Metabolomics Reveals Cryptic Interactive Effects of Species Interactions and Environmental Stress on Nitrogen and Sulfur Metabolism in Seagrass

DEFF Research Database (Denmark)

Hasler-Sheetal, Harald; Castorani, Max C. N.; Glud, Ronnie N.

2016-01-01

Eutrophication of estuaries and coastal seas is accelerating, increasing light stress on subtidal marine plants and changing their interactions with other species. To date, we have limited understanding of how such variations in environmental and biological stress modify the impact of interactions...... among foundational species and eventually affect ecosystem health. Here, we used metabolomics to assess the impact of light reductions on interactions between the seagrass Zostera marina, an important habitat-forming marine plant, and the abundant and commercially important blue mussel Mytilus edulis....... Plant performance varied with light availability but was unaffected by the presence of mussels. Metabolomic analysis, on the other hand, revealed an interaction between light availability and presence of M. edulis on seagrass metabolism. Under high light, mussels stimulated seagrass nitrogen and energy...

Biological Sensitivity to Context: The Interactive Effects of Stress Reactivity and Family Adversity on Socioemotional Behavior and School Readiness

Science.gov (United States)

Obradovic, Jelena; Bush, Nicole R.; Stamperdahl, Juliet; Adler, Nancy E.; Boyce, W. Thomas

2010-01-01

This study examined the direct and interactive effects of stress reactivity and family adversity on socioemotional and cognitive development in three hundred and thirty-eight 5- to 6-year-old children. Neurobiological stress reactivity was measured as respiratory sinus arrhythmia and salivary cortisol responses to social, cognitive, sensory, and…

Interaction between diffusion and chemical stresses

International Nuclear Information System (INIS)

Yang Fuqian

2005-01-01

The present work studies the interaction between chemical stresses and diffusion. A new relation between hydrostatic stress and concentration of solute atoms is established. For a solid free of action of body force, the Laplacian of the hydrostatic stress is proportional to the Laplacian of the concentration of solute atoms, that is, deviation of the hydrostatic stress from its local average is proportional to deviation of the local concentration of solute atoms. A general relationship among surface concentration of solute atoms, normal stress and surface deformation of a solid is then derived, in which the normal stress is dependent on the mean curvature of the undeformed surface and tangential components of the surface displacement. A closed-form solution of the steady state concentration of solute atoms in a thin plate is obtained. It turns out that linear distribution of solute atoms in the plate is non-existent due to the interaction between chemical stresses and diffusion

Interactive effects of dietary restraint and adiposity on stress-induced eating and the food choice of children.

Science.gov (United States)

Roemmich, James N; Lambiase, Maya J; Lobarinas, Christina L; Balantekin, Katherine N

2011-12-01

The Individual Differences Model posits that individual differences in physiological and psychological factors explain eating behaviors in response to stress. The purpose was to determine the effects of individual differences in adiposity, dietary restraint and stress reactivity on children's energy intake and food choices. A total of 40 boys and girls, age 8-12 years, with wide ranges of dietary restraint, adiposity, and stress reactivity were measured for total energy intake and choice of energy dense 'comfort' and lower density 'healthy' foods following reading and speech stressor manipulations. When exploring the interaction of dietary restraint and stress reactivity, lower restraint/lower reactivity and lower restraint/higher reactivity were associated with reductions in energy intake (37-62 kcal) and comfort food (33-89 kcal). Higher restraint/lower reactivity was associated with consuming 86 fewer total kcal and 45 fewer kcal of comfort food. Only higher restraint/higher reactivity predicted increased energy intake (104 kcal) and comfort food (131 kcal). The interaction of dietary restraint and percentage body fat revealed that lower restraint/lower adiposity was associated with consuming 123 fewer kcal after being stressed with the entire reduction due to a decrease in comfort food. Lower restraint/higher adiposity was associated with consuming 116 kcal more after being stressed with 70% (81 kcal) of the increase in the form of comfort foods. Higher restraint/lower adiposity and higher restraint/higher adiposity were associated with smaller changes in total energy intake of 22 kcal and 1 kcal; respectively. Both restraint and adiposity moderated the effect of stress on energy intake and food choice. Children with greater adiposity may be at risk for stress-induced eating to contribute to their obesity. Copyright © 2011 Elsevier Ltd. All rights reserved.

The interaction of chronic restraint stress and voluntary alcohol intake: effects on spatial memory in male rats.

Science.gov (United States)

Gomez, Juan L; Lewis, Michael J; Luine, Victoria N

2012-08-01

Alcohol consumption and exposure to stressful life events activate similar neural pathways and thus result in several comparable physiological and behavioral effects. Alcoholics in treatment claim that life stressors are the leading cause of continued drinking or relapse. However, few studies have investigated the interactive effects of stress and alcohol on cognitive behavior. The effects of restraint stress, alcohol, and stress in combination with alcohol were examined on a spatial memory test, the object placement (OP) task. In addition, intake levels were measured to determine if stress altered general consumption of alcohol. Male Sprague-Dawley rats were assigned to one of four conditions: no alcohol/no stress control (CON), stress alone (STR), alcohol alone (ALC), and STR+alcohol (STR+ALC). Following each restraint stress bout, the STR+ALC and the ALC groups were given access to 8% alcohol for 1h using the two-bottle choice limited access paradigm. As predicted, the STR+ALC group significantly increased alcohol consumption, while the ALC group had consistent drinking over the 10-day treatment. On the OP task, STR and ALC groups performed at chance levels, whereas the CON and STR+ALC groups significantly discriminated between objects in the new and old locations. These data show that stress increases alcohol intake and the intake of alcohol is associated with reduction of the stress-induced impairment of spatial memory. The data have important implications for the development of alcohol abuse and its treatment. Copyright © 2012 Elsevier Inc. All rights reserved.

Ethological Evaluation of the Effects of Social Defeat Stress in Mice: Beyond the Social Interaction Ratio

Science.gov (United States)

Henriques-Alves, Aron M.; Queiroz, Claudio M.

2016-01-01

In rodents, repeated exposure to unavoidable aggression followed by sustained sensory treat can lead to prolonged social aversion. The chronic social defeat stress model explores that phenomenon and it has been used as an animal model for human depression. However, some authors have questioned whether confounding effects may arise as the model also boosts anxiety-related behaviors. Despite its wide acceptance, most studies extract limited information from the behavior of the defeated animal. Often, the normalized occupancy around the social stimulus, the interaction zone, is taken as an index of depression. We hypothesized that this parameter is insufficient to fully characterize the behavioral consequences of this form of stress. Using an ethological approach, we showed that repeated social defeat delayed the expression of social investigation in long (10 min) sessions of social interaction. Also, the incidence of defensive behaviors, including stretched-attend posture and high speed retreats, was significantly higher in defeated mice in comparison to controls. Interestingly, a subpopulation of defeated mice showed recurrent and non-habituating stretched-attend posture and persistent flights during the entire session. Two indexes were created based on defensive behaviors to show that only recurrent flights correlates with sucrose intake. Together, the present study corroborates the idea that this model of social stress can precipitate a myriad of behaviors not readily disentangled. We propose that long sessions (>150 s) and detailed ethological evaluation during social interaction tests are necessary to provide enough information to correctly classify defeated animals in terms of resilience and susceptibility to social defeat stress. PMID:26869895

Ethological Evaluation of the Effects of Social Defeat Stress in Mice: Beyond the Social Interaction Ratio.

Science.gov (United States)

Henriques-Alves, Aron M; Queiroz, Claudio M

2015-01-01

In rodents, repeated exposure to unavoidable aggression followed by sustained sensory treat can lead to prolonged social aversion. The chronic social defeat stress model explores that phenomenon and it has been used as an animal model for human depression. However, some authors have questioned whether confounding effects may arise as the model also boosts anxiety-related behaviors. Despite its wide acceptance, most studies extract limited information from the behavior of the defeated animal. Often, the normalized occupancy around the social stimulus, the interaction zone, is taken as an index of depression. We hypothesized that this parameter is insufficient to fully characterize the behavioral consequences of this form of stress. Using an ethological approach, we showed that repeated social defeat delayed the expression of social investigation in long (10 min) sessions of social interaction. Also, the incidence of defensive behaviors, including stretched-attend posture and high speed retreats, was significantly higher in defeated mice in comparison to controls. Interestingly, a subpopulation of defeated mice showed recurrent and non-habituating stretched-attend posture and persistent flights during the entire session. Two indexes were created based on defensive behaviors to show that only recurrent flights correlates with sucrose intake. Together, the present study corroborates the idea that this model of social stress can precipitate a myriad of behaviors not readily disentangled. We propose that long sessions (>150 s) and detailed ethological evaluation during social interaction tests are necessary to provide enough information to correctly classify defeated animals in terms of resilience and susceptibility to social defeat stress.

Ethological evaluation of the effects of social defeat stress in mice: beyond the social interaction ratio

Directory of Open Access Journals (Sweden)

Aron Miranda Henriques-Alves

2016-02-01

Full Text Available In rodents, repeated exposure to unavoidable aggression followed by sustained sensory treat can lead to prolonged social aversion. The chronic social defeat stress model explores that phenomenon and it has been used as an animal model for human depression. However, some authors have questioned whether confounding effects may arise as the model also boosts anxiety-related behaviors. Despite its wide acceptance, most studies extract limited information from the behavior of the defeated animal. Often, the normalized occupancy around the social stimulus, the interaction zone, is taken as an index of depression. We hypothesized that this parameter is insufficient to fully characterize the behavioral consequences of this form of stress. Using an ethological approach, we showed that repeated social defeat delayed the expression of social investigation in long (10 min sessions of social interaction. Also, the incidence of defensive behaviors, including stretched-attend posture and high speed retreats, was significantly higher in defeated mice in comparison to controls. Interestingly, a subpopulation of defeated mice showed recurrent and non-habituating stretched-attend posture and persistent flights during the entire session. Two indexes were created based on defensive behaviors to show that only recurrent flights correlates with sucrose intake. Together, the present study corroborates the idea that this model of social stress can precipitate a myriad of behaviors not readily disentangled. We propose that long sessions (> 150 s and detailed ethological evaluation during social interaction tests are necessary to provide enough information to correctly classify defeated animals in terms of resilience and susceptibility to social defeat stress.

The effects of heavy metals and their interactions with polycyclic aromatic hydrocarbons on the oxidative stress among coke-oven workers

International Nuclear Information System (INIS)

Wang, Tian; Feng, Wei; Kuang, Dan; Deng, Qifei; Zhang, Wangzhen; Wang, Suhan; He, Meian; Zhang, Xiaomin; Wu, Tangchun; Guo, Huan

2015-01-01

Heavy metals and polycyclic aromatic hydrocarbons (PAHs) are predominate toxic constituents of particulate air pollution that may be related to the increased risk of cardiopulmonary events. We aim to investigate the effects of the toxic heavy metals (arsenic, As; cadmium, Cd; chromium, Cr; nickel, Ni; and lead, Pb), and their interactions with PAHs on oxidative stress among coke-oven workers. A total of 1333 male workers were recruited in this study. We determined their urinary levels of As, Cd, Cr, Ni, Pb, twelve PAH metabolites, 8-hydroxydeoxyguanosine (8-OHdG), and 8-iso-prostaglandin-F2α (8-iso-PGF2α). Multivariate linear regression models were used to analyze the effects of these metals and their interactions with PAHs on 8-OHdG and 8-iso-PGF2α levels. It was found that only urinary As and Ni showed marginal or significant positive linear dose-dependent effects on 8-OHdG in this study population, especially among smokers (β=0.103, P=0.073 and β=0.110, P=0.002, respectively). After stratifying all participants by the quartiles of ΣOH-PAH, all five metals showed linear association with 8-OHdG in the highest quartile subgroup (Q4) of ΣOH-PAHs. However, these five urinary metals showed significantly consistent linear associations with 8-iso-PGF2α in all subjects and each stratum. Urinary ΣOH-PAHs can significant modify the effects of heavy metals on oxidative stress, while co-exposure to both high levels of ΣOH-PAHs and heavy metals render the workers with highest 8-OHdG and 8-iso-PGF2α (all P interaction ≤0.005). This study showed evidence on the interaction effects of heavy metals and PAHs on increasing the oxidative stress, and these results warrant further investigation in more longitudinal studies. - Highlights: • Heavy metals and PAHs are predominate toxic constituents of particulate matters. • Urinary As and Ni showed linear dose-dependent effects on 8-OHdG and 8-iso-PGF2α. • PAHs significant interact with toxic metal in increasing 8-OHd

The effects of heavy metals and their interactions with polycyclic aromatic hydrocarbons on the oxidative stress among coke-oven workers

Energy Technology Data Exchange (ETDEWEB)

Wang, Tian; Feng, Wei; Kuang, Dan; Deng, Qifei [Department of Occupational and Environmental Health, State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China); Zhang, Wangzhen [Institute of Industrial Health, Wuhan Iron & Steel (Group) Corporation, Wuhan 430070, China. (China); Wang, Suhan; He, Meian; Zhang, Xiaomin; Wu, Tangchun [Department of Occupational and Environmental Health, State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China); Guo, Huan, E-mail: ghuan5011@hust.edu.cn [Department of Occupational and Environmental Health, State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China)

2015-07-15

Heavy metals and polycyclic aromatic hydrocarbons (PAHs) are predominate toxic constituents of particulate air pollution that may be related to the increased risk of cardiopulmonary events. We aim to investigate the effects of the toxic heavy metals (arsenic, As; cadmium, Cd; chromium, Cr; nickel, Ni; and lead, Pb), and their interactions with PAHs on oxidative stress among coke-oven workers. A total of 1333 male workers were recruited in this study. We determined their urinary levels of As, Cd, Cr, Ni, Pb, twelve PAH metabolites, 8-hydroxydeoxyguanosine (8-OHdG), and 8-iso-prostaglandin-F2α (8-iso-PGF2α). Multivariate linear regression models were used to analyze the effects of these metals and their interactions with PAHs on 8-OHdG and 8-iso-PGF2α levels. It was found that only urinary As and Ni showed marginal or significant positive linear dose-dependent effects on 8-OHdG in this study population, especially among smokers (β=0.103, P=0.073 and β=0.110, P=0.002, respectively). After stratifying all participants by the quartiles of ΣOH-PAH, all five metals showed linear association with 8-OHdG in the highest quartile subgroup (Q4) of ΣOH-PAHs. However, these five urinary metals showed significantly consistent linear associations with 8-iso-PGF2α in all subjects and each stratum. Urinary ΣOH-PAHs can significant modify the effects of heavy metals on oxidative stress, while co-exposure to both high levels of ΣOH-PAHs and heavy metals render the workers with highest 8-OHdG and 8-iso-PGF2α (all P{sub interaction}≤0.005). This study showed evidence on the interaction effects of heavy metals and PAHs on increasing the oxidative stress, and these results warrant further investigation in more longitudinal studies. - Highlights: • Heavy metals and PAHs are predominate toxic constituents of particulate matters. • Urinary As and Ni showed linear dose-dependent effects on 8-OHdG and 8-iso-PGF2α. • PAHs significant interact with toxic metal in increasing 8

Contributions of Work-Related Stress and Emotional Intelligence to Teacher Engagement: Additive and Interactive Effects.

Science.gov (United States)

Mérida-López, Sergio; Extremera, Natalio; Rey, Lourdes

2017-09-29

This study examined the additive and interactive effects of role stress and emotional intelligence for predicting engagement among 288 teachers. Emotional intelligence and engagement were positively associated. Role ambiguity and role conflict showed negative associations with vigor and dedication scores. The interaction of role ambiguity and emotional intelligence was significant in explaining engagement dimensions. Similar results were found considering overall teacher engagement. Emotional intelligence boosted engagement when the levels of role ambiguity were higher. Our findings suggest the need for future research examining the impact of job hindrances on the links between emotional intelligence and teachers' occupational well-being indicators. Finally, the implications for emotional intelligence training in education are discussed.

Assessing Spurious Interaction Effects in Structural Equation Modeling

Science.gov (United States)

Harring, Jeffrey R.; Weiss, Brandi A.; Li, Ming

2015-01-01

Several studies have stressed the importance of simultaneously estimating interaction and quadratic effects in multiple regression analyses, even if theory only suggests an interaction effect should be present. Specifically, past studies suggested that failing to simultaneously include quadratic effects when testing for interaction effects could…

Species as Stressors: Heterospecific Interactions and the Cellular Stress Response under Global Change.

Science.gov (United States)

Gunderson, Alex R; King, Emily E; Boyer, Kirsten; Tsukimura, Brian; Stillman, Jonathon H

2017-07-01

Anthropogenic global change is predicted to increase the physiological stress of organisms through changes in abiotic conditions such as temperature, pH, and pollution. However, organisms can also experience physiological stress through interactions with other species, especially parasites, predators, and competitors. The stress of species interactions could be an important driver of species' responses to global change as the composition of biological communities change through factors such as distributional and phenological shifts. Interactions between biotic and abiotic stressors could also induce non-linear physiological stress responses under global change. One of the primary means by which organisms deal with physiological stress is through the cellular stress response (CSR), which is broadly the upregulation of a conserved set of genes that facilitate the removal and repair of damaged macromolecules. Here, we present data on behavioral interactions and CSR gene expression for two competing species of intertidal zone porcelain crab (Petrolisthes cinctipes and Petrolisthes manimaculis). We found that P. cinctipes and P. manimaculis engage in more agonistic behaviors when interacting with heterospecifics than conspecifics; however, we found no evidence that heterospecific interactions induced a CSR in these species. In addition to our new data, we review the literature with respect to CSR induction via species interactions, focusing on predator-prey systems and heterospecific competition. We find extensive evidence for predators to induce cellular stress and aspects of the CSR in prey, even in the absence of direct physical contact between species. Effects of heterospecific competition on the CSR have been studied far less, but we do find evidence that agonistic interactions with heterospecifics can induce components of the CSR. Across all published studies, there is clear evidence that species interactions can lead to cellular stress and induction of the CSR

Diffraction stress analysis of thin films; investigating elastic grain interaction

International Nuclear Information System (INIS)

Kumar, A.

2005-12-01

This work is dedicated to the investigation of specimens exhibiting anisotropic microstructures (and thus macroscopic elastic anisotropy) and/or inhomogeneous microstructures, as met near surfaces and in textured materials. The following aspects are covered: (i) Analysis of specimens with direction-dependent (anisotropic) elastic grain-interaction. Elastic grain-interaction determines the distribution of stresses and strains over the (crystallographically) differently oriented grains of a mechanically stressed polycrystal and the mechanical and diffraction (X-ray) elastic constants (relating (diffraction) lattice strains to mechanical stresses). Grain interaction models that allow for anisotropic, direction-dependent grain interaction have been developed very recently. The notion 'direction-dependent' grain-interaction signifies that different grain-interaction constraints prevail along different directions in a specimen. Practical examples of direction-dependent grain interaction are the occurrence of surface anisotropy in thin films and the surface regions of bulk polycrystals and the occurrence of grain-shape (morphological) texture. In this work, for the first time, stress analyses of thin films have been performed on the basis of these newly developed grain-interaction models. It has also been demonstrated that the identification of the (dominant) source of direction-dependent grain interaction is possible. The results for the grain interaction have been discussed in the light of microstructural investigations of the specimens by microscopic techniques. (ii) Analysis of specimens with depth gradients: Diffraction stress analysis can be hindered if gradients of the stress state, the composition or the microstructure occur in the specimen under investigation, as the so-called information depth varies in the course of a traditional stress measurement: Ambiguous results are thus generally obtained. In this work, a strategy for stress measurements at fixed

Interactive effect of biochar and plant growth-promoting bacterial endophytes on ameliorating salinity stress in maize

DEFF Research Database (Denmark)

Saleem Akhtar, Saqib; Andersen, Mathias Neumann; Naveed, Muhammad

2015-01-01

The objective of this work was to study the interactive effect of biochar and plant growth-promoting endophytic bacteria containing 1-aminocyclopropane-1-carboxylate deaminase and exopolysaccharide activity on mitigating salinity stress in maize (Zea mays L.). The plants were grown in a greenhouse...... under controlled conditions, and were subjected to separate or combined treatments of biochar (0% and 5%, w/w) and two endophytic bacterial strains (Burkholderia phytofirmans (PsJN) and Enterobacter sp. (FD17)) and salinity stress. The results indicated that salinity significantly decreased the growth...... of maize, whereas both biochar and inoculation mitigated the negative effects of salinity on maize performance either by decreasing the xylem Na+ concentration ([Na+]xylem) uptake or by maintaining nutrient balance within the plant, especially when the two treatments were applied in combination. Moreover...

Animal models of social stress: the dark side of social interactions.

Science.gov (United States)

Masis-Calvo, Marianela; Schmidtner, Anna K; de Moura Oliveira, Vinícius E; Grossmann, Cindy P; de Jong, Trynke R; Neumann, Inga D

2018-05-10

Social stress occurs in all social species, including humans, and shape both mental health and future interactions with conspecifics. Animal models of social stress are used to unravel the precise role of the main stress system - the HPA axis - on the one hand, and the social behavior network on the other, as these are intricately interwoven. The present review aims to summarize the insights gained from three highly useful and clinically relevant animal models of psychosocial stress: the resident-intruder (RI) test, the chronic subordinate colony housing (CSC), and the social fear conditioning (SFC). Each model brings its own focus: the role of the HPA axis in shaping acute social confrontations (RI test), the physiological and behavioral impairments resulting from chronic exposure to negative social experiences (CSC), and the neurobiology underlying social fear and its effects on future social interactions (SFC). Moreover, these models are discussed with special attention to the HPA axis and the neuropeptides vasopressin and oxytocin, which are important messengers in the stress system, in emotion regulation, as well as in the social behavior network. It appears that both nonapeptides balance the relative strength of the stress response, and simultaneously predispose the animal to positive or negative social interactions.

Predicting behavior during interracial interactions: a stress and coping approach.

Science.gov (United States)

Trawalter, Sophie; Richeson, Jennifer A; Shelton, J Nicole

2009-11-01

The social psychological literature maintains unequivocally that interracial contact is stressful. Yet research and theory have rarely considered how stress may shape behavior during interracial interactions. To address this empirical and theoretical gap, the authors propose a framework for understanding and predicting behavior during interracial interactions rooted in the stress and coping literature. Specifically, they propose that individuals often appraise interracial interactions as a threat, experience stress, and therefore cope-they antagonize, avoid, freeze, or engage. In other words, the behavioral dynamics of interracial interactions can be understood as initial stress reactions and subsequent coping responses. After articulating the framework and its predictions for behavior during interracial interactions, the authors examine its ability to organize the extant literature on behavioral dynamics during interracial compared with same-race contact. They conclude with a discussion of the implications of the stress and coping framework for improving research and fostering more positive interracial contact.

Contributions of Work-Related Stress and Emotional Intelligence to Teacher Engagement: Additive and Interactive Effects

Directory of Open Access Journals (Sweden)

Sergio Mérida-López

2017-09-01

Full Text Available This study examined the additive and interactive effects of role stress and emotional intelligence for predicting engagement among 288 teachers. Emotional intelligence and engagement were positively associated. Role ambiguity and role conflict showed negative associations with vigor and dedication scores. The interaction of role ambiguity and emotional intelligence was significant in explaining engagement dimensions. Similar results were found considering overall teacher engagement. Emotional intelligence boosted engagement when the levels of role ambiguity were higher. Our findings suggest the need for future research examining the impact of job hindrances on the links between emotional intelligence and teachers’ occupational well-being indicators. Finally, the implications for emotional intelligence training in education are discussed.

Contributions of Work-Related Stress and Emotional Intelligence to Teacher Engagement: Additive and Interactive Effects

Science.gov (United States)

2017-01-01

This study examined the additive and interactive effects of role stress and emotional intelligence for predicting engagement among 288 teachers. Emotional intelligence and engagement were positively associated. Role ambiguity and role conflict showed negative associations with vigor and dedication scores. The interaction of role ambiguity and emotional intelligence was significant in explaining engagement dimensions. Similar results were found considering overall teacher engagement. Emotional intelligence boosted engagement when the levels of role ambiguity were higher. Our findings suggest the need for future research examining the impact of job hindrances on the links between emotional intelligence and teachers’ occupational well-being indicators. Finally, the implications for emotional intelligence training in education are discussed. PMID:28961218

Gene by cognition interaction on stress-induced attention bias for food: Effects of 5-HTTLPR and ruminative thinking.

Science.gov (United States)

Schepers, Robbie; Markus, C Rob

2017-09-01

Stress is often found to increase the preference and intake of high caloric foods. This effect is known as emotional eating and is influenced by cognitive as well as biological stress vulnerabilities. An S-allele of the 5-HTTLPR gene has been linked to decreased (brain) serotonin efficiency, leading to decreased stress resilience and increased risks for negative affect and eating related disturbances. Recently it has been proposed that a cognitive ruminative thinking style can further exacerbate the effect of this gene by prolonging the already increased stress response, thereby potentially increasing the risk of compensating by overeating high palatable foods. This study was aimed at investigating whether there is an increased risk for emotional eating in high ruminative S/S-allele carriers reflected by an increased attention bias for high caloric foods during stress. From a large (N=827) DNA database, participants (N=100) were selected based on genotype (S/S or L/L) and ruminative thinking style and performed an eye-tracking visual food-picture probe task before and after acute stress exposure. A significant Genotype x Rumination x Stress-interaction was found on attention bias for savory food; indicating that a stress-induced attention bias for specifically high-caloric foods is moderated by a gene x cognitive risk factor. Both a genetic (5-HTTLPR) and cognitive (ruminative thinking) stress vulnerability may mutually increase the risk for stress-related abnormal eating patterns. Copyright © 2017 Elsevier B.V. All rights reserved.

Interaction of stress with the martensitic phase transition in A15 compounds

International Nuclear Information System (INIS)

Welch, D.O.

1981-01-01

Recently there has been a resurgence of interest in the effect of the martensitic phase transition which occurs in many A15 compounds on superconductivity and on elastic and anelastic behavior. Since in many practical applications, A15 compounds are subject to considerable stress and strain, it is of interest to examine the interaction of stress with the martensitic transition; this paper is an examination of the effects of stress predicted by a simple Landau model which successfully describes many features of the transition and the related temperature dependence of the elastic modulus (c 11 -c 12 )/2. The effect of stress on the temperature ranges of stability and metastability of various types of martensitic domain is discussed. The non-linearity of the stress-strain relation in a polycrystalline A15 is studied

Sex-specific effects of early life stress on social interaction and prefrontal cortex dendritic morphology in young rats.

Science.gov (United States)

Farrell, M R; Holland, F H; Shansky, R M; Brenhouse, H C

2016-09-01

Early life stress has been linked to depression, anxiety, and behavior disorders in adolescence and adulthood. The medial prefrontal cortex (mPFC) is implicated in stress-related psychopathology, is a target for stress hormones, and mediates social behavior. The present study investigated sex differences in early-life stress effects on juvenile social interaction and adolescent mPFC dendritic morphology in rats using a maternal separation (MS) paradigm. Half of the rat pups of each sex were separated from their mother for 4h a day between postnatal days 2 and 21, while the other half remained with their mother in the animal facilities and were exposed to minimal handling. At postnatal day 25 (P25; juvenility), rats underwent a social interaction test with an age and sex matched conspecific. Distance from conspecific, approach and avoidance behaviors, nose-to-nose contacts, and general locomotion were measured. Rats were euthanized at postnatal day 40 (P40; adolescence), and randomly selected infralimbic pyramidal neurons were filled with Lucifer yellow using iontophoretic microinjections, imaged in 3D, and then analyzed for dendritic arborization, spine density, and spine morphology. Early-life stress increased the latency to make nose-to-nose contact at P25 in females but not males. At P40, early-life stress increased infralimbic apical dendritic branch number and length and decreased thin spine density in stressed female rats. These results indicate that MS during the postnatal period influenced juvenile social behavior and mPFC dendritic arborization in a sex-specific manner. Copyright © 2016 Elsevier B.V. All rights reserved.

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.

Stressful Social Interactions Experienced by Adults with Mild Intellectual Disability

Science.gov (United States)

Hartley, Sigan L.; MacLean, William E., Jr.

2009-01-01

Adults with intellectual disability are vulnerable to stressful social interactions. We determined frequency and severity of various stressful social interactions, identified the social partners in these interactions, and examined the specific interpersonal skill difficulties of 114 adults with mild intellectual disability. Participants'…

Main and interactive effects of shiftwork, age and work stress on health in an Italian sample of healthcare workers

DEFF Research Database (Denmark)

Conway, Paul Maurice; Campanini, P; Sartori, S

2008-01-01

Among healthcare workers, shiftwork (mostly if nightwork is also included), ageing and work-related stress may be factors leading to impaired health. Such risk factors may also operate in interaction, resulting in an even increased harm for health. The present study aims at evaluating...... gastrointestinal disorders, poor work ability and job dissatisfaction. Work stress was the risk factor with the highest relevance for poor health. Ageing was associated with lower physical health. Few significant interactions were observed. Shiftwork with nights and high work stress significantly interacted...

Interaction between the RGS6 gene and psychosocial stress on obesity-related traits.

Science.gov (United States)

Kim, Hyun-Jin; Min, Jin-Young; Min, Kyoung-Bok

2017-03-31

Obesity is a major risk factor for chronic diseases and arises from the interactions between environmental factors and multiple genes. Psychosocial stress may affect the risk for obesity, modifying food intake and choice. A recent study suggested regulator of G-protein signaling 6 (RGS6) as a novel candidate gene for obesity in terms of reward-related feeding under stress. In this study, we tried to verify the unidentified connection between RGS6 and human obesity with psychosocial stress in a Korean population. A total of 1,462 adult subjects, who participated in the Korean Association Resource cohort project, were included for this analysis. Obesity-related traits including waist circumference, body mass index, and visceral adipose tissue were recorded. A total of 4 intronic SNPs for the RGS6 gene were used for this study. We found that interactions between SNP rs2239219 and psychosocial stress are significantly associated with abdominal obesity (p = 0.007). As risk allele of this SNP increased, prevalence of abdominal obesity under high-stress conditions gradually increased (p = 0.013). However, we found no SNPs-by-stress interaction effect on other adiposity phenotypes. This study suggests that RGS6 is closely linked to stress-induced abdominal obesity in Korean adults.

Interactive Contributions of Cumulative Peer Stress and Executive Function Deficits to Depression in Early Adolescence

Science.gov (United States)

Agoston, Anna M.; Rudolph, Karen D.

2016-01-01

Exposure to peer stress contributes to adolescent depression, yet not all youth experience these effects. Thus, it is important to identify individual differences that shape the consequences of peer stress. This research investigated the interactive contribution of cumulative peer stress during childhood (second-fifth grades) and executive…

The stressed eyewitness: The interaction of thematic arousal and post-event stress in memory for central and peripheral event information

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Gerald eEchterhoff

2012-08-01

Full Text Available Both arousal during the encoding of stimuli and subsequent stress can affect memory, often by increasing memory for important or central information. We explored whether event-based (thematic arousal and post-event stress interact to selectively enhance eyewitnesses’ memory for the central aspects of an observed incident. Specifically, we argue that memory for stimuli should be enhanced when (a the stimuli are encoded under arousal (vs. non-arousal, and (b stress is experienced soon after the encoding episode.We designed an experiment that extended previous research by manipulating arousal without changing the stimulus material, distinguishing between central and peripheral event information, and using a dynamic, life-like event instead of static pictures. After watching a video depicting a burglary under high or low thematic arousal, psychosocial stress was induced or not induced by the Trier Social Stress Test. Salivary cortisol was measured at standard intervals. Consistent with our prediction, we found a significant thematic arousal x post-event stress x centrality interaction, indicating that the recognition advantage for central event items over peripheral event items was most pronounced under both high thematic arousal and post-event stress. Because stress was induced after encoding this interaction cannot be explained by possible differences at encoding, such as narrowed attention. The centrality effect of post-event stress under high thematic arousal was statistically mediated by the cortisol increase, which suggests a key role of the stress hormone. We discuss implications of our findings for psychological and neuroscientific theories of emotional memory formation.

Gene-Environment Interaction Effects of Peer Deviance, Parental Knowledge and Stressful Life Events on Adolescent Alcohol Use.

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Cooke, Megan E; Meyers, Jacquelyn L; Latvala, Antti; Korhonen, Tellervo; Rose, Richard J; Kaprio, Jaakko; Salvatore, Jessica E; Dick, Danielle M

2015-10-01

The purpose of this study was to address two methodological issues that have called into question whether previously reported gene-environment interaction (GxE) effects for adolescent alcohol use are 'real'. These issues are (1) the potential correlation between the environmental moderator and the outcome across twins and (2) non-linear transformations of the behavioral outcome. Three environments that have been previously studied (peer deviance, parental knowledge, and potentially stressful life events) were examined here. For each moderator (peer deviance, parental knowledge, and potentially stressful life events), a series of models was fit to both a raw and transformed measure of monthly adolescent alcohol use in a sample that included 825 dizygotic (DZ) and 803 monozygotic (MZ) twin pairs. The results showed that the moderating effect of peer deviance was robust to transformation, and that although the significance of moderating effects of parental knowledge and potentially stressful life events were dependent on the scale of the adolescent alcohol use outcome, the overall results were consistent across transformation. In addition, the findings did not vary across statistical models. The consistency of the peer deviance results and the shift of the parental knowledge and potentially stressful life events results between trending and significant, shed some light on why previous findings for certain moderators have been inconsistent and emphasize the importance of considering both methodological issues and previous findings when conducting and interpreting GxE analyses.

Effects of lifetime stress exposure on mental and physical health in young adulthood: How stress degrades and forgiveness protects health.

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Toussaint, Loren; Shields, Grant S; Dorn, Gabriel; Slavich, George M

2016-06-01

To examine risk and resilience factors that affect health, lifetime stress exposure histories, dispositional forgiveness levels, and mental and physical health were assessed in 148 young adults. Greater lifetime stress severity and lower levels of forgiveness each uniquely predicted worse mental and physical health. Analyses also revealed a graded Stress × Forgiveness interaction effect, wherein associations between stress and mental health were weaker for persons exhibiting more forgiveness. These data are the first to elucidate the interactive effects of cumulative stress severity and forgiveness on health, and suggest that developing a more forgiving coping style may help minimize stress-related disorders. © The Author(s) 2014.

Expectancy of Stress-Reducing Aromatherapy Effect and Performance on a Stress-Sensitive Cognitive Task

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Chamine, Irina; Oken, Barry S.

2015-01-01

Objective. Stress-reducing therapies help maintain cognitive performance during stress. Aromatherapy is popular for stress reduction, but its effectiveness and mechanism are unclear. This study examined stress-reducing effects of aromatherapy on cognitive function using the go/no-go (GNG) task performance and event related potentials (ERP) components sensitive to stress. The study also assessed the importance of expectancy in aromatherapy actions. Methods. 81 adults were randomized to 3 aroma groups (active experimental, detectable, and undetectable placebo) and 2 prime subgroups (prime suggesting stress-reducing aroma effects or no-prime). GNG performance, ERPs, subjective expected aroma effects, and stress ratings were assessed at baseline and poststress. Results. No specific aroma effects on stress or cognition were observed. However, regardless of experienced aroma, people receiving a prime displayed faster poststress median reaction times than those receiving no prime. A significant interaction for N200 amplitude indicated divergent ERP patterns between baseline and poststress for go and no-go stimuli depending on the prime subgroup. Furthermore, trends for beneficial prime effects were shown on poststress no-go N200/P300 latencies and N200 amplitude. Conclusion. While there were no aroma-specific effects on stress or cognition, these results highlight the role of expectancy for poststress response inhibition and attention. PMID:25802539

Expectancy of Stress-Reducing Aromatherapy Effect and Performance on a Stress-Sensitive Cognitive Task

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Irina Chamine

2015-01-01

Full Text Available Objective. Stress-reducing therapies help maintain cognitive performance during stress. Aromatherapy is popular for stress reduction, but its effectiveness and mechanism are unclear. This study examined stress-reducing effects of aromatherapy on cognitive function using the go/no-go (GNG task performance and event related potentials (ERP components sensitive to stress. The study also assessed the importance of expectancy in aromatherapy actions. Methods. 81 adults were randomized to 3 aroma groups (active experimental, detectable, and undetectable placebo and 2 prime subgroups (prime suggesting stress-reducing aroma effects or no-prime. GNG performance, ERPs, subjective expected aroma effects, and stress ratings were assessed at baseline and poststress. Results. No specific aroma effects on stress or cognition were observed. However, regardless of experienced aroma, people receiving a prime displayed faster poststress median reaction times than those receiving no prime. A significant interaction for N200 amplitude indicated divergent ERP patterns between baseline and poststress for go and no-go stimuli depending on the prime subgroup. Furthermore, trends for beneficial prime effects were shown on poststress no-go N200/P300 latencies and N200 amplitude. Conclusion. While there were no aroma-specific effects on stress or cognition, these results highlight the role of expectancy for poststress response inhibition and attention.

Contact interactions, stress and material symmetry

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Podio-Guidugli P.

2002-01-01

Full Text Available An argument is given intimating that, for nonsimple materials, the concepts of contact interaction and material symmetry, as well as the bridging concept of stress, should be carefully revised and generalized. .

Interaction of prechilling, temperature, osmotic stress, and light in Picea abies seed germination

International Nuclear Information System (INIS)

Leinonen, K.; Rita, H.

1995-01-01

A multi-factor experimental approach and proportional odds model was used to study interactions between five environmental factors significant to Norway spruce seed germination: prechilling (at +4.5 °C), suboptimal temperatures (+12 and +16 °C), osmotically induced water stress (–0.3 Mpa and 0 Mpa), prolonged white light, and short-period far-red light. Temperature and osmotic stress interacted with one another in the germination of seeds: the effect of osmotic stress being stronger at +16 °C than at +12 °C. In natural conditions, this interaction may prevent germination early in the summer when soil dries and temperature increases. Prolonged white light prevented germination at low temperature and low osmotic potential. Inhibitory effect was less at higher temperatures and higher osmotic potential, as well as after prechilling. Short-period far-red light did not prevent germination of unchilled seeds in darkness. Prechilling tended to make seeds sensitive to short pulses of far-red light, an effect which depended on temperature: at +12 °C the effect on germination was promotive, but at +16 °C, inhibitory and partly reversible by white light. It seems that Norway spruce seeds may have adapted to germinate in canopy shade light rich in far-red. The seeds may also have evolved mechanisms to inhibit germination in prolonged light

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.

Laplace-SGBEM analysis of the dynamic stress intensity factors and the dynamic T-stress for the interaction between a crack and auxetic inclusions

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Kwon, Kibum

A dynamic analysis of the interaction between a crack and an auxetic (negative Poisson ratio)/non-auxetic inclusion is presented. The two most important fracture parameters, namely the stress intensity factors and the T-stress are analyzed by using the symmetric Galerkin boundary element method in the Laplace domain for three different models of crack-inclusion interaction. To investigate the effects of auxetic inclusions on the fracture behavior of composites reinforced by this new type of material, comparisons of the dynamic stress intensity factors and the dynamic T-stress are made between the use of auxetic inclusions as opposed to the use of traditional inclusions. Furthermore, the technique presented in this research can be employed to analyze for the interaction between a crack and a cluster of auxetic/non-auxetic inclusions. Results from the latter models can be employed in crack growth analysis in auxetic-fiber-reinforced composites.

Daily stress interacts with trait dissociation to predict sleep-related experiences in young adults.

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Soffer-Dudek, Nirit; Shahar, Golan

2011-08-01

Building on the previously documented effects of stress and dissociation on sleep and dreaming, we examined their interactive role in general sleep-related experiences (GSEs; e.g., nightmares, falling dreams, hypnagogic hallucinations; see Watson, 2001). Stress, sleep quality, and GSEs were assessed daily for 14 days among young adults. Baseline assessment included life stress, sleep quality, psychopathology, dissociation, and related dimensions. Multilevel analyses indicated that daily stress brings about GSEs among highly dissociative young adults. Additionally, baseline trait dissociation predicted within-subject elevation in GSEs when daily stress was high. Flawed sleep-wake transitions, previously linked to dissociation and sleep-related experiences, might account for this effect. © 2011 American Psychological Association

Timing of favorable conditions, competition and fertility interact to govern recruitment of invasive Chinese tallow tree in stressful environments.

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Christopher A Gabler

Full Text Available The rate of new exotic recruitment following removal of adult invaders (reinvasion pressure influences restoration outcomes and costs but is highly variable and poorly understood. We hypothesize that broad variation in average reinvasion pressure of Triadica sebifera (Chinese tallow tree, a major invader arises from differences among habitats in spatiotemporal availability of realized recruitment windows. These windows are periods of variable duration long enough to permit establishment given local environmental conditions. We tested this hypothesis via a greenhouse mesocosm experiment that quantified how the duration of favorable moisture conditions prior to flood or drought stress (window duration, competition and nutrient availability influenced Triadica success in high stress environments. Window duration influenced pre-stress seedling abundance and size, growth during stress and final abundance; it interacted with other factors to affect final biomass and germination during stress. Stress type and competition impacted final size and biomass, plus germination, mortality and changes in size during stress. Final abundance also depended on competition and the interaction of window duration, stress type and competition. Fertilization interacted with competition and stress to influence biomass and changes in height, respectively, but did not affect Triadica abundance. Overall, longer window durations promoted Triadica establishment, competition and drought (relative to flood suppressed establishment, and fertilization had weak effects. Interactions among factors frequently produced different effects in specific contexts. Results support our 'outgrow the stress' hypothesis and show that temporal availability of abiotic windows and factors that influence growth rates govern Triadica recruitment in stressful environments. These findings suggest that native seed addition can effectively suppress superior competitors in stressful environments. We also

Psychostimulants and forced swim stress interaction: how activation of the hypothalamic-pituitary-adrenal axis and stress-induced hyperglycemia are affected.

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Gagliano, Humberto; Ortega-Sanchez, Juan Antonio; Nadal, Roser; Armario, Antonio

2017-10-01

We recently reported that simultaneous exposure to amphetamine and various stressors resulted in reduced hypothalamic-pituitary-adrenal (HPA) and glycemic responses to the stressors. Since this is a new and relevant phenomenon, we wanted to further explore this interaction. This study aims (i) to characterize the effect of various doses of amphetamine on the physiological response to a predominantly emotional stressor (forced swim) when the drug was given immediately before stress; (ii) to study if an interaction appears when the drug was given 30 min or 7 days before swim; and (iii) to know whether cocaine causes similar effects when given just before stress. Adult male rats were used and plasma levels of ACTH, corticosterone, and glucose were the outcomes. Amphetamine caused a dose-dependent activation of the HPA axis, but all doses reduced HPA and glycemic responses to swim when given just before the stressor. Importantly, during the post-swim period, the stressor potently inhibited the ACTH response to amphetamine, demonstrating mutual inhibition between the two stimuli. The highest dose of amphetamine also reduced the response to swim when given 30 min before stress, whereas it caused HPA sensitization when given 7 days before. Cocaine also reduced stress-induced HPA activation when given just before swim. The present results demonstrate a negative synergy between psychostimulants (amphetamine and cocaine) and stress regarding HPA and glucose responses when rats were exposed simultaneously to both stimuli. The inhibitory effect of amphetamine is also observed when given shortly before stress, but not some days before.

Stress and Cognitive Load in Multimodal Conversational Interactions

NARCIS (Netherlands)

Niculescu, A.I.; Cao, Y.; Nijholt, Antinus; Stephanides, C.

2009-01-01

The quality assessment of multimodal conversational interactions is determined by many influence parameters. Stress and cognitive load are two of them. In order to assess the impact of stress and cognitive load on the perceived conversational quality it is essential to control their levels during

Numerical analysis of interacting cracks in biaxial stress field

International Nuclear Information System (INIS)

Kovac, M.; Cizelj, L.

1999-01-01

The stress corrosion cracks as seen for example in PWR steam generator tubing made of Inconel 600 usually produce highly irregular kinked and branched crack patterns. Crack initialization and propagation depends on stress state underlying the crack pattern. Numerical analysis (such as finite element method) of interacting kinked and branched cracks can provide accurate solutions. This paper discusses the use of general-purpose finite element code ABAQUS for evaluating stress fields at crack tips of interacting complex cracks. The results obtained showed reasonable agreement with the reference solutions and confirmed use of finite elements in such class of problems.(author)

Tensile stress dependence of the magnetostatic interaction between Fe-rich wires

International Nuclear Information System (INIS)

Gawronski, P.; Zhukov, A.; Blanco, J.M.; Gonzalez, J.; KuIakowski, K.

2005-01-01

We study the influence of the applied tensile stress on the magnetostatic interaction between two amorphous Fe-rich wires. The hysteresis loop is measured for: (i) conventional wires produced by in-rotation-water method, with diameter of 125μm (ii) cold-drawn wires with diameter of 50μm. The stress dependence of the interaction field is evaluated from the shape of the hysteresis loops, which show characteristic two-step behaviour. These steps mark the values of the switching field of the wires. For the conventional wires the tensile stress dependence of the interaction field can be explained as a result of the tensile stress dependence of the magnetization. For the cold-drawn wires, the interaction field shows a maximum with the applied stress. This behaviour is interpreted as a consequence of a local variation of the domain structure at the wire ends. It modifies the stray field, and-as a consequence-the switching field of the neighbouring wire

Stress in Marital Interaction and Change in Depression: A Longitudinal Analysis.

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Schafer, Robert B.; Wickrama, K. A. S.; Keith, Pat M.

1998-01-01

A model of the effects of two types of stress in everyday marital interaction on change in depressive symptoms is investigated. Mediating variables are unfavorable reflected appraisals, low competency, self-efficacy, and self-esteem. Participants (N=98 couples) were interviewed twice. The data supported the model. (Author/EMK)

Work-Based Social Interactions, Perceived Stress, and Workload Incongruence as Antecedents of Athletic Trainer Burnout.

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DeFreese, J D; Mihalik, Jason P

2016-01-01

Burnout is an important psychological health concern for working professionals. Understanding how psychological stress and markers of workload contribute to athletic trainers' (ATs') perceptions of burnout is highly valuable. Both positive (social support) and negative social interactions should be considered when examining relationships among markers of ATs' health and wellbeing. To examine the potential effects of social interactions on the relationships between (1) burnout and perceived stress and (2) burnout and workload incongruence in ATs. Cross-sectional study. Participating ATs completed a computer-based survey during the fall sports season. Responding participants were ATs randomly sampled from the National Athletic Trainers' Association membership (N = 154; men = 78, women = 76; age = 36.8 ± 9.5 years). Participants completed self-report assessments (Perceived Stress Scale, Social Support Questionnaire, Positive and Negative Social Exchanges, Maslach Burnout Inventory-Human Services Survey) via a secure e-mail link. Workload incongruence was calculated by subtracting anticipated work hours from actual current work hours (6.0 ± 9.6 hours). We used hierarchical multiple regression analyses to examine hypothesized relationships among study variables. Social interactions did not affect the relationships between burnout and perceived stress or workload incongruence at the global or dimensional level. However, perceived stress (β = .47, P stress perceptions and social support drive the dimensional AT burnout experience, whereas workload incongruence (emotional exhaustion) and negative social interactions (depersonalization) were linked to specific burnout dimensions. Social interactions and markers of stress and workload should be considered when seeking to understand ATs' experiences with burnout and to design workplace interventions.

The interactive effects of multiple stressors on physiological stress responses and club cell investment in fathead minnows

International Nuclear Information System (INIS)

Manek, Aditya K.; Ferrari, Maud C.O.; Niyogi, Som; Chivers, Douglas P.

