Science.gov

Sample records for stress oxydatif dans

  1. Baisse du HDL-cholestérol indicateur du stress oxydatif dans le diabète de type 2

    PubMed Central

    Kabamba, Arsène Tshikongo; Bakari, Salvius Amuri; Longanga, Albert Otshudi; Lukumwena, Zet Kalala

    2014-01-01

    L'hypercholestérolémie est étroitement liée au stress oxydatif. Lorsqu'il y a trop de cholestérol qui circule dans le sang, il n'est pas utilisé en totalité par les cellules et il risque de s'accumuler dans les vaisseaux sanguins. Cela peut entrainer la formation des plaques d'athérosclérose qui gênent la circulation sanguine et provoquent des accidents cardiovasculaires. Le stress oxydatif apparait très tôt dans l'histoire des complications du diabète de type 2, et est lié à l'oxydation du glucose mais aussi à la peroxydation lipidique. Le cholestérol-HDL est un marqueur important du stress oxydatif par sa capacité à faciliter la métabolisation du cholestérol, sa baisse est souvent considérée comme la source de beaucoup d'inquiétudes. L'objectif est l’évaluation de la variation du taux de cholestérol-HDL, marqueur du stress oxydatif, chez les patients diabétiques de type 2 dans la population congolaise. Nous avons inclus dans cette étude prospective des cas témoins des patients diabétiques de type 2 reconnus et diagnostiqués, et des témoins non diabétiques appariés selon l’âge et le sexe. Parallèlement au bilan biologique classique, une analyse d'un des facteurs de risque du stress oxydatif a été réalisée: baisse de HDL-Cholestérol. L’âge moyen des 30 patients diabétiques (47,77±10,78 ans) était comparable à celui des 30 témoins (48,83±10,73 ans). Une baisse significative du cholestérol-HDL dans le sang était observée chez 100% des diabétiques et 50% des témoins (p=0,0000). L'augmentation du HDL cholestérol permet d’éliminer le mauvais cholestérol en excès en nettoyant les tissus et en ramenant le cholestérol vers le foie. Lors du diabète de type 2 on constate une baisse sanguine sensible du taux de HDL-cholestérol, qui est signe indicateur du stress oxydatif. PMID:25767660

  2. Stress

    MedlinePlus

    ... sudden negative change, such as losing a job, divorce, or illness Traumatic stress, which happens when you ... stress, so you can avoid more serious health effects. NIH: National Institute of Mental Health

  3. Stress.

    PubMed

    Chambers, David W

    2008-01-01

    We all experience stress as a regular, and sometimes damaging and sometimes useful, part of our daily lives. In our normal ups and downs, we have our share of exhaustion, despondency, and outrage--matched with their corresponding positive moods. But burnout and workaholism are different. They are chronic, dysfunctional, self-reinforcing, life-shortening habits. Dentists, nurses, teachers, ministers, social workers, and entertainers are especially susceptible to burnout; not because they are hard-working professionals (they tend to be), but because they are caring perfectionists who share control for the success of what they do with others and perform under the scrutiny of their colleagues (they tend to). Workaholics are also trapped in self-sealing cycles, but the elements are ever-receding visions of control and using constant activity as a barrier against facing reality. This essay explores the symptoms, mechanisms, causes, and successful coping strategies for burnout and workaholism. It also takes a look at the general stress response on the physiological level and at some of the damage American society inflicts on itself. PMID:18846841

  4. Diffusion dans les liquides

    NASA Astrophysics Data System (ADS)

    Dianoux, A. J.

    2003-09-01

    Après une brève introduction qui rappelle les concepts détaillés dans le cours de M. Bée, nous présentons un aperçu de trois de nos travaux sur l'étude de la diffusion. Tout d'abord la dynamique de l'eau, dans son état normal ou surfondu, révèle la complexité apportée par le réseau de liaisons hydrogène. Ensuite l'effet du confinement sur la dynamique de l'eau sera étudié dans le cas de la membrane Nafion. Enfin la diffusion dans les phases nématique et smectique A d'un cristal liquide permet d'obtenir la valeur du potentiel qui maintient les couches dans la phase smectique.

  5. Dan Johnson the mentor

    NASA Astrophysics Data System (ADS)

    McKinley, Richard

    2003-04-01

    I first met Dan Johnson in early 1975 as I was interviewing for an engineering job with Henning von Gierke's bioengineering and bionics laboratory at Wright-Patterson Air Force Base. From the very beginning Dan was always direct and forthright. Over the ensuing next 27 years my knowledge and respect of Dan constantly grew. This presentation will review Dan's technical and personal contributions while at the laboratory at Wright-Patterson Air Force Base. He was instrumental in the development of a national noise exposure criteria with the equal-energy-rule, an accurate single number hearing protector attenuation measure based on ``C-A,'' an impulse noise exposure criteria, a longitudinal study of hearing loss in children, development of noise dosimeters, and description of hearing damage risk from nonoccupational noise exposures such as disco's, bowling alleys, lawn mowers, and school buses. Dan has had a significant effect on my career. I and the many people who knew him at the laboratory miss him greatly.

  6. Stress echocardiography

    MedlinePlus

    Echocardiography stress test; Stress test - echocardiography; CAD - stress echocardiography; Coronary artery disease - stress Echocardiography; Chest pain - stress echocardiography; Angina - stress echocardiography; ...

  7. NPPy With Dan DeVito

    NASA Video Gallery

    The NPP mission mascot NPPy was found by the NPP Ground Project Manager Dan DeVito in a place called Svalbard, located 600 miles from the North Pole. Since then, Dan and other people on the NPP pro...

  8. Corner Office: Google's Dan Clancy

    ERIC Educational Resources Information Center

    Albanese, Andrew Richard; Oder, Norman

    2009-01-01

    This article presents an interview with Dan Clancy, engineering director for Google Book Search. In this interview, Clancy talks about the pending Google Book Search settlement, involving millions of volumes digitized from libraries, which drew a lawsuit from the Association of American Publishers and the Authors Guild. He also discusses pricing,…

  9. Stress and stress counselling.

    PubMed Central

    Matheson, K. H.

    1990-01-01

    This is a report by the 1989 National Association of Clinical Tutors Wyeth Travelling Fellow to the United States of America. The stresses of postgraduate training and attempts to modify these are described, including stress counselling. The significance of stress and the relevance of the findings for postgraduate training in the United Kingdom are considered. PMID:2235808

  10. Stress Management

    MedlinePlus

    ... Awards Healthy Workplace Food and Beverage Toolkit Stress Management Banner 1 - To Stress or Not to Stress - ... Decide But We Can Help What Is Stress Management? Banner 2 - Stress Continuum Graphic Banner Live life ...

  11. Radiations cosmiques : danger dans l'Espace

    NASA Astrophysics Data System (ADS)

    Bonnet-Bidaud, J. M.; Dzitko, H.

    2000-06-01

    Au sol, l'atmosphere nous protege plus ou moins bien. Mais dans l'espace ou a bord des avions de ligne, l'homme est directement expose aux rayonnements cosmiques qui peuvent etre mortels. Un veritable frein a la presence humaine prolongee dans l'espace. Une menace que les agences spatiales prennent tres au serieux.

  12. Effect of progressive drought stress on growth, leaf gas exchange, and antioxidant production in two maize cultivars.

    PubMed

    Anjum, Shakeel Ahmad; Tanveer, Mohsin; Ashraf, Umair; Hussain, Saddam; Shahzad, Babar; Khan, Imran; Wang, Longchang

    2016-09-01

    Drought stress is one of the major environmental factors responsible for reduction in crop productivity. In the present study, responses of two maize cultivars (Rung Nong 35 and Dong Dan 80) were examined to explicate the growth, yield, leaf gas exchange, leaf water contents, osmolyte accumulation, membrane lipid peroxidation, and antioxidant activity under progressive drought stress. Maize cultivars were subjected to varying field capacities (FC) viz., well-watered (80 % FC) and drought-stressed (35 % FC) at 45 days after sowing. The effects of drought stress were analyzed at 5, 10, 15, 20, ad 25 days after drought stress (DAS) imposition. Under prolonged drought stress, Rung Nong 35 exhibited higher reduction in growth and yield as compared to Dong Dan 80. Maize cultivar Dong Dan 80 showed higher leaf relative water content (RWC), free proline, and total carbohydrate accumulation than Run Nong 35. Malondialdehyde (MDA) and superoxide anion were increased with prolongation of drought stress, with higher rates in cultivar Run Nong 35 than cultivar Dong Dan 80. Higher production of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) and glutathione reductase (GR) resulted in improved growth and yield in Dong Dan 80. Overall, the cultivar Dong Dan 80 was better able to resist the detrimental effects of progressive drought stress as indicated by better growth and yield due to higher antioxidant enzymes, reduced lipid peroxidation, better accumulation of osmolytes, and maintenance of tissue water contents. PMID:27215981

  13. Stress and stress reduction.

    PubMed

    Straub, Heather; Qadir, Sameen; Miller, Greg; Borders, Ann

    2014-09-01

    Chronic stress contributes to preterm birth (PTB), through direct physiological mechanisms or behavioral pathways. This review identified interventions to prevent PTB through decreased maternal stress. Studies were grouped according to intervention: group prenatal care (11 studies), care coordination (8 studies), health insurance expansion (4 studies), expanded prenatal education/support in the clinic (8 studies), home visitation (9 studies), telephone contact (2 studies), or stress-reduction strategies (5 studies). Group prenatal care had the most evidence for PTB prevention. Comparative studies of PTB prevention through different models of prenatal care and maternal support, education, empowerment, stress-reduction, and coping strategies are needed. PMID:24979355

  14. Manage Stress

    MedlinePlus

    ... Manage Stress Print This Topic En español Manage Stress Browse Sections The Basics Overview Signs and Health ... and Health Effects What are the signs of stress? When people are under stress, they may feel: ...

  15. Nuclear stress test

    MedlinePlus

    ... Persantine stress test; Thallium stress test; Stress test - nuclear; Adenosine stress test; Regadenoson stress test; CAD - nuclear stress; Coronary artery disease - nuclear stress; Angina - nuclear ...

  16. Childhood Stress

    MedlinePlus

    ... for a Move What Kids Say About: Handling Stress Anxiety, Fears, and Phobias How to Talk to Your ... About School? 5 Ways to Deal With Anxiety Anxiety Disorders Can Stress Affect My Weight? Stress Contact Us Print Resources ...

  17. Dan Johnson's impact on hearing research

    NASA Astrophysics Data System (ADS)

    Shotland, Lawrence I.

    2003-04-01

    Daniel L. Johnson is well known for his many technical contributions to noise research. Throughout a long and distinguished career at Wright-Patterson Air Force Base, Dan published the results of several significant experiments, including his landmark experiments on asymptotic threshold shift and exposure to impulse noise. His work in the area of noise exposure laid much of the groundwork for a greater understanding of the physiologic response to hazardous noise, much of which has since been incorporated in national and international standards. Dan is highly regarded for his tireless work on technical and advisory committees in noise, and most recently, ototoxicity. Throughout his career, Dan has adhered to a self-imposed standard of intellectual honesty and discovery. Dan's most recent endeavor, the development of a personal noise dosimeter designed for self-monitoring by the employee, is characteristic of his creativity and energy. Perhaps less well known are his contributions over the years to the success of his younger colleagues. He has accomplished this in an unselfish and egalitarian manner, oftentimes challenging and even contradicting his own research. The focus of this talk will elaborate on these facets of Dan's professional contributions.

  18. Principal Stress.

    ERIC Educational Resources Information Center

    Clarke, Larry

    This paper describes the symptoms and ways of coping with chronic stress and briefly discusses effects of job related stress on school principals. Although stress is a normal condition, the symptoms should be identified. Under long-term stress individuals may experience six types of reactions, such as feelings of fatique and difficulty sleeping.…

  19. Dan jiang kou hydropower station turbine refurbishment

    NASA Astrophysics Data System (ADS)

    Zhang, R. Y.; Nie, S. Q.; Bazin, D.; Cheng, J. H.

    2012-11-01

    Dan jiangkou hydropower station refurbished project, isan important project of Chinese refurbishment market. Tianjin Alstom Hydro Co., ltd won this contract by right of good performance and design technology,Its design took into account all the constraints linked to the existing frame. It results in a specific and highly advanced shape.The objective of this paper is to introduce the successful turbine hydraulic design, model test and mechanical design of Dan jiangkou project; and also analyze the cavitation phenomena occurred on runner band surface of Unit 4 after putting into commercial operation. These technology and feedback shall be a good reference and experience for other similar projects

  20. MSL DAN Passive Data and Interpretations

    NASA Astrophysics Data System (ADS)

    Tate, C. G.; Moersch, J.; Jun, I.; Ming, D. W.; Mitrofanov, I. G.; Litvak, M. L.; Behar, A.; Boynton, W. V.; Drake, D.; Lisov, D.; Mischna, M. A.; Hardgrove, C. J.; Milliken, R.; Sanin, A. B.; Starr, R. D.; Martín-Torres, J.; Zorzano, M. P.; Fedosov, F.; Golovin, D.; Harshman, K.; Kozyrev, A.; Malakhov, A. V.; Mokrousov, M.; Nikiforov, S.; Varenikov, A.

    2014-12-01

    In its passive mode of operation, The Mars Science Laboratory Dynamic Albedo of Neutrons experiment (DAN) detects low energy neutrons that are produced by two different sources on Mars. Neutrons are produced by the rover's Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) and by interactions of high energy galactic cosmic rays (GCR) within the atmosphere and regolith. As these neutrons propagate through the subsurface, their energies can be moderated by interactions with hydrogen nuclei. More hydrogen leads to greater moderation (thermalization) of the neutron population energies. The presence of high thermal neutron absorbing elements within the regolith also complicates the spectrum of the returning neutron population, as shown by Hardgrove et al. DAN measures the thermal and epithermal neutron populations leaking from the surface to infer the amount of water equivalent hydrogen (WEH) in the shallow regolith. Extensive modeling is performed using a Monte Carlo approach (MCNPX) to analyze DAN passive measurements at fixed locations and along rover traverse segments. DAN passive WEH estimates along Curiosity's traverse will be presented along with an analysis of trends in the data and a description of correlations between these results and the geologic characteristics of the surfaces traversed.

  1. Registration of 'Dan' winter hulless barley

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dan’ (Reg. No. CV- , PI 659066) six-rowed winter hulless barley (Hordeum vulgare L.) was developed and released by the Virginia Agricultural Experiment Station in March 2009. Dan was derived from the cross VA96-41-17 / SC872143. It was released for production in the eastern United States, as a poten...

  2. Caregiver Stress

    MedlinePlus

    ... 2005). Psychophysiological mediators of caregiver stress and differential cognitive decline . Psychology and Aging, 20 (3), 402–411. Pew Research ... 2005). Psychophysiological mediators of caregiver stress and differential cognitive decline . Psychology and Aging, 20 (3), 402–411. Return to ...

  3. Feeling Stressed

    MedlinePlus

    ... other physical activity. Can stress lead to more serious problems? top Stress that's too much for you to handle may play a role in some serious problems. These problems include eating disorders , hurting yourself , ...

  4. Manage Stress

    MedlinePlus

    ... sections Take Action: Get Support 8. Talk to friends and family. Tell your friends and family if you are feeling stressed. They may be able to help. Learn how friends and family can help you feel less stressed. ...

  5. Controlling Stress

    ERIC Educational Resources Information Center

    Kelehear, Zach

    2004-01-01

    Stress occurs among all groups in a school community and can affect morale, performance, and leadership ability. This article discusses how educators must deal with and control stress. Principals must address their own stress to create a healthy school culture. Moreover, the author presents two survival strategies that can provide support and…

  6. Understanding Stress.

    ERIC Educational Resources Information Center

    Bellott, Fred K.

    Stress affects everyone in his/her work and everyday life. Some persons are more effective when they are under a certain level of stress, but there are limits to the amount of stress under which one can perform effectively. Competition within complex organizations today is a risk factor not often recognized by the organizations. All organizations…

  7. Dan Marino Helping Those with Autism Spectrum Disorders | NIH MedlinePlus the Magazine

    MedlinePlus

    ... Marino Foundation. Photo: Dan Marino Foundation Former NFL star quarterback Dan Marino and his wife Claire experienced ... to succeed in life,'" says the former NFL star. "That's where the focus for The Dan Marino ...

  8. Debriefing Stress.

    ERIC Educational Resources Information Center

    Hill, Jonnie L.; Lance, Cynthia G.

    2002-01-01

    Discussion pf the stress associated with the educational use of games and simulations focuses on a study of graduate students that used the Myers-Briggs Type Indicator to determine that people with certain personality types experience stress at different intensities. Also found that all participants, regardless of personality type, needed…

  9. 8. Wabash Ave. North. View of Loop and Dan Ryan ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Wabash Ave. North. View of Loop and Dan Ryan Line. Curve at Van Buren St. and Wabash Ave. at center. Dan Ryan line starts at center and runs south (toward bottom of picture). Photo by Jet Lowe. - Union Elevated Railroad, Union Loop, Wells, Van Buren, Lake Streets & Wabash Avenue, Chicago, Cook County, IL

  10. Airplane Stress Analysis

    NASA Technical Reports Server (NTRS)

    Zahm, A F; Crook, L H

    1918-01-01

    Report presents stress analysis of individual components of an airplane. Normal and abnormal loads, sudden loads, simple stresses, indirect simple stresses, resultant unit stress, repetitive and equivalent stress, maximum steady load and stress are considered.

  11. L'astronomie dans le monde

    NASA Astrophysics Data System (ADS)

    Manfroid, J.

    2014-06-01

    Future lune ? - L'âge de la Lune - Des volcans actifs sur Vénus - Un lac dans le cratère Gusev ? - Météorites et atmosphère martiennes - L’hexagone de Saturne - Pluton - Exo-Terre - Bêta Pictoris b - Cérès et Vesta depuis Mars - Naine froide - Parallaxes par Hubble - L2 Puppis et le sort du Soleil - Supernova et lentille gravitationnelle - Champ magnétique galactique - L’objet de Sakurai - Fermi et la matière noire - Lentille naine

  12. Cold Stress

    MedlinePlus

    ... be at risk of cold stress. Extreme cold weather is a dangerous situation that can bring on ... the country. In regions relatively unaccustomed to winter weather, near freezing temperatures are considered factors for cold ...

  13. Heat Stress

    MedlinePlus

    ... Stress Learn some tips to protect workers including: acclimatization, rest breaks, and fluid recommendations. NIOSH Workplace Solution: ... Blog: Adjusting to Work in the Heat: Why Acclimatization Matters The natural adaptation to the heat takes ...

  14. Students' Stress.

    ERIC Educational Resources Information Center

    Shirom, Arie

    1986-01-01

    A study of undergraduate students' perceived stresses, as solicited by graduate students, found the greatest stressors to be examination-related, followed by those related to meeting class assignments and to the teaching process. (MSE)

  15. Pat Thiel talks about Nobel Prize winner Dan Shechtman

    SciTech Connect

    Thiel, Pat

    2012-01-01

    Ames Laboratory senior scientist and Iowa State University Distinguished Professor of Chemistry Pat Thiel talks about her friend and colleague Dan Shechtman who received the 2011 Nobel Prize for Chemistry.

  16. 4. Historic American Buildings Survey Dan Leyrer, Photographer, July 10, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. Historic American Buildings Survey Dan Leyrer, Photographer, July 10, 1963 ENTRANCE HALL & STAIRWAY with BRASS NEWEL POST - Herman-Grima House, 820 Saint Louis Street, New Orleans, Orleans Parish, LA

  17. 1. Historic American Buildings Survey Dan Leyrer, Photographer August 1963 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Historic American Buildings Survey Dan Leyrer, Photographer August 1963 PATIO AND GARCONNIERE--VIEW FROM EAST - Herman-Grima House, Garconniere & Kitchen, 820 Saint Louis Street, New Orleans, Orleans Parish, LA

  18. 2. Historic American Buildings Survey Dan Leyrer, Photographer August 1963 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Historic American Buildings Survey Dan Leyrer, Photographer August 1963 KITCHEN (SOUTHEAST ELEVATION) ATTACHED TO GARCONNIERE - Herman-Grima House, Garconniere & Kitchen, 820 Saint Louis Street, New Orleans, Orleans Parish, LA

  19. Environmental Scientist/Chemist Dan Gazda Speaks With Students

    NASA Video Gallery

    From NASA's International Space Station Mission Control Center, Environmental Scientist/Chemist Dan Gazda participates in a Digital Learning Network (DLN) event with students at from St. Peter's Pr...

  20. 1. Historic American Buildings Survey Dan Leyrer, Photographer Summer 1964 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Historic American Buildings Survey Dan Leyrer, Photographer Summer 1964 FRONT ELEVATION, OVERLOOKING BAYOU ST. JOHN - Michel-Pitot House, 1370 Moss Street (moved to 1440 Moss Street), New Orleans, Orleans Parish, LA

  1. Pat Thiel talks about Nobel Prize winner Dan Shechtman

    ScienceCinema

    Thiel, Pat

    2013-03-01

    Ames Laboratory senior scientist and Iowa State University Distinguished Professor of Chemistry Pat Thiel talks about her friend and colleague Dan Shechtman who received the 2011 Nobel Prize for Chemistry.

  2. STS-108 Crew Interviews: Dan Tani

    NASA Technical Reports Server (NTRS)

    2001-01-01

    STS-108 Mission Specialist Dan Tani is seen during a prelaunch interview. He answers questions about the mission's goals and significance, explaining the meaning of 'utilization flight 1' (UF-1) as opposed to an 'assembly flight'. He gives details on the payload (Starshine Satellite, Avian Development Facility, and Rafaello Multipurpose Logistics Module (MPLM)), his role in the rendezvous, docking, and undocking of the Endeavour Orbiter to the International Space Station (ISS), how he will participate in the unloading and reloading of the MPLM, and the way in which the old and new resident crews of ISS will exchanged. Tani ends with his thoughts on the short-term and long-term future of the International Space Station.

  3. Stress and Infertility

    MedlinePlus

    ... the American Society for Reproductive Medicine Stress and infertility It is not clear how exactly stress impacts ... How can stress impact a fertility patient? Sometimes, infertility patients respond to the stress of being unable ...

  4. Stress and Your Health

    MedlinePlus

    ... ePublications > Stress and your health fact sheet ePublications Stress and your health fact sheet Print this fact ... a big difference in my life! What is stress? Stress is a feeling you get when faced ...

  5. Stress and your heart

    MedlinePlus

    Coronary heart disease - stress; Coronary artery disease - stress ... Your body responds to stress on many levels. First, it releases stress hormones that make you breathe faster. Your blood pressure goes up. Your muscles ...

  6. Catecholamines and stress.

    PubMed

    Palkovits, Miklós

    2014-03-30

    A brief survey is offering of debates on two long-standing questions in stress studies and theories: 1) question of stress nonspecificity (i.e. homo- or heterogeneity in stress responses), and 2) what is the functional role of central catecholamines in stress mechanisms, especially in stress signal-transduction and in the realization of stress responses. PMID:26118253

  7. L'astronomie dans le monde

    NASA Astrophysics Data System (ADS)

    Manfroid, J.

    2007-09-01

    Anions interstellaires; S Orionis; Altaîr; Courants stellaires; Etoiles jeunes; 2MASSW J1207334-393254; Alpha Andromède; Etoiles à neutrons (1); LH54-425; AGNs invisibles; Deux supernovae; Les GRBs seon Swift; Peser les trous noirs; Formation de trous noirs; Trou noir; ondes gravitationnelles : Virgo entre dans sa phase d'exploitation scientifique; Amas de galaxies actifs; Amas de galaxies; Galaxies actives d'amas; L'univers statique: le retour; Macho; Exoplanètes; Exoplanètes habitables?; Exoplanètes habitables? (suite); Une année d'un an; Une année de 31 heures; Valse des Jupiters; Disque de HD 15115; Impact majeur; Planètes isolées; Super-Jupiter; Impact et mini-extinction; L'effet Pioneer; Toungouska; Spéléo martienne; Autres lunes dactives; Encelade; Hypérion; Pluton dépassé; Satellites d'Uranus; Titan

  8. Chronic Stress and Posttraumatic Stress Disorders.

    ERIC Educational Resources Information Center

    Davidson, Laura M.; Baum, Andrew

    1986-01-01

    Examined the relationship between chronic stress and symptoms of posttraumatic stress syndrome in people living within five miles of the Three Mile Island (TMI) nuclear power station. Results provided evidence of substantive links between chronic stress and development of mild symptoms of posttraumatic stress disorder. (Author/BL)

  9. Place du Lambeau Interosseux Posterieur dans sa Variante Aponevrotique dans le Traitement des Sequelles de Brulure de la Face Dorsale de la Main

    PubMed Central

    Achbouk, A.; Khales, A.; Oufkir, A.; Ihrai, H.

    2010-01-01

    Summary Le lambeau interosseux postérieur dans sa variante aponévrotique est un outil très intéressant dans le traitement des séquelles de brûlures de la face dorsale de la main. Les Auteurs cherchent, à travers un cas clinique et une revue de la littérature, à replacer cette variante dans l'arsenal thérapeutique. PMID:21991207

  10. Kyste hydatique du foie rompu dans la paroi abdominale et dans le muscle psoas : à propos d'une rare observation

    PubMed Central

    En-Nafaa, Issam; Moujahid, Mountassir; Alahyane, Abdelouahabe; Amil, Touria; Hanine, Ahmed; Ziadi, Tarik

    2011-01-01

    Le kyste hydatique du foie est une parasitose qui sévit à l′état endémique au maroc. La rupture dans la paroi abdominale et dans le psoas est une complication exceptionnelle. Nous rapportons un cas de kyste hydatique du foie rompu dans la paroi et dans le muscle psoas. Le diagnostic a été établi sur les données de l′échographie et surtout de la tomodensitométrie. Le patient a été opéré avec des suites simples. PMID:22187585

  11. Combined environmental stresses

    NASA Technical Reports Server (NTRS)

    Murray, R. H.; Mccally, M.

    1973-01-01

    Tolerance levels, physiological effects, and performance degradation during simultaneous or sequential exposures to two environmental stresses, and also three or more simultaneous stresses are described. Environmental stress combinations are characterized by four descriptors: order of occurrence, duration of exposure, severity of exposure, and type of interaction. Combined stress data and facilities for combined stress study are briefly mentioned.

  12. Accurate Thermal Stresses for Beams: Normal Stress

    NASA Technical Reports Server (NTRS)

    Johnson, Theodore F.; Pilkey, Walter D.

    2003-01-01

    Formulations for a general theory of thermoelasticity to generate accurate thermal stresses for structural members of aeronautical vehicles were developed in 1954 by Boley. The formulation also provides three normal stresses and a shear stress along the entire length of the beam. The Poisson effect of the lateral and transverse normal stresses on a thermally loaded beam is taken into account in this theory by employing an Airy stress function. The Airy stress function enables the reduction of the three-dimensional thermal stress problem to a two-dimensional one. Numerical results from the general theory of thermoelasticity are compared to those obtained from strength of materials. It is concluded that the theory of thermoelasticity for prismatic beams proposed in this paper can be used instead of strength of materials when precise stress results are desired.

  13. Accurate Thermal Stresses for Beams: Normal Stress

    NASA Technical Reports Server (NTRS)

    Johnson, Theodore F.; Pilkey, Walter D.

    2002-01-01

    Formulations for a general theory of thermoelasticity to generate accurate thermal stresses for structural members of aeronautical vehicles were developed in 1954 by Boley. The formulation also provides three normal stresses and a shear stress along the entire length of the beam. The Poisson effect of the lateral and transverse normal stresses on a thermally loaded beam is taken into account in this theory by employing an Airy stress function. The Airy stress function enables the reduction of the three-dimensional thermal stress problem to a two-dimensional one. Numerical results from the general theory of thermoelasticity are compared to those obtained from strength of materials. It is concluded that the theory of thermoelasticity for prismatic beams proposed in this paper can be used instead of strength of materials when precise stress results are desired.

  14. ADFL Award for Distinguished Service in the Profession: Dan Davidson.

    ERIC Educational Resources Information Center

    Dabars, Zita D.

    1999-01-01

    Discusses the influence of Dan Davidson on the Russian language teaching profession, concentrating on the NEH-CORLAC Institutes in Russian Language and Culture and materials development projects and on Davidson's role in programs involving high schools that teach Russian, the high school exchange program, and two national contests to stimulate…

  15. Dan Poskevich demonstrates experiment for STS student involvement project

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Dan Poskevich, a college student, demonstrates an experiment he developed for the Space Transportation System (STS) student involvement project. In the aluminum box are thousands of honeybees constructing a honeycomb. Poskevich gave a brief demonstration for news media representatives in the Space Shuttle one-G trainer in JSC's mockup and integration lab.

  16. Overcoming job stress

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000884.htm Overcoming job stress To use the sharing features on this ... you stay healthy and feel better. Causes of Job Stress Although the cause of job stress is ...

  17. Stress and your health

    MedlinePlus

    ... main types of stress: Acute stress. This is short-term stress that goes away quickly. You feel it ... to tense, and increase your pulse. In the short term, these reactions are good because they can help ...

  18. Stress urinary incontinence

    MedlinePlus

    Incontinence - stress ... over 2 cups of urine in their bladder. Stress incontinence occurs when the muscles that control your ... area or the prostate (in men) Unknown causes Stress incontinence is the most common type in women. ...

  19. Stress and your health

    MedlinePlus

    ... org/familydoctor/en/prevention-wellness/emotional-wellbeing/mental-health/stress-how-to-cope-better-with-lifes-challenges.html. ... on Stress. Available at: www.nimh.nih.gov/health/publications/stress/index.shtml. Accessed April 17, 2014. US Department ...

  20. What Is Stress?

    ERIC Educational Resources Information Center

    Franks, B. Don

    1994-01-01

    After presenting positive and negative aspects of stress, the paper looks at definitions of stress that emphasize the environment, responses to the environment, individual characteristics, or a combination of these elements. A proposed definition of stress is offered. (SM)

  1. Transport de paires EPR dans des structures mesoscopiques

    NASA Astrophysics Data System (ADS)

    Dupont, Emilie

    Dans cette these, nous nous sommes particulierement interesses a la propagation de paires EPR1 delocalisees et localisees, et a l'influence d'un supraconducteur sur le transport de ces paires. Apres une introduction de cette etude, ainsi que du cadre scientifique qu'est l'informatique quantique dans lequel elle s'inscrit, nous allons dans le chapitre 1 faire un rappel sur le systeme constitue de deux points quantiques normaux entoures de deux fils supraconducteurs. Cela nous permettra d'introduire une methode de calcul qui sera reutilisee par la suite, et de trouver egalement le courant Josephson produit par ce systeme transforme en SQUID-dc par l'ajout d'une jonction auxiliaire. Le SQUID permet de mesurer l'etat de spin (singulet ou triplet), et peut etre forme a partir d'autres systemes que nous etudierons ensuite. Dans le chapitre 2, nous rappellerons l'etude detaillee d'un intricateur d'Andreev faite par un groupe de Bale. La matrice T, permettant d'obtenir le courant dans les cas ou les electrons sont separes spatialement ou non, sera etudiee en detail afin d'en faire usage au chapitre suivant. Le chapitre 3 est consacre a l'etude de l'influence du bruit sur le fonctionnement de l'intricateur d'Andreev. Ce bruit modifie la forme du courant jusqu'a aboutir a d'autres conditions de fonctionnement de l'intricateur. En effet, le bruit present sur les points quantiques peut perturber le transport des paires EPR par l'intermediaire des degres de liberte. Nous montrerons que, du fait de l'"intrication" entre la charge de la paire et le bruit, la paire est detruite pour des temps longs. Cependant, le resultat le plus important sera que le bruit perturbe plus le transport des paires delocalisees, qui implique une resonance de Breit-Wigner a deux particules. Le transport parasite n'implique pour sa part qu'une resonance de Breit-Wigner a une particule. Dans le chapitre 4, nous reviendrons au systeme constitue de deux points quantiques entoures de deux fils

  2. Juror stress.

    PubMed

    Hafemeister, T L

    1993-01-01

    That jurors may be harmed as a result of their carrying out their civic duties is receiving increased attention from the courts and the media (Sevilla & Beyers, 1990; Craver, 1993). The pilot tests reported here represent initial efforts to undertake a proactive project for identifying and mitigating the possible adverse effects of stress on jurors and to contribute to the understanding and treatment of secondary trauma for at-risk groups. In many ways juries are the black box of the legal system. Their decision-making process is typically shrouded in mystery. So that they may fully explore the issues and examine their consciences, jurors meet privately when reaching their decision and, beyond entering a verdict, are typically not required to provide the rationale for their verdict. Furthermore, jurors are often reluctant to discuss the bases for their verdicts after the trial is over and an unspoken code of honor may limit their willingness to critique their fellow jurors. Perhaps in part because we know so little about their decision-making process, as well as because of their intrinsic and symbolic importance to the legal system, there may be a tendency to take jurors for granted and to assume that they are relatively unaffected by their jury duties. Although jurors are expected to appear impassive and emotionally detached in court, for some trials it is only the rare individual who will not be emotionally moved by what he or she has seen and heard or by the gravity of the decision that is required. Several recent cases have provided a glimpse of what goes on within this black box and suggest that greater attention may need to be given to the needs of these jurors. PMID:8193058

  3. Prenatal Maternal Stress Programs Infant Stress Regulation

    ERIC Educational Resources Information Center

    Davis, Elysia Poggi; Glynn, Laura M.; Waffarn, Feizal; Sandman, Curt A.

    2011-01-01

    Objective: Prenatal exposure to inappropriate levels of glucocorticoids (GCs) and maternal stress are putative mechanisms for the fetal programming of later health outcomes. The current investigation examined the influence of prenatal maternal cortisol and maternal psychosocial stress on infant physiological and behavioral responses to stress.…

  4. Teacher Wellness: Too Stressed for Stress Management?

    ERIC Educational Resources Information Center

    Kipps-Vaughan, Debi; Ponsart, Tyler; Gilligan, Tammy

    2012-01-01

    Healthier, happier teachers promote healthier, happier, and more effective learning environments. Yet, many teachers experience considerable stress. Studies have found that between one fifth and one fourth of teachers frequently experience a great deal of stress (Kyriacou, 1998). Stress in teaching appears to be universal across nations and…

  5. The effect of academic stress and attachment stress on stress-eaters and stress-undereaters.

    PubMed

    Emond, Michael; Ten Eycke, Kayla; Kosmerly, Stacey; Robinson, Adele Lafrance; Stillar, Amanda; Van Blyderveen, Sherry

    2016-05-01

    It is well established that stress is related to changes in eating patterns. Some individuals are more likely to increase their overall food intake under conditions of stress, whereas others are more likely to consume less food when stressed. Attachment style has been linked to disordered eating and eating disorders; however, comparisons of eating behaviors under attachment versus other types of stress have yet to be explored. The present laboratory study examined the eating patterns in self-identified stress-undereaters and stress-eaters under various types of stress. More specifically, the study examined the effects of academic and attachment stress on calorie, carbohydrate and sugar consumption within these two groups. Under the guise of critiquing student films, university students viewed either one of two stress-inducing videos (academic stress or attachment stress, both designed to be emotionally arousing) or a control video (designed to be emotionally neutral), and their food intake was recorded. Results demonstrated that the video manipulations were effective in inducing stress. Differential patterns of eating were noted based on group and stress condition. Specifically, stress-undereaters ate fewer calories, carbohydrates and sugars than stress-eaters in the academic stress condition, but not in the attachment stress or control condition. Findings suggest that specific types of stressors may influence eating behaviors differently. PMID:26850311

  6. Apport de l'imagerie dans le diagnostic des sacroiliites infectieuses : à propos de 19 cas

    PubMed Central

    Abid, Hanen; Chaabouni, Salim; Frikha, Faten; Toumi, Nozha; Souissi, Basma; Lahiani, Dorra; Bahloul, Zouhir; Ben Mahfoudh, Khaireddine

    2014-01-01

    Les sacro-iliites infectieuses méritent d’être mieux connues. Leur diagnostic est souvent retardé en raison d'une symptomatologie trompeuse et des diffcultés d'exploration de l'articulation sacro-iliaque. Notre travail est basé sur une étude rétrospective portant sur les cas de SII, recueillis sur une période comprise entre 1997 et 2008 dans notre centre universitaire Sfax-Tunisie. Le diagnostic de sacro-iliite était retenu en présence d'arguments cliniques et radiologiques d'atteinte sacroiliaque. Nous rapportons dix neuf cas de sacroiliites infectieuses (10 hommes et 9 femmes), avec un âge moyen de 32 ans. L'atteinte était unilatérale dans tous les cas. Les radiographies standard faites dans tous les cas ont été suggestives dans 14 cas et normales dans les autres cas. La TDM faite dans 13 cas a montré, un abcès des parties molles dans 8 cas et un séquestre osseux dans 2 cas. L'IRM réalisée dans 8 cas, a objectivé une infiltration des parties molles dans tous les cas et un abcès dans 3 cas. Le germe a été identifié dans 9 cas (3 cas de tuberculose, 3 cas de brucellose, 2 sacro-iliites à pyogène et un cas de candidose). Cette identification était faite par biopsie dans 3 cas, hémocultures dans 2 cas, prélèvement au niveau de la porte d'entrée dans 1 cas et sérodiagnostic dans 3 cas. Pour les autres cas, l'origine pyogène a été retenue sur des arguments cliniques et biologiques. L'imagerie joue un rôle primordial dans le diagnostic précoce et l'orientation étiologique d'une sacroiliite infectieuse. PMID:25120884

  7. Repetitive Stress Injuries

    MedlinePlus

    ... any problems since. What Are Repetitive Stress Injuries? Repetitive stress injuries (RSIs) are injuries that happen when too much stress is placed on a part of the body, resulting in inflammation (pain and swelling), muscle strain, or tissue damage. This stress generally occurs from ...

  8. Managing Leadership Stress

    ERIC Educational Resources Information Center

    Bal, Vidula; Campbell, Michael; McDowell-Larsen, Sharon

    2008-01-01

    Everyone experiences stress, and leaders face the additional stress brought about by the unique demands of leadership: having to make decisions with limited information, to manage conflict, to do more with less ...and faster! The consequences of stress can include health problems and deteriorating relationships. Knowing what signs of stress to…

  9. What Is Stress Management?

    MedlinePlus

    ... zone mark into the high-stress zone, it’s time to take a stress-management moment. Maybe that means that you call a ... you reserve your “high zone stress responses” for times when it’s more appropriate. When life and death are ... • Home • How Does Stress Affect You? Introduction FAQs ...

  10. Stress in Bangladeshi Bengoli.

    ERIC Educational Resources Information Center

    Alam, Samsul

    This report discusses the stress patterns of Bengali as spoken in Bangladesh. One of the findings indicate that every word has stress in the first syllable, with additional stress in the first syllable of the first word of the phrase. The Bengali language does not have penultimate and antepenultimate stress. Because there is no rule for changing…

  11. NASA Administrator Dan Goldin talks with STS-78 crew

    NASA Technical Reports Server (NTRS)

    1996-01-01

    NASA Administrator Dan Goldin (left) chats with STS-78 Mission Commander Terence 'Tom' Henricks (center) and KSC Director Jay Honeycutt underneath the orbiter Columbia. Columbia and her seven-member crew touched down on Runway 33 of KSC's Shuttle Landing Facility at 8:36 a.m. EDT, July 7, bringing to a close the longest Shuttle flight to date. STS-78, which also was the 78th Shuttle flight, lasted 16 days, 21 minutes and 47 seconds.

  12. [Acupuncture and stress].

    PubMed

    Cheng, Cisong; Zhu Yihui; Wei, Qin; Kou, Jun; Wen, Peipei

    2015-04-01

    The relationship between acupuncture and stress is discussed from three aspects, including is it possible for acupuncture stimulation to be a stressor, whether acupuncture will start stress reaction, and whether acupuncture effects contain some stress factors. It is believed that correct acupuncture manipulation will not cause stress response, however, under some circumstances, such as inaccurate manipulation, improper treatment or patients who are very nervous but do not receive effective intervention, acupuncture is likely to cause stress response. Acupuncture-induced stress response is totally different from acupuncture anti-stress. The possible stress factors in acupuncture effect are explored, which can provide a new angle for the research on action mechanism of acupuncture. From the view of stress to review acupuncture treatment, there are three enlightenments: emphasizing on communication between doctors and patients, avoiding over-pursuit of deqi and focusing on analysis of the body constitution. PMID:26054156

  13. Stress pulse phenomena

    SciTech Connect

    McGlaun, M.

    1993-08-01

    This paper is an introductory discussion of stress pulse phenomena in simple solids and fluids. Stress pulse phenomena is a very rich and complex field that has been studied by many scientists and engineers. This paper describes the behavior of stress pulses in idealized materials. Inviscid fluids and simple solids are realistic enough to illustrate the basic behavior of stress pulses. Sections 2 through 8 deal with the behavior of pressure pulses. Pressure is best thought of as the average stress at a point. Section 9 deals with shear stresses which are most important in studying solids.

  14. Dissolution de la matiere lignocellulosique dans les liquides ioniques

    NASA Astrophysics Data System (ADS)

    Rebiere, Jeremy

    De nos jours, avec la raréfaction des ressources fossiles, le développement de procédés entrant dans le cadre de la chimie verte s'accentue. De plus, ces procédés utilisent comme ressources, des matériaux d'origine végétale, abondants et biodégradables. Au cours de ces 20 dernières années, la littérature utilisant les liquides ioniques (LI) connait une importante croissance. Ces solvants sont de plus en plus employés dans des réactions chimiques classiques. Cependant le coût de leur synthèse en fait un solvant réactionnel cher dont l'application en tant que tel dans l'industrie ne peut être raisonnablement envisagée. Ces liquides ioniques permettent la dissolution des matériaux lignocellulosiques (lignine ou cellulose) et possèdent des propriétés physico-chimiques intéressantes. Nous savons également que la dissolution de la cellulose par des procédés d'hydrolyse classique s'effectue dans des conditions dures, dues à la structure cristalline de la cellulose, (fortes concentrations en acide) qui paraissent limitées pour une utilisation à grande échelle. Il est donc nécessaire de rechercher des méthodes moins onéreuses et plus efficaces écologiquement. S'appuyant sur des recherches démontrant que la dissolution de la cellulose dans les LI, diminue la cristallinité de la cellulose, nous allons chercher à démontrer au cours de ces travaux, la possibilité d'utiliser les LI comme moyen de prétraitement pour la dissolution de la cellulose. Nous allons nous attacher à dissoudre la cellulose, et à étudier les proportions pouvant être dissoutes. Puis nous chercherons à récupérer puis à réutiliser ces LI. Enfin nous cherchons à caractériser les modifications apportées à notre cellulose. Mots Clés liquide ionique, cellulose, cristallinité, réactivité, dissolution, régénération, non-solvant, purification, prétraitement, zone amorphe.

  15. Stress in childhood

    MedlinePlus

    American Academy of Pediatrics. Helping children handle stress. Available at http://www.healthychildren.org/English/healthy-living/emotional-wellness/Pages/Helping-Children-Handle-Stress.aspx. Accessed on May 14, 2014. American ...

  16. Stress and Migraine

    MedlinePlus

    ... abuse, post-traumatic stress disorder and poor socio-economic circumstances are known contributors to stress and its ... much! Please support the 36 Million Migraine Campaign today! Copyright © 2011 American Headache Society®. All rights reserved. ...

  17. Institutional Preventive Stress Management.

    ERIC Educational Resources Information Center

    Quick, James C.

    1987-01-01

    Stress is an inevitable characteristic of academic life, but colleges and universities can introduce stress management activities at the organizational level to avert excessive tension. Preventive actions are described, including flexible work schedules and social supports. (Author/MSE)

  18. Understanding Child Traumatic Stress

    MedlinePlus

    ... Substance Abuse Culture and Trauma Definitions References Resources Economic Stress Military and Veteran Families and Children Secondary ... us of what happened. Back to Top How Development Influences Posttraumatic Stress Responses Age, developmental maturity, and ...

  19. 77 FR 75628 - STS Hydropower, Ltd., Dan River, Inc., and City of Danville, VA; Notice of Application for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-21

    ... Energy Regulatory Commission STS Hydropower, Ltd., Dan River, Inc., and City of Danville, VA; Notice of..., 2012, Jeoffrey L. Burtch, as Chapter 7 Bankruptcy Trustee for Dan River, Inc. and STS Hydropower, Ltd... the license for the Schoolfield Hydroelectric Project from Dan River, Inc. and STS Hydropower, Ltd....

  20. Visualizing balloon stresses

    NASA Astrophysics Data System (ADS)

    Winker, James A.

    1994-02-01

    In a structure as indeterminate as a partially inflalted balloon it is very difficult to determine either the stress at any given point or a stress pattern over an area. Finite element analysis for this purpose is under development, but this will not likely bear fruit for years. This paper describes a process using desktop computers to convert actual experimental stress data into graphic, visual displays. The results provide valuable insight into the nature of balloon stresses.

  1. Nuclear Stress Test

    MedlinePlus

    ... Scan Diagnostic Tests and Procedures Echocardiography Electrocardiogram Electrophysiology Studies Exercise Stress Test Holter Monitoring Intravascular Ultrasound Nuclear Ventriculography Optical ...

  2. Stress and Protists: No life without stress.

    PubMed

    Slaveykova, Vera; Sonntag, Bettina; Gutiérrez, Juan Carlos

    2016-08-01

    We report a summary of the symposium "Stress and Protists: No life without stress", which was held in September 2015 on the VII European Congress of Protistology in partnership with the International Society of Protistologists (Seville, Spain). We present an overview on general comments and concepts on cellular stress which can be also applied to any protist. Generally, various environmental stressors may induce similar cell responses in very different protists. Two main topics are reported in this manuscript: (i) metallic nanoparticles as environmental pollutants and stressors for aquatic protists, and (ii) ultraviolet radiation - induced stress and photoprotective strategies in ciliates. Model protists such as Chlamydomonas reinhardtii and Tetrahymena thermophila were used to assess stress caused by nanoparticles while stress caused by ultraviolet radiation was tested with free living planktonic ciliates as well as with the symbiont-bearing model ciliate Paramecium bursaria. For future studies, we suggest more intensive analyses on protist stress responses to specific environmental abiotic and/or biotic stressors at molecular and genetic levels up to ecological consequences and food web dynamics. PMID:27365178

  3. Dan Olweus: Award for Distinguished Contributions to Research in Public Policy

    ERIC Educational Resources Information Center

    American Psychologist, 2012

    2012-01-01

    Presents a short biography of the winner of the American Psychological Association's Award for Distinguished Contributions to Research in Public Policy. The 2012 winner is Dan Olweus for his rigorous scientific research on bullying among children and youth and his early and tireless attention to its public policy implications. Dan Olweus's…

  4. Learning during Stressful Times

    ERIC Educational Resources Information Center

    Shors, Tracey J.

    2004-01-01

    Stressful life events can have profound effects on our cognitive and motor abilities, from those that could be construed as adaptive to those not so. In this review, I discuss the general notion that acute stressful experience necessarily impairs our abilities to learn and remember. The effects of stress on operant conditioning, that is, learned…

  5. Dealing with Stress.

    ERIC Educational Resources Information Center

    Murphy, Linda; Della Corte, Suzanne

    1987-01-01

    This issue examines the causes and effects of stress among parents of handicapped children and offers guidance for reducing and/or avoiding stress. The factors contributing to parental stress are identified, including unfounded guilt feelings, prolonged dependency of the handicapped child, extended care requirements, marital discord and family…

  6. Organizational Stress among Teachers.

    ERIC Educational Resources Information Center

    Triesen, David; Williams, Mary-Jo

    1985-01-01

    This study was designed to determine Canadian teachers' perceptions of work related stress and to assess the degree to which these stressors accounted for overall job stress. Results indicated the factors which most contributed to overall job stress were role overload, relationships with students, work load, and relationships with colleagues.…

  7. Stress, Hyperreactivity, and Health.

    ERIC Educational Resources Information Center

    Plowman, Sharon Ann

    1994-01-01

    Researchers have not yet agreed upon links between stress and illness. Levels of response mediated by the central nervous system are considered important in predicting and determining health consequences of stress. The paper uses the cardiovascular system to examine experimental evidence for the relationship between stress, health/illness, and…

  8. Programmable calculator stress analysis

    SciTech Connect

    Van Gulick, L.A.

    1983-01-01

    Advanced programmable alphanumeric calculators are well suited for closed-form calculation of pressure-vessel stresses. They offer adequate computing power, portability, special programming features, and simple interactive execution procedures. Representative programs that demonstrate calculator capabilities are presented. Problems treated are stress and strength calculations in thick-walled pressure vessels and the computation of stresses near head/pressure-vessel junctures.

  9. MALDI-MS analysis and imaging of small molecule metabolites with 1,5-diaminonaphthalene (DAN)

    SciTech Connect

    Korte, Andrew R; Lee, Young Jin

    2014-07-08

    1,5-diaminonaphthalene (DAN) has previously been reported as an effective matrix for matrix-assisted laser desorption ionization-mass spectrometry of phospholipids. In the current work, we investigate the use of DAN as a matrix for small metabolite analysis in negative ion mode. DAN was found to provide superior ionization to the compared matrices for MW < ~400 Da; however, 9-aminoacridine (9-AA) was found to be superior for a uridine diphosphate standard (MW 566 Da). DAN was also found to provide a more representative profile of a natural phospholipid mixture than 9-AA. Finally, DAN and 9-AA were applied for imaging of metabolites directly from corn leaf sections. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

  10. Blocage de Coulomb dans une boite quantique laterale contenant un faible nombre d'electrons

    NASA Astrophysics Data System (ADS)

    Gould, Charles

    Dans ce travail on utilise une nouvelle geometrie pour augmenter le controle sur le nombre d'electrons contenus dans une boite quantique laterale, et ainsi atteindre un regime de petit nombre d'electrons. Ces echantillons permettent une etude du blocage de Coulomb quand les electrons sont injectes a partir d'un gaz electronique a deux dimensions (2DEG). Les mesures a faible champ magnetique demontrent la grande flexibilite des echantillons et montrent que l'on peut faire varier le nombre d'electrons dans une boite quantique a partir de plus de 40 electrons jusqu'a un seul electron, ce qui est assez courant dans les boites quantiques verticales, mais ce qui n'avait jamais ete reussi dans une boite quantique laterale. Nos resultats montrent egalement que dans les boites quantiques laterales il est possible de determiner le spin du niveau qui participe au transport a l'aide du phenomene de blocage de spin. De plus, dans certaines circonstances il est meme possible de determiner le spin total de la boite quantique, ce qui peut avoir des applications pratiques dans des domaines tels l'informatique quantique. Les mesures dans le regime de renversement de spin a un champ magnetique plus eleve montrent l'importance des correlations electrons---electrons dans ces boites quantiques, qui menent a des depolarisations et a des structures de spins qui ont un effet sur le transport. En particulier, ces correlations menent a l'existence de niveaux excites de basse energie qui causent une dependance anormale de l'amplitude des pics de blocage de Coulomb en fonction de la temperature. Nos experiences demontrent egalement la possibilite d'utiliser ces boites quantiques comme sondes pour etudier les proprietes du bord d'un 2DEG. Une voie de recherche a etre exploree.

