, only lean mass declined 0.1 kg/yr faster in women (p=0.03) and BMC 8 g/yr faster in men (p=0.02) compared to never-smoking controls. Conclusions Initially well-functioning older adults with mild-to-moderate OLD and smokers without OLD have a comparable compromised baseline profile of body composition and physical functioning, while seven-year longitudinal trajectories are to a large extent comparable to those observed in never-smokers without OLD. This suggests a common insult earlier in life related to smoking. 3 PMID:21724748

  14. Acceleration ground test program to verify GAS payload No. 559 structure/support avionics and experiment structural integrity

    NASA Technical Reports Server (NTRS)

    Cassanto, John M.; Cassanto, Valerie A.

    1988-01-01

    Acceleration ground tests were conducted on the Get Away Special (GAS) payload 559 to verify the structural integrity of the structure/support avionics and two of the planned three flight experiments. The ITA (Integrated Test Area) Standardized Experiment Module (ISEM) structure was modified to accommodate the experiments for payload 559. The ISEM avionics consisted of a heavy duty sliver zinc power supply, three orthogonal-mounted low range microgravity accelerometers, a tri-axis high range accelerometer, a solid state recorder/programmer sequencer, and pressure and temperature sensors. The tests were conducted using the Gravitational Plant Physiology Laboratory Centrifuge of the University City Science Center in Philadelphia, PA. The launch-powered flight steady state acceleration profile of the shuttle was simulated from lift-off through jettison of the External Tank (3.0 g's). Additional tests were conducted at twice the nominal powered flight acceleration levels (6 g's) and an over-test condition of four times the powered flight loads to 12.6 g's. The present test program has demonstrated the value of conducting ground tests to verify GAS payload experiment integrity and operation before flying on the shuttle.

  15. Childhood Parasomnias and Psychotic Experiences at Age 12 Years in a United Kingdom Birth Cohort

    PubMed Central

    Fisher, Helen L.; Lereya, Suzet Tanya; Thompson, Andrew; Lewis, Glyn; Zammit, Stanley; Wolke, Dieter

    2014-01-01

    Study Objectives: To examine associations between specific parasomnias and psychotic experiences in childhood. Design: Birth cohort study. Information on the presence of frequent nightmares in children was obtained prospectively from mothers during multiple assessments conducted when children were aged between 2.5 and 9 y. Children were interviewed at age 12 y about nightmares, night terrors, sleepwalking, and psychotic experiences (delusions, hallucinations, and thought interference) occurring in the previous 6 mo. Setting: Assessments were completed in participants' homes or a University clinic within the UK. Patients or Participants: There were 6,796 children (3,462 girls, 50.9%) who completed the psychotic experiences interview. Measurements and Results: Children who were reported by their mothers as experiencing frequent nightmares between 2.5 and 9 y of age were more likely to report psychotic experiences at age 12 y, regardless of sex, family adversity, emotional or behavioral problems, IQ and potential neurological problems (odds ratio (OR) = 1.16, [95% confidence intervals (CI) = 1.00, 1.35], P = 0.049). Children reporting any of the parasomnias at age 12 y also had higher rates of concurrent psychotic experiences than those without such sleeping problems, when adjusting for all confounders (OR = 3.62 [95% CI = 2.57, 5.11], P < 0.001). Difficulty getting to sleep and night waking were not found to be associated with psychotic experiences at age 12 y when controlling for confounders. Conclusion: Nightmares and night terrors, but not other sleeping problems, in childhood were associated with psychotic experiences at age 12 years. These findings tentatively suggest that arousal and rapid eye movement forms of sleep disorder might be early indicators of susceptibility to psychotic experiences. Citation: Fisher HL; Lereya ST; Thompson A; Lewis G; Zammit S; Wolke D. Childhood parasomnias and psychotic experiences at age 12 years in a United Kingdom birth cohort

  16. Appetite and falls: Old age and lived experiences

    PubMed Central

    Sarvimäki, Anneli

    2012-01-01

    Falling among older adults is a well-known public health problem but the association between falling and appetite is seldom studied although poor nutritional status is accepted as a risk factor for falls. On this background the aim of this study was to understand how older adults, who have fallen several times within a year, related their experiences of appetite as a phenomenon in everyday life. In narrative in-depth interviews, eight women and four men contributed with their stories. Using interpretative phenomenology the thematic analysis resulted in three main themes: appetite for food; appetite for social relations and appetite for influence. Eating was not trivial everyday routine and required self-regimentation. Meals were not an object of desire, but of discipline out of the wish to survive. Feelings, reflections and ambivalence were bound to the lack of appetite on food. The participants were oriented towards the forbidden, the delicious and to everyday food as a strengthener and as medicine. In their dependency on help, home was the framework for establishing social relations as means of social support. As well as family and neighbours, the significant others were persons on whom the participants were dependent. Personal relationships and mutual dependencies may ensure social security in lives characterised by contingency and maintain influence in daily life. Falling is both a dramatic and a trivial incident where life and death could be at stake. From this perspective, connectedness was prominent in all fall stories. The quest for influence and a sense of social connectedness was the incentive to re-enter local community arenas and to express solidarity. In health-care practice multi-factorial fall-prevention should be complemented with a multi-dimensional approach in order to balance the medical approach with humanistic and societal approaches towards fall-prevention. PMID:22389651

  17. Supernova / Acceleration Probe: a Satellite Experiment to Study the Nature of the Dark Energy

    SciTech Connect

    Aldering, G.; Althouse, W.; Amanullah, R.; Annis, J.; Astier, P.; Baltay, C.; Barrelet, E.; Basa, S.; Bebek, C.; Bergstrom, L.; Bernstein, G.; Bester, M.; Bigelow, B.; Blandford, R.; Bohlin, R.; Bonissent, A.; Bower, C.; Brown, M.; Campbell, M.; Carithers, W.; Commins, E.; /LBL, Berkeley /SLAC /Stockholm U. /Fermilab /Paris U., VI-VII /Yale U. /Pennsylvania U. /UC, Berkeley /Michigan U. /Baltimore, Space Telescope Sci. /Marseille, CPPM /Indiana U. /American Astron. Society /Caltech /Case Western Reserve U. /Cambridge U. /Saclay /Lyon, IPN

    2005-08-15

    The Supernova/Acceleration Probe (SNAP) is a proposed space-based experiment designed to study the dark energy and alternative explanations of the acceleration of the Universe's expansion by performing a series of complementary systematics-controlled astrophysical measurements. We here describe a self-consistent reference mission design that can accomplish this goal with the two leading measurement approaches being the Type Ia supernova Hubble diagram and a wide-area weak gravitational lensing survey. This design has been optimized to first order and is now under study for further modification and optimization. A 2-m three-mirror anastigmat wide-field telescope feeds a focal plane consisting of a 0.7 square-degree imager tiled with equal areas of optical CCDs and near infrared sensors, and a high-efficiency low-resolution integral field spectrograph. The instrumentation suite provides simultaneous discovery and light-curve measurements of supernovae and then can target individual objects for detailed spectral characterization. The SNAP mission will discover thousands of Type Ia supernovae out to z = 3 and will obtain high-signal-to-noise calibrated light-curves and spectra for a subset of > 2000 supernovae at redshifts between z = 0.1 and 1.7 in a northern field and in a southern field. A wide-field survey covering one thousand square degrees in both northern and southern fields resolves {approx} 100 galaxies per square arcminute, or a total of more than 300 million galaxies. With the PSF stability afforded by a space observatory, SNAP will provide precise and accurate measurements of gravitational lensing. The high-quality data available in space, combined with the large sample of supernovae, will enable stringent control of systematic uncertainties. The resulting data set will be used to determine the energy density of dark energy and parameters that describe its dynamical behavior. The data also provide a direct test of theoretical models for the dark energy

  18. Supernova/Acceleration Probe: A Satellite Experiment to Study the Nature of the Dark Energy

    SciTech Connect

    Aldering, G.; Althouse, W.; Amanullah, R.; Annis, J.; Astier, P.; Baltay, C.; Barrelet, E.; Basa, E.; Bebek, C.; Bergstrom, L.; Bernstein, G.; Bester, M.; Bigelow, C.; Blandford, R.; Bohlin, R.; Bonissent, A.; Bower, C.; Brown, M.; Campbell, M.; Carithers, W.; Commins, E.; Craig, W.; Day, C.; DeJongh, F.; Deustua, S.; Diehl, T.; Dodelson, S.; Ealet, A.; Ellis, R.; Emmet, W.; Fouchez, D.; Frieman, J.; Fruchter, A.; Gerdes, D.; Gladney, L.; Goldhaber, G.; Goobar, A.; Groom, D.; Heetderks, H.; Hoff, M.; Holland, S.; Huffer, M.; Hui, L.; Huterer, D.; Jain, B.; Jelinsky, P.; Karcher, A.; Kent, S.; Kahn, S.; Kim, A.; Kolbe, W.; Krieger, B.; Kushner, G.; Kuznetsova, N.; Lafever, R.; Lamoureux, J.; Lampton, M.; Le Fevre, O.; Levi, M.; Limon, P.; Lin, H.; Linder, E.; Loken, S.; Lorenzon, W.; Malina, R.; Marriner, J.; Marshall, P.; Massey, R.; Mazure, A.; McKay, T.; McKee, S.; Miquel, R.; Morgan, N.; Mortsell, E.; Mostek, N.; Mufson, S.; Musser, J.; Nugent, P.; Oluseyi, H.; Pain, R.; Palaio, N.; Pankow, D.; Peoples, J.; Perlmutter, S.; Prieto, E.; Rabinowitz, D.; Refregier, A.; Rhodes, J.; Roe, N.; Rusin, D.; Scarpine, V.; Schubnell, M.; Sholl, M.; Samdja, G.; Smith, R.M.; Smoot, G.; Snyder, J.; Spadafora, A.; Stebbine, A.; Stoughton, C.; Szymkowiak, A.; Tarle, G.; Taylor, K.; Tilquin, A.; Tomasch, A.; Tucker, D.; Vincent, D.; von der Lippe, H.; Walder, J-P.; Wang, G.; Wester, W.