2014-01-01

Anthropogenic activities have dramatically increased over the past decades, with the consequence that many organisms are simultaneously exposed to multiple stressors. Understanding how organisms respond to these stressors is a key focus for scientists from many disciplines. Here we investigated the interactive effects of two stressors, UV radiation (UVR) and cadmium (Cd) exposure on a common freshwater fish, fathead minnow (Pimephales promelas). UVR is known to influence the density of epidermal club cells (ECCs), which are not only a key component of the innate immune system of fishes, but are also the source of chemical alarm cues that serve to warn other fishes of nearby predators. In contrast, Cd impairs the physiological stress response and ability of fish to respond to alarm cues. We used an integrative approach to examine physiological stress response as well as investment in ECCs. Fish exposed to UVR had higher levels of cortisol than non-exposed controls, but Cd reduced cortisol levels substantially for fish exposed to UVR. Fish exposed to UVR, either in the presence or absence of Cd, showed consistent decreases in ECC investment compared to non-exposed controls. Despite differences in ECC number, there was no difference in the potency of alarm cues prepared from the skin of UVR and Cd exposed or non-exposed fish indicating that UVR and Cd exposure combined may have little influence on chemically-mediated predator–prey interactions. - Highlights: • UV radiation caused a physiological stress response (cortisol release) in fish. • Cd reduced cortisol levels substantially for fish exposed to UV. • Fish exposed to UV, with or without Cd, showed decreases in club cell investment. • There was no difference in alarm cues potency from UV and Cd exposed fish. • Our work highlights the difficulty of untangling effects of multiple stressors

The interactive effects of multiple stressors on physiological stress responses and club cell investment in fathead minnows

Energy Technology Data Exchange (ETDEWEB)

Manek, Aditya K., E-mail: aditya.manek@usask.ca [Department of Biology, University of Saskatchewan, Saskatoon, S7N 5E2 SK (Canada); Ferrari, Maud C.O. [Department of Biomedical Sciences, WCVM, University of Saskatchewan, Saskatoon, SK S7N 5B4 (Canada); Niyogi, Som; Chivers, Douglas P. [Department of Biology, University of Saskatchewan, Saskatoon, S7N 5E2 SK (Canada)

2014-04-01

Anthropogenic activities have dramatically increased over the past decades, with the consequence that many organisms are simultaneously exposed to multiple stressors. Understanding how organisms respond to these stressors is a key focus for scientists from many disciplines. Here we investigated the interactive effects of two stressors, UV radiation (UVR) and cadmium (Cd) exposure on a common freshwater fish, fathead minnow (Pimephales promelas). UVR is known to influence the density of epidermal club cells (ECCs), which are not only a key component of the innate immune system of fishes, but are also the source of chemical alarm cues that serve to warn other fishes of nearby predators. In contrast, Cd impairs the physiological stress response and ability of fish to respond to alarm cues. We used an integrative approach to examine physiological stress response as well as investment in ECCs. Fish exposed to UVR had higher levels of cortisol than non-exposed controls, but Cd reduced cortisol levels substantially for fish exposed to UVR. Fish exposed to UVR, either in the presence or absence of Cd, showed consistent decreases in ECC investment compared to non-exposed controls. Despite differences in ECC number, there was no difference in the potency of alarm cues prepared from the skin of UVR and Cd exposed or non-exposed fish indicating that UVR and Cd exposure combined may have little influence on chemically-mediated predator–prey interactions. - Highlights: • UV radiation caused a physiological stress response (cortisol release) in fish. • Cd reduced cortisol levels substantially for fish exposed to UV. • Fish exposed to UV, with or without Cd, showed decreases in club cell investment. • There was no difference in alarm cues potency from UV and Cd exposed fish. • Our work highlights the difficulty of untangling effects of multiple stressors.

Ultraviolet-B and water stress effects on growth, gas exchange and oxidative stress in sunflower plants.

Science.gov (United States)

Cechin, Inês; Corniani, Natália; de Fátima Fumis, Terezinha; Cataneo, Ana Catarina

2008-07-01

The effects and interaction of drought and UV-B radiation were studied in sunflower plants (Helianthus annuus L. var. Catissol-01), growing in a greenhouse under natural photoperiod conditions. The plants received approximately 1.7 W m(-2) (controls) or 8.6 W m(-2) (+UV-B) of UV-B radiation for 7 h per day. The UV-B and water stress treatments started 18 days after sowing. After a period of 12 days of stress, half of the water-stressed plants (including both UV-B irradiated or non-irradiated) were rehydrated. Both drought and UV-B radiation treatments resulted in lower shoot dry matter per plant, but there was no significant interaction between the two treatments. Water stress and UV-B radiation reduced photosynthesis, stomatal conductance and transpiration. However, the amplitude of the effects of both stressors was dependent on the interactions. This resulted in alleviation of the negative effect of drought on photosynthesis and transpiration by UV-B radiation as the water stress intensified. Intercelluar CO(2) concentration was initially reduced in all treatments compared to control plants but it increased with time. Photosynthetic pigments were not affected by UV-B radiation. Water stress reduced photosynthetic pigments only under high UV-B radiation. The decrease was more accentuated for chlorophyll a than for chlorophyll b. As a measure for the maximum efficiency of photosystem II in darkness F (v)/F (m) was used, which was not affected by drought stress but initially reduced by UV-B radiation. Independent of water supply, UV-B radiation increased the activity of pirogalol peroxidase and did not increase the level of malondialdehyde. On the other hand, water stress did not alter the activity of pirogalol peroxidase and caused membrane damage as assessed by lipid peroxidation. The application of UV-B radiation together with drought seemed to have a protective effect by lowering the intensity of lipid peroxidation caused by water stress. The content of proline

Interaction between 5-HTTLPR genotype and cognitive stress vulnerability on sleep quality: effects of sub-chronic tryptophan administration.

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van Dalfsen, Jens H; Markus, C Rob

2015-02-02

Abundant evidence suggests that allelic variation in the serotonin transporter-linked polymorphic region (5-HTTLPR) influences susceptibility to stress and its affective consequences due to brain serotonergic vulnerability. Based on recent assumptions, the present study examined whether the 5-HTTLPR genotype may also interact with a vulnerability to chronic stress experience (conceptualized by trait neuroticism) in order to influence sleep quality and, additionally, whether this is influenced by brain serotonergic manipulations. In a well-balanced experimental design, homozygous S-allele (n = 57) and L-allele (n = 54) genotypes with high and low chronic stress vulnerability (neuroticism) were first assessed for general past sleep quality during a month before onset of the experiment. Then subjects were assessed for sleep quality following 7 days of tryptophan (3.0g/day) or placebo intake. Although high neuroticism was significantly related to a higher frequency of stressful life events and daily hassles, it did not interact with the 5-HTTLPR genotype on general past sleep quality. However, as expected, a 7 day period of tryptophan administration was exclusively associated with better sleep quality scores in the S'/S' genotype with high trait neuroticism. Current findings suggest that 5-HTTLPR does not directly interact with stress vulnerability in order to influence sleep quality. Instead, based on current and previous findings, it is suggested that the S'/S' 5-HTTLPR genotype promotes the risk for stress-related sleep disturbances because of an increased susceptibility to the depressogenic consequences of stress. Accordingly, by way of reducing depressive symptomatology, tryptophan augmentation may particularly improve sleep quality in stress-vulnerable individuals carrying the 5-HTTLPR S-allele. © The Author 2015. Published by Oxford University Press on behalf of CINP.

[Oxytocin, a mediator of anti-stress, well-being, social interaction, growth and healing].

Science.gov (United States)

Uvnas-Moberg, Kerstin; Petersson, Maria

2005-01-01

The neuroendocrine and physiological systems related to pain and stress have long been subjected to study. More recently, the corresponding systems promoting anti-stress and restoration have also come into focus. It is not only important to investigate the mechanisms underlying disease but also to examine the physiological and psychological mechanisms which protect and heal the body and soul. The nonapeptide oxytocin, originally known to stimulate labour and milk ejection, appears to play an important role in this regard. Oxytocin can induce anti-stress-like effects such as reduction of blood pressure and cortisol levels. It increases pain thresholds, exerts an anxiolytic-like effect and stimulates various types of positive social interaction. In addition, it promotes growth and healing. Repeated exposure to oxytocin causes long-lasting effects by influencing the activity of other transmitter systems, a pattern which makes oxytocin potentially clinically relevant. Oxytocin can be released by various types of non-noxious sensory stimulation, for example by touch and warmth. Ingestion of food triggers oxytocin release by activation of vagal afferents. Most likely, oxytocin can also be released by stimulation of other senses such as olfaction, as well as by certain types of sound and light. In addition, purely psychological mechanisms may trigger the release of oxytocin. This means that positive interaction involving touch and psychological support may be health-promoting. The social interaction of daily life, as well as a positive environment, continuously activate this system. In addition, various types of psychotherapy involving transfer of support, warmth and empathy are likely to induce similar effects, which thus contribute to the positive effects of these kinds of therapies.

Effects of stress and social support on mothers and premature and full-term infants.

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Crnic, K A; Greenberg, M T; Ragozin, A S; Robinson, N M; Basham, R B

1983-02-01

This study examined the relationships of stress and social support to maternal attitudes and early mother-infant interactive behavior. 52 mother-premature infant pairs and 53 mother-full-term infant pairs were seen for structured home interviews at 1 month, and behavioral interactions at 4 months. Maternal life stress, social support, life satisfaction, and satisfaction with parenting were assessed at the 1-month home visit. Although no group differences were found, both stress and support significantly predicted maternal attitudes at 1 month and interactive behavior at 4 months when data were pooled. Mothers with greater stress were less positive in their attitudes and behavior, while mothers with greater support were significantly more positive. Intimate support proved to have the most general positive effects. Additionally, social support moderated the adverse effects of stress on mother's life satisfaction and on several behavioral variables. Maternal social support was further found to have several significant effects on infant interactive behavior. Results are discussed in terms of the ecological significance of social support to parenting and infants' early development.

Clock genes × stress × reward interactions in alcohol and substance use disorders.

Science.gov (United States)

Perreau-Lenz, Stéphanie; Spanagel, Rainer

2015-06-01

Adverse life events and highly stressful environments have deleterious consequences for mental health. Those environmental factors can potentiate alcohol and drug abuse in vulnerable individuals carrying specific genetic risk factors, hence producing the final risk for alcohol- and substance-use disorders development. The nature of these genes remains to be fully determined, but studies indicate their direct or indirect relation to the stress hypothalamo-pituitary-adrenal (HPA) axis and/or reward systems. Over the past decade, clock genes have been revealed to be key-players in influencing acute and chronic alcohol/drug effects. In parallel, the influence of chronic stress and stressful life events in promoting alcohol and substance use and abuse has been demonstrated. Furthermore, the reciprocal interaction of clock genes with various HPA-axis components, as well as the evidence for an implication of clock genes in stress-induced alcohol abuse, have led to the idea that clock genes, and Period genes in particular, may represent key genetic factors to consider when examining gene × environment interaction in the etiology of addiction. The aim of the present review is to summarize findings linking clock genes, stress, and alcohol and substance abuse, and to propose potential underlying neurobiological mechanisms. Copyright © 2015 Elsevier Inc. All rights reserved.

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.

Interaction between early-life stress and FKBP5 gene variants in major depressive disorder and post-traumatic stress disorder: A systematic review and meta-analysis.

Science.gov (United States)

Wang, Qingzhong; Shelton, Richard C; Dwivedi, Yogesh

2018-01-01

Gene-environment interaction contributes to the risks of psychiatric disorders. Interactions between FKBP5 gene variants and early-life stress may enhance the risk not only for mood disorder, but also for a number of other behavioral phenotypes. The aim of the present study was to review and conduct a meta-analysis on the results from published studies examining interaction between FKBP5 gene variants and early-life stress and their associations with stress-related disorders such as major depression and PTSD. A literature search was conducted using PsychINFO and PubMed databases until May 2017. A total of 14 studies with a pooled total of 15109 participants met the inclusion criteria, the results of which were combined and a meta-analysis was performed using the differences in correlations as the effect measure. Based on literature, rs1360780, rs3800373, and rs9470080 SNPs were selected within the FKBP5 gene and systematic review was conducted. Based on the Comprehensive Meta-Analysis software, no publication bias was detected. Sensitivity analysis and credibility of meta-analysis results also indicated that the analyses were stable. The meta-analysis showed that individuals who carry T allele of rs1360780, C-allele of rs3800373 or T-allele of rs9470080 exposed to early-life trauma had higher risks for depression or PTSD. The effects of ethnicity, age, sex, and different stress measures were not examined due to limited sample size. These results provide strong evidence of interactions between FKBP5 genotypes and early-life stress, which could pose a significant risk factor for stress-associated disorders such as major depression and PTSD. Copyright © 2017 Elsevier B.V. All rights reserved.

Interaction between circadian rhythms and stress

Directory of Open Access Journals (Sweden)

C.E. Koch

2017-02-01

Full Text Available Life on earth has adapted to the day-night cycle by evolution of internal, so-called circadian clocks that adjust behavior and physiology to the recurring changes in environmental conditions. In mammals, a master pacemaker located in the suprachiasmatic nucleus (SCN of the hypothalamus receives environmental light information and synchronizes peripheral tissues and central non-SCN clocks to geophysical time. Regulatory systems such as the hypothalamus-pituitary-adrenal (HPA axis and the autonomic nervous system (ANS, both being important for the regulation of stress responses, receive strong circadian input. In this review, we summarize the interaction of circadian and stress systems and the resulting physiological and pathophysiological consequences. Finally, we critically discuss the relevance of rodent stress studies for humans, addressing complications of translational approaches and offering strategies to optimize animal studies from a chronobiological perspective.

Plant Water Stress Affects Interactions Between an Invasive and a Naturalized Aphid Species on Cereal Crops.

Science.gov (United States)

Foote, N E; Davis, T S; Crowder, D W; Bosque-Pérez, N A; Eigenbrode, S D

2017-06-01

In cereal cropping systems of the Pacific Northwestern United States (PNW), climate change is projected to increase the frequency of drought during summer months, which could increase water stress for crop plants. Yet, it remains uncertain how interactions between herbivore species are affected by drought stress. Here, interactions between two cereal aphids present in PNW cereal systems, Metopolophium festucae (Theobald) subsp. cerealium (a newly invasive species) and Rhopalosiphum padi L. (a naturalized species), were tested relative to wheat water stress. When aphids were confined in leaf cages on wheat, asymmetrical facilitation occurred; per capita fecundity of R. padi was increased by 46% when M. festucae cerealium was also present, compared to when only R. padi was present. Imposed water stress did not influence this interaction. When aphids were confined on whole wheat plants, asymmetrical competition occurred; cocolonization inhibited M. festucae cerealium population growth but did not affect R. padi population growth. Under conditions of plant water stress, however, the inhibitory effect of R. padi on M. festucae cerealium was not observed. We conclude that beneficial effects of cocolonization on R. padi are due to a localized plant response to M. festucae cerealium feeding, and that cocolonization of plants is likely to suppress M. festucae cerealium populations under ample water conditions, but not when plants are water stressed. This suggests that plant responses to water stress alter the outcome of competition between herbivore species, with implications for the structure of pest communities on wheat during periods of drought. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.

Social support attenuates the harmful effects of stress in healthy adult women.

Science.gov (United States)

Stein, Elizabeth R; Smith, Bruce W

2015-12-01

The purpose of this study was to test the hypothesis that social support buffers the effects of perceived stress on physical symptoms in healthy women. The study was conducted in the Southwest United States and data were collected from 2006 to 2010. Participants were 52 healthy adult women who completed a baseline questionnaire and a 21-day daily diary. Social support was assessed in the baseline questionnaire and perceived stress and physical symptoms were assessed in the daily diary. Multilevel analyses were used to predict both same day and next day physical symptoms from baseline social support and daily perceived stress. The hypotheses were supported when predicting both same and next day physical symptoms. For the same day, perceived stress and the social support × perceived stress interaction were both related to physical symptoms. For the next day, the social support × perceived stress interaction but not perceived stress was related to physical symptoms when controlling for previous day physical symptoms. The interactions were such that women higher in social support had smaller increases in same and next day physical symptoms on days of higher perceived stress than women lower in social support. Social support may buffer the effects of daily perceived stress on physical symptoms in healthy women. Future research should investigate what aspects and in what contexts social support may reduce the effects of perceived stress on physical symptoms and examine how social support may affect the development of long-term health problems through increases in daily physical symptoms. Copyright © 2015 Elsevier Ltd. All rights reserved.

Stress and Memory: Behavioral Effects and Neurobiological Mechanisms

Directory of Open Access Journals (Sweden)

M. Teresa Pinelo-Nava

2007-04-01

Full Text Available Stress is a potent modulator of learning and memory processes. Although there have been a few attempts in the literature to explain the diversity of effects (including facilitating, impairing, and lack of effects described for the impact of stress on memory function according to single classification criterion, they have proved insufficient to explain the whole complexity of effects. Here, we review the literature in the field of stress and memory interactions according to five selected classifying factors (source of stress, stressor duration, stressor intensity, stressor timing with regard to memory phase, and learning type in an attempt to develop an integrative model to understand how stress affects memory function. Summarizing on those conditions in which there was enough information, we conclude that high stress levels, whether intrinsic (triggered by the cognitive challenge or extrinsic (induced by conditions completely unrelated to the cognitive task, tend to facilitate Pavlovian conditioning (in a linear-asymptotic manner, while being deleterious for spatial/explicit information processing (which with regard to intrinsic stress levels follows an inverted U-shape effect. Moreover, after reviewing the literature, we conclude that all selected factors are essential to develop an integrative model that defines the outcome of stress effects in memory processes. In parallel, we provide a brief review of the main neurobiological mechanisms proposed to account for the different effects of stress in memory function. Glucocorticoids were found as a common mediating mechanism for both the facilitating and impairing actions of stress in different memory processes and phases. Among the brain regions implicated, the hippocampus, amygdala, and prefrontal cortex were highlighted as critical for the mediation of stress effects.

Interaction and notation of tone, stress and intonation in Ika Igbo ...

African Journals Online (AJOL)

This prominence has been proved by both acoustic and perceptual analyses. Hence in Ika, every intonation group (or tonal intonation group) has a nucleus (a stressed syllable) and it is this nucleus that bears the intonation. This is how stress interacts with intonation in Ika. Tone, on its part, is also affected by this interaction ...

Effects of stress on gastrointestinal function: interactions of neural and endocrine systems in mediating stress-induced intestinal dysfunction in rats

International Nuclear Information System (INIS)

Williams, C.L.

1987-01-01

The etiology of stress-induced intestinal dysfunction is completely unresolved, and the lack of an appropriate animal model has hindered studies of causality. We compared a number of stressors and their resultant effects on intestinal transit, a measure of the propulsive motor activity of the gut, in the rat. We found that the response of the intestine to stress, and the neural systems activated by stress, were dependent on the type and duration of stress, as well as the animal strain, and gender. We developed a model, acute wrapping restraint stress, to fully characterize the effects of stress on intestinal transit. Wrap restraint stress is a nonulcerogenic model in which rats are subjected to acute restraint by wrapping them in a harness of paper tape to restrict, but not prevent movement of the upper body and forelimbs. Transit was evaluated by the geometric center method, in which a radiomarker ( 51 Cr) is instilled directly into the proximal duodenum and proximal colon via a surgically placed intestinal cannula, in fasted, adult female Sprague Dawley rats

Stress, depressive status and telomere length: Does social interaction and coping strategy play a mediating role?

Science.gov (United States)

Liu, Jia Jia; Wei, Ya Bin; Forsell, Yvonne; Lavebratt, Catharina

2017-11-01

Telomeres have been reported to be shorter in individuals exposed to psychosocial stress and in those with depression. Since negative environmental stress is a risk factor for depression, the present study tested whether stressors in childhood (CA) and recent adulthood (NLE) predicted telomere attrition directly and/or indirectly through individuals' depressive status 3-6 years before TL measurement; and then if social interaction and coping strategies in adulthood influenced the relationship between depressive status and TL. Participants were 337 individuals with a recent depression diagnosis and 574 screened controls that derived from a longitudinal population-based cohort study conducted in Stockholm, Sweden. Relative TL was determined using qPCR. Relationships between the key variables stressors, depressive status, social interaction, coping strategies and TL were explored by path analysis in males and females, adjusting for age. The key variables were correlated in expected directions. In females, depressive status and age had direct negative effects on TL (p social interaction (p = 0.005) and the coping strategy worry (p = 0.005). In females, no mediation effect of social interaction and coping strategy was detected. Only little of the TL variation was explained by the models. The environmental stress information was limited. Our findings propose gender-specific paths from environmental stressors through depressive status, social interaction and coping strategy to TL. Copyright © 2017 Elsevier B.V. All rights reserved.

BDNF Val66Met polymorphism, life stress and depression: A meta-analysis of gene-environment interaction.

Science.gov (United States)

Zhao, Mingzhe; Chen, Lu; Yang, Jiarun; Han, Dong; Fang, Deyu; Qiu, Xiaohui; Yang, Xiuxian; Qiao, Zhengxue; Ma, Jingsong; Wang, Lin; Jiang, Shixiang; Song, Xuejia; Zhou, Jiawei; Zhang, Jian; Chen, Mingqi; Qi, Dong; Yang, Yanjie; Pan, Hui

2018-02-01

Depression is thought to be multifactorial in etiology, including genetic and environmental components. While a number of gene-environment interaction studies have been carried out, meta-analyses are scarce. The present meta-analysis aimed to quantify evidence on the interaction between brain-derived neurotrophic factor (BDNF) Val66Met polymorphism and stress in depression. Included were 31 peer-reviewed with a pooled total of 21060 participants published before October 2016 and literature searches were conducted using PubMed, Wolters Kluwer, Web of Science, EBSCO, Elsevier Science Direct and Baidu Scholar databases. The results indicated that the Met allele of BDNF Val66Met polymorphism significantly moderated the relationship between stress and depression (Z=2.666, p = 0.003). The results of subgroup analysis concluded that stressful life events and childhood adversity separately interacted with the Met allele of BDNF Val66Met polymorphism in depression (Z = 2.552, p = 0.005; Z = 1.775, p = 0.03). The results could be affected by errors or bias in primary studies which had small sample sizes with relatively lower statistic power. We could not estimate how strong the interaction effect between gene and environment was. We found evidence that supported the hypothesis that BDNF Val66Met polymorphism moderated the relationship between stress and depression, despite the fact that many included individual studies did not show this effect. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of a Dyadic Music Therapy Intervention on Parent-Child Interaction, Parent Stress, and Parent-Child Relationship in Families with Emotionally Neglected Children

DEFF Research Database (Denmark)

Jacobsen, Stine Lindahl; H. McKinney, Cathy; Holck, Ulla

2014-01-01

of this study was to investigate the effect of a dyadic music therapy intervention on observed parent-child interaction (mutual attunement, nonverbal communication, emotional parental response), self-reported parenting stress, and self-reported parent-child relationship in families at risk and families...... significantly improved their nonverbal communication and mutual attunement. Similarly, parents who participated in dyadic music therapy reported themselves to be significantly less stressed by the mood of the child and to significantly improve their parent-child relationship in terms of being better at talking......-perceived autonomy, attachment, and parental competence. Conclusions: The dyadic music therapy intervention examined in this study improved emotional communication between parent and child and interaction after 6 to 10 sessions and can be considered as a viable treatment alternative or supplement for families...

Effects of economic interactions on credit risk

International Nuclear Information System (INIS)

Hatchett, J P L; Kuehn, R

2006-01-01

We study a credit-risk model which captures effects of economic interactions on a firm's default probability. Economic interactions are represented as a functionally defined graph, and the existence of both cooperative and competitive business relations is taken into account. We provide an analytic solution of the model in a limit where the number of business relations of each company is large, but the overall fraction of the economy with which a given company interacts may be small. While the effects of economic interactions are relatively weak in typical (most probable) scenarios, they are pronounced in situations of economic stress, and thus lead to a substantial fattening of the tails of loss distributions in large loan portfolios. This manifests itself in a pronounced enhancement of the value at risk computed for interacting economies in comparison with their non-interacting counterparts

Treadmill exercise alleviates stress-induced impairment of social interaction through 5-hydroxytryptamine 1A receptor activation in rats.

Science.gov (United States)

Kim, Tae-Woon; Lim, Baek-Vin; Kim, Kijeong; Seo, Jin-Hee; Kim, Chang-Ju

2015-08-01

Brain-derived neurotrophic factor (BDNF) and its receptors tyrosine kinase B (trkB), and cyclic adenosine monophosphate response element binding protein (CREB) have been suggested as the neurobiological risk factors causing depressive disorder. Serotonin (5-hydroxytryptamine, 5-HT) plays an important role in the pathogenesis of depression. We in-vestigated the effect of treadmill exercise on social interaction in relation with BDNF and 5-HT expressions following stress in rats. Stress was induced by applying inescapable 0.2 mA electric foot shock to the rats for 7 days. The rats in the exercise groups were forced to run on a motorized treadmill for 30 min once a day for 4 weeks. Social interaction test and western blot for BDNF, TrkB, pCREB, and 5-HT1A in the hippocampus were performed. The results indicate that the spend time with unfamiliar partner was decreased by stress, in contrast, treadmill exercise increased the spending time in the stress-induced rats. Expressions of BDNF, TrkB, and pCREB were decreased by stress, in contrast, treadmill exercise enhanced expressions of BDNF, TrkB, and pCREB in the stress-induced rats. In addition, 5-HT1A receptor expression was de-creased by stress, in contrast, treadmill exercise enhanced 5-HT1A expression in the stress-induced rats. In the present study, treadmill exercise alleviated stress-induced social interaction impairment through enhancing hippocampal plasticity and serotonergic function in the hippocampus. These effects of treadmill exercise are achieved through 5-HT1A receptor activation.

Developmental post-natal stress can alter the effects of pre-natal stress on the adult redox balance.

Science.gov (United States)

Marasco, Valeria; Spencer, Karen A; Robinson, Jane; Herzyk, Pawel; Costantini, David

2013-09-15

Across diverse vertebrate taxa, stressful environmental conditions during development can shape phenotypic trajectories of developing individuals, which, while adaptive in the short-term, may impair health and survival in adulthood. Regardless, the long-lasting benefits or costs of early life stress are likely to depend on the conditions experienced across differing stages of development. Here, we used the Japanese quail (Coturnix coturnix japonica) to experimentally manipulate exposure to stress hormones in developing individuals. We tested the hypothesis that interactions occurring between pre- and post-natal developmental periods can induce long-term shifts on the adult oxidant phenotype in non-breeding sexually mature individuals. We showed that early life stress can induce long-term alterations in the basal antioxidant defences. The magnitude of these effects depended upon the timing of glucocorticoid exposure and upon interactions between the pre- and post-natal stressful stimuli. We also found differences among tissues with stronger effects in the erythrocytes than in the brain in which the long-term effects of glucocorticoids on antioxidant biomarkers appeared to be region-specific. Recent experimental work has demonstrated that early life exposure to stress hormones can markedly reduce adult survival (Monaghan et al., 2012). Our results suggest that long-term shifts in basal antioxidant defences might be one of the potential mechanisms driving such accelerated ageing processes and that post-natal interventions during development may be a potential tool to shape the effects induced by pre-natally glucococorticoid-exposed phenotypes. Copyright © 2013 Elsevier Inc. All rights reserved.

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

Science.gov (United States)

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.

Evidence of an IFN-γ by early life stress interaction in the regulation of amygdala reactivity to emotional stimuli.

Science.gov (United States)

Redlich, Ronny; Stacey, David; Opel, Nils; Grotegerd, Dominik; Dohm, Katharina; Kugel, Harald; Heindel, Walter; Arolt, Volker; Baune, Bernhard T; Dannlowski, Udo

2015-12-01

Since numerous studies have found that exposure to early life stress leads to increased peripheral inflammation and psychiatric disease, it is thought that peripheral immune activation precedes and possibly mediates the onset of stress-associated psychiatric disease. Despite early studies, IFNγ has received little attention relative to other inflammatory cytokines in the context of the pathophysiology of affective disorders. Neuroimaging endophenotypes have emerged recently as a promising means of elucidating these types of complex relationships including the modeling of the interaction between environmental factors and genetic predisposition. Here we investigate the GxE relationship between early-life stress and genetic variants of IFNγ on emotion processing. To investigate the impact of the relationship between genetic variants of IFNγ (rs1861494, rs2069718, rs2430561) and early life stress on emotion processing, a sample of healthy adults (n=409) undergoing an emotional faces paradigm in an fMRI study were genotyped and analysed. Information on early life stress was obtained via Childhood Trauma Questionnaire (CTQ). A positive association between early life stress and amygdala reactivity was found. Specifically, the main effect of genotype of rs1861494 on amygdala reactivity indicates a higher neural response in C allele carriers compared to T homozygotes, while we did not find main effects of rs2069718 and rs2430561. Importantly, interaction analyses revealed a specific interaction between IFNγ genotype (rs1861494) and early life stress affecting amygdala reactivity to emotional faces, resulting from a positive association between CTQ scores and amygdala reactivity in C allele carriers while this association was absent in T homozygotes. Our findings indicate that firstly the genetic variant of IFNγ (rs1861494) is involved with the regulation of amygdala reactivity to emotional stimuli and secondly, that this genetic variant moderates effects of early life

Experimental evaluation of the interaction effect between plastic and creep deformation

International Nuclear Information System (INIS)

Ikegami, K.; Niitsu, Y.

1985-01-01

An experimental study of plasticity-creep interaction effects is reported. The combined stress tests are performed on thin wall tubular specimens of SUS 304 stainless steel at room temperature and high temperature (600 0 C). The plastic behaviors subsequent to creep pre-strain and creep behaviors subsequent to plastic pre-strain are obtained for loading along straight stress paths with a corner. The inelastic behaviors including both plastic and creep deformations are experimentally investigated. The interaction effects between plastic and creep deformations are quantitatively estimated with the equi-plastic strain surface. (author)

Effects of a dyadic music therapy intervention on parent-child interaction, parent stress, and parent-child relationship in families with emotionally neglected children: a randomized controlled trial.

Science.gov (United States)

Jacobsen, Stine L; McKinney, Cathy H; Holck, Ulla

2014-01-01

Work with families and families at risk within the field of music therapy have been developing for the last decade. To diminish risk for unhealthy child development, families with emotionally neglected children need help to improve their emotional communication and develop healthy parent-child interactions. While some researchers have investigated the effect of music therapy on either the parent or the child, no study has investigated the effect of music therapy on the observed interaction between the parent and child within the field of child protection. The purpose of this study was to investigate the effect of a dyadic music therapy intervention on observed parent-child interaction (mutual attunement, nonverbal communication, emotional parental response), self-reported parenting stress, and self-reported parent-child relationship in families at risk and families with emotionally neglected children, ages 5-12 years. This was a randomized controlled trial study conducted at a family care center in Denmark. Eighteen parent-child dyads were randomly assigned to receive 10 weekly music therapy sessions with a credentialed music therapist (n = 9) or treatment as usual (n = 9). Observational measures for parent-child interaction, self-reported measures for parenting stress and parent-child relationship were completed at baseline and 4 months post-baseline assessment. Results of the study showed that dyads who received music therapy intervention significantly improved their nonverbal communication and mutual attunement. Similarly, parents who participated in dyadic music therapy reported themselves to be significantly less stressed by the mood of the child and to significantly improve their parent-child relationship in terms of being better at talking to and understanding their children than parents who did not receive music therapy. Both groups significantly improved in terms of increased positive and decreased negative emotional parental response, parenting stress and

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.

On the interaction of UV-B radiation (280-315 mm) with water stress in crop plants

International Nuclear Information System (INIS)

Balakumar, T.; Vincent, V.H.B.; Paliwal, K.

1993-01-01

Cowpea (Vigna unguiculata L. Walp.) seedlings (3-day-old) were subjected to 4 kinds of experimental treatments: (1) control without exposure to any stress (-D-UV), (2) moderate water stress with no UV-B irradiation (+D-UV), (3) no water stress but exposure to UV-B radiation (-D+UV), and (4) moderate water stress and exposure to UV-B (+D+UV). UV-B and drought stress in the combined form elicited beneficial effects on the morphological and growth characteristics, and a few additive inhibitory effects in some functional processes. An increase in the specific leaf weight (SLW) was observed in the combination of stresses, which could be a defence mechanism against UV-B. The combination of stresses promoted the synthesis of anthocyanins and phenolic compounds. The responses of plants to the combination of stresses indicate that during simultaneous exposure of plants to multiple stresses, one form of stress could minimize the damage by the other. The enhancement of superoxide dismutase (SOD) and catalase activities appear to serve as acclimation mechanisms to scavenge the toxic, free radicals of oxygen produced under stress conditions. However, the inhibition in nitrate metabolism was greater in the combined stresses than in either of the stresses imposed separately. The results of this study illustrate that the interaction of stresses during simultaneous multiple stress conditions brings out certain beneficial effects. (author)

Interaction Between 2 Nutraceutical Treatments and Host Immune Status in the Pediatric Critical Illness Stress-Induced Immune Suppression Comparative Effectiveness Trial.

Science.gov (United States)

Carcillo, Joseph A; Dean, J Michael; Holubkov, Richard; Berger, John; Meert, Kathleen L; Anand, Kanwaljeet J S; Zimmerman, Jerry J; Newth, Christopher J L; Harrison, Rick; Burr, Jeri; Willson, Douglas F; Nicholson, Carol; Bell, Michael J; Berg, Robert A; Shanley, Thomas P; Heidemann, Sabrina M; Dalton, Heidi; Jenkins, Tammara L; Doctor, Allan; Webster, Angie; Tamburro, Robert F

2017-11-01

The pediatric Critical Illness Stress-induced Immune Suppression (CRISIS) trial compared the effectiveness of 2 nutraceutical supplementation strategies and found no difference in the development of nosocomial infection and sepsis in the overall population. We performed an exploratory post hoc analysis of interaction between nutraceutical treatments and host immune status related to the development of nosocomial infection/sepsis. Children from the CRISIS trial were analyzed according to 3 admission immune status categories marked by decreasing immune competence: immune competent without lymphopenia, immune competent with lymphopenia, and previously immunocompromised. The comparative effectiveness of the 2 treatments was analyzed for interaction with immune status category. There were 134 immune-competent children without lymphopenia, 79 previously immune-competent children with lymphopenia, and 27 immunocompromised children who received 1 of the 2 treatments. A significant interaction was found between treatment arms and immune status on the time to development of nosocomial infection and sepsis ( P patient characteristic.

Effect of normal stress under an excitation in poroelastic flat slabs

African Journals Online (AJOL)

user

Biot's poroelastic theory is employed to investigate stresses under an ... Keywords: Flat slab, radial normal stress, pervious surface, impervious ... warranted, because of above mentioned applications. ...... M.Tajuddin, and G. Narayan Reddy, Effect of boundaries on the dynamic interaction of a liquid filled porous layer and a.

Environmental Stress Responses and Biological Interactions Investigated in the Drosophila Model System

DEFF Research Database (Denmark)

Ørsted, Michael

on their ability to respond on a behavioral, physiological, morphological and/or evolutionary level according to the environmental cues. At the same time, if populations are small and fragmented, and have limited gene flow, environmental change and environmental stress might interact with intrinsic genetic stress...... such as inbreeding and genetic drift, which can exacerbate the effects of one or more environmental stresses. Furthermore, inbred populations often have low genetic variation that might constrain evolutionary responses to rapidly changing environments. This thesis investigates how, and to what extent, insect model......When organisms are faced with changes in their environment, they are forced to respond, if they are to maintain optimal function. Especially ectotherms must deal with environmental changes in e.g. temperature on a regular basis, and thus their survival and reproductive success depend...

Anxiety, affect, self-esteem, and stress: mediation and moderation effects on depression.

Science.gov (United States)

Nima, Ali Al; Rosenberg, Patricia; Archer, Trevor; Garcia, Danilo

2013-01-01

Mediation analysis investigates whether a variable (i.e., mediator) changes in regard to an independent variable, in turn, affecting a dependent variable. Moderation analysis, on the other hand, investigates whether the statistical interaction between independent variables predict a dependent variable. Although this difference between these two types of analysis is explicit in current literature, there is still confusion with regard to the mediating and moderating effects of different variables on depression. The purpose of this study was to assess the mediating and moderating effects of anxiety, stress, positive affect, and negative affect on depression. Two hundred and two university students (males  = 93, females  = 113) completed questionnaires assessing anxiety, stress, self-esteem, positive and negative affect, and depression. Mediation and moderation analyses were conducted using techniques based on standard multiple regression and hierarchical regression analyses. The results indicated that (i) anxiety partially mediated the effects of both stress and self-esteem upon depression, (ii) that stress partially mediated the effects of anxiety and positive affect upon depression, (iii) that stress completely mediated the effects of self-esteem on depression, and (iv) that there was a significant interaction between stress and negative affect, and between positive affect and negative affect upon depression. The study highlights different research questions that can be investigated depending on whether researchers decide to use the same variables as mediators and/or moderators.

Environmental Maternal Effects Mediate the Resistance of Maritime Pine to Biotic Stress

Science.gov (United States)

Vivas, María; Zas, Rafael; Sampedro, Luis; Solla, Alejandro

2013-01-01

The resistance to abiotic stress is increasingly recognised as being impacted by maternal effects, given that environmental conditions experienced by parent (mother) trees affect stress tolerance in offspring. We hypothesised that abiotic environmental maternal effects may also mediate the resistance of trees to biotic stress. The influence of maternal environment and maternal genotype and the interaction of these two factors on early resistance of Pinus pinaster half-sibs to the Fusarium circinatum pathogen was studied using 10 mother genotypes clonally replicated in two contrasting environments. Necrosis length of infected seedlings was 16% shorter in seedlings grown from favourable maternal environment seeds than in seedlings grown from unfavourable maternal environment seeds. Damage caused by F. circinatum was mediated by maternal environment and maternal genotype, but not by seed mass. Mechanisms unrelated to seed provisioning, perhaps of epigenetic nature, were probably involved in the transgenerational plasticity of P. pinaster, mediating its resistance to biotic stress. Our findings suggest that the transgenerational resistance of pines due to an abiotic stress may interact with the defensive response of pines to a biotic stress. PMID:23922944

Environmental maternal effects mediate the resistance of maritime pine to biotic stress.

Directory of Open Access Journals (Sweden)

María Vivas

Full Text Available The resistance to abiotic stress is increasingly recognised as being impacted by maternal effects, given that environmental conditions experienced by parent (mother trees affect stress tolerance in offspring. We hypothesised that abiotic environmental maternal effects may also mediate the resistance of trees to biotic stress. The influence of maternal environment and maternal genotype and the interaction of these two factors on early resistance of Pinus pinaster half-sibs to the Fusarium circinatum pathogen was studied using 10 mother genotypes clonally replicated in two contrasting environments. Necrosis length of infected seedlings was 16% shorter in seedlings grown from favourable maternal environment seeds than in seedlings grown from unfavourable maternal environment seeds. Damage caused by F. circinatum was mediated by maternal environment and maternal genotype, but not by seed mass. Mechanisms unrelated to seed provisioning, perhaps of epigenetic nature, were probably involved in the transgenerational plasticity of P. pinaster, mediating its resistance to biotic stress. Our findings suggest that the transgenerational resistance of pines due to an abiotic stress may interact with the defensive response of pines to a biotic stress.

Sport and Nutrition Education Interaction on Stress

Science.gov (United States)

Ozturk, Mehmet Ertugrul

2015-01-01

The aim of the study was to determine sport and nutrition education interaction on stress. Three groups were selected for the study: control, single treatment and social treatment under nutrition treatment, too. The groups that were under nutrition treatments should have information about the nutrition resources. This experiment was done for two…

The Interacting Effect of the BDNF Val66Met Polymorphism and Stressful Life Events on Adolescent Depression Is Not an Artifact of Gene-Environment Correlation: Evidence from a Longitudinal Twin Study

Science.gov (United States)

Chen, Jie; Li, Xinying; McGue, Matt

2013-01-01

Background: Confounding introduced by gene-environment correlation (rGE) may prevent one from observing a true gene-environment interaction (G × E) effect on psychopathology. The present study investigated the interacting effect of the BDNF Val66Met polymorphism and stressful life events (SLEs) on adolescent depression while controlling for the…

Critical shear stress produced by interaction of edge dislocation with ...

Indian Academy of Sciences (India)

According to the Mott and Nabarro's model, the contribution to the critical shear stress of the material caused by the interaction between edge dislocations and nanoscale cylindrical inhomogeneities with interface stresses is obtained. The influence of the radius and the volume fraction of the inhomogeneity as well as the ...

Does plant-Microbe interaction confer stress tolerance in plants: A review?

Science.gov (United States)

Kumar, Akhilesh; Verma, Jay Prakash

2018-03-01

The biotic and abiotic stresses are major constraints for crop yield, food quality and global food security. A number of parameters such as physiological, biochemical, molecular of plants are affected under stress condition. Since the use of inorganic fertilizers and pesticides in agriculture practices cause degradation of soil fertility and environmental pollutions. Hence it is necessary to develop safer and sustainable means for agriculture production. The application of plant growth promoting microbes (PGPM) and mycorrhizal fungi enhance plant growth, under such conditions. It offers an economically fascinating and ecologically sound ways for protecting plants against stress condition. PGPM may promote plant growth by regulating plant hormones, improve nutrition acquisition, siderophore production and enhance the antioxidant system. While acquired systemic resistance (ASR) and induced systemic resistance (ISR) effectively deal with biotic stress. Arbuscular mycorrhiza (AM) enhance the supply of nutrients and water during stress condition and increase tolerance to stress. This plant-microbe interaction is vital for sustainable agriculture and industrial purpose, because it depends on biological processes and replaces conventional agriculture practices. Therefore, microbes may play a key role as an ecological engineer to solve environmental stress problems. So, it is a feasible and potential technology in future to feed global population at available resources with reduced impact on environmental quality. In this review, we have attempted to explore about abiotic and biotic stress tolerant beneficial microorganisms and their modes of action to enhance the sustainable agricultural production. Copyright © 2017 Elsevier GmbH. All rights reserved.

The serotonin transporter gene polymorphism 5-HTTLPR moderates the effects of stress on attention-deficit/hyperactivity disorder.

Science.gov (United States)

van der Meer, Dennis; Hartman, Catharina A; Richards, Jennifer; Bralten, Janita B; Franke, Barbara; Oosterlaan, Jaap; Heslenfeld, Dirk J; Faraone, Stephen V; Buitelaar, Jan K; Hoekstra, Pieter J

2014-12-01

The role of the serotonin transporter gene polymorphism 5-HTTLPR in attention-deficit/hyperactivity disorder (ADHD) is unclear. Heterogeneity of findings may be explained by gene-environment interactions (GxE), as it has been suggested that S-allele carriers are more reactive to psychosocial stress than L-allele homozygotes. This study aimed to investigate whether 5-HTTLPR genotype moderates the effects of stress on ADHD in a multisite prospective ADHD cohort study. 5-HTTLPR genotype, as well as the number of stressful life events in the past 5 years and ongoing long-term difficulties, was determined in 671 adolescents and young adults with ADHD, their siblings, and healthy controls (57.4% male, average age 17.3 years). Linear mixed models, accounting for family relatedness, were applied to investigate the effects of genotype, experienced stress, and their interaction on ADHD severity at time point T2, while controlling for ADHD severity at T1 (mean follow-up time 5.9 years) and for comorbid internalizing problems at T2. The interaction between genotype and stress significantly predicted ADHD severity at T2 (p = .006), which was driven by the effect on hyperactivity-impulsivity (p = .004). Probing of the interaction effect made clear that S-allele carriers had a significantly more positive correlation between stress and ADHD severity than L-allele homozygotes. The results show that the interaction between 5-HTTLPR and stress is a mechanism involved particularly in the hyperactivity/impulsivity dimension of ADHD, and that this is independent of comorbid internalizing problems. Further research into the neurobiological mechanisms underlying this interaction effect is warranted. © 2014 The Authors. Journal of Child Psychology and Psychiatry. © 2014 Association for Child and Adolescent Mental Health.

The Moderating Effect of Interaction Avoidance Between Abusive Supervision and Subordinates' Job Promotions.

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Peltokorpi, Vesa

2017-10-03

While abusive supervision is shown to have negative stress-related effects on targets, less is known about the factors capable of mitigating these negative effects and their career-related outcomes. In this paper, we drew on the transactional model of stress and coping (Lazarus & Folkman, 1986) and the upward mobility theory (Turner, 1960) to explore the moderating effect of subordinates' interaction avoidance between abusive supervision and job promotions. To test this moderating effect, we collected data from 604 full-time employees at three points in time over a 12-month time period in Japan. The findings suggest that interaction avoidance moderates the relationship between abusive supervision and promotions, such that this relationship will be less negative as interaction avoidance increases.

Anxiety, affect, self-esteem, and stress: mediation and moderation effects on depression.

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Ali Al Nima

Full Text Available Mediation analysis investigates whether a variable (i.e., mediator changes in regard to an independent variable, in turn, affecting a dependent variable. Moderation analysis, on the other hand, investigates whether the statistical interaction between independent variables predict a dependent variable. Although this difference between these two types of analysis is explicit in current literature, there is still confusion with regard to the mediating and moderating effects of different variables on depression. The purpose of this study was to assess the mediating and moderating effects of anxiety, stress, positive affect, and negative affect on depression.Two hundred and two university students (males  = 93, females  = 113 completed questionnaires assessing anxiety, stress, self-esteem, positive and negative affect, and depression. Mediation and moderation analyses were conducted using techniques based on standard multiple regression and hierarchical regression analyses.The results indicated that (i anxiety partially mediated the effects of both stress and self-esteem upon depression, (ii that stress partially mediated the effects of anxiety and positive affect upon depression, (iii that stress completely mediated the effects of self-esteem on depression, and (iv that there was a significant interaction between stress and negative affect, and between positive affect and negative affect upon depression.The study highlights different research questions that can be investigated depending on whether researchers decide to use the same variables as mediators and/or moderators.

Anxiety, Affect, Self-Esteem, and Stress: Mediation and Moderation Effects on Depression

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Nima, Ali Al; Rosenberg, Patricia; Archer, Trevor; Garcia, Danilo

2013-01-01

Background Mediation analysis investigates whether a variable (i.e., mediator) changes in regard to an independent variable, in turn, affecting a dependent variable. Moderation analysis, on the other hand, investigates whether the statistical interaction between independent variables predict a dependent variable. Although this difference between these two types of analysis is explicit in current literature, there is still confusion with regard to the mediating and moderating effects of different variables on depression. The purpose of this study was to assess the mediating and moderating effects of anxiety, stress, positive affect, and negative affect on depression. Methods Two hundred and two university students (males  = 93, females  = 113) completed questionnaires assessing anxiety, stress, self-esteem, positive and negative affect, and depression. Mediation and moderation analyses were conducted using techniques based on standard multiple regression and hierarchical regression analyses. Main Findings The results indicated that (i) anxiety partially mediated the effects of both stress and self-esteem upon depression, (ii) that stress partially mediated the effects of anxiety and positive affect upon depression, (iii) that stress completely mediated the effects of self-esteem on depression, and (iv) that there was a significant interaction between stress and negative affect, and between positive affect and negative affect upon depression. Conclusion The study highlights different research questions that can be investigated depending on whether researchers decide to use the same variables as mediators and/or moderators. PMID:24039896

Evaluation of crack interaction effect for in-plane surface cracks using elastic finite element analyses

International Nuclear Information System (INIS)

Huh, Nam Su; Choi, Suhn; Park, Keun Bae; Kim, Jong Min; Choi, Jae Boong; Kim, Young Jin

2008-01-01

The crack-tip stress fields and fracture mechanics assessment parameters, such as the elastic stress intensity factor and the elastic-plastic J-integral, for a surface crack can be significantly affected by adjacent cracks. Such a crack interaction effect due to multiple cracks can magnify the fracture mechanics assessment parameters. There are many factors to be considered, for instance the relative distance between adjacent cracks, crack shape and loading condition, to quantify a crack interaction effect on the fracture mechanics assessment parameters. Thus, the current guidance on a crack interaction effect (crack combination rule), including ASME Sec. XI, BS7910, British Energy R6 and API RP579, provide different rules for combining multiple surface cracks into a single surface crack. The present paper investigates a crack interaction effect by evaluating the elastic stress intensity factor of adjacent surface cracks in a plate along the crack front through detailed 3-dimensional elastic finite element analyses. The effects of the geometric parameters, the relative distance between cracks and the crack shape, on the stress intensity factor are systematically investigated. As for the loading condition, only axial tension is considered. Based on the elastic finite element results, the acceptability of the crack combination rules provided in the existing guidance was investigated, and the relevant recommendations on a crack interaction for in-plane surface cracks in a plate were discussed

Soil-Plant-Microbe Interactions in Stressed Agriculture Management: A Review

Institute of Scientific and Technical Information of China (English)

Shobhit Raj VIMAL; Jay Shankar SINGH; Naveen Kumar ARORA; Surendra SINGH

2017-01-01

The expected rise in temperature and decreased precipitation owing to climate change and unabated anthropogenic activities add complexity and uncertainty to agro-industry.The impact of soil nutrient imbalance,mismanaged use of chemicals,high temperature,flood or drought,soil salinity,and heavy metal pollutions,with regard to food security,is increasingly being explored worldwide.This review describes the role of soil-plant-microbe interactions along with organic manure in solving stressed agriculture problems.Beneficial microbes associated with plants are known to stimulate plant growth and enhance plant resistance to biotic (diseases) and abiotic (salinity,drought,pollutions,etc.) stresses.The plant growth-promoting rhizobacteria (PGPR) and mycorrhizae,a key component of soil microbiota,could play vital roles in the maintenance of plant fitness and soil health under stressed environments.The application of organic manure as a soil conditioner to stressed soils along with suitable microbial strains could further enhance the plant-microbe associations and increase the crop yield.A combination of plant,stress-tolerant microbe,and organic amendment represents the tripartite association to offer a favourable environment to the proliferation of beneficial rhizosphere microbes that in turn enhance the plant growth performance in disturbed agro-ecosystem.Agriculture land use patterns with the proper exploitation of plant-microbe associations,with compatible beneficial microbial agents,could be one of the most effective strategies in the management of the concerned agriculture lands owing to climate change resilience.However,the association of such microbes with plants for stressed agriculture management still needs to be explored in greater depth.