  11. Stress Reactivity in Insomnia.

    PubMed

    Gehrman, Philip R; Hall, Martica; Barilla, Holly; Buysse, Daniel; Perlis, Michael; Gooneratne, Nalaka; Ross, Richard J

    2016-01-01

    This study examined whether individuals with primary insomnia (PI) are more reactive to stress than good sleepers (GS). PI and GS (n = 20 per group), matched on gender and age, completed three nights of polysomnography. On the stress night, participants received a mild electric shock and were told they could receive additional shocks during the night. Saliva samples were obtained for analysis of cortisol and alpha amylase along with self-report and visual analog scales (VAS). There was very little evidence of increased stress on the stress night, compared to the baseline night. There was also no evidence of greater stress reactivity in the PI group for any sleep or for salivary measures. In the GS group, stress reactivity measured by VAS scales was positively associated with an increase in sleep latency in the experimental night on exploratory analyses. Individuals with PI did not show greater stress reactivity compared to GS. PMID:25126695

  12. Stress impacts telomere dynamics.

    PubMed

    Kotrschal, Alexander; Ilmonen, Petteri; Penn, Dustin J

    2007-04-22

    Telomeres are DNA-protein complexes at the ends of chromosomes that control genomic integrity but appear to become shorter with age and stress. To test whether stress causes telomere attrition, we exposed the offspring of wild-caught house mice (Mus musculus) to stressful conditions and examined the changes in telomere length over six months. We found that females exposed to males and reproductive stress (either with or without crowding) had significantly shorter telomeres than controls, and males exposed to crowding stress had shorter telomeres than males that were not crowded. Our results indicate that stress alters telomere dynamics, causing attrition and hindering restoration, and these effects are sex dependent. Telomeres may thus provide a biomarker for assessing an individual's cumulative exposure or ability to cope with stressful conditions. PMID:17264051

  13. NASA Administrator Dan Goldin greets 10-year-old VIP.

    NASA Technical Reports Server (NTRS)

    2000-01-01

    NASA Administrator Dan Goldin (left) shares a light moment during his meeting with 10-year-old Jonathan Pierce (right), who is garbed in a protective cooling suit designed by NASA. Behind Goldin is astronaut Doug Wheelock; behind Jonathan is his mother, Penny. Jonathan suffers from erythropoietic protoporphyria, a rare condition that makes his body unable to withstand ultraviolet rays. The suit allows him to be outside during the day, which would otherwise be impossible. Jonathan's trip was funded by the Make-A-Wish Foundation and included a visit to Disney World. He and his family were among a dozen VIPs at KSC to view the launch of STS-99.

  14. Stress Management and Gifted Children

    ERIC Educational Resources Information Center

    Patel, Vidisha A.

    2009-01-01

    Stress can affect anyone, and gifted children are no exception. Giftedness can sometimes be the cause of the stress. Perfectionism, sensitivity, and intensity are characteristics of gifted children that may exacerbate stress. Stress can be constructive. Prolonged stress, however, with no time to recover becomes detrimental. Continued stress upsets…

  15. Stress Literacy in Australian Adolescents

    ERIC Educational Resources Information Center

    Varlow, Megan; Wuthrich, Viviana; Murrihy, Rachael; Remond, Louise; Tuqiri, Rebekka; van Kessel, Jacobine; Wheatley, Anna; Dedousis-Wallace, Anna; Kidman, Antony

    2009-01-01

    Stress literacy is a term that refers to knowledge about stress and stress management techniques. Levels of stress literacy were examined in more than nine hundred Australian adolescents by providing a short stress-management education session and assessing stress literacy using a pre-post survey design. It was found that while adolescents had a…

  16. Interoception and stress

    PubMed Central

    Schulz, André; Vögele, Claus

    2015-01-01

    Afferent neural signals are continuously transmitted from visceral organs to the brain. Interoception refers to the processing of visceral-afferent neural signals by the central nervous system, which can finally result in the conscious perception of bodily processes. Interoception can, therefore, be described as a prominent example of information processing on the ascending branch of the brain–body axis. Stress responses involve a complex neuro-behavioral cascade, which is elicited when the organism is confronted with a potentially harmful stimulus. As this stress cascade comprises a range of neural and endocrine pathways, stress can be conceptualized as a communication process on the descending branch of the brain–body axis. Interoception and stress are, therefore, associated via the bi-directional transmission of information on the brain–body axis. It could be argued that excessive and/or enduring activation (e.g., by acute or chronic stress) of neural circuits, which are responsible for successful communication on the brain–body axis, induces malfunction and dysregulation of these information processes. As a consequence, interoceptive signal processing may be altered, resulting in physical symptoms contributing to the development and/or maintenance of body-related mental disorders, which are associated with stress. In the current paper, we summarize findings on psychobiological processes underlying acute and chronic stress and their interaction with interoception. While focusing on the role of the physiological stress axes (hypothalamic-pituitary-adrenocortical axis and autonomic nervous system), psychological factors in acute and chronic stress are also discussed. We propose a positive feedback model involving stress (in particular early life or chronic stress, as well as major adverse events), the dysregulation of physiological stress axes, altered perception of bodily sensations, and the generation of physical symptoms, which may in turn facilitate

  17. General stress response signaling

    PubMed Central

    Huo, Yi-Xin; Rosenthal, Adam Z.; Gralla, Jay D.

    2008-01-01

    E. coli responds to stress by a combination of specific and general transcription signaling pathways. The general pathways typically require the master stress regulator sigma38 (rpoS). Here we show that the signaling from multiple stresses that relax DNA is processed by a non-conserved 8 amino acid tail of the sigma 38 C-terminal domain (CTD). By contrast, responses to stresses that accumulate potassium glutamate do not rely on this short tail, but still require the overall CTD. In vitro transcription and footprinting studies suggest that multiple stresses can target a poised RNA polymerase and activate it by unwrapping DNA from a nucleosome-like state, allowing the RNA polymerase to escape into productive mode. This transition can be accomplished by either the DNA relaxation or potassium glutamate accumulation that characterizes many stresses. PMID:18761624

  18. Luminescent nanocrystal stress gauge

    PubMed Central

    Choi, Charina L.; Koski, Kristie J.; Olson, Andrew C. K.; Alivisatos, A. Paul

    2010-01-01

    Microscale mechanical forces can determine important outcomes ranging from the site of material fracture to stem cell fate. However, local stresses in a vast majority of systems cannot be measured due to the limitations of current techniques. In this work, we present the design and implementation of the CdSe-CdS core-shell tetrapod nanocrystal, a local stress sensor with bright luminescence readout. We calibrate the tetrapod luminescence response to stress and use the luminescence signal to report the spatial distribution of local stresses in single polyester fibers under uniaxial strain. The bright stress-dependent emission of the tetrapod, its nanoscale size, and its colloidal nature provide a unique tool that may be incorporated into a variety of micromechanical systems including materials and biological samples to quantify local stresses with high spatial resolution. PMID:21098301

  19. Working women and stress.

    PubMed

    Swanson, N G

    2000-01-01

    Occupational stress is a growing problem in US workplaces and may be a problem of particular magnitude for working women, in part because of sex-specific job stressors (sex discrimination and difficulties combining work and family). Although such stressors have received little research attention until recent years, new research indicates that these stressors may have a negative impact on health and well-being above and beyond the effects of general job stressors (work overload, skill underutilization, etc). A number of stress-reduction strategies have been shown to be useful for working women, ranging from the more common individual stress management techniques to higher-level interventions focused on removing the sources of occupational stress. This article provides a brief overview of occupational stress as it affects working women and presents research on approaches for reducing the negative effects of job stress. PMID:10808656

  20. Stress Measurement System

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Under the Aircraft Structural Integrity program, Langley Research Center and Stress Photonics developed an infrared-based stress measurement system for use in nondestructive evaluation of materials and structures. Stress Photonics commercialized the technology in the DeltaTherm 1000 system, used to compare designs and detect cracks in structures, especially for aging aircraft and bridges. The system combines digital signal processing technology with a special infrared camera to provide instantaneous thermal images and live differential images.

  1. Stress and stem cells.

    PubMed

    Tower, John

    2012-01-01

    The unique properties and functions of stem cells make them particularly susceptible to stresses and also lead to their regulation by stress. Stem cell division must respond to the demand to replenish cells during normal tissue turnover as well as in response to damage. Oxidative stress, mechanical stress, growth factors, and cytokines signal stem cell division and differentiation. Many of the conserved pathways regulating stem cell self-renewal and differentiation are also stress-response pathways. The long life span and division potential of stem cells create a propensity for transformation (cancer) and specific stress responses such as apoptosis and senescence act as antitumor mechanisms. Quiescence regulated by CDK inhibitors and a hypoxic niche regulated by FOXO transcription factor function to reduce stress for several types of stem cells to facilitate long-term maintenance. Aging is a particularly relevant stress for stem cells, because repeated demands on stem cell function over the life span can have cumulative cell-autonomous effects including epigenetic dysregulation, mutations, and telomere erosion. In addition, aging of the organism impairs function of the stem cell niche and systemic signals, including chronic inflammation and oxidative stress. PMID:23799624

  2. Stress studies in EFG

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A computer code which can account for plastic deformation effects on stress generated in silicon sheet grown at high speeds is fully operative. Stress and strain rate distributions are presented for two different sheet temperature profiles. The calculations show that residual stress levels are very sensitive to details of the cooling profile in a sheet with creep. Experimental work has been started in several areas to improve understanding of ribbon temperature profiles and stress distributions associated with a 10 cm wide ribbon cartridge system.

  3. Osmoregulation and antioxidant production in maize under combined cadmium and arsenic stress.

    PubMed

    Anjum, Shakeel Ahmad; Tanveer, Mohsin; Hussain, Saddam; Shahzad, Babar; Ashraf, Umair; Fahad, Shah; Hassan, Waseem; Jan, Saad; Khan, Imran; Saleem, Muhammad Farrukh; Bajwa, Ali Ahsan; Wang, Longchang; Mahmood, Aqib; Samad, Rana Abdul; Tung, Shahbaz Atta

    2016-06-01

    An investigation was carried out to examine the combined and individual effects of cadmium (Cd) and arsenic (As) stress on osmolyte accumulation, antioxidant activities, and reactive oxygen species (ROS) production at different growth stages (45, 60, 75, 90 days after sowing (DAS)) of two maize cultivars viz., Dong Dan 80 and Run Nong 35. The Cd (100 μM) and As (200 μM) were applied separately as well as in combination (Cd + As) at 30 DAS. Results revealed pronounced variations in the behavior of antioxidants, osmolytes, and ROS in both maize cultivars under the influence of Cd and As stress. Activities of enzymatic (SOD, POD, CAT and APX, GPX, GR) and non-enzymatic (GSH and AsA) antioxidants, generation of ROS, and accumulation of osmolytes were enhanced with the passage of time; therefore, the maximum values for these attributes were observed at 90 DAS for both cultivars. Exposure of plants to Cd or As stress considerably enhanced the antioxidant activities, ROS, and osmolyte accumulation compared with control, while combined application of Cd + As was more devastating in reducing plant biomass of both maize cultivars. Among cultivars, Dong Dan 80 was better able to negate the heavy metal-induced oxidative damage, which was associated with higher antioxidant activities, greater osmolytes accumulation, and lower ROS production in this cultivar. PMID:26957429

  4. Transition de phase quantique de type verrouillage-deverrouillage dans les canaux lineaires coherents des phases en rayures dans les doubles puits quantiques sous champ magnetique perpendiculaire

    NASA Astrophysics Data System (ADS)

    Faribault, Alexandre

    On peut creer un gaz electronique bidimensionnel en utilisant le potentiel de confinement d'une couche mince d'un semiconducteur dans un substrat fait d'une autre semiconducteur de gap plus eleve. L'ajout d'un champ magnetique perpendiculaire au plan de confinement modifie de facon drastique les proprietes du gaz electronique. Pour des densites et des valeurs du champ magnetique adequatement choisies, on obtient un etat fondamental en onde de densite de charge. Dans un systeme compose de deux de ces gaz bidimensionnels suffisamment rapproches l'un de l'autre, on prevoit theoriquement l'existence d'un etat fondamental compose d'une onde de densite de charge dans chacun des puits et d'une serie de regions lineaires ou l'on a une delocalisation coherente des electrons entre les deux puits. Dans cette these, on etudie le comportement a temperature nulle de cet etat fondamental en rayures coherentes. L'etude numerique des modes collectifs de ces phases laisse croire qu'un deverrouillage des canaux coherents est envisageable dans ce systeme. Afin d'etudier cette possibilite, nous construisons d'abord un modele effectif de canaux quasi-unidimensionnels couples qui permettent de reproduire correctement les excitations collectives a basse energie de la phase en rayures coherentes du double puits quantique. Dans un systeme de coordonnees adequatement choisi, ces excitations peuvent etre decrites par des ondes de pseudospin. Les parametres de ce modele effectif simple peuvent etre extraits des calculs des fonctions de reponse realises dans l'approximation Hartree-Fock dependante du temps (appelee aussi Generalized Random Phase Approximation). On constate l'efficacite de ce modele a decrire la dynamique basse energie du systeme pour une certaine plage de distances inter-puits. En retirant de ce modele les contributions a l'hamiltonien provenant des couplages de type Josephson entre les canaux, on obtient alors un systeme ou les canaux sont deverrouilles. Un traitement en

  5. Stress urinary incontinence.

    PubMed

    Nygaard, Ingrid E; Heit, Michael

    2004-09-01

    Stress urinary incontinence, the complaint of involuntary leakage during effort or exertion, occurs at least weekly in one third of adult women. The basic evaluation of women with stress urinary incontinence includes a history, physical examination, cough stress test, voiding diary, postvoid residual urine volume, and urinalysis. Formal urodynamics testing may help guide clinical care, but whether urodynamics improves or predicts the outcome of incontinence treatment is not yet clear. The distinction between urodynamic stress incontinence associated with hypermobility and urodynamic stress incontinence associated with intrinsic sphincter deficiency should be viewed as a continuum, rather than a dichotomy, of urethral function. Initial treatment should include behavioral changes and pelvic floor muscle training. Estrogen is not indicated to treat stress urinary incontinence. Bladder training, vaginal devices, and urethral inserts also may reduce stress incontinence. Bulking agents reduce leakage, but effectiveness generally decreases after 1-2 years. Surgical procedures are more likely to cure stress urinary incontinence than nonsurgical procedures but are associated with more adverse events. Based on available evidence at this time, colposuspension (such as Burch) and pubovaginal sling (including the newer midurethral synthetic slings) are the most effective surgical treatments. PMID:15339776

  6. The stressed heart

    SciTech Connect

    Legato, M.J. )

    1987-01-01

    This book contains 16 papers. Some of the titles are: Regulation of gene expression in the normal and overloaded heart; Cell stress and the initiation of growth; Subcellular growth of cardiocytes during hypertrophy; Microcirculation is the stressed heart; and The biochemistry of myocardial failure.

  7. Dealing with Stress.

    ERIC Educational Resources Information Center

    Here's How, 1983

    1983-01-01

    One of a series of practitioner-oriented newsletters, the document provides elementary school principals with tips for dealing with stress. Because principals spend approximately 80 percent of their workday in face-to-face interchanges (with staff, faculty, parents, and others), the article gives warning signals indicative of too much stress. A…

  8. Foster Parent Stress.

    ERIC Educational Resources Information Center

    Jones, Graham; Morrissette, Patrick J.

    1999-01-01

    Research findings regarding foster-parent stress and implications for counselors and counselor educators are discussed. Eleven significant themes are reported from a qualitative and quantitative study of rural foster parents (N=156). Stressful events that affect the well-being of foster parents and their relationships with children and…

  9. Stress detection in plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    How can the status of plant stress be measured rapidly and accurately in the hundreds of trees managed within a commercial orchard? Two technologies have been developed over the past two decades that will provide useful information to detect plant stress in orchard systems: 1) Reflectance of visibl...

  10. Keeping Fit: Stress Relievers

    ERIC Educational Resources Information Center

    Crupi, Jeffrey

    2005-01-01

    With all the extra demands that are placed on teachers during the months of May and June, the end of the year can be an extremely stressful time. This article describes several tips for diminishing the effects of end of year stress. The following relaxation tips are described: (1) Neck and Upper Shoulder Stretch; (2) Superman Stretch; (3) Doorway…

  11. Steps To Beat Stress.

    ERIC Educational Resources Information Center

    Shelton, Michael

    1998-01-01

    Explains techniques for reducing stress: diaphragmatic breathing, relaxation, progressive muscle relaxation, and meditation. Two sidebars define the fight-or-flight response and the camp administration's role in helping to lower stress through staff training and reduction of camp-wide stressors. (SAS)

  12. Correlates of School Stress.

    ERIC Educational Resources Information Center

    Matthews, Doris B.

    As part of a continuing series of research studies on stress in schools, this study examined the construct validity of peripheral temperature at the fingertips as a measure of school stress. Measurements were made in classes selected at random from 11 volunteer schools in South Carolina. Three types of correlational studies were undertaken: (1)…

  13. Relaxation techniques for stress

    MedlinePlus

    ... Know. February 2013. Available at: nccih.nih.gov/health/stress/relaxation.htm . Accessed September 21, 2015. National Center ... A.D.A.M. Editorial team. Related MedlinePlus Health Topics Stress Browse the Encyclopedia A.D.A.M., Inc. ...

  14. Risk/Stress Analysis.

    ERIC Educational Resources Information Center

    Schwerdtfeger, Don; Howell, Richard E.

    1986-01-01

    Identifies stress as a definite health hazard and risk factor involved in a variety of health situations. Proposes that stress identification efforts be considered in environmental analysis so that a more complete approach to risk assessment and management and health hazard prevention can occur. (ML)

  15. Stress in Fish

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stress in fish involves a condition disruptive of physiological homeostasis that occurs in response to unfavorable external influences and is capable of adversely affecting fish. Any stimulus that provokes stress responses is known as a stressor, disrupting a stable condition and causing a response....

  16. Release from Stress.

    ERIC Educational Resources Information Center

    Gmelch, Walter H.

    An overview of the most recent ideas on managerial stress is presented along with worksheets and exercises for a program to help educational administrators, their staffs, and secretaries cope with and reduce organizational and personal stress. Research cited includes the author's survey of 1,200 Oregon school administrators and over 200…

  17. Stress Management for Sport.

    ERIC Educational Resources Information Center

    Zaichkowsky, Leonard D., Ed.; Sime, Wesley E., Ed.

    Included in this volume are papers on stress management in athletics; eight of the ten papers are followed with a "Coach's Reaction": (1) "Competitive Athletic Stress Factors in Athletes and Coaches" (Walter Kroll); (2) "Mental Preparation for Peak Performance in Swimmers" (Eugene F. Gauron)--Coach's Reaction by Suzi D'Annolfo; (3) "Cognitive…

  18. Stress and Your Brain

    MedlinePlus

    ... weakness to stress. "The fact that we could increase these animals' ability to adapt to stress by blocking BDNF and its signals means that it may be possible to develop compounds that improve ... how to increase resistance in situations that might otherwise result in ...

  19. Stress studies in EFG

    NASA Technical Reports Server (NTRS)

    1982-01-01

    A program to study stress generation mechanisms in silicon sheet growth was started. The purpose of the research is to define post-growth temperature profiles for the sheet that can minimize its stress during growth at high speeds, e.g., greater than 3 cm/min. The initial tasks described concern work in progress toward the development of computing capabilities to (1) model stress-temperature relationships in steady-state ribbon growth, and (2) provide a means to calculate realistic temperature fields in ribbon, given growth system component temperatures as boundary conditions. If it is determined that low stress configurations can be achieved, the modeling is to be tested experimentally by constructing low-stress growth systems for EFG silicon ribbon.

  20. Stress on the College Campus.

    ERIC Educational Resources Information Center

    Gill, Wanda E.

    A Stress Test designed to help college students increase awareness of stress and ways they deal with it is presented, along with suggestions to reduce stress. The stress test was presented at a workshop by George Washington University graduate students. The test's four scales measure ways that students cope with stress and the student's…

  1. Structure of Protein Related to DAN and Cerberus (PRDC): Insights into the Mechanism of BMP Antagonism

    PubMed Central

    Nolan, Kristof; Kattamuri, Chandramohan; Luedeke, David M.; Deng, Andy; Jagpal, Amrita; Zhang, Fuming; Linhardt, Robert; Kenny, Alan P.; Zorn, Aaron M.; Thompson, Thomas B.

    2013-01-01

    Summary The Bone Morphogenetic Proteins (BMP) are secreted ligands largely known for their functional roles in embryogenesis and tissue development. A number of structurally diverse extracellular antagonists inhibit BMP ligands to regulate signaling. The DAN family of antagonists represents the largest group of BMP inhibitors, however, little is known for how they mechanistically inhibit BMP ligands. Here, we present the structure of the DAN family member Protein Related to Dan and Cerberus (PRDC) solved by X-ray crystallography. The structure reveals an unexpected growth factor-like appearance with a novel dimerization mechanism that is formed through extensive β-strand contacts. Using site-directed mutagenesis coupled with in vitro and in vivo activity assays, we identified a BMP binding epitope on PRDC. We also determined that PRDC binds heparin with high affinity and that heparin binding to PRDC interferes with BMP antagonism. These results offer insight for how DAN family antagonists functionally inhibit BMP ligands. PMID:23850456

  2. Feeling Stressed? Stress Relief Might Help Your Health

    MedlinePlus

    ... new tasks if they are putting you into overload. Think positive. Note what you’ve accomplished at ... TALK (1-800-273-8255). Stress: NIH Health Information Fact Sheet on Stress Psychological Stress and Cancer ...

  3. Tuberculome de Bouchut dans la tuberculose multi focale: à propos de quatre cas

    PubMed Central

    Janah, Hicham; Alami, Ahmed; Souhi, Hicham; Zegmout, Adil; Naji-Amrani, Hicham; Raoufi, Mohamed; Elouazzani, Hanane; Rhorfi, Ismail Abderrahmani; Abid, Ahmed

    2014-01-01

    La tuberculose multifocale a connu un regain de fréquence avec la pandémie du SIDA, elle s'observe encore chez des sujets non infectés par le VIH surtout dans les pays en voie de développement notamment au Maroc. Nous rapportons quatre observations de tuberculose multifocale chez trois patients immunocompétents et un patient immunodéprimé. Quatre patients ont bénéficié d'un bilan phtisiologique, biologique, sérologique(HIV), radiologique et d'angiographie à la fluorescéine pour suspicion de tuberculose multifocale. Il s'agit de trois hommes et une femme, d’âge moyen de 44 ans, trois patients sont immunocompétents et un patient séropositif. La tuberculose intéressait trois localisations chez les quatre patients: pulmonaire dans quatre cas, ophtalmique dans quatre cas, digestive dans un cas, urinaire dans un cas, cérébrale dans un cas et un cas d'atteinte de la moelle osseuse. L'atteinte ophtalmologique est représentée par des nodules choroïdiens de Bouchut dans quatre cas et un nodule papillaire de Bouchut dans un cas; aucun des ces patients ne présentait une uvéite granulomateuse. Nos malades ont reçu un traitement anti-tuberculeux d'une durée de neuf mois avec une bonne évolution clinique, biologique, radiologique et angiographique. Au Maroc, la tuberculose continue à surprendre aussi bien par son extension touchant le sujet débilité et le sujet immunocompétent, que par ses présentations diverses y compris l'atteinte oculaire qu'elle faut rechercher par un examen ophtalmologique soigneux et systématique. PMID:25478047

  4. The Dynamic Albedo of Neutrons (DAN) experiment for NASA's 2009 Mars Science Laboratory.

    PubMed

    Litvak, M L; Mitrofanov, I G; Barmakov, Yu N; Behar, A; Bitulev, A; Bobrovnitsky, Yu; Bogolubov, E P; Boynton, W V; Bragin, S I; Churin, S; Grebennikov, A S; Konovalov, A; Kozyrev, A S; Kurdumov, I G; Krylov, A; Kuznetsov, Yu P; Malakhov, A V; Mokrousov, M I; Ryzhkov, V I; Sanin, A B; Shvetsov, V N; Smirnov, G A; Sholeninov, S; Timoshenko, G N; Tomilina, T M; Tuvakin, D V; Tretyakov, V I; Troshin, V S; Uvarov, V N; Varenikov, A; Vostrukhin, A

    2008-06-01

    We present a summary of the physical principles and design of the Dynamic Albedo of Neutrons (DAN) instrument onboard NASA's 2009 Mars Science Laboratory (MSL) mission. The DAN instrument will use the method of neutron-neutron activation analysis in a space application to study the abundance and depth distribution of water in the martian subsurface along the path of the MSL rover. PMID:18598140

  5. Stress and Alcohol

    PubMed Central

    Keyes, KM.; Hatzenbuehler, ML.; Grant, Bridget F.; Hasin, Deborah S.

    2012-01-01

    Exposure to stress often is psychologically distressing. The impact of stress on alcohol use and the risk of alcohol use disorders (AUDs) depends on the type, timing during the life course, duration, and severity of the stress experienced. Four important categories of stressors that can influence alcohol consumption are general life stress, catastrophic/fateful stress, childhood maltreatment, and minority stress. General life stressors, including divorce and job loss, increase the risk for AUDs. Exposure to terrorism or other disasters causes population-level increases in overall alcohol consumption but little increase in the incidence of AUDs. However, individuals with a history of AUDs are more likely to drink to cope with the traumatic event. Early onset of drinking in adolescence, as well as adult AUDs, are more common among people who experience childhood maltreatment. Finally, both perceptions and objective indicators of discrimination are associated with alcohol use and AUDs among racial/ethnic and sexual minorities. These observations demonstrate that exposure to stress in many forms is related to subsequent alcohol consumption and AUDs. However, many areas of this research remain to be studied, including greater attention to the role of various stressors in the course of AUDs and potential risk moderators when individuals are exposed to stressors. PMID:23584105

  6. [Osteoporosis and stress].

    PubMed

    Kumano, Hiroaki

    2005-09-01

    There may be three ways of relationship between stress and osteoporosis. The first is that stress induces some physiological changes leading to osteoporosis. The second is that stress induces behavioral distortion of eating, drinking, exercise, and sleep habits, which leads to osteoporosis. The third is that osteoporosis, on the other hand, brings about anxiety, depression, loss of social roles, and social isolation, which leads to stress. The susceptible sex and age groups are postmenopausal women and young women. The abrupt decrease of estrogen in postmenopausal women promotes reabsorption of bone, and it was also reported that the increase of interleukin-6 (IL-6) that is downstream of estrogen was related to the production of osteoclast and to the development of disability of the aged. Regarding the association with stress, while it was reported that depression or depressive states directly increased inflammation-induced cytokines including IL-6, it was also pointed out that stress-induced easy infectious may produce chronic infection, which indirectly increases inflammation-induced cytokines. Anorexia Nervosa that is assumed to be associated with adolescent developmental stress is noteworthy in young women. Amenorrhea is always present in this disease, and in addition to bone reabsorption associated with estrogen deficiency, the decrease of bone formation associated with malnutrition may be related to the development of osteoporosis. PMID:16137956

  7. Bolt Stress Monitor

    NASA Technical Reports Server (NTRS)

    1978-01-01

    In photo, an engineer is using a new Ultrasonic Bolt Stress Monitor developed by NASA's Langley Research Center to determine whether a bolt is properly tightened. A highly accurate device, the monitor is an important tool in construction of such structures as pressure vessels, bridges and power plants, wherein precise measurement of the stress on a tightened bolt is critical. Overtightened or undertightened bolts can fail and cause serious industrial accidents or costly equipment break-downs. There are a number of methods for measuring bolt stress. Most widely used and least costly is the torque wrench, which is inherently inaccurate; it does not take into account the friction between nut and bolt, which has an influence on stress. At the other end of the spectrum, there are accurate stress-measuring systems, but they are expensive and not portable. The battery-powered Langley monitor fills a need; it is inexpensive, lightweight, portable and extremely accurate because it is not subject to friction error. Sound waves are transmitted to the bolt and a return signal is received. As the bolt is tightened, it undergoes changes in resonance due to stress, in the manner that a violin string changes tone when it is tightened. The monitor measures the changes in resonance and provides a reading of real stress on the bolt. The device, patented by NASA, has aroused wide interest and a number of firms have applied for licenses to produce it for the commercial market.

  8. Assessment of Workplace Stress: Occupational Stress, Its Consequences, and Common Causes of Teacher Stress.

    ERIC Educational Resources Information Center

    Hansen, Jo-Ida; Sullivan, Brandon A.

    This chapter introduces teachers and other education professionals to the assessment of occupational stress. It begins with a brief discussion of what occupational stress is, and overview of the consequences of prolonged stress, and a review of the common causes of teacher stress. Next, it presents methods for reducing occupational stress through…

  9. Validating Measures of Teacher Stress.

    ERIC Educational Resources Information Center

    Pettegrew, Loyd S.; Wolf, Glenda E.

    1982-01-01

    A validation study in the development of empirical measures of teacher stress is presented. Role-related, task-based, and environmental stress measures demonstrated internal consistency and provided reliable and valid multivariate assessment of teacher stress. (PN)

  10. Stress-Detection Lenses

    NASA Technical Reports Server (NTRS)

    1996-01-01

    An Ames Research Center scientist invented an infrared lens used in sunglasses to filter out ultraviolet rays. This product finds its origins in research for military enemy detection. Through a Space Act Agreement, Optical Sales Corporation introduced the Hawkeye Lenses not only as sunglasses but as plant stress detection lenses. The lenses enhance the stressed part of the leaf, which has less chlorophyll than healthy leaves, through dyes that filter out certain wavelengths of light. Plant stress is visible earlier, at a stage when something can be done to save the plants.

  11. Le stress perçu: validation de la traduction d'une échelle de mesure de stress en dialecte marocain

    PubMed Central

    Loubir, Dalal Ben; Serhier, Zeineb; Otmani, Nada; Housbane, Samy; Mouddene, Naima Ait; Agoub, Mohamed; Othmani, Mohammed Bennani

    2015-01-01

    Introduction L'article a pour objectif de valider la traduction en dialecte arabe Marocain, de l’échelle du stress perçu « Perceived Stress Scale » chez un large échantillon de la population marocaine. Méthodes Une méthode de traduction et contre traduction en dialecte Marocain a été réalisée pour l’échelle « Perceived Stress Scale » à 10 items. Une étude de type transversale, a été menée par la suite en suivant un échantillonnage par quotas qui a ciblé les individus âgés de plus de 18 ans et appartenant à différentes catégories sociales. Les participants ont répondus aux versions marocaines de l’échelle « Perceived Stress Scale » et d'une version réduite de l’échelle « The Survey of Recent Life Experience ». La validation des qualités métrologiques a été établie en examinant: la fiabilité interne, la fiabilité test-retest, la validité convergente et la structure factorielle. Résultats Cinq cent trente-cinq participants ont répondu aux questionnaires. La version marocaine de l’échelle « Perceived Stress Scale » a présenté une bonne fiabilité interne (α = 0,80) et fiabilité test-retest (CCI= 0,87). D'autant plus, l'analyse en composante principale de l’échelle « Perceived Stress Scale » a permis d'extraire deux facteurs qui ont permis d'expliquer 53,4% de la variance totale. Les deux échelles utilisées étaient assez bien corrélées (r = 0,467, p < 0,01). Conclusion La présente étude a permis d'obtenir une version marocaine de l’échelle « Perceived Stress Scale » avec des propriétés psychométriques satisfaisantes, dont l'utilisation sera d'une grande aide dans la pratique médicale, aussi bien que dans la réalisation des études de recherche qui s'intéressent au stress psychologique. PMID:26587130

  12. Wrinkle reduction in post-menopausal women consuming a novel oral supplement: a double-blind placebo-controlled randomized study

    PubMed Central

    Jenkins, G; Wainwright, L J; Holland, R; Barrett, K E; Casey, J

    2014-01-01

    Synopsis Objective The maintenance of youthful skin appearance is strongly desired by a large proportion of the world's population. The aim of the present study was therefore to evaluate the effect on skin wrinkling, of a combination of ingredients reported to influence key factors involved in skin ageing, namely inflammation, collagen synthesis and oxidative/UV stress. A supplemented drink was developed containing soy isoflavones, lycopene, vitamin C and vitamin E and given to post-menopausal women with a capsule containing fish oil. Method We have performed a double-blind randomized controlled human clinical study to assess whether this cocktail of dietary ingredients can significantly improve the appearance of facial wrinkles. Results We have shown that this unique combination of micronutrients can significantly reduce the depth of facial wrinkles and that this improvement is associated with increased deposition of new collagen fibres in the dermis. Conclusion This study demonstrates that consumption of a mixture of soy isoflavones, lycopene, vitamin C, vitamin E and fish oil is able to induce a clinically measureable improvement in the depth of facial wrinkles following long-term use. We have also shown, for the first time with an oral product, that the improvement is associated with increased deposition of new collagen fibres in the dermis. Résumé Objectif Le maintien de l'apparence d'une peau jeune est vivement souhaité par une grande proportion de la population mondiale. L'objectif de la présente étude était donc d'évaluer l'effet sur les rides de la peau, d'une combinaison d'ingrédients rapportés à influer sur les facteurs clés impliqués dans le vieillissement de la peau, à savoir l'inflammation, la synthèse du collagène et le stress oxydatif / UV. Une boisson supplémentée a été élaborée contenant des isoflavones de soja, le lycopène, la vitamine C et la vitamine E et donnée aux femmes ménopausées avec une capsule contenant de l

  13. Stress urinary incontinence

    MedlinePlus

    ... you urinate. Urinalysis to check for urinary tract infection. Urinary stress test: You stand with a full bladder ... out of the bed or chair Unpleasant odors Urinary tract infections Vaginal discharge The condition may get in the ...

  14. Let's Stress Chemistry.

    ERIC Educational Resources Information Center

    Webb, Michael J.; And Others

    1983-01-01

    Two descriptive chemistry experiments are presented which foster development of students' skills in making observations and deductions. In addition, the experiments are designed to stress the importance of chemical behavior and clear presentation of experimental findings. (JN)

  15. Measuring Environmental Stress

    ERIC Educational Resources Information Center

    Walker, John E.; Dahm, Douglas B.

    1975-01-01

    Infrared remote sensors, plus photometric interpretation and digital data analysis are being used to record the stresses on air, water, vegetation and soil. Directly recorded photographic information has been the most effective recording media for remote sensing. (BT)

  16. On Landing Gear Stresses

    NASA Technical Reports Server (NTRS)

    Gentric, A.

    1956-01-01

    Information on landing gear stresses is presented on the following: vibratory phenomena, tangential forces applied to landing gear, fore and aft oscillations of landing gears, examples of fatigue failures, vibration calculations, and improvement of existing test equipment.

  17. Environmental Stress Screening 2000

    NASA Technical Reports Server (NTRS)

    Gibbel, Mark

    1997-01-01

    The following identifies the authors of this report and the organizations that sponsored the effort conducted under the National Center for Manufacturing Sciences (NCMS) Environmental Stress Screening (ESS) 2000 Project.

  18. Voice stress analysis

    NASA Technical Reports Server (NTRS)

    Brenner, Malcolm; Shipp, Thomas

    1988-01-01

    In a study of the validity of eight candidate voice measures (fundamental frequency, amplitude, speech rate, frequency jitter, amplitude shimmer, Psychological Stress Evaluator scores, energy distribution, and the derived measure of the above measures) for determining psychological stress, 17 males age 21 to 35 were subjected to a tracking task on a microcomputer CRT while parameters of vocal production as well as heart rate were measured. Findings confirm those of earlier studies that increases in fundamental frequency, amplitude, and speech rate are found in speakers involved in extreme levels of stress. In addition, it was found that the same changes appear to occur in a regular fashion within a more subtle level of stress that may be characteristic, for example, of routine flying situations. None of the individual speech measures performed as robustly as did heart rate.

  19. enceladus_stress_map

    NASA Video Gallery

    This is a map of the changing stress on the surface of Enceladus' icy crust from the wobble and gravitational tides. Blue lines show the direction of forces pulling the crust apart, and red lines s...

  20. Posttraumatic Stress Disorder

    MedlinePlus

    ... stressful events or learn about an unexpected or violent death or injury to a family member or ... should. Traumatic events that can cause PTSD include: violent assaults, including rape fire physical or sexual abuse ...

  1. An Overview of Stress, Career Burnout, Student Stress and Stress Management.

    ERIC Educational Resources Information Center

    Journal of School Health, 1981

    1981-01-01

    Three articles presented at the 54th Annual Convention of the American School Health Association discuss: understanding stress with an emphasis on environmental factors; stress management techniques; and questions from the audience pertaining to stress management. (JN)

  2. Stress and heat flow

    SciTech Connect

    Lachenbrunch, A.H.; McGarr, A.

    1990-01-01

    As the Pacific plate slides northward past the North American plate along the San Andreas fault, the frictional stress that resists plate motion there is overcome to cause earthquakes. However, the frictional heating predicted for the process has never been detected. Thus, in spite of its importance to an understanding of both plate motion and earthquakes, the size of this frictional stress is still uncertain, even in order of magnitude.

  3. Les fluctuations supraconductrices dans le compose praseodyme-cerium-oxyde de cuivre

    NASA Astrophysics Data System (ADS)

    Renaud, Jacques

    Ce travail etudie les fluctuations supraconductrices dans le compose supraconducteur a haute temperature critique dope aux electrons Pr2-xCe xCuO4+delta. La technique utilisee pour sonder ces fluctuations est le transport electrique DC dans le plan ab. Il s'agit, a notre connaissance, de la premiere etude de ce type dans la classe generale des supraconducteurs a haute temperature critique dopes aux electrons et, plus particulierement, dans Pr2-xCe xCuO4+delta. De plus, l'etude est effectuee pour trois regimes de dopage, soit sous-dope x = 0.135, dopage optimal x = 0.15 et surdope x = 0.17. Les echantillons etudies sont des couches minces d'epaisseur plus grande que 100 nm crues par ablation laser. Les mesures electriques DC effectuees dans ce travail sont la resistance en reponse lineaire et les courbes IV en reponse non lineaire en fonction de la temperature. La mise en oeuvre experimentale de ces mesures a necessite une grande attention au filtrage et aux effets de chauffage a haut courant. Nous montrons que, sans cette attention, les donnees experimentales sont toujours erronees dans le regime pertinent pour nos echantillons. Les resultats pour le dopage optimal x = 0.15 sont expliques de facon tres convaincante dans le cadre de fluctuations purement 2D. D'abord, le regime des fluctuations gaussiennes est tres bien decrit par le modele d'Aslamazov-Larkin en deux dimensions. Ensuite, le regime de fluctuations critiques, se trouvant a plus basse temperature que le regime gaussien, est tres bien decrit par la physique 2D de Kosterlitz-Thouless. Dans cette analyse, les deux regimes ont des temperatures critiques coherentes entre elles, ce qui semble confirmer ce scenario 2D. Une analyse des donnees dans le cadre de fluctuations 3D est exploree mais donne des conclusions incoherentes. Les resultats pour les autres dopages sont qualitativement equivalents avec le dopage optimal et permettent donc une explication purement 2D. Par contre, contrairement au dopage optimal

  4. Stress studies in EFG

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Stress distributions were calculated for a creep law to predict a rate of plastic deformation. The expected reduction in stresses is obtained. Improved schemes for calculating growth system temperature distributions were evaluated. Temperature field modeling examined the possibility of using horizontal temperature gradients to influence stress distribution in ribbon. The defect structure of 10 cm wide ribbon grown in the cartridge system was examined. A new feature is identified from an examination of cross sectional micrographs. It consists of high density dislocation bands extending through the ribbon thickness. A four point bending apparatus was constructed for high temperature study of the creep response of silicon, to be used to generate defects for comparison with as grown defects in ribbon. The feasibility of laser interferometric techniques for sheet residual stress distribution measurement is examined. The mathematical formalism for calculating residual stress from changes in surface topology caused by an applied stress in a rectangular specimen was developed, and the system for laser interferometric measurement to obtain surface topology data was tested on CZ silicon.

  5. Dynamic Triggering Stress Modeling

    NASA Astrophysics Data System (ADS)

    Gonzalez-Huizar, H.; Velasco, A. A.

    2008-12-01

    It has been well established that static (permanent) stress changes can trigger nearby earthquakes, within a few fault lengths from the causative event, whereas triggering by dynamic (transient) stresses carried by seismic waves both nearby and at remote distances has not been as well documented nor understood. An analysis of the change in the local stress caused by the passing of surfaces waves is important for the understanding of this phenomenon. In this study, we modeled the change in the stress that the passing of Rayleigh and Loves waves causes on a fault plane of arbitrary orientation, and applied a Coulomb failure criteria to calculate the potential of these stress changes to trigger reverse, normal or strike-slip failure. We preliminarily test these model results with data from dynamically triggering earthquakes in the Australian Bowen Basin. In the Bowen region, the modeling predicts a maximum triggering potential for Rayleigh waves arriving perpendicularly to the strike of the reverse faults present in the region. The modeled potentials agree with our observations, and give us an understanding of the dynamic stress orientation needed to trigger different type of earthquakes.

  6. Overview of Stress Effects on Body and Stress Prevention Techniques.

    ERIC Educational Resources Information Center

    McManus, John L.

    Definitions of stress all imply that stress is a condition resulting from some change or imbalance that requires individual adjustment. When this does not occur, stress becomes an adverse condition which may eventually cause serious harm. Numerous studies have established the connection between unrelieved stress and adverse body reactions such as…

  7. Transitions de phase dans le oxyde de yttrium vanadium

    NASA Astrophysics Data System (ADS)

    Roberge, Benoit

    Dans le mémoire qui suit, les ordres structural, magnétiques et orbital dans le YVO3 sont étudiés avec l'aide de la diffraction des rayons X,de la spectroscopie Raman et de la technique de la cavité résonnante hyperfréquence. L'objectif premier consiste à observer l'évolution de ces ordres en fonction de la température. Le mémoire met ensuite en évidence le couplage entre les différents ordres cohabitants dans le YVO3 . Les mesures effectuées par la diffraction des rayons X permettent de mesurer le caractère polycrystallin des échantillons du YVO 3. Une comparaison de nos mesures avec des mesures de diffraction des rayons X faites sur la poudre de YVO3 indique la faible présence de maclage. Les mesures effectuées avec la technique de résonnance hyperfréquence permettent de suivre l'évolution de la constante diélectrique en fonction de la température. Les changements impliquant l'ordre orbital se manifestent de manière évidente dans la constante diélectrique à 200 K et à 77 K. La transition diélectrique détectée à 77 K est une transition de premier ordre. Un couplage entre les propriétés diélectriques et magnétiques est observable à la température de Néel à 114 K. L'effet d'un champ magnétique fixe sur la température de transition de l'ordre orbital survenant à 77 K est également remarquable. Cela indique un couplage magnétodiélectrique démontrant ainsi le caractère multiferroïque du YVO 3. Finalement, l'observation d'un mécanisme de relaxation pouvant être modélisé par le modèle d'Havriliak-Negami est observé en dessous de 77 K. En utilisant le modèle d'Arrhénius et le modèle d'Havriliak-Negami, on peut caractériser le mécanisme avec son énergie d'activation et son temps de relaxation. Les mesures effectuées en spectroscopie Raman permettent de suivre l'évolution de la structure du YVO3 en fonction de la température. Les deux changements structuraux survenant à 200 K et 77 K sont observés. Le

  8. Reconsidering Post-Traumatic Stress

    ERIC Educational Resources Information Center

    Berman, Dene S.; Davis-Berman, Jennifer

    2005-01-01

    This article serves to challenge the prevailing wisdom that suggests that most trauma is followed by post-traumatic stress disorder (PTSD), and is best treated with critical incident stress debriefing (CISD). Instead, recent evidence suggests that many individuals exposed to stress do not experience stress responses. Even those who do, however,…

  9. Modifiers and Perceived Stress Scale.

    ERIC Educational Resources Information Center

    Linn, Margaret W.

    1986-01-01

    The Modifiers and Perceived Stress Scale measures stressful life events by number and amount of perceived stresses and provides scores for variables such as anticipation of events, responsibility for events, and amount of social support from family and friends in coping with each event that modify the way stress is perceived. (Author)

  10. Piping stress handbook. Second edition

    SciTech Connect

    Helguero, V.

    1986-01-01

    This abridged volume contains the following: Coefficients of thermal expansion. Allowable stress range for ANSI/ASME Power Piping Code B31.1. Stress intensification and flexibility factors. Pressure and stress ratios. Design criteria for allowable loads, moment, and stresses. Properties of pipe. Weight and dimensions of pipe and components. Pipe support selection and design. Fundamentals of expansion joints. Index.

  11. Perceived Stress among Deaf Adults

    ERIC Educational Resources Information Center

    Jones, Elaine G.; Ouellette, Sue E.; Kang, Youngmi

    2006-01-01

    The Present Article describes the effectiveness of stress management classes in decreasing perceived stress among Deaf adults. Deaf adults may experience unique stressors, in addition to circumstances associated with increased stress in the general population. The Perceived Stress Scale (S. Cohen, Kamarck, & Mermelstein, 1983) was used as a…

  12. Educator Stress: Myth or Reality?

    ERIC Educational Resources Information Center

    Farkas, James P.; Milstein, Mike

    Although many researchers conclude that education is a profession marked by high levels of stress or experience of "burnout," this paper contends that educators are more adaptable and hence less stressed than the literature would indicate. The paper surveys literature on educator stress, presents studies indicating low educator stress, and…

  13. Staphylococcal response to oxidative stress

    PubMed Central

    Gaupp, Rosmarie; Ledala, Nagender; Somerville, Greg A.

    2012-01-01

    Staphylococci are a versatile genus of bacteria that are capable of causing acute and chronic infections in diverse host species. The success of staphylococci as pathogens is due in part to their ability to mitigate endogenous and exogenous oxidative and nitrosative stress. Endogenous oxidative stress is a consequence of life in an aerobic environment; whereas, exogenous oxidative and nitrosative stress are often due to the bacteria's interaction with host immune systems. To overcome the deleterious effects of oxidative and nitrosative stress, staphylococci have evolved protection, detoxification, and repair mechanisms that are controlled by a network of regulators. In this review, we summarize the cellular targets of oxidative stress, the mechanisms by which staphylococci sense oxidative stress and damage, oxidative stress protection and repair mechanisms, and regulation of the oxidative stress response. When possible, special attention is given to how the oxidative stress defense mechanisms help staphylococci control oxidative stress in the host. PMID:22919625

  14. [Complex posttraumatic stress disorder].

    PubMed

    Green, Tamar; Kotler, Moshe

    2007-11-01

    The characteristic symptoms resulting from exposure to an extreme trauma include three clusters of symptoms: persistent experience of the traumatic event, persistent avoidance of stimuli associated with the trauma and persistent symptoms of increased arousal. Beyond the accepted clusters of symptoms for posttraumatic stress disorder exists a formation of symptoms related to exposure to extreme or prolonged stress e.g. childhood abuse, physical violence, rape, and confinement within a concentration camp. With accumulated evidence of the existence of these symptoms began a trail to classify a more complex syndrome, which included, but was not confined to the symptoms of posttraumatic stress disorder. This review addresses several subjects for study in complex posttraumatic stress disorder, which is a complicated and controversial topic. Firstly, the concept of complex posttraumatic stress disorder is presented. Secondly, the professional literature relevant to this disturbance is reviewed and finally, the authors present the polemic being conducted between the researchers of posttraumatic disturbances regarding validity, reliability and the need for separate diagnosis for these symptoms. PMID:18087837

  15. Stress studies in EFG

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Experimental work in support of stress studies in high speed silicon sheet growth has been emphasized in this quarter. Creep experiments utilizing four-point bending have been made in the temperature range from 1000 C to 1360 C in CZ silicon as well as on EFG ribbon. A method to measure residual stress over large areas using laser interferometry to map strain distributions under load is under development. A fiber optics sensor to measure ribbon temperature profiles has been constructed and is being tested in a ribbon growth furnace environment. Stress and temperature field modeling work has been directed toward improving various aspects of the finite element computing schemes. Difficulties in computing stress distributions with a very high creep intensity and with non-zero interface stress have been encountered and additional development of the numerical schemes to cope with these problems is required. Temperature field modeling has been extended to include the study of heat transfer effects in the die and meniscus regions.

  16. Pain in Times of Stress

    PubMed Central

    AHMAD, Asma Hayati; ZAKARIA, Rahimah

    2015-01-01

    Stress modulates pain perception, resulting in either stress-induced analgesia or stress-induced hyperalgesia, as reported in both animal and human studies. The responses to stress include neural, endocrine, and behavioural changes, and built-in coping strategies are in place to address stressors. Peculiar to humans are additional factors that modulate pain that are experienced in times of stress, notably psychological factors that potentially influence the directionality of pain perception. PMID:27006638

  17. DAN Active Parameters and Mastcam Hydration Survey Imaging: Comparisons Across Yellowknife Bay, Gale Crater, Mars

    NASA Astrophysics Data System (ADS)

    Hardgrove, C. J.; Rice, M. S.; Moersch, J.; Mitrofanov, I. G.; Litvak, M.; Wellington, D. F.; Behar, A.; Bell, J. F.; Boynton, W. V.; DeFlores, L.; Drake, D.; Fedosov, F.; Golovin, D.; Jun, I.; Harshman, K.; Kozyrev, A.; Malakhov, A.; Milliken, R.; Kuzmin, R.; Mischna, M. A.; Mokrousov, M.; Nikiforov, S.; Sanin, A.; Tate, C.; Team, M.