    2004-05-12

    The Supernova/Acceleration Probe (SNAP) is a proposed space-based experiment designed to study the dark energy and alternative explanations of the acceleration of the Universes expansion by performing a series of complementary systematics-controlled astrophysical measurements. We here describe a self-consistent reference mission design that can accomplish this goal with the two leading measurement approaches being the Type Ia supernova Hubble diagram and a wide-area weak gravitational lensing survey. This design has been optimized to first order and is now under study for further modification and optimization. A 2-m three-mirror anastigmat wide-field telescope feeds a focal plane consisting of a 0.7 square-degree imager tiled with equal areas of optical CCDs and near infrared sensors, and a high efficiency low-resolution integral field spectrograph. The instrumentation suite provides simultaneous discovery and light-curve measurements of supernovae and then can target individual objects for detailed spectral characterization. The SNAP mission will discover thousands of Type Ia supernovae out to z = 3 and will obtain high-signal-to-noise calibrated light-curves and spectra for a subset of > 2000 supernovae at redshifts between z = 0.1 and 1.7 in a northern field and in a southern field. A wide-field survey covering one thousand square degrees in both northern and southern fields resolves {approx} 100 galaxies per square arcminute, or a total of more than 300 million galaxies. With the PSF stability afforded by a space observatory, SNAP will provide precise and accurate measurements of gravitational lensing. The high-quality data available in space, combined with the large sample of supernovae, will enable stringent control of systematic uncertainties. The resulting data set will be used to determine the energy density of dark energy and parameters that describe its dynamical behavior. The data also provide a direct test of theoretical models for the dark energy

  19. The effects of age and experience on memory for visually presented music.

    PubMed

    Meinz, E J; Salthouse, T A

    1998-01-01

    Increased age is often associated with lower levels of performance in tests of memory for spatial information. The primary question in the current study was whether this relationship could be moderated as a function of one's relevant experience and/or knowledge. Stimulus materials consisted of short (7-11 note), visually presented musical melodies and structurally equivalent nonmusical stimuli. Participants (N = 128) were recruited from a wide range of age and experience levels. Although there were strong main effects of age and experience on memory for music, there was no evidence that the age-related differences in memory for these stimuli were smaller for individuals with moderate to large amounts of experience with music. PMID:9469173

  20. Aging of nuclear station diesel generators: Evaluation of operating and expert experience: Phase 1, Study

    SciTech Connect

    Hoopingarner, K.R.; Vause, J.W.; Dingee, D.A.; Nesbitt, J.F.

    1987-08-01

    Pacific Northwest Laboratory evaluated operational and expert experience pertaining to the aging degradation of diesel generators in nuclear service. The research, sponsored by the US Nuclear Regulatory Commission (NRC), identified and characterized the contribution of aging to emergency diesel generator failures. This report, Volume I, reviews diesel-generator experience to identify the systems and components most subject to aging degradation and isolates the major causes of failure that may affect future operational readiness. Evaluations show that as plants age, the percent of aging-related failures increases and failure modes change. A compilation is presented of recommended corrective actions for the failures identified. This study also includes a review of current, relevant industry programs, research, and standards. Volume II reports the results of an industry-wide workshop held on May 28 and 29, 1986 to discuss the technical issues associated with aging of nuclear service emergency diesel generators.

  1. Adolescents' Definitions of Bullying: The Contribution of Age, Gender, and Experience of Bullying

    ERIC Educational Resources Information Center

    Byrne, Hollie; Dooley, Barbara; Fitzgerald, Amanda; Dolphin, Louise

    2016-01-01

    The aim of the present research was to examine adolescents' definitions of bullying in a nationally representative sample of adolescents in Ireland. Definitions of bullying were examined according to age, gender, and bullying experiences. A sample of 4358 adolescents aged 12-19 years (M = 14.99 years, SD = 1.63) provided their definitions of…

  2. Voices of Transformational Learning: Life Experiences of Women Aged Eighty and above in the United States

    ERIC Educational Resources Information Center

    Morgan, Lorri A.

    2010-01-01

    This qualitative research study examined the lived experiences and stories of dynamic women over 80 years of age. Their contribution to transformational and lifelong learning may offer a blueprint for baby boomers to age successfully. The exploration disclosed common patterns of the individual lives. The interviews revealed that the women were…

  3. Relationship of Age, Marital Status, and Work Experience of Community College Nursing Students to Grades.

    ERIC Educational Resources Information Center

    Frerichs, Marian L.

    To investigate differences in academic success due to age (younger or older than age 23), marital status, and nursing experience, a three-way analysis of variance was performed on the grade point averages of 1,435 female nursing students enrolled in 22 Associate Degree Nursing (ADN) programs in Illinois. The sample, representing over 90 percent of…

  4. Empathetic Responses and Attitudes about Older Adults: How Experience with the Aging Game Measures up

    ERIC Educational Resources Information Center

    Henry, Beverly W.; Ozier, Amy D.; Johnson, Amy

    2011-01-01

    This study aimed to assess the impact of pre-professional education on students' knowledge and attitudes about aging, including the option of a simulated learning activity. Using a mixed design, groups of nursing and nutrition students (n = 127) were randomly assigned to experience the Aging Game. Pre- and posttest observations included measures…

  5. Generation and propagation of an electromagnetic pulse in the Trigger experiment and its possible role in electron acceleration

    NASA Technical Reports Server (NTRS)

    Kelley, M. C.; Kintner, P. M.; Kudeki, E.; Holmgren, G.; Bostrom, R.; Fahleson, U. V.

    1980-01-01

    Instruments onboard the Trigger payload detected a large-amplitude, low-frequency, electric field pulse which was observed with a time delay consistent only with an electromagnetic wave. A model for this perturbation is constructed, and the associated field-aligned current is calculated as a function of altitude. This experiment may simulate the acceleration mechanism which results in the formation of auroral arcs, and possibly even other events in cosmic plasmas.

  6. From experiment to design -- Fault characterization and detection in parallel computer systems using computational accelerators

    NASA Astrophysics Data System (ADS)

    Yim, Keun Soo

    This dissertation summarizes experimental validation and co-design studies conducted to optimize the fault detection capabilities and overheads in hybrid computer systems (e.g., using CPUs and Graphics Processing Units, or GPUs), and consequently to improve the scalability of parallel computer systems using computational accelerators. The experimental validation studies were conducted to help us understand the failure characteristics of CPU-GPU hybrid computer systems under various types of hardware faults. The main characterization targets were faults that are difficult to detect and/or recover from, e.g., faults that cause long latency failures (Ch. 3), faults in dynamically allocated resources (Ch. 4), faults in GPUs (Ch. 5), faults in MPI programs (Ch. 6), and microarchitecture-level faults with specific timing features (Ch. 7). The co-design studies were based on the characterization results. One of the co-designed systems has a set of source-to-source translators that customize and strategically place error detectors in the source code of target GPU programs (Ch. 5). Another co-designed system uses an extension card to learn the normal behavioral and semantic execution patterns of message-passing processes executing on CPUs, and to detect abnormal behaviors of those parallel processes (Ch. 6). The third co-designed system is a co-processor that has a set of new instructions in order to support software-implemented fault detection techniques (Ch. 7). The work described in this dissertation gains more importance because heterogeneous processors have become an essential component of state-of-the-art supercomputers. GPUs were used in three of the five fastest supercomputers that were operating in 2011. Our work included comprehensive fault characterization studies in CPU-GPU hybrid computers. In CPUs, we monitored the target systems for a long period of time after injecting faults (a temporally comprehensive experiment), and injected faults into various types of

  7. Cell inactivation, repair and mutation induction in bacteria after heavy ion exposure: results from experiments at accelerators and in space.

