Fracture transmissivity as a function of normal and shear stress: first results in Opalinus Clay

International Nuclear Information System (INIS)

Cuss, R.J.; Milodowski, A.; Noy, D.J.; Harrington, J.F.

2010-01-01

Document available in extended abstract form only. Rock-mass failure around openings is usually observed in the form of a highly complex fracture network (EDZ), which is heterogeneous in distribution around a circular tunnel opening because of the heterogeneous stress distribution. The orientation of stress with respect to the fracture network is known to be important. The complex heterogeneous stress trajectory and heterogeneous fracture network results in a broad range of stresses and stress directions acting on the open fracture network. During the open stage of a repository, stress will slowly alter as shear movements occur along the fractures, as well as other time-dependent phenomena. As the repository is back filled, the stress field is further altered as the backfill settles and changes volume because of re-saturation. Therefore, a complex and wide ranging stress regime and stress history will result. In a purely mechanical sense, fracture transmissivity is a function of normal stress, shear stress, and fracture aperture. The Selfrac test from Mont Terri showed the change in transmissivity with effective normal stress. This work showed that fracture transmissivity decreased with increasing normal load and that an effective normal stress of 2.5 MPa is sufficient to yield a transmissivity similar to that seen in intact Opalinus clay (OPA). Therefore fracture closure because of normal stresses has been proven to be a quite efficient mechanism in OPA. A new shear rig was designed to investigate the detail of fracture transmissivity in OPA. The experimental configuration uses two prepared blocks that are 60 x 60 mm in size and approximately 20 mm thick. The first test sample had machine ground surfaces in contact with each other, with pore fluid being delivered through the centre of the top block directly to the fracture surface. The experimental programme included two distinct stages. In the first normal load was altered to investigate fracture transmissivity

The Lcn2-engineered HEK-293 cells show senescence under stressful condition

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Bahareh Bahmani

2015-05-01

Full Text Available Objective(s: Lipocalin2 (Lcn2 gene is highly expressed in response to various types of cellular stresses. The precise role of Lcn2 has not been fully understood yet. However, it plays a key role in controlling vital cellular processes such as proliferation, apoptosis and metabolism. Recently it was shown that Lcn2 decreases senescence and increases proliferation of mesenchymal stem cells (MSC with finite life span under either normal or oxidative stress conditions. However, Lcn2 effects on immortal cell line with infinite proliferation are not defined completely.  Materials and Material and Methods: HEK-293 cells were transfected with recombinant pcDNA3.1 containing Lcn2 fragment (pcDNA3.1-Lcn2. Expression of lipocalin2 in transfected cells was evaluated by RT-PCR, real time RT-PCR, and ELISA. Different cell groups were treated with H2O2 and WST-1 assay was performed to determine their proliferation rate. Senescence was studied by β-galactosidase and gimsa staining methods as well as evaluation of the expression of senescence-related genes by real time RT-PCR. Results: Lcn2 increased cell proliferation under normal culture condition, while the proliferation slightly decreased under oxidative stress.  This decrease was further found to be attributed to senescence. Conclusion: Our findings indicated that under harmful conditions, Lcn2 gene is responsible for the regulation of cell survival through senescence.

Comparison between the results of stress relaxation - and creep tests in a stainless steel 316 at 8000C

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Miranda, P.E.V. de.

1978-07-01

A sequence of stress relaxation tests from the same initial stress showed an estabilization of the relaxed fraction of stress of a 316 stainless steel at 800 0 C. This represents the exhaustion of the deformation process of the material at this temperature. Results from the relaxation tests were obtained by utilizing a recently proposed model. The slope in from the log epsilon sup(.) x logσ/E curve obtained by relaxation (n = 6,80) closely matched that determined by creep tests (n = 6,50). This presents a possibility of determined by stress relaxation of the parameters usually calculated by creep. (Author) [pt

Unconscious fearful priming followed by a psychosocial stress test results in higher cortisol levels.

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Hänsel, Alexander; von Känel, Roland

2013-10-01

Human perception of stress includes an automatic pathway that processes subliminal presented stimuli below the threshold of conscious awareness. Subliminal stimuli can therefore activate the physiologic stress system. Unconscious emotional signals were shown to significantly moderate reactions and responses to subsequent stimuli, an effect called 'priming'. We hypothesized that subliminal presentation of a fearful signal during the Stroop task compared with an emotionally neutral one will prime stress reactivity in a subsequently applied psychosocial stress task, thereby yielding a significant increase in salivary cortisol. Half of 36 participants were repeatedly presented either a fearful face or a neutral one. After this, all underwent a psychosocial stress task. The fearful group showed a significant increase in cortisol levels (p = 0.022). This change was not affected by sex, age and body mass index, and it also did not change when taking resting cortisol levels into account. Post-hoc analyses showed that the increase in cortisol in the fearful group started immediately after the psychosocial stress test. Hence, subliminal exposure to a fearful signal in combination with the Stroop and followed by a psychosocial stress test leads to an increase in stress reactivity. Copyright © 2012 John Wiley & Sons, Ltd.

Photosystem I shows a higher tolerance to sorbitol-induced osmotic stress than photosystem II in the intertidal macro-algae Ulva prolifera (Chlorophyta).

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Gao, Shan; Zheng, Zhenbing; Gu, Wenhui; Xie, Xiujun; Huan, Li; Pan, Guanghua; Wang, Guangce

2014-10-01

The photosynthetic performance of the desiccation-tolerant, intertidal macro-algae Ulva prolifera was significantly affected by sorbitol-induced osmotic stress. Our results showed that photosynthetic activity decreased significantly with increases in sorbitol concentration. Although the partial activity of both photosystem I (PS I) and photosystem II (PS II) was able to recover after 30 min of rehydration, the activity of PS II decreased more rapidly than PS I. At 4 M sorbitol concentration, the activity of PS II was almost 0 while that of PS I was still at about one third of normal levels. Following prolonged treatment with 1 and 2 M sorbitol, the activity of PS I and PS II decreased slowly, suggesting that the effects of moderate concentrations of sorbitol on PS I and PS II were gradual. Interestingly, an increase in non-photochemical quenching occurred under these conditions in response to moderate osmotic stress, whereas it declined significantly under severe osmotic stress. These results suggest that photoprotection in U. prolifera could also be induced by moderate osmotic stress. In addition, the oxidation of PS I was significantly affected by osmotic stress. P700(+) in the thalli treated with high concentrations of sorbitol could still be reduced, as PS II was inhibited by 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), but it could not be fully oxidized. This observation may be caused by the higher quantum yield of non-photochemical energy dissipation in PS I due to acceptor-side limitation (Y(NA)) during rehydration in seawater containing DCMU. © 2014 Scandinavian Plant Physiology Society.

[Stress and Burnout Risk in Nursery School Teachers: Results from a Survey].

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Jungbauer, J; Ehlen, S

2015-06-01

This article presents results from a study of 834 nursery school teachers in Germany, investigating working conditions, stress, and stress-related health problems. In order to evaluate the extent of mental and psychosomatic troubles, as well as the risk of burnout, we used the standardised questionnaire "Burnout Screening Scales" (BOSS I). Data analysis yielded a high percentage of nursery school teachers who reported a remarkably high stress level; nearly 20% can be considered as a high-risk group for burnout. Poor staff conditions in many nurseries turned out to be the crucial stress source, along with large groups, insufficient teacher-child ratio, time pressure and multitasking. In the concluding discussion of the study results, we consider possible measures to reduce stress and to improve working conditions for nursery school teachers. © Georg Thieme Verlag KG Stuttgart · New York.

Stressful life events and Graves' disease: Results of a case control study

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Pintor, A.B.; Barrenechea, E.A.; Laureta, E.G.; Ligon, R.A.

2003-01-01

Prolonged worry has generally been acknowledged as one of the main precipitating factors of the onset of Graves' disease. A review of literature reveals that emotional stresses of considerable severity precede the onset of hyperthyroidism in about 90% of cases. However, not everyone subscribes to the Stress/Graves' disease hypothesis. Attempts to resolve this issue have tended to focus on whether a correlation can be shown between the magnitude of antecedent life events and the disease. Hence the main objective of the present study was to identify the possible association between stressful life events and Graves' disease. This paper presents the results of a case-control study, involving patents and subjects from the Veterans Memorial Medical Centre of Manila. A total of 224 patients of Graves' disease, newly or previously diagnosed, representing the 'patient's' arm were interviewed. All patients were questioned regarding various stresses, which greatly affected their life style spanning over a 12-month period prior to the onset of the disease. Simultaneously, 224 control subjects were also interviewed, and their stresses spanning over a similar period preceding the dates of interviews were recorded in quantifiable terms. Different stresses were given different intensity scores based on a social readjustment scale taking into consideration the life situations, emotions and diseases. In cases of multiple stresses, intensity scores were added to obtain the total stress intensity. Results were expressed as mean, standard deviation, median, frequency and percent distribution. Scatter plot was also constructed for intensity of stressful life events. To determine association of different factors with Graves' disease, Students t-test and chi-square tests were applied to the data. Odds ratio (OR) was also computed to determine risk attributed to each factor. Since there was significant difference in gender distribution between the patients and controls, stratified Mantel

A 67-Item Stress Resilience item bank showing high content validity was developed in a psychosomatic sample.

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Obbarius, Nina; Fischer, Felix; Obbarius, Alexander; Nolte, Sandra; Liegl, Gregor; Rose, Matthias

2018-04-10

To develop the first item bank to measure Stress Resilience (SR) in clinical populations. Qualitative item development resulted in an initial pool of 131 items covering a broad theoretical SR concept. These items were tested in n=521 patients at a psychosomatic outpatient clinic. Exploratory and Confirmatory Factor Analysis (CFA), as well as other state-of-the-art item analyses and IRT were used for item evaluation and calibration of the final item bank. Out of the initial item pool of 131 items, we excluded 64 items (54 factor loading .3, 2 non-discriminative Item Response Curves, 4 Differential Item Functioning). The final set of 67 items indicated sufficient model fit in CFA and IRT analyses. Additionally, a 10-item short form with high measurement precision (SE≤.32 in a theta range between -1.8 and +1.5) was derived. Both the SR item bank and the SR short form were highly correlated with an existing static legacy tool (Connor-Davidson Resilience Scale). The final SR item bank and 10-item short form showed good psychometric properties. When further validated, they will be ready to be used within a framework of Computer-Adaptive Tests for a comprehensive assessment of the Stress-Construct. Copyright © 2018. Published by Elsevier Inc.

Physical Stress Echocardiography: Prediction of Mortality and Cardiac Events in Patients with Exercise Test showing Ischemia

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Ana Carla Pereira de Araujo

2014-11-01

Full Text Available Background: Studies have demonstrated the diagnostic accuracy and prognostic value of physical stress echocardiography in coronary artery disease. However, the prediction of mortality and major cardiac events in patients with exercise test positive for myocardial ischemia is limited. Objective: To evaluate the effectiveness of physical stress echocardiography in the prediction of mortality and major cardiac events in patients with exercise test positive for myocardial ischemia. Methods: This is a retrospective cohort in which 866 consecutive patients with exercise test positive for myocardial ischemia, and who underwent physical stress echocardiography were studied. Patients were divided into two groups: with physical stress echocardiography negative (G1 or positive (G2 for myocardial ischemia. The endpoints analyzed were all-cause mortality and major cardiac events, defined as cardiac death and non-fatal acute myocardial infarction. Results: G2 comprised 205 patients (23.7%. During the mean 85.6 ± 15.0-month follow-up, there were 26 deaths, of which six were cardiac deaths, and 25 non-fatal myocardial infarction cases. The independent predictors of mortality were: age, diabetes mellitus, and positive physical stress echocardiography (hazard ratio: 2.69; 95% confidence interval: 1.20 - 6.01; p = 0.016. The independent predictors of major cardiac events were: age, previous coronary artery disease, positive physical stress echocardiography (hazard ratio: 2.75; 95% confidence interval: 1.15 - 6.53; p = 0.022 and absence of a 10% increase in ejection fraction. All-cause mortality and the incidence of major cardiac events were significantly higher in G2 (p < 0. 001 and p = 0.001, respectively. Conclusion: Physical stress echocardiography provides additional prognostic information in patients with exercise test positive for myocardial ischemia.

Triaxial Wetting Test on Rockfill Materials under Stress Combination Conditions of Spherical Stress p and Deviatoric Stress q

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Yan-yi Zhang

2018-01-01

Full Text Available A GCTS medium-sized triaxial apparatus is used to conduct a single-line method wetting test on three kinds of rockfill materials of different mother rocks such as mixture of sandstone and slate, and dolomite and granite, and the test stress conditions is the combination of spherical stress p and deviatoric stress q. The test results show that (1 for wetting shear strain, the effects of spherical stress p and deviatoric stress q are equivalent, and wetting shear strain and deviatoric stress q show the power function relationship preferably. (2 For wetting volumetric strain, the effect of deviatoric stress q can be neglected because it is extremely insignificant, and spherical stress p is the main influencing factor and shows the power function relationship preferably. (3 The wetting strains decrease significantly with the increase in initial water content and sample density generally, but the excessively high dry density will increase the wetting deformation. Also, the wetting strains will decrease with the increase in the saturated uniaxial compressive strength and average softening coefficient of the mother rock. Based on the test results, a wetting strain model is proposed for rockfill materials. The verification results indicate that the model satisfactorily reflects the development law of wetting deformation.

Posttraumatic Stress Disorder Patients and Results of Violent Behavior

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Taner Oznur

2014-08-01

Full Text Available AIM: High levels of anger and aggression in post-traumatic stress disorder lead to unfavorable social, legal, physical and economic results to family members and the other social layers as much as patients. In this study, it is aimed to investigate the relation between both alcohol-cigarette consumption ratios and anger levels, characteristics of aggressive behaviors and the judicial outcome in cases diagnosed post-traumatic stress disorder due to armed conflict. METHODS: 38 cases diagnosed as post-traumatic stress disorder were included to the study. Pre- and post-traumatic alcohol/cigarette consumption amounts and aggressive behaviors are determined. Impact of Events Scale (Revised (IES-R was used for evaluating post-traumatic stress disorder symptom patterns and severity, Buss Perry Aggression Questionnaire was used for measuring anger and aggression levels, and Taylor and #8217;s Violence Rating Scale was used for evaluating the judicial outcome of aggression. RESULTS: 23 of cases (60.6% were married with children, 13 of cases (34.25 were single and 2 of cases (5.2% were divorced.18 of cases (47.4% were graduate. IES-R total score was 66,9 +/- 12,7, Buss Perry total score was 111,3 +/- 20,5, and Taylor and #8217;s Violence Rate was 2,5 +/- 1,0. When the pre- and post-traumatic aggressive behaviors were compared; physical violence to the partner was increased more than ten times, Physical and verbal violence to social individuals were increased more than four and seven times, respectively. And also it is observed that inflicting damage to property was increased 17 times, reckless driving was increased 11 times, and self-mutilation was increased 5 times. Alcohol consumption was determined as 0 (0 - 126 g/day for pre-trauma cases and 16.5 (0 - 294 g/day for post-trauma cases. Cigarette smoking was determined as 5 (0 and #8211; 40 cigarette/day for pre-trauma cases and 30 (0 -60 cigarette/day for post-trauma cases. CONCLUSION: Post

Work site stress management: national survey results.

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Fielding, J E

1989-12-01

The National Survey of Work Site Health Promotion Activities established baseline data on the frequency of nine types of health promotion activity at private work sites with more than 50 employees in the United States. Stress management activities were provided at 26.6% of work sites. Types of activities at those work sites with some stress management activity included group counseling (58.5%), individual counseling (39.3%), follow-up counseling (25.9%), special events (11.5%), providing information about stress (80.7%), providing a place to relax (64.8%), and making organizational changes to reduce employee stress (81.2%). Frequency of activities varied by industry type and by region of the country. Incidence of most types of activities did not increase as work site size increased, although the likelihood of having any of these activities did increase with work site size. Stress management activities were more likely to be present at work sites with a medical staff or health educator. An increase in output, productivity, or quality was the most frequently cited benefit (46.5%). Negative effects were reported at 2.6% of the work sites. Other health promotion activities found at the work sites surveyed included smoking cessation (61.8%), treatment and control of high blood pressure (36.7%), and weight control (34.7%). Employee Assistance Programs were responsible for stress management at 62% of the work sites with an Employee Assistance Program.

Stress and burnout in psychiatric professionals when starting to use dialectical behavioural therapy in the work with young self-harming women showing borderline personality symptoms.

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Perseius, K-I; Kåver, A; Ekdahl, S; Asberg, M; Samuelsson, M

2007-10-01

The aim of the study was to investigate how starting to use dialectical behavioural therapy (DBT) in the work with young self-harming women showing symptoms of borderline personality disorder affected the psychiatric professionals (n = 22) experience of occupational stress and levels of professional burnout. The study was carried out in relation to an 18-month clinical psychiatric development project, and used a mix of quantitative and qualitative research methods [a burnout inventory, the Maslach burnout inventory-General Survey (MBI-GS), free format questionnaires and group interviews]. The result confirms previous reports that psychiatric health professionals experience treatment of self-harming patients as very stressful. DBT was seen as stressful in terms of learning demands, but decreased the experience of stress in the actual treatment of the patients. The teamwork and supervision were felt to be supportive, as was one particular facet of DBT, namely mindfulness training which some therapists felt also improved their handling of other work stressors not related to DBT. The inventory for professional burnout, the MBI-GS, showed no significant changes over the 18-month period, although there was a tendency for increased burnout levels at the 6-month assessment, which had returned to baseline levels at 18 months.

Drought Stress Results in a Compartment-Specific Restructuring of the Rice Root-Associated Microbiomes

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Christian Santos-Medellín

2017-07-01

Full Text Available Plant roots support complex microbial communities that can influence plant growth, nutrition, and health. While extensive characterizations of the composition and spatial compartmentalization of these communities have been performed in different plant species, there is relatively little known about the impact of abiotic stresses on the root microbiota. Here, we have used rice as a model to explore the responses of root microbiomes to drought stress. Using four distinct genotypes, grown in soils from three different fields, we tracked the drought-induced changes in microbial composition in the rhizosphere (the soil immediately surrounding the root, the endosphere (the root interior, and unplanted soils. Drought significantly altered the overall bacterial and fungal compositions of all three communities, with the endosphere and rhizosphere compartments showing the greatest divergence from well-watered controls. The overall response of the bacterial microbiota to drought stress was taxonomically consistent across soils and cultivars and was primarily driven by an enrichment of multiple Actinobacteria and Chloroflexi, as well as a depletion of several Acidobacteria and Deltaproteobacteria. While there was some overlap in the changes observed in the rhizosphere and endosphere communities, several drought-responsive taxa were compartment specific, a pattern likely arising from preexisting compositional differences, as well as plant-mediated processes affecting individual compartments. These results reveal that drought stress, in addition to its well-characterized effects on plant physiology, also results in restructuring of root microbial communities and suggest the possibility that constituents of the altered plant microbiota might contribute to plant survival under extreme environmental conditions.

Perturbations in carotenoid and porphyrin status result in differential photooxidative stress signaling and antioxidant responses.

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Park, Joon-Heum; Jung, Sunyo

2018-02-12

We examined differential photooxidative stress signaling and antioxidant responses in rice plants treated with norflurazon (NF) and oxyfluorfen (OF), which are inhibitors of carotenoid and porphyrin biosynthesis, respectively. Plants treated with OF markedly increased levels of cellular leakage and malondialdehyde, compared with NF-treated plants, showing that OF plants suffered greater oxidative damage with respect to membrane integrity. The enhanced production of H 2 O 2 in response to OF, but not NF, indicates the important role of H 2 O 2 in activation of photooxidative stress signaling in OF plants. In response to NF and OF, the increased levels of free salicylic acid as well as maintenance of the redox ratio of ascorbate and glutathione pools to a certain level are considered to be crucial factors in the protection against photooxidation. Plants treated with OF greatly up-regulated catalase (CAT) activity and Cat transcript levels, compared with NF-treated plants. Interestingly, NF plants showed no noticeable increase in oxidative metabolism, although they did show considerable increases in ascorbate peroxidase (APX) and peroxidase activities and transcript levels of APX, as in OF plants. Our results suggest that perturbations in carotenoid and porphyrin status by NF and OF can be sensed by differential photooxidative stress signaling, such as that involving H 2 O 2 , redox state of ascorbate and glutathione, and salicylic acid, which may be responsible for at least part of the induction of ROS-scavenging enzymes. Copyright © 2018 Elsevier Inc. All rights reserved.

Depression and oxidative stress: results from a meta-analysis of observational studies.

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Palta, Priya; Samuel, Laura J; Miller, Edgar R; Szanton, Sarah L

2014-01-01

To perform a systematic review and meta-analysis that quantitatively tests and summarizes the hypothesis that depression results in elevated oxidative stress and lower antioxidant levels. We performed a meta-analysis of studies that reported an association between depression and oxidative stress and/or antioxidant status markers. PubMed and EMBASE databases were searched for articles published from January 1980 through December 2012. A random-effects model, weighted by inverse variance, was performed to pool standard deviation (Cohen's d) effect size estimates across studies for oxidative stress and antioxidant status measures, separately. Twenty-three studies with 4980 participants were included in the meta-analysis. Depression was most commonly measured using the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria. A Cohen's d effect size of 0.55 (95% confidence interval = 0.47-0.63) was found for the association between depression and oxidative stress, indicating a roughly 0.55 of 1-standard-deviation increase in oxidative stress among individuals with depression compared with those without depression. The results of the studies displayed significant heterogeneity (I(2) = 80.0%, p < .001). A statistically significant effect was also observed for the association between depression and antioxidant status markers (Cohen's d = -0.24, 95% confidence interval = -0.33 to -0.15). This meta-analysis observed an association between depression and oxidative stress and antioxidant status across many different studies. Differences in measures of depression and markers of oxidative stress and antioxidant status markers could account for the observed heterogeneity. These findings suggest that well-established associations between depression and poor heath outcomes may be mediated by high oxidative stress.

Long-term changes in cognitive bias and coping response as a result of chronic unpredictable stress during adolescence.

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Chaby, Lauren E; Cavigelli, Sonia A; White, Amanda; Wang, Kayllie; Braithwaite, Victoria A

2013-01-01

Animals that experience adverse events in early life often have life-long changes to their physiology and behavior. Long-term effects of stress during early life have been studied extensively, but less attention has been given to the consequences of negative experiences solely during the adolescent phase. Adolescence is a particularly sensitive period of life when regulation of the glucocorticoid "stress" hormone response matures and specific regions in the brain undergo considerable change. Aversive experiences during this time might, therefore, be expected to generate long-term consequences for the adult phenotype. Here we investigated the long-term effects of exposure to chronic unpredictable stress during adolescence on adult decision-making, coping response, cognitive bias, and exploratory behavior in rats. Rats exposed to chronic unpredictable stress (e.g., isolation, crowding, cage tilt) were compared to control animals that were maintained in standard, predictable conditions throughout development. Unpredictable stress during adolescence resulted in a suite of long-term behavioral and cognitive changes including a negative cognitive bias [F (1, 12) = 5.000, P chronic stress during adolescence also caused a short-term increase in boldness behaviors; in a novel object test 15 days after the last stressor, animals exposed to chronic unpredictable stress had decreased latencies to leave a familiar shelter and approach a novel object [T (1, 14) = 2.240, P = 0.04; T (1, 14) = 2.419, P = 0.03, respectively]. The results showed that stress during adolescence has long-term impacts on behavior and cognition that affect the interpretation of ambiguous stimuli, behavioral response to adverse events, and how animals make decisions.

Mechanical Stress Results in Immediate Accumulation of Glucosinolates in Fresh-Cut Cabbage

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Tomaž Požrl

2015-01-01

Full Text Available The intensity of mechanical stress and the temperature significantly affect the levels of individual and total glucosinolates in shredded white cabbage (cv. Galaxy. Mild processing (shredding to 2 mm thickness at 8°C resulted in the accumulation of glucosinolates (40% increase in comparison with unshredded cabbage, which was already seen 5 min after the mechanical stress. Severe processing (shredding to 0.5 mm thickness at 20°C, however, resulted in an initial 50% decrease in glucosinolates. The glucosinolates accumulated in all of the cabbage samples 30 min from processing, resulting in higher levels than in unshredded cabbage, except for the severe processing at 20°C where the increase was not sufficient to compensate for the initial loss. Glucobrassicin and neoglucobrassicin were the major glucosinolates identified in the cabbage samples. Mechanical stress resulted in an increase in the relative proportion of glucobrassicin and in a decrease in neoglucobrassicin.

Psychological and Work Stress Assessment of Patients following Angioplasty or Heart Surgery: Results of 1-year Follow-up Study.

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Fiabane, Elena; Giorgi, Ines; Candura, Stefano M; Argentero, Piergiorgio

2015-12-01

The aim of this study was to explore changes in subjective psychological health and perceived work stress among patients who returned to work (RTW) after a multidisciplinary cardiac rehabilitation (CR) following cardiac interventions. A total of 108 patients were evaluated at the beginning of their CR, at 6 and 12 months after discharge. Self-report questionnaires were used to assess depression, anxiety, illness perception and work stress at each time stage. Results showed reports of depressive symptoms significantly decreased (p work stress after their RTW. Patients' psychological health and work stress need to be assessed during the CR and should be also carefully monitored after the RTW in order to identify patients' psychological and work-related barriers and facilitate a safe and successful work reintegration. Copyright © 2014 John Wiley & Sons, Ltd.

High-anxious individuals show increased chronic stress burden, decreased protective immunity, and increased cancer progression in a mouse model of squamous cell carcinoma.

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Firdaus S Dhabhar

Full Text Available In spite of widespread anecdotal and scientific evidence much remains to be understood about the long-suspected connection between psychological factors and susceptibility to cancer. The skin is the most common site of cancer, accounting for nearly half of all cancers in the US, with approximately 2-3 million cases of non-melanoma cancers occurring each year worldwide. We hypothesized that a high-anxious, stress-prone behavioral phenotype would result in a higher chronic stress burden, lower protective-immunity, and increased progression of the immuno-responsive skin cancer, squamous cell carcinoma. SKH1 mice were phenotyped as high- or low-anxious at baseline, and subsequently exposed to ultraviolet-B light (1 minimal erythemal dose (MED, 3 times/week, 10-weeks. The significant strengths of this cancer model are that it uses a normal, immunocompetent, outbred strain, without surgery/injection of exogenous tumor cells/cell lines, and produces lesions that resemble human tumors. Tumors were counted weekly (primary outcome, and tissues collected during early and late phases of tumor development. Chemokine/cytokine gene-expression was quantified by PCR, tumor-infiltrating helper (Th, cytolytic (CTL, and regulatory (Treg T cells by immunohistochemistry, lymph node T and B cells by flow cytometry, adrenal and plasma corticosterone and tissue vascular-endothelial-growth-factor (VEGF by ELISA. High-anxious mice showed a higher tumor burden during all phases of tumor development. They also showed: higher corticosterone levels (indicating greater chronic stress burden, increased CCL22 expression and Treg infiltration (increased tumor-recruited immuno-suppression, lower CTACK/CCL27, IL-12, and IFN-γ gene-expression and lower numbers of tumor infiltrating Th and CTLs (suppressed protective immunity, and higher VEGF concentrations (increased tumor angiogenesis/invasion/metastasis. These results suggest that the deleterious effects of high trait anxiety

Acute posttraumatic stress symptoms and depression after exposure to the 2005 Saskatchewan Centennial Air Show disaster: prevalence and predictors.

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Taylor, Steven; Asmundson, Gordon J G; Carleton, R Nicholas; Brundin, Peter

2007-01-01

The purpose of this study was to determine the prevalence of acute distress-that is, clinically significant posttraumatic stress symptoms (PTSS) and depression-and to identify predictors of each in a sample of people who witnessed a fatal aircraft collision at the 2005 Saskatchewan Centennial Air Show. Air Show attendees (N = 157) were recruited by advertisements in the local media and completed an Internet-administered battery of questionnaires. Based on previously established cut-offs, 22 percent respondents had clinically significant PTSS and 24 percent had clinically significant depressive symptoms. Clinically significant symptoms were associated with posttrauma impairment in social and occupational functioning. Acute distress was associated with several variables, including aspects of Air Show trauma exposure, severity of prior trauma exposure, low posttrauma social support (ie, negative responses by others), indices of poor coping (eg, intolerance of uncertainty, rumination about the trauma), and elevated scores on anxiety sensitivity, the personality trait of absorption, and dissociative tendencies. Results suggest that clinically significant acute distress is common in the aftermath of witnessed trauma. The statistical predictors (correlates) of acute distress were generally consistent with the results of studies of other forms of trauma. People with elevated scores on theoretical vulnerability factors (eg, elevated anxiety sensitivity) were particularly likely to develop acute distress.

Specificity in mediated pathways by anxiety symptoms linking adolescent stress profiles to depressive symptoms: Results of a moderated mediation approach.

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Anyan, Frederick; Bizumic, Boris; Hjemdal, Odin

2018-03-01

We investigated the specificity in mediated pathways that separately link specific stress dimensions through anxiety to depressive symptoms and the protective utility of resilience. Thus, this study goes beyond lumping together potential mediating and moderating processes that can explain the relations between stress and (symptoms of) psychopathology and the buffering effect of resilience. Ghanaian adolescents between 13 and 17 years (female = 285; male = 244) completed the Adolescent Stress Questionnaire (ASQ), Spielberger State Anxiety Inventory (STAI), Short Mood Feeling Questionnaire (SMFQ) and the Resilience Scale for Adolescents (READ). Independent samples t-test, multivariate analysis of covariance with follow-up tests and moderated mediation analyses were performed. Evidences were found for specificity in the associations between dimensions of adolescent stressors and depressive symptoms independent of transient anxiety. Transient anxiety partly accounted for the indirect effects of eight stress dimensions on depressive symptoms. Except stress of school attendance and school/leisure conflict, resilience moderated the indirect effects of specific stress dimensions on depressive symptoms. Results suggested differences in how Ghanaian adolescents view the various stress dimensions, and mediated pathways associated with anxiety and depressive symptoms. Use of cross-sectional data does not show causal process and temporal changes over time. Findings support and clarify the specificity in the interrelations and mediated pathways among dimensions of adolescent stress, transient anxiety, and depressive symptoms. Conditional process analyses shows that resilience does not only buffer direct, but also indirect psychological adversities. Interventions for good mental health may focus on low resilience subgroups in specific stress dimensions while minimizing transient anxiety. Copyright © 2017 Elsevier B.V. All rights reserved.

Plant-Adapted Escherichia coli Show Increased Lettuce Colonizing Ability, Resistance to Oxidative Stress and Chemotactic Response

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Dublan, Maria de los Angeles; Ortiz-Marquez, Juan Cesar Federico; Lett, Lina; Curatti, Leonardo

2014-01-01

Background Escherichia coli is a widespread gut commensal and often a versatile pathogen of public health concern. E. coli are also frequently found in different environments and/or alternative secondary hosts, such as plant tissues. The lifestyle of E. coli in plants is poorly understood and has potential implications for food safety. Methods/Principal Findings This work shows that a human commensal strain of E. coli K12 readily colonizes lettuce seedlings and produces large microcolony-like cell aggregates in leaves, especially in young leaves, in proximity to the vascular tissue. Our observations strongly suggest that those cell aggregates arise from multiplication of single bacterial cells that reach those spots. We showed that E. coli isolated from colonized leaves progressively colonize lettuce seedlings to higher titers, suggesting a fast adaptation process. E. coli cells isolated from leaves presented a dramatic rise in tolerance to oxidative stress and became more chemotactic responsive towards lettuce leaf extracts. Mutant strains impaired in their chemotactic response were less efficient lettuce colonizers than the chemotactic isogenic strain. However, acclimation to oxidative stress and/or minimal medium alone failed to prime E. coli cells for enhanced lettuce colonization efficiency. Conclusion/Significance These findings help to understand the physiological adaptation during the alternative lifestyle of E. coli in/on plant tissues. PMID:25313845

Long-term changes in cognitive bias and coping response as a result of chronic unpredictable stress during adolescence

Directory of Open Access Journals (Sweden)

Lauren eChaby

2013-07-01

Full Text Available Animals that experience adverse events in early life often have life-long changes to their physiology and behavior. Long-term effects of stress during early life have been studied extensively, but less attention has been given to the consequences of negative experiences solely during the adolescent phase. Adolescence is a particularly sensitive period of life when regulation of the glucocorticoid stress hormone response matures and specific regions in the brain undergo considerable change. Aversive experiences during this time might, therefore, be expected to generate long-term consequences for the adult phenotype. Here we investigated the long-term effects of exposure to chronic unpredictable stress during adolescence on adult decision making, coping response, cognitive bias, and exploratory behavior in rats. Rats exposed to chronic unpredictable stress (e.g. isolation, crowding, cage tilt were compared to control animals that were maintained in standard, predictable conditions throughout development. Unpredictable stress during adolescence resulted in a suite of long-term behavioral and cognitive changes including a negative cognitive bias (F1,12 = 5.000, P < 0.05, altered coping response (T1,14 = 2.216, P = 0.04, and accelerated decision making (T1,14 = 3.245, P = 0.01. Exposure to chronic stress during adolescence also caused a short-term increase in boldness behaviors; in a novel object test 15 days after the last stressor, animals exposed to chronic unpredictable stress had decreased latencies to leave a familiar shelter and approach a novel object (T1,14 = 2.240, P = 0.04; T1,14 = 2.419, P = 0.03, respectively. The results showed that stress during adolescence has long-term impacts on behavior and cognition that affect the interpretation of ambiguous stimuli, behavioral response to adverse events, and how animals make decisions. Stress during adolescence also induced short-term changes in the way animals moved around a novel environment.

Initial Results from the New Stress Map of Texas Project

Science.gov (United States)

Lund Snee, J. E.; Zoback, M. D.

2015-12-01

Modern techniques for characterizing tectonic stress orientation and relative magnitude have been successfully used for more than 35 years. Nevertheless, large areas of North America lack high spatial resolution maps of stress orientation, magnitude, and faulting regime. In Texas, for example, data are foundational elements of attempts to characterize tectonic driving forces, understand hazards associated with induced seismicity, and optimize production of oil, gas, and geothermal resources. This year, we launched the Texas Stress Map project to characterize tectonic stress patterns at higher spatial resolution across Texas and nearby areas. Following a successful effort just completed in Oklahoma, we will evaluate borehole breakouts, drilling-induced tensile fractures, shear wave anisotropy, and earthquake data. The principal data source will be FMI (fullbore formation microimager), UBI (ultrasonic borehole imager), cross-dipole sonic, density, and caliper logs provided by private industry. Earthquake moment tensor solutions from the U.S. Geological Survey, Saint Louis University and other sources will also be used. Our initial focus is on the Permian Basin and Barnett Shale petroleum plays due to the availability of data, but we will expand our analysis across the state as the project progresses. In addition, we hope to eventually apply the higher spatial resolution data coverage to understanding tectonic and geodynamic characteristics of the southwestern United States and northeastern Mexico. Here we present early results from our work to constrain stress orientations and faulting regime in and near Texas, and we also provide a roadmap for the ongoing research.

Spreading of intolerance under economic stress: Results from a reputation-based model

Science.gov (United States)

Martinez-Vaquero, Luis A.; Cuesta, José A.

2014-08-01

When a population is engaged in successive prisoner's dilemmas, indirect reciprocity through reputation fosters cooperation through the emergence of moral and action rules. A simplified model has recently been proposed where individuals choose between helping others or not and are judged good or bad for it by the rest of the population. The reputation so acquired will condition future actions. In this model, eight strategies (referred to as "leading eight") enforce a high level of cooperation, generate high payoffs, and are therefore resistant to invasions by other strategies. Here we show that, by assigning each individual one of two labels that peers can distinguish (e.g., political ideas, religion, and skin color) and allowing moral and action rules to depend on the label, intolerant behaviors can emerge within minorities under sufficient economic stress. We analyze the sets of conditions where this can happen and also discuss the circumstances under which tolerance can be restored. Our results agree with empirical observations that correlate intolerance and economic stress and predict a correlation between the degree of tolerance of a population and its composition and ethical stance.

Compassion satisfaction, compassion fatigue, anxiety, depression and stress in registered nurses in Australia: study 1 results.

Science.gov (United States)

Hegney, Desley G; Craigie, Mark; Hemsworth, David; Osseiran-Moisson, Rebecca; Aoun, Samar; Francis, Karen; Drury, Vicki

2014-05-01

To explore compassion fatigue and compassion satisfaction with the potential contributing factors of anxiety, depression and stress. To date, no studies have connected the quality of work-life with other contributing and co-existing factors such as depression, anxiety and stress. A self-report exploratory cross sectional survey of 132 nurses working in a tertiary hospital. The reflective assessment risk profile model provides an excellent framework for examining the relationships between the professional quality of work factors and contributing factors within the established risk profiles. The results show a definite pattern of risk progression for the six factors examined for each risk profile. Additionally, burnout and secondary traumatic stress were significantly related to higher anxiety and depression levels. Higher anxiety levels were correlated with nurses who were younger, worked full-time and without a postgraduate qualification. Twenty percent had elevated levels of compassion fatigue: 7.6% having a very distressed profile. At-risk nurses' stress and depression scores were significantly higher than nurses with higher compassion satisfaction scores. The employed nurse workforce would benefit from a psychosocial capacity building intervention that reduces a nurse's risk profile, thus enhancing retention. © 2013 John Wiley & Sons Ltd.

Response Inhibition and Cognitive Appraisal in Clients with Acute Stress Disorder and Posttraumatic Stress Disorder

Directory of Open Access Journals (Sweden)

Abass Abolghasemi

2013-09-01

Full Text Available Objective: The purpose of the present study was to compare response inhibition and cognitive appraisal in clients with acute stress disorder, clients with posttraumatic stress disorder, and normal individuals .Method:This was a comparative study. The sample consisted of 40 clients with acute stress disorder, 40 patients with posttraumatic stress disorder, and 40 normal individuals from Mazandaran province selected through convenience sampling method. Data were collected using Composite International Diagnostic Interview, Stroop Color-Word Test, Posttraumatic Cognitions Inventory, and the Impact of Event Scale. Results:Results showed that individuals with acute stress disorder are less able to inhibit inappropriate responses and have more impaired cognitive appraisals compared to those with posttraumatic stress disorder. Moreover, results showed that response inhibition and cognitive appraisal explain 75% of the variance in posttraumatic stress disorder symptoms and 38% of the variance in posttraumatic stress disorder symptoms .Conclusion:The findings suggest that response inhibition and cognitive appraisal are two variables that influence the severity of posttraumatic stress disorder and acute stress disorder symptoms. Also, these results have important implications for pathology, prevention, and treatment of posttraumatic stress disorder and acute stress disorder

Response inhibition and cognitive appraisal in clients with acute stress disorder and posttraumatic stress disorder.

Science.gov (United States)

Abolghasemi, Abass; Bakhshian, Fereshteh; Narimani, Mohammad

2013-08-01

The purpose of the present study was to compare response inhibition and cognitive appraisal in clients with acute stress disorder, clients with posttraumatic stress disorder, and normal individuals. This was a comparative study. The sample consisted of 40 clients with acute stress disorder, 40 patients with posttraumatic stress disorder, and 40 normal individuals from Mazandaran province selected through convenience sampling method. Data were collected using Composite International Diagnostic Interview, Stroop Color-Word Test, Posttraumatic Cognitions Inventory, and the Impact of Event Scale. Results showed that individuals with acute stress disorder are less able to inhibit inappropriate responses and have more impaired cognitive appraisals compared to those with posttraumatic stress disorder. Moreover, results showed that response inhibition and cognitive appraisal explain 75% of the variance in posttraumatic stress disorder symptoms and 38% of the variance in posttraumatic stress disorder symptoms. The findings suggest that response inhibition and cognitive appraisal are two variables that influence the severity of posttraumatic stress disorder and acute stress disorder symptoms. Also, these results have important implications for pathology, prevention, and treatment of posttraumatic stress disorder and acute stress disorder.

Corticosterone stress response shows long-term repeatability and links to personality in free-living Nazca boobies.

Science.gov (United States)

Grace, Jacquelyn K; Anderson, David J

2014-11-01

The concept of "coping styles", or consistently different responses to stressors, is of broad interest in behavioral ecology and biomedicine. Two critical predictions of this concept are individual consistency of neurophysiological and behavioral responses (relative to population variability) and a negative relationship between aggression/proactivity and hypothalamic-pituitary-adrenal axis reactivity. Recent studies failed to provide strong support for these predictions, especially outside of strictly controlled conditions, and long-term measures to test the first prediction are rare. Here, we demonstrate individual repeatability across 2-3years of maximum circulating corticosterone concentration [CORT] and area under the [CORT] response curve (AUCI) during a standard capture-restraint test in wild, free-living adult Nazca boobies (Sula granti). We also show that the stress response predicts the personality traits aggression and anxiety in these birds (measured in the wild); however, the strength of these results was weak. Maximum [CORT] and AUCI showed higher repeatability between years than baseline [CORT]. After controlling breeding status, sex, mass, date sampled, and their interactions, baseline [CORT] was most closely related to personality traits, followed by AUCI, and then maximum [CORT]. The direction of these relationships depended on whether the testing context was social or non-social. [CORT] parameters had little to no relationship with cross-context plasticity in personality traits. Our results generally affirm two critical predictions of coping styles, but match the emerging trend that these relationships are weak in the wild, and may depend on testing context. Copyright © 2014 Elsevier Inc. All rights reserved.

Role Stress and Work Engagement as Antecedents of Job Satisfaction: Results From Portugal

Directory of Open Access Journals (Sweden)

Daniel Moura

2014-05-01

Full Text Available With more organizations looking for employees who take initiative and respond creatively to the challenges of the job, engagement becomes important at both individual and organizational levels. Engaged employees are generally more satisfied with their work, committed and effective at work. According to the JDR model (Schaufeli & Bakker, 2004, engagement may be produced by two types of working conditions: job demands (i.e., role stress and job resources (i.e., self-efficacy. This study examines the role of role stress (role ambiguity and role conflict and work engagement as antecedents of job satisfaction. A cross sectional study using online questionnaires was conducted. The sample consisted of 312 Portuguese workers. Hierarchical multiple regressions analyses have revealed that job satisfaction was significantly predicted by role conflict and work engagement. Results support JDR model by showing that positive outcomes, such as job satisfaction, may be predicted by motivational process and job demands. On a practical level, JDR model provides a framework for understanding motivating workplaces and engaged and satisfied employees.

On Calculation Methods and Results for Straight Cylindrical Roller Bearing Deflection, Stiffness, and Stress

Science.gov (United States)

Krantz, Timothy L.

2011-01-01

The purpose of this study was to assess some calculation methods for quantifying the relationships of bearing geometry, material properties, load, deflection, stiffness, and stress. The scope of the work was limited to two-dimensional modeling of straight cylindrical roller bearings. Preparations for studies of dynamic response of bearings with damaged surfaces motivated this work. Studies were selected to exercise and build confidence in the numerical tools. Three calculation methods were used in this work. Two of the methods were numerical solutions of the Hertz contact approach. The third method used was a combined finite element surface integral method. Example calculations were done for a single roller loaded between an inner and outer raceway for code verification. Next, a bearing with 13 rollers and all-steel construction was used as an example to do additional code verification, including an assessment of the leading order of accuracy of the finite element and surface integral method. Results from that study show that the method is at least first-order accurate. Those results also show that the contact grid refinement has a more significant influence on precision as compared to the finite element grid refinement. To explore the influence of material properties, the 13-roller bearing was modeled as made from Nitinol 60, a material with very different properties from steel and showing some potential for bearing applications. The codes were exercised to compare contact areas and stress levels for steel and Nitinol 60 bearings operating at equivalent power density. As a step toward modeling the dynamic response of bearings having surface damage, static analyses were completed to simulate a bearing with a spall or similar damage.

Laser-induced stresses versus mechanical stress power measurements during laser ablation of solids

International Nuclear Information System (INIS)

Shannon, M.A.; Russo, R.E.

1995-01-01

Laser-induced stresses resulting from high-power laser-material interactions have been studied extensively. However, the rate of change in mechanical energy, or stress power, due to laser-induced stresses has only recently been investigated. An unanswered question for monitoring laser-material interactions in the far-field is whether stress power differs from stresses measured, particularly with respect to laser-energy coupling to a solid target. This letter shows experimental acoustic data which demonstrate that stress power measured in the far field of the target shows changes in laser-energy coupling, whereas the stresses measured do not. For the ambient medium above the target, stress power and stress together reflect changes in laser-energy coupling. copyright 1995 American Institute of Physics

Reynolds stress scaling in pipe flow turbulence-first results from CICLoPE.

Science.gov (United States)

Örlü, R; Fiorini, T; Segalini, A; Bellani, G; Talamelli, A; Alfredsson, P H

2017-03-13

This paper reports the first turbulence measurements performed in the Long Pipe Facility at the Center for International Cooperation in Long Pipe Experiments (CICLoPE). In particular, the Reynolds stress components obtained from a number of straight and boundary-layer-type single-wire and X-wire probes up to a friction Reynolds number of 3.8×10 4 are reported. In agreement with turbulent boundary-layer experiments as well as with results from the Superpipe, the present measurements show a clear logarithmic region in the streamwise variance profile, with a Townsend-Perry constant of A 2 ≈1.26. The wall-normal variance profile exhibits a Reynolds-number-independent plateau, while the spanwise component was found to obey a logarithmic scaling over a much wider wall-normal distance than the other two components, with a slope that is nearly half of that of the Townsend-Perry constant, i.e. A 2,w ≈A 2 /2. The present results therefore provide strong support for the scaling of the Reynolds stress tensor based on the attached-eddy hypothesis. Intriguingly, the wall-normal and spanwise components exhibit higher amplitudes than in previous studies, and therefore call for follow-up studies in CICLoPE, as well as other large-scale facilities.This article is part of the themed issue 'Toward the development of high-fidelity models of wall turbulence at large Reynolds number'. © 2017 The Author(s).

On the Determination of Concrete Armour Unit Stress including Specific Results related to Dolosse

DEFF Research Database (Denmark)

Burcharth, H. F.; Howell, G.L.; Liu, Z.

1991-01-01

Failures of rubble mound breakwaters armoured with complex types of unreinforced concrete armour units are often due to breakage. This happens when the stresses exceed the material strength. Sufficient parametric studies of the stresses are not yet available to produce design diagrams for structu......Failures of rubble mound breakwaters armoured with complex types of unreinforced concrete armour units are often due to breakage. This happens when the stresses exceed the material strength. Sufficient parametric studies of the stresses are not yet available to produce design diagrams...... and scale effects. Moreover, some results from the Crescent City Prototype Dolosse study are presented and related to results from small-de model tests. A preliminary design diagram for Dolosse ir presented as well....

Mononuclear nonheme iron(III) complexes that show superoxide dismutase-like activity and antioxidant effects against menadione-mediated oxidative stress.

Science.gov (United States)

Hitomi, Yutaka; Iwamoto, Yuji; Kashida, Akihiro; Kodera, Masahito

2015-05-21

This communication describes the superoxide dismutase (SOD)-like activity of mononuclear iron(III) complexes with pentadentate monocarboxylamido ligands. The SOD activity can be controlled by the electronic nature of the substituent group on the ligand. The nitro-substituted complex showed clear cytoprotective activity against menadione-mediated oxidative stress in cultured cells.

Stress tensor and viscosity of water: Molecular dynamics and generalized hydrodynamics results

Science.gov (United States)

Bertolini, Davide; Tani, Alessandro

1995-08-01

The time correlation functions (CF's) of diagonal and off-diagonal components of the stress tensor of water have been calculated at 245 and 298 K in a molecular dynamics (MD) study on 343 molecules in the microcanonical ensemble. We present results obtained at wave number k=0 and at a few finite values of k, in the atomic and molecular formalism. In all cases, more than 98% of these functions are due to the potential term of the stress tensor. At k=0, their main features are a fast oscillatory initial decay, followed by a long-time tail more apparent in the supercooled region. Bulk and shear viscosities, calculated via Green-Kubo integration of the relevant CF at k=0, are underestimated with respect to experimental data, mainly at low temperature, but their ratio (~=2) is correctly reproduced. Both shear and bulk viscosity decrease as a function of k, the latter more rapidly, so that they become almost equal at ~=1 Å-1. Also, both viscosities drop rapidly from their maximum at ω=0. This behavior has been related to the large narrowing observed in the acoustic band, mainly in the supercooled region. The infinite frequency bulk and shear rigidity moduli have been shown to be in fair agreement with the experimental data, provided the MD value used for comparison is that corresponding to the frequency range relevant to ultrasonic measurements. The MD results of stress-stress CF's compare well with those predicted by Bertolini and Tani [Phys. Rev. E 51, 1091 (1995)] at k=0, by an application of generalized hydrodynamics [de Schepper et al., Phys. Rev. A 38, 271 (1988)] in the molecular formalism, to the same model of water (TIP4P) [Jorgensen et al., J. Chem. Phys. 79, 926 (1983)]. These CF's are essentially equal in the atomic and molecular formalism, the only minor difference being restricted to the high frequency librational region of the shear function. By a comparison of atomic and molecular results, we show here that neglecting libration has no effect on the

On to what extent stresses resulting from the earth's surface trigger earthquakes

Science.gov (United States)

Klose, C. D.

2009-12-01

The debate on static versus dynamic earthquake triggering mainly concentrates on endogenous crustal forces, including fault-fault interactions or seismic wave transients of remote earthquakes. Incomprehensibly, earthquake triggering due to surface processes, however, still receives little scientific attention. This presentation continues a discussion on the hypothesis of how “tiny” stresses stemming from the earth's surface can trigger major earthquakes, such as for example, China's M7.9 Wenchuan earthquake of May 2008. This seismic event is thought to be triggered by up to 1.1 billion metric tons of water (~130m) that accumulated in the Minjiang River Valley at the eastern margin of the Longmen Shan. Specifically, the water level rose by ~80m (static), with additional seasonal water level changes of ~50m (dynamic). Two and a half years prior to mainshock, static and dynamic Coulomb failure stresses were induced on the nearby Beichuan thrust fault system at <17km depth. Triggering stresses were equivalent to levels of daily tides and perturbed a fault area measuring 416+/-96km^2. The mainshock ruptured after 2.5 years when only the static stressing regime was predominant and the transient stressing (seasonal water level) was infinitesimal small. The short triggering delay of about 2 years suggests that the Beichuan fault might have been near the end of its seismic cycle, which may also confirm what previous geological findings have indicated. This presentation shows on to what extend the static and 1-year periodic triggering stress perturbations a) accounted for equivalent tectonic loading, given a 4-10kyr earthquake cycle and b) altered the background seismicity beneath the valley, i.e., daily event rate and earthquake size distribution.