    2013-12-01

    The Dynamic Albedo of Neutrons (DAN) instrument on the Mars Science Laboratory (MSL) rover Curiosity has recorded variability in neutron counts along traverses in and around Yellowknife Bay that suggest variable amounts of hydrogen (H) are present. At the locations of several DAN observations, Mastcam 'hydration survey' mosaics have been acquired with the R0 (493 nm, 551 nm and 638 nm), R5 (937 nm) and R6 (1013 nm) science filters to characterize RGB color and look for potential hydration as indicated by an absorption near 1000 nm. Whereas DAN is sensitive to H abundance down to 60cm depth, the Mastcam hydration index is sensitive to the presence of certain hydrated minerals (bound-OH and/or H2O) exposed in the upper hundreds of micrometers of the surface. Furthermore, many light-toned, Ca-sulfate-bearing features (i.e. veins and nodules within the outcrop) exposed at the surface in Yellowknife Bay have a high hydration index, consistent with a hydrated mineral such as gypsum. Other light-toned features do not have a high hydration index, suggesting they are composed of anhydrous or lower hydration state phases such as anhydrite or bassanite. The distribution of light-toned features within the outcrop at Yellowknife Bay is also highly variable within a DAN footprint. Given that there is variability in both the DAN signal and Mastcam hydration index throughout Yellowknife Bay, this work investigates whether or not increases or decreases in H seen by DAN correlate to areas of high hydration index as derived from Mastcam observations. Positive correlations of the DAN H signal and Mastcam hydration index may indicate that the observed densities of light-toned features (hydrated or dehydrated) extend to at least 60cm depth. Conversely, negative correlations could indicate that either the veins/nodules are only present at very shallow depths (a few cm), that the hydration of the phases changes with depth (e.g., gypsum at the surface and anhydrite at depth), or that there

  18. Sacroiliites infectieuses dans le centre tunisien: étude rétrospective de 25 cas

    PubMed Central

    Bellazreg, Foued; Alaya, Zeineb; Hattab, Zouhour; Lasfar, Nadia Ben; Ayeche, Mohamed Laziz Ben; Bouajina, Elyes; Letaief, Amel; Hachfi, Wissem

    2016-01-01

    Les sacroiliites infectieuses sont rares mais peuvent se compliquer de séquelles fonctionnelles invalidantes. Décrire les caractéristiques cliniques et bactériologiques des sacroiliites infectieuses chez les patients suivis à Sousse, Centre Tunisien. Etude rétrospective, descriptive, des cas de sacroiliites infectieuses chez les patients hospitalisés à Sousse entre 2000 et 2015. Le diagnostic a été retenu devant des signes cliniques, d'imagerie, et microbiologiques évocateurs. Vingt-cinq patients, 10 hommes et 15 femmes, d’âge moyen 41 ans (19-78) ont été inclus. Les sacroiliites étaient dues à des bactéries pyogènes dans 14 cas (56%), brucelliennes dans 6 cas (24%), et tuberculeuses dans 5 cas (20%). La durée moyenne d’évolution était de 61, 45 et 402 jours respectivement. Les signes cliniques les plus fréquents étaient les douleurs fessières (92%) et la fièvre (88%). La radiographie standard était anormale dans 75% des cas. La TDM et l'IRM sacro-iliaques dans tous les cas. Le diagnostic a été confirmé bactériologiquement dans 24 cas (96%). La durée moyenne d'antibiothérapie était de 83 jours dans les sacroiliites à pyogènes, et de 102 jours dans les SI brucelliennes. L’évolution était favorable chez 12 patients (48%), 9 patients (36%) ont gardé une douleur sacro-iliaque séquellaire, et 4 patients (16%) sont décédés. Dans notre étude, la durée d’évolution de la sacroiliite infectieuse ne permettait pas de prédire la bactérie responsable, d'où la nécessité d'obtenir une documentation bactériologique afin de prescrire une antibiothérapie appropriée. PMID:27583067

  19. Stress and efficiency studies

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Optical and electrical characterization of defects has been started in EFG ribbon grown in a system that will be used to test the stress model. Temperature and stress field modeling aimed at defining low stress growth configuration is also in progress, and results will be used to guide development of the experimental system. The baseline defect configuration for ribbon grown at speeds of approx. 1 cm/min consists of dislocation densities of the order of 10 to the 5th power to 10 to the 6th power/sq cm, as well as saucer type etch pits and line defects. All these defects are inhomogeneously distributed. EBIC measurements indicate that diffusion lengths are in the range 20 to 60 microns, and significant spatial inhomogeneities occur through the ribbon thickness. Growth speed changes in the range 0.7-1.0 cm/min do not produce significant variations in ribbon defect configurations.

  20. Stress corrosion resistant fasteners

    NASA Technical Reports Server (NTRS)

    Roach, T. A.

    1985-01-01

    A family of high performance aerospace fasteners made from corrosion resistant alloys for use in applications where corrosion and stress-corrosion cracking are of major concern are discussed. The materials discussed are mainly A-286, Inconel 718, MP35N and MP159. Most of the fasteners utilize cold worked and aged materials to achieve the desired properties. The fasteners are unique in that they provide a combination of high strength and immunity to stress corrosion cracking not previously attainable. A discussion of fastener stress corrosion failures is presented including a review of the history and a description of the mechanism. Case histories are presented to illustrate the problems which can arise when material selection is made without proper regard for the environmental conditions. Mechanical properties and chemical compositions are included for the fasteners discussed. Several aspects of the application of high performance corrosion resistant fasteners are discussed including galvanic compatibility and torque-tension relationships.

  1. [Stress and optimal ageing].

    PubMed

    Gogol, Manfred

    2015-08-01

    Stress is a stimulus or incident which has an exogenic or endogenic influence on an organism and leads to a biological and/or psychological adaptation from the organism by adaptation. Stressors can be differentiated by the temporal impact (e.g. acute, chronic or acute on chronic), strength and quality. The consequences of stress exposure and adaptation can be measured at the cellular level and as (sub) clinical manifestations, where this process can be biologically seen as a continuum. Over the course of life there is an accumulation of stress incidents resulting in a diminution of the capability for adaptation and repair mechanisms. By means of various interventions it is possible to improve the individual capability for adaptation but it is not currently definitively possible to disentangle alterations due to ageing and the development of diseases. As a consequence the term "healthy ageing" should be replaced by the concept of "optimal ageing". PMID:26208575

  2. Stress in expatriates.

    PubMed

    Lei, L; Liang, Y X; Krieger, Gary R

    2004-02-01

    With economic globalization, the rate and effects of culture shock stress in expatriates and their families are expected to increase. The stressor may occur from the micro-environment, the macro-environment, or the mega-environment. The effects of stress are frequently due to predictable reactions such as insecurity, distress, and homesickness. These symptoms can progress to more severe psychosomatic symptoms, including depressive reactions and overt psychopathic behavior. Cross-cultural training programs are currently the best preventive strategy for culture shock and subsequent stress; however, the true efficacy of these programs is not well characterized. Substance abuse is probably a significant underlying problem for international business travelers; however, the true magnitude and effects of this issue are not well characterized in the expatriate community. There are substantial opportunities for additional medical research in these areas. PMID:15043372

  3. Stress and hypertension.

    PubMed Central

    Mustacchi, P.

    1990-01-01

    In susceptible persons emotional stress results in immediate sympathetic stimulation, with a vasomotor response that results in a high-output state and elevated blood pressure; the vasopressor response seems to be transient. There seems to be no longitudinal epidemiologic validation of the attractive hypothesis that transiently elevated blood pressures are the prelude to fixed hypertension, however. The acquisition of hypertension by populations abandoning their traditional mode of living has been attributed to the sociocultural stress inherent in westernization, but these studies usually have not taken into account concomitants of this type of acculturation, such as dietary changes and increased body weight. The inverse relationship of blood pressure levels to education could explain the development of hypertension when aspiration to upward mobility is thwarted. The severity of perceived occupational stress relates inversely to blood pressure, suggesting that familiarity with a job renders the demands made by the work environment more predictable and less threatening in terms of vasopressor response. PMID:2219875

  4. Stress wave focusing transducers

    SciTech Connect

    Visuri, S.R., LLNL

    1998-05-15

    Conversion of laser radiation to mechanical energy is the fundamental process behind many medical laser procedures, particularly those involving tissue destruction and removal. Stress waves can be generated with laser radiation in several ways: creation of a plasma and subsequent launch of a shock wave, thermoelastic expansion of the target tissue, vapor bubble collapse, and ablation recoil. Thermoelastic generation of stress waves generally requires short laser pulse durations and high energy density. Thermoelastic stress waves can be formed when the laser pulse duration is shorter than the acoustic transit time of the material: {tau}{sub c} = d/c{sub s} where d = absorption depth or spot diameter, whichever is smaller, and c{sub s} = sound speed in the material. The stress wave due to thermoelastic expansion travels at the sound speed (approximately 1500 m/s in tissue) and leaves the site of irradiation well before subsequent thermal events can be initiated. These stress waves, often evolving into shock waves, can be used to disrupt tissue. Shock waves are used in ophthalmology to perform intraocular microsurgery and photodisruptive procedures as well as in lithotripsy to fragment stones. We have explored a variety of transducers that can efficiently convert optical to mechanical energy. One such class of transducers allows a shock wave to be focused within a material such that the stress magnitude can be greatly increased compared to conventional geometries. Some transducer tips could be made to operate regardless of the absorption properties of the ambient media. The size and nature of the devices enable easy delivery, potentially minimally-invasive procedures, and precise tissue- targeting while limiting thermal loading. The transducer tips may have applications in lithotripsy, ophthalmology, drug delivery, and cardiology.

  5. Spectres d'absorption X dans les plasmas femtosecondes

    NASA Astrophysics Data System (ADS)

    Bastiani-Ceccotti, S.; Audebert, P.; Renaudin, P.; Chenais-Popovics, C.; Geindre, J. P.; Tzortzakis, S.; Nagels-Silvert, V.; Shepherd, R.; Matsushima, I.; Gary, S.; Girard, F.; Peyrusse, O.; Gauthier, J. C.

    2005-06-01

    Nous avons mesuré le spectre d'absorption en couche K de plasmas d'aluminium à haute densité. Deux faisceaux de la chaîne laser femtoseconde 100 TW du LULI (de durée 300 fs) ont été utilisés pour produire le plasma absorbant sur une feuille mince d'Al (830 Å ou 500 Å), et la source de radiographie sur du samarium massif. Les spectres X étaient résolus spatialement dans une direction perpendiculaire à la direction de la dispersion spectrale. Les spectres ont été mesurés pour différents retards entre la source deradiographie et le plasma d'Al. Des simulations des spectres et de l'ionisation en fonction du temps et de l'intensité, obtenues au moyen de codes hydrodynamiques et de structure atomique, montrent un bon accord avec les résultats expérimentaux.

  6. Stress in service members.

    PubMed

    Lande, R Gregory

    2014-12-01

    Military service differs from civilian jobs in the stressors that service members experience, including frequent deployments (eg, to an area of combat operations), obedience, regimentation, subordination of self to the group, integrity, and flexibility. The military culture emphasizes teamwork and peer support. In some cases, service members cannot adapt to military life, become overwhelmed by stress, or cannot overcome a traumatic experience. Clinicians should conduct a thorough evaluation guided by an understanding of the military culture. Every effort should be made to identify the stress and the maladaptive response and provide early clinical interventions to prevent progression. PMID:25455065

  7. Migration pelvienne de broche guide dans la chirurgie des fractures de hanche: à propos de 3 cas

    PubMed Central

    Guèye, Mohamadou Lamine; Thiam, Ousmane; Touré, Alpha Oumar; Seck, Mamadou; Cissé, Mamadou; Kâ, Ousmane; Dieng, Madieng; Dia, Abderahmane; Touré, Cheikh Tidiane

    2015-01-01

    La migration de matériel d'ostéosynthèse est une complication bien connue du traitement chirurgical des fractures. Toutefois, la migration pelvienne de broche guide dans la chirurgie des fractures de la hanche est un incident rare et potentiellement grave. Nous rapportons 3 observations dans lesquelles on notait une migration de broche guide dans le pelvis lors d'une ostéosynthèse dela hanche de type DHS. L'indication chirurgicale était une fracture per-trochantérienne dans 2 cas et une fracture du col fémoral type 4 de Garden dans 1 cas. Une minilaparotomie permettait d'objectiver une plaie du ligament large gauche et un hématome ligamentaire dans 1 cas, tandis que dans les 2 autres cas, il n'y avait pas de lésion viscérale. L'extraction de la broche a été effectuée dans les 3 cas. Les suites opératoires ont été simples chez tous les patients. PMID:26327949

  8. Stress and personality.

    PubMed

    Lecic-Tosevski, D; Vukovic, O; Stepanovic, J

    2011-01-01

    Stress is an adaptation reaction of living organisms in response to internal or external threats to homeostasis. It is considered as a complex defence mechanism representing the final endpoint of numerous dynamic and interconnected factors of biological, psychological and social nature. Stress is not a simple, stimulus-response reaction, but the interaction between an individual and the environment, involving subjective perception and assessment of stressors, thus constituting a highly personalized process. Specific inherited characteristics, early experience in life, and particular, learned cognitive predispositions make individuals more or less susceptible to the effects of stressors. Resilience and vulnerability to stressors as well as intensity of stress response are greatly dependable on age, gender, intelligence, and numerous characteristics of personality, such as hardiness,locus of control, self-efficacy, self-esteem, optimism, hostility (component of type A personality)and type D traits (negative affectivity and social inhibition). To understand the relation between personality and stress, it is essential to recognize the impact of individual differences in the following four aspects: (1) choice or avoidance of environments that are associated with specific stressors, challenges or benefits, (2) way of interpreting a stressful situation and evaluating one's own abilities and capacities for proactive behaviour so as to confront or avoid it, (3) intensity of response to a stressor,and (4) coping strategies employed by the individual facing a stressful situation. Studies have recorded considerable consistency in coping strategies employed to confront stressful situations, independentlyof situational factors and in connection with permanent personality and temperamental traits,such as neuroticism, extraversion, sense of humour, persistence, fatalism, conscientiousness, andopenness to experience. Positive affect has been associated with positive reappraisal

  9. The local subsurface water and chlorine distributions evaluated by DAN/MSL in Curiosity observational campaigns

    NASA Astrophysics Data System (ADS)

    Litvak, Maxim; Mitrofanov, Igor; Hardgrove, Craig; Sanin, Anton; Lisov, Denis; Golovin, Dmitry; Jun, Insoo; Kozyrev, Alexander; Malakhov, Alexey; Mischna, Michael; Moersch, Jeffrey; Nikiforov, Sergey; Tate, Cristopher; Vostrukhin, Andrey

    2016-04-01

    The measurements with the Dynamic Albedo of Neutrons (DAN) instrument onboard the Mars Science Laboratory (MSL) Curiosity rover are presented and analyzed as a summary of observations acquired during several special observational campaigns at the Yellowknife Bay area (first discovery of habitability environment), at the striated units of Kimberley formation, at outcrops studied in Pahrump Hills (at the base of Mt Sharp) and in high silica area discovered in Marias Pass (Mudstone facies of the Murray formation). DAN data were analyzed to test local and global variability in the distribution of bulk hydrogen and neutron-absorbing elements, characterized as chlorine-equivalent concentration. Using multi instrument approach in the data analysis we have compared DAN estimations of subsurface H and Cl distributions with inhomogeneity of local geological context, top surface measurements of chlorine with APXS and with SAM measurements of absorbed H2O extracted from the drilled samples based on low temperature evolved gas analysis.

  10. Dynamic Albedo of Neutrons (DAN) Experiment Onboard NASA's Mars Science Laboratory

    NASA Astrophysics Data System (ADS)

    Mitrofanov, I. G.; Litvak, M. L.; Varenikov, A. B.; Barmakov, Y. N.; Behar, A.; Bobrovnitsky, Y. I.; Bogolubov, E. P.; Boynton, W. V.; Harshman, K.; Kan, E.; Kozyrev, A. S.; Kuzmin, R. O.; Malakhov, A. V.; Mokrousov, M. I.; Ponomareva, S. N.; Ryzhkov, V. I.; Sanin, A. B.; Smirnov, G. A.; Shvetsov, V. N.; Timoshenko, G. N.; Tomilina, T. M.; Tret'yakov, V. I.; Vostrukhin, A. A.

    2012-09-01

    The description of Dynamic Albedo of Neutrons (DAN) experiment is presented, as a part of the NASA's Mars Science Laboratory mission onboard the mars rover Curiosity. The instrument DAN includes Pulsing Neutron Generator (PNG) producing pulses of 14.1 MeV neutrons for irradiation of subsurface material below the rover, and Detectors and Electronics (DE) unit, which operates the instrument itself and measures the die-away time profiles of epithermal and thermal neutrons following each neutron pulse. It is shown that the DAN investigation will measure a content of hydrogen along the path of the MSL rover, and it will also provide information about a depth distribution of hydrogen at 10-20 regions selected for the detailed studies and sampling analysis.

  11. Help for Stressed Students

    ERIC Educational Resources Information Center

    Pope, Denise Clarke; Simon, Richard

    2005-01-01

    The authors argue that increased focus and pressure for high academic achievement, particularly among more highly-motivated and successful students, may have serious negative consequences. They present a number of strategies designed to help reduce both causes and consequences associated with academic stress and improve students' mental and…

  12. Stress Reactions to Bereavement

    ERIC Educational Resources Information Center

    Vachon, M. L. S.; And Others

    1976-01-01

    This paper presents preliminary data on 100 subjects of the first longitudinal study of Canadian widows. Widows have more psychological problems than a comparison group of women under treatment for breast cancer. Widows living alone with dependent children report higher stress levels. (Author)

  13. Stress in medical students.

    PubMed

    Nechita, Florina; Nechita, Dan; Pîrlog, Mihail Cristian; Rogoveanu, Ion

    2014-01-01

    Stress has been defined as the state of a body threatened by imbalance under the influence of agents or conditions endangering its homeostatic mechanisms but the concept have multiple meanings in correlation with the origin and biological support of its effects. Also, stressors are multiple, recording one of the highest levels during the academic studies. For the medical students, stress represents an important challenge, especially during the first year of medical school, caused by the absence of a learning strategy, the sleepless night before the exam and also an unhealthy food intake during the exams. The coping strategies are important, their background being represented by the social support, especially within the family, and emotional, the passions of the medicine students being the most important stress-combating factor. Gender represents also an important factor for the stress vulnerability, manifested through medical and psychiatric symptoms. In order to train good doctors, fair and above all healthy, it is important to consider not only the information we want to transmit, but also the context in which we educate. PMID:25607418

  14. Stress in Children Bibliography.

    ERIC Educational Resources Information Center

    Gerlach, Kent

    This annotated bibliography concerns itself with issues that may contribute to childhood stress, provides resource materials for teachers and parents, and covers a wide variety of fiction and non-fiction for students (K-12). The publication's organization along with examples of the issues included follows: (1) adolescence issues (substance abuse,…

  15. Mobbing and Stress

    ERIC Educational Resources Information Center

    Yaman, Erkan

    2015-01-01

    Mobbing is an important construct which has impact on the numerous psychological variables. The purpose of this study is to examine the relationships between mobbing and stress. Participants were 436 teachers (206 (55%) were female, 230 (45%) were male) from Sakarya, Turkey. Their ages ranged from 26 to 55 years and the mean age of the…

  16. Stress and Child Development

    ERIC Educational Resources Information Center

    Thompson, Ross A.

    2014-01-01

    Children's early social experiences shape their developing neurological and biological systems for good or for ill, writes Ross Thompson, and the kinds of stressful experiences that are endemic to families living in poverty can alter children's neurobiology in ways that undermine their health, their social competence, and their ability…

  17. Children's Stress Index.

    ERIC Educational Resources Information Center

    Sherman, Dianne, Ed.

    1993-01-01

    This double issue of the "ZPG Reporter" focuses on the theme of ZPG's Children's Stress Index", the first national survey of children's well-being based on population- related pressures. Using an extensive list of social, economic, and environmental factors that affect the lives of children, the index ranks 828 cities, counties, and metropolitan…

  18. Exercise stress testing

    NASA Technical Reports Server (NTRS)

    Schuster, B.

    1975-01-01

    Positive maximum stress tests in the management of coronary patients are discussed. It is believed that coronary angiography would be the ultimate test to predict the future of patients with coronary heart disease. Progression of angina, myocardial infarction, and death due to heart disease were analyzed.

  19. Stress and the Kidney

    PubMed Central

    Bruce, Marino A.; Griffith, Derek M.; Thorpe, Roland J.

    2016-01-01

    The prevalence of CKD has increased considerably over the past 2 decades. The rising rates of CKD have been attributed to known comorbidities such as diabetes, hypertension, and obesity; however, recent research has begun to explore the degree to which social, economic, and psychological factors have implications for the prevalence and progression of CKD, especially among high-risk populations such as African Americans. It has been suggested that stress can have implications for CKD, but this area of research has been largely unexplored. One contributing factor associated with the paucity of research on CKD is that many of the social, psychological, and environmental stressors cannot be recreated or simulated in a laboratory setting. Social science has established that stress can have implications for health, and we believe that stress is an important determinant of the development and progression of CKD. We draw heavily from the social scientific and social epidemiologic literature to present an intersectional conceptual frame specifying how stress can have implications for kidney disease, its progression, and its complications through multiple stressors and pathways. PMID:25573512

  20. Thermal stress and toxicity.

    PubMed

    Gordon, Christopher J; Johnstone, Andrew F M; Aydin, Cenk

    2014-07-01

    Elevating ambient temperature above thermoneutrality exacerbates toxicity of most air pollutants, insecticides, and other toxic chemicals. On the other hand, safety and toxicity testing of toxicants and drugs is usually performed in mice and rats maintained at sub-thermoneutral temperatures of ~22∘C. When exposed to chemical toxicants under these relatively cool conditions, rodents typically undergo a regulated hypothermic response, characterized by preference for cooler ambient temperatures and controlled reduction in core temperature. Reducing core temperature delays the clearance of most toxicants from the body; however, a mild hypothermia also improves recovery and survival from the toxicant. Raising ambient temperature to thermoneutrality and above increases the rate of clearance of the toxicant but also exacerbates toxicity. Furthermore, heat stress combined with work or exercise is likely to worsen toxicity. Body temperature of large mammals, including humans, does not decrease as much in response to exposure to a toxicant. However, heat stress can nonetheless worsen toxic outcome in humans through a variety of mechanisms. For example, heat-induced sweating and elevation in skin blood flow accelerates uptake of some insecticides. Epidemiological studies suggest that thermal stress may exacerbate the toxicity of airborne pollutants such as ozone and particulate matter. Overall, translating results of studies in rodents to that of humans is a formidable task attributed in part to the interspecies differences in thermoregulatory response to the toxicants and to thermal stress. PMID:24944028

  1. STRESS TESTING OF WOODSTOVES

    EPA Science Inventory

    The paper discusses stress testing of woodstoves. tress testing is a way to test the long- term durability of woodstove models in the laboratory in a 1 to 2 week time frame. (NOTE: Woodstove field studies have shown that new technology woodstoves designed to have low particulate ...

  2. Learn to manage stress

    MedlinePlus

    ... meditation to yoga and tai chi. Take a class, or try learning from books, videos, or online sources. Connect with loved ones. Do not let stress get in the way of being social. Spending time with family and friends can help ...

  3. Detecting Plant Stress

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Through an exclusive patent license from NASA Stennis Space Center, Spectrum Technologies, Inc., has developed a hand-held tool that helps farmers, foresters and other growers detect unhealthy crops before the human eye can see the damage. Developed by two NASA researchers, the Observer,TM shows the viewer which plants are under stress through multispectral imaging, a process that uses specific wavelengths of the light spectrum to obtain information about objects-in this case, plants. With this device, several wavelengths of light collect information about the plant and results are immediately processed and displayed. NASA research found that previsible signs of stress, such as such as a lack of nutrients, insufficient water, disease, or insect damage, can be detected by measuring the chlorophyll content based on light energy reflected from the plant. The Observer detects stress up to 16 days before deterioration is visible to the eye. Early detection provides an opportunity to reverse stress and save the plant. The hand-held, easily operated unit works in both natural and artificial light, making it suitable for outdoor or indoor planting.

  4. Stress in Harmonic Serialism

    ERIC Educational Resources Information Center

    Pruitt, Kathryn Ringler

    2012-01-01

    This dissertation proposes a model of word stress in a derivational version of Optimality Theory (OT) called Harmonic Serialism (HS; Prince and Smolensky 1993/2004, McCarthy 2000, 2006, 2010a). In this model, the metrical structure of a word is derived through a series of optimizations in which the "best" metrical foot is chosen…

  5. Stress and the kidney.

    PubMed

    Bruce, Marino A; Griffith, Derek M; Thorpe, Roland J

    2015-01-01

    The prevalence of CKD has increased considerably over the past 2 decades. The rising rates of CKD have been attributed to known comorbidities such as diabetes, hypertension, and obesity; however, recent research has begun to explore the degree to which social, economic, and psychological factors have implications for the prevalence and progression of CKD, especially among high-risk populations such as African Americans. It has been suggested that stress can have implications for CKD, but this area of research has been largely unexplored. One contributing factor associated with the paucity of research on CKD is that many of the social, psychological, and environmental stressors cannot be recreated or simulated in a laboratory setting. Social science has established that stress can have implications for health, and we believe that stress is an important determinant of the development and progression of CKD. We draw heavily from the social scientific and social epidemiologic literature to present an intersectional conceptual frame specifying how stress can have implications for kidney disease, its progression, and its complications through multiple stressors and pathways. PMID:25573512

  6. Stress/Burnout Report.

    ERIC Educational Resources Information Center

    Collins, James J., Ed.; Masley, Barbara A., Ed.

    1980-01-01

    The awareness of the effects of stress on school personnel and its effects on student achievement led to the formation of a committee to examine the problem and establish some objectives. A copy of the questionnaire submitted to the personnel of the Worchester, Massachusetts, Public Schools is presented. Job related factors were listed with…

  7. Meditation and Teacher Stress

    ERIC Educational Resources Information Center

    Csaszar, Imre Emeric; Buchanan, Teresa

    2015-01-01

    Early childhood teachers can be relaxed and peaceful as they create playful and harmonious classrooms, even if they work in stressful contexts. However, the stressors faced by teachers may lead to negative consequences that can undermine their ability to sustain personal health and positive interactions. In the absence of positive coping…

  8. Residual stresses in material processing

    SciTech Connect

    Kozaczek, K.J.; Watkins, T.R.; Hubbard, C.R.; Wang, Xun-Li; Spooner, S.

    1994-09-01

    Material manufacturing processes often introduce residual stresses into the product. The residual stresses affect the properties of the material and often are detrimental. Therefore, the distribution and magnitude of residual stresses in the final product are usually an important factor in manufacturing process optimization or component life prediction. The present paper briefly discusses the causes of residual stresses. It then adresses the direct, nondestructive methods of residual stress measurement by X-ray and neutron diffraction. Examples are presented to demonstrate the importance of residual stress measurement in machining and joining operations.

  9. Stress and child development.

    PubMed

    Thompson, Ross A

    2014-01-01

    Children's early social experiences shape their developing neurological and biological systems for good or for ill, writes Ross Thompson, and the kinds of stressful experiences that are endemic to families living in poverty can alter children's neurobiology in ways that undermine their health, their social competence, and their ability to succeed in school and in life. For example, when children are born into a world where resources are scarce and violence is a constant possibility, neurobiological changes may make them wary and vigilant, and they are likely to have a hard time controlling their emotions, focusing on tasks, and forming healthy relationships. Unfortunately, these adaptive responses to chronic stress serve them poorly in situations, such as school and work, where they must concentrate and cooperate to do well. But thanks to the plasticity of the developing brain and other biological systems, the neurobiological response to chronic stress can be buffered and even reversed, Thompson writes, especially when we intervene early in children's lives. In particular, warm and nurturing relationships between children and adults can serve as a powerful bulwark against the neurobiological changes that accompany stress, and interventions that help build such relationships have shown particular promise. These programs have targeted biological parents, of course, but also foster parents, teachers and other caregivers, and more distant relatives, such as grandparents. For this reason, Thompson suggests that the concept of two-generation programs may need to be expanded, and that we should consider a "multigenerational" approach to helping children living in poverty cope and thrive in the face of chronic stress. PMID:25518702

  10. Earthquake Apparent Stress Scaling

    NASA Astrophysics Data System (ADS)

    Walter, W. R.; Mayeda, K.; Ruppert, S.

    2002-12-01

    There is currently a disagreement within the geophysical community on the way earthquake energy scales with magnitude. One set of recent papers finds evidence that energy release per seismic moment (apparent stress) is constant (e.g. Choy and Boatwright, 1995; McGarr, 1999; Ide and Beroza, 2001). Another set of recent papers finds the apparent stress increases with magnitude (e.g. Kanamori et al., 1993 Abercrombie, 1995; Mayeda and Walter, 1996; Izutani and Kanamori, 2001). The resolution of this issue is complicated by the difficulty of accurately accounting for and determining the seismic energy radiated by earthquakes over a wide range of event sizes in a consistent manner. We have just started a project to reexamine this issue by analyzing aftershock sequences in the Western U.S. and Turkey using two different techniques. First we examine the observed regional S-wave spectra by fitting with a parametric model (Walter and Taylor, 2002) with and without variable stress drop scaling. Because the aftershock sequences have common stations and paths we can examine the S-wave spectra of events by size to determine what type of apparent stress scaling, if any, is most consistent with the data. Second we use regional coda envelope techniques (e.g. Mayeda and Walter, 1996; Mayeda et al, 2002) on the same events to directly measure energy and moment. The coda techniques corrects for path and site effects using an empirical Green function technique and independent calibration with surface wave derived moments. Our hope is that by carefully analyzing a very large number of events in a consistent manner using two different techniques we can start to resolve this apparent stress scaling issue. This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.

  11. Oxidative stress in autism.

    PubMed

    Chauhan, Abha; Chauhan, Ved

    2006-08-01

    Autism is a severe developmental disorder with poorly understood etiology. Oxidative stress in autism has been studied at the membrane level and also by measuring products of lipid peroxidation, detoxifying agents (such as glutathione), and antioxidants involved in the defense system against reactive oxygen species (ROS). Lipid peroxidation markers are elevated in autism, indicating that oxidative stress is increased in this disease. Levels of major antioxidant serum proteins, namely transferrin (iron-binding protein) and ceruloplasmin (copper-binding protein), are decreased in children with autism. There is a positive correlation between reduced levels of these proteins and loss of previously acquired language skills in children with autism. The alterations in ceruloplasmin and transferrin levels may lead to abnormal iron and copper metabolism in autism. The membrane phospholipids, the prime target of ROS, are also altered in autism. The levels of phosphatidylethanolamine (PE) are decreased, and phosphatidylserine (PS) levels are increased in the erythrocyte membrane of children with autism as compared to their unaffected siblings. Several studies have suggested alterations in the activities of antioxidant enzymes such as superoxide dismutase, glutathione peroxidase, and catalase in autism. Additionally, altered glutathione levels and homocysteine/methionine metabolism, increased inflammation, excitotoxicity, as well as mitochondrial and immune dysfunction have been suggested in autism. Furthermore, environmental and genetic factors may increase vulnerability to oxidative stress in autism. Taken together, these studies suggest increased oxidative stress in autism that may contribute to the development of this disease. A mechanism linking oxidative stress with membrane lipid abnormalities, inflammation, aberrant immune response, impaired energy metabolism and excitotoxicity, leading to clinical symptoms and pathogenesis of autism is proposed. PMID:16766163

  12. DAnTE: a statistical tool for quantitative analysis of –omics data

    SciTech Connect

    Polpitiya, Ashoka D.; Qian, Weijun; Jaitly, Navdeep; Petyuk, Vladislav A.; Adkins, Joshua N.; Camp, David G.; Anderson, Gordon A.; Smith, Richard D.

    2008-05-03

    DAnTE (Data Analysis Tool Extension) is a statistical tool designed to address challenges unique to quantitative bottom-up, shotgun proteomics data. This tool has also been demonstrated for microarray data and can easily be extended to other high-throughput data types. DAnTE features selected normalization methods, missing value imputation algorithms, peptide to protein rollup methods, an extensive array of plotting functions, and a comprehensive ANOVA scheme that can handle unbalanced data and random effects. The Graphical User Interface (GUI) is designed to be very intuitive and user friendly.

  13. Stress inoculation modeled in mice

    PubMed Central

    Brockhurst, J; Cheleuitte-Nieves, C; Buckmaster, C L; Schatzberg, A F; Lyons, D M

    2015-01-01

    Stress inoculation entails intermittent exposure to mildly stressful situations that present opportunities to learn, practice and improve coping in the context of exposure psychotherapies and resiliency training. Here we investigate behavioral and hormonal aspects of stress inoculation modeled in mice. Mice randomized to stress inoculation or a control treatment condition were assessed for corticosterone stress hormone responses and behavior during open-field, object-exploration and tail-suspension tests. Stress inoculation training sessions that acutely increased plasma levels of corticosterone diminished subsequent immobility as a measure of behavioral despair on tail-suspension tests. Stress inoculation also decreased subsequent freezing in the open field despite comparable levels of thigmotaxis in mice from both treatment conditions. Stress inoculation subsequently decreased novel-object exploration latencies and reduced corticosterone responses to repeated restraint. These results demonstrate that stress inoculation acutely stimulates glucocorticoid signaling and then enhances subsequent indications of active coping behavior in mice. Unlike mouse models that screen for the absence of vulnerability to stress or presence of traits that occur in resilient individuals, stress inoculation training reflects an experience-dependent learning-like process that resembles interventions designed to build resilience in humans. Mouse models of stress inoculation may provide novel insights for new preventive strategies or therapeutic treatments of human psychiatric disorders that are triggered and exacerbated by stressful life events. PMID:25826112

  14. Stress: Neurobiology, consequences and management.

    PubMed

    Kumar, Anil; Rinwa, Puneet; Kaur, Gurleen; Machawal, Lalit

    2013-04-01

    Stress, both physical and psychological, is attracting increasing attention among neuroresearchers. In the last 20 decades, there has been a surge of interest in the research of stress-induced manifestations and this approach has resulted in the development of more appropriate animal models for stress-associated pathologies and its therapeutic management. These stress models are an easy and convenient method for inducing both psychological and physical stress. To understand the behavioral changes underlying major depression, molecular and cellular studies are required. Dysregulation of the stress system may lead to disturbances in growth and development, and may this may further lead to the development of various other psychiatric disorders. This article reviews the different types of stress and their neurobiology, including the different neurotransmitters affected. There are various complications associated with stress and their management through various pharmacological and non-pharmacological techniques. The use of herbs in the treatment of stress-related problems is practiced in both Indian and Western societies, and it has a vast market in terms of anti-stress medications and treatments. Non-pharmacological techniques such as meditation and yoga are nowadays becoming very popular as a stress-relieving therapy because of their greater effectiveness and no associated side effects. Therefore, this review highlights the changes under stress and stressor and their impact on different animal models in understanding the mechanisms of stress along with their effective and safe management. PMID:23833514

  15. Le pompage optique naturel dans le milieu astrophysique

    NASA Astrophysics Data System (ADS)

    Pecker, J.-C.

    The title of this lecture abstracts only a part of it : the importance in astrophysics of the study of non-LTE situations has become considerable, as well in the stellar atmospheres as, still more, in the study of fortuitous coincidences as a mechanism of formation of emission line nebular spectra, or of molecular interstellar « masers ». Another part of this talk underlines the role of Kastler in his time, and describes his warm personality through his public reactions in front of the nuclear armement, of the Viet-Nam and Algerian wars, of the problems of political refugees... Kastler was a great scientist ; he was also a courageous humanist. 1976 : Les accords nucléaires du Brésil : allocution d'ouverture (19 mars). Colloque sur le sujet ci-dessus. 1976 : La promotion de la culture dans le nouvel ordre économique international, allocution à l'occasion d'une table ronde sur ce thème par l'UNESCO (23-27 juin 1976) ; « Sciences et Techniques », octobre 1976. 1979 : La bête immonde (avec J.-C. Pecker), « Le Matin », 20 mars. 1979 : Appel à nos ministres (avec J.-C. Pecker), « Le Monde », 13 décembre. 1979 : Le flou, le ténébreux, l'irrationnel (avec J.-C. Pecker), « Le Monde », 14 septembre. 1980 : Education à la paix, Préface, in : Publ. UNESCO. 1981 : Le vrai danger, « Le Monde », 6 août 1981. 1982 : Nucléaire civil et militaire, « Le Monde », 1er juin 1982. 1982 : Les scientifiques face à la perspective d'holocauste nucléaire (texte inédit). Le titre de cette communication en résume seulement une partie : l'importance prise en astrophysique par l'analyse des situations hors ETL est devenue considérable, qu'il s'agisse des atmosphères stellaires, ou plus encore, des coïncidences fortuites de la formation des spectres d'émission nébulaires, ou des « masers » moléculaires interstellaires. Une autre partie de cet exposé souligne le rôle de Kastler dans son époque, et décrit sa personnalité généreuse à travers ses r

  16. Post-Traumatic Stress Disorder

    MedlinePlus

    ... PTSD include violent personal assaults, natural or human-caused disasters, accidents, or military combat. For Consumers General Information Post-Traumatic Stress Disorder ( NIMH ) Anxiety Information Stress Information Depression Information St. John's Wort Information See more Research ...

  17. Post-traumatic stress disorder

    MedlinePlus

    Post-traumatic stress disorder (PTSD) is a type of anxiety disorder . It can occur after you have gone through an extreme ... Normally, after the event, the body recovers. The stress hormones and chemicals the body releases due to ...

  18. Oxidative Stress and Psychological Disorders

    PubMed Central

    Salim, Samina

    2014-01-01

    Oxidative stress is an imbalance between cellular production of reactive oxygen species and the counteracting antioxidant mechanisms. The brain with its high oxygen consumption and a lipid-rich environment is considered highly susceptible to oxidative stress or redox imbalances. Therefore, the fact that oxidative stress is implicated in several mental disorders including depression, anxiety disorders, schizophrenia and bipolar disorder, is not surprising. Although several elegant studies have established a link between oxidative stress and psychiatric disorders, the causal relationship between oxidative stress and psychiatric diseases is not fully determined. Another critical aspect that needs much attention and effort is our understanding of the association between cellular oxidative stress and emotional stress. This review examines some of the recent discoveries that link oxidative status with anxiety, depression, schizophrenia and bipolar disorder. A discussion of published results and questions that currently exist in the field regarding a causal relationship between oxidative and emotional stress is also provided. PMID:24669208

  19. Defining Stress as Ethical Conflict.

    ERIC Educational Resources Information Center

    Speck, Bruce W.

    1993-01-01

    Explains the ethical grounding of stress. Suggests that stress leading to teacher burnout is a moral problem that can only be solved when a person evaluates his or her perceptions of what is right or good. (RS)

  20. Surgery for Stress Urinary Incontinence

    MedlinePlus

    ... Education FAQs Surgery for Stress Urinary Incontinence Patient Education Pamphlets - Spanish Surgery for Stress Urinary Incontinence FAQ166, July 2014 ... Your Practice Patient Safety & Quality Payment Reform (MACRA) Education & Events Annual ... Pamphlets Teen Health About ACOG About Us Leadership & ...

  1. Theorie de la Levitation Radiative a L'equilibre dans les Etoiles Naines Blanches Chaudes

    NASA Astrophysics Data System (ADS)

    Chayer, Pierre

    1995-01-01

    Les resultats de nouveaux calculs detailles de levitation radiative dans des naines blanches chaudes utilisant la base de donnees atomiques TOPBASE sont presentes. Des accelerations radiatives et des abondances d'equilibre ont ete calculees pour C, N, O, Ne, Na, Mg, Al, Si, S, Ar, Ca, et Fe, sur des grilles de modeles d'enveloppes stellaires riches en hydrogene et riches en helium. La grille des modeles de DA a des gravites telles que log g = 7.0, 7.5, 8.0, et 8.5, et couvre les temperatures effectives pour lesquelles 100,000K >= T_ {rm eff} >= 20,000K par sauts de 2,500K. La grille des modeles de DO/DB est similaire mais se prolonge a T_{rm eff } = 130,000K. Les resultats d'abondances d'equilibre de Ni dans des DA utilisant la base de donnees de Kurucz sont aussi presentes. Nous discutons dans les moindres details de la physique incluse dans les calculs afin de fournir une bonne comprehension physique de la levitation radiative sous les conditions rencontrees dans les naines blanches. Nous discutons aussi de la forme et de la dependance en fonction de la profondeur des reservoirs des elements, crees par un equilibre entre l'acceleration radiative et la gravite locale effective dans differentes enveloppes stellaires. Nous soulignons le role important joue dans la morphologie de ces reserviors par les etats d'ionisation dominants se trouvant dans la configuration gaz noble. Nos resultats centraux sont presentes sous forme de figures montrant le comportement de l'abondance photospherique estimee pour chaque element en fonction de la temperature effective et de la gravite de surface. Nous apportons egalement des ameliorations aux calculs de levitation radiative en utilisant une approche de modeles d'atmospheres pour les etoiles riches en hydrogene. Nous mettons l'emphase, en particulier, sur le role des traces d'elements lourds qui peuvent etre presents dans le plasma. Nous utilisons une table d'opacite monochromatique detaillee calculee pour un plasma compose de H

  2. Rock Stress, Rock Stress Measurements, and the Integrated Stress Determination Method (ISDM)

    NASA Astrophysics Data System (ADS)

    Ask, D.; Stephansson, O.; Cornet, F. H.; Ask, M. V. S.

    2009-08-01

    The primary objectives of this work are to (1) improve the understanding of the prevailing stress distribution at the Äspö Hard Rock Laboratory (HRL) in SE Sweden by employing an integrated stress determination approach, and in order to accomplish this (2) extend the existing stress integration methodology denominated integrated stress determination method (ISDM; Cornet in Comprehensive Rock Engineering vol 3, Pergamon Press, Oxford, pp 413-432, 1993a). The new developments of the ISDM involve a 12-parameter representation of the regional stress field in the rock mass (i.e., the full stress tensor and its variation with depth) that is applicable to hydraulic stress data (sleeve fracturing, hydraulic fracturing, and hydraulic tests on pre-existing fractures), overcoring data (CSIR- and CSIRO-type of devices), and to combinations of hydraulic and overcoring stress data. For the latter case, the elastic parameters of the overcoring technique may be solved in situ by allowing the hydraulic stress data to constrain them. As a result, the problem then involves 14 model parameters. Results from the study show that the ISDM effectively improves the precision of the prevailing stress field determination and that it is especially powerful for identification of consistencies/inconsistencies in an existing data set. Indeed, this is the very basic premise and goal of stress integration; combine all available data to achieve as complete a characterization of the mechanical stress model as possible, and not to identify a solution that fits only loosely the maximum amount of stress data.

  3. Stress studies in EFG

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Electrical characterization of defects induced in FZ and CZ silicon stress in four-point bending above 1200 C was started. Techniques to study electrical activity that will permit correlation of defect activity with diffusion length and with room and low temperature EBIC are being developed. Preliminary characterization of defects in ribbon grown at very low speeds of less than 1 cm/min shows that the dislocation density is very low over significant regions of cross section, while regions of high dislocation density (approx. 5 x 10(6)/cm(2)) occur in bands in a number of places. Addition measurements of stress distributions in EFG material were obtained at the University of Illinois using shadow-Moire interferometry.

  4. Cutaneous oxidative stress.

    PubMed

    Polefka, Thomas G; Meyer, Thomas A; Agin, Patricia P; Bianchini, Robert J

    2012-03-01

    The earliest known microfossil records suggest that microorganisms existed on the earth approximately 3.8 billion years ago. Not only did sunlight drive this evolutionary process, but it also allowed photosynthetic organisms to elaborate oxygen and fundamentally change the earth's atmosphere and subsequent evolution. Paradoxically, however, an atmosphere of 20% oxygen offers aerobic organisms both benefits and some key challenges, particularly, to the external integument. This mini-review summarizes almost 40 years of research and provides a "60 000-foot" perspective on cutaneous oxidative stress. Topics reviewed include the following: What are free radicals and reactive oxygen species? Where do they come from? What is their chemistry? What are their roles and/or impact on the skin? What antioxidant defenses are available to mitigate oxidative stress. PMID:22360336

  5. Thermoelastic Stress Analysis: The Mean Stress Effect in Metallic Alloys

    NASA Technical Reports Server (NTRS)

    Gyekenyesi, Andrew L.; Baaklini, George Y.

    1999-01-01

    The primary objective of this study involved the utilization of the thermoelastic stress analysis (TSA) method to demonstrate the mean stress dependence of the thermoelastic constant. Titanium and nickel base alloys, commonly employed in aerospace gas turbines, were the materials of interest. The repeatability of the results was studied through a statistical analysis of the data. Although the mean stress dependence was well established, the ability to confidently quantify it was diminished by the experimental variations. If calibration of the thermoelastic response to mean stress can be successfully implemented, it is feasible to use the relationship to determine a structure's residual stress state.

  6. Help Teachers Feel Less Stressed

    ERIC Educational Resources Information Center

    Richards, Jan

    2011-01-01

    The author's concern for how teachers nationwide are coping with unrelenting levels of stress is the topic of current research. A national sample of 1,200 teachers was asked to complete a survey addressing three areas: the sources of teacher stress; the manifestations of stress; and coping strategies they found most successful. Knowing the areas…

  7. Stress Factors among College Educators.

    ERIC Educational Resources Information Center

    Grant, George Farid

    Stress factors affecting community college educators in Ontario were determined using a questionnaire survey. The effect of demographic variables (campus location, program types and specialization, gender, age, and years taught at the college) on perceived stress levels were evaluated. Participants rated their present stress levels on a…

  8. Stress Management for Elementary Schools.

    ERIC Educational Resources Information Center

    Humphrey, James H.

    Stress management for school children has had various degrees of success. School officials need information about stress and how to deal with it. The purpose of this book is to provide information useful in inauguration of such programs where they do not exist. While stress management should begin in the home and include nutrition, physical…

  9. Stress Management as a Pacifier.

    ERIC Educational Resources Information Center

    Echterling, Lennis G.; Wylie, Mary Lou

    While numerous studies have identified economic, social, and environmental conditions related to stress, greater stress has been found to be related to poverty, unemployment, assembly line work, crowding, and chronic exposure to noise. These stressful situations most frequently confront people with little personal, economic, or political resources…

  10. Stress and the Professional Educator.

    ERIC Educational Resources Information Center

    Alley, Robert D.

    1980-01-01

    A description is given of some of the conditions surrounding schooling and education today which result in more stress for teachers and others directly involved with education. Working definitions of key terms pertaining to stress and teacher burnout are presented along with a general breakdown of some sources of stress. (JD)

  11. Police Stress: A Selected Bibliography.

    ERIC Educational Resources Information Center

    Duncan, J. T. Skip, Comp.; And Others

    The need to perform effectively under stress is a concern in many professions. For police officers and managers, who make split-second life and death decisions, the problem takes on added significance. The annotated documents compiled are in three sections: an overview to describe types and effects of stresses, police stress causal factors, and…

  12. Consultation Stressors and Stress Management.

    ERIC Educational Resources Information Center

    Portman, Sandy Kosub

    A high incidence of occupational stress has been demonstrated in the mental health and social service professions and appears to be a major factor contributing to low worker morale, absenteeism, high job turnover, and other indices of job stress. A study was conducted to examine the issue of occupational stress among psychological consultants.…

  13. Stress Responses of Shewanella

    PubMed Central

    Yin, Jianhua; Gao, Haichun

    2011-01-01

    The shewanellae are ubiquitous in aquatic and sedimentary systems that are chemically stratified on a permanent or seasonal basis. In addition to their ability to utilize a diverse array of terminal electron acceptors, the microorganisms have evolved both common and unique responding mechanisms to cope with various stresses. This paper focuses on the response and adaptive mechanism of the shewanellae, largely based on transcriptional data. PMID:21912550

  14. Oxidative Stress in Malaria

    PubMed Central

    Percário, Sandro; Moreira, Danilo R.; Gomes, Bruno A. Q.; Ferreira, Michelli E. S.; Gonçalves, Ana Carolina M.; Laurindo, Paula S. O. C.; Vilhena, Thyago C.; Dolabela, Maria F.; Green, Michael D.

    2012-01-01

    Malaria is a significant public health problem in more than 100 countries and causes an estimated 200 million new infections every year. Despite the significant effort to eradicate this dangerous disease, lack of complete knowledge of its physiopathology compromises the success in this enterprise. In this paper we review oxidative stress mechanisms involved in the disease and discuss the potential benefits of antioxidant supplementation as an adjuvant antimalarial strategy. PMID:23208374

  15. Stress Corrosion Testing

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Advanced testing of structural materials was developed by Lewis Research Center and Langley Research Center working with the American Society for Testing and Materials (ASTM). Under contract, Aluminum Company of America (Alcoa) conducted a study for evaluating stress corrosion cracking, and recommended the "breaking load" method which determines fracture strengths as well as measuring environmental degradation. Alcoa and Langley plan to submit the procedure to ASTM as a new testing method.

  16. Contact stress sensor

    DOEpatents

    Kotovsky, Jack

    2014-02-11

    A method for producing a contact stress sensor that includes one or more MEMS fabricated sensor elements, where each sensor element of includes a thin non-recessed portion, a recessed portion and a pressure sensitive element adjacent to the recessed portion. An electric circuit is connected to the pressure sensitive element. The circuit includes a pressure signal circuit element configured to provide a signal upon movement of the pressure sensitive element.

  17. Contact stress sensor

    DOEpatents

    Kotovsky, Jack

    2012-02-07

    A contact stress sensor includes one or more MEMS fabricated sensor elements, where each sensor element of includes a thin non-recessed portion, a recessed portion and a pressure sensitive element adjacent to the recessed portion. An electric circuit is connected to the pressure sensitive element. The circuit includes a thermal compensator and a pressure signal circuit element configured to provide a signal upon movement of the pressure sensitive element.

  18. Stressing mitosis to death.

    PubMed

    Burgess, Andrew; Rasouli, Mina; Rogers, Samuel

    2014-01-01

    The final stage of cell division (mitosis), involves the compaction of the duplicated genome into chromatid pairs. Each pair is captured by microtubules emanating from opposite spindle poles, aligned at the metaphase plate, and then faithfully segregated to form two identical daughter cells. Chromatids that are not correctly attached to the spindle are detected by the constitutively active spindle assembly checkpoint (SAC). Any stress that prevents correct bipolar spindle attachment, blocks the satisfaction of the SAC, and induces a prolonged mitotic arrest, providing the cell time to obtain attachment and complete segregation correctly. Unfortunately, during mitosis repairing damage is not generally possible due to the compaction of DNA into chromosomes, and subsequent suppression of gene transcription and translation. Therefore, in the presence of significant damage cell death is instigated to ensure that genomic stability is maintained. While most stresses lead to an arrest in mitosis, some promote premature mitotic exit, allowing cells to bypass mitotic cell death. This mini-review will focus on the effects and outcomes that common stresses have on mitosis, and how this impacts on the efficacy of mitotic chemotherapies. PMID:24926440

  19. Helping adolescents cope with stress during stressful times.

    PubMed

    Bonica, Cheryl; Daniel, Jessica Henderson

    2003-08-01

    Increasing levels of stress in the daily lives of adolescents is an important health concern. Adolescents experience a variety of stressful situations and use a wide range of coping strategies to help effectively manage stress. Recent research on adolescent coping with stressful situations is reviewed. Findings support an association between coping and adolescent health problems, chronic physical illness, and mental health. More research is needed to investigate the long-term benefits of coping with stress on adolescent health and well-being. Specific recommendations for helping adolescents cope with stressful situations are discussed. Health care providers are encouraged to assess how adolescents cope with acute and chronic stressors and provide adolescents with information about coping with stressful situations. PMID:12891050

  20. Cantilever measurements of surface stress, surface reconstruction, film stress and magnetoelastic stress of monolayers

    PubMed Central

    Sander, Dirk; Tian, Zhen; Kirschner, Jürgen

    2008-01-01

    We review the application of cantilever-based stress measurements in surface science and magnetism. The application of thin (thickness appr. 0.1 mm) single crystalline substrates as cantilevers has been used successfully to measure adsorbate-induced surface stress changes, lattice misfit induced film stress, and magneto-elastic stress of ferromagnetic monolayers. Surface stress changes as small as 0.01 N/m can be readily measured, and this translates into a sensitivity for adsorbate-coverage well below 0.01 of one layer. Stress as large as several GPa, beyond the elasticity limits of high strength materials, is measured, and it is ascribed to the lattice misfit between film and substrate. Our results point at the intimate relation between surface stress and surface reconstruction, stress-induced structural changes in epitaxially strained films, and strain-induced modifications of the magneto-elastic coupling in ferromagnetic monolayers.