    PubMed

    Horneck, G; Schafer, M; Baltschukat, K; Weisbrod, U; Micke, U; Facius, R; Bucker, H

    1989-01-01

    To understand the mechanisms of accelerated heavy ions on biological matter, the responses of spores of B. subtilis to this structured high LET radiation was investigated applying two different approaches. 1) By the use of the Biostack concept, the inactivation probability as a function of radial distance to single particles' trajectory (i.e. impact parameter) was determined in space experiments as well as at accelerators using low fluences of heavy ions. It was found that spores can survive even a central hit and that the effective range of inactivation extends far beyond impact parameters where inactivation by delta-ray dose would be effective. Concerning the space experiment, the inactivation cross section exceeds those from comparable accelerator experiments by roughly a factor of 20. 2) From fluence effect curves, cross sections for inactivation and mutation induction, and the efficiency of repair processes were determined. They are influenced by the ions characteristics in a complex manner. According to dependence on LET, at least 3 LET ranges can be differentiated: A low LET range (app. < 200 keV/micrometers), where cross sections for inactivation and mutation induction follow a common curve for different ions and where repair processes are effective; an intermediate LET range of the so-called saturation cross section with negligible mutagenic and repair efficiency; and a high LET range (>1000 keV/micrometers) where the biological endpoints are majorly dependent on atomic mass and energy of the ion under consideration. PMID:11537282

  8. Planned High-brightness Channeling Radiation Experiment at Fermilab's Advanced Superconducting Test Accelerator

    SciTech Connect

    Blomberg, Ben; Mihalcea, Daniel; Panuganti, Harsha; Piot, Philippe; Brau, Charles; Choi, Bo; Gabella, William; Ivanov, Borislav; Mendenhall, Marcus; Lynn, Christopher; Sen, Tanaji; Wagner, Wolfgang

    2014-07-01

    In this contribution we describe the technical details and experimental setup of our study aimed at producing high-brightness channeling radiation (CR) at Fermilab’s new user facility the Advanced Superconducting Test Accelerator (ASTA). In the ASTA photoinjector area electrons are accelerated up to 40-MeV and focused to a sub-micron spot on a ~40 micron thick carbon diamond, the electrons channel through the crystal and emit CR up to 80-KeV. Our study utilizes ASTA’s long pulse train capabilities and ability to preserve ultra-low emittance, to produce the desired high average brightness.

  9. Construction, commissioning and operational experience of the Advanced Photon Source (APS) linear accelerator

    SciTech Connect

    White, M.; Arnold, N.; Berg, W.

    1996-10-01

    The Advanced Photon Source linear accelerator system consists of a 200 MeV, 2856 MHz S-Band electron linac and a 2-radiation-thick tungsten target followed by a 450 MeV positron linac. The linac system has operated 24 hours per day for the past year to support accelerator commissioning and beam studies and to provide beam for the user experimental program. It achieves the design goal for positron current of 8 mA and produces electron energies up to 650 MeV without the target in place. The linac is described and its operation and performance are discussed.

  10. Translucent tissue defect in potato (Solanum tuberosum L.) tubers is associated with oxidative stress accompanying an accelerated aging phenotype.

    PubMed

    Zommick, Daniel H; Kumar, G N Mohan; Knowles, Lisa O; Knowles, N Richard

    2013-12-01

    Translucent tissue defect (TTD) is an undesirable postharvest disorder of potato tubers characterized by the development of random pockets of semi-transparent tissue containing high concentrations of reducing sugars. Translucent areas turn dark during frying due to the Maillard reaction. The newly released cultivar, Premier Russet, is highly resistant to low temperature sweetening, but susceptible to TTD. Symptoms appeared as early as 170 days after harvest and worsened with time in storage (4-9 °C, 95 % RH). In addition to higher concentrations of glucose, fructose and sucrose, TTD resulted in lower dry matter, higher specific activities of starch phosphorylase and glc-6-phosphate dehydrogenase, higher protease activity, loss of protein, and increased concentrations of free amino acids (esp. asparagine and glutamine). The mechanism of TTD is unknown; however, the disorder has similarities with the irreversible senescent sweetening that occurs in tubers during long-term storage, where much of the decline in quality is a consequence of progressive increases in oxidative stress with advancing age. The respiration rate of non-TTD 'Premier Russet' tubers was inherently higher (ca. 40 %) than that of 'Russet Burbank' tubers (a non-TTD cultivar). Moreover, translucent tissue from 'Premier Russet' tubers had a 1.9-fold higher respiration rate than the average of non-translucent tissue and tissue from non-TTD tubers. Peroxidation of membrane lipids during TTD development resulted in increased levels of malondialdehyde and likely contributed to a measurable increase in membrane permeability. Superoxide dismutase and catalase activities and the ratio of oxidized to total glutathione were substantially higher in translucent tissue. TTD tubers also contained twofold less ascorbate than non-TTD tubers. TTD appears to be a consequence of oxidative stress associated with accelerated aging of 'Premier Russet' tubers. PMID:24037414

  11. 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.

  12. Bleaching Agent Action on Color Stability, Surface Roughness and Microhardness of Composites Submitted to Accelerated Artificial Aging

    PubMed Central

    Rattacaso, Raphael Mendes Bezerra; da Fonseca Roberti Garcia, Lucas; Aguilar, Fabiano Gamero; Consani, Simonides; de Carvalho Panzeri Pires-de-Souza, Fernanda

    2011-01-01

    Objectives: The purpose of this study was to evaluate the bleaching agent action on color stability, surface roughness and microhardness of composites (Charisma, Filtek Supreme and Heliomolar - A2) submitted to accelerated artificial aging (AAA). Methods: A Teflon matrix (12 x 2 mm) was used to fabricate 18 specimens (n=6) which, after polishing (Sof-Lex), were submitted to initial color reading (ΔE), Knoop microhardness (KHN) (50 g/15 s load) and roughness (Ra) (cut-off 0.25 mm) tests. Afterwards, the samples were submitted to AAA for 384 hours and new color, microhardness and roughness readings were performed. After this, the samples were submitted to daily application (4 weeks) of 16% Carbamide Peroxide (NiteWhite ACP) for 8 hours and kept in artificial saliva for 16 hours. New color, microhardness and roughness readings were made at the end of the cycle, and 15 days after bleaching. Results: Comparison of the ΔE means (2-way ANOVA, Bonferroni, P<.05) indicated clinically unacceptable color alteration for all composites after AAA, but without significant difference. Statistically significant increase in the KHN values after AAA was observed, but without significant alterations 15 days after bleaching. For Ra there was no statistically significant difference after AAA and 15 days after bleaching. Conclusions: The alterations promoted by the bleaching agent and AAA are material dependent. PMID:21494380

  13. 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

  14. 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. PMID:25531070

  15. 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

  16. School-Age Prework Experiences of Young People with a History of Specific Language Impairment

    ERIC Educational Resources Information Center

    Durkin, Kevin; Fraser, Jill; Conti-Ramsden, Gina

    2012-01-01

    Young people with specific language impairment (SLI) are at risk for poorer outcomes with respect to employment in adulthood, yet little is known of how early school-age prework experiences prepare them for the job market. This study examined whether young people with SLI engage in similar types of early work experiences as their typically…

  17. Effects of Age, Gender, College Status, and Computer Experience on Attitudes toward Library Computer Systems (LCS).

    ERIC Educational Resources Information Center

    Koohang, Alex A.

    1986-01-01

    This investigation of the effects of age, gender, college status, and computer experience on students' attitudes toward an online catalog measured student attitudes on three subscales--computer anxiety, computer confidence, and computer liking. Results of analysis of variance showed that computer experience was significantly related to computer…

  18. Simulations of laser-wakefield acceleration with external electron-bunch injection for REGAE experiments at DESY

    SciTech Connect

    Grebenyuk, Julia; Mehrling, Timon; Tsung, Frank S.; Floettman, Klaus; Osterhoff, Jens

    2012-12-21

    We present particle-in-cell simulations for future laser-plasma wakefield experiments with external bunch injection at the REGAE accelerator facility at DESY, Hamburg, Germany. Two effects have been studied in detail: emittance evolution of electron bunches externally injected into a wake, and longitudinal bunch compression inside the wakefield. Results show significant transverse emittance growth during the injection process, if the electron bunch is not matched to its intrinsic betatron motion inside the wakefield. This might introduce the necessity to include beam-matching sections upstream of each plasma-accelerator section with fundamental implications on the design of staged laser wakefield accelerators. When externally injected at the zero-field crossing of the laser-driven wake, the electron bunch may undergo significant compression in longitudinal direction and be accelerated simultaneously due to the gradient in the acting force. The mechanism would allow for production of single high-energy, ultra-short (on the order of one femtosecond) bunches at REGAE. The optimal conditions for maximal bunch compression are discussed in the presented studies.