The impact of training process on the stress tests results of women cross country skiing representation.

OpenAIRE

Fusková, Dana

2015-01-01

Title: The impact of training process on the stress tests results of women cross country skiing representation. Aim: The aim of this thesis is the comparison of the results of stress tests carried out preparatory period before and after the preparation period and whether the results were influenced by the applied training process. Methods: In this thesis was used background research of professional publications, content analyzes of documents and comparison of the results of stress tests and c...

Stress, lifestyle, and quality of life in midlife and older Australian women: results from the Stress and the Health of Women Study.

Science.gov (United States)

Seib, Charrlotte; Whiteside, Eliza; Lee, Kathryn; Humphreys, Janice; Tran, Tiet Hanh Dao; Chopin, Lisa; Anderson, Debra

2014-01-01

Chronic psychological stress may pose a serious threat to health, although the mechanisms are not fully understood. This study examines the impact of stress on modifiable lifestyle factors, depressive symptoms, health-related quality of life (HRQOL) and chronic illness in older Australian women. Cross-sectional data were collected from a random sample of 181 older adults aged 60 to 70 years from rural and urban areas of South-East Queensland, Australia. We used structural equation modelling to examine associations between stress, modifiable lifestyle factors, HRQOL, and chronic illness. Parameter estimates show that older women who reported life stressors where they felt helpless and feared for their life (high-magnitude stressors) also reported higher body mass index (p = .03) and more chronic illness (p unhealthy lifestyle factors. Findings highlight the need for more research on how stress reduction, a healthy lifestyle, and positive coping strategies can be used to reduce the effects of high-magnitude stress on HRQOL and chronic illness. Copyright © 2014 Jacobs Institute of Women's Health. Published by Elsevier Inc. All rights reserved.

Thermotolerant Yeast Strains Adapted by Laboratory Evolution Show Trade-Off at Ancestral Temperatures and Preadaptation to Other Stresses.

Science.gov (United States)

Caspeta, Luis; Nielsen, Jens

2015-07-21

A major challenge for the production of ethanol from biomass-derived feedstocks is to develop yeasts that can sustain growth under the variety of inhibitory conditions present in the production process, e.g., high osmolality, high ethanol titers, and/or elevated temperatures (≥ 40 °C). Using adaptive laboratory evolution, we previously isolated seven Saccharomyces cerevisiae strains with improved growth at 40 °C. Here, we show that genetic adaptations to high temperature caused a growth trade-off at ancestral temperatures, reduced cellular functions, and improved tolerance of other stresses. Thermotolerant yeast strains showed horizontal displacement of their thermal reaction norms to higher temperatures. Hence, their optimal and maximum growth temperatures increased by about 3 °C, whereas they showed a growth trade-off at temperatures below 34 °C. Computational analysis of the physical properties of proteins showed that the lethal temperature for yeast is around 49 °C, as a large fraction of the yeast proteins denature above this temperature. Our analysis also indicated that the number of functions involved in controlling the growth rate decreased in the thermotolerant strains compared with the number in the ancestral strain. The latter is an advantageous attribute for acquiring thermotolerance and correlates with the reduction of yeast functions associated with loss of respiration capacity. This trait caused glycerol overproduction that was associated with the growth trade-off at ancestral temperatures. In combination with altered sterol composition of cellular membranes, glycerol overproduction was also associated with yeast osmotolerance and improved tolerance of high concentrations of glucose and ethanol. Our study shows that thermal adaptation of yeast is suitable for improving yeast resistance to inhibitory conditions found in industrial ethanol production processes. Yeast thermotolerance can significantly reduce the production costs of biomass

Results of fatigue tests and prediction of fatigue life under superposed stress wave and combined superposed stress wave

International Nuclear Information System (INIS)

Takasugi, Shunji; Horikawa, Takeshi; Tsunenari, Toshiyasu; Nakamura, Hiroshi

1983-01-01

In order to examine fatigue life prediction methods at high temperatures where creep damage need not be taken into account, fatigue tests were carried out on plane bending specimens of alloy steels (SCM 435, 2 1/4Cr-1Mo) under superposed and combined superposed stress waves at room temperature and 500 0 C. The experimental data were compared with the fatigue lives predicted by using the cycle counting methods (range pair, range pair mean and zero-cross range pair mean methods), the modified Goodman's equation and the modified Miner's rule. The main results were as follows. (1) The fatigue life prediction method which is being used for the data at room temperature is also applicable to predict the life at high temperatures. The range pair mean method is especially better than other cycle counting methods. The zero-cross range pair mean method gives the estimated lives on the safe side of the experimental lives. (2) The scatter bands of N-bar/N-barsub(es) (experimental life/estimated life) becomes narrower when the following equation is used instead of the modified Goodman's equation for predicting the effect of mean stress on fatigue life. σ sub(t) = σ sub(a) / (1 - Sigma-s sub(m) / kσ sub(B)) σ sub(t); stress amplitude at zero mean stress (kg/mm 2 ) σ sub(B); tensile strength (kg/mm 2 ) σ sub(m); mean stress (kg/mm 2 ) σ sub(a); stress amplitude (kg/mm 2 ) k; modified coefficient of σ sub(B) (author)

Hippocampal structural plasticity accompanies the resulting contextual fear memory following stress and fear conditioning.

Science.gov (United States)

Giachero, Marcelo; Calfa, Gaston D; Molina, Victor A

2013-10-15

The present research investigated the resulting contextual fear memory and structural plasticity changes in the dorsal hippocampus (DH) following stress and fear conditioning. This combination enhanced fear retention and increased the number of total and mature dendritic spines in DH. Intra-basolateral amygdala (BLA) infusion of midazolam prior to stress prevented both the enhancement of fear retention and an increase in the density of total and mature dendritic spines in DH. These findings emphasize the role of the stress-induced attenuation of GABAergic neurotransmission in BLA in the promoting influence of stress on fear memory and on synaptic remodeling in DH. In conclusion, the structural remodeling in DH accompanied the facilitated fear memory following a combination of fear conditioning and stressful stimulation.

The origin of the distinction between microscopic formulas for stress and Cauchy stress

OpenAIRE

Chen, Youping

2016-01-01

Stress is calculated routinely in atomistic simulations. The widely used microscopic stress formulas derived from classical or quantum mechanics, however, are distinct from the concept of Cauchy stress, i.e., the true mechanical tress. This work examines various atomistic stress formulations and their inconsistencies. Using standard mathematic theorems and the law of mechanics, we show that Cauchy stress results unambiguously from the definition of internal force density, thereby removing the...

Results of stress tests of European nuclear power plants after the Fukushima-Daiichi accident

International Nuclear Information System (INIS)

Kovacs, Zoltan; Novakova, Helena

2012-01-01

In response to the Fukushima-Daiichi accident, the European Council laid down the requirement that a transparent and comprehensive risk assessment exercise ('stress tests') be carried out at each European nuclear power plant. The stress tests concentrated on the nuclear power plants' safety margins in the light of the lessons learned from the accident. The reviews focused on natural external events including earthquake, tsunami and extreme weather, loss of safety functions, and severe accident management. The stress test procedure comprised 3 steps: (i) The nuclear facility operators performed the stress tests and prepared proposals for safety improvements. (ii) The national regulators performed independent reviews of the stress tests and prepared national reports. (iii) The reports submitted by the national regulators were subjected to review at a European level. The article describes the scope of the stress tests and their results, verified at the European level. (orig.)

Gun Shows and Gun Violence: Fatally Flawed Study Yields Misleading Results

Science.gov (United States)

Hemenway, David; Webster, Daniel; Pierce, Glenn; Braga, Anthony A.

2010-01-01

A widely publicized but unpublished study of the relationship between gun shows and gun violence is being cited in debates about the regulation of gun shows and gun commerce. We believe the study is fatally flawed. A working paper entitled “The Effect of Gun Shows on Gun-Related Deaths: Evidence from California and Texas” outlined this study, which found no association between gun shows and gun-related deaths. We believe the study reflects a limited understanding of gun shows and gun markets and is not statistically powered to detect even an implausibly large effect of gun shows on gun violence. In addition, the research contains serious ascertainment and classification errors, produces results that are sensitive to minor specification changes in key variables and in some cases have no face validity, and is contradicted by 1 of its own authors’ prior research. The study should not be used as evidence in formulating gun policy. PMID:20724672

Tianeptine, olanzapine and fluoxetine show similar restoring effects on stress induced molecular changes in mice brain: An FT-IR study

Science.gov (United States)

Türker-Kaya, Sevgi; Mutlu, Oğuz; Çelikyurt, İpek K.; Akar, Furuzan; Ulak, Güner

2016-05-01

Chronic stress which can cause a variety of disorders and illness ranging from metabolic and cardiovascular to mental leads to alterations in content, structure and dynamics of biomolecules in brain. The determination of stress-induced changes along with the effects of antidepressant treatment on these parameters might bring about more effective therapeutic strategies. In the present study, we investigated unpredictable chronic mild stress (UCMS)-induced changes in biomolecules in mouse brain and the restoring effects of tianeptine (TIA), olanzapine (OLZ) and fluoxetine (FLX) on these variations, by Fourier transform infrared (FT-IR) spectroscopy. The results revealed that chronic stress causes different membrane packing and an increase in lipid peroxidation, membrane fluidity. A significant increment for lipid/protein, Cdbnd O/lipid, CH3/lipid, CH2/lipid, PO-2/lipid, COO-/lipid and RNA/protein ratios but a significant decrease for lipid/protein ratios were also obtained. Additionally, altered protein secondary structure components were estimated, such as increment in random coils and beta structures. The administration of TIA, OLZ and FLX drugs restored these stress-induced variations except for alterations in protein structure and RNA/protein ratio. This may suggest that these drugs have similar restoring effects on the consequences of stress activity in brain, in spite of the differences in their action mechanisms. All findings might have importance in understanding molecular mechanisms underlying chronic stress and contribute to studies aimed for drug development.

On the Determination of Concrete Armour Unit Stress including Specific Results related to Dolosse

OpenAIRE

Burcharth, H. F.; Howell, G.L.; Liu, Z.

1991-01-01

Failures of rubble mound breakwaters armoured with complex types of unreinforced concrete armour units are often due to breakage. This happens when the stresses exceed the material strength. Sufficient parametric studies of the stresses are not yet available to produce design diagrams for structural integrity. The paper presents a general discussion of the problems related to stress etermination and describes the results and the analyses of model tests with 200 kg and 200 g load-cell instrume...

Acculturation and psychosocial stress show differential relationships to insulin resistance (HOMA) and body fat distribution in two groups of blacks living in the US Virgin Islands.

Science.gov (United States)

Tull, Eugene S.; Thurland, Anne; LaPorte, Ronald E.; Chambers, Earle C.

2003-01-01

The objective of this study was to determine whether acculturation and psychosocial stress exert differential effects on body fat distribution and insulin resistance among native-born African Americans and African-Caribbean immigrants living in the US Virgin Islands (USVI). Data collected from a non-diabetic sample of 183 USVI-born African Americans and 296 African-Caribbean immigrants age > 20 on the island of St. Croix, USVI were studied. Information on demographic characteristics, acculturation and psychosocial stress was collected by questionnaire. Anthropometric measurements were taken, and serum glucose and insulin were measured from fasting blood samples. Insulin resistance was estimated by the homeostasis model assessment (HOMA) method. The results showed that in multivariate regression analyses, controlling for age, education, gender, BMI, waist circumference, family history of diabetes, smoking and alcohol consumption, acculturation was independently related to logarithm of HOMA (InHOMA) scores among USVI-born African Americans, but not among African-Caribbean immigrants. In contrast, among USVI-born African Americans psychosocial stress was not significantly related to InHOMA, while among African-Caribbean immigrants psychosocial stress was independently related to InHOMA in models that included BMI, but not in those which included waist circumference. This study suggests that acculturation and psychosocial stress may have a differential effect on body fat distribution and insulin resistance among native-born and immigrant blacks living in the US Virgin Islands. PMID:12911254

Extract of Bauhinia vahlii Shows Antihyperglycemic Activity, Reverses Oxidative Stress, and Protects against Liver Damage in Streptozotocin-induced Diabetic Rats

Science.gov (United States)

Elbanna, Ahmed H.; Nooh, Mohammed M.; Mahrous, Engy A.; Khaleel, Amal E.; Elalfy, Taha S.

2017-01-01

Background: Several studies have affirmed the effectiveness of some Bauhinia plants as antihyperglycemic agents. Objective: We investigated the possible effect of Bauhinia vahlii leaves extract in reducing hyperglycemia and reversing signs of organ damage associated with diabetes in streptozotocin (STZ) rat model. Materials and Methods: Both polar fraction of the B. vahlii leaves (defatted ethanolic extract [DEE]) and nonpolar fraction (n-hexane extract) were evaluated in vitro for α-glucosidase inhibition and 2,2-diphenyl-1-picrylhydrazyl radical scavenging potential. DEE was selected for further in vivo studies and was administered at two doses, i.e., 150 or 300 mg/kg to STZ-diabetic rats for 4 weeks. Results: Only DEE exhibited in vitro antioxidant and antihyperglycemic activities and its oral administration at both dose levels resulted in significant reduction in fasting blood glucose and glycated hemoglobin. Furthermore, signs of oxidative stress as indicated by hepatic reduced glutathione, nitric oxide, and malondialdehyde levels were completely reversed. In addition, histopathological examination and measurement of serum aspartate transaminase and alanine transaminase levels showed that DEE protected the liver from signs of liver pathogenesis when compared to diabetic untreated animals and those treated with metformin. Phytochemical analysis of DEE showed high flavonoids content with quercitrin as the major constituent along with other quercetin glycosides. Conclusion: This study strongly highlights the possible beneficial effect of B. vahlii leaves extract in relieving hyperglycemia and liver damage in STZ-diabetic rats and recommends further investigation of the value of quercetin derivatives in controlling diabetes and ameliorating liver damage associated with it. SUMMARY The polar fraction of the Bauhinia vahlii leaves (defatted ethanolic extract [DEE]) exhibited both in vitro antioxidant activity in 2,2-diphenyl-1-picrylhydrazyl scavenging assay and

Transcriptome profiling of low temperature-treated cassava apical shoots showed dynamic responses of tropical plant to cold stress

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An Dong

2012-02-01

Full Text Available Abstract Background Cassava is an important tropical root crop adapted to a wide range of environmental stimuli such as drought and acid soils. Nevertheless, it is an extremely cold-sensitive tropical species. Thus far, there is limited information about gene regulation and signalling pathways related to the cold stress response in cassava. The development of microarray technology has accelerated the study of global transcription profiling under certain conditions. Results A 60-mer oligonucleotide microarray representing 20,840 genes was used to perform transcriptome profiling in apical shoots of cassava subjected to cold at 7°C for 0, 4 and 9 h. A total of 508 transcripts were identified as early cold-responsive genes in which 319 sequences had functional descriptions when aligned with Arabidopsis proteins. Gene ontology annotation analysis identified many cold-relevant categories, including 'Response to abiotic and biotic stimulus', 'Response to stress', 'Transcription factor activity', and 'Chloroplast'. Various stress-associated genes with a wide range of biological functions were found, such as signal transduction components (e.g., MAP kinase 4, transcription factors (TFs, e.g., RAP2.11, and reactive oxygen species (ROS scavenging enzymes (e.g., catalase 2, as well as photosynthesis-related genes (e.g., PsaL. Seventeen major TF families including many well-studied members (e.g., AP2-EREBP were also involved in the early response to cold stress. Meanwhile, KEGG pathway analysis uncovered many important pathways, such as 'Plant hormone signal transduction' and 'Starch and sucrose metabolism'. Furthermore, the expression changes of 32 genes under cold and other abiotic stress conditions were validated by real-time RT-PCR. Importantly, most of the tested stress-responsive genes were primarily expressed in mature leaves, stem cambia, and fibrous roots rather than apical buds and young leaves. As a response to cold stress in cassava, an increase

Blue lighting accelerates post-stress relaxation: Results of a preliminary study.

Science.gov (United States)

Minguillon, Jesus; Lopez-Gordo, Miguel Angel; Renedo-Criado, Diego A; Sanchez-Carrion, Maria Jose; Pelayo, Francisco

2017-01-01

Several authors have studied the influence of light on both human physiology and emotions. Blue light has been proved to reduce sleepiness by suppression of melatonin secretion and it is also present in many emotion-related studies. Most of these have a common lack of objective methodology since results and conclusions are based on subjective perception of emotions. The aim of this work was the objective assessment of the effect of blue lighting in post-stress relaxation, in comparison with white lighting, by means of bio-signals and standardized procedures. We conducted a study in which twelve healthy volunteers were stressed and then performed a relaxation session within a chromotherapy room with blue (test group) or white (control group) lighting. We conclude that the blue lighting accelerates the relaxation process after stress in comparison with conventional white lighting. The relaxation time decreased by approximately three-fold (1.1 vs. 3.5 minutes). We also observed a convergence time (3.5-5 minutes) after which the advantage of blue lighting disappeared. This supports the relationship between color of light and stress, and the observations reported in previous works. These findings could be useful in clinical and educational environments, as well as in daily-life context and emerging technologies such as neuromarketing. However, our study must be extended to draw reliable conclusions and solid scientific evidence.

Blue lighting accelerates post-stress relaxation: Results of a preliminary study.

Directory of Open Access Journals (Sweden)

Jesus Minguillon

Full Text Available Several authors have studied the influence of light on both human physiology and emotions. Blue light has been proved to reduce sleepiness by suppression of melatonin secretion and it is also present in many emotion-related studies. Most of these have a common lack of objective methodology since results and conclusions are based on subjective perception of emotions. The aim of this work was the objective assessment of the effect of blue lighting in post-stress relaxation, in comparison with white lighting, by means of bio-signals and standardized procedures. We conducted a study in which twelve healthy volunteers were stressed and then performed a relaxation session within a chromotherapy room with blue (test group or white (control group lighting. We conclude that the blue lighting accelerates the relaxation process after stress in comparison with conventional white lighting. The relaxation time decreased by approximately three-fold (1.1 vs. 3.5 minutes. We also observed a convergence time (3.5-5 minutes after which the advantage of blue lighting disappeared. This supports the relationship between color of light and stress, and the observations reported in previous works. These findings could be useful in clinical and educational environments, as well as in daily-life context and emerging technologies such as neuromarketing. However, our study must be extended to draw reliable conclusions and solid scientific evidence.

Stress analysis of feeder bends using neutrons: new results and cumulative impacts

Energy Technology Data Exchange (ETDEWEB)

Banks, D.; Donaberger, R. [Canadian Neutron Beam Centre, Chalk River, ON (Canada); Leitch, B. [Atomic Energy of Canada Limited, Chalk River, ON (Canada); Rogge, R.B. [Canadian Neutron Beam Centre, Chalk River, ON (Canada)

2014-07-01

Neutron diffraction has played a vital role in stress analysis of bends in carbon steel pipes, known as feeder pipes, in CANDU reactors. Due to incidents of cracking of feeders, extensive R&D programs to manage feeder cracking have been implemented over about ten years. We review the cumulative impacts of this research from the view point of the stress analysis using neutrons, and present new results by examining a feeder bend with a partial crack both experimentally using neutron diffraction and theoretically using a finite element model. (author)

Oxidative Stress Resulting From Helicobacter pylori Infection Contributes to Gastric CarcinogenesisSummary

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Lindsay D. Butcher

2017-05-01

Full Text Available Helicobacter pylori is a gram-negative, microaerophilic bacterium that infects the stomach and can lead to, among other disorders, the development of gastric cancer. The inability of the host to clear the infection results in a chronic inflammatory state with continued oxidative stress within the tissue. Reactive oxygen species and reactive nitrogen species produced by the immune and epithelial cells damage the host cells and can result in DNA damage. H pylori has evolved to evoke this damaging response while blunting the host’s efforts to kill the bacteria. This long-lasting state with inflammation and oxidative stress can result in gastric carcinogenesis. Continued efforts to better understand the bacterium and the host response will serve to prevent or provide improved early diagnosis and treatment of gastric cancer. Keywords: AP Endonuclease, DNA Damage, H pylori, Gastric Cancer, Oxidative Stress

The Yeast Environmental Stress Response Regulates Mutagenesis Induced by Proteotoxic Stress

Science.gov (United States)

Shor, Erika; Fox, Catherine A.; Broach, James R.

2013-01-01

Conditions of chronic stress are associated with genetic instability in many organisms, but the roles of stress responses in mutagenesis have so far been elucidated only in bacteria. Here, we present data demonstrating that the environmental stress response (ESR) in yeast functions in mutagenesis induced by proteotoxic stress. We show that the drug canavanine causes proteotoxic stress, activates the ESR, and induces mutagenesis at several loci in an ESR-dependent manner. Canavanine-induced mutagenesis also involves translesion DNA polymerases Rev1 and Polζ and non-homologous end joining factor Ku. Furthermore, under conditions of chronic sub-lethal canavanine stress, deletions of Rev1, Polζ, and Ku-encoding genes exhibit genetic interactions with ESR mutants indicative of ESR regulating these mutagenic DNA repair processes. Analyses of mutagenesis induced by several different stresses showed that the ESR specifically modulates mutagenesis induced by proteotoxic stress. Together, these results document the first known example of an involvement of a eukaryotic stress response pathway in mutagenesis and have important implications for mechanisms of evolution, carcinogenesis, and emergence of drug-resistant pathogens and chemotherapy-resistant tumors. PMID:23935537

Overall bolt stress optimization

DEFF Research Database (Denmark)

Pedersen, Niels Leergaard

2013-01-01

The state of stress in bolts and nuts with International Organization for Standardization metric thread design is examined and optimized. The assumed failure mode is fatigue, so the applied preload and the load amplitude together with the stress concentrations define the connection strength....... Maximum stress in the bolt is found at the fillet under the head, at the thread start, or at the thread root. To minimize the stress concentration, shape optimization is applied. Nut shape optimization also has a positive effect on the maximum stress. The optimization results show that designing a nut......, which results in a more evenly distribution of load along the engaged thread, has a limited influence on the maximum stress due to the stress concentration at the first thread root. To further reduce the maximum stress, the transition from bolt shank to the thread must be optimized. Stress reduction...

Statistical evaluation of characteristic SDDLV-induced stress resultants to discriminate between undamaged and damaged elements

DEFF Research Database (Denmark)

Hansen, Lasse Majgaard; Johansen, Rasmus Johan; Ulriksen, Martin Dalgaard

2015-01-01

of modified characteristic stress resultants, which are compared to a pre-defined tolerance value, without any thorough statistical evaluation. In the present paper, it is tested whether three widely-used statistical pattern-recognition-based damage-detection methods can provide an effective statistical...... evaluation of the characteristic stress resultants, hence facilitating general discrimination between damaged and undamaged elements. The three detection methods in question enable outlier analysis on the basis of, respectively, Euclidian distance, Hotelling’s statistics, and Mahalanobis distance. The study...... alternately to an undamaged reference model with known stiffness matrix, hereby, theoretically, yielding characteristic stress resultants approaching zero in the damaged elements. At present, the discrimination between potentially damaged elements and undamaged ones is typically conducted on the basis...

Symposium on teacher stress. Occupational stress among vocational teachers.

Science.gov (United States)

Pithers, R T; Fogarty, G J

1995-03-01

There is a widespread belief that work related stress among teachers is serious, with implications for teachers' health status and performance. The difficulty with interpreting data on teacher stress is that the measuring instruments used are often neither standardised nor sometimes focused on stressors pertinent to the occupational roles of teachers. This study, therefore, uses a recently developed test instrument called the Occupational Stress Inventory (OSI) which concisely measures occupational stress, strain and coping resources. Data were obtained, using the OSI, from a group of vocational teachers and compared to a group of professional non-teachers. Overall the results showed a significantly higher level of teacher stress, although only one of 10 stress and strain measures contributed to this effect. The implications for teachers, in terms of occupational role, are discussed.

Adenosine-stress dynamic real-time myocardial perfusion CT and adenosine-stress first-pass dual-energy myocardial perfusion CT for the assessment of acute chest pain: Initial results

Energy Technology Data Exchange (ETDEWEB)

Weininger, Markus [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Schoepf, U. Joseph, E-mail: schoepf@musc.edu [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Department of Medicine, Division of Cardiology, Medical University of South Carolina, Charleston, SC (United States); Ramachandra, Ashok [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Fink, Christian [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany); Rowe, Garrett W.; Costello, Philip [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Henzler, Thomas [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany)

2012-12-15

Purpose: Recent innovations in CT enable the evolution from mere morphologic imaging to dynamic and functional testing. We describe our initial experience performing myocardial stress perfusion CT in a clinical population with acute chest pain. Methods and materials: Myocardial stress perfusion CT was performed on twenty consecutive patients (15 men, 5 women; mean age 65 ± 8 years) who presented with acute chest pain and were clinically referred for stress/rest SPECT and cardiac MRI. Prior to CT each patient was randomly assigned either to Group A or to Group B in a consecutive order (10 patients per group). Group A underwent adenosine-stress dynamic real-time myocardial perfusion CT using a novel “shuttle” mode on a 2nd generation dual-source CT. Group B underwent adenosine-stress first-pass dual-energy myocardial perfusion CT using the same CT scanner in dual-energy mode. Two experienced observers visually analyzed all CT perfusion studies. CT findings were compared with MRI and SPECT. Results: In Group A 149/170 myocardial segments (88%) could be evaluated. Real-time perfusion CT (versus SPECT) had 86% (84%) sensitivity, 98% (92%) specificity, 94% (88%) positive predictive value, and 96% (92%) negative predictive value in comparison with perfusion MRI for the detection of myocardial perfusion defects. In Group B all myocardial segments were available for analysis. Compared with MRI, dual-energy myocardial perfusion CT (versus SPECT) had 93% (94%) sensitivity, 99% (98%) specificity, 92% (88%) positive predictive value, and 96% (94%) negative predictive value for detecting hypoperfused myocardial segments. Conclusion: Our results suggest the clinical feasibility of myocardial perfusion CT imaging in patients with acute chest pain. Compared to MRI and SPECT both, dynamic real-time perfusion CT and first-pass dual-energy perfusion CT showed good agreement for the detection of myocardial perfusion defects.

Adenosine-stress dynamic real-time myocardial perfusion CT and adenosine-stress first-pass dual-energy myocardial perfusion CT for the assessment of acute chest pain: Initial results

International Nuclear Information System (INIS)

Weininger, Markus; Schoepf, U. Joseph; Ramachandra, Ashok; Fink, Christian; Rowe, Garrett W.; Costello, Philip; Henzler, Thomas

2012-01-01

Purpose: Recent innovations in CT enable the evolution from mere morphologic imaging to dynamic and functional testing. We describe our initial experience performing myocardial stress perfusion CT in a clinical population with acute chest pain. Methods and materials: Myocardial stress perfusion CT was performed on twenty consecutive patients (15 men, 5 women; mean age 65 ± 8 years) who presented with acute chest pain and were clinically referred for stress/rest SPECT and cardiac MRI. Prior to CT each patient was randomly assigned either to Group A or to Group B in a consecutive order (10 patients per group). Group A underwent adenosine-stress dynamic real-time myocardial perfusion CT using a novel “shuttle” mode on a 2nd generation dual-source CT. Group B underwent adenosine-stress first-pass dual-energy myocardial perfusion CT using the same CT scanner in dual-energy mode. Two experienced observers visually analyzed all CT perfusion studies. CT findings were compared with MRI and SPECT. Results: In Group A 149/170 myocardial segments (88%) could be evaluated. Real-time perfusion CT (versus SPECT) had 86% (84%) sensitivity, 98% (92%) specificity, 94% (88%) positive predictive value, and 96% (92%) negative predictive value in comparison with perfusion MRI for the detection of myocardial perfusion defects. In Group B all myocardial segments were available for analysis. Compared with MRI, dual-energy myocardial perfusion CT (versus SPECT) had 93% (94%) sensitivity, 99% (98%) specificity, 92% (88%) positive predictive value, and 96% (94%) negative predictive value for detecting hypoperfused myocardial segments. Conclusion: Our results suggest the clinical feasibility of myocardial perfusion CT imaging in patients with acute chest pain. Compared to MRI and SPECT both, dynamic real-time perfusion CT and first-pass dual-energy perfusion CT showed good agreement for the detection of myocardial perfusion defects.

Tokyo Motor Show 2003; Tokyo Motor Show 2003

Energy Technology Data Exchange (ETDEWEB)

Joly, E.

2004-01-01

The text which follows present the different techniques exposed during the 37. Tokyo Motor Show. The report points out the great tendencies of developments of the Japanese automobile industry. The hybrid electric-powered vehicles or those equipped with fuel cells have been highlighted by the Japanese manufacturers which allow considerable budgets in the research of less polluting vehicles. The exposed models, although being all different according to the manufacturer, use always a hybrid system: fuel cell/battery. The manufacturers have stressed too on the intelligent systems for navigation and safety as well as on the design and comfort. (O.M.)

Stress and Health

DEFF Research Database (Denmark)

Rod, Naja Hulvej

2014-01-01

and behavioral mechanisms. Stress is a complex concept and in order to better understand the relation between stress and health, the dissertation works with a clear distinction between the health consequences of different types of stress including external stressors, perceived stress, and measures of the stress......’s disease patients. Results The combined evidence of this dissertation shows a moderately higher risk of some common chronic disorders including cardiovascular disease and atopic disorders among individuals exposed to work-related stressors and perceived stress. Most empirical studies also report higher...... of pathways. The physiological stress response has the ability to directly affect vital body systems including the cardiovascular, immune, and metabolic systems. Further, stress can lead to unfavorable changes in health-related behavior, impaired sleep and poor mental health. An increasing number of well...

MRI Shows that Exhaustion Syndrome Due to Chronic Occupational Stress is Associated with Partially Reversible Cerebral Changes.

Science.gov (United States)

Savic, I; Perski, A; Osika, W

2018-03-01

The present study investigates the cerebral effects of chronic occupational stress and its possible reversibility. Forty-eight patients with occupational exhaustion syndrome (29 women) and 80 controls (47 women) underwent structural magnetic resonance imaging (MRI) and neuropsychological testing. Forty-four participants (25 patients, 19 controls) also completed a second MRI scan after 1-2 years. Only patients received cognitive therapy. The stressed group at intake had reduced thickness in the right prefrontal cortex (PFC) and left superior temporal gyrus (STG), enlarged amygdala volumes, and reduced caudate volumes. Except for the caudate volume, these abnormalities were more pronounced in females. They were all related to perceived stress, which was similar for both genders. Thickness of the PFC also correlated with an impaired ability to down-modulate negative emotions. Thinning of PFC and reduction of caudate volume normalized in the follow-up. The amygdala enlargement and the left STG thinning remained. Longitudinal changes were not detected among controls. Chronic occupational stress was associated with partially reversible structural abnormalities in key regions for stress processing. These changes were dynamically correlated with the degree of perceived stress, highlighting a possible causal link. They seem more pronounced in women, and could be a substrate for an increased cerebral vulnerability to stress-related psychiatric disorders. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Thermotolerant Yeast Strains Adapted by Laboratory Evolution Show Trade-Off at Ancestral Temperatures and Preadaptation to Other Stresses

DEFF Research Database (Denmark)

Caspeta, Luis; Nielsen, Jens

2015-01-01

adaptive laboratory evolution, we previously isolated seven Saccharomyces cerevisiae strains with improved growth at 40°C. Here, we show that genetic adaptations to high temperature caused a growth trade-off at ancestral temperatures, reduced cellular functions, and improved tolerance of other stresses...... in the ancestral strain. The latter is an advantageous attribute for acquiring thermotolerance and correlates with the reduction of yeast functions associated with loss of respiration capacity. This trait caused glycerol overproduction that was associated with the growth trade-off at ancestral temperatures....... In combination with altered sterol composition of cellular membranes, glycerol overproduction was also associated with yeast osmotolerance and improved tolerance of high concentrations of glucose and ethanol. Our study shows that thermal adaptation of yeast is suitable for improving yeast resistance...

Modeling of stresses at grain boundaries with respect to occurrence of stress corrosion cracking

Energy Technology Data Exchange (ETDEWEB)

Kozaczek, K.J. [Oak Ridge National Lab., TN (United States); Sinharoy, A.; Ruud, C.O. [Pennsylvania State Univ., University Park, PA (United States); McIlree, A.R. [Electric Power Research Institute, Palo Alto, CA (United States)

1995-12-31

The distributions of elastic stresses/strains in the grain boundary regions were studied by the analytical and the finite element models. The grain boundaries represent the sites where stress concentration occurs as a result of discontinuity of elastic properties across the grain boundary and the presence of second phase particles elastically different from the surrounding matrix grains. A quantitative analysis of those stresses for steels and nickel based alloys showed that the stress concentrations in the grain boundary regions are high enough to cause a local microplastic deformation even when the material is in the macroscopic elastic regime. The stress redistribution as a result of such a plastic deformation was discussed.

Stress in Context: Morpho-Syntactic Properties Affect Lexical Stress Assignment in Reading Aloud.

Science.gov (United States)

Spinelli, Giacomo; Sulpizio, Simone; Primativo, Silvia; Burani, Cristina

2016-01-01

Recent findings from English and Russian have shown that grammatical category plays a key role in stress assignment. In these languages, some grammatical categories have a typical stress pattern and this information is used by readers. However, whether readers are sensitive to smaller distributional differences and other morpho-syntactic properties (e.g., gender, number, person) remains unclear. We addressed this issue in word and non-word reading in Italian, a language in which: (1) nouns and verbs differ in the proportion of words with a dominant stress pattern; (2) information specified by words sharing morpho-syntactic properties may contrast with other sources of information, such as stress neighborhood. Both aspects were addressed in two experiments in which context words were used to induce the desired morpho-syntactic properties. Experiment 1 showed that the relatively different proportions of stress patterns between grammatical categories do not affect stress processing in word reading. In contrast, Experiment 2 showed that information specified by words sharing morpho-syntactic properties outweighs stress neighborhood in non-word reading. Thus, while general information specified by grammatical categories may not be used by Italian readers, stress neighbors with morpho-syntactic properties congruent with those of the target stimulus have a primary role in stress assignment. These results underscore the importance of expanding investigations of stress assignment beyond single words, as current models of single-word reading seem unable to account for our results.

Association Between Stress-Related Sleep Reactivity and Metacognitive Beliefs About Sleep in Insomnia Disorder: Preliminary Results.

Science.gov (United States)

Palagini, Laura; Bruno, Rosa Maria; Paolo, Toti; Caccavale, Lisa; Gronchi, Alessia; Mauri, Mauro; Riemann, Dieter; Drake, Christopher L

2016-01-01

To evaluate the relation between stress-related sleep reactivity and metacognitive beliefs about sleep in subjects with insomnia disorder (93) and in a group of healthy controls (30) a set of variables, including Ford Insomnia Response to Stress Test (FIRST) and Metacognition Questionnaire-Insomnia (MCQ-I), have been used. Internal consistency of the Italian version of FIRST was studied. Univariate correlation, regression analysis, and principal component analysis were also performed. The Italian version of FIRST showed good internal consistency and discriminant validity. Sleep reactivity was higher in women (p sleep (p sleep reactivity. Therapeutic strategies acting selectively on metacognition to reduce stress-related sleep reactivity in insomnia may be useful.

Writing about stress: the impact of a stress-management programme on staff accounts of dealing with stress.

Science.gov (United States)

van Oorsouw, Wietske M W J; Embregts, Petri J C M; Bosman, Anna M T; Jahoda, Andrew

2014-05-01

Helping staff serving clients with intellectual disability and challenging behaviour to cope with stress has implications for their own well-being and for the lives of those they support. This study examined staff members' views of stress and the effectiveness of a stress-management intervention. Effectiveness was assessed using written assignments regarding stress management, and changes in views presented were tested in a pre- and post-test control group design. In the first phase, a content analysis was conducted across groups, which revealed that participants expressed a broad variety of views about stress and coping mechanisms, with considerable individual differences. In the second phase, a more fine-grained quantitative analysis was conducted to assess training effectiveness. Results showed an increase in the proportion of coping strategies referred to by the experimental group post-training. This positive change remained at follow-up. The results of the content analysis and the outcome data have implications for staff training. © 2013 John Wiley & Sons Ltd.

Rock stress investigations

International Nuclear Information System (INIS)

Pahl, A.; Heusermann, St.; Braeuer, V.; Gloeggler, W.

1989-04-01

On the research project 'Rock Stress Mesurements' the BGR has developed and tested several methods for use in boreholes at a depth of 200 m. Indirect stress measurements using overcoring methods with BGR-probes and CSIR-triaxial cells as well as direct stress measurements using the hydraulic-fracturing method were made. To determine in-situ rock deformation behavior borehole deformation tests, using a BGR-dilatometer, were performed. Two types of the BGR-probe were applied: a four-component-probe to determine horizontal stresses and a five-component-probe to determine a quasi three-dimensional stress field. The first time a computer for data processing was installed in the borehole together with the BGR-probe. Laboratory tests on low cylinders were made to study the stress-deformation behavior. To validate and to interprete the measurement results some test methods were modelled using the finite-element method. The dilatometer-tests yielded high values of Young's modulus, whereas laboratory tests showed lower values with a distinct deformation anisotropy. Stress measurements with the BGR-probe yielded horizontal stresses being higher than the theoretical overburden pressure. These results are comparable to the results of the hydraulic fracturing tests, whereas stresses obtained with CSIR-triaxial cells are lower. The detailed geological mapping of the borehole indicated relationships between stress and geology. With regard to borehole depth different zones of rock structure joint frequency, joint orientation, and orientation of microfissures as well as stress magnitude, stress direction, and degree of deformation anisotropy could be distinguished. (author) 4 tabs., 76 figs., 31 refs

Arabidopsis AtDjA3 null mutant shows increased sensitivity to abscisic acid, salt, and osmotic stress in germination and postgermination stages

Directory of Open Access Journals (Sweden)

Silvia eSalas-Muñoz

2016-02-01

Full Text Available DnaJ proteins are essential co-chaperones involved in abiotic and biotic stress responses. Arabidopsis AtDjA3 gene encodes a molecular co-chaperone of 420 amino acids, which belongs to the J-protein family. In this study, we report the functional characterization of the AtDjA3 gene using the Arabidopsis knockout line designated j3 and the 35S::AtDjA3 overexpression lines. Loss of AtDjA3 function was associated with small seed production. In fact, j3 mutant seeds showed a reduction of 24% in seed weight compared to Col-0 seeds. Expression analysis showed that the AtDjA3 gene was modulated in response to NaCl, glucose, and abscisic acid. The j3 line had increased sensitivity to NaCl and glucose treatments in the germination and cotyledon development in comparison to parental Col-0. Furthermore, the j3 mutant line exhibited higher abscisic acid sensitivity in comparison to parental Col-0 and 35S::AtDjA3 overexpression lines. In addition, we examined the expression of ABI3 gene, which is a central regulator in ABA signalling, in j3 mutant and 35S::AtDjA3 overexpression lines. Under 5 μM ABA treatment at 24 h, j3 mutant seedlings displayed higher ABI3 expression, whereas in 35S::AtDjA3 overexpression lines, ABI3 gene expression was repressed. Taken together, these results demonstrate that the AtDjA3 gene is involved in seed development and abiotic stress tolerance.

Bidirectional crosstalk between stress-induced gastric ulcer and depression under chronic stress.

Directory of Open Access Journals (Sweden)

Shuang Zhang

Full Text Available Stress contributes to a variety of diseases and disorders such as depression and peptic ulcer. The present study aimed to investigate the correlation between stress ulcer and depression in pathogenesis and treatment by using chronic stress depression (CSD, chronic psychological stress ulcer (CPSU and water immersion restrain stress models in rats. Our data showed that the ulcer index of the animals after CSD exposure was significantly higher than that of controls. Depression-like behaviors were observed in rat after CPSU exposure. Fluoxetine hydrochloride significantly reduced the ulcer index of rats exposed to CPSU stress, while ranitidine inhibited depression-like behavior of the animals in CSD group. The ulcer index of rats administered with mifepristone after CPSU stress was markedly reduced compared to CPSU group, although there was no significant difference in the depression-like behavior between mifepristone-treated CSD group and naive controls. We also found that the rats exposed to CPSU or CSD stress displayed a lower level of corticosterone than naive controls, however, the acute stress (AS group showed an opposite result. Additionally, in order to study the relevance of H(2 receptors and depression, we treated the CSD group with cimetidine and famotidine respectively. The data showed that cimetidine inhibited depression-like behavior in CSD rats, and famotidine had no impact on depression. Overall our data suggested that the hypothalamic-pituitary-adrenal (HPA axis dysfunction may be the key role in triggering depression and stress ulcer. Acid-suppressing drugs and antidepressants could be used for treatment of depression and stress ulcer respectively. The occurrence of depression might be inhibited by blocking the central H(2 receptors.

Perturbation of parabolic kinetics resulting from the accumulation of stress in protective oxide layers

International Nuclear Information System (INIS)

Evans, H.E.; Norfolk, D.J.; Swan, T.

1978-01-01

A frequent observation in metal oxidation is the development of subparabolic kinetics, variously described as cubic or quartic. Although a number of detailed mechanisms have been proposed to account for this effect, none seem generally applicable. A model is presented of the oxidation process which is divorced from such restrictions. It is argued that deviations from parabolic behavior occur as a result of the concurrent development of stresses within the oxide. It is shown that the presence of stress fields can influence significantly the rate of transport of vacancy defects within the oxide such that tensile stresses produce positive deviations and compressive stresses, negative deviations from parabolic behavior. The model is applied in detail to Zircaloy-2 oxidation at 773 0 K. It is predicted that the kinetics should be insensitive to the oxygen potential of the environment and this has been confirmed by previous experimental work. 31 refs

Analysis of rock stress and rock stress measurements with application to Aespoe HRL

International Nuclear Information System (INIS)

Lundholm, Beatrice

2000-11-01

the opening where no influence from the openings can be expected. Since the magnitudes of the rock stresses differ between overcoring and hydraulic fracturing, some efforts have been made to find possible causes for this. The rock stresses when conducting overcoring gave higher values overall, which could be explained by high Poisson's ratios and a minor influence from the opening as the stress measurements might have been done in the disturbed zone. The high Poisson's ratio may depend on the stress-induced microcracks, which might be initiated during the overcoring of the cell, during the drilling of the pilot borehole, in which the cell is installed, and during biaxial testing. Statistical analysis showed that there is significant differences between the mean values of Poisson's ratio obtained from biaxial tests of cores containing the CSIRO HI-cell and the SSPB-cell. Poisson's ratio is about 0.34 for CSIRO HI-cell while the SSPB-cell gave a Poisson's ratio of 0.23. The analysis also showed that Young's modulus does not differ between the techniques. The modelling in FLAC was made to simulate the overcoring and biaxial testing. The result show that it is possible to obtain extensional strain in the core during overcoring if the major principal stress is perpendicular to the borehole axis. This may lead to microcracking occurring in the core causing high Poisson's ratio, which results in higher stresses. It can also be seen from the simulation of the biaxial testing that extensional strain is achieved even if the hollow core is not damaged during overcoring. The analyses using UDEC was made to study the effect of different properties of a discontinuity, such as the dip angle, Young's modulus, Poisson's ratio, density and the normal and shear stiffness. The analyses showed that an inclined discontinuity affects the stresses especially if sliding occurs. So, the dip angle does not solely, determine the amount of disturbance of the state of stress around a discontinuity

Iodine-induced stress corrosion cracking of fixed deflection stressed slotted rings of Zircaloy fuel cladding

International Nuclear Information System (INIS)

Sejnoha, R.; Wood, J.C.

1978-01-01

Stress corrosion cracking of Zircaloy fuel cladding by fission products is thought to be an important mechanism influencing power ramping defects of water-reactor fuels. We have used the fixed-deflection stressed slotted-ring technique to demonstrate cracking. The results show both the sensitivity and limitations of the stressed slotted-ring method in determining the responses of tubing to stress corrosion cracking. They are interpreted in terms of stress relaxation behavior, both on a microscopic scale for hydrogen-induced stress-relief and on a macroscopic scale for stress-time characteristics. Analysis also takes account of nonuniform plastic deformation during loading and residual stress buildup on unloading. 27 refs

Elaboration of the Environmental Stress Hypothesis–Results from a Population-Based 6-Year Follow-Up

Science.gov (United States)

Wagner, Matthias; Jekauc, Darko; Worth, Annette; Woll, Alexander

2016-01-01

The aim of this paper was to contribute to the elaboration of the Environmental Stress Hypothesis framework by testing eight hypotheses addressing the direct impact of gross motor coordination problems in elementary-school on selected physical, behavioral and psychosocial outcomes in adolescence. Results are based on a longitudinal sample of 940 participants who were (i) recruited as part of a population-based representative survey on health, physical fitness and physical activity in childhood and adolescence, (ii) assessed twice within 6 years, between the ages of 6 and 10 years old as well as between the ages of 12 and 16 years old (Response Rate: 55.9%) and (iii) classified as having gross motor coordination problems (N = 115) or having no gross motor coordination problems (N = 825) at baseline. Motor tests from the Körperkoordinationstest, measures of weight and height, a validated physical activity questionnaire as well as the Strength and Difficulties Questionnaire were conducted. Data were analyzed by use of binary logistic regressions. Results indicated that elementary-school children with gross motor coordination problems show a higher risk of persistent gross motor coordination problems (OR = 7.99, p gross motor coordination problems. However, elementary-school children with gross motor coordination problems did not show a significantly higher risk of peer problems (OR = 1.35, p = 0.164) or diminished prosocial behavior (OR = 1.90, p = 0.168) in adolescence, respectively in comparison to elementary-school children without gross motor coordination problems. This study is the first to provide population-based longitudinal data ranging from childhood to adolescence in the context of the Environmental Stress Hypothesis which can be considered a substantial methodological progress. In summary, gross motor coordination problems represent a serious issue for a healthy transition from childhood to adolescence which substantiates respective early movement

Borehole Breakout Growth and In-Situ Stress Orientation in the Central Scandinavian Caledonides: Results from the Cosc-1 Borehole

Science.gov (United States)

Wenning, Q.; Zappone, A.; Berthet, T.; Ask, M. V. S.; Rosberg, J. E.; Almqvist, B. S. G.

2017-12-01

Borehole breakouts are often assumed to form near instantaneously due to stress perturbations around boreholes after the rock mass was removed. Recent observations in sediments [e.g., Moore et al., 2011] and crystalline rocks [e.g., Berard and Cornet, 2003], as well as numerical modelling results [e.g., Schoenball et al., 2014], suggest that there are cases in which borehole breakout grows radially over time, forcing us to reconsider subsurface stress estimation. These observations are rare due to drilling difficulties (i.e., cementing and casing the borehole after drilling), often only allowing a single image logging campaign. In 2014, the Collisional Orogeny in the Scandinavian Caledonides deep scientific borehole (COSC-1) was drilled to a depth of 2.5 km. To date the borehole is open and uncased, allowing two acoustic televiewer logging campaigns, with more than one year between campaigns. The borehole is still available for supplementary data collactions. These logs provide detailed images along the full length of the 2.5 km deep borehole with 1.6 km of overlapping logs for breakout and drilling induced tensile fracture analysis. The results show from the sparse occurrence of breakouts and drilling induced tensile fractures a NW-SE average maximum horizontal stress direction, consistent with the general trend in Scandinavia. The unique acquisition of image logs in two successions allows for analysis of time-dependent borehole deformation, indicating that six breakout zones have crept, both along the borehole axis and radially (up to 20° growth) around the borehole. While some breakouts have grown, the formation of new breakouts has not occurred. The occurrence of breakouts and their growth appear to be independent of lithology. The observed growth after the second logging campaign suggests that under conditions where the stress exceeded the strength of the rock, the resulting breakout causes perturbations in the stresses around the borehole in the near

Effects of dietary extra-virgin olive oil on oxidative stress resulting from exhaustive exercise in rat skeletal muscle: a morphological study.

Science.gov (United States)

Musumeci, Giuseppe; Maria Trovato, Francesca; Imbesi, Rosa; Castrogiovanni, Paola

2014-01-01

Physical exercise induces oxidative stress through production of reactive oxygen species and can cause damage to muscle tissue. Oxidative stress, resulting from exhaustive exercise is high and improvement of antioxidant defenses of the body may ameliorate damage caused by free radicals. Extra-virgin olive oil is widely considered to possess anti-oxidative properties. The aim of this study was to determine if extra-virgin olive oil improved the adaptive responses in conditions of oxidative stress. Twenty-four 12-week-old male Sprague-Dawley rats were divided in three groups: (1) rats fed with standard chow and not subjected to physical exercise; (2) rats fed with standard chow and subjected to exhaustive exercise; (3) rats fed with a diet rich in oleic acid, the major component of extra-virgin olive oil, and subjected to exhaustive exercise. Exhaustive exercise consisted of forced running in a five-lane 10° inclined treadmill at a speed of 30 m/min for 70-75 min. We studied some biomarkers of oxidative stress and of antioxidant defenses, histology and ultrastructure of the Quadriceps femoris muscle (Rectus femoris). We observed that, in rats of group 3, parameters indicating oxidative stress such as hydroperoxides and thiobarbituric acid-reactive substances decreased, parameters indicating antioxidant defenses of the body such as non-enzymatic antioxidant capacity and Hsp70 expression increased, and R. femoris muscle did not show histological and ultrastructural alterations. Results of this study support the view that extra-virgin olive oil can improve the adaptive response of the body in conditions of oxidative stress. Copyright © 2013 Elsevier GmbH. All rights reserved.

Tripod sigma: results of a pro-active work stress-survey

NARCIS (Netherlands)

Nelemans, R.; Wiezer, N.; Vaas, F.; Gort, J.; Groeneweg, J.

2003-01-01

Work related stress is an important causes of disability and absenteeism. TNO Work and Employment has developed an instrument, called Tripod Sigma, that identifies risks to work stress and provides tools for remedying these risks. The Tripod Sigma model is developed analogous to the Tripod

Development of a New Technique to Assess Susceptibility to Predation Resulting from Sublethal Stresses (Indirect Mortality)

Energy Technology Data Exchange (ETDEWEB)

Cada, G.F.

2003-08-25

escape behavior yielded results comparable to traditional predator preference tests. Because this fish behavior test is simpler and quicker to conduct than predator preference tests, it shows promise as a useful technique for assessing indirect mortality resulting from sublethal stresses.