  1. Interprétation cohérente du coefficient de Poisson négatif rapporté dans des multicouches métalliques : rôle du paramètre libre de contrainte

    NASA Astrophysics Data System (ADS)

    Badawi, K. F.; Goudeau, Ph.; Durand, N.

    1998-04-01

    Elastic properties of multilayers with low period thickness show in some cases anomalies which are generally correlated with structural modifications in individual layers. In the recent past, several studies have evidenced using X-ray diffraction in-plane and out-of-plane strains with the same sign. Some authors have then proposed in the case of W/Ni and Nb/Cu metallic superlattices to use a negative Poisson's ratio. This result is surprising because the value of this coefficient in metals is generally positive. In this article, we introduce a novel interpretation mainly based on the experimental determination by sin^2Psi method of the reference parameter (stress-free lattice parameter) used in strain calculations. Then, we show that the introduction of the bulk parameter instead of stress-free parameter for the reference parameter is an unrealistic assumption in the case of thin films and multilayers (W and Ag/Ni) and may thus lead to wrong results which are then in total disagreement with those obtained by other techniques. Therefore, the elastic anomaly concerning Poisson's ratio which has been reported by some authors in scientific literature do not result from real structure of multilayers but from experimental X-ray diffraction data analysis. Les propriétés élastiques dans certains systèmes multicouches de faible période présentent des anomalies qui sont généralement associées à des modifications des propriétés structurales de chacune des couches. Ainsi, plusieurs études ont mis en évidence par diffraction des rayons X des déformations de même signe dans le plan et selon la normale au plan des couches déposées. Certains auteurs ont alors proposé dans le cas de systèmes métalliques W/Ni et Nb/Cu l'utilisation d'un coefficient de Poisson négatif. Ce résultat est surprenant car la valeur de ce coefficient pour les métaux est généralement positive. Dans cet article, nous présentons une nouvelle interprétation reposant sur la d

  2. Life Event, Stress and Illness

    PubMed Central

    Salleh, Mohd. Razali

    2008-01-01

    The relationship between stress and illness is complex. The susceptibility to stress varies from person to person. Among the factors that influenced the susceptibility to stress are genetic vulnerability, coping style, type of personality and social support. Not all stress has negative effect. Studies have shown that short-term stress boosted the immune system, but chronic stress has a significant effect on the immune system that ultimately manifest an illness. It raises catecholamine and suppressor T cells levels, which suppress the immune system. This suppression, in turn raises the risk of viral infection. Stress also leads to the release of histamine, which can trigger severe broncho-constriction in asthmatics. Stress increases the risk for diabetes mellitus, especially in overweight individuals, since psychological stress alters insulin needs. Stress also alters the acid concentration in the stomach, which can lead to peptic ulcers, stress ulcers or ulcerative colitis. Chronic stress can also lead to plaque buildup in the arteries (atherosclerosis), especially if combined with a high-fat diet and sedentary living. The correlation between stressful life events and psychiatric illness is stronger than the correlation with medical or physical illness. The relationship of stress with psychiatric illness is strongest in neuroses, which is followed by depression and schizophrenia. There is no scientific evidence of a direct cause-and-effect relationship between the immune system changes and the development of cancer. However, recent studies found a link between stress, tumour development and suppression of natural killer (NK) cells, which is actively involved in preventing metastasis and destroying small metastases. PMID:22589633

  3. Scleroderma, Stress and CAM Utilization

    PubMed Central

    Johnston, Michael Francis; Brodsky, Marc; Tafur, Joe; Kim Ho, Mai

    2009-01-01

    Scleroderma is an autoimmune disease influenced by interplay among genetic and environmental factors, of which one is stress. Complementary and alternative medicine (CAM) is frequently used to treat stress and those diseases in which stress has been implicated. Results are presented from a survey of patients with scleroderma. Respondents were a convenient sample of those attending a national conference in Las Vegas in 2002. Findings implicate stress in the onset, continuation and exacerbation of scleroderma. The implication is that CAM providers may be filling an important patient need in their provision of services that identify and treat stress and its related disorders. PMID:18955259

  4. Antiferromagnetic character of workplace stress

    NASA Astrophysics Data System (ADS)

    Watanabe, Jun-Ichiro; Akitomi, Tomoaki; Ara, Koji; Yano, Kazuo

    2011-07-01

    We study the nature of workplace stress from the aspect of human-human interactions. We investigated the distribution of Center for Epidemiological Studies Depression Scale scores, a measure of the degree of stress, in workplaces. We found that the degree of stress people experience when around other highly stressed people tends to be low, and vice versa. A simulation based on a model describing microlevel human-human interaction reproduced this observed phenomena and revealed that the energy state of a face-to-face communication network correlates with workplace stress macroscopically.

  5. Harold Goldstein (R) and Dan Leiser (L) discuss bone implant development in the the Shuttle Tile

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Harold Goldstein (R) and Dan Leiser (L) discuss bone implant development in the the Shuttle Tile Laboratory N-242. A spin-off of Ames research on both bone density in microgravity and on thermal protection foams is the bone-growth implant shown in 1993.

  6. Southwest Research Institute astronomer Dan Durda checks the alignment of the SWUIS-A Xybion digital

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Southwest Research Institute astronomer Dan Durda checks the alignment of the SWUIS-A Xybion digital camera mounted in the rear cockpit of a NASA Dryden F/A-18B before taking off on an astronomy mission to search for small vulcanoids (asteroids) that may be orbiting between the sun and the planet Mercury.

  7. An Interview with Dan Hallahan: From Clinical Researcher to Consummate Teacher Educator

    ERIC Educational Resources Information Center

    Sayeski, Kristin L.

    2014-01-01

    Kristin L. Sayeski introduces the reader to Dan Hallahan and provides a synopsis of his educational background. She reports Hallahan received his BA in psychology in 1967 and his PhD in education and psychology in 1971 from the University of Michigan, then began his career as an assistant professor in special education at the University of…

  8. Seeding Stress Resilience through Inoculation

    PubMed Central

    Ashokan, Archana; Sivasubramanian, Meenalochani; Mitra, Rupshi

    2016-01-01

    Stress is a generalized set of physiological and psychological responses observed when an organism is placed under challenging circumstances. The stress response allows organisms to reattain the equilibrium in face of perturbations. Unfortunately, chronic and/or traumatic exposure to stress frequently overwhelms coping ability of an individual. This is manifested as symptoms affecting emotions and cognition in stress-related mental disorders. Thus environmental interventions that promote resilience in face of stress have much clinical relevance. Focus of the bulk of relevant neurobiological research at present remains on negative aspects of health and psychological outcomes of stress exposure. Yet exposure to the stress itself can promote resilience to subsequent stressful episodes later in the life. This is especially true if the prior stress occurs early in life, is mild in its magnitude, and is controllable by the individual. This articulation has been referred to as “stress inoculation,” reminiscent of resilience to the pathology generated through vaccination by attenuated pathogen itself. Using experimental evidence from animal models, this review explores relationship between nature of the “inoculum” stress and subsequent psychological resilience. PMID:26881112

  9. L'atteinte osseuse dans le sarcome de Kaposi classique et agressif: à propos d'un cas

    PubMed Central

    Sbiyaa, Mouhcine; El Alaoui, Adil; El Bardai, Mohammed; Mezzani, Amine; Lahrach, Kamal; Marzouki, Amine; Boutayeb, Fawzi

    2016-01-01

    Le sarcome de Kaposi classique est une tumeur rare multifocale d'origine des cellules endothéliales vasculaires à caractère évolutif progressif et peu maligne. L'atteinte viscérale dans le sarcome de kaposi est parfois observée chez les patients VIH positif par contre la dissémination tumorale dans les ganglions lymphatiques viscérales dans le SK classique reste très rare. On rapporte un cas rare de sarcome de kaposi classique agressif de la main avec une évolution rapide et destructive. PMID:27347285

  10. Particle stress and viscous compaction

    SciTech Connect

    Prasad, D.; Kytoemaa, H.K.

    1994-12-31

    This study describes the transition between the quasi-static and the viscous regimes of shearing of thin layers of spheres in a viscous fluid at high solid loadings. Experiments were conducted in a Couette-type shear cell in two complementary modes: (a) constant particle normal stress, variable solid fraction and (b) constant solid fraction, variable particle normal stress. In steady shearing under the constraint of constant solid fraction, transition from a strain rate independent stress to a linearly dependent on was found to occur with a local minimum in the stresses with respect to strain rage; correspondingly, the solid fraction assumed a maximum with respect to strain rate under conditions of constant normal stress. At sufficiently high strain rates, the mixture exhibited a linear Newtonian-like scaling between strain rate and both shear and normal stresses. These measurements of normal stress are the first since those of Bagnold (1954).

  11. The surgically induced stress response.

    PubMed

    Finnerty, Celeste C; Mabvuure, Nigel Tapiwa; Ali, Arham; Kozar, Rosemary A; Herndon, David N

    2013-09-01

    The stress response to surgery, critical illness, trauma, and burns encompasses derangements of metabolic and physiological processes that induce perturbations in the inflammatory, acute phase, hormonal, and genomic responses. Hypermetabolism and hypercatabolism result, leading to muscle wasting, impaired immune function and wound healing, organ failure, and death. The surgery-induced stress response is largely similar to that triggered by traumatic injuries; the duration of the stress response, however, varies according to the severity of injury (surgical or traumatic). This spectrum of injuries and insults ranges from small lacerations to severe insults such as large poly-traumatic and burn injuries. Burn injuries provide an extreme model of trauma induced stress responses that can be used to study the long-term effects of a prolonged stress response. Although the stress response to acute trauma evolved to confer improved chances of survival following injury, in modern surgical practice the stress response can be detrimental. PMID:24009246

  12. Quantifying Residual Stresses by Means of Thermoelastic Stress Analysis

    NASA Technical Reports Server (NTRS)

    Gyekenyesi, Andrew L.; Baaklini, George Y.

    2001-01-01

    This study focused on the application of the Thermoelastic Stress Analysis (TSA) technique as a tool for assessing the residual stress state of structures. TSA is based on the fact that materials experience small temperature changes when compressed or expanded. When a structure is cyclically loaded, a surface temperature profile results which correlates to the surface stresses. The cyclic surface temperature is measured with an infrared camera. Traditionally, the amplitude of a TSA signal was theoretically defined to be linearly dependent on the cyclic stress amplitude. Recent studies have established that the temperature response is also dependent on the cyclic mean stress (i.e., the static stress state of the structure). In a previous study by the authors, it was shown that mean stresses significantly influenced the TSA results for titanium- and nickel-based alloys. This study continued the effort of accurate direct measurements of the mean stress effect by implementing various experimental modifications. In addition, a more in-depth analysis was conducted which involved analyzing the second harmonic of the temperature response. By obtaining the amplitudes of the first and second harmonics, the stress amplitude and the mean stress at a given point on a structure subjected to a cyclic load can be simultaneously obtained. The experimental results showed good agreement with the theoretical predictions for both the first and second harmonics of the temperature response. As a result, confidence was achieved concerning the ability to simultaneously obtain values for the static stress state as well as the cyclic stress amplitude of structures subjected to cyclic loads using the TSA technique. With continued research, it is now feasible to establish a protocol that would enable the monitoring of residual stresses in structures utilizing TSA.

  13. Neuropeptide Y: A stressful review

    PubMed Central

    Reichmann, Florian; Holzer, Peter

    2016-01-01

    Stress is defined as an adverse condition that disturbs the homeostasis of the body and activates adaptation responses. Among the many pathways and mediators involved, neuropeptide Y (NPY) stands out due to its unique stress-relieving, anxiolytic and neuroprotective properties. Stress exposure alters the biosynthesis of NPY in distinct brain regions, the magnitude and direction of this effect varying with the duration and type of stress. NPY is expressed in particular neurons of the brainstem, hypothalamus and limbic system, which explains why NPY has an impact on stress-related changes in emotional-affective behaviour and feeding as well as on stress coping. The biological actions of NPY in mammals are mediated by the Y1, Y2, Y4 and Y5 receptor, Y1 receptor stimulation being anxiolytic whereas Y2 receptor activation is anxiogenic. Emerging evidence attributes NPY a role in stress resilience, the ability to cope with stress. Thus there is a negative correlation between stress-induced behavioural disruption and cerebral NPY expression in animal models of post-traumatic stress disorder. Exogenous NPY prevents the negative consequences of stress, and polymorphisms of the NPY gene are predictive of impaired stress processing and increased risk of neuropsychiatric diseases. Stress is also a factor contributing to, and resulting from, neurodegenerative diseases such as Alzheimer’s, Parkinson’s and Huntington’s disease, in which NPY appears to play an important neuroprotective role. This review summarizes the evidence for an implication of NPY in stress-related and neurodegenerative pathologies and addresses the cerebral NPY system as a therapeutic target. PMID:26441327

  14. Simulation numérique d'écoulement compressible dans les joints labyrinthe

    NASA Astrophysics Data System (ADS)

    Sriti, M.; Agouzoul, M.; Ouazar, D.; Micheau, P.

    1997-05-01

    The labyrinth seals are the devices used machines which serve to restrict the leakages crossing a carter (or stator) by a rotating shaft (or rotor) and to avoid the important friction to high rotation speeds. These devices, which in addition behave as shaft bearings, can modify the dynamics characteristics of the line of the shaft in which they are integrated. The present work has been carried out with the purpose of controlling better the flows within the labyrinth seals and to determine their static (leakage-pressure) and dynamic (stiffness and damping coefficients) characteristics. It's based on the development of a global numerical model, and on the integration of the obtained correlations by 3D axisymmetric computation in this model. Les joints labyrinthe sont des dispositifs utilisés dans les machines, ils servent à limiter les fuites à la traversée d'un carter (ou stator) par un arbre tournant (ou rotor) et éviter le frottement important aux vitesses de rotation élevées. Ces dispositifs, qui de plus, se comportent comme des paliers, peuvent modifier les caractéristiques dynamiques de la ligne d'arbre dans laquelle ils sont intégrés. Le travail présenté a été effectué dans le but de mieux maîtriser les écoulements dans les joints labyrinthe et de déterminer leurs caractéristiques statiques (débit-pression) et dynamiques (coefficients de raideur et d'amortissement). Il s'appuie sur le développement d'outils numériques intégrant dans les calculs globaux des résultats de calculs locaux (3D axisymétriques).

  15. Stress and distress.

    PubMed

    Selye, H

    1975-12-01

    I must ask the reader's indulgence for this article's concern with applications of the stress concept, which are distinct from, although related to clinical medicine. It has not been my object to deal with the way physicians have been aided by stress research in the practice of medicine--that information is already widely available. Rather, I have attempted to sketch briefly the history of the stress theory and to demonstrate how this information can help anyone, physician or layman, lead a more complete and satisfying life. The applications of the stress theory have been dealt with at length elsewhere. I believe that we can find within scientifically verified observations the basis of a code of behavior suited to our century. The great laws of nature that regulate the defenses of living beings against stress of any kind are essentially the same at all levels of life, from individual cells to entire complex human organisms and societies. It helps a great deal to understand the fundamental advantages and disadvantages of catatoxic and syntoxic attitudes by studying the biologic basis of self-preservation as reflected in syntoxic and catatoxic chemical mechanisms. When applied to everyday problems, this understanding should lead to choices most likely to provide us the pleasant eustress (from the Greek eu meaning good, as in euphoria) involved in achieving fulfillment and victory, thereby avoiding the self-destructive distress of frustration and failure. So the translation of the laws governing resistance of cells and organs to a code of behavior comes down to three basic precepts: 1. Find your own natural stress level. People differ with regard to the amount and kind of work they consider worth doing to meet the exigencies of daily life and to assure their future security and happiness. In this respect, all of us are influenced by hereditary predispositions and the expectations of our society. Only through planned self-analysis can we establish what we really want

  16. Europa Under Stress

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This high resolution image of the icy plains on Europa shows multiple sets of cross-cutting ridges. Many of these ridges are cut by younger fractures. Fractures that display relative motion are known as faults; several faults showing horizontal motion, like the San Andreas Fault in California, are seen here.

    Faults and ridges give planetary geologists clues to the stresses within the crust at the time of formation. Ridges typically form as a result of compression. The orientation of the compressive stress is perpendicular to the strike (long axis) of the ridge. In contrast, fractures form as a result of tensional stresses that crack the brittle crust. These features indicate that the surface of Europa has experienced repeated episodes of tension and compression throughout its history.

    This image is approximately 12 kilometers (7 miles) by 15 kilometers (9 miles) across, centered near 15N, 273W. The Galileo spacecraft obtained this image on February 20, 1997 during its sixth orbit of Jupiter from a distance of 2000 kilometers (1240 miles). North is toward the top of the image, with the sun illuminating the surface from the right.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  17. Earthquake Apparent Stress Scaling

    NASA Astrophysics Data System (ADS)

    Mayeda, K.; Walter, W. R.

    2003-04-01

    There is currently a disagreement within the geophysical community on the way earthquake energy scales with magnitude. One set of recent papers finds evidence that energy release per seismic moment (apparent stress) is constant (e.g. Choy and Boatwright, 1995; McGarr, 1999; Ide and Beroza, 2001). Another set of recent papers finds the apparent stress increases with magnitude (e.g. Kanamori et al., 1993 Abercrombie, 1995; Mayeda and Walter, 1996; Izutani and Kanamori, 2001). The resolution of this issue is complicated by the difficulty of accurately accounting for and determining the seismic energy radiated by earthquakes over a wide range of event sizes in a consistent manner. We have just started a project to reexamine this issue by applying the same methodology to a series of datasets that spans roughly 10 orders in seismic moment, M0. We will summarize recent results using a coda envelope methodology of Mayeda et al, (2003) which provide the most stable source spectral estimates to date. This methodology eliminates the complicating effects of lateral path heterogeneity, source radiation pattern, directivity, and site response (e.g., amplification, f-max and kappa). We find that in tectonically active continental crustal areas the total radiated energy scales as M00.25 whereas in regions of relatively younger oceanic crust, the stress drop is generally lower and exhibits a 1-to-1 scaling with moment. In addition to answering a fundamental question in earthquake source dynamics, this study addresses how one would scale small earthquakes in a particular region up to a future, more damaging earthquake. This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.

  18. Exploring family physician stress

    PubMed Central

    Lee, F. Joseph; Brown, Judith Belle; Stewart, Moira

    2009-01-01

    ABSTRACT OBJECTIVE To explore the nature of professional stress and the strategies used by family physicians to deal with this stress. DESIGN Qualitative study. SETTING Kitchener-Waterloo, Ont. PARTICIPANTS Ten key-informant family physicians. METHODS In-depth interviews were conducted with key informants. A total of 40 key informants were identified, based on selected criteria; 24 provided consent. The potential participants were rank-ordered for interviews to provide maximum variation in age, sex, and years in practice. Interviews were conducted, audiotaped, transcribed verbatim, and analyzed until thematic saturation was reached, as determined through an iterative process. This occurred after 10 in-depth interviews. Immersion and crystallization techniques were used. MAIN FINDINGS The participants described professional stresses and strategies at the personal, occupational, and health care system levels. Personal stressors included personality traits and the need to balance family and career, which were countered by biological, psychological, social, and spiritual strategies. Occupational stressors included challenging patients, high workload, time limitations, competency issues, challenges of documentation and practice management, and changing roles within the workplace. Occupational stressors were countered by strategies such as setting limits, participating in continuing medical education, soliciting support from colleagues and staff, making use of teams, improving patient-physician relationships, exploring new forms of remuneration, and scheduling appropriately. Stressors affecting the wider health care system included limited resources, imposed rules and regulations, lack of support from specialists, feeling undervalued, and financial concerns. CONCLUSION Family physicians face a multitude of challenges at personal, occupational, and health care system levels. A systems approach provides a new framework in which proactive strategies can augment more than

  19. UV, stress and aging.

    PubMed

    Debacq-Chainiaux, Florence; Leduc, Cedric; Verbeke, Alix; Toussaint, Olivier

    2012-07-01

    Skin is a model of choice in studies on aging. Indeed, skin aging can be modulated by internal and external factors, reflecting its complexity. Two types of skin aging have been identified: intrinsic, mainly genetically determined and extrinsic-also called "photo-aging"-resulting on the impact of environmental stress and more precisely of UV rays. Simplified in vitro models, based on cellular senescence, have been developed to study the relationship between UV and aging. These models vary on the cell type (fibroblasts or keratinocytes, normal or immortalized) and the type of UV used (UVA or UVB). PMID:23467762

  20. Heat Stress Monitor

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The heavy, cumbersome body protection suits worn by members of hazardous materials response teams cause marked elevation of body temperatures, which can reduce effectiveness and lead to heat stress and injury. The CorTemp System, marketed by Human Technologies, Inc., provides the basis for a body temperature monitoring alarm system. Encased in a three-quarter-inch ingestible capsule, the system includes a mini-thermometer, miniature telemetry system, a microbattery and temperature sensor. It makes its way through the digestive system, continuously monitoring temperature. Findings are sent to the recorder by telemetry, and then displayed and stored for transfer to a computer.

  1. Stress intensity factors

    SciTech Connect

    Erdogan, F.

    1983-12-01

    In this work the concept of the stress intensity factor, the underlying mechanics problem leading to its emergence, and its physical relevance, particularly its relation to fracture mechanics are discussed. The reasons as to why it has become nearly an indispensable tool for studying such important phenomena as brittle fracture and fatigue or corrosion fatigue crack propagation in structural solids are considered. A brief discussion of some of the important methods of solution of elastic crack problems is given. Also, a number of related special mechanics problems are described. 24 references.

  2. Stress Prediction System

    NASA Technical Reports Server (NTRS)

    1995-01-01

    NASA wanted to know how astronauts' bodies would react under various gravitational pulls and space suit weights. Under contract to NASA, the University of Michigan's Center for Ergonomics developed a model capable of predicting what type of stress and what degree of load a body could stand. The algorithm generated was commercialized with the ISTU (Isometric Strength Testing Unit) Functional Capacity Evaluation System, which simulates tasks such as lifting a heavy box or pushing a cart and evaluates the exertion expended. It also identifies the muscle group that limits the subject's performance. It is an effective tool of personnel evaluation, selection and job redesign.

  3. Flow stress of copper

    SciTech Connect

    Pedersen, O.B.

    1987-10-01

    The reverse microflow associated with the Bauschinger effect in copper strained into stage II is characterized experimentally and analyzed in terms of the theory of obstacle-controlled flow and established composite theory. The results are discussed in the light of observations by electron microscopy, deformation calorimetry and X-ray diffraction. It is suggested that the overall flow resistance arises from an interplay of two modes of obstacle controlled glide, none of which dominate the flow stress. One mode occurs inside regions of high local dislocation density (inclusions) where individual forest dislocations oppose glide on the primary slip system. The second mode is bowing of dislocations between the inclusions.

  4. Evaluation of Stress Levels of Professionals.

    ERIC Educational Resources Information Center

    Schnorr, Janet K.; McWilliams, Jettie M.

    This study was conducted to analyze levels and areas of stress of professionals in selected service professions and to establish national norms of stress for these professions. The 60-item Tennessee Stress Scale-R (TSS-R) is a work-related stress inventory for professionals which provides a measure of stress in three areas: stress producers,…

  5. Managing Anxiety and Stress. Second Edition.

    ERIC Educational Resources Information Center

    Archer, James, Jr.

    This self-help book provides information about stress and stress management. The first part focuses on awareness of stress. A number of activities are included to help the individual understand and analyze stress reactions. Information is provided about stressors, performance stress, cumulative stress, and several other aspects of stress…

  6. Lexical Stress Assignment in Italian Developmental Dyslexia

    ERIC Educational Resources Information Center

    Paizi, Despina; Zoccolotti, Pierluigi; Burani, Cristina

    2011-01-01

    Stress assignment to Italian polysyllabic words is unpredictable, because stress is neither marked nor predicted by rule. Stress assignment, especially to low frequency words, has been reported to be a function of stress dominance and stress neighbourhood. Two experiments investigate stress assignment in sixth-grade, skilled and dyslexic, readers.…

  7. Corrosion Product Film-Induced Stress Facilitates Stress Corrosion Cracking.

    PubMed

    Wang, Wenwen; Zhang, Zhiliang; Ren, Xuechong; Guan, Yongjun; Su, Yanjing

    2015-01-01

    Finite element analyses were conducted to clarify the role of corrosion product films (CPFs) in stress corrosion cracking (SCC). Flat and U-shaped edge-notched specimens were investigated in terms of the CPF-induced stress in the metallic substrate and the stress in the CPF. For a U-shaped edge-notched specimen, the stress field in front of the notch tip is affected by the Young's modulus of the CPF and the CPF thickness and notch geometry. The CPF-induced tensile stress in the metallic substrate is superimposed on the applied load to increase the crack tip strain and facilitate localized plasticity deformation. In addition, the stress in the CPF surface contributes to the rupture of the CPFs. The results provide physical insights into the role of CPFs in SCC. PMID:26066367

  8. Stress among charge nurses: tool development and stress measurement.

    PubMed

    Admi, Hanna; Moshe-Eilon, Yael

    2010-01-01

    The aim of this study was to develop and implement a tool for measuring the role stress of charge nurses. Tools are lacking regarding measurement of nursing role stressors, particularly for charge nurses. Based on focus groups and in-depth interviews with charge nurses within a large tertiary hospital, a charge nurse stress questionnaire was developed which measures six factors of stress: authority-responsibility conflict, patient-nurse interaction, deficient resources, managerial decision making, role conflict, and overload. The prominent stressors on charge nurses were specific to the role. Mean levels of stress were significantly higher for nurses who attended post-graduate clinical courses than for those who did not. The mean level of stress was higher for department nurse managers than for nurses without a managerial position. This tool was designed to measure charge nurse stress demonstrates reliability, and highlights the specific stressors demanded by the role. Preparation and ongoing support for fulfilling this position are recommended. PMID:20672537

  9. Corrosion Product Film-Induced Stress Facilitates Stress Corrosion Cracking

    PubMed Central

    Wang, Wenwen; Zhang, Zhiliang; Ren, Xuechong; Guan, Yongjun; Su, Yanjing

    2015-01-01

    Finite element analyses were conducted to clarify the role of corrosion product films (CPFs) in stress corrosion cracking (SCC). Flat and U-shaped edge-notched specimens were investigated in terms of the CPF-induced stress in the metallic substrate and the stress in the CPF. For a U-shaped edge-notched specimen, the stress field in front of the notch tip is affected by the Young’s modulus of the CPF and the CPF thickness and notch geometry. The CPF-induced tensile stress in the metallic substrate is superimposed on the applied load to increase the crack tip strain and facilitate localized plasticity deformation. In addition, the stress in the CPF surface contributes to the rupture of the CPFs. The results provide physical insights into the role of CPFs in SCC. PMID:26066367

  10. Vasopressin and oxytocin in stress.

    PubMed

    Jezova, D; Skultetyova, I; Tokarev, D I; Bakos, P; Vigas, M

    1995-12-29

    Though oxytocin and vasopressin are similar in structure and are produced in the same brain regions, they show specific responses under stress conditions. In humans, increases in peripheral blood vasopressin appear to be a consistent finding during many acute stress situations, while in rats, vasopressin secretion is unresponsive to several stimuli known to induce ACTH and catecholamine release. Even decreases in vasopressin levels during stress were described. In accordance with others, we observed enhanced vasopressin release in response to stress stimuli with an osmotic component such as hypertonic saline injection but also during exposure of rats to a warm environment. Immobilization stress which fails to induce vasopressin release was reported to increase hypothalamic vasopressin mRNA and plasma vasopressin levels in chronically adreno-demedullated rats. Unlike vasopressin, oxytocin may be considered a typical stress hormone responding to osmotic as well as other stress stimuli. We found that acute exposure of rats to immobilization stress resulted in an increase in oxytocin mRNA level. In addition, we have shown that magnocellular neurons of the paraventricular nucleus, but not the supraoptic nucleus, are essential for oxytocin release during immobilization stress. The release of posterior pituitary hormones represents an important component of the stress response. PMID:8597399

  11. Stress induced obesity: lessons from rodent models of stress

    PubMed Central

    Patterson, Zachary R.; Abizaid, Alfonso

    2013-01-01

    Stress was once defined as the non-specific result of the body to any demand or challenge to homeostasis. A more current view of stress is the behavioral and physiological responses generated in the face of, or in anticipation of, a perceived threat. The stress response involves activation of the sympathetic nervous system and recruitment of the hypothalamic-pituitary-adrenal (HPA) axis. When an organism encounters a stressor (social, physical, etc.), these endogenous stress systems are stimulated in order to generate a fight-or-flight response, and manage the stressful situation. As such, an organism is forced to liberate energy resources in attempt to meet the energetic demands posed by the stressor. A change in the energy homeostatic balance is thus required to exploit an appropriate resource and deliver useable energy to the target muscles and tissues involved in the stress response. Acutely, this change in energy homeostasis and the liberation of energy is considered advantageous, as it is required for the survival of the organism. However, when an organism is subjected to a prolonged stressor, as is the case during chronic stress, a continuous irregularity in energy homeostasis is considered detrimental and may lead to the development of metabolic disturbances such as cardiovascular disease, type II diabetes mellitus and obesity. This concept has been studied extensively using animal models, and the neurobiological underpinnings of stress induced metabolic disorders are beginning to surface. However, different animal models of stress continue to produce divergent metabolic phenotypes wherein some animals become anorexic and lose body mass while others increase food intake and body mass and become vulnerable to the development of metabolic disturbances. It remains unclear exactly what factors associated with stress models can be used to predict the metabolic outcome of the organism. This review will explore a variety of rodent stress models and discuss the

  12. Preimplantation Stress and Development

    PubMed Central

    Feuer, Sky; Rinaudo, Paolo

    2013-01-01

    The developmental origins of health and disease hypothesis holds that inappropriate environmental cues in utero, a period marked by tremendous developmental sensitivity, facilitate cellular reprogramming to ultimately predispose disease in adulthood. In this review, we analyze if stress during early stages of development can affect future health. This has wide clinical importance, given that 5 million children have been conceived with assisted reproductive technologies (ART). Because the primary outcome of assisted reproduction procedures is delivery at term of a live, healthy baby, the postnatal effects occurring outside of the neonatal period are often overlooked. To this end, the long-term outcome of ART is appropriately the most relevant concern of the field today. Evidence of adverse consequences is controversial. The majority of studies have concluded no obvious problems in IVF-conceived children, although a number of isolated cases of imprinted diseases, cancers, or malformations have been reported. Given that animal studies suggest alteration of metabolic pathways following preimplantation stress, it will be of great importance to follow-up ART individuals as they enter later stages of adult life. PMID:24203919

  13. Oxidative Stress in Myopia

    PubMed Central

    Francisco, Bosch-Morell; Salvador, Mérida; Amparo, Navea

    2015-01-01

    Myopia affected approximately 1.6 billion people worldwide in 2000, and it is expected to increase to 2.5 billion by 2020. Although optical problems can be corrected by optics or surgical procedures, normal myopia and high myopia are still an unsolved medical problem. They frequently predispose people who have them to suffer from other eye pathologies: retinal detachment, glaucoma, macular hemorrhage, cataracts, and so on being one of the main causes of visual deterioration and blindness. Genetic and environmental factors have been associated with myopia. Nevertheless, lack of knowledge in the underlying physiopathological molecular mechanisms has not permitted an adequate diagnosis, prevention, or treatment to be found. Nowadays several pieces of evidence indicate that oxidative stress may help explain the altered regulatory pathways in myopia and the appearance of associated eye diseases. On the one hand, oxidative damage associated with hypoxia myopic can alter the neuromodulation that nitric oxide and dopamine have in eye growth. On the other hand, radical superoxide or peroxynitrite production damage retina, vitreous, lens, and so on contributing to the appearance of retinopathies, retinal detachment, cataracts and so on. The objective of this review is to suggest that oxidative stress is one of the key pieces that can help solve this complex eye problem. PMID:25922643

  14. Stress, Aging and Thirst

    NASA Technical Reports Server (NTRS)

    Greenleaf, John E.

    1998-01-01

    After growth during adolesence, total body water decreases progressively with aging from 65% of body weight to about 53% of body weight in the 70th decade; a majority of the loss occurs from the extracellular volume, from 42% to about 25%, respectively. Cellular volume also reaches equilibrium in the 70th decade at about 25% of body weight. Various stresses such as exercise, heat and attitude exposure, ad prior dehydration attenuate voluntary fluid intake (involuntary dehydration). Voluntary fluid intake appears to decrease with aging (involuntary dehydration in this sense aging can be considered as a stress. Kidney function and muscle mass (80% water) decrease somewhat with aging, and voluntary fluid intake (thirst) is also attenuated. Thirst is stimulated by increasing osmolality (hypernatremia) of the extracellular fluid and by decreased extracellular volume (mainly plasma volume) which act to increase intracellular fluid volume osmolality to activiate drinking. The latter decreases fluid compartment osmolality which ' It terminates drinking. However, this drinking mechanism seems to be attenuated with aging such that increasing plasma osmolality no longer stimulates fluid intake appropriately. Hypernatremia in the elderly has been associated all too frequently with greater incidence of bacterial infection and increased mortality. Involuntary dehydration can be overcome in young men by acclimation to an intermittent exercise-in-heat training program. Perhaps exercise training in the elderly would also increase voluntary fluid intake and increase muscle mass to enhance retention of water.

  15. Stress fractures in athletes.

    PubMed

    Hulkko, A; Orava, S

    1987-06-01

    During the 14-year period of 1971-1985, 368 stress fractures in 324 athletes were treated. The series contained 268 fractures in males and 100 fractures in females; 32 fractures occurred in children (less than 16 years), 117 in adolescents (16-19 years), and 219 in adults. Forty-six fractures were incurred by athletes at an international level, 274 by athletes at a national or district level and 48 by recreational athletes. Of the total cases, 72% occurred to runners and a further 12% to athletes in other sports after running exercises. The distribution of the stress fractures by site was: tibia 182, metatarsal bones 73, fibula 44, big toe sesamoid bones 15, femoral shaft 14, femoral neck 9, tarsal navicular 9, pelvis 7, olecranon 5 and other bones 10. Of the total fractures, 342 were treated conservatively and 26 fractures required surgical treatment. The operative indication was dislocation in 5 cases and delayed union/nonunion in 21 cases. The sites most often affected by delayed union were: anterior midtibia, sesamoid bones of the big toe, base of the fifth metatarsal, olecranon, and tarsal navicular. The athletes at an international level experienced the greatest risk of multiple separate fractures, protracted healing, or fractures requiring surgery. PMID:3623785

  16. Medial tibial stress syndrome.

    PubMed

    Reshef, Noam; Guelich, David R

    2012-04-01

    MTSS is a benign, though painful, condition, and a common problem in the running athlete. It is prevalent among military personnel, runners, and dancers, showing an incidence of 4% to 35%. Common names for this problem include shin splints, soleus syndrome, tibial stress syndrome, and periostitis. The exact cause of this condition is unknown. Previous theories included an inflammatory response of the periosteum or periosteal traction reaction. More recent evidence suggests a painful stress reaction of bone. The most proven risk factors are hyperpronation of the foot, female sex, and history of previous MTSS. Patient evaluation is based on meticulous history taking and physical examination. Even though the diagnosis remains clinical, imaging studies, such as plain radiographs and bone scans are usually sufficient, although MRI is useful in borderline cases to rule out more significant pathology. Conservative treatment is almost always successful and includes several options; though none has proven more superior to rest. Prevention programs do not seem to influence the rate of MTSS, though shock-absorbing insoles have reduced MTSS rates in military personnel, and ESWT has shortened the duration of symptoms. Surgery is rarely indicated but has shown some promising results in patients who have not responded to all conservative options. PMID:22341017

  17. A Molecular Web: Endoplasmic Reticulum Stress, Inflammation, and Oxidative Stress

    PubMed Central

    Chaudhari, Namrata; Talwar, Priti; Parimisetty, Avinash; Lefebvre d’Hellencourt, Christian; Ravanan, Palaniyandi

    2014-01-01

    Execution of fundamental cellular functions demands regulated protein folding homeostasis. Endoplasmic reticulum (ER) is an active organelle existing to implement this function by folding and modifying secretory and membrane proteins. Loss of protein folding homeostasis is central to various diseases and budding evidences suggest ER stress as being a major contributor in the development or pathology of a diseased state besides other cellular stresses. The trigger for diseases may be diverse but, inflammation and/or ER stress may be basic mechanisms increasing the severity or complicating the condition of the disease. Chronic ER stress and activation of the unfolded-protein response (UPR) through endogenous or exogenous insults may result in impaired calcium and redox homeostasis, oxidative stress via protein overload thereby also influencing vital mitochondrial functions. Calcium released from the ER augments the production of mitochondrial Reactive Oxygen Species (ROS). Toxic accumulation of ROS within ER and mitochondria disturbs fundamental organelle functions. Sustained ER stress is known to potentially elicit inflammatory responses via UPR pathways. Additionally, ROS generated through inflammation or mitochondrial dysfunction could accelerate ER malfunction. Dysfunctional UPR pathways have been associated with a wide range of diseases including several neurodegenerative diseases, stroke, metabolic disorders, cancer, inflammatory disease, diabetes mellitus, cardiovascular disease, and others. In this review, we have discussed the UPR signaling pathways, and networking between ER stress-induced inflammatory pathways, oxidative stress, and mitochondrial signaling events, which further induce or exacerbate ER stress. PMID:25120434

  18. Residual stress effects in stress-corrosion cracking

    SciTech Connect

    Toribio, J.

    1998-04-01

    This paper describes a wide variety of residual stress effects in stress-corrosion cracking (SCC) of metallic materials on the basis of previous research of the author on high-strength steel in the form of hot-rolled bars and cold-drawn wires for prestressed concrete. It is seen that internal residual stress fields in the material play a very important -- if not decisive -- role in the SCC behavior of any engineering material, especially residual stresses generated near the free surface or in the vicinity of a crack tip.

  19. Stress discourse and Western biomedical ideology: rewriting stress.

    PubMed

    Donnelly, Tam T; Long, Bonita C

    2003-06-01

    Popular psychosocial theories of stress and coping are based on an empiricist paradigm and a Western biomedical framework that reflect Western ideologies and values about health and illness. Problems associated with this discourse lie mainly in the ideologies that emphasize naturalism, individualism, rationalism, and objectivity. We suggest that stress and coping theory should be concerned with the ways in which power relations and social institutions produce the meaning of stress. The inclusion of alternative discourses that attend to the micro and macro social and historical factors is necessary for the further development of stress and coping theory and practice. PMID:12746181

  20. Hyperglycemic Stress and Carbon Stress in Diabetic Glucotoxicity

    PubMed Central

    Luo, Xiaoting; Wu, Jinzi; Jing, Siqun; Yan, Liang-Jun

    2016-01-01

    Diabetes and its complications are caused by chronic glucotoxicity driven by persistent hyperglycemia. In this article, we review the mechanisms of diabetic glucotoxicity by focusing mainly on hyperglycemic stress and carbon stress. Mechanisms of hyperglycemic stress include reductive stress or pseudohypoxic stress caused by redox imbalance between NADH and NAD+ driven by activation of both the polyol pathway and poly ADP ribose polymerase; the hexosamine pathway; the advanced glycation end products pathway; the protein kinase C activation pathway; and the enediol formation pathway. Mechanisms of carbon stress include excess production of acetyl-CoA that can over-acetylate a proteome and excess production of fumarate that can over-succinate a proteome; both of which can increase glucotoxicity in diabetes. For hyperglycemia stress, we also discuss the possible role of mitochondrial complex I in diabetes as this complex, in charge of NAD+ regeneration, can make more reactive oxygen species (ROS) in the presence of excess NADH. For carbon stress, we also discuss the role of sirtuins in diabetes as they are deacetylases that can reverse protein acetylation thereby attenuating diabetic glucotoxicity and improving glucose metabolism. It is our belief that targeting some of the stress pathways discussed in this article may provide new therapeutic strategies for treatment of diabetes and its complications. PMID:26816666

  1. Subjective Stress, Salivary Cortisol, and Electrophysiological Responses to Psychological Stress

    PubMed Central

    Qi, Mingming; Gao, Heming; Guan, Lili; Liu, Guangyuan; Yang, Juan

    2016-01-01

    The present study aimed to investigate the subjective stress, salivary cortisol, and electrophysiological responses to psychological stress induced by a modified version of a mental arithmetic task. Fifteen participants were asked to estimate whether the multiplication product of two-decimal numbers was above 10 or not either with a time limit (the stress condition) or without a time limit (the control condition). The results showed that participants reported higher levels of stress, anxiety, and negative affect in the stress condition than they did in the control condition. Moreover, the salivary cortisol level continued to increase after the stress condition but exhibited a sharp decrease after the control condition. In addition, the electrophysiological data showed that the amplitude of the frontal-central N1 component was larger for the stress condition than it was for the control condition, while the amplitude of the frontal-central P2 component was larger for the control condition than it was for the stress condition. Our study suggests that the psychological stress characteristics of time pressure and social-evaluative threat caused dissociable effects on perception and on the subsequent attentional resource allocation of visual information. PMID:26925026

  2. Apport des moyens endoscopiques dans la dilatation des sténoses caustiques de l’œsophage

    PubMed Central

    Seydou, Togo; Abdoulaye, Ouattara Moussa; xing, Li; Zi, Sanogo Zimogo; sekou, Koumaré; Wen, Yang Shang; Ibrahim, Sankare; Sekou, Toure Cheik Ahmed; Boubacar, Maiga Ibrahim; Saye, Jacque; Jerome, Dakouo Dodino; Dantoumé, Toure Ousmane; Sadio, Yena

    2016-01-01

    Introduction Toutes les sténoses symptomatiques de l’œsophage peuvent être dilatées par voie endoscopique. Nous évaluons l'apport des moyens endoscopiques dans la prise en charge de la dilatation œsophagienne pour sténose caustique de l’œsophage (SCO) au Mali. Méthodes IL s'agissait d'une étude descriptive et prospective réalisée dans le service de chirurgie thoracique à l'hôpital du Mali. Au total 46 dossiers cliniques de patients on été enregistrés et subdivisés en 4 groupes en fonction de la topographie des lésions cicatricielles. Le nombre de cas d'assistance endoscopique réalisé a été déterminé afin de comprendre l'apport des moyens endoscopiques dans le succès de la dilatation des SCO. Pour les 2 différentes méthodes de dilatation utilisées, le résultat du traitement et le coût ont comparés. Résultats La FOGD a été utilisée dans 19 cas (41.30%) de dilatation avec la bougie de Savary Guillard et dans 47.82% des cas dans la dilatation de Lerut. La vidéo-laryngoscopie a été utilisé 58.69% des cas de dilatation à la bougie de Lerut. Le passage de guide métallique et / ou de fil-guide a été réalisée dans 39.13% avec la vidéo laryngoscopie et dans 58.68% avec la FOGD. Dans la comparaison des deux méthodes, il existe une différence significative dans la survenue des complications (p=0.04075), l'anesthésie générale (p=0.02287), l'accessibilité à la méthode (p=0.04805) et la mortalité (p=0.00402). Conclusion La SCO est une pathologie grave et sous évaluée au Mali. Les moyens endoscopiques contribuent considérablement au succès de la dilatation œsophagienne pour sténose caustique dans les différentes méthodes utilisées. PMID:27200129

  3. [Parkinson's disease and nucleolar stress].

    PubMed

    Zhou, Qingqing; Chen, Yongping; Wei, Qianqian; Shang, Huifang

    2016-06-01

    Parkinson's disease (PD) is a common age-related neurodegenerative disorder characterized mainly by motor dysfunction resulting in bradykinesia, rigidity, tremor, gait impairment, and postural instability. The classic pathogenic feature of PD is preferential loss of dopaminergic neurons in the substantia nigra. Downregulation of rRNA transcription is one of major mechanisms to maintain cellular homeostasis under stress conditions. Nucleolar stress has emerged as a component of the degenerative process caused by impaired rRNA transcription and altered nucleolar integrity. Recent study has indicated that the response to stress conditions and quality control mechanisms are impaired in PD, and that metabolic stress may be a trigger mechanism for PD. This review aims to present evidence for a role of nucleolar stress in PD and has summarized mechanisms by which nucleolar stress may play a role in the progression of PD. PMID:27264829

  4. A Piezoelectric Shear Stress Sensor

    NASA Technical Reports Server (NTRS)

    Kim, Taeyang; Saini, Aditya; Kim, Jinwook; Gopalarathnam, Ashok; Zhu, Yong; Palmieri, Frank L.; Wohl, Christopher J.; Jiang, Xiaoning

    2016-01-01

    In this paper, a piezoelectric sensor with a floating element was developed for shear stress measurement. The piezoelectric sensor was designed to detect the pure shear stress suppressing effects of normal stress generated from the vortex lift-up by applying opposite poling vectors to the: piezoelectric elements. The sensor was first calibrated in the lab by applying shear forces and it showed high sensitivity to shear stress (=91.3 +/- 2.1 pC/Pa) due to the high piezoelectric coefficients of PMN-33%PT (d31=-1330 pC/N). The sensor also showed almost no sensitivity to normal stress (less than 1.2 pC/Pa) because of the electromechanical symmetry of the device. The usable frequency range of the sensor is 0-800 Hz. Keywords: Piezoelectric sensor, shear stress, floating element, electromechanical symmetry

  5. Stress, catecholaminergic system and cancer.

    PubMed

    Krizanova, O; Babula, P; Pacak, K

    2016-07-01

    Stress as a modern civilization factor significantly affects our lives. While acute stress might have a positive effect on the organism, chronic stress is usually detrimental and might lead to serious health complications. It is known that stress induced by the physical environment (temperature-induced cold stress) can significantly impair the efficacy of cytotoxic chemotherapies and the anti-tumor immune response. On the other hand, epidemiological evidence has shown that patients taking drugs known as β-adrenergic antagonists ("β-blockers"), which are commonly prescribed to treat arrhythmia, hypertension, and anxiety, have significantly lower rates of several cancers. In this review, we summarize the current knowledge about catecholamines as important stress hormones in tumorigenesis and discuss the use of β-blockers as the potential therapeutic agents. PMID:27398826

  6. A luminescent nanocrystal stress gauge

    SciTech Connect

    Choi, Charina; Koski, Kristie; Olson, Andrew; Alivisatos, Paul

    2010-10-25

    Microscale mechanical forces can determine important outcomes ranging from the site of material fracture to stem cell fate. However, local stresses in a vast majority of systems cannot be measured due to the limitations of current techniques. In this work, we present the design and implementation of the CdSe/CdS core/shell tetrapod nanocrystal, a local stress sensor with bright luminescence readout. We calibrate the tetrapod luminescence response to stress, and use the luminescence signal to report the spatial distribution of local stresses in single polyester fibers under uniaxial strain. The bright stress-dependent emission of the tetrapod, its nanoscale size, and its colloidal nature provide a unique tool that may be incorporated into a variety of micromechanical systems including materials and biological samples to quantify local stresses with high spatial resolution.

  7. Plant adaptation to drought stress

    PubMed Central

    Basu, Supratim; Ramegowda, Venkategowda; Kumar, Anuj; Pereira, Andy

    2016-01-01

    Plants in their natural habitats adapt to drought stress in the environment through a variety of mechanisms, ranging from transient responses to low soil moisture to major survival mechanisms of escape by early flowering in absence of seasonal rainfall. However, crop plants selected by humans to yield products such as grain, vegetable, or fruit in favorable environments with high inputs of water and fertilizer are expected to yield an economic product in response to inputs. Crop plants selected for their economic yield need to survive drought stress through mechanisms that maintain crop yield. Studies on model plants for their survival under stress do not, therefore, always translate to yield of crop plants under stress, and different aspects of drought stress response need to be emphasized. The crop plant model rice ( Oryza sativa) is used here as an example to highlight mechanisms and genes for adaptation of crop plants to drought stress. PMID:27441087

  8. Etude theorique et experimentale des evaporateurs de dioxyde de carbone operant dans des conditions de givrage

    NASA Astrophysics Data System (ADS)

    Bendaoud, Adlane Larbi

    Les evaporateurs de refrigeration sont surtout du type tube a ailettes, appeles serpentins, et fonctionnent dans l'une des conditions suivantes: seche, humide ou avec formation de givre. Il a ete demontre que la formation du givre sur la paroi exterieure de l'echangeur engendre une surconsommation energetique a cause des operations de degivrage puisque 15 a 20% seulement de la chaleur produite sert au degivrage tandis que le reste est dissipee dans l'environnement [1]. Avec l'avenement des nouveaux refrigerants, moins nocifs envers l'environnement, l'industrie du froid se trouve penalisee du fait que peu ou pas de composantes mecaniques (compresseur, pompe, echangeur...etc.) adaptees sont disponibles [3]. Il s'agit pour la communaute des frigoristes de combler ce retard technologique en redeveloppant ces composantes mecaniques afin qu'elles soient adaptees aux nouveaux refrigerants. Dans cette optique, et afin de mieux comprendre le comportement thermique des evaporateurs au CO2 fonctionnant dans des conditions seches, qu'un groupe de chercheurs du CanmetENERGIE avaient lance, en 2000, un programme de R & D. Dans le cadre de programme un outil de simulation des evaporateurs au CO2 a ete developpe et un banc d'essai contenant une boucle secondaire de refrigeration utilisant le CO2 comme refrigerant a ete construit. Comme continuite de ce travail de recherche, en 2006 ce meme groupe de recherche a lance un nouveau projet qui consiste a faire une etude theorique et experimentale des evaporateurs au CO2 operants dans des conditions de givrage. Et, c'est exactement dans le cadre de ce projet que se positionne ce travail de these. Ce travail de recherche a ete entrepris pour mieux comprendre le comportement thermique et hydrodynamique des serpentins fonctionnant dans des conditions de givrage, l'effet des circuits de refrigerant ainsi que celui des parametres geometriques et d'operation. Pour cela, un travail theorique supporte par une etude experimentale a ete effectue

  9. Rôle des hyrates dans la formation de Titan et des satellites réguliers

    NASA Astrophysics Data System (ADS)

    Mousis, O.