Complex modulation by stress of the effect of seizures on long term potentiation in mouse hippocampal slices.

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Maggio, Nicola; Shavit Stein, Efrat; Segal, Menahem

2017-08-01

Stress has a profound effect on ability to express neuronal plasticity, learning, and memory. Likewise, epileptic seizures lead to massive changes in brain connectivity, and in ability to undergo long term changes in reactivity to afferent stimulation. In this study, we analyzed possible long lasting interactions between a stressful experience and reactivity to pilocarpine, on the ability to produce long term potentiation (LTP) in a mouse hippocampus. Pilocarpine lowers paired pulse potentiation as well as LTP in CA1 region of the mouse hippocampal slice. When stress experience precedes exposure to pilocarpine, it protects the brain from the lasting effect of pilocarpine. When stress follows pilocarpine, it exacerbates the effect of the drug, to produce a long lasting reduction in LTP. These changes are accompanied by a parallel change in blood corticosterone level. A single exposure to selective mineralo- or gluco-corticosterone (MR and GR, respectively) agonists and antagonists can mimic the stress effects, indicating that GR's underlie the lasting detrimental effects of stress whereas MRs are instrumental in counteracting the effects of stress. These studies open a new avenue of understanding of the interactive effects of stress and epileptic seizures on brain plasticity. © 2017 Wiley Periodicals, Inc.

Interactome of Obesity: Obesidome : Genetic Obesity, Stress Induced Obesity, Pathogenic Obesity Interaction.

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Geronikolou, Styliani A; Pavlopoulou, Athanasia; Cokkinos, Dennis; Chrousos, George

2017-01-01

Obesity is a chronic disease of increasing prevalence reaching epidemic proportions. Genetic defects as well as epigenetic effects contribute to the obesity phenotype. Investigating gene (e.g. MC4R defects)-environment (behavior, infectious agents, stress) interactions is a relative new field of great research interest. In this study, we have made an effort to create an interactome (henceforth referred to as "obesidome"), where extrinsic stressors response, intrinsic predisposition, immunity response to inflammation and autonomous nervous system implications are integrated. These pathways are presented in one interactome network for the first time. In our study, obesity-related genes/gene products were found to form a complex interactions network.

Effects of work-related sleep restriction on acute physiological and psychological stress responses and their interactions: A review among emergency service personnel

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Alexander Wolkow

2015-04-01

Full Text Available Emergency work can expose personnel to sleep restriction. Inadequate amounts of sleep can negatively affect physiological and psychological stress responses. This review critiqued the emergency service literature (e.g., firefighting, police/law enforcement, defense forces, ambulance/paramedic personnel that has investigated the effect of sleep restriction on hormonal, inflammatory and psychological responses. Furthermore, it investigated if a psycho-physiological approach can help contextualize the significance of such responses to assist emergency service agencies monitor the health of their personnel. The available literature suggests that sleep restriction across multiple work days can disrupt cytokine and cortisol levels, deteriorate mood and elicit simultaneous physiological and psychological responses. However, research concerning the interaction between such responses is limited and inconclusive. Therefore, it is unknown if a psycho-physiological relationship exists and as a result, it is currently not feasible for agencies to monitor sleep restriction related stress based on psycho- physiological interactions. Sleep restriction does however, appear to be a major stressor contributing to physiological and psychological responses and thus, warrants further investigation.

Partial genetic deletion of neuregulin 1 and adolescent stress interact to alter NMDA receptor binding in the medial prefrontal cortex

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Tariq Waseem Chohan

2014-09-01

Full Text Available Schizophrenia is thought to arise due to a complex interaction between genetic and environmental factors during early neurodevelopment. We have recently shown that partial genetic deletion of the schizophrenia susceptibility gene neuregulin 1 (Nrg1 and adolescent stress interact to disturb sensorimotor gating, neuroendocrine activity and dendritic morphology in mice. Both stress and Nrg1 may have converging effects upon N-methyl-D-aspartate receptors (NMDARs which are implicated in the pathogenesis of schizophrenia, sensorimotor gating and dendritic spine plasticity. Using an identical repeated restraint stress paradigm to our previous study, here we determined NMDAR binding across various brain regions in adolescent Nrg1 heterozygous (HET and wild-type (WT mice using [3H] MK-801 autoradiography. Repeated restraint stress increased NMDAR binding in the ventral part of the lateral septum (LSV and the dentate gyrus (DG of the hippocampus irrespective of genotype. Partial genetic deletion of Nrg1 interacted with adolescent stress to promote an altered pattern of NMDAR binding in the infralimbic (IL subregion of the medial prefrontal cortex. In the IL, whilst stress tended to increase NMDAR binding in WT mice, it decreased binding in Nrg1 HET mice. However in the DG, stress selectively increased the expression of NMDAR binding in Nrg1 HET mice but not WT mice. These results demonstrate a Nrg1-stress interaction during adolescence on NMDAR binding in the medial prefrontal cortex.

Oxidative stress and maternal obesity: feto-placental unit interaction.

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Malti, N; Merzouk, H; Merzouk, S A; Loukidi, B; Karaouzene, N; Malti, A; Narce, M

2014-06-01

To determine oxidative stress markers in maternal obesity during pregnancy and to evaluate feto-placental unit interaction, especially predictors of fetal metabolic alterations. 40 obese pregnant women (prepregnancy BMI > 30 kg/m²) were compared to 50 control pregnant women. Maternal, cord blood and placenta samples were collected at delivery. Biochemical parameters (total cholesterol and triglycerides) and oxidative stress markers (malondialdehyde, carbonyl proteins, superoxide anion expressed as reduced Nitroblue Tetrazolium, nitric oxide expressed as nitrite, reduced glutathione, catalase, superoxide dismutase) were assayed by biochemical methods. Maternal, fetal and placental triglyceride levels were increased in obese group compared to control. Maternal malondialdehyde, carbonyl proteins, nitric oxide and superoxide anion levels were high while reduced glutathione concentrations and superoxide dismutase activity were low in obesity. In the placenta and in newborns of these obese mothers, variations of redox balance were also observed indicating high oxidative stress. Maternal and placental interaction constituted a strong predictor of fetal redox variations in obese pregnancies. Maternal obesity compromised placental metabolism and antioxidant status which strongly impacted fetal redox balance. Oxidative stress may be one of the key downstream mediators that initiate programming of the offspring. Maternal obesity is associated with metabolic alterations and dysregulation of redox balance in the mother-placenta - fetus unit. These perturbations could lead to maternal and fetal complications and should be carefully considered. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

Effect of plastic behaviour of steels during martensitic transformation on quenching stress initiation

International Nuclear Information System (INIS)

Denis-Judlin, Sabine

1980-01-01

This research thesis reports the study of the effects of a steel martensitic transformation on the mechanisms producing internal stresses during quench. After having reported a bibliographical study on tests of qualitative and quantitative prediction (presentation of several models) of the genesis of internal stresses during quench, the author reports the study of the alloy behaviour during cooling and presents the basis of a model of prediction of internal stresses. The next part addresses the determination of the influence of martensitic transformation on the evolution of stresses during quench. The last part reports the taking into account of the effect of stress-phase transformation interaction in the calculation of internal stresses [fr

Salubrious effects of oxytocin on social stress-induced deficits

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Smith, Adam S.; Wang, Zuoxin

2012-01-01

Social relationships are a fundamental aspect of life, affecting social, psychological, physiological, and behavioral functions. While social interactions can attenuate stress and promote health, disruption, confrontations, isolation, or neglect in the social environment can each be major stressors. Social stress can impair the basal function and stress-induced activation of the hypothalamic-pituitary-adrenal (HPA) axis, impairing function of multiple biological systems and posing a risk to mental and physical health. In contrast, social support can ameliorate stress-induced physiological and immunological deficits, reducing the risk of subsequent psychological distress and improving an individual's overall well-being. For better clinical treatment of these physiological and mental pathologies, it is necessary to understand the regulatory mechanisms of stress-induced pathologies as well as determine the underlying biological mechanisms that regulate social buffering of the stress system. A number of ethologically relevant animal models of social stress and species that form strong adult social bonds have been utilized to study the etiology, treatment, and prevention of stress-related disorders. While undoubtedly a number of biological pathways contribute to the social buffering of the stress response, the convergence of evidence denotes the regulatory effects of oxytocin in facilitating social bond-promoting behaviors and their effect on the stress response. Thus, oxytocin may be perceived as a common regulatory element of the social environment, stress response, and stress-induced risks on mental and physical health. PMID:22178036

Impact of water-deficit stress on tritrophic interactions in a wheat-aphid-parasitoid system.

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Syed Suhail Ahmed

Full Text Available Increasing temperature and CO2 concentrations can alter tritrophic interactions in ecosystems, but the impact of increasingly severe drought on such interactions is not well understood. We examined the response of a wheat-aphid-parasitoid system to variation in water-deficit stress levels. Our results showed that arid area clones of the aphid, Sitobion avenae (Fabricius, tended to have longer developmental times compared to semiarid and moist area clones, and the development of S. avenae clones tended to be slower with increasing levels of water-deficit. Body sizes of S. avenae clones from all areas decreased with increasing water-deficit levels, indicating their declining adaptation potential under drought. Compared to arid area clones, moist area clones of S. avenae had a higher frequency of backing under severe water stress only, but a higher frequency of kicking under well-watered conditions only, suggesting a water-deficit level dependent pattern of resistance against the parasitoid, Aphidius gifuensis (Ashmead. The number of S. avenae individuals attacked by the parasitoid in 10 min showed a tendency to decrease with increasing water-deficit levels. Clones of S. avenae tended to have lower parasitism rates under treatments with higher water-deficit levels. The development of the parasitoid tended to be slower under higher levels of water-deficit stress. Thus, the bottom-up effects of water-deficit stressed plants were negative on S. avenae. However, the top-down effects via parasitoids were compromised by water-deficit, which could favor the growth of aphid populations. Overall, the first trophic level under water-deficit stress was shown to have an indirect and negative impact on the third trophic level parasitoid, suggesting that parasitoids could be increasingly vulnerable in future warming scenarios.

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

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

2012-01-01

improvement. Once again, this pattern was not demonstrated in the group exposed to uncontrollable events. These results suggest that stress controllability and subjective response interact to affect high-level cognitive abilities. Specifically, exposure to moderate, controllable stress benefits performance, but exposure to uncontrollable stress or having a more extreme response to stress tends to harm performance. These findings may provide insights on how to leverage the beneficial effects of stress in a range of settings.

Subacute stress and chronic stress interact to decrease intestinal barrier function in rats.

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Lauffer, Adriana; Vanuytsel, Tim; Vanormelingen, Christophe; Vanheel, Hanne; Salim Rasoel, Shadea; Tóth, Joran; Tack, Jan; Fornari, Fernando; Farré, Ricard

2016-01-01

Psychological stress increases intestinal permeability, potentially leading to low-grade inflammation and symptoms in functional gastrointestinal disorders. We assessed the effect of subacute, chronic and combined stress on intestinal barrier function and mast cell density. Male Wistar rats were allocated to four experimental groups (n = 8/group): 1/sham; 2/subacute stress (isolation and limited movement for 24 h); 3/chronic crowding stress for 14 days and 4/combined subacute and chronic stress. Jejunum and colon were collected to measure: transepithelial electrical resistance (TEER; a measure of epithelial barrier function); gene expression of tight junction molecules; mast cell density. Plasma corticosterone concentration was increased in all three stress conditions versus sham, with highest concentrations in the combined stress condition. TEER in the jejunum was decreased in all stress conditions, but was significantly lower in the combined stress condition than in the other groups. TEER in the jejunum correlated negatively with corticosterone concentration. Increased expression of claudin 1, 5 and 8, occludin and zonula occludens 1 mRNAs was detected after subacute stress in the jejunum. In contrast, colonic TEER was decreased only after combined stress, and the expression of tight junction molecules was unaltered. Increased mast cell density was observed in the chronic and combined stress condition in the colon only. In conclusion, our data show that chronic stress sensitizes the gastrointestinal tract to the effects of subacute stress on intestinal barrier function; different underlying cellular and molecular alterations are indicated in the small intestine versus the colon.

How disentangled sense of agency and sense of ownership can interact with different emotional events on stress feelings

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Wei Chen

2017-09-01

Full Text Available Abstract We used the virtual hand illusion paradigm to study how sense of agency and sense of (body ownership can interact with different emotional events on stress feelings. Converging evidence for at least the partial independence of agency and ownership was found. For instance, sense of agency was a better predictor of individual anxiety levels than sense of ownership and males showed stronger effects related to agency—presumably due to gender-specific attribution styles and empathy skills. Moreover, agency and ownership also interacted with emotional events and led to different anxiety levels. Taken together, our findings suggest that the disentangled sense of agency and sense of ownership can interact with different emotional events and influenced stress feelings more in threatening situations than awarding ones.

Screening for interaction effects in gene expression data.

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Peter J Castaldi

Full Text Available Expression quantitative trait (eQTL studies are a powerful tool for identifying genetic variants that affect levels of messenger RNA. Since gene expression is controlled by a complex network of gene-regulating factors, one way to identify these factors is to search for interaction effects between genetic variants and mRNA levels of transcription factors (TFs and their respective target genes. However, identification of interaction effects in gene expression data pose a variety of methodological challenges, and it has become clear that such analyses should be conducted and interpreted with caution. Investigating the validity and interpretability of several interaction tests when screening for eQTL SNPs whose effect on the target gene expression is modified by the expression level of a transcription factor, we characterized two important methodological issues. First, we stress the scale-dependency of interaction effects and highlight that commonly applied transformation of gene expression data can induce or remove interactions, making interpretation of results more challenging. We then demonstrate that, in the setting of moderate to strong interaction effects on the order of what may be reasonably expected for eQTL studies, standard interaction screening can be biased due to heteroscedasticity induced by true interactions. Using simulation and real data analysis, we outline a set of reasonable minimum conditions and sample size requirements for reliable detection of variant-by-environment and variant-by-TF interactions using the heteroscedasticity consistent covariance-based approach.

A fractal model of effective stress of porous media and the analysis of influence factors

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Li, Wei; Zhao, Huan; Li, Siqi; Sun, Wenfeng; Wang, Lei; Li, Bing

2018-03-01

The basic concept of effective stress describes the characteristics of fluid and solid interaction in porous media. In this paper, based on the theory of fractal geometry, a fractal model was built to analyze the relationship between the microstructure and the effective stress of porous media. From the microscopic point of view, the influence of effective stress on pore structure of porous media was demonstrated. Theoretical analysis and experimental results show that: (i) the fractal model of effective stress can be used to describe the relationship between effective stress and the microstructure of porous media; (ii) a linear increase in the effective stress leads to exponential increases in fractal dimension, porosity and pore number of the porous media, and causes a decreasing trend in the average pore radius.

Interactions between biochar and mycorrhizal fungi in a water-stressed agricultural soil.

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Mickan, Bede S; Abbott, Lynette K; Stefanova, Katia; Solaiman, Zakaria M

2016-08-01

Biochar may alleviate plant water stress in association with arbuscular mycorrhizal (AM) fungi but research has not been conclusive. Therefore, a glasshouse experiment was conducted to understand how interactions between AM fungi and plants respond to biochar application under water-stressed conditions. A twin chamber pot system was used to determine whether a woody biochar increased root colonisation by a natural AM fungal population in a pasture soil ('field' chamber) and whether this was associated with increased growth of extraradical AM fungal hyphae detected by plants growing in an adjacent ('bait') chamber containing irradiated soil. The two chambers were separated by a mesh that excluded roots. Subterranean clover was grown with and without water stress and harvested after 35, 49 and 63 days from each chamber. When biochar was applied to the field chamber under water-stressed conditions, shoot mass increased in parallel with mycorrhizal colonisation, extraradical hyphal length and shoot phosphorus concentration. AM fungal colonisation of roots in the bait chamber indicated an increase in extraradical mycorrhizal hyphae in the field chamber. Biochar had little effect on AM fungi or plant growth under well-watered conditions. The biochar-induced increase in mycorrhizal colonisation was associated with increased growth of extraradical AM fungal hyphae in the pasture soil under water-stressed conditions.

Transgenerational effects of stress exposure on offspring phenotypes in apomictic dandelion.

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Koen J F Verhoeven

Full Text Available Heritable epigenetic modulation of gene expression is a candidate mechanism to explain parental environmental effects on offspring phenotypes, but current evidence for environment-induced epigenetic changes that persist in offspring generations is scarce. In apomictic dandelions, exposure to various stresses was previously shown to heritably alter DNA methylation patterns. In this study we explore whether these induced changes are accompanied by heritable effects on offspring phenotypes. We observed effects of parental jasmonic acid treatment on offspring specific leaf area and on offspring interaction with a generalist herbivore; and of parental nutrient stress on offspring root-shoot biomass ratio, tissue P-content and leaf morphology. Some of the effects appeared to enhance offspring ability to cope with the same stresses that their parents experienced. Effects differed between apomictic genotypes and were not always consistently observed between different experiments, especially in the case of parental nutrient stress. While this context-dependency of the effects remains to be further clarified, the total set of results provides evidence for the existence of transgenerational effects in apomictic dandelions. Zebularine treatment affected the within-generation response to nutrient stress, pointing at a role of DNA methylation in phenotypic plasticity to nutrient environments. This study shows that stress exposure in apomictic dandelions can cause transgenerational phenotypic effects, in addition to previously demonstrated transgenerational DNA methylation effects.

Transgenerational effects of stress exposure on offspring phenotypes in apomictic dandelion.

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Verhoeven, Koen J F; van Gurp, Thomas P

2012-01-01

Heritable epigenetic modulation of gene expression is a candidate mechanism to explain parental environmental effects on offspring phenotypes, but current evidence for environment-induced epigenetic changes that persist in offspring generations is scarce. In apomictic dandelions, exposure to various stresses was previously shown to heritably alter DNA methylation patterns. In this study we explore whether these induced changes are accompanied by heritable effects on offspring phenotypes. We observed effects of parental jasmonic acid treatment on offspring specific leaf area and on offspring interaction with a generalist herbivore; and of parental nutrient stress on offspring root-shoot biomass ratio, tissue P-content and leaf morphology. Some of the effects appeared to enhance offspring ability to cope with the same stresses that their parents experienced. Effects differed between apomictic genotypes and were not always consistently observed between different experiments, especially in the case of parental nutrient stress. While this context-dependency of the effects remains to be further clarified, the total set of results provides evidence for the existence of transgenerational effects in apomictic dandelions. Zebularine treatment affected the within-generation response to nutrient stress, pointing at a role of DNA methylation in phenotypic plasticity to nutrient environments. This study shows that stress exposure in apomictic dandelions can cause transgenerational phenotypic effects, in addition to previously demonstrated transgenerational DNA methylation effects.

Sex-Specific Effects of Stress on Oxytocin Neurons Correspond With Responses to Intranasal Oxytocin.

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Steinman, Michael Q; Duque-Wilckens, Natalia; Greenberg, Gian D; Hao, Rebecca; Campi, Katharine L; Laredo, Sarah A; Laman-Maharg, Abigail; Manning, Claire E; Doig, Ian E; Lopez, Eduardo M; Walch, Keenan; Bales, Karen L; Trainor, Brian C

2016-09-01

Oxytocin (OT) is considered to be a stress-buffering hormone, dampening the physiologic effects of stress. However, OT can also be anxiogenic. We examined acute and long-lasting effects of social defeat on OT neurons in male and female California mice. We used immunohistochemistry for OT and c-fos cells to examine OT neuron activity immediately after defeat (n = 6-9) and 2 weeks (n = 6-9) and 10 weeks (n = 4-5) later. We quantified Oxt messenger RNA with quantitative polymerase chain reaction (n = 5-9). Intranasal OT was administered to naïve and stressed mice tested in social interaction and resident-intruder tests (n = 8-14). Acute exposure to a third episode of defeat increased OT/c-fos colocalizations in the paraventricular nucleus of both sexes. In the medioventral bed nucleus of the stria terminalis, defeat increased Oxt messenger RNA, total OT neurons, and OT/c-fos colocalizations in female mice but not male mice. Intranasal OT failed to reverse stress-induced social withdrawal in female mice and reduced social interaction behavior in female mice naïve to defeat. In contrast, intranasal OT increased social interaction in stressed male mice and reduced freezing in the resident-intruder test. Social defeat induces long-lasting increases in OT production and OT/c-fos cells in the medioventral bed nucleus of the stria terminalis of female mice but not male mice. Intranasal OT largely reversed the effects of stress on behavior in male mice, but effects were mixed in female mice. These results suggest that changes in OT-sensitive networks contribute to sex differences in behavioral responses to stress. Copyright © 2015 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Interaction of CD38 Variant and Chronic Interpersonal Stress Prospectively Predicts Social Anxiety and Depression Symptoms Over Six Years

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Tabak, Benjamin A.; Vrshek-Schallhorn, Suzanne; Zinbarg, Richard E.; Prenoveau, Jason M.; Mineka, Susan; Redei, Eva E.; Adam, Emma K.; Craske, Michelle G.

2015-01-01

Variation in the CD38 gene, which regulates secretion of the neuropeptide oxytocin, has been associated with several social phenotypes. Specifically, rs3796863 A allele carriers have demonstrated increased social sensitivity. In 400 older adolescents, we used trait-state-occasion modeling to investigate how rs3796863 genotype, baseline ratings of chronic interpersonal stress, and their gene-environment (GxE) interaction predicted trait social anxiety and depression symptoms over six years. We found significant GxE effects for CD38 A-carrier genotypes and chronic interpersonal stress at baseline predicting greater social anxiety and depression symptoms. A significant GxE effect of smaller magnitude was also found for C/C genotype and chronic interpersonal stress predicting greater depression; however, this effect was small compared to the main effect of chronic interpersonal stress. Thus, in the context of chronic interpersonal stress, heightened social sensitivity associated with the rs3796863 A allele may prospectively predict risk for social anxiety and (to a lesser extent) depression. PMID:26958455

Interactions between stress and physical activity on Alzheimer's disease pathology

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Carla M. Yuede

2018-02-01

Full Text Available Physical activity and stress are both environmental modifiers of Alzheimer's disease (AD risk. Animal studies of physical activity in AD models have largely reported positive results, however benefits are not always observed in either cognitive or pathological outcomes and inconsistencies among findings remain. Studies using forced exercise may increase stress and mitigate some of the benefit of physical activity in AD models, while voluntary exercise regimens may not achieve optimal intensity to provide robust benefit. We evaluated the findings of studies of voluntary and forced exercise regimens in AD mouse models to determine the influence of stress, or the intensity of exercise needed to outweigh the negative effects of stress on AD measures. In addition, we show that chronic physical activity in a mouse model of AD can prevent the effects of acute restraint stress on Aβ levels in the hippocampus. Stress and physical activity have many overlapping and divergent effects on the body and some of the possible mechanisms through which physical activity may protect against stress-induced risk factors for AD are discussed. While the physiological effects of acute stress and acute exercise overlap, chronic effects of physical activity appear to directly oppose the effects of chronic stress on risk factors for AD. Further study is needed to identify optimal parameters for intensity, duration and frequency of physical activity to counterbalance effects of stress on the development and progression of AD. Keywords: Alzheimer's disease, Amyloid, Stress, Exercise, Physical activity

[Effects of shading on two Sphagnum species growth and their interactions].

Science.gov (United States)

Ma, Jin-Ze; Bu, Zhao-Jun; Zheng, Xing-Xing; Li, Shan-Lin; Zeng, Jing; Zhao, Gao-Lin

2012-02-01

Taking Sphagnum palustre and S. fallax as test materials, this paper studied their growth and interactions under shading. In monoculture, shading promoted the height growth of S. palustre markedly, but had no effect on the growth of S. fallax and the biomass and branching of S. palustre. In mixed culture, S. fallax suppressed the increase of biomass and branching of S. palustre, while S. palustre had no effects on S. fallax. With the increase of shading stress, the competition of neighbour on S. fallax intensified. When the stress increased further, neighbor effect on S. fallax tended to be positive. However, the effect of neighbour on S. palustre was always competitive and did not change with the increase of shading stress.

The effects of stress and affiliation on social decision-making: Investigating the tend-and-befriend pattern.

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Steinbeis, Nikolaus; Engert, Veronika; Linz, Roman; Singer, Tania

2015-12-01

The prevalence of psychosocial stress in Western societies is constantly on the rise. Its influence on social decision-making, however, remains poorly understood. Whereas, it is known that stress triggers psychological and physiological defense mechanisms, indications of such patterns in social decisions are ambivalent. We sought to elucidate the underlying mechanisms of stress-induced social decisions. We recruited 145 men, who were individually exposed to either a psychosocial stressor or a control condition, while primed with affiliation by interacting either with members of an in- or an out-group. We found that stressed participants were less trusting and engaged in less costly punishment compared to the non-stressed control group. Interacting with out-group members led to less reciprocity and more spiteful punishment. There was no interaction between stress and the affiliation conditions in any of the used social-decision-making paradigms. Lastly, while stress-reactive cortisol levels had no effect on trust behavior, higher baseline cortisol was correlated with greater trust. Our findings suggest that previous ambiguities in data reported on the influence of stress on social decisions, namely tend-and-befriend behavior may have arisen through critical social confounds in the induction of stress. When controlling for potential social confounds, stress may trigger fight-or-flight behavior as indicated by increased social anxiety. These findings highlight the considerable context-dependence of psychosocial stress and its effects on social behavior. Copyright © 2015 Elsevier Ltd. All rights reserved.

Dynamic stress of impeller blade of shaft extension tubular pump device based on bidirectional fluid-structure interaction

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Kan, Kan; Liu, Huiwen; Yang, Chunxia [Hohai University, Nanjing (China); Zheng, Yuan [National Engineering Research Center of Water Resources Efficient Utilization and Engineering Safety, Nanjing (China); Fu, Shifeng; Zhang, Xin [Power China Huadong Engineering Corporation, Hangzhou (China)

2017-04-15

Current research on the stability of tubular pumps is mainly concerned with the transient hydrodynamic characteristics. However, the structural response under the influence of fluid-structure interaction hasn't been taken fully into consideration. The instability of the structure can cause vibration and cracks, which may threaten the safety of the unit. We used bidirectional fluid-structure interaction to comprehensively analyze the dynamic stress characteristics of the impeller blades of the shaft extension tubular pump device. Furthermore, dynamic stress of impeller blade of shaft extension tubular pump device was solved under different lift conditions of 0° blade angle. Based on Reynolds-average N-S equation and SST k-ω turbulence model, numerical simulation was carried out for three-dimensional unsteady incompressible turbulent flow field of the pump device whole flow passage. Meanwhile, the finite element method was used to calculate dynamic characteristics of the blade structure. The blade dynamic stress distribution was obtained on the basis of fourth strength theory. The research results indicate that the maximum blade dynamic stress appears at the joint between root of inlet side of the blade suction surface and the axis. Considering the influence of gravity, the fluctuation of the blade dynamic stress increases initially and decreases afterwards within a rotation period. In the meantime, the dynamic stress in the middle part of inlet edge presents larger relative fluctuation amplitude. Finally, a prediction method for dynamic stress distribution of tubular pump considering fluid-structure interaction and gravity effect was proposed. This method can be used in the design stage of tubular pump to predict dynamic stress distribution of the structure under different operating conditions, improve the reliability of pump impeller and analyze the impeller fatigue life.

Effects of work-related sleep restriction on acute physiological and psychological stress responses and their interactions: A review among emergency service personnel.

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Wolkow, Alexander; Ferguson, Sally; Aisbett, Brad; Main, Luana

2015-01-01

Emergency work can expose personnel to sleep restriction. Inadequate amounts of sleep can negatively affect physiological and psychological stress responses. This review critiqued the emergency service literature (e.g., firefighting, police/law enforcement, defense forces, ambulance/paramedic personnel) that has investigated the effect of sleep restriction on hormonal, inflammatory and psychological responses. Furthermore, it investigated if a psycho-physiological approach can help contextualize the significance of such responses to assist emergency service agencies monitor the health of their personnel. The available literature suggests that sleep restriction across multiple work days can disrupt cytokine and cortisol levels, deteriorate mood and elicit simultaneous physiological and psychological responses. However, research concerning the interaction between such responses is limited and inconclusive. Therefore, it is unknown if a psycho-physiological relationship exists and as a result, it is currently not feasible for agencies to monitor sleep restriction related stress based on psycho- physiological interactions. Sleep restriction does however, appear to be a major stressor contributing to physiological and psychological responses and thus, warrants further investigation. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Biological effects of laser-induced stress waves

International Nuclear Information System (INIS)

Doukas, A.; Lee, S.; McAuliffe, D.

1995-01-01

Laser-induced stress waves can be generated by one of the following mechanisms: Optical breakdown, ablation or rapid heating of an absorbing medium. These three modes of laser interaction with matter allow the investigation of cellular and tissue responses to stress waves with different characteristics and under different conditions. The most widely studied phenomena are those of the collateral damage seen in photodisruption in the eye and in 193 run ablation of cornea and skin. On the other hand, the therapeutic application of laser-induced stress waves has been limited to the disruption of noncellular material such as renal stones, atheromatous plaque and vitreous strands. The effects of stress waves to cells and tissues can be quite disparate. Stress waves can fracture tissue, damage cells, and increase the permeability of the plasma membrane. The viability of cell cultures exposed to stress waves increases with the peak stress and the number of pulses applied. The rise time of the stress wave also influences the degree of cell injury. In fact, cell viability, as measured by thymidine incorporation, correlates better with the stress gradient than peak stress. Recent studies have also established that stress waves induce a transient increase of the permeability of the plasma membrane in vitro. In addition, if the stress gradient is below the damage threshhold, the cells remain viable. Thus, stress waves can be useful as a means of drug delivery, increasing the intracellular drug concentration and allowing the use of drugs which are impermeable to the cell membrane. The present studies show that it is important to create controllable stress waves. The wavelength tunability and the micropulse structure of the free electron laser is ideal for generating stress waves with independently adjustable parameters, such as rise time, duration and peak stress

Effects of an early intervention on maternal post-traumatic stress symptoms and the quality of mother-infant interaction: the case of preterm birth.

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Borghini, Ayala; Habersaat, Stephanie; Forcada-Guex, Margarita; Nessi, Jennifer; Pierrehumbert, Blaise; Ansermet, François; Müller-Nix, Carole

2014-11-01

Preterm birth may represent a traumatic situation for both parents and a stressful situation for the infant, potentially leading to difficulties in mother-infant relationships. This study aimed to investigate the impact of an early intervention on maternal posttraumatic stress symptoms, and on the quality of mother-infant interactions, in a sample of very preterm infants and their mothers. Half of the very preterm infants involved in the study (n=26) were randomly assigned to a 3-step early intervention program (at 33 and 42 weeks after conception and at 4 months' corrected age). Both groups of preterm infants (with and without intervention) were compared to a group of full-term infants. The impact of the intervention on maternal posttraumatic stress symptoms was assessed 42 weeks after conception and when the infants were 4 and 12 months of age. The impact of the intervention on the quality of mother-infant interactions was assessed when the infants were 4 months old. Results showed a lowering of mothers' posttraumatic stress symptoms between 42 weeks and 12 months in the group of preterm infants who received the intervention. Moreover, an enhancement in maternal sensitivity and infant cooperation during interactions was found at 4 months in the group with intervention. In the case of a preterm birth, an early intervention aimed at enhancing the quality of the mother-infant relationship can help to alleviate maternal post-traumatic stress symptoms and may have a positive impact on the quality of mother-infant interactions. Copyright © 2014 Elsevier Inc. All rights reserved.

Comparing of Normal Stress Distribution in Static and Dynamic Soil-Structure Interaction Analyses

International Nuclear Information System (INIS)

Kholdebarin, Alireza; Massumi, Ali; Davoodi, Mohammad; Tabatabaiefar, Hamid Reza

2008-01-01

It is important to consider the vertical component of earthquake loading and inertia force in soil-structure interaction analyses. In most circumstances, design engineers are primarily concerned about the analysis of behavior of foundations subjected to earthquake-induced forces transmitted from the bedrock. In this research, a single rigid foundation with designated geometrical parameters located on sandy-clay soil has been modeled in FLAC software with Finite Different Method and subjected to three different vertical components of earthquake records. In these cases, it is important to evaluate effect of footing on underlying soil and to consider normal stress in soil with and without footing. The distribution of normal stress under the footing in static and dynamic states has been studied and compared. This Comparison indicated that, increasing in normal stress under the footing caused by vertical component of ground excitations, has decreased dynamic vertical settlement in comparison with static state

Effects of Stress Related to the Gulf Oil Spill on Child and Adolescent Mental Health.

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Osofsky, Joy D; Osofsky, Howard J; Weems, Carl F; Hansel, Tonya C; King, Lucy S

2016-01-01

To examine the interactive effects of stress related to the Gulf oil spill on mental health of children and adolescents on the Gulf Coast who were also affected by previous hurricanes. A prospective design, with n = 1,577 youth (aged 3-18 years), evaluated pre-oil spill and again post-oil spill for posttraumatic stress disorder (PTSD) symptoms, previous hurricane exposure, and amount of oil spill stress. Stressors related to the spill were common and were associated with PTSD symptoms. Moreover, there was an interactive effect such that those with high preexisting PTSD symptoms, high previous hurricane exposure, and high oil spill stress had the most elevated post-oil spill PTSD symptoms. This study provides initial evidence linking stress related to the Gulf oil spill to youth mental health symptoms. The effects of the oil spill on youth mental health were most evident among those with cumulative risk. © The Author 2014. Published by Oxford University Press on behalf of the Society of Pediatric Psychology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Stress intensity factors of corner cracks in two nozzle-cylinder interactions

International Nuclear Information System (INIS)

Kobayashi, A.S.; Polvanich, N.; Emery, A.F.; Love, W.J.

1977-01-01

In a recent paper, the authors presented the stress-intensity-magnification factors of a quarter-elliptical surface crack in a quarter-infinite solid and a circular crack approaching a reentry corner in a three-quarter infinite solid. These stress-intensity-magnification factors were used together with a curvature-correction factor to estimate the stress-intensity factor of a corner crack at a nozzle-cylinder interaction. Through appropriate superposition of the above stress-intensity-magnification factors, stress-intensity factors for hypothetical corner cracks at a nozzle-cylinder intersection subjected to internal pressure and transient thermal-stress loadings can be obtained. A description of a computer code based on this procedure as well as its applications in analyzing two corner-crack probems at a nozzle-cylinder intersection are discussed in this paper. (Auth.)

Nutrients versus emerging contaminants–Or a dynamic match between subsidy and stress effects on stream biofilms

International Nuclear Information System (INIS)

Aristi, I.; Casellas, M.; Elosegi, A.; Insa, S.; Petrovic, M.; Sabater, S.; Acuña, V.

2016-01-01

Freshwater ecosystems are threatened by multiple anthropogenic stressors, which might be differentiated into two types: those that reduce biological activity at all concentrations (toxic contaminants), and those that subsidize biological activity at low concentrations and reduce it at high concentrations (assimilable contaminants). When occurring in mixtures, these contaminants can have either antagonistic, neutral or synergistic effects; but little is known on their joint effects. We assessed the interaction effects of a mixture of assimilable and toxic contaminants on stream biofilms in a manipulative experiment using artificial streams, and following a factorial design with three nutrient levels (low, medium or high) and either presence or absence of a mixture of emerging contaminants (ciprofloxacin, erythromycin, diclofenac, methylparaben, and sulfamethoxazole). We measured biofilm biomass, basal fluorescence, gross primary production and community respiration. Our initial hypotheses were that biofilm biomass and activity would: increase with medium nutrient concentrations (subsidy effect), but decrease with high nutrient concentrations (stress effect) (i); decrease with emerging contaminants, with the minimum decrease at medium nutrient concentrations (antagonistic interaction between nutrients subsidy and stress by emerging contaminants) and the maximum decrease at high nutrient concentrations (synergistic interaction between nutrients and emerging contaminants stress) (ii). All the measured variables responded linearly to the available nutrients, with no toxic effect at high nutrient concentrations. Emerging contaminants only caused weak toxic effects in some of the measured variables, and only after 3–4 weeks of exposure. Therefore, only antagonistic interactions were observed between nutrients and emerging contaminants, as medium and high nutrient concentrations partly compensated the harmful effects of emerging contaminants during the first weeks of the

Blunted cortisol response to acute pre-learning stress prevents misinformation effect in a forced confabulation paradigm.

Science.gov (United States)

Zoladz, Phillip R; Cadle, Chelsea E; Dailey, Alison M; Fiely, Miranda K; Peters, David M; Nagle, Hannah E; Mosley, Brianne E; Scharf, Amanda R; Brown, Callie M; Duffy, Tessa J; Earley, McKenna B; Rorabaugh, Boyd R; Payment, Kristie E

2017-07-01

Research examining the effects of stress on false memory formation has been equivocal, partly because of the complex nature of stress-memory interactions. A major factor influencing stress effects on learning is the timing of stress relative to encoding. Previous work has shown that brief stressors administered immediately before learning enhance long-term memory. Thus, we predicted that brief stress immediately before learning would decrease participants' susceptibility to subsequent misinformation and reduce false memory formation. Eighty-four male and female participants submerged their hand in ice cold (stress) or warm (no stress) water for 3min. Immediately afterwards, they viewed an 8-min excerpt from the Disney movie Looking for Miracles. The next day, participants were interviewed and asked several questions about the video, some of which forced them to confabulate responses. Three days and three weeks later, respectively, participants completed a recognition test in the lab and a free recall test via email. Our results revealed a robust misinformation effect, overall, as participants falsely recognized a significant amount of information that they had confabulated during the interview as having occurred in the original video. Stress, overall, did not significantly influence this misinformation effect. However, the misinformation effect was completely absent in stressed participants who exhibited a blunted cortisol response to the stress, for both recognition and recall tests. The complete absence of a misinformation effect in non-responders may lend insight into the interactive roles of autonomic arousal and corticosteroid levels in false memory development. Copyright © 2017 Elsevier Inc. All rights reserved.

Combined effects of water, nutrient, and UV-B stress on female fitness in Brassica (Brassicaceae)

International Nuclear Information System (INIS)

Conner, J.K.; Zangori, L.A.

1998-01-01

Our knowledge of the effects of increased levels of ultraviolet-B radiation (UV-B) on plant fitness is limited mainly to yield studies in a few crop species. Previous greenhouse and garden studies of Brassica have found greater detrimental effects of UV-B on fitness in gardens than in the greenhouse, suggesting the possibility that additional stresses in the field decrease the ability of Brassica to cope with UV-B. Possible interactions between UV-B and water/nutrient stress in determining plant fitness have rarely, if ever, been studied experimentally. Here we report measurements of female fitness in two species of Brassica in an experiment in which both UV-B and levels of water and nutrients were varied in a 2 X 2 factorial design. Water and nutrient stress reduced female fitness in both species, while UV-B caused fitness reductions in only one of the species. There was evidence for interactions between UV-B and water/nutrient stress for only a few of the traits measured; most traits, including those closely related to fitness, showed no evidence of an interaction

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

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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.

Phenotypic effects of repeated psychosocial stress during adolescence in mice mutant for the schizophrenia risk gene neuregulin-1: a putative model of gene × environment interaction.

Science.gov (United States)

Desbonnet, Lieve; O'Tuathaigh, Colm; Clarke, Gerard; O'Leary, Claire; Petit, Emilie; Clarke, Niamh; Tighe, Orna; Lai, Donna; Harvey, Richard; Cryan, John F; Dinan, Timothy G; Waddington, John L

2012-05-01

There is a paucity of animal models by which the contributions of environmental and genetic factors to the pathobiology of psychosis can be investigated. This study examined the individual and combined effects of chronic social stress during adolescence and deletion of the schizophrenia risk gene neuregulin-1 (NRG1) on adult mouse phenotype. Mice were exposed to repeated social defeat stress during adolescence and assessed for exploratory behaviour, working memory, sucrose preference, social behaviour and prepulse inhibition in adulthood. Thereafter, in vitro cytokine responses to mitogen stimulation and corticosterone inhibition were assayed in spleen cells, with measurement of cytokine and brain-derived neurotrophic factor (BDNF) mRNA in frontal cortex, hippocampus and striatum. NRG1 mutants exhibited hyperactivity, decreased anxiety, impaired sensorimotor gating and reduced preference for social novelty. The effects of stress on exploratory/anxiety-related parameters, spatial working memory, sucrose preference and basal cytokine levels were modified by NRG1 deletion. Stress also exerted varied effect on spleen cytokine response to concanavalin A and brain cytokine and BDNF mRNA expression in NRG1 mutants. The experience of psychosocial stress during adolescence may trigger further pathobiological features that contribute to the development of schizophrenia, particularly in those with underlying NRG1 gene abnormalities. This model elaborates the importance of gene × environment interactions in the etiology of schizophrenia. Copyright © 2012 Elsevier Inc. All rights reserved.

Effects of larvicidal and larval nutritional stresses on Anopheles gambiae development, survival and competence for Plasmodium falciparum.

Science.gov (United States)

Vantaux, Amélie; Ouattarra, Issiaka; Lefèvre, Thierry; Dabiré, Kounbobr Roch

2016-04-23

Many studies have shown that the environment in which larvae develop can influence adult characteristics with consequences for the transmission of pathogens. We investigated how two environmental stresses (larviciding and nutritional stress) interact to affect Anopheles gambiae (previously An. gambiae S molecular form) life history traits and its susceptibility for field isolates of its natural malaria agent Plasmodium falciparum. Larvae were reared in the presence or not of a sub-lethal concentration of larvicide and under a high and low food regimen. Development time, individual size, adult survival and competence for P. falciparum were assessed. Individuals under low food regimen took more time to develop, had a lower development success and were smaller while there was no main effect of larvicide exposure on these traits. However, larvicide exposure impacted individual size in interaction with nutritional stress. Female survival was affected by the interaction between gametocytemia, parasite exposure and larval diet, as well as the interaction between gametocytemia, parasite exposure and larvicidal stress, and the interaction between gametocytemia, larvicidal exposure and larval diet. Among the 951 females dissected 7 days post-infection, 559 (58.78%) harboured parasites. Parasite prevalence was significantly affected by the interaction between larvicidal stress and larval diet. Indeed, females under low food regimen had a higher prevalence than females under high food regimen and this difference was greater under larvicidal stress. The two stresses did not impact parasite intensity. We found that larval nutritional and larvicidal stresses affect mosquito life history traits in complex ways, which could greatly affect P. falciparum transmission. Further studies combining field-based trials on larvicide use and mosquito experimental infections would give a more accurate understanding of the effects of this vector control tool on malaria transmission.

The effect of consumer pressure and abiotic stress on positive plant interactions are mediated by extreme climatic events.

Science.gov (United States)

Filazzola, Alessandro; Liczner, Amanda Rae; Westphal, Michael; Lortie, Christopher J

2018-01-01

Environmental extremes resulting from a changing climate can have profound implications for plant interactions in desert communities. Positive interactions can buffer plant communities from abiotic stress and consumer pressure caused by climatic extremes, but limited research has explored this empirically. We tested the hypothesis that the mechanism of shrub facilitation on an annual plant community can change with precipitation extremes in deserts. During years of extreme drought and above-average rainfall in a desert, we measured plant interactions and biomass while manipulating a soil moisture gradient and reducing consumer pressure. Shrubs facilitated the annual plant community at all levels of soil moisture through reductions in microclimatic stress in both years and herbivore protection in the wet year only. Shrub facilitation and the high rainfall year contributed to the dominance of a competitive annual species in the plant community. Precipitation patterns in deserts determine the magnitude and type of facilitation mechanisms. Moreover, shrub facilitation mediates the interspecific competition within the associated annual community between years with different rainfall amounts. Examining multiple drivers during extreme climate events is a challenging area of research, but it is a necessary consideration given forecasts predicting that these events will increase in frequency and magnitude. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

[Mediating effect of mental elasticity on occupational stress and depression in female nurses].

Science.gov (United States)

Wang, Y W; Liu, G Z; Zhou, X T; Sheng, P J; Cui, F F; Shi, T

2017-06-20

Objective: To investigate the interaction between mental elasticityand occupational stress and depressionin female nurses and the mediating effect of mental elasticity, as well as the functioning way of mental elasticity in occupational stress-depression. Methods: From August to October, 2015, cluster sampling was used to select 122 female nurses in a county-level medical institution as study subjects. The Connor-Davidson Resilience Scale (CD-RISC) , Occupational Stress Inventory-Revised Edition (OSI-R) , and Self-Rating Depression Scale (SDS) were used to collect the data on mental elasticity, occupational stress, and depression and analyze their correlation and mediating effect. Results: The 122 female nurses had a mean mental elasticity score of 62.4±15.1, which was significantly lower than the Chinese norm (65.4±13.9) ( P occupational stress and depression ( r =-0.559 and -0.559, both P Occupational stress and the two subscales mental stress reaction and physical stress reaction were positively correlated with depression ( r =0.774, 0.734, and 0.725, all P occupational stress had a positive predictive effect on depression ( β =0.744, P occupational stress on depression and a significant mediating effect of mental elasticity ( a =-0.527, b =-0.227, c =0.744, c '=0.627; all P occupational stress and depression and can alleviate the adverse effect of occupational stress and reduce the development of depression.

Cadmium and lead interactive effects on oxidative stress and antioxidative responses in rice seedlings.