Thermal stress in flexible interdigital transducers with anisotropic electroactive cellulose substrates

Science.gov (United States)

Yoon, Sean J.; Kim, Jung Woong; Kim, Hyun Chan; Kang, Jinmo; Kim, Jaehwan

2017-12-01

Thermal stress in flexible interdigital transducers a reliability concern in the development of flexible devices, which may lead to interface delamination, stress voiding and plastic deformation. In this paper, a mathematical model is presented to investigate the effect of material selections on the thermal stress in interdigital transducers. We modified the linear relationships in the composite materials theory with the effect of high curvature, anisotropic substrate and small substrate thickness. We evaluated the thermal stresses of interdigital transducers, fabricated with various electrodes, insulators and substrate materials for the comparison. The results show that, among various insulators, organic polymer developed the highest stress level while oxide showed the lowest stress level. Aluminium shows a higher stress level and curvature as an electrode than gold. As substrate materials, polyimide and electroactive cellulose show similar stress levels except the opposite sign convention to each other. Polyimide shows positive curvatures while electroactive cellulose shows negative curvatures, which is attributed to the stress and thermal expansion state of the metal/insulator composite. The results show that the insulator is found to be responsible for the confinement across the metal lines while the substrate is responsible for the confinement along the metal lines.

Comfort food is comforting to those most stressed: evidence of the chronic stress response network in high stress women.

Science.gov (United States)

Tomiyama, A Janet; Dallman, Mary F; Epel, Elissa S

2011-11-01

Chronically stressed rodents who are allowed to eat calorie-dense "comfort" food develop greater mesenteric fat, which in turn dampens hypothalamic-pituitary-adrenocortical (HPA) axis activity. We tested whether similar relations exist in humans, at least cross-sectionally. Fifty-nine healthy premenopausal women were exposed to a standard laboratory stressor to examine HPA response to acute stress and underwent diurnal saliva sampling for basal cortisol and response to dexamethasone administration. Based on perceived stress scores, women were divided into extreme quartiles of low versus high stress categories. We found as hypothesized that the high stress group had significantly greater BMI and sagittal diameter, and reported greater emotional eating. In response to acute lab stressor, the high stress group showed a blunted cortisol response, lower diurnal cortisol levels, and greater suppression in response to dexamethasone. These cross-sectional findings support the animal model, which suggests that long-term adaptation to chronic stress in the face of dense calories result in greater visceral fat accumulation (via ingestion of calorie-dense food), which in turn modulates HPA axis response, resulting in lower cortisol levels. Copyright © 2011 Elsevier Ltd. All rights reserved.

Does Stress Result in You Exercising Less? Or Does Exercising Result in You Being Less Stressed? Or Is It Both? Testing the Bi-directional Stress-Exercise Association at the Group and Person (N of 1) Level.

Science.gov (United States)

Burg, Matthew M; Schwartz, Joseph E; Kronish, Ian M; Diaz, Keith M; Alcantara, Carmela; Duer-Hefele, Joan; Davidson, Karina W

2017-12-01

Psychosocial stress contributes to heart disease in part by adversely affecting maintenance of health behaviors, while exercise can reduce stress. Assessing the bi-directional relationship between stress and exercise has been limited by lack of real-time data and theoretical and statistical models. This lack may hinder efforts to promote exercise maintenance. We test the bi-directional relationship between stress and exercise using real-time data for the average person and the variability-individual differences-in this relationship. An observational study was conducted within a single cohort randomized controlled experiment. Healthy young adults, (n = 79) who reported only intermittent exercise, completed 12 months of stress monitoring by ecological momentary assessment (at the beginning of, end of, and during the day) and continuous activity monitoring by Fitbit. A random coefficients linear mixed model was used to predict end-of-day stress from the occurrence/non-occurrence of exercise that day; a logistic mixed model was used to predict the occurrence/non-occurrence of exercise from ratings of anticipated stress. Separate regression analyses were also performed for each participant. Sensitivity analysis tested all models, restricted to the first 180 days of observation (prior to randomization). We found a significant average inverse (i.e., negative) effect of exercise on stress and of stress on exercise. There was significant between-person variability. Of N = 69, exercise was associated with a stress reduction for 15, a stress increase for 2, and no change for the remainder. We also found that an increase in anticipated stress reported the previous night or that morning was associated with a significant 20-22% decrease (OR = 0.78-0.80) in the odds of exercising that day. Of N = 69, this increase in stress reduced the likelihood of exercise for 17, increased the odds for 1, and had no effect for the remainder. We were unable to identify psychosocial

Smaller Hippocampal Volume in Posttraumatic Stress Disorder : A Multisite ENIGMA-PGC Study: Subcortical Volumetry Results From Posttraumatic Stress Disorder Consortia

NARCIS (Netherlands)

Logue, Mark W.; van Rooij, Sanne J H; Dennis, Emily L.; Davis, Sarah L.; Hayes, Jasmeet P.; Stevens, Jennifer S.; Densmore, Maria; Haswell, Courtney C.; Ipser, Jonathan; Koch, Saskia B.J.; Korgaonkar, Mayuresh; Lebois, Lauren A.M.; Peverill, Matthew; Baker, Justin T.; Boedhoe, Premika S W; Frijling, Jessie L.; Gruber, Staci A.; Harpaz-Rotem, Ilan; Jahanshad, Neda; Koopowitz, Sheri; Levy, Ifat; Nawijn, Laura; O'Connor, Lauren; Olff, Miranda; Salat, David H.; Sheridan, Margaret A.; Spielberg, Jeffrey M.; van Zuiden, Mirjam; Winternitz, Sherry R.; Wolff, Jonathan D.; Wolf, Erika J.; Wang, Xin; Wrocklage, Kristen; Abdallah, Chadi G.; Bryant, Richard A.; Geuze, Elbert; Jovanovic, Tanja; Kaufman, Milissa L.; King, Anthony P.; Krystal, John H.; Lagopoulos, Jim; Bennett, Maxwell; Lanius, Ruth; Liberzon, Israel; McGlinchey, Regina E.; McLaughlin, Katie A.; Milberg, William P.; Miller, Mark W.; Ressler, Kerry J; Veltman, Dick J.; Stein, Dan J; Thomaes, Kathleen; Thompson, Paul M.; Morey, Rajendra A.

2018-01-01

Background Many studies report smaller hippocampal and amygdala volumes in posttraumatic stress disorder (PTSD), but findings have not always been consistent. Here, we present the results of a large-scale neuroimaging consortium study on PTSD conducted by the Psychiatric Genomics Consortium

Psychological stress in undergraduate dental students: baseline results from seven European dental schools.

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Humphris, Gerry; Blinkhorn, Andy; Freeman, Ruth; Gorter, Ronald; Hoad-Reddick, Gillian; Murtomaa, Heikki; O'Sullivan, Robin; Splieth, Christian

2002-02-01

To determine the degree of psychological distress, the experience of emotional exhaustion, and the extent of stress associated with course work in dental students and to compare these measurements among seven European dental schools. Multi-centred survey. Dental Schools at Amsterdam, Belfast, Cork, Greifswald, Helsinki, Liverpool and Manchester. 333 undergraduate first-year dental students. General Health Questionnaire (GHQ12), Maslach Burnout Inventory (MBI), Dental Environment Stress Questionnaire (DES), demographic variables. Questionnaire administered to all students attending first year course. Completed questionnaires sent to central office for processing. Seventy-nine percent of the sampled students responded. Over a third of the students (36%) reported significant psychological distress (morbidity) at the recommended cut-off point (>3 on GHQ). These scores were similar to those reported for medical undergraduates. Twenty-two percent recorded comparatively high scores on emotional exhaustion. A wide variation in these 2 measurements was found across schools (p'sStress levels indicated by the DES were less variable (p>0.5). Some evidence showed that contact with patients and the level of support afforded by living at home may be protective. Higher than expected levels of emotional exhaustion were found in a large sample of first-year undergraduate dental students in Europe.

Effects of stress or infection on rat behavior show robust reversals due to environmental disturbance [version 2; referees: 2 approved

Directory of Open Access Journals (Sweden)

Samira Abdulai-Saiku

2018-01-01

Full Text Available Background: The behavior of animals is intricately linked to the environment; a relationship that is often studied in laboratory conditions by using environmental perturbations to study biological mechanisms underlying the behavioral change.  Methods: This study pertains to two such well-studied and well-replicated perturbations, i.e., stress-induced anxiogenesis and Toxoplasma gondii -induced loss of innate fear. Here, we demonstrate that behavioral outcomes of these experimental manipulations are contingent upon the ambient quality of the wider environment where animal facilities are situated. Results: During late 2014 and early 2015, a building construction project started adjacent to our animal facility. During this phase, we observed that maternal separation stress caused anxiolysis, rather than historically observed anxiogenesis, in laboratory rats. We also found that Toxoplasma gondii infection caused an increase, rather than historically observed decrease, in innate aversion to predator odors in rats. Conclusion: These observations suggest that effects of stress and Toxoplasma gondii are dependent on variables in the environment that often go unreported in the published literature.

Main results of BN-600 reactor stress-strain state investigations

International Nuclear Information System (INIS)

Panov, V.A.

1983-01-01

The development of BN-600 fast reactor plant needed the solution of a series of complex engineering problems including ones for confirming integrity of the most vital structural components. The particular attention was given to the main vessel since reactor availability end safe operation of the plant as a whole depend on vessel strength end integrity. The present report deals with the main results of theoretical and experimental investigations of the stress-strain state of BN-600 reactor vessel carried out during design, start-up and initial bringing the reactor to power

Prenatal Stress as a Risk-and an Opportunity-Factor.

Science.gov (United States)

Hartman, Sarah; Freeman, Sara M; Bales, Karen L; Belsky, Jay

2018-04-01

Two separate lines of research indicate (a) that prenatal stress is associated with heightened behavioral and physiological reactivity and (b) that these postnatal phenotypes are associated with increased susceptibility to both positive and negative developmental experiences. Therefore, prenatal stress may increase sensitivity to the rearing environment. We tested this hypothesis by manipulating prenatal stress and rearing-environment quality, using a cross-fostering paradigm, in prairie voles. Results showed that prenatally stressed voles, as adults, displayed the highest behavioral and physiological reactivity when cross-fostered to low-contact (i.e., low-quality) rearing but the lowest behavioral and physiological reactivity when cross-fostered to high-contact (i.e., high-quality) rearing; non-prenatally stressed voles showed no effect of rearing condition. Additionally, while neither prenatal stress nor rearing condition affected oxytocin receptor binding, prenatally stressed voles cross-fostered to high-contact rearing showed the highest vasopressin-1a receptor binding in the amygdala. Results indicate that prenatal stress induces greater environmental sensitivity, making it both a risk and an opportunity factor.

Coupling effects of chemical stresses and external mechanical stresses on diffusion

International Nuclear Information System (INIS)

Xuan Fuzhen; Shao Shanshan; Wang Zhengdong; Tu Shantung

2009-01-01

Interaction between diffusion and stress fields has been investigated extensively in the past. However, most of the previous investigations were focused on the effect of chemical stress on diffusion due to the unbalanced mass transport. In this work, the coupling effects of external mechanical stress and chemical stress on diffusion are studied. A self-consistent diffusion equation including the chemical stress and external mechanical stress gradient is developed under the framework of the thermodynamic theory and Fick's law. For a thin plate subjected to unidirectional tensile stress fields, the external stress coupled diffusion equation is solved numerically with the help of the finite difference method for one-side and both-side charging processes. Results show that, for such two types of charging processes, the external stress gradient will accelerate the diffusion process and thus increase the value of concentration while reducing the magnitude of chemical stress when the direction of diffusion is identical to that of the stress gradient. In contrast, when the direction of diffusion is opposite to that of the stress gradient, the external stress gradient will obstruct the process of solute penetration by decreasing the value of concentration and increasing the magnitude of chemical stress. For both-side charging process, compared with that without the coupling effect of external stress, an asymmetric distribution of concentration is produced due to the asymmetric mechanical stress field feedback to diffusion.

Stress, breakfast cereal consumption and cortisol.

Science.gov (United States)

Smith, A P

2002-04-01

Recent research has shown that regular consumption of breakfast cereal is associated with lower stress levels and reports of better physical and mental health. The present study examined this issue using an objective indicator of stress, salivary cortisol. The results showed that stress was associated with higher cortisol levels and daily consumption of breakfast cereal was associated with lower cortisol levels. Although it was not possible to rule out all the alternative explanations of the association between breakfast cereal consumption and cortisol, analyses did show that the effect could not be accounted for by general health or nutritional status. The effects of breakfast cereal consumption and stress were also independent, which shows that the effects of breakfast found here cannot be due to stress buffering. Further research manipulating the nutrient content of the breakfast cereal is now required to provide further information about the mechanisms underlying this effect.

Evaluation of stress intensity factors due to welding residual stresses for circumferential cracked pipes

International Nuclear Information System (INIS)

Oh, Chang-Young; Kim, Yun-Jae; Oh, Young-Jin; Kim, Jong-Sung; Song, Tae-Kwang; Kim, Yong-Beum

2013-01-01

To investigate the applicability of existing methods to estimate stress intensity factors due to welding residual stresses, comparisons with finite element (FE) solutions are made for two types of generic welding residual stress profiles, generated by simulating repair welds. It is found that fitting residual stresses over the crack depth using third-order polynomials gives good estimates of stress intensity factors but fitting over the entire thickness can result in inaccurate estimates even with fourth-order polynomials. Noting that welding residual stresses are often determined from FE analyses, linearization of residual stresses to estimate stress intensity factors is proposed. Comparison with FE solutions shows good agreements. -- Highlights: ► Applicability of K estimation methods is investigated for welding residual stresses. ► Two types of generic residual stress profiles with repair welds are considered. ► Fitting residual stresses over the crack depth gives good estimates of K. ► A method to estimate K by linearising residual stress profiles is proposed

On the time course of lexical stress priming in speech production: Behavioral and ERPs evidence from a free-stress language.

Science.gov (United States)

Sulpizio, Simone; Vespignani, Francesco; Job, Remo

2016-10-01

The goal of the present research was to study the time course of lexical stress encoding in a free-stress language with unpredictable stress. To this aim we measured event-related brain potentials (ERPs) during lexical priming. Participants named pictures bearing either the dominant or non-dominant stress pattern, and preceded by either a congruent or an incongruent word prime (e.g., CInema-FRAgola'cinema-strawberry' vs. benZIna-FRAgola'petrol-strawberry'). Behavioral results show that participants were slower in naming targets that had the same stress pattern as the prime, and were also faster in producing words with the dominant stress pattern in the language. The electrophysiological results show that both the effects are compatible with the time course of phonological encoding in speech production. Surprisingly, a dominant stress effect occurred in the ERPs elicited by the primes, with a larger positivity for non-dominant stress words in a 150-250ms time-window. The pattern of results indicates that during speech production: a) the system is sensitive to the stress patterns distribution; b) the automatic pre-activation of a metrical frame may interfere with the phonological encoding of a to-be-uttered word. Copyright © 2016 Elsevier B.V. All rights reserved.

Hydroxyurea-Induced Replication Stress

Directory of Open Access Journals (Sweden)

Kenza Lahkim Bennani-Belhaj

2010-01-01

Full Text Available Bloom's syndrome (BS displays one of the strongest known correlations between chromosomal instability and a high risk of cancer at an early age. BS cells combine a reduced average fork velocity with constitutive endogenous replication stress. However, the response of BS cells to replication stress induced by hydroxyurea (HU, which strongly slows the progression of replication forks, remains unclear due to publication of conflicting results. Using two different cellular models of BS, we showed that BLM deficiency is not associated with sensitivity to HU, in terms of clonogenic survival, DSB generation, and SCE induction. We suggest that surviving BLM-deficient cells are selected on the basis of their ability to deal with an endogenous replication stress induced by replication fork slowing, resulting in insensitivity to HU-induced replication stress.

Modelling of loading, stress relaxation and stress recovery in a shape memory polymer.

Science.gov (United States)

Sweeney, J; Bonner, M; Ward, I M

2014-09-01

A multi-element constitutive model for a lactide-based shape memory polymer has been developed that represents loading to large tensile deformations, stress relaxation and stress recovery at 60, 65 and 70°C. The model consists of parallel Maxwell arms each comprising neo-Hookean and Eyring elements. Guiu-Pratt analysis of the stress relaxation curves yields Eyring parameters. When these parameters are used to define the Eyring process in a single Maxwell arm, the resulting model yields at too low a stress, but gives good predictions for longer times. Stress dip tests show a very stiff response on unloading by a small strain decrement. This would create an unrealistically high stress on loading to large strain if it were modelled by an elastic element. Instead it is modelled by an Eyring process operating via a flow rule that introduces strain hardening after yield. When this process is incorporated into a second parallel Maxwell arm, there results a model that fully represents both stress relaxation and stress dip tests at 60°C. At higher temperatures a third arm is required for valid predictions. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

Habitat disturbance results in chronic stress and impaired health status in forest-dwelling paleotropical bats.

Science.gov (United States)

Seltmann, Anne; Czirják, Gábor Á; Courtiol, Alexandre; Bernard, Henry; Struebig, Matthew J; Voigt, Christian C

2017-01-01

Anthropogenic habitat disturbance is a major threat to biodiversity worldwide. Yet, before population declines are detectable, individuals may suffer from chronic stress and impaired immunity in disturbed habitats, making them more susceptible to pathogens and adverse weather conditions. Here, we tested in a paleotropical forest with ongoing logging and fragmentation, whether habitat disturbance influences the body mass and immunity of bats. We measured and compared body mass, chronic stress (indicated by neutrophil to lymphocyte ratios) and the number of circulating immune cells between several bat species with different roost types living in recovering areas, actively logged forests, and fragmented forests in Sabah, Malaysia. In a cave-roosting species, chronic stress levels were higher in individuals from fragmented habitats compared with conspecifics from actively logged areas. Foliage-roosting species showed a reduced body mass and decrease in total white blood cell counts in actively logged areas and fragmented forests compared with conspecifics living in recovering habitats. Our study highlights that habitat disturbance may have species-specific effects on chronic stress and immunity in bats that are potentially related to the roost type. We identified foliage-roosting species as particularly sensitive to forest habitat deterioration. These species may face a heightened extinction risk in the near future if anthropogenic habitat alterations continue.

Neuropeptide Y and Stress

Directory of Open Access Journals (Sweden)

Murat Gulsun

2012-03-01

Full Text Available The neurobiological aspects of stress and coping skills has been the focus of interest for many researchers. Some of the studies has shown that there is a significant relationship among genetically variables, stress response and life events. Neuropeptide Y is one of the systems regulating the stress response. Under the prolonged or repeated trauma neuropeptide Y is released from the brain's key areas. This system shows different levels of functioning in individuals with different levels of resilience. There is particular interest in the variations of genes that encode stress-sensitive signaling molecules during gene-environment interaction. This condition may contribute to susceptibility of stress or stress resilience. Neuropeptide Y system plays a key role in the adaptation to behavioral stress. The reduced levels of neuropeptide Y have also been observed in treatment-resistant depression and posttraumatic stress disorder. Lower level of neuropeptide Y expression and dysfunctional neuropeptide Y system in response to stress and resulting decreased stress resilience could increase susceptibility to stress-related disorders.

Exploring and reducing stress in young restaurant workers: results of a randomized field trial.

Science.gov (United States)

Petree, Robyn D; Broome, Kirk M; Bennett, Joel B

2012-01-01

Young adult restaurant workers face the dual stressors of work adjustment and managing personal responsibilities. We assessed a new psychosocial/health promotion training designed to reduce these stressors in the context of restaurant work. DESIGN . A cluster-randomized trial of a training program, with surveys administered approximately 2 weeks before training and both 6 and 12 months after training. A national restaurant chain. A total of 947 restaurant workers in 28 restaurants. Personal stress, exposure to problem coworkers, and personal and job characteristics. Team Resilience (TR) is an interactive program for stress management, teamwork, and work-life balance. TR focuses on "five Cs" of resilience: compassion, commitment, centering, community, and confidence. ANALYSIS . Mixed-model (multilevel) analysis of covariances. Compared with workers in control stores, workers in TR-trained stores showed significant reductions over time in exposure to problem coworkers (F[2, 80.60]  =  4.48; p  =  .01) and in personal stress (F[2, 75.28]  =  6.12; p  =  .003). The TR program may help young workers who face the challenges of emerging adulthood and work-life balance.

Response of the diatom Phaeodactylum tricornutum to photooxidative stress resulting from high light exposure.

Directory of Open Access Journals (Sweden)

Nuno Domingues

Full Text Available The response of microalgae to photooxidative stress resulting from high light exposure is a well-studied phenomenon. However, direct analyses of photosystem II (PSII D1 protein (the main target of photoinhibition in diatoms are scarce. In this study, the response of the diatom model species Phaeodactylum tricornutum to short-term exposure to high light was examined and the levels of D1 protein determined immunochemically. Low light (LL acclimated cells (40 µmol photons m(-2 s(-1 subjected to high light (HL, 1,250 µmol photons m(-2 s(-1 showed rapid induction of non-photochemical quenching (NPQ and ca. 20-fold increase in diatoxanthin (DT concentration. This resulted from the conversion of diadinoxanthin (DD to DT through the activation of the DD-cycle. D1 protein levels under LL decreased about 30% after 1 h of the addition of lincomycin (LINC, a chloroplast protein synthesis inhibitor, showing significant D1 degradation and repair under low irradiance. Exposure to HL lead to a 3.2-fold increase in D1 degradation rate, whereas average D1 repair rate was 1.3-x higher under HL than LL, leading to decreased levels of D1 protein under HL. There were significant effects of both HL and LINC on P. tricornutum maximum quantum yield of PSII (F(v/F(m, showing a reduction of active PSII reaction centres. Partial recovery of F(v/F(m in the dark demonstrates the photosynthetic resilience of this diatom to changes in the light regime. P. tricornutum showed high allocation of total protein to D1 and an active D1-repair cycle to limit photoinhibition.

Stress 'deafness' in a language with fixed word stress: an ERP study on Polish

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Ulrike eDomahs

2012-11-01

Full Text Available The aim of the present contribution was to examine the factors influencing the prosodic processing in a language with predictable word stress. For Polish, a language with fixed penultimate stress but several well-defined exceptions, difficulties in the processing and representation of prosodic information have been reported (e.g., Peperkamp & Dupoux, 2002. The present study utilized event-related potentials (ERPs to investigate the factors influencing prosodic processing in Polish. These factors are i the predictability of stress and ii the prosodic structure in terms of metrical feet. Polish native speakers were presented with correctly and incorrectly stressed Polish words and instructed to judge the correctness of the perceived stress patterns. For each stress violation an early negativity was found which was interpreted as reflection of an error-detection mechanism, and in addition exceptional stress patterns (= antepenultimate stress and post-lexical (= initial stress evoked a task-related positivity effect (P300 whose amplitude and latency is correlated with the degree of anomaly and deviation from an expectation. Violations involving the default (= penultimate stress in contrast did not produce such an effect. This asymmetrical result is interpreted to reflect that Polish native speakers are less sensitive to the default pattern than to the exceptional or post-lexical patterns. Behavioral results are orthogonal to the electrophysiological results showing that Polish speakers had difficulties to reject any kind of stress violation. Thus, on a meta-linguistic level Polish speakers appeared to be stress-‘deaf’ for any kind of stress manipulation, whereas the neural reactions differentiate between the default and lexicalized patterns.

Do I just look stressed or am I stressed? Work-related stress in a sample of Italian employees.

Science.gov (United States)

Giorgi, Gabriele; Leon-Perez, Jose M; Cupelli, Vincenzo; Mucci, Nicola; Arcangeli, Giulio

2014-01-01

Work-related stress is becoming a significant problem in Italy and it is therefore essential to advance the theory and methodology required to detect this phenomenon at work. Thus, the aim of this paper is to propose a new method for evaluating stress at work by measuring the discrepancies between employees' perceptions of stress and their leaders' evaluation of the stress of their subordinates. In addition, a positive impression scale was added to determine whether workers might give socially desirable responses in organizational diagnosis. Over 1,100 employees and 200 leaders within several Italian organizations were involved in this study. Structural equation modeling was used to test such new method for evaluating stress in a model of stress at work that incorporates relationships among individual (positive impression), interpersonal (workplace bullying) and organizational factors (working conditions, welfare culture, training). Results showed that the leaders' capacity to understand subordinates' stress is associated with subordinates' psychological well-being since higher disagreement between self and leaders' ratings was related to lower well-being. We discuss the implications of healthy leadership for the development of healthy organizations.

When does stress help or harm? The effects of stress controllability and subjective stress response on stroop performance.

Science.gov (United States)

Henderson, Roselinde K; Snyder, Hannah R; Gupta, Tina; Banich, Marie T

2012-01-01

The ability to engage in goal-directed behavior despite exposure to stress is critical to resilience. Questions of how stress can impair or improve behavioral functioning are important in diverse settings, from athletic competitions to academic testing. Previous research suggests that controllability is a key factor in the impact of stress on behavior: learning how to control stressors buffers people from the negative effects of stress on subsequent cognitively demanding tasks. In addition, research suggests that the impact of stress on cognitive functioning depends on an individual's response to stressors: moderate responses to stress can lead to improved performance while extreme (high or low) responses can lead to impaired performance. The present studies tested the hypothesis that (1) learning to behaviorally control stressors leads to improved performance on a test of general executive functioning, the color-word Stroop, and that (2) this improvement emerges specifically for people who report moderate (subjective) responses to stress. Experiment 1: Stroop performance, measured before and after a stress manipulation, was compared across groups of undergraduate participants (n = 109). People who learned to control a noise stressor and received accurate performance feedback demonstrated reduced Stroop interference compared with people exposed to uncontrollable noise stress and feedback indicating an exaggerated rate of failure. In the group who learned behavioral control, those who reported moderate levels of stress showed the greatest reduction in Stroop interference. In contrast, in the group exposed to uncontrollable events, self-reported stress failed to predict performance. Experiment 2: In a second sample (n = 90), we specifically investigated the role of controllability by keeping the rate of failure feedback constant across groups. In the group who learned behavioral control, those who reported moderate levels of stress showed the greatest Stroop

[Spanish adaptation of the Stress Manifestations Scale of the Student Stress Inventory (SSI-SM)].

Science.gov (United States)

Escobar Espejo, Milagros; Blanca, María J; Fernández-Baena, F Javier; Trianes Torres, María Victoria

2011-08-01

The aim of the present study was to translate into Spanish and to describe the psychometric properties of the Stress Manifestations Scale of the Student Stress Inventory (SSI-SM), developed by Fimian, Fastenau, Tashner and Cross to identify the main manifestations of stress in adolescents. The scale was applied to a sample of 1,002 pupils from years one and two of Secondary Education. The paper reports the factor structure, an item analysis, the internal consistency, differences by sex and academic year, external evidence of validity, and norms for scoring the scale. The results reveal a factor structure based on three first-order factors (emotional manifestations, physiological manifestations and behavioural manifestations) and one second-order factor (indicative of stress manifestations). In terms of external validity, there was a positive association with measures of perceived stress, aggressiveness, internalized/externalized symptoms, and a negative association with life satisfaction. The results show that the scale is an adequate tool for evaluating stress manifestations in adolescents.

Psychosocial versus physiological stress – meta-analyses on deactivations and activations of the neural correlates of stress reactions

Science.gov (United States)

Kogler, Lydia; Mueller, Veronika I.; Chang, Amy; Eickhoff, Simon B.; Fox, Peter T.; Gur, Ruben C.; Derntl, Birgit

2015-01-01

Stress is present in everyday life in various forms and situations. Two stressors frequently investigated are physiological and psychosocial stress. Besides similar subjective and hormonal responses, it has been suggested that they also share common neural substrates. The current study used activation-likelihood-estimation meta-analysis to test this assumption by integrating results of previous neuroimaging studies on stress processing. Reported results are cluster-level FWE corrected. The inferior frontal gyrus (IFG) and the anterior insula (AI) were the only regions that demonstrated overlapping activation for both stressors. Analysis of physiological stress showed consistent activation of cognitive and affective components of pain processing such as the insula, striatum, or the middle cingulate cortex. Contrarily, analysis across psychosocial stress revealed consistent activation of the right superior temporal gyrus and deactivation of the striatum. Notably, parts of the striatum appeared to be functionally specified: the dorsal striatum was activated in physiological stress, whereas the ventral striatum was deactivated in psychosocial stress. Additional functional connectivity and decoding analyses further characterized this functional heterogeneity and revealed higher associations of the dorsal striatum with motor regions and of the ventral striatum with reward processing. Based on our meta-analytic approach, activation of the IFG and the AI seems to indicate a global neural stress reaction. While physiological stress activates a motoric fight-or-flight reaction, during psychosocial stress attention is shifted towards emotion regulation and goal-directed behavior, and reward processing is reduced. Our results show the significance of differentiating physiological and psychosocial stress in neural engagement. Furthermore, the assessment of deactivations in addition to activations in stress research is highly recommended. PMID:26123376

Welding stresses

International Nuclear Information System (INIS)

Poirier, J.; Barbe, B.; Jolly, N.

1976-01-01

The aim is to show how internal stresses are generated and to fix the orders of magnitude. A realistic case, the vertical welding of thick plates free to move one against the other, is described and the deformations and stresses are analyzed. The mathematical model UEDA, which accounts for the elastic modulus, the yield strength and the expansion coefficient of the metal with temperature, is presented. The hypotheses and results given apply only to the instantaneous welding of a welded plate and to a plate welded by a moving electrode [fr

Effectiveness of stress release geometries on reducing residual stress in electroforming metal microstructure

Science.gov (United States)

Song, Chang; Du, Liqun; Zhao, Wenjun; Zhu, Heqing; Zhao, Wen; Wang, Weitai

2018-04-01

Micro electroforming, as a mature micromachining technology, is widely used to fabricate metal microdevices in micro electro mechanical systems (MEMS). However, large residual stress in the local positions of the micro electroforming layer often leads to non-uniform residual stress distributions, dimension accuracy defects and reliability issues during fabrication of the metal microdevice. To solve this problem, a novel design method of presetting stress release geometries in the topological structure of the metal microstructure is proposed in this paper. First, the effect of stress release geometries (circular shape, annular groove shape and rivet shape) on the residual stress in the metal microstructure was investigated by finite element modeling (FEM) analysis. Two evaluation parameters, stress concentration factor K T and stress non-uniformity factor δ were calculated. The simulation results show that presetting stress release geometries can effectively reduce and homogenize the residual stress in the metal microstructures were measured metal microstructure. By combined use with stress release geometries of annular groove shape and rivet shape, the stress concentration factor K T and the stress non-uniformity factor δ both decreased at a maximum of 49% and 53%, respectively. Meanwhile, the average residual stress σ avg decreased at a maximum of 20% from  -292.4 MPa to  -232.6 MPa. Then, micro electroforming experiments were carried out corresponding to the simulation models. The residual stresses in the metal microstructures were measured by micro Raman spectroscopy (MRS) method. The results of the experiment proved that the stress non-uniformity factor δ and the average residual stress σ avg also decreased at a maximum with the combination use of annular groove shape and rivet shape stress release geometries, which is in agreement with the results of FEM analysis. The stress non-uniformity factor δ has a maximum decrease of 49% and the

Work stress, life stress, and smoking among rural–urban migrant workers in China

Directory of Open Access Journals (Sweden)

Cui Xiaobo

2012-11-01

Full Text Available Abstract Background Stimulated by rapid modernization and industrialization, there is massive rural–urban migration in China. The migrants are highly susceptible to smoking and mental health problems. This study examined the association between both perceived work stress and perceived life stress with smoking behavior among this group during the period of migration. Methods Participants (n = 1,595 were identified through stratified, multi-stage, systematic sampling. Smoking status separated non-smokers from daily and occasional smokers, and migration history, work stress, and life stress were also measured. Analyses were conducted using the Chi-square test and multiple logistic regression. Two models were utilized. The first was the full model that comprised sociodemographic and migration-related characteristics, as well as the two stress variables. In addressing potential overlap between life and work stress, the second model eliminated one of the two stress variables as appropriate. Results Overall smoking prevalence was 64.9% (95% CI: 62.4-67.2%. In the regression analysis, under the full model, migrants with high perceived life stress showed a 45% excess likelihood to be current smokers relative to low-stress counterparts (OR: 1.45; 95% CI: 1.05 – 2.06. Applying the second model, which excluded the life stress variable, migrants with high perceived work stress had a 75% excess likelihood to be current smokers relative to opposites (OR: 1.75; 95% CI: 1.26–2.45. Conclusions Rural–urban migrant workers manifested a high prevalence of both life stress and work stress. While both forms of stress showed associations with current smoking, life stress appeared to outweigh the impact of work stress. Our findings could inform the design of tobacco control programs that would target Chinese rural–urban migrant workers as a special population.

Responding to Emotional Stress in Pediatric Hospitals: Results From a National Survey of Chief Nursing Officers.

Science.gov (United States)

Huetsch, Michael; Green, Jeremy

2016-01-01

The aim of this study was to identify leadership awareness of emotional stress and employee support efforts in pediatric hospitals. The current pediatric environment has seen increases in treatment intensity, care duration, and acuity of patients resulting in increased likelihood of being exposed to emotional events. Mail survey was sent to chief nursing officers at 87 pediatric hospitals. A total of 49 responses (56%) were received. Hospitals with less than 250 beds were significantly more likely to rate emotional stress as a large to very large problem, whereas ANCC Magnet® hospitals felt better about support efforts after patient deaths. Most commonly used support offerings focused on staff recovery after a traumatic event as opposed to training for prevention of emotional stress. Emotional stress is a well-recognized issue in pediatric hospitals with comparatively large resource commitment. Further focus on caregiver prevention training and unit leadership recognition of stress may be needed.

Magnitude of shear stress on the san andreas fault: implications of a stress measurement profile at shallow depth.

Science.gov (United States)

Zoback, M D; Roller, J C

1979-10-26

A profile of measurements of shear stress perpendicular to the San Andreas fault near Palmdale, California, shows a marked increase in stress with distance from the fault. The pattern suggests that shear stress on the fault increases slowly with depth and reaches a value on the order of the average stress released during earthquakes. This result has important implications for both long- and shortterm prediction of large earthquakes.

125I-iomazenil binding shows stress- and/or diazepam-induced reductions in mouse brain. Supporting data for 123I-iomazenil SPECT study of anxiety disorders

International Nuclear Information System (INIS)

Takahashi, Makoto; Odano, Ikuo; Fujita, Shozo; Ohkubo, Masaki.

1997-01-01

Effects of repeated swim stress on the binding of 125 I-iomazenil were examined in the brains of diazepam-treated and non-treated mice. The mice were orally administered diazepam or vehicle (0.5% ethylene glycol) and subjected to daily swim stress (at 20degC for 10 min) for seven consecutive days. The distribution and the amount of 125 I-iomazenil binding were analyzed autoradiographically after in vivo and in vitro binding experiments. Repeated swim stress decreased the in vivo binding in the hippocampus (p 125 I-iomazenil binding. These results suggest that we can investigate the pathophysiology of stress and anxiety with 123 I-iomazenil SPECT. Care must be taken concerning the effects of benzodiazepines. (author)

Rock stresses (Grimsel rock laboratory)

International Nuclear Information System (INIS)

Pahl, A.; Heusermann, S.; Braeuer, V.; Gloeggler, W.

1989-01-01

On the research and development project 'Rock Stress Measurements' the BGR has developed and tested several test devices and methods at GTS for use in boreholes at a depth of 200 m and has carried out rock mechanical and engineering geological investigations for the evaluation and interpretation of the stress measurements. The first time a computer for data processing was installed in the borehole together with the BGR-probe. Laboratory tests on hollow cylinders were made to study the stress-deformation behavior. To validate and to interprete the measurement results some test methods were modelled using the finite-element method. The dilatometer-tests yielded high values of Young's modulus, whereas laboratory tests showed lower values with a distinct deformation anisotropy. Stress measurements with the BGR-probe yielded horizontal stresses being higher than the theoretical overburden pressure and vertical stresses which agree well with the theoretical overburden pressure. These results are comparable to the results of the hydraulic fracturing tests, whereas stresses obtained with CSIR-triaxial cells are generally lower. The detailed geological mapping of the borehole indicated relationships between stress and geology. With regard to borehole depth different zones of rock structure joint frequency, joint orientation, and orientation of microfissures as well as stress magnitude, stress direction, and degree of deformation anisotropy could be distinguished. (orig./HP) [de

Acute social stress increases biochemical and self report markers of stress without altering spatial learning in humans.

Science.gov (United States)

Klopp, Christine; Garcia, Carlos; Schulman, Allan H; Ward, Christopher P; Tartar, Jaime L

2012-01-01

Spatial learning is shown to be influenced by acute stress in both human and other animals. However, the intricacies of this relationship are unclear. Based on prior findings we hypothesized that compared to a control condition, a social stress condition would not affect spatial learning performance despite elevated biochemical markers of stress. The present study tested the effects of social stress in human males and females on a subsequent spatial learning task. Social stress induction consisted of evaluative stress (the Trier Social Stress Test, TSST) compared to a placebo social stress. Compared to the placebo condition, the TSST resulted in significantly elevated cortisol and alpha amylase levels at multiple time points following stress induction. In accord, cognitive appraisal measures also showed that participants in the TSST group experienced greater perceived stress compared to the placebo group. However, there were no group differences in performance on a spatial learning task. Our findings suggest that unlike physiological stress, social stress does not result in alterations in spatial learning in humans. It is possible that moderate social evaluative stress in humans works to prevent acute stress-mediated alterations in hippocampal learning processes..

Sleep - nocturnal traffic noise - stress - health: Fundamentals and recent research results. Pt. 2. Recent research results; Schlaf - naechtlicher Verkehrslaerm - Stress - Gesundheit: Grundlagen und aktuelle Forschungsergebnisse. T. 2. Aktuelle Forschungsergebnisse

Energy Technology Data Exchange (ETDEWEB)

Maschke, C. [Technische Univ. Berlin (Germany). Inst. fuer Technische Akustik; Ising, H. [Umweltbundesamt, Berlin (Germany). Inst. fuer Wasser-, Boden- und Lufthygiene; Hecht, K. [Inst. fuer Stressforschung, Berlin (Germany)

1997-03-01

In part 2 of the review, an evaluation is given from the angle of prophylactic medicine, of the results of several experimental and epidemiologic studies on the excretion of stress hormones induced by nocturnal traffic noise. (orig./MG) [Deutsch] In Teil 2 der Uebersichtsarbeit werden Ergebnisse mehrerer experimenteller und epidemiologischer Studien ueber die Stresshormonausscheidung bei naechtlichem Verkehrslaerm vorgestellt und praeventivmedizinisch bewertet. (orig./MG)

The influence of motivation on stress: is it stressful not to fit?

Science.gov (United States)

Schwab, Sebastian; Wolf, Oliver T; Memmert, Daniel

2015-01-01

The present research elaborates on the regulatory fit hypothesis by investigating a biological stress marker in a motivational fit- and non-fit-situation. Recent stress theories lead to the assumption that the participants' stress level in fit-situations remains constant or rather decreases, whereas under non-fit-conditions an increase of the stress activity is observed. We tested this hypothesis by assessment of salivary α-amylase (sAA), a saliva-based stress marker presumed to reflect noradrenergic activity. The results indicated that participants in a fit-situation show a decrease in sAA, whereas participants in a non-fit-situation demonstrate a contrary effect with an increase in sAA. These findings extend the concept of regulatory fit by illustrating that there are differences in sAA activity depending on whether participants are in a fit-situation. The experience of regulatory fit appears to be associated with a reduction of stress.

Show what you know and deal with stress yourself: a qualitative interview study of medical interns' perceptions of stress and gender

NARCIS (Netherlands)

Verdonk, P.; Rantzsch, V.; de Vries, R.; Houkes, I.

2014-01-01

Background: Medical students report high stress levels and in particular, the clinical phase is a demanding one. The field of medicine is still described as having a patriarchal culture which favors aspects like a physicians' perceived certainty and rationalism. Also, the Effort-Recovery Model

The effectiveness of stress inoculation group training (SIT on reducing job stress of employees of RAZAK pharmaceutical company in Tehran

Directory of Open Access Journals (Sweden)

M. Soudani

2011-01-01

Full Text Available Background and aims Despite the fact that work is the major part of human life and the source of satisfying the sense of idealism, innovation and the feeling of consent in the individual, but it is one of the most important factors of creating stress in today's societies. One of the most efficient methods of interfering in stress inoculation group training (SIT. The aim of the present research is the investigation of the efficacy of the stress inoculation group training (SIT on reducing career stress of employees of Razak Co.'s employees.     Methodsthis study is an intermediary study and the research method is experimental of pretest and posttest type with control group. 46 of subjects whose score in career stress test was above the average score were selected as sample, and were replaced in simple random way in two groups of test and control. 8-session test group of 1.5 hours each received team immunity training against stress. Both groups were tested and evaluated three times at the same time (pretest, posttest and follow up.   Resultsafter adjusting the posttest scores based on pretest scores, the results of one-way covariance pretest showed that stress inoculation group training (SIT had a meaningful influence on reduction of career stress on employees. Also the results of multivariable covariance analysis (Mankoa showed that this effect existed in every component of career stress, i.e. exceeding accountability, responsibility of others, very high working pressure, decision making that influences the others, and understanding of self as an individual not quite competent and qualified. In follow up studies after one month, the results showed that stress inoculation group training (SIT has a stable influence on reduction of career stress and it components.   Conclusion on the base of the obtained findings from research and effectiveness from the stress inoculation group training (SIT , it is recommended to apply this therapeutic

Yield stress determination of a physical gel

DEFF Research Database (Denmark)

Hvidt, Søren

2013-01-01

Pluronic F127 solutions form gels in water with high elastic moduli. Pluronic gels can, however, only withstand small deformations and stresses. Different steady shear and oscillatory methods traditionally used to determine yield stress values are compared. The results show that the yield stresses...... values of these gels depend on test type and measurement time, and no absolute yield stress value can be determined for these physical gels....

Pre-test analysis results of a PWR steel lined pre-stressed concrete containment model

International Nuclear Information System (INIS)

Basha, S.M.; Ghosh, Barnali; Patnaik, R.; Ramanujam, S.; Singh, R.K.; Kushwaha, H.S.; Venkat Raj, V.

2000-02-01

Pre-stressed concrete nuclear containment serves as the ultimate barrier against the release of radioactivity to the environment. This ultimate barrier must be checked for its ultimate load carrying capacity. BARC participated in a Round Robin analysis activity which is co-sponsored by Sandia National Laboratory, USA and Nuclear Power Engineering Corporation Japan for the pre-test prediction of a 1:4 size Pre-stressed Concrete Containment Vessel. In house finite element code ULCA was used to make the test predictions of displacements and strains at the standard output locations. The present report focuses on the important landmarks of the pre-test results, in sequential terms of first crack appearance, loss of pre-stress, first through thickness crack, rebar and liner yielding and finally liner tearing at the ultimate load. Global and local failure modes of the containment have been obtained from the analysis. Finally sensitivity of the numerical results with respect to different types of liners and different constitutive models in terms of bond strength between concrete and steel and tension-stiffening parameters are examined. The report highlights the important features which could be observed during the test and guidelines are given for improving the prediction in the post test computation after the test data is available. (author)

Acute Lung Injury Results from Innate Sensing of Viruses by an ER Stress Pathway

Directory of Open Access Journals (Sweden)

Eike R. Hrincius

2015-06-01

Full Text Available Incursions of new pathogenic viruses into humans from animal reservoirs are occurring with alarming frequency. The molecular underpinnings of immune recognition, host responses, and pathogenesis in this setting are poorly understood. We studied pandemic influenza viruses to determine the mechanism by which increasing glycosylation during evolution of surface proteins facilitates diminished pathogenicity in adapted viruses. ER stress during infection with poorly glycosylated pandemic strains activated the unfolded protein response, leading to inflammation, acute lung injury, and mortality. Seasonal strains or viruses engineered to mimic adapted viruses displaying excess glycans on the hemagglutinin did not cause ER stress, allowing preservation of the lungs and survival. We propose that ER stress resulting from recognition of non-adapted viruses is utilized to discriminate “non-self” at the level of protein processing and to activate immune responses, with unintended consequences on pathogenesis. Understanding this mechanism should improve strategies for treating acute lung injury from zoonotic viral infections.

Maternal obesity and malnourishment exacerbate perinatal oxidative stress resulting in diabetogenic programming in F1 offspring.

Science.gov (United States)

Saad, M I; Abdelkhalek, T M; Haiba, M M; Saleh, M M; Hanafi, M Y; Tawfik, S H; Kamel, M A

2016-06-01

The effect of in-utero environment on fetal health and survival is long-lasting, and this is known as the fetal origin hypothesis. The oxidative stress state during gestation could play a pivotal role in fetal programming and development of diseases such as diabetes. In this study, we investigated the effect of intra-uterine obesity and malnutrition on oxidative stress markers in pancreatic and peripheral tissues of F1 offspring both prenatally and postnatally. Furthermore, the effect of postnatal diet on oxidative stress profile was evaluated. The results indicated that intra-uterine obesity and malnourishment significantly increased oxidative stress in F1 offspring. Moreover, the programming effect of obesity was more pronounced and protracted than malnutrition. The obesity-induced programming of offspring tissues was independent of high-caloric environment that the offspring endured; however, high-caloric diet potentiated its effect. In addition, pancreas and liver were the most affected tissues by fetal reprogramming both prenatally and postnatally. In conclusion, maternal obesity and malnutrition-induced oxidative stress could predispose offspring to insulin resistance and diabetes.

Self-affirmation improves problem-solving under stress.

Science.gov (United States)

Creswell, J David; Dutcher, Janine M; Klein, William M P; Harris, Peter R; Levine, John M

2013-01-01

High levels of acute and chronic stress are known to impair problem-solving and creativity on a broad range of tasks. Despite this evidence, we know little about protective factors for mitigating the deleterious effects of stress on problem-solving. Building on previous research showing that self-affirmation can buffer stress, we tested whether an experimental manipulation of self-affirmation improves problem-solving performance in chronically stressed participants. Eighty undergraduates indicated their perceived chronic stress over the previous month and were randomly assigned to either a self-affirmation or control condition. They then completed 30 difficult remote associate problem-solving items under time pressure in front of an evaluator. Results showed that self-affirmation improved problem-solving performance in underperforming chronically stressed individuals. This research suggests a novel means for boosting problem-solving under stress and may have important implications for understanding how self-affirmation boosts academic achievement in school settings.

Effect of stress management interventions on job stress among nurses working in critical care units.

Science.gov (United States)

Light Irin, C; Bincy, R

2012-01-01

Stress in nurses affects their health and increases absenteeism, attrition rate, injury claims, infection rates and errors in treating patients. This in turn significantly increases the cost of employment in healthcare units. Proper management of stress ensures greater efficiency at work place and improved wellbeing of the employee. Therefore, a pre-experimental study was conducted among 30 Critical Care Unit nurses working inMedical College Hospital, Thiruvananthapuram, (Kerala) to assess the effect of stress management interventions such as Job Stress Awareness, Assertiveness Training, Time Management, andProgressive Muscle Relaxation on job stress. The results showed that caring for patients, general job requirements and workload were the major sources of stress for the nurses. The level of severe stress was reduced from 60 percent to 20 percent during post-test. The Stress Management Interventions were statistically effective in reducing the stress of nurses at p<0.001 level.

Different stress modalities result in distinct steroid hormone responses by male rats

Directory of Open Access Journals (Sweden)

M.L. Andersen

2004-06-01

Full Text Available Since both paradoxical sleep deprivation (PSD and stress alter male reproductive function, the purpose of the present study was to examine the influence of PSD and other stressors (restraint, electrical footshock, cold and forced swimming, N = 10 per group on steroid hormones in adult Wistar male rats. Rats were submitted to chronic stress for four days. The stressors (footshock, cold and forced swimming were applied twice a day, for periods of 1 h at 9:00 and 16:00 h. Restrained animals were maintained in plastic cylinders for 22 h/day whereas PSD was continuous. Hormone determination was measured by chemiluminescent enzyme immunoassay (testosterone, competitive immunoassay (progesterone and by radioimmunoassay (corticosterone, estradiol, estrone. The findings indicate that PSD (13.7 ng/dl, footshock (31.7 ng/dl and cold (35.2 ng/dl led to lower testosterone levels compared to the swimming (370.4 ng/dl and control (371.4 ng/dl groups. However, progesterone levels were elevated in the footshock (4.5 ng/ml and PSD (5.4 ng/ml groups compared to control (1.6 ng/ml, swimming (1.1 ng/ml, cold (2.3 ng/ml, and restrained (1.2 ng/ml animals. Estrone and estradiol levels were reduced in the PSD, footshock and restraint groups compared to the control, swimming and cold groups. A significant increase in corticosterone levels was found only in the PSD (299.8 ng/ml and footshock (169.6 ng/ml groups. These changes may be thought to be the full steroidal response to stress of significant intensity. Thus, the data suggest that different stress modalities result in distinct steroid hormone responses, with PSD and footshock being the most similar.

Extraversion and cardiovascular responses to recurrent social stress: Effect of stress intensity.

Science.gov (United States)

Lü, Wei; Xing, Wanying; Hughes, Brian M; Wang, Zhenhong

2017-10-28

The present study sought to establish whether the effects of extraversion on cardiovascular responses to recurrent social stress are contingent on stress intensity. A 2×5×1 mixed-factorial experiment was conducted, with social stress intensity as a between-subject variable, study phase as a within-subject variable, extraversion as a continuous independent variable, and cardiovascular parameter (HR, SBP, DBP, or RSA) as a dependent variable. Extraversion (NEO-FFI), subjective stress, and physiological stress were measured in 166 undergraduate students randomly assigned to undergo moderate (n=82) or high-intensity (n=84) social stress (a public speaking task with different levels of social evaluation). All participants underwent continuous physiological monitoring while facing two consecutive stress exposures distributed across five laboratory phases: baseline, stress exposure 1, post-stress 1, stress exposure 2, post-stress 2. Results indicated that under moderate-intensity social stress, participants higher on extraversion exhibited lesser HR reactivity to stress than participants lower on extraversion, while under high-intensity social stress, they exhibited greater HR, SBP, DBP and RSA reactivity. Under both moderate- and high-intensity social stress, participants higher on extraversion exhibited pronounced SBP and DBP response adaptation to repeated stress, and showed either better degree of HR recovery or greater amount of SBP and DBP recovery after stress. These findings suggest that individuals higher on extraversion exhibit physiological flexibility to cope with social challenges and benefit from adaptive cardiovascular responses. Copyright © 2017 Elsevier B.V. All rights reserved.