    2001-12-01

    Cette these est dediee a l'etude de l'origine de Titan et de son atmosphere. Dans l'hypothese ou la subnebuleuse de Saturne etait geometriquement mince, le modele de disque turbulent utilise, derive des travaux de Dubrulle (1993), est moins dense que le modele de Prinn et Fegley (1981). De ce fait, les conversions de Co en CH4 et de N2 en NH3 ont ete inhibees dans la subnebuleuse, contrairement a ce qui est couramment admis pour interpreter la presence du methane dans l'atmosphere de Titan. C'est pourquoi nous avons developpe un nouveau scenario de la formation de titan, qui tient compte simultanement des contraintes resultant de la chimie de la subnebuleuse et des abondances de CH4, N2 et CH3D mesurees dans l'atmosphere du satellite. Nous faisons l'hypothese que ces gaz proviennent initialement de la vaporisation du nuage presolaire, qui s'effondra et forma le Soleil et son disque environnant. Lors du refroidissement de la nebuleuse, les volatils auraient ete pieges sous formes de clathrates d'hydrates dans les grains, puis dans les planetesimaux qu'ils formerent. Les planetesimaux hydrates a l'origine de la formation de Titan seraient alors des rescapes de l'effondrement hydsrodynamique de la feeding zone de Saturne. Ce scenario a ete applique aux subnebuleuses de Jupiter et d'Uranus, et a apporte un certain nombre de contraintes sur la formation des satellites reguliers de ces planetes. Le temps et la zone de formation des grains cometaires ont egalement ete estimes dans la nebuleuse solaire. Enfin, l'etude experimentale de la temperature de fusion du dihydrate d'ammoniac dans la gamme des hautes pressions a apporte des nouvelles donnees thermodynamiques qui permettront d'ameliorer les modeles de l'interieur de Titan.

  10. Radiology of musculoskeletal stress injuries

    SciTech Connect

    Keats, T.E.

    1989-01-01

    With the new emphasis on physical fitness, musculoskeletal stress injuries are being seen with greater frequency in children and adults, and in locations that are not widely associated with stress injury. Some of the injuries continue to be mistaken for signs of more serious illnesses, such as infection and neoplasm, and this may lead to unnecessary investigative effort. This book covers both the classic stress injuries and the new manifestations.

  11. Left ventricular wall stress compendium.

    PubMed

    Zhong, L; Ghista, D N; Tan, R S

    2012-01-01

    Left ventricular (LV) wall stress has intrigued scientists and cardiologists since the time of Lame and Laplace in 1800s. The left ventricle is an intriguing organ structure, whose intrinsic design enables it to fill and contract. The development of wall stress is intriguing to cardiologists and biomedical engineers. The role of left ventricle wall stress in cardiac perfusion and pumping as well as in cardiac pathophysiology is a relatively unexplored phenomenon. But even for us to assess this role, we first need accurate determination of in vivo wall stress. However, at this point, 150 years after Lame estimated left ventricle wall stress using the elasticity theory, we are still in the exploratory stage of (i) developing left ventricle models that properly represent left ventricle anatomy and physiology and (ii) obtaining data on left ventricle dynamics. In this paper, we are responding to the need for a comprehensive survey of left ventricle wall stress models, their mechanics, stress computation and results. We have provided herein a compendium of major type of wall stress models: thin-wall models based on the Laplace law, thick-wall shell models, elasticity theory model, thick-wall large deformation models and finite element models. We have compared the mean stress values of these models as well as the variation of stress across the wall. All of the thin-wall and thick-wall shell models are based on idealised ellipsoidal and spherical geometries. However, the elasticity model's shape can vary through the cycle, to simulate the more ellipsoidal shape of the left ventricle in the systolic phase. The finite element models have more representative geometries, but are generally based on animal data, which limits their medical relevance. This paper can enable readers to obtain a comprehensive perspective of left ventricle wall stress models, of how to employ them to determine wall stresses, and be cognizant of the assumptions involved in the use of specific models

  12. Neuronal responses to physiological stress.

    PubMed

    Kagias, Konstantinos; Nehammer, Camilla; Pocock, Roger

    2012-01-01

    Physiological stress can be defined as any external or internal condition that challenges the homeostasis of a cell or an organism. It can be divided into three different aspects: environmental stress, intrinsic developmental stress, and aging. Throughout life all living organisms are challenged by changes in the environment. Fluctuations in oxygen levels, temperature, and redox state for example, trigger molecular events that enable an organism to adapt, survive, and reproduce. In addition to external stressors, organisms experience stress associated with morphogenesis and changes in inner chemistry during normal development. For example, conditions such as intrinsic hypoxia and oxidative stress, due to an increase in tissue mass, have to be confronted by developing embryos in order to complete their development. Finally, organisms face the challenge of stochastic accumulation of molecular damage during aging that results in decline and eventual death. Studies have shown that the nervous system plays a pivotal role in responding to stress. Neurons not only receive and process information from the environment but also actively respond to various stresses to promote survival. These responses include changes in the expression of molecules such as transcription factors and microRNAs that regulate stress resistance and adaptation. Moreover, both intrinsic and extrinsic stresses have a tremendous impact on neuronal development and maintenance with implications in many diseases. Here, we review the responses of neurons to various physiological stressors at the molecular and cellular level. PMID:23112806

  13. Neuronal Responses to Physiological Stress

    PubMed Central

    Kagias, Konstantinos; Nehammer, Camilla; Pocock, Roger

    2012-01-01

    Physiological stress can be defined as any external or internal condition that challenges the homeostasis of a cell or an organism. It can be divided into three different aspects: environmental stress, intrinsic developmental stress, and aging. Throughout life all living organisms are challenged by changes in the environment. Fluctuations in oxygen levels, temperature, and redox state for example, trigger molecular events that enable an organism to adapt, survive, and reproduce. In addition to external stressors, organisms experience stress associated with morphogenesis and changes in inner chemistry during normal development. For example, conditions such as intrinsic hypoxia and oxidative stress, due to an increase in tissue mass, have to be confronted by developing embryos in order to complete their development. Finally, organisms face the challenge of stochastic accumulation of molecular damage during aging that results in decline and eventual death. Studies have shown that the nervous system plays a pivotal role in responding to stress. Neurons not only receive and process information from the environment but also actively respond to various stresses to promote survival. These responses include changes in the expression of molecules such as transcription factors and microRNAs that regulate stress resistance and adaptation. Moreover, both intrinsic and extrinsic stresses have a tremendous impact on neuronal development and maintenance with implications in many diseases. Here, we review the responses of neurons to various physiological stressors at the molecular and cellular level. PMID:23112806

  14. Does stress induce bowel dysfunction?

    PubMed

    Chang, Yu-Ming; El-Zaatari, Mohamad; Kao, John Y

    2014-08-01

    Psychological stress is known to induce somatic symptoms. Classically, many gut physiological responses to stress are mediated by the hypothalamus-pituitary-adrenal axis. There is, however, a growing body of evidence of stress-induced corticotrophin-releasing factor (CRF) release causing bowel dysfunction through multiple pathways, either through the HPA axis, the autonomic nervous systems, or directly on the bowel itself. In addition, recent findings of CRF influencing the composition of gut microbiota lend support for the use of probiotics, antibiotics, and other microbiota-altering agents as potential therapeutic measures in stress-induced bowel dysfunction. PMID:24881644

  15. Designing a Stress Management Curiculum.

    ERIC Educational Resources Information Center

    Crawford, Michael E.

    1982-01-01

    Educators must develop, for therapeutic recreation students, curriculum that teaches stress management techniques and theories. Guidelines for curriculum revision or enhancement in this area are presented. (CJ)

  16. Stressing Zebrafish for Behavioral Genetics

    PubMed Central

    Clark, Karl J.; Boczek, Nicole J.; Ekker, Stephen C.

    2012-01-01

    Synopsis The stress response is a normal reaction to a real or perceived threat. However, stress response systems that are overwhelmed or out of balance can increase both the incidence and severity of diseases including addiction and mood and anxiety disorders. Using an animal model with both genetic diversity and large family size can help discover the specific genetic and environmental contributions to these behavioral diseases. The stress response has been studied extensively in teleosts because of their importance in food production. The zebrafish (Danio rerio) is a major model organism with a strong record for use in developmental biology, genetic screening, and genomic studies. More recently, the stress response of larval and adult zebrafish has been documented. High-throughput automated tracking systems make possible behavioral readouts of the stress response in zebrafish. This non-invasive measure of the stress response can be combined with mutagenesis methods to dissect the genes involved in complex stress response behaviors in vertebrates. Understanding the genetic and epigenetic basis for the stress response in vertebrates will help to develop advanced screening and therapies for stress-aggravated diseases like addiction and mood and anxiety disorders. PMID:21615261

  17. Conductivite dans le modele de Hubbard bi-dimensionnel a faible couplage

    NASA Astrophysics Data System (ADS)

    Bergeron, Dominic

    Le modele de Hubbard bi-dimensionnel (2D) est souvent considere comme le modele minimal pour les supraconducteurs a haute temperature critique a base d'oxyde de cuivre (SCHT). Sur un reseau carre, ce modele possede les phases qui sont communes a tous les SCHT, la phase antiferromagnetique, la phase supraconductrice et la phase dite du pseudogap. Il n'a pas de solution exacte, toutefois, plusieurs methodes approximatives permettent d'etudier ses proprietes de facon numerique. Les proprietes optiques et de transport sont bien connues dans les SCHT et sont donc de bonne candidates pour valider un modele theorique et aider a comprendre mieux la physique de ces materiaux. La presente these porte sur le calcul de ces proprietes pour le modele de Hubbard 2D a couplage faible ou intermediaire. La methode de calcul utilisee est l'approche auto-coherente a deux particules (ACDP), qui est non-perturbative et inclue l'effet des fluctuations de spin et de charge a toutes les longueurs d'onde. La derivation complete de l'expression de la conductivite dans l'approche ACDP est presentee. Cette expression contient ce qu'on appelle les corrections de vertex, qui tiennent compte des correlations entre quasi-particules. Pour rendre possible le calcul numerique de ces corrections, des algorithmes utilisant, entre autres, des transformees de Fourier rapides et des splines cubiques sont developpes. Les calculs sont faits pour le reseau carre avec sauts aux plus proches voisins autour du point critique antiferromagnetique. Aux dopages plus faibles que le point critique, la conductivite optique presente une bosse dans l'infrarouge moyen a basse temperature, tel qu'observe dans plusieurs SCHT. Dans la resistivite en fonction de la temperature, on trouve un comportement isolant dans le pseudogap lorsque les corrections de vertex sont negligees et metallique lorsqu'elles sont prises en compte. Pres du point critique, la resistivite est lineaire en T a basse temperature et devient

  18. Geochemistry of dissolved trace elements and heavy metals in the Dan River Drainage (China): distribution, sources, and water quality assessment.

    PubMed

    Meng, Qingpeng; Zhang, Jing; Zhang, Zhaoyu; Wu, Tairan

    2016-04-01

    Dissolved trace elements and heavy metals in the Dan River drainage basin, which is the drinking water source area of South-to-North Water Transfer Project (China), affect large numbers of people and should therefore be carefully monitored. To investigate the distribution, sources, and quality of river water, this study integrating catchment geology and multivariate statistical techniques was carried out in the Dan River drainage from 99 river water samples collected in 2013. The distribution of trace metal concentrations in the Dan River drainage was similar to that in the Danjiangkou Reservoir, indicating that the reservoir was significantly affected by the Dan River drainage. Moreover, our results suggested that As, Sb, Cd, Mn, and Ni were the major pollutants. We revealed extremely high concentrations of As and Sb in the Laoguan River, Cd in the Qingyou River, Mn, Ni, and Cd in the Yinhua River, As and Sb in the Laojun River, and Sb in the Dan River. According to the water quality index, water in the Dan River drainage was suitable for drinking; however, an exposure risk assessment model suggests that As and Sb in the Laojun and Laoguan rivers could pose a high risk to humans in terms of adverse health and potential non-carcinogenic effects. PMID:26782327

  19. [Posttraumatic stress disorder (PTSD)].

    PubMed

    Martényi, Ferenc

    2004-11-14

    The diagnosis of posttraumatic stress disorder (PTSD) has been introduced in 1980. The diagnosis, as construct raises several political, moral, legal, and compensation issues. PTSD is considered as a multisystemic dysregulation, involving the hypothalamic- pituitary - adrenal axis, adrenergic hypersensibility, and serotonergic dysfunction. The prevalence of PTSD is 1-9% in the general population, but substantially higher among victims of traumatic events: 19-70%. Placebo controlled studies provide a body of evidence concerning efficacy of selective serotonin reuptake inhibitors in the treatment of PTSD both in the acute and maintenance treatments. Studies with balanced male-female ratio suggest no gender-related differences in the clinical response, furthermore both civilians and veterans improved significantly for selective serotonin reuptake inhibitor treatment. PMID:16106902

  20. Post traumatic stress disorder.

    PubMed

    Tiller, J; Kyrios, M; Bennett, P

    1996-10-01

    Post traumatic stress disorder (PTSD) occurs after a person has been exposed to a traumatic event involving actual or threatened death, and has responded with intense fear or helplessness. The event is then persistently re-experienced. The person avoids stimuli associated with the trauma and experiences a numbing of general responsiveness. Symptoms of increased arousal can occur as well as depression and anxiety. PTSD causes clinically significant distress or impairment in social, occupational, or other important areas of functioning. The general practitioner is uniquely placed to identify PTSD and can have a key role in treatment. Cognitive behavioural treatment is a central therapeutic approach and can be carried out in general practice. The issues are to counteract the physiological components, expose the patient to the feared situation and help the patient to relearn that the stimuli are not necessarily associated with danger or threat. Repeated brief consultations over time can facilitate this process. PMID:8936738

  1. HTTF Core Stress Analysis

    SciTech Connect

    Brian D. Hawkes; Richard Schultz

    2012-07-01

    In accordance with the need to determine whether cracking of the ceramic core disks which will be constructed and used in the High Temperature Test Facility (HTTF) for heatup and cooldown experiments, a set of calculation were performed using Abaqus to investigate the thermal stresses levels and likelihood for cracking. The calculations showed that using the material properties provided for the Greencast 94F ceramic, cracking is predicted to occur. However, this modeling does not predict the size or length of the actual cracks. It is quite likely that cracks will be narrow with rough walls which would impede the flow of coolant gases entering the cracks. Based on data recorded at Oregon State University using Greencast 94F samples that were heated and cooled at prescribed rates, it was concluded that the likelihood that the cracks would be detrimental to the experimental objectives is small.

  2. Measuring Science Teachers' Stress Level Triggered by Multiple Stressful Conditions

    ERIC Educational Resources Information Center

    Halim, Lilia; Samsudin, Mohd Ali; Meerah, T. Subahan M.; Osman, Kamisah

    2006-01-01

    The complexity of science teaching requires science teachers to encounter a range of tasks. Some tasks are perceived as stressful while others are not. This study aims to investigate the extent to which different teaching situations lead to different stress levels. It also aims to identify the easiest and most difficult conditions to be regarded…

  3. Stress Matters: Effects of Anticipated Lexical Stress on Silent Reading

    ERIC Educational Resources Information Center

    Breen, Mara; Clifton, Charles, Jr.

    2011-01-01

    This paper presents findings from two eye-tracking studies designed to investigate the role of metrical prosody in silent reading. In Experiment 1, participants read stress-alternating noun-verb or noun-adjective homographs (e.g. "PREsent", "preSENT") embedded in limericks, such that the lexical stress of the homograph, as determined by context,…

  4. Stress and Stress Management Strategies Among Botswana Women Lecturers.

    ERIC Educational Resources Information Center

    Loate, Irene M.; Marais, James L.

    1996-01-01

    A stress inventory administered to black women faculty at seven Botswana colleges and universities (n=201) found the greatest stressor to be student class boycotts, followed by uncertainties about their institution's future and dual roles. Almost two-thirds experienced fatigue. The most successful stress management technique was positive thinking.…

  5. Stressing Out: Connecting Race, Gender, and Stress with Faculty Productivity

    ERIC Educational Resources Information Center

    Eagan, M. Kevin, Jr.; Garvey, Jason C.

    2015-01-01

    This study uses multilevel modeling to analyze data from a national sample of full-time, undergraduate faculty at four-year institutions to examine the connections among race, gender, sources of stress, and productivity in the areas of research, teaching, and service. We find that stress due to discrimination has particular negative salience for…

  6. Stress and Stress Relief in the Educational Research Classroom.

    ERIC Educational Resources Information Center

    Wilson, Vicki A.

    Factors that increase stress and those that decrease stress were studied with 33 graduate students in an introductory educational research course. Participants completed the Statistical Anxiety Rating Scale (STARS) (R. Cruse, R. Cash, and D. Bolton, 1985) and were asked to rate their anxiety daily during the 4 weeks of the class. The instructor's…

  7. Adolescent Stress: The Relationship between Stress and Mental Health Problems

    ERIC Educational Resources Information Center

    Grant, Kathryn E.; Behling, Steven; Gipson, Polly Y.; Ford, Rebecca E.

    2005-01-01

    Although low levels of stressful life experiences are considered to be a normal part of development, higher levels can constitute a threat to the well-being and healthy development of children and adolescents. Adolescents are exposed to increased rates of stressful life experiences and there is some evidence that increases in stressors account, at…

  8. [Pharmacotherapy of stress incontinence].

    PubMed

    Jost, W H; Marsalek, P; Michel, M C

    2005-10-14

    Female urinary incontinence is a medical and social problem with a large prevalence. Stress urinary incontinence (SUI) is the most common form of urinary incontinence and is responsible for 49 % of all incontinence, if mixed forms are included even for 78 %. As of yet, apart from "off-label" treatment, there is no pharmacological treatment available for stress urinary incontinence. For instance, estrogens are used in menopausal patients but a substantial effect in the treatment of SUI has not been demonstrated. a-Adrenergics, such as phenylpropanolamine and midodrine, and b-adrenergics, such as clenbuterol, are also used in "off-label" therapy. A recently conducted meta-analysis of 15 randomised studies with female patients who received a- und b-adrenergics as part of their therapy, failed to detect efficacy compared to placebo. Tricyclic antidepressives, such as imipramine and doxepine, which are used for the treatment of urge incontinence, are also used "off-label" in the treatment of SUI. However, no placebo-controlled studies have been conducted so far. The serotonin-norepinephrine reuptake inhibitor duloxetine represents a new therapeutic approach in the treatment of SUI. It has shown positive effects on bladder and urethra in animal experiments, most likely through an effect on the Onuf's nucleus in the spinal cord. In randomised, placebo-controlled studies (phase II and III) in women with SUI, a significant and clinically relevant reduction in urinary incontinence episodes as well as an improvement in the quality of life compared to placebo was shown. PMID:16231235

  9. Stress evolution in solidifying coatings

    NASA Astrophysics Data System (ADS)

    Payne, Jason Alan

    The goal of this study is to measure, in situ, and control the evolution of stress in liquid applied coatings. In past studies, the stress in a coating was determined after processing (i.e., drying or curing). However, by observing a coating during drying or curing, the effects of processing variables (e.g., temperature, relative humidity, composition, etc.) on the stress state can be better determined. To meet the project goal, two controlled environment stress measurement devices, based on a cantilever deflection measurement principle, were constructed. Stress evolution experiments were completed for a number of coating systems including: solvent-cast homopolymers, tape-cast ceramics, aqueous gelatins, and radiation-cured multifunctional acrylates. In the majority of systems studied here, the final stresses were independent of coating thickness and solution concentration. Typical stress magnitudes for solvent-cast polymers ranged from zero to 18 MPa depending upon the pure polymer glass transition temperature (Tsb{g}), the solvent volatility, and additional coating components, such as plasticizers. Similar magnitudes and dependencies were observed in tape-cast ceramic layers. Stresses in gelatin coatings reached 50 MPa (due to the high Tsb{g} of the gelatin) and were highly dependent upon drying temperature and relative humidity. In contrast to the aforementioned coatings, stress in UV-cured tri- and tetrafunctional acrylate systems showed a large thickness dependence. For these materials, stress evolution rate and magnitude increased with photoinitiator concentration and with light intensity. Somewhat unexpectedly, larger monomer functionality led to greater stresses at faster rates even though the overall conversion fell. The stress magnitude and evolution rate at any stage in the solidification process are the result of a competition between shrinkage (due to drying, curing, etc.) and stress relaxation. A firm understanding of the mechanical, the thermal, and

  10. Global Stress Variation over Time

    NASA Astrophysics Data System (ADS)

    Yi, H.; Lu, Z.; Wen, L.

    2015-12-01

    Understanding how stress changes over time is important as it is related to studies of earthquake triggering and mantle rheology. We calculate stress variation at the Earth's surface on the global scale from 2003 to 2014, resultant from several major physical forces acting on the Earth. The physical forces we considered include the surface loading due to terrestrial water storage (TWS), force associated with post-glacial rebound (PGR) and tidal loading (including solid tide and ocean tide). The stress change associated with TWS is calculated in this way: we infer TWS from monthly gravity field of the Gravity Recovery and Climate Experiment (GRACE), in which gravity variation associated with PGR has been removed; we then estimate stress change at the Earth's surface as the elastic response of the GRACE-inferred TWS change. The stress change associated with PGR is calculated as the rate of viscoelastic stress change responding to ice loading from ICE-5G model. And, tidal stress is calculated as the elastic response of the Earth to the traction forces of the Sun and the Moon (solid tide) and to the loading of ocean tide. The total stress change is the sum of the stress changes associated with these three types of forces. As first result, in the study period from 2003 to 2014, the radial normal stress variation exhibits a prominent decreasing trend in southern Africa and Queen Maud Land of Antarctica, an increasing trend in Alaska of the US (United States), Greenland and Marie Byrd Land of Antarctica, and strong annual cycles in southern Africa and Alaska of the US. We will present the geographical distribution of global stress variation from 2003 to 2014 and discuss its possible implications.

  11. Oxidative stress by inorganic nanoparticles.

    PubMed

    Tee, Jie Kai; Ong, Choon Nam; Bay, Boon Huat; Ho, Han Kiat; Leong, David Tai

    2016-05-01

    Metallic and metallic oxide nanoparticles (NPs) have been increasingly used for various bio-applications owing to their unique physiochemical properties in terms of conductivity, optical sensitivity, and reactivity. With the extensive usage of NPs, increased human exposure may cause oxidative stress and lead to undesirable health consequences. To date, various endogenous and exogenous sources of oxidants contributing to oxidative stress have been widely reported. Oxidative stress is generally defined as an imbalance between the production of oxidants and the activity of antioxidants, but it is often misrepresented as a single type of cellular stress. At the biological level, NPs can initiate oxidative stress directly or indirectly through various mechanisms, leading to profound effects ranging from the molecular to the disease level. Such effects of oxidative stress have been implicated owing to their small size and high biopersistence. On the other hand, cellular antioxidants help to counteract oxidative stress and protect the cells from further damage. While oxidative stress is commonly known to exert negative biological effects, measured and intentional use of NPs to induce oxidative stress may provide desirable effects to either stimulate cell growth or promote cell death. Hence, NP-induced oxidative stress can be viewed from a wide paradigm. Because oxidative stress is comprised of a wide array of factors, it is also important to use appropriate assays and methods to detect different pro-oxidant and antioxidant species at molecular and disease levels. WIREs Nanomed Nanobiotechnol 2016, 8:414-438. doi: 10.1002/wnan.1374 For further resources related to this article, please visit the WIREs website. PMID:26359790

  12. Occupational Stress and Perceived Organizational Effectiveness in Formal Groups: An Examination of Stress Level and Stress Type.

    ERIC Educational Resources Information Center

    Allen, R. Douglas; And Others

    1982-01-01

    Studied the relationship between stress and the perceived effectiveness of formal organization groups. Analysis of data from four firms showed a negative relationship. Results suggest that the type of stress moderates the stress and effectiveness relationship. Dysfunctional stress was the dominant type of stress in all four firms. (Author)

  13. Comparative Studies of Acculturative Stress.

    ERIC Educational Resources Information Center

    Berry, J. W.; And Others

    1987-01-01

    Studies of acculturative stress are reported from Canada. The reduction in health status among people undergoing acculturation has psychological, somatic, and social aspects. The stress varies across types of groups and individual differences. Further study is needed to determine variations across host societies. (VM)

  14. Teacher Stress: Selected ERIC Resources.

    ERIC Educational Resources Information Center

    Schwanke, Dean, Comp.

    This annotated bibliography lists journal articles and research reports on the problem of teacher stress and burnout. The first two sections include citations of general discussions which clarify the distinction between desirable and undesirable stress. The third section lists research and survey reports on teacher morale and job satisfaction. The…

  15. Stress, Wet Litter, and Colibacillosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stress can lead to either an increase or decrease in disease susceptibility. The effects are so variable because they are specific for the type, degree, and duration of stress, are influenced by the complexity of the immune system and the neuroendocrine system, and are strongly influenced by individ...

  16. Casing and tubing connection stresses

    SciTech Connect

    Schneider, W.P.

    1982-08-01

    By use of a simple theoretical analysis, the transverse stresses in couplings and pipe ends of API eight-round and buttress threaded connections caused by makeup and pressures have been calculated and tabulated. Stresses for 680 specified combinations of casing and tubing size, grade, and thread type are examined.

  17. Moral Stress in Teaching Practice

    ERIC Educational Resources Information Center

    Colnerud, Gunnel

    2015-01-01

    The purpose of this article is to study whether moral stress is a phenomenon relevant to teaching practice and which may make a significant contribution to understanding why teachers repeatedly reported feeling burdened by work. Moral stress can be caused by acting in conflict with one's own conscience, e.g. when one knows the right thing to…

  18. School Psychologists, Stress, and Burnout.

    ERIC Educational Resources Information Center

    Miles, Dorothy D.; Chittooran, Mary M.

    School psychologists are often subject to severe stress when they work with troubled families and children. Burnout from physical, mental, or emotional exhaustion as a result of the chronic stress is not uncommon in the profession. One problem of being attentive to the needs of others is that the caregiver's needs often get overlooked or…

  19. BIological Psychology, Exercise, and Stress.

    ERIC Educational Resources Information Center

    Dishman, Rod K.

    1994-01-01

    Reviews theory and methods used by the field of biological psychology to study stress that have potential for understanding how behavioral and biological adaptations to the stress of exercise are integrated. The overview focuses on anxiety, depression, and physiological responsiveness to nonexercise stressors from the perspective of biological…

  20. Too Young to Be Stressed

    ERIC Educational Resources Information Center

    Bagdi, Aparna

    2004-01-01

    Over the past few years, the Times of India has published many articles and editorials on the topic of childhood stress. According to Ramanathan (2002), a recent study conducted by the All India Institute of Medical Sciences reveals that nearly 35 percent of children ages 8-14, especially in urban areas, are stressed enough to need clinical…

  1. Stress-relieved solder joints

    NASA Technical Reports Server (NTRS)

    Zemenick, C. J.

    1980-01-01

    Mechanical stress on solder joints is reduced by procedure for soldering electronic components to circuit boards. Procedure was developed for radio-frequency (RF) strip-line circuits, for which dimensions must be carefully controlled to minimize parasitic capacitance and inductance. Procedure consists of loosening component from its mounting after each lead is soldered relieving induced stresses before next soldering step.

  2. Rural Stress: Myths and Realities.

    ERIC Educational Resources Information Center

    Hansen, Thomas D.; McIntire, Walter G.

    A comparison between the common myths of "rural existence" and the documented realities of rural living explodes the myth that rural living is generally stress free, shows that life stress in rural settings can have deleterious effects on the function of individual and family, and provides a basis for exploring some implications of rural stress…

  3. Strategies for Alleviating Teacher Stress.

    ERIC Educational Resources Information Center

    Luckner, John L.

    1990-01-01

    This article provides background information on stress and presents five strategies intended to help teachers of hearing-impaired students manage their stress levels. Strategies include increasing self-awareness, reducing isolation, restoring perspective and balance, redefining problem situations, and developing and implementing an action plan.…

  4. Alleviating Stress for Women Administrators.

    ERIC Educational Resources Information Center

    Ten Elshof, Annette; Tomlinson, Elaine

    1981-01-01

    Describes a workshop designed to help women administrators assess individual stress levels. Stress can be alleviated through exercise, support groups or networking, sleep and diet, relaxation, guided fantasy, and planned activity. The long-term implications include preventing illness and making women more effective within the administrative…

  5. Stress Management. Program Evaluation Handbook.

    ERIC Educational Resources Information Center

    IOX Assessment Associates, Culver City, CA.

    Intended as a resource for individuals wishing to evaluate stress management programs, this handbook, one of a series of seven, provides a collection of measuring devices that can improve the quality of such evaluations. Chapter 1 introduces the handbook's contents and outlines evaluation related issues specific to stress management programs.…

  6. Thinking Styles and Job Stress.

    ERIC Educational Resources Information Center

    Quick, James C.; And Others

    1986-01-01

    Discusses the problem of stress in the workplace. Presents the theory that persons whose thinking styles are not in sync with their work responsibilities may suffer from greater stress than their peers. Recommends (1) person-job fitting, (2) early symptom screening, (3) job redesign programs, and (4) training and development. (CH)

  7. Water Stress and Protein Synthesis

    PubMed Central

    Dhindsa, R. S.; Cleland, R. E.

    1975-01-01

    Water stress causes a reduction in hydrostatic pressure and can cause an increase in abscisic acid in plant tissues. To assess the possible role of abscisic acid and hydrostatic pressure in water stress effects, we have compared the effects of water stress, abscisic acid, and an imposed hydrostatic pressure on the rate and pattern of protein synthesis in Avena coleoptiles. Water stress reduces the rate and changes the pattern of protein synthesis as judged by a double labeling ratio technique, Abscisic acid reduces the rate but does not alter the pattern of protein synthesis. Gibberellic acid reverses the abscisic acid-induced but not the stress-induced inhibition of protein synthesis. The effect of hydrostatic pressure depends on the gas used. With a 19: 1 N2-air mixture, the rate of protein synthesis is increased in stressed but not in turgid tissues. An imposed hydrostatic pressure alters the pattern of synthesis in stressed tissues, but does not restore the pattern to that found in turgid tissues. Because of the differences in response, we conclude that water stress does not affect protein synthesis via abscisic acid or reduced hydrostatic pressure. PMID:16659167

  8. Stress Correlates and Academic Achievement.

    ERIC Educational Resources Information Center

    Bentley, Donna Anderson; And Others

    An ongoing concern for educators is the identification of factors that contribute to or are associated with academic achievement; one such group of variables that has received little attention are those involving stress. The relationship between perceived sources of stress and academic achievement was examined to determine if reactions to stress…

  9. Life Stress and Academic Burnout

    ERIC Educational Resources Information Center

    Lin, Shu-Hui; Huang, Yun-Chen

    2014-01-01

    Stress has been shown to negatively affect learning. Academic burnout is a significant problem associated with poor academic performance. Although there has been increased attention on these two issues, literature on the relationship between students' life stress and burnout is relatively limited. This study surveys academic burnout and life…

  10. A Model of Teacher Stress

    ERIC Educational Resources Information Center

    Kyriacou, Chris; Sutcliffe, John

    1978-01-01

    A definition and model of teacher stress is presented which conceptualizes teacher stress as a response syndrome (anger or depression) mediated by (1) an appraisal of threat to the teacher's self-esteem or well-being and (2) coping mechanisms activated to reduce the perceived threat. (Author)

  11. Thermal stress and human performance.

    PubMed

    Enander, A E; Hygge, S

    1990-01-01

    There is evidence that the thermal stress encountered in many work environments may negatively affect various aspects of human performance and behavior. Evaluation of the empirical research is, however, complicated by differences in both the methodology and the definition of the basic stimulus. Effects of heat and cold stress are briefly reviewed, with particular regard to theoretical considerations. PMID:2189219

  12. Perceived stress in dental practice.

    PubMed

    Pop-Jordanova, Nada; Radojkova-Nikolovska, Vera; Markovska-Simoska, Silvana

    2013-01-01

    Stress is a normal physiological response to events that make us feel threatened, or upset our balance in some way. In medicine, it is known that stress, as an emotional state, can be a trigger for many psychosomatic disorders. Work stress and burnout are considered to be serious professional risks in dentistry. The dentist should be aware of these stressors and attempt to manage them in order to avoid becoming occupationally dissatisfied. On the other hand, the other common characteristic of modern life is a growing burden of different chronic diseases. Periodontal disease is one of the two most important oral diseases contributing to the global burden of chronic disease. The aim of this study was to assess the perceived stress in patients with periodontal pathologies, and to compare it with the stress in doctors-dentists and students of dentistry as future professionals. Our study confirmed the presence of significant stress in all three groups of examinees (patients, doctors, and students). Surprisingly, the obtained PSQ scores are similar in the examined groups. In addition, no differences between perceived stress in males and females have been found. There is a minimal positive correlation between age and obtained scores. However, stress must be evaluated as a risk factor both for professionals or for chronic dental patients and some response measures must be undertaken. PMID:24280887

  13. Prerelease Stress in Prison Inmates.

    ERIC Educational Resources Information Center

    Mabli, Jerome; And Others

    1985-01-01

    Examines prerelease stress in male and female inmates (N=98) at a minimum-security federal correctional institution through behavioral measures, Minnesota Multiphasic Personality Inventory scores, and Mood States Questionnaire. Results suggest that prerelease stress exists for some inmates; additional research is needed to determine other…

  14. Heat stress in feedlot cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Heat stress in feedlot cattle is a common summer time occurrence in cattle-producing parts of the world (United States, Australia, Brazil, etc.). The impact of heat stress on feedlot animals is quite varied--from little to no effect in a brief exposure, to causing reductions in feed intake, growth,...

  15. Testing the stress shadow hypothesis

    NASA Astrophysics Data System (ADS)

    Felzer, Karen R.; Brodsky, Emily E.

    2005-05-01

    A fundamental question in earthquake physics is whether aftershocks are predominantly triggered by static stress changes (permanent stress changes associated with fault displacement) or dynamic stresses (temporary stress changes associated with earthquake shaking). Both classes of models provide plausible explanations for earthquake triggering of aftershocks, but only the static stress model predicts stress shadows, or regions in which activity is decreased by a nearby earthquake. To test for whether a main shock has produced a stress shadow, we calculate time ratios, defined as the ratio of the time between the main shock and the first earthquake to follow it and the time between the last earthquake to precede the main shock and the first earthquake to follow it. A single value of the time ratio is calculated for each 10 × 10 km bin within 1.5 fault lengths of the main shock epicenter. Large values of the time ratio indicate a long wait for the first earthquake to follow the main shock and thus a potential stress shadow, whereas small values indicate the presence of aftershocks. Simulations indicate that the time ratio test should have sufficient sensitivity to detect stress shadows if they are produced in accordance with the rate and state friction model. We evaluate the 1989 MW 7.0 Loma Prieta, 1992 MW 7.3 Landers, 1994 MW 6.7 Northridge, and 1999 MW 7.1 Hector Mine main shocks. For each main shock, there is a pronounced concentration of small time ratios, indicating the presence of aftershocks, but the number of large time ratios is less than at other times in the catalog. This suggests that stress shadows are not present. By comparing our results to simulations we estimate that we can be at least 98% confident that the Loma Prieta and Landers main shocks did not produce stress shadows and 91% and 84% confident that stress shadows were not generated by the Hector Mine and Northridge main shocks, respectively. We also investigate the long hypothesized existence

  16. Fiber networks amplify active stress.

    PubMed

    Ronceray, Pierre; Broedersz, Chase P; Lenz, Martin

    2016-03-15

    Large-scale force generation is essential for biological functions such as cell motility, embryonic development, and muscle contraction. In these processes, forces generated at the molecular level by motor proteins are transmitted by disordered fiber networks, resulting in large-scale active stresses. Although these fiber networks are well characterized macroscopically, this stress generation by microscopic active units is not well understood. Here we theoretically study force transmission in these networks. We find that collective fiber buckling in the vicinity of a local active unit results in a rectification of stress towards strongly amplified isotropic contraction. This stress amplification is reinforced by the networks' disordered nature, but saturates for high densities of active units. Our predictions are quantitatively consistent with experiments on reconstituted tissues and actomyosin networks and shed light on the role of the network microstructure in shaping active stresses in cells and tissue. PMID:26921325

  17. BRCA1 and Oxidative Stress

    PubMed Central

    Yi, Yong Weon; Kang, Hyo Jin; Bae, Insoo

    2014-01-01

    The breast cancer susceptibility gene 1 (BRCA1) has been well established as a tumor suppressor and functions primarily by maintaining genome integrity. Genome stability is compromised when cells are exposed to oxidative stress. Increasing evidence suggests that BRCA1 regulates oxidative stress and this may be another mechanism in preventing carcinogenesis in normal cells. Oxidative stress caused by reactive oxygen species (ROS) is implicated in carcinogenesis and is used strategically to treat human cancer. Thus, it is essential to understand the function of BRCA1 in oxidative stress regulation. In this review, we briefly summarize BRCA1’s many binding partners and mechanisms, and discuss data supporting the function of BRCA1 in oxidative stress regulation. Finally, we consider its significance in prevention and/or treatment of BRCA1-related cancers. PMID:24704793

  18. Tectonic stress in the plates

    NASA Technical Reports Server (NTRS)

    Richardson, R. M.; Solomon, S. C.; Sleep, N. H.

    1979-01-01

    In the present paper, the basic set of global intraplate stress orientation data is plotted and tabulated. Although the global intraplate stress field is complicated, several large-scale patterns can be seen. Much of stable North America is characterized by an E-W to NE-SW trend for the maximum compressive stress. South American lithosphere beneath the Andes, and perhaps farther east in the stable interior, has horizontal compressive stresses trending E-W to NW-SE. Western Europe north of the Alps is characterized by a NW-SE trending maximum horizontal compression, while Asia has the maximum horizontal compressive stress trending more nearly N-S, especially near the Himalayan front.

  19. The stresses in stiffener openings

    NASA Technical Reports Server (NTRS)

    Marguerre, K

    1942-01-01

    The present study treats as a typical example a ring the center line of which is produced by the intersection of two circular cylinders of different diameter. Three load cases are analyzed: (1) Axial and circumferential stresses in both cylinders, the cylinder stresses themselves to be in the ratio conformal to the cylinders loaded under internal pressure. (2) Pure longitudinal tension in the large cylinder. (3) Pure shear (torsion) in the large cylinder. To simplify the calculation, it is assumed that the ring, compared to the shell, is very strong, so that its deformations have no perceptible effect on the stress condition in the shell. This provides an upper limit for the ring stresses actually produced in a shell design, for, according to the theory of stressed skin statics the shells, by elastic flexibility of the ring, regroup the forces deposited on it in such a manner that the ring is relieved.

  20. The Surgically Induced Stress Response

    PubMed Central

    Finnerty, Celeste C.; Mabvuure, Nigel Tapiwa; Ali, Arham; Kozar, Rosemary A.; Herndon, David N.

    2013-01-01

    The stress response to surgery, critical illness, trauma, and burns encompasses derangements of metabolic and physiological processes which induce perturbations in the inflammatory, acute phase, hormonal, and genomic responses. Hypermetabolism and hypercatabolism result, leading to muscle wasting, impaired immune function and wound healing, organ failure, and death. The surgery-induced stress response is largely similar to that triggered by traumatic injuries; the duration of the stress response, however, varies according to the severity of injury (surgical or traumatic). This spectrum of injuries and insults ranges from small lacerations to severe insults such as large poly-traumatic and burn injuries. Although the stress response to acute trauma evolved to improve chances of survival following injury, in modern surgical practice the stress response can be detrimental. PMID:24009246

  1. [Stress and the kynurenine pathway].

    PubMed

    Majláth, Zsófia; Vécsei, László

    2015-08-30

    The kynurenine pathway is the main route of tryptophan degradation which gives rise to several neuroactive metabolites. Kynurenic acid is an endogenous antagonist of excitatory receptors, which proved to be neuroprotective in the preclinical settings. Kynurenines have been implicated in the neuroendocrine regulatory processes. Stress induces several alterations in the kynurenine metabolism and this process may contribute to the development of stress-related pathological processes. Irritable bowel disease and gastric ulcer are well-known disorders which are related to psychiatric comorbidity and stress. In experimental conditions kynurenic acid proved to be beneficial by reducing inflammatory processes and normalizing microcirculation in the bowel. Further investigations are needed to better understand the relations of stress and the kynurenines, with the aim of developing novel therapeutic tools for stress-related pathologies. PMID:26299831

  2. A piezoelectric shear stress sensor

    NASA Astrophysics Data System (ADS)

    Kim, Taeyang; Saini, Aditya; Kim, Jinwook; Gopalarathnam, Ashok; Zhu, Yong; Palmieri, Frank L.; Wohl, Christopher J.; Jiang, Xiaoning

    2016-04-01

    In this paper, a piezoelectric sensor with a floating element was developed for shear stress measurement. The piezoelectric sensor was designed to detect the pure shear stress, suppressing effects of normal stress components, by applying opposite poling vectors to the piezoelectric elements. The sensor was first calibrated in the lab by applying shear forces where it demonstrated high sensitivity to shear stress (91.3 +/- 2.1 pC/Pa) due to the high piezoelectric coefficients of 0.67Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 (PMN-33%PT, d31=-1330 pC/N). The sensor also exhibited negligible sensitivity to normal stress (less than 1.2 pC/Pa) because of the electromechanical symmetry of the device. The usable frequency range of the sensor is up to 800 Hz.

  3. Stress fractures in young athletes.

    PubMed

    Orava, S; Jormakka, E; Hulkko, A

    1981-01-01

    In a series of 16 cases of stress fractures in 15-year-old and younger athletes 8 fractures occurred in boys and 8 in girls. There were no differences between the sexes in the athletes' training habits. Ten of the fractures were located at the tibia, seven at its upper third and three at the lower part of the bone. Three fractures were found in the fibula, in the metatarsal bones two stress fractures and in the femur one stress fracture. Most stress fractures were caused by endurance type sports. The daily training distances were not particularly high at the time of the onset of the symptoms. In most cases the diagnosis was based on a radiological evaluation. A sufficiently long pause from all athletic activity was enough treatment. Stress fractures in children are very uncommon. PMID:7295000

  4. Approximation auto-coherente a deux particules, pseudogap et supraconductivite dans le modele de Hubbard attractif

    NASA Astrophysics Data System (ADS)

    Allen, Steve

    2000-10-01

    Dans cette these nous presentons une nouvelle methode non perturbative pour le calcul des proprietes d'un systeme de fermions. Notre methode generalise l'approximation auto-coherente a deux particules proposee par Vilk et Tremblay pour le modele de Hubbard repulsif. Notre methode peut s'appliquer a l'etude du comportement pre-critique lorsque la symetrie du parametre d'ordre est suffisamment elevee. Nous appliquons la methode au probleme du pseudogap dans le modele de Hubbard attractif. Nos resultats montrent un excellent accord avec les donnees Monte Carlo pour de petits systemes. Nous observons que le regime ou apparait le pseudogap dans le poids spectral a une particule est un regime classique renormalise caracterise par une frequence caracteristique des fluctuations supraconductrices inferieure a la temperature. Une autre caracteristique est la faible densite de superfluide de cette phase demontrant que nous ne sommes pas en presence de paires preformees. Les resultats obtenus semblent montrer que la haute symetrie du parametre d'ordre et la bidimensionalite du systeme etudie elargissent le domaine de temperature pour lequel le regime pseudogap est observe. Nous argumentons que ce resultat est transposable aux supraconducteurs a haute temperature critique ou le pseudogap apparait a des' temperatures beaucoup plus grandes que la temperature critique. La forte symetrie dans ces systemes pourraient etre reliee a la theorie SO(5) de Zhang. En annexe, nous demontrons un resultat tout recent qui permettrait d'assurer l'auto-coherence entre les proprietes a une et a deux particules par l'ajout d'une dynamique au vertex irreductible. Cet ajout laisse entrevoir la possibilite d'etendre la methode au cas d'une forte interaction.

  5. La prévention des blessures dans les terrains de jeux

    PubMed Central

    Fuselli, Pamela; Yanchar, Natalie L

    2012-01-01

    RÉSUMÉ Dans un climat d’inquiétude croissante à l’égard de l’obésité juvénile et de l’inactivité, les terrains de jeux permettent aux enfants d’être actifs. Ils comportent toutefois aussi des risques, les blessures causées par des chutes étant de loin les plus courants. Les recherches démontrent la possibilité de réduire les blessures dans les terrains de jeux si on abaisse la hauteur des structures de jeu et si on utilise des surfaces molles et profondes pour amortir les chutes. L’Association canadienne de normalisation a publié des normes volontaires qu’elle a mises à jour plusieurs fois pour tenir compte de ces risques. Afin de contribuer à les réduire, les parents peuvent respecter des stratégies simples. Le présent document de principes souligne le fardeau des blessures subies dans les terrains de jeux. Il procure également aux parents et aux dispensateurs de soins des occasions de réduire l’incidence et la gravité des blessures grâce à l’éducation et à la défense d’intérêts, ainsi que de mettre en œuvre des normes de sécurité probantes et des stratégies plus sécuritaires dans les terrains de jeux locaux. Enfin, il remplace le document de principes de la Société canadienne de pédiatrie publié en 2002 sur le sujet.

  6. Earthquake stress drops, ambient tectonic stresses and stresses that drive plate motions

    USGS Publications Warehouse

    Hanks, T.C.

    1977-01-01

    A variety of geophysical observations suggests that the upper portion of the lithosphere, herein referred to as the elastic plate, has long-term material properties and frictional strength significantly greater than the lower lithosphere. If the average frictional stress along the non-ridge margin of the elastic plate is of the order of a kilobar, as suggested by the many observations of the frictional strength of rocks at mid-crustal conditions of pressure and temperature, the only viable mechanism for driving the motion of the elastic plate is a basal shear stress of several tens of bars. Kilobars of tectonic stress are then an ambient, steady condition of the earth's crust and uppermost mantle. The approximate equality of the basal shear stress and the average crustal earthquake stress drop, the localization of strain release for major plate margin earthquakes, and the rough equivalence of plate margin slip rates and gross plate motion rates suggest that the stress drops of major plate margin earthquakes are controlled by the elastic release of the basal shear stress in the vicinity of the plate margin, despite the existence of kilobars of tectonic stress existing across vertical planes parallel to the plate margin. If the stress differences available to be released at the time of faulting are distributed in a random, white fasbion with a mean-square value determined by the average earthquake stress drop, the frequency of occurrence of constant stress drop earthquakes will be proportional to reciprocal faulting area, in accordance with empirically known frequency of occurrence statistics. ?? 1977 Birkha??user Verlag.

  7. Criterion validation of a stress measure: the Stress Overload Scale.

    PubMed

    Amirkhan, James H; Urizar, Guido G; Clark, Sarah

    2015-09-01

    Validating stress scales poses problems beyond those of other psychological measures. Here, 3 studies were conducted to address those problems and assess the criterion validity of scores from a new theory-derived measure, the Stress Overload Scale (SOS; Amirkhan, 2012). In Study 1, the SOS was tested for its ability to predict postsemester illness in a sample of college students (n = 127). Even with precautions to minimize criterion contamination, scores were found to predict health problems in the month following a final exam on all of 5 different criteria. In Study 2, a community sample (n = 231) was used to test the SOS' ability to differentiate people in stressful circumstances from those in more relaxed contexts. SOS scores demonstrated excellent sensitivity (96%) and specificity (100%) in this general population application. In Study 3, the SOS was tested for its ability to differentiate salivary cortisol responses to a laboratory stressor in a group of pregnant women (n = 40). High scores were found to be associated with a blunted cortisol response, which is indicative of HPA-axis overload and typical of persons suffering chronic stress and stress-related pathology. Across all 3 studies, despite variations in the stressor, criterion, population, and methods, SOS scores emerged as valid indicators of stress. However, each study also introduced new problems that beg additional corrective steps in future stress-scale validity tests. These strategies, and the SOS' utility as a research and diagnostic tool in varied applications and populations, are discussed. PMID:25642927

  8. Residual stresses and stress corrosion cracking in pipe fittings

    SciTech Connect

    Parrington, R.J.; Scott, J.J.; Torres, F.

    1994-06-01

    Residual stresses can play a key role in the SCC performance of susceptible materials in PWR primary water applications. Residual stresses are stresses stored within the metal that develop during deformation and persist in the absence of external forces or temperature gradients. Sources of residual stresses in pipe fittings include fabrication processes, installation and welding. There are a number of methods to characterize the magnitude and orientation of residual stresses. These include numerical analysis, chemical cracking tests, and measurement (e.g., X-ray diffraction, neutron diffraction, strain gage/hole drilling, strain gage/trepanning, strain gage/section and layer removal, and acoustics). This paper presents 400 C steam SCC test results demonstrating that residual stresses in as-fabricated Alloy 600 pipe fittings are sufficient to induce SCC. Residual stresses present in as-fabricated pipe fittings are characterized by chemical cracking tests (stainless steel fittings tested in boiling magnesium chloride solution) and by the sectioning and layer removal (SLR) technique.

  9. Stress, stress-induced cortisol responses, and eyewitness identification performance.

    PubMed

    Sauerland, Melanie; Raymaekers, Linsey H C; Otgaar, Henry; Memon, Amina; Waltjen, Thijs T; Nivo, Maud; Slegers, Chiel; Broers, Nick J; Smeets, Tom

    2016-07-01

    In the eyewitness identification literature, stress and arousal at the time of encoding are considered to adversely influence identification performance. This assumption is in contrast with findings from the neurobiology field of learning and memory, showing that stress and stress hormones are critically involved in forming enduring memories. This discrepancy may be related to methodological differences between the two fields of research, such as the tendency for immediate testing or the use of very short (1-2 hours) retention intervals in eyewitness research, while neurobiology studies insert at least 24 hours. Other differences refer to the extent to which stress-responsive systems (i.e., the hypothalamic-pituitary-adrenal axis) are stimulated effectively under laboratory conditions. The aim of the current study was to conduct an experiment that accounts for the contemporary state of knowledge in both fields. In all, 123 participants witnessed a live staged theft while being exposed to a laboratory stressor that reliably elicits autonomic and glucocorticoid stress responses or while performing a control task. Salivary cortisol levels were measured to control for the effectiveness of the stress induction. One week later, participants attempted to identify the thief from target-present and target-absent line-ups. According to regression and receiver operating characteristic analyses, stress did not have robust detrimental effects on identification performance. Copyright © 2016 John Wiley & Sons, Ltd. © 2016 The Authors Behavioral Sciences & the Law Published by John Wiley & Sons Ltd. PMID:27417874

  10. Residual stresses in welded plates

    NASA Technical Reports Server (NTRS)

    Bernstein, Edward L.