Science.gov (United States)

Srivastava, Rajneesh Kumar; Pandey, Poonam; Rajpoot, Ritika; Rani, Anjana; Dubey, R S

2014-09-01

Interactive effects of two heavy metal pollutants Cd and Pb in the growth medium were examined on their uptake, production of reactive oxygen species (ROS), induction of oxidative stress and antioxidative defence responses in Indica rice (Oryza sativa L.) seedlings. When rice seedlings in sand culture were exposed to 150 μM Cd (NO3)2 or 600 μM Pb (CH3COO)2 individually or in combination for 8-16 days, a significant reduction in root/shoot length, fresh weight, relative water content, photosynthetic pigments and increased production of ROS (O2˙- and H2O2) was observed. Both Cd and Pb were readily taken up by rice roots and localisation of absorbed metals was greater in roots than in shoots. When present together in the growth medium, uptake of both the metals Cd and Pb declined by 25-40%. Scanning electron microscope (SEM) imaging of leaf stomata revealed that Pb caused more distortion in the shape of guard cells than Cd. Dithizone staining of roots showed localisation of absorbed Cd on root hairs and epidermal cells. Both Cd and Pb caused increased lipid peroxidation, protein carbonylation, decline in protein thiol and increase in non-protein thiol. The level of reduced forms of non-enzymic antioxidants glutathione (GSH) and ascorbate (AsA) and their redox ratios (GSH/AsA) declined, whereas the activities of antioxidative enzymes superoxide dismutase (SOD) and guaiacol peroxidase (GPX) increased in metal treated seedlings compared to controls. In-gel activity staining also revealed increased intensities of SOD and GPX isoforms with metal treatments. Catalase (CAT) activity increased during early days (8 days) of metal exposure and declined by 16 days. Results suggest that oxidative stress is an important component in expression of Cd and Pb toxicities in rice, though uptake of both metals gets reduced considerably when present together in the medium.

Estrogen and voluntary exercise interact to attenuate stress-induced corticosterone release but not anxiety-like behaviors in female rats.

Science.gov (United States)

Jones, Alexis B; Gupton, Rebecca; Curtis, Kathleen S

2016-09-15

The beneficial effects of physical exercise to reduce anxiety and depression and to alleviate stress are increasingly supported in research studies. The role of ovarian hormones in interactions between exercise and anxiety/stress has important implications for women's health, given that women are at increased risk of developing anxiety-related disorders, particularly during and after the menopausal transition. In these experiments, we tested the hypothesis that estrogen enhances the positive impact of exercise on stress responses by investigating the combined effects of exercise and estrogen on anxiety-like behaviors and stress hormone levels in female rats after an acute stressor. Ovariectomized female rats with or without estrogen were given access to running wheels for one or three days of voluntary running immediately after or two days prior to being subjected to restraint stress. We found that voluntary running was not effective at reducing anxiety-like behaviors, whether or not rats were subjected to restraint stress. In contrast, stress-induced elevations of stress hormone levels were attenuated by exercise experience in estrogen-treated rats, but were increased in rats without estrogen. These results suggest that voluntary exercise may be more effective at reducing stress hormone levels if estrogen is present. Additionally, exercise experience, or the distance run, may be important in reducing stress. Copyright © 2016 Elsevier B.V. All rights reserved.

Interaction Effect of Pressurized Lamination Pipe by using 2D Finite Element Analysis

International Nuclear Information System (INIS)

Razak, N; Sulaiman, A; Alang, N

2012-01-01

The availability of the multiple sites is often observed in pipeline and their interaction and coalescence may significantly affect their life. In this paper the finite element method has been used to study the effect of pressure defect on the stress field and their interaction in the interlaminar region. The effect of the crack size and the pressure defect will be investigated. The results are presented as the evolution of the stress field in the interlaminar region as a function of the pressure defect. It is observed that for two cracks with equal length, the pressure inside the lamination give greater value than those for unequal length

Effects of prenatal stress on fetal and child development: a critical literature review.

Science.gov (United States)

Graignic-Philippe, R; Dayan, J; Chokron, S; Jacquet, A-Y; Tordjman, S

2014-06-01

Many studies have examined effects of prenatal stress on pregnancy and fetal development, especially on prematurity and birthweight, and more recently long-term effects on child behavioral and emotional development. These studies are reviewed and their limitations are discussed with regard to definitions (including the concepts of stress and anxiety), stress measurements, samples, and control for confounds such as depression. It appears necessary to assess individual stress reactivity prospectively and separately at each trimester of pregnancy, to discriminate chronic from acute stress, and to take into consideration moderator variables such as past life events, sociocultural factors, predictability, social support and coping strategies. Furthermore, it might be useful to examine simultaneously, during but also after pregnancy, stress, anxiety and depression in order to understand better their relationships and to evaluate their specific effects on pregnancy and child development. Finally, further research could benefit from an integrated psychological and biological approach studying together subjective perceived stress and objective physiological stress responses in pregnant women, and their effects on fetal and child development as well as on mother-infant interactions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of drought and salt stresses on growth characteristics of euhalophyte Suaeda salsa in coastal wetlands

Science.gov (United States)

Jia, Jia; Huang, Chen; Bai, Junhong; Zhang, Guangliang; Zhao, Qingqing; Wen, Xiaojun

2018-02-01

The pot experiment was carried out in the Yellow River Delta to investigate the effects of drought and salt stresses on growth characteristics of Suaeda salsa, and to reveal the role of nitrogen (N) application in alleviation effects of drought and salt stresses on Suaeda salsa in coastal wetlands. In this study, plants were exposed to two water contents treatments (i.e., 14% and 26% water content), four salinity treatments (i.e., 2 g/kg, 4 g/kg, 6 g/kg, and 8 g/kg NaCl) and two N application treatments (i.e., 0 and 200 N mg/kg) in field conditions. Growth characteristics of Suaeda salsa were assessed as fresh weight, dry weight, height, total nitrogen (TN) and total carbon (TC). Our results showed that fresh weight, dry weight and height of Suaeda salsa promoted at lower salinity treatments but reduced at higher salinity treatments, while TN and TC contents kept stable with increasing salinity levels. Drought stress diminished the fresh weight, dry weight and height of Suaeda salsa, whereas enhanced TN contents. Under the interactive stresses of drought and salt, fresh weight and dry weight showed slight increases at lower salinity treatments, whereas decreases at higher salinity treatments. N application promoted the fresh weight, dry weight and TN contents other than the height and TC contents of Suaeda salsa. The interaction between N application and salt stress exhibited a significant influence on the fresh weight and dry weight of Suaeda salsa, whereas no significant interaction between N application and drought stress was observed. These findings of this study suggested that higher salinity, drought and the interaction of drought and higher salinity would retard the growth of Suaeda salsa, whereas N application could only mitigate the deleterious effects of salt stress on Suaeda salsa.

Effect of stress evolution on microstructural behavior in U-Mo/Al dispersion fuel

Energy Technology Data Exchange (ETDEWEB)

Jeong, G.Y. [Department of Nuclear Engineering, Ulsan National Institute of Science and Technology, 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 689-798 (Korea, Republic of); Kim, Yeon Soo; Jamison, L.M. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Robinson, A.B. [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-6188 (United States); Lee, K.H. [Korea Atomic Energy Research Institute, 989-111 Daedeokdaero, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Sohn, Dong-Seong, E-mail: dssohn@unist.ac.kr [Department of Nuclear Engineering, Ulsan National Institute of Science and Technology, 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 689-798 (Korea, Republic of)

2017-04-15

U-Mo/Al dispersion fuel irradiated to high burnup at high power (high fission rate) exhibited microstructural changes including deformation of the fuel particles, pore growth, and rupture of the Al matrix. The driving force for these microstructural changes was meat swelling resulting from a combination of fuel particle swelling and interaction layer (IL) growth. In some cases, pore growth in the interaction layers also contributed to meat swelling. The main objective of this work was to determine the stress distribution within the fuel meat that caused these phenomena. A mechanical equilibrium between the stress generated by fuel meat swelling and the stress relieved by fission-induced creep in the meat constituents (U-Mo particles, Al matrix, and IL) was considered. Test plates with well-recorded fabrication data and irradiation conditions were used, and their post-irradiation examination (PIE) data was obtained. ABAQUS finite element analysis (FEA) was utilized to simulate the microstructural evolution of the plates. The simulation results allowed for the determination of effective stress and hydrostatic stress exerted on the meat constituents. The effects of fabrication and irradiation parameters on the stress distribution that drives microstructural evolutions, such as pore growth in the IL and Al matrix rupture, were investigated. - Highlights: •Post-irradiation data for irradiated miniplates were analyzed by using their optical microscopy images. •ABAQUS finite element analysis (FEA) package was utilized to simulate the microstructural evolution of the selected plates. •Stresses were assessed to analyze their effects on microstructural changes during irradiation.

Neurobiological Interactions Between Stress and the Endocannabinoid System.

Science.gov (United States)

Morena, Maria; Patel, Sachin; Bains, Jaideep S; Hill, Matthew N

2016-01-01

Stress affects a constellation of physiological systems in the body and evokes a rapid shift in many neurobehavioral processes. A growing body of work indicates that the endocannabinoid (eCB) system is an integral regulator of the stress response. In the current review, we discuss the evidence to date that demonstrates stress-induced regulation of eCB signaling and the consequential role changes in eCB signaling have with respect to many of the effects of stress. Across a wide array of stress paradigms, studies have generally shown that stress evokes bidirectional changes in the two eCB molecules, anandamide (AEA) and 2-arachidonoyl glycerol (2-AG), with stress exposure reducing AEA levels and increasing 2-AG levels. Additionally, in almost every brain region examined, exposure to chronic stress reliably causes a downregulation or loss of cannabinoid type 1 (CB1) receptors. With respect to the functional role of changes in eCB signaling during stress, studies have demonstrated that the decline in AEA appears to contribute to the manifestation of the stress response, including activation of the hypothalamic-pituitary-adrenal (HPA) axis and increases in anxiety behavior, while the increased 2-AG signaling contributes to termination and adaptation of the HPA axis, as well as potentially contributing to changes in pain perception, memory and synaptic plasticity. More so, translational studies have shown that eCB signaling in humans regulates many of the same domains and appears to be a critical component of stress regulation, and impairments in this system may be involved in the vulnerability to stress-related psychiatric conditions, such as depression and posttraumatic stress disorder. Collectively, these data create a compelling argument that eCB signaling is an important regulatory system in the brain that largely functions to buffer against many of the effects of stress and that dynamic changes in this system contribute to different aspects of the stress response.

Nutrients versus emerging contaminants-Or a dynamic match between subsidy and stress effects on stream biofilms.

Science.gov (United States)

Aristi, I; Casellas, M; Elosegi, A; Insa, S; Petrovic, M; Sabater, S; Acuña, V

2016-05-01

Freshwater ecosystems are threatened by multiple anthropogenic stressors, which might be differentiated into two types: those that reduce biological activity at all concentrations (toxic contaminants), and those that subsidize biological activity at low concentrations and reduce it at high concentrations (assimilable contaminants). When occurring in mixtures, these contaminants can have either antagonistic, neutral or synergistic effects; but little is known on their joint effects. We assessed the interaction effects of a mixture of assimilable and toxic contaminants on stream biofilms in a manipulative experiment using artificial streams, and following a factorial design with three nutrient levels (low, medium or high) and either presence or absence of a mixture of emerging contaminants (ciprofloxacin, erythromycin, diclofenac, methylparaben, and sulfamethoxazole). We measured biofilm biomass, basal fluorescence, gross primary production and community respiration. Our initial hypotheses were that biofilm biomass and activity would: increase with medium nutrient concentrations (subsidy effect), but decrease with high nutrient concentrations (stress effect) (i); decrease with emerging contaminants, with the minimum decrease at medium nutrient concentrations (antagonistic interaction between nutrients subsidy and stress by emerging contaminants) and the maximum decrease at high nutrient concentrations (synergistic interaction between nutrients and emerging contaminants stress) (ii). All the measured variables responded linearly to the available nutrients, with no toxic effect at high nutrient concentrations. Emerging contaminants only caused weak toxic effects in some of the measured variables, and only after 3-4 weeks of exposure. Therefore, only antagonistic interactions were observed between nutrients and emerging contaminants, as medium and high nutrient concentrations partly compensated the harmful effects of emerging contaminants during the first weeks of the

Cell-substrate interaction with cell-membrane-stress dependent adhesion.

Science.gov (United States)

Jiang, H; Yang, B

2012-01-10

Cell-substrate interaction is examined in a two-dimensional mechanics model. The cell and substrate are treated as a shell and an elastic solid, respectively. Their interaction through adhesion is treated using nonlinear springs. Compared to previous cell mechanics models, the present model introduces a cohesive force law that is dependent not only on cell-substrate distance but also on internal cell-membrane stress. It is postulated that a living cell would establish focal adhesion sites with density dependent on the cell-membrane stress. The formulated mechanics problem is numerically solved using coupled finite elements and boundary elements for the cell and the substrate, respectively. The nodes in the adhesion zone from either side are linked by the cohesive springs. The specific cases of a cell adhering to a homogeneous substrate and a heterogeneous bimaterial substrate are examined. The analyses show that the substrate stiffness affects the adhesion behavior significantly and regulates the direction of cell adhesion, in good agreement with the experimental results in the literature. By introducing a reactive parameter (i.e., cell-membrane stress) linking biological responses of a living cell to a mechanical environment, the present model offers a unified mechanistic vehicle for characterization and prediction of living cell responses to various kinds of mechanical stimuli including local extracellular matrix and neighboring cells. Copyright © 2011 Elsevier Ltd. All rights reserved.

Rupture Dynamics along Thrust Dipping Fault: Inertia Effects due to Free Surface Wave Interactions

Science.gov (United States)

Vilotte, J. P.; Scala, A.; Festa, G.

2017-12-01

We numerically investigate the dynamic interaction between free surface and up-dip, in-plane rupture propagation along thrust faults, under linear slip-weakening friction. With reference to shallow along-dip rupture propagation during large subduction earthquakes, we consider here low dip-angle fault configurations with fixed strength excess and depth-increasing initial stress. In this configuration, the rupture undergoes a break of symmetry with slip-induced normal stress perturbations triggered by the interaction with reflected waves from the free surface. We found that both body-waves - behind the crack front - and surface waves - at the crack front - can trigger inertial effects. When waves interact with the rupture before this latter reaches its asymptotic speed, the rupture can accelerate toward the asymptotic speed faster than in the unbounded symmetric case, as a result of these inertial effects. Moreover, wave interaction at the crack front also affects the slip rate generating large ground motion on the hanging wall. Imposing the same initial normal stress, frictional strength and stress drop while varying the static friction coefficient we found that the break of symmetry makes the rupture dynamics dependent on the absolute value of friction. The higher the friction the stronger the inertial effect both in terms of rupture acceleration and slip amount. When the contact condition allows the fault interface to open close to the free surface, the length of the opening zone is shown to depend on the propagation length, the initial normal stress and the static friction coefficient. These new results are shown to agree with analytical results of rupture propagation in bounded media, and open new perspectives for understanding the shallow rupture of large subduction earthquakes and tsunami sources.

SOCIAL INTERACTIONS, STRESSFUL EVENTS AND NEGATIVE AFFECT AT WORK - A MICROANALYTIC APPROACH

NARCIS (Netherlands)

PEETERS, MCW; BUUNK, BP; SCHAUFELI, WB

1995-01-01

In the present study a daily event-recording method, the DIRO (Daily Interaction Record in Organizations), was employed for assessing social interactions, stressful events and negative affect at work. Forty-one secretaries filled out the records during the course of a week. This made it possible to

Interactions between financial stress and economic activity for the U.S.: A time- and frequency-varying analysis using wavelets

Science.gov (United States)

Ferrer, Román; Jammazi, Rania; Bolós, Vicente J.; Benítez, Rafael

2018-02-01

This paper examines the interactions between the main U.S. financial stress indices and several measures of economic activity in the time-frequency domain using a number of continuous cross-wavelet tools, including the usual wavelet squared coherence and phase difference as well as two new summary wavelet-based measures. The empirical results show that the relationship between financial stress and the U.S. real economy varies considerably over time and depending on the time horizon considered. A significant adverse effect of financial stress on U.S. economic activity is observed since the onset of the subprime mortgage crisis in the summer of 2007, indicating that the impact of financial market stress on the real economy is particularly severe during periods of major financial turmoil. Furthermore, the significant linkage between financial stress and the economic environment is mostly concentrated at time horizons from one to four years, demonstrating that the effect of financial stress on economic activity is especially visible in the long-run.

Perinatal fluoxetine effects on social play, the HPA system, and hippocampal plasticity in pre-adolescent male and female rats: Interactions with pre-gestational maternal stress.

Science.gov (United States)

Gemmel, Mary; Hazlett, Mariah; Bögi, Eszter; De Lacalle, Sonsoles; Hill, Lesley A; Kokras, Nikolaos; Hammond, Geoffrey L; Dalla, Christina; Charlier, Thierry D; Pawluski, Jodi L

2017-10-01

Selective serotonin reuptake inhibitor medications (SSRIs) are the first lines of treatment for maternal affective disorders, and are prescribed to up to 10% of pregnant women. Concern has been raised about how perinatal exposure to these medications affect offspring neurobehavioral outcomes, particularly those related to social interactions, as recent research has reported conflicting results related to autism spectrum disorder (ASD) risk in children prenatally exposed to SSRIs. Therefore, the aim of this work was to investigate the effects of perinatal exposure to the SSRI fluoxetine on social play behaviors and the hypothalamic pituitary adrenal system, using a model of pre-gestational maternal stress. We also investigated synaptic proteins in the CA2, CA3, and dentate gyrus of the hippocampus, as well as number of immature neurons in the granule cell layer, as both measures of plasticity in the hippocampus have been linked to social behaviors. In pre-adolescent male and female Sprague-Dawley rat offspring, main findings show that perinatal fluoxetine prevents the negative effect of maternal stress on sibling play behavior. However, perinatal fluoxetine increased social aggressive play with a novel conspecific in both sexes and decreased time grooming a novel conspecific in males only. Perinatal fluoxetine also increased serum corticosteroid binding globulin levels, 5-HT levels in the hippocampus, and pre-synaptic density assessed via synaptophysin in the dentate gyrus. Social interaction was significantly correlated with changes in plasticity in the CA2 region of the hippocampus. Pre-gestational maternal stress exposure resulted in significantly decreased rates of hippocampal neurogenesis and synaptophysin density in the dentate gyrus of pre-adolescent males, but not females. Together, these results further characterize the role of perinatal SSRIs, maternal stress prior to conception, and sex/gender on developing social behaviors and related plasticity in the

A new coal-permeability model: Internal swelling stress and fracture-matrix interaction

Energy Technology Data Exchange (ETDEWEB)

Liu, H.H.; Rutqvist, J.

2009-10-01

We have developed a new coal-permeability model for uniaxial strain and constant confining stress conditions. The model is unique in that it explicitly considers fracture-matrix interaction during coal deformation processes and is based on a newly proposed internal-swelling stress concept. This concept is used to account for the impact of matrix swelling (or shrinkage) on fracture-aperture changes resulting from partial separation of matrix blocks by fractures that do not completely cut through the whole matrix. The proposed permeability model is evaluated with data from three Valencia Canyon coalbed wells in the San Juan Basin, where increased permeability has been observed during CH{sub 4} gas production, as well as with published data from laboratory tests. Model results are generally in good agreement with observed permeability changes. The importance of fracture-matrix interaction in determining coal permeability, demonstrated in this work using relatively simple stress conditions, underscores the need for a dual-continuum (fracture and matrix) mechanical approach to rigorously capture coal-deformation processes under complex stress conditions, as well as the coupled flow and transport processes in coal seams.

Sex Differences in Social Interaction Behavior Following Social Defeat Stress in the Monogamous California Mouse (Peromyscus californicus)

Science.gov (United States)

Trainor, Brian C.; Pride, Michael C.; Villalon Landeros, Rosalina; Knoblauch, Nicholas W.; Takahashi, Elizabeth Y.; Silva, Andrea L.; Crean, Katie K.

2011-01-01

Stressful life experiences are known to be a precipitating factor for many mental disorders. The social defeat model induces behavioral responses in rodents (e.g. reduced social interaction) that are similar to behavioral patterns associated with mood disorders. The model has contributed to the discovery of novel mechanisms regulating behavioral responses to stress, but its utility has been largely limited to males. This is disadvantageous because most mood disorders have a higher incidence in women versus men. Male and female California mice (Peromyscus californicus) aggressively defend territories, which allowed us to observe the effects of social defeat in both sexes. In two experiments, mice were exposed to three social defeat or control episodes. Mice were then behaviorally phenotyped, and indirect markers of brain activity and corticosterone responses to a novel social stimulus were assessed. Sex differences in behavioral responses to social stress were long lasting (4 wks). Social defeat reduced social interaction responses in females but not males. In females, social defeat induced an increase in the number of phosphorylated CREB positive cells in the nucleus accumbens shell after exposure to a novel social stimulus. This effect of defeat was not observed in males. The effects of defeat in females were limited to social contexts, as there were no differences in exploratory behavior in the open field or light-dark box test. These data suggest that California mice could be a useful model for studying sex differences in behavioral responses to stress, particularly in neurobiological mechanisms that are involved with the regulation of social behavior. PMID:21364768

Sex differences in social interaction behavior following social defeat stress in the monogamous California mouse (Peromyscus californicus.

Directory of Open Access Journals (Sweden)

Brian C Trainor

2011-02-01

Full Text Available Stressful life experiences are known to be a precipitating factor for many mental disorders. The social defeat model induces behavioral responses in rodents (e.g. reduced social interaction that are similar to behavioral patterns associated with mood disorders. The model has contributed to the discovery of novel mechanisms regulating behavioral responses to stress, but its utility has been largely limited to males. This is disadvantageous because most mood disorders have a higher incidence in women versus men. Male and female California mice (Peromyscus californicus aggressively defend territories, which allowed us to observe the effects of social defeat in both sexes. In two experiments, mice were exposed to three social defeat or control episodes. Mice were then behaviorally phenotyped, and indirect markers of brain activity and corticosterone responses to a novel social stimulus were assessed. Sex differences in behavioral responses to social stress were long lasting (4 wks. Social defeat reduced social interaction responses in females but not males. In females, social defeat induced an increase in the number of phosphorylated CREB positive cells in the nucleus accumbens shell after exposure to a novel social stimulus. This effect of defeat was not observed in males. The effects of defeat in females were limited to social contexts, as there were no differences in exploratory behavior in the open field or light-dark box test. These data suggest that California mice could be a useful model for studying sex differences in behavioral responses to stress, particularly in neurobiological mechanisms that are involved with the regulation of social behavior.

Effectiveness of Parent-Child Interaction Therapy (PCIT) among Chinese Families

Science.gov (United States)

Leung, Cynthia; Tsang, Sandra; Heung, Kitty; Yiu, Ivan

2009-01-01

Objective: This study examined the effectiveness of Parent-Child Interaction Therapy (PCIT) among Chinese parents and children in Hong Kong with significant behavior problems. Method: The participants (intervention group, 48; comparison group, 62) completed questionnaires on child behavior problems and parenting stress before and after…

Interactions Between Stress and Sex in Microbial Responses Within the Microbiota-Gut-Brain Axis in a Mouse Model.

Science.gov (United States)

Tsilimigras, Matthew C B; Gharaibeh, Raad Z; Sioda, Michael; Gray, Laura; Fodor, Anthony A; Lyte, Mark

2018-05-01

Animal models are frequently used to examine stress response, but experiments seldom include females. The connection between the microbiota-gut-brain axis and behavioral stress response is investigated here using a mixed-sex mouse cohort. CF-1 mice underwent alternating days of restraint and forced swim for 19 days (male n = 8, female n = 8) with matching numbers of control animals at which point the 16S rRNA genes of gut microbiota were sequenced. Mixed linear models accounting for stress status and sex with individuals nested in cage to control for cage effects evaluated these data. Murine behaviors in elevated plus-maze, open-field, and light/dark box were investigated. Community-level associations with sex, stress, and their interaction were significant. Males had higher microbial diversity than females (p = .025). Of the 638 operational taxonomic units detected in at least 25% of samples, 94 operational taxonomic units were significant: 31 (stress), 61 (sex), and 34 (sex-stress interaction). Twenty of the 39 behavioral measures were significant for stress, 3 for sex, and 6 for sex-stress. However, no significant associations between behavioral measures and specific microbes were detected. These data suggest sex influences stress response and the microbiota-gut-brain axis and that studies of behavior and the microbiome therefore benefit from consideration of how sex differences drive behavior and microbial community structure. Host stress resilience and absence of associations between stress-induced behaviors with specific microbes suggests that hypothalamic-pituitary-adrenal axis activation represents a threshold for microbial influence on host behavior. Future studies are needed in examining the intersection of sex, stress response, and the microbiota-gut-brain axis.

The interplay of stress and mowing disturbance for the intensity and importance of plant interactions in dry calcareous grasslands.

Science.gov (United States)

Maalouf, Jean-Paul; Le Bagousse-Pinguet, Yoann; Marchand, Lilian; Touzard, Blaise; Michalet, Richard

2012-09-01

There is still debate regarding the direction and strength of plant interactions under intermediate to high levels of stress. Furthermore, little is known on how disturbance may interact with physical stress in unproductive environments, although recent theory and models have shown that this interplay may induce a collapse of plant interactions and diversity. The few studies assessing such questions have considered the intensity of biotic interactions but not their importance, although this latter concept has been shown to be very useful for understanding the role of interactions in plant communities. The objective of this study was to assess the interplay between stress and disturbance for plant interactions in dry calcareous grasslands. A field experiment was set up in the Dordogne, southern France, where the importance and intensity of biotic interactions undergone by four species were measured along a water stress gradient, and with and without mowing disturbance. The importance and intensity of interactions varied in a very similar way along treatments. Under undisturbed conditions, plant interactions switched from competition to neutral with increasing water stress for three of the four species, whereas the fourth species was not subject to any significant biotic interaction along the gradient. Responses to disturbance were more species-specific; for two species, competition disappeared with mowing in the wettest conditions, whereas for the two other species, competition switched to facilitation with mowing. Finally, there were no significant interactions for any species in the disturbed and driest conditions. At very high levels of stress, plant performances become too weak to allow either competition or facilitation and disturbance may accelerate the collapse of interactions in dry conditions. The results suggest that the importance and direction of interactions are more likely to be positively related in stressful environments.

Leadership styles and occupational stress among college athletic directors: the moderating effect of program goals.

Science.gov (United States)

Ryska, Todd A

2002-03-01

The interaction between an individual's abilities and the perceived demands of the workplace appears to make a unique contribution to job-related stress above and beyond that of dispositional or situational factors alone (R. S. Lazarus, 1990). In the present study, the author evaluated this contention among 245 male intercollegiate athletic directors by assessing the combined influence of leadership style and program goals on occupational stress. Regression analyses revealed the presence of both significant main effects and interaction effects of leadership style and program goals in the prediction of emotional exhaustion, daily job stress, and personal accomplishment. Findings are discussed in terms of person-environment fit theory (J. R. P. French, R. D. Caplan, & R. V. Harrison, 1982) and the notion of perceived control within the occupational setting.

The stressed eyewitness: the interaction of thematic arousal and post-event stress in memory for central and peripheral event information

OpenAIRE

Echterhoff, Gerald; Wolf, Oliver T.

2012-01-01

Both arousal during the encoding of stimuli and subsequent stress can affect memory, often by increasing memory for important or central information. We explored whether event-based (thematic) arousal and post-event stress interact to selectively enhance eyewitnesses' memory for the central aspects of an observed incident. Specifically, we argue that memory for stimuli should be enhanced when (1) the stimuli are encoded under arousal (vs. non-arousal), and (2) stress is experienced soon after...

Abscisic acid regulates root growth under osmotic stress conditions via an interacting hormonal network with cytokinin, ethylene and auxin.

Science.gov (United States)

Rowe, James H; Topping, Jennifer F; Liu, Junli; Lindsey, Keith

2016-07-01

Understanding the mechanisms regulating root development under drought conditions is an important question for plant biology and world agriculture. We examine the effect of osmotic stress on abscisic acid (ABA), cytokinin and ethylene responses and how they mediate auxin transport, distribution and root growth through effects on PIN proteins. We integrate experimental data to construct hormonal crosstalk networks to formulate a systems view of root growth regulation by multiple hormones. Experimental analysis shows: that ABA-dependent and ABA-independent stress responses increase under osmotic stress, but cytokinin responses are only slightly reduced; inhibition of root growth under osmotic stress does not require ethylene signalling, but auxin can rescue root growth and meristem size; osmotic stress modulates auxin transporter levels and localization, reducing root auxin concentrations; PIN1 levels are reduced under stress in an ABA-dependent manner, overriding ethylene effects; and the interplay among ABA, ethylene, cytokinin and auxin is tissue-specific, as evidenced by differential responses of PIN1 and PIN2 to osmotic stress. Combining experimental analysis with network construction reveals that ABA regulates root growth under osmotic stress conditions via an interacting hormonal network with cytokinin, ethylene and auxin. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Effect of Magnetostatic Interactions on Twin Boundary Motion in NiMnGa Magnetic Shape Memory Alloy

DEFF Research Database (Denmark)

Heczko, Oleg; Vokoun, David; Kopecky, Vit

2015-01-01

on the initial position of the twin boundary, the magnetic field providing the critical stress varied in the range 832 kA/m. By taking into account the variants sizes and their mutual interactions, we explained the observed dependence of the switching field on the location of the boundary. The resulting match......We investigated the effect of magnetostatic interactions on the field-induced reorientation of martensite variants in Ni50.0Mn27.5Ga22.5. The reorientation, achieved by sweeping a single Type-II twin boundary along the sample, was triggered by a twinning stress of about 0.1 MPa. However, depending...... between model predictions and measurements illustrates the fundamental role played by demagnetization effects and magnetostatic interactions in magnetic shape memory effect....

β-endorphin modulates the effect of stress on novelty-suppressed feeding

Directory of Open Access Journals (Sweden)

Elizabeth T. Barfield

2013-03-01

Full Text Available Although stress is implicated in the pathophysiology of mood and anxiety disorders, not all individuals who suffer stressful life events develop psychopathology. Differential susceptibility to stress may be influenced by genetically-mediated differences in hypothalamic-pituitary-adrenal (HPA axis activity and moderation of the stress response by the opioid peptide β-endorphin (β-E. The present study investigated genetic contributions to coping behavior by examining anxious behavior of transgenic mice with varying capacities to synthesize β-E (B6.129S2-Pomctm1Low/J; regulated by insertion of a premature stop codon into one or both copies of the proopiomelanocortin gene, both under normal conditions and following 3 minutes of forced swim. Ten minutes after this stress exposure or a control manipulation, acutely food-deprived female and male transgenic mice were subjected to a novelty-suppressed feeding (NSF test, during which their interaction with an almond slice located in the center of an open field box was measured. There was an interaction between genotype and stress for latency to approach the almond and whether or not the almond was approached, such that mice with low or absent β-E displayed a stronger aversion to novelty-feeding after stress exposure than did mice with normal levels. These data provide evidence for a moderating effect of β-E on the behavioral response to stress. Genotypic differences in anxious behavior emerged when mice were stressed prior to behavioral assessment, suggesting that β-E plays a role in coping behavior. These findings indicate that genetic variability in sensitivity of the β-E system to stress may contribute, at least in part, to heritable differences in stress reactivity as well as vulnerability to stress-related psychopathology.

Orexin signaling during social defeat stress influences subsequent social interaction behaviour and recognition memory.

Science.gov (United States)

Eacret, Darrell; Grafe, Laura A; Dobkin, Jane; Gotter, Anthony L; Rengerb, John J; Winrow, Christopher J; Bhatnagar, Seema

2018-06-11

Orexins are neuropeptides synthesized in the lateral hypothalamus that influence arousal, feeding, reward pathways, and the response to stress. However, the role of orexins in repeated stress is not fully characterized. Here, we examined how orexins and their receptors contribute to the coping response during repeated social defeat and subsequent anxiety-like and memory-related behaviors. Specifically, we used Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) to stimulate orexins prior to each of five consecutive days of social defeat stress in adult male rats. Additionally, we determined the role of the orexin 2 receptor in these behaviors by using a selective orexin 2 receptor antagonist (MK-1064) administered prior to each social defeat. Following the 5 day social defeat conditioning period, rats were evaluated in social interaction and novel object recognition paradigms to assess anxiety-like behavior and recognition memory, respectively. Activation of orexin neurons by DREADDs prior to each social defeat decreased the average latency to become defeated across 5 days, indicative of a passive coping strategy that we have previously linked to a stress vulnerable phenotype. Moreover, stimulation of orexin signaling during defeat conditioning decreased subsequent social interaction and performance in the novel object recognition test indicating increased subsequent anxiety-like behavior and reduced working memory. Blocking the orexin 2 receptor during repeated defeat did not alter these effects. Together, our results suggest that orexin neuron activation produces a passive coping phenotype during social defeat leading to subsequent anxiety-like behaviors and memory deficits. Copyright © 2018. Published by Elsevier B.V.

Interactive effects of dietary restraint and adiposity on stress-induced eating and the food choice of children

Science.gov (United States)

The Individual Differences Model posits that individual differences in physiological and psychological factors explain eating behaviors in response to stress. The purpose was to determine the effects of individual differences in adiposity, dietary restraint and stress reactivity on children's energy...

Stressed lungs: unveiling the role of circulating stress ...

Science.gov (United States)

Ozone, a major component of smog generated through the interaction of light and anthropogenic emissions, induces adverse pulmonary, cardiovascular, and systemic health effects upon inhalation. It is generally accepted that ozone-induced lung injury is mediated by its interaction with lung lining components causing local oxidative changes, which then leads to cell damage and recruitment of inflammatory cells. It is postulated that the spillover of reactive intermediates and pro-inflammatory molecules from lung to systemic circulation mediates extra-pulmonary effects. However, recent work from our laboratory supports an alternative hypothesis that circulating stress hormones, such as epinephrine and corticosterone/cortisol, are involved in mediating ozone pulmonary effects. We have shown in rats and humans that ozone increases the levels of circulating stress hormones through activation of the hypothalamus- pituitary-adrenal (HPA) axis before any measurable effects are observed in the lung. The surgical removal of adrenals diminishes circulating stress hormones and at the same time, the pulmonary effects of ozone suggesting a significant contribution of these hormones in ozone-induced lung injury and inflammation. While ozone effects in the lung have been extensively studied, the contribution of central nervous system -mediated hormonal stress response has not been examined. In order to understand the signaling pathways that might be involved in ozone-induced lun

Effects of environmental stress on forest crown condition in Europe. Part IV statistical analysis of relationships

NARCIS (Netherlands)

Klap, J.M.; Oude Voshaar, J.H.; Vries, de W.; Erisman, J.W.

2000-01-01

Site-specific estimates for various environmental stress factors were related with measured crown condition data at a systematic 16 x: 16 km(2) grid over Europe, according to previously stated hypotheses, using a multiple regression approach, including interactions, and lagged effects of stress

Characteristics of aperiodic sequence of slip events caused by interaction between seismic patches and that caused be self-organized stress heterogeneity

Science.gov (United States)

Kato, N.

2017-12-01

Numerical simulations of earthquake cycles are conducted to investigate the origin of complexity of earthquake recurrence. There are two main causes of the complexity. One is self-organized stress heterogeneity due to dynamical effect. The other is the effect of interaction between some fault patches. In the model, friction on the fault is assumed to obey a rate- and state-dependent friction law. Circular patches of velocity-weakening frictional property are assumed on the fault. On the remaining areas of the fault, velocity-strengthening friction is assumed. We consider three models: Single patch model, two-patch model, and three-patch model. In the first model, the dynamical effect is mainly examined. The latter two models take into consideration the effect of interaction as well as the dynamical effect. Complex multiperiodic or aperiodic sequences of slip events occur when slip behavior changes from the seismic to aseismic, and when the degree of interaction between seismic patches is intermediate. The former is observed in all the models, and the latter is observed in the two-patch model and the three-patch model. Evolution of spatial distribution of shear stress on the fault suggests that aperiodicity at the transition from seismic to aseismic slip is caused by self-organized stress heterogeneity. The iteration maps of recurrence intervals of slip events in aperiodic sequences are examined, and they are approximately expressed by simple curves for aperiodicity at the transition from seismic to aseismic slip. In contrast, the iteration maps for aperiodic sequences caused by interaction between seismic patches are scattered and they are not expressed by simple curves. This result suggests that complex sequences caused by different mechanisms may be distinguished.

Effects of Stress and Task Difficulty on Working Memory and Cortical Networking.

Science.gov (United States)

Kim, Yujin; Woo, Jihwan; Woo, Minjung

2017-12-01

This study investigated interactive effects of stress and task difficulty on working memory and cortico-cortical communication during memory encoding. Thirty-eight adolescent participants (mean age of 15.7 ± 1.5 years) completed easy and hard working memory tasks under low- and high-stress conditions. We analyzed the accuracy and reaction time (RT) of working memory performance and inter- and intrahemispheric electroencephalogram coherences during memory encoding. Working memory accuracy was higher, and RT shorter, in the easy versus the hard task. RT was shorter under the high-stress (TENS) versus low-stress (no-TENS) condition, while there was no difference in memory accuracy between the two stress conditions. For electroencephalogram coherence, we found higher interhemispheric coherence in all bands but only at frontal electrode sites in the easy versus the hard task. On the other hand, intrahemispheric coherence was higher in the left hemisphere in the easy (versus hard task) and higher in the right hemisphere (with one exception) in the hard (versus easy task). Inter- and intracoherences were higher in the low- versus high-stress condition. Significant interactions between task difficulty and stress condition were observed in coherences of the beta frequency band. The difference in coherence between low- and high-stress conditions was greater in the hard compared with the easy task, with lower coherence under the high-stress condition relative to the low-stress condition. Stress seemed to cause a decrease in cortical network communications between memory-relevant cortical areas as task difficulty increased.

Daily Social Interactions and the Biological Stress Response: Are There Age Differences in Links Between Social Interactions and Alpha-Amylase?

Science.gov (United States)

Birditt, Kira S; Tighe, Lauren A; Nevitt, Michael R; Zarit, Steven H

2017-12-12

According to the strength and vulnerability integration (SAVI) model, older people are better able to avoid negative social interactions than younger people, but when they do experience negative interactions, they are equally or more emotionally and physiologically reactive than younger people. Less is known about the links between daily negative and positive social encounters and the sympathetic adrenal medullary system (a key stress pathway) and whether there are age differences in these links. This study considers whether negative and positive social interactions are associated with diurnal alpha-amylase (a measure of the sympathetic adrenal medullary system) and whether there are differences in these links by age. Participants were from the Daily Health, Stress, and Relationship Study, which includes a random sample of 89 individuals (aged 40-95) who completed 14 days of daily diary interviews and provided saliva samples four times a day (wake, 30 min after wake, lunch, and bedtime) for four of those days that were assayed for alpha-amylase. Days in which people reported more negative interactions were associated with flatter morning declines in alpha-amylase, indicating greater stress. Links between positive interactions and diurnal alpha-amylase varied by age group. Findings are consistent with the SAVI model indicating that older adults respond differently to social stimuli than younger people. © The Author(s) 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Interactive effects of rice residue and water stress on growth and metabolism of wheat seedlings

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Nimisha Amist

2014-08-01

Full Text Available In the present study effects of rice residue with and without water stress were studied on Triticum aestivum L. cv. Shatabadi. The mixture of residue and garden soil in 1:1 ratio was considered as 50% (R1 and only decomposed residue as 100% (R2. Garden soil was taken as control. Twenty five seeds were sown in each experimental trays filled with soil mixture according to the treatments. Trays were arranged in two groups. After 15 days one set was subjected to water stress (WS by withholding water supply for 3 days. Morphological and biochemical parameters of 18 days old seedlings were recorded. Seedling height decreased in all treatments. A gradual decrease in relative water content, pigment and protein contents of wheat seedlings were observed. Sugar and proline contents increased in treatments. An increase in malondialdehyde (MDA content and antioxidative enzyme activities was recorded. Elevation in catalase activity was observed in all treatments except in plants with water deficit. Ascorbate peroxidase (APX and guaiacol peroxidase (GPX activities increased when residue mixed with soil but decreased in seedlings under the combined influence of the residue and water stress. Higher amount of MDA and lower activities of APX and GPX reflected the oxidative damage in seedlings under combined treatments. Rice residue inhibited growth of wheat seedlings. Water stress intensified the effects of residue.

Relationship Between Intrinsic Motivation and Undergraduate Students' Depression and Stress: The Moderating Effect of Interpersonal Conflict.

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Huang, Yunhui; Lv, Wei; Wu, Jiang

2016-10-01

This study examined the effect of intrinsic academic motivation and interpersonal conflict on the perceived depression and stress. Participants were 537 Chinese undergraduate students (191 males and 346 females; M age = 20.4 years, SD age = 1.3). They completed four scales measuring intrinsic academic motivation, interpersonal conflict, stress, and depression. Linear regressions were conducted with intrinsic academic motivation, interpersonal conflict, and their interaction as independent variables to predict depression and stress. Results showed that intrinsic academic motivation was negatively, while interpersonal conflict was positively, associated with depression and stress. Moreover, the interaction was significant: negative association of "intrinsic academic motivation and depression" and that of "intrinsic academic motivation and stress" was weaker among participants who reported higher (vs. lower) levels of interpersonal conflict. © The Author(s) 2016.

Reduced endothelial thioredoxin-interacting protein protects arteries from damage induced by metabolic stress in vivo.

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Bedarida, Tatiana; Domingues, Alison; Baron, Stephanie; Ferreira, Chrystophe; Vibert, Francoise; Cottart, Charles-Henry; Paul, Jean-Louis; Escriou, Virginie; Bigey, Pascal; Gaussem, Pascale; Leguillier, Teddy; Nivet-Antoine, Valerie

2018-06-01

Although thioredoxin-interacting protein (TXNIP) is involved in a variety of biologic functions, the contribution of endothelial TXNIP has not been well defined. To investigate the endothelial function of TXNIP, we generated a TXNIP knockout mouse on the Cdh5-cre background (TXNIP fl/fl cdh5 cre ). Control (TXNIP fl/fl ) and TXNIP fl/fl cdh5 cre mice were fed a high protein-low carbohydrate (HP-LC) diet for 3 mo to induce metabolic stress. We found that TXNIP fl/fl and TXNIP fl/fl cdh5 cre mice on an HP-LC diet displayed impaired glucose tolerance and dyslipidemia concretizing the metabolic stress induced. We evaluated the impact of this metabolic stress on mice with reduced endothelial TXNIP expression with regard to arterial structure and function. TXNIP fl/fl cdh5 cre mice on an HP-LC diet exhibited less endothelial dysfunction than littermate mice on an HP-LC diet. These mice were protected from decreased aortic medial cell content, impaired aortic distensibility, and increased plasminogen activator inhibitor 1 secretion. This protective effect came with lower oxidative stress and lower inflammation, with a reduced NLRP3 inflammasome expression, leading to a decrease in cleaved IL-1β. We also show the major role of TXNIP in inflammation with a knockdown model, using a TXNIP-specific, small interfering RNA included in a lipoplex. These findings demonstrate a key role for endothelial TXNIP in arterial impairments induced by metabolic stress, making endothelial TXNIP a potential therapeutic target.-Bedarida, T., Domingues, A., Baron, S., Ferreira, C., Vibert, F., Cottart, C.-H., Paul, J.-L., Escriou, V., Bigey, P., Gaussem, P., Leguillier, T., Nivet-Antoine, V. Reduced endothelial thioredoxin-interacting protein protects arteries from damage induced by metabolic stress in vivo.

Reward anticipation modulates the effect of stress-related increases in cortisol on episodic memory.

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Quent, Jörn A; McCullough, Andrew M; Sazma, Matt; Wolf, Oliver T; Yonelinas, Andrew P

2018-01-01

When acute stress is experienced shortly after an event is encoded into memory, this can slow the forgetting of the study event, which is thought to reflect the effect of cortisol on consolidation. In addition, when events are encoded under conditions of high reward they tend to be remembered better than those encoded under non-rewarding conditions, and these effects are thought to reflect the operation of the dopaminergic reward system. Although both modulatory systems are believed to impact the medial temporal lobe regions critical for episodic memory, the manner, and even the extent, to which these two systems interact is currently unknown. To address this question in the current study, participants encoded words under reward or non-reward conditions, then one half of the participants were stressed using the social evaluation cold pressor task and the other half completed a non-stress control task. After a two-hour delay, all participants received a free recall and recognition memory test. There were no significant effects of stress or reward on overall memory performance. However, for the non-reward items, increases in stress-related cortisol in stressed participants were related to increases in recall and increases in recollection-based recognition responses. In contrast, for the reward items, increases in stress-related cortisol were not related to increases in memory performance. The results indicate that the stress and the reward systems interact in the way they impact episodic memory. The results are consistent with tag and capture models in the sense that cortisol reactivity can only affect non-reward items because plasticity-related products are already provided by reward anticipation. Copyright © 2017 Elsevier Inc. All rights reserved.

A 667 year record of coseismic and interseismic Coulomb stress changes in central Italy reveals the role of fault interaction in controlling irregular earthquake recurrence intervals

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Wedmore, L. N. J.; Faure Walker, J. P.; Roberts, G. P.; Sammonds, P. R.; McCaffrey, K. J. W.; Cowie, P. A.

2017-07-01

Current studies of fault interaction lack sufficiently long earthquake records and measurements of fault slip rates over multiple seismic cycles to fully investigate the effects of interseismic loading and coseismic stress changes on the surrounding fault network. We model elastic interactions between 97 faults from 30 earthquakes since 1349 A.D. in central Italy to investigate the relative importance of co-seismic stress changes versus interseismic stress accumulation for earthquake occurrence and fault interaction. This region has an exceptionally long, 667 year record of historical earthquakes and detailed constraints on the locations and slip rates of its active normal faults. Of 21 earthquakes since 1654, 20 events occurred on faults where combined coseismic and interseismic loading stresses were positive even though 20% of all faults are in "stress shadows" at any one time. Furthermore, the Coulomb stress on the faults that experience earthquakes is statistically different from a random sequence of earthquakes in the region. We show how coseismic Coulomb stress changes can alter earthquake interevent times by 103 years, and fault length controls the intensity of this effect. Static Coulomb stress changes cause greater interevent perturbations on shorter faults in areas characterized by lower strain (or slip) rates. The exceptional duration and number of earthquakes we model enable us to demonstrate the importance of combining long earthquake records with detailed knowledge of fault geometries, slip rates, and kinematics to understand the impact of stress changes in complex networks of active faults.

The interaction between dietary Fe, Cu and stress in Cu-67 retention and serum ceruloplasmin (Cp) activity in rats

International Nuclear Information System (INIS)

Pellett, L.; Kattelmann, K.; Zinn, K.; Trokey, D.; Forrester, I.; Gordon, D.T.

1991-01-01

The objectives of the study were to determine the effects of dietary Fe and stress on Cu-67 retention and serum Cp activity in the rat. A 2 x 2 x 2 factorial arrangement of treatments was utilized. Male Sprague Dawley weanling rats were fed AIN-76 diets ad lib containing 0.8 ppm Cu (CuD) or 5.7 ppm Cu (CuA) with 22.5 ppm Fe (FeA) or 280 ppm Fe (FeE). After 19 days, one-half of the animals of each treatment were stressed by an intramuscular injection of 0.1 ml turpentine/100 gm body weight. Forty-eight hours later, animals were gavaged with Cu-67 and counted over a 7 day period in a whole body high resolution gamma counter. Cu-67 retention was 20% higher in CuD rats compared to CuA rats. There were no significant effects caused by Fe or stress or the interaction between these variables on Cu-67 retention. In rats fed FeE-CuA diets, serum Cp activity was significantly depressed compared to rats fed FeA-CuA diets. These reductions in the acute phase protein Cp, were 85% and 70% in nonstressed and stressed rats, respectively. The results of this study suggest that the negative interaction effects of excess Fe on Cu utilization does not occur at the site of Cu absorption, but within the body and specifically in the liver

Interactive effects of salinity stress and nicotinamide on physiological and biochemical parameters of Faba bean plant

International Nuclear Information System (INIS)

Abdelhamid, Magdi T; Sadak, Mervat Sh; Schmidhalter, Urs; El Saady, Abdel Kareem M.