The interplay of multiple feedback loops with post-translational kinetics results in bistability of mycobacterial stress response

International Nuclear Information System (INIS)

Tiwari, Abhinav; Igoshin, Oleg A; Balázsi, Gábor; Gennaro, Maria Laura

2010-01-01

Bacterial persistence is the phenomenon in which a genetically identical fraction of a bacterial population can survive exposure to stress by reduction or cessation of growth. Persistence in mycobacteria has been recently linked to a stress-response network, consisting of the MprA/MprB two-component system and alternative sigma factor σ E . This network contains multiple positive transcriptional feedback loops which may give rise to bistability, making it a good candidate for controlling the mycobacterial persistence switch. To analyze the possibility of bistability, we develop a method that involves decoupling of the network into transcriptional and post-translational interaction modules. As a result we reduce the dimensionality of the dynamical system and independently analyze input–output relations in the two modules to formulate a necessary condition for bistability in terms of their logarithmic gains. We show that neither the positive autoregulation in the MprA/MprB network nor the σ E -mediated transcriptional feedback is sufficient to induce bistability in a biochemically realistic parameter range. Nonetheless, inclusion of the post-translational regulation of σ E by RseA increases the effective cooperativity of the system, resulting in bistability that is robust to parameter variation. We predict that overexpression or deletion of RseA, the key element controlling the ultrasensitive response, can eliminate bistability

Heat indicators of oxidative stress, inflammation and metal transport show dependence of cadmium pollution history in the liver of female zebrafish.

Science.gov (United States)

Zhu, Qing-Ling; Guo, Sai-Nan; Yuan, Shuang-Shuang; Lv, Zhen-Ming; Zheng, Jia-Lang; Xia, Hu

2017-10-01

Environmental stressors such as high temperature and metal exposure may occur sequentially, simultaneously, previously in aquatic ecosystems. However, information about whether responses to high temperature depend on Cd exposure history is still unknown in fish. Zebrafish were exposed to 0 (group 1), 2.5 (group 2) and 5μg/L (group 3) cadmium (Cd) for 10 weeks, and then each group was subjected to Cd-free water maintained at 26°C and 32°C for 7days respectively. 26 indicators were used to compare differences between 26°C and 32°C in the liver of female zebrafish, including 5 biochemical indicators (activity of Cu/Zn-SOD, CAT and iNOS; LPO; MT protein), 8 molecular indicators of oxidative stress (mRNA levels of Nrf2, Cu/Zn-SOD, CAT, HSF1, HSF2, HSP70, MTF-1 and MT), 5 molecular indicators of inflammation (mRNA levels of IL-6, IL-1β, TNF-α, iNOS and NF-κB), 8 molecular indicators of metal transport (mRNA levels of, ZnT1, ZnT5, ZIP8, ZIP10, ATP7A, ATP7B and CTR1). All biochemical indicators were unchanged in group 1 and changed in group 2 and 3. Contrarily, differences were observed in almost all of molecular indicators of inflammation and metal transport in group 1, about half in group 2, and few in group 3. We also found that all molecular indicators of oxidative stress in group 2 and fewer in group 1 and 3 were significantly affected by heat. Our data indicated that heat indicators of oxidative stress, inflammation and metal transport showed dependence of previous cadmium exposure in the liver of zebrafish, emphasizing metal pollution history should be carefully considered when evaluating heat stress in fish. Copyright © 2017. Published by Elsevier B.V.

Test Results of a Nb3Sn Wind/React ''Stress-Managed'' Block Dipole

International Nuclear Information System (INIS)

McInturff, A.; Bish, P.; Blackburn, R.; Diaczenko, N.; Elliott, T.; Hafalia Jr., R.; Henchel, W.; Jaisle, A.; Lau, W.; Lietzke, A.; McIntyre, P.; Noyes, P.; Nyman, M.; Sattarov, A.; Sattarov, A.

2006-01-01

A second phase of a highfield dipole technology development has been tested. A Nb3Sn block-coil model dipole was fabricated, using magnetic mirror geometry and wind/react coil technology. The primary objective of this phase was to make a first experimental test of the stress-management strategy pioneered at Texas A and M. In this strategy a high-strength support matrix is integrated with the windings to intercept Lorentz stress from the inner winding so that it does not accumulate in the outer winding. The magnet attained a field that was consistent with short sample limit on the first quench; there was no training. The decoupling of Lorentz stress between inner and outer windings was validated. In ramp rate studies the magnet exhibited a remarkable robustness in rapid ramping operation. It reached 85 percent of short sample(ss) current even while ramping 2-3 T/s. This robustness is attributed to the orientation of the Rutherford cables parallel to the field in the windings, instead of the transverse orientation that characterizes common dipole designs. Test results are presented and the next development phase plans are discussed

Shifts of heat availability and stressful temperatures in Russian Federation result in gains and losses of wheat thermal suitability

Science.gov (United States)

Di Paola, Arianna; Caporaso, Luca; Santini, Monia; Di Paola, Francesco; Vasenev, Ivan; Valentini, Riccardo

2017-04-01

Climate changes are likely to shift the suitability of lands devoted to cropping systems. We explored the past-to-future thermal suitability of Russian Federation for wheat (Triticum aestivum) culture through an ensemble of bias corrected CMIP5-GCMs outputs considering two representative concentration pathways (RCP 4.5 and 8.5). Thermal suitability assesses where wheat heat requirement, counted from suggested sowing dates, is satisfied without the occurrence of stressful hot and frost temperatures. Thermal requirement was estimated by means of phenological observations on soft wheat involving different wheat cultivar collected in different regions of Russian Federation, Azerbaidhan, Kazakhstan and Tadzhikistan, whilst stressful temperatures were taken from a literature survey. Results showed projected geographical shift of heat resource toward the north-eastern regions, currently mainly covered by forests and croplands, but also an increase of very hot temperatures in the most productive areas of the southern regions. Gains and losses were then quantified and discussed from both agronomical and climatic perspective.

Effectiveness of a Dental Students Stress Management Program

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Abdullah M. Alzahem

2015-12-01

Full Text Available The dental education stress effects and sources were explored thoroughly in the literature, but the effectiveness of stress management programs received less attention. This study introduced a new stress management program, named Dental Education Stress Management (DESM program. It showed its effectiveness in a quasi-experimental pretest-posttest-follow-up-control group design. The new program was based on the principle of psychoeducation and consisted of three 90-min sessions, to teach dental students how to better deal with their stress symptoms and to reduce their general stress level. Two instruments were used to assess the level of stress of the dental students, namely the Dental Environment Stress questionnaire (DES, and the Psychological Stress Measure (PSM-9. Results show that the DESM program has the desired effect of decreasing the stress levels of its participants, and these effects lasted for at least two weeks. Because of several methodological limitations of the study more research is needed to draw more generalizable conclusions.

Stress transmission in soil

DEFF Research Database (Denmark)

Lamandé, Mathieu; Schjønning, Per

We urgently need increased quantitative knowledge on stress transmission in real soils loaded with agricultural machinery. 3D measurements of vertical stresses under tracked wheels were performed in situ in a Stagnic Luvisol (clay content 20 %) continuously cropped with small grain cereals......). Seven load cells were inserted horizontally from a pit with minimal disturbance of soil in each of three depths (0.3, 0.6 and 0.9 m), covering the width of the wheeled area. The position of the wheel relative to the transducers was recorded using a laser sensor. Finally, the vertical stresses near...... the soil-tyre interface were measured in separate tests by 17 stress transducers across the width of the tyres. The results showed that the inflation pressure controlled the level of maximum stresses at 0.3 m depth, while the wheel load was correlated to the measured stresses at 0.9 m depth. This supports...

Photoelastic stress analysis in mitred bend under internal pressure

International Nuclear Information System (INIS)

Sawa, Yoshiaki

1987-01-01

The stress analysis and stress relaxation in mitred bend subjected to internal pressure have been studied by means of the photoelastic stress freezing method. The experimental results show that stress concentration occurs in the wedge tip of the intersectional plane and it is considerably influenced by the bent angle. Then, the stress relaxation was obtained by planing the wedge tip. (author)

Acute stress does not affect the impairing effect of chronic stress on memory retrieval

Science.gov (United States)

Ozbaki, Jamile; Goudarzi, Iran; Salmani, Mahmoud Elahdadi; Rashidy-Pour, Ali

2016-01-01

Objective(s): Due to the prevalence and pervasiveness of stress in modern life and exposure to both chronic and acute stresses, it is not clear whether prior exposure to chronic stress can influence the impairing effects of acute stress on memory retrieval. This issue was tested in this study. Materials and Methods: Adult male Wistar rats were randomly assigned to the following groups: control, acute, chronic, and chronic + acute stress groups. The rats were trained with six trials per day for 6 consecutive days in the water maze. Following training, the rats were either kept in control conditions or exposed to chronic stress in a restrainer 6 hr/day for 21 days. On day 22, a probe test was done to measure memory retention. Time spent in target and opposite areas, platform location latency, and proximity were used as indices of memory retention. To induce acute stress, 30 min before the probe test, animals received a mild footshock. Results: Stressed animals spent significantly less time in the target quadrant and more time in the opposite quadrant than control animals. Moreover, the stressed animals showed significantly increased platform location latency and proximity as compared with control animals. No significant differences were found in these measures among stress exposure groups. Finally, both chronic and acute stress significantly increased corticosterone levels. Conclusion: Our results indicate that both chronic and acute stress impair memory retrieval similarly. Additionally, the impairing effects of chronic stress on memory retrieval were not influenced by acute stress. PMID:27635201

Transcriptome analysis shows activation of the arginine deiminase pathway in Lactococcus lactis as a response to ethanol stress.

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Díez, Lorena; Solopova, Ana; Fernández-Pérez, Rocío; González, Miriam; Tenorio, Carmen; Kuipers, Oscar P; Ruiz-Larrea, Fernanda

2017-09-18

This paper describes the molecular response of Lactococcus lactis NZ9700 to ethanol. This strain is a well-known nisin producer and a lactic acid bacteria (LAB) model strain. Global transcriptome profiling using DNA microarrays demonstrated a bacterial adaptive response to the presence of 2% ethanol in the culture broth and differential expression of 67 genes. The highest up-regulation was detected for those genes involved in arginine degradation through the arginine deiminase (ADI) pathway (20-40 fold up-regulation). The metabolic responses to ethanol of wild type L. lactis strains were studied and compared to those of regulator-deletion mutants MG∆argR and MG∆ahrC. The results showed that in the presence of 2% ethanol those strains with an active ADI pathway reached higher growth rates when arginine was available in the culture broth than in absence of arginine. In a chemically defined medium strains with an active ADI pathway consumed arginine and produced ornithine in the presence of 2% ethanol, hence corroborating that arginine catabolism is involved in the bacterial response to ethanol. This is the first study of the L. lactis response to ethanol stress to demonstrate the relevance of arginine catabolism for bacterial adaptation and survival in an ethanol containing medium. Copyright © 2017 Elsevier B.V. All rights reserved.

A study on factors of dissatisfaction and stress of the blacksmiths resulting from the organizational culture in the surgical instrument industry of India

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Tirthankar Ghosh

2011-01-01

Full Text Available Background: It is important to understand what motivates workers and the extent to which the organization and other contextual variables satisfy them. The aim of the study was to determine factors of dissatisfaction resulting from the organizational culture among the blacksmiths involved in the surgical instrument industry. Materials and Methods: Fifty male surgical blacksmiths each of the skilled and unskilled groups of the forging section were selected. Organizational Role Stress Scale was used to measure the individuals′ role stress and several forms of conflict within an organization. Also, the organizational culture and personal involvement in an organization was measured among the surgical blacksmiths. Results: The mean score for total role stress for Skilled was 71.7 and for unskilled was 77.2. The most frequent type of organizational culture was reported to be hierarchy, both by skilled and unskilled surgical blacksmiths, followed by market and clan culture. Conclusion: This study shows that the skilled surgical blacksmiths have lower level of stress and conflicts in comparison with unskilled surgical blacksmiths. Both skilled and unskilled surgical blacksmiths estimated their level of personal involvement as low and indicated insufficient involvement in work teams. The satisfaction of the employees with their status and role in the organizational culture was also poor for both skilled and unskilled surgical blacksmiths.

Gender differences in the experience of Postraumatic Stress

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Nevzat Shemsedini

2016-03-01

Full Text Available The aim of this research is to understand whether there are gender differences in the symptoms of stress post-traumatic stress disorder. Many researches that have been made in this area have reached the conclusion that there are gender differences in the symptoms of stress posttraumatic stress disorder. To investigate this issue is to select a sample of 100 respondents, the selection of whom is done at random, with people who we have met in the street the library, the faculties of other public sites. The research was of the type quantitative – where the data are collected through the application of questionnaires. The results from this survey show that there are gender differences in the symptoms of stress post-traumatic stress disorder. So, women survive with the many symptoms of stress post-traumatic stress disorder than men. The results are processed with the Analysis of data ,with the program SPSS.- krostabulim (crosstabulation Gender with questions. The aim of this research is to understand whether there are gender differences in the symptoms of stress post-traumatic stress disorder. Many researches that have been made in this area have reached the conclusion that there are gender differences in the symptoms of stress post-traumatic stress disorder. To investigate this issue is to select a sample of 100 respondents, the selection of whom is done at random, with people who we have met in the street the library, the faculties of other public sites. The research was of the type quantitative – where the data are collected through the application of questionnaires. The results from this survey show that there are gender differences in the symptoms of stress post-traumatic stress disorder. So, women perjetojnë with the many symptoms of stress post-traumatic stress disorder than men. The results are processed with the Analysis of data ,with the program SPSS.- krostabulim (crosstabulation Gender with questions.

Effects of stress on heart rate complexity--a comparison between short-term and chronic stress.

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Schubert, C; Lambertz, M; Nelesen, R A; Bardwell, W; Choi, J-B; Dimsdale, J E

2009-03-01

This study examined chronic and short-term stress effects on heart rate variability (HRV), comparing time, frequency and phase domain (complexity) measures in 50 healthy adults. The hassles frequency subscale of the combined hassles and uplifts scale (CHUS) was used to measure chronic stress. Short-term stressor reactivity was assessed with a speech task. HRV measures were determined via surface electrocardiogram (ECG). Because respiration rate decreased during the speech task (pshort-term stress decreased HR D2 (calculated via the pointwise correlation dimension PD2) (pshort-term stress. Partial correlation adjusting for respiration rate showed that HR D2 was associated with chronic stress (r=-.35, p=.019). Differential effects of chronic and short-term stress were observed on several HRV measures. HR D2 decreased under both stress conditions reflecting lowered functionality of the cardiac pacemaker. The results confirm the importance of complexity metrics in modern stress research on HRV.

Self-affirmation improves problem-solving under stress.

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J David Creswell

Full Text Available High levels of acute and chronic stress are known to impair problem-solving and creativity on a broad range of tasks. Despite this evidence, we know little about protective factors for mitigating the deleterious effects of stress on problem-solving. Building on previous research showing that self-affirmation can buffer stress, we tested whether an experimental manipulation of self-affirmation improves problem-solving performance in chronically stressed participants. Eighty undergraduates indicated their perceived chronic stress over the previous month and were randomly assigned to either a self-affirmation or control condition. They then completed 30 difficult remote associate problem-solving items under time pressure in front of an evaluator. Results showed that self-affirmation improved problem-solving performance in underperforming chronically stressed individuals. This research suggests a novel means for boosting problem-solving under stress and may have important implications for understanding how self-affirmation boosts academic achievement in school settings.

Structure-dependent behavior of stress-induced voiding in Cu interconnects

International Nuclear Information System (INIS)

Wu Zhenyu; Yang Yintang; Chai Changchun; Li Yuejin; Wang Jiayou; Li Bin; Liu Jing

2010-01-01

Stress modeling and cross-section failure analysis by focused-ion-beam have been used to investigate stress-induced voiding phenomena in Cu interconnects. The voiding mechanism and the effect of the interconnect structure on the stress migration have been studied. The results show that the most concentrated tensile stress appears and voids form at corners of vias on top surfaces of Cu M1 lines. A simple model of stress induced voiding in which vacancies arise due to the increase of the chemical potential under tensile stress and diffuse under the force of stress gradient along the main diffusing path indicates that stress gradient rather than stress itself determines the voiding rate. Cu interconnects with larger vias show less resistance to stress-induced voiding due to larger stress gradient at corners of vias.

Acute stress affects risk taking but not ambiguity aversion.

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Buckert, Magdalena; Schwieren, Christiane; Kudielka, Brigitte M; Fiebach, Christian J

2014-01-01

Economic decisions are often made in stressful situations (e.g., at the trading floor), but the effects of stress on economic decision making have not been systematically investigated so far. The present study examines how acute stress influences economic decision making under uncertainty (risk and ambiguity) using financially incentivized lotteries. We varied the domain of decision making as well as the expected value of the risky prospect. Importantly, no feedback was provided to investigate risk taking and ambiguity aversion independent from learning processes. In a sample of 75 healthy young participants, 55 of whom underwent a stress induction protocol (Trier Social Stress Test for Groups), we observed more risk seeking for gains. This effect was restricted to a subgroup of participants that showed a robust cortisol response to acute stress (n = 26). Gambling under ambiguity, in contrast to gambling under risk, was not influenced by the cortisol response to stress. These results show that acute psychosocial stress affects economic decision making under risk, independent of learning processes. Our results further point to the importance of cortisol as a mediator of this effect.

Character strengths, social anxiety, and physiological stress reactivity

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Tingting Li

2017-05-01

Full Text Available In this paper, the effects of character strengths on the physiological reactivity to social anxiety induced by the Trier Social Stress Task were reported. On the basis of their scores in the Chinese Virtues Questionnaire, 30 college students were assigned to either high- (n = 15 or low-character-strength (n = 15 groups. Their psychological stress and physiological data across three laboratory stages (namely, baseline, stress exposure, and post-stress were collected. Results indicated that individuals with high character strengths exhibited rapid cardiovascular recovery from baseline to post-stress even if high- and low-character-strength groups showed similar patterns of cardiovascular arousal in response to the stress at baseline and stress exposure. These results prove that character strengths are stress-defense factors that allow for psychological and physiological adaptation to stress.

Social factors modulate restraint stress induced hyperthermia in mice.

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Watanabe, Shigeru

2015-10-22

Stress-induced hyperthermia (SIH) was examined in three different social conditions in mice by thermographic measurement of the body surface temperature. Placing animals in cylindrical holders induced restraint stress. I examined the effect of the social factors in SIH using the thermograph (body surface temperature). Mice restrained in the holders alone showed SIH. Mice restrained in the holders at the same time as other similarly restrained cage mates (social equality condition) showed less hyperthermia. Interestingly, restrained mice with free moving cage mates (social inequality condition) showed the highest hyperthermia. These results are consistent with a previous experiment measuring the memory-enhancing effects of stress and the stress-induced elevation of corticosterone, and suggest that social inequality enhances stress. Copyright © 2015 Elsevier B.V. All rights reserved.

Coatings influencing thermal stress in photonic crystal fiber laser

Science.gov (United States)

Pang, Dongqing; Li, Yan; Li, Yao; Hu, Minglie

2018-06-01

We studied how coating materials influence the thermal stress in the fiber core for three holding methods by simulating the temperature distribution and the thermal stress distribution in the photonic-crystal fiber laser. The results show that coating materials strongly influence both the thermal stress in the fiber core and the stress differences caused by holding methods. On the basis of the results, a two-coating PCF was designed. This design reduces the stress differences caused by variant holding conditions to zero, then the stability of laser operations can be improved.

Thermal stress and seismogenesis

International Nuclear Information System (INIS)

Zhou Huilan; Wei Dongping

1989-05-01

In this paper, the Fourier stress method was applied to deal with the problem of plane thermal stress, and a computing formula was given. As an example, we set up a variate temperature field to describe the uplifted upper mantle in Bozhong area of China, and the computing results shows that the maximum value of thermal plane shear stress is up to nearly 7x10 7 P α in two regions of this area. Since the Bohai earthquake (18 July, 1969, M s = 7.4) occurred at the edge of one of them and Tangshan earthquake (28 July, 1976, M s = 7.8) within another, their occurrences can be related reasonably to the thermal stress. (author). 15 refs, 7 figs

Stress levels in parents of children with and without attention deficit hyperactivity disorder during the back-to-school period: results of an international survey in Italy.

Science.gov (United States)

Loprieno, Urania; Gagliano, Antonella

2016-10-01

The back-to-school stress survey was an international, non-clinical opinion survey, which aimed to compare stress levels in parents of children with/without attention deficit hyperactivity disorder (ADHD) during the back-to-school period. Here, we present results relating to the Italian sample, comparing them with European data. The questionnaire was built using a modified Holmes and Rahe stress scale. Parents of children with/without ADHD evaluated potentially stress-causing situations on a scale from 1 (low stress) to 10 (high stress). In Italy, 107 parents of children with ADHD (mean age ± SD 40.3±7.3 years) and 105 parents of children without ADHD (mean age 42.2±6.6 years) participated in the survey. The mean age of children with ADHD was 10.3±3.1 years; 77.6% were male, 72.9% had been diagnosed with at least one comorbid condition - in particular conduct disorder (24.3%), learning disorders/dyslexia (23.4%) and language/communication disorder (19.6%) - and 32.7% were receiving ADHD medication. Parents of children with ADHD showed significantly higher stress levels (p≤0.005) compared with the non-ADHD group in all areas analyzed that were related to the return to school. Significant differences between groups (Pchildren with ADHD suffer significantly higher stress levels compared with parents of children without ADHD. Considering parental stress is important for the management of children with ADHD, as stress can affect the control of behavioral symptoms of children.

Do uniform tangential interfacial stresses enhance adhesion?

Science.gov (United States)

Menga, Nicola; Carbone, Giuseppe; Dini, Daniele

2018-03-01

We present theoretical arguments, based on linear elasticity and thermodynamics, to show that interfacial tangential stresses in sliding adhesive soft contacts may lead to a significant increase of the effective energy of adhesion. A sizable expansion of the contact area is predicted in conditions corresponding to such scenario. These results are easily explained and are valid under the assumptions that: (i) sliding at the interface does not lead to any loss of adhesive interaction and (ii) spatial fluctuations of frictional stresses can be considered negligible. Our results are seemingly supported by existing experiments, and show that frictional stresses may lead to an increase of the effective energy of adhesion depending on which conditions are established at the interface of contacting bodies in the presence of adhesive forces.

Coregulation of endoplasmic reticulum stress and oxidative stress in neuropathic pain and disinhibition of the spinal nociceptive circuitry.

Science.gov (United States)

Ge, Yanhu; Jiao, Yingfu; Li, Peiying; Xiang, Zhenghua; Li, Zhi; Wang, Long; Li, Wenqian; Gao, Hao; Shao, Jiayun; Wen, Daxiang; Yu, Weifeng

2018-05-01

The accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER) lumen leads to ER stress, which is related to cellular reactive oxygen species production. Neuropathic pain may result from spinal dorsal horn (SDH) ER stress. In this study, we examined the cause-effect relationship between ER stress and neuropathic pain using the spinal nerve ligation (SNL) rat model. We showed that ER stress was mutually promotive with oxidative stress during the process. We also tested the hypothesis that spinal sensitization arose from reduced activities of GABA-ergic interneurons and that spinal sensitization was mediated by SDH ER stress. Other important findings in this study including the following: (1) nociceptive behavior was alleviated in SNL rat as long as tauroursodeoxycholic acid injections were repeated to inhibit ER stress; (2) inducing SDH ER stress in healthy rat resulted in mechanical hyperalgesia; (3) blocking protein disulfide isomerase pharmacologically reduced ER stress and nociceptive behavior in SNL rat; (4) cells in the dorsal horn with elevated ER stress were mainly neurons; and (5) whole-cell recordings made in slide preparations revealed significant inhibition of GABA-ergic interneuron activity in the dorsal horn with ER stress vs in the healthy dorsal horn. Taken together, results of the current study demonstrate that coregulation of ER stress and oxidative stress played an important role in neuropathic pain process. Inhibiting SDH ER stress could be a potential novel strategy to manage neuropathic pain.

Stress measurements in the Naesliden Mine

Energy Technology Data Exchange (ETDEWEB)

Leijon, B. [Univ. of Luleaa, Sweden; Carlsson, H.; Myrvang, A.

1980-05-15

Determinations of virgin stresses were performed at an early stage of the Naesliden Project in order to obtain input data for the finite element models of the mine. The Leeman three-dimensional overcoring technique was used at five locations on levels ranging from 210 m to 460 m below surface. Stress data were obtained at four of these locations. The results show an excess of horizontal stresses whilst the vertical stress is in accordance with the gravitational load from the overburden. The major and intermediate principal stresses are sub-horizontal and directed respectively perpendicular and parallel to the schisotsity of the wall rock and the strike of the tabular ore body. The minor principal stress is directed almost vertically. Stresses were also measured close to a stope on 300 m level in the mine. Biaxial and triaxial overcoring measurements were made at eighteen points between 0.25 m and 7.2 m above the roof of the stope. The stresses were found to have magnitudes of about 70 MPa close to the roof and to decrease rapidly with the distance from the roof. Stress measurements were made in connection with slot blastings in the foot wall, the latter measure being made in an attempt to de-stress the roof of stope 3. Two methods were used for stress monitorings, both showing that expected stress changes did not take place. Long-term stress guages have been installed in the ore body in order to monitor expected re-distributions of stresses due to mining. So far, the recorded stress changes are below 5 MPa.

Establishment of a finite element model of a neonate's skull to evaluate the stress pattern distribution resulting during nasoalveolar molding therapy of cleft lip and palate patients.

Science.gov (United States)

Bauer, Franz X; Heinrich, Veronika; Grill, Florian D; Wölfle, Felix; Hedderich, Dennis M; Rau, Andrea; Wolff, Klaus-Dietrich; Ritschl, Lucas M; Loeffelbein, Denys J

2018-04-01

Nasoalveolar Molding (NAM) is associated with ambivalent acceptance regarding effectiveness and unknown long-term results. Our purpose was to analyze the stress distribution patterns within the viscero- and neurocranium of neonates during the first phase of NAM therapy. A finite element (FE) model of a healthy four-week-old neonate was generated, derived from a computed tomography scan allowing the implementation of a bone-density-dependent material model. The influence of dental germs with variable material properties, the cleft width and area of expected force application were analyzed in a worst-case scenario. The resulting stress distribution patterns for each situation were analyzed using the software Ansys APDL. The established FE model was verified with a convergence analysis. Overall, stress patterns at the age of four weeks showed von Mises stress values below 60.000 Pa in the viscero- and neurocranium. The influences of the allocation of material properties for the dental germs, the area of force application, and the cleft width were negligible. A workflow to simulate the stress distribution and deformation in neonates attributable to various areas of force application has been established. Further analyses of the skulls of younger and older neonates are needed to describe the stress distribution patterns during NAM therapy. Copyright © 2018 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Testing Delays Resulting in Increased Identification Accuracy in Line-Ups and Show-Ups.

Science.gov (United States)

Dekle, Dawn J.

1997-01-01

Investigated time delays (immediate, two-three days, one week) between viewing a staged theft and attempting an eyewitness identification. Compared lineups to one-person showups in a laboratory analogue involving 412 subjects. Results show that across all time delays, participants maintained a higher identification accuracy with the showup…

Acute Cold / Restraint Stress in Castrated Rats

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Farideh Zafari Zangeneh

2008-09-01

Full Text Available Objective: The present study aimed to determine whether castration altered osmotically stimulated vasopressin (VP release and urinary volume and what is the role of endocrine-stress axis in this process.Materials and methods: Totally 108 mice were studied in two main groups of castrated (n=78 and control (n=30. Each group was extracted by acute cold stress (4◦C for 2h/day, restraint stress (by syringes 60cc 2h/day and cold/restraint stress. The castrated group was treated in sub groups of testosterone, control (sesame oil as vehicle of testosterone. Propranolol as blocker of sympathetic nervous system was given to both groups of castrated mice and main control.Results: Our results showed that, there is interactions between testosterone and sympathetic nervous system on vasopressin, because urine volume was decreased only in testoctomized mice with cold/restraint and cold stress (P<0.001; propranolol as the antagonist of sympathetic nervous system could block and increase urine volume in castrated mice. This increased volume of urine was due to acute cold stress, not restraint stress (p<0.001. The role of testosterone, noradrenalin (NA and Vasopressin (VP in the acute cold stress is confirmed, because testosterone could return the effect of decreased urine volume in control group (P<0.001. Conclusion: Considering the effect of cold/restraint stress on urinary volume in castrated mice shows that there is interaction between sex hormone (testosterone, vasopressin and adrenergic systems.

Human neuroblastoma SH-SY5Y cells show increased resistance to hyperthermic stress after differentiation, associated with elevated levels of Hsp72.

Science.gov (United States)

Cheng, Lesley; Smith, Danielle J; Anderson, Robin L; Nagley, Phillip

2011-01-01

Terminally differentiated neurones in the central nervous system need to be protected from stress. We ask here whether differentiation of progenitor cells to neurones is accompanied by up-regulation of Hsp72, with acquisition of enhanced thermotolerance. Human neuroblastoma SH-SY5Y cells were propagated in an undifferentiated form and subsequently differentiated into neurone-like cells. Thermotolerance tests were carried out by exposure of cells to various temperatures, monitoring nuclear morphology as index of cell death. Abundance of Hsp72 was measured in cell lysates by western immunoblotting. The differentiation of SH-SY5Y cells was accompanied by increased expression of Hsp72. Further, in both cell states, exposure to mild hyperthermic stress (43°C for 30 min) increased Hsp72 expression. After differentiation, SH-SY5Y cells were more resistant to hyperthermic stress compared to their undifferentiated state, correlating with levels of Hsp72. Stable exogenous expression of Hsp72 in SH-SY5Y cells (transfected line 5YHSP72.1, containing mildly elevated levels of Hsp72), led to enhanced resistance to hyperthermic stress. Hsp72 was found to be inducible in undifferentiated 5YHSP72.1 cells; such heat-treated cells displayed enhanced thermotolerance. Treatment of cells with KNK437, a suppressor of Hsp72 induction, resulted in acute thermosensitisation of all cell types tested here. Hsp72 has a major role in the enhanced hyperthermic resistance acquired during neuronal differentiation of SH-SY5Y cells. These findings model the requirement in intact organisms for highly differentiated neurones to be specially protected against thermal stress.

White Shrimp Litopenaeus vannamei That Have Received Gracilaria tenuistipitata Extract Show Early Recovery of Immune Parameters after Ammonia Stressing

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Yu-Yuan Chen

2015-06-01

Full Text Available White shrimp Litopenaeus vannamei immersed in seawater (35‰ containing Gracilaria tenuistipitata extract (GTE at 0 (control, 400, and 600 mg/L for 3 h were exposed to 5 mg/L ammonia-N (ammonia as nitrogen, and immune parameters including hyaline cells (HCs, granular cells (GCs, including semi-granular cells, total hemocyte count (THC, phenoloxidase (PO activity, respiratory bursts (RBs, superoxide dismutase (SOD activity, lysozyme activity, and hemolymph protein level were examined 24~120 h post-stress. The immune parameters of shrimp immersed in 600 mg/L GTE returned to original values earlier, at 96~120 h post-stress, whereas in control shrimp they did not. In another experiment, shrimp were immersed in seawater containing GTE at 0 and 600 mg/L for 3 h and examined for transcript levels of immune-related genes at 24 h post-stress. Transcript levels of lipopolysaccharide and β-1,3-glucan binding protein (LGBP, peroxinectin (PX, cytMnSOD, mtMnSOD, and HSP70 were up-regulated at 24 h post-stress in GTE receiving shrimp. We concluded that white shrimp immersed in seawater containing GTE exhibited a capability for maintaining homeostasis by regulating cellular and humoral immunity against ammonia stress as evidenced by up-regulated gene expression and earlier recovery of immune parameters.

White Shrimp Litopenaeus vannamei That Have Received Gracilaria tenuistipitata Extract Show Early Recovery of Immune Parameters after Ammonia Stressing.

Science.gov (United States)

Chen, Yu-Yuan; Chen, Jiann-Chu; Lin, Yong-Chin; Yeh, Su-Tuen; Huang, Chien-Lun

2015-06-05

White shrimp Litopenaeus vannamei immersed in seawater (35‰) containing Gracilaria tenuistipitata extract (GTE) at 0 (control), 400, and 600 mg/L for 3 h were exposed to 5 mg/L ammonia-N (ammonia as nitrogen), and immune parameters including hyaline cells (HCs), granular cells (GCs, including semi-granular cells), total hemocyte count (THC), phenoloxidase (PO) activity, respiratory bursts (RBs), superoxide dismutase (SOD) activity, lysozyme activity, and hemolymph protein level were examined 24~120 h post-stress. The immune parameters of shrimp immersed in 600 mg/L GTE returned to original values earlier, at 96~120 h post-stress, whereas in control shrimp they did not. In another experiment, shrimp were immersed in seawater containing GTE at 0 and 600 mg/L for 3 h and examined for transcript levels of immune-related genes at 24 h post-stress. Transcript levels of lipopolysaccharide and β-1,3-glucan binding protein (LGBP), peroxinectin (PX), cytMnSOD, mtMnSOD, and HSP70 were up-regulated at 24 h post-stress in GTE receiving shrimp. We concluded that white shrimp immersed in seawater containing GTE exhibited a capability for maintaining homeostasis by regulating cellular and humoral immunity against ammonia stress as evidenced by up-regulated gene expression and earlier recovery of immune parameters.

Music class lower students' stress level

OpenAIRE

服部, 安里; 豊島, 久美子; 福井, 一

2015-01-01

This study has researched on psychological and steroid hormonal effect upon junior-high school students through school music lesson: 1. Music listening, 2. Choir singing. The result showed a significant decrease in cortisol. The study also had conducted a survey about participants' musical preference and their stress level (STAIC – II), which resulted that higher the stress level, more musical activity was willingly conducted. These outcomes suggest that school music lessons can lessen stude...

Stress corrosion cracking evaluation of precipitation-hardening stainless steel

Science.gov (United States)

Humphries, T. S.; Nelson, E. E.

1970-01-01

Accelerated test program results show which precipitation hardening stainless steels are resistant to stress corrosion cracking. In certain cases stress corrosion susceptibility was found to be associated with the process procedure.

Hippocampal Structural Plasticity Accompanies the Resulting Contextual Fear Memory Following Stress and Fear Conditioning

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Giachero, Marcelo; Calfa, Gaston D.; Molina, Victor A.

2013-01-01

The present research investigated the resulting contextual fear memory and structural plasticity changes in the dorsal hippocampus (DH) following stress and fear conditioning. This combination enhanced fear retention and increased the number of total and mature dendritic spines in DH. Intra-basolateral amygdala (BLA) infusion of midazolam prior to…

Posttraumatic stress disorder in new mothers: results from a two-stage U.S. national survey.

Science.gov (United States)

Beck, Cheryl Tatano; Gable, Robert K; Sakala, Carol; Declercq, Eugene R

2011-09-01

Prevalence rates of women in community samples who screened positive for meeting the DSM-IV criteria for posttraumatic stress disorder after childbirth range from 1.7 to 9 percent. A positive screen indicates a high likelihood of this postpartum anxiety disorder. The objective of this analysis was to examine the results that focus on the posttraumatic stress disorder data obtained from a two-stage United States national survey conducted by Childbirth Connection: Listening to Mothers II (LTM II) and Listening to Mothers II Postpartum Survey (LTM II/PP). In the LTM II study, 1,373 women completed the survey online, and 200 mothers were interviewed by telephone. The same mothers were recontacted and asked to complete a second questionnaire 6 months later and of those, 859 women completed the online survey and 44 a telephone interview. Data obtained from three instruments are reported in this article: Posttraumatic Stress Disorder Symptom Scale-Self Report (PSS-SR), Postpartum Depression Screening Scale (PDSS), and the Patient Health Questionnaire-2 (PHQ-2). Nine percent of the sample screened positive for meeting the diagnostic criteria of posttraumatic stress disorder after childbirth as determined by responses on the PSS-SR. A total of 18 percent of women scored above the cutoff score on the PSS-SR, which indicated that they were experiencing elevated levels of posttraumatic stress symptoms. The following variables were significantly related to elevated posttraumatic stress symptoms levels: low partner support, elevated postpartum depressive symptoms, more physical problems since birth, and less health-promoting behaviors. In addition, eight variables significantly differentiated women who had elevated posttraumatic stress symptom levels from those who did not: no private health insurance, unplanned pregnancy, pressure to have an induction and epidural analgesia, planned cesarean birth, not breastfeeding as long as wanted, not exclusively breastfeeding at 1 month

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

Science.gov (United States)

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mean wall-shear stress measurements using the micro-pillar shear-stress sensor MPS3

International Nuclear Information System (INIS)

Große, S; Schröder, W

2008-01-01

A new sensor to measure the mean turbulent wall-shear stress in turbulent flows is described. The wall-shear stress sensor MPS 3 has been tested in a well-defined fully developed turbulent pipe flow at Reynolds numbers Re b based on the bulk velocity U b and the pipe diameter D in the range of Re b = 10 000–20 000. The results demonstrate a convincing agreement of the mean wall-shear stress obtained with the new sensor technique with analytical and experimental results from the literature. The sensor device consists of a flexible micro-pillar that extends from the wall into the viscous sublayer. Bending due to the exerting fluid forces, the pillar-tip deflection serves as a measure for the local wall-shear stress. The sensor concept, calibration techniques, the achievable accuracy and error estimates, the fields of application and the sensor limits will be discussed. Furthermore, a first estimate of the pillar dynamic response will be derived showing the potential of the sensor to also measure the turbulent fluctuating wall-shear stress

Perceived life stress exposure modulates reward-related medial prefrontal cortex responses to acute stress in depression.

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Kumar, Poornima; Slavich, George M; Berghorst, Lisa H; Treadway, Michael T; Brooks, Nancy H; Dutra, Sunny J; Greve, Douglas N; O'Donovan, Aoife; Bleil, Maria E; Maninger, Nicole; Pizzagalli, Diego A

2015-07-15

Major depressive disorder (MDD) is often precipitated by life stress and growing evidence suggests that stress-induced alterations in reward processing may contribute to such risk. However, no human imaging studies have examined how recent life stress exposure modulates the neural systems that underlie reward processing in depressed and healthy individuals. In this proof-of-concept study, 12 MDD and 10 psychiatrically healthy individuals were interviewed using the Life Events and Difficulties Schedule (LEDS) to assess their perceived levels of recent acute and chronic life stress exposure. Additionally, each participant performed a monetary incentive delay task under baseline (no-stress) and stress (social-evaluative) conditions during functional MRI. Across groups, medial prefrontal cortex (mPFC) activation to reward feedback was greater during acute stress versus no-stress conditions in individuals with greater perceived stressor severity. Under acute stress, depressed individuals showed a positive correlation between perceived stressor severity levels and reward-related mPFC activation (r=0.79, p=0.004), whereas no effect was found in healthy controls. Moreover, for depressed (but not healthy) individuals, the correlations between the stress (r=0.79) and no-stress (r=-0.48) conditions were significantly different. Finally, relative to controls, depressed participants showed significantly reduced mPFC gray matter, but functional findings remained robust while accounting for structural differences. Small sample size, which warrants replication. Depressed individuals experiencing greater recent life stress recruited the mPFC more under stress when processing rewards. Our results represent an initial step toward elucidating mechanisms underlying stress sensitization and recurrence in depression. Copyright © 2015 Elsevier B.V. All rights reserved.

Influence of gender and stress on the volatile sulfur compounds and stress biomarkers production.

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Lima, P O; Calil, C M; Marcondes, F K

2013-05-01

Stress and menstrual cycle have been described as factors influencing bad breath, as they can alter oral homeostasis and contribute to the production of volatile sulfur compounds (VSC). Considering that the experimenter's and volunteer's gender may influence the volunteer's responses to stress, the aim of this work was to evaluate the influence of stress and gender on the production of VSC and salivary biomarkers. The experimental acute stress was induced by the Video-Recorded Stroop Color-Word Test (VRSCWT). The VSC, salivary proteins, and cardiovascular parameters were measured before and after VRSCWT. The VRSCWT induced significant increase in total VSC, hydrogen sulfide, and blood pressure values in men and women. Women presented higher values of both these compounds than men. The increase in systolic blood pressure was more pronounced when subjects were evaluated by an experimenter of the opposite gender. When women were evaluated by a member of the opposite gender, they showed significant increases in salivary alpha-amylase and cortisol compared with baseline values. Thus, the results showed that VRSCWT induced acute stress, which increased VSC production, and these effects were shown to be influenced by the gender. © 2012 John Wiley & Sons A/S.

The Relationships among Perfectionism, Acculturation, and Stress in Asian International Students

Science.gov (United States)

Nilsson, Johanna E.; Butler, Jenay; Shouse, Sarah; Joshi, Chetan

2008-01-01

This study examined relationships among perfectionism, acculturation, and stress in 76 Asian international students. Results showed that perfectionism and acculturation predicted stress, together accounting for 50% of the variance in stress. Furthermore, acculturation explained students' experience of stress above and beyond perfectionism, and 1…

Residual stress in Ni-W electrodeposits

DEFF Research Database (Denmark)

Mizushima, Io; Tang, Peter Torben; Hansen, Hans Nørgaard

2006-01-01

In the present work, the residual stress in Ni–W layers electrodeposited from electrolytes based on NiSO4 and Na2WO4, is investigated. Citrate, glycine and triethanolamine were used as complexing agents, enabling complex formation between the nickel ion and tungstate. The results show that the type...... of complexing agent and the current efficiency have an influence on the residual stress. In all cases, an increase in tensile stress in the deposit with time after deposition was observed. Pulse plating could improve the stress level for the electrolyte containing equal amounts of citrate...

Is stress affecting our ability to tune into others? Evidence for gender differences in the effects of stress on self-other distinction.

Science.gov (United States)

Tomova, L; von Dawans, B; Heinrichs, M; Silani, G; Lamm, C

2014-05-01

Stress is a ubiquitous challenge in society as we consistently interact with others under the influence of stress. Distinguishing self- from other-related mental representations plays an important role for social interactions, and is a prerequisite for crucial social skills such as action understanding, empathy, and mentalizing. Little is known, however, about the effects of stress on self-other distinction. We assessed how acute stress impacts self-other distinction in the perceptual-motor, the affective, and the cognitive domain, in a male and female sample. In all domains, the results show opposing effects of stress on the two genders: while women showed increases in self-other distinction, men showed decreases. Our findings suggest that women flexibly disambiguate self and other under stress, enabling accurate social responses, while men respond with increased egocentricity and less adaptive regulation. This has crucial implications for explaining gender differences in social skills such as empathy and prosociality. Copyright © 2014 Elsevier Ltd. All rights reserved.

Low maternal care exacerbates adult stress susceptibility in the chronic mild stress rat model of depression

DEFF Research Database (Denmark)

Henningsen, Kim; Johannesen, Mads Dyrvig; Bouzinova, Elena

2012-01-01

In the present study we report the finding that the quality of maternal care, in early life, increased the susceptibility to stress exposure in adulthood, when rats were exposed to the chronic mild stress paradigm. Our results indicate that high, as opposed to low maternal care, predisposed rats...... to a differential stress-coping ability. Thus rats fostered by low maternal care dams became more prone to adopt a stress-susceptible phenotype developing an anhedonic-like condition. Moreover, low maternal care offspring had lower weight gain and lower locomotion, with no additive effect of stress. Subchronic...... exposure to chronic mild stress induced an increase in faecal corticosterone metabolites, which was only significant in rats from low maternal care dams. Examination of glucocorticoid receptor exon 17 promoter methylation in unchallenged adult, maternally characterized rats, showed an insignificant...

Full-field stress determination in photoelasticity with phase shifting technique

Science.gov (United States)

Guo, Enhai; Liu, Yonggang; Han, Yongsheng; Arola, Dwayne; Zhang, Dongsheng

2018-04-01

Photoelasticity is an effective method for evaluating the stress and its spatial variations within a stressed body. In the present study, a method to determine the stress distribution by means of phase shifting and a modified shear-difference is proposed. First, the orientation of the first principal stress and the retardation between the principal stresses are determined in the full-field through phase shifting. Then, through bicubic interpolation and derivation of a modified shear-difference method, the internal stress is calculated from the point with a free boundary along its normal direction. A method to reduce integration error in the shear difference scheme is proposed and compared to the existing methods; the integration error is reduced when using theoretical photoelastic parameters to calculate the stress component with the same points. Results show that when the value of Δx/Δy approaches one, the error is minimum, and although the interpolation error is inevitable, it has limited influence on the accuracy of the result. Finally, examples are presented for determining the stresses in a circular plate and ring subjected to diametric loading. Results show that the proposed approach provides a complete solution for determining the full-field stresses in photoelastic models.

Age, Stress, and Emotional Complexity: Results from Two Studies of Daily Experiences

Science.gov (United States)

Scott, Stacey B.; Sliwinski, Martin J.; Mogle, Jacqueline A.; Almeida, David M.

2014-01-01

Experiencing positive and negative emotions together (i.e., co-occurrence) has been described as a marker of positive adaptation during stress and a strength of socio-emotional aging. Using data from daily diary (N=2,022; ages 33-84) and ecological momentary assessment (N=190; ages 20-80) studies, we evaluate the utility of a common operationalization of co-occurrence, the within-person correlation between positive affect (PA) and negative affect (NA). Then we test competing predictions regarding when co-occurrence will be observed and whether age differences will be present. Results indicate that the correlation is not an informative indicator of co-occurrence. Although correlations were stronger and more negative when stressors occurred (typically interpreted as lower co-occurrence), objective counts of emotion reports indicated that positive and negative emotions were more 3 to 4 times likely to co-occur when stressors were reported. This suggests that co-occurrence reflects the extent to which negative emotions intrude on typically positive emotional states, rather than the extent to which people maintain positive emotions during stress. The variances of both PA and NA increased at stressor reports, indicating that individuals reported a broader not narrower range of emotion during stress. Finally, older age was associated with less variability in NA and a lower likelihood of co-occurring positive and negative emotions. In sum, these findings cast doubt on the utility of the PA-NA correlation as an index of emotional co-occurrence, and question notion that greater emotional cooccurrence represents either a typical or adaptive emotional state in adults. PMID:25244477

Effect of degree of lipomobilization on results of glucose test in dairy cows in heat stress

Directory of Open Access Journals (Sweden)

Cincović M.R.

2012-01-01

Full Text Available Cows exposed to heat stress exhibit a decreased ability to mobilize lipids due to increased sensitivity to insulin, which is expressed in a decreased concentration of NEFA. However, certain cows can preserve the level of lipid mobilization after adapting to heat stress. We assumed that cows that have a preserved ability to mobilize lipids are less sensitive to insulin and that they have a lower tolerance for glucose. The aim of this work was to compare the results of an intravenous glucose tolerance test in cows that exhibited, in prolonged heat stress, a decreased (NEFA0.30 mmol/l ability for lipid mobilization. Glucose concentration and NEFA concentration were measured following intravenous application of glucose. The mean glycaemic index value did not differ statistically significantly between the two groups of cows at 10, 15 and 20 minutes after glucose application (p>0.05, but there was a tendency at 10 and 15 minutes for the glycaemia to be higher in cows with preserved lipomobilization (p<0.1. At 30, 60 and 90 minutes after glucose application, glycaemia was statistically significantly higher (p<0.01; p<0.05 and p<0.05 in the group of cows with preserved lipomobilization. The glycaemic index values (mmol/l shown in the same order (30, 60 and 90 minutes were as follows 9.91±0.21: 9.23±0.41; 5.41±0.5: 4.67±0.33 and 4.31±0.39: 3.47±0.37. The mean value for NEFA concentration in samples originating from the two experimental groups of cows did not differ statistically significantly following glucose application. The NEFA concentration showed a tendency to be higher in cows with preserved lipid mobilization in comparison with cows with decreased lipomobilization at 20 and 30 minutes after glucose application (p<0.1. Following the intravenous glucose tolerance test, NEFA and glucose concentrations were in a significant negative correlation, and that correlation was more expressed in cows with decreased lipomobilization. Cows with preserved

Medication overuse, healthy lifestyle behaviour and stress in chronic headache: Results from a population-based representative survey.

Science.gov (United States)

Westergaard, Maria Lurenda; Glümer, Charlotte; Hansen, Ebba Holme; Jensen, Rigmor Højland

2016-01-01

This cross-sectional study investigated associations between chronic headache (CH) with and without medication overuse, healthy lifestyle behaviour, and stress. Questionnaires were sent to 129,150 adults. Those with headache ≥15 days per month for three months were classified as having CH then further described as having medication-overuse headache (MOH) or CH without medication overuse. Associations between headache and daily smoking, physical inactivity, obesity, excessive drinking, illicit drug use, and high stress were analysed by logistic regression. CH with and without medication overuse (prevalence 1.8% and 1.6%, respectively) had strong, graded associations with stress. Associations with daily smoking, physical inactivity, and obesity were significant only for MOH. Odds for MOH were highest among people who had all three factors compared to those who had none (OR 2.8 in women and 5.1 in men). High stress plus any of these three factors had synergistic effects in MOH but not clearly in those who had CH without overuse. Associations between CH subtypes and excessive drinking or illicit drug use were not statistically significant. Results suggest strong links between healthy lifestyle behaviour and stress in MOH. Stress reduction and promoting healthy behaviour are highly relevant in MOH management. © International Headache Society 2015.

Stress, fatigue, and sleep quality leading up to and following a stressful life event.

Science.gov (United States)

Van Laethem, Michelle; Beckers, Debby G J; Dijksterhuis, Ap; Geurts, Sabine A E

2017-10-01

This study aims to examine (a) the time course of stress, fatigue, and sleep quality among PhD students awaiting a stressful event and (b) whether daily anticipation of this event influences day-level stress, fatigue, and sleep quality. Forty-four PhD students completed evening and morning questionnaires on eight days from 1 month before their dissertation defense until one month thereafter. Results showed increased stress leading up to the defense, while fatigue and sleep quality remained unchanged. Comparing the night before the defense with the night after, stress rapidly decreased, whereas fatigue and sleep quality increased. Following the defense, stress and sleep quality remained stable, whereas fatigue declined. Stress 1 month before the defense was higher than 1 month thereafter. Regarding day-level relations, stress was adversely affected by negative anticipation and favorably by positive outcome expectancy, whereas positive anticipation had no influence. Positive outcome expectancy was an important predictor of improved sleep quality. We conclude that stress may be elevated long before a stressful event takes place but that one can recover rather quickly from temporary stress. Positive outcome expectancy of a stressful event may be an important predictor of reduced day-level stress and improved day-level sleep quality leading up to a stressful event. Copyright © 2016 John Wiley & Sons, Ltd.

In-situ stress measurements - results of experiments performed at the ASSE salt mine - Federal Republic of Germany

International Nuclear Information System (INIS)

Feddersen, H.K.