    1994-01-01

    The purpose of this project was to develop a simple model which could be used to study residual stress. The mechanism that results in residual stresses in the welding process starts with the deposition of molten weld metal which heats the immediately adjacent material. After solidification of weld material, normal thermal shrinkage is resisted by the adjacent, cooler material. When the thermal strain exceeds the elastic strain corresponding to the yield point stress, the stress level is limited by this value, which decreases with increasing temperature. Cooling then causes elastic unloading which is restrained by the adjoining material. Permanent plastic strain occurs, and tension is caused in the region immediately adjacent to the weld material. Compression arises in the metal farther from the weld in order to maintain overall static equilibrium. Subsequent repair welds may add to the level of residual stresses. The level of residual stress is related to the onset of fracture during welding. Thus, it is of great importance to be able to predict the level of residual stresses remaining after a weld procedure, and to determine the factors, such as weld speed, temperature, direction, and number of passes, which may affect the magnitude of remaining residual stress. It was hoped to use traditional analytical modeling techniques so that it would be easier to comprehend the effect of these variables on the resulting stress. This approach was chosen in place of finite element methods so as to facilitate the understanding of the physical processes. The accuracy of the results was checked with some existing experimental studies giving residual stress levels found from x-ray diffraction measurements.

  11. Types of Stresses Experienced by Professionals.

    ERIC Educational Resources Information Center

    Gadzella, Bernadette M.; And Others

    This study was conducted to examine the types of stresses experienced by professionals. Subjects were 56 persons enrolled in graduate classes who completed the Tennessee Stress Scale-L, Work Related Stress Inventory for Professionals. Besides the Total stress score, the instrument produced three subscale scores: Stress Producers, Coping…

  12. Distributional Stress Regularity: A Corpus Study

    ERIC Educational Resources Information Center

    Temperley, David

    2009-01-01

    The regularity of stress patterns in a language depends on "distributional stress regularity", which arises from the pattern of stressed and unstressed syllables, and "durational stress regularity", which arises from the timing of syllables. Here we focus on distributional regularity, which depends on three factors. "Lexical stress patterning"…

  13. Children and Stress: Indications, Implications and Interventions.

    ERIC Educational Resources Information Center

    Gold, Joshua M.

    Stress is a part of the normal process of growing and developing for children. A stress situation is composed of anxiety and stress. If coping strategies are inadequate, depression can result. Four categories of stress include time, anticipatory, situational, and encounter stress. It is important to recognize unsuccessful defense mechanisms…

  14. Diachrony and Synchrony in Word Stress.

    ERIC Educational Resources Information Center

    Roca, Iggy

    1990-01-01

    Reexamines the issue of Spanish nonverbal word stress, illustrates two basic generalizations about primary word stress, develops the conclusion that penultimate stress is unmarked, examines the relationship between Latin stress and its Spanish descendant, and contrasts the stress systems of Latin and Spanish. (32 references) (GLR)

  15. Franz Xaver von Zach et l'astronomie dans la France méridionale

    NASA Astrophysics Data System (ADS)

    Brosche, Peter; Débarbat, Suzanne

    Le baron Franz Xaver von Zach, né à Pest (Hongrie), a fait ses études notamment en France et en Angleterre. En 1786 le duc de Saxe-Gotha, Ernst II, lui demande de créer son observatoire de Seeberg. La même année ils se rendent dans le sud de la France, à Hyères à cette occasion, une des tours du mur d'enceinte de la ville est transformée en observatoire. En 1809, Zach et la duchesse régnante viennent près de Marseille et, lors de plusieurs voyages dans le sud de la France. Zach exécute des travaux géodésiques et astronomiques. Dans son "Journal", il mentionne les astronomes français, notamment ceux de la France méridonale auxquels il apporte son soutien. Pons devient, sur sa recommandation, astronome royal de la duchesse de Lucca, épouse du "roi d'Etrurie".

  16. Autofrettage: Stress distribution under load and retained stresses after depressurization

    NASA Astrophysics Data System (ADS)

    Avitzur, Boaz

    1992-07-01

    There is a long-standing interest in developing a capability to predict the distribution of retained stresses in thick-walled tubes after the removal of an internal pressure-post autofrettage. In this report, four different methods of calculating such stresses are presented and compared. The methods presented are based on the following assumed yield criteria and deformation conditions: (1) Tresca's yield criterion; (2) Tresca's yield criterion 2/3; (3) Mises' yield criterion in plane-stress; and (4) Mises' yield criterion in plane-strain.

  17. Earthquake stress triggers, stress shadows, and seismic hazard

    USGS Publications Warehouse

    Harris, R.A.

    2000-01-01

    Many aspects of earthquake mechanics remain an enigma at the beginning of the twenty-first century. One potential bright spot is the realization that simple calculations of stress changes may explain some earthquake interactions, just as previous and ongoing studies of stress changes have begun to explain human- induced seismicity. This paper, which is an update of Harris1, reviews many published works and presents a compilation of quantitative earthquake-interaction studies from a stress change perspective. This synthesis supplies some clues about certain aspects of earthquake mechanics. It also demonstrates that much work remains to be done before we have a complete story of how earthquakes work.

  18. Stress in dilute suspensions

    NASA Technical Reports Server (NTRS)

    Passman, Stephen L.

    1989-01-01

    Generally, two types of theory are used to describe the field equations for suspensions. The so-called postulated equations are based on the kinetic theory of mixtures, which logically should give reasonable equations for solutions. The basis for the use of such theory for suspensions is tenuous, though it at least gives a logical path for mathematical arguments. It has the disadvantage that it leads to a system of equations which is underdetermined, in a sense that can be made precise. On the other hand, the so-called averaging theory starts with a determined system, but the very process of averaging renders the resulting system underdetermined. A third type of theory is proposed in which the kinetic theory of gases is used to motivate continuum equations for the suspended particles. This entails an interpretation of the stress in the particles that is different from the usual one. Classical theory is used to describe the motion of the suspending medium. The result is a determined system for a dilute suspension. Extension of the theory to more concentrated systems is discussed.

  19. Stress, Metabolism and Cancer

    PubMed Central

    Repasky, Elizabeth A.; Eng, Jason; Hylander, Bonnie L.

    2015-01-01

    The potential for immune cells to control cancers has been recognized for many decades, but only recently has real excitement begun to spread through the oncology community following clear evidence that therapeutic blockade of specific immune-suppressive mechanisms is enough to make a real difference in survival for patients with several different advanced cancers. However, impressive and encouraging as these new clinical data are, it is clear that more effort should be devoted toward understanding the full spectrum of factors within cancer patients, which have the potential to block or weaken antitumor activity by immune cells. The goal of this brief review is to highlight recent literature revealing interactive stress and metabolic pathways, particularly those mediated by the sympathetic nervous system, which may conspire to block immune cells from unleashing their full killing potential. There is exciting new information regarding the role of neurogenesis by tumors and adrenergic signaling in cancer progression (including metabolic changes associated with cachexia and lipolysis) and in regulation of immune cell function and differentiation. However, much more work is needed to fully understand how the systemic metabolic effects mediated by the brain and nervous system can be targeted for therapeutic efficacy in the setting of immunotherapy and other cancer therapies. PMID:25815849

  20. [Nutrition and stress].

    PubMed

    Tappy, L; Berger, M M; Chiolero, R L

    2000-11-01

    Acute illness induces major physiological responses, which favor the adaptation of the organism to stress and injury. The metabolic response plays key roles in maintenance of vital functions and promotion of the healing mechanisms. All the components of energy expenditure are modified, particularly the resting metabolism. The regulation of carbohydrate metabolism is also markedly altered. Such patients are characterized by fasting and postprandial hyperglycemia, insulin resistance, and by a stimulation of the hepatic glucose production in fasted and fed states. Lipolysis and increased fat oxidation are typically observed. Ketogenesis processes are inhibited, concurring to alter the adaptation to starvation. Protein turnover is stimulated with a preponderance of the catabolic processes, even during full nutritional support. This induces a state of resistance to feeding, leading to a progressive depletion of the fat free mass. Such progressive tissue catabolism cannot be reversed by hypercaloric nutrition or growth factors. Specific nutrients (aminoacids, micronutrients, PUFA) may offer interesting perspectives in stimulating immunity, improving the antioxidant balance or modulating the inflammatory response. PMID:11139659

  1. Stress Management by Biofeedback

    NASA Technical Reports Server (NTRS)

    1997-01-01

    In the 1980's, Dr. Patrick Doyle served on a project to train U.S. astronauts at Johnson Space Center in biofeedback techniques to control anxiety and hypertension. Traditional biofeedback concepts were found to be too mundane, repetitive and boring, so Doyle developed Bio-Games with more interesting and involved formats. The first product, Bio-Ball, is an interactive, multimedia baseball video game that is played by relaxing in order to hit the ball. Gradually the player is able to relax at will, and with practice is able to apply the skills to real-life situations. Doyle has since gone on to create a number of biofeedback games marketed by Creative MultiMedia Inc. including Bio-Golf, Clutch City, and Pachyderm. Stress-busting screen savers are also being marketed under the Buddies series. In addition to being used in the corporate world, Bio-Games have been recognized by the Starbright Foundation which focuses on improving the total hospital environments of critically injured and chronically-ill children.

  2. Pattern Driven Stress Localization

    NASA Astrophysics Data System (ADS)

    Croll, Andrew; Crosby, Alfred

    2010-03-01

    The self-assembly of patterns from isotropic initial states is a major driver of modern soft-matter research. This avenue of study is directed by the desire to understand the complex physics of the varied structures found in Nature, and by technological interest in functional materials that may be derived through biomimicry. In this work we show how a simple striped phase can respond with significant complexity to an appropriately chosen perturbation. In particular, we show how a buckled elastic plate transitions into a state of stress localization using a simple, self-assembled variation in surface topography. The collection of topographic boundaries act in concert to change the state from isotropic sinusoidal wrinkles, to sharp folds or creases separated by relatively flat regions. By varying the size of the imposed topographic pattern or the wavelength of the wrinkles, we construct a state diagram of the system. The localized state has implications for both biological systems, and for the control of non-linear pattern formation.

  3. Stress Can Be a Friend: Approaches to Producing Good Stresses That Reduce and Control Bad Stresses.

    ERIC Educational Resources Information Center

    Demery, Marie

    Individuals can produce good stresses that will inhibit or eliminate the bad stresses of anxiety, depression, resentment, and hopelessness. This can be accomplished as individuals learn to include in their lifestyles these nine approaches: self-talk, commitment, self-control, challenge, interpersonal relations, time management, relaxation,…

  4. Interactive effects of stress reactivity and usual stress on adolescents cardiovascular health

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adolescents experience stressful situations at high rates during school. Psychological stress is associated with the progression of cardiovascular disease (CVD). The diathesis-stress model suggests that youth experiencing the greatest cumulative stress are at greatest risk for developing antecedents...

  5. Effets Seebeck et Nernst dans les cuprates: Etude de la reconstruction de la surface de Fermi sous champ magnetique intense

    NASA Astrophysics Data System (ADS)

    Laliberte, Francis

    2010-06-01

    Ce memoire presente des mesures de transport thermoelectrique, les effets Seebeck et Nernst, dans une serie d'echantillons de supraconducteurs a haute temperature critique. Des resultats obtenus recemment au Laboratoire National des Champs Magnetiques Intenses a Grenoble sur La1.7Eu0.2Sr0.1 CuO4, La1.675Eu0.2Sr0.125CuO 4, La1.64Eu0.2Sr0.16CuO4, La1.74Eu0.1Sr0.16CuO4 et La 1.4Nd0.4Sr0.2CuO4 sont analyses. Une attention particuliere est accordee aux equations de la theorie semi-classique du transport et leur validite est verifiee. La procedure experimentale et les materiaux utilises pour concevoir les montages de mesures sont expliques en detail. Enfin, un chapitre est dedie a l'explication et l'interpretation des resultats de transport thermoelectrique sur YBa2Cu3O6+delta publies au cours de l'hiver 2010 dans les revues Nature et Physical Review Letters. Les donnees d'effet Seebeck dans les echantillons de La 1.8-x,Eu0.2SrxCuO 4, ou un changement de signe est observe, permettent de conclure a la presence d'une poche d'electrons dans la surface de Fermi qui domine le transport a basse temperature dans la region sous-dopee du diagramme de phase. Cette conclusion est similaire a celle obtenue par des mesures d'effet Hall dans YBa 2Cu3O6+delta et elle cadre bien dans un scenario de reconstruction de la surface de Fermi. Les donnees d'effet Nernst recueillies indiquent que la contribution des fluctuations supraconductrices est limitee a un modeste intervalle de temperature au-dessus de la temperature critique.

  6. A pilot study using the Chinese herbal paste Liu-He-Dan to manage radiodermatitis associated with breast cancer radiotherapy

    PubMed Central

    Zhou, J.; Fang, L.; Xie, H.; Yao, W.X.; Zhou, X.; Xiong, Z.J.

    2015-01-01

    Background During radiotherapy for breast cancer, patients are greatly affected by pain, infection, and delayed healing of wounds caused by radiodermatitis. In the present study, we aimed to determine the efficacy of Liu-He-Dan in treating radiodermatitis. Methods In 26 breast cancer patients who experienced moist decrustation while receiving radiotherapy, 5 g Liu-He-Dan was applied externally once daily after the wound surface had been cleaned and dried. The healing time was recorded, and a Kaplan–Meier survival curve was applied to analyze the treatment course. Meanwhile, a pain assessment using the Numeric Rating Scale (nrs) recorded the pain level experienced by patients after application of the Liu-He-Dan. Results After application of Liu-He-Dan, the average healing time for the surface of the moist decrustation wounds was 14.17 ± 2.03 days (range: 5–22 days). Inflammatory seepage decreased significantly and exudation almost disappeared in 3 days. The pain trend line indicated that the average nrs score declined with treatment in all patients. The average nrs scores at days 1, 4, and 7 were 6.13, 3.62, and 2.58 respectively. After 3 days of treatment, pain was remarkably alleviated in 80.76% of patients. After treatment for 1 week, the pain remission rate was 96.15%, without any obvious adverse reactions. Conclusions Liu-He-Dan was efficacious in treating radiation skin injury with little toxicity and few side effects; the economic efficiency of the treatment was also favourable. The Liu-He-Dan was generally well tolerated by patients. In future, randomized control trials will be established for further observation of the value of Liu-He-Dan in treating radiodermatitis in breast cancer. PMID:26715882

  7. 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

  8. Prenatal Stress, Prematurity, and Asthma.

    PubMed

    Medsker, Brock; Forno, Erick; Simhan, Hyagriv; Celedón, Juan C

    2015-12-01

    Asthma is the most common chronic disease of childhood, affecting millions of children in the United States and worldwide. Prematurity is a risk factor for asthma, and certain ethnic or racial minorities such as Puerto Ricans and non-Hispanic blacks are disproportionately affected by both prematurity and asthma. In this review, we examine current evidence to support maternal psychosocial stress as a putative link between prematurity and asthma, while also focusing on disruption of the hypothalamic-pituitary-adrenal (HPA) axis and immune responses as potential underlying mechanisms for stress-induced "premature asthma." Prenatal stress may cause not only abnormalities in the HPA axis but also epigenetic changes in the fetal glucocorticoid receptor gene (NR3C1), leading to impaired glucocorticoid metabolism. Moreover, maternal stress can alter fetal cytokine balance, favoring TH2 (allergic) immune responses characteristic of atopic asthma: interleukin 6 (IL-6), which has been associated with premature labor, can promote TH2 responses by stimulating production of IL-4 and IL-13. Given a link among stress, prematurity, and asthma, future research should include birth cohorts aimed at confirming and better characterizing "premature asthma." If confirmed, clinical trials of prenatal maternal stress reduction would be warranted to reduce the burden of these common comorbidities. While awaiting the results of such studies, sound policies to prevent domestic and community violence (eg, from firearms) are justified, not only by public safety but also by growing evidence of detrimental effects of violence-induced stress on psychiatric and somatic health. PMID:26676148

  9. RESIDUAL STRESSES IN 3013 CONTAINERS

    SciTech Connect

    Mickalonis, J.; Dunn, K.

    2009-11-10

    The DOE Complex is packaging plutonium-bearing materials for storage and eventual disposition or disposal. The materials are handled according to the DOE-STD-3013 which outlines general requirements for stabilization, packaging and long-term storage. The storage vessels for the plutonium-bearing materials are termed 3013 containers. Stress corrosion cracking has been identified as a potential container degradation mode and this work determined that the residual stresses in the containers are sufficient to support such cracking. Sections of the 3013 outer, inner, and convenience containers, in both the as-fabricated condition and the closure welded condition, were evaluated per ASTM standard G-36. The standard requires exposure to a boiling magnesium chloride solution, which is an aggressive testing solution. Tests in a less aggressive 40% calcium chloride solution were also conducted. These tests were used to reveal the relative stress corrosion cracking susceptibility of the as fabricated 3013 containers. Significant cracking was observed in all containers in areas near welds and transitions in the container diameter. Stress corrosion cracks developed in both the lid and the body of gas tungsten arc welded and laser closure welded containers. The development of stress corrosion cracks in the as-fabricated and in the closure welded container samples demonstrates that the residual stresses in the 3013 containers are sufficient to support stress corrosion cracking if the environmental conditions inside the containers do not preclude the cracking process.

  10. Stress Relaxation of Magnetorheological Fluids

    NASA Astrophysics Data System (ADS)

    Li, W. H.; Chen, G.; Yeo, S. H.; Du, H.

    In this paper, the experimental and modeling study and analysis of the stress relaxation characteristics of magnetorheological (MR) fluids under step shear are presented. The experiments are carried out using a rheometer with parallel-plate geometry. The applied strain varies from 0.01% to 100%, covering both the pre-yield and post-yield regimes. The effects of step strain, field strength, and temperature on the stress modulus are addressed. For small step strain ranges, the stress relaxation modulus G(t,γ) is independent of step strain, where MR fluids behave as linear viscoelastic solids. For large step strain ranges, the stress relaxation modulus decreases gradually with increasing step strain. Morever, the stress relaxation modulus G(t,γ) was found to obey time-strain factorability. That is, G(t,γ) can be represented as the product of a linear stress relaxation G(t) and a strain-dependent damping function h(γ). The linear stress relaxation modulus is represented as a three-parameter solid viscoelastic model, and the damping function h(γ) has a sigmoidal form with two parameters. The comparison between the experimental results and the model-predicted values indicates that this model can accurately describe the relaxation behavior of MR fluids under step strains.

  11. Employee occupational stress in banking.

    PubMed

    Michailidis, Maria; Georgiou, Yiota

    2005-01-01

    Occupational stress literature emphasizes the importance of assessment and management of work related stress. The recognition of the harmful physical and psychological effects of stress on both individuals and organizations is widely studied in many parts of the world. However, in other regions such research is only at the introductory stages. The present study examines occupational stress of employees in the banking sector. A sample of 60 bank employees at different organizational levels and educational backgrounds was used. Data collection utilized the Occupational Stress Indicator (OSI). Results of data analysis provided evidence that employees' educational levels affect the degree of stress they experience in various ways. Bank employees cannot afford the time to relax and "wind down" when they are faced with work variety, discrimination, favoritism, delegation and conflicting tasks. The study also shows the degree to which some employees tend to bring work-related problems home (and take family problems to work) depends on their educational background, the strength of the employees' family support, and the amount of time available for them to relax. Finally, the drinking habits (alcohol) of the employees were found to play a significant role in determining the levels of occupational stress. PMID:15860902

  12. Plant responses to water stress

    PubMed Central

    Kar, Rup Kumar

    2011-01-01

    Terrestrial plants most often encounter drought stress because of erratic rainfall which has become compounded due to present climatic changes.Responses of plants to water stress may be assigned as either injurious change or tolerance index. One of the primary and cardinal changes in response to drought stress is the generation of reactive oxygen species (ROS), which is being considered as the cause of cellular damage. However, recently a signaling role of such ROS in triggering the ROS scavenging system that may confer protection or tolerance against stress is emerging. Such scavenging system consists of antioxidant enzymes like SOD, catalase and peroxidases, and antioxidant compounds like ascorbate, reduced glutathione; a balance between ROS generation and scavenging ultimately determines the oxidative load. As revealed in case of defence against pathogen, signaling via ROS is initiated by NADPH oxidase-catalyzed superoxide generation in the apoplastic space (cell wall) followed by conversion to hydrogen peroxide by the activity of cell wall-localized SOD. Wall peroxidase may also play role in ROS generation for signaling. Hydrogen peroxide may use Ca2+ and MAPK pathway as downstream signaling cascade. Plant hormones associated with stress responses like ABA and ethylene play their role possibly via a cross talk with ROS towards stress tolerance, thus projecting a dual role of ROS under drought stress. PMID:22057331

  13. A stress-free model for residual stress assessment using thermoelastic stress analysis

    NASA Astrophysics Data System (ADS)

    Howell, Geoffrey; Dulieu-Barton, Janice M.; Achintha, Mithila; Robinson, Andrew F.

    2015-03-01

    Thermoelastic Stress Analysis (TSA) has been proposed as a method of obtaining residual stresses. The results of a preliminary study demonstrated that when Al-2024 plate containing holes that were plastically deformed by cold expansion process to 2% and 4% strain the thermoelastic response in the material around the hole was different to that obtained from a plate that had not experienced any plastic cold expansion (i.e. a reference specimen). This observation provides an opportunity for obtaining residual stresses based on TSA data. In many applications a reference specimen (i.e. residual stress free specimen) may not be available for comparison, so a synthetic, digital bitmap has been proposed as an alternative. An elastic finite element model is created using commercially available software Abaqus/Standard and the resultant stress field is extracted. The simulated stress field from the model is mapped onto a grid that matches the TSA pixel data from a physical reference specimen. This stress field is then converted to a ΔT/T field that can be compared to the full-field TSA data. When the reference experimental data is subtracted from the, bitmap dataset the resultant ΔT/T field is approximately zero. Further work proposes replacing the experimental reference data with that from specimens that have undergone cold expansion with the aim of revealing the regions affected by residual stress through a departure from zero in the resultant stress field. The paper demonstrates the first steps necessary for deriving the residual stresses from a general specimen using TSA.

  14. Les superpolynomes symetriques dans les problemes a plusieurs corps de la mecanique quantique supersymetrique

    NASA Astrophysics Data System (ADS)

    Desrosiers, Patrick

    S'inspirant de la supersymetrie, on construit dans cette these une nouvelle generalisation de la theorie des fonctions symetriques. Une theorie physique est supersymetrique si: (1) elle contient des bosons (particules de spin entier) et des fermions (particules de spin demi-entier); (2) elle reste inchangee suite a une transformation des bosons en fermions et vice versa. Les fonctions symetriques dans le superespace (superfonctions symetriques) incorporent a la fois des variables commutatives (bosoniques) et anticommutatives (fermioniques). Ces dernieres engendrent une algebre de Grassmann. Une superfonction symetrique est invariante sous l'echange simultane des variables bosoniques et fermioniques (action diagonale du groupe symetrique); elle se caracterise par une superpartition, i.e., une juxtaposition appropriee de partitions usuelles d'entiers non negatifs. On utilise deux approches dans l'elaboration de la theorie des superfonctions symetriques: l'une provient de la combinatoire et l'autre, de la physique. Suivant la premiere approche, on obtient l'extension des elements standards de la theorie des fonctions symetriques fonctions monomiales, fonctions symetriques elementaires, fonctions completement symetriques, series de puissances, fonctions generatrices et formules de Cauchy. On demontre egalement qu'il existe une extension naturelle, a un parametre, du produit scalaire combinatoire defini par l'orthogonalite des series de puissances dans le superespace. La seconde approche consiste a resoudre des problemes a N corps de la mecanique quantique supersymetrique. On etudie les extensions supersymetriques des modeles Calogero-Moser-Sutherland (CMS), lesquels decrivent l'evolution de particules dont le potentiel d'inter action est proportionnel a l'inverse du carre de la distance separant les particules. Deux modeles supersymetriques CMS sont resolus: trigonometrique (sur un cercle) et rationnel (sur une ligne) avec confinement harmonique. Leurs fonctions d

  15. Les bisphosphonates dans le traitement de l’ostéoporose

    PubMed Central

    Brown, Jacques P.; Morin, Suzanne; Leslie, William; Papaioannou, Alexandra; Cheung, Angela M.; Davison, Kenneth S.; Goltzman, David; Hanley, David Arthur; Hodsman, Anthony; Josse, Robert; Jovaisas, Algis; Juby, Angela; Kaiser, Stephanie; Karaplis, Andrew; Kendler, David; Khan, Aliya; Ngui, Daniel; Olszynski, Wojciech; Ste-Marie, Louis-Georges; Adachi, Jonathan

    2014-01-01

    Résumé Objectif Exposer l’efficacité et les risques du traitement par les bisphosphonates dans la prise en charge de l’ostéoporose et décrire les patients qui seraient de bons candidats aux congés thérapeutiques. Qualité des données Une recherche dans MEDLINE (PubMed, jusqu’au 31 décembre 2012) a permis de relever les publications pertinentes pour l’inclusion. La plupart des données probantes citées sont de niveau II (tirées d’essais non randomisés, de cohorte et d’autres essais comparatifs). Message principal L’efficacité des bisphosphonates de premier recours homologués pour la prévention des fractures a été éprouvée dans le cadre d’essais cliniques randomisés et contrôlés. Cependant, l’usage clinique répandu et prolongé des bisphosphonates a donné lieu à des rapports de manifestations indésirables rares, mais graves. L’ostéonécrose maxillaire et les fractures atypiques sous-trochantériennes ou diaphysaires du fémur seraient liées à l’emploi des bisphosphonates dans le traitement de l’ostéoporose, mais ces manifestations sont extrêmement rares et lorsqu’elles surviennent, elles sont accompagnées d’autres comorbidités ou de l’emploi concomitant de médicaments. Les congés thérapeutiques ne peuvent être envisagés que chez les patients à faible risque et dans un groupe restreint de patients dont le risque de fracture est modéré après un traitement de 3 à 5 ans. Conclusion Lorsque les bisphosphonates sont prescrits à des patients dont le risque de fracture est élevé, leur effet de prévention des fractures l’emporte de loin sur leurs torts potentiels. Chez les patients qui prennent des bisphosphonates depuis 3 à 5 ans, il faut réévaluer le besoin de poursuivre le traitement.

  16. Manipulation coherente de qubits de spin dans une boite quantique triple

    NASA Astrophysics Data System (ADS)

    Gaudreau, Louis

    Nous presentons dans cette these une etude detaillee du moment magnetique intrinseque de l'electron, i.e. le spin electronique, incluant la manipulation quantique coherente des etats de spin de trois electrons couples. A cette fin, nous utilisons des boites quantiques laterales pour confiner les electrons. Ces nano-structures, d'une grandeur autour de 1 pm, permettent de confiner un nombre precis d'electrons de facon controlee, allant jusqu'a zero electrons. Les developpements technologiques et d'ingeniosite durant la derniere decennie ont permis de coupler trois boites quantiques, ainsi l'interaction entre plusieurs electrons confines peut etre controlee comme par exemple le couplage quantique tunnel et l'interaction d'echange entre les spins de chacun d'entre eux. A l'aide de boites quantiques couplees, il est possible de realiser des experiences dans plusieurs domaines de la physique moderne : les etats up et down du spin des electrons confines peuvent etre utilisees comme etats quantiques binaires (qubits) dans le domaine de l'informatique quantique, la non-localite quantique peut etre testee en separant spatialement deux electrons enchevetres, il est possible de creer des 'courants de spin enchevetres' utiles en spintronique, et bien d'autres. La manipulation coherente des etats de spin du systeme a trois electrons se fait de facon purement electrique grace a des pulses a haute frequence qui permettent d'augmenter le couplage entre les electrons et de faire la mesure de l'etat resultant apres la manipulation. Nous utilisons l'interaction hyperfine entre les spins des electrons et ceux des noyaux du cristal dans lequel ils resident pour creer les rotations quantiques entre les etats, notamment les etats |Q +3/2> et (D+1/2>. Les resultats obtenus indiquent un temps de coherence de l'ordre de 10 ns. Ces experiences demontrent un niveau de controle sans precedant de boites quantiques triples et pavent la voie vers des nano-structures plus sophistiquees dans

  17. Transport dans l'hélium 3 polarisé par pompage optique

    NASA Astrophysics Data System (ADS)

    Lhuillier, C.; Leduc, M.

    Optical pumping is, in the case of helium 3, a useful method for polarizing the nuclear spins of the gas. Substantial orientation rates can be now achieved using tunable infrared lasers. Large changes in the macroscopic behaviour of the helium 3 fluid occur as a consequence of the polarization of the nuclei, provided the temperature is low enough, in spite of the small nuclear magnetic moment. These effects result both from interactions and statistics and are subtle consequences of the indistinguishability of particles and of the symmetrization principle in quantum mechanics. One explains in this article the expected changes for the viscosity and the heat conduction in the gas below a few kelvins. Furthermore, one shows that the transport of spin magnetization in polarized helium 3 (3He↑) has a propagative character at low temperature, giving rise to collective oscillatory modes : the transverse spin waves. One describes a recent experiment which proved the existence of these waves and allowed measuring their quality factor. Observations and theoretical predictions are in good agreement. Le pompage optique constitue, dans le cas de l'hélium 3, une méthode commode pour polariser les spins nucléaires du gaz. Des taux d'orientation notables peuvent être maintenant réalisés grâce aux lasers accordables dans l'infrarouge. Des changements importants de comportement macroscopique du fluide d'hélium 3 se produisent sous l'effet de la polarisation des noyaux, à condition que la température soit suffisamment basse, et ceci malgré la petitesse du moment magnétique nucléaire ; il s'agit là d'effets conjugués d'interaction et de statistique, manifestations subtiles de l'indiscernabilité des particules et du principe de symétrisation en mécanique quantique. On explique dans cet article les modifications attendues pour la viscosité et la conduction de la chaleur dans le gaz en dessous de quelques kelvins. De plus, on montre que le transport de spin dans l

  18. Les reconstructions acétabulaires dans les prothèses totales de hanche

    PubMed Central

    Zejjari, Hassane; Louaste, Jamal; Cherrad, Taoufik; Bousbae, Hicham; Kasmaoui, Housseine; Amhajji, Larbi; Rachid, Khalid

    2015-01-01

    La chirurgie de reconstruction acétabulaire est une technique qui consiste à combler les pertes de substance osseuse siégeant au niveau du cotyle. Il s'agit d'une étude rétrospective de 15 patients (16 cotyles), sur une période de 6 ans (2006- 2012). Dans douze cas il s'agissait de prothèse totales de la hanche de première intention et dans quatre cas il s'agissait de reprise cotyloïdienne de PTH. L’évaluation clinique préopératoire et postopératoire de tous nos patients a été effectuée par le score de Postel et Merle d'Aubigné. L’évaluation des pertes de substances osseuse du cotyle a été classée selon la classification de Paprosky. L’âge moyen de nos patients au moment de l'intervention a été de 57 ans avec des extrêmes allant de 20 ans à 76 ans. La greffe osseuse a été utilisée chez 12 de nos patients. La reconstruction prothétique a été utilisée chez 8 patients (anneau de Kerboul dans six cas et anneau de Burch-Schneider dans deux cas). Recul post opératoire moyen a été de 56 mois. L’évaluation radiologique a été basée sur les clichés radiologiques du bassin de face strict ainsi que des radiographies de la hanche opérée de face prenant la totalité de la prothèse. Nos résultats cliniques et radiologiques ont été jugé bon à très bon dans la majorité des cas. Pour nous, nous optant pour le recentrage-reconstruction car c'est lui qui s'approche le plus de l'anatomie et de la biomécanique normale de la hanche. PMID:26955415

  19. Raman stress sensor for localized stress measurements in composite laminates

    NASA Astrophysics Data System (ADS)

    Arjyal, Bish; Galiotis, Costas

    1995-09-01

    A new stress/strain sensor for localized measurements in polymer based composites, has been developed and tested. The stress/strain dependent property is the frequency of the atomic vibrations of reinforcing fibers which can be proved with laser Raman spectroscopy. Measurements can be conducted in reinforcing fibers near the surface of laminates. For measurements in the bulk of composites, the exciting laser light has to be transported to the reinforcing fibers via an embedded fiber optic cable. The backscattered light is transmitted through the same fiber optic and is sent to the Raman spectrometer for analysis. The effect of the direction of the fiber optic cable with respect to the axis of the reinforcing fibers is examined. Finally, the relationships between the local fiber stress or strain obtained from the Raman sensor and the far field stress or strain measured conventionally, are established.

  20. Stressing The Person: Legal and Everyday Person Attributions Under Stress

    PubMed Central

    Kubota, Jennifer T.; Mojdehbakhsh, Rachel; Raio, Candace; Brosch, Tobias; Uleman, Jim S.; Phelps, Elizabeth A.

    2014-01-01

    When determining the cause of a person’s behavior, perceivers often overweigh dispositional explanations and underweigh situational explanations, an error known as the Fundamental Attribution Error (FAE). The FAE occurs in part because dispositional explanations are relatively automatic, whereas considering the situation requires additional cognitive effort. Stress is known to impair the prefrontal cortex and executive functions important for the attribution process. We investigated if stress increases dispositional attributions in common place and legal situations. Experiencing a physiological stressor increased participants’ cortisol, dispositional attributions of common everyday behaviors, and negative evaluations. When determining whether a crime was due to the defendant’s disposition or the mitigating situation, self-reported stress correlated with increased dispositional judgments of defendant’s behavior. These findings indicate that stress may makes people more likely to commit the FAE and less favorable in their evaluations of others both in daily life and when making socially consequential judicial decisions. PMID:25175000

  1. Yield shear stress and disaggregating shear stress of human blood

    NASA Astrophysics Data System (ADS)

    Jung, Jinmu; Lee, Byoung-Kwon; Shin, Sehyun

    2014-05-01

    This review presents two distinct rheological parameters of blood that have the potential to indicate blood circulation adequacy: yield shear stress (YSS) and disaggregating shear stress (DSS). YSS and DSS reflect the strength of red blood cell (RBC) aggregation in suspension under static and dynamic conditions, respectively. YSS, defined as the critical stress to disperse RBC aggregates under static conditions, was found to be dependent upon hematocrit, fibrinogen, and red cell deformability, but not temperature. DSS, defined as the minimum shear stress to disperse RBC aggregates under dynamic conditions, is dependent upon fibrinogen, red cell deformability, and temperature but not hematocrit. Owing to recent advances in measurement technology, these two parameters can be easily measured, and thus, their clinical significance in blood circulation can be verified.

  2. COPD - managing stress and your mood

    MedlinePlus

    ... with COPD have a greater risk for depression, stress, and anxiety. Being stressed or depressed can make ... your physical health. Learning how to deal with stress and anxiety and seeking care for depression can ...

  3. Coping with Stress during Infectious Disease Outbreaks

    MedlinePlus

    · Coping With Stress During Infectious Disease Outbreaks What You Should Know When you hear, read, or watch news about an outbreak ... you may feel anxious and show signs of stress. These signs of stress are normal, and may ...

  4. Being a preceptor is stressful!

    PubMed

    Yonge, Olive; Krahn, Harvey; Trojan, Lorraine; Reid, Doreen; Haase, Mary

    2002-01-01

    Results of a mail survey of 295 preceptors indicated preceptoring nursing students can be a stressful experience, with overwork identified as the main source of stress. Overwork resulted from unsuitability of students for the clinical area, lack of time, and insufficient feedback and guidance. The findings suggest that both students and preceptors require proper readiness assessment and preceptorship preparation. Preceptorship stress needs to be acknowledged; it can be addressed through workload adjustments and by providing feedback and support from nurse educators, peers, and managers. PMID:11840019

  5. Voice stress analysis and evaluation

    NASA Astrophysics Data System (ADS)

    Haddad, Darren M.; Ratley, Roy J.

    2001-02-01

    Voice Stress Analysis (VSA) systems are marketed as computer-based systems capable of measuring stress in a person's voice as an indicator of deception. They are advertised as being less expensive, easier to use, less invasive in use, and less constrained in their operation then polygraph technology. The National Institute of Justice have asked the Air Force Research Laboratory for assistance in evaluating voice stress analysis technology. Law enforcement officials have also been asking questions about this technology. If VSA technology proves to be effective, its value for military and law enforcement application is tremendous.

  6. Spectator stresses and CMB observables

    SciTech Connect

    Giovannini, Massimo

    2010-06-15

    The large-scale curvature perturbations induced by spectator anisotropic stresses are analyzed across the matter-radiation transition. It is assumed that the anisotropic stress is associated with a plasma component whose energy density is subdominant both today and prior to photon decoupling. The enforcement of the momentum constraint and the interplay with the neutrino anisotropic stress determine the regular initial conditions of the Einstein-Boltzmann hierarchy. The cosmic microwave background observables have shapes and phases which differ both from the ones of the conventional adiabatic mode as well as from their nonadiabatic counterparts.

  7. Acoustic/Magnetic Stress Sensor

    NASA Technical Reports Server (NTRS)

    Heyman, J. S.; Namkung, M.

    1986-01-01

    High-resolution sensor fast, portable, does not require permanent bonding to structure. Sensor measures nondestructively type (compressive or tensile) and magnitude of stresses and stress gradients present in class of materials. Includes precise high-resolution acoustic interferometer, sending acoustic transducer, receiving acoustic transducer, electromagnet coil and core, power supply, and magnetic-field-measuring device such as Hall probe. This measurement especially important for construction and applications where steel is widely used. Sensor useful especially for nondestructive evaluation of stress in steel members because of portability, rapid testing, and nonpermanent installation.

  8. [Post-traumatic stress disorder].

    PubMed

    Ponteva, Matti; Henriksson, Markus; Isoaho, Raimo; Laukkala, Tanja; Männikkö, Timo; Punamäki, Raija-Leena; Wahlbeck, Kristian

    2009-01-01

    Psychosocial support and careful monitoring are recommended for acute stress reaction (ASR) and acute stress disorder (ASD). If symptoms require, short focused cognitive-behavioural psychotherapy can be used for ASD. Medication is rarely necessary, but sleeping pills can be used for a short period. Trauma-focused psychotherapeutic interventions are first-line treatment for post-traumatic stress disorder. SSRI or SNRI antidepressant medication is also effective. There is less evidence on antipsychotic and antiepileptic medication. Psychotherapeutic interventions and medication can be, and often are, combined. Children, the elderly, and military and peacekeeping personnel need interventions that are tailored to their needs. PMID:19839195

  9. Stress-induced cervical lesions.

    PubMed

    Braem, M; Lambrechts, P; Vanherle, G

    1992-05-01

    The increasing occurrence of dental lesions at the cervical surfaces requires more knowledge of the causes of the process. Acidic and abrasive mechanisms have clearly been documented as causes but the stress theory by Lee and Eakle is still controversial. This report describes several incidences of possible stress-induced lesions according to the characteristics described by Lee and Eakle. The occurrences of subgingival lesions lend credence to the stress-induction theory by exclusion of other superimposing etiologic factors. With the current concepts, a perceptive approach to the treatment of cervical lesions can be executed. PMID:1527763

  10. Stress Fracture of the Sacrum.

    PubMed

    Hearn, Darren W; Humphrey, David W

    2015-11-01

    A physical therapist evaluated a 25-year-old male military trainee, who reported 1 week of left hip pain exacerbated by running and sitting cross-legged. At follow-up, the patient reported unchanged hip pain and new left knee pain. Due to potential for multifocal stress injuries outside the visual field of a single MRI, bone scan and single-photon emission computerized tomography were chosen as imaging modalities. Imaging revealed a nondisplaced lateral left-sided sacral stress fracture and left calcaneal stress fracture. J Orthop Sports Phys Ther 2015;45(11):965. doi:10.2519/jospt.2015.0411. PMID:27136290

  11. Stress optic coefficient and stress profile in optical fibers.

    PubMed

    Lagakos, N; Mohr, R; El-Bayoumi, O H

    1981-07-01

    The stress optic coefficient and stress profile in optical fibers have been determined photoelastically using a polariscope having good reproducibility and high sensitivity. The results of the work presented in this paper indicate that the photoelastic behavior may be different in fibers and in bulk glasses. The photoelastically determined clad compression in strengthened fibers was found to correlate well with the strengthening observed in these fibers using tensile tests. PMID:20332937

  12. Caracterisation de la cohesion de l'interface AMF/polymere dans une structure deformable adaptative

    NASA Astrophysics Data System (ADS)

    Fischer-Rousseau, Charles

    Les structures déformables adaptatives (SDA) sont appelées à jouer un rôle important en aéronautique entre autres. Les alliages à mémoire de forme (AMF) sont un des candidats les plus prometteurs. Beaucoup de travail reste toutefois à faire avant que ces structures rencontrent les exigences élevées reliées à leur intégration dans un contexte aéronautique. Des travaux de recherche ont montré que la résistance à la décohésion de l’interface AMF/polymère peut être un élément limitant dans la performance des SDA. Dans ce travail, l’effet sur la résistance à la décohésion de l’interface AMF/polymère de divers traitements de surface, géométries de fil et types de polymère est évalué. La géométrie du fil est modifiée par une combinaison spécifique de laminage à froid et de recuit postdéformation qui maintient les propriétés de mémoire de forme tout en permettant de réduire l’aire de la section transversale du fil. Le traitement thermomécanique le plus prometteur est proposé. Une nouvelle méthode d’évaluation de la résistance à la décohésion est développée. Plutôt que de tester les fils en arrachement et de mesurer la force maximale, les tests en contraction sont basés sur la capacité des fils d’AMF à se contracter s’ils ont été encastrés dans un état tiré et qu’ils sont chauffés par effet Joule. L’hypothèse qu’on pose est que ces tests sont une meilleure approximation des conditions rencontrées dans une SDA, où les fils se contractent plutôt qu’ils sont arrachés par une force externe à la structure. Bien qu’une décohésion partielle ait été observée pour tous les échantillons, l’aire de la surface où il y a décohésion tait plus grande pour les échantillons avec une pré-déformation plus grande. Le front de décohésion a semblé cesser de progresser après les cycles de chauffage initiaux lorsque la vitesse de chauffage était faible. Un modèle numérique simulant la

  13. Adding stress plot function to NASTRAN

    NASA Technical Reports Server (NTRS)

    Katoh, S.

    1978-01-01

    Stress plot function was developed and added to the NASTRAN level 15.5. Computed stress distribution can be displayed by this function, with vectors showing the principal stresses of the finite elements over the specified portions of the structure. NASTRAN is reviewed in the aspect of plotting capabilities. Stress tensor field is examined in preparation of stress display. Then the stress plot function as added to the NASTRAN is described. A sample plotout by this function is shown.

  14. Simultaneous Measurements of Neutron Environment at Mars from Orbit (Mars Odyssey HEND) and from the Surface (MSL DAN)

    NASA Astrophysics Data System (ADS)

    Martinez Sierra, L. M.; Jun, I.; Litvak, M. L.; Sanin, A. B.; Mitrofanov, I. G.

    2015-12-01

    Currently, the high energy neutron detector (HEND) onboard Mars Odyssey and the dynamic albedo of neutrons (DAN) instrument onboard the Mars Science Laboratory rover are simultaneously measuring the neutron environment from orbit and from the surface, respectively. Naturally-occurring neutrons at Mars are produced from the interactions of galactic cosmic rays (GCR) and solar energetic particles (SEP) with the Martian atmosphere and surface material. The neutron data from these simultaneous orbital and surface measurements are a good indicator for the state of general ambient radiation environments at Mars and can be also used as a means to infer how the ambient radiation is transported through the Martian atmosphere. Both HEND and DAN are healthy, and they provide the unique data sources valuable to study these phenomena for the period since the MSL landing in August 2012. Understanding of why there is correlation or no correlation between the two measurements will provide a key clue to understand the processes of GCR/SEP propagation through the Mars atmosphere and the interaction with the Mars surface materials. More detailed comparison between the two data sets and analysis of HEND/DAN data will be presented in the final presentation. Also, the long-term trend of the HEND/DAN data will be also compared with a general space weather condition. We used only publicly available HEND/DAN data in this study, e.g., open literature and/or planetary data system (PDS).

  15. Design of interpenetrated network MWCNT/poly(1,5-DAN) on interdigital electrode: toward NO2 gas sensing.

    PubMed

    Nguyen, Dzung Tuan; Nguyen, My Thanh; Ho, Giang Truong; Nguyen, Toan Ngoc; Reisberg, S; Piro, B; Pham, M C

    2013-10-15

    In this paper, poly(1,5-diaminonaphthalene) was interpenetrated into the network made of multiwalled carbon nanotubes (MWCNT) on platinum interdigital electrode (IDE) by electro-polymerization of 1,5-diaminonaphthalene (1,5-DAN). The electro-polymerization process of 1,5-DAN on MWCNT was controlled by scanning the cyclic voltage at 50 mV s(-1) scan rate between -0.1 V and +0.95 V vs. saturated calomel electrode (SCE). The results of voltammetric responses and Raman spectroscopy represented that the films MWCNT/poly(1,5-DAN) were successfully created by this polymerization process. The films MWCNT/poly(1,5-DAN) were investigated for gas-sensing to NO2 at low concentration level. The gas-sensing results showed that the response-recovery times were long and strongly affected by thickness of the film MWCNT/poly(1,5-DAN). Nevertheless, these films represented auspicious results for gas sensors operating at room temperature. PMID:24054652

  16. DanQ: a hybrid convolutional and recurrent deep neural network for quantifying the function of DNA sequences

    PubMed Central

    Quang, Daniel; Xie, Xiaohui

    2016-01-01

    Modeling the properties and functions of DNA sequences is an important, but challenging task in the broad field of genomics. This task is particularly difficult for non-coding DNA, the vast majority of which is still poorly understood in terms of function. A powerful predictive model for the function of non-coding DNA can have enormous benefit for both basic science and translational research because over 98% of the human genome is non-coding and 93% of disease-associated variants lie in these regions. To address this need, we propose DanQ, a novel hybrid convolutional and bi-directional long short-term memory recurrent neural network framework for predicting non-coding function de novo from sequence. In the DanQ model, the convolution layer captures regulatory motifs, while the recurrent layer captures long-term dependencies between the motifs in order to learn a regulatory ‘grammar’ to improve predictions. DanQ improves considerably upon other models across several metrics. For some regulatory markers, DanQ can achieve over a 50% relative improvement in the area under the precision-recall curve metric compared to related models. We have made the source code available at the github repository http://github.com/uci-cbcl/DanQ. PMID:27084946

  17. DanQ: a hybrid convolutional and recurrent deep neural network for quantifying the function of DNA sequences.

    PubMed

    Quang, Daniel; Xie, Xiaohui

    2016-06-20

    Modeling the properties and functions of DNA sequences is an important, but challenging task in the broad field of genomics. This task is particularly difficult for non-coding DNA, the vast majority of which is still poorly understood in terms of function. A powerful predictive model for the function of non-coding DNA can have enormous benefit for both basic science and translational research because over 98% of the human genome is non-coding and 93% of disease-associated variants lie in these regions. To address this need, we propose DanQ, a novel hybrid convolutional and bi-directional long short-term memory recurrent neural network framework for predicting non-coding function de novo from sequence. In the DanQ model, the convolution layer captures regulatory motifs, while the recurrent layer captures long-term dependencies between the motifs in order to learn a regulatory 'grammar' to improve predictions. DanQ improves considerably upon other models across several metrics. For some regulatory markers, DanQ can achieve over a 50% relative improvement in the area under the precision-recall curve metric compared to related models. We have made the source code available at the github repository http://github.com/uci-cbcl/DanQ. PMID:27084946

  18. Liposome adhesion generates traction stress

    NASA Astrophysics Data System (ADS)

    Murrell, Michael P.; Voituriez, Raphaël; Joanny, Jean-François; Nassoy, Pierre; Sykes, Cécile; Gardel, Margaret L.

    2014-02-01

    Mechanical forces generated by cells modulate global shape changes required for essential life processes, such as polarization, division and spreading. Although the contribution of the cytoskeleton to cellular force generation is widely recognized, the role of the membrane is considered to be restricted to passively transmitting forces. Therefore, the mechanisms by which the membrane can directly contribute to cell tension are overlooked and poorly understood. To address this, we directly measure the stresses generated during liposome adhesion. We find that liposome spreading generates large traction stresses on compliant substrates. These stresses can be understood as the equilibration of internal, hydrostatic pressures generated by the enhanced membrane tension built up during adhesion. These results underscore the role of membranes in the generation of mechanical stresses on cellular length scales and that the modulation of hydrostatic pressure due to membrane tension and adhesion can be channelled to perform mechanical work on the environment.

  19. Reduce stress while improving performance.

    PubMed

    Corbin, C

    1993-05-01

    In summary, employee empowerment is a necessary component of the corporate culture because it increases productivity and the rate of employee retention. It simultaneously diminished employee job stress and associated costs. PMID:10129656

  20. Post-Traumatic Stress Disorder

    MedlinePlus

    ... Physician September 01, 2000, http://www.aafp.org/afp/20000901/1035.html) Post-traumatic Stress Reactions Following ... Physician August 01, 1999, http://www.aafp.org/afp/990800ap/524.html) Written by familydoctor.org editorial ...

  1. Defenseive Structuring and Environmental Stress

    ERIC Educational Resources Information Center

    Siegel, Bernard J.

    1970-01-01

    This essay explores a kind of adaptation, referred to as defenseive structuring, that recurs with great regularity among groups that perceive themselves as exposed to environmental stress of long duration with which they cannot cope directly and aggressively." (Author)

  2. Oxidant stress in the vasculature.

    PubMed

    Maytin, M; Leopold, J; Loscalzo, J

    1999-09-01

    Vascular disease and vasomotor responses are largely influenced by oxidant stress. Superoxide is generated via the cellular oxidase systems, xanthine oxidase, and NADH/NADPH oxidases. Once formed, superoxides participate in a number of reactions, yielding various free radicals such as hydrogen peroxide, peroxynitrite, oxidized low-density lipoprotein, or hypochlorous acid. Numerous cellular antioxidant systems exist to defend against oxidant stress; glutathione and the enzymes superoxide dismutase and glutathione peroxidase are critical for maintaining the redox balance of the cell. However, the redox state is disrupted by certain vascular diseases. It appears that oxidant stress both promotes and is induced by diseases such as hypertension, atherosclerosis, and restenosis as well as by certain risk factors for coronary artery disease including hyperlipidemia, diabetes, and cigarette smoking. Once oxidant stress is invoked, characteristic pathophysiologic features ensue, namely adverse vessel reactivity, vascular smooth muscle cell proliferation, macrophage adhesion, platelet activation, and lipid peroxidation. PMID:11122705

  3. Interpersonal predictors of stress generation.

    PubMed

    Eberhart, Nicole K; Hammen, Constance L

    2009-05-01

    Hammen (1991) provided evidence for a stress generation process in which individuals with a history of depression contributed to the occurrence of stressors, especially interpersonal and conflict events. However, few studies have examined the factors contributing to stress generation. This study examines aspects of individuals' interpersonal style, operationalized as attachment, dependency, and reassurance seeking, as predictors of conflict stress generation within romantic relationships. These effects were examined both prospectively over a 4-week period and cross-sectionally using a 14-day daily diary in a sample of female college students. Overall, there was significant evidence that interpersonal style contributes to the occurrence of interpersonal stressors. Specifically, anxious attachment and reassurance seeking prospectively predicted romantic conflict stress over a 4-week period, and a variety of interpersonal behaviors were associated with romantic conflict stressors on a daily basis. These results are interpreted in relation to previous literature, and limitations and directions for future research are discussed. PMID:19171775

  4. [Heme metabolism and oxidative stress].

    PubMed

    Kaliman, P A; Barannik, T B

    2001-01-01

    The role of heme metabolism in oxidative stress development and defense reactions formation in mammals under different stress factors are discussed in the article. Heme metabolism is considered as the totality of synthesis, degradation, transport and exchange processes of exogenous heme and heme liberated from erythrocyte hemoglobin under erythrocyte aging and hemolysis. The literature data presented display normal heme metabolism including mammals heme-binding proteins and intracellular free heme pool and heme metabolism alterations under oxidative stress development. The main attention is focused to the prooxidant action of heme, the interaction of heme transport and lipid exchange, and to the heme metabolism key enzymes (delta-aminolevulinate synthase and heme oxygenase), serum heme-binding protein hemopexin and intracellular heme-binding proteins participating in metabolism adaptation under the action of factors, which cause oxidative stress. PMID:11599427

  5. Protecting Yourself from Heat Stress

    MedlinePlus

    ... Contact NIOSH NIOSH Fast Facts: Protecting Yourself from Heat Stress Language: English Español (Spanish) Kreyol Haitien (Haitian ... as heat stroke, heat exhaustion, or heat cramps. Heat Stroke A condition that occurs when the body ...

  6. Host Stress Drives Salmonella Recrudescence

    PubMed Central

    Verbrugghe, Elin; Dhaenens, Maarten; Leyman, Bregje; Boyen, Filip; Shearer, Neil; Van Parys, Alexander; Haesendonck, Roel; Bert, Wim; Favoreel, Herman; Deforce, Dieter; Thompson, Arthur; Haesebrouck, Freddy; Pasmans, Frank

    2016-01-01

    Host stress is well known to result in flare-ups of many bacterial, viral and parasitic infections. The mechanism by which host stress is exploited to increase pathogen loads, is poorly understood. Here we show that Salmonella enterica subspecies enterica serovar Typhimurium employs a dedicated mechanism, driven by the scsA gene, to respond to the host stress hormone cortisol. Through this mechanism, cortisol increases Salmonella proliferation inside macrophages, resulting in increased intestinal infection loads in DBA/2J mice. ScsA directs overall Salmonella virulence gene expression under conditions that mimic the intramacrophagic environment of Salmonella, and stimulates the host cytoskeletal alterations that are required for increased Salmonella proliferation inside cortisol exposed macrophages. We thus provide evidence that in a stressed host, the complex interplay between a pathogen and its host endocrine and innate immune system increases intestinal pathogen loads to facilitate pathogen dispersal. PMID:26857846

  7. Sleep in High Stress Occupations

    NASA Technical Reports Server (NTRS)

    Flynn-Evans, Erin

    2014-01-01

    High stress occupations are associated with sleep restriction, circadian misalignment and demanding workload. This presentation will provide an overview of sleep duration, circadian misalignment and fatigue countermeasures and performance outcomes during spaceflight and commercial aviation.

  8. Caregiver Stress and Elder Abuse

    MedlinePlus

    ... by care receivers to be particularly stressful, including aggression, combativeness, wandering and incontinence. Others report that they ... areas that need to be explored include how aggression by care receivers raises the risk of abuse, ...

  9. Chemical Educators Stress Industry Ties

    ERIC Educational Resources Information Center

    Worthy, Ward

    1975-01-01

    Describes various courses and programs designed to better prepare graduates to enter the chemical industry, including courses which stress the chemistry of industrial processes, and the economics of the chemical industry. (MLH)

  10. How Can I Manage Stress?

    MedlinePlus

    ... Can I Quit Smoking? How Can I Manage Stress? How Can I Make My Lifestyle Healthier? How Can I Monitor My Cholesterol, Blood Pressure and Weight? Popular Articles 1 Understanding Blood Pressure ...

  11. Magnetoacoustic stress measurements in steel

    NASA Technical Reports Server (NTRS)

    Namkung, M.; Utrata, D.; Allison, S. G.; Heyman, J. S.

    1985-01-01

    Uniaxial stress effects on the low-field magnetoacoustic interaction have been studied using bulk compressional waves and Rayleigh surface waves in numerous steel samples having various impurity concentrations (Namkung et al., 1984). The results invariably showed that the initial slope of acoustic natural velocity variations, with respect to net induced magnetization parallel to the stress axis, is positive under tension and negative under compression. The results of current measurements in railroad rail steel having about 0.68 wt percent carbon content are typical for medium range carbon steels. The low-field natural velocity slope in this particular type of steel, which is almost zero when unstressed, becomes steeper with increased magnitude of stress in both directions. Hence, the nondestructive determination of the sign of residual stress in railroad wheels and rails is possible using this technique. This paper discusses the basic physical mechanism underlying the experimental observations and presents the results obtained in railroad rail steel.

  12. Internal Stresses in Laminated Construction

    NASA Technical Reports Server (NTRS)

    Heim, A L; Knauss, A C; Seutter, Louis

    1923-01-01

    This report reviews the procedure employed in an investigation of the sources and influence of internal stresses in laminated construction, and discusses the influence of shrinkage and swelling stresses caused by atmospheric conditions upon the tensile strength across grain in laminated construction with special reference to airplane propellers. The investigation covered three sources of internal stress, namely, the combination of plain-sawed and quarter-sawed material in the same construction, the gluing together of laminations of different moisture contents, and the gluing together of laminations of different densities. Glued specimens and free specimens, made up under various manufacturing conditions, were subjected to various climatic changes inducing internal stresses and then were tested.

  13. [Psychogenic stress: theory, experiment, practice].

    PubMed

    Khananashvili, M M

    1998-01-01

    Experiments on animals (rodents, beasts, primates) and observation in man have ascertained that psychogenic stress is the most important defensive state of living organisms, which is constantly involved in order to maintain their interaction with external psychogenic factors. Three types of stress should be distinguished, these include normostress, hypostress, and hyperstress. Normostress has definite limits within which optimal responses, which are typical for an individual are realized. Hyperstress develops as a defensive response to extremely strong (extraordinary) stimuli. Hypostress can be observed in the retarded development of self-regulation mechanisms. All three types of stress are provided by a fundamental property of living organisms--the self-regulation mechanism, which realizes the keeping back of normostress constancy, or return of hyper- and hypostress to the normostress status. And only if an extreme deficit of self-regulation mechanisms takes place, hyper(hypo)stress could become a condition for the development of pathology. PMID:9771123

  14. Protecting Workers from Heat Stress

    MedlinePlus

    QUICK CARD TM Protecting Workers from Heat Stress Heat Illness Exposure to heat can cause illness and death. The most serious ... OSHA (6742) OSHA 3154 -06R 2014 QUICK CARD TM • Modify work schedules and arrange frequent rest periods ...

  15. Accelerated Stress-Corrosion Testing

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Test procedures for accelerated stress-corrosion testing of high-strength aluminum alloys faster and provide more quantitative information than traditional pass/fail tests. Method uses data from tests on specimen sets exposed to corrosive environment at several levels of applied static tensile stress for selected exposure times then subsequently tensile tested to failure. Method potentially applicable to other degrading phenomena (such as fatigue, corrosion fatigue, fretting, wear, and creep) that promote development and growth of cracklike flaws within material.

  16. Stress concentration investigations using NASTRAN

    NASA Technical Reports Server (NTRS)

    Gillcrist, M. C.; Parnell, L. A.

    1986-01-01

    Parametic investigations are performed using several two dimensional finite element formulations to determine their suitability for use in predicting extremum stresses in marine propellers. Comparisons are made of two NASTRAN elements (CTRIM6 and CTRAIA2) wherein elasticity properties have been modified to yield plane strain results. The accuracy of the elements is investigated by comparing finite element stress predictions with experimentally determined stresses in two classical cases: (1) tension in a flat plate with a circular hole; and (2) a filleted flat bar subjected to in-plane bending. The CTRIA2 element is found to provide good results. The displacement field from a three dimensional finite element model of a representative marine propeller is used as the boundary condition for the two dimensional plane strain investigations of stresses in the propeller blade and fillet. Stress predictions from the three dimensional analysis are compared with those from the two dimensional models. The validity of the plane strain modifications to the NASTRAN element is checked by comparing the modified CTRIA2 element stress predictions with those of the ABAQUS plane strain element, CPE4.

  17. Stress in Atlantic salmon: response to unpredictable chronic stress.

    PubMed

    Madaro, Angelico; Olsen, Rolf E; Kristiansen, Tore S; Ebbesson, Lars O E; Nilsen, Tom O; Flik, Gert; Gorissen, Marnix

    2015-08-01

    Combinations of stressors occur regularly throughout an animal's life, especially in agriculture and aquaculture settings. If an animal fails to acclimate to these stressors, stress becomes chronic, and a condition of allostatic overload arises with negative results for animal welfare. In the current study, we describe effects of exposing Atlantic salmon parr to an unpredictable chronic stressor (UCS) paradigm for 3 weeks. The paradigm involves exposure of fish to seven unpredictable stressors three times a day. At the end of the trial, experimental and control fish were challenged with yet another novel stressor and sampled before and 1 h after that challenge. Plasma cortisol decreased steadily over time in stressed fish, indicative of exhaustion of the endocrine stress axis. This was confirmed by a lower cortisol response to the novel stressor at the end of the stress period in chronically stressed fish compared with the control group. In the preoptic area (POA) and pituitary gland, chronic stress resulted in decreased gene expression of 11βhsd2, gr1 and gr2 in the POA and increased expression of those genes in the pituitary gland. POA crf expression and pituitary expression of pomcs and mr increased, whereas interrenal gene expression was unaffected. Exposure to the novel stressor had no effect on POA and interrenal gene expression. In the pituitary, crfr1, pomcs, 11βhsd2, grs and mr were down-regulated. In summary, our results provide a novel overview of the dynamic changes that occur at every level of the hypothalamic-pituitary gland-interrenal gland (HPI) axis as a result of chronic stress in Atlantic salmon. PMID:26056242

  18. Stress Matters: Effects of Anticipated Lexical Stress on Silent Reading

    PubMed Central

    Breen, Mara; Clifton, Charles

    2012-01-01

    This paper presents findings from two eye-tracking studies designed to investigate the role of metrical prosody in silent reading. In Experiment 1, participants read stress-alternating noun-verb or noun-adjective homographs (e.g. PREsent, preSENT) embedded in limericks, such that the lexical stress of the homograph, as determined by context, either matched or mismatched the metrical pattern of the limerick. The results demonstrated a reading cost when readers encountered a mismatch between the predicted and actual stress pattern of the word. Experiment 2 demonstrated a similar cost of a mismatch in stress patterns in a context where the metrical constraint was mediated by lexical category rather than by explicit meter. Both experiments demonstrated that readers are slower to read words when their stress pattern does not conform to expectations. The data from these two eye-tracking experiments provide some of the first on-line evidence that metrical information is part of the default representation of a word during silent reading. PMID:22707848

  19. Grossesse dans une corne rudimentaire: difficultés diagnostiques et prise en charge thérapeutique

    PubMed Central

    Mamouni, Nisrine; Ghazal, Nabil; Erraghay, Sanaa; Bouchikhi, Chahrazed; Banani, Abdelaziz

    2016-01-01

    La survenue d'une grossesse dans une corne utérine rudimentaire est une situation obstétricale extrêmement rare et potentiellement grave, menaçant le pronostic materno-fœtal. Les auteurs rapportent cinq observations de grossesse dans une corne utérine rudimentaire, à travers lesquelles, ils relatent les difficultés sur le plan diagnostique ainsi que la prise en charge thérapeutique de cette entité pathologique, soulignant l'intérêt de l’échographie endovaginale, de l'IRM pelvienne et de la cœlioscopie dans le diagnostic précoce de ce type de malformation uterine.

  20. Theory of plasticity based on a new invariant of stress tensor. Two-dimensional stress

    NASA Astrophysics Data System (ADS)

    Revuzhenko, A. F.; Mikenina, O. A.

    2015-10-01

    The authors introduce a new stress tensor invariant proportional to a squared intensity of shear stresses versus maximum shear stress. The invariant means a shear stress averaged over three fans-areas along three principal stresses of the stress tensor. The theory is based on the invariant and the associated flow rule. The article gives equations of generalized two-dimensional stress state and an analysis of their types. The authors solve an axisymmetrical problem on limit state around a hole.

  1. Diversity in Robustness of Lactococcus lactis Strains during Heat Stress, Oxidative Stress, and Spray Drying Stress

    PubMed Central

    Dijkstra, Annereinou R.; Setyawati, Meily C.; Bayjanov, Jumamurat R.; Alkema, Wynand; van Hijum, Sacha A. F. T.; Hugenholtz, Jeroen

    2014-01-01

    In this study we tested 39 Lactococcus lactis strains isolated from diverse habitats for their robustness under heat and oxidative stress, demonstrating high diversity in survival (up to 4 log units). Strains with an L. lactis subsp. lactis phenotype generally displayed more-robust phenotypes than strains with an L. lactis subsp. cremoris phenotype, whereas the habitat from which the strains had been isolated did not appear to influence stress survival. Comparison of the stress survival phenotypes with already available comparative genomic data sets revealed that the absence or presence of specific genes, including genes encoding a GntR family transcriptional regulator, a manganese ABC transporter permease, a cellobiose phosphotransferase system (PTS) component, the FtsY protein, and hypothetical proteins, was associated with heat or oxidative stress survival. Finally, 14 selected strains also displayed diversity in survival after spray drying, ranging from 20% survival for the most robust strains, which appears acceptable for industrial application, to 0.1% survival for the least-tolerant strains. The high and low levels of survival upon spray drying correlated clearly with the combined robustness under heat and oxidative stress. These results demonstrate the relevance of screening culture collections for robustness under heat and oxidative stress on top of the typical screening for acidifying and flavor-forming properties. PMID:24212574

  2. The stress pattern of Iceland

    NASA Astrophysics Data System (ADS)

    Ziegler, Moritz; Rajabi, Mojtaba; Heidbach, Oliver; Hersir, Gylfi Páll; Ágústsson, Kristján; Árnadóttir, Sigurveig; Zang, Arno

    2016-04-01

    Iceland is located on the Mid-Atlantic Ridge which is the plate boundary between the Eurasian and the North American plates. It is one of the few places on earth where an active spreading centre is located onshore but the stress pattern has not been extensively investigated so far. In this paper we present a comprehensive compilation of the orientation of maximum horizontal stress (SHmax). In particular we interpret borehole breakouts and drilling induced fractures from borehole image logs in 57 geothermal wells onshore Iceland. The borehole results are combined with other stress indicators including earthquake focal mechanism solutions, geological information and overcoring measurements resulting in a dataset with 495 data records for the SHmax orientation. The reliability of each indicator is assessed according to the quality criteria of the World Stress Map project. The majority of SHmax orientation data records in Iceland is derived from earthquake focal mechanism solutions (35%) and geological fault slip inversions (26%). 20% of the data are borehole related stress indicators. In addition minor shares of SHmax orientations are compiled, amongst others, from focal mechanism inversions and the alignment of fissure eruptions. The results show that the SHmax orientations derived from different depths and stress indicators are consistent with each other. The resulting pattern of the present-day stress in Iceland has four distinct subsets of SHmax orientations. The SHmax orientation is parallel to the rift axes in the vicinity of the active spreading regions. It changes from NE-SW in the South to approximately N-S in central Iceland and NNW-SSE in the North. In the Westfjords which is located far away from the ridge the regional SHmax rotates and is parallel to the plate motion.

  3. Performance, Stress, and Health: Overall Reaction.

    ERIC Educational Resources Information Center

    Landers, Daniel M.

    1994-01-01

    Reviews articles on stress and exercise. After defining stress, the paper analyzes competition as either eustress or distress, provides evidence for Berger's taxonomy of stress and exercise, examines Type A behavior, discusses multidimensional anxiety and stress management, describes the inverted-U hypothesis and task characteristics, and explains…

  4. The Contagion of Stress across Multiple Roles.

    ERIC Educational Resources Information Center

    Bolger, Niall; And Others

    1989-01-01

    Examined causal dynamics of stress contagion across work and home domains in married couples. Results revealed that husbands were more likely than wives to bring home stresses into workplace. Stress contagion from work to home was evident for both husbands and wives. Contagion of work stress into home appeared to set into motion process of dyadic…

  5. Learning Havens for Stressed Adult Learners

    ERIC Educational Resources Information Center

    Seay, Sandra E.

    2005-01-01

    Having stressful workdays is not the sole prerogative of adult students enrolled in educational leadership programs. According to a report released by the American Institute of Stress in 2002, 80% of adult workers felt stress in the workplace. From this it can be assumed that a certain amount of stress accompanies every adult who enters an evening…

  6. Stress Management Techniques for the 1990's.

    ERIC Educational Resources Information Center

    Patterson, Jeff

    An overview of stress management techniques is offered in this paper. Special focus is on the characteristics, causes, and effects of stress; potential sufferers; six reduction strategies; and stress and the principalship. A conclusion is that stress is real; although complete elimination is unlikely, it can be alleviated through effective…

  7. Stress in College Athletics: Causes, Consequences, Coping.

    ERIC Educational Resources Information Center

    Humphrey, James H.; Yow, Deborah A.; Bowden, William W.

    This book addresses the causes and consequences of stress in college sports and offers effective coping mechanisms to help individuals understand and control stressors and emotions in their environment. The chapters are: (1) "Understanding Stress"; (2) "Perceptions of Stress in College Athletics"; (3) "Stress among College Athletes"; (4) "Stress…

  8. Consequences of Stress for Public School Superintendents

    ERIC Educational Resources Information Center

    Carroll, Kathy J.

    2010-01-01

    Scope and Method of Study: This study is a quantitative study of Oklahoma Public School Superintendents. The data was collected by surveys using an online format. Data was analyzed to determine correlation and predictive values of the four specific stress factors: conflict mediating stress, boundary spanning stress, task based stress and role…

  9. Towards a Stress Free Education: International Perspective

    ERIC Educational Resources Information Center

    Sedere, Upali M.

    2010-01-01

    Stress is simply the body's response to changes that create taxing demands. When one cannot cope with it, these cause distresses. Stress is not always bad. The manageable stress motivates individuals to achieve what he/she wishes to achieve. When one can cope with stress it is called "eustress" which is good. Education in many countries cause…

  10. The ABCs of Managing Teacher Stress.

    ERIC Educational Resources Information Center

    Nagel, Liza; Brown, Sheri

    2003-01-01

    Describes stress management for teachers and presents strategies that teachers can use to lessen the impact of stress. Outlines the ABCs of stress: Acknowledge, Behavior Modification, and Communication. Notes that stress can motivate teachers to explore new instructional strategies, adopt innovative approaches to increasing student motivation, and…

  11. 46 CFR 154.421 - Allowable stress.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Allowable stress. 154.421 Section 154.421 Shipping COAST... § 154.421 Allowable stress. The allowable stress for the integral tank structure must meet the American Bureau of Shipping's allowable stress for the vessel's hull published in “Rules for Building and...

  12. Stress Assignment in Reading Italian Polysyllabic Pseudowords

    ERIC Educational Resources Information Center

    Sulpizio, Simone; Arduino, Lisa S.; Paizi, Despina; Burani, Cristina

    2013-01-01

    In 4 naming experiments we investigated how Italian readers assign stress to pseudowords. We assessed whether participants assign stress following distributional information such as stress neighborhood (the proportion and number of existent words sharing orthographic ending and stress pattern) and whether such distributional information affects…

  13. 46 CFR 154.421 - Allowable stress.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Allowable stress. 154.421 Section 154.421 Shipping COAST... § 154.421 Allowable stress. The allowable stress for the integral tank structure must meet the American Bureau of Shipping's allowable stress for the vessel's hull published in “Rules for Building and...

  14. 46 CFR 154.421 - Allowable stress.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Allowable stress. 154.421 Section 154.421 Shipping COAST... § 154.421 Allowable stress. The allowable stress for the integral tank structure must meet the American Bureau of Shipping's allowable stress for the vessel's hull published in “Rules for Building and...

  15. 46 CFR 154.421 - Allowable stress.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Allowable stress. 154.421 Section 154.421 Shipping COAST... § 154.421 Allowable stress. The allowable stress for the integral tank structure must meet the American Bureau of Shipping's allowable stress for the vessel's hull published in “Rules for Building and...

  16. Priming Lexical Stress in Reading Italian Aloud

    ERIC Educational Resources Information Center

    Sulpizio, Simone; Job, Remo; Burani, Cristina

    2012-01-01

    Two experiments using a lexical priming paradigm investigated how stress information is processed in reading Italian words. In both experiments, prime and target words either shared the stress pattern or they had different stress patterns. We expected that lexical activation of the prime would favour the assignment of congruent stress to the…

  17. 46 CFR 154.421 - Allowable stress.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Allowable stress. 154.421 Section 154.421 Shipping COAST... § 154.421 Allowable stress. The allowable stress for the integral tank structure must meet the American Bureau of Shipping's allowable stress for the vessel's hull published in “Rules for Building and...

  18. 46 CFR 154.440 - Allowable stress.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Allowable stress. 154.440 Section 154.440 Shipping COAST... Tank Type A § 154.440 Allowable stress. (a) The allowable stresses for an independent tank type A must... Commandant (CG-522). (b) A greater allowable stress than required in paragraph (a)(1) of this section may...

  19. Work Stress Inventory, Scale 2: Job Risk.

    ERIC Educational Resources Information Center

    Barone, David F.; And Others

    Although the effects of occupational or work stress have received considerable attention in recent years, few studies have attempted to systematically measure the construct. Prior to this study, Scale 1 of the Work Stress Inventory was developed to measure three indices: (1) appraised stress; (2) frequency of stressful situations; and (3)…

  20. Fluctuations quantiques et instabilites structurales dans les conducteurs a basse dimensionalite

    NASA Astrophysics Data System (ADS)

    Dikande, Alain Moise

    Un engouement particulier s'est manifeste ces dernieres annees pour les systemes electroniques fortement correles, ce en rapport avec l'immense richesse de leurs proprietes physiques. En general, ces proprietes sont induites par la presence d'interactions entre electrons qui, combinees a la structure du reseau moleculaire, donnent parfois lieu a une tres grande variete de phases electroniques et structurales ayant des incidences directes sur les phenomenes de transport dans ces materiaux. Les systemes electroniques couples a un reseau moleculaire et designes systemes electron-phonon font partie de cette classe de materiaux qui ont recemment capte l'attention, en raison notamment de la competition entre plusieurs echelles d'energie dans un environnement caracterise par une forte anisotropie cristalline et une dynamique moleculaire assez importante. En effet, en plus des proprietes electroniques et structurales particulieres la dimensionalite de ces systemes contribue egalement a leur richesse. Ainsi, une tres forte anisotropie structurale peut rehausser de facon considerable l'importance des interactions entre electrons et entre molecules constituant le reseau au point ou la physique du systeme soit regie par de tres fortes fluctuations. Ce dernier contexte est devenu un domaine a part de la physique des systemes fortement correles, a savoir celui des les phenomenes critiques quantiques . Parmi les systemes electron-phonon, on retrouve les composes inorganique KCP et organique TTF-TCNQ decouverts durant les annees 70, et explores en profondeur a cause de leur tendance vers une instabilite du type onde de densite de charge a basse temperature. Ces composes, en general designes systemes de Peierls en reference a l'instabilite de leurs structures electroniques regie par le reseau moleculaire, ont recemment connu un regain d'interet a la lumiere des nouveaux developpements dans les techniques de caracterisation des structures electroniques ainsi que sur le plan de

  1. Flight Investigation of the Performance of a Two-stage Solid-propellant Nike-deacon (DAN) Meteorological Sounding Rocket

    NASA Technical Reports Server (NTRS)

    Heitkotter, Robert H

    1956-01-01

    A flight investigation of two Nike-Deacon (DAN) two-stage solid-propellant rocket vehicles indicated satisfactory performance may be expected from the DAN meteorological sounding rocket. Peak altitudes of 356,000 and 350,000 feet, respectively, were recorded for the two flight tests when both vehicles were launched from sea level at an elevation angle of 75 degrees. Performance calculations based on flight-test results show that altitudes between 358,000 feet and 487,000 feet may be attained with payloads varying between 60 pounds and 10 pounds.

  2. The Stress Pattern of Iceland

    NASA Astrophysics Data System (ADS)

    Ziegler, Moritz; Rajabi, Mojtaba; Heidbach, Oliver; Páll Hersir, Gylfi; Ágústsson, Kristján; Árnadóttir, Sigurveig; Zang, Arno

    2016-04-01

    Iceland is one of the few places on earth where an active spreading can be observed onshore, yet the contemporary crustal stress state has not been investigated intesively. We compiled the first comprehensive stress map of Iceland from different stress indicators and analysed data from 57 Icelandic geothermal boreholes. In total we interpreted appox. 37 km of acoustic image logs for stress indicators, i.e. borehole breakouts and drilling induced tensile fractures. Furthermore we revised the 38 data records for Iceland from the World Stress Map 2008 and conducted an extensive literature research to compile all available focal mechanism solutions and geological stress indicators. The new stress compilation consists of 495 data records for the orientation of the maximum horizontal stress (SHmax) in and around Iceland with 318 data records of A-D qualities according to the World Stress Map ranking scheme. Most of the data records are derived from focal mechanism solutions (35%) and geological fault inversions (26%). Borehole related indicators (breakouts, drilling induced fractures, hydro-fractures) have a share of 20%. Minor contributions to the dataset are provided by the alignment of volcanic vents and fissures and overcoring measurements. The mean orientation of SHmax is 17° ± 39° for all A-D quality data. A closer look at subregions reveals four different provinces with fairly consistent SHmax orientation. They are in the Capital area and Southern Lowlands (mean SHmax = 38° ± 29°), the eastern Highlands and Eastfjords (mean SHmax = 8° ± 25°), the Tjörnes Fracture Zone and Akureyri (mean SHmax = 151° ± 21°), and the Westfjords (mean SHmax = 137° ± 17°). This distribution of SHmax orientations is in agreement with the prevailing tectonic structure. At the spreading ridges Reykjanes and Kolbeinsey in the South and North respectively an orientation of SHmax parallel to the plate boundary is observed. The same is observed in the Northern and Eastern

  3. Stress exposure and stress generation in children of depressed mothers.

    PubMed

    Adrian, C; Hammen, C

    1993-04-01

    Two hypotheses were tested: (a) One mechanism contributing to the high rate of disorder in children of women with affective disorders is elevated exposure to stressful events and conditions and (b) the children of depressed women, particularly women with unipolar depression, contribute to event occurrence because of increased interpersonal conflict. Life stress interview assessments were made at 6-month intervals for 3 years on 53 children of unipolar, bipolar, medically ill, and normal women. Both hypotheses were confirmed. Transactional models of risk and further studies of the interpersonal functioning of children at risk for depression are needed. PMID:8473589

  4. [Endoplasmic reticulum stress response in osteogenesis].

    PubMed

    Saito, Atsushi; Imaizumi, Kazunori

    2013-11-01

    Various cellular conditions such as synthesis of abundant proteins, expressions of mutant proteins and oxidative stress lead to accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER) lumen. This type of stress is called ER stress. The excessive ER stress causes cellular damages followed by apoptosis. When ER stress occurs, cells are activated ER stress response (unfolded protein response) to avoid cellular damages. Recently, it has been clear that ER stress response plays crucial roles not only in cell survival after ER stress but also in regulating various cellular functions and tissue formations. In particular, ER stress and ER stress response regulate protein quality control, secretory protein production, and smooth secretion of proteins in the cells such as osteoblasts which synthesize and secrete enormous matrix proteins. PMID:24162596

  5. Interpretation des donnees de flux de chaleur et de gravite dans le bouclier Canadien

    NASA Astrophysics Data System (ADS)

    Cheng, Li Zhen

    2000-10-01

    Le champ geothermique du Bouclier Canadien est caracterise par un flux moyen de 41 mW·m-2, qui suggere une production de chaleur moyenne dans la croute comprise entre 0.7 et 0.8 muW·m-3. Le flux de chaleur relativement faible favorise la stabilite du bouclier et lui a permis de resister a la deformation tectonique. Les variations du flux de chaleur a la surface sont dominees par la composition de la croute. Un flux eleve implique generalement une composition felsique et il est d'autant plus faible que la croute devient plus mafique. La production de chaleur en surface n'est pas representative de la production moyenne de la croute. Le flux de chaleur dans le Boucher Canadien ne depend donc pas de la production de chaleur en surface, mais depend de la composition principale de la croute. L'interpretation combinee des donnees geophysiques nous permet de determiner les variations de composition d'echelle crustale a partir desquelles il est possible d'etablir la structure de la croute. L'etude detaillee de l'Orogene de Trans-Hudson et de la Sous-province d'Abitibi a montre que le flux de chaleur, la gravite et la sismique lorsqu'elles sont combinees fournissent des contraintes efficaces pour determiner l'architecture crustale. En general, la croute est trop resistante pour se deformer par fluage, excepte tres localement. Le mode de deformation de la lithosphere continentale depend de la composition et du gradient geothermique. Nous montrons que la lithosphere du Bouclier Canadien demeure principalement fragile jusqu'a une profondeur de plus de 150 km. Une deformation ductile pourrait cependant etre possible localement a la base de la, croute, comme dans la ceinture de Thompson par exemple. Si l'on admet que la lithosphere peut resister a des contraintes allant jusqu'a 20 MPa (taux de deformation 3˙ < 10-15 s-1), l'epaisseur de la lithosphere est de l'ordre de 300 km pour la ceinture de Thompson et est superieure a 300 km pour la sous-province d'Abitibi. La resistance

  6. Altération des sulfures des granulats dans les chaussées

    NASA Astrophysics Data System (ADS)

    Jigorel, A.; Jauberthie, R.

    2002-07-01

    Sulfides present in hornsfeld aggregates, used in light pavanent construction in contact with humid air alter rapidly. Crystallisation of sulfates at the interface of bitumastic material and sub-base creates serious problems (intumescence and crazing) that can lead to a total reconstruction of the project (roads, sidewalks, sports areas, etc). The sulfides in the aggregates and the sulfates produced due to alteration are studied by SEM and XRD. The results show that the intensity of this phenomenon is linked to the nature and the crystallinity of the sulfides. The evolution of the sulfates formed during this alteration process is slow and complex. In new pavements (3 years) the sulfates have a pulverised appearance and consist mostly of epsomite, associated with pickeringite and halotrichite. In older pavements (20 years) the sulfates form a fibrous concretion consisting of pickeringite and small quantities of halotrichite. Les sulfures présents dans les granulats élaborés à partir de cornéen nes s'altèrent rapidement dans les chaussées légères en présence d'air humide. La cristallisation des sulfates à l'interface enrobé-couche de fondation crée des désordres si importants (intumescences, faiençage) qu'il est bien souvent nécessaire d'assurer la réfection totale des ouvrages (routes, trottoirs, plateaux sportifs...). Les sulfures des granulats et les sulfates issus du processus d'altération ont été étudiés par diffractométrie X et examen su Microscope Electronique à Balayage équipé de microanalyse X. Les résultats montrent que !intensité des désordres est liée à la nature et à la cristallinité des sulfures. Les sulfates formés évoluent su cours du processus d'altération qui est long et complexe. Dans les chaussées récentes (3 ans) ils ont un aspect pulvérulent et sont constitués d'epsomite dominante associée à de la pickeringite et à de l'halotrichite. Dans les chaussées plus anciennes (20 ans) ils forment des concr

  7. Interactions électron-électron dans les fils mésoscopiques

    NASA Astrophysics Data System (ADS)

    Pierre, F.

    Electron-electron interactions in mesoscopic wires In metallic thin films, the screening of Coulomb interactions is less efficient than in bulk metals because of electron elastic scattering from film boundaries, lattice defects, and impurities. As a consequence, at sub-kelvin temperatures, electron-electron interactions are expected to be the dominant inelastic process undergone by electrons, which determines energy exchange and limits the electronic phase coherence. We present in this book three experiments that probe inelastic collisions experienced by electrons at low temperature, in order to find out their mechanism. In the first part, we present a series of measurements of the energy distribution function of electrons in copper, gold and silver wires driven in a steady-state, out of equilibrium situation. These experiments reveal the rate at which electrons exchange energy. These results are compared in the second part with the temperature dependence of the phase coherence time of electrons tau_{φ}, which is deduced from the magnetoresistance of long wires. The phase coherence of electrons is limited by all inelastic collisions, independently of the energy exchanged. Different mechanisms to account for the energy exchange rate and dephasing times are proposed and compared with experiments. In the third part, we present measurements of the conductance of a long tunnel junction between an aluminum wire and a ground plane. The dip in the conductance at zero voltage is expected from the theory of electron-electron interactions. To compare measurements and theoretical predictions, we rephrase the microscopic theory of electron-electron interactions in terms of an electromagnetic impedance, as is done for the phenomenological theory of Coulomb blockade. Dans les couches minces métalliques, l'écrantage des interactions coulombiennes entre électrons est moins efficace que dans les métaux massifs en raison des chocs élastiques que subissent les électrons sur les

  8. [Occupational stress and myocardial infarction].

    PubMed

    Consoli, Silla M

    2015-01-01

    Besides the best-known role of depressed mood, occupational stress deserves to be taken as a coronary risk factor. There are two basic models to define occupational stress: Karasek's model (high job psychological demands associated with low decision latitude, or even low social support at work) and Siegrist's model (imbalance between efforts and rewards received). The combination of the two models better reflects the coronary risk than each model alone. Occupational stress appears both as a risk factor and a prognostic factor after the occurrence of myocardial infarction. The relevance of the models is best in men or in younger age subjects. In women, role conflicts (occupational/domestic), the existence of excessive "intrinsic" efforts (job over investment) and association with marital stress provide more specific information. Burnout, particularly among health professionals, and bullying at work are also linked to cardiovascular risk. Occupational stress is a collective indicator of health at work, valuable to the employer. At an individual level, it can lead to therapeutic preventive approaches. PMID:26150284

  9. Stress in Family Practice Residents

    PubMed Central

    Rudner, Howard L.

    1986-01-01

    Sources and levels of stress, as well as coping mechanisms, perceived by residents in both years of a two-year family practice residency program in Toronto are described. In addition, differences between first- and second-year residents, and between women and men residents, regardless of year, are examined. Results of the survey indicate that the levels of stress are relatively high throughout the two years of residency training. The three most stressful aspects of being a resident are time pressures, fatigue, and lack of self-confidence. Female residents appear to report a higher level of stress than males, especially in trying to combine a personal and a professional life. Specific coping mechanisms include talking to others, adjusting attitudes and feelings, or strategic use of time. Recommendations aimed at helping family medicine residency programs deal with the problem of stress in residents are suggested. A current major province-wide research study including all interns and residents in Ontario is described. PMID:21267263

  10. Proline Mechanisms of Stress Survival

    PubMed Central

    Liang, Xinwen; Zhang, Lu; Natarajan, Sathish Kumar

    2013-01-01

    Abstract Significance: The imino acid proline is utilized by different organisms to offset cellular imbalances caused by environmental stress. The wide use in nature of proline as a stress adaptor molecule indicates that proline has a fundamental biological role in stress response. Understanding the mechanisms by which proline enhances abiotic/biotic stress response will facilitate agricultural crop research and improve human health. Recent Advances: It is now recognized that proline metabolism propels cellular signaling processes that promote cellular apoptosis or survival. Studies have shown that proline metabolism influences signaling pathways by increasing reactive oxygen species (ROS) formation in the mitochondria via the electron transport chain. Enhanced ROS production due to proline metabolism has been implicated in the hypersensitive response in plants, lifespan extension in worms, and apoptosis, tumor suppression, and cell survival in animals. Critical Issues: The ability of proline to influence disparate cellular outcomes may be governed by ROS levels generated in the mitochondria. Defining the threshold at which proline metabolic enzyme expression switches from inducing survival pathways to cellular apoptosis would provide molecular insights into cellular redox regulation by proline. Are ROS the only mediators of proline metabolic signaling or are other factors involved? Future Directions: New evidence suggests that proline biosynthesis enzymes interact with redox proteins such as thioredoxin. An important future pursuit will be to identify other interacting partners of proline metabolic enzymes to uncover novel regulatory and signaling networks of cellular stress response. Antioxid. Redox Signal. 19, 998–1011. PMID:23581681

  11. Auxin response under osmotic stress.

    PubMed

    Naser, Victoria; Shani, Eilon

    2016-08-01

    The phytohormone auxin (indole-3-acetic acid, IAA) is a small organic molecule that coordinates many of the key processes in plant development and adaptive growth. Plants regulate the auxin response pathways at multiple levels including biosynthesis, metabolism, transport and perception. One of the most striking aspects of plant plasticity is the modulation of development in response to changing growth environments. In this review, we explore recent findings correlating auxin response-dependent growth and development with osmotic stresses. Studies of water deficit, dehydration, salt, and other osmotic stresses point towards direct and indirect molecular perturbations in the auxin pathway. Osmotic stress stimuli modulate auxin responses by affecting auxin biosynthesis (YUC, TAA1), transport (PIN), perception (TIR/AFB, Aux/IAA), and inactivation/conjugation (GH3, miR167, IAR3) to coordinate growth and patterning. In turn, stress-modulated auxin gradients drive physiological and developmental mechanisms such as stomata aperture, aquaporin and lateral root positioning. We conclude by arguing that auxin-mediated growth inhibition under abiotic stress conditions is one of the developmental and physiological strategies to acclimate to the changing environment. PMID:27052306

  12. The bacterial translation stress response

    PubMed Central

    Starosta, Agata L.; Lassak, Jürgen; Jung, Kirsten; Wilson, Daniel N.

    2014-01-01

    Throughout their life, bacteria need to sense and respond to environmental stress. Thus, such stress responses can require dramatic cellular reprogramming, both at the transcriptional as well as the translational level. This review focuses on the protein factors that interact with the bacterial translational apparatus in order to respond to and cope with different types of environmental stress. For example, the stringent factor RelA interacts with the ribosome to generate ppGpp under nutrient deprivation, whereas a variety of factors have been identified that bind to the ribosome under unfavorable growth conditions to shut-down (RelE, pY, RMF, HPF and EttA) or re-program (MazF, EF4 and BipA) translation. Additional factors have been identified that rescue ribosomes stalled due to stress-induced mRNA truncation (tmRNA, ArfA, ArfB), translation of unfavorable protein sequences (EF-P), heat shock induced subunit dissociation (Hsp15) or antibiotic inhibition (TetM, FusB). Understanding the mechanism of how the bacterial cell responds to stress will not only provide fundamental insight into translation regulation, but will also be an important step to identifying new targets for the development of novel antimicrobial agents. PMID:25135187

  13. Fiber networks amplify active stress

    NASA Astrophysics Data System (ADS)

    Lenz, Martin; Ronceray, Pierre; Broedersz, Chase

    Large-scale force generation is essential for biological functions such as cell motility, embryonic development, and muscle contraction. In these processes, forces generated at the molecular level by motor proteins are transmitted by disordered fiber networks, resulting in large-scale active stresses. While fiber networks are well characterized macroscopically, this stress generation by microscopic active units is not well understood. I will present a comprehensive theoretical study of force transmission in these networks. I will show that the linear, small-force response of the networks is remarkably simple, as the macroscopic active stress depends only on the geometry of the force-exerting unit. In contrast, as non-linear buckling occurs around these units, local active forces are rectified towards isotropic contraction and strongly amplified. This stress amplification is reinforced by the networks' disordered nature, but saturates for high densities of active units. I will show that our predictions are quantitatively consistent with experiments on reconstituted tissues and actomyosin networks, and that they shed light on the role of the network microstructure in shaping active stresses in cells and tissue.

  14. Oxidative Stress and Insulin Resistance

    PubMed Central

    Park, Kyong; Gross, Myron; Lee, Duk-Hee; Holvoet, Paul; Himes, John H.; Shikany, James M.; Jacobs, David R.

    2009-01-01

    OBJECTIVE Although cumulative evidence suggests that increased oxidative stress may lead to insulin resistance in vivo or in vitro, community-based studies are scarce. This study examined the longitudinal relationships of oxidative stress biomarkers with the development of insulin resistance and whether these relationships were independent of obesity in nondiabetic young adults. RESEARCH DESIGN AND METHODS Biomarkers of oxidative stress (F2-isoprostanes [F2Isop] and oxidized LDL [oxLDL]), insulin resistance (the homeostasis model assessment of insulin resistance [HOMA-IR]), and various fatness measures (BMI, waist circumference, and estimated percent fat) were obtained in a population-based observational study (Coronary Artery Risk Development in Young Adults) and its ancillary study (Young Adult Longitudinal Trends in Antioxidants) during 2000–2006. RESULTS There were substantial increases in estimated mean HOMA-IR over time. OxLDL and F2Isop showed little association with each other. Mean evolving HOMA-IR increased with increasing levels of oxidative stress markers (P < 0.001 for oxLDL and P = 0.06 for F2Isop), measured in 2000–2001. After additional adjustment for adiposity, a positive association between oxLDL and HOMA-IR was strongly evident, whereas the association between F2Isop and HOMA-IR was not. CONCLUSIONS We observed positive associations between each of two oxidative stress markers and insulin resistance. The association with oxidized LDL was independent of obesity, but that with F2Isop was not. PMID:19389821

  15. The occupational stress of judges.

    PubMed

    Rogers, J M; Freeman, S J; LeSage, P

    1991-06-01

    This paper reports the results of what is believed to be the first systematic survey of the Canadian judiciary about work-related stress. County and District Court judges from four provinces who were attending an educational event on two successive years (N = 104) reported in writing, anonymously, their perceptions of the most stressful aspects of being a judge. A similar survey of their spouses (N = 48) added another perspective to the findings. The overwhelming majority of respondents reported aspects of the work itself (for example, sentencing, child custody cases, judgements, decision-making, and jury trials) as being their primary source of occupational stress. This is not in keeping with the results of most studies, which find that workers view job factors such as role conflict, employer/employee relationships, and career decisions as being more stressful than the actual work they perform. Qualitative material from individual and group interviews suggests that additional preparation and training for the bench and mechanisms for reducing isolation and improving communication might alleviate the stress experienced by judges, while helping them to cope more effectively with their increasingly complex and difficult roles. PMID:1884331

  16. Occupational stress in psychiatric nursing.

    PubMed

    Sullivan, P J

    1993-04-01

    Psychiatric nursing is invariably assumed to be a stressful area of nursing practice. Empirical evidence to support this proposition is limited, however, due to the lack of research in this field. The purpose of this project was to examine occupational stress in a specified area of psychiatric nursing. The research was exploratory and therefore the concern was discovery and description rather than the testing of clear hypotheses and the development of causal relationships. The study has four main objectives. First, to describe the various stressors present in the work of the psychiatric nurse in the acute admission wards of two district health authorities. Secondly, to measure the effects of stress using a recognized and well-validated instrument for recording levels of burnout. Thirdly, through the use of a particular theoretical framework to identify the types of coping strategy used by the participants in the study. Fourthly, to note any clear associations between the stressors, the effects of stress and the ways of coping identified in the study. The conceptual basis for the project was Lazarus's cognitive theory of stress and coping and Maslach's model of burnout. PMID:8496507

  17. The history of stress hyperglycaemia.

    PubMed

    Balasanthiran, A; Shotliff, K

    2015-01-01

    Stress hyperglycaemia, is a common phenomenon, frequently associated with adverse outcomes in a number of prevalent conditions including myocardial infarction and stroke. Knowledge on stress hyperglycaemia evolved in tandem with knowledge relating to homeostasis, stress and disease and involved some of the world's most eminent thinkers. Despite this, it still remains under-recognised. This paper illustrates significant points in the history of stress hyperglycaemia, from antiquity through to the present day, as well as the challenges faced in translating research into clinical benefit for patients. Profiles of significant protagonists including Claude Bernard, Walter Cannon and Hans Seyle are presented, as well their roles in the emergence of modern-day terminology and pathophysiological models. Major themes such as 'fight or flight' and homeostasis are central to this discussion. Closer to the present day, the role of stress hyperglycaemia in a number of common medical conditions is explored in more detail. Contention around evidence for treatment and the future risk of diabetes mellitus are also discussed. PMID:26517107

  18. Stress corrosion susceptibility of stress-coined fastener holes in aircraft structures

    NASA Technical Reports Server (NTRS)

    Carter, A. E.; Hanagud, S.

    1975-01-01

    The cold working process of stress coining is used to provide fatigue improvement of fastener holes in aircraft structures. The cold working produces a radial flow of the metal. The residual stresses resulting from stress coining provide protection against fatigue damage by opposing the applied tensile stresses in service at the edge of the fastener hole. However, it is shown in this paper that in addition to the compressive stresses surrounding the stress coined hole, there are tensile stresses that result from the coining operation and that these residual tensile stresses can have a deleterious effect on the stress corrosion susceptibility of the postcoined structure.

  19. Stress Regularity or Consistency? Reading Aloud Italian Polysyllables with Different Stress Patterns

    ERIC Educational Resources Information Center

    Burani, Cristina; Arduino, Lisa S.

    2004-01-01

    Stress assignment to three- and four-syllable Italian words is not predictable by rule, but needs lexical look-up. The present study investigated whether stress assignment to low-frequency Italian words is determined by stress regularity, or by the number of words sharing the final phonological segment and the stress pattern (stress neighborhood…

  20. Stress and Schooling: A Search for Stress Profiles of Adolescent Students.

    ERIC Educational Resources Information Center

    Thomas, Elwyn

    This study examined how a sample of pre-university Singaporean adolescents (N=212) with an average age of 17 years 5 months attending a variety of junior colleges perceived and managed different sources of stress. Measures of stress included Behavior Profile, Life Events, School Stress Factors, Home-School Stress Conditions and Stress Symptoms.…

  1. Stressing Academia? Stress-as-Offence-to-Self at Danish Universities

    ERIC Educational Resources Information Center

    Opstrup, Niels; Pihl-Thingvad, Signe

    2016-01-01

    Academic work has traditionally been seen as relatively stress free. However, a growing number of studies have reported increases in occupational stress experienced by university researchers. In order to explain stress among this group, we build on a new perspective in occupational stress research: the so-called stress-as-offence-to-self…

  2. Oxidative stress and alopecia areata

    PubMed Central

    Prie, BE; Voiculescu, VM; Ionescu-Bozdog, OB; Petrutescu, B; Iosif, L; Gaman, LE; Clatici, VG; Stoian, I; Giurcaneanu, C

    2015-01-01

    Alopecia areata (AA) is an inflammatory and autoimmune disease presenting with non-scarring hair loss. The aethiopathogenesis of alopecia areata is unclear and many factors including autoimmunity, genetic predisposition, emotional and environmental stress are thought to play important roles in its development. Antioxidant/ oxidant balance perturbation is a common feature in autoimmune, emotional and environmental stress. Therefore, our paper discusses the implications of oxidative stress in alopecia areata. Abbreviations: AA = alopecia areata, ROS = reactive oxygen species, H2O2 = hydrogen peroxide, TBARS = thiobarbituric acid rective substances, MDA = malondialdehyde, TBARS = thiobarbituric acid-reactive substances, SOD = superoxide dismutase, CAT = catalase, GSH-Px = glutathione peroxidase, PON1 = paraoxonase 1, HO-1 = hemoxigenase 1, TrxR = thioredoxin reductase, GSH = glutathione PMID:26361510

  3. Oxidative stress in Alzheimer disease

    PubMed Central

    Durany, Nuria

    2009-01-01

    Alzheimer disease (AD) is a progressive dementia affecting a large proportion of the aging population. The histopathological changes in AD include neuronal cell death, formation of amyloid plaques and neurofibrillary tangles. There is also evidence that brain tissue in patients with AD is exposed to oxidative stress (e.g., protein oxidation, lipid oxidation, DNA oxidation and glycoxidation) during the course of the disease. Advanced glycation endproducts (AGEs) are present in amyloid plaques in AD, and its extracellular accumulation may be caused by an accelerated oxidation of glycated proteins. AGEs participate in neuronal death causing direct (chemical) and indirect (cellular) free radical production and consequently increase oxidative stress. The development of drugs for the treatment of AD that breaks the vicious cycles of oxidative stress and neurodegeneration offer new opportunities. These approaches include AGE-inhibitors, antioxidants and anti-inflammatory substances, which prevent free radical production. PMID:19372765

  4. Thermal stresses in composite tubes

    NASA Technical Reports Server (NTRS)

    Hyer, M. W.

    1986-01-01

    This paper summarizes work to determine the thermally-induced stresses and deformations in specially-constructed angle-ply composite tubes subjected to a uniform temperature change relative to their stress-free cure state. The tubes are designed for application to space structures and have high axial stiffness. Four angle-ply designs are examined in an effort to determine which design might have the most favorable thermally-induced response. A planar elasticity solution is used, the solution being valid away from the ends of the tube. Of the four designs considered, none has any particular advantage as far as stress levels are concerned. However, despite the fact that the tube wall is a balanced laminate, one design exhibits a significant amount of thermally-induced twist.

  5. Stresses of pipelines during earthquakes

    SciTech Connect

    Kiyomiya, O.

    1983-05-01

    Construction of submarine pipelines plays an important role in offshore development. Japan is famous for earthquake country. It is very important to estimate the earthquake proof of the submarine pipelines. An oil leakage causes the contamination of ocean if the submarine pipelines are damaged by earthquakes. Pipe stresses during earthquakes are closely related to the relative displacement of the ground. Field observation has been carried out to know the ground deformation. Steel pipe is assumed to be buried along the observation line and pipe stresses are calculated from the ground deformation obtained by the field observation. The stresses calculated by seismic deformation method that has been used for earthquake resistant design in Japan and by dynamic response analysis are compared with those from the observation.