2013-01-01

A possible survival strategy for plants under saline conditions is to use some compounds that could alleviate the salt stress effect. One of these compounds is nicotinamide (vitamin B3/niacin). The effect of exogenous application of nicotinamide with different concentrations (0,200 or 400 mg l-1) on faba bean (Vicia faba L.) plant grown at different NaCl levels (0,50 or 100 mM) was investigated in the wire house of the National Research Centre, Cairo, Egypt. Salinity stress significantly reduced the photosynthetic pigments, polysaccharides, total carbohydrates, total-N contents of shoot, plant height, leaves number, fresh and dry weights of shoot, seed yield, total carbohydrates and total crude protein of the yielded seeds compared with those of the control plants. In contrast, salinity induced marked increases in sucrose, total soluble sugars, total free amino acids, proline, lipid peroxidation product (MDA) and some oxidative enzymes (polyphenol-oxidase and peroxidase). Also, salinity stress increased Na+ contents with the decreases of other macro and micro elements contents (P, K+, Mg_2+, Ca_2+, Fe_2+, Mn_2+, Zn_2+ and Cu_2+) of shoots and the yielded seeds of faba bean. Foliar spraying of nicotinamide alleviated the adverse effects of salinity stress through increased the photosynthetic pigments, polysaccharides, total carbohydrates, total N concentration of shoot, plant height, leaves number, fresh and dry weights of shoot, and seed yield as well as, sucrose, total soluble sugars, total free amino acids and proline, compared with those of the corresponding salinity levels, while decreased lipid peroxidation product as malondialdehyde (MDA) and the oxidative enzymes (polyphenol oxidase and peroxidase enzymes). Nicotinamide inhibited the uptake of Na+ and accelerated the accumulation of P, K+, Mg_2+, Ca_2+, Fe_2+, Mn_2+, Zn_2+ and Cu_2+ concentrations in the shoots of salt stressed plants and enhanced total carbohydrate and total crude protein percentage and

Serotonin Transporter-Linked Polymorphic Region (5-HTTLPR) Genotype and Stressful Life Events Interact to Predict Preschool-Onset Depression: A Replication and Developmental Extension

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Bogdan, Ryan; Agrawal, Arpana; Gaffrey, Michael S.; Tillman, Rebecca; Luby, Joan L.

2014-01-01

Background: Scientific enthusiasm about gene × environment interactions, spurred by the 5-HTTLPR (serotonin transporter-linked polymorphic region) × SLEs (stressful life events) interaction predicting depression, have recently been tempered by sober realizations of small effects and meta-analyses reaching opposing conclusions. These mixed findings…

Circadian Clocks and the Interaction between Stress Axis and Adipose Function

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Isa Kolbe

2015-01-01

Full Text Available Many physiological processes and most endocrine functions show fluctuations over the course of the day. These so-called circadian rhythms are governed by an endogenous network of cellular clocks and serve as an adaptation to daily and, thus, predictable changes in the organism’s environment. Circadian clocks have been described in several tissues of the stress axis and in adipose cells where they regulate the rhythmic and stimulated release of stress hormones, such as glucocorticoids, and various adipokine factors. Recent work suggests that both adipose and stress axis clock systems reciprocally influence each other and adrenal-adipose rhythms may be key players in the development and therapy of metabolic disorders. In this review, we summarize our current understanding of adrenal and adipose tissue rhythms and clocks and how they might interact to regulate energy homoeostasis and stress responses under physiological conditions. Potential chronotherapeutic strategies for the treatment of metabolic and stress disorders are discussed.

The γ-ε martensitic transformation: a model for stress induced variant and its interaction with grain boundary

International Nuclear Information System (INIS)

Guenin, G.

1995-01-01

The γ (f.c.c.) to ε (h.c.p.) martensitic transformation occurs through the Shockley a/6 left angle 211 right angle faulting every second {111} plane of the f.c.c. structure. A stress induced thin single variant corresponds to a single a/6 left angle 211 right angle faulting vector and leads to a large homogeneous shear (0.35) in amplitude. The tip of such a plate is composed of a set of identical Shockley partial dislocations with large mutual interactions. This work is a presentation of a model which describes the martensite morphology of stress induced ε martensite in shape memory Fe-Mn-Si based alloys. The model includes the formation mechanism of the plate (Seeger's like) and its growth inside a limited grain. The mutual interaction of Shockley dislocations and their interaction with the grain boundary is semi quantitatively described; it leads to a lenticular shape of ε martensite thin plates. The model is able to explain the behaviour of this kind of alloys concerning the superelastic effect and the shape memory. (orig.)

The effectiveness of cognitive behavioral stress management training on mental health, social interaction and family function in adolescents of families with one Human Immunodeficiency Virus (HIV) positive member.

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Keypour, Maryam; Arman, Soroor; Maracy, Mohammad Reza

2011-06-01

This study evaluated stress management training to improve mental health, social interaction and family function among adolescents of families with one Human Immunodeficiency Virus (HIV) positive member. There were 34 adolescents (13-18 years old) with at least one family member living with HIV from whom finally 15 attended the study and participated in 8 weekly sessions of stress management training. The tests used in this study were: Strengths and Difficulties Questionnaire (self and parent report), General Health Questionnare-28 (GHQ-28) and Family Assessment Device (FAD), conducted before, after and three months after the intervention. The collected data were analyzed by repeated measure test using SPSS software (Version 18.0). Adolescents with one HIV positive family member showed high level of emotional problem (40%) and conduct problem (33.3%). There was a significant difference between before, after and 3months after intervention based on GHQ-28 mean scores and FAD mean sores (p social behavior based on SDQ (self report and parents report forms) in all three stages (before, after and three months after intervention). Stress management training is effective in improving mental health, family function and social interaction among adolescents living with parents infected with HIV/AIDS.

Agreeableness, Extraversion, Stressor and Physiological Stress Response

OpenAIRE

Xiaoyuan Chu; Zhentao Ma; Yuan Li; Jing Han

2015-01-01

Based on the theoretical analysis, with first-hand data collection and using multiple regression models, this study explored the relationship between agreeableness, extraversion, stressor and stress response and figured out interactive effect of agreeableness, extraversion, and stressor on stress response. We draw on the following conclusions: (1) the interaction term of stressor (work) and agreeableness can negatively predict physiological stress response; (2) the interaction term of stresso...

Neuroprotective mechanism of losartan and its interaction with nimesulide against chronic fatigue stress.

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Kumar, Anil; Singh, Barinder; Mishra, Jitendriya; Sah, Sangeeta Pilkhwal; Pottabathini, Raghavender

2015-12-01

Potential role of angiotensin-II and cyclooxygenase have been suggested in the pathophysiology of chronic fatigue stress. The present study has been designed to evaluate the neuroprotective effect of losartan and its interaction with nimesulide against chronic fatigue stress and related complications in mice. In the present study, male Laca mice (20-30 g) were subjected to running wheel activity test session (RWATS) for 6 min daily for 21 days. Losartan, nimesulide and their combinations were administered daily for 21 days, 45 min before being subjected to RWATS. Various behavioral and biochemical and neuroinflammatory mediators were assessed subsequently. 21 days RWATS treatment significantly decreased number of wheel rotations/6 min indicating fatigue stress like behaviors as compared to naive group. 21 days treatment with losartan (10 and 20 mg/kg, ip), nimesulide (5 and 10 mg/kg, po) and their combinations significantly improved behavior [increased number of wheel rotations, reversal of post-exercise fatigue, locomotor activity, antianxiety-like behavior (number of entries, latency to enter and time spent in mirror chamber), and memory performance (transfer latency in plus-maze performance task)], biochemical parameters (reduced serum corticosterone, brain lipid peroxidation, nitrite concentration, acetylcholinesterase activity, restored reduced glutathione levels and catalase activity) as compared to RWATS control. Besides, TNF-α, CRP levels were significantly attenuated by these drugs and their combinations as compared to control. The present study highlights the role of cyclooxygenase modulation in the neuroprotective effect of losartan against chronic fatigue stress-induced behavioral, biochemical and cellular alterations in mice.

Genomewide Expression and Functional Interactions of Genes under Drought Stress in Maize

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Nepolean Thirunavukkarasu

2017-01-01

Full Text Available A genomewide transcriptome assay of two subtropical genotypes of maize was used to observe the expression of genes at seedling stage of drought stress. The number of genes expressed differentially was greater in HKI1532 (a drought tolerant genotype than in PC3 (a drought sensitive genotype, indicating primary differences at the transcriptional level in stress tolerance. The global coexpression networks of the two genotypes differed significantly with respect to the number of modules and the coexpression pattern within the modules. A total of 174 drought-responsive genes were selected from HKI1532, and their coexpression network revealed key correlations between different adaptive pathways, each cluster of the network representing a specific biological function. Transcription factors related to ABA-dependent stomatal closure, signalling, and phosphoprotein cascades work in concert to compensate for reduced photosynthesis. Under stress, water balance was maintained by coexpression of the genes involved in osmotic adjustments and transporter proteins. Metabolism was maintained by the coexpression of genes involved in cell wall modification and protein and lipid metabolism. The interaction of genes involved in crucial biological functions during stress was identified and the results will be useful in targeting important gene interactions to understand drought tolerance in greater detail.

How do Nutritional Stress and La Crosse Virus Infection Interact? Tests for Effects on Willingness to Blood Feed and Fecundity in Aedes albopictus (Diptera: Culicidae).

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Westby, Katie M; Muturi, Ephantus J; Juliano, Steven A

2016-01-01

Evolutionary theory predicts that vector-borne pathogens should have low virulence for their vector because of selection against pathogens that harm the vector sufficiently to reduce transmission. Environmental factors such as nutritional stress can alter vector-pathogen associations by making the vectors more susceptible to pathogens (condition-dependent competence) and vulnerable to the harm caused by pathogen replication (condition-dependent virulence). We tested the hypotheses of condition-dependent competence and condition-dependent virulence by examining the interactive effects of short-term sugar deprivation and exposure to La Crosse virus (LACV) in female Aedes albopictus (Skuse). We predicted that infection status interacts with sugar deprivation to alter willingness to blood feed and fecundity in the second gonotrophic cycle (condition-dependent virulence). Sugar deprivation had no effect on body infection or disseminated infection rates. Infection status, sugar treatment, and their interaction had no effect on fecundity. Mosquitoes that had intermittent access to sugar were significantly more willing to take a second bloodmeal compared with those that had continuous access to sugar. Infection status and the interaction with sugar treatment had no effect on blood-feeding behavior. Thus, we found no evidence of short-term sugar deprivation leading to condition-dependent competence for, or condition-dependent virulence of, LACV in Ae. albopictus. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Brain aromatase and circulating corticosterone are rapidly regulated by combined acute stress and sexual interaction in a sex specific manner

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Dickens, M.J.; Balthazart, J.; Cornil, C. A.

2012-01-01

Neural production of 17β-oestradiol via aromatisation of testosterone may play a critical role in rapid, non-genomic regulation of physiological and behavioural processes. In brain nuclei implicated in the control of sexual behaviour, sexual or stressfull stimuli induce respectively a rapid inhibition or increase in preoptic aromatase activity (AA). Here, we tested quail that were either non-stressed or acutely stressed (15 min restraint) immediately prior to sexual interaction (5 min) with stressed or non-stressed partners. We measured nuclei-specific AA changes, corresponding behavioural output, fertilisation rates and corticosterone (CORT) concentrations. In males, sexual interaction rapidly reversed stress-induced increases of AA in the medial preoptic nucleus (POM). This time scale (behaviour suggesting that the input from the sexual stimuli on POM AA may actively preserve sexual behaviour despite stress exposure. We also found distinct sex differences in contextual physiological responses: while males did not show any effect of partner status, females responded to both their stress exposure and the male partner’s stress exposure at the level of circulating CORT and AA. In addition, fertilisation rates and female CORT correlated with the male partner’s exhibition of sexually aggressive behaviour suggesting that female perception of the male can affect their physiology as much as direct stress. Overall, male reproduction appears relatively simple – sexual stimuli, irrespective of stress, drives major neural changes including rapid reversal of stress-induced changes of AA. In contrast, female reproduction appears more nuanced and context specific, with subjects responding physiologically and behaviourally to stress, the male partner’s stress exposure, and female-directed male behaviour. PMID:22612582

The Buffer Effect of Therapy Dog Exposure on Stress Reactivity in Undergraduate Students

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Alexandra J. Fiocco

2017-06-01

Full Text Available Stress is an insidious health risk that is commonly reported among university students. While research suggests that dog exposure may facilitate recovery from a stress response, little is known about the buffer effect of dog exposure on the stress response to a future stressor. This study examined whether interaction with a therapy dog could reduce the strength of the physiological stress response when exposed to a subsequent stressor. Sixty-one university students were randomly assigned to either a therapy dog (TD, n = 31 or a no-dog control (C, n = 30 group. The stress response was measured by electrodermal activity (EDA in response to the Paced Auditory Serial Addition Test (PASAT. Participants also completed questionnaires that assessed pet attitude, general stress levels, and affect. Analyses of covariance (ANCOVAs showed that increase in EDA was significantly more pronounced in the C group than in the TD group (p < 0.01. Pet attitudes did not modulate the buffer effect of therapy dog exposure. Results suggest that therapy dog exposure may buffer the stress response in university students, which has implications for the promotion of a viable stress management program on university campuses.

On crack interaction effects of in-plane surface cracks using elastic and elastic-plastic finite element analyses

International Nuclear Information System (INIS)

Kim, Jong Min; Huh, Nam Su

2010-01-01

The crack-tip stress fields and fracture mechanics assessment parameters for a surface crack, such as the elastic stress intensity factor or the elastic-plastic J-integral, can be affected significantly by the adjacent cracks. Such a crack interaction effect due to multiple cracks can alter the fracture mechanics assessment parameters significantly. There are many factors to be considered, for instance the relative distance between adjacent cracks, the crack shape, and the loading condition, to quantify the crack interaction effect on the fracture mechanics assessment parameters. Thus, the current assessment codes on crack interaction effects (crack combination rules), including ASME Sec. XI, BS7910, British Energy R6 and API 579-1/ASME FFS-1, provide different rules for combining multiple surface cracks into a single surface crack. The present paper investigates crack interaction effects by evaluating the elastic stress intensity factor and the elastic-plastic J-integral of adjacent in-plane surface cracks in a plate through detailed 3-dimensional elastic and elastic-plastic finite element analyses. The effects on the fracture mechanics assessment parameters of the geometric parameters, the relative distance between two cracks, and the crack shape are investigated systematically. As for the loading condition, an axial tension is considered. Based on the finite element results, the acceptability of the crack combination rules provided in the existing guidance was investigated, and the relevant recommendations on a crack interaction for in-plane surface cracks are discussed. The present results can be used to develop more concrete guidance on crack interaction effects for crack shape characterization to evaluate the integrity of defective components

Diazepam-stress interactions in the rat: effects on autoanalgesia and a plus-maze model of anxiety.

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Taukulis, H K; Goggin, C E

1990-03-01

On six occasions spaced at least a week apart, two groups of rats were subjected to a variety of stressful conditions consisting of a restraint/bright light complex, either alone or in combination with a tail pinch, whole-body inversion, or partial immersion in cold water. One of these groups was injected with diazepam (2.0 mg/kg) 30 min prior to the stressors, while the other group experienced the drug in their home cages the following day. A third group also received the diazepam but was not exposed to the stressors. In three test sessions all animals were injected with either diazepam or saline and were then exposed to a novel stressor: a plus-maze used as a screening device for anxiolytic drugs. This was immediately followed by a tail-flick measure of analgesia. The longest tail-flick latencies, indicating stress-induced analgesia ("autoanalgesia"), were observed in the group that had not been exposed to stress prior to testing. The other two groups exhibited substantially shorter latencies but did not differ from one another, thus showing a "stress inoculation" effect that was uninfluenced by diazepam. In the plus-maze, diazepam tends to increase the amount of time rats will spend in the two exposed arms of the maze relative to the two enclosed arms. This effect was significantly attenuated in the group that had previously experienced the variety of stressors after a diazepam injection, suggesting a learned association between drug and stress that resulted in a diminution of the drug's anxiolytic property.

Toxic Stress: Effects, Prevention and Treatment

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Hillary A. Franke

2014-11-01

Full Text Available Children who experience early life toxic stress are at risk of long-term adverse health effects that may not manifest until adulthood. This article briefly summarizes the findings in recent studies on toxic stress and childhood adversity following the publication of the American Academy of Pediatrics (AAP Policy Report on the effects of toxic stress. A review of toxic stress and its effects is described, including factors of vulnerability, resilience, and the relaxation response. An integrative approach to the prevention and treatment of toxic stress necessitates individual, community and national focus.

Parenting Stress, Social Support, and Mother-Child Interactions in Families of Multiple and Singleton Preterm Toddlers

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Lutz, Kristin F.; Burnson, Cynthia; Hane, Amanda; Samuelson, Anne; Maleck, Sarah; Poehlmann, Julie

2012-01-01

The study investigated family support as a buffer of stress in 153 mothers and preterm toddlers. Data were collected regarding maternal depressive symptoms, parenting stress, and family support; infant health; and videotaped mother-child interactions. Although more parenting stress related to less optimal child play, only information support…

A Multi-Phase Based Fluid-Structure-Microfluidic interaction sensor for Aerodynamic Shear Stress

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Hughes, Christopher; Dutta, Diganta; Bashirzadeh, Yashar; Ahmed, Kareem; Qian, Shizhi

2014-11-01

A novel innovative microfluidic shear stress sensor is developed for measuring shear stress through multi-phase fluid-structure-microfluidic interaction. The device is composed of a microfluidic cavity filled with an electrolyte liquid. Inside the cavity, two electrodes make electrochemical velocimetry measurements of the induced convection. The cavity is sealed with a flexible superhydrophobic membrane. The membrane will dynamically stretch and flex as a result of direct shear cross-flow interaction with the seal structure, forming instability wave modes and inducing fluid motion within the microfluidic cavity. The shear stress on the membrane is measured by sensing the induced convection generated by membrane deflections. The advantages of the sensor over current MEMS based shear stress sensor technology are: a simplified design with no moving parts, optimum relationship between size and sensitivity, no gaps such as those created by micromachining sensors in MEMS processes. We present the findings of a feasibility study of the proposed sensor including wind-tunnel tests, microPIV measurements, electrochemical velocimetry, and simulation data results. The study investigates the sensor in the supersonic and subsonic flow regimes. Supported by a NASA SBIR phase 1 contract.

Reactive Oxygen Species Generation-Scavenging and Signaling during Plant-Arbuscular Mycorrhizal and Piriformospora indica Interaction under Stress Condition.

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Nath, Manoj; Bhatt, Deepesh; Prasad, Ram; Gill, Sarvajeet S; Anjum, Naser A; Tuteja, Narendra

2016-01-01

A defined balance between the generation and scavenging of reactive oxygen species (ROS) is essential to utilize ROS as an adaptive defense response of plants under biotic and abiotic stress conditions. Moreover, ROS are not only a major determinant of stress response but also act as signaling molecule that regulates various cellular processes including plant-microbe interaction. In particular, rhizosphere constitutes the biologically dynamic zone for plant-microbe interactions which forms a mutual link leading to reciprocal signaling in both the partners. Among plant-microbe interactions, symbiotic associations of arbuscular mycorrhizal fungi (AMF) and arbuscular mycorrhizal-like fungus especially Piriformospora indica with plants are well known to improve plant growth by alleviating the stress-impacts and consequently enhance the plant fitness. AMF and P. indica colonization mainly enhances ROS-metabolism, maintains ROS-homeostasis, and thereby averts higher ROS-level accrued inhibition in plant cellular processes and plant growth and survival under stressful environments. This article summarizes the major outcomes of the recent reports on the ROS-generation, scavenging and signaling in biotic-abiotic stressed plants with AMF and P. indica colonization. Overall, a detailed exploration of ROS-signature kinetics during plant-AMF/ P. indica interaction can help in designing innovative strategies for improving plant health and productivity under stress conditions.

Random regression models to account for the effect of genotype by environment interaction due to heat stress on the milk yield of Holstein cows under tropical conditions.

Science.gov (United States)

Santana, Mário L; Bignardi, Annaiza Braga; Pereira, Rodrigo Junqueira; Menéndez-Buxadera, Alberto; El Faro, Lenira

2016-02-01

The present study had the following objectives: to compare random regression models (RRM) considering the time-dependent (days in milk, DIM) and/or temperature × humidity-dependent (THI) covariate for genetic evaluation; to identify the effect of genotype by environment interaction (G×E) due to heat stress on milk yield; and to quantify the loss of milk yield due to heat stress across lactation of cows under tropical conditions. A total of 937,771 test-day records from 3603 first lactations of Brazilian Holstein cows obtained between 2007 and 2013 were analyzed. An important reduction in milk yield due to heat stress was observed for THI values above 66 (-0.23 kg/day/THI). Three phases of milk yield loss were identified during lactation, the most damaging one at the end of lactation (-0.27 kg/day/THI). Using the most complex RRM, the additive genetic variance could be altered simultaneously as a function of both DIM and THI values. This model could be recommended for the genetic evaluation taking into account the effect of G×E. The response to selection in the comfort zone (THI ≤ 66) is expected to be higher than that obtained in the heat stress zone (THI > 66) of the animals. The genetic correlations between milk yield in the comfort and heat stress zones were less than unity at opposite extremes of the environmental gradient. Thus, the best animals for milk yield in the comfort zone are not necessarily the best in the zone of heat stress and, therefore, G×E due to heat stress should not be neglected in the genetic evaluation.

Stress-opioid interactions: a comparison of morphine and methadone.

Science.gov (United States)

Taracha, Ewa; Mierzejewski, Paweł; Lehner, Małgorzata; Chrapusta, Stanisław J; Kała, Maria; Lechowicz, Wojciech; Hamed, Adam; Skórzewska, Anna; Kostowski, Wojciech; Płaźnik, Adam

2009-01-01

The utility of methadone and morphine for analgesia and of methadone for substitution therapy for heroin addiction is a consequence of these drugs acting as opioid receptor agonists.We compared the cataleptogenic and antinociceptive effects of single subcutaneous doses of methadone hydrochloride (1-4 mg/kg) and morphine sulfate (2.5-10 mg/kg) using catalepsy and hot-plate tests, and examined the effects of the highest doses of the drugs on Fos protein expression in selected brain regions in male Sprague-Dawley rats. Methadone had greater cataleptogenic and analgesic potency than morphine. Fos immunohistochemistry revealed substantial effects on the Fos response of both the stress induced by the experimental procedures and of the drug exposure itself. There were three response patterns identified: 1) drug exposure, but not stress, significantly elevated Fos-positive cell counts in the caudate-putamen; 2) stress alone and stress combined with drug exposure similarly elevated Fos-positive cell counts in the nucleus accumbens and cingulate cortex; and 3) methadone and morphine (to a lesser extent) counteracted the stimulatory effect of nonpharmacological stressors on Fos protein expression in the somatosensory cortex barrel field, and Fos-positive cell counts in this region correlated negatively with both the duration of catalepsy and the latency time in the hot-plate test. The overlap between brain regions reacting to nonpharmacological stressors and those responding to exogenous opioids suggests that stress contributes to opioid-induced neuronal activation.

Interactions of silica nanoparticles with therapeutics for oxidative stress attenuation in neurons

Science.gov (United States)

White-Schenk, Desiree; Shi, Riyi; Leary, James F.

2015-03-01

Oxidative stress plays a major role in many disease pathologies, notably in the central nervous system (CNS). For instance, after initial spinal cord injury, the injury site tends to increase during a secondary chemical injury process based on oxidative stress from necrotic cells and the inflammatory response. Prevention of this secondary chemical injury would represent a major advance in the treatment of people with spinal cord injuries. Few therapeutics are useful in combating such stress in the CNS due to side effects, low efficacy, or half-life. Mesoporous silica nanoparticles show promise for delivering therapeutics based on the formation of a porous network during synthesis. Ideally, they increase the circulation time of loaded therapeutics to increase the half-life while reducing overall concentrations to avoid side effects. The current study explored the use of silica nanoparticles for therapeutic delivery of anti-oxidants, in particular, the neutralization of acrolein which can lead to extensive tissue damage due to its ability to generate more and more copies of itself when it interacts with normal tissue. Both an FDA-approved therapeutic, hydralazine, and natural product, epigallocatechin gallate, were explored as antioxidants for acrolein with nanoparticles for increased efficacy and stability in neuronal cell cultures. Not only were the nanoparticles explored in neuronal cells, but also in a co-cultured in vitro model with microglial cells to study potential immune responses to near-infrared (NIRF)-labeled nanoparticles and uptake. Studies included nanoparticle toxicity, uptake, and therapeutic response using fluorescence-based techniques with both dormant and activated immune microglia co-cultured with neuronal cells.

Analysis of genetic and genotype X environment interaction effects for agronomic traits of rice (oryza sativa l.) in salt tolerance

International Nuclear Information System (INIS)

Zhou, H.K.; Hayat, Y.; Fang, L.J.; Guo, R.F.; He, J.M.; Xu, H.M.

2010-01-01

A diallel cross experiment of 4 rice (Oryza sativa L.) female and 6 male varieties was conducted to study the genetic effects and their interaction with salt-stress condition of 7 agronomic traits in normal and salt-stressed planting conditions. The panicle length (PL), effective number of panicles per plant (ENP), plumped number of grains per panicles (PNG), total number of grains per panicles (TNG), 1000-grain weight (W), seed setting ratio (SSR) and grain weight per plant (PGW), were investigated. A genetic model including additive effect, dominance effect and their interaction effects with environment (ADE) was employed for analysis of data. It was observed that significant (p<0.05) additive effects, dominance effects, additive X environment interaction effects and dominance X environment interaction effects exist for most of the agronomic traits of rice. In addition, significant (p<0.05) narrow sense heritabilities of ENP, PNG, TNG, W and PGW were found, indicating that the genetic performance of these traits are greatly affected by salt stress condition. A significant (p<0.05) negative correlations in the additive effects and additive X environment interaction effects detected between ENP and PNG suggesting that selection on increasing of ENP can reduce PNG. In addition, there exist a highly significant (p<0.01) positive dominance correlation among the dominance effects of the ENP, PNG and TNG, which shows that it is possible to breed salt-tolerant rice variety by coordinating large panicle and multi-panicle in utilization of heterosis. (author)

Brain aromatase and circulating corticosterone are rapidly regulated by combined acute stress and sexual interaction in a sex-specific manner.

Science.gov (United States)

Dickens, M J; Balthazart, J; Cornil, C A

2012-10-01

Neural production of 17β-oestradiol via aromatisation of testosterone may play a critical role in rapid, nongenomic regulation of physiological and behavioural processes. In brain nuclei implicated in the control of sexual behaviour, sexual or stressfull stimuli induce, respectively, a rapid inhibition or increase in preoptic aromatase activity (AA). In the present study, we tested quail that were either nonstressed or acutely stressed (15 min of restraint) immediately before sexual interaction (5 min) with stressed or nonstressed partners. We measured nuclei-specific AA changes, corresponding behavioural output, fertilisation rates and corticosterone (CORT) concentrations. In males, sexual interaction rapidly reversed stress-induced increases of AA in the medial preoptic nucleus (POM). This time scale (sexual stimuli on POM AA may actively preserve sexual behaviour despite stress exposure. We also found distinct sex differences in contextual physiological responses: males did not show any effect of partner status, whereas females responded to both their stress exposure and the male partner's stress exposure at the level of circulating CORT and AA. In addition, fertilisation rates and female CORT correlated with the male partner's exhibition of sexually aggressive behaviour, suggesting that female perception of the male can affect their physiology as much as direct stress. Overall, male reproduction appears relatively simple: sexual stimuli, irrespective of stress, drives major neural changes including rapid reversal of stress-induced changes of AA. By contrast, female reproduction appears more nuanced and context specific, with subjects responding physiologically and behaviourally to stress, the male partner's stress exposure, and female-directed male behaviour. © 2012 The Authors. Journal of Neuroendocrinology © 2012 British Society for Neuroendocrinology.

Studying the Physical Basis of Global Warming: Thermal Effects of the Interaction between Radiation and Matter and Greenhouse Effect

Science.gov (United States)

Besson, Ugo; De Ambrosis, Anna; Mascheretti, Paolo

2010-01-01

We present a teaching module dealing with the thermal effects of interaction between radiation and matter, the infrared emission of bodies and the greenhouse effect devoted to university level and teacher education. The module stresses the dependence of the optical properties of materials (transparency, absorptivity and emissivity) on radiation…

Differential Effects of Acute Stress on Anticipatory and Consummatory Phases of Reward Processing

Science.gov (United States)

Kumar, Poornima; Berghorst, Lisa H.; Nickerson, Lisa D.; Dutra, Sunny J.; Goer, Franziska; Greve, Douglas; Pizzagalli, Diego A.

2014-01-01

Anhedonia is one of the core symptoms of depression and has been linked to blunted responses to rewarding stimuli in striatal regions. Stress, a key vulnerability factor for depression, has been shown to induce anhedonic behavior, including reduced reward responsiveness in both animals and humans, but the brain processes associated with these effects remain largely unknown in humans. Emerging evidence suggests that stress has dissociable effects on distinct components of reward processing, as it has been found to potentiate motivation/‘wanting’ during the anticipatory phase but reduce reward responsiveness/‘liking’ during the consummatory phase. To examine the impact of stress on reward processing, we used a monetary incentive delay (MID) task and an acute stress manipulation (negative performance feedback) in conjunction with functional magnetic resonance imaging (fMRI). Fifteen healthy participants performed the MID task under no-stress and stress conditions. We hypothesized that stress would have dissociable effects on the anticipatory and consummatory phases in reward-related brain regions. Specifically, we expected reduced striatal responsiveness during reward consumption (mirroring patterns previously observed in clinical depression) and increased striatal activation during reward anticipation consistent with non-human findings. Supporting our hypotheses, significant Phase (Anticipation/Consumption) x Stress (Stress/No-stress) interactions emerged in the putamen, nucleus accumbens, caudate and amygdala. Post-hoc tests revealed that stress increased striatal and amygdalar activation during anticipation but decreased striatal activation during consumption. Importantly, stress-induced striatal blunting was similar to the profile observed in clinical depression under baseline (no-stress) conditions in prior studies. Given that stress is a pivotal vulnerability factor for depression, these results offer insight to better understand the etiology of this

The Buffer Effect of Therapy Dog Exposure on Stress Reactivity in Undergraduate Students.

Science.gov (United States)

Fiocco, Alexandra J; Hunse, Anastasia M

2017-06-30

Stress is an insidious health risk that is commonly reported among university students. While research suggests that dog exposure may facilitate recovery from a stress response, little is known about the buffer effect of dog exposure on the stress response to a future stressor. This study examined whether interaction with a therapy dog could reduce the strength of the physiological stress response when exposed to a subsequent stressor. Sixty-one university students were randomly assigned to either a therapy dog (TD, n = 31) or a no-dog control (C, n = 30) group. The stress response was measured by electrodermal activity (EDA) in response to the Paced Auditory Serial Addition Test (PASAT). Participants also completed questionnaires that assessed pet attitude, general stress levels, and affect. Analyses of covariance (ANCOVAs) showed that increase in EDA was significantly more pronounced in the C group than in the TD group ( p stress response in university students, which has implications for the promotion of a viable stress management program on university campuses.

Studying the physical basis of global warming: thermal effects of the interaction between radiation and matter and greenhouse effect

Energy Technology Data Exchange (ETDEWEB)

Besson, Ugo; De Ambrosis, Anna; Mascheretti, Paolo [Department of Physics ' A Volta' , University of Pavia, Via A Bassi 6, 27100 Pavia (Italy)], E-mail: ugo.besson@unipv.it, E-mail: anna.deambrosisvigna@unipv.it

2010-03-15

We present a teaching module dealing with the thermal effects of interaction between radiation and matter, the infrared emission of bodies and the greenhouse effect devoted to university level and teacher education. The module stresses the dependence of the optical properties of materials (transparency, absorptivity and emissivity) on radiation frequency, as a result of interaction between matter and radiation. Multiple experiences are suggested to favour a progressive construction of knowledge on the physical aspects necessary to understand the greenhouse effect and global warming. Some results obtained with university students are briefly reported.

Studying the physical basis of global warming: thermal effects of the interaction between radiation and matter and greenhouse effect

International Nuclear Information System (INIS)

Besson, Ugo; De Ambrosis, Anna; Mascheretti, Paolo

2010-01-01

We present a teaching module dealing with the thermal effects of interaction between radiation and matter, the infrared emission of bodies and the greenhouse effect devoted to university level and teacher education. The module stresses the dependence of the optical properties of materials (transparency, absorptivity and emissivity) on radiation frequency, as a result of interaction between matter and radiation. Multiple experiences are suggested to favour a progressive construction of knowledge on the physical aspects necessary to understand the greenhouse effect and global warming. Some results obtained with university students are briefly reported.

Contribution to the study of the interactions between residual stresses and oxygen dissolution in a reactive deformable solid

International Nuclear Information System (INIS)

Raceanu, Laura

2011-01-01

The aim of this PhD work is to highlight the interactions between the mechanical stress and the chemical composition within diffusion of matter process for a reactive solid. The chronological evolution of our work goes from a parametric numerical study to an experimental study and reveals the role of mechanical stresses on the oxygen diffusion process. Different origins of mechanical stress were first numerically analysed from the point of view of their impacts on the process of oxygen diffusion into a metal (Zr) or a ceramic (UO 2 ) subjected to an oxidizing environment. This approach allowed us: - to identify a surface treatment (shot-peening) able to generate a residual specific stress field, as a starting point for an experimental study implementation in order to validate the numerical study conclusions; - to highlight the ability of the stress field on the stabilisation of the morphology of an undulated metal/oxide interface (case of Zr). In the experimental approach, different techniques were used to characterize the material (GDOS, SEM, TGA, hole-drilling method, micro-hardness tests). They permitted the detection of a strong influence of shot-peening on the oxidation rate. The comparison of experimental and numerical simulation results reveals strong interactions between stress and compositions fields induced by the different treatments (shot-peening and/or pre-oxidation). This study opens up many opportunities in the understanding of multi-physics coupling effects being very useful for the optimization of mechanical and chemical surface-treatments, able furthermore to favour the diffusion (nitriding, cementation) or to slow it down (corrosion). (author) [fr

Effective interactions

International Nuclear Information System (INIS)

Elliott, J.P.

1981-01-01

This chapter attempts to describe and compare some of the more important nucleon-nucleon interactions that have been used in nuclear structure calculations, and to relate them where possible to the real nucleon-nucleon interaction. Explains that different interactions have been used depending on whether one is fitting to total binding energies and densities with a Hartree Fock (HF) calculation or fitting to spectra and spectroscopic data in a shell model calculation. Examines both types of calculation after two preliminary sections concerned with notation and with the philosophy underlying the use of model spaces and effective interactions. Discusses Skyrme interactions, finite range interactions, small model space, large model space, and the Sussex potential matrix elements. Focuses on the more empirical approaches in which a simple form is chosen for the effective interaction in a given model space and the parameters are deduced from fitting many-body data

Effects of harmane during treadmill exercise on spatial memory of restraint-stressed mice.

Science.gov (United States)

Nasehi, Mohammad; Shahini, Faezeh; Ebrahimi-Ghiri, Mohaddeseh; Azarbayjani, MohammadAli; Zarrindast, Mohammad-Reza

2018-06-08

Chronic stress induces hippocampal-dependent memory deficits, which can be counterbalanced with prolonged exercise. On the other hand, the β-carboline alkaloid harmane exerts potential in therapies for Alzheimer's and depression diseases and modulating neuronal responses to stress. The present study investigated the effect of chronic treatment of harmane alone or during treadmill running on spatial memory deficit in restraint-stressed mice. To examine spatial memory, adult male NMRI mice were subjected to the Y-maze. Intraperitoneal administration of harmane (0.6 mg/kg, once/ 48 h for 25 days) decreased the percentage of time in the novel arm and the number of novel arm visits, indicating a spatial memory deficit. A 9-day restraint stress (3 h/day) also produced spatial learning impairment. However, a 4-week regime of treadmill running (10 m/min for 30 min/day, 5 days/week) aggravated the stress impairing effect on spatial learning of 3-day stressed mice compared to exercise/non-stressed mice. Moreover, harmane (0.3 mg/kg) associated with exercise increased the number of novel arm visits in 9-day stressed mice compared to harmane/exercise/non-stressed or 9-day stressed group. It should be noted that none of these factors alone or in combination with each other had no effect on locomotor activity. Taken together, these data suggest that there is no interaction between harmane and exercise on spatial memory in stress condition. Copyright © 2018. Published by Elsevier Inc.

Stress and asthma

Directory of Open Access Journals (Sweden)

Shoji Nagata

1999-01-01

Full Text Available Three factors in recent medical research and treatment (advances in the field of psychoneuroimmunology, epidemiological evidence regarding important interaction between psychosocial factors and development of disease, and the recognition of the importance of patient education for self-management of asthma have led clinicians and researchers to reconsider the role of psychosocial stress in asthma. There are many reports suggesting that stressful life events, family problems and a behavior pattern that increases psychological conflict may influence the development or relapse of asthma and influence its clinical course. Depression is known as one of the risk factors of fatal asthmatic attack. In laboratory studies, about 20% of asthmatics were considered reactors who showed an airway change after exposure to emotional stress. Studies regarding the pathway of stress effect on allergy and asthma are reviewed and discussed from the standpoint of psychoneuroimmunology; for example, the enhancement of IgE production and increased susceptibility to respiratory infection by stress, conditioned anaphylaxis and nerve/mast cell interaction, the effect of stress on various bronchial responses and the inhibition of the immediate and late asthmatic response by anterior hypothalamic lesioning.

No interactions between genetic polymorphisms and stressful life events on outcome of antidepressant treatment

DEFF Research Database (Denmark)

Bukh, Jens Drachmann; Bock, Camilla; Vinberg, Maj

2009-01-01

Genetic polymorphisms seem to influence the response on antidepressant treatment and moderate the impact of stress on depression. The present study aimed to assess, whether allelic variants and stressful life events interact on the clinical outcome of depression. In a sample of 290 systematically...... recruited patients diagnosed with a single depressive episode according to ICD-10, we assessed the outcome of antidepressant treatment and the presence of stressful life events in a 6-month period preceding onset of depression by means of structured interviews. Further, we genotyped nine polymorphisms...... dependent on stressful life events experienced by the individual prior to onset of depression....

Effect of Temper Condition on Stress Relaxation Behavior of an Aluminum Copper Lithium Alloy

Science.gov (United States)

Mishra, Sumeet; Beura, Vikrant Kumar; Singh, Amit; Yadava, Manasij; Nayan, Niraj

2018-04-01

Deformation behavior of an Al-Cu-Li alloy in different temper conditions (solutionized and T8) is investigated using stress relaxation tests. Fundamental parameters such as the apparent and physical activation volume, strain rate sensitivity, effective stress, and exhaustion rate of mobile dislocation density are determined from single and multiple relaxation tests. It was found that dislocation-dislocation interaction controls the kinetics of plastic deformation in the solutionized sample, whereas dislocation-precipitate interaction is the overriding factor in the presence of T1 precipitates. The apparent activation volume was found to be significantly lower in the presence of T1 precipitates compared with solutionized samples. Strain rate sensitivity and effective stress were found to be higher in the presence of T1 precipitates. In addition, multiple relaxation tests showed that irrespective of microstructural features (solutes, semi-coherent precipitates), the mobile dislocation density reduces during the relaxation period. Further evidence regarding reduction in mobile dislocation density is obtained from uniaxial tensile tests carried out after stress relaxation tests, where both solutionized and T8 samples show an increase in strength. Additional discussion on relaxation strain is included to provide a complete overview regarding the time-dependent deformation behavior of the Al-Cu-Li alloy in different temper conditions.

Reynolds-Stress Budgets in an Impinging Shock Wave/Boundary-Layer Interaction

Science.gov (United States)

Vyas, Manan A.; Yoder, Dennis A.; Gaitonde, Datta V.

2018-01-01

Implicit large-eddy simulation (ILES) of a shock wave/boundary-layer interaction (SBLI) was performed. Comparisons with experimental data showed a sensitivity of the current prediction to the modeling of the sidewalls. This was found to be common among various computational studies in the literature where periodic boundary conditions were used in the spanwise direction, as was the case in the present work. Thus, although the experiment was quasi-two-dimensional, the present simulation was determined to be two-dimensional. Quantities present in the exact equation of the Reynolds-stress transport, i.e., production, molecular diffusion, turbulent transport, pressure diffusion, pressure strain, dissipation, and turbulent mass flux were calculated. Reynolds-stress budgets were compared with past large-eddy simulation and direct numerical simulation datasets in the undisturbed portion of the turbulent boundary layer to validate the current approach. The budgets in SBLI showed the growth in the production term for the primary normal stress and energy transfer mechanism was led by the pressure strain term in the secondary normal stresses. The pressure diffusion term, commonly assumed as negligible by turbulence model developers, was shown to be small but non-zero in the normal stress budgets, however it played a key role in the primary shear stress budget.

Blended Infant Massage–Parenting Enhancement Program on Recovering Substance-Abusing Mothers' Parenting Stress, Self-Esteem, Depression, Maternal Attachment, and Mother-Infant Interaction

Directory of Open Access Journals (Sweden)

Luz S. Porter, PhD, ARNP, FAANP, FAAN

2015-12-01

Conclusions: The findings suggest that infant massage blended into a structured parenting program has value-added effects in decreasing parenting stress and maternal depressive symptoms, but not on SAM's self-esteem, attachment, or maternal-infant interaction.

Combat Blast Injuries: Injury Severity and Posttraumatic Stress Disorder Interaction on Career Outcomes in Male Servicemembers

Science.gov (United States)

2013-01-01

post - traumatic stress disorder . INTRODUCTION Blasts are the most...Metzler TJ, Golding JM, Stewart A, Schlenger WE, Wells KB. Post - traumatic stress disorder and functioning and quality of life outcomes in a nationally...proportions were higher in those with posttraumatic stress disorder ( PTSD ) than in those without PTSD . There was a significant interaction between PTSD

Trans-generational effects of mild heat stress on the life history traits of an aphid parasitoid.

Science.gov (United States)

Ismaeil, Ibrahim; Doury, Géraldine; Desouhant, Emmanuel; Dubois, Françoise; Prevost, Geneviève; Couty, Aude

2013-01-01

Temperature changes are common in nature and insects are particularly exposed and sensitive to such variations which can be potential stresses, ultimately affecting life history traits and overall fitness. Braconids have been widely used to study the effects of temperature on host-parasitoid interactions and the present work focused on the solitary endoparasitoid Aphidius ervi Haliday (Hymenoptera: Braconidae Aphidiidae), an efficient biological control agent commercially used against aphids such as the potato aphid Macrosiphum euphorbiae Thomas (Sternorrhyncha: Aphididae). Contrary to previous studies using heat shocks at extreme temperatures, we evaluated the effects of mild heat stresses by transferring young parasitoid adults from the constant temperature of 20°C to either a warm (25°C) or hot (28°C) temperature, for either 1 h or 48 h. Such treatments are consistent with situations commonly experienced by parasitoids when moved from their rearing conditions to greenhouses or field conditions. The effects were evaluated both on the heat stressed A. ervi adults (G0) (immediate effects) and on their first generation (G1) progeny (trans-generational effects). G0 wasps' mortality was significantly affected by the temperature in interaction with the duration of the stress. Longevity of G0 wasps surviving the heat stress was negatively affected by the temperature and females lived longer than males. Heat stress applied to A. ervi parents also had consequences on their G1 progeny whose developmental time, rates of mummification and percentage of parasitoid completing total development were negatively affected. Surprisingly, the egg load at emergence of the G1 female progeny was increased when their mothers had been submitted to a mild heat stress of 25°C or 28°C. These results clearly demonstrate trans-generational phenotypic plasticity, showing that adaptation to thermal stresses may be achieved via maternal effects. This study also sheds light on the complexity

Trans-generational effects of mild heat stress on the life history traits of an aphid parasitoid.

Directory of Open Access Journals (Sweden)

Ibrahim Ismaeil

Full Text Available Temperature changes are common in nature and insects are particularly exposed and sensitive to such variations which can be potential stresses, ultimately affecting life history traits and overall fitness. Braconids have been widely used to study the effects of temperature on host-parasitoid interactions and the present work focused on the solitary endoparasitoid Aphidius ervi Haliday (Hymenoptera: Braconidae Aphidiidae, an efficient biological control agent commercially used against aphids such as the potato aphid Macrosiphum euphorbiae Thomas (Sternorrhyncha: Aphididae. Contrary to previous studies using heat shocks at extreme temperatures, we evaluated the effects of mild heat stresses by transferring young parasitoid adults from the constant temperature of 20°C to either a warm (25°C or hot (28°C temperature, for either 1 h or 48 h. Such treatments are consistent with situations commonly experienced by parasitoids when moved from their rearing conditions to greenhouses or field conditions. The effects were evaluated both on the heat stressed A. ervi adults (G0 (immediate effects and on their first generation (G1 progeny (trans-generational effects. G0 wasps' mortality was significantly affected by the temperature in interaction with the duration of the stress. Longevity of G0 wasps surviving the heat stress was negatively affected by the temperature and females lived longer than males. Heat stress applied to A. ervi parents also had consequences on their G1 progeny whose developmental time, rates of mummification and percentage of parasitoid completing total development were negatively affected. Surprisingly, the egg load at emergence of the G1 female progeny was increased when their mothers had been submitted to a mild heat stress of 25°C or 28°C. These results clearly demonstrate trans-generational phenotypic plasticity, showing that adaptation to thermal stresses may be achieved via maternal effects. This study also sheds light on

ALS mutant SOD1 interacts with G3BP1 and affects stress granule dynamics.

Science.gov (United States)

Gal, Jozsef; Kuang, Lisha; Barnett, Kelly R; Zhu, Brian Z; Shissler, Susannah C; Korotkov, Konstantin V; Hayward, Lawrence J; Kasarskis, Edward J; Zhu, Haining

2016-10-01

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease. Mutations in Cu/Zn superoxide dismutase (SOD1) are responsible for approximately 20 % of the familial ALS cases. ALS-causing SOD1 mutants display a gain-of-toxicity phenotype, but the nature of this toxicity is still not fully understood. The Ras GTPase-activating protein-binding protein G3BP1 plays a critical role in stress granule dynamics. Alterations in the dynamics of stress granules have been reported in several other forms of ALS unrelated to SOD1. To our surprise, the mutant G93A SOD1 transgenic mice exhibited pathological cytoplasmic inclusions that co-localized with G3BP1-positive granules in spinal cord motor neurons. The co-localization was also observed in fibroblast cells derived from familial ALS patient carrying SOD1 mutation L144F. Mutant SOD1, unlike wild-type SOD1, interacted with G3BP1 in an RNA-independent manner. Moreover, the interaction is specific for G3BP1 since mutant SOD1 showed little interaction with four other RNA-binding proteins implicated in ALS. The RNA-binding RRM domain of G3BP1 and two particular phenylalanine residues (F380 and F382) are critical for this interaction. Mutant SOD1 delayed the formation of G3BP1- and TIA1-positive stress granules in response to hyperosmolar shock and arsenite treatment in N2A cells. In summary, the aberrant mutant SOD1-G3BP1 interaction affects stress granule dynamics, suggesting a potential link between pathogenic SOD1 mutations and RNA metabolism alterations in ALS.

Effect of crack-microcracks interaction on energy release rates

Science.gov (United States)

Chudnovsky, A.; Wu, Shaofu

1990-01-01

The energy release rates associated with the main crack advancing into its surrounding damage zone, and the damage zone translation relative to the main crack, as well as the energy of interaction between the crack and the damage zone are analyzed. The displacement and stress fields for this crack-damage interaction problem are reconstructed by employing a semi-empirical stress analysis which involves experimental evaluation of the average microcrack density in the damage zone.

Stress coping style does not determine social status, but influences the consequences of social subordination stress

NARCIS (Netherlands)

Boersma, Gretha; Schmeltzer, Michael; Scott, Karen; Scheurink, Antonius; Tamashiro, Kelli; Sakai, Randall

2017-01-01

Chronic stress exposure may have negative consequences for health. One of the most common sources of chronic stress is stress associated with social interaction. In rodents, the effects of social stress can be studied in a naturalistic way using the visual burrow system (VBS). The way an individual

Managing Stress. Project Seed.