1989-01-01

High-level nuclear wastes are heat generating wastes. Heat will be transferred to the surrounding salt formation. This heating of the host rock will result in an increased temperature and in stress changes. From 1983 through 1985 two underground tests were conducted in the Asse Salt Mine (Federal Republic of Germany) in which, among others, thermally induced stress changes were investigated. These tests are discussed in this paper

No effects of psychosocial stress on intertemporal choice.

Directory of Open Access Journals (Sweden)

Johannes Haushofer

Full Text Available Intertemporal choices - involving decisions which trade off instant and delayed outcomes - are often made under stress. It remains unknown, however, whether and how stress affects intertemporal choice. We subjected 142 healthy male subjects to a laboratory stress or control protocol, and asked them to make a series of intertemporal choices either directly after stress, or 20 minutes later (resulting in four experimental groups. Based on theory and evidence from behavioral economics and cellular neuroscience, we predicted a bidirectional effect of stress on intertemporal choice, with increases in impatience or present bias immediately after stress, but decreases in present bias or impatience when subjects are tested 20 minutes later. However, our results show no effects of stress on intertemporal choice at either time point, and individual differences in stress reactivity (changes in stress hormone levels over time are not related to individual differences in intertemporal choice. Together, we did not find support for the hypothesis that psychosocial laboratory stressors affect intertemporal choice.

Perception of stress among aviation flight students

Science.gov (United States)

Bhattacharya, Amrita

There have been many studies related to stress among college students and the purpose of this research was to determine what causes stress among the student pilots enrolled in the Middle Tennessee State University (MTSU) flight program, also to find out what students think could be some possible ways to reduce their stress, and to compare the results with a previous study conducted by South Illinois University. The survey designed by Robertson and Ruiz (2010) was administered to MTSU students so that a comparison could be done between MTSU and SIU, as SIU used the same survey form. Results of the study showed that flight students are exposed to similar stress at both universities, but some of the factors that cause stress are different between MTSU and SIU students.

Experimental variation of social stress in virtual reality - Feasibility and first results in patients with psychotic disorders.

Science.gov (United States)

Hesse, Klaus; Schroeder, Philipp A; Scheeff, Jonathan; Klingberg, Stefan; Plewnia, Christian

2017-09-01

Social interaction might lead to increased stress levels in patients with psychotic disorders. Impaired social stress tolerance is critical for social functioning and closely linked with symptom relapse and hospitalization. We present an interactive office built-up in virtual reality (VR). Patients with psychotic disorders (PP, N = 26 including N = 5 dropouts) and matched healthy controls (HC, N = 20) were examined with a VR simulating an open-plan office. In a randomized, controlled cross-over design, participants were introduced to virtual co-workers (avatars) and requested to ask them for task assistance. Social feedback in each of the two sessions was either cooperative or rejective in randomized order. The office environment was tolerable for most PP and all HC, five PP and none of the HC dropped out for any reason. Drop-outs reported simulator sickness, influence on thoughts and symptom exacerbations. Statistical trends indicated heightened paranoid ideations for PP after social rejection. State measures of paranoid ideations showed high convergent validity with conventional measures of delusions. Of note, measures of presence were higher for PP than for HC. The exploratory design limits the robustness of the findings. Only statistical trends on paranoid ideation were found. The use of VR to assess the effects of social rejection is feasible and tolerable for most PP (87%). However, its implementation for PP is challenged by increased simulator sickness and an additional stress load for some patients. Further studies continuing on these first results that point towards an increased paranoid ideation evoked by negative social feedback and generally higher subjective presence are needed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Psychophysiological responses to stress after stress management training in patients with rheumatoid arthritis.

Directory of Open Access Journals (Sweden)

Sabine J M de Brouwer

Full Text Available BACKGROUND: Stress management interventions may prove useful in preventing the detrimental effects of stress on health. This study assessed the effects of a stress management intervention on the psychophysiological response to stress in patients with rheumatoid arthritis (RA. METHODS: Seventy-four patients with RA, who were randomly assigned to either a control group or a group that received short-term stress management training, performed a standardized psychosocial stress task (Trier Social Stress Test; TSST 1 week after the stress management training and at a 9-week follow-up. Psychological and physical functioning, and the acute psychophysiological response to the stress test were assessed. RESULTS: Patients in the intervention group showed significantly lower psychological distress levels of anxiety after the training than did the controls. While there were no between-group differences in stress-induced tension levels, and autonomic (α-amylase or endocrine (cortisol responses to the stress test 1 week after the intervention, levels of stress-induced tension and cortisol were significantly lower in the intervention group at the 9-week follow-up. Overall, the response to the intervention was particularly evident in a subgroup of patients with a psychological risk profile. CONCLUSION: A relatively short stress management intervention can improve psychological functioning and influences the psychophysiological response to stress in patients with RA, particularly those psychologically at risk. These findings might help understand how stress can affect health and the role of individual differences in stress responsiveness. TRIAL REGISTRATION: TrialRegister.nl NTR1193.

A study of x-ray microbeam stress measurement for local area

International Nuclear Information System (INIS)

Natsume, Yoshitaka; Miyakawa, Susumu

1987-01-01

A new type X-ray microbeam equipment which is capable of three-dimensional oscillation at an X-ray radiation position was used to measure the residual stress of pure iron powder and bending plate specimens as well as that in the vicinity of fatigue crack tip of 1/2 CT specimen. The results obtained are summerized as follows. (1) Diffraction profiles of pure iron powder with diameter 0.02 ∼ 0.03 μm particle size obtained by the present microbeam technique in the beam area of 80 μm in diamether and measuring time more than 800 sec showed Kα 1 and Kα 2 peaks clearly, so that these profiles are good enough for stress measurement. (2) The measured stress of pure iron powder with diameter 10 ∼ 25 μm particle size in the beam area of 80 μm in diameter was not equal to 0 MPa. The measured stress varied greatly and was independent of measuring time. (3) The measured stress of pure iron powder with diameter 0.02 ∼ 0.03 μm particle size in the beam area of 80 μm in diameter was almost 1 MPa, which shows the good accuracy of this X-ray micro-beam equipment. (4) The relation between the X-ray measured stress and the mechanically applied stress showed good agreement. (5) The distribution of residual stress at the vicinity of fatigue crack tip showed that the residual stress at the fatigue crack tip was compression and the residual stress in front of crack tip was tension. This tensile residual stress in front of crack tip existed in the area from 0.02 mm to 2 mm. (6) The above results show that the present equipment is advantageous in the investigation of local stress, shortening the measuring time without sacrificing the accuracy. (author)

Electronic processes in uniaxially stressed p-type germanium

Energy Technology Data Exchange (ETDEWEB)

Dubon, Jr., Oscar Danilo [Univ. of California, Berkeley, CA (United States)

1996-02-01

Effect of uniaxial stress on acceptor-related electronic processes in Ge single crystals doped with Ga, Be, and Cu were studied by Hall and photo-Hall effect measurements in conjunction with infrared spectroscopy. Stress dependence of hole lifetime in p-type Ge single crystals is used as a test for competing models of non-radiative capture of holes by acceptors. Photo-Hall effect shows that hole lifetime in Ga- and Be-doped Ge increases by over one order of magnitude with uniaxial stress at liq. He temps. Photo-Hall of Ge:Be shows a stress-induced change in the temperature dependence of hole lifetime. This is consistent with observed increase of responsivity of Ge:Ga detectors with uniaxial stress. Electronic properties of Ge:Cu are shown to change dramatically with uniaxial stress; the results provide a first explanation for the performance of uniaxially stressed, Cu-diffused Ge:Ga detectors which display a high conductivity in absence of photon signal and therefore have poor sensitivity.

Transcriptomic and metabolomic analysis of Yukon Thellungiella plants grown in cabinets and their natural habitat show phenotypic plasticity

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Guevara David R

2012-10-01

Full Text Available Abstract Background Thellungiella salsuginea is an important model plant due to its natural tolerance to abiotic stresses including salt, cold, and water deficits. Microarray and metabolite profiling have shown that Thellungiella undergoes stress-responsive changes in transcript and organic solute abundance when grown under controlled environmental conditions. However, few reports assess the capacity of plants to display stress-responsive traits in natural habitats where concurrent stresses are the norm. Results To determine whether stress-responsive changes observed in cabinet-grown plants are recapitulated in the field, we analyzed leaf transcript and metabolic profiles of Thellungiella growing in its native Yukon habitat during two years of contrasting meteorological conditions. We found 673 genes showing differential expression between field and unstressed, chamber-grown plants. There were comparatively few overlaps between genes expressed under field and cabinet treatment-specific conditions. Only 20 of 99 drought-responsive genes were expressed both in the field during a year of low precipitation and in plants subjected to drought treatments in cabinets. There was also a general pattern of lower abundance among metabolites found in field plants relative to control or stress-treated plants in growth cabinets. Nutrient availability may explain some of the observed differences. For example, proline accumulated to high levels in cold and salt-stressed cabinet-grown plants but proline content was, by comparison, negligible in plants at a saline Yukon field site. We show that proline accumulated in a stress-responsive manner in Thellungiella plants salinized in growth cabinets and in salt-stressed seedlings when nitrogen was provided at 1.0 mM. In seedlings grown on 0.1 mM nitrogen medium, the proline content was low while carbohydrates increased. The relatively higher content of sugar-like compounds in field plants and seedlings on low nitrogen

Transcriptomic and metabolomic analysis of Yukon Thellungiella plants grown in cabinets and their natural habitat show phenotypic plasticity

Science.gov (United States)

2012-01-01

Background Thellungiella salsuginea is an important model plant due to its natural tolerance to abiotic stresses including salt, cold, and water deficits. Microarray and metabolite profiling have shown that Thellungiella undergoes stress-responsive changes in transcript and organic solute abundance when grown under controlled environmental conditions. However, few reports assess the capacity of plants to display stress-responsive traits in natural habitats where concurrent stresses are the norm. Results To determine whether stress-responsive changes observed in cabinet-grown plants are recapitulated in the field, we analyzed leaf transcript and metabolic profiles of Thellungiella growing in its native Yukon habitat during two years of contrasting meteorological conditions. We found 673 genes showing differential expression between field and unstressed, chamber-grown plants. There were comparatively few overlaps between genes expressed under field and cabinet treatment-specific conditions. Only 20 of 99 drought-responsive genes were expressed both in the field during a year of low precipitation and in plants subjected to drought treatments in cabinets. There was also a general pattern of lower abundance among metabolites found in field plants relative to control or stress-treated plants in growth cabinets. Nutrient availability may explain some of the observed differences. For example, proline accumulated to high levels in cold and salt-stressed cabinet-grown plants but proline content was, by comparison, negligible in plants at a saline Yukon field site. We show that proline accumulated in a stress-responsive manner in Thellungiella plants salinized in growth cabinets and in salt-stressed seedlings when nitrogen was provided at 1.0 mM. In seedlings grown on 0.1 mM nitrogen medium, the proline content was low while carbohydrates increased. The relatively higher content of sugar-like compounds in field plants and seedlings on low nitrogen media suggests that

Probing Earth's State of Stress

Science.gov (United States)

Delorey, A. A.; Maceira, M.; Johnson, P. A.; Coblentz, D. D.

2016-12-01

The state of stress in the Earth's crust is a fundamental physical property that controls both engineered and natural systems. Engineered environments including those for hydrocarbon, geothermal energy, and mineral extraction, as well those for storage of wastewater, carbon dioxide, and nuclear fuel are as important as ever to our economy and environment. Yet, it is at spatial scales relevant to these activities where stress is least understood. Additionally, in engineered environments the rate of change in the stress field can be much higher than that of natural systems. In order to use subsurface resources more safely and effectively, we need to understand stress at the relevant temporal and spatial scales. We will present our latest results characterizing the state of stress in the Earth at scales relevant to engineered environments. Two important components of the state of stress are the orientation and magnitude of the stress tensor, and a measure of how close faults are to failure. The stress tensor at any point in a reservoir or repository has contributions from both far-field tectonic stress and local density heterogeneity. We jointly invert seismic (body and surface waves) and gravity data for a self-consistent model of elastic moduli and density and use the model to calculate the contribution of local heterogeneity to the total stress field. We then combine local and plate-scale contributions, using local indicators for calibration and ground-truth. In addition, we will present results from an analysis of the quantity and pattern of microseismicity as an indicator of critically stressed faults. Faults are triggered by transient stresses only when critically stressed (near failure). We show that tidal stresses can trigger earthquakes in both tectonic and reservoir environments and can reveal both stress and poroelastic conditions.

Prediction of residual stress distributions due to surface machining and welding and crack growth simulation under residual stress distribution

International Nuclear Information System (INIS)

Ihara, Ryohei; Katsuyama, JInya; Onizawa, Kunio; Hashimoto, Tadafumi; Mikami, Yoshiki; Mochizuki, Masahito

2011-01-01

Research highlights: → Residual stress distributions due to welding and machining are evaluated by XRD and FEM. → Residual stress due to machining shows higher tensile stress than welding near the surface. → Crack growth analysis is performed using calculated residual stress. → Crack growth result is affected machining rather than welding. → Machining is an important factor for crack growth. - Abstract: In nuclear power plants, stress corrosion cracking (SCC) has been observed near the weld zone of the core shroud and primary loop recirculation (PLR) pipes made of low-carbon austenitic stainless steel Type 316L. The joining process of pipes usually includes surface machining and welding. Both processes induce residual stresses, and residual stresses are thus important factors in the occurrence and propagation of SCC. In this study, the finite element method (FEM) was used to estimate residual stress distributions generated by butt welding and surface machining. The thermoelastic-plastic analysis was performed for the welding simulation, and the thermo-mechanical coupled analysis based on the Johnson-Cook material model was performed for the surface machining simulation. In addition, a crack growth analysis based on the stress intensity factor (SIF) calculation was performed using the calculated residual stress distributions that are generated by welding and surface machining. The surface machining analysis showed that tensile residual stress due to surface machining only exists approximately 0.2 mm from the machined surface, and the surface residual stress increases with cutting speed. The crack growth analysis showed that the crack depth is affected by both surface machining and welding, and the crack length is more affected by surface machining than by welding.

Interactions between the phase stress and the grain-orientation-dependent stress in duplex stainless steel during deformation

International Nuclear Information System (INIS)

Jia, N.; Peng, R. Lin; Wang, Y.D.; Chai, G.C.; Johansson, S.; Wang, G.; Liaw, P.K.

2006-01-01

The development of phase stress and grain-orientation-dependent stress under uniaxial compression was investigated in a duplex stainless steel consisting of austenite and ferrite. Using in situ neutron diffraction measurements, the strain response of several h k l planes to the applied compressive stress was mapped as a function of applied stress and sample direction. Analysis based on the experimental results and elastoplastic self-consistent simulations shows that phase stresses of thermal origin further increase during elastic loading but decrease with increased plastic deformation. Grain-orientation-dependent stresses become significant in both austenite and ferrite after loading into the plastic region. After unloading from the plastic regime, a considerable intergranular stress remains in the austenitic phase and dominates over the phase stress. This study provides fundamental experimental inputs for future micromechanical modeling aiming at the evaluation and prediction of the mechanical performance of multiphase materials

Assessment the effect of NO inhibition on hippocampal normetanephrine level in stress and non-stress conditions in adult male rats

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Hana Molahoveizeh

2016-01-01

Full Text Available Background: Nitric oxide (NO has a role in the regulation of neurotransmitters release such as norepinephrine, in the hippocampus.Normetanephrine (NMN is a metabolite of norepinephrine created by action of catechol-O-methyl transferase (COMT on norepinephrine. Several studies have shown that various stresses increased release of norepinephrine and its metabolites. Therefore in the present study, the role of Nitric oxide in regulation of norepinephrine release and its metabolism was investigated by administration of L-NAME (NO synthase inhibitor in stressed and non-stressed rats. Materials and Methods: For this purpose, 50 adult rats were divided into 10 groups, of which 5 groups were exposed to restraint stress while another 5 groups were without stress. These two set of groups included intact, saline and L-NAME (20, 40, 80 mg/kg. Thirty minutes after intraperituneal injection of L-NAME, brains removed, the hippocampus dissected, weighed, homogenized and centrifuged then amount of NMN measured by ELISA kit. Results: The results showed that in non-stressed condition amount of NMN were significantly increased in group that received L-NAME (80 mg/kg in comparison with other groups but in stress condition, amount of NMN was significantly decreased in groups that received L-NAME (20,40,80 mg/kg, in comparison with control and saline groups. Comparison between stress and non-stressed groups showed that stress alone cause an increase in amount of NMN in control and saline groups. Conclusion: In conclusion, NO synthesis inhibition produced opposite responses with respect to NMN amount in the presence or absence of stress, and probably L-NAME preventing the effect of stress on increasing NMN levels mediated by nitrergic pathway.

Stress and Subjective Age: Those With Greater Financial Stress Look Older.

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Agrigoroaei, Stefan; Lee-Attardo, Angela; Lachman, Margie E

2017-12-01

Subjective indicators of age add to our understanding of the aging process beyond the role of chronological age. We examined whether financial stress contributes to subjective age as rated by others and the self. The participants ( N = 228), aged 26-75, were from a Boston area satellite of the Midlife in the United States (MIDUS) longitudinal study. Participants reported how old they felt and how old they thought they looked, and observers assessed the participants' age based on photographs (other-look age), at two occasions, an average of 10 years apart. Financial stress was measured at Time 1. Controlling for income, general stress, health, and attractiveness, participants who reported higher levels of financial stress were perceived as older than their actual age to a greater extent and showed larger increases in other-look age over time. We consider the results on accelerated aging of appearance with regard to their implications for interpersonal interactions and in relation to health.

Bridging scales of crustal stress patterns using the new World Stress Map

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Heidbach, O.; Rajabi, M.; Cui, X.; Fuchs, K. W.; Mueller, B.; Reinecker, J.; Reiter, K.; Tingay, M. R. P.; Wenzel, F.; Xie, F.; Ziegler, M.; Zoback, M. D.; Zoback, M. L.

2017-12-01

Knowledge of the contemporary crustal stress field is a key parameter for the understanding of geodynamic processes such as global plate tectonics and the earthquake cycle. It is also an essential parameter for our sustainable and safe usage of Earth's resources, which is a major challenge for energy security in the 21st century. Since 1986, the World Stress Map (WSM) project has systematically compiled present-day stress information and provides a unique public domain global database. It is a long-term project based on an international network of partners from academia and industry. All data are public and available on the project website at world-stress-map.org. For the 30th anniversary of the project a new database has been compiled, containing double the amount of data records (n=42,870) including new data records from almost 4,000 deep boreholes. The new compilation focused on areas with previously sparse data coverage in order to resolve the stress pattern on different spatial scales. The significantly higher data density can now be used to resolve stress pattern heterogeneities on regional and local scales, as well as with depth in some regions. We present three results derived from the new WSM compilation: 1.) The global comparison between absolute plate motion and the mean of the orientation of maximum horizontal stress SHmax on a regular grid shows that there is still a correlation for the North and South America plate, but deviations from this general trend are now also clearly resolved. 2.) The variability of the crustal stress pattern changes when zooming in from plate-wide scale down to basin scale at 100 km. We show examples for Eastern Australia, Oklahoma and Central Europe. This regional and local variability of the stress pattern can be used as a proxy to identify and quantify regional and local stress sources by means of geomechanical-numerical models of the 3D stress tensor. 3.) Finally we present briefly the general concept of a multi-stage 3D

Predischarge stress test after myocardial infarction in the old stage : results and prognostic value

NARCIS (Netherlands)

P.M. Fioretti (Paolo); J.W. Deckers (Jaap); R.W. Brower (Ronald); M.L. Simoons (Maarten); J.A.J.M. Beelen; P.G. Hugenholtz (Paul)

1984-01-01

textabstractThe aim of this study was to evaluate the results of predischarge stress testing in the elderly, and to assess the prognostic value of the test during one-year follow-up. The database consisted of 48 patients older than 64 years of age and 109 patients 55-64 years of age, who survived

Stress associated with caregiving: an examination of the stress process model among Kenyan Luo elders.

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Ice, Gillian H; Sadruddin, Aalyia F A; Vagedes, Amy; Yogo, Jaja; Juma, Elizabeth

2012-06-01

Globally, a growing number of grandparents are caring for their grandchildren. The impact and burden associated with increases in custodial grandparenting, however, may differ by culture. In the United States, the caregiving role has been shown to be a significant source of stress for older adults. In cultures in which grandparents are more commonly involved in the care of young children, however, increasing caregiving roles may not be viewed as stressful. This study examines the impact of caregiving on perceived and physiological measures of stress among 640 Luo elders (60+) in western Kenya, where high HIV prevalence among younger-to-middle aged adults has led to a heavy burden of orphan care. Perceived stress levels were measured using the Luo Perceived Stress Scale (LPSS). Salivary cortisol and casual blood pressure were used as biomarkers of stress. Results were analyzed using random mixed effects models. Overall this study showed that caregivers have higher levels of perceived stress than non-caregivers. For women, household composition, including the number of orphans and adults in the homestead impacted perceived stress. Among men, those who perceived caregiving as burdensome had higher perceived stress. Despite the association between caregiving and perceived stress, there was a minimal relationship between caregiving and the two biomarkers of stress. This may be because caregiving is superimposed onto other stressors and therefore has a minimal physiological impact. These results highlight the importance of local context in determining the impact of the caregiving role on older adult well-being. Copyright © 2012 Elsevier Ltd. All rights reserved.

A study on factors of dissatisfaction and stress of the blacksmiths resulting from the organizational culture in the surgical instrument industry of India.

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Ghosh, Tirthankar; Das, Banibrata; Gangopadhyay, Somnath

2011-07-01

It is important to understand what motivates workers and the extent to which the organization and other contextual variables satisfy them. The aim of the study was to determine factors of dissatisfaction resulting from the organizational culture among the blacksmiths involved in the surgical instrument industry. Fifty male surgical blacksmiths each of the skilled and unskilled groups of the forging section were selected. Organizational Role Stress Scale was used to measure the individuals' role stress and several forms of conflict within an organization. Also, the organizational culture and personal involvement in an organization was measured among the surgical blacksmiths. The mean score for total role stress for Skilled was 71.7 and for unskilled was 77.2. The most frequent type of organizational culture was reported to be hierarchy, both by skilled and unskilled surgical blacksmiths, followed by market and clan culture. This study shows that the skilled surgical blacksmiths have lower level of stress and conflicts in comparison with unskilled surgical blacksmiths. Both skilled and unskilled surgical blacksmiths estimated their level of personal involvement as low and indicated insufficient involvement in work teams. The satisfaction of the employees with their status and role in the organizational culture was also poor for both skilled and unskilled surgical blacksmiths.

[Assessment of stress in childhood: Children's Daily Stress Inventory (Inventario Infantil de Estresores Cotidiano, IIEC)].

Science.gov (United States)

Trianes Torres, María Victoria; Blanca Mena, María José; Fernández Baena, Francisco J; Escobar Espejo, Milagros; Maldonado Montero, Enrique F; Muñoz Sánchez, Angela María

2009-11-01

The present study introduces the Children's Daily Stress Inventory (Inventario Infantil de Estresores Cotidianos, IIEC) as a measure that assesses daily stress in primary school children. The inventory was applied to a sample of 1094 primary school students. The final version includes 25 dichotomic items covering the areas of health, school/peers, and family. The score is obtained by adding the total of positive answers. Analyses of items, reliability and several external pieces of evidence of validity based on relations with other variables are presented. The results show adequate psychometric properties for the assessment of daily stress in children.

Stress "Deafness" Reveals Absence of Lexical Marking of Stress or Tone in the Adult Grammar.

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Hamed Rahmani

Full Text Available A Sequence Recall Task with disyllabic stimuli contrasting either for the location of prosodic prominence or for the medial consonant was administered to 150 subjects equally divided over five language groups. Scores showed a significant interaction between type of contrast and language group, such that groups did not differ on their performance on the consonant contrast, while two language groups, Dutch and Japanese, significantly outperformed the three other language groups (French, Indonesian and Persian on the prosodic contrast. Since only Dutch and Japanese words have unpredictable stress or accent locations, the results are interpreted to mean that stress "deafness" is a property of speakers of languages without lexical stress or tone markings, as opposed to the presence of stress or accent contrasts in phrasal (post-lexical constructions. Moreover, the degree of transparency between the locations of stress/tone and word boundaries did not appear to affect our results, despite earlier claims that this should have an effect. This finding is of significance for speech processing, language acquisition and phonological theory.

Stress in Community Health Agents: a Bioethics Protection Perspective

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Ulysses Rodrigues de Castro

2014-09-01

Full Text Available Health care professionals suffer from both regular job stress and caregiver stress that arises from the neglect of their work situation. As principles of bioethics protection, vertical protection ratio, health policies should also target health professionals. So, this paper seeks to understand the issue of stress in relation to mental health professionals, specifically the community health agents of the Federal District in Brazil. Methods: This study is an exploratory study that adopts a quantitative approach. Data were obtained by a questionnaire, that mesure social, work and stress factors, in 97 community health agents, a different class of health professional. The SPSS 19.0 program was used to mesure the results. Results: The sociodemographic data of respondentes revealed that the majority were women, 40,2% of the group members fall in the age range 30‒39 years, 51% of respondents were married and 57.7% were of middle socioeconomic status. All Pearson correlations were significant at the 0.01 level (two-tailed. The results show that all stressors are negatively correlated with the mental health factors. These results showed that mental health deteriorates with increased stress. The mental health indicators are strongly and positively associated, indicating that individuals with better mental health show greater personal, social and workplace support. Conclusions: The results indicate the need for management changes in the public health sector related to Bioethics Protection, which states that populations vulnerable to work exploitation should be protected by guaranteeing minimum working conditions.

Residual stress in a thick section high strength T-butt weld

International Nuclear Information System (INIS)

Pearce, S.V.; Linton, V.M.; Oliver, E.C.

2008-01-01

Residual stresses in a structure are generated as a result of the various fabrication and welding processes used to make the component. Being able to quantify these residual stresses is a key step in determining the continuing integrity of a structure in service. In this work, the residual stresses around a high strength, quenched and tempered steel T-butt web to curved plate weld have been measured using neutron strain scanning. The results show that the residual stresses near the weld were dominated by the welding residual stresses, while the stresses further from the weld were dominated by the bending residual stresses. The results suggest that the combination of welding-induced residual stress and significant pre-welding residual stress, as in the case of a thick bent section of plate can significantly alter the residual stress profile from that in a flat plate

Chronic stress and neural function: accounting for sex and age.

Science.gov (United States)

Luine, V N; Beck, K D; Bowman, R E; Frankfurt, M; Maclusky, N J

2007-10-01

Cognitive responses to stress follow the temporally dependent pattern originally established by Selye (1) wherein short-term stressors elicit adaptive responses whereas continued stress (chronic) results in maladaptive changes--deleterious effects on physiological systems and impaired cognition. However, this pattern for cognitive effects appears to apply to only half the population (males) and, more specifically, to young, adult males. Females show different cognitive responses to stress. In contrast to impaired cognition in males after chronic stress, female rodents show enhanced performance on the same memory tasks after the same stress. Not only cognition, but anxiety, shows sex-dependent changes following chronic stress--stress is anxiolytic in males and anxiogenic in females. Moreover, behavioral responses to chronic stress are different in developing as well as aging subjects (both sexes) as compared to adults. In aged rats, chronic stress enhances recognition memory in both sexes, does not alter spatial memory, and anxiety effects are opposite to young adults. When pregnant dams are exposed to chronic stress, at adulthood the offspring display yet different consequences of stress on anxiety and cognition, and, in contrast to adulthood when the behavioral effects of stress are reversible, prenatal stress effects appear enduring. Changing levels of estradiol in the sexes over the lifespan appear to contribute to the differences in response to stress. Thus, theories of stress dependent modulations in CNS function--developed solely in male models, focused on peripheral physiological processes and tested in adults--may require revision when applied to a more diverse population (age- and sex-wise) at least in relation to the neural functions of cognition and anxiety. Moreover, these results suggest that other stressors and neural functions should be investigated to determine whether age, sex and gonadal hormones also have an impact.

Age, stress, and emotional complexity: results from two studies of daily experiences.

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Scott, Stacey B; Sliwinski, Martin J; Mogle, Jacqueline A; Almeida, David M

2014-09-01

Experiencing positive and negative emotions together (i.e., co-occurrence) has been described as a marker of positive adaptation during stress and a strength of socioemotional aging. Using data from daily diary (N = 2,022; ages 33-84) and ecological momentary assessment (N = 190; ages 20-80) studies, we evaluate the utility of a common operationalization of co-occurrence, the within-person correlation between positive affect (PA) and negative affect (NA). Then we test competing predictions regarding when co-occurrence will be observed and whether age differences will be present. Results indicate that the correlation is not an informative indicator of co-occurrence. Although correlations were stronger and more negative when stressors occurred (typically interpreted as lower co-occurrence), objective counts of emotion reports indicated that positive and negative emotions were 3 to 4 times more likely to co-occur when stressors were reported. This suggests that co-occurrence reflects the extent to which negative emotions intrude on typically positive emotional states, rather than the extent to which people maintain positive emotions during stress. The variances of both PA and NA increased at stressor reports, indicating that individuals reported a broader not narrower range of emotion during stress. Finally, older age was associated with less variability in NA and a lower likelihood of co-occurring positive and negative emotions. In sum, these findings cast doubt on the utility of the PA-NA correlation as an index of emotional co-occurrence, and question notion that greater emotional co-occurrence represents either a typical or adaptive emotional state in adults. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Cell Wall Metabolism in Response to Abiotic Stress

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Gall, Hyacinthe Le; Philippe, Florian; Domon, Jean-Marc; Gillet, Françoise; Pelloux, Jérôme; Rayon, Catherine

2015-01-01

This review focuses on the responses of the plant cell wall to several abiotic stresses including drought, flooding, heat, cold, salt, heavy metals, light, and air pollutants. The effects of stress on cell wall metabolism are discussed at the physiological (morphogenic), transcriptomic, proteomic and biochemical levels. The analysis of a large set of data shows that the plant response is highly complex. The overall effects of most abiotic stress are often dependent on the plant species, the genotype, the age of the plant, the timing of the stress application, and the intensity of this stress. This shows the difficulty of identifying a common pattern of stress response in cell wall architecture that could enable adaptation and/or resistance to abiotic stress. However, in most cases, two main mechanisms can be highlighted: (i) an increased level in xyloglucan endotransglucosylase/hydrolase (XTH) and expansin proteins, associated with an increase in the degree of rhamnogalacturonan I branching that maintains cell wall plasticity and (ii) an increased cell wall thickening by reinforcement of the secondary wall with hemicellulose and lignin deposition. Taken together, these results show the need to undertake large-scale analyses, using multidisciplinary approaches, to unravel the consequences of stress on the cell wall. This will help identify the key components that could be targeted to improve biomass production under stress conditions. PMID:27135320

An analysis of static loading results on slotted ring samples to allow for further investigation of stress corrosion cracking

Energy Technology Data Exchange (ETDEWEB)

Metzler, J.; Ferrier, G.A.; Farahani, M.; Chan, P.K.; Corcoran, E.C., E-mail: Joseph.Metzler@rmc.ca [Royal Military College of Canada, Kingston, ON (Canada)

2014-07-01

Stress corrosion cracking can cause failures of CANDU Zircaloy-4 fuel sheathing. A series of static loading tests were performed on slotted ring samples in support of ongoing efforts to analyze the effects of iodine concentration, temperature, and stress levels on the corrosion of Zircaloy-4. The corrosive degradation of Zircaloy-4 was evaluated using deflection measurements. A regression analysis determined that iodine concentration and temperature have had a linear effect on deflection results thus far, while the stress level has not. (author)

The Impairing Role of Stress on Autobiographical Memory Reconsolidation

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Zeinab Azimi

2012-10-01

Full Text Available Background: Despite some studies indicating improving role of stress on memory consolidation, very few animal and human studies show that stress impairs reconsolidation of memories. This study aimed to determine the effect of stress on autobiographical memory reconsolidation.Materials and Methods: The present study was done with an experimental method (Solomon Four-Group design. The statistical society of this study was all undergraduate female students in 2009-2010 academic year at Tabriz University. Forty students were selected using random cluster sampling, and we ensure about their physical and mental health by GHQ-28 and interview. Tools for this study were cueing autobiographical memory test, SECPT (for raising blood pressure and stress induction, autobiographical memory test, PANAS and general health questionnaire (GHQ-28. MANOVA was used for data analysis by SPSS-17.Results: The results show that stress after activation of memory impairs memory for neutral events (p0.05. None of stress and memory activation alone had effect on memory performance (p>0.05.Conclusion: These findings indicate that stress impairs autobiographical memory reconsolidation, which is opposite to its effects on memory consolidation, so it supports the view that consolidation and reconsolidation are separate process.

Canadian dental students' perceptions of stress.

Science.gov (United States)

Muirhead, Vanessa; Locker, David

2007-05-01

In this paper, we report the results of a survey on dental student stress carried out in April 2005. A questionnaire was used to collect data from 171 students (62% response rate). Identified stressors were academic, clinic-related, social and financial. "Examination and grades" produced the most academic stress, and inconsistent feedback from instructors created the most clinic-related stress. Students found that having a dual role--wife or husband and dental student--was the most burdensome social stressor. Approximately 60% of students reported marital problems and stress associated with "relations with members of the opposite sex." Survey results showed that students who expected a high graduating debt had higher total and academic stress scores. Total stress was not related to age, gender or marital status. Students living with parents during term time had significantly higher total stress scores than students living in other arrangements. Students residing with parents also had significantly higher debts on entry to dental school. Students with more predental education had (non-significantly) lower stress scores but also had higher student debts. Undergraduate subject major (biological science or non-science) had no bearing on reported stress. This study highlights the negative effects of student debt, the necessity for staff training and the need for further studies exploring relations among stress, psychological well-being and academic performance.

Circulating biologically active oxidized phospholipids show on-going and increased oxidative stress in older male mice

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Jinbo Liu

2013-01-01

Significance: Oxidatively modified phospholipids are increased in the circulation during common, mild oxidant stresses of aging, or in male compared to female animals. Turnover of these biologically active phospholipids by rapid transport into liver and kidney is unchanged, so circulating levels reflect continuously increased production.

Genome-wide analysis identifies chickpea (Cicer arietinum) heat stress transcription factors (Hsfs) responsive to heat stress at the pod development stage.

Science.gov (United States)

Chidambaranathan, Parameswaran; Jagannadham, Prasanth Tej Kumar; Satheesh, Viswanathan; Kohli, Deshika; Basavarajappa, Santosh Halasabala; Chellapilla, Bharadwaj; Kumar, Jitendra; Jain, Pradeep Kumar; Srinivasan, R

2018-05-01

The heat stress transcription factors (Hsfs) play a prominent role in thermotolerance and eliciting the heat stress response in plants. Identification and expression analysis of Hsfs gene family members in chickpea would provide valuable information on heat stress responsive Hsfs. A genome-wide analysis of Hsfs gene family resulted in the identification of 22 Hsf genes in chickpea in both desi and kabuli genome. Phylogenetic analysis distinctly separated 12 A, 9 B, and 1 C class Hsfs, respectively. An analysis of cis-regulatory elements in the upstream region of the genes identified many stress responsive elements such as heat stress elements (HSE), abscisic acid responsive element (ABRE) etc. In silico expression analysis showed nine and three Hsfs were also expressed in drought and salinity stresses, respectively. Q-PCR expression analysis of Hsfs under heat stress at pod development and at 15 days old seedling stage showed that CarHsfA2, A6, and B2 were significantly upregulated in both the stages of crop growth and other four Hsfs (CarHsfA2, A6a, A6c, B2a) showed early transcriptional upregulation for heat stress at seedling stage of chickpea. These subclasses of Hsfs identified in this study can be further evaluated as candidate genes in the characterization of heat stress response in chickpea.

Thermal stress effects in intermetallic matrix composites

Science.gov (United States)

Wright, P. K.; Sensmeier, M. D.; Kupperman, D. S.; Wadley, H. N. G.

1993-01-01

Intermetallic matrix composites develop residual stresses from the large thermal expansion mismatch (delta-alpha) between the fibers and matrix. This work was undertaken to: establish improved techniques to measure these thermal stresses in IMC's; determine residual stresses in a variety of IMC systems by experiments and modeling; and, determine the effect of residual stresses on selected mechanical properties of an IMC. X ray diffraction (XRD), neutron diffraction (ND), synchrotron XRD (SXRD), and ultrasonics (US) techniques for measuring thermal stresses in IMC were examined and ND was selected as the most promising technique. ND was demonstrated on a variety of IMC systems encompassing Ti- and Ni-base matrices, SiC, W, and Al2O3 fibers, and different fiber fractions (Vf). Experimental results on these systems agreed with predictions of a concentric cylinder model. In SiC/Ti-base systems, little yielding was found and stresses were controlled primarily by delta-alpha and Vf. In Ni-base matrix systems, yield strength of the matrix and Vf controlled stress levels. The longitudinal residual stresses in SCS-6/Ti-24Al-llNb composite were modified by thermomechanical processing. Increasing residual stress decreased ultimate tensile strength in agreement with model predictions. Fiber pushout strength showed an unexpected inverse correlation with residual stress. In-plane shear yield strength showed no dependence on residual stress. Higher levels of residual tension led to higher fatigue crack growth rates, as suggested by matrix mean stress effects.

Stress effect on conception rate in Nellore cows submmited to fixed time artificial insemination. Preliminary results

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Fábio Luis Nogueira Natal

2013-12-01

Full Text Available In beef cattle, fixed time artificial insemination (FTAI provides a method to inseminate large numbers of females in a specific time, which result in economical gains due, among others, to a more uniform calf crop. However, FTAI requires frequent manipulation of animals in order to inject hormones and for clinical examination. Consequently, animals seemed stressed in less or higher extent at the time of insemination. This can be a problem because it has been demonstrated that application of an acute stress treatment (electric shock, confinement, restraint and rotation twice a day during the follicular phase of the oestrous cycle prevents the pre-ovulatory LH surge. This study aimed to evaluate if FTAI efficiency of Nellore cows is affected by the degree of stress observed at time of AI. Nellore cows (n=92 were treated (Day 0 with a progesterone intravaginal devise (Primer®, Tecnopec, São Paulo, Brazil containing 1 g of progesterone and injected with estradiol benzoate (2mg EB, Estrogin, AUSA, Brazil. Primer was removed on Day 8 (08:00 AM and administered one injection of cloprostenol (125 mcg, Prolise®, Tecnopec, São Paulo, Brazil. Twenty-four hours later, cows received 2 mg EB and insemination (semen from one sire was done on the afternoon (14:00 to 16:00 PM of day 10. At time of FTAI, the stress condition was classified as 1 (low, 2 (moderate or 3 (high according the reactivity of cows to enter in the squeeze chute and apparent nervous behavior. Pregnancy status was evaluated by transrectal ultrasound on day 40 after FTAI. Data were analyzed by Chi-square test. Cows with moderate or high degree of stress had lower conception rate than low stressed cows (P<0.01. These results suggest that cow temperament must be considered in the planning of FTAI programs. Studies are in progress in order to measure hormonal parameters (cortisol and Alpha amylase that better reflects the “fight-or-flight” response to immediate stressors in order to

Linear elastic obstacles: analysis of experimental results in the case of stress dependent pre-exponentials

International Nuclear Information System (INIS)

Surek, T.; Kuon, L.G.; Luton, M.J.; Jones, J.J.

1975-01-01

For the case of linear elastic obstacles, the analysis of experimental plastic flow data is shown to have a particularly simple form when the pre-exponential factor is a single-valued function of the modulus-reduced stress. The analysis permits the separation of the stress and temperature dependence of the strain rate into those of the pre-exponential factor and the activation free energy. As a consequence, the true values of the activation enthalpy, volume and entropy also are obtained. The approach is applied to four sets of experimental data, including Zr, and the results for the pre-exponential term are examined for self-consistency in view of the assumed functional dependence

Stress at work: development of the Stress Perception Questionnaire of Rome (SPQR), an ad hoc questionnaire for multidimensional assessment of work related stress.

Science.gov (United States)

Cinti, M E; Cannavò, M; Fioravanti, M

2017-01-01

Stress is an emotional condition, mostly experienced as negative, initially identified and defined by Selye in the mid-thirties of the last Century. Since the first definition, stress concerns the adaptation pro- cess mostly related to environmental changes. An application of stress focuses on the evaluation of its interference on work conditions, and the scientific evidence on work related stress is very ample and rich. We are proposing a new ad hoc questionnaire for the multidimensional assessment of work related stress, called Stress Perception Question- naire of Rome (SPQR) composed of 50 items. The development of this questionnaire is based on a multi-step process: a) Identification of all the relevant topics to work related stress and areas in the scientific evidence and their transformation on specific contents of 60 tentative items; b) Exploratory factor analysis aimed to identify the best items (50) which could guarantee the maximum convergence on single scales (8), and the minimum redundancy between scales; c) Validation of the 8 scales' structure by a confirmatory factor analysis (fully achieved); d) Factor analysis for a second level factor resulting in a single factor identified as the questionnaire total score (Stress Score); d) Reliability analysis of the questionnaire total score and the single scale scores (at optimum level); e) Validation by external criteria of work related stress identified in the presence of personal violence episodes experienced by a group of health workers with different professional profiles and from two different hospitals in Rome. Our results show that the SPQR is a useful and sensitive tool for assessing the presence of emotional stress related problems identifiable in a work environment. The advantage of this questionnaire is that it allows for a multidimensional description of the different components of this problematic area besides its ability to quantify the overall stress level of those who have been administered

A Comparative Study of Stressful Life Events and Stress Coping Strategies in Coronary Heart Disease Patients and Non-Patients

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A. Heidari Pahlavian

2010-10-01

Full Text Available Introduction & Objective: Etiological researches suggest that biopsychosocial dimensions are responsible for coronary heart disease (CHD. The main goal of the present research was to compare stressful life events and stress coping strategies in coronary heart patients (Acute Myocardial Infarction and non-patients. Materials & Methods: In this cross sectional research 102 patients (all males suffering from acute myocardial infarction and 162 non-patient individuals after matching were studied and compared with regard to psychosocial life events and stress coping strategies through coping response inventory (Moos, 1993 , scaling of life Events (paykel , 1971 and researcher made questionnaire. Results: The result established that myocardial infarction patients experienced more stress than the control group during one year before heart- attack and they used more inadequate stress coping strategies comparing with the control individuals. Conclusion: This study showed that stress and inadequate coping strategies are important variables for the development of coronary heart diseases. (Sci J Hamadan Univ Med Sci 2010;17(3:33-38

Elaboration of the Environmental Stress Hypothesis – Results from a population-based 6-year follow-up

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Matthias Wagner

2016-12-01

Full Text Available The aim of this paper was to contribute to the elaboration of the Environmental Stress Hypothesis framework by testing eight hypotheses addressing the direct impact of gross motor coordination problems in elementary-school on selected physical, behavioral and psychosocial outcomes in adolescence. Results are based on a longitudinal sample of 940 participants who were (i recruited as part of a population-based representative survey on health, physical fitness and physical activity in childhood and adolescence, (ii assessed twice within 6 years, between the ages of 6 and 10 years old as well as between the ages of 12 and 16 years old (Response Rate: 55.9% and (iii classified as having gross motor coordination problems (N = 115 or having no gross motor coordination problems (N = 825 at baseline.Motor tests from the Körperkoordinationstest, measures of weight and height, a validated physical activity questionnaire as well as the Strength and Difficulties Questionnaire were conducted. Data were analyzed by use of binary logistic regressions. Results indicated that elementary-school children with gross motor coordination problems show a higher risk of persistent gross motor coordination problems (OR = 7.99, p < .001, avoiding organized physical activities (OR = 1.53, p < .05, an elevated body mass (OR = 1.78, p < .05, bonding with sedentary peers (OR = 1.84, p < .01 as well as emotional (OR = 1.73, p < .05 and conduct (OR = 1.79, p < .05 problems in adolescence in comparison to elementary-school children without gross motor coordination problems. However, elementary-school children with gross motor coordination problems did not show a significantly higher risk of peer problems (OR = 1.35, p = .164 or diminished prosocial behavior (OR = 1.90, p = .168 in adolescence, respectively in comparison to elementary-school children without gross motor coordination problems. This study is the first to provide population-based longitudinal data ranging from

Effect of yoga on academic performance in relation to stress

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Kauts Amit

2009-01-01

Full Text Available Background: Academic performance is concerned with the quantity and quality of learning attained in a subject or group of subjects after a long period of instruction. Excessive stress hampers students′ performance. Improvement in academic performance and alertness has been reported in several yogic studies. Aims and Objectives: The main objective of the study was to assess the effect of yoga on academic performance in relation to stress. Materials and Methods: The study started with 800 adolescent students; 159 high-stress students and 142 low-stress students were selected on the basis of scores obtained through Stress Battery. Experimental group and control group were given pre test in three subjects, i.e., Mathematics, Science, and Social Studies. A yoga module consisting of yoga asanas, pranayama, meditation, and a value orientation program was administered on experimental group for 7 weeks. The experimental and control groups were post-tested for their performance on the three subjects mentioned above. Results: The results show that the students, who practiced yoga performed better in academics. The study further shows that low-stress students performed better than high-stress students, meaning thereby that stress affects the students′ performance.

Background Stress Inventory: Developing a Measure of Understudied Stress.

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Terrill, Alexandra L; Gjerde, Jill M; Garofalo, John P

2015-10-01

Background stress is an understudied source of stress that involves both ambient stress and daily hassles upon which new stressors are superimposed. To date, an accurate measure of the background stress construct has not been available. We developed the Background Stress Inventory, a 25-item self-report measure that asks respondents to indicate how distressed they have felt over the past month and the majority of the past year across five domains: financial, occupation, environment, health and social. Seven hundred seventy-two participants completed the paper-and-pencil measure; the sample was randomly split into two separate subsamples for analyses. Exploratory factor analysis suggested five factors corresponding to these domains, and confirmatory factor analysis showed acceptable global fit (X(2)(255) = 456.47, comparative fit index = 0.94, root mean square error of approximation = 0.045). Cronbach's alpha (0.89) indicated good internal reliability. Construct validity analyses showed significant positive relationships with measures of perceived stressfulness (r = 0.62) and daily hassles (0.41), p's < 0.01. Depressive symptoms (0.62) and basal blood pressure (0.21) were both significantly associated with background stress, p's < 0.01. The importance of the proposed measure is reflected in the limited research base on the impact of background stress. Systematic investigation of this measure will provide insight into this understudied form of chronic stress and its potential influence on both psychological and physical endpoints. Copyright © 2013 John Wiley & Sons, Ltd.

Stress vulnerability and the effects of moderate daily stress on sleep polysomnography and subjective sleepiness.

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Petersen, Helena; Kecklund, Göran; D'Onofrio, Paolo; Nilsson, Jens; Åkerstedt, Torbjörn

2013-02-01

The purpose of this study was to investigate if and how sleep physiology is affected by naturally occurring high work stress and identify individual differences in the response of sleep to stress. Probable upcoming stress levels were estimated through weekly web questionnaire ratings. Based on the modified FIRST-scale (Ford insomnia response to stress) participants were grouped into high (n = 9) or low (n = 19) sensitivity to stress related sleep disturbances (Drake et al., 2004). Sleep was recorded in 28 teachers with polysomnography, sleep diaries and actigraphs during one high stress and one low stress condition in the participants home. EEG showed a decrease in sleep efficiency during the high stress condition. Significant interactions between group and condition were seen for REM sleep, arousals and stage transitions. The sensitive group had an increase in arousals and stage transitions during the high stress condition and a decrease in REM, whereas the opposite was seen in the resilient group. Diary ratings during the high stress condition showed higher bedtime stress and lower ratings on the awakening index (insufficient sleep and difficulties awakening). Ratings also showed lower cognitive function and preoccupation with work thoughts in the evening. KSS ratings of sleepiness increased during stress for the sensitive group. Saliva samples of cortisol showed no effect of stress. It was concluded that moderate daily stress is associated with a moderate negative effect on sleep sleep efficiency and fragmentation. A slightly stronger effect was seen in the sensitive group. © 2012 European Sleep Research Society.

Transcriptome Analysis of Sunflower Genotypes with Contrasting Oxidative Stress Tolerance Reveals Individual- and Combined- Biotic and Abiotic Stress Tolerance Mechanisms.

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Vemanna S Ramu

Full Text Available In nature plants are often simultaneously challenged by different biotic and abiotic stresses. Although the mechanisms underlying plant responses against single stress have been studied considerably, plant tolerance mechanisms under combined stress is not understood. Also, the mechanism used to combat independently and sequentially occurring many number of biotic and abiotic stresses has also not systematically studied. From this context, in this study, we attempted to explore the shared response of sunflower plants to many independent stresses by using meta-analysis of publically available transcriptome data and transcript profiling by quantitative PCR. Further, we have also analyzed the possible role of the genes so identified in contributing to combined stress tolerance. Meta-analysis of transcriptomic data from many abiotic and biotic stresses indicated the common representation of oxidative stress responsive genes. Further, menadione-mediated oxidative stress in sunflower seedlings showed similar pattern of changes in the oxidative stress related genes. Based on this a large scale screening of 55 sunflower genotypes was performed under menadione stress and those contrasting in oxidative stress tolerance were identified. Further to confirm the role of genes identified in individual and combined stress tolerance the contrasting genotypes were individually and simultaneously challenged with few abiotic and biotic stresses. The tolerant hybrid showed reduced levels of stress damage both under combined stress and few independent stresses. Transcript profiling of the genes identified from meta-analysis in the tolerant hybrid also indicated that the selected genes were up-regulated under individual and combined stresses. Our results indicate that menadione-based screening can identify genotypes not only tolerant to multiple number of individual biotic and abiotic stresses, but also the combined stresses.

Non-Destructive Evaluation Method Based On Dynamic Invariant Stress Resultants

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Zhang Junchi

2015-01-01

Full Text Available Most of the vibration based damage detection methods are based on changes in frequencies, mode shapes, mode shape curvature, and flexibilities. These methods are limited and typically can only detect the presence and location of damage. Current methods seldom can identify the exact severity of damage to structures. This paper will present research in the development of a new non-destructive evaluation method to identify the existence, location, and severity of damage for structural systems. The method utilizes the concept of invariant stress resultants (ISR. The basic concept of ISR is that at any given cross section the resultant internal force distribution in a structural member is not affected by the inflicted damage. The method utilizes dynamic analysis of the structure to simulate direct measurements of acceleration, velocity and displacement simultaneously. The proposed dynamic ISR method is developed and utilized to detect the damage of corresponding changes in mass, damping and stiffness. The objectives of this research are to develop the basic theory of the dynamic ISR method, apply it to the specific types of structures, and verify the accuracy of the developed theory. Numerical results that demonstrate the application of the method will reflect the advanced sensitivity and accuracy in characterizing multiple damage locations.