  6. NEDDylation promotes stress granule assembly

    PubMed Central

    Jayabalan, Aravinth Kumar; Sanchez, Anthony; Park, Ra Young; Yoon, Sang Pil; Kang, Gum-Yong; Baek, Je-Hyun; Anderson, Paul; Kee, Younghoon; Ohn, Takbum

    2016-01-01

    Stress granules (SGs) harbour translationally stalled messenger ribonucleoproteins and play important roles in regulating gene expression and cell fate. Here we show that neddylation promotes SG assembly in response to arsenite-induced oxidative stress. Inhibition or depletion of key components of the neddylation machinery concomitantly inhibits stress-induced polysome disassembly and SG assembly. Affinity purification and subsequent mass-spectrometric analysis of Nedd8-conjugated proteins from translationally stalled ribosomal fractions identified ribosomal proteins, translation factors and RNA-binding proteins (RBPs), including SRSF3, a previously known SG regulator. We show that SRSF3 is selectively neddylated at Lys85 in response to arsenite. A non-neddylatable SRSF3 (K85R) mutant do not prevent arsenite-induced polysome disassembly, but fails to support the SG assembly, suggesting that the neddylation pathway plays an important role in SG assembly. PMID:27381497

  7. The Chlamydomonas heat stress response.

    PubMed

    Schroda, Michael; Hemme, Dorothea; Mühlhaus, Timo

    2015-05-01

    Heat waves occurring at increased frequency as a consequence of global warming jeopardize crop yield safety. One way to encounter this problem is to genetically engineer crop plants toward increased thermotolerance. To identify entry points for genetic engineering, a thorough understanding of how plant cells perceive heat stress and respond to it is required. Using the unicellular green alga Chlamydomonas reinhardtii as a model system to study the fundamental mechanisms of the plant heat stress response has several advantages. Most prominent among them is the suitability of Chlamydomonas for studying stress responses system-wide and in a time-resolved manner under controlled conditions. Here we review current knowledge on how heat is sensed and signaled to trigger temporally and functionally grouped sub-responses termed response elements to prevent damage and to maintain cellular homeostasis in plant cells. PMID:25754362

  8. Improved Heat-Stress Algorithm

    NASA Technical Reports Server (NTRS)

    Teets, Edward H., Jr.; Fehn, Steven

    2007-01-01

    NASA Dryden presents an improved and automated site-specific algorithm for heat-stress approximation using standard atmospheric measurements routinely obtained from the Edwards Air Force Base weather detachment. Heat stress, which is the net heat load a worker may be exposed to, is officially measured using a thermal-environment monitoring system to calculate the wet-bulb globe temperature (WBGT). This instrument uses three independent thermometers to measure wet-bulb, dry-bulb, and the black-globe temperatures. By using these improvements, a more realistic WBGT estimation value can now be produced. This is extremely useful for researchers and other employees who are working on outdoor projects that are distant from the areas that the Web system monitors. Most importantly, the improved WBGT estimations will make outdoor work sites safer by reducing the likelihood of heat stress.

  9. Stress fractures and bone pain

    SciTech Connect

    Groshar, D.; Even-Sapir, E.; Lam, M.; Israel, O.; Front, D.

    1984-01-01

    Stress fractures result from an unusual repetitive physical activity causing absorption of bone in excess of repair and bone formation. This leads to the weakening of the bone and subsequently to a fracture. It is a benign condition that if recognized in time does not need any treatment besides rest. However, if diagnosis is not made and physical activity continues it may result in severe injury to the bone and a frank fracture may result. Pain is the typical clinical feature and bone scintigraphy, being more sensitive than radiography, is done to establish early diagnosis. The presence of asymptomatic sites of abnormal bone uptake typical of stress fracture in which pain appeared only about 2 weeks after scintigraphy, drew the authors' attention to the question of how close is the relationship between stress fractures and bone pain. Sixty-four military recruits diagnosed as suffering from stress fracture were investigated in order to correlate sites with abnormal uptake of Tc-99m MDP on bone scintigraphy with sites of local pain. In 37 (58%) subjects multiple sites of abnormal uptake were recognised. Of 123 sites of abnormal uptake, 31 (25%) were asymptomatic. In three patients bone pain appeared at the site of the abnormal uptake two weeks after scintigraphy. Bone scintigraphy appears to be more sensitive than bone pain in the diagnosis of stress fractures. The osteoblastic activity which manifests itself by abnormal uptake appears in some cases earlier than the pain caused by the fracture. Present findings may suggest that under certain circumstances, in a population prone to stress fracture, bone scan should be considered as a screening method.

  10. [Glucose metabolic changes in stress].

    PubMed

    Foia, L; Costuleanu, N; Trandafirescu, M; Saila, V; Pavel, M

    1999-01-01

    Provision of a better understanding of the pathogenic pathways underlying injured sugar metabolism during stress should ideally translate into a more rational approach to the provision of nutritional support. Patients with burns, trauma, severe injuries or infections commonly develop a hypermetabolic state that is associated with several changes in carbohydrate metabolism. The hypermetabolic state is induced either by the area of injury and by organs involved in the immunologic response to stress; further it determines a glycemic milieu which will be directed toward satisfaction of the requirements for glucose as an energy support. PMID:10756928

  11. Stress corrosion and hydrogen embrittlement

    NASA Technical Reports Server (NTRS)

    Blackburn, M. J.; Smyrl, W. H.

    1973-01-01

    Service experience applications, experimental data generation, and the development of satisfactory quantitative theories relevant to the suppression and control of stress corrosion cracking in titanium are discussed. The impact of stress corrosion cracking (SCC) on the use of titanium alloys is considered, with emphasis on utilization in the aerospace field. Recent data on hot salt SCC, crack growth in hydrogen gas, and crack growth in liquid environments containing halide ions are reviewed. The status of the understanding of crack growth processes in these environments is also examined.

  12. Endoplasmic Reticulum Stress and Cancer

    PubMed Central

    Yadav, Raj Kumar; Chae, Soo-Wan; Kim, Hyung-Ryong; Chae, Han Jung

    2014-01-01

    The endoplasmic reticulum (ER) is the principal organelle responsible for multiple cellular functions including protein folding and maturation and the maintenance of cellular homeostasis. ER stress is activated by a variety of factors and triggers the unfolded protein response (UPR), which restores homeostasis or activates cell death. Multiple studies have clarified the link between ER stress and cancer, and particularly the involvement of the UPR. The UPR seems to adjust the paradoxical microenvironment of cancer and, as such, is one of resistance mechanisms against cancer therapy. This review describes the activity of different UPRs involved in tumorigenesis and resistance to cancer therapy. PMID:25337575

  13. Oxidative Stress in Atopic Dermatitis

    PubMed Central

    Ji, Hongxiu; Li, Xiao-Kang

    2016-01-01

    Atopic dermatitis (AD) is a chronic pruritic skin disorder affecting many people especially young children. It is a disease caused by the combination of genetic predisposition, immune dysregulation, and skin barrier defect. In recent years, emerging evidence suggests oxidative stress may play an important role in many skin diseases and skin aging, possibly including AD. In this review, we give an update on scientific progress linking oxidative stress to AD and discuss future treatment strategies for better disease control and improved quality of life for AD patients. PMID:27006746

  14. Sustained stress response after oxidative stress in trabecular meshwork cells

    PubMed Central

    Li, Guorong; Luna, Coralia; Liton, Paloma B.; Navarro, Iris; Epstein, David L.

    2007-01-01

    Purpose To investigate the mechanisms by which chronic oxidative stress may lead to a sustained stress response similar to that previously observed in the trabecular meshwork (TM) of glaucoma donors. Methods Porcine TM cells were treated with 200 μM H2O2 twice a day for four days and were allowed to recover for three additional days. After the treatment, TM cells were analyzed for generation of intracellular reactive oxygen species (iROS), mitochondrial potential, activation of NF-κB, and the expression of inflammatory markers IL-1α, IL-6, IL-8, and ELAM-1. Potential sources of iROS were evaluated using inhibitors for nitric oxide, nitric oxide synthetase, cyclooxygenase, xanthine oxidase, NADPH oxidase, mitochondrial ROS, and PKC. The role of NF-κB activation in the induction of inflammatory markers was evaluated using the inhibitors Lactacystin and BAY11–7082. Results Chronic oxidative stress simulated by H2O2 exposure of porcine TM cells resulted in the sustained production of iROS by the mitochondria. Inhibition of mitochondrial iROS had a significant inhibitory effect on the activation of NF-κB and the induction of IL-1α, IL-6, IL-8, and ELAM-1 triggered by chronic oxidative stress. Inhibition of NF-κB partially prevented the induction of IL-1α, IL-8, and ELAM-1, but not IL-6. Conclusions Chronic oxidative stress in TM cells induced iROS production in mitochondria. This increase in iROS may contribute to the pathogenesis of the TM in glaucoma by inducing the expression of inflammatory mediators previously observed in glaucoma donors as well as the levels of oxidative damage in the tissue. PMID:18199969

  15. Une formation à la recherche en médecine transfusionnelle dans le monde francophone

    PubMed Central

    Shiboski, C.; Fontanet, A.; Murphy, E.L.

    2010-01-01

    Un enseignement accéléré et francophone de formation à la recherche en médecine transfusionnelle a été récemment instauré à l’Institut Pasteur de Paris, sous la codirection de membres hospitalo-universitaires de l’université de Californie San Francisco (UCSF), du Blood Systems Research Institute (BSRI) et de l’Institut national de la transfusion sanguine (INTS). Le but est de former des professionnels de la transfusion des pays en voie de développement à mener une activité de recherche dont les résultats peuvent contribuer à un renforcement de la qualité des soins transfusionnels et de la sécurité transfusionnelle dans leur pays. Le cours enseigne les méthodes de recherche clinique et épidémiologique, et leurs applications transfusionnelles potentielles. Chaque étudiant élabore au cours du stage un protocole personnel de recherche, qu’il lui sera loisible de mettre ensuite en pratique dans le centre de transfusion ou l’hôpital où il exerce. PMID:19640755

  16. Les succédanés du sucre durant la grossesse

    PubMed Central

    Pope, Eliza; Koren, Gideon; Bozzo, Pina

    2014-01-01

    Résumé Question J’ai une patiente enceinte qui consomme souvent des succédanés du sucre et elle m’a demandé si cette pratique continue pouvait nuire à sa grossesse ou à son enfant. Que devrais-je lui répondre et existe-t-il d’autres meilleurs choix durant la grossesse? Réponse Il faudrait faire plus de recherche pour déterminer plus exactement les effets de l’exposition aux succédanés du sucre in utero, mais les données disponibles ne laissent pas présager d’effets indésirables durant la grossesse. Toutefois, il est recommandé de consommer des substituts du sucre en quantités modérées et de se conformer aux doses journalières admissibles établies par les organismes de règlementation.

  17. Being Irrationally Funny as a Cognitive Psychologist: Interview With Dan Ariely.

    PubMed

    Ariely, Dan; Popescu, Beatrice

    2015-11-01

    The idea of interviewing Dan Ariely was somehow latent on my mind since I started being interested in cognitive psychology and cognitive behavior psychotherapy, but actually got more ardent ever since irrationality became a research topic for his team at Duke University. I picked him as an interviewee thinking not only at his exceptional skills as a researcher and as Kahnemann 'disciple', but mainly for his fantastic wit, true modesty and utmost interest in making people's lives easier and more comfortable, by creating awareness on a lot of topics otherwise neglected. Dan Ariely's very agreeable personality and humor would not let you think of him as a burnt casualty who, in his youth struggled to survive a personal drama, so well-documented in his paper "Painful lessons" posted on the MIT website (http://web.mit.edu/ariely/www/MIT/Papers/mypain.pdf). I think reading his paper and also this transcribed interview with him would be also comforting for people who found out about Bucharest fire incident that rocked our society and also for people who are personally related to this tragedy. PMID:27247678

  18. Molecular dynamics at constant Cauchy stress

    NASA Astrophysics Data System (ADS)

    Miller, Ronald E.; Tadmor, Ellad B.; Gibson, Joshua S.; Bernstein, Noam; Pavia, Fabio

    2016-05-01

    The Parrinello-Rahman algorithm for imposing a general state of stress in periodic molecular dynamics simulations is widely used in the literature and has been implemented in many readily available molecular dynamics codes. However, what is often overlooked is that this algorithm controls the second Piola-Kirchhoff stress as opposed to the true (Cauchy) stress. This can lead to misinterpretation of simulation results because (1) the true stress that is imposed during the simulation depends on the deformation of the periodic cell, (2) the true stress is potentially very different from the imposed second Piola-Kirchhoff stress, and (3) the true stress can vary significantly during the simulation even if the imposed second Piola-Kirchhoff is constant. We propose a simple modification to the algorithm that allows the true Cauchy stress to be controlled directly. We then demonstrate the efficacy of the new algorithm with the example of martensitic phase transformations under applied stress.

  19. Molecular dynamics at constant Cauchy stress.

    PubMed

    Miller, Ronald E; Tadmor, Ellad B; Gibson, Joshua S; Bernstein, Noam; Pavia, Fabio

    2016-05-14

    The Parrinello-Rahman algorithm for imposing a general state of stress in periodic molecular dynamics simulations is widely used in the literature and has been implemented in many readily available molecular dynamics codes. However, what is often overlooked is that this algorithm controls the second Piola-Kirchhoff stress as opposed to the true (Cauchy) stress. This can lead to misinterpretation of simulation results because (1) the true stress that is imposed during the simulation depends on the deformation of the periodic cell, (2) the true stress is potentially very different from the imposed second Piola-Kirchhoff stress, and (3) the true stress can vary significantly during the simulation even if the imposed second Piola-Kirchhoff is constant. We propose a simple modification to the algorithm that allows the true Cauchy stress to be controlled directly. We then demonstrate the efficacy of the new algorithm with the example of martensitic phase transformations under applied stress. PMID:27179471

  20. Social support, stress and the aging brain.

    PubMed

    Sherman, Stephanie M; Cheng, Yen-Pi; Fingerman, Karen L; Schnyer, David M

    2016-07-01

    Social support benefits health and well-being in older individuals, however the mechanism remains poorly understood. One proposal, the stress-buffering hypothesis states social support 'buffers' the effects of stress on health. Alternatively, the main effect hypothesis suggests social support independently promotes health. We examined the combined association of social support and stress on the aging brain. Forty healthy older adults completed stress questionnaires, a social network interview and structural MRI to investigate the amygdala-medial prefrontal cortex circuitry, which is implicated in social and emotional processing and negatively affected by stress. Social support was positively correlated with right medial prefrontal cortical thickness while amygdala volume was negatively associated with social support and positively related to stress. We examined whether the association between social support and amygdala volume varied across stress level. Stress and social support uniquely contribute to amygdala volume, which is consistent with the health benefits of social support being independent of stress. PMID:26060327

  1. Clinical experimental stress studies: methods and assessment.

    PubMed

    Bali, Anjana; Jaggi, Amteshwar Singh

    2015-01-01

    Stress is a state of threatened homeostasis during which a variety of adaptive processes are activated to produce physiological and behavioral changes. Stress induction methods are pivotal for understanding these physiological or pathophysiological changes in the body in response to stress. Furthermore, these methods are also important for the development of novel pharmacological agents for stress management. The well-described methods to induce stress in humans include the cold pressor test, Trier Social Stress Test, Montreal Imaging Stress Task, Maastricht Acute Stress Test, CO2 challenge test, Stroop test, Paced Auditory Serial Addition Task, noise stress, and Mannheim Multicomponent Stress Test. Stress assessment in humans is done by measuring biochemical markers such as cortisol, cortisol awakening response, dexamethasone suppression test, salivary α-amylase, plasma/urinary norepinephrine, norepinephrine spillover rate, and interleukins. Physiological and behavioral changes such as galvanic skin response, heart rate variability, pupil size, and muscle and/or skin sympathetic nerve activity (microneurography) and cardiovascular parameters such as heart rate, blood pressure, and self-reported anxiety are also monitored to assess stress response. This present review describes these commonly employed methods to induce stress in humans along with stress assessment methods. PMID:26020552

  2. Quantifying renewable groundwater stress with GRACE

    NASA Astrophysics Data System (ADS)

    Richey, Alexandra S.; Thomas, Brian F.; Lo, Min-Hui; Reager, John T.; Famiglietti, James S.; Voss, Katalyn; Swenson, Sean; Rodell, Matthew

    2015-07-01

    Groundwater is an increasingly important water supply source globally. Understanding the amount of groundwater used versus the volume available is crucial to evaluate future water availability. We present a groundwater stress assessment to quantify the relationship between groundwater use and availability in the world's 37 largest aquifer systems. We quantify stress according to a ratio of groundwater use to availability, which we call the Renewable Groundwater Stress ratio. The impact of quantifying groundwater use based on nationally reported groundwater withdrawal statistics is compared to a novel approach to quantify use based on remote sensing observations from the Gravity Recovery and Climate Experiment (GRACE) satellite mission. Four characteristic stress regimes are defined: Overstressed, Variable Stress, Human-dominated Stress, and Unstressed. The regimes are a function of the sign of use (positive or negative) and the sign of groundwater availability, defined as mean annual recharge. The ability to mitigate and adapt to stressed conditions, where use exceeds sustainable water availability, is a function of economic capacity and land use patterns. Therefore, we qualitatively explore the relationship between stress and anthropogenic biomes. We find that estimates of groundwater stress based on withdrawal statistics are unable to capture the range of characteristic stress regimes, especially in regions dominated by sparsely populated biome types with limited cropland. GRACE-based estimates of use and stress can holistically quantify the impact of groundwater use on stress, resulting in both greater magnitudes of stress and more variability of stress between regions.

  3. Quantifying renewable groundwater stress with GRACE

    PubMed Central

    Richey, Alexandra S.; Thomas, Brian F.; Lo, Min‐Hui; Reager, John T.; Voss, Katalyn; Swenson, Sean; Rodell, Matthew

    2015-01-01

    Abstract Groundwater is an increasingly important water supply source globally. Understanding the amount of groundwater used versus the volume available is crucial to evaluate future water availability. We present a groundwater stress assessment to quantify the relationship between groundwater use and availability in the world's 37 largest aquifer systems. We quantify stress according to a ratio of groundwater use to availability, which we call the Renewable Groundwater Stress ratio. The impact of quantifying groundwater use based on nationally reported groundwater withdrawal statistics is compared to a novel approach to quantify use based on remote sensing observations from the Gravity Recovery and Climate Experiment (GRACE) satellite mission. Four characteristic stress regimes are defined: Overstressed, Variable Stress, Human‐dominated Stress, and Unstressed. The regimes are a function of the sign of use (positive or negative) and the sign of groundwater availability, defined as mean annual recharge. The ability to mitigate and adapt to stressed conditions, where use exceeds sustainable water availability, is a function of economic capacity and land use patterns. Therefore, we qualitatively explore the relationship between stress and anthropogenic biomes. We find that estimates of groundwater stress based on withdrawal statistics are unable to capture the range of characteristic stress regimes, especially in regions dominated by sparsely populated biome types with limited cropland. GRACE‐based estimates of use and stress can holistically quantify the impact of groundwater use on stress, resulting in both greater magnitudes of stress and more variability of stress between regions. PMID:26900185

  4. Prediction inverse d'un front de solidification dans un four de transformation a haute temperature

    NASA Astrophysics Data System (ADS)

    Marois, Marc-Andre

    Ce projet de recherche porte sur une methode numerique permettant de predire l'evolution du profil 2D de la couche solide qui recouvre l'interieur des parois de plusieurs fours de transformation a haute temperature. Un modele mathematique base sur la formulation faible de l'energie est d'abord developpe et valide. Une methode de transfert thermique inverse reposant sur ce modele est ensuite developpee afin d'obtenir une mesure rapide et continue de l'evolution du profil de cette couche solide. Vu la grande inertie thermique du systeme a l'etude, differentes strategies sont proposees afin de faciliter la mise en uvre de cette methode numerique. Finalement, cette approche inverse est confrontee aux resultats experimentaux obtenus a l'aide d'un reacteur metallurgique. Une etude preliminaire montre que les fours de transformation presentent une tres grande inertie thermique qui limite grandement l'utilisation des methodes inverses. En effet, la sensibilite de cette methode numerique repose essentiellement sur le delai temporel observe entre la variation du profil du banc et la fluctuation de la temperature a la surface externe de la paroi du four. Les resultats obtenus demontrent qu'une partie de ce delai est proportionnel a la chaleur latente de fusion lorsque le materiau a changement de phase est constitue d'un melange non eutectique. Afin de limiter l'impact de ce delai temporel, deux astuces numeriques sont proposees : reutiliser plus d'une fois les mesures de temperature et modifier le probleme thermique dans les regions pateuse et liquide. D'une part, le concept de chevauchement propose permet de reduire le temps d'acquisition des donnees entre chacune des predictions. D'autre part, l'approche virtuelle developpee permet de reduire l'inertie thermique du systeme et, par le fait meme, le delai temporel associe a la diffusion de la chaleur. Ces deux strategies ont permis de predire efficacement l'evolution 1D de l'epaisseur de la couche de gelee qui se solidifie a

  5. Etude theorique des fluctuations structurales dans les composes organiques a dimensionnalite reduite

    NASA Astrophysics Data System (ADS)

    Dumoulin, Benoit

    Les systemes a dimensionnalite reduite constituent maintenant une branche entiere de la physique de la matiere condensee. Cette derniere s'est developpee rapidement au cours des dernieres annees, avec la decouverte des materiaux organiques qui presentent, justement, des proprietes physiques fortement anisotropes. Cette these presente une etude en trois parties de plusieurs composes organiques qui, bien que tres differents du point de vue de leurs compositions chimiques et de leurs proprietes physiques a haute temperature, subissent tous une instabilite structurale a tres basse temperature. De plus, dans chacun des cas, l'instabilite structurale est precedee d'un important regime fluctuatif a partir duquel les proprietes physiques changent de maniere significative. Notre etude suit un ordre chronologique inverse puisque nous nous attardons en premier lieu au cas de composes recemment decouverts: les composes de la famille des (BCPTTF)2X (X = PF6 , AsF6). Ces derniers sont des isolants magnetiques a la temperature ambiante et subissent une instabilite structurale de type spin-Peierls a une temperature appelee TSP. En particulier, nous nous interessons a l'etude des proprietes physiques de ces systemes dans le regime fluctuatif, qui precede cette instabilite. Notre etude theorique nous permet de comprendre en detail comment ces systemes s'approchent de l'instabilite struturale. Dans la seconde partie de cette these, nous etudions le regime fluctuatif (pre-transitionnel) observe experimentalement dans le compose de (TMTTF)2PF6. Ce compose organique, dont la structure s'apparente aux sels de Bechgaard, subit une instabilite de type spin-Peierls a une temperature T SP = 19K. Bien que ce compose possede la particularite d'etre un bon conducteur a la temperature ambiante, il subit une transition de type Mott-Hubbard a une temperature Trho ≈ 220K et devient alors un isolant magnetique, analogue aux composes de la famille des (BCPTTF)2X. Le regime fluctuatif precedant l

  6. Les Elements Legers: Diffusion dans les Enveloppes Stellaires et Implications Cosmologiques

    NASA Astrophysics Data System (ADS)

    Richer, Jacques

    1992-01-01

    Les observations des abondances des elements legers (Z <= 5) sont utilisees pour estimer la quantitie de lithium qui a ete produite lors du Big -Bang, et obtenir simultanement des contraintes sur la nature des inhomogeneites qui ont pu exister durant la nucleosynthese primordiale. Nous utilisons un modele simple capable de simuler approximativement la diffusion et la retro-diffusion des neutrons a travers la matiere inhomogene durant les premieres minutes de l'expansion de l'Univers. Nous tenons compte de la difference possible entre l'abondance primordiale de Li et les abondances observees dans les plus vieilles etoiles. Cette difference (un facteur 2, environ) est estimee en construisant des modeles evolutifs d'etoiles peu massives de Population II, incluant la sedimentation gravitationnelle du lithium et de l'helium. Ces modeles montrent egalement que les ages des vieux amas stellaires sont grandement surestimes lorsqu'ils sont determines a partir de modeles stellaires n'incluant pas l'effet de la diffusion de He. Nous calculons ensuite comment evoluent les abondances de Li et Be dans des etoiles plus massives et plus jeunes, de la pre-sequence principale ou de la ZAMS, jusqu'a l'epuisement de leur hydrogene central. Les modeles incluent la sedimentation simultanee de l'helium a travers l'enveloppe. Une approche hierarchique (evolution du coeur--evolution de l'enveloppe --tri des elements traces) est utilisee pour simuler efficacement le grand nombre d'etoiles necessaire pour la construction d'isochrones. Une attention particuliere est portee aux consequences de la sedimentation de He sur l'etendue des zones convectives, et sur la diffusion de Li et Be. Les forces radiatives agissant sur ces deux elements sont calculees en detail a partir des donnees atomiques. Les etoiles simulees correspondent approximativement aux types spectraux A, F, et AmFm. Les abondances de Li et Be observees dans les etoiles jeunes de ces types sont comparees a nos predictions dans le

  7. The impact of static stress change, dynamic stress change, and the background stress on aftershock focal mechanisms

    USGS Publications Warehouse

    Hardebeck, Jeanne L.

    2014-01-01

    The focal mechanisms of earthquakes in Southern California before and after four M ≥ 6.7 main shocks provide insight into how fault systems respond to stress and changes in stress. The main shock static stress changes have two observed impacts on the seismicity: changing the focal mechanisms in a given location to favor those aligned with the static stress change and changing the spatial distribution of seismicity to favor locations where the static stress change aligns with the background stress. The aftershock focal mechanisms are significantly aligned with the static stress changes for absolute stress changes of ≥ 0.02 MPa, for up to ~20 years following the main shock. The dynamic stress changes have similar, although smaller, effects on the local focal mechanisms and the spatial seismicity distribution. Dynamic stress effects are best observed at long periods (30–60 s) and for metrics based on repeated stress cycling in the same direction. This implies that dynamic triggering operates, at least in part, through cyclic shear stress loading in the direction of fault slip. The background stress also strongly controls both the preshock and aftershock mechanisms. While most aftershock mechanisms are well oriented in the background stress field, 10% of aftershocks are identified as poorly oriented outliers, which may indicate limited heterogeneity in the postmain shock stress field. The fault plane orientations of the outliers are well oriented in the background stress, while their slip directions are not, implying that the background stress restricts the distribution of available fault planes.

  8. Evolution of concepts of stress.

    PubMed

    Goldstein, David S; Kopin, Irwin J

    2007-06-01

    This essay describes the evolution of stress as a medical scientific idea. Claude Bernard, Walter B. Cannon and Hans Selye provided key founding concepts for the current view. Bernard introduced the idea of the internal environment bathing cells - the milieu intérieur - maintained by continual compensatory changes of bodily functions. Cannon coined the word, "homeostasis," referring to a set of acceptable ranges of values for internal variables. Cannon taught that threats to homeostasis evoke activation of the sympathoadrenal system as a functional unit. Selye defined stress as a state characterized by a uniform response pattern, regardless of the particular stressor, that could lead to long-term pathologic changes. "Allostasis" was introduced as a concept in recognition that there is no single ideal set of steady-state conditions in life; instead, setpoints and other response criteria change continuously. Stress is now viewed neither as a perturbation nor a stereotyped response pattern but as a condition characterized by a perceived discrepancy between information about a monitored variable and criteria for eliciting patterned effector responses. Different stressors elicit different patterns of activation of the sympathetic nervous, adrenomedullary hormonal, hypothalamic-pituitary-adrenocortical and other effectors, closing negative feedback loops. This systems concept of stress yields predictions that observation or experimentation can test and that are applicable to normal physiology and to a variety of acute and chronic disorders. PMID:17514579

  9. Soil microbiology under drought stress

    Technology Transfer Automated Retrieval System (TEKTRAN)

    he severity of the 2012 drought affecting much of the Midwestern U.S. is readily observed in the extremely stressed conditions of crops and natural vegetation. However, we may not realize that the extent of drought effects is just as severe on the biology below the soil surface. Detrimental effects ...

  10. Stroking Stressed-Out Teachers

    ERIC Educational Resources Information Center

    Black, Susan

    2004-01-01

    Stress seems to be a way of life for teachers. Many teachers describe themselves as over-whelmed. They admit to feeling anxious and apprehensive, especially about meeting the mounting needs of troubled students, doing justice to an all-consuming curriculum, and getting kids ready for a relentless series of tests. According to a study of Midwestern…

  11. Hypoxia, Oxidative Stress and Fat.

    PubMed

    Netzer, Nikolaus; Gatterer, Hannes; Faulhaber, Martin; Burtscher, Martin; Pramsohler, Stephan; Pesta, Dominik

    2015-01-01

    Metabolic disturbances in white adipose tissue in obese individuals contribute to the pathogenesis of insulin resistance and the development of type 2 diabetes mellitus. Impaired insulin action in adipocytes is associated with elevated lipolysis and increased free fatty acids leading to ectopic fat deposition in liver and skeletal muscle. Chronic adipose tissue hypoxia has been suggested to be part of pathomechanisms causing dysfunction of adipocytes. Hypoxia can provoke oxidative stress in human and animal adipocytes and reduce the production of beneficial adipokines, such as adiponectin. However, time-dose responses to hypoxia relativize the effects of hypoxic stress. Long-term exposure of fat cells to hypoxia can lead to the production of beneficial substances such as leptin. Knowledge of time-dose responses of hypoxia on white adipose tissue and the time course of generation of oxidative stress in adipocytes is still scarce. This paper reviews the potential links between adipose tissue hypoxia, oxidative stress, mitochondrial dysfunction, and low-grade inflammation caused by adipocyte hypertrophy, macrophage infiltration and production of inflammatory mediators. PMID:26061760

  12. Managing Teacher Stress and Burnout.

    ERIC Educational Resources Information Center

    Sparks, Dennis; Hammond, Janice

    This monograph offers a practical guide for identifying and managing those stressors that are in the specific domain of the individual--exercise, diet, sleep, interpersonal relations, time and conflict management, and relaxation. The first section covers stress theory; methods to identify and clarify stressors; restoration of a balanced…

  13. The Sport-Stress Connection.

    ERIC Educational Resources Information Center

    Santomier, James

    1983-01-01

    This article explains how and why stress mechanisms operate in students who participate in sports. Students respond to different sport situations with various physical, psychological, and social reactions. When developing and supervising sports, school personnel should take into consideration the physical and psychological development of…

  14. The stress and underground environment

    NASA Astrophysics Data System (ADS)

    Chama, A.

    2009-04-01

    Currently,the program of prevention in occupational health needs mainly to identify occupational hazards and strategy of their prevention.Among these risks,the stress represents an important psycho-social hazard in mental health,which unfortunately does not spare no occupation.My Paper attempts to highlight and to develop this hazard in its different aspects even its regulatory side in underground environment as occupational environment.In the interest of better prevention ,we consider "the information" about the impact of stress as the second prevention efficient and no expensive to speleologists,hygienists and workers in the underground areas. In this occasion of this event in Vienna,we also highlight the scientific works on the stress of the famous viennese physician and endocrinologist Doctor Hans Selye (1907-1982),nicknamed "the father of stress" and note on relation between biological rhythms in this underground area and psychological troubles (temporal isolation) (Jurgen Aschoff’s works and experiences out-of time).

  15. Stressing out the Social Network.

    PubMed

    Kirkby, Lowry A; Sohal, Vikaas S

    2016-07-20

    In this issue of Neuron, Hultman et al. (2016) find that stress-induced abnormal social behavior reflects aberrant prefrontal regulation of downstream limbic networks. This illustrates how linking aberrant network dynamics to neuropsychiatric disorders may lead to new circuit-based therapeutic interventions. PMID:27477012

  16. Thermal anomalies in stressed Teflon.

    NASA Technical Reports Server (NTRS)

    Lee, S. H.; Wulff, C. A.

    1972-01-01

    In the course of testing polytetrafluoroethylene (Teflon) as a calorimetric gasketing material, serendipity revealed a thermal anomaly in stressed film that occurs concomitantly with the well-documented 25 C transition. The magnitude of the excess energy absorption - about 35 cal/g - is suggested to be related to the restricted thermal expansion of the film.

  17. Stress Voiding During Wafer Processing

    SciTech Connect

    Yost, F.G.

    1999-03-01

    Wafer processing involves several heating cycles to temperatures as high as 400 C. These thermal excursions are known to cause growth of voids that limit reliability of parts cut from the wafer. A model for void growth is constructed that can simulate the effect of these thermal cycles on void growth. The model is solved for typical process steps and the kinetics and extent of void growth are determined for each. It is shown that grain size, void spacing, and conductor line width are very important in determining void and stress behavior. For small grain sizes, stress relaxation can be rapid and can lead to void shrinkage during subsequent heating cycles. The effect of rapid quenching from process temperatures is to suppress void growth but induce large remnant stress in the conductor line. This stress can provide the driving force for void growth during storage even at room temperature. For isothermal processes the model can be solved analytically and estimates of terminal void size a nd lifetime are obtained.

  18. Stress evolution during caldera collapse

    NASA Astrophysics Data System (ADS)

    Holohan, E. P.; Schöpfer, M. P. J.; Walsh, J. J.

    2015-07-01

    The mechanics of caldera collapse are subject of long-running debate. Particular uncertainties concern how stresses around a magma reservoir relate to fracturing as the reservoir roof collapses, and how roof collapse in turn impacts upon the reservoir. We used two-dimensional Distinct Element Method models to characterise the evolution of stress around a depleting sub-surface magma body during gravity-driven collapse of its roof. These models illustrate how principal stress orientations rotate during progressive deformation so that roof fracturing transitions from initial reverse faulting to later normal faulting. They also reveal four end-member stress paths to fracture, each corresponding to a particular location within the roof. Analysis of these paths indicates that fractures associated with ultimate roof failure initiate in compression (i.e. as shear fractures). We also report on how mechanical and geometric conditions in the roof affect pre-failure unloading and post-failure reloading of the reservoir. In particular, the models show how residual friction within a failed roof could, without friction reduction mechanisms or fluid-derived counter-effects, inhibit a return to a lithostatically equilibrated pressure in the magma reservoir. Many of these findings should be transferable to other gravity-driven collapse processes, such as sinkhole formation, mine collapse and subsidence above hydrocarbon reservoirs.

  19. Oxidative Stress Markers in Sputum

    PubMed Central

    Antus, Balazs

    2016-01-01

    Although oxidative stress is thought to play a pivotal role in the pathogenesis of inflammatory airway diseases, its assessment in clinical practice remains elusive. In recent years, it has been conceptualized that oxidative stress markers in sputum should be employed to monitor oxidative processes in patients with asthma, chronic obstructive pulmonary disease (COPD), or cystic fibrosis (CF). In this review, the use of sputum-based oxidative markers was explored and potential clinical applications were considered. Among lipid peroxidation-derived products, 8-isoprostane and malondialdehyde have been the most frequently investigated, while nitrosothiols and nitrotyrosine may serve as markers of nitrosative stress. Several studies have showed higher levels of these products in patients with asthma, COPD, or CF compared to healthy subjects. Marker concentrations could be further increased during exacerbations and decreased along with recovery of these diseases. Measurement of oxidized guanine species and antioxidant enzymes in the sputum could be other approaches for assessing oxidative stress in pulmonary patients. Collectively, even though there are promising findings in this field, further clinical studies using more established detection techniques are needed to clearly show the benefit of these measurements in the follow-up of patients with inflammatory airway diseases. PMID:26885248

  20. Combating Training-Stress Syndromes.

    ERIC Educational Resources Information Center

    Voight, Mike

    2002-01-01

    Addresses the nature and ramifications of various training stress syndromes (overtraining, under-recovery, distress, staleness, and burnout) that can accompany inappropriate training practices, examining the interventions that players and coaches can use to combat these syndromes (including physical, psychological, and performance interventions),…

  1. Radiative recombination in stressed superlattices

    SciTech Connect

    Gorya, O.S.; Keyanu, A.S.; Tatarinskaya, O.M.

    1995-11-01

    The properties of superlattices (SL) formed by layers with different lattice constants differ from the properties of isoperiodic SLs because of the presence in the layers of appreciable stresses containing both hydrostatic and uniaxial components. The energy levels of stressed SLs at a fixed composition of the layers are governed by two mechanisms. First, the energy of the SL bands relative to the bottom of the corresponding quantum wells is determined by the width and depth of the well, as well as by the distance to other wells. In particular, if at a fixed distance between wells, the authors increase their width, the minimum energies of the superlattice bands relative to the bottom of the well will decrease (quantum dimensional effect). This behavior is usually observed in isoperiodic SLs. Second, the energy of the bottom and edges of wells depends on the stresses in the layers, which, in turn, are determined by the thickness ratio of the layers. Thus, if at a fixed spacing between the wells, their width is changed, the energies of the bottom and of the edge of the wells will change. Such behavior is typical only of stressed SLs.

  2. Oxidative Stress and Neurodegenerative Disorders

    PubMed Central

    Li, Jie; O, Wuliji; Li, Wei; Jiang, Zhi-Gang; Ghanbari, Hossein A.

    2013-01-01

    Living cells continually generate reactive oxygen species (ROS) through the respiratory chain during energetic metabolism. ROS at low or moderate concentration can play important physiological roles. However, an excessive amount of ROS under oxidative stress would be extremely deleterious. The central nervous system (CNS) is particularly vulnerable to oxidative stress due to its high oxygen consumption, weakly antioxidative systems and the terminal-differentiation characteristic of neurons. Thus, oxidative stress elicits various neurodegenerative diseases. In addition, chemotherapy could result in severe side effects on the CNS and peripheral nervous system (PNS) of cancer patients, and a growing body of evidence demonstrates the involvement of ROS in drug-induced neurotoxicities as well. Therefore, development of antioxidants as neuroprotective drugs is a potentially beneficial strategy for clinical therapy. In this review, we summarize the source, balance maintenance and physiologic functions of ROS, oxidative stress and its toxic mechanisms underlying a number of neurodegenerative diseases, and the possible involvement of ROS in chemotherapy-induced toxicity to the CNS and PNS. We ultimately assess the value for antioxidants as neuroprotective drugs and provide our comments on the unmet needs. PMID:24351827

  3. Relationships between Stress and Immunity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stress, as it relates to bodily functions, has been defined as the sum of all biologic reactions to physical, emotional, or mental stimuli that disturb an individual’s homeostasis. Therefore, a stressor can be defined as any internal or external stimuli or threat that disrupts homeostasis of the bod...

  4. "Stressing" Relaxation in the Classroom.

    ERIC Educational Resources Information Center

    Prager-Decker, Iris

    A rationale is offered for incorporating relaxation training in elementary school classroom activities. Cited are research studies which focus on the reaction of children to stressful life changes and resulting behavioral and physical disorders. A list is given of significant life events which may be factors in causing diseases or misbehavior in…

  5. Stressed Out in the Classroom.

    ERIC Educational Resources Information Center

    Black, Susan

    2003-01-01

    Many teachers feel overwhelmed about meeting the needs of students getting ready for tests, and about relations with principals. Four exceptionally high-stress factors that teachers admit carrying into their classrooms are money management, health, relationships, and care giving. A sidebar lists tips for administrators to help alleviate teachers'…

  6. Alcohol Effects on Stress Pathways

    PubMed Central

    Blaine, Sara K.; Milivojevic, Verica; Fox, Helen

    2016-01-01

    A significant amount of neurobiological research regarding the development of alcohol use disorders (AUDs) has focused on alcohol-related activation and long-term alterations in the mesocortical dopaminergic reward pathways. However, alcohol does not only interact with brain reward systems. Many of its acute and chronic effects may be related to allostatic adaptations in hypothalamic and extrahypothalamic stress regulation pathways. For example, acute binge intoxication is associated with hypothalamically driven increases in blood cortisol, norepinephrine, and sex steroid metabolite levels. This may contribute to the development of mesocortical sensitization to alcohol. Furthermore, chronic alcohol exposure is associated with systemic dysregulation of the hypothalamic pituitary adrenal axis, sympathetic adrenal medullary system, and sex steroid systems. This dysregulation appears to manifest as neuroendocrine tolerance. In this review, we first summarize the literature suggesting that alcohol-induced alterations in these hypothalamic systems influence craving and contribute to the development of AUDs. We note that for women, the effects of alcohol on these neuroendocrine stress regulation systems may be influenced by the rhythmic variations of hormones and steroids across the menstrual cycle. Second, we discuss how changes in these systems may indicate progression of AUDs and increased risk of relapse in both sexes. Specifically, neuroendocrine tolerance may contribute to mesocortical sensitization, which in turn may lead to decreased prefrontal inhibitory control of the dopaminergic reward and hypothalamic stress systems. Thus, pharmacological strategies that counteract alcohol-associated changes in hypothalamic and extrahypothalamic stress regulation pathways may slow the development and progression of AUDs. PMID:27254089

  7. Minority Adolescent Stress and Coping

    ERIC Educational Resources Information Center

    Gonzales, Nancy A.; George, Preethy E.; Fernandez, Aida Cristina; Huerta, Violeta L.

    2005-01-01

    Many of the stressful life events and daily hassles of adolescence are similar for youths despite differences in cultural background or place of residence. However, adolescents from diverse cultural groups often encounter unique challenges that arise from the particular cultural-ecological niches they inhabit by virtue of their ethnic group…

  8. Teaching L2 Spanish Stress

    ERIC Educational Resources Information Center

    Saalfeld, Anita K.

    2012-01-01

    The present study investigated the effects of training on the perception of Spanish stress, an important feature in the Spanish verbal morphology system. Participants were two intact classes of native English speakers enrolled in a six-week session of second-semester Spanish, as well as native English and native Spanish control groups. During the…

  9. Microelectromechanical systems contact stress sensor

    DOEpatents

    Kotovsky, Jack

    2007-12-25

    A microelectromechanical systems stress sensor comprising a microelectromechanical systems silicon body. A recess is formed in the silicon body. A silicon element extends into the recess. The silicon element has limited freedom of movement within the recess. An electrical circuit in the silicon element includes a piezoresistor material that allows for sensing changes in resistance that is proportional to bending of the silicon element.

  10. Women Religious Leaders and Stress.

    ERIC Educational Resources Information Center

    Rayburn, Carole A.; And Others

    This study examined stress, strain, and coping mechanisms in women religious leaders. Subjects were nuns (N=51), Reform women rabbis (N=45), Episcopal women priests (N=32), United Methodist clergywomen (N=45) and Presbyterian clergywomen (N=45), matched for age and years on the job and pulpit assignments. All subjects were given the Osipow and…

  11. Workers' Compensation and Teacher Stress.

    ERIC Educational Resources Information Center

    Nisbet, Michael K.

    1999-01-01

    Examines the Workers' Compensation system and teacher stress to determine if a burned-out teacher should be eligible for Workers' Compensation benefits. Concludes that although most states do not allow Workers' Compensation benefits to burned-out teachers, compensation should be granted because the injuries are real and work-related. (Contains 48…

  12. Occupational stress and illness incidence.

    PubMed

    Hoiberg, A

    1982-06-01

    This study examined hospitalization rates for 10 stress-related illnesses among Navy occupational groups during four phases of a 30-year career and identified possible reasons for differences in health risks among occupations and career phases. Results of this longitudinal study, which covered 11 years and included an initial population of 184,122 male Navy enlisted Caucasians, showed that men assigned to Hospital Corpsman and Mess Management Specialist (culinary work) categories had the highest health risks for stress-related illness during nearly all phases or decades of a Navy career. Other groups with elevated hospitalization rates included Construction/Manufacturing, Deck, Ordnance, and Engineering/Hull, whereas the lowest rates were observed for Miscellaneous/Technical, Electronics, and Administrative/Clerical. The highest hospitalization rates for stress-related diseases were evidenced during the third decade. Job stress scores were computed from ratings of environmental characteristics, occupational stressors and career considerations; high scores on these dimensions tended to be associated with increased illness. Implications of these results for prevention programs are discussed. PMID:7097375

  13. 75 FR 51292 - Before Commissioners: Ruth Y. Goldway, Chairman; Tony L. Hammond, Vice Chairman; Mark Acton; Dan...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-19

    ... From the Federal Register Online via the Government Publishing Office POSTAL REGULATORY COMMISSION Before Commissioners: Ruth Y. Goldway, Chairman; Tony L. Hammond, Vice Chairman; Mark Acton; Dan G. Blair; and Nanci E. Langley; Competitive Product Prices; Global Expedited Package Services 3...

  14. Comparison of cardioprotective effects using ramipril and DanShen for the treatment of acute myocardial infarction in rats.

    PubMed

    Ji, XinYan; Tan, Benny K-H; Zhu, Yi Chun; Linz, Wolfgang; Zhu, Yi Zhun

    2003-08-01

    In the present study, we compared cardioprotective effects of DanShen (an extract from Salvia miltiorrhiza) and the angiotensin-converting enzyme inhibitor, ramipril, in rats. With both treatment regimens, DanShen- and ramipril similar effects were observed: (1) a higher survival rate, (2) a significant reduction of infarct size, (3) significantly lower ratios of heart weight to the body weight as well as the left and right ventricular weights to body weight. DanShen showed some unique effects in the following aspects: (1) higher activities of antioxidant defense enzymes such as superoxide dismutase (SOD), catalase (CAT), glutatione perioxidase (GSH-Px) and glutathione S-transferase (GST) in the liver of rats with acute myocardial infarction (AMI), (2) lower myocardial and hepatic TBARS values; (3) augmented VEGF mRNA expressions in the non-ischemic parts of rat hearts with AMI. These results were consistent with the findings of a slight increase in myocardial capillary density and the special distribution pattern of coronary blood vessels in DanShen-treated rats. PMID:12850502

  15. Hémophilie: état des lieux dans un service de pédiatrie dans la région de l'oriental du Maroc

    PubMed Central

    Benajiba, Noufissa; Boussaadni, Yousra EL; Aljabri, Mohammed; Bentata, Yassamine; Amrani, Rim; Rkain, Maria

    2014-01-01

    Pour les pays en voie de développement, l'hémophilie continue d’être une maladie de conséquence médicale et sociale désastreuse. Le but de ce travail est d'analyser le suivi d'une cohorte de patients hémophiles. Patients et méthodes: étude prospective étalée sur deux années et menée au centre référent d'hémophilie dans la région de l'orient du Maroc. Ont été inclus tous les patients présentant une hémophilie confirmée et âgé de moins de 18 ans. Résultats: sur 16 hémophiles, Quinze patients présentait une hémophilie A, l’âge moyen des patients était de 6,18 ans, la forme sévère, représentait 20,7%, la forme modérée: 33,3% et la forme mineure: 40%. Les circonstances de découverte étaient post circoncisionnelle chez 53,3% des patients, 20,7% post traumatique, 20% à l’âge de la marche; la durée d’évolution variait entre 2 mois et 10 ans. L'hémarthrose a été décrite au niveau des genoux, coudes et chevilles, avec une moyenne allant de 2 à 5 fois par an; l'arthropathie a été remarquée dans 33,3%. Le bilan immunologique a révélé des facteurs circulant inhibant chez deux patients. Le traitement était à base d'antalgiques, de plasma frais congelé. L'administration de facteurs VIII recombinés a été instaurée chez 40,6% des patients (plus de 90% des formes modérées et graves), grâce au programme national de prise en charge des hémophiles. Le décès était noté dans un seul cas lié à une hémorragie cérébrale. Conclusion: Nous insistons sur l'intérêt du programme national de prise en charge des hémophiles dernièrement instauré qui pourrait améliorer les conditions de vie de ces enfants. PMID:25404986

  16. Laser induced surface stress on water droplets.

    PubMed

    Wang, Neng; Lin, Zhifang; Ng, Jack

    2014-10-01

    Laser induced stress on spherical water droplets is studied. At mechanical equilibrium, the body stress vanishes therefore we consider only the surface stress. The surface stress on sub-wavelength droplets is slightly weaker along the light propagation direction. For larger droplets, due to their light focusing effect, the forward stress is significantly enhanced. For a particle roughly 3 micron in radius, when it is excited at whispering gallery mode with Q ∼ 10⁴ by a 1 Watt Gaussian beam, the stress can be enhanced by two orders of magnitude, and can be comparable with the Laplace pressure. PMID:25321955

  17. Reducing stress on a college campus.

    PubMed

    Klainberg, Marilyn; Ewing, Bonnie; Ryan, Marybeth

    A variety of forces, internal and external, often impact students who are experiencing life on a college campus; these forces can lead to feelings of increased pressure and stress. To combat the negative effects of stress, faculty and administrators at a mid-size, suburban university collaborated to help students decrease their stress and assist them in attaining and maintaining a healthy lifestyle. A Stress Reduction Room (SRR) was designed, implemented, and evaluated with the goal of decreasing stress in this student population. The function of the SRR, benefits, and implications identified from the stress reduction campus initiative, are described in this paper. PMID:21510150

  18. The Golgi complex in stress and death

    PubMed Central

    Machamer, Carolyn E.

    2015-01-01

    The Golgi complex is a central organelle of the secretory pathway where sorting and processing of cargo occurs. While Golgi structure is important for the efficient processing of secretory cargo, the unusual organization suggests additional potential functions. The Golgi is disassembled after various cellular stresses, and we hypothesize that Golgi disassembly activates a stress signaling pathway. This pathway would function to correct the stress if possible, with irreparable stress resulting in apoptosis. Neurons appear to be particularly sensitive to Golgi stress; early disassembly of the organelle correlates with many neurodegenerative diseases. Here, Golgi stress and potential signaling pathways to the nucleus are reviewed. PMID:26594142

  19. Pediatric stress fractures: a pictorial essay

    PubMed Central

    Shelat, Nirav H.; El-Khoury, Georges Y.

    2016-01-01

    More children are participating in organized and recreational athletics at a younger age. It has been well documented that increased athletic specialization and year-round activities have resulted in higher incidences of overuse injuries, including stress fractures and stress reactions. Initially, stress fractures can be radiographically occult. Continued stress on the injured bone or cartilage can lead to progressive radiographic changes. Because of the prevalence of these injuries, both orthopedic surgeons and radiologists should be aware of the radiographic and magnetic resonance imaging (MRI) features of common stress fractures in children. This article reviews frequently encountered stress fractures involving various bones in the pediatric population. PMID:27528851

  20. The Golgi complex in stress and death.

    PubMed

    Machamer, Carolyn E

    2015-01-01

    The Golgi complex is a central organelle of the secretory pathway where sorting and processing of cargo occurs. While Golgi structure is important for the efficient processing of secretory cargo, the unusual organization suggests additional potential functions. The Golgi is disassembled after various cellular stresses, and we hypothesize that Golgi disassembly activates a stress signaling pathway. This pathway would function to correct the stress if possible, with irreparable stress resulting in apoptosis. Neurons appear to be particularly sensitive to Golgi stress; early disassembly of the organelle correlates with many neurodegenerative diseases. Here, Golgi stress and potential signaling pathways to the nucleus are reviewed. PMID:26594142