Science.gov (United States)

Muto, Donna; Wilk, Jan

One of eight papers from Project Seed, this paper describes a stress management project undertaken with high school sophomores. Managing Stress is described as an interactive workshop that offers young people an opportunity to examine specific areas of stress in their lives and to learn effective ways to deal with them. The program described…

Interhemispheric Interaction and ADHD, Depression, Anxiety, and Stress in Non-clinical Adults

NARCIS (Netherlands)

Mohamed, Saleh; Borger, Norbert; Geuze, Reint; van der Meere, Jacob

2014-01-01

Clinical studies indicate that ADHD, depression, anxiety and stress are related to impaired interhemispheric communication and anomalies in the right hemisphere functioning. The current study aimed to investigate whether interhemispheric interaction (IHI) is related to ADHD and mood disorders in a

The interactive role of eating regulation and stress in the prediction of weight-related outcomes among college students.

Science.gov (United States)

Arsiwalla, Dilbur D; Arnold, Amanda W; Teel, Karla P; Ulrich, Pamela V; Gropper, Sareen S

2018-02-01

The interactive role of eating regulation and perceived stress on weight-related outcomes was examined among 319 sophomore year college students (110 males and 209 females). Moderated regressions were used to examine interactions between stress and eating regulation on study outcomes including body mass index (BMI) and body fat. Eating regulation moderated associations between stress and BMI and body fat outcomes. Students reporting high perceived stress, high autonomous eating regulation, low controlled regulation, and low amotivation exhibited higher outcomes (BMI and body fat) than those with similar eating regulation but lower perceived stress. Students with lower autonomous eating regulation and higher controlled regulation had no differences in study outcomes across levels of stress. College students who regulate their eating behaviours for health reasons (specifically showing autonomous regulation) exhibit higher BMI and body fat when they report higher levels of perceived stress. Health promotion programs for college students need to target education efforts towards stress reduction and healthy eating behaviours. Copyright © 2017 John Wiley & Sons, Ltd.

Effects of computer-based stress management training on psychological well-being and work performance in japanese employees: a cluster randomized controlled trial.

Science.gov (United States)

Umanodan, Rino; Shimazu, Akihito; Minami, Masahide; Kawakami, Norito

2014-01-01

This study evaluated the effectiveness of a computer-based stress management training (SMT) program in improving employees' psychological well-being and work performance. A total of 12 work units (N=263) were randomly assigned to either an intervention group (8 work units, n=142) or to a wait-list control group (4 work units, n=121). All participants were requested to answer online questionnaires assessing psychological well-being as a primary outcome, and coping style, social support, and knowledge about stress management as secondary outcomes at baseline (T0), immediately after the intervention (T1), and 2 months after the intervention (T2). The group × time interaction was tested using a mixed-model repeated measures ANOVA. Results showed a group × time interaction for "knowledge about stress management" in the entire sample. Among participants who had more than 3 d of training, a significant group × time interaction was observed for "problem-solving" and "avoidance and suppression" as well as "knowledge about stress management." Our computer-based stress management program was effective for improving knowledge about stress management. It was also effective for improving coping skills in instances where participants had enough time (at least 3 d) to complete all sessions.

Effect of applied stress on the compressive residual stress introduced by laser peening

International Nuclear Information System (INIS)

Sumiya, Rie; Tazawa, Toshiyuki; Narazaki, Chihiro; Saito, Toshiyuki; Kishimoto, Kikuo

2016-01-01

Peening is the process which is able to be generated compressive residual stress and is known to be effective for preventing SCC initiation and improvement of fatigue strength. Laser peening is used for the nuclear power plant components in order to prevent SCC initiation. Although it is reported that the compressive residual stress decreases due to applied stresses under general operating condition, the change of residual stress might be large under excessive loading such as an earthquake. The objectives of this study are to evaluate the relaxation behavior of the compressive residual stress due to laser peening and to confirm the surface residual stress after loading. Therefore laser peened round bar test specimens of SUS316L which is used for the reactor internals of nuclear power plant were loaded at room temperature and elevated temperature and then surface residual stresses were measured by X-ray diffraction method. In the results of this test, it was confirmed that the compressive residual stress remained after applying uniform stress larger than 0.2% proof stress, and the effect of cyclic loading on the residual stress was small. The effect of applying compressive stress on the residual stress relaxation was confirmed to be less than that of applying tensile stress. Plastic deformation through a whole cross section causes the change in the residual stress distribution. As a result, the surface compressive residual stress is released. It was shown that the effect of specimen size on residual stress relaxation and the residual stress relaxation behavior in the stress concentration region can be explained by assumed stress relaxation mechanism. (author)

Stress-induced cognitive dysfunction: hormone-neurotransmitter interactions in the prefrontal cortex

Directory of Open Access Journals (Sweden)

Rebecca M Shansky

2013-04-01

Full Text Available The mechanisms and neural circuits that drive emotion and cognition are inextricably linked. Activation of the hypothalamic-pituitary-adrenal (HPA axis as a result of stress or other causes of arousal initiates a flood of hormone and neurotransmitter release throughout the brain, affecting the way we think, decide, and behave. This review will focus on factors that influence the function of the prefrontal cortex (PFC, a brain region that governs higher-level cognitive processes and executive function. The PFC becomes markedly impaired by stress, producing measurable deficits in working memory. These deficits arise from the interaction of multiple neuromodulators, including glucocorticoids, catecholamines, and gonadal hormones; here we will discuss the non- human primate and rodent literature that has furthered our understanding of the circuitry, receptors, and signaling cascades responsible for stress-induced prefrontal dysfunction.

Metabolic syndrome enhances endoplasmic reticulum, oxidative stress and leukocyte-endothelium interactions in PCOS.

Science.gov (United States)

Bañuls, Celia; Rovira-Llopis, Susana; Martinez de Marañon, Aranzazu; Veses, Silvia; Jover, Ana; Gomez, Marcelino; Rocha, Milagros; Hernandez-Mijares, Antonio; Victor, Victor M

2017-06-01

Polycystic ovary syndrome (PCOS) is associated with insulin resistance, which can lead to metabolic syndrome (MetS). Oxidative stress and leukocyte-endothelium interactions are related to PCOS. Our aim was to evaluate whether the presence of MetS in PCOS patients can influence endoplasmic reticulum (ER) and oxidative stress and leukocyte-endothelium interactions. This was a prospective controlled study conducted in an academic medical center. The study population consisted of 148 PCOS women (116 without/32 with MetS) and 112 control subjects (87 without / 25 with MetS). Metabolic parameters, reactive oxygen species (ROS) production, ER stress markers (GRP78, sXBP1, ATF6), leukocyte-endothelium interactions, adhesion molecules (VCAM-1, ICAM-1, E-Selectin), TNF-α and IL-6 were determined. Total ROS, inflammatory parameters and adhesion molecules were enhanced in the presence of MetS (pPCOS+MetS group showed higher levels of IL-6 and ICAM-1 than controls (pPCOS and PCOS+MetS groups vs their respective controls (pPCOS groups (pPCOS+MetS patients exhibited higher GRP78 and ATF6 levels than controls and PCOS patients without MetS (pPCOS women, HOMA-IR was positively correlated with ICAM-1 (r=0.501; pPCOS, all of which are related to vascular complications. Copyright © 2017 Elsevier Inc. All rights reserved.

Blended Infant Massage-Parenting Enhancement Program on Recovering Substance-Abusing Mothers' Parenting Stress, Self-Esteem, Depression, Maternal Attachment, and Mother-Infant Interaction.

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Porter, Luz S; Porter, Brian O; McCoy, Virginia; Bango-Sanchez, Vivian; Kissel, Bonnie; Williams, Marjorie; Nunnewar, Sachin

2015-12-01

This study aimed to determine whether a blended Infant Massage-Parenting Enhancement Program (IMPEP) improved maternal psychosocial health outcomes (parenting stress, depressive symptoms, self-esteem, maternal attachment) and maternal-infant interaction among substance-addicted mothers (SAMs) actively engaged in outpatient rehabilitation. Designed as a randomized, three-group controlled trial testing two levels of psychoeducational intervention (IMPEP vs. PEP) and a control group (standard care parenting resources), the study was conducted in two substance abuse centers in southeast Florida on a convenience sample of 138 recovering SAM-infant pairs. IMPEP or PEP classes were held weekly on Weeks 2-5, with data collected at baseline (Week 1), Week 6, and Week 12 via structured interviews, observation (Observation Checklist on Maternal-Infant Interaction), and self-administered questionnaires (Abidin Parenting Stress Index, Beck Depression Inventory, Rosenberg Self-Esteem Scale, Muller's Maternal Attachment Inventory), analyzed descriptively and inferentially using Kruskall-Wallis analysis of variance and post hoc Wilcoxon rank sum and Mann-Whitney U tests. Both IMPEP and PEP groups had significantly increased Parenting Stress Index scores (decreased parenting stress) and decreased Beck Depression Inventory scores (decreased depressive symptoms) compared to controls at Week 12, whereas there were no clinically meaningful differences among study groups in Rosenberg Self-Esteem Scale, Muller's Maternal Attachment Inventory, or Observation Checklist on Maternal-Infant Interaction scores. Only the IMPEP group showed significant improvements in both psychological and physical (waist-hip ratio) measures of parenting stress over time. The findings suggest that infant massage blended into a structured parenting program has value-added effects in decreasing parenting stress and maternal depressive symptoms, but not on SAM's self-esteem, attachment, or maternal

Effective stress coefficient for uniaxial strain condition

DEFF Research Database (Denmark)

Alam, M.M.; Fabricius, I.L.

2012-01-01

one dimensional rock mechanical deformation. We further investigated the effect of boundary condition on the stress dependency of effective stress coefficient and discussed its application in reservoir study. As stress field in the reservoirs are most unlikely to be hydrostatic, effective stress...... determined under uniaxial strain condition will be more relevant in reservoir studies. Copyright 2012 ARMA, American Rock Mechanics Association....

Salubrious effects of oxytocin on social stress-induced deficits

OpenAIRE

Smith, Adam S.; Wang, Zuoxin

2011-01-01

Social relationships are a fundamental aspect of life, affecting social, psychological, physiological, and behavioral functions. While social interactions can attenuate stress and promote health, disruption, confrontations, isolation, or neglect in the social environment can each be major stressors. Social stress can impair the basal function and stress-induced activation of the hypothalamic-pituitary-adrenal (HPA) axis, impairing function of multiple biological systems and posing a risk to m...

Evidence for carbon flux shortage and strong carbon/nitrogen interactions in pea nodules at early stages of water stress.

Science.gov (United States)

Gálvez, Loli; González, Esther M; Arrese-Igor, Cesar

2005-09-01

Symbiotic N2 fixation in legume nodules declines under a wide range of environmental stresses. A high correlation between N2 fixation decline and sucrose synthase (SS; EC 2.4.1.13) activity down-regulation has been reported, although it has still to be elucidated whether a causal relationship between SS activity down-regulation and N2 fixation decline can be established. In order to study the likely C/N interactions within nodules and the effects on N2 fixation, pea plants (Pisum sativum L. cv. Sugar snap) were subjected to progressive water stress by withholding irrigation. Under these conditions, nodule SS activity declined concomitantly with apparent nitrogenase activity. The levels of UDP-glucose, glucose-1-phosphate, glucose-6-phosphate, and fructose-6-phosphate decreased in water-stressed nodules compared with unstressed nodules. Drought also had a marked effect on nodule concentrations of malate, succinate, and alpha-ketoglutarate. Moreover, a general decline in nodule adenylate content was detected. NADP+-dependent isocitrate dehydrogenase (ICDH; EC 1.1.1.42) was the only enzyme whose activity increased as a result of water deficit, compensating for a possible C/N imbalance and/or supplying NADPH in circumstances that the pentose phosphate pathway was impaired, as suggested by the decline in glucose-6-phosphate dehydrogenase (G6PDH; EC 1.1.1.49) activity. The overall results show the occurrence of strong C/N interactions in nodules subjected to water stress and support a likely limitation of carbon flux that might be involved in the decline of N2 fixation under drought.

Interactive effects of N-acetylcysteine and antidepressants.

Science.gov (United States)

Costa-Campos, Luciane; Herrmann, Ana P; Pilz, Luísa K; Michels, Marcus; Noetzold, Guilherme; Elisabetsky, Elaine

2013-07-01

N-acetylcysteine (NAC), a glutathione precursor and glutamate modulator, has been shown to possess various clinically relevant psychopharmacological properties. Considering the role of glutamate and oxidative stress in depressive states, the poor effectiveness of antidepressant drugs (ADs) and the benefits of drug combination for treating depression, the aim of this study was to explore the possible benefit of NAC as an add on drug to treat major depression. For that matter we investigated the combination of subeffective and effective doses of NAC with subeffective and effective doses of several ADs in the mice tail suspension test. The key finding of this study is that a subeffective dose of NAC reduced the minimum effective doses of imipramine and escitalopram, but not those of desipramine and bupropion. Moreover, the same subeffective dose of NAC increased the minimum effective dose of fluoxetine in the same model. In view of the advantages associated with using the lowest effective dose of antidepressant, the results of this study suggest the potential of a clinically useful interaction of NAC with imipramine and escitalopram. Further studies are necessary to better characterize the molecular basis of such interactions, as well as to typify the particular drug combinations that would optimize NAC as an alternative for treating depression. Copyright © 2013 Elsevier Inc. All rights reserved.

Interactions between Temperament, Stress, and Immune Function in Cattle

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N. C. Burdick

2011-01-01

Full Text Available The detrimental effects caused by stressors encountered by animals during routine handling can pose economic problems for the livestock industry due to increased costs ultimately borne by the producer and the consumer. Stress adversely affects key physiological processes of the reproductive and immune systems. In recent years stress responsiveness has been associated with cattle behavior, specifically temperament. Cattle with more excitable temperaments, as measured by chute score, pen score, and exit velocity (flight speed, exhibit greater basal concentrations of glucocorticoids and catecholamines. Similar to stressed cattle, more temperamental cattle (i.e., cattle exhibiting greater exit velocity or pen and chute scores have poorer growth performance, carcass characteristics, and immune responses. Thus, understanding the interrelationship of stress and temperament can help in the development of selection and management practices that reduce the negative influence of temperament on growth and productivity of cattle. This paper discusses the relationship between stress and temperament and the developing evidence of an effect of temperament on immune function of cattle that have been handled or restrained. Specifically, the paper discusses different methodologies used to measure temperament, including chute score, pen score, and exit velocity, and discusses the reaction of cattle to different stressors including handling and restraint.

Water stress mitigates the negative effects of ozone on photosynthesis and biomass in poplar plants.

Science.gov (United States)

Gao, Feng; Catalayud, Vicent; Paoletti, Elena; Hoshika, Yasutomo; Feng, Zhaozhong

2017-11-01

Tropospheric ozone (O 3 ) pollution frequently overlaps with drought episodes but the combined effects are not yet understood. We investigated the physiological and biomass responses of an O 3 sensitive hybrid poplar clone ('546') under three O 3 levels (charcoal-filtered ambient air, non-filtered ambient air (NF), and NF plus 40 ppb) and two watering regimes (well-watered (WW) and reduced watering (RW), i.e. 40% irrigation) for one growing season. Water stress increased chlorophyll and carotenoid contents, protecting leaves from pigment degradation by O 3 . Impairment of photosynthesis by O 3 was also reduced by stomatal closure due to water stress, which preserved light-saturated CO 2 assimilation rate, and the maximum carboxylation efficiency. Water stress increased water use efficiency of the leaves while O 3 decreased it, showing significant interactions. Effects were more evident in older leaves than in younger leaves. Water stress reduced biomass production, but the negative effects of O 3 were less in RW than in WW for total biomass per plant. A stomatal O 3 flux-based dose-response relationship was parameterized considering water stress effects, which explained biomass losses much better than a concentration-based approach. The O 3 critical level of Phytotoxic Ozone Dose over a threshold of 7 nmol O 3 .m -2 .s -1 (POD 7 ) for a 4% biomass loss in this poplar clone under different water regimes was 4.1 mmol m -2 . Our results suggest that current O 3 levels in most parts of China threaten poplar growth and that interaction with water availability is a key factor for O 3 risk assessment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Attenuation of Microbial Stress Due to Nano-Ag and Nano-TiO2 Interactions under Dark Conditions.

Science.gov (United States)

Wilke, Carolyn M; Tong, Tiezheng; Gaillard, Jean-François; Gray, Kimberly A

2016-10-04

Engineered nanomaterials (ENMs) are incorporated into thousands of commercial products, and their release into environmental systems creates complex mixtures with unknown toxicological outcomes. To explore this scenario, we probe the chemical and toxicological interactions of nanosilver (n-Ag) and nanotitania (n-TiO 2 ) in Lake Michigan water, a natural aqueous medium, under dark conditions. We find that the presence of n-Ag induces a stress response in Escherichia coli, as indicated by a decrease in ATP production observed at low concentrations (in the μg L -1 range), with levels that are environmentally relevant. However, when n-Ag and n-TiO 2 are present together in a mixture, n-TiO 2 attenuates the toxicity of n-Ag at and below 20 μg L -1 by adsorbing Ag + (aq) . We observe, however, that toxic stress cannot be explained by dissolved silver concentrations alone and, therefore, must also depend on silver associated with the nanoscale fraction. Although the attenuating effect of n-TiO 2 on n-Ag's toxicity is limited, this study emphasizes the importance of probing the toxicity of ENM mixtures under environmental conditions to assess how chemical interactions between nanoparticles change the toxicological effects of single ENMs in unexpected ways.

Nonlinear dynamic analysis of framed structures including soil-structure interaction effects

International Nuclear Information System (INIS)

Mahmood, M.N.; Ahmed, S.Y.

2008-01-01

The role of oil-structure interaction on seismic behavior of reinforced concrete structures is investigated in this paper. A finite element approach has been adopted to model the interaction system that consists of the reinforced concrete plane frame, soil deposit and interface which represents the frictional between foundation of the structure and subsoil. The analysis is based on the elasto-plastic behavior of the frame members (beams and columns) that is defined by the ultimate axial force-bending moment interaction curve, while the cap model is adopted to govern the elasto-plastic behavior of the soil material. Mohr-Coulomb failure law is used to determine the initiation of slippage at the interface, while the separation is assumed to determine the initiation of slippage at the interface, while the separation is assumed to occur when the stresses at the interface becomes tension stresses. New-Mark's Predictor-Corrector algorithm is adopted for nonlinear dynamic analysis. The main aim of present work is to evaluate the sensitivity of structures to different behavior of the soil and interface layer when subjected to an earthquake excitation. Predicted results of the dynamic analysis of the interaction system indicate that the soil-structure interaction problem can have beneficial effects on the structural behavior when different soil models (elastic and elasto-plastic) and interface conditions (perfect bond and permitted slip)are considered. (author)

Learning and CRF-Induced Indecision during Escape and Submission in Rainbow Trout during Socially Aggressive Interactions in the Stress-Alternatives Model

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Tangi R. Summers

2017-09-01

Full Text Available Socially stressful environments induce a phenotypic dichotomy of coping measures for populations in response to a dominant aggressor and given a route of egress. This submission- (Stay or escape-oriented (Escape dichotomy represents individual decision-making under the stressful influence of hostile social environments. We utilized the Stress-Alternatives Model (SAM to explore behavioral factors which might predict behavioral phenotype in rainbow trout. The SAM is a compartmentalized tank, with smaller and larger trout separated by an opaque divider until social interaction, and another divider occluding a safety zone, accessible by way of an escape route only large enough for the smaller fish. We hypothesized that distinctive behavioral responses during the first social interaction would indicate a predisposition for one of the behavioral phenotypes in the subsequent interactions. Surprisingly, increased amount or intensity of aggression received had no significant effect on promoting escape in test fish. In fact, during the first day of interaction, fish that turned toward their larger opponent during attack eventually learned to escape. Escaping fish also learn to monitor the patrolling behavior of aggressors, and eventually escape primarily when they are not being observed. Escape per se, was also predicted in trout exhibiting increased movements directed toward the escape route. By contrast, fish that consistently remained in the tank with the aggressor (Stay showed significantly higher frequency of swimming in subordinate positions, at the top or the bottom of the water column, as well as sitting at the bottom. In addition, a corticotropin-releasing factor (CRF-induced behavior, snap-shake, was also displayed in untreated fish during aggressive social interaction, and blocked by a CRF1 receptor antagonist. Especially prevalent among the Stay phenotype, snap-shake indicates indecision regarding escape-related behaviors. Snap-shake was also

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.

Microbial mitigation-exacerbation continuum: a novel framework for microbiome effects on hosts in the face of stress.

Science.gov (United States)

David, Aaron S; Thapa-Magar, Khum B; Afkhami, Michelle E

2018-03-01

A key challenge to understanding microbiomes and their role in ecological processes is contextualizing their effects on host organisms, particularly when faced with environmental stress. One influential theory, the Stress Gradient Hypothesis, might predict that the frequency of positive interactions increases with stressful conditions such that microbial taxa would mitigate harmful effects on host performance. Yet, equally plausible is that microbial taxa could exacerbate these effects. Here, we introduce the Mitigation-Exacerbation Continuum as a novel framework to conceptualize microbial mediation of stress. We (1) use this continuum to quantify microbial mediation of stress for six plant species and (2) test the association between these continuum values and natural species' abundance. We factorially manipulated a common stress (allelopathy) and the presence of soil microbes to quantify microbial effects in benign and stressed environments for two critical early life-history metrics, seed germination and seedling biomass. Although we found evidence of both mitigation and exacerbation among the six species, exacerbation was more common. Across species, the degree of microbial-mediated effects on germination explained >80% of the variation of natural field abundances. Our results suggest a critical role of soil microbes in mediating plant stress responses, and a potential microbial mechanism underlying species abundance. © 2018 by the Ecological Society of America.

The Positive Effect of Resilience on Stress and Business Outcomes in Difficult Work Environments.

Science.gov (United States)

Shatté, Andrew; Perlman, Adam; Smith, Brad; Lynch, Wendy D

2017-02-01

To examine whether resilience has a protective effect in difficult work environments. A survey of 2063 individuals measured individual resilience, stress, burnout, sleep problems, likelihood of depression, job satisfaction, intent to quit, absences, and productivity. It also measured work characteristics: job demands, job influence, and social support. Multivariate and logistic regression models examined the main effects and interactions of resilience and job characteristics. High strain work environments (high demand, low influence, and low support) have an unfavorable effect on all outcomes. Resilience has a protective effect on all outcomes. For stress, burnout, and sleep, higher resilience has a more protective effect under low-strain conditions. For depression, absence and productivity, resilience has a more protective effect when job strain is high. Workers with high resilience have better outcomes in difficult work environments.

The Effect of Perceiving a Calling on Pakistani Nurses' Organizational Commitment, Organizational Citizenship Behavior, and Job Stress.

Science.gov (United States)

Afsar, Bilal; Shahjehan, Asad; Cheema, Sadia; Javed, Farheen

2018-03-01

People differ considerably in the way in which they express and experience their nursing careers. The positive effects associated with having a calling may differ substantially based on individuals' abilities to live out their callings. In a working world where many individuals have little to no choice in their type of employment and thus are unable to live out a calling even if they have one, the current study examined how perceiving a calling and living a calling interacted to predict organizational commitment, organizational citizenship behavior, and job stress with career commitment mediating the effect of the interactions on the three outcome variables. The purpose of the study is to investigate the mediating effect of career commitment between the relationships of calling and (a) nurses' attitudes (organizational commitment), (b) behaviors (organizational citizenship behavior), and (c) subjective experiences regarding work (job stress). Using a descriptive exploratory design, data were collected from 332 registered nurses working in Pakistani hospitals. Descriptive analysis and hierarchical regression analysis were used for data analysis. Living a calling moderated the effect of calling on career commitment, organizational citizenship behavior, and job stress, and career commitment fully mediated the effect of calling on organizational commitment, organizational citizenship behavior, and job stress. Increasing the understanding of calling, living a calling, and career commitment may increase nurses' organizational commitment and organizational citizenship behavior and decrease job stress. The study provided evidence to help nursing managers and health policy makers integrate knowledge and skills related to calling into career interventions and help nurses discover their calling.

Effects of Minority Stress, Group-Level Coping, and Social Support on Mental Health of German Gay Men.

Science.gov (United States)

Sattler, Frank A; Wagner, Ulrich; Christiansen, Hanna

2016-01-01

According to epidemiological studies, gay men are at a higher risk of mental disorders than heterosexual men. In the current study, the minority stress theory was investigated in German gay men: 1) it was hypothesized that minority stressors would positively predict mental health problems and that 2) group-level coping and social support variables would moderate these predictions negatively. Data from 1,188 German self-identified gay men were collected online. The questionnaire included items about socio-demographics, minority stress (victimization, rejection sensitivity, and internalized homonegativity), group-level coping (disclosure of sexual orientation, homopositivity, gay affirmation, gay rights support, and gay rights activism), and social support (gay social support and non-gay social support). A moderated multiple regression was conducted. Minority stressors positively predicted mental health problems. Group-level coping did not interact with minority stressors, with the exception of disclosure and homopositivity interacting marginally with some minority stressors. Further, only two interactions were found for social support variables and minority stress, one of them marginal. Gay and non-gay social support inversely predicted mental health problems. In addition, disclosure and homopositivity marginally predicted mental health problems. The findings imply that the minority stress theory should be modified. Disclosure does not have a relevant effect on mental health, while social support variables directly influence mental health of gay men. Group-level coping does not interact with minority stressors relevantly, and only one relevant interaction between social support and minority stress was found. Further longitudinal or experimental replication is needed before transferring the results to mental health interventions and prevention strategies for gay men.

Moderating effects of coping styles on anxiety and depressive symptoms caused by psychological stress in Chinese patients with Type 2 diabetes.

Science.gov (United States)

Zhang, C-X; Tse, L-A; Ye, X-Q; Lin, F-Y; Chen, Y-M; Chen, W-Q

2009-12-01

This study aimed to assess possible interactive effects of coping styles and psychological stress on depression and anxiety symptoms in Chinese patients with Type 2 diabetes. Three hundred and four patients with Type 2 diabetes underwent a face-to-face interview by trained research staff according to a standardized questionnaire including information on socio-demographic characteristics, psychological stress, coping styles and anxiety and depressive symptoms. The interactive effects of coping styles and psychological stress on depression and anxiety symptoms were assessed by hierarchical multiple regression analyses. There were significant associations of the four domains of psychological stress with anxiety and depressive symptoms, except for the relationship between 'reduced economic condition' and depressive symptoms. 'Negative coping style' significantly increased the level of both anxiety and depressive symptoms; whereas, 'active coping style' and 'avoidant coping style' decreased the risk of depressive symptoms. The interactions of 'negative coping style' with 'worrying about decline in body/physical function' and 'reduced economic condition' significantly increased the risk of anxiety and depressive symptoms, and the interaction of 'social/family crisis caused by the disease' with 'avoidance coping style' and 'worrying about decline in body/physical function' with 'active coping style' significantly decreased the risk of depressive symptoms. The results of this study suggest that certain coping styles might moderate the association of psychological stress with anxiety and depressive symptoms in Chinese patients with Type 2 diabetes.

Ordinary Social Interaction and the Main Effect Between Perceived Support and Affect.

Science.gov (United States)

Lakey, Brian; Vander Molen, Randy J; Fles, Elizabeth; Andrews, Justin

2016-10-01

Relational regulation theory hypothesizes that (a) the main effect between perceived support and mental health primarily reflects ordinary social interaction rather than conversations about stress and how to cope with it, and (b) the extent to which a provider regulates a recipient's mental health primarily reflects the recipient's personal taste (i.e., is relational), rather than the provider's objective supportiveness. In three round-robin studies, participants rated each other on supportiveness and the quality of ordinary social interaction, as well as their own affect when interacting with each other. Samples included marines about to deploy to Afghanistan (N = 100; 150 dyads), students sharing apartments (N = 64; 96 dyads), and strangers (N = 48; 72 dyads). Perceived support and ordinary social interaction were primarily relational, and most of perceived support's main effect on positive affect was redundant with ordinary social interaction. The main effect between perceived support and affect emerged among strangers after brief text conversations, and these links were partially verified by independent observers. Findings for negative affect were less consistent with theory. Ordinary social interaction appears to be able to explain much of the main effect between perceived support and positive affect. © 2015 Wiley Periodicals, Inc.

Interaction effects among multiple job demands: an examination of healthcare workers across different contexts.

Science.gov (United States)

Jimmieson, Nerina L; Tucker, Michelle K; Walsh, Alexandra J

2017-05-01

Simultaneous exposure to time, cognitive, and emotional demands is a feature of the work environment for healthcare workers, yet effects of these common stressors in combination are not well established. Survey data were collected from 125 hospital employees (Sample 1, Study 1), 93 ambulance service employees (Sample 2, Study 1), and 380 aged care/disability workers (Study 2). Hierarchical multiple regressions were conducted. In Sample 1, high cognitive demand exacerbated high emotional demand on psychological strain and job burnout, whereas the negative effect of high emotional demand was not present at low cognitive demand. In Sample 2, a similar pattern between emotional demand and time demand on stress-remedial intentions was observed. In Study 2, emotional demand × time demand and time demand × cognitive demand interactions again revealed that high levels of two demands were stress-exacerbating and low levels of one demand neutralized the other. A three-way interaction on job satisfaction showed the negative impact of emotional demand was exacerbated when both time and cognitive demands were high, creating a "triple disadvantage" of job demands. The results demonstrate that reducing some job demands helps attenuate the stressful effects of other job demands on different employee outcomes.

Influence of older primiparity on childbirth, parenting stress, and mother-child interaction.

Science.gov (United States)

Sonobe, Mami; Usui, Masami; Hiroi, Kayoko; Asai, Hiromi; Hiramatsu, Mayumi; Nekoda, Yasutoshi; Hirose, Taiko

2016-04-01

Delivery at 35 years and above has increased in Japan. While there is much research concerning obstetrical risk and delivery at advanced age, little research addresses child-rearing after birth. This study seeks to identify how older primiparas' characteristics of child-rearing, parenting stress, and mother-child interaction differ from those of younger mothers. Participants were primipara women aged 35 years and above and primiparas aged 20-29 years; all delivered in the hospital. Questionnaires were distributed during hospitalization after birth and during home visits at 3 months, 1 year, and 2 years post-partum. Mother-child interactions during home visits were assessed using the Nursing Child Assessment Teaching Scale (NCATS). The older group included 13 primiparas, and the control group included seven primiparas at the study's end. Some older primiparas used fertility treatment and cesarean section, but primiparas in their 20s used neither. There were no significant differences in terms of depression, psychological health, size of networks, and number of daytime or night-time feedings. Statistically significant differences were as follows. Older primiparas experienced more social isolation and overall stress, and their children exhibited greater hypersensitivity/lack of adaptability at 3 months. Older mothers were more likely to report little effort by their children to please them at 1 and 2 years after birth. Under observation, older primiparas received higher NCATS caregiver scores, but children of primiparas in their 20s received higher child scores. Mothers and child-care specialists should recognize that older primiparas interact more favorably with their children, but have more parenting stress. © 2016 Japan Academy of Nursing Science.

Effects of acute psychological stress on placebo and nocebo responses in a clinically relevant model of visceroception.

Science.gov (United States)

Roderigo, Till; Benson, Sven; Schöls, Margarita; Hetkamp, Madeleine; Schedlowski, Manfred; Enck, Paul; Elsenbruch, Sigrid

2017-08-01

There is evidence to suggest a role of emotions in placebo and nocebo effects, but whether acute psychological stress changes the magnitude of placebo or nocebo responses has not been tested. In a clinically relevant model of visceroception, we assessed effects of acute psychological stress on changes in urgency and pain in response to positive or negative treatment suggestions. In 120 healthy volunteers, perceived urge-to-defecate and pain in response to individually calibrated rectal distensions were measured with visual analogue scales during a BASELINE. Participants then underwent the Trier Social Stress Test (N = 60) or a simple cognitive task (control, N = 60) and were randomized to positive (placebo), negative (nocebo), or neutral treatment information regarding intravenous administration of saline. The series of distensions was repeated, and changes in visual analogue scales from BASELINE to TEST were compared between groups using analysis of covariance and planned post hoc tests. Treatment information emerged as a main factor (P effects for both urgency and pain. Effects for urgency were modulated by stress (interaction effect: P stressed groups. For pain, effects of stress emerged for nocebo responses, which were only evident in stressed groups (P = 0.009). This is the first experimental study supporting effects of acute psychological stress on placebo and nocebo responses in visceroception. Results call for mechanistic as well as patient studies to assess how psychological stress shapes patients' treatment expectations and thereby affects health outcomes.

Stress hormones receptors in the amygdala mediate the effects of stress on the consolidation, but not the retrieval, of a non aversive spatial task.

Directory of Open Access Journals (Sweden)

Amir Segev

Full Text Available This study examined the effects of the arousal level of the rat and exposure to a behavioral stressor on acquisition, consolidation and retrieval of a non-aversive hippocampal-dependent learning paradigm, the object location task. Learning was tested under two arousal conditions: no previous habituation to the experimental context (high novelty stress/arousal level or extensive prior habituation (reduced novelty stress/arousal level. Results indicated that in the habituated rats, exposure to an out-of-context stressor (i.e, elevated platform stress impaired consolidation and retrieval, but not acquisition, of the task. Non-habituated animals under both stressed and control conditions did not show retention of the task. In habituated rats, RU-486 (10 ng/side, a glucocorticoid receptor (GR antagonist, or propranolol (0.75 µg/side, a beta-adrenergic antagonist, injected into the basolateral amygdala (BLA, prevented the impairing effects of the stressor on consolidation, but not on retrieval. The CB1/CB2 receptor agonist WIN55,212-2 (WIN, 5 µg/side microinjected into the BLA did not prevent the effects of stress on either consolidation or retrieval. Taken together the results suggest that: (i GR and β-adrenergic receptors in the BLA mediate the impairing effects of stress on the consolidation, but not the retrieval, of a neutral, non-aversive hippocampal-dependent task, (ii the impairing effects of stress on hippocampal consolidation and retrieval are mediated by different neural mechanisms (i.e., different neurotransmitters or different brain areas, and (iii the effects of stress on memory depend on the interaction between several main factors such as the stage of memory processing under investigation, the animal's level of arousal and the nature of the task (neutral or aversive.

Stress hormones receptors in the amygdala mediate the effects of stress on the consolidation, but not the retrieval, of a non aversive spatial task.

Science.gov (United States)

Segev, Amir; Ramot, Assaf; Akirav, Irit

2012-01-01

This study examined the effects of the arousal level of the rat and exposure to a behavioral stressor on acquisition, consolidation and retrieval of a non-aversive hippocampal-dependent learning paradigm, the object location task. Learning was tested under two arousal conditions: no previous habituation to the experimental context (high novelty stress/arousal level) or extensive prior habituation (reduced novelty stress/arousal level). Results indicated that in the habituated rats, exposure to an out-of-context stressor (i.e, elevated platform stress) impaired consolidation and retrieval, but not acquisition, of the task. Non-habituated animals under both stressed and control conditions did not show retention of the task. In habituated rats, RU-486 (10 ng/side), a glucocorticoid receptor (GR) antagonist, or propranolol (0.75 µg/side), a beta-adrenergic antagonist, injected into the basolateral amygdala (BLA), prevented the impairing effects of the stressor on consolidation, but not on retrieval. The CB1/CB2 receptor agonist WIN55,212-2 (WIN, 5 µg/side) microinjected into the BLA did not prevent the effects of stress on either consolidation or retrieval. Taken together the results suggest that: (i) GR and β-adrenergic receptors in the BLA mediate the impairing effects of stress on the consolidation, but not the retrieval, of a neutral, non-aversive hippocampal-dependent task, (ii) the impairing effects of stress on hippocampal consolidation and retrieval are mediated by different neural mechanisms (i.e., different neurotransmitters or different brain areas), and (iii) the effects of stress on memory depend on the interaction between several main factors such as the stage of memory processing under investigation, the animal's level of arousal and the nature of the task (neutral or aversive).

Neuroepigenetics of stress.

Science.gov (United States)

Griffiths, B B; Hunter, R G

2014-09-05

Stress, a common if unpredictable life event, can have pronounced effects on physiology and behavior. Individuals show wide variation in stress susceptibility and resilience, which are only partially explained by variations in coding genes. Developmental programing of the hypothalamic-pituitary-adrenal stress axis provides part of the explanation for this variance. Epigenetic approaches have successfully helped fill the explanatory gaps between the influences of gene and environment on stress responsiveness, and differences in the sequelae of stress across individuals and generations. Stress and the stress axis interacts bi-directionally with epigenetic marks within the brain. It is now clear that exposure to stress, particularly in early life, has both acute and lasting effects on these marks. They in turn influence cognitive function and behavior, as well as the risk for suicide and psychiatric disorders across the lifespan and, in some cases, unto future generations. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

Sexually dimorphic effects of ancestral exposure to vinclozolin on stress reactivity in rats.

Science.gov (United States)

Gillette, Ross; Miller-Crews, Isaac; Nilsson, Eric E; Skinner, Michael K; Gore, Andrea C; Crews, David

2014-10-01

How an individual responds to the environment depends upon both personal life history as well as inherited genetic and epigenetic factors from ancestors. Using a 2-hit, 3 generations apart model, we tested how F3 descendants of rats given in utero exposure to the environmental endocrine-disrupting chemical (EDC) vinclozolin reacted to stress during adolescence in their own lives, focusing on sexually dimorphic phenotypic outcomes. In adulthood, male and female F3 vinclozolin- or vehicle-lineage rats, stressed or nonstressed, were behaviorally characterized on a battery of tests and then euthanized. Serum was used for hormone assays, and brains were used for quantitative PCR and transcriptome analyses. Results showed that the effects of ancestral exposure to vinclozolin converged with stress experienced during adolescence in a sexually dimorphic manner. Debilitating effects were seen at all levels of the phenotype, including physiology, behavior, brain metabolism, gene expression, and genome-wide transcriptome modifications in specific brain nuclei. Additionally, females were significantly more vulnerable than males to transgenerational effects of vinclozolin on anxiety but not sociality tests. This fundamental transformation occurs in a manner not predicted by the ancestral exposure or the proximate effects of stress during adolescence, an interaction we refer to as synchronicity.

Callous-unemotional traits and early life stress predict treatment effects on stress and sex hormone functioning in incarcerated male adolescents.

Science.gov (United States)

Johnson, Megan; Vitacco, Michael J; Shirtcliff, Elizabeth A

2018-03-01

The stress response system is highly plastic, and hormone rhythms may "adaptively calibrate" in response to treatment. This investigation assessed whether stress and sex hormone diurnal rhythms changed over the course of behavioral treatment, and whether callous-unemotional (CU) traits and history of early adversity affected treatment results on diurnal hormone functioning in a sample of 28 incarcerated adolescent males. It was hypothesized that the treatment would have beneficial effects, such that healthier diurnal rhythms would emerge post-treatment. Diurnal cortisol, testosterone, and dehydroepiandrosterone (DHEA) were sampled two weeks after admission to the correctional/treatment facility, and again approximately four months later. Positive treatment effects were detected for the whole sample, such that testosterone dampened across treatment. CU traits predicted a non-optimal hormone response to treatment, potentially indicating biological preparedness to respond to acts of social dominance and aggression. The interaction between CU traits and adversity predicted a promising and sensitized response to treatment including increased cortisol and a steeper testosterone drop across treatment. Results suggest that stress and sex hormones are highly receptive to treatment during this window of development.

The effects of stress on nuclear power plant operational decision making and training approaches to reduce stress effects

International Nuclear Information System (INIS)

Mumaw, R.J.

1994-08-01

Operational personnel may be exposed to significant levels of stress during unexpected changes in plant state an plant emergencies. The decision making that identifies operational actions, which is strongly determined by procedures, may be affected by stress, and performance may be impaired. ER report analyzes potential effects of stress in nuclear power plant (NPP) settings, especially in the context of severe accident management (SAM). First, potential sources of stress in the NPP setting are identified. This analysis is followed by a review of the ways in which stress is likely to affect performance, with an emphasis on performance of cognitive skills that are linked to operational decision making. Finally, potential training approaches for reducing or eliminating stress effects are identified. Several training approaches have the potential to eliminate or mitigate stress effects on cognitive skill performance. First, the use of simulated events for training can reduce the novelty and uncertainty that can lead to stress and performance impairments. Second, training to make cognitive processing more efficient and less reliant on attention and memory resources can offset the reductions in these resources that occur under stressful conditions. Third, training that targets crew communications skills can reduce the likelihood that communications will fail under stress

The effects of stress on nuclear power plant operational decision making and training approaches to reduce stress effects

Energy Technology Data Exchange (ETDEWEB)

Mumaw, R.J.

1994-08-01

Operational personnel may be exposed to significant levels of stress during unexpected changes in plant state an plant emergencies. The decision making that identifies operational actions, which is strongly determined by procedures, may be affected by stress, and performance may be impaired. ER report analyzes potential effects of stress in nuclear power plant (NPP) settings, especially in the context of severe accident management (SAM). First, potential sources of stress in the NPP setting are identified. This analysis is followed by a review of the ways in which stress is likely to affect performance, with an emphasis on performance of cognitive skills that are linked to operational decision making. Finally, potential training approaches for reducing or eliminating stress effects are identified. Several training approaches have the potential to eliminate or mitigate stress effects on cognitive skill performance. First, the use of simulated events for training can reduce the novelty and uncertainty that can lead to stress and performance impairments. Second, training to make cognitive processing more efficient and less reliant on attention and memory resources can offset the reductions in these resources that occur under stressful conditions. Third, training that targets crew communications skills can reduce the likelihood that communications will fail under stress.

Correcting systematic inflation in genetic association tests that consider interaction effects: application to a genome-wide association study of posttraumatic stress disorder.

Science.gov (United States)

Almli, Lynn M; Duncan, Richard; Feng, Hao; Ghosh, Debashis; Binder, Elisabeth B; Bradley, Bekh; Ressler, Kerry J; Conneely, Karen N; Epstein, Michael P

2014-12-01

Genetic association studies of psychiatric outcomes often consider interactions with environmental exposures and, in particular, apply tests that jointly consider gene and gene-environment interaction effects for analysis. Using a genome-wide association study (GWAS) of posttraumatic stress disorder (PTSD), we report that heteroscedasticity (defined as variability in outcome that differs by the value of the environmental exposure) can invalidate traditional joint tests of gene and gene-environment interaction. To identify the cause of bias in traditional joint tests of gene and gene-environment interaction in a PTSD GWAS and determine whether proposed robust joint tests are insensitive to this problem. The PTSD GWAS data set consisted of 3359 individuals (978 men and 2381 women) from the Grady Trauma Project (GTP), a cohort study from Atlanta, Georgia. The GTP performed genome-wide genotyping of participants and collected environmental exposures using the Childhood Trauma Questionnaire and Trauma Experiences Inventory. We performed joint interaction testing of the Beck Depression Inventory and modified PTSD Symptom Scale in the GTP GWAS. We assessed systematic bias in our interaction analyses using quantile-quantile plots and genome-wide inflation factors. Application of the traditional joint interaction test to the GTP GWAS yielded systematic inflation across different outcomes and environmental exposures (inflation-factor estimates ranging from 1.07 to 1.21), whereas application of the robust joint test to the same data set yielded no such inflation (inflation-factor estimates ranging from 1.01 to 1.02). Simulated data further revealed that the robust joint test is valid in different heteroscedasticity models, whereas the traditional joint test is invalid. The robust joint test also has power similar to the traditional joint test when heteroscedasticity is not an issue. We believe the robust joint test should be used in candidate-gene studies and GWASs of

Opposite Effects of Stress on Pain Modulation Depend on the Magnitude of Individual Stress Response.

Science.gov (United States)

Geva, Nirit; Defrin, Ruth

2018-04-01

The effect of acute stress on pain threshold and intolerance threshold are reported as producing either hypoalgesia or hyperalgesia. Yet, the contribution of individual stress reactivity in this respect has not been established. The aim was to test 2 pain modulation paradigms under acute stress manipulation, to our knowledge, for the first time, to study whether stress differentially affects pain modulation, and whether the effect is related to individual stress response. Participants were 31 healthy subjects. Conditioned pain modulation (CPM) and pain adaptation were measured before and after inducing an acute stress response using the Montreal Imaging Stress Task. Subjects' stress response was evaluated according to salivary cortisol, autonomic function, and perceived stress and anxiety. The Montreal Imaging Stress Task induced a validated stress response. On a group level, stress induced reduction in CPM magnitude and increase in pain adaptation compared with baseline. These responses correlated with stress reactivity. When the group was subdivided according to stress reactivity, only high stress responders exhibited reduced CPM whereas only low stress responders exhibited increased pain adaptation. The results suggest that acute stress may induce opposite effects on pain modulation, depending on individual stress reactivity magnitude, with an advantage to low stress responders. This study evaluated the effect of acute stress on pain modulation. Pain modulation under stress is affected by individual stress responsiveness; decreased CPM occurs in high stress responders whereas increased pain adaptation occurs in low stress responders. Identification of high stress responders may promote better pain management. Copyright © 2017 The American Pain Society. Published by Elsevier Inc. All rights reserved.

Effects of prenatal stress on anxiety- and depressive-like behaviors are sex-specific in prepubertal rats.

Science.gov (United States)

Iturra-Mena, Ann Mary; Arriagada-Solimano, Marcia; Luttecke-Anders, Ariane; Dagnino-Subiabre, Alexies

2018-05-17

The fetal brain is highly susceptible to stress in late pregnancy, with lifelong effects of stress on physiology and behavior. The aim of this study was to determine the physiological and behavioral effects of prenatal stress during the prepubertal period of female and male rats. We subjected pregnant Sprague-Dawley rats to a restraint stress protocol from gestational day 14 until 21, a critical period for fetal brain susceptibility to stress effects. Male and female offspring were subsequently assessed at postnatal day 24 for anxiety- and depressive-like behaviors, and spontaneous social interaction. We also assessed maternal behaviors and two stress markers: basal vs. acute-evoked stress levels of serum corticosterone and body weight gain. Prenatal stress did not affect the maternal behavior, while both female and male offspring had higher body weight gain. On the other hand, lower levels of corticosterone after acute stress stimulation as well as anxiety- and depressive-like behaviors were only evident in stressed males compared to control males. These results suggest that prenatal stress induced sex-specific effects on the hypothalamus-pituitary-adrenal (HPA) axis activity and on behavior during prepuberty. The HPA axis of prenatally stressed male rats was less active compared to control males, as well as they were more anxious and experienced depressive-like behaviors. Our results can be useful to study the neurobiological basis of childhood depression at a pre-clinical level. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Psychological stress-relieving effects of chewing - Relationship between masticatory function-related factors and stress-relieving effects.

Science.gov (United States)

Tasaka, Akinori; Kikuchi, Manaki; Nakanishi, Kousuke; Ueda, Takayuki; Yamashita, Shuichiro; Sakurai, Kaoru

2018-01-01

The objective of the present study was to investigate the relationship between masticatory function-related factors (masticatory performance, occlusal contact area, maximum bite force, number of chewing strokes, and muscle activity) and the stress-relieving effects of chewing. A total of 28 healthy male subjects were instructed to rest or chew for 10min after 30min of stress loading with arithmetic calculations. Their stress state was assessed by measuring salivary cortisol levels. Saliva was collected at three time points: before stress loading, immediately after stress loading, and 10min after stress loading. Compared to resting, chewing produced a significantly greater reduction in the rate of change in salivary cortisol levels 10min after stress loading. A negative correlation was observed between the rate of decrease in salivary cortisol levels and the number of chewing strokes. No significant correlation was observed between the rate of decrease in salivary cortisol levels and other measurement items. In healthy dentulous people, the number of chewing strokes has been shown to be a masticatory function-related factor that affects stress relief from chewing, suggesting the possibility that more appropriate chewing would produce a greater effect psychological stress relief. Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

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.