Correlation Between Fracture Network Properties and Stress Variability in Geological Media

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Lei, Qinghua; Gao, Ke

2018-05-01

We quantitatively investigate the stress variability in fractured geological media under tectonic stresses. The fracture systems studied include synthetic fracture networks following power law length scaling and natural fracture patterns based on outcrop mapping. The stress field is derived from a finite-discrete element model, and its variability is analyzed using a set of mathematical formulations that honor the tensorial nature of stress data. We show that local stress perturbation, quantified by the Euclidean distance of a local stress tensor to the mean stress tensor, has a positive, linear correlation with local fracture intensity, defined as the total fracture length per unit area within a local sampling window. We also evaluate the stress dispersion of the entire stress field using the effective variance, that is, a scalar-valued measure of the overall stress variability. The results show that a well-connected fracture system under a critically stressed state exhibits strong local and global stress variabilities.

Stress field determination in an alloy 600 stress corrosion crack specimen

International Nuclear Information System (INIS)

Rassineux, B.; Labbe, T.

1995-05-01

In the context of EDF studies on stress corrosion cracking rates in the Alloy 600 steam generators tubes, we studied the influence of strain hardened surface layers on the different stages of cracking for a tensile smooth specimen (TLT). The stress field was notably assessed to try and explain the slow/rapid-propagation change observed beyond the strain hardened layers. The main difficulty is to simulate in a finite element model the inner and outer surfaces of these strain hardened layers, produced by the final manufacturing stages of SG tubes which have not been heat treated. In the model, the strain hardening is introduced by simulating a multi-layer material. Residual stresses are simulated by an equivalent fictitious thermomechanical calculation, realigned with respect to X-ray measurements. The strain hardening introduction method was validated by an analytical calculation giving identical results. Stress field evolution induced by specimen tensile loading were studied using an elastoplastic 2D finite element calculations performed with the Aster Code. The stress profile obtained after load at 660 MPa shows no stress discontinuity at the boundary between the strain hardened layer and the rest of the tube. So we propose that a complementary calculation be performed, taking into account the multi-cracked state of the strain hardened zones by means of a damage variable. In fact, this state could induce stress redistribution in the un-cracked area, which would perhaps provide an explanation of the crack-ground rate change beyond the strain hardened zone. The calculations also evidence the harmful effects of plastic strains on a strain hardened layer due to the initial state of the tube (not heat-treated), to grit blasting or to shot peening. The initial compressive stress condition of this surface layer becomes, after plastic strain, a tensile stress condition. These results are confirmed by laboratory test. (author). 10 refs., 18 figs., 9 tabs., 2 appends

Stress views in the radiography of scapholunate instability

International Nuclear Information System (INIS)

Ozcelik, Abdurrahman; Guenal, Izge; Koese, Nusret

2005-01-01

Aim: On the suspected carpal instabilities stress views are recommended but not often used. The present study evaluates the reliability of the dorsal and volar stress radiographs on patients with posttraumatic wrist pain. Patients and methods: Stress radiographs of the wrists were examined in 22 patients with chronic wrist pain and the results were compared with scaphoid shift test and standard and positional views. The stress examination consists of applying to the wrist dorsal and volar stresses on the hand. Results: Static scapholunate instability was diagnosed in 4 patients in whom 3 of them had positive scaphoid shift test sign as well. There were, however, 18 patients with dynamic scapholunate instability in whom the standard films were normal but dorsal stress radiography showed gap greater than 3 mm between the scaphoid and lunate. Conclusion: Stress tests may provide considerable information in the evaluation of a patient who has a painful wrist in whom routine and special views do not demonstrate scapholunate dissociation

NDE of stresses in thick-walled components by ultrasonic methods

International Nuclear Information System (INIS)

Goebbels, K.; Pitsch, H.; Schneider, E.; Nowack, H.

1985-01-01

The possibilty of measuring stresses - especially residual stresses - by ultrasonic methods has been presented at the 4th and 5th International Conference on NDE in Nuclear Industry. This contribution now presents results of several applications to thick walled components such as turbines and generators for power plants. The measurement technique using linearly polarized shear waves allows one to characterize the homogeneitry of the residual stress situation along and around cylindrically shaped components. Some important results show that the stress distribution integrated over the cross section of the component has not followed in any case the simple relations derived by stress analysts. Conclusions referring to the stress situation inside the components are discussed

Analysis of primary teacher stress' sources

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Katja Depolli Steiner

2011-12-01

Full Text Available Teachers are subject to many different work stressors. This study focused on differences in intensity and frequency of potential stressors facing primary schoolteachers and set the goal to identify the most important sources of teacher stress in primary school. The study included 242 primary schoolteachers from different parts of Slovenia. We used Stress Inventory that is designed for identification of intensity and frequency of 49 situations that can play the role of teachers' work stressors. Findings showed that the major sources of stress facing teachers are factors related to work overload, factors stemming from pupils' behaviour and motivation and factors related to school system. Results also showed some small differences in perception of stressors in different groups of teachers (by gender and by teaching level.

Environmental stresses can alleviate the average deleterious effect of mutations

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Leibler Stanislas

2003-05-01

Full Text Available Abstract Background Fundamental questions in evolutionary genetics, including the possible advantage of sexual reproduction, depend critically on the effects of deleterious mutations on fitness. Limited existing experimental evidence suggests that, on average, such effects tend to be aggravated under environmental stresses, consistent with the perception that stress diminishes the organism's ability to tolerate deleterious mutations. Here, we ask whether there are also stresses with the opposite influence, under which the organism becomes more tolerant to mutations. Results We developed a technique, based on bioluminescence, which allows accurate automated measurements of bacterial growth rates at very low cell densities. Using this system, we measured growth rates of Escherichia coli mutants under a diverse set of environmental stresses. In contrast to the perception that stress always reduces the organism's ability to tolerate mutations, our measurements identified stresses that do the opposite – that is, despite decreasing wild-type growth, they alleviate, on average, the effect of deleterious mutations. Conclusions Our results show a qualitative difference between various environmental stresses ranging from alleviation to aggravation of the average effect of mutations. We further show how the existence of stresses that are biased towards alleviation of the effects of mutations may imply the existence of average epistatic interactions between mutations. The results thus offer a connection between the two main factors controlling the effects of deleterious mutations: environmental conditions and epistatic interactions.

[Nearby nature as a moderator of stress during childhood].

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Corraliza, José Antonio; Collado, Silvia

2011-04-01

The aim of this investigation is to study the relation between the amount of nature existing in children's daily environments and the way children deal with stressful events. Every day, children are exposed to situations that cause stress. Taking into account previous studies, it is thought that the greener the place where children spend their time, the better they cope with adversities. Thus, when comparing the stress level of children who are exposed to the same amount of adverse situations, the children who have more frequent daily contact with nature will show less stress than those who do not spend time in nature. This effect from nearby nature is called a buffering effect. The present study provides empirical evidence of the buffering effect caused by the existence of Nature in the residential and the school environment. Therefore, our results show that children who have more access to nature increase their resilience, showing a lower stress level than children whose contact with nature is less frequent.

Efficacy of a short-term yoga-based lifestyle intervention in reducing stress and inflammation: preliminary results.

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Yadav, Raj Kumar; Magan, Dipti; Mehta, Nalin; Sharma, Ratna; Mahapatra, Sushil Chandra

2012-07-01

Previously it was shown that a brief yoga-based lifestyle intervention was efficacious in reducing oxidative stress and risk of chronic diseases even in a short duration. The objective of this study was to assess the efficacy of this intervention in reducing stress and inflammation in patients with chronic inflammatory diseases. This study reports preliminary results from a nonrandomized prospective ongoing study with pre-post design. The study was conducted at the Integral Health Clinic, an outpatient facility conducting these yoga-based lifestyle intervention programs for prevention and management of chronic diseases. Patients with chronic inflammatory diseases and overweight/obese subjects were included while physically challenged, and those on other interventions were excluded from the study. A pretested intervention program included asanas (postures), pranayama (breathing exercises), stress management, group discussions, lectures, and individualized advice. There was a reduction in stress (plasma cortisol and β-endorphin) and inflammation (interleukin [IL]-6 and tumor necrosis factor [TNF]-α) at day 0 versus day 10. Eighty-six (86) patients (44 female, 42 male, 40.07 ± 13.91 years) attended this program. Overall, the mean level of cortisol decreased from baseline to day 10 (149.95 ± 46.07, 129.07 ± 33.30 ng/mL; p=0.001) while β-endorphins increased from baseline to day 10 (3.53 ± 0.88, 4.06 ± 0.79 ng/mL; p=0.024). Also, there was reduction from baseline to day 10 in mean levels of IL-6 (2.16 ± 0.42, 1.94 ± 0.10 pg/mL, p=0.036) and TNF-α (2.85 ± 0.59, 1.95 ± 0.32 pg/mL, p=0.002). This brief yoga-based lifestyle intervention reduced the markers of stress and inflammation as early as 10 days in patients with chronic diseases; however, complete results of this study will confirm whether this program has utility as complementary and alternative therapy.

Numerical simulation of transformation-induced microscopic residual stress in ferrite-martensite lamellar steel

International Nuclear Information System (INIS)

Mikami, Y; Inao, A; Mochizuki, M; Toyoda, M

2009-01-01

The effect of transformation-induced microscopic residual stress on fatigue crack propagation behavior of ferrite-martensite lamellar steel was discussed. Fatigue tests of prestrained and non-prestrained specimens were performed. Inflections and branches at ferrite-martensite boundaries were observed in the non-prestrained specimens. On the other hand, less inflections and branches were found in the prestrained specimens. The experimental results showed that the transformation induced microscopic residual stress has influence on the fatigue crack propagation behavior. To estimate the microscopic residual, a numerical simulation method for the calculation of microscopic residual stress stress induced by martensitic transformation was performed. The simulation showed that compressive residual stress was generated in martensite layer, and the result agree with the experimental result that inflections and branches were observed at ferrite-martensite boundaries.

Thermographic Analysis of Stress Distribution in Welded Joints

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Domazet Ž.

2010-06-01

Full Text Available The fatigue life prediction of welded joints based on S-N curves in conjunction with nominal stresses generally is not reliable. Stress distribution in welded area affected by geometrical inhomogeneity, irregular welded surface and weld toe radius is quite complex, so the local (structural stress concept is accepted in recent papers. The aim of this paper is to determine the stress distribution in plate type aluminum welded joints, to analyze the reliability of TSA (Thermal Stress Analysis in this kind of investigations, and to obtain numerical values for stress concentration factors for practical use. Stress distribution in aluminum butt and fillet welded joints is determined by using the three different methods: strain gauges measurement, thermal stress analysis and FEM. Obtained results show good agreement - the TSA mutually confirmed the FEM model and stresses measured by strain gauges. According to obtained results, it may be stated that TSA, as a relatively new measurement technique may in the future become a standard tool for the experimental investigation of stress concentration and fatigue in welded joints that can help to develop more accurate numerical tools for fatigue life prediction.

Thermographic Analysis of Stress Distribution in Welded Joints

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Piršić, T.; Krstulović Opara, L.; Domazet, Ž.

2010-06-01

The fatigue life prediction of welded joints based on S-N curves in conjunction with nominal stresses generally is not reliable. Stress distribution in welded area affected by geometrical inhomogeneity, irregular welded surface and weld toe radius is quite complex, so the local (structural) stress concept is accepted in recent papers. The aim of this paper is to determine the stress distribution in plate type aluminum welded joints, to analyze the reliability of TSA (Thermal Stress Analysis) in this kind of investigations, and to obtain numerical values for stress concentration factors for practical use. Stress distribution in aluminum butt and fillet welded joints is determined by using the three different methods: strain gauges measurement, thermal stress analysis and FEM. Obtained results show good agreement - the TSA mutually confirmed the FEM model and stresses measured by strain gauges. According to obtained results, it may be stated that TSA, as a relatively new measurement technique may in the future become a standard tool for the experimental investigation of stress concentration and fatigue in welded joints that can help to develop more accurate numerical tools for fatigue life prediction.

Slow Replication Fork Velocity of Homologous Recombination-Defective Cells Results from Endogenous Oxidative Stress

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Magdalou, Indiana; Machon, Christelle; Dardillac, Elodie; Técher, Hervé; Guitton, Jérôme; Debatisse, Michelle; Lopez, Bernard S.

2016-01-01

Replications forks are routinely hindered by different endogenous stresses. Because homologous recombination plays a pivotal role in the reactivation of arrested replication forks, defects in homologous recombination reveal the initial endogenous stress(es). Homologous recombination-defective cells consistently exhibit a spontaneously reduced replication speed, leading to mitotic extra centrosomes. Here, we identify oxidative stress as a major endogenous source of replication speed deceleration in homologous recombination-defective cells. The treatment of homologous recombination-defective cells with the antioxidant N-acetyl-cysteine or the maintenance of the cells at low O2 levels (3%) rescues both the replication fork speed, as monitored by single-molecule analysis (molecular combing), and the associated mitotic extra centrosome frequency. Reciprocally, the exposure of wild-type cells to H2O2 reduces the replication fork speed and generates mitotic extra centrosomes. Supplying deoxynucleotide precursors to H2O2-exposed cells rescued the replication speed. Remarkably, treatment with N-acetyl-cysteine strongly expanded the nucleotide pool, accounting for the replication speed rescue. Remarkably, homologous recombination-defective cells exhibit a high level of endogenous reactive oxygen species. Consistently, homologous recombination-defective cells accumulate spontaneous γH2AX or XRCC1 foci that are abolished by treatment with N-acetyl-cysteine or maintenance at 3% O2. Finally, oxidative stress stimulated homologous recombination, which is suppressed by supplying deoxynucleotide precursors. Therefore, the cellular redox status strongly impacts genome duplication and transmission. Oxidative stress should generate replication stress through different mechanisms, including DNA damage and nucleotide pool imbalance. These data highlight the intricacy of endogenous replication and oxidative stresses, which are both evoked during tumorigenesis and senescence initiation

Slow Replication Fork Velocity of Homologous Recombination-Defective Cells Results from Endogenous Oxidative Stress.

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Therese Wilhelm

2016-05-01

Full Text Available Replications forks are routinely hindered by different endogenous stresses. Because homologous recombination plays a pivotal role in the reactivation of arrested replication forks, defects in homologous recombination reveal the initial endogenous stress(es. Homologous recombination-defective cells consistently exhibit a spontaneously reduced replication speed, leading to mitotic extra centrosomes. Here, we identify oxidative stress as a major endogenous source of replication speed deceleration in homologous recombination-defective cells. The treatment of homologous recombination-defective cells with the antioxidant N-acetyl-cysteine or the maintenance of the cells at low O2 levels (3% rescues both the replication fork speed, as monitored by single-molecule analysis (molecular combing, and the associated mitotic extra centrosome frequency. Reciprocally, the exposure of wild-type cells to H2O2 reduces the replication fork speed and generates mitotic extra centrosomes. Supplying deoxynucleotide precursors to H2O2-exposed cells rescued the replication speed. Remarkably, treatment with N-acetyl-cysteine strongly expanded the nucleotide pool, accounting for the replication speed rescue. Remarkably, homologous recombination-defective cells exhibit a high level of endogenous reactive oxygen species. Consistently, homologous recombination-defective cells accumulate spontaneous γH2AX or XRCC1 foci that are abolished by treatment with N-acetyl-cysteine or maintenance at 3% O2. Finally, oxidative stress stimulated homologous recombination, which is suppressed by supplying deoxynucleotide precursors. Therefore, the cellular redox status strongly impacts genome duplication and transmission. Oxidative stress should generate replication stress through different mechanisms, including DNA damage and nucleotide pool imbalance. These data highlight the intricacy of endogenous replication and oxidative stresses, which are both evoked during tumorigenesis and

Slow Replication Fork Velocity of Homologous Recombination-Defective Cells Results from Endogenous Oxidative Stress.

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Wilhelm, Therese; Ragu, Sandrine; Magdalou, Indiana; Machon, Christelle; Dardillac, Elodie; Técher, Hervé; Guitton, Jérôme; Debatisse, Michelle; Lopez, Bernard S

2016-05-01

Replications forks are routinely hindered by different endogenous stresses. Because homologous recombination plays a pivotal role in the reactivation of arrested replication forks, defects in homologous recombination reveal the initial endogenous stress(es). Homologous recombination-defective cells consistently exhibit a spontaneously reduced replication speed, leading to mitotic extra centrosomes. Here, we identify oxidative stress as a major endogenous source of replication speed deceleration in homologous recombination-defective cells. The treatment of homologous recombination-defective cells with the antioxidant N-acetyl-cysteine or the maintenance of the cells at low O2 levels (3%) rescues both the replication fork speed, as monitored by single-molecule analysis (molecular combing), and the associated mitotic extra centrosome frequency. Reciprocally, the exposure of wild-type cells to H2O2 reduces the replication fork speed and generates mitotic extra centrosomes. Supplying deoxynucleotide precursors to H2O2-exposed cells rescued the replication speed. Remarkably, treatment with N-acetyl-cysteine strongly expanded the nucleotide pool, accounting for the replication speed rescue. Remarkably, homologous recombination-defective cells exhibit a high level of endogenous reactive oxygen species. Consistently, homologous recombination-defective cells accumulate spontaneous γH2AX or XRCC1 foci that are abolished by treatment with N-acetyl-cysteine or maintenance at 3% O2. Finally, oxidative stress stimulated homologous recombination, which is suppressed by supplying deoxynucleotide precursors. Therefore, the cellular redox status strongly impacts genome duplication and transmission. Oxidative stress should generate replication stress through different mechanisms, including DNA damage and nucleotide pool imbalance. These data highlight the intricacy of endogenous replication and oxidative stresses, which are both evoked during tumorigenesis and senescence initiation

Time series analysis of blood oxidative stress value in irradiated rats

International Nuclear Information System (INIS)

Kaneko, Takashi; Goto, Jun; Nomiya, Takuma; Nemoto, Kenji

2011-01-01

Indirect effect of ionizing-radiation causes free radicals and reactive oxgen species (ROS). These ROS interact with DNA or other organella, and cause oxidative damage to nucleic acids, membrane lipoprotein, mitchondria and others. The purpose of this study is to evaluate oxidative damage by irradiation using d-ROMs test. Electron beam was irradiated to the thigh of Wistar strain female rats, and reactive oxygen metabolites in the blood from these rats were measured and analysed. From the results, 2 Gy group shows significantly higher oxidative stress level than those of 0 Gy group especially in day 3 after irradiation. This oxidative stress definitely seemed to be caused by exposure to ionizing-radiation. In contrast, the group of 30 Gy-irradiation showed no significant increase of oxidative stress level. It was thought that oxidative stress caused by radiation was neutralized by expression of stress-induced antioxidant enzymes. These data resulted that d-ROMs test is useful for measuring oxidative stress levels of irradiated mammalian animals. (author)

Residual stresses associated with welds in austenitic steel

International Nuclear Information System (INIS)

Fidler, R.

1978-01-01

Two exploratory welds have been made with AISI 316 austenitic steel and Armex GT electrodes by the manual metal-arc process, and residual stress measurements made in the as-welded condition and after various periods of stress relief. The results show that substantial stress relief occurs at temperatures of 850 0 and 750 0 C after 1 hr, but is not complete. The stress distributions are compared with those obtained from ferritic welds and the effect of differences in thermal expansion coefficients is examined using finite element analysis. (author)

Neutron stress measurement using image plate and the cos α method

International Nuclear Information System (INIS)

Sasaki, Toshihiko; Hirose, Yukio; Minakawa, Nobuaki; Morii, Yukio

2004-01-01

A new type of the neutron stress measurement method, in which the stress is determined by the cos α method, was studied. A neutron image plate was used in this study for detecting the diffraction image. Steel specimens of 5 mm thickness were used for the tensile stress test. The stresses obtain from the experiment showed one-to-one ratio with respect to the applied stresses, though the misfit stress of about 400 MPa was also observed in the result. A simple correction technique for calibrating raw data was proposed to obtain the true stress. A simulation study was carried out to check the experimental result on the peak positions in the diffraction ring and the stress calculation by the cos α method. (author)

Methods for predicting isochronous stress-strain curves

International Nuclear Information System (INIS)

Kiyoshige, Masanori; Shimizu, Shigeki; Satoh, Keisuke.

1976-01-01

Isochronous stress-strain curves show the relation between stress and total strain at a certain temperature with time as a parameter, and they are drawn up from the creep test results at various stress levels at a definite temperature. The concept regarding the isochronous stress-strain curves was proposed by McVetty in 1930s, and has been used for the design of aero-engines. Recently the high temperature characteristics of materials are shown as the isochronous stress-strain curves in the design guide for the nuclear energy equipments and structures used in high temperature creep region. It is prescribed that these curves are used as the criteria for determining design stress intensity or the data for analyzing the superposed effects of creep and fatigue. In case of the isochronous stress-strain curves used for the design of nuclear energy equipments with very long service life, it is impractical to determine the curves directly from the results of long time creep test, accordingly the method of predicting long time stress-strain curves from short time creep test results must be established. The method proposed by the authors, for which the creep constitution equations taking the first and second creep stages into account are used, and the method using Larson-Miller parameter were studied, and it was found that both methods were reliable for the prediction. (Kako, I.)

Interventions: Employees’ Perceptions of What Reduces Stress

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Silvia Pignata

2017-01-01

Full Text Available Objective. To build upon research evaluating stress interventions, this qualitative study tests the framework of the extended Job Demands-Resources model to investigate employees’ perceptions of the stress-reduction measures implemented at 13 Australian universities. Methods. In a cross-sectional survey design, tenured and contract staff indicated whether their overall level of stress had changed during the previous three-four years, and, if so, they described the major causes. A total of 462 staff reported that their level of stress had decreased; the study examines commentary from 115 academic and 304 nonacademic staff who provided details of what they perceived to be effective in reducing stress. Results. Thematic analyses show that the key perceived causes were changes in job or work role, new heads of departments or supervisors, and the use of organizational strategies to reduce or manage stress. A higher percentage of academic staff reported reduced stress due to using protective coping strategies or their increased recognition and/or success, whereas a higher percentage of nonacademic staff reported reduced stress due to increases in staffing resources and/or systems. Conclusion. These results identify the importance of implementing multilevel strategies to enhance employees’ well-being. Nonacademic staff, in particular, specified a variety of organizational stress-reduction interventions.

Is occupational stress associated with work engagement ?

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Padula, Rosimeire Simprini; Chiavegato, Luciana Dias; Cabral, Cristina Maria Nunes; Almeid, Talita; Ortiz, Thais; Carregaro, Rodrigo Luiz

2012-01-01

The occupational stress is associated with dissatisfaction, excessive demand at work and personal factors. Those factors can reduce work performance and can predispose workers to various diseases. Workers' health may be protected if there is encouragement to face challenges, which may lessen the impact on psychological and somatic stress and thus have greater personal and professional satisfaction. The aim of this study was to evaluate the association between occupational stress and work engagement. Participated in this study 457 male and female workers of a metallurgical industry. Subjects answered personal data, and the Job Stress Scale and Utrecht Work Engagement Scale were applied. Results showed an association between occupational stress and work engagement (P=0,001). The way the individual deals with his frustrations, or rather the work engagement, is associated with the occupational stress.

Work-related stress in midlife is associated with higher number of mobility limitation in older age-results from the FLAME study.

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Kulmala, Jenni; Hinrichs, Timo; Törmäkangas, Timo; von Bonsdorff, Mikaela B; von Bonsdorff, Monika E; Nygård, Clas-Håkan; Klockars, Matti; Seitsamo, Jorma; Ilmarinen, Juhani; Rantanen, Taina

2014-01-01

The aim of this study is to investigate whether work-related stress symptoms in midlife are associated with a number of mobility limitations during three decades from midlife to late life. Data for the study come from the Finnish Longitudinal Study of Municipal Employees (FLAME). The study includes a total of 5429 public sector employees aged 44-58 years at baseline who had information available on work-related stress symptoms in 1981 and 1985 and mobility limitation score during the subsequent 28-year follow-up. Four midlife work-related stress profiles were identified: negative reactions to work and depressiveness, perceived decrease in cognition, sleep disturbances, and somatic symptoms. People with a high number of stress symptoms in 1981 and 1985 were categorized as having constant stress. The number of self-reported mobility limitations was computed based on an eight-item list of mobility tasks presented to the participants in 1992, 1997, and 2009. Data were analyzed using joint Poisson regression models. The study showed that depending on the stress profile, persons suffering from constant stress in midlife had a higher risk of 30-70 % for having one more mobility limitation during the following 28 years compared to persons without stress after adjusting for mortality, several lifestyle factors, and chronic conditions. A less pronounced risk increase (20-40 %) was observed for persons with occasional symptoms. The study suggests that effective interventions aiming to reduce work-related stress should focus on both primary and secondary prevention.

Isothermal martensitic transformation as an internal-stress-increasing process

International Nuclear Information System (INIS)

Liu, Y.; Xie, Z.L.; Haenninen, H.; Humbeeck, J. van; Pietikaeinen, J.

1995-01-01

Based on the results that the magnitude of the stabilization of retained austenite increases with increasing the amount of martensite transformed, it has been assumed that the martensitic transformation is accompanied with an increase in internal resisting stress which subsequently results in the stabilization of retained austenite. By simplifying this internal resisting stress to be a type of hydrostatic compressive stress acting on retained austenite due to surrounding martensite plates, a thermodynamical analysis for an isothermal martensitic transformation under applied hydrostatic pressure has been performed. The calculated results, to some extent, show a good agreement with the experimental data. (orig.)

Interactive effects of stress and individual differences on alcohol use and posttraumatic stress disorder among personnel deployed to Guantanamo Bay.

Science.gov (United States)

De La Rosa, Gabriel M; Delaney, Eileen M; Webb-Murphy, Jennifer A; Johnston, Scott L

2015-11-01

This study examines the role of factors such as perceived stress, neuroticism, beliefs in psychotherapy stigma, resilience, and demographics in understanding posttraumatic stress disorder (PTSD) and alcohol use disorder (AUD) among deployed military personnel. Results show that personnel who screened positive for PTSD were more likely to screen positive for AUD (versus those who did not screen positive for PTSD). Perceived stress, neuroticism, and psychotherapy stigma all have direct multivariate relationships with PTSD symptoms. Moderated regression analyses show that the positive relationship between perceived stress and PTSD symptoms is significantly stronger among those scoring high on neuroticism and psychotherapy stigma. The positive relationship between perceived stress and AUD symptoms is only significant among those scoring high on psychotherapy stigma. Given the moderating role of psychotherapy stigma in the relationship between perceived stress and PTSD symptoms and the relationship between perceived stress and AUD symptoms efforts to reduce the stigma associated with mental health care in the military should be expanded. Also, the current research adds to the literature highlighting the role of neuroticism as a key variable in understanding PTSD. Copyright © 2015. Published by Elsevier Ltd.

Synergetic effects of radiation stress and hot-carrier stress on the current gain of npn bipolar junction transistors

International Nuclear Information System (INIS)

Witczak, S.C.; Kosier, S.L.; Schrimpf, R.D.; Galloway, K.F.

1994-01-01

The combined effects of ionizing radiation and hot-carrier stress on the current gain of npn bipolar junction transistors were investigated. The analysis was carried out experimentally by examining the consequences of interchanging the order in which the two stress types were applied to identical transistors which were stressed to various levels of damage. The results indicate that the hot-carrier response of the transistor is improved by radiation damage, whereas hot-carrier damage has little effect on subsequent radiation stress. Characterization of the temporal progression of hot-carrier effects revealed that hot-carrier stress acts initially to reduce excess base current and improve current gain in irradiated transistors. PISCES simulations show that the magnitude of the peak electric-field within the emitter-base depletion region is reduced significantly by net positive oxide charges induced by radiation. The interaction of the two stress types is explained in a qualitative model based on the probability of hot-carrier injection determined by radiation damage and on the neutralization and compensation of radiation-induced positive oxide charges by injected electrons. The result imply that a bound on damage due to the combined stress types is achieved when hot-carrier stress precedes any irradiation

Holographic stress tensor for non-relativistic theories

International Nuclear Information System (INIS)

Ross, Simon F.; Saremi, Omid

2009-01-01

We discuss the calculation of the field theory stress tensor from the dual geometry for two recent proposals for gravity duals of non-relativistic conformal field theories. The first of these has a Schroedinger symmetry including Galilean boosts, while the second has just an anisotropic scale invariance (the Lifshitz case). For the Lifshitz case, we construct an appropriate action principle. We propose a definition of the non-relativistic stress tensor complex for the field theory as an appropriate variation of the action in both cases. In the Schroedinger case, we show that this gives physically reasonable results for a simple black hole solution and agrees with an earlier proposal to determine the stress tensor from the familiar AdS prescription. In the Lifshitz case, we solve the linearised equations of motion for a general perturbation around the background, showing that our stress tensor is finite on-shell.

Work-related social support modulates effects of early life stress on limbic reactivity during stress.

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Leicht-Deobald, Ulrich; Bruch, Heike; Bönke, Luisa; Stevense, Amie; Fan, Yan; Bajbouj, Malek; Grimm, Simone

2017-12-15

Early life stress (ELS) affects stress- reactivity via limbic brain regions implicated such as hippocampus and amygdala. Social support is a major protective factor against ELS effects, while subjects with ELS experience reportedly perceive less of it in their daily life. The workplace, where most adults spend a substantial amount of time in their daily lives, might serve as a major resource for social support. Since previous data demonstrated that social support attenuates stress reactivity, we here used a psychosocial stress task to test the hypothesis that work-related social support modulates the effects of ELS. Results show decreased amygdala reactivity during stress in ELS subjects who report high levels of work- related social support, thereby indicating a signature for reduced stress reactivity. However, this effect was only observable on the neural, but not on the behavioral level, since social support had no buffering effect regarding the subjective experience of stress in daily life as well as regarding feelings of uncontrollability induced by the stress task. Accordingly, our data suggest that subjects with ELS experiences might benefit from interventions targeted at lowering their subjective stress levels by helping them to better perceive the availability of social support in their daily lives.

Workplace Stress Among Teachers in Kosovo

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Fleura Shkëmbi

2015-11-01

Full Text Available Teaching has been regarded as one of the most stressful professions, and workplace stress within this professional category has been thoroughly investigated. Nonetheless, no empirical research so far has examined workplace stress among teachers in Kosovo. The present study aimed to identify age and gender-related patterns of workplace stress as well as examine the role of marital status, educational level, and working experience in a sample of Kosovo teachers. The different types of stressors reported by teachers were also examined. The sample consisted of 799 teachers (Mage = 42.94; SD = 11.50, 33.8% males and 65.2% females. The measures included the National Stress Awareness Day (NSAD Stress Questionnaire, and one self-report questionnaire designed by the authors for the purpose of the research. Results showed that 33.2% (265 participants of the sample reported high levels of stress. Workplace stress was significantly predicted by place of residence (β = −.442, p < .00 and level of education (β = −.191, p < .00 but not age, gender, marital status, or working experience F(6, 520 = 34.162, p < .001, R2 = .283. As regards the specific stressors, the most frequently reported were inadequate wages (36.8%, physical working environment (30.1%, and undisciplined students (26.2%. Results are discussed in the context of practical implications they have and suggestions for future research are provided.

Occupations, perceived stress, and stress-related disorders among women and men in the public sector in Sweden.

Science.gov (United States)

Håkansson, Carita; Ahlborg, Gunnar

2017-01-01

Stress-related disorders are a public health problem and represent a significant burden to individuals and society. It is, therefore, of importance to regard stress in a wider context and identify risk factors not only at work but in all occupations in everyday life, to prevent ill health. The aim of this study was to examine potential associations between everyday occupations, perceived stress, and stress-related disorders as well as potential gender differences. A survey was mailed to a random selection of 3481 employees in the public sector in Western Sweden. Cox regressions with constant time at risk were used, in order to calculate prevalence ratios (PR) and their 95% confidence intervals (CI). The results showed a clear association between reporting imbalance between different everyday occupations and both perceived stress and stress-related disorders among men and women. Imbalance between different everyday occupations seems to be an important risk factor for perceived stress and stress-related disorder among both women and men. To enable people to achieve balance between different everyday occupations may be a useful way to prevent stress, stress-related disorders, and sick leave, and to promote better health and well-being.

Superposition of Stress Fields in Diametrically Compressed Cylinders

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João Augusto de Lima Rocha

Full Text Available Abstract The theoretical analysis for the Brazilian test is a classical plane stress problem of elasticity theory, where a vertical force is applied to a horizontal plane, the boundary of a semi-infinite medium. Hypothesizing a normal radial stress field, the results of that model are correct. Nevertheless, the superposition of three stress fields, with two being based on prior results and the third based on a hydrostatic stress field, is incorrect. Indeed, this work shows that the Cauchy vectors (tractions are non-vanishing in the parallel planes in which the two opposing vertical forces are applied. The aim of this work is to detail the process used in the construction of the theoretical model for the three stress fields used, with the objective being to demonstrate the inconsistency often stated in the literature.

Status inconsistency in groups : How discrepancies between instrumental and expressive status result in symptoms of stress

NARCIS (Netherlands)

van de Brake, Hendrik; Grow, André; Dijkstra, Jan Kornelis

This study examines whether a mismatch between the positions that individuals hold in different status hierarchies results in symptoms of stress. Prior research has focused on inconsistencies between socioeconomic status dimensions (e.g., education and income) and did not find a significant relation

The interaction of fatigue cracks with a residual stress field using thermoelastic stress analysis and synchrotron X-ray diffraction experiments

Science.gov (United States)

Amjad, Khurram; Asquith, David; Sebastian, Christopher M.; Wang, Wei-Chung

2017-01-01

This article presents an experimental study on the fatigue behaviour of cracks emanating from cold-expanded holes utilizing thermoelastic stress analysis (TSA) and synchrotron X-ray diffraction (SXRD) techniques with the aim of resolving the long-standing ambiguity in the literature regarding potential relaxation, or modification, of beneficial compressive residual stresses as a result of fatigue crack propagation. The crack growth rates are found to be substantially lower as the crack tip moved through the residual stress zone induced by cold expansion. The TSA results demonstrated that the crack tip plastic zones were reduced in size by the presence of the residual compressive stresses induced by cold expansion. The crack tip plastic zones were found to be insignificant in size in comparison to the residual stress zone resulting from cold expansion, which implied that they were unlikely to have had a notable impact on the surrounding residual stresses induced by cold expansion. The residual stress distributions measured along the direction of crack growth, using SXRD, showed no signs of any significant stress relaxation or redistribution, which validates the conclusions drawn from the TSA data. Fractographic analysis qualitatively confirmed the influence on crack initiation of the residual stresses induced by the cold expansion. It was found that the application of single compressive overload caused a relaxation, or reduction in the residual stresses, which has wider implications for improving the fatigue life. PMID:29291095

Compelling Evidence of the Need for Corporate Work/Life Balance Initiatives: Results from a National Survey of Stressful Life-Events.

Science.gov (United States)

Hobson, Charles J.; Delunas, Linda; Kesic, Dawn

2001-01-01

Considers how failure to balance excessive work and life/family demands can lead to negative consequences for both individuals and organizations, including higher stress levels, increased absenteeism, and lower productivity. Discusses results of a survey on stressful life events that offers an explanation of why work/life balance programs are so…

Stress in ion-implanted CVD Si3N4 films

International Nuclear Information System (INIS)

EerNisse, E.P.

1977-01-01

The compressive stress buildup caused in chemical-vapor-deposited (CVD) Si 3 N 4 films by ion implantation is shown to be caused entirely by atomic collision effects, ionization effects being unimportant. The stress introduction rate is shown to be independent of CVD processing variables and O content of the film. The maximum attainable compressive stress change is 3.5 x 10 10 dyn/cm 2 , resulting in a maximum net compressive stress of 2 x 10 10 dyn/cm 2 for films on Si where the as-deposited films inherently have 1.5 x 10 10 dyn/cm 2 tensile stress before ion implantation. Results are presented which show that O in the films inhibits thermal annealing of the ion-implantation-induced compressive stress. Results for introduction rate and annealing effects are presented in normalized form so that workers can use the effects for intentional stress level adjustment in the films to reduce probability of cracking and detachment

Stress-induced hyperthermia in translational stress research

NARCIS (Netherlands)

Vinkers, C.H.; Penning, R.; Ebbens, M.M.; Helhammer, J.; Verster, J.C.; Kalkman, C.J.; Olivier, B.

2010-01-01

The stress-induced hyperthermia (SIH) response is the transient change in body temperature in response to acute stress. This body temperature response is part of the autonomic stress response which also results in tachycardia and an increased blood pressure. So far, a SIH response has been found in

Demographic differences, occupational stress and organisational commitment among employees in higher education institution

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Simbarashe Zhuwao

2015-11-01

Full Text Available The objectives of this study was to determine the levels of occupational stress and organizational commitment of employees and to determine the differences of occupational stress and organisational commitment based on demographic information in a higher education institution. The sample consisted of 141 academic staff. The Organisational Stress Screening Tool (ASSET, and Allen and Meyer’s Organisational Commitment Tool (OCT were used. The results showed that different occupational stressors contributed significantly to low organisational commitment. Occupational stress levels about job characteristics, work relationships, job overload and job control contributed to low levels of organisational commitment. The results also showed that there is a significant difference in occupational stress and organisational commitment levels based on the demographic differences of employees

Aspergillus oryzae AoSO is a novel component of stress granules upon heat stress in filamentous fungi.

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Hsiang-Ting Huang

Full Text Available Stress granules are a type of cytoplasmic messenger ribonucleoprotein (mRNP granule formed in response to the inhibition of translation initiation, which typically occurs when cells are exposed to stress. Stress granules are conserved in eukaryotes; however, in filamentous fungi, including Aspergillus oryzae, stress granules have not yet been defined. For this reason, here we investigated the formation and localization of stress granules in A. oryzae cells exposed to various stresses using an EGFP fusion protein of AoPab1, a homolog of Saccharomyces cerevisiae Pab1p, as a stress granule marker. Localization analysis showed that AoPab1 was evenly distributed throughout the cytoplasm under normal growth conditions, and accumulated as cytoplasmic foci mainly at the hyphal tip in response to stress. AoSO, a homolog of Neurospora crassa SO, which is necessary for hyphal fusion, colocalized with stress granules in cells exposed to heat stress. The formation of cytoplasmic foci of AoSO was blocked by treatment with cycloheximide, a known inhibitor of stress granule formation. Deletion of the Aoso gene had effects on the formation and localization of stress granules in response to heat stress. Our results suggest that AoSO is a novel component of stress granules specific to filamentous fungi. The authors would specially like to thank Hiroyuki Nakano and Kei Saeki for generously providing experimental and insightful opinions.

Natural Variation in Stress Hormones, Comparisons Across Matrices, and Impacts Resulting from Induced Stress in the Bottlenose Dolphin.

Science.gov (United States)

Houser, Dorian S; Champagne, Cory D; Crocker, Daniel E; Kellar, Nicholas M; Cockrem, John; Romano, Tracy; Booth, Rebecca K; Wasser, Samuel K

2016-01-01

Knowledge regarding stress hormones and how they vary in response to seasonality, gender, age, and reproductive status for any marine mammal is limited. Furthermore, stress hormones may be measured in more than one matrix (e.g., feces, blood, blubber), but the relationships between levels of a given hormone across these matrices are unknown, further complicating the interpretations of hormones measured in samples collected from wild animals. A study is underway to address these issues in a population of bottlenose dolphins trained for voluntary participation in sample collections from different matrices and across season and time of day.

The three catalases in Deinococcus radiodurans: Only two show catalase activity

Energy Technology Data Exchange (ETDEWEB)

Jeong, Sun-Wook [Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, 580-185 (Korea, Republic of); Department of Biological Sciences, College of Biological Sciences and Biotechnology, Chungnam National University, Daejeon, 305-764 (Korea, Republic of); Jung, Jong-Hyun; Kim, Min-Kyu; Seo, Ho Seong [Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, 580-185 (Korea, Republic of); Lim, Heon-Man [Department of Biological Sciences, College of Biological Sciences and Biotechnology, Chungnam National University, Daejeon, 305-764 (Korea, Republic of); Lim, Sangyong, E-mail: saylim@kaeri.re.kr [Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, 580-185 (Korea, Republic of)

2016-01-15

Deinococcus radiodurans, which is extremely resistant to ionizing radiation and oxidative stress, is known to have three catalases (DR1998, DRA0146, and DRA0259). In this study, to investigate the role of each catalase, we constructed catalase mutants (Δdr1998, ΔdrA0146, and ΔdrA0259) of D. radiodurans. Of the three mutants, Δdr1998 exhibited the greatest decrease in hydrogen peroxide (H{sub 2}O{sub 2}) resistance and the highest increase in intracellular reactive oxygen species (ROS) levels following H{sub 2}O{sub 2} treatments, whereas ΔdrA0146 showed no change in its H{sub 2}O{sub 2} resistance or ROS level. Catalase activity was not attenuated in ΔdrA0146, and none of the three bands detected in an in-gel catalase activity assay disappeared in ΔdrA0146. The purified His-tagged recombinant DRA0146 did not show catalase activity. In addition, the phylogenetic analysis of the deinococcal catalases revealed that the DR1998-type catalase is common in the genus Deinococcus, but the DRA0146-type catalase was found in only 4 of 23 Deinococcus species. Taken together, these results indicate that DR1998 plays a critical role in the anti-oxidative system of D. radiodurans by detoxifying H{sub 2}O{sub 2}, but DRA0146 does not have catalase activity and is not involved in the resistance to H{sub 2}O{sub 2} stress. - Highlights: • The dr1998 mutant strain lost 90% of its total catalase activity. • Increased ROS levels and decreased H{sub 2}O{sub 2} resistance were observed in dr1998 mutants. • Lack of drA0146 did not affect any oxidative stress-related phenotypes. • The purified DRA0146 did not show catalase activity.

The three catalases in Deinococcus radiodurans: Only two show catalase activity

International Nuclear Information System (INIS)

Jeong, Sun-Wook; Jung, Jong-Hyun; Kim, Min-Kyu; Seo, Ho Seong; Lim, Heon-Man; Lim, Sangyong

2016-01-01

Deinococcus radiodurans, which is extremely resistant to ionizing radiation and oxidative stress, is known to have three catalases (DR1998, DRA0146, and DRA0259). In this study, to investigate the role of each catalase, we constructed catalase mutants (Δdr1998, ΔdrA0146, and ΔdrA0259) of D. radiodurans. Of the three mutants, Δdr1998 exhibited the greatest decrease in hydrogen peroxide (H_2O_2) resistance and the highest increase in intracellular reactive oxygen species (ROS) levels following H_2O_2 treatments, whereas ΔdrA0146 showed no change in its H_2O_2 resistance or ROS level. Catalase activity was not attenuated in ΔdrA0146, and none of the three bands detected in an in-gel catalase activity assay disappeared in ΔdrA0146. The purified His-tagged recombinant DRA0146 did not show catalase activity. In addition, the phylogenetic analysis of the deinococcal catalases revealed that the DR1998-type catalase is common in the genus Deinococcus, but the DRA0146-type catalase was found in only 4 of 23 Deinococcus species. Taken together, these results indicate that DR1998 plays a critical role in the anti-oxidative system of D. radiodurans by detoxifying H_2O_2, but DRA0146 does not have catalase activity and is not involved in the resistance to H_2O_2 stress. - Highlights: • The dr1998 mutant strain lost 90% of its total catalase activity. • Increased ROS levels and decreased H_2O_2 resistance were observed in dr1998 mutants. • Lack of drA0146 did not affect any oxidative stress-related phenotypes. • The purified DRA0146 did not show catalase activity.

Seed priming with hormones does not alleviate induced oxidative stress in maize seedlings subjected to salt stress

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Rogério Falleiros Carvalho

2011-10-01

Full Text Available Seed priming with hormones has been an efficient method for increasing seed vigor as well as seedling growth under stressful conditions. These responses have in the past been attributed to the activation of antioxidant systems in a range of crops. The results described in this work show that hormonal priming with methyl jasmonate, salicylic acid or CEPA (chloroethylphosphonic acid, an ethylene (ET releaser, does not induce the antioxidant activity of superoxide dismutase, catalase, ascorbate peroxidase or glutathione reductase in maize seedlings subjected to salt stress. The enhanced biomass of maize seedlings under salt stress that was observed only from ET priming indicates that the stress tolerance in maize from ethylene priming is a fundamental process for stress tolerance acquisition, which is explained, however, by other biochemical mechanisms but not by changes in the antioxidant system.

Serendipity: Global Detection and Quantification of Plant Stress

Science.gov (United States)

Schimel, D.; Verma, M.; Drewry, D.

2016-12-01

Detecting and quantifying plant stress is a grand challenge for remote sensing, and is important for understanding climate impacts on ecosystems broadly and also for early warning systems supporting food security. The long record from moderate resolution sensors providing frequent data has allowed using phenology to detect stress in forest and agroecosystems, but can fail or give ambiguous results when stress occurs during later phases of growth and in high leaf area systems. The recent recognition that greenhouse gas satellites such as GOSAT and OCO-2 observe Solar-Induced Fluorescence has added a new and complementary tool for the quantification of stress but algorithms to detect and quantify stress using SIF are in their infancy. Here we report new results showing a more complex response of SIF to stress by evaluating spaceborne SIF against in situ eddy covariance data. The response observed is as predicted by theory, and shows that SIF, used in conjunction with moderate resolution remote sensing, can detect and likely quantify stress by indexing the nonlinear part of the SIF-GPP relationship using the photochemical reflectance index and remotely observed light absorption. There are several exciting opportunities on the near horizon for the implementation of SIF, together with syngeristic measurements such as PRI and evapotranspiration that suggest the next few years will be a golden age for global ecology. Adancing the science and associated algorithms now is essential to fully exploiting the next wave of missions.

REPEATED ACUTE STRESS INDUCED ALTERATIONS IN CARBOHYDRATE METABOLISM IN RAT

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Nirupama R.

2010-09-01

Full Text Available Acute stress induced alterations in the activity levels of rate limiting enzymes and concentration of intermediates of different pathways of carbohydrate metabolism have been studied. Adult male Wistar rats were restrained (RS for 1 h and after an interval of 4 h they were subjected to forced swimming (FS exercise and appropriate controls were maintained. Five rats were killed before the commencement of the experiment (initial controls, 5 control and equal number of stressed rats were killed 2 h after RS and remaining 5 rats in each group were killed 4 h after FS. There was a significant increase in the adrenal 3β- hydroxy steroid dehydrogenase activity following RS, which showed further increase after FS compared to controls and thereby indicated stress response of rats. There was a significant increase in the blood glucose levels following RS which showed further increase and reached hyperglycemic condition after FS. The hyperglycemic condition due to stress was accompanied by significant increases in the activities of glutamate- pyruvate transaminase, glutamate- oxaloacetate transaminase, glucose -6- phosphatase and lactate dehydrogenase and significant decrease in the glucose -6- phosphate dehydrogenase and pyruvate dehydrogenase activities, whereas pyruvate kinase activity did not show any alteration compared to controls. Further, the glycogen and total protein contents of the liver were decreased whereas those of pyruvate and lactate showed significant increase compared to controls after RS as well as FS.The results put together indicate that acute stress induced hyperglycemia results due to increased gluconeogenesis and glycogenolysis without alteration in glycolysis. The study first time reveals that after first acute stress exposure, the subsequent stressful experience augments metabolic stress response leading to hyperglycemia. The results have relevance to human health as human beings are exposed to several stressors in a day and

Estimation of stress distribution in ferromagnetic tensile specimens using low cost eddy current stress measurement system and BP neural network.

Science.gov (United States)

Li, Jianwei; Zhang, Weimin; Zeng, Weiqin; Chen, Guolong; Qiu, Zhongchao; Cao, Xinyuan; Gao, Xuanyi

2017-01-01

Estimation of the stress distribution in ferromagnetic components is very important for evaluating the working status of mechanical equipment and implementing preventive maintenance. Eddy current testing technology is a promising method in this field because of its advantages of safety, no need of coupling agent, etc. In order to reduce the cost of eddy current stress measurement system, and obtain the stress distribution in ferromagnetic materials without scanning, a low cost eddy current stress measurement system based on Archimedes spiral planar coil was established, and a method based on BP neural network to obtain the stress distribution using the stress of several discrete test points was proposed. To verify the performance of the developed test system and the validity of the proposed method, experiment was implemented using structural steel (Q235) specimens. Standard curves of sensors at each test point were achieved, the calibrated data were used to establish the BP neural network model for approximating the stress variation on the specimen surface, and the stress distribution curve of the specimen was obtained by interpolating with the established model. The results show that there is a good linear relationship between the change of signal modulus and the stress in most elastic range of the specimen, and the established system can detect the change in stress with a theoretical average sensitivity of -0.4228 mV/MPa. The obtained stress distribution curve is well consonant with the theoretical analysis result. At last, possible causes and improving methods of problems appeared in the results were discussed. This research has important significance for reducing the cost of eddy current stress measurement system, and advancing the engineering application of eddy current stress testing.

Good stress, bad stress and oxidative stress: insights from anticipatory cortisol reactivity.