  19. Ten years' experience conducting the Aging Game workshop: was it worth it?

    PubMed

    Pacala, James T; Boult, Chad; Hepburn, Ken

    2006-01-01

    In the Aging Game, medical students experience simulated physical, sensory, and cognitive deficits that are associated with disability from chronic diseases. Since 1994, the University of Minnesota has presented an innovative version of the Aging Game as part of the curriculum in a required clinical clerkship. The experiences conducting the Aging Game over the past decade were reviewed, focusing on the resources necessary to produce it and on its worth as an educational tool. Because many of the reusable props were obtained free as donations, start-up material costs were calculated at 530 dollars. Personnel necessary for each half-day presentation of the Aging Game included two faculty and a minimum of five nonfaculty serving as facilitators; a staff coordinator was also essential. Quantitative student evaluations (N=673) exhibited mean ratings of 1.41, 1.35, and 1.40 (1=excellent) for overall value, teaching effectiveness, and quality of a postsimulation discussion. Written student comments regarding the strengths of the Aging Game centered on three major themes: mode of learning, especially using role playing and simulating deficits (total of 192 comments); attitudinal change, specifically raising awareness and stimulating reflection on the experiences of disabled older adults (121 comments); and educational value, particularly the Aging Game's capacity for creating a memorable impression (56 comments). Despite consuming significant personnel resources, the Minnesota version of the Aging Game is an effective tool for stimulating long-lasting awareness and understanding of key issues related to aging and geriatrics. PMID:16420212

  20. Accelerating Opportunity: A Portrait of Students and Their Program Experiences from the 2014 Student Survey

    ERIC Educational Resources Information Center

    Spaulding, Shayne; Martin-Caughey, Ananda

    2015-01-01

    This report presents findings from a survey of students enrolled in Accelerating Opportunity (AO) career pathways in spring 2014. AO provides grants to help community colleges create career pathway programs to enroll students with low basic skills into for-credit career and technical education courses to improve educational and employment…

  1. Highly accelerated cardiac MRI using iterative SENSE reconstruction: initial clinical experience.

    PubMed

    Allen, Bradley D; Carr, Maria; Botelho, Marcos P F; Rahsepar, Amir Ali; Markl, Michael; Zenge, Michael O; Schmidt, Michaela; Nadar, Mariappan S; Spottiswoode, Bruce; Collins, Jeremy D; Carr, James C

    2016-06-01

    To evaluate the qualitative and quantitative performance of an accelerated cardiovascular MRI (CMR) protocol that features iterative SENSE reconstruction and spatio-temporal L1-regularization (IS SENSE). Twenty consecutively recruited patients and 9 healthy volunteers were included. 2D steady state free precession cine images including 3-chamber, 4-chamber, and short axis slices were acquired using standard parallel imaging (GRAPPA, acceleration factor = 2), spatio-temporal undersampled TSENSE (acceleration factor = 4), and IS SENSE techniques (acceleration factor = 4). Acquisition times, quantitative cardiac functional parameters, wall motion abnormalities (WMA), and qualitative performance (scale: 1-poor to 5-excellent for overall image quality, noise, and artifact) were compared. Breath-hold times for IS SENSE (3.0 ± 0.6 s) and TSENSE (3.3 ± 0.6) were both reduced relative to GRAPPA (8.4 ± 1.7 s, p < 0.001). No difference in quantitative cardiac function was present between the three techniques (p = 0.89 for ejection fraction). GRAPPA and IS SENSE had similar image quality (4.7 ± 0.4 vs. 4.5 ± 0.6, p = 0.09) while, both techniques were superior to TSENSE (quality: 4.1 ± 0.7, p < 0.001). GRAPPA WMA agreement with IS SENSE was good (κ > 0.60, p < 0.001), while agreement with TSENSE was poor (κ < 0.40, p < 0.001). IS SENSE is a viable clinical CMR acceleration approach to reduce acquisition times while maintaining satisfactory qualitative and quantitative performance. PMID:26894256

  2. Experiments with Orbit-Spin Coupling Accelerations in a Mars General Circulation Model

    NASA Astrophysics Data System (ADS)

    Mischna, M. A.; Shirley, J. H.; Newman, C. E.

    2014-12-01

    We explore the hypothesis that year-to-year differences in the orbital angular momentum of Mars [Shirley, this meeting] can contribute to the interannual variability of the Mars climate. For much of the year, the seasonal cycle of the atmospheric circulation is highly repeatable, being driven by global insolation patterns; however, during southern summer (the 'dust storm season'), the atmosphere is more highly variable from year-to-year. The processes underlying this variability are not yet clear. As a means of addressing this uncertainty, we explore the possibility that the root cause may be extrinsic to the atmospheric system itself. Recent work has uncovered a mechanism for a coupling of Mars' orbital and rotational motions that yields heretofore-unsuspected accelerations on the martian atmosphere. These accelerations, while instantaneously small (on the order of 10-5 ms-2), may cumulatively yield wind velocity changes of several 10s of ms-1 on seasonal timescales. Here, we use the MarsWRF general circulation model to examine the effect of these newly identified coupling term accelerations (CTAs) on Mars' atmospheric circulation. The accelerations vary significantly with time, and exhibit variable phasing with respect to Mars' annual cycle. We have run MarsWRF with the inclusion of the additional accelerations for a range of years from MY -16 (1924) to MY 34 (2018). We find that interannual variability in the model output derives largely from differences in the sign and magnitude of the CTAs, confirming one of the predictions of the physical hypothesis. During certain seasons the overall circulation is strengthened by the CTAs, while at other times the CTAs disappear. Resultant surface wind stresses, which are a function of the near-surface winds, are enhanced during periods when the CTAs attain maximum values. We have begun to explore the relationship between the CTAs and the martian dust cycle through its influence on these surface stresses.

  3. Adverse Childhood Experiences and Adult Risk Factors for Age-Related Disease

    PubMed Central

    Danese, Andrea; Moffitt, Terrie E.; Harrington, HonaLee; Milne, Barry J.; Polanczyk, Guilherme; Pariante, Carmine M.; Poulton, Richie; Caspi, Avshalom

    2013-01-01

    Objective To understand why children exposed to adverse psychosocial experiences are at elevated risk for age-related disease, such as cardiovascular disease, by testing whether adverse childhood experiences predict enduring abnormalities in stress-sensitive biological systems, namely, the nervous, immune, and endocrine/metabolic systems. Design A 32-year prospective longitudinal study of a representative birth cohort. Setting New Zealand. Participants A total of 1037 members of the Dunedin Multidisciplinary Health and Development Study. Main Exposures During their first decade of life, study members were assessed for exposure to 3 adverse psychosocial experiences: socioeconomic disadvantage, maltreatment, and social isolation. Main Outcome Measures At age 32 years, study members were assessed for the presence of 3 age-related-disease risks: major depression, high inflammation levels (high-sensitivity C-reactive protein level >3 mg/L), and the clustering of metabolic risk biomarkers (overweight, high blood pressure, high total cholesterol, low high-density lipoprotein cholesterol, high glycated hemoglobin, and low maximum oxygen consumption levels. Results Children exposed to adverse psychosocial experiences were at elevated risk of depression, high inflammation levels, and clustering of metabolic risk markers. Children who had experienced socioeconomic disadvantage (incidence rate ratio, 1.89; 95% confidence interval, 1.36–2.62), maltreatment (1.81; 1.38–2.38), or social isolation (1.87; 1.38–2.51) had elevated age-related-disease risks in adulthood. The effects of adverse childhood experiences on age-related-disease risks in adulthood were nonredundant, cumulative, and independent of the influence of established developmental and concurrent risk factors. Conclusions Children exposed to adverse psychosocial experiences have enduring emotional, immune, and metabolic abnormalities that contribute to explaining their elevated risk for age-related disease. The

  4. Semantic Development in Spanish-English Bilingual Children: Effects of Age and Language Experience

    PubMed Central

    Sheng, Li; Bedore, Lisa M.; Peña, Elizabeth D.; Fiestas, Christine

    2012-01-01

    This study examines semantic development in 60 Spanish-English bilingual children, ages 7 years 3 months to 9 years 11 months, who differed orthogonally in age (younger, older) and language experience (HEE: higher English experience, HSE: higher Spanish experience). Children produced three associations to 12 pairs of translation equivalents. Older children produced more semantic responses and code-switched more often from Spanish to English than younger children. Within each group, children demonstrated better performance in the more frequently used than the less used language. The HEE children outperformed the HSE children in English and the HSE children outperformed the HEE children in Spanish. These effects of age and language experience are consistent with predictions of the Revised Hierarchical Model of bilingual lexical organization. PMID:23163772

  5. Hosing Instability of the Drive Electron Beam in the E157 Plasma-Wakefield Acceleration Experiment at the Stanford Linear Accelerator

    SciTech Connect

    Blue, Brent Edward; /SLAC /UCLA

    2005-10-10

    In the plasma-wakefield experiment at SLAC, known as E157, an ultra-relativistic electron beam is used to both excite and witness a plasma wave for advanced accelerator applications. If the beam is tilted, then it will undergo transverse oscillations inside of the plasma. These oscillations can grow exponentially via an instability know as the electron hose instability. The linear theory of electron-hose instability in a uniform ion column predicts that for the parameters of the E157 experiment (beam charge, bunch length, and plasma density) a growth of the centroid offset should occur. Analysis of the E157 data has provided four critical results. The first was that the incoming beam did have a tilt. The tilt was much smaller than the radius and was measured to be 5.3 {micro}m/{delta}{sub z} at the entrance of the plasma (IP1.) The second was the beam centroid oscillates in the ion channel at half the frequency of the beam radius (betatron beam oscillations), and these oscillations can be predicted by the envelope equation. Third, up to the maximum operating plasma density of E157 ({approx}2 x 10{sup 14} cm{sup -3}), no growth of the centroid offset was measured. Finally, time-resolved data of the beam shows that up to this density, no significant growth of the tail of the beam (up to 8ps from the centroid) occurred even though the beam had an initial tilt.