No effects of psychosocial stress on memory retrieval in non-treated young students with Generalized Social Phobia.

Science.gov (United States)

Espín, Laura; Marquina, Mónica; Hidalgo, Vanesa; Salvador, Alicia; Gómez-Amor, Jesús

2016-11-01

Generalized Social Phobia (GSP) is a common anxiety disorder that produces clear social life disruptions. There is no consensus on the specific processes involved in its development, but the role of the hypothalamic-pituitary-adrenal (HPA) axis has been suggested. This study analyzed the effects of the cortisol response to the Trier Social Stress Test (TSST) on the memory retrieval of pictures with different emotional valences in 45 non-treated young students with GSP and 50 non-anxious (NA) subjects (mean=19.35years, SD=0.18). No differences were found in the cortisol response of GSP and NA subjects to the TSST and control sessions. In addition, psychosocial stress impaired memory retrieval in both the GSP and NA groups, with no differences between them. Regarding the sex factor, no effects were found in the cortisol response to the TSST. However, during the encoding session, GSP men had higher cortisol levels than GSP women and NA subjects. There was also a significant interaction between sex and stress exposure on memory retrieval. Women recognized more unpleasant and neutral pictures than men; however, under stress, the women's advantage disappeared, and the men's performance improved. Sex also interacted with social phobia on positive mood, with GSP women exposed to the TSST showing the lowest positive mood. These results suggest that GSP subjects do not present an HPA axis sensitization to psychosocial stress, and they emphasize the importance of Sex in understanding stress effects on memory. Copyright © 2016 Elsevier Ltd. All rights reserved.

Prior exercise and antioxidant supplementation: effect on oxidative stress and muscle injury

Directory of Open Access Journals (Sweden)

Schilling Brian K

2007-10-01

Full Text Available Abstract Background Both acute bouts of prior exercise (preconditioning and antioxidant nutrients have been used in an attempt to attenuate muscle injury or oxidative stress in response to resistance exercise. However, most studies have focused on untrained participants rather than on athletes. The purpose of this work was to determine the independent and combined effects of antioxidant supplementation (vitamin C + mixed tocopherols/tocotrienols and prior eccentric exercise in attenuating markers of skeletal muscle injury and oxidative stress in resistance trained men. Methods Thirty-six men were randomly assigned to: no prior exercise + placebo; no prior exercise + antioxidant; prior exercise + placebo; prior exercise + antioxidant. Markers of muscle/cell injury (muscle performance, muscle soreness, C-reactive protein, and creatine kinase activity, as well as oxidative stress (blood protein carbonyls and peroxides, were measured before and through 48 hours of exercise recovery. Results No group by time interactions were noted for any variable (P > 0.05. Time main effects were noted for creatine kinase activity, muscle soreness, maximal isometric force and peak velocity (P Conclusion There appears to be no independent or combined effect of a prior bout of eccentric exercise or antioxidant supplementation as used here on markers of muscle injury in resistance trained men. Moreover, eccentric exercise as used in the present study results in minimal blood oxidative stress in resistance trained men. Hence, antioxidant supplementation for the purpose of minimizing blood oxidative stress in relation to eccentric exercise appears unnecessary in this population.

The effectiveness of cognitive behavioral stress management training on mental health, social interaction and family function in adolescents of families with one Human Immunodeficiency Virus (HIV positive member

Directory of Open Access Journals (Sweden)

Maryam Keypour

2011-01-01

Full Text Available Background: This study evaluated stress management training to improve mental health, social interaction and family function among adolescents of families with one Human Immunodeficiency Virus (HIV positive member. Methods: There were 34 adolescents (13-18 years old with at least one family member living with HIV from whom finally 15 attended the study and participated in 8 weekly sessions of stress management training. The tests used in this study were: Strengths and Difficulties Questionnaire (self and parent report, General Health Questionnare-28 (GHQ-28 and Family Assessment Device (FAD, conducted before, after and three months after the intervention. The collected data were analyzed by repeated measure test using SPSS software (Version 18.0. Results: Adolescents with one HIV positive family member showed high level of emotional problem (40% and conduct problem (33.3%. There was a significant difference between before, after and 3months after intervention based on GHQ-28 mean scores and FAD mean sores (p < 0.001. There was a significant difference between mean scores of peers′ relationship based on SDQ (self report and parents report forms before and after intervention, but there was no significant difference between mean scores of pro social behavior based on SDQ (self report and parents report forms in all three stages (before, after and three months after intervention. Conclusions: Stress management training is effective in improving mental health, family function and social interaction among adolescents living with parents infected with HIV/AIDS.

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....

The impact of early powered mobility on parental stress, negative emotions, and family social interactions.

Science.gov (United States)

Tefft, Donita; Guerette, Paula; Furumasu, Jan

2011-02-01

Powered mobility has been found to have positive effects on young children with severe physical disabilities, but the impact on the family has been less well documented. We evaluated the impact of early powered mobility on parental stress, negative emotions, perceived social interactions, and parental satisfaction with wheelchair characteristics such as size and durability. The participants were parents of 23 children with disabilities-10 with orthopedic disabilities (average age 30.1 months) and 13 with cerebral palsy (average age 47.0 months). Pretest assessments were completed two times: at initial wheelchair evaluation and at wheelchair delivery. A posttest assessment was completed after each child had used the wheelchair for 4-6 months. Parents reported a lower perceived level of stress at the time of wheelchair delivery, although the magnitude of this effect was fairly small, standardized mean difference (δ) = .27. They also reported an increased satisfaction with their child's social and play skills (δ = .38), ability to go where desired (δ = .86), sleep/wake pattern (δ = .61), and belief that the general public accepts their child (δ = .39) after several months using the wheelchair. Parents reported an increase in interactions within the family at the time of wheelchair delivery (δ = .66). There was no decrease in negative emotions. Parents were satisfied with most factors relating to the wheelchair itself, with areas of concern being wheelchair size and difficulty adjusting the wheelchair. The findings suggest that self-initiated powered mobility for a young child had a positive impact on the family.

Work stress, worries, and pain interact synergistically with modelled traffic noise on cross-sectional associations with self-reported sleep problems.

Science.gov (United States)

Kristiansen, Jesper; Persson, Roger; Björk, Jonas; Albin, Maria; Jakobsson, Kristina; Ostergren, Per-Olof; Ardö, Jonas

2011-02-01

To examine the risk of sleep problems associated with work stress (job strain, job demands, and decision authority), worries and pain and to investigate the synergistic interaction between these factors and traffic noise. Sleep problems and predictor variables were assessed in a cross-sectional public health survey with 12,093 respondents. Traffic noise levels were assessed using modelled A-weighted energy equivalent traffic sound levels at the residence. The risk of sleep problems was modelled using multiple logistic regression analysis. With regard to sleep problems not attributed to any external source (general sleep problems), independent main effects were found for traffic noise (women), decision authority (women), job strain, job demands, suffering from pain or other afflictions, worries about losing the job, experiencing bullying at work, having troubles paying the bills, and having a sick, disabled, or old relative to take care of (women). Significant synergistic effects were found for traffic noise and experiencing bullying at work in women. With regard to sleep problems attributed to traffic noise, strong synergistic interactions were found between traffic noise and, respectively, job demands (men), having pain or other afflictions, taking care of a sick, old, or disabled relative, and having troubles paying the bills. Main effects were found for worries about losing the job, experiencing bullying at work, job strain (men), and decision authority (men). Synergistic interactions could potentially contribute with 10-20% of the sleep problems attributed to traffic noise in the population. Work stress, pain, and different worries were independently associated with general sleep problems and showed in general no synergistic interaction with traffic noise. In contrast, synergistic effects between traffic noise and psychological factors were found with regard to sleep problems attributed to traffic noise. The synergy may contribute significantly to sleep

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.

Density dependent effective interactions

International Nuclear Information System (INIS)

Dortmans, P.J.; Amos, K.

1994-01-01

An effective nucleon-nucleon interaction is defined by an optimal fit to select on-and half-off-of-the-energy shell t-and g-matrices determined by solutions of the Lippmann-Schwinger and Brueckner-Bethe-Goldstone equations with the Paris nucleon-nucleon interaction as input. As such, it is seen to better reproduce the interaction on which it is based than other commonly used density dependent effective interactions. The new (medium modified) effective interaction when folded with appropriate density matrices, has been used to define proton- 12 C and proton- 16 O optical potentials. With them elastic scattering data are well fit and the medium effects identifiable. 23 refs., 8 figs

The ER stress sensor PERK luminal domain functions as a molecular chaperone to interact with misfolded proteins

Energy Technology Data Exchange (ETDEWEB)

Wang, Peng; Li, Jingzhi; Sha, Bingdong

2016-11-29

PERK is one of the major sensor proteins which can detect the protein-folding imbalance generated by endoplasmic reticulum (ER) stress. It remains unclear how the sensor protein PERK is activated by ER stress. It has been demonstrated that the PERK luminal domain can recognize and selectively interact with misfolded proteins but not native proteins. Moreover, the PERK luminal domain may function as a molecular chaperone to directly bind to and suppress the aggregation of a number of misfolded model proteins. The data strongly support the hypothesis that the PERK luminal domain can interact directly with misfolded proteins to induce ER stress signaling. To illustrate the mechanism by which the PERK luminal domain interacts with misfolded proteins, the crystal structure of the human PERK luminal domain was determined to 3.2 Å resolution. Two dimers of the PERK luminal domain constitute a tetramer in the asymmetric unit. Superimposition of the PERK luminal domain molecules indicated that the β-sandwich domain could adopt multiple conformations. It is hypothesized that the PERK luminal domain may utilize its flexible β-sandwich domain to recognize and interact with a broad range of misfolded proteins.

Quantum fields interacting with colliding plane waves: the stress-energy tensor and backreaction

International Nuclear Information System (INIS)

Dorca, M.; Verdaguer, E.

1997-01-01

Following a previous work on the quantization of a massless scalar field in a space-time representing the head on collision of two plane waves which focus into a Killing-Cauchy horizon, we compute the renormalized expectation value of the stress-energy tensor of the quantum field near that horizon in the physical state which corresponds to the Minkowski vacuum before the collision of the waves. It is found that for minimally coupled and conformally coupled scalar fields the respective stress-energy tensors are unbounded in the horizon. The specific form of the divergences suggests that when the semiclassical Einstein equations describing the backreaction of the quantum fields on the space-time geometry are taken into account, the horizon will acquire a curvature singularity. Thus the Killing-Cauchy horizon which is known to be unstable under ''generic'' classical perturbations is also unstable by vacuum polarization. The calculation is done following the point-splitting regularization technique. The dynamical colliding wave space-time has four quite distinct space-time regions, namely, one flat region, two single plane wave regions, and one interaction region. Exact mode solutions of the quantum field equation cannot be found exactly, but the blueshift suffered by the initial modes in the plane wave and interaction regions makes the use of the WKB expansion a suitable method of solution. To ensure the correct regularization of the stress-energy tensor, the initial flat modes propagated into the interaction region must be given to a rather high adiabatic order of approximation. (orig.)

Effects of Minority Stress, Group-Level Coping, and Social Support on Mental Health of German Gay Men.

Directory of Open Access Journals (Sweden)

Frank A Sattler

Full Text Available According to epidemiological studies, gay men are at a higher risk of mental disorders than heterosexual men. In the current study, the minority stress theory was investigated in German gay men: 1 it was hypothesized that minority stressors would positively predict mental health problems and that 2 group-level coping and social support variables would moderate these predictions negatively.Data from 1,188 German self-identified gay men were collected online. The questionnaire included items about socio-demographics, minority stress (victimization, rejection sensitivity, and internalized homonegativity, group-level coping (disclosure of sexual orientation, homopositivity, gay affirmation, gay rights support, and gay rights activism, and social support (gay social support and non-gay social support. A moderated multiple regression was conducted.Minority stressors positively predicted mental health problems. Group-level coping did not interact with minority stressors, with the exception of disclosure and homopositivity interacting marginally with some minority stressors. Further, only two interactions were found for social support variables and minority stress, one of them marginal. Gay and non-gay social support inversely predicted mental health problems. In addition, disclosure and homopositivity marginally predicted mental health problems.The findings imply that the minority stress theory should be modified. Disclosure does not have a relevant effect on mental health, while social support variables directly influence mental health of gay men. Group-level coping does not interact with minority stressors relevantly, and only one relevant interaction between social support and minority stress was found. Further longitudinal or experimental replication is needed before transferring the results to mental health interventions and prevention strategies for gay men.

The interaction between stress and exercise, and its impact on brain function.

Science.gov (United States)

Russell, Vivienne A; Zigmond, Michael J; Dimatelis, Jacqueline J; Daniels, William M U; Mabandla, Musa V

2014-06-01

In response to acute adversity, emotional signals shift the body into a state that permits rapid detection, identification, and appropriate response to a potential threat. The stress response involves the release of a variety of substances, including neurotransmitters, neurotrophic factors, hormones, and cytokines, that enable the body to deal with the challenges of daily life. The subsequent activation of various physiological systems can be both protective and damaging to the individual, depending on timing, intensity, and duration of the stressor. Successful recovery from stressful challenges during early life leads to strengthening of synaptic connections in health-promoting neural networks and reduced vulnerability to subsequent stressors that can be protective in later life. In contrast, chronic intense uncontrollable stress can be pathogenic and lead to disorders such as depression, anxiety, hypertension, Alzheimer's disease, Parkinson's disease, and an increased toxic response to additional stressors such as traumatic brain injury and stroke. This review briefly explores the interaction between stress experienced at different stages of development and exercise later in life.

Sleep quality but not sleep quantity effects on cortisol responses to acute psychosocial stress.

Science.gov (United States)

Bassett, Sarah M; Lupis, Sarah B; Gianferante, Danielle; Rohleder, Nicolas; Wolf, Jutta M

2015-01-01

Given the well-documented deleterious health effects, poor sleep has become a serious public health concern and increasing efforts are directed toward understanding underlying pathways. One potential mechanism may be stress and its biological correlates; however, studies investigating the effects of poor sleep on a body's capacity to deal with challenges are lacking. The current study thus aimed at testing the effects of sleep quality and quantity on cortisol responses to acute psychosocial stress. A total of 73 college-aged adults (44 females) were investigated. Self-reported sleep behavior was assessed via the Pittsburgh Sleep Quality Index and salivary cortisol responses to the Trier Social Stress Test were measured. In terms of sleep quality, we found a significant three-way interaction, such that relative to bad sleep quality, men who reported fairly good or very good sleep quality showed blunted or exaggerated cortisol responses, respectively, while women's stress responses were less dependent on their self-reported sleep quality. Contrarily, average sleep duration did not appear to impact cortisol stress responses. Lastly, participants who reported daytime dysfunctions (i.e. having trouble staying awake or keeping up enthusiasm) also showed a trend to blunted cortisol stress responses compared to participants who did not experience these types of daytime dysfunctions. Overall, the current study suggests gender-specific stress reactivity dysfunctions as one mechanism linking poor sleep with detrimental physical health outcomes. Furthermore, the observed differential sleep effects may indicate that while the body may be unable to maintain normal hypothalamic-pituitary-adrenal functioning in an acute psychosocial stress situation after falling prey to low sleep quality, it may retain capacities to deal with challenges during extended times of sleep deprivation.

Effects of Sex and Stress on Trigeminal Neuropathic Pain-Like Behavior in Rats.

Science.gov (United States)

Korczeniewska, Olga Anna; Khan, Junad; Tao, Yuanxiang; Eliav, Eli; Benoliel, Rafael

2017-01-01

To investigate the effects and interactions of sex and stress (provoked by chronic restraint [RS]) on pain-like behavior in a rat model of trigeminal neuropathic pain. The effects of sex and RS (carried out for 14 days as a model for stress) on somatosensory measures (reaction to pinprick, von Frey threshold) in a rat model of trigeminal neuropathic pain were examined. The study design was 2 × 4, with surgery (pain) and sham surgery (no pain) interacting with male restrained (RS) and unrestrained (nRS) rats and female RS and nRS rats. A total of 64 Sprague Dawley rats (32 males and 32 females) were used. Half of the animals in each sex group underwent RS, and the remaining half were left unstressed. Following the RS period, trigeminal neuropathic pain was induced by unilateral infraorbital nerve chronic constriction injury (IOCCI). Half of the animals in the RS group and half in the nRS group (both males and females) were exposed to IOCCI, and the remaining halves to sham surgery. Elevated plus maze (EPM) assessment and plasma interferon gamma (IFN-γ) levels were used to measure the effects of RS. Analysis of variance (ANOVA) was used to assess the effects of stress, sex, and their interactions on plasma IFN-γ levels, changes in body weight, EPM parameters, tactile allodynia, and mechanohyperalgesia. Pairwise comparisons were performed by using Tukey post hoc test corrected for multiple comparisons. Both male and female RS rats showed significantly altered exploratory behavior (as measured by EPM) and had significantly lower plasma IFN-γ levels than nRS rats. Rats exposed to RS gained weight significantly slower than the nRS rats, irrespective of sex. Following RS but before surgery, RS rats showed significant bilateral reductions in von Frey thresholds and significantly increased pinprick response difference scores compared to nRS rats, irrespective of sex. From 17 days postsurgery, RSIOCCI rats showed significantly reduced von Frey thresholds and

Kinematic Interaction and Rocking Effects on the Seismic Response of Viaducts on Pile Foundations

International Nuclear Information System (INIS)

Dezi, F.; Carbonari, S.; Leoni, G.

2008-01-01

This paper is aimed at providing a contribution for a more accurate and effective design of bridges founded on piles. A numerical model is employed herein to determine the stresses and displacements in the piles taking into account soil-foundation-structure interaction. A 3D finite element approach is developed for piles and superstructure whereas the soil is assumed to be a Winkler-type medium. The method is applied to single piers representative for a class of bridges. Varying the soil layers characteristics and the pile spacing (from 3 to 5 diameters), bending and axial stresses along piles as well as the pier base shear are computed. A comparison with respect to a fixed-base model is provided. Special issues such as the contribution of the soil profile, of the local amplification and of the rocking at the foundation level are discussed. Soil-structure interaction is found to be essential for effective design of bridges especially for squat piers and soft soil

Structural zooming research and development of an interactive computer graphical interface for stress analysis of cracks

Science.gov (United States)

Gerstle, Walter

1989-01-01

Engineering problems sometimes involve the numerical solution of boundary value problems over domains containing geometric feature with widely varying scales. Often, a detailed solution is required at one or more of these features. Small details in large structures may have profound effects upon global performance. Conversely, large-scale conditions may effect local performance. Many man-hours and CPU-hours are currently spent in modeling such problems. With the structural zooming technique, it is now possible to design an integrated program which allows the analyst to interactively focus upon a small region of interest, to modify the local geometry, and then to obtain highly accurate responses in that region which reflect both the properties of the overall structure and the local detail. A boundary integral equation analysis program, called BOAST, was recently developed for the stress analysis of cracks. This program can accurately analyze two-dimensional linear elastic fracture mechanics problems with far less computational effort than existing finite element codes. An interactive computer graphical interface to BOAST was written. The graphical interface would have several requirements: it would be menu-driven, with mouse input; all aspects of input would be entered graphically; the results of a BOAST analysis would be displayed pictorially but also the user would be able to probe interactively to get numerical values of displacement and stress at desired locations within the analysis domain; the entire procedure would be integrated into a single, easy to use package; and it would be written using calls to the graphic package called HOOPS. The program is nearing completion. All of the preprocessing features are working satisfactorily and were debugged. The postprocessing features are under development, and rudimentary postprocessing should be available by the end of the summer. The program was developed and run on a VAX workstation, and must be ported to the SUN

Regulatory interactions of stress and reward on rat forebrain opioidergic and GABAergic circuitry.

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Christiansen, A M; Herman, J P; Ulrich-Lai, Y M

2011-03-01

Palatable food intake reduces stress responses, suggesting that individuals may consume such ?comfort? food as self-medication for stress relief. The mechanism by which palatable foods provide stress relief is not known, but likely lies at the intersection of forebrain reward and stress regulatory circuits. Forebrain opioidergic and gamma-aminobutyric acid ergic signaling is critical for both reward and stress regulation, suggesting that these systems are prime candidates for mediating stress relief by palatable foods. Thus, the present study (1) determines how palatable ?comfort? food alters stress-induced changes in the mRNA expression of inhibitory neurotransmitters in reward and stress neurocircuitry and (2) identifies candidate brain regions that may underlie comfort food-mediated stress reduction. We used a model of palatable ?snacking? in combination with a model of chronic variable stress followed by in situ hybridization to determine forebrain levels of pro-opioid and glutamic acid decarboxylase (GAD) mRNA. The data identify regions within the extended amygdala, striatum, and hypothalamus as potential regions for mediating hypothalamic-pituitary-adrenal axis buffering following palatable snacking. Specifically, palatable snacking alone decreased pro-enkephalin-A (ENK) mRNA expression in the anterior bed nucleus of the stria terminalis (BST) and the nucleus accumbens, and decreased GAD65 mRNA in the posterior BST. Chronic stress alone increased ENK mRNA in the hypothalamus, nucleus accumbens, amygdala, and hippocampus; increased dynorphin mRNA in the nucleus accumbens; increased GAD65 mRNA in the anterior hypothalamus and BST; and decreased GAD65 mRNA in the dorsal hypothalamus. Importantly, palatable food intake prevented stress-induced gene expression changes in subregions of the hypothalamus, BST, and nucleus accumbens. Overall, these data suggest that complex interactions exist between brain reward and stress pathways and that palatable snacking can

Effects of autogenic training on stress response and heart rate variability in nursing students.

Science.gov (United States)

Lim, Seung-Joo; Kim, Chunmi

2014-12-01

This study was undertaken to confirm the effects of autogenic training (AT) on stress response and heart rate variability in nursing school students experiencing stress related to clinical training. The study was carried out from September 2012 to April 2013 in a quasi-experimental nonequivalent control group using a pretest-posttest design. The participants were 40 nursing students in their third year at either of two nursing colleges. All consented to participate. Nineteen nursing students at one college were assigned to the experimental group and underwent the 8-week AT program, and the other 21 were assigned to the control group and did not undergo any training. Stress response was assessed by questionnaire and HRV was measured three times, that is, before the program, at the end of the program, and 6 months after the end of the AT program. A significant time/group interaction was found for stress response (F = 4.68, p = .012), a subjective indicator. However, no significant interaction was found for the objective indicators of heart rate variability, normalized low frequency (F = 2.59, p = .090), normalized high frequency (F = 2.59, p = .090), or low frequency to high frequency ratio (F = 1.38, p = .257). The results suggest that AT provides an acceptable approach to stress reduction in nursing students. Copyright © 2014. Published by Elsevier B.V.

Effective stress law for anisotropic elastic deformation

International Nuclear Information System (INIS)

Carroll, M.M.

1979-01-01

An effective stress law is derived analytically to describe the effect of pore fluid pressure on the linearly elastic response of saturated porous rocks which exhibit anisotropy. For general anisotropy the difference between the effective stress and the applied stress is not hydrostatic. The effective stress law involves two constants for transversely isotropic response and three constants for orthotropic response; these constants can be expressed in terms of the moduli of the porous material and of the solid material. These expressions simplify considerably when the anisotropy is structural rather than intrinsic, i.e., in the case of an isotropic solid material with an anisotropic pore structure. In this case the effective stress law involves the solid or grain bulk modulus and two or three moduli of the porous material, for transverse isotropy and orthotropy, respectively. The law reduces, in the case of isotropic response, to that suggested by Geertsma (1957) and by Skempton (1961) and derived analytically by Nur and Byerlee

Effects of Mind-Body Training on Cytokines and Their Interactions with Catecholamines.

Science.gov (United States)

Jang, Joon Hwan; Park, Hye Yoon; Lee, Ui Soon; Lee, Kyung-Jun; Kang, Do-Hyung

2017-07-01

Mind-body training (MBT) may control reactions to stress and regulate the nervous and immune systems. The present study was designed to assess the effects of MBT on plasma cytokines and their interactions with catecholamines. The study group consisted of 80 subjects who practice MBT and a control group of 62 healthy subjects. Plasma catecholamine (norepinephrine, NE; epinephrine, E; and dopamine, DA) and cytokine (TNF-alpha, IL-6, IFN-gamma, and IL-10) levels were measured, and the differences between the MBT and control groups and the interactions of cytokines with catecholamines were investigated. A significant increase in IL-10+IFN-gamma was found in females of the MBT group compared with controls. Also, a significant increase of IL-10 (anti-inflammatory cytokine) in the MBT group was shown in a specific condition in which TNF-alpha and IL-6 (pro-inflammatory cytokines) are almost absent (≤1 ng/L) compared with controls. In the MBT group, significant positive correlations were found between IL-10 and the NE/E ratio and between IL-10 and the DA/E ratio, whereas the control group did not show any such correlations. MBT may increase IL-10, under specific conditions such as a decrease of pro-inflammatory cytokines or E, which may regulate the stress response and possibly contribute to effective and beneficial interactions between the nervous and immune systems.

Beneficial effects of CO2 enrichment to field-grown soybeans under ozone stress

International Nuclear Information System (INIS)

Lee, E.H.; Mulchi, C.L.

1991-01-01

Damage from gaseous air pollution [e.g. ozone (O 3 ) and sulfur dioxide (SO 2 )] on crops in the US has been estimated to exceed several billion dollars annually. Atmospheric carbon dioxide (CO 2 ) concentrations have increased from about 290 ppm in the late 1800's to current levels of 350 ppm. The combined effects of increased CO 2 and O 3 stress have not been studied under field conditions. The present study was conducted to determine the interactive effects of CO 2 enrichment and O 3 stress on the growth and physiology of 'Clark' soybean, testing the hypothesis that elevated CO 2 will ameliorate the effects of O 3 stress. Experiments with soybeans in open-top field chambers showed that increasing CO 2 levels to 400 parts per million (ppm) negated current ambient ozone harmful effects on soybean yields. When ambient O 3 levels were doubled, it was necessary to increase the atmospheric CO 2 concentration to 500 ppm to negate O 3 damage. Rising CO 2 counteracts O 3 pollution. Reduced stomatal conductance and decreased photosynthesis appear to reverse the CO 2 stimulation

Effects of early life stress on amygdala and striatal development

Science.gov (United States)

Fareri, Dominic S.; Tottenham, Nim

2016-01-01

Species-expected caregiving early in life is critical for the normative development and regulation of emotional behavior, the ability to effectively evaluate affective stimuli in the environment, and the ability to sustain social relationships. Severe psychosocial stressors early in life (early life stress; ELS) in the form of the absence of species expected caregiving (i.e., caregiver deprivation), can drastically impact one’s social and emotional success, leading to the onset of internalizing illness later in life. Development of the amygdala and striatum, two key regions supporting affective valuation and learning, is significantly affected by ELS, and their altered developmental trajectories have important implications for cognitive, behavioral and socioemotional development. However, an understanding of the impact of ELS on the development of functional interactions between these regions and subsequent behavioral effects is lacking. In this review, we highlight the roles of the amygdala and striatum in affective valuation and learning in maturity and across development. We discuss their function separately as well as their interaction. We highlight evidence across species characterizing how ELS induced changes in the development of the amygdala and striatum mediate subsequent behavioral changes associated with internalizing illness, positing a particular import of the effect of ELS on their interaction. PMID:27174149

Effects of early life stress on amygdala and striatal development.

Science.gov (United States)

Fareri, Dominic S; Tottenham, Nim

2016-06-01

Species-expected caregiving early in life is critical for the normative development and regulation of emotional behavior, the ability to effectively evaluate affective stimuli in the environment, and the ability to sustain social relationships. Severe psychosocial stressors early in life (early life stress; ELS) in the form of the absence of species expected caregiving (i.e., caregiver deprivation), can drastically impact one's social and emotional success, leading to the onset of internalizing illness later in life. Development of the amygdala and striatum, two key regions supporting affective valuation and learning, is significantly affected by ELS, and their altered developmental trajectories have important implications for cognitive, behavioral and socioemotional development. However, an understanding of the impact of ELS on the development of functional interactions between these regions and subsequent behavioral effects is lacking. In this review, we highlight the roles of the amygdala and striatum in affective valuation and learning in maturity and across development. We discuss their function separately as well as their interaction. We highlight evidence across species characterizing how ELS induced changes in the development of the amygdala and striatum mediate subsequent behavioral changes associated with internalizing illness, positing a particular import of the effect of ELS on their interaction. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Effects of early life stress on amygdala and striatal development

Directory of Open Access Journals (Sweden)

Dominic S. Fareri

2016-06-01

Full Text Available Species-expected caregiving early in life is critical for the normative development and regulation of emotional behavior, the ability to effectively evaluate affective stimuli in the environment, and the ability to sustain social relationships. Severe psychosocial stressors early in life (early life stress; ELS in the form of the absence of species expected caregiving (i.e., caregiver deprivation, can drastically impact one’s social and emotional success, leading to the onset of internalizing illness later in life. Development of the amygdala and striatum, two key regions supporting affective valuation and learning, is significantly affected by ELS, and their altered developmental trajectories have important implications for cognitive, behavioral and socioemotional development. However, an understanding of the impact of ELS on the development of functional interactions between these regions and subsequent behavioral effects is lacking. In this review, we highlight the roles of the amygdala and striatum in affective valuation and learning in maturity and across development. We discuss their function separately as well as their interaction. We highlight evidence across species characterizing how ELS induced changes in the development of the amygdala and striatum mediate subsequent behavioral changes associated with internalizing illness, positing a particular import of the effect of ELS on their interaction.

Prostaglandin E synthase interacts with inducible heat shock protein 70 after heat stress in bovine primary dermal fibroblast cells.

Science.gov (United States)

Richter, Constanze; Viergutz, Torsten; Schwerin, Manfred; Weitzel, Joachim M

2015-01-01

Exposure to heat stress in dairy cows leads to undesired side effects that are reflected by complex alterations in endocrine parameters, such as reduced progesterone, estradiol, and thyroid hormone concentrations. These endocrine maladaptation leads to failure to resume cyclicity, a poor uterine environment and inappropriate immune responses in postpartum dairy cows. Prostaglandins (PG's) are lipid mediators, which serve as signal molecules in response to various external stimuli as well as to cell-specific internal signal molecules. A central role in PG synthesis plays prostaglandin E synthase (PGES) that catalyzes the isomerization of PGH2 to PGE2 .The present study was conducted to investigate heat stress associated PGES expression. Expression of PGES and inducible heat shock protein 70 (HSP70), as a putative chaperonic protein, was studied in bovine primary fibroblasts under different heat shock conditions. Bovine primary fibroblasts produce PGE2 at homoiothermical norm temperature (38.5°C in bovine), but reduce PGE2 production rates under extreme heat stress (at 45°C for 6 h). By contrast, PGE2 production rates are maintained after a milder heat stress (at 41.5°C for 6 h). PGE2 synthesis is abolished by application of cyclooxygenase inhibitor indomethacin, indicating de novo synthesis. Heat stress increases HSP70 but not PGES protein concentrations. HSP70 physically interacts with PGES and the PGES-HSP70 complex did not dissociate upon heat stress at 45°C even after returning the cells to 37°C. The PGE2 production negatively correlates with the portion of PGES-HSP70 complex. These results suggest a protein interaction between HSP70 and PGES in dermal fibroblast cells. Blockage of PGES protein by HSP70 seems to interfere with the regulatory processes essential for cellular adaptive protection. © 2014 International Society for Advancement of Cytometry. © 2014 International Society for Advancement of Cytometry.

Inhibition of interaction between epigallocatechin-3-gallate and myofibrillar protein by cyclodextrin derivatives improves gel quality under oxidative stress.

Science.gov (United States)

Zhang, Yumeng; Chen, Lin; Lv, Yuanqi; Wang, Shuangxi; Suo, Zhiyao; Cheng, Xingguang; Xu, Xinglian; Zhou, Guanghong; Li, Zhixi; Feng, Xianchao

2018-06-01

High levels of polyphenols can interact with myofibrillar proteins (MPs), causing damage to a MP emulsion gel. In this study, β-cyclodextrins were used to reduce covalent and non-covalent interaction between epigallocatechin-3-gallate (EGCG) and MPs under oxidative stress. The loss of both thiol and free amine groups and the unfolding of MPs caused by EGCG (80 μM/g protein) were significantly prevented by β-cyclodextrins, and the structural stability and solubility were improved. MP emulsion gel treated with EGCG (80 μM/g protein) had the highest cooking loss (68.64%) and gel strength (0.51 N). Addition of β-cyclodextrins significantly reduced cooking loss (26.24-58.20%) and improved gel strength (0.31-0.41 N) of MP emulsion gel jeopardized by EGCG under oxidative stress. Damage to the emulsifying properties of MPs caused by EGCG was significantly prevented by addition of β-cyclodextrins. β-cyclodextrins reduced interaction between EGCG and MPs in the order Methyl-β-cyclodextrin > (2-Hydroxypropyl)-β-cyclodextrin > β-cyclodextrin. In absence of EGCG, addition of β-cyclodextrins partly protected MPs from oxidative attack and improved its solubility. It is concluded that β-cyclodextrins does not markedly reduce the antioxidant ability of EGCG according to carbonyl analysis, and can effectively increase EGCG loading to potentially provide more durable antioxidant effect for meat products during processing, transportation and storage. Copyright © 2018 Elsevier Ltd. All rights reserved.

PER1 rs3027172 genotype interacts with early life stress to predict problematic alcohol use, but not reward-related ventral striatum activity

Directory of Open Access Journals (Sweden)

David eBaranger

2016-03-01

Full Text Available Increasing evidence suggests that the circadian and stress regulatory systems contribute to alcohol use disorder (AUD risk, which may partially arise through effects on reward-related neural function. The C allele of the PER1 rs3027172 single nucleotide polymorphism reduces PER1 expression in cells incubated with cortisol and has been associated with increased risk for adult AUD and problematic drinking among adolescents exposed to high levels of familial psychosocial adversity. Using data from undergraduate students who completed the ongoing Duke Neurogenetics Study (n=665, we tested whether exposure to early life stress (ELS; Childhood Trauma Questionnaire moderates the association between rs3027172 genotype and later problematic alcohol use (Alcohol Use Disorders Identification Test as well as ventral striatum (VS reactivity to reward (card-guessing task while functional magnetic resonance imaging data were acquired. Initial analyses found that PER1 rs3027172 genotype interacted with ELS to predict both problematic drinking and VS reactivity; minor C allele carriers, who were also exposed to elevated ELS reported greater problematic drinking and exhibited greater ventral striatum reactivity to reward-related stimuli. When gene x covariate and environment x covariate interactions were controlled for, the interaction predicting problematic alcohol use remained significant (p<0.05, corrected while the interaction predicting VS reactivity was no longer significant. These results extend our understanding of relationships between PER1 genotype, early life stress, and problematic alcohol use, and serve as a cautionary tale on the importance of controlling for potential confounders in studies of moderation including gene x environment interactions.

New aspects of studies on stress response. Radiation-induced bystander effect

International Nuclear Information System (INIS)

Matsumoto, Hideki; Hayashi, Sachiko; Jin, Zhao-Hui; Hatashita, Masanori; Kano, Eiichi

2001-01-01

This review describes the bystander effect which is the secondary stress response induced by the primary target affected by radiation and other environmental factors. The bystander effect can be exerted from the primary target cells through the gap junction, through interaction between ligands and receptors, through interaction between secreted bystander factors and receptors and through secreted bystander factors. Through the first, the typical one firstly shown in AG1521 cells is that, despite the pass of only 2% of irradiated α-particles through the target cell nucleus, much more cells respond to express p53 and p21/WAF1. Through the second, the Fas/Fas ligand in the target induce apoptosis of the non-target cells. As for the third, participation of cytokines and growth factors is suggested. Many investigations concern the fourth of bystander effects by the bystander factors: e.g., authors have studied the effects of X-ray, carbon beam or hyperthermia on nitric oxide synthase induction in A-172 cells. Studies of bystander effects possibly extend the concept of radiation biology. (K.H.)

The role and effect of residual stress on pore generation during anodization of aluminium thin films

International Nuclear Information System (INIS)

Liao, M.W.; Chung, C.K.

2013-01-01

Highlights: •Al films of varying residual stress were prepared by sputtering. •Variation of the residual stress in the Al films influences pore growth during anodization. •The change in average pore size with residual stress is fairly small. •Interaction of residual stress with oxide growth stress leads to change in structure. •Residual tensile stress increases the pore density of porous alumina. -- Abstract: The role and effect of residual stress on pore generation of anodized aluminium oxide (AAO) have been investigated into anodizing the various-residual-stresses aluminium films. The plane stresses were characterised by X-ray diffraction with sin 2 ψ method. The pore density roughly linearly increased with residual stress from 64.6 (−132.5 MPa) to 90.5 pores/μm 2 (135.9 MPa). However, the average pore size around 40 nm was not changed significantly except for the rougher film. The tensile residual stress lessened the compressive oxide growth stress to reduce AAO plastic deformation for higher pore density. The findings provide new foundations for realizing AAO films on silicon

Resiliency to social defeat stress relates to the inter-strain social interaction and is influenced by season variation.

Science.gov (United States)

Han, Qiuqin; Yang, Liu; Liu, Yan; Lv, Ning; Yu, Jin; Wu, Gencheng; Zhang, Yuqiu

2014-02-21

Exposure to social defeat (SD) stress exerts social avoidance and depressive disorders. Little is known about the relationship between resiliency to stressors and the inter-strain social interaction (SI) level. We hypothesized that SD resiliency is correlated with a high SI between the same strain. C57BL/6J mice experienced a 10-day period of SD stress by repeated CD-1 mice offensive. The susceptible mice exhibited significant social-avoidance behaviors with less time in interaction-zone (IZ) and lower social interaction ratio (SIR) toward the Target (CD-1 mice), while resilient ones exhibited similar social interaction to control mice. When the Target was C57BL/6J mouse, either susceptible or resilient mice spent more time in IZ and the inter-strain SI in the resilient group was significantly higher than the susceptible. Correlation analysis revealed a significantly non-zero slope of the linear relationship between SIRs toward two strains. But different groups had a similar baseline of the inter-strain SI before stress, indicating a SD-induced defect in both types of SI. In addition, in four different seasons, animals exhibited a significant resiliency to the stress in summer. These data suggest that SD resiliency is related to a higher SI toward the same-strain, and may be regulated by seasonal variations. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Effect of temperature on the permeability of gas adsorbed coal under triaxial stress conditions

Science.gov (United States)

Li, Xiangchen; Yan, Xiaopeng; Kang, Yili

2018-04-01

The combined effects of gas sorption, stress and temperature play a significant role in the changing behavior of gas permeability in coal seams. The effect of temperature on nitrogen and methane permeability of naturally fractured coal is investigated. Coal permeability, P-wave velocity and axial strain were simultaneously measured under two effective stresses and six different temperatures. The results showed that the behavior of nitrogen and methane permeability presented nonmonotonic changes with increasing temperature. The variation in the P-wave velocity and axial strain showed a good correspondence with coal permeability. A higher effective stress limited the bigger deformation and caused the small change in permeability. Methane adsorption and desorption significantly influence the mechanical properties of coal and play an important role in the variations in coal permeability. The result of coal permeability during a complete stress-strain process showed that the variation in permeability is determined by the evolution of the internal structure. The increase in the temperature of the gas saturated coal causes the complex interaction between matrix swelling, matrix shrinkage and micro-fracture generation, which leads to the complex changes in coal structure and permeability. These results are helpful to understand the gas transport mechanism for exploiting coal methane by heat injection.

Social support and loneliness in college students: effects on pulse pressure reactivity to acute stress.

Science.gov (United States)

O'Donovan, Aoife; Hughes, Brian

2007-01-01

Socially supportive relationships at university may buffer against psychological stress in students, particularly in those experiencing loneliness. To examine the relation of social support at university and loneliness with pulse pressure (PP) reactivity to acute psychological stress in a sample of first-year undergraduate students. Sixty-five female, adolescent, first-year university students. Pulse pressure (PP) was calculated as the arithmetic difference between systolic blood pressure and diastolic blood pressure, which were measured during a resting baseline and during a stressful reading task. The difference between baseline and reading task PP represents PP reactivity. The Social Support at University Scale (SSUS) was used to assess social support availability in university, and the Revised UCLA Loneliness Scale was used to assess loneliness. Hierarchical linear regression was used to examine main and interactive effects of SSUS and loneliness on PP change scores, and simple slopes were computed to assist in the interpretation of interaction effects. Social support at university was associated with lower PP reactivity in students reporting medium (t = -2.03, p = .04) or high levels of loneliness (t = -2.93, p = .004), but not in those reporting low levels of loneliness (t = -0.20, p = .83). Psychosocial interventions designed to increase social support available at university, and targeted at students experiencing loneliness may buffer against the harmful effects of acute stressors in lonely first-year students.

Greater physiological and behavioral effects of interrupted stress pattern compared to daily restraint stress in rats.

Directory of Open Access Journals (Sweden)

Wei Zhang

Full Text Available Repeated stress can trigger a range of psychiatric disorders, including anxiety. The propensity to develop abnormal behaviors after repeated stress is related to the severity, frequency and number of stressors. However, the pattern of stress exposure may contribute to the impact of stress. In addition, the anxiogenic nature of repeated stress exposure can be moderated by the degree of coping that occurs, and can be reflected in homotypic habituation to the repeated stress. However, expectations are not clear when a pattern of stress presentation is utilized that diminishes habituation. The purpose of these experiments is to test whether interrupted stress exposure decreases homotypic habituation and leads to greater effects on anxiety-like behavior in adult male rats. We found that repeated interrupted restraint stress resulted in less overall homotypic habituation compared to repeated daily restraint stress. This was demonstrated by greater production of fecal boli and greater corticosterone response to restraint. Furthermore, interrupted restraint stress resulted in a lower body weight and greater adrenal gland weight than daily restraint stress, and greater anxiety-like behavior in the elevated plus maze. Control experiments demonstrated that these effects of the interrupted pattern could not be explained by differences in the total number of stress exposures, differences in the total number of days that the stress periods encompased, nor could it be explained as a result of only the stress exposures after an interruption from stress. These experiments demonstrate that the pattern of stress exposure is a significant determinant of the effects of repeated stress, and that interrupted stress exposure that decreases habituation can have larger effects than a greater number of daily stress exposures. Differences in the pattern of stress exposure are therefore an important factor to consider when predicting the severity of the effects of repeated

Modeling the Effects of Stress: An Approach to Training

Science.gov (United States)

Cuper, Taryn

2010-01-01

Stress is an integral element of the operational conditions experienced by combat medics. The effects of stress can compromise the performance of combat medics who must reach and treat their comrades under often threatening circumstances. Examples of these effects include tunnel vision, loss of motor control, and diminished hearing, which can result in an inability to perceive further danger, satisfactorily treat the casualty, and communicate with others. While many training programs strive to recreate this stress to aid in the experiential learning process, stress inducement may not always be feasible or desired. In addition, live simulations are not always a practical, convenient, and repeatable method of training. Instead, presenting situational training on a personal computer is proposed as an effective training platform in which the effects of stress can be addressed in a different way. We explore the cognitive and motor effects of stress, as well as the benefits of training for mitigating these effects in real life. While many training applications focus on inducing stress in order to "condition" the stress response, the author explores the possibilities of modeling stress to produce a similar effect. Can presenting modeled effects of stress help prepare or inoculate soldiers for stressful situations in which they must perform at a high level? This paper investigates feasibility of modeling stress and describes the preliminary design considerations of a combat medic training system that utilizes this method of battlefield preparation.

Stress effects on memory : An update and integration

NARCIS (Netherlands)

Schwabe, Lars; Joëls, Marian; Roozendaal, Benno; Wolf, Oliver T.; Oitzl, Melly S.

It is well known that stressful experiences may affect learning and memory processes. Less clear is the exact nature of these stress effects on memory: both enhancing and impairing effects have been reported. These opposite effects may be explained if the different time courses of stress hormone, in

Stress effects on memory: an update and integration

NARCIS (Netherlands)

Schwabe, L.; Joëls, M.; Roozendaal, B.; Wolf, O.T.; Oitzl, M.S.

2012-01-01

It is well known that stressful experiences may affect learning and memory processes. Less clear is the exact nature of these stress effects on memory: both enhancing and impairing effects have been reported. These opposite effects may be explained if the different time courses of stress hormone, in

Effects of osmotic stress on predation behaviour of Asterias rubens L.

NARCIS (Netherlands)

Aguera Garcia, Antonio; Schellekens, Tim; Jansen, J.M.; Smaal, A.C.

2015-01-01

Environmental stress plays an important role in determining ecosystem functioning and structure. In estuarine areas both tidal and seasonal salinity changes may cause osmotic stress on predators, affecting their behaviour and survival. The interaction between these predators and their prey may

Regulation of longevity by FGF21: Interaction between energy metabolism and stress responses.

Science.gov (United States)

Salminen, Antero; Kaarniranta, Kai; Kauppinen, Anu

2017-08-01

Fibroblast growth factor 21 (FGF21) is a hormone-like member of FGF family which controls metabolic multiorgan crosstalk enhancing energy expenditure through glucose and lipid metabolism. In addition, FGF21 acts as a stress hormone induced by endoplasmic reticulum stress and dysfunctions of mitochondria and autophagy in several tissues. FGF21 also controls stress responses and metabolism by modulating the functions of somatotropic axis and hypothalamic-pituitary-adrenal (HPA) pathway. FGF21 is a potent longevity factor coordinating interactions between energy metabolism and stress responses. Recent studies have revealed that FGF21 treatment can alleviate many age-related metabolic disorders, e.g. atherosclerosis, obesity, type 2 diabetes, and some cardiovascular diseases. In addition, transgenic mice overexpressing FGF21 have an extended lifespan. However, chronic metabolic and stress-related disorders involving inflammatory responses can provoke FGF21 resistance and thus disturb healthy aging process. First, we will describe the role of FGF21 in interorgan energy metabolism and explain how its functions as a stress hormone can improve healthspan. Next, we will examine both the induction of FGF21 expression via the integrated stress response and the molecular mechanism through which FGF21 enhances healthy aging. Finally, we postulate that FGF21 resistance, similarly to insulin resistance, jeopardizes human healthspan and accelerates the aging process. Copyright © 2017 Elsevier B.V. All rights reserved.

Mild effects of gestational stress and social reactivity on the onset of mother-young interactions and bonding in sheep.

Science.gov (United States)

Coulon, Marjorie; Lévy, Frédéric; Ravel, Christine; Nowak, Raymond; Boissy, Alain

2014-12-01

Consequences of prenatal stress on mother-young relationships are well-documented in altricial mammals but less so in precocial mammals. In this study, we investigated the effects of unpredictable aversive events on maternal behavior and mutual mother-young recognition in pregnant ewes while accounting for modulatory effects of ewe reactivity. From a population of 120 Romane-breed ewes, we selected 20 high-responsive (HR) and 20 low-responsive (LR) ewes according to pre-mating reactivity assessed in isolation tests. Over the final third of pregnancy, 10 HR ewes and 10 LR ewes were exposed daily to various aversive events such as social isolation, mixing and transport (stressed ewes), while the other 20 ewes were not exposed to aversive events (control ewes). Although the treatment induced chronic stress, physiologically confirmed by an increase in salivary cortisol following transport and sham shearing, maternal behavior of stressed ewes observed during the first 30 min postpartum and in the selectivity test 1 h 30 min later did not differ from controls. However, in a maternal motivation test performed 48 h postpartum, stressed ewes vocalized less than controls when separated from their lambs, and walked less readily past an unknown object to reach their lambs. Lambs of stressed ewes spent more time near their dam in a preference test performed 15 h after birth compared to control-ewe lambs. HR ewes spent more time grooming their lambs than LR ewes. We posit that domestication could have selected animals displaying robust expression of maternal behavior related to social reactivity and producing offspring that are better adapted to challenging situations.