Science.gov (United States)

Aschbacher, Kirstin; O'Donovan, Aoife; Wolkowitz, Owen M; Dhabhar, Firdaus S; Su, Yali; Epel, Elissa

2013-09-01

Chronic psychological stress appears to accelerate biological aging, and oxidative damage is an important potential mediator of this process. However, the mechanisms by which psychological stress promotes oxidative damage are poorly understood. This study investigates the theory that cortisol increases in response to an acutely stressful event have the potential to either enhance or undermine psychobiological resilience to oxidative damage, depending on the body's prior exposure to chronic psychological stress. In order to achieve a range of chronic stress exposure, forty-eight post-menopausal women were recruited in a case-control design that matched women caring for spouses with dementia (a chronic stress model) with similarly aged control women whose spouses were healthy. Participants completed a questionnaire assessing perceived stress over the previous month and provided fasting blood. Three markers of oxidative damage were assessed: 8-iso-prostaglandin F(2α) (IsoP), lipid peroxidation, 8-hydroxyguanosine (8-oxoG) and 8-hydroxy-2'-deoxyguanosine (8-OHdG), reflecting oxidative damage to RNA/DNA respectively. Within approximately one week, participants completed a standardized acute laboratory stress task while salivary cortisol responses were measured. The increase from 0 to 30 min was defined as "peak" cortisol reactivity, while the increase from 0 to 15 min was defined as "anticipatory" cortisol reactivity, representing a cortisol response that began while preparing for the stress task. Women under chronic stress had higher 8-oxoG, oxidative damage to RNA (pstress and elevated oxidative stress damage, but only among women under chronic stress. Consistent with this model, bootstrapped path analysis found significant indirect paths from perceived stress to 8-oxoG and IsoP (but not 8-OHdG) via anticipatory cortisol reactivity, showing the expected relations among chronically stressed participants (p≤.01) Intriguingly, among those with low chronic stress

Radioisotopic and Radiological Evaluation in Patient with Stress Fracture

International Nuclear Information System (INIS)

Ko, Kwang Seop; Kim, Jai Young; Kang, Sung Koo; Kim, So Yon; Lee, Gwon Jun

1987-01-01

The stress fracture is a disease caused by and abnormal stress to the normal bone with constant, repeated pull. Early detection of stress fracture plays an important role in treatment and prevention of its complication. Bone scintigraphy was performed to evaluate 18 patients with stress fracture of the lower extremities from May, 1985 to April, 1987, in the Department of Internal Medicine of National Police Hospital. The results were as follows: 1) Seventeen of the 18 cases showed positive bone scans at the initial study performed from 1 week to 5 months after the onset of symptom. 2) Ten of the 18 patients had findings of stress fracture at the initial X-ray film. Two out of 8 negative case revealed positive findings in the follow-up studies. 3) The bone scans in the 2 cases taken 5 months after the onset of symptom; the one showed only slightly increased radio uptake, the other showed no abnormal findings. In conclusion, bone scanning is a more sensitive indicator of early stress fracture than radiologic study, The healing phase is characterized by a gradual decline in radioactivity at the fracture site in concordance with subsidence of symptom.

Frequency and Wavevector Dependence of the Atomic Level Stress-Stress Correlation Function in a Model Supercooled Liquid

Science.gov (United States)

Levashov, Valentin A.; Morris, James R.; Egami, Takeshi

2012-02-01

Temporal and spatial correlations among the local atomic level shear stresses were studied for a model liquid iron by molecular dynamics simulation [PRL 106,115703]. Integration over time and space of the shear stress correlation function F(r,t) yields viscosity via Green-Kubo relation. The stress correlation function in time and space F(r,t) was Fourier transformed to study the dependence on frequency, E, and wave vector, Q. The results, F(Q,E), showed damped shear stress waves propagating in the liquid for small Q at high and low temperatures. We also observed additional diffuse feature that appears as temperature is reduced below crossover temperature of potential energy landscape at relatively low frequencies at small Q. We suggest that this additional feature might be related to dynamic heterogeneity and boson peaks. We also discuss a relation between the time-scale of the stress-stress correlation function and the alpha-relaxation time of the intermediate self-scattering function S(Q,E).

Effect of the weld joint configuration on stressed components, residual stresses and mechanical properties

Energy Technology Data Exchange (ETDEWEB)

Cevik, Bekir; Oezer, Alpay; Oezcatalbas, Yusuf [Gazi Univ., Ankara (Turkey)

2014-03-01

The effect of the weld joint configuration on components has been studied, which are under service loads, under repair or construction and the residual stresses as well as the mechanical properties of the joint have been determined. For this purpose, a horizontal positioned tensile testing device and a semi-automatic MIG welding machine have been used and then the weld joints of the plates were subjected to different elastic stresses. When the temperature of the joined elements decreased to room temperature, applied elastic stresses were released. By this means, the effects of the existing tensile stresses in the joined parts and the tensile stresses created by the welding processes were investigated. The tensile stresses occurring in the joined elements were determined by using the photo-elasticity analysis method and the hole-drilling method. Also, tensile-shear tests were applied in order to determine the effect of permanent tensile loads on the mechanical properties of the joint. Experimental results showed that the application of corner welded lap joints for components under tensile loading significantly decrease the shear strength and yielding capacities of the joint. (orig.)

Quantifying the Effect of Stress on Sn Whisker Nucleation Kinetics

Science.gov (United States)

Chason, Eric; Vasquez, Justin; Pei, Fei; Jain, Nupur; Hitt, Andrew

2018-01-01

Although Sn whiskers have been studied extensively, there is still a need to understand the driving forces behind whisker nucleation and growth. Many studies point to the role of stress, but confirming this requires a quantitative comparison between controlled stress and the resulting whisker evolution. Recent experimental studies applied stress to a Sn layer via thermal cycling and simultaneously monitored the evolution of the temperature, stress and number of nuclei. In this work, we analyze these nucleation kinetics in terms of classical nucleation theory to relate the observed behavior to underlying mechanisms including a stress dependent activation energy and a temperature and stress-dependent whisker growth rate. Non-linear least squares fitting of the data taken at different temperatures and strain rates to the model shows that the results can be understood in terms of stress decreasing the barrier for whisker nucleation.

Oxidative stress adaptation with acute, chronic, and repeated stress.

Science.gov (United States)

Pickering, Andrew M; Vojtovich, Lesya; Tower, John; A Davies, Kelvin J

2013-02-01

Oxidative stress adaptation, or hormesis, is an important mechanism by which cells and organisms respond to, and cope with, environmental and physiological shifts in the level of oxidative stress. Most studies of oxidative stress adaption have been limited to adaptation induced by acute stress. In contrast, many if not most environmental and physiological stresses are either repeated or chronic. In this study we find that both cultured mammalian cells and the fruit fly Drosophila melanogaster are capable of adapting to chronic or repeated stress by upregulating protective systems, such as their proteasomal proteolytic capacity to remove oxidized proteins. Repeated stress adaptation resulted in significant extension of adaptive responses. Repeated stresses must occur at sufficiently long intervals, however (12-h or more for MEF cells and 7 days or more for flies), for adaptation to be successful, and the levels of both repeated and chronic stress must be lower than is optimal for adaptation to acute stress. Regrettably, regimens of adaptation to both repeated and chronic stress that were successful for short-term survival in Drosophila nevertheless also caused significant reductions in life span for the flies. Thus, although both repeated and chronic stress can be tolerated, they may result in a shorter life. Copyright © 2012 Elsevier Inc. All rights reserved.

Tensile Stress-Strain Results for 304L and 316L Stainless-Steel Plate at Temperature

International Nuclear Information System (INIS)

R. K. Blandford; D. K. Morton; S. D. Snow; T. E. Rahl

2007-01-01

The Idaho National Laboratory (INL) is conducting moderate strain rate (10 to 200 per second) research on stainless steel materials in support of the Department of Energy's (DOE) National Spent Nuclear Fuel Program (NSNFP). For this research, strain rate effects are characterized by comparison to quasi-static tensile test results. Considerable tensile testing has been conducted resulting in the generation of a large amount of basic material data expressed as engineering and true stress-strain curves. The purpose of this paper is to present the results of quasi-static tensile testing of 304/304L and 316/316L stainless steels in order to add to the existing data pool for these materials and make the data more readily available to other researchers, engineers, and interested parties. Standard tensile testing of round specimens in accordance with ASTM procedure A 370-03a were conducted on 304L and 316L stainless-steel plate materials at temperatures ranging from -20 F to 600 F. Two plate thicknesses, eight material heats, and both base and weld metal were tested. Material yield strength, Young's modulus, ultimate strength, ultimate strain, failure strength and failure strain were determined, engineering and true stress-strain curves to failure were developed, and comparisons to ASME Code minimums were made. The procedures used during testing and the typical results obtained are described in this paper

A 2-Year Holistic Health and Stress Intervention: Results of an RCT in Clergy.

Science.gov (United States)

Proeschold-Bell, Rae Jean; Turner, Elizabeth L; Bennett, Gary G; Yao, Jia; Li, Xiang-Fang; Eagle, David E; Meyer, Rachel A; Williams, Redford B; Swift, Robin Y; Moore, H Edgar; Kolkin, Melanie A; Weisner, Carl C; Rugani, Katherine M; Hough, Holly J; Williams, Virginia P; Toole, David C

2017-09-01

This study sought to determine the effect of a 2-year, multicomponent health intervention (Spirited Life) targeting metabolic syndrome and stress simultaneously. An RCT using a three-cohort multiple baseline design was conducted in 2010-2014. Participants were United Methodist clergy in North Carolina, U.S., in 2010, invited based on occupational status. Of invited 1,745 clergy, 1,114 consented, provided baseline data, and were randomly assigned to immediate intervention (n=395), 1-year waitlist (n=283), or 2-year waitlist (n=436) cohorts for a 48-month trial duration. The 2-year intervention consisted of personal goal setting and encouragement to engage in monthly health coaching, an online weight loss intervention, a small grant, and three workshops delivering stress management and theological content supporting healthy behaviors. Participants were not blinded to intervention. Trial outcomes were metabolic syndrome (primary) and self-reported stress and depressive symptoms (secondary). Intervention effects were estimated in 2016 in an intention-to-treat framework using generalized estimating equations with adjustment for baseline level of the outcome and follow-up time points. Log-link Poisson generalized estimating equations with robust SEs was used to estimate prevalence ratios (PRs) for binary outcomes; mean differences were used for continuous/score outcomes. Baseline prevalence of metabolic syndrome was 50.9% and depression was 11.4%. The 12-month intervention effect showed a benefit for metabolic syndrome (PR=0.86, 95% CI=0.79, 0.94, pstress scores. The Spirited Life intervention improved metabolic syndrome prevalence in a population of U.S. Christian clergy and sustained improvements during 24 months of intervention. These findings offer support for long-duration behavior change interventions and population-level interventions that allow participants to set their own health goals. This study is registered at www.clinicaltrials.gov NCT01564719. Copyright �

Anticipatory stress influences decision making under explicit risk conditions.

Science.gov (United States)

Starcke, Katrin; Wolf, Oliver T; Markowitsch, Hans J; Brand, Matthias

2008-12-01

Recent research has suggested that stress may affect memory, executive functioning, and decision making on the basis of emotional feedback processing. The current study examined whether anticipatory stress affects decision making measured with the Game of Dice Task (GDT), a decision-making task with explicit and stable rules that taps both executive functioning and feedback learning. The authors induced stress in 20 participants by having them anticipate giving a public speech and also examined 20 comparison subjects. The authors assessed the level of stress with questionnaires and endocrine markers (salivary cortisol and alpha-amylase), both revealing that speech anticipation led to increased stress. Results of the GDT showed that participants under stress scored significantly lower than the comparison group and that GDT performance was negatively correlated with the increase of cortisol. Our results indicate that stress can lead to disadvantageous decision making even when explicit and stable information about outcome contingencies is provided.

Stress prompts habit behavior in humans.

Science.gov (United States)

Schwabe, Lars; Wolf, Oliver T

2009-06-03

Instrumental behavior can be controlled by goal-directed action-outcome and habitual stimulus-response processes that are supported by anatomically distinct brain systems. Based on previous findings showing that stress modulates the interaction of "cognitive" and "habit" memory systems, we asked in the presented study whether stress may coordinate goal-directed and habit processes in instrumental learning. For this purpose, participants were exposed to stress (socially evaluated cold pressor test) or a control condition before they were trained to perform two instrumental actions that were associated with two distinct food outcomes. After training, one of these food outcomes was selectively devalued as subjects were saturated with that food. Next, subjects were presented the two instrumental actions in extinction. Stress before training in the instrumental task rendered participants' behavior insensitive to the change in the value of the food outcomes, that is stress led to habit performance. Moreover, stress reduced subjects' explicit knowledge of the action-outcome contingencies. These results demonstrate for the first time that stress promotes habits at the expense of goal-directed performance in humans.

Dietary intake of Deepwater Horizon oil-injected live food fish by double-crested cormorants resulted in oxidative stress.

Science.gov (United States)

Pritsos, Karen L; Perez, Cristina R; Muthumalage, Thivanka; Dean, Karen M; Cacela, Dave; Hanson-Dorr, Katie; Cunningham, Fred; Bursian, Steven J; Link, Jane E; Shriner, Susan; Horak, Katherine; Pritsos, Chris A

2017-12-01

The Deepwater Horizon oil spill released 134 million gallons of crude oil into the Gulf of Mexico making it the largest oil spill in US history and exposing fish, birds, and marine mammals throughout the Gulf of Mexico to its toxicity. Fish eating waterbirds such as the double-crested cormorant (Phalacrocorax auritus) were exposed to the oil both by direct contact with the oil and orally through preening and the ingestion of contaminated fish. This study investigated the effects of orally ingestedMC252 oil-contaminated live fish food by double-crested cormorants on oxidative stress. Total, reduced, and oxidized glutathione levels, superoxide dismutase and glutathione peroxidase activities, total antioxidant capacity and lipid peroxidation were assessed in the liver tissues of control and treated cormorants. The results suggest that ingestion of the oil-contaminated fish resulted in significant increase in oxidative stress in the liver tissues of these birds. The oil-induced increase in oxidative stress could have detrimental impacts on the bird's life-history. Copyright © 2017 Elsevier Inc. All rights reserved.

A Conceptual Framework to Address Stress-Associated ...

Science.gov (United States)

Chronic stress leads to a variety of mental and physiological disorders, and stress effects are the primary concern after traumatic injury and exposure to infectious diseases or toxic agents from disaster events. We developed a conceptual model to address the question of whether degradation of ecosystem services (ES) by disasters such as recent hurricanes and the Deepwater Horizon oil catastrophe produce acute and chronic stress that ultimately result in short- and long-term negative health outcomes in people. An interdisciplinary team with expertise in data mining, ecology, ecosystem services, ecotoxicology, landscape ecology, mental health, psychiatry, and stress physiology utilized the Driver-Pressure-State-Ecosystem Service model of Kelble et al. (2013), the mental health framework of Palinkas (2012) and McEwen’s (1993) allostatic load model of chronic stress as starting points. Initial modeling results were augmented via expert workshops and peer review. Our conceptual model connects effects of disasters to changes in specific ecosystem components (e.g., water quality, biodiversity, fishery populations) with resulting degradation of multiple ES such as commercial and recreational fishing, tourism, and sense of place. The model shows how the degraded ES produce acute and chronic stress in people and how such stress may lead to a variety of negative mental, physical and behavioral health outcomes. Using this framework, one can trace potential for str

The influence of psychological stress on upper respiratory infection

DEFF Research Database (Denmark)

Pedersen, Anette Fischer; Zachariae, Robert; Bovberg, Dana

2010-01-01

OBJECTIVE: To quantify the available evidence for the hypothesis that reduced resistance caused by psychological stress may influence the development of clinical disease in those exposed to an infectious agent. METHODS: We conducted a systematic review and meta-analysis of 27 prospective studies...... examining the association between psychological stress and subsequent upper respiratory infection (URI). RESULTS: The results revealed a significant overall main effect of psychological stress on the risk of developing URI (effect size correlation coefficient, 0.21; 95% confidence interval, 0.......15-0.27). Further analyses showed that effect sizes for the association did not vary according to type of stress, how URI was assessed, or whether the studies had controlled for preexposure. CONCLUSIONS: The meta-analytical findings confirmed the hypothesis that psychological stress is associated with increased...

Some remarks on the analysis of stress-corrosion cracking of austenitic stainless-steel cladding

International Nuclear Information System (INIS)

Kupka, I.; Nrkous, P.

1977-01-01

Stress-corrosion cracking is greatly influenced by tensile stresses in the material. The occurrence of tensile stresses in the material under consideration results from residual stresses brought about during manufacturing processes and from stress caused by operation. In the case of an austenitic steel cladding the residual stresses arise in the course of welding and thermal treatment. The technique of residual stress measurement in austenitic cladding materials is described and the results are given. Both the longitudinal and transverse components of the stresses show in all cases similar behaviour not only prior to, but also after heat treatment. (J.B.)

A BDNF sensitive mechanism is involved in the fear memory resulting from the interaction between stress and the retrieval of an established trace.

Science.gov (United States)

Giachero, Marcelo; Bustos, Silvia G; Calfa, Gaston; Molina, Victor A

2013-04-15

The present study investigates the fear memory resulting from the interaction of a stressful experience and the retrieval of an established fear memory trace. Such a combination enhanced both fear expression and fear retention in adult Wistar rats. Likewise, midazolam intra-basolateral amygdala (BLA) infusion prior to stress attenuated the enhancement of fear memory thus suggesting the involvement of a stress-induced reduction of the GABAergic transmission in BLA in the stress-induced enhancing effect. It has been suggested that, unlike the immediate-early gene Zif268 which is related to the reconsolidation process, the expression of hippocampal brain-derived neurotrophic factor (BDNF) is highly correlated with consolidation. We therefore evaluate the relative contribution of these two neurobiological processes to the fear memory resulting from the above-mentioned interaction. Intra-dorsal hippocampus (DH) infusions of either the antisense Zif268 or the inhibitor of the protein degradation (Clasto-Lactacystin β-Lactone), suggested to be involved in the retrieval-dependent destabilization process, did not affect the resulting contextual memory. In contrast, the knockdown of hippocampal BDNF mitigated the stress-induced facilitating influence on fear retention. In addition, the retrieval experience elevated BDNF level in DH at 60 min after recall exclusively in stressed animals. These findings suggest the involvement of a hippocampal BDNF sensitive mechanism in the stress-promoting influence on the fear memory following retrieval.

Effect of supplemental Ascorbic acid and disturbance stress on the ...

African Journals Online (AJOL)

Effect of supplemental Ascorbic acid and disturbance stress on the performance of broiler chickens. ... Nigerian Journal of Animal Production ... Results showed that there were no significant interactions between dietary ascorbic acid supplementation and disturbance stress levels on any of the performance data considered.

Underground water stress release models

Science.gov (United States)

Li, Yong; Dang, Shenjun; Lü, Shaochuan

2011-08-01

The accumulation of tectonic stress may cause earthquakes at some epochs. However, in most cases, it leads to crustal deformations. Underground water level is a sensitive indication of the crustal deformations. We incorporate the information of the underground water level into the stress release models (SRM), and obtain the underground water stress release model (USRM). We apply USRM to the earthquakes occurred at Tangshan region. The analysis shows that the underground water stress release model outperforms both Poisson model and stress release model. Monte Carlo simulation shows that the simulated seismicity by USRM is very close to the real seismicity.

When does stress help or harm? The effects of stress controllability and subjective stress response on Stroop performance.

Directory of Open Access Journals (Sweden)

Roselinde Kaiser Henderson

2012-06-01

Full Text Available The ability to engage in goal-directed behavior despite exposure to stress is critical to resilience. Questions of how stress can impair or improve behavioral functioning are important in diverse settings, from athletic competitions to academic testing to clinical therapy. Previous research suggests that controllability is a key factor in the impact of stress on behavior: learning how to control stressors buffers people from the negative effects of stress on subsequent cognitively demanding tasks. In addition, research suggests that the impact of stress on cognitive functioning depends on an individual’s response to stressors: moderate responses to stress can lead to improved performance while extreme (high or low responses can lead to impaired performance. The present studies tested the hypothesis that 1 learning to behaviorally control stressors leads to improved performance on a test of general executive functioning, the color-word Stroop, and that 2 this improvement emerges specifically for people who report moderate (subjective responses to stress. Experiment 1: Stroop performance, measured before and after a stress manipulation, was compared across groups of undergraduate participants (n=109. People who learned to control a noise stressor and received accurate performance feedback demonstrated reduced Stroop interference compared with people exposed to uncontrollable noise stress and feedback indicating an exaggerated rate of failure. In the group who learned behavioral control, those who reported moderate levels of stress showed the greatest reduction in Stroop interference. In contrast, in the group exposed to uncontrollable events, self-reported stress failed to predict performance. Experiment 2: In a second sample (n=90, we specifically investigated the role of controllability by keeping the rate of failure feedback constant across groups. In the group who learned behavioral control, those who reported moderate levels of stress

Green exercise as a workplace intervention to reduce job stress. Results from a pilot study.

Science.gov (United States)

Calogiuri, Giovanna; Evensen, Katinka; Weydahl, Andi; Andersson, Kim; Patil, Grete; Ihlebæk, Camilla; Raanaas, Ruth K

2015-01-01

Stress and mental fatigue are major health threats to employees in office-based occupations. Physical activity is widely used as a stress-management intervention for employees. Moreover, experiences in contact with nature have been shown to provide stress-reduction and restoration from mental fatigue. In a pilot study designed as a randomized controlled trial we investigated the impact of a green-exercise intervention on psychological and physiological indicators of stress in municipality employees. Fourteen employees (7 females and 7 males, 49±8 yrs) volunteered in an exercise-based intervention in workplace either outdoors in a green/nature area or in an indoor exercise-setting. The intervention consisted of an information meeting and two exercise sessions, each including a biking bout and a circuit-strength sequence using elastic rubber bands (45-minutes, at about 55% of HR reserve, overall). Main outcomes were perceived environmental potential for restoration, affective state, blood pressure (BP) and cortisol awakening response (CAR AUC(G) and CAR AUC(I)) and cortisol levels in serum. Measurements were taken at baseline and in concomitance with the exercise sessions. Furthermore, affective state and self-reported physical activity levels were measured over a 10-weeks follow-up period. Compared with the indoor group, the nature group reported higher environmental potential for restoration (p <  0.001) and Positive Affect (p <  0.01), along with improved CAR AUC(I) (p = 0.04) and, marginally, diastolic BP (p = 0.05). The nature group also reported higher ratings of Positive Affect at follow-up (p = 0.02). Differences at post-exercise were not found for any of the other components of affective state, systolic BP, CAR AUC(G) and cortisol levels measured in serum. Green-exercise at the workplace could be a profitable way to manage stress and induce restoration among employees. Further studies on larger samples are needed in order to improve the

The Effect of Boric Acid and Borax on Oxidative Stress, Inflammation, ER Stress and Apoptosis in Cisplatin Toxication and Nephrotoxicity Developing as a Result of Toxication.

Science.gov (United States)

Hazman, Ömer; Bozkurt, Mehmet Fatih; Fidan, Abdurrahman Fatih; Uysal, Fadime Erkan; Çelik, Sefa

2018-03-02

The development of treatment protocols that can reduce side effects in chemotherapy applications is extremely important in terms of cancer treatment. In this context, it was aimed to investigate the effects of boric acid and borax on cisplatin toxicity (nephrotoxicity) in rats. In the experimental phase, eight groups were formed from rats. Boric acid and borax were given to the treatment groups with three different doses using gavage. On the fifth day of the study, cisplatin (10 mg/kg) was administered to all rats except the control group. At the end of the study, oxidative stress-related (GSH, MDA, PCO, GPx, 8-OHdG), inflammation-related (TNF-α, IL-1β, IL-18, MCP-1, ICAM, TGF-β), apoptosis-related (p53, caspase 1, 3, 8, 12, bcl-2, bcl-xL, NFkB), and ER stress-related (GRP78, ATF-6, PERK) basic parameters were analyzed in serum, erythrocyte, and kidney tissues. Kidney tissues were also examined by histopathological and immunohistochemical methods. Borax and boric acid at different doses decreased inflammation and oxidative stress caused by cisplatin toxicity and increased ER stress. As a result of the treatments applied to experimental animals, it was determined that boric acid and borax reduced apoptotic damage in kidney tissue, but the decrease was statistically significant only in 200 mg/kg boric acid-administered group. In the study, low anti-apoptotic effects of borate doses with the anti-inflammatory and antioxidant effect may be due to increased ER stress at the relevant doses. Further studies on the effects of boron compounds on ER stress and apoptotic mechanisms may clarify this issue. Thus, possible side effects or if there are new usage areas of borone compounds which have many usage areas in clinics can be detected.

Failure of Sierra White granite under general states of stress

Science.gov (United States)

Ingraham, M. D.; Dewers, T. A.; Lee, M.; Holdman, O.; Cheung, C.; Haimson, B. C.

2017-12-01

The effect of the intermediate principal stress on the failure of Sierra White granite was investigated by performing tests under true triaxial states of stress. Tests were performed under constant Lode angle conditions with Lode angles ranging from 0 to 30°, pure shear to axisymmetric compression. Results show that the failure of Sierra White granite is heavily dependent on the intermediate principal stress which became more dramatic as the mean stress increased. An analysis of the shear bands formed at failure was performed using an associated flow rule and the Rudnicki and Rice (1975) localization criteria. The localization analysis showed excellent agreement with experimental results. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc. for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA0003525.

On the Stress Transfer of Nanoscale Interlayer with Surface Effects

Directory of Open Access Journals (Sweden)

Quan Yuan

2018-01-01

Full Text Available An improved shear-lag model is proposed to investigate the mechanism through which the surface effect influences the stress transfer of multilayered structures. The surface effect of the interlayer is characterized in terms of interfacial stress and surface elasticity by using Gurtin–Murdoch elasticity theory. Our calculation result shows that the surface effect influences the efficiency of stress transfer. The surface effect is enhanced with decreasing interlayer thickness and elastic modulus. Nonuniform and large residual surface stress distribution amplifies the influence of the surface effect on stress concentration.

Post-traumatic Stress Disorder Post Partum

Science.gov (United States)

Schwab, W.; Marth, C.; Bergant, A. M.

2012-01-01

Traumatic birth experiences may lead to serious psychological impairment. Recent studies show that a considerable number of women can develop post-traumatic stress disorder (PTSD), in some cases in a subsyndromal form. Until now, the possibility that postpartum psychological symptoms might be a continuum of a pre-existing disorder in pregnancy has rarely been considered. This study therefore aimed to evaluate the proportion of women who develop post-traumatic stress disorder as a result of childbirth. Materials and Methods: 56 multiparous women were recruited for the study. The diagnosis of PTSD was made according to the criteria for psychological disorders in the DSM-IV (Diagnostics and Statistical Manual of Mental Disorders). The data were collected in structured interviews in the 30th to 38th week of gestation and in the 6th week post partum. Results: Of the 56 women participating, 52 (93 %) completed the survey. Uncontrolled results showed that 21.15 % of the multiparous women met the full diagnostic PTSD criteria in the 6th week post partum. After the exclusion of all cases already characterised by all criteria or a subsyndromal form of PTSD caused by previous traumatisation, the PTSD rate was below 8 % at 6 weeks postpartum (= incidence rate of PTSD post partum). Conclusions: The present study is the first prospective longitudinal study to demonstrate the occurrence of full criteria PTSD in multiparous women as a result of childbirth after having excluded pre-existing PTSD. The results of our study show a high prevalence rate of PTSD during pregnancy. A number of women report all aspects of post-traumatic stress disorder as a result of childbirth. PMID:25253905

[Stress and job satisfaction in the discipline of inpatient anesthesiology : results of a web-based survey].

Science.gov (United States)

Bauer, J; Groneberg, D A

2014-01-01

��% in the respondents under 35 years old to 50.7 % in those 35-59 years old (OR: 1.79, 95 %-CI: 1.38-2.32). Looking at the different functional positions in the hospital, senior doctors showed a much higher prevalence of distress (52.8 %) than junior doctors (OR: 1.57, 95 %-CI: 1.21-2.05). Analyzing job satisfaction with respect to the functional position, the highest significant proportion was shown by senior doctors (65.8 %). This study revealed a high prevalence of unfavorable working conditions for anesthetists in hospitals. Taking the forthcoming shortage of qualified physicians in German hospitals into account, these results have to be considered as a cause for concern. Constant unfavorable working conditions have a negative effect on the mental and physical health of employees. Sooner or later a migration of qualified physicians abroad could be the consequence. To prevent a future shortage of qualified physicians and to make the hospital work place more appealing, working conditions have to be adapted to current needs and expectations of employees. The focus should be put on balanced working conditions according to stress models shown in this study.

Inserting Stress Analysis of Combined Hexagonal Aluminum Honeycombs

Directory of Open Access Journals (Sweden)

Xiangcheng Li

2016-01-01

Full Text Available Two kinds of hexagonal aluminum honeycombs are tested to study their out-of-plane crushing behavior. In the tests, honeycomb samples, including single hexagonal aluminum honeycomb (SHAH samples and two stack-up combined hexagonal aluminum honeycombs (CHAH samples, are compressed at a fixed quasistatic loading rate. The results show that the inserting process of CHAH can erase the initial peak stress that occurred in SHAH. Meanwhile, energy-absorbing property of combined honeycomb samples is more beneficial than the one of single honeycomb sample with the same thickness if the two types of honeycomb samples are completely crushed. Then, the applicability of the existing theoretical model for single hexagonal honeycomb is discussed, and an area equivalent method is proposed to calculate the crushing stress for nearly regular hexagonal honeycombs. Furthermore, a semiempirical formula is proposed to calculate the inserting plateau stress of two stack-up CHAH, in which structural parameters and mechanics properties of base material are concerned. The results show that the predicted stresses of three kinds of two stack-up combined honeycombs are in good agreement with the experimental data. Based on this study, stress-displacement curve of aluminum honeycombs can be designed in detail, which is very beneficial to optimize the energy-absorbing structures in engineering fields.

Yield stress independent column buckling curves

DEFF Research Database (Denmark)

Stan, Tudor‐Cristian; Jönsson, Jeppe

2017-01-01

of the yield stress is to some inadequate degree taken into account in the Eurocode by specifying that steel grades of S460 and higher all belong to a common set of “raised” buckling curves. This is not satisfying as it can be shown theoretically that the current Eurocode formulation misses an epsilon factor......Using GMNIA and shell finite element modelling of steel columns it is ascertained that the buckling curves for given imperfections and residual stresses are not only dependent on the relative slenderness ratio and the cross section shape but also on the magnitude of the yield stress. The influence...... in the definition of the normalised imperfection magnitudes. By introducing this factor it seems that the GMNIA analysis and knowledge of the independency of residual stress levels on the yield stress can be brought together and give results showing consistency between numerical modelling and a simple modified...

Smartphone Applications Utilizing Biofeedback Can Aid Stress Reduction

Science.gov (United States)

Dillon, Alison; Kelly, Mark; Robertson, Ian H.; Robertson, Deirdre A.

2016-01-01

Introduction: Stress is one of the leading global causes of disease and premature mortality. Despite this, interventions aimed at reducing stress have low adherence rates. The proliferation of mobile phone devices along with gaming-style applications allows for a unique opportunity to broaden the reach and appeal of stress-reduction interventions in modern society. We assessed the effectiveness of two smartphone applications games combined with biofeedback in reducing stress. Methods: We compared a control game to gaming-style smartphone applications combined with a skin conductance biofeedback device (the Pip). Fifty participants aged between 18 and 35 completed the Trier Social Stress Test. They were then randomly assigned to the intervention (biofeedback game) or control group (a non-biofeedback game) for thirty minutes. Perceived stress, heart rate and mood were measured before and after participants had played the games. Results: A mixed factorial ANOVA showed a significant interaction between time and game type in predicting perceived stress [F(1,48) = 14.19, p biofeedback intervention had significantly reduced stress compared to the control group. There was also a significant interaction between time and game in predicting heart rate [F(1,48) = 6.41, p biofeedback intervention showed significant reductions in heart rate compared to the control group. Discussion: This illustrates the potential for gaming-style smartphone applications combined with biofeedback as stress reduction interventions. PMID:27378963

CLASSICAL MUSIC DECREASE STRESS LEVEL AND BLOOD PRESSURE PRIMIGRAVIDA IN THE THIRD TRIMESTER

Directory of Open Access Journals (Sweden)

Ni Ketut Alit Armini

2017-07-01

Full Text Available Introduction: Many changes in psychology and biology increase primigravida’s stress in the third trimester. The stress response makes blood pressure being unstable, it causes bad effect for pregnancy. Classical music can be used as one of relaxation facilities that can reduce stress. The aimed of this study were to analyze the effect of classical music on stress level and blood pressure. Method: This study was used a quasy experimental purposive sampling design. The sample in this study were 14 pregnancy women in the third trimester in RSIA Cempaka Putih Permata Surabaya. The independent variable in this study was classical music and the dependent variable were stress level and blood pressure. Data were analyzed by Wilcoxon Signed Rank Test, Mann Withney U Test, Paired t Test and Independent t Test with significance level α≤0.05. Result: The result showed that the stress level in controlled group with p=0.567 and intervention group with p=0.025. The result of blood pressure in controlled group with p=0.522 in systolic blood pressure, p=0.35 in diastolic blood pressure and intervention group showed p=0.103 in systolic blood pressure and p=1.00 in diastolic blood pressure. Discussion: It can be concluded that listening classical music can reduce stress level, stabilize blood pressure, although blood pressure hasn’t significant result but mean of blood pressure show that it was stable. Further studies should be considered to used cortisol to identify stress biology response spesifically.

Heart rate response to post-learning stress predicts memory consolidation.

Science.gov (United States)

Larra, Mauro F; Schulz, André; Schilling, Thomas M; Ferreira de Sá, Diana S; Best, Daniel; Kozik, Bartlomiej; Schächinger, Hartmut

2014-03-01

Stressful experiences are often well remembered, an effect that has been explained by beta-adrenergic influences on memory consolidation. Here, we studied the impact of stress induced heart rate (HR) responses on memory consolidation in a post-learning stress paradigm. 206 male and female participants saw 52 happy and angry faces immediately before being exposed to the Cold Pressor Test or a non-stressful control procedure. Memory for the faces and their respective expression was tested twice, after 30 min and on the next day. High HR responders (in comparison to low HR responders as well as to the non-stressful control group) showed enhanced recognition memory one day after learning. Our results show that beta-adrenergic activation elicited shortly after learning enhances memory consolidation and that the stress induced HR response is a predictor for this effect. Copyright © 2013 Elsevier Inc. All rights reserved.

Resilience Training for Work-related Stress Among Health Care Workers: Results of a Randomized Clinical Trial Comparing In-person and Smartphone-delivered Interventions.

Science.gov (United States)

Mistretta, Erin G; Davis, Mary C; Temkit, M'hamed; Lorenz, Christopher; Darby, Betty; Stonnington, Cynthia M

2018-01-24

The aim of this study was to assess whether an in-person mindfulness-based resilience training (MBRT) program or a smartphone-delivered resiliency-based intervention improved stress, well-being, and burnout in employees at a major tertiary health care institution. Sixty participants were randomized to a 6-week MBRT, a resiliency-based smartphone intervention, or an active control group. Stress, well-being, and burnout were assessed at baseline, at program completion, and 3 months postintervention. Both the MBRT and the smartphone groups showed improvements in well-being, whereas only the MBRT group showed improvements in stress and emotional burnout over time. The control group did not demonstrate sustained improvement on any outcome. Findings suggest that brief, targeted interventions improve psychological outcomes and point to the need for larger scale studies comparing the individual and combined treatments that can inform development of tailored, effective, and low-cost programs for health care workers.

Determination of three-dimensional stress orientations in the Wenchuan earthquake Fault Scientific Drilling (WFSD) hole-1: A preliminary result by anelastic strain recovery measurements of core samples

Science.gov (United States)

Cui, J.; Lin, W.; Wang, L.; Tang, Z.; Sun, D.; Gao, L.; Wang, W.

2010-12-01

A great and destructive earthquake (Ms 8.0; Mw 7.9), Wunchuan earthquake struck on the Longmen Shan foreland trust zone in Sichuan province, China on 12 May 2008 (Xu et al., 2008; Episodes, Vol.31, pp.291-301). As a rapid response scientific drilling project, Wenchuan earthquake Fault Scientific Drilling (WFSD) started on 6 November 2008 shorter than a half of year from the date of earthquake main shock. The first pilot borehole (hole-1) has been drilled to the target depth (measured depth 1201 m MD, vertical depth 1179 m) at Hongkou, Dujianyan, Sichuan and passed through the main fault of the earthquake around 589 m MD. We are trying to determine three dimensional in-situ stress states in the WFSD boreholes by a core-based method, anelastic strain recovery (ASR) method (Lin et al., 2006; Tectonophysics, Vol4.26, pp.221-238). This method has been applied in several scientific drilling projects (TCDP: Lin et al., 2007; TAO, Vol.18, pp.379-393; NanTtoSEIZE: Byrne et al., 2009; GRL, Vol.36, L23310). These applications confirm the validity of using the ASR technique in determining in situ stresses by using drilled cores. We collected total 15 core samples in a depth range from 340 m MD to 1180 m MD, approximately for ASR measurements. Anelastic normal strains, measured every ten minutes in nine directions, including six independent directions, were used to calculate the anelastic strain tensors. The data of the ASR tests conducted at hole-1 is still undergoing analysis. As a tentative perspective, more than 10 core samples showed coherent strain recovery over one - two weeks. However, 2 or 3 core samples cannot be re-orientated to the global system. It means that we cannot rink the stress orientation determined by the core samples to geological structure. Unfortunately, a few core samples showed irregular strain recovery and were not analyzed further. The preliminary results of ASR tests at hole-1 show the stress orientations and stress regime changes a lot with the

Stress in the zoo: Tracking the impact of stress on memory formation over time.

Science.gov (United States)

Vogel, Susanne; Schwabe, Lars

2016-09-01

Although stress is well known to modulate human memory, precisely how memory formation is altered by a stressful encounter remains unclear. Stress effects on cognition are mainly mediated by the rapidly acting sympathetic nervous system, resulting in the release of catecholamines, and the slower acting hypothalamus-pituitary-adrenal axis secreting cortisol, which induces its effects on cognition through fast, non-genomic actions and delayed, genomic actions. Importantly, these different waves of the physiological stress response are thought to dynamically alter neural processing in brain regions important for memory such as the amygdala and the hippocampus. However, the precise time course of stress effects on memory formation is still unclear. To track the development of stress effects on memory over time, we tested individuals who underwent a stressful experience or a control procedure before a 2-h walk through a zoo, while an automatic camera continuously photographed the events they encoded. In a recognition memory test one week later, participants were presented with target photographs of their own zoo tour and lure photographs from an alternate tour. Stressed participants showed better memory for the experimental treatment than control participants, and this memory enhancement for the stressful encounter itself was directly linked to the sympathetic stress response. Moreover, stress enhanced memory for events encoded 41-65min after stressor onset, which was associated with the cortisol stress response, most likely arising from non-genomic cortisol actions. However, memory for events encoded long after the stressor, when genomic cortisol actions had most likely developed, remained unchanged. Our findings provide novel insights into how stress effects on memory formation develop over time, depending on the activity of major physiological stress response systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

Assessment of possibility of primary water stress corrosion cracking occurrence based on residual stress analysis in pressurizer safety nozzle of nuclear power plant

International Nuclear Information System (INIS)

Lee, Kyoung Soo; Kim, W.; Lee, Jeong Geun

2012-01-01

Primary water stress corrosion cracking (PWSCC) is a major safety concern in the nuclear power industry worldwide. PWSCC is known to initiate only in the condition in which sufficiently high tensile stress is applied to alloy 600 tube material or alloy 82/182 weld material in pressurized water reactor operating environments. However, it is still uncertain how much tensile stress is required to generate PWSCC or what causes such high tensile stress. This study was performed to predict the magnitude of weld residual stress and operating stress and compare it with previous experimental results for PWSCC initiation. For the study, a pressurizer safety nozzle was selected because it is reported to be vulnerable to PWSCC in overseas plants. The assessment was conducted by numerical analysis. Before performing stress analysis for plant conditions, a preliminary mock-up analysis was done. The result of the preliminary analysis was validated by residual stress measurement in the mockup. After verification of the analysis methodology, an analysis under plant conditions was conducted. The analysis results show that the stress level is not high enough to initiate PWSCC. If a plant is properly welded and operated, PWSCC is not likely to occur in the pressurizer safety nozzle.

In stressful company – Changes in stress and work ties over time

DEFF Research Database (Denmark)

Waldstrøm, Christian; Parker, Andrew; Shah, Neha P.

Recent research on stress and burnout has highlighted the collective aspects of stress symptoms, perceived stress, and coping mechanisms. Much of this work, however, is focused on group and team dynamics rather than how network factors shape individuals’ feelings of stress and burnout. We use...... a stress questionnaire and social network analysis at three time points in a Scandinavian biotechnology company to examine the interactions between stress and relationship development and maintenance over time. We show that individuals tend to form and maintain ties to people who are less stressed than...... they are, indicating that while misery might love company, stress does not. Given the longitudinal nature of the study, we’re able to disentangle the causal effects....

Lateral stress-induced propagation characteristics in photonic crystal fibres

Institute of Scientific and Technical Information of China (English)

Tian Hong-Da; Yu Zhong-Yuan; Han Li-Hong; Liu Yu-Min

2009-01-01

Using the finite element method, this paper investigates lateral stress-induced propagation characteristics in a pho-tonic crystal fibre of hexagonal symmetry. The results of simulation show the strong stress dependence of effective index of the fundamental guided mode, phase modal birefringence and confinement loss. It also finds that the contribution of the geometrical effect that is related only to deformation of the photonic crystal fibre and the stress-related contribution to phase modal birefringence and confinement loss are entirely different. Furthermore, polarization-dependent stress sensitivity of confinement loss is proposed in this paper.

Transgenerational transmission of a stress-coping phenotype programmed by early-life stress in the Japanese quail

Science.gov (United States)

Zimmer, Cédric; Larriva, Maria; Boogert, Neeltje J.; Spencer, Karen A.

2017-01-01

An interesting aspect of developmental programming is the existence of transgenerational effects that influence offspring characteristics and performance later in life. These transgenerational effects have been hypothesized to allow individuals to cope better with predictable environmental fluctuations and thus facilitate adaptation to changing environments. Here, we test for the first time how early-life stress drives developmental programming and transgenerational effects of maternal exposure to early-life stress on several phenotypic traits in their offspring in a functionally relevant context using a fully factorial design. We manipulated pre- and/or post-natal stress in both Japanese quail mothers and offspring and examined the consequences for several stress-related traits in the offspring generation. We show that pre-natal stress experienced by the mother did not simply affect offspring phenotype but resulted in the inheritance of the same stress-coping traits in the offspring across all phenotypic levels that we investigated, shaping neuroendocrine, physiological and behavioural traits. This may serve mothers to better prepare their offspring to cope with later environments where the same stressors are experienced. PMID:28387355

Revisions and further developments of the occupational stress indicator: Lisrel results from four dutch studies.

NARCIS (Netherlands)

Evers, A.; Frese, M.; Cooper, C.L.

2000-01-01

The Occupational Stress Indicator (OSI) is a popular instrument for the diagnosis of stress and stress-related personality and outcome variables. However, one weakness of the OSI was the low reliability of some of its scales. This paper describes in a series of 4 studies improvements of the

Subterranean stress engineering experiments

International Nuclear Information System (INIS)

Campbell, J.R.; Colgate, S.A.; Wheat, B.M.

1980-01-01

The state of stress in a subterranean rock mass has classically been assumed to be constant at best. In soil with a high clay content, preconsolidation and drainage methods can lead to more stable foundation material, but methods for engineering the stresses in large masses of rock are not well known. This paper shows the results from an experiment designed to alter the in situ rock stress field in an oil shale mine. This was done by hydrofracturing the rock by use of a packed-well injection system and then propping the crack open with a thixotropic gel, which slowly hardened to the consistency of cement. Successive hydrofracture and high-pressure grouting resulted in an overstressed region. Well-head injection pressures, surface tilts, injection rates, and subterranean strains were measured and recorded on floppy disk by a Z-80 microprocessor. The results were then transmitted to the large computer system at the Los Alamos Scientific Laboratory (LASL). To put the data in a more useful form, computer-generated movies of the tilts and strains were made by use of computer graphics developed at LASL. The purpose of this paper is to present results from the Single Large Instrumented Test conducted in the Colony Oil Shale Mine near Rifle, Colorado. 13 figures

Decreasing Stress and Burnout in Nurses: Efficacy of Blended Learning With Stress Management and Resilience Training Program.

Science.gov (United States)

Magtibay, Donna L; Chesak, Sherry S; Coughlin, Kevin; Sood, Amit

The study's purpose was to assess efficacy of blended learning to decrease stress and burnout among nurses through use of the Stress Management and Resiliency Training (SMART) program. Job-related stress in nurses leads to high rates of burnout, compromises patient care, and costs US healthcare organizations billions of dollars annually. Many mindfulness and resiliency programs are taught in a format that limits nurses' attendance. Consistent with blended learning, participants chose the format that met their learning styles and goals; Web-based, independent reading, facilitated discussions. The end points of mindfulness, resilience, anxiety, stress, happiness, and burnout were measured at baseline, postintervention, and 3-month follow-up to examine within-group differences. Findings showed statistically significant, clinically meaningful decreases in anxiety, stress, and burnout and increases in resilience, happiness, and mindfulness. Results support blended learning using SMART as a strategy to increase access to resiliency training for nursing staff.

[Work stress, health and satisfaction of life in young doctors. Results of a longitudinal study in Switzerland].

Science.gov (United States)

Buddeberg-Fischer, B; Stamm, M; Buddeberg, C; Bauer, G; Hämmig, O; Klaghofer, R

2008-11-01

Based on the Effort-Reward-Imbalance Model by Siegrist a study was undertaken to find out (a) in what way young doctors assess effort and reward during their specialist training; (b) whether there are certain job stress patterns over time; and (c) what the correlations are, if any, between perceived job stress, health and satisfaction with life. Within the framework of a prospective study (2001 - 2007) 370 doctors who had just qualified and were residents in the German-speaking part of Switzerland were assessed four times by means of anonymized questionnaires. Job stress, measured by the Effort-Reward-Imbalance scale, as well as health and satisfaction with life were assessed in these doctors' 2nd (T2), 4th (T3), and 6th (T4) year of specialist training ("residents"). Stress patterns of the participants were evaluated, based on the effort and reward scale values at T2, T3, and T4, by two-step cluster analysis. Gender differences between the clusters were calculated by the 2 test and differences in the continuous variables by analysis of variance with repeated measurements. During residency the percentage of doctors who experienced an Effort-Reward-Imbalance (ratio between effort and reward ERI > 1) increased from 18% at T2 to 20 % at T3 to 25 % at T4. The cluster analysis revealed two clusters: Type 1 (67%) with effort values below average and reward values above average (ER balance) across the three measurement points, and type 2 (33 %) with effort values above average and reward values below average (ER imbalance). Subjects in cluster 2 showed unfavorable values, when compared with those in cluster 1, in overcommitment, in workload and in the health variables (anxiety, depression, physical and psychological well-being), as well as in their assessed satisfaction with life at all three measurement points. One third of the doctors experienced stress at work, caused by an effort-reward imbalance. This had a negative impact on their health and satisfaction with life

Estimation of stress distribution in ferromagnetic tensile specimens using low cost eddy current stress measurement system and BP neural network.

Directory of Open Access Journals (Sweden)

Jianwei Li

Full Text Available Estimation of the stress distribution in ferromagnetic components is very important for evaluating the working status of mechanical equipment and implementing preventive maintenance. Eddy current testing technology is a promising method in this field because of its advantages of safety, no need of coupling agent, etc. In order to reduce the cost of eddy current stress measurement system, and obtain the stress distribution in ferromagnetic materials without scanning, a low cost eddy current stress measurement system based on Archimedes spiral planar coil was established, and a method based on BP neural network to obtain the stress distribution using the stress of several discrete test points was proposed. To verify the performance of the developed test system and the validity of the proposed method, experiment was implemented using structural steel (Q235 specimens. Standard curves of sensors at each test point were achieved, the calibrated data were used to establish the BP neural network model for approximating the stress variation on the specimen surface, and the stress distribution curve of the specimen was obtained by interpolating with the established model. The results show that there is a good linear relationship between the change of signal modulus and the stress in most elastic range of the specimen, and the established system can detect the change in stress with a theoretical average sensitivity of -0.4228 mV/MPa. The obtained stress distribution curve is well consonant with the theoretical analysis result. At last, possible causes and improving methods of problems appeared in the results were discussed. This research has important significance for reducing the cost of eddy current stress measurement system, and advancing the engineering application of eddy current stress testing.

Stress corrosion crack tip microstructure in nickel-based alloys

International Nuclear Information System (INIS)

Shei, S.A.; Yang, W.J.

1994-04-01

Stress corrosion cracking behavior of several nickel-base alloys in high temperature caustic environments has been evaluated. The crack tip and fracture surfaces were examined using Auger/ESCA and Analytical Electron Microscopy (AEM) to determine the near crack tip microstructure and microchemistry. Results showed formation of chromium-rich oxides at or near the crack tip and nickel-rich de-alloying layers away from the crack tip. The stress corrosion resistance of different nickel-base alloys in caustic may be explained by the preferential oxidation and dissolution of different alloying elements at the crack tip. Alloy 600 (UNS N06600) shows good general corrosion and intergranular attack resistance in caustic because of its high nickel content. Thermally treated Alloy 690 (UNS N06690) and Alloy 600 provide good stress corrosion cracking resistance because of high chromium contents along grain boundaries. Alloy 625 (UNS N06625) does not show as good stress corrosion cracking resistance as Alloy 690 or Alloy 600 because of its high molybdenum content

Macro design effects on stress distribution around implants: A photoelastic stress analysis

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Serhat Emre Ozkir

2012-01-01

Conclusion: As there were observable differences between the implant types, straight placed cylindrical implants showed better stress distribution characteristics, while inclined tapering implants had better stress distribution characteristics.

Micromagnetic modeling of the effects of stress on magnetic properties

International Nuclear Information System (INIS)

Zhu, B.; Lo, C. C. H.; Lee, S. J.; Jiles, D. C.

2001-01-01

A micromagnetic model has been developed for investigating the effect of stress on the magnetic properties of thin films. This effect has been implemented by including the magnetoelastic energy term into the Landau - Lifshitz - Gilbert equation. Magnetization curves of a nickel film were calculated under both tensile and compressive stresses of various magnitudes applied along the field direction. The modeling results show that coercivity increased with increasing compressive stress while remanence decreased with increasing tensile stress. The results are in agreement with the experimental data in the literature and can be interpreted in terms of the effects of the applied stress on the irreversible rotation of magnetic moments during magnetization reversal under an applied field. [copyright] 2001 American Institute of Physics

Stress reactivity and emotion in premenstrual syndrome

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Liu Q

2017-06-01

Full Text Available Qing Liu,1 Yongshun Wang,2 Cornelis Hermanus van Heck,3 Wei Qiao4 1Department of Nuclear Medicine and Medical PET Center, The Second Hospital of Zhejiang University School of Medicine, Zhejiang University, Hangzhou, 2School of Physical Education and Sport, Huaqiao University, Xiamen, People’s Republic of China; 3DCC, Donders Institute for Neuroscience and Neurocognition, Arnhem, the Netherlands; 4Department of Physical Education, Xiamen Institute of Technology, Xiamen, People’s Republic of China Background: Hormone level fluctuation across the menstrual cycle causes women to experience negative emotions and also affects their mood regulation and stress sensitivity. However, the stress reactivity and emotional variations in women with premenstrual syndrome (PMS, who are especially sensitive to the variations in hormone cycles, have not been explained. Methods: The present study used an electroencephalogram (EEG stress evaluation test, a physiology stress evaluation test, and the positive affect and negative affect scale (PANAS to evaluate the stress reactivity pattern and emotional state of women with PMS. Results: The results showed that women with PMS had higher negative affect and lower positive affect compared with controls. Moreover, under stressful conditions, the women with PMS had a higher alpha activity and a lower respiration rate than the controls. The differences in stress reactivity and emotional states between women with PMS and controls were based on a covariant analysis with menstrual cycle (luteal and follicular phases as the covariate. Conclusion: The results demonstrated that, compared with controls, women suffering from PMS have a continuous abnormality in emotional state and stress reactivity, which was independent of the menstrual cycle. Keywords: premenstrual syndrome, stress reactivity, emotion, EEG stress evaluation test, physiology stress evaluation test

Determining Factors for Stress Perception Assessed with the Perceived Stress Scale (PSS-4) in Spanish and Other European Samples.