  6. 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

  7. Nuclear lamina defects cause ATM-dependent NF-κB activation and link accelerated aging to a systemic inflammatory response

    PubMed Central

    Osorio, Fernando G.; Bárcena, Clea; Soria-Valles, Clara; Ramsay, Andrew J.; de Carlos, Félix; Cobo, Juan; Fueyo, Antonio; Freije, José M.P.; López-Otín, Carlos

    2012-01-01

    Alterations in the architecture and dynamics of the nuclear lamina have a causal role in normal and accelerated aging through both cell-autonomous and systemic mechanisms. However, the precise nature of the molecular cues involved in this process remains incompletely defined. Here we report that the accumulation of prelamin A isoforms at the nuclear lamina triggers an ATM- and NEMO-dependent signaling pathway that leads to NF-κB activation and secretion of high levels of proinflammatory cytokines in two different mouse models of accelerated aging (Zmpste24−/− and LmnaG609G/G609G mice). Causal involvement of NF-κB in accelerated aging was demonstrated by the fact that both genetic and pharmacological inhibition of NF-κB signaling prevents age-associated features in these animal models, significantly extending their longevity. Our findings provide in vivo proof of principle for the feasibility of pharmacological modulation of the NF-κB pathway to slow down the progression of physiological and pathological aging. PMID:23019125

  8. 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.

  9. Cognitive experience and its effect on age-dependent cognitive decline in beagle dogs.

    PubMed

    Milgram, Norton W

    2003-11-01

    Test-sophisticated beagle dogs show marked age sensitivity in a size discrimination learning task, with old and senior dogs performing significantly more poorly than young dogs. By contrast, age differences in learning were not seen in dogs naive with respect to neuropsychological test experience. These results indicate that old animals benefit less from prior cognitive experience than young animals, which is an example of an age-dependent loss in plasticity. This finding also suggests that behaviorally experienced animals are a more useful model of human cognitive aging than behaviorally naïve animals. We also looked at the effect of a program of behavioral enrichment in aged dogs. One year of enrichment did not lead to significant differences, but after 2 years the behaviorally enriched group performed significantly better than the control group. The effect after 2 years indicates that a prolonged program of cognitive enrichment can serve as an effective intervention in aged dogs. These findings demonstrate that cognitive abilities in aged animals can be modified by providing behavioral experience, indicating that cognitive abilities remain moderately plastic, even in very old animals. PMID:14584821

  10. X-Band Photonic Band-Gap Accelerator Structure Breakdown Experiment

    SciTech Connect

    Marsh, Roark A.; Shapiro, Michael A.; Temkin, Richard J.; Dolgashev, Valery A.; Laurent, Lisa L.; Lewandowski, James R.; Yeremian, A.Dian; Tantawi, Sami G.; /SLAC

    2012-06-11

    In order to understand the performance of photonic band-gap (PBG) structures under realistic high gradient, high power, high repetition rate operation, a PBG accelerator structure was designed and tested at X band (11.424 GHz). The structure consisted of a single test cell with matching cells before and after the structure. The design followed principles previously established in testing a series of conventional pillbox structures. The PBG structure was tested at an accelerating gradient of 65 MV/m yielding a breakdown rate of two breakdowns per hour at 60 Hz. An accelerating gradient above 110 MV/m was demonstrated at a higher breakdown rate. Significant pulsed heating occurred on the surface of the inner rods of the PBG structure, with a temperature rise of 85 K estimated when operating in 100 ns pulses at a gradient of 100 MV/m and a surface magnetic field of 890 kA/m. A temperature rise of up to 250 K was estimated for some shots. The iris surfaces, the location of peak electric field, surprisingly had no damage, but the inner rods, the location of the peak magnetic fields and a large temperature rise, had significant damage. Breakdown in accelerator structures is generally understood in terms of electric field effects. These PBG structure results highlight the unexpected role of magnetic fields in breakdown. The hypothesis is presented that the moderate level electric field on the inner rods, about 14 MV/m, is enhanced at small tips and projections caused by pulsed heating, leading to breakdown. Future PBG structures should be built to minimize pulsed surface heating and temperature rise.

  11. Neutron dosimetry in linear electron accelerator during radiotherapy treatment: simulation and experiment

    NASA Astrophysics Data System (ADS)

    Manfredotti, Claudio; Nastasi, U.; Ongaro, C.; Stasi, E.; Zanini, Alessandro

    1995-03-01

    In the electron linear accelerators used for radiotherapy by high energy electrons or gamma rays, there is a non negligible production of neutrons by photodisintegration or electrodisintegration reactions on the high Z components of the head machine (target, flattening filter, collimators). At the Experimental Physics Department of Torino University, Torino, Italy an experimental and theoretical evaluation has been performed on the undesired neutron production in the MD Class Mevatron Siemens accelerator used at the Radiotherapy Department of S. Giovanni Battista A.S. Hospital for cancer therapy by a 15 MV gamma ray beam. A simulation of the total process has been carried out, using EGS4 MonteCarlo computer code for the evaluation of photoneutron spectra and MCNP code for the neutron transport in the patient's body. The geometrical description both of the accelerator head in EGS4 and of the anthropomorphous phantom in MCNP have been highly optimized. Experimental measurements have been carried out by bubble detectors BD 100R appropriately allocated inside a new phantom in polyetylene and plexiglass, especially designed for this purpose.

  12. To cut or not to cut: cosmetic surgery usage and women's age-related experiences.

    PubMed

    Eriksen, Shelley J

    2012-01-01

    Part of the developmental trajectory of middle and late life presumes the adjustment to physical aging, an adjustment that is complicated for women for whom the prioritization of beauty is central to their social value in Western societies. A 60-item written questionnaire was distributed to a volunteer community sample of 202 women ages 19-86. From these data, this study tested whether women's cosmetic surgery usage would act as a protective factor in age-related experiences related to body image, self-esteem, and aging attitudes. Cosmetic surgery recipients evidenced less body satisfaction, and more appearance investment with age increases while only non-recipients showed improvements in self-esteem ratings with advancing age. Both recipients and non-recipients showed declines in body care with age, a greater felt discrepancy between actual and perceived age, and less aging anxiety--but non-recipients more so than recipients. Thus, despite having undertaken action to improve their appearance through surgical means at some point in their adult lives, cosmetic surgery recipients did not inevitably feel younger than their years, or better about themselves, compared to those who have not pursued surgery. Study limitations and implications are outlined, and given that cosmetic surgery may become normative practice in future cohorts of aging adults, it concludes with a call for nationally-representative studies using matched-control group research designs typical of public health inquiry more generally. PMID:22696841

  13. Conceptual design of a 1013 -W pulsed-power accelerator for megajoule-class dynamic-material-physics experiments

    NASA Astrophysics Data System (ADS)

    Stygar, W. A.; Reisman, D. B.; Stoltzfus, B. S.; Austin, K. N.; Ao, T.; Benage, J. F.; Breden, E. W.; Cooper, R. A.; Cuneo, M. E.; Davis, J.-P.; Ennis, J. B.; Gard, P. D.; Greiser, G. W.; Gruner, F. R.; Haill, T. A.; Hutsel, B. T.; Jones, P. A.; LeChien, K. R.; Leckbee, J. J.; Lewis, S. A.; Lucero, D. J.; McKee, G. R.; Moore, J. K.; Mulville, T. D.; Muron, D. J.; Root, S.; Savage, M. E.; Sceiford, M. E.; Spielman, R. B.; Waisman, E. M.; Wisher, M. L.

    2016-07-01

    We have developed a conceptual design of a next-generation pulsed-power accelerator that is optimized for megajoule-class dynamic-material-physics experiments. Sufficient electrical energy is delivered by the accelerator to a physics load to achieve—within centimeter-scale samples—material pressures as high as 1 TPa. The accelerator design is based on an architecture that is founded on three concepts: single-stage electrical-pulse compression, impedance matching, and transit-time-isolated drive circuits. The prime power source of the accelerator consists of 600 independent impedance-matched Marx generators. Each Marx comprises eight 5.8-GW bricks connected electrically in series, and generates a 100-ns 46-GW electrical-power pulse. A 450-ns-long water-insulated coaxial-transmission-line impedance transformer transports the power generated by each Marx to a system of twelve 2.5-m-radius water-insulated conical transmission lines. The conical lines are connected electrically in parallel at a 66-cm radius by a water-insulated 45-post sextuple-post-hole convolute. The convolute sums the electrical currents at the outputs of the conical lines, and delivers the combined current to a single solid-dielectric-insulated radial transmission line. The radial line in turn transmits the combined current to the load. Since much of the accelerator is water insulated, we refer to it as Neptune. Neptune is 40 m in diameter, stores 4.8 MJ of electrical energy in its Marx capacitors, and generates 28 TW of peak electrical power. Since the Marxes are transit-time isolated from each other for 900 ns, they can be triggered at different times to construct-over an interval as long as 1 μ s -the specific load-current time history required for a given experiment. Neptune delivers 1 MJ and 20 MA in a 380-ns current pulse to an 18 -m Ω load; hence Neptune is a megajoule-class 20-MA arbitrary waveform generator. Neptune will allow the international scientific community to conduct dynamic

  14. 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

  15. 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

  16. Progress on plasma accelerators

    SciTech Connect

    Chen, P.

    1986-05-01

    Several plasma accelerator concepts are reviewed, with emphasis on the Plasma Beat Wave Accelerator (PBWA) and the Plasma Wake Field Accelerator (PWFA). Various accelerator physics issues regarding these schemes are discussed, and numerical examples on laboratory scale experiments are given. The efficiency of plasma accelerators is then revealed with suggestions on improvements. Sources that cause emittance growth are discussed briefly.

  17. Conceptual designs of two petawatt-class pulsed-power accelerators for high-energy-density-physics experiments

    NASA Astrophysics Data System (ADS)

    Stygar, W. A.; Awe, T. J.; Bailey, J. E.; Bennett, N. L.; Breden, E. W.; Campbell, E. M.; Clark, R. E.; Cooper, R. A.; Cuneo, M. E.; Ennis, J. B.; Fehl, D. L.; Genoni, T. C.; Gomez, M. R.; Greiser, G. W.; Gruner, F. R.; Herrmann, M. C.; Hutsel, B. T.; Jennings, C. A.; Jobe, D. O.; Jones, B. M.; Jones, M. C.; Jones, P. A.; Knapp, P. F.; Lash, J. S.; LeChien, K. R.; Leckbee, J. J.; Leeper, R. J.; Lewis, S. A.; Long, F. W.; Lucero, D. J.; Madrid, E. A.; Martin, M. R.; Matzen, M. K.; Mazarakis, M. G.; McBride, R. D.; McKee, G. R.; Miller, C. L.; Moore, J. K.; Mostrom, C. B.; Mulville, T. D.; Peterson, K. J.; Porter, J. L.; Reisman, D. B.; Rochau, G. A.; Rochau, G. E.; Rose, D. V.; Rovang, D. C.; Savage, M. E.; Sceiford, M. E.; Schmit, P. F.; Schneider, R. F.; Schwarz, J.; Sefkow, A. B.; Sinars, D. B.; Slutz, S. A.; Spielman, R. B.; Stoltzfus, B. S.; Thoma, C.; Vesey, R. A.; Wakeland, P. E.; Welch, D. R.; Wisher, M. L.; Woodworth, J. R.

    2015-11-01

    suggest Z 300 will deliver 4.3 MJ to the liner, and achieve a yield on the order of 18 MJ. Z 800 is 52 m in diameter and stores 130 MJ. This accelerator generates 890 TW at the output of its LTD system, and delivers 65 MA in 113 ns to a MagLIF target. The peak electrical power at the MagLIF liner is 2500 TW. The principal goal of Z 800 is to achieve high-yield thermonuclear fusion; i.e., a yield that exceeds the energy initially stored by the accelerator's capacitors. 2D MHD simulations suggest Z 800 will deliver 8.0 MJ to the liner, and achieve a yield on the order of 440 MJ. Z 300 and Z 800, or variations of these accelerators, will allow the international high-energy-density-physics community to conduct advanced inertial-confinement-fusion, radiation-physics, material-physics, and laboratory-astrophysics experiments over heretofore-inaccessible parameter regimes.

  18. Reactor physics studies for the Advanced Fuel Cycle Initiative (AFCI) Reactor-Accelerator Coupling Experiments (RACE) Project

    NASA Astrophysics Data System (ADS)

    Stankovskiy, Evgeny Yuryevich

    In the recently completed RACE Project of the AFCI, accelerator-driven subcritical systems (ADS) experiments were conducted to develop technology of coupling accelerators to nuclear reactors. In these experiments electron accelerators induced photon-neutron reactions in heavy-metal targets to initiate fission reactions in ADS. Although the Idaho State University (ISU) RACE ADS was constructed only to develop measurement techniques for advanced experiments, many reactor kinetics experiments were conducted there. In the research reported in this dissertation, a method was developed to calculate kinetics parameters for measurement and calculation of the reactivity of ADS, a safety parameter that is necessary for control and monitoring of power production. Reactivity is measured in units of fraction of delayed versus prompt neutron from fission, a quantity that cannot be directly measured in far-subcritical reactors such as the ISU RACE configuration. A new technique is reported herein to calculate it accurately and to predict kinetic behavior of a far-subcritical ADS. Experiments conducted at ISU are first described and experimental data are presented before development of the kinetic theory used in the new computational method. Because of the complexity of the ISU ADS, the Monte-Carlo method as applied in the MCNP code is most suitable for modeling reactor kinetics. However, the standard method of calculating the delayed neutron fraction produces inaccurate values. A new method was developed and used herein to evaluate actual experiments. An advantage of this method is that its efficiency is independent of the fission yield of delayed neutrons, which makes it suitable for fuel with a minor actinide component (e.g. transmutation fuels). The implementation of this method is based on a correlated sampling technique which allows the accurate evaluation of delayed and prompt neutrons. The validity of the obtained results is indicated by good agreement between experimental

  19. Musical experience and the aging auditory system: implications for cognitive abilities and hearing speech in noise.

    PubMed

    Parbery-Clark, Alexandra; Strait, Dana L; Anderson, Samira; Hittner, Emily; Kraus, Nina

    2011-01-01

    Much of our daily communication occurs in the presence of background noise, compromising our ability to hear. While understanding speech in noise is a challenge for everyone, it becomes increasingly difficult as we age. Although aging is generally accompanied by hearing loss, this perceptual decline cannot fully account for the difficulties experienced by older adults for hearing in noise. Decreased cognitive skills concurrent with reduced perceptual acuity are thought to contribute to the difficulty older adults experience understanding speech in noise. Given that musical experience positively impacts speech perception in noise in young adults (ages 18-30), we asked whether musical experience benefits an older cohort of musicians (ages 45-65), potentially offsetting the age-related decline in speech-in-noise perceptual abilities and associated cognitive function (i.e., working memory). Consistent with performance in young adults, older musicians demonstrated enhanced speech-in-noise perception relative to nonmusicians along with greater auditory, but not visual, working memory capacity. By demonstrating that speech-in-noise perception and related cognitive function are enhanced in older musicians, our results imply that musical training may reduce the impact of age-related auditory decline. PMID:21589653

  20. Musical Experience and the Aging Auditory System: Implications for Cognitive Abilities and Hearing Speech in Noise

    PubMed Central

    Parbery-Clark, Alexandra; Strait, Dana L.; Anderson, Samira; Hittner, Emily; Kraus, Nina

    2011-01-01

    Much of our daily communication occurs in the presence of background noise, compromising our ability to hear. While understanding speech in noise is a challenge for everyone, it becomes increasingly difficult as we age. Although aging is generally accompanied by hearing loss, this perceptual decline cannot fully account for the difficulties experienced by older adults for hearing in noise. Decreased cognitive skills concurrent with reduced perceptual acuity are thought to contribute to the difficulty older adults experience understanding speech in noise. Given that musical experience positively impacts speech perception in noise in young adults (ages 18–30), we asked whether musical experience benefits an older cohort of musicians (ages 45–65), potentially offsetting the age-related decline in speech-in-noise perceptual abilities and associated cognitive function (i.e., working memory). Consistent with performance in young adults, older musicians demonstrated enhanced speech-in-noise perception relative to nonmusicians along with greater auditory, but not visual, working memory capacity. By demonstrating that speech-in-noise perception and related cognitive function are enhanced in older musicians, our results imply that musical training may reduce the impact of age-related auditory decline. PMID:21589653

  1. POLAR 5 - An electron accelerator experiment within an aurora. III - Evidence for significant spacecraft charging by an electron accelerator at ionospheric altitudes

    NASA Technical Reports Server (NTRS)

    Jacobsen, T. A.; Maynard, N. C.

    1980-01-01

    The POLAR 5 rocket experiment carried an electron accelerator on a 'daughter' payload which injected a 0.1 A beam of 10 keV electrons in a pulsed mode every 410 ms. With spin and precession, injections were made over a wide range of pitch angles. Measurements from a double probe electric field instrument and from particle detectors on the 'mother' payload and from a crude RPA on the 'daughter' payload are interpreted to indicate that the 'daughter' charges to a potential between several hundred volts and 1 kV. The neutralizing return current to the 'daughter' is shown to be asymmetrically distributed with the majority being collected from the direction of the beam. The additional electrons necessary to neutralize the daughter are thought to be produced and heated through beam-plasma interactions postulated by Maehlum et al. (1980) and Grandal et al. (1980) to explain the particle and optical measurements. Significant electric fields emanating from the charged 'daughter' and the beam are seen at distances exceeding 100 m at the 'mother' payload.

  2. Polar 5 - An electron accelerator experiment within an aurora. I - Instrumentation and geophysical conditions

    NASA Technical Reports Server (NTRS)

    Maehlum, B. N.; Grandal, B.; Jacobsen, T. A.; Maseide, K.; Egeland, A.; Holtet, J.; Soraas, F.; Aarsnes, K.; Stadsnes, J.; Maynard, N. C.

    1980-01-01

    A mother-daughter rocket was launched over two auroral structures, which included a 10 keV electron accelerator and a series of diagnostic instruments for monitoring optical and wave effects generated through beam-atmospheric interactions and production of secondary electrons. The instrumentation, the ground and rocket background measurements obtained, and some of the beam effects on various geophysical parameters are presented. Attention is given to the rocket geometry, capacitance probe, particle counters, photometers, and the bremsstrahlung X-ray detector. Observations on the plasma environment, auroral particle precipitation, d.c. electric field, optical emissions, and auroral background HF and VLF emissions are also discussed.

  3. Aging With Schizophrenia: A Lifelong Experience of Multidimensional Losses and Suffering.

    PubMed

    Avieli, Hila; Mushkin, Peli; Araten-Bergman, Tal; Band-Winterstein, Tova

    2016-04-01

    The aim of this study was to explore the subjective experience of suffering in aging individuals with schizophrenia. Qualitative interviews were conducted with 18 participants aged 60-69. Phenomenological content analysis was performed. Nine dimensions of suffering emerged: social rejection; familial rejection; the symptoms of schizophrenia; hospitalisation; the side effects of medication; loss of employment potential; loss of independent accommodation; loss of social life, and loss of hope to be a partner and a parent. The suffering of aging people with schizophrenia is cumulative and ongoing and thus evokes issues such as existential loneliness and feelings of homelessness. PMID:26992876

  4. Aging of nuclear station diesel generators: Evaluation of operating and expert experience: Workshop

    SciTech Connect

    Hoopingarner, K.R.; Vause, J.W.

    1987-08-01

    Pacific Northwest Laboratory (PNL) evaluated operational and expert experience pertaining to the aging degradation of diesel generators in nuclear service. The research, sponsored by the US Nuclear Regulatory Commission (NRC), identified and characterized the contribution of aging to emergency diesel generator failures. This report, Volume II, reports the results of an industry-wide workshop held on May 28 and 29, 1986, to discuss the technical issues associated with aging of nuclear service emergency diesel generators. The technical issues discussed most extensively were: man/machine interfaces, component interfaces, thermal gradients of startup and cooldown and the need for an accurate industry database for trend analysis of the diesel generator system.

  5. Accelerated Helium and Hydrogen Production in Fe-54 Doped Alloys - Measurements and Calculations for the FIST Experiment

    SciTech Connect

    Greenwood, Lawrence R.; Oliver, Brian M.; Ohnuki, S.; Shiba, K.; Kohno, Y.; Kohyama, A.; Robertson, J. P.; Meadows, J. W.; Gelles, David S.

    2000-09-01

    Helium and hydrogen measurements for F-82H alloys enriched up to 96% in 54Fe demonstrate accelerated gas production due to differences in the isotopic cross sections. The samples were irradiated in the JP-17 and JP-22 experiments in HFIR. Results are compared to calculations using isotopic helium production cross sections from ENDF/B-VI or the computer code, GNASH, for the radioactive isotope 55Fe. Helium measurements demonstrated an accelerated helium (appm)/dpa ratio of 2.3 after a 1.25-year irradiation, an increase of a factor of 4.3 over natural iron, due to higher helium production cross sections for 54Fe and 55Fe. Alloys doped with 55Fe could achieve helium/dpa ratios up to about 20, well above the fusion reactor ratio of 10. Calculations predict that hydrogen production is accelerated by about a factor of 13 over natural iron. However, measurements show that most of this hydrogen is not retained in the samples.

  6. Does early establishment of favorable oral health behavior influence caries experience at age 5 years?

    PubMed Central

    Wigen, Tove I.; Wang, Nina J.

    2015-01-01

    Objective The purpose was to study associations between tooth brushing frequency, use of fluoride lozenges and consumption of sugary drinks at 1.5 year of age and having caries experience at 5 years of age. Methods This study was based on data from the Norwegian Mother and Child Cohort Study conducted by the Norwegian Institute of Public Health and by the Public Dental Services. A total of 1095 children were followed from pregnancy to the age of 5 years. Questionnaires regarding oral health behavior were completed by the parents at 1.5 and 5 years of age. Clinical and radiographic examination of the children was performed at the age of 5 years. Results In multiple logistic regression, having caries experience at 5 years of age was associated with; at 1.5 year of age having the teeth brushed less than twice daily (OR 2.1, CI 1.3–3.6) and being offered sugary drinks at least once a week (OR 1.8, CI 1.1–2.9) when controlled for family characteristics and oral health behavior at 5 years of age. Conclusions Tooth brushing frequency and consumption of sugary drinks in early childhood were related to caries development during preschool age independent of family characteristics and oral health behavior at 5 years of age. The results indicate that early established habits regarding tooth brushing and consumption of sugary drinks have long term effects on caries development. Parents encountering difficulties in establishing favorable oral health behavior in children’s first years of life should receive special attention from health personnel. PMID:25385683

  7. Accelerators for critical experiments involving single-particle upset in solid-state microcircuits

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.

    1985-01-01

    Charged-particle interactions in microelectronic circuit chips (integrated circuits) present a particularly insidious problem for solid-state electronic systems due to the generation of soft errors or single-particle event upset (SEU) by either cosmic rays or other radiation sources. Particle accelerators are used to provide both light and heavy ions in order to assess the propensity of integrated circuit chips for SEU. Critical aspects of this assessment involve the ability to analytically model SEU for the prediction of error rates in known radiation environments. In order to accurately model SEU, the measurement and prediction of energy deposition in the form of an electron-hole plasma generated along an ion track is of paramount importance. This requires the use of accelerators which allow for ease in both energy control (change of energy) and change of ion species. This and other aspects of ion-beam control and diagnostics (e.g., uniformity and flux) are of critical concern for the experimental verification of theoretical SEU models.

  8. Summary of recent experiments on focusing of target-normal-sheath-accelerated proton beam with a stack of conducting foils

    SciTech Connect

    Ni, P. A.; Alexander, N.; Barnard, J. J.; Lund, S. M.

    2014-05-15

    We present a summary of recent experiments on focusing of laser target-normal-sheath-accelerated (TNSA) proton beam with a stack of thin conducting foils. The experiments were performed using the Phelix laser (GSI-Darmstadt) and the Titan laser, Lawrence Livermore National Laboratory. The phenomena consistent with self-collimation (or weak self-focusing) of TNSA protons were experimentally observed for the first time at the Phelix laser user facility, in a specially engineered structure ('lens') consisting of a stack of 300 thin aluminum foils separated by 50 μm vacuum gaps. Follow up experiments using the Titan laser obtained results consistent with the collimation/focusing observed in the initial experiments using the Phelix. The Titan experiments employed improved, 25 μm- and 50 μm-gap targets and the new fine mesh diagnostic. All the experiments were carried out in a “passive environment,” i.e., no external fields were applied, and no neutralization plasma or injection of secondary charged particles was imposed. A plausible interpretation of the observed phenomena is that the combination of magnetic self-pinch forces generated by the beam current together with the simultaneous reduction of the repulsive electrostatic forces due to the conducting foils inhibits radial expansion of the beam.

  9. Simultaneous modulated accelerated radiation therapy in the treatment of nasopharyngeal cancer: A local center's experience

    SciTech Connect

    Wu Shixiu . E-mail: wushixiu@medmail.com.cn; Xie Congying; Jin Xiance; Zhang Ping

    2006-11-15

    Purpose: To evaluate the feasibility, toxicity, and clinical efficacy of simultaneous modulated accelerated radiation therapy boost technique for nasopharyngeal carcinoma. Method and Materials: Seventy-five patients with nasopharyngeal carcinoma were treated with simultaneous modulated accelerated radiation therapy boost technique. Daily fraction of 2.5 Gy and 2.0 Gy were prescribed to the gross tumor volume (GTV) and clinical tumor volume (CTV) to a total dose of 70 Gy and 56 Gy, respectively, in 38 days. In 24 of these patients, GTV was boosted to 80 Gy. Quantitative {sup 99m}Tc-pertechnetate salivary scintigraphy was performed by assessing excretion uptake and excretion index of parotid glands. Results: In dosimetry, the mean doses delivered to the GTV, CTV1, and CTV2 were 68.1 Gy, 58.7 Gy, and 54.3 Gy, respectively. An average of 1% of the GTV and 3% of the CTV received less than 90% and 95% of the prescribed dose, respectively, whereas the mean doses delivered to the organ at risk were kept below tolerance limits. The mean doses to the ipsilateral and contralateral parotids were 31.1 Gy and 21.9 Gy, respectively. {sup 99m}Tc-pertechnetate salivary scintigraphy showed excretion index and uptake index decreased by 44.6% and 28.3%, respectively, in ipsilateral parotid (p < 0.05), whereas no significant decline in contralateral parotid was observed. Acute toxicities were well tolerated, except for the relatively high incidence of severe mucositis. No Grade 4 side effect occurred. With a median follow-up of 23.8 months (range, 10-39 months), the 2-year local progression-free, local-regional progression-free, and distant metastasis-free survival were 97.26%, 87.21%, and 82.03%, respectively. The 2-year overall survival was 86.81%. Conclusions: Simultaneous modulated accelerated radiation therapy yielded superior dose distribution over conventional radiotherapy in nasopharyngeal carcinoma and could be delivered with acceptable toxicity and risky organ sparing. Dose

  10. How Do You Know You're Old? Gender Differences in Cues Triggering the Experience of Personal Aging

    ERIC Educational Resources Information Center

    Panek, Paul E.; Hayslip, Bert, Jr.; Pruett, Jessica H.

    2014-01-01

    In order to evaluate the gender differences on the experience of aging, 142 individuals 50 years of age and older completed an interview regarding experiences with another individual conveying the message that they were "old." Interviewees were asked about the type of situation, the age and gender of the response person, and the…

  11. [Emotional experience and regulation across the adult lifespan: comparative analysis in three age groups].

    PubMed

    Márquez-González, María; Izal Fernández de Trocóniz, María; Montorio Cerrato, Ignacio; Losada Baltar, Andrés

    2008-11-01

    The studies focused on age-related differences in emotional experience are still scarce, and most of them have been conducted with North-American samples. This study explores the presence of age-related differences in some facets of emotional experience (subjective well-being and emotional intensity), as well as in variables related to emotion regulation (subjective emotional control and three emotion-regulation mechanisms: situation selection, emotion suppression, rumination) in the Spanish population. One hundred and sixty people from three age groups (younger, middle-aged and older adults) participated in the study. Older participants reported lower levels of life satisfaction and positive emotional intensity than younger ones, as well as higher levels of perceived emotional control, emotional maturity and leveling of positive affect, and more use of emotion suppression. The results partially support the emotional maturity hypothesis of emotional functioning in old age, but also suggest that older adults' emotional regulation may present important peculiarities which have not yet been addressed in the extant literature, such as the moderation or limitation of emotional experience, especially positive emotions. PMID:18940059

  12. High brightness cathode experiments on the experimental test accelerator (ETA). Final report

    SciTech Connect

    Schlitt, L.; Proulx, G.

    1984-01-01

    The experiments performed on the ETA during the months of September through October of 1984 were intended to accomplish two objectives; to discover or develop a source capable of producing an electron beam whose brightness is substantially higher than that of previous sources, and to determine, if possible, the mechanisms which limit the source brightness so that further enhancements might be obtained. The results of the experiments met these objectives to a limited degree. A cathode material (velvet) and a diode geometry were identified which resulted in more than a factor of two improvements in brightness over that obtained with previous flashboard cathodes. Experiments were performed which have yielded information about mechanisms which may limit beam brightness, and have suggested approaches for further work to improve brightness. However, the desired brightness of 10/sup 5/ A/(cm/sup 2/-rad/sup 2/) was not achieved in these experiments. This report contains a discussion of the cathodes used, the diode geometries employed, the diagnostics, the typical characteristics of a single beam experiment, and the characteristics of the collimator used to measure the brightness. The entire ensemble of brightness data is presented and broken down into classes of experiments. In addition, the results of an EBQ calculation of one diode geometry are discussed, and differences between the results of similar experiments on ETA and ATA are noted. Finally, conclusions and recommendations are presented.

  13. Experience in using workstations as hosts in an accelerator control environment

    SciTech Connect

    Abola, A.; Casella, R.; Clifford, T.; Hoff, L.; Katz, R.; Kennell, S.; Mandell, S.; McBreen, E.; Weygand, D.P.

    1987-03-01

    A new control system has been used for light ion acceleration at the Alternating Gradient Synchrotron (AGS). The control system uses Apollo workstations in the dual role of console hardware computer and controls system host. It has been found that having a powerful dedicated CPU with a demand paging virtual memory OS featuring strong interprocess communication, mapped memory shared files, shared code, and multi-window capabilities, allows us to provide an efficient operation environment in which users may view and manage several control processes simultaneously. The same features which make workstations good console computers also provide an outstanding platform for code development. The software for the system, consisting of about 30K lines of ''C'' code, was developed on schedule, ready for light ion commissioning. System development is continuing with work being done on applications programs.

  14. Physico-Mechanical Characteristics of Freeze-Thaw Weathered Gneiss based on Accelerated Laboratory Experiments

    NASA Astrophysics Data System (ADS)

    Um, J. G.

    2014-12-01

    An experimental study of physical weathering was performed on fresh and slightly weathered gneiss samples from the Wonju area of South Korea. The study investigated changes in the physico-mechanical properties of these samples during accelerated laboratory-based weathering, including analyses of microfracture formation. The deteriorated samples used in the study were subjected to 100-150 freeze-thaw cycles, with index properties and microfracture geometries measured between each cycle. Each complete freeze-thaw cycle lasted 24 hours, and consisted of 2 hours of saturation in a vacuum chamber, 8 hours of freezing at -21°C ±1°C, and 14 hours of thawing at room temperature. Specific gravity and seismic velocity values were negatively correlated with the number of freeze-thaw cycles, whereas absorption values tended to increase. The amount of deterioration of the rock samples was dependent on the degree of weathering of the rock prior to the start of the analysis. Absorption, specific gravity, and seismic velocity values can be used to infer the amount of physical weathering experienced by a gneiss in the study area. The sizes and density of microfracture in the rock specimens varied with the number of freeze-thaw cycles. It was found that box fractal dimensions can be used to quantify the formation and propagation of microfracture in the samples. In addition, these box fractal dimensions can be used as a weathering index for the mid- and long-term prediction of rock weathering. The present results indicate that accelerated-weathering analysis can provide a detailed overview of the weathering characteristics of deteriorated rocks.

  15. Operational experience for coupled operation of the Holifield tandem electrostatic accelerator and isochronous cyclotron

    SciTech Connect

    Martin, J.A.; Dowling, D.T.; Haynes, D.L.; Hudson, E.D.; Jones, C.M.; Juras, R.C.; Lane, S.S.; Ludemann, C.A.; Meigs, M.J.; Milner, W.T.

    1986-10-01

    Coupled operation of the 25 MV tandem accelerator and the Oak Ridge Isochronous Cyclotron of the Holifield Heavy Ion Research Facility began in January 1981. Since that time the use of the cyclotron in this mode has become routine. Thirty-six different ion species in the range from /sup 9/Be to /sup 150/Nd have been accelerated; 106 separate beam setups have been provided. Since the beginning of coupled operation, significant improvement of cyclotron systems, and setup and operating techniques, have been made. The graphite electrostatic deflector septum formerly used for high-current light ion beams has been replaced by a thin molybdenum septum. Extraction system positioning mechanisms have been refined and recalibrated and more precise and reliable position readouts have been provided. The computer-based control system has been improved. The frequency range of the rf system has been increased to eliminate an energy dead-band. Cyclotron setup calculations have been improved and standardized methods have been developed to consistently achieve well-centered orbits, correct beam extraction system positions, and electrostatic and magnetic strengths. A totally new beam bunching system has been installed. The improvements in the phase-lock system of the beam buncher have been especially effective. A large number of obsolete and unreliable power supplies have been replaced. Beam extraction efficiency has been increased from approx.50% to approx.70%. Accuracy of obtaining the desired energy without fine tuning is now approx.1% compared to 2 to 3% in early coupled operation. Beam setup time (tuning) has been reduced by approx.20%. Unscheduled maintenance has been reduced by a factor of two.

  16. AN INTEGRAL REACTOR PHYSICS EXPERIMENT TO INFER ACTINIDE CAPTURE CROSS-SECTIONS FROM THORIUM TO CALIFORNIUM WITH ACCELERATOR MASS SPECTROMETRY

    SciTech Connect

    G. Youinou; M. Salvatores; M. Paul; R. Pardo; G. Palmiotti; F. Kondev; G. Imel

    2010-04-01

    The principle of the proposed experiment is to irradiate very pure actinide samples in the Advanced Test Reactor (ATR) at INL and, after a given time, determine the amount of the different transmutation products. The determination of the nuclide densities before and after neutron irradiation will allow inference of effective neutron capture cross-sections. This approach has been used in the past and the novelty of this experiment is that the atom densities of the different transmutation products will be determined using the Accelerator Mass Spectroscopy (AMS) technique at the ATLAS facility located at ANL. It is currently planned to irradiate the following isotopes: 232Th, 235U, 236U, 238U, 237Np, 238Pu, 239Pu, 240Pu, 241Pu, 242Pu, 241Am, 243Am and 248Cm.

  17. Aging--and Experience-Related Changes in Teacher Attitudes toward the Profession.

    ERIC Educational Resources Information Center

    Lipka, Richard P.; Goulet, L. R.

    1979-01-01

    A wide range of teachers were sampled to study whether attitudes toward the profession change with age and/or generation, or the amount of professional experience. Attitudes concerning the fulfillment of altruistic and pragmatic needs were assessed both for present views and for when the career choice was made. (Author/GDC)

  18. How Do People with Learning Disabilities Experience and Make Sense of the Ageing Process?

    ERIC Educational Resources Information Center

    Newberry, Gayle; Martin, Carol; Robbins, Lorna

    2015-01-01

    Background: Not enough is currently known about how people with learning disabilities experience and understand the ageing process. This is particularly important as the population of older people with learning disabilities is growing due to increased life expectancy. This article draws on the first author's doctoral research study, which aimed to…

  19. Ageing-Related Experiences of Adults with Learning Disability Resident in Rural Areas: One Australian Perspective

    ERIC Educational Resources Information Center

    Wark, Stuart; Canon-Vanry, Miranda; Ryan, Peta; Hussain, Rafat; Knox, Marie; Edwards, Meaghan; Parmenter, Marie; Parmenter, Trevor; Janicki, Matthew; Leggatt-Cook, Chez

    2015-01-01

    Background: Access to support services in rural areas is known to be problematic both in Australia, and in other countries around the world, but the majority of research on the population of people ageing with learning disability has so far focussed on metropolitan residents. The authors report about select aspects of the lived experience of older…

  20. False Memories in Children and Adults: Age, Distinctiveness, and Subjective Experience.

    ERIC Educational Resources Information Center

    Ghetti, Simona; Qin, Jianjian; Goodman, Gail S.

    2002-01-01

    Investigated developmental trends associated with the Deese/Roediger-McDermott false-memory effect, the role of distinctive information, and subjective experience of true/false memories. Found that 5-year-olds recalled more false memories than adults but no age differences in recognition of critical lures. Distinctive information reduced false…