Effects of salt stress on germination of some maize (Zea mays L ...

African Journals Online (AJOL)

STORAGESEVER

2009-10-05

Oct 5, 2009 ... Key words: Maize, NaCl, germination percentage, stress tolerance ındex, germination ındex. .... interactions between salt treatments and cultivars. This ..... Hormones and Abiotic Stresses on Germination, Growth and Phos-.

Stress effects on mood, HPA axis, and autonomic response: comparison of three psychosocial stress paradigms.

Directory of Open Access Journals (Sweden)

Grace E Giles

Full Text Available Extensive experimental psychology research has attempted to parse the complex relationship between psychosocial stress, mood, cognitive performance, and physiological changes. To do so, it is necessary to have effective, validated methods to experimentally induce psychosocial stress. The Trier Social Stress Test (TSST is the most commonly used method of experimentally inducing psychosocial stress, but it is resource intensive. Less resource intense psychosocial stress tasks include the Socially Evaluative Cold Pressor Task (SECPT and a computerized mental arithmetic task (MAT. These tasks effectively produce a physiological and psychological stress response and have the benefits of requiring fewer experimenters and affording data collection from multiple participants simultaneously. The objective of this study was to compare the magnitude and duration of these three experimental psychosocial stress induction paradigms. On each of four separate days, participants completed either a control non-stressful task or one of the three experimental stressors: the TSST, SECPT, or MAT. We measured mood, working memory performance, salivary cortisol and alpha-amylase (AA, and heart rate. The TSST and SECPT exerted the most robust effects on mood and physiological measures. TSST effects were generally evident immediately post-stress as well as 10- and 20-minutes after stress cessation, whereas SECPT effects were generally limited to the duration of the stressor. The stress duration is a key determinant when planning a study that utilizes an experimental stressor, as researchers may be interested in collecting dependent measures prior to stress cessation. In this way, the TSST would allow the investigator a longer window to administer tasks of interest.

Perinatal stress: characteristics and effects on adult eating behavior

Directory of Open Access Journals (Sweden)

Matilde Cesiana da Silva

2013-08-01

Full Text Available Many studies have pointed out the importance of mother-child interaction in the early months of life. A few decades ago, a method called kangaroo care was developed and its main goal was to keep underweight or premature newborns in direct contact with the mother. This method has reduced the morbidity and mortality of these newborns, increasing their growth rate, breastfeeding time and mother-child contact. In rodents, the dam's presence is crucial for avoiding aggression factors that may trigger phenotypic adaptations in the pups with irreversible morphological, functional and behavioral consequences. Eating behavior is an adaptive response stemming from the external environment demand and modulated by opportunities and limitations imposed by the external environment. This behavior is regulated by a complex interaction of peripheral and central mechanisms that control hunger and satiety. The hypothalamus is a brain structure that integrates central and peripheral signals to regulate energy homeostasis and body weight. The hypothalamic nucleus have orexigenic peptides, such as neuropeptide Y and the Agouti-related peptide, and anorexigenic peptides, such as cocaine and amphetamine regulated transcript and proopiomelanocortin. An innovative study of eating behavior in experimental models of neonatal stress separates the mother from the offspring during lactation. This review describes the effects of stress during the neonatal period on general physiological factors, particularly on the control of eating behavior.

Ecological interactions affecting population-level responses to chemical stress in Mesocyclops leuckarti.

Science.gov (United States)

Kulkarni, Devdutt; Hommen, Udo; Schäffer, Andreas; Preuss, Thomas G

2014-10-01

Higher tiers of ecological risk assessment (ERA) consider population and community-level endpoints. At the population level, the phenomenon of density dependence is one of the most important ecological processes that influence population dynamics. In this study, we investigated how different mechanisms of density dependence would influence population-level ERA of the cyclopoid copepod Mesocyclops leuckarti under toxicant exposure. We used a combined approach of laboratory experiments and individual-based modelling. An individual-based model was developed for M. leuckarti to simulate population dynamics under triphenyltin exposure based on individual-level ecological and toxicological data from laboratory experiments. The study primarily aimed to-(1) determine which life-cycle processes, based on feeding strategies, are most significant in determining density dependence (2) explore how these mechanisms of density dependence affect extrapolation from individual-level effects to the population level under toxicant exposure. Model simulations showed that cannibalism of nauplii that were already stressed by TPT exposure contributed to synergistic effects of biotic and abiotic factors and led to a twofold stress being exerted on the nauplii, thereby resulting in a higher population vulnerability compared to the scenario without cannibalism. Our results suggest that in population-level risk assessment, it is easy to underestimate toxicity unless underlying ecological interactions including mechanisms of population-level density regulation are considered. This study is an example of how a combined approach of experiments and mechanistic modelling can lead to a thorough understanding of ecological processes in ecotoxicology and enable a more realistic ERA. Copyright © 2014 Elsevier Ltd. All rights reserved.

The effect of stress on men's food selection.

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Zellner, Debra A; Saito, Shin; Gonzalez, Johanie

2007-11-01

This study investigates the effect of stress on food choice among men. Two groups of men were given either solvable (no-stress) or unsolvable (stress) anagrams to solve. Four bowls of snack foods-two healthy (peanuts and grapes) and two unhealthy (potato chips and M&M chocolate candies)-were available and subjects were invited to snack on them. Men in the no-stress group ate significantly more of the unhealthy foods than did men in the stress group. This finding is quite different from that found with women [Zellner et al. (2006). Food selection changes under stress. Physiology & Behavior, 87, 789-793]. Women tended to eat more grapes when not stressed than when stressed and more M&Ms when stressed than when not stressed. Thus, the effect of stress level on food choice is different for men and women.

Nicotine, adolescence, and stress: A review of how stress can modulate the negative consequences of adolescent nicotine abuse.

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Holliday, Erica; Gould, Thomas J

2016-06-01

In order to continue the decline of smoking prevalence, it is imperative to identify factors that contribute to the development of nicotine and tobacco addiction, such as adolescent initiation of nicotine use, adolescent stress, and their interaction. This review highlights the biological differences between adolescent and adults in nicotine use and resulting effects, and examines the enduring consequences of adolescent nicotine administration. A review of both clinical and preclinical literature indicates that adolescent, but not adult, nicotine administration leads to increased susceptibility for development of long-lasting impairments in learning and affect. Finally, the role stress plays in normal adolescent development, the deleterious effects stress has on learning and memory, and the negative consequences resulting from the interaction of stress and nicotine during adolescence is reviewed. The review concludes with ways in which future policies could benefit by addressing adolescent stress as a means of reducing adolescent nicotine abuse. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sibling Socialization: The Effects of Stressful Life Events and Experiences

Science.gov (United States)

Conger, Katherine J.; Stocker, Clare; McGuire, Shirley

2009-01-01

Stressful life events and experiences may disrupt the typical day-to-day interactions between sisters and brothers that provide the foundation of sibling socialization. This chapter examines four experiences that may affect patterns of sibling interaction: parental marital conflict, parental divorce and remarriage, foster care placement, and a…

Stress, strain, and structural dynamics an interactive handbook of formulas, solutions, and Matlab toolboxes

CERN Document Server

Yang, Bingen

2005-01-01

Stress, Strain, and Structural Dynamics is a comprehensive and definitive reference to statics and dynamics of solids and structures, including mechanics of materials, structural mechanics, elasticity, rigid-body dynamics, vibrations, structural dynamics, and structural controls. This text integrates the development of fundamental theories, formulas and mathematical models with user-friendly interactive computer programs, written in the powerful and popular MATLAB. This unique merger of technical referencing and interactive computing allows instant solution of a variety of engineering problems

Stress and subsidy effects of seagrass wrack duration, frequency, and magnitude on salt marsh community structure.

Science.gov (United States)

Hanley, Torrance C; Kimbro, David L; Hughes, Anne Randall

2017-07-01

Environmental perturbations can strongly affect community processes and ecosystem functions by acting primarily as a subsidy that increases productivity, a stress that decreases productivity, or both, with the predominant effect potentially shifting from subsidy to stress as the overall intensity of the perturbation increases. While perturbations are often considered along a single axis of intensity, they consist of multiple components (e.g., magnitude, frequency, and duration) that may not have equivalent stress and/or subsidy effects. Thus, different combinations of perturbation components may elicit community and ecosystem responses that differ in strength and/or direction (i.e., stress or subsidy) even if they reflect a similar overall perturbation intensity. To assess the independent and interactive effects of perturbation components, we experimentally manipulated the magnitude, frequency, and duration of wrack deposition, a common stress-subsidy in a variety of coastal systems. The effects of wrack perturbation on salt marsh community and ecosystem properties were assessed both in the short-term (at the end of a 12-week experimental manipulation) and long-term (6 months after the end of the experiment). In the short-term, plants and associated benthic invertebrates exhibited primarily stress-based responses to wrack perturbation. The extent of these stress effects on density of the dominant plant Spartina alterniflora, total plant percent cover, invertebrate abundance, and sediment oxygen availability were largely determined by perturbation duration. Yet, higher nitrogen content of Spartina, which indicates a subsidy effect of wrack, was influenced primarily by perturbation magnitude in the short-term. In the longer term, perturbation magnitude determined the extent of both stress and subsidy effects of wrack perturbation, with lower subordinate plant percent cover and snail density, and higher Spartina nitrogen content in high wrack biomass treatments

Final State Interactions Effects in Neutrino-Nucleus Interactions

Energy Technology Data Exchange (ETDEWEB)

Golan, Tomasz [Univ. of Wroctaw (Poland); Juszczak, Cezary [Univ. of Wroctaw (Poland); Sobczyk, Jan T. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)

2012-07-01

Final State Interactions effects are discussed in the context of Monte Carlo simulations of neutrino-nucleus interactions. A role of Formation Time is explained and several models describing this effect are compared. Various observables which are sensitive to FSI effects are reviewed including pion-nucleus interaction and hadron yields in backward hemisphere. NuWro Monte Carlo neutrino event generator is described and its ability to understand neutral current $\\pi^0$ production data in $\\sim 1$ GeV neutrino flux experiments is demonstrated.

Effects of Early-Life Stress on Social and Anxiety-Like Behaviors in Adult Mice: Sex-Specific Effects

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Natalya P. Bondar

2018-01-01

Full Text Available Stressful events in an early postnatal period have critical implications for the individual’s life and can increase later risk for psychiatric disorders. The aim of this study was to investigate the influence of early-life stress on the social behavior of adult male and female mice. C57Bl/6 mice were exposed to maternal separation (MS, 3 h once a day or handling (HD, 15 min once a day on postnatal day 2 through 14. Adult male and female mice were tested for social behavior in the social interaction test and for individual behavior in the plus-maze and open-field tests. Female mice exposed to maternal separation had increased social behavior and increased anxiety. MS male mice had no changes in social behavior but had significantly disrupted individual behavior, including locomotor and exploratory activity. Handling had positive effects on social behavior in males and females and decreased anxiety in males. Our results support the hypothesis that brief separation of pups from their mothers (handling, which can be considered as moderate stress, may result in future positive changes in behavior. Maternal separation has deleterious effects on individual behavior and significant sex-specific effects on social behavior.

Multiple stressor effects in Chlamydomonas reinhardtii – Toward understanding mechanisms of interaction between effects of ultraviolet radiation and chemical pollutants

Energy Technology Data Exchange (ETDEWEB)

Korkaric, Muris [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, 8600, Duebendorf (Switzerland); ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics, 8092 Zürich (Switzerland); Behra, Renata; Fischer, Beat B. [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, 8600, Duebendorf (Switzerland); Junghans, Marion [Swiss Center for Applied Ecotoxicology Eawag-EPFL, 8600, Duebendorf (Switzerland); Eggen, Rik I.L., E-mail: rik.eggen@eawag.ch [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Environmental Toxicology, 8600, Duebendorf (Switzerland); ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics, 8092 Zürich (Switzerland)

2015-05-15

Highlights: • Systematic study of multiple stressor effects of UVR and chemicals in C. reinhardtii. • UVR and chemicals did not act independently on algal photosynthesis and reproduction. • Multiple stressor effects of UVR and chemicals depended on chemical MOA. • Synergistic effect interactions not limited to oxidative stress inducing chemicals. • Multiple MOAs of UVR may limit applicability of current prediction models. - Abstract: The effects of chemical pollutants and environmental stressors, such as ultraviolet radiation (UVR), can interact when organisms are simultaneously exposed, resulting in higher (synergistic) or lower (antagonistic) multiple stressor effects than expected based on the effects of single stressors. Current understanding of interactive effects is limited due to a lack of mechanism-based multiple stressor studies. It has been hypothesized that effect interactions may generally occur if chemical and non-chemical stressors cause similar physiological effects in the organism. To test this hypothesis, we exposed the model green alga Chlamydomonas reinhardtii to combinations of UVR and single chemicals displaying modes of action (MOA) similar or dissimilar to the impact of UVR on photosynthesis. Stressor interactions were analyzed based on the independent action model. Effect interactions were found to depend on the MOA of the chemicals, and also on their concentrations, the exposure time and the measured endpoint. Indeed, only chemicals assumed to cause effects on photosynthesis similar to UVR showed interactions with UVR on photosynthetic yield: synergistic in case of Cd(II) and paraquat and antagonistic in case of diuron. No interaction on photosynthesis was observed for S-metolachlor, which acts dissimilarly to UVR. However, combined effects of S-metolachlor and UVR on algal reproduction were synergistic, highlighting the importance of considering additional MOA of UVR. Possible mechanisms of stressor effect interactions are

Multiple stressor effects in Chlamydomonas reinhardtii – Toward understanding mechanisms of interaction between effects of ultraviolet radiation and chemical pollutants

International Nuclear Information System (INIS)

Korkaric, Muris; Behra, Renata; Fischer, Beat B.; Junghans, Marion; Eggen, Rik I.L.

2015-01-01

Highlights: • Systematic study of multiple stressor effects of UVR and chemicals in C. reinhardtii. • UVR and chemicals did not act independently on algal photosynthesis and reproduction. • Multiple stressor effects of UVR and chemicals depended on chemical MOA. • Synergistic effect interactions not limited to oxidative stress inducing chemicals. • Multiple MOAs of UVR may limit applicability of current prediction models. - Abstract: The effects of chemical pollutants and environmental stressors, such as ultraviolet radiation (UVR), can interact when organisms are simultaneously exposed, resulting in higher (synergistic) or lower (antagonistic) multiple stressor effects than expected based on the effects of single stressors. Current understanding of interactive effects is limited due to a lack of mechanism-based multiple stressor studies. It has been hypothesized that effect interactions may generally occur if chemical and non-chemical stressors cause similar physiological effects in the organism. To test this hypothesis, we exposed the model green alga Chlamydomonas reinhardtii to combinations of UVR and single chemicals displaying modes of action (MOA) similar or dissimilar to the impact of UVR on photosynthesis. Stressor interactions were analyzed based on the independent action model. Effect interactions were found to depend on the MOA of the chemicals, and also on their concentrations, the exposure time and the measured endpoint. Indeed, only chemicals assumed to cause effects on photosynthesis similar to UVR showed interactions with UVR on photosynthetic yield: synergistic in case of Cd(II) and paraquat and antagonistic in case of diuron. No interaction on photosynthesis was observed for S-metolachlor, which acts dissimilarly to UVR. However, combined effects of S-metolachlor and UVR on algal reproduction were synergistic, highlighting the importance of considering additional MOA of UVR. Possible mechanisms of stressor effect interactions are

The 5-HTTLPR polymorphism moderates the effect of stressful life events on drinking behavior in college students of African descent.

Science.gov (United States)

Kranzler, Henry R; Scott, Denise; Tennen, Howard; Feinn, Richard; Williams, Carla; Armeli, Stephen; Taylor, Robert E; Briggs-Gowan, Margaret J; Covault, Jonathan

2012-07-01

Covault et al. [Covault et al. (2007); Biol Psychiatry 61(5): 609-616] reported that the common functional polymorphism, 5-HTTLPR, in the serotonin transporter gene moderated the association between past-year stressful events and daily reports of drinking in a sample of European-American (EA) college students. We examined this effect in college students of African descent. Students recruited at a Historically Black University (n = 564) completed web-based measures of past-year stressful life experiences and daily reports of drinking and heavy drinking over a 30-day period. Participants were genotyped for the tri-allelic 5-HTTLPR polymorphism and dichotomized as low-activity S' allele carriers or high-activity L' homozygotes. Generalized linear models were used to examine the effects of life stress, genotype, and their interaction on the two drinking measures. In students who completed 15 or more daily surveys (n = 393), there was a significant interaction of past-year stressful events, 5-HTTLPR genotype, and gender on the number of drinking days (P = 0.002). Similar findings were obtained in relation to heavy drinking days (P = 0.007). Men showed a main effect of past-year stressful events on both drinking outcomes (P's life stressors on the frequency of drinking and heavy drinking days (P's stressful events were associated with more frequent drinking and heavy drinking, an effect that was moderated by the 5-HTTLPR polymorphism. However, in contrast to the findings in EA students, in the current sample, 5-HTTLPR moderated the association only among women. Copyright © 2012 Wiley Periodicals, Inc.

Effect of Thickness Stress in Stretch-Bending

NARCIS (Netherlands)

van den Boogaard, Antonius H.; Emmens, W.C.; Huetink, Han; Barlat, F; Moon, Y.H.; Lee, M.G.

2010-01-01

In any situation where a strip is pulled over a curved tool, locally a contact stress acts on the strip in thickness direction. This contact stress changes the stress state in the material, which will influence the deformation. One effect is that the yield stress in the plane of the strip is

Converging, Synergistic Actions of Multiple Stress Hormones Mediate Enduring Memory Impairments after Acute Simultaneous Stresses.

Science.gov (United States)

Chen, Yuncai; Molet, Jenny; Lauterborn, Julie C; Trieu, Brian H; Bolton, Jessica L; Patterson, Katelin P; Gall, Christine M; Lynch, Gary; Baram, Tallie Z

2016-11-02

Stress influences memory, an adaptive process crucial for survival. During stress, hippocampal synapses are bathed in a mixture of stress-released molecules, yet it is unknown whether or how these interact to mediate the effects of stress on memory. Here, we demonstrate novel synergistic actions of corticosterone and corticotropin-releasing hormone (CRH) on synaptic physiology and dendritic spine structure that mediate the profound effects of acute concurrent stresses on memory. Spatial memory in mice was impaired enduringly after acute concurrent stresses resulting from loss of synaptic potentiation associated with disrupted structure of synapse-bearing dendritic spines. Combined application of the stress hormones corticosterone and CRH recapitulated the physiological and structural defects provoked by acute stresses. Mechanistically, corticosterone and CRH, via their cognate receptors, acted synergistically on the spine-actin regulator RhoA, promoting its deactivation and degradation, respectively, and destabilizing spines. Accordingly, blocking the receptors of both hormones, but not each alone, rescued memory. Therefore, the synergistic actions of corticosterone and CRH at hippocampal synapses underlie memory impairments after concurrent and perhaps also single, severe acute stresses, with potential implications to spatial memory dysfunction in, for example, posttraumatic stress disorder. Stress influences memory, an adaptive process crucial for survival. During stress, adrenal corticosterone and hippocampal corticotropin-releasing hormone (CRH) permeate memory-forming hippocampal synapses, yet it is unknown whether (and how) these hormones interact to mediate effects of stress. Here, we demonstrate novel synergistic actions of corticosterone and CRH on hippocampal synaptic plasticity and spine structure that mediate the memory-disrupting effects of stress. Combined application of both hormones provoked synaptic function collapse and spine disruption

The Mutual Effect of Marital Quality and Parenting Stress on Child and Parent Depressive Symptoms in Families of Children with Oppositional Defiant Disorder.

Science.gov (United States)

Lin, Xiuyun; Zhang, Yulin; Chi, Peilian; Ding, Wan; Heath, Melissa A; Fang, Xiaoyi; Xu, Shousen

2017-01-01

The purpose of the current study was to examine the mutual relationships between dyadic level (i.e., marital quality and parenting stress) and individual level factors (i.e., children and parental depressive symptoms) in families of children with Oppositional Defiant Disorder (ODD). Specifically, we explored whether marital interaction (marital quality) was associated with symptoms of child depression through parent-child interaction (parenting stress) and parent depressive symptoms. We also explored whether parent-child interaction was associated with symptoms of parent depression through marital interaction and child depressive symptoms. This study was conducted with 256 parent-child dyads, consisting of children with ODD and one of each child's parents. Participants were recruited from 14 primary schools located in northern, eastern, and southwestern China. Results revealed that marital quality predicted symptoms of child depression through the parenting stress, but not parent depressive symptoms; and parenting stress predicted symptoms of parent depression through marital quality, but not through child depressive symptoms. Also, parenting stress significantly and directly predicted parent depressive symptoms. We concluded in families of children with ODD, the association of marital interaction and parent-child interaction on both symptoms of parent and child depression highlighted the mutual effects of the couple subsystem and the parent-child subsystem. Furthermore, in regard to parental and child depressive symptoms, implications for intervention are provided.

The Mutual Effect of Marital Quality and Parenting Stress on Child and Parent Depressive Symptoms in Families of Children with Oppositional Defiant Disorder

Directory of Open Access Journals (Sweden)

Xiuyun Lin

2017-10-01

Full Text Available The purpose of the current study was to examine the mutual relationships between dyadic level (i.e., marital quality and parenting stress and individual level factors (i.e., children and parental depressive symptoms in families of children with Oppositional Defiant Disorder (ODD. Specifically, we explored whether marital interaction (marital quality was associated with symptoms of child depression through parent-child interaction (parenting stress and parent depressive symptoms. We also explored whether parent-child interaction was associated with symptoms of parent depression through marital interaction and child depressive symptoms. This study was conducted with 256 parent-child dyads, consisting of children with ODD and one of each child's parents. Participants were recruited from 14 primary schools located in northern, eastern, and southwestern China. Results revealed that marital quality predicted symptoms of child depression through the parenting stress, but not parent depressive symptoms; and parenting stress predicted symptoms of parent depression through marital quality, but not through child depressive symptoms. Also, parenting stress significantly and directly predicted parent depressive symptoms. We concluded in families of children with ODD, the association of marital interaction and parent-child interaction on both symptoms of parent and child depression highlighted the mutual effects of the couple subsystem and the parent-child subsystem. Furthermore, in regard to parental and child depressive symptoms, implications for intervention are provided.

The Mutual Effect of Marital Quality and Parenting Stress on Child and Parent Depressive Symptoms in Families of Children with Oppositional Defiant Disorder

Science.gov (United States)

Lin, Xiuyun; Zhang, Yulin; Chi, Peilian; Ding, Wan; Heath, Melissa A.; Fang, Xiaoyi; Xu, Shousen

2017-01-01

The purpose of the current study was to examine the mutual relationships between dyadic level (i.e., marital quality and parenting stress) and individual level factors (i.e., children and parental depressive symptoms) in families of children with Oppositional Defiant Disorder (ODD). Specifically, we explored whether marital interaction (marital quality) was associated with symptoms of child depression through parent-child interaction (parenting stress) and parent depressive symptoms. We also explored whether parent-child interaction was associated with symptoms of parent depression through marital interaction and child depressive symptoms. This study was conducted with 256 parent-child dyads, consisting of children with ODD and one of each child's parents. Participants were recruited from 14 primary schools located in northern, eastern, and southwestern China. Results revealed that marital quality predicted symptoms of child depression through the parenting stress, but not parent depressive symptoms; and parenting stress predicted symptoms of parent depression through marital quality, but not through child depressive symptoms. Also, parenting stress significantly and directly predicted parent depressive symptoms. We concluded in families of children with ODD, the association of marital interaction and parent-child interaction on both symptoms of parent and child depression highlighted the mutual effects of the couple subsystem and the parent-child subsystem. Furthermore, in regard to parental and child depressive symptoms, implications for intervention are provided. PMID:29104548

The effect of physical activity on sleep quality, well-being, and affect in academic stress periods

Directory of Open Access Journals (Sweden)

Wunsch K

2017-04-01

Full Text Available Kathrin Wunsch, Nadine Kasten, Reinhard Fuchs Department of Sport Science, Sport Psychology Unit, Albert-Ludwigs University Freiburg, Freiburg im Breisgau, Germany Abstract: The stress-buffering hypothesis postulates that physical activity and exercise can buffer the negative effects of (academic stress on health. It still remains an open question whether students, who regularly engage in physical activity and exercise within their academic examination period, can successfully diminish these negative effects. Sixty-four subjects participated in this study and completed a total of five surveys, with T1 at the end of the semester break (baseline and T2–T5 being presented every Friday in the last 4 weeks of the semester (examination period. They were asked to answer questions about their activity level, sleep quality, well-being and affect. Hierarchical linear models showed significant dependencies on time for all dependent measures. The expansion of the model for exercise also showed significant main effects of this predictor on well-being and positive affect (PA and negative affect. Moreover, significant interactions with time for sleep quality and PA were found. Results suggest that physical activity and exercise in the academic examination period may be able to buffer the negative effects of stress on health-related outcomes. Therefore, activity levels should be maintained in times of high stress to prevent negative effects on sleep, well-being and affect in students. Keywords: examination stress, exercise, stress-buffering hypothesis

Indomethacin counteracts the effects of chronic social defeat stress on emotional but not recognition memory in mice.

Science.gov (United States)

Duque, Aránzazu; Vinader-Caerols, Concepción; Monleón, Santiago

2017-01-01

We have previously observed the impairing effects of chronic social defeat stress (CSDS) on emotional memory in mice. Given the relation between stress and inflammatory processes, we sought to study the effectiveness of the anti-inflammatory indomethacin in reversing the detrimental effects of CSDS on emotional memory in mice. The effects of CSDS and indomethacin on recognition memory were also evaluated. Male CD1 mice were randomly divided into four groups: non-stressed + saline (NS+SAL); non-stressed + indomethacin (NS+IND); stressed + saline (S+SAL); and stressed + indomethacin (S+IND). Stressed animals were exposed to a daily 10 min agonistic confrontation (CSDS) for 20 days. All subjects were treated daily with saline or indomethacin (10 mg/kg, i.p.). 24 h after the CSDS period, all the mice were evaluated in a social interaction test to distinguish between those that were resilient or susceptible to social stress. All subjects (n = 10-12 per group) were then evaluated in inhibitory avoidance (IA), novel object recognition (NOR), elevated plus maze and hot plate tests. As in control animals (NS+SAL group), IA learning was observed in the resilient groups, as well as in the susceptible mice treated with indomethacin (S+IND group). Recognition memory was observed in the non-stressed and the resilient mice, but not in the susceptible animals. Also, stressed mice exhibited higher anxiety levels. No significant differences were observed in locomotor activity or analgesia. In conclusion, CSDS induces anxiety in post-pubertal mice and impairs emotional and recognition memory in the susceptible subjects. The effects of CSDS on emotional memory, but not on recognition memory and anxiety, are reversed by indomethacin. Moreover, memory impairment is not secondary to the effects of CSDS on locomotor activity, emotionality or pain sensitivity.

Indomethacin counteracts the effects of chronic social defeat stress on emotional but not recognition memory in mice.

Directory of Open Access Journals (Sweden)

Aránzazu Duque

Full Text Available We have previously observed the impairing effects of chronic social defeat stress (CSDS on emotional memory in mice. Given the relation between stress and inflammatory processes, we sought to study the effectiveness of the anti-inflammatory indomethacin in reversing the detrimental effects of CSDS on emotional memory in mice. The effects of CSDS and indomethacin on recognition memory were also evaluated. Male CD1 mice were randomly divided into four groups: non-stressed + saline (NS+SAL; non-stressed + indomethacin (NS+IND; stressed + saline (S+SAL; and stressed + indomethacin (S+IND. Stressed animals were exposed to a daily 10 min agonistic confrontation (CSDS for 20 days. All subjects were treated daily with saline or indomethacin (10 mg/kg, i.p.. 24 h after the CSDS period, all the mice were evaluated in a social interaction test to distinguish between those that were resilient or susceptible to social stress. All subjects (n = 10-12 per group were then evaluated in inhibitory avoidance (IA, novel object recognition (NOR, elevated plus maze and hot plate tests. As in control animals (NS+SAL group, IA learning was observed in the resilient groups, as well as in the susceptible mice treated with indomethacin (S+IND group. Recognition memory was observed in the non-stressed and the resilient mice, but not in the susceptible animals. Also, stressed mice exhibited higher anxiety levels. No significant differences were observed in locomotor activity or analgesia. In conclusion, CSDS induces anxiety in post-pubertal mice and impairs emotional and recognition memory in the susceptible subjects. The effects of CSDS on emotional memory, but not on recognition memory and anxiety, are reversed by indomethacin. Moreover, memory impairment is not secondary to the effects of CSDS on locomotor activity, emotionality or pain sensitivity.

Minority stress and relationship functioning among young male same-sex couples: An examination of actor-partner interdependence models.

Science.gov (United States)

Feinstein, Brian A; McConnell, Elizabeth; Dyar, Christina; Mustanski, Brian; Newcomb, Michael E

2018-05-01

In different-sex couples, individual and partner stress can both have a negative impact on relationship functioning (actor and partner effects). Gay and bisexual men experience unique stress (sexual minority stress), but few studies have examined the effects of this stress on relationship functioning among young male couples. The current study examined (a) actor and partner effects of general and minority stress (internalized stigma, microaggressions, victimization, and outness) on relationship functioning (relationship quality and negative relationship interactions), (b) interactions between individual and partner stress as predictors of relationship functioning, and (c) dyadic coping and relationship length as moderators of actor and partner effects. Actor-partner interdependence models were tested using data from 153 young male couples. There was strong support for actor effects. Higher general stress and internalized stigma were associated with lower relationship quality, but only for those in longer relationships. Additionally, higher general stress, internalized stigma, and microaggressions, and lower outness, were associated with more negative relationship interactions. There was limited support for partner effects. Having a partner with higher internalized stigma was associated with more negative relationship interactions, but none of the other partner effects were significant. There was no support for individual and partner stress interacting to predict relationship functioning or for dyadic coping as a stress buffer. Findings highlight the influence of one's own experiences of general and minority stress on relationship functioning, but raise questions about how partner stress influences relationship functioning among young male couples. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

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

Science.gov (United States)

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.

Effect of axial stress on the transient mechanical response of 20%, cold-worked Type 316 stainless-steel cladding

International Nuclear Information System (INIS)

Yamada, H.

1979-01-01

To understand the effects of the fuel-cladding mechanical interaction on the failure of 20% cold-worked Type 316 stainless-steel cladding during anticipated nuclear reactor transients, the transient mechanical response of the cladding was investigated using a transient tube burst method at a heating rate of 5.6 0 C/s and axial-to-hoop-stress ratios in the range of 1/2 to 2. The failure temperatures were observed to remain essentially constant for the transient tests at axial-to-hoop-stress ratios between 1/2 and 1, but to decrease with an increase in axial-to-hoop-stress ratios above unity. The uniform diametral strains to failure were observed to decrease monotonically with an increase in axial-to-hoop-stress ratio from 1/2 to 2, and in general, the uniform axial strains to failure were observed to increase with an increase in axial-to-hoop-stress ratio. The fracture of the cladding during thermal transients was found to be strongly affected by the maximum principal stress but not by the effective stress

The effect of residual stress relaxation by the vibratory stress relief technique on the textures of grains in AA 6061 aluminum alloy

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Wang, Jia-Siang; Hsieh, Chih-Chun; Lin, Chi-Ming; Chen, Erh-Chiang; Kuo, Che-Wei; Wu, Weite, E-mail: wwu@dragon.nchu.edu.tw

2014-05-01

The textures and crystallographic orientations beneath the treatment area in AA 6061 aluminum alloy after vibratory stress relief (VSR) process were investigated by combining the electron backscatter diffraction analysis of the misoriented low- or high-angle boundaries, the (inverse) pole figures, the line scans and the various grain orientations. The relaxation effect caused by compressive residual stress in the intermediate region is superior to that of tensile residual stress on both sides of the cantilever by means of X-ray diffraction techniques. The residual stress relaxation that occurs due to vibrational stress excitation accompanies the “orientation of banding” disintegration, the decreases in the dislocation density, the strain energy, and the fraction of low-angle boundaries within each type of grain orientation, such as Copper {112} 〈111〉, S {123} 〈634〉, Goss {110} 〈001〉, and Brass {110} 〈112〉, excepting the Cube (or near-Cube) {100} 〈001〉 grain orientation. The maintained invariance in the Cube texture can be attributed to the maximum number of active primary slip systems, resulting in an interaction that results from hindered slip on intersecting families of the planes.

The effect of residual stress relaxation by the vibratory stress relief technique on the textures of grains in AA 6061 aluminum alloy

International Nuclear Information System (INIS)

Wang, Jia-Siang; Hsieh, Chih-Chun; Lin, Chi-Ming; Chen, Erh-Chiang; Kuo, Che-Wei; Wu, Weite

2014-01-01

The textures and crystallographic orientations beneath the treatment area in AA 6061 aluminum alloy after vibratory stress relief (VSR) process were investigated by combining the electron backscatter diffraction analysis of the misoriented low- or high-angle boundaries, the (inverse) pole figures, the line scans and the various grain orientations. The relaxation effect caused by compressive residual stress in the intermediate region is superior to that of tensile residual stress on both sides of the cantilever by means of X-ray diffraction techniques. The residual stress relaxation that occurs due to vibrational stress excitation accompanies the “orientation of banding” disintegration, the decreases in the dislocation density, the strain energy, and the fraction of low-angle boundaries within each type of grain orientation, such as Copper {112} 〈111〉, S {123} 〈634〉, Goss {110} 〈001〉, and Brass {110} 〈112〉, excepting the Cube (or near-Cube) {100} 〈001〉 grain orientation. The maintained invariance in the Cube texture can be attributed to the maximum number of active primary slip systems, resulting in an interaction that results from hindered slip on intersecting families of the planes

Moderating effects of coping on work stress and job performance for nurses in tertiary hospitals: a cross-sectional survey in China.

Science.gov (United States)

Li, Li; Ai, Hua; Gao, Lei; Zhou, Hao; Liu, Xinyan; Zhang, Zhong; Sun, Tao; Fan, Lihua

2017-06-12

Work stress is a major problem for nurses and it can negatively influence job performance. Therefore, it is critical to explore variables that can reduce or buffer the negative effects of work stress. This study explores the moderating effects of coping strategies on the relationship between work stress and job performance for nurses in China. A cross-sectional survey of 852 nurses from four tertiary hospitals in Heilongjiang Province, China, was conducted in 2013. Descriptive statistics were reported for socioeconomic status and demographic characteristics, level of work stress, coping strategies, and job performance. Regression analysis was conducted to test the interaction between work stress and coping strategies on job performance. Three subscales of work stress were negatively related to job performance. Positive coping strategies moderated Patient Care and job performance while negative coping strategies moderated Workload and Time and performance, and between Working Environment and Resources and performance. Positive coping strategies reduce or buffer the negative effects of work stress on job performance and negative coping strategies increased the negative effects.

Individual differences in the effects of chronic stress on memory: behavioral and neurochemical correlates of resiliency.

Science.gov (United States)

Sweis, B M; Veverka, K K; Dhillon, E S; Urban, J H; Lucas, L R

2013-08-29

Chronic stress has been shown to impair memory, however, the extent to which memory can be impaired is often variable across individuals. Predisposed differences in particular traits, such as anxiety, may reveal underlying neurobiological mechanisms that could be driving individual differences in sensitivity to stress and, thus, stress resiliency. Such pre-morbid characteristics may serve as early indicators of susceptibility to stress. Neuropeptide Y (NPY) and enkephalin (ENK) are neurochemical messengers of interest implicated in modulating anxiety and motivation circuitry; however, little is known about how these neuropeptides interact with stress resiliency and memory. In this experiment, adult male rats were appetitively trained to locate sugar rewards in a motivation-based spatial memory task before undergoing repeated immobilization stress and then being tested for memory retention. Anxiety-related behaviors, among other characteristics, were monitored longitudinally. Results indicated that stressed animals which showed little to no impairments in memory post-stress (i.e., the more stress-resilient individuals) exhibited lower anxiety levels prior to stress when compared to stressed animals that showed large deficits in memory (i.e., the more stress-susceptible individuals). Interestingly, all stressed animals, regardless of memory change, showed reduced body weight gain as well as thymic involution, suggesting that the effects of stress on metabolism and the immune system were dissociated from the effects of stress on higher cognition, and that stress resiliency seems to be domain-specific rather than a global characteristic within an individual. Neurochemical analyses revealed that NPY in the hypothalamus and amygdala and ENK in the nucleus accumbens were modulated differentially between stress-resilient and stress-susceptible individuals, with elevated expression of these neuropeptides fostering anxiolytic and pro-motivation function, thus driving

Early-Life Adversity Interacts with FKBP5 Genotypes: Altered Working Memory and Cardiac Stress Reactivity in the Oklahoma Family Health Patterns Project.

Science.gov (United States)

Lovallo, William R; Enoch, Mary-Anne; Acheson, Ashley; Cohoon, Andrew J; Sorocco, Kristen H; Hodgkinson, Colin A; Vincent, Andrea S; Goldman, David

2016-06-01

Exposure to stress during critical periods of development can have adverse effects on adult health behaviors, and genetic vulnerabilities may enhance these stress effects. We carried out an exploratory examination of psychological, physiological, and behavioral characteristics of 252 healthy young adults for the impact of early-life adversity (ELA) in relation to the G-to-A single nucleotide polymorphism (SNP), rs9296158, of the FKBP5 gene. FKBP5 is a molecular cochaperone that contributes to the functional status of the glucocorticoid receptor (GR) and to the quality of corticosteroid signaling. FKBP5 expression is upregulated by cortisol exposure during stressful episodes, with greater upregulation seen in A-allele carriers. As such, FKBP5 expression and GR function may be environmentally sensitive in A-allele carriers and therefore suitable for the study of gene-by-environment (G × E) interactions. Compared with FKBP5, GG homozygotes (N=118), A-allele carriers (N = 132) without psychiatric morbidity had progressively worse performance on the Stroop color-word task with increasing levels of ELA exposure (Genotype × ELA, F=5.14, P=0.007), indicating a G × E interaction on working memory in early adulthood. In addition, heart rate response to mental stress was diminished overall in AA/AG-allele carriers (F=5.15, P=0.024). Diminished working memory and attenuated autonomic responses to stress are both associated with risk for alcoholism and other substance use disorders. The present data suggest that FKBP5 in the GR pathway may be a point of vulnerability to ELA, as seen in this group of non-traumatized young adults. FKBP5 is accordingly a potential target for more extensive studies of the impact of ELA on health and health behaviors in adulthood.

Psychosocial and psychophysiological effects of human-animal interactions: the possible role of oxytocin

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Andrea eBeetz

2012-07-01

Full Text Available During the last decade it has become more widely accepted that pet-ownership and animal-assistance in therapy and education may have a multitude of positive effects on humans. Here, we review the evidence from 67 original studies on human-animal interactions (HAI which met our inclusion criteria with regard to sample size, peer-review and standard scientific research design. Among the well-documented effects of HAI in humans of different ages, with and without special medical or mental health conditions are benefits for: social attention, social behavior, interpersonal interactions and mood; stress-related parameters such as cortisol, heart rate, and blood pressure; self-reported fear and anxiety; and mental and physical health, especially cardiovascular diseases. Limited evidence exists for positive effects of HAI on: reduction of stress-related parameters such as epinephrine and norepinephrine; improvement of immune system functioning and pain management; increased trustworthiness of and trust towards other persons; reduced aggression; enhanced empathy and improved learning. We propose that the activation of the oxytocin system plays a key role in the majority of these reported psychological and psychophysiological effects of HAI. Oxytocin and HAI effects largely overlap, as documented by research in both, humans and animals, and first studies found that HAI affects the oxytocin system. As a common underlying mechanism, the activation of the oxytocin system does not only provide an explanation, but also allows an integrative view of the different effects of HAI.

The induction of thioredoxin-1 by epinephrine withdraws stress via interaction with β-arrestin-1

Science.gov (United States)

Jia, Jin-Jing; Zeng, Xian-Si; Zhou, Xiao-Shuang; Li, Ye; Bai, Jie

2014-01-01

Stress regulates a panel of important physiological functions and disease states. Epinephrine is produced under stresses threaten to homeostasis. Thioredoxin-1(Trx-1) is a redox regulating protein which is induced to resist stresses and related with various diseases. Thus, it is important to examine whether Trx-1 is induced by epinephrine and to understand the underlying molecular mechanisms that Trx-1 modulates epinephrine stress. Here, we show that the expression of Trx-1 was induced by epinephrine via β-adrenergic receptor/Cyclic AMP/protein kinase A (PKA) signaling pathway in PC12 cells. The down-regulation of Trx-1 by siRNA aggravated accumulation of γ-H2AX and further decreased expression of p53 by epinephrine. Accordingly, Trx-1 overexpression alleviated accumulation of γ-H2AX and restored the expressions of p53 and C/EBP homologous protein (CHOP) in the cortex, hippocampus and thymus of mice. Moreover, Trx-1 overexpression reduced the malondialdehyde concentration by epinephrine. We further explored the mechanism on p53 and γ-H2AX regulated by Trx-1. We found that overexpression of Trx-1 suppressed β-arrestin-1 expression through interaction with β-arrestin-1. Consequently, the downregulation of β-arrestin-1 suppressed the cell viability and the expressions of γ-H2AX and cyclin D1, and increased p53 expression. Taken together, our data suggest that Trx-1/β-arrestin-1 interaction may represent a novel endogenous mechanism on protecting against stress. PMID:25486571

Interactive effects of copper stress and arbuscular mycorrhizal fungi on photosynthetic characteristics and chlorphyl fluorescence parameters of elsholtzia splendens

International Nuclear Information System (INIS)

Li, Y.; Jin, Z.; Li, J.

2017-01-01

To determine interactive effects of added copper (Cu) and arbuscular mycorrhizal fungi (AMF) inoculation on the photosynthesis of Elsholtzia splendens, a greenhouse pot experiment was conducted. Four treatments were used, including -Cu-AMF (no Cu addition and no AMF inoculation), +Cu-AMF (Cu addition but no AMF inoculation), -Cu+AMF (no Cu addition and AMF inoculation), and +Cu+AMF (Cu addition and AMF inoculation). Cu addition did not change diurnal variation curves of the net photosynthetic rate(PN), the intercellular CO/sub 2/ concentration (Ci), the stomatal conductance (gs), or the transpiration rate (E); however, it significantly decreased the daily mean PN, gs, E, light-use efficiency (LUE), and carboxylation efficiency (CE). Furthermore, AMF inoculation significantly increased the daily mean PN, gs, LUE, and CE of E. splendens. In response to light, Cu addition significantly decreased the light-saturated net photosynthetic rate (PNmax), the light saturation point (LSP), the light compensation point (LCP), and the apparent quantum yield (AQY), while AMF inoculation significantly increased PNmax and AQY. In response to the CO/sub 2/ concentration, Cu addition significantly decreased PNmax and the CO/sub 2/ saturation point (CSP), while AMF inoculation significantly increased PNmax. Both Cu addition and AMF inoculation significantly decreased the relative chlorophyll content. Compared to the negative control treatment (-Cu-AMF), Cu addition significantly increased the minimal fluorescence, but significantly decreased maximal fluorescence, variable fluorescence,and maximum photochemical efficiency of PSII. These results suggest that AMF inoculations alleviate the inhibitory effect of copper stress on E. splendens plants by weakening its toxic effects on the photosynthetic apparatus and pigments. (author)

Inverse strain rate effect on cyclic stress response in annealed Zircaloy-2

Energy Technology Data Exchange (ETDEWEB)

Sudhakar Rao, G.; Verma, Preeti [Center of Advanced Study, Department of Metallurgical Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India); Chakravartty, J.K. [Mechanical Metallurgy Group, Bhabha Atomic Research Center, Trombay 400 085, Mumbai (India); Nudurupati, Saibaba [Nuclear Fuel Complex, Hyderabad 500 062 (India); Mahobia, G.S.; Santhi Srinivas, N.C. [Center of Advanced Study, Department of Metallurgical Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India); Singh, Vakil, E-mail: vsingh.met@itbhu.ac.in [Center of Advanced Study, Department of Metallurgical Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India)

2015-02-15

Low cycle fatigue behavior of annealed Zircaloy-2 was investigated at 300 and 400 °C at different strain amplitudes and strain rates of 10{sup −2}, 10{sup −3}, and 10{sup −4} s{sup −1}. Cyclic stress response showed initial hardening with decreasing rate of hardening, followed by linear cyclic hardening and finally secondary hardening with increasing rate of hardening for low strain amplitudes at both the temperatures. The rate as well the degree of linear hardening and secondary hardening decreased with decrease in strain rate at 300 °C, however, there was inverse effect of strain rate on cyclic stress response at 400 °C and cyclic stress was increased with decrease in strain rate. The fatigue life decreased with decrease in strain rate at both the temperatures. The occurrence of linear cyclic hardening, inverse effect of strain rate on cyclic stress response and deterioration in fatigue life with decrease in strain rate may be attributed to dynamic strain aging phenomena resulting from enhanced interaction of dislocations with solutes. Fracture surfaces revealed distinct striations, secondary cracking, and oxidation with decrease in strain rate. Deformation substructure showed parallel dislocation lines and dislocation band structure at 300 °C. Persistent slip band wall structure and development of fine Corduroy structure was observed at 400 °C.

Inverse strain rate effect on cyclic stress response in annealed Zircaloy-2

International Nuclear Information System (INIS)

Sudhakar Rao, G.; Verma, Preeti; Chakravartty, J.K.; Nudurupati, Saibaba; Mahobia, G.S.; Santhi Srinivas, N.C.; Singh, Vakil

2015-01-01

Low cycle fatigue behavior of annealed Zircaloy-2 was investigated at 300 and 400 °C at different strain amplitudes and strain rates of 10 −2 , 10 −3 , and 10 −4 s −1 . Cyclic stress response showed initial hardening with decreasing rate of hardening, followed by linear cyclic hardening and finally secondary hardening with increasing rate of hardening for low strain amplitudes at both the temperatures. The rate as well the degree of linear hardening and secondary hardening decreased with decrease in strain rate at 300 °C, however, there was inverse effect of strain rate on cyclic stress response at 400 °C and cyclic stress was increased with decrease in strain rate. The fatigue life decreased with decrease in strain rate at both the temperatures. The occurrence of linear cyclic hardening, inverse effect of strain rate on cyclic stress response and deterioration in fatigue life with decrease in strain rate may be attributed to dynamic strain aging phenomena resulting from enhanced interaction of dislocations with solutes. Fracture surfaces revealed distinct striations, secondary cracking, and oxidation with decrease in strain rate. Deformation substructure showed parallel dislocation lines and dislocation band structure at 300 °C. Persistent slip band wall structure and development of fine Corduroy structure was observed at 400 °C

Relations between mothers' daily work, home, and relationship stress with characteristics of mother-child conflict interactions.

Science.gov (United States)

Nelson, Jackie A; Boyer, Brittany P; Villarreal, Deyaun L; Smith, Olivia A

2017-06-01

This study examined whether daily variations in levels of mothers' work, home, and relationship stress were related to collaborative and oppositional qualities of mother-child conflict interactions across 1 week. Mothers reported on 1 specific conflict interaction with their 5- to 8-year-old child and their work, home, and relationship stress through online surveys each day for 7 consecutive days. Diary data from 142 mothers were analyzed in 6 multilevel models, each including within- and between-family levels of a stressor predicting collaborative or oppositional conflict qualities. Results suggested that families in the sample differed from each other, and also varied during the week, in collaborative and oppositional conflict qualities as well as stress in all 3 domains. Mothers reported a greater degree of oppositional conflict qualities on days characterized by higher perceptions of home chaos. Additionally, mothers who reported higher average levels of negativity in romantic relationships endorsed oppositional conflict qualities to a greater extent than mothers with lower relationship negativity. Two multilevel models including all 3 stressors in relation to collaborative and oppositional conflict revealed that for mothers managing multiple roles, average romantic relationship stress