Science.gov (United States)

Vallejo, Miguel A; Vallejo-Slocker, Laura; Fernández-Abascal, Enrique G; Mañanes, Guillermo

2018-01-01

Objective: Stress perception depends on cultural and social aspects that vary from one country to another. One of the most widely disseminated methods of assessing psychological stress is the Perceived Stress Scale (PSS-4). Therefore, in order to identify these factors and their impact on mental health, the present study compares the PSS-4 results among three European countries (Great Britain, France and Spain). This study focuses on PSS-4 results within a Spanish sample to determine: (1) normative data, reliability and validity of PSS-4 in a Spanish sample and (2) how stress perception changes depending on cultural and social factors. Methods: The data were obtained from a website representing a service of a smoking cessation program, the study represented a service that was open to all individuals. The number of participants were 37,451. They reported their age, gender, nationality, marital status, education and employment status, and completed two psychological questionnaires (PPS-4 and the anxiety and depression scales of the Symptom Checklist-90-Revised, SCL 90-R). Results: The PSS-4 scores could differentiate between relevant sociodemographic variables (such as sex, age, nationality, marital status, education, parental status, employment status, and income class). The PSS-4 scores showed a positive correlation with the SCL 90-R anxiety and depression scales. The normed values for interpreting the PSS-4 scores are presented. The PSS-4 showed adequate internal consistency and reliability. Conclusions: The PSS-4 is a useful instrument for assessing stress perception levels in the general population in different countries. Its internal consistency is sufficient for a 4-item scale.

Effectiveness of Mindfulness-Based Stress Reduction (MBSR In Stress and Fatigue in Patients with Multiple Sclerosis (MS

Directory of Open Access Journals (Sweden)

Ebrahimi Alisaleh

2016-07-01

Full Text Available Multiple sclerosis (MS disease can lead to creation of mental and behavioral disorders such as stress and fatigue. Controlling the problems in patients is essential. Hence, this study has considered effectiveness of mindfulnessbased stress reduction in stress and fatigue symptoms in patients with multiple sclerosis (MS.this study is in kind of semi-experimental research in form of pretest posttest pattern with control group. Statistical population of the study consists of all patients with multiple sclerosis referred to Iran MS Association by 2016. Sampling method in this study is available sampling and based on having inclusion criteria. among patients who gained point higher than 21.8 in stress inventory and point higher than 5.1 in fatigue inventory, 30 people are selected as sample randomly and are placed in 2 groups with 15 people in each group. The experimental group was placed under mindfulnessbased stress reduction (MBSR training course including 8 sessions with 2hrs per session. k\\however, no intervention was done in control group. All patients in experimental and control groups fulfilled stress and fatigue inventories before and after intervention. obtained data was analyzed using MANCOVA and in SPSS22 software. obtained results show that there is significant difference between the two groups in terms of stress and fatigue after intervention (p<0.001.according to obtained results, it could be found that treatment method of mindfulness-based stress reduction can help reduction of symptoms of stress and fatigue in patients with MS.

Sentence stress in children with dysarthria and cerebral palsy.

Science.gov (United States)

Kuschmann, Anja; Lowit, Anja

2018-03-08

This study aimed to advance our understanding of how children with dysarthria and cerebral palsy (CP) realise sentence stress acoustically, and how well listeners could identify the position of the stressed word within these utterances. Seven children with CP and eight typically developing children participated in the experiment. Stress on target words in two sentence positions was elicited through a picture-based question-answer paradigm. Acoustic parameters of stress [duration, intensity and fundamental frequency (F0)] were measured and compared between stressed and unstressed target words. For the perception experiment, ten listeners were asked to determine the position of the stressed word in the children's productions. Acoustic measures showed that at group level the typically developing children used all three acoustic parameters to mark sentence stress, whereas the children with CP showed changes in duration only. Individual performance variations were evident in both groups. Perceptually, listeners were significantly better at identifying the stressed words in the utterances produced by the typically developing children than those of the children with CP. The results suggest that children with CP can manipulate temporal speech properties to mark stress. This ability to modulate acoustic-prosodic features could be harnessed in intervention to enhance children's functional communication.

Zearalenone altered the cytoskeletal structure via ER stress- autophagy- oxidative stress pathway in mouse TM4 Sertoli cells.

Science.gov (United States)

Zheng, Wanglong; Wang, Bingjie; Si, Mengxue; Zou, Hui; Song, Ruilong; Gu, Jianhong; Yuan, Yan; Liu, Xuezhong; Zhu, Guoqiang; Bai, Jianfa; Bian, Jianchun; Liu, ZongPing

2018-02-20

The aim of this study was to investigate the molecular mechanisms of the destruction of cytoskeletal structure by Zearalenone (ZEA) in mouse-derived TM4 cells. In order to investigate the role of autophagy, oxidative stress and endoplasmic reticulum(ER) stress in the process of destruction of cytoskeletal structure, the effects of ZEA on the cell viability, cytoskeletal structure, autophagy, oxidative stress, ER stress, MAPK and PI3K- AKT- mTOR signaling pathways were studied. The data demonstrated that ZEA damaged the cytoskeletal structure through the induction of autophagy that leads to the alteration of cytoskeletal structure via elevated oxidative stress. Our results further showed that the autophagy was stimulated by ZEA through PI3K-AKT-mTOR and MAPK signaling pathways in TM4 cells. In addition, ZEA also induced the ER stress which was involved in the induction of the autophagy through inhibiting the ERK signal pathway to suppress the phosphorylation of mTOR. ER stress was involved in the damage of cytoskeletal structure through induction of autophagy by producing ROS. Taken together, this study revealed that ZEA altered the cytoskeletal structure via oxidative stress - autophagy- ER stress pathway in mouse TM4 Sertoli cells.

Association between changes in heart rate variability during the anticipation of a stressful situation and the stress-induced cortisol response.

Science.gov (United States)

Pulopulos, Matias M; Vanderhasselt, Marie-Anne; De Raedt, Rudi

2018-08-01

Vagal activity - reflecting the activation of stress regulatory mechanisms and prefrontal cortex activation - is thought to play an inhibitory role in the regulation of the hypothalamus-pituitary-adrenal axis. However, most studies investigating the association between stress-induced changes in heart rate variability (HRV, an index of cardiac vagal tone) and cortisol have shown a non-significant relationship. It has been proposed that physiological changes observed during anticipation of a stressor allow individuals to make behavioral, cognitive, and physiological adjustments that are necessary to deal with the upcoming actual stressor. In this study, in a large sample of 171 healthy adults (96 men and 75 women; mean age = 29.98, SD = 11.07), we investigated whether the cortisol response to a laboratory-based stress task was related to anticipation-induced or stress task-induced changes in HRV. As expected, regression analyses showed that a larger decrease in HRV during the anticipation of a stress task was related to higher stress task-induced cortisol increase, but not cortisol recovery. In line with prior research, the stress task-induced change in HRV was not significantly related to cortisol increase or recovery. Our results show for the first time that anticipatory HRV (reflecting differences in stress regulation and prefrontal activity before the encounter with the stressor) is important to understand the stress-induced cortisol increase. Copyright © 2018 Elsevier Ltd. All rights reserved.

The effect of stress on magnetic Barkhausen activity in ferromagnetic steels

International Nuclear Information System (INIS)

Jiles, D.C.

1989-01-01

This paper presents results of measurements of the effect of uniaxial tensile stresses of up to 85 MPa on Barkhausen activity and magnetic properties of AISI 4130 and AISI 4140 steels. The results showed that the location of maximum Barkhausen activity was very close to the coercive point. Barkhausen peak height and the total number of pulses were affected by the stress, although there was considerable scatter in some of the results so that it was not clear how the peak height of the AISI 4130 varied with stress

Residual stresses determination in an 8 mm Incoloy 800H weld via neutron diffraction

International Nuclear Information System (INIS)

Chen, Xizhang; Zhang, Shu Yan; Wang, Jingjun; Kelleher, Joe F.

2015-01-01

Highlights: • Stress through thickness at 5 mm from weld centerline indicates a “U” distribution. • Declining of tensile stress through thickness occurred at weld centerline. • Residual stress between layers is the lowest. - Abstract: To investigate the distribution of residual stresses, the 8 mm 800H alloy was joined by multi-layer butt TIG process. Residual stresses in the longitudinal, transverse and normal directions were measured via neutron diffraction. These residual stress measurements were taken at a series of points 2 mm below the top surface, covering the fusion zone, heat affected zone (HAZ) and base metal. In addition, two lines of longitudinal residual stress values at the weld centerline and 5 mm from weld centerline through thickness were measured. Results show that both the longitudinal and transverse stresses from the weld centerline to base metal are mainly tensile stresses. The longitudinal residual stress is the largest, with a maximum value of 330 MPa. As for the normal residual stress, the weld zone shows tensile stress, while the HAZ shows compressive stress. The middle of the thickness shows compressive residual stress along the thickness direction. The longitudinal stress at weld centerline through thickness reveals the interlayer heat treat effects leads to a declining of tensile stress. While the stress at 5 mm from weld centerline indicates a “U” distribution due to the mixed microstructure close to fusion line. With the increasing distance from weld seam, the residual stress decreases gradually

Physiological and Biochemical Responses in Two Ornamental Shrubs to Drought Stress.

Science.gov (United States)

Toscano, Stefania; Farieri, Elisa; Ferrante, Antonio; Romano, Daniela

2016-01-01

Drought stress is one of the most important abiotic stress limiting the plant survival and growth in the Mediterranean environment. In this work, two species typically grown in Mediterranean areas with different drought responses were used. Two shrubs, with slow (Photinia × fraseri Dress 'Red Robin') or fast (Eugenia uniflora L. 'Etna Fire') adaptation ability to drought, were subjected to three water regimes: well-watered (WW), moderate (MD), and severe (SD) drought stress conditions for 30 days. Net photosynthetic rate, stomatal conductance, maximum quantum efficiency of PSII photochemistry (Fv/Fm), relative water content (RWC), chlorophyll content, proline, malondialdehyde (MDA), and antioxidant enzyme activities (superoxide dismutase, catalase, and peroxidase) were measured. Results showed that RWC and proline were higher in Eugenia than in Photinia, demonstrating the greater tolerance of the latter to the water stress. The drought stress levels applied did not compromise photosynthetic efficiency through stomatal regulation, while a reduction of Fv/Fm ratio was observed at the end of the experimental period. MDA significantly increased after 30 days in both species. The antioxidant enzyme activities showed different responses to water stress conditions. In both species, the water stress scores showed positive, while proline content showed negative correlations with all physiological parameters.

The effect of stress and personality on dangerous driving behavior among Chinese drivers.

Science.gov (United States)

Ge, Yan; Qu, Weina; Jiang, Caihong; Du, Feng; Sun, Xianghong; Zhang, Kan

2014-12-01

The relationship between stress and road safety has been studied for many years, but the effect of global stress and its joint effect with personality on driving behavior have received little attention in previous studies. This study aimed to elucidate the impact of global stress and various personality traits on driving behavior. 242 drivers completed the Perceived Stress Scale-10 (PSS-10), the Dula Dangerous Driving Index (DDDI), and several personality trait scales related to anger, sensation seeking, and altruism. The results showed that perceived stress and sensation seeking were significantly correlated with the four subcategories of dangerous driving behavior, namely, negative cognitive/emotional driving (NCED), aggressive driving (AD), risky driving (RD), and drunk driving (DD). Moreover, anger was positively correlated with negative cognitive/emotional driving, aggressive driving, and risky driving, and altruism was negatively correlated with aggressive driving and drunk driving. Hierarchical multiple regressions were applied to analyze the mediating effect of personality traits, and the results showed that anger mediated the relationship between stress and dangerous driving behavior and that this mediating role was especially strong for negative cognitive/emotional driving and aggressive driving. Collectively, the results showed that stress is an important factor that can affect people's driving behavior but that personality traits mediate the effect of stress on driving behavior. The findings from this study regarding the relationship among stress, anger, and dangerous driving behavior could be applied in the development of intervention programs for stress and anger management in order to improve drivers' ability to manage emotional thoughts and adjust their behavior on the road. Copyright © 2014 Elsevier Ltd. All rights reserved.

Using the stress and adversity inventory as a teaching tool leads to significant learning gains in two courses on stress and health.

Science.gov (United States)

Slavich, George M; Toussaint, Loren

2014-10-01

The ability to measure cumulative stress exposure is important for research and teaching in stress and health, but until recently, no structured system has existed for assessing exposure to stress over the lifespan. Here, we report the results of two experimental studies that examined the pedagogical efficacy of using an automated system for assessing life stress, called the Stress and Adversity Inventory (STRAIN), for teaching courses on stress and health. In Study 1, a randomized, wait-list controlled experiment was conducted with 20 college students to test whether the STRAIN, coupled with a related lecture and discussion, promoted learning about stress and health. Results showed that this experiential lesson led to significant learning gains. To disentangle the effects of completing the STRAIN from participating in the lecture and discussion, we subsequently conducted Study 2 on 144 students using a 2 (STRAIN versus control activity) by 2 (STRAIN-specific lecture versus general stress lecture) repeated-measures design. Although the STRAIN-specific lecture was sufficient for promoting learning, completing the STRAIN also generated significant learning gains when paired with only the general stress lecture. Together, these studies suggest that the STRAIN is an effective tool for promoting experiential learning and teaching students about stress and health. Copyright © 2013 John Wiley & Sons, Ltd.

Responses of Early Lactating Ewes to Cold Stress Exposure Preliminary Results

Directory of Open Access Journals (Sweden)

Dinu Gavojdian

2012-10-01

Full Text Available The aim of this study was to measure cold stress of ewes during post lambing period. The trial was undertaken at theExperimental Farm of Banat’s University of Agricultural Sciences and Veterinary Medicine Timisoara, duringFebruary 2012. Six secundiparous Turcana breed ewes were housed in two collective pens of 3.5 m x 2 m each, withdeep straw bedding, in shed where the average temperature was of -1.2°C. Cortisol levels from milk samples weredetermined as indicators of cold stress. Samples were collected at 14 hours after lambing, and at 7, 14 and 21 daysfollowing parturition. At 14 hours after lambing, mean cortisol levels were 7.78±0.47 μg/dl, and decreased asfollows: 5.08±0.72 μg/dl in the 7th of the trial, 2.75±0.50 μg/dl in day 14 and 1.61±0.43 μg/dl in day 21 of theobservations. Differences were significant between the 7 day sampling intervals (p≤0.01 during the first 14 daysafter lambing, while non-significant differences (p≥0.05 have been found between the 14 and 21 days samplings. Ithas been concluded that cortisol levels in milk samples could prove an indicator of sheep adrenal-cortex activity thatmay be applied to measure cold stress in lactating ewes.

Residual Stress Testing of Outer 3013 Containers

International Nuclear Information System (INIS)

Dunn, K.

2004-01-01

A Gas Tungsten Arc Welded (GTAW) outer 3013 container and a laser welded outer 3013 container have been tested for residual stresses according to the American Society for Testing Materials (ASTM) Standard G-36-94 [1]. This ASTM standard describes a procedure for conducting stress-corrosion cracking tests in boiling magnesium chloride (MgCl2) solution. Container sections in both the as-fabricated condition as well as the closure welded condition were evaluated. Significantly large residual stresses were observed in the bottom half of the as-fabricated container, a result of the base to can fabrication weld because through wall cracks were observed perpendicular to the weld. This observation indicates that regardless of the closure weld technique, sufficient residual stresses exist in the as-fabricated container to provide the stress necessary for stress corrosion cracking of the container, at the base fabrication weld. Additionally, sufficiently high residual stresses were observed in both the lid and the body of the GTAW as well as the laser closure welded containers. The stresses are oriented perpendicular to the closure weld in both the container lid and the container body. Although the boiling MgCl2 test is not a quantitative test, a comparison of the test results from the closure welds shows that there are noticeably more through wall cracks in the laser closure welded container than in the GTAW closure welded container

Gender Differences in Rating Stressful Events, Depression, and Depressive Cognition.

Science.gov (United States)

Sowa, Claudia J.; Lustman, Patrick J.

1984-01-01

Administered the Life Stress Questionnaire, the Beck Depression Inventory, and the Automatic Thought Questionnaire to 140 students. Results showed significant sex differences. Men reported more stressful life change, but women rated the impact of stressors more severely and had higher depression. Men exhibited greater distortions in cognitive…

COPING WITH AND MANAGING STRESS STYLES OF FRESHMEN PHYSICAL EDUCATION STUDENTS AT THE PE FACULTY IN NIS

Directory of Open Access Journals (Sweden)

Danica Pirsl

2005-05-01

Full Text Available Stress is frequently viewed as an enemy. This is a misconception. Stress is often neither positive nor negative. Selye referred to stress judged as "good" as eustress. Distress, on the other hand, is stress that results in negative responses. Unchecked negative stress can interfere with the physiological and psychological functioning of the body and may ultimately result in disease or disability. A stressor is any physical, psychological or environmental event, or condition that initiates the stress. The body responds with the same threestage process. This series of changes is known as the general adaptation syndrome (GAS. The three phases are alarm, resistance, and exhaustion. It is interesting to note that PE students form their own stress copying styles in the mental, emotional and physical areas. Results are enhanced activities, sense of control and high energy level. Both male and female students show similar patterns of behaviour in stressful situations but female students show more interest in sporting activities when in stress-related situation

A proposed residual stress model for oblique turning

International Nuclear Information System (INIS)

Elkhabeery, M. M.

2001-01-01

A proposed mathematical model is presented for predicting the residual stresses caused by turning. Effects of change in tool free length, cutting speed, feed rate, and the tensile strength of work piece material on the maximum residual stress are investigated. The residual stress distribution in the surface region due to turning under unlubricated condition is determined using a deflection etching technique. To reduce the number of experiments required and build the mathematical model for these variables, Response Surface Methodology (RSM) is used. In addition, variance analysis and an experimental check are conducted to determine the prominent parameters and the adequacy of the model. The results show that the tensile stress of the work piece material, cutting speed, and feed rate have significant effects on the maximum residual stresses. The proposed model, that offering good correlation between the experimental and predicted results, is useful in selecting suitable cutting parameters for the machining of different materials. (author)

Stress corrosion cracking lifetime prediction of spring screw

International Nuclear Information System (INIS)

Koh, S. K.; Ryu, C. H.

2004-01-01

A lifetime prediction of holddown spring screw in nuclear fuel assembly was performed using fracture mechanics approach. The spring screw was designed such that it was capable of sustaining the loads imposed by the initial tensile preload and operational loads. In order to investigate the cause of failure and to predict the stress corrosion cracking life of the screw, a stress analysis of the top nozzle spring assembly was done using finite element analysis. The elastic-plastic finite element analysis showed that the local stresses at the critical regions of head-shank fillet and thread root significantly exceeded than the yield strength of the screw material, resulting in local plastic deformation. Normalized stress intensity factors for PWSCC life prediction was proposed. Primary water stress corrosion cracking life of the Inconel 600 screw was predicted by using integration of the Scott model and resulted in 1.78 years, which was fairly close to the actual service life of the holddown spring screw

Modelling of thermal stress in vapor generator supports

International Nuclear Information System (INIS)

Halpert, S.; Vazquez, L.

1997-01-01

To assure safety and availability of a nuclear power plant components or equipment stress analysis are done. When thermal loads are involved it's necessary to know the temperature field of the component or equipment. This paper describes the structural analysis of a steam generator lug with thermal load including the model used for computer simulation and presents the evolution of the temperature profile, the stress intensity and principal stress during start up and shut down of a nuclear power reactor. Temperature field obtained from code calculation show good agreement with the experimental data while stress analysis results are in agreement with a preview estimation. (author) [es

X-ray diffraction analysis of residual stresses in alumina-chromium composites and comparison with numerical simulations

Energy Technology Data Exchange (ETDEWEB)

Geandier, G.; Weisbecker, P.; Denis, S.; Mocellin, A. [L.S.G.2M., UMR, CNRS/INPL, Ecole des Mines de Nancy, Nancy (France); Hazotte, A. [L.S.G.2M., UMR, CNRS/INPL, Ecole des Mines de Nancy, Nancy (France); LETAM, UMR, CNRS/Metz Univ., ISGMP, Metz (France); Lebrun, J.L. [L.P.M.I., ENSAM Angers, Angers (France); Elkaim, E. [L.U.R.E., Centre Univ. Paris-Sud, Orsay (France)

2002-07-01

Residual stresses in alumina chromium composites have been determined using X ray synchrotron diffraction at LURE. Results show that non-negligible residual stresses exist in the composites. Mean residual stresses calculated by finite element show discrepancies with experimental values that are discussed in relation with experimental difficulties and calculation assumptions. (orig.)

Mean stress effects on high-cycle fatigue of Alloy 718

International Nuclear Information System (INIS)

Korth, G.E.

1980-07-01

This report covers an investigation of the effects of tensile mean stress on the high-cycle fatigue properties of Alloy 718. Three test temperatures (24, 427, and 649 degree C) were employed, and there were tests in both strain and load control. Results were compared with three different models: linear Modified-Goodman, Peterson cubic, and stress-strain parameter. The linear Modified-Goodman model gave good correlation with actual test data for low and moderate mean stress values, but the stress-strain parameter showed excellent correlation over the entire range of possible mean stresses and therefore is recommended for predicting mean stress effects of Alloy 718. 13 refs., 12 figs

Sex differences in the stress response in SD rats.

Science.gov (United States)

Lu, Jing; Wu, Xue-Yan; Zhu, Qiong-Bin; Li, Jia; Shi, Li-Gen; Wu, Juan-Li; Zhang, Qi-Jun; Huang, Man-Li; Bao, Ai-Min

2015-05-01

Sex differences play an important role in depression, the basis of which is an excessive stress response. We aimed at revealing the neurobiological sex differences in the same study in acute- and chronically-stressed rats. Female Sprague-Dawley (SD) rats were randomly divided into 6 groups: chronic unpredictable mild stress (CUMS), acute foot shock (FS) and controls, animals in all 3 groups were sacrificed in proestrus or diestrus. Male SD rats were randomly divided into 3 groups: CUMS, FS and controls. Comparisons were made of behavioral changes in CUMS and control rats, plasma levels of corticosterone (CORT), testosterone (T) and estradiol (E2), and of the hypothalamic mRNA-expression of stress-related molecules, i.e. estrogen receptor α and β, androgen receptor, aromatase, mineralocorticoid receptor, glucocorticoid receptor, corticotropin-releasing hormone, arginine vasopressin and oxytocin. CUMS resulted in disordered estrus cycles, more behavioral and hypothalamic stress-related molecules changes and a stronger CORT response in female rats compared with male rats. Female rats also showed decreased E2 and T levels after FS and CUMS, while male FS rats showed increased E2 and male CUMS rats showed decreased T levels. Stress affects the behavioral, endocrine and the molecular response of the stress systems in the hypothalamus of SD rats in a clear sexual dimorphic way, which has parallels in human data on stress and depression. Copyright © 2015 Elsevier B.V. All rights reserved.

Stress induced anisotropy in CoFeMn soft magnetic nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Leary, A. M., E-mail: leary@cmu.edu; Keylin, V.; McHenry, M. E. [Materials Science and Engineering Department, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, Pennsylvania 15213 (United States); Ohodnicki, P. R. [Functional Materials Development Division, National Energy Technology Laboratory (NETL), 626 Cochrans Mill Road, Pittsburgh, Pennsylvania 15236 (United States)

2015-05-07

The use of processing techniques to create magnetic anisotropy in soft magnetic materials is a well-known method to control permeability and losses. In nanocomposite materials, field annealing below the Curie temperature results in uniaxial anisotropy energies up to ∼2 kJ/m{sup 3}. Higher anisotropies up to ∼10 kJ/m{sup 3} result after annealing Fe-Si compositions under stress due to residual stress in the amorphous matrix acting on body centered cubic crystals. This work describes near zero magnetostriction Co{sub 80−x−y}Fe{sub x}Mn{sub y}Nb{sub 4}B{sub 14}Si{sub 2} soft magnetic nanocomposites, where x and y < 8 at.% with close packed crystalline grains that show stress induced anisotropies up to ∼50 kJ/m{sup 3} and improved mechanical properties with respect to Fe-Si compositions. Difference patterns measured using transmission X-ray diffraction show evidence of affine strain with respect to the stress axis.

MONITORING ON PLANT LEAF WATER POTENTIAL USING NIR SPECTROSCOPY FOR WATER STRESS MANAGEMENT

Directory of Open Access Journals (Sweden)

Diding Suhandy

2012-12-01

Full Text Available The performance of the calibration model with temperature compensation for on-plant leaf water potential (LWP determination in tomato plants was evaluated. During a cycle of water stress, the on-plant LWP measurement was conducted. The result showed that the LWP values under water stress and recovery from water stress could be monitored well. It showed that a real time monitoring of the LWP values using NIR spectroscopy could be possible.   Keywords: water stress, real time monitoring of leaf water potential, NIR spectroscopy, plant response-based

Child anxiety symptoms related to longitudinal cortisol trajectories and acute stress responses: evidence of developmental stress sensitization.

Science.gov (United States)

Laurent, Heidemarie K; Gilliam, Kathryn S; Wright, Dorianne B; Fisher, Philip A

2015-02-01

Cross-sectional research suggests that individuals at risk for internalizing disorders show differential activation levels and/or dynamics of stress-sensitive physiological systems, possibly reflecting a process of stress sensitization. However, there is little longitudinal research to clarify how the development of these systems over time relates to activation during acute stress, and how aspects of such activation map onto internalizing symptoms. We investigated children's (n = 107) diurnal hypothalamic-pituitary-adrenal activity via salivary cortisol (morning and evening levels) across 29 assessments spanning 6+ years, and related longitudinal patterns to acute stress responses at the end of this period (age 9-10). Associations with child psychiatric symptoms at age 10 were also examined to determine internalizing risk profiles. Increasing morning cortisol levels across assessments predicted less of a cortisol decline following interpersonal stress at age 9, and higher cortisol levels during performance stress at age 10. These same profiles of high and/or sustained cortisol elevation during psychosocial stress were associated with child anxiety symptoms. Results suggest developmental sensitization to stress-reflected in rising morning cortisol and eventual hyperactivation during acute stress exposure-may distinguish children at risk for internalizing disorders. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

Occupational status and job stress in relation to cardiovascular stress reactivity in Japanese workers

Directory of Open Access Journals (Sweden)

Kumi Hirokawa

2016-12-01

Full Text Available This study aimed to investigate the effects of occupational status and job stress factors on cardiovascular stress reactivity in Japanese workers. In this baseline assessment between 2001 and 2009 in Osaka, Japan, we examined 928 healthy Japanese employees (330 men, 598 women from two occupational statuses: managers/professionals and general workers. A brief job stress questionnaire was used to evaluate job stress levels. Systolic and diastolic blood pressure (SBP, DBP, heart rate, heart rate variability (high-frequency [HF], low-frequency [LF], LF/HF], and peripheral blood flow were measured at rest and during two stressful tasks. Changes in stress reactivity were calculated as the difference between the measured variables during the tasks and the rest period. Men showed inverse associations between quantitative job overload and DBP, heart rate, and LF/HF, between physical demands and blood pressure (SBP, DBP, and between a poor physical environment and HF. Men also had positive associations between qualitative job overload and heart rate, and between physical demands and peripheral blood flow (all p < 0.05. Women showed inverse associations between qualitative job overload and SBP, and showed positive associations between qualitative job overload and peripheral blood flow, and between a poor physical environment and SBP (all p < 0.05. When stratified by occupational status, significant associations between job stress and changes in stress reactivity were observed in male managers/professionals and female general workers (p < 0.05. Job stress levels are associated with changes in cardiovascular stress reactivity in men and women. Occupational status may modify these associations.

Compassion satisfaction, compassion fatigue, anxiety, depression and stress in registered nurses in Australia: phase 2 results.

Science.gov (United States)

Drury, Vicki; Craigie, Mark; Francis, Karen; Aoun, Samar; Hegney, Desley G

2014-05-01

This is the first two-phase Australian study to explore the factors impacting upon compassion satisfaction, compassion fatigue, anxiety, depression and stress and to describe the strategies nurses use to build compassion satisfaction into their working lives. Compassion fatigue has been found to impact on job satisfaction, the quality of patient care and retention within nursing. This study provides new knowledge on the influences of anxiety, stress and depression and how they relate to compassion satisfaction and compassion fatigue. In Phase 2 of the study, 10 nurses from Phase 1 of the study participated in individual interviews and a focus group. A semi-structured interview schedule guided the conversations with the participants. Data analysis resulted in seven main themes: social networks and support;infrastructure and support; environment and lifestyle; learning; leadership; stress; and suggestions to build psychological wellness in nurses. Findings suggest that a nurse’s capacity to cope is enhanced through strong social and collegial support, infrastructure that supports the provision of quality nursing care and positive affirmation. These concepts are strongly linked to personal resilience. for nursing management These findings support the need for management to develop appropriate interventions to build resilience in nurses.

Glutamate neurotransmission is affected in prenatally stressed offspring

DEFF Research Database (Denmark)

Adrover, Ezequiela; Pallarés, Maria Eugenia; Baier, Carlos Javier

2015-01-01

Previous studies from our laboratory have shown that male adult offspring of stressed mothers exhibited higher levels of ionotropic and metabotropic glutamate receptors than control rats. These offspring also showed long-lasting astroglial hypertrophy and a reduced dendritic arborization with syn......Previous studies from our laboratory have shown that male adult offspring of stressed mothers exhibited higher levels of ionotropic and metabotropic glutamate receptors than control rats. These offspring also showed long-lasting astroglial hypertrophy and a reduced dendritic arborization...... with synaptic loss. Since metabolism of glutamate is dependent on interactions between neurons and surrounding astroglia, our results suggest that glutamate neurotransmitter pathways might be impaired in the brain of prenatally stressed rats. To study the effect of prenatal stress on the metabolism...... was not affected it was found that prenatal stress (PS) changed the expression of the transporters, thus, producing a higher level of vesicular vGluT-1 in the frontal cortex (FCx) and elevated levels of GLT1 protein and messenger RNA in the hippocampus (HPC) of adult male PS offspring. We also observed increased...

Occupational Stress

OpenAIRE

Löblová, Klára

2011-01-01

The thesis deals with load, stress and related questions of the working life. Work-related stress brings numerous difficulties not only to affected individuals, but as a result also to organizations. The thesis follows symptoms, impacts, somatic and mental aspects of stress, its types and also types of stressors, which cause this problem. It is concentrated on workload as a specific area of work-related stress, individual resistance to the load, factors of workload and work-related stress and...

Social stress in early adolescents' daily lives: Associations with affect and loneliness.

Science.gov (United States)

van Roekel, Eeske; Ha, Thao; Verhagen, Maaike; Kuntsche, Emmanuel; Scholte, Ron H J; Engels, Rutger C M E

2015-12-01

Adolescence is characterized by increased social stress due to changes in interpersonal relationships, but little is known about daily experiences of social stress. The aim of the present study was to examine daily life predictors of increases in social stress, how these increases affected adolescents' mood, and whether loneliness moderated these relations. The Experience Sampling Method was used to measure positive and negative affect and increases in social stress in 278 early adolescents from the Netherlands. Results showed that adolescents were most likely to experience increases in social stress when they were with classmates, during week days, and in the morning. Lonely adolescents showed higher increases in social stress and responded more negatively to increases in social stress, compared to non-lonely adolescents. Copyright © 2015 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

Generation of sheared poloidal flows via Reynolds stress and transport barrier physics

International Nuclear Information System (INIS)

Hidalgo, C.; Pedrosa, M.A.; Sanchez, E.; Balbin, R.; Lopez-Fraguas, A.; Milligen, B. van; Silva, C.; Fernandes, H.; Varandas, C.A.F.; Riccardi, C.; Carrozza, R.; Fontanesi, M.; Carreras, B.A.; Garcia, L.

2000-01-01

A view of the latest experimental results and progress in the understanding of the role of poloidal flows driven by fluctuations via Reynolds stress is given. Reynolds stress shows a radial gradient close to the velocity shear layer location in tokamaks and stellarators, indicating that this mechanism may drive significant poloidal flows in the plasma boundary. Observation of the generation of ExB sheared flows via Reynolds stress at the ion Bernstein resonance layer has been noticed in toroidal magnetized plasmas. The experimental evidence of sheared ExB flows linked to the location of rational surfaces in stellarator plasmas might be interpreted in terms of Reynolds stress sheared driven flows. These results show that ExB sheared flows driven by fluctuations can play an important role in the generation of transport barriers. (author)

Using aquatic fungi for pharmaceutical bioremediation: Uptake of acetaminophen by Mucor hiemalis does not result in an enzymatic oxidative stress response.

Science.gov (United States)

Esterhuizen-Londt, Maranda; Schwartz, Katrin; Pflugmacher, Stephan

2016-10-01

The increasing anthropogenic pollution of aquatic environments and fresh water scarcity worldwide have prompted the development of low-cost and effective water treatment alternatives. One example of a highly released anthropogenic xenobiotics is acetaminophen (APAP), which has been detected in surface waters at concentrations as high as 5 μg L(-1). To date, traditional water treatment plants were unable to remove all pharmaceutical xenobiotics and as in the case with APAP, the breakdown products are toxic. Phytoremediation has proved to remove xenobiotics efficiently producing no toxic breakdown products, however, they are often restrained in their application range. Therefore, it was necessary to find alternate remediation tools to extend and complement the application ranges of existing bioremediation techniques. With the success of mycoremediation as well as the adaptability of fungi, Mucor hiemalis was investigated in terms of its APAP uptake capabilities. The investigation included the examination of concentration- and time-dependent uptake studies to examine the effects of each of these parameters independently. Additionally, the extracellular peroxidase activity of M. hiemalis was measured with exposure to APAP to evaluate possible breakdown and the antioxidative stress enzymes, catalase, glutathione peroxidase, and glutathione reductase, were assayed to investigate whether APAP caused oxidative stress. The results showed that M. hiemalis was able to internalize between 1 and 2 μg APAP per g dried fungal biomass when exposed to 5, 10, 50 and 100 ng mL(-1) APAP for 24-48 h, but not beyond this time frame. Further, exposure to APAP did not result in elevated extracellular peroxidase activity or oxidative stress. The findings led to the conclusion that M. hiemalis could be integrated in bioremediation systems, for short-term degradation at low concentrations of APAP with effective management. Copyright © 2016 British Mycological Society. Published by

Contact mechanical analysis of O-ring stresses

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyung Kyu

2007-02-15

The purpose of this project is to develop the approximate solutions of contact traction and internal stress of an O-ring by using a two dimensional elasticity for enhancing the design and failure prediction technology. Investigated were the applicability of Lindley's formulae of contact force prediction and the Hertz theory. Three cases of O-ring installation were considered. The approximate solution of contact tractions and internal stresses of each case were derived. The key results are summarized as follows: 1. It is verified that Lindley's formulae predicts the relationship between the fractional compression and contact force. 2. In the case of Case I, II and III without internal pressure, it is found that a function form of the contact traction is the Hertzian. So it is possible to express the traction with a Hertzian form and correction factors. 3. The internal stresses are derived in the case of the Hertzian traction profile. The stresses at the center of O-ring show a satisfactory result when compared with the finite element result.

Effects of work stress and home stress on autonomic nervous function in Japanese male workers.

Science.gov (United States)

Maeda, Eri; Iwata, Toyoto; Murata, Katsuyuki

2015-01-01

Autonomic imbalance is one of the important pathways through which psychological stress contributes to cardiovascular diseases/sudden death. Although previous studies have focused mainly on stress at work (work stress), the association between autonomic function and stress at home (home stress) is still poorly understood. The purpose was to clarify the effect of work/home stress on autonomic function in 1,809 Japanese male workers. We measured corrected QT (QTc) interval and QT index on the electrocardiogram along with blood pressure and heart rate. Participants provided self-reported information about the presence/absence of work/home stress and the possible confounders affecting QT indicators. Home stress was related positively to QT index (p=0.040) after adjusting for the possible confounders, though work stress did not show a significant relation to QTc interval or QT index. The odds ratio of home stress to elevated QT index (≥105) was 2.677 (95% CI, 1.050 to 6.822). Work/home stress showed no significant relation to blood pressure or heart rate. These findings suggest that autonomic imbalance, readily assessed by QT indicators, can be induced by home stress in Japanese workers. Additional research is needed to identify different types of home stress that are strongly associated with autonomic imbalance.

[Nursery Teacher's Stress Scale (NTSS): reliability and validity].

Science.gov (United States)

Akada, Taro

2010-06-01

This study describes the development and evaluation of the Nursery Teacher's Stress Scale (NTSS), which explores the relation between daily hassles at work and work-related stress. In Analysis 1, 29 items were chosen to construct the NTSS. Six factors were identified: I. Stress relating to child care; II. Stress from human relations at work; III. Stress from staff-parent relations; IV. Stress from lack of time; V. Stress relating to compensation; and VI. Stress from the difference between individual beliefs and school policy. All these factors had high degrees of internal consistency. In Analysis 2, the concurrent validity of the NTSS was examined. The results showed that the NTSS total scores were significantly correlated with the Job Stress Scale-Revised Version (job stressor scale, r = .68), the Pre-school Teacher-efficacy Scale (r = -.21), and the WHO-five Well-Being Index Japanese Version (r = -.40). Work stresses are affected by several daily hassles at work. The NTSS has acceptable reliability and validity, and can be used to improve nursery teacher's mental health.

Surface Wave Velocity-Stress Relationship in Uniaxially Loaded Concrete

DEFF Research Database (Denmark)

Shokouhi, Parisa; Zoëga, Andreas; Wiggenhauser, Herbert

2012-01-01

The sonic surface wave (or Rayleigh wave) velocity measured on prismatic concrete specimens under uniaxial compression was found to be highly stress-dependent. At low stress levels, the acoustoelastic effect and the closure of existing microcracks results in a gradual increase in surface wave...... velocities. At higher stress levels, concrete suffers irrecoverable damage: the existing microcracks widen and coalesce and new microcracks form. This progressive damage process leads first to the flattening and eventually the drop in the velocity-stress curves. Measurements on specimens undergoing several...... loading cycles revealed that the velocities show a stress-memory effect in good agreement with the Kaiser effect. Comparing the velocities measured during loading and unloading, the effects of stress and damage on the measured velocities could be differentiated. Moreover, the stress dependency of surface...

Perceived stress and cause-specific mortality among men and women: results from a prospective cohort study

DEFF Research Database (Denmark)

Nielsen, Naja Rod; Kristensen, Tage S; Schnohr, Peter

2008-01-01

until 2004, with Sex differences were found in the relations between stress and mortality (p = 0.02). After adjustments, men with high stress versus low stress had higher all-cause mortality (hazard ratio (HR) = 1.32, 95% confidence interval (CI): 1.15, 1.52). This finding......The authors assessed the effect of psychological stress on total and cause-specific mortality among men and women. In 1981-1983, the 12,128 Danish participants in the Copenhagen City Heart Study were asked two questions on stress intensity and frequency and were followed in a nationwide registry...... was most pronounced for deaths due to respiratory diseases (high vs. low stress: HR = 1.79, 95% CI: 1.10, 2.91), external causes (HR = 3.07, 95% CI: 1.65, 5.71), and suicide (HR = 5.91, 95% CI: 2.47, 14.16). High stress was related to a 2.59 (95% CI: 1.20, 5.61) higher risk of ischemic heart disease...

Impact of new traumatic or stressful life events on pre-existing PTSD in traumatized refugees: results of a longitudinal study

Directory of Open Access Journals (Sweden)

Katrin Schock

2016-11-01

Full Text Available Background: A significant proportion of trauma survivors experience an additional critical life event in the aftermath. These renewed experiences of traumatic and stressful life events may lead to an increase in trauma-related mental health symptoms.Method: In a longitudinal study, the effects of renewed experiences of a trauma or stressful life event were examined. For this purpose, refugees seeking asylum in Germany were assessed for posttraumatic stress symptoms (PTS, Posttraumatic Stress Diagnostic Scale (PDS, anxiety, and depression (Hopkins Symptom Checklist [HSCL-25] before treatment start as well as after 6 and 12 months during treatment (N=46. Stressful life events and traumatic events were recorded monthly. If a new event happened, PDS and HSCL were additionally assessed directly afterwards. Mann–Whitney U-tests were performed to calculate the differences between the group that experienced an additional critical event (stressful vs. trauma during treatment (n=23 and the group that did not (n=23, as well as differences within the critical event group between the stressful life event group (n=13 and the trauma group (n=10.Results: Refugees improved significantly during the 12-month period of our study, but remained severely distressed. In a comparison of refugees with a new stressful life event or trauma, significant increases in PTS, anxiety, and depressive symptoms were found directly after the experience, compared to the group without a renewed event during the 12 months of treatment. With regard to the different critical life events (stressful vs. trauma, no significant differences were found regarding overall PTS, anxiety, and depression symptoms. Only avoidance symptoms increased significantly in the group experiencing a stressful life event.Conclusion: Although all clinicians should be aware of possible PTS symptom reactivation, especially those working with refugees and asylum seekers, who often experience new critical life

Ultrasonic evaluation of heat treatment for stress relief in steel

International Nuclear Information System (INIS)

Bittencourt, Marcelo de S.Q.; Lamy, Carlos A.; Goncalves Filho, Orlando J.A.; Payao Filho, Joao da C.

2000-01-01

Residual stresses in materials arise due to the manufacturing processes. As a consequence, in the nuclear area some components must suffer a stress relief treatment according to strict criteria. Although these treatments are carefully carried on, concern with nuclear safety is constantly growing. This work proposes a nondestructive ultrasonic method to guarantee the efficiency of the heat treatment. It was used a short peened steel plate with tensile and compressive stresses which was submitted to a stress relief treatment. The results show that the proposed ultrasonic method could be used to confirm the efficiency of the stress relief heat treatment. (author)

The fatigue behavior of composite laminates under various mean stresses

Science.gov (United States)

Rotem, A.

1991-01-01

A method is developed for predicting the S-N curve of a composite laminate which is subjected to an arbitrary stress ratio, R (minimum stress/maximum stress). The method is based on the measuring of the S-N behavior of two distinct cases, tension-tension and compression-compression fatigue loadings. Using these parameters, expressions are formulated that estimate the fatigue behavior under any stress ratio loading. Experimental results from the testing of graphite/epoxy laminates, with various structures, are compared with the predictions and show good agreement.

A study of occupational therapy students' stress coping in the term of clinical practice

OpenAIRE

立石, 恵子; 立石, 修康; タテイシ, ケイコ; タテイシ, ノブヤス; Keiko, TATEISHI; Nobuyasu, TATEISHI

2005-01-01

The purpose of this study is to investigate students' stress coping in the term of clinical practice. We ded questionnaire to 30 students after clinical practice. The result shows forty-six stress situations were observed. Most of the students felt the stress that the supervisor advied about general manners or behaviors. Such as communication with patients and clinical staffs, students personality, speaking volume. We categorized the stress coping strategies into two types. The result indicat...

A Piezoelectric Shear Stress Sensor

Science.gov (United States)

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

[Effect of opioid receptors on acute stress-induced changes in recognition memory].

Science.gov (United States)

Liu, Ying; Wu, Yu-Wei; Qian, Zhao-Qiang; Yan, Cai-Fang; Fan, Ka-Min; Xu, Jin-Hui; Li, Xiao; Liu, Zhi-Qiang

2016-12-25

Although ample evidence has shown that acute stress impairs memory, the influences of acute stress on different phases of memory, such as acquisition, consolidation and retrieval, are different. Experimental data from both human and animals support that endogenous opioid system plays a role in stress, as endogenous opioid release is increased and opioid receptors are activated during stress experience. On the other hand, endogenous opioid system mediates learning and memory. The aim of the present study was to investigate the effect of acute forced swimming stress on recognition memory of C57 mice and the role of opioid receptors in this process by using a three-day pattern of new object recognition task. The results showed that 15-min acute forced swimming damaged the retrieval of recognition memory, but had no effect on acquisition and consolidation of recognition memory. No significant change of object recognition memory was found in mice that were given naloxone, an opioid receptor antagonist, by intraperitoneal injection. But intraperitoneal injection of naloxone before forced swimming stress could inhibit the impairment of recognition memory retrieval caused by forced swimming stress. The results of real-time PCR showed that acute forced swimming decreased the μ opioid receptor mRNA levels in whole brain and hippocampus, while the injection of naloxone before stress could reverse this change. These results suggest that acute stress may impair recognition memory retrieval via opioid receptors.

Predictors of Familial Acculturative Stress in Asian American College Students

Science.gov (United States)

Castillo, Linda G.; Zahn, Marion P.; Cano, Miguel A.

2012-01-01

The authors examined the predictors of familial acculturative stress in 85 Asian American college students. Participants were primarily 1st- and 2nd-generation U.S. citizens. Results showed that perceived acculturative family conflict and family intragroup marginalization were related to higher levels of familial acculturative stress for…

Post-traumatic stress symptoms, parenting stress and mother-child relationships following childbirth and at 2 years postpartum.

Science.gov (United States)

McDonald, Sarah; Slade, Pauline; Spiby, Helen; Iles, Jane

2011-09-01

This study examined the prevalence of childbirth-related post-traumatic stress (PTS) symptoms at 2 years postpartum and the relationship between such symptoms and both self-reported parenting stress and perceptions of the mother-child relationship. 81 women completed measures of childbirth-related PTS symptoms at 6 weeks and 3 months postpartum; these results were used in an exploration of their predictive links with mother-child relationship and parenting measures at 2 years. 17.3% of respondents reported some PTS symptoms at a clinically significant level at 2 years postpartum. However, these symptoms were only weakly linked to parenting stress and were not related to mothers' perceptions of their children. However earlier PTS symptoms within 3 months of childbirth did show limited associations with parenting stress at 2 years but no association with child relationship outcomes once current depression was taken into account. Implications for clinical practice and the concept of childbirth-related post-traumatic stress disorder are discussed.

Decision-Making Competence, Social Orientation, Time Style, and Perceived Stress

Directory of Open Access Journals (Sweden)

Martin Geisler

2018-04-01

Full Text Available Peoples’ decision-making competence, defined as tendency to follow normative rational principles in their decision making, is important as it may influence the extent that requirements are met and levels of perceived stress. In addition, perceived stress could be influenced by social orientation and time style; for example, decisions need to comply with given deadlines and the expectations of others. In two studies, with students (n = 118 and professionals (police investigators, n = 90, we examined how the three individual difference features: decision-making competence, social orientation, and time approach relate to perceived stress. Results showed that social orientation and time approach were related to levels of perceived stress, but decision-making competence was not. These results indicate that social orientation and time approach are important to consider in relation to perceived stress, but the role of decision-making competence may be less important for perceived stress. However, the role of decision-making competence for perceived stress needs to be further researched.

Decision-Making Competence, Social Orientation, Time Style, and Perceived Stress.

Science.gov (United States)

Geisler, Martin; Allwood, Carl Martin

2018-01-01

Peoples' decision-making competence, defined as tendency to follow normative rational principles in their decision making, is important as it may influence the extent that requirements are met and levels of perceived stress. In addition, perceived stress could be influenced by social orientation and time style; for example, decisions need to comply with given deadlines and the expectations of others. In two studies, with students ( n = 118) and professionals (police investigators, n = 90), we examined how the three individual difference features: decision-making competence, social orientation, and time approach relate to perceived stress. Results showed that social orientation and time approach were related to levels of perceived stress, but decision-making competence was not. These results indicate that social orientation and time approach are important to consider in relation to perceived stress, but the role of decision-making competence may be less important for perceived stress. However, the role of decision-making competence for perceived stress needs to be further researched.

Decision-Making Competence, Social Orientation, Time Style, and Perceived Stress

Science.gov (United States)

Geisler, Martin; Allwood, Carl Martin

2018-01-01

Peoples’ decision-making competence, defined as tendency to follow normative rational principles in their decision making, is important as it may influence the extent that requirements are met and levels of perceived stress. In addition, perceived stress could be influenced by social orientation and time style; for example, decisions need to comply with given deadlines and the expectations of others. In two studies, with students (n = 118) and professionals (police investigators, n = 90), we examined how the three individual difference features: decision-making competence, social orientation, and time approach relate to perceived stress. Results showed that social orientation and time approach were related to levels of perceived stress, but decision-making competence was not. These results indicate that social orientation and time approach are important to consider in relation to perceived stress, but the role of decision-making competence may be less important for perceived stress. However, the role of decision-making competence for perceived stress needs to be further researched. PMID:29686634

The role of stress in IBS symptom severity

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Sanda Pletikosic

2016-04-01

Full Text Available Irritable bowel syndrome is regarded as a biopsychosocial disorder, the result of a complex combination of predisposing, precipitating and perpetuating factors. Personality traits, affective status and stress are some of the relevant factors contributing to lower quality of life and symptom exacerbation in IBS patients. In order to examine the role of stress in IBS symptom exacerbation, the aims of this study were to explore the relationship of daily stressful events and symptom severity in a prospective manner and to explore the roles of neuroticism, anxiety, depression and stress in the vicious circle of symptom perpetuation. A total of 49 patients with IBS reported their symptom severity and daily stressful events intensity each day for 14 consecutive days. They also completed the Big five personality inventory, the Beck Depression Inventory and the State-trait anxiety inventory. Cross-correlation analyses were performed on the time series data for daily stress and symptom severity for each participant separately. Four different patterns of relationships were found in different subgroups of participants: positive cross-correlations of symptom severity and stress intensity on the same day; higher symptom severity on days following stressful days; lower symptom severity on days following stressful days; and lower stress intensity on days following severe symptoms. Using average scores for daily stress and symptom severity, as well as scores for neuroticism, anxiety and depression, we performed a path analysis to test a model of symptom exacerbation. It showed that, on the group level, average stress intensity predicts average symptom severity. Neuroticism and anxiety were not significant predictors of symptom severity, while depression showed a marginally significant relationship with symptom severity, mediated by stress intensity. In conclusion, depression and daily stress seem to be important contributors to the vicious circle of IBS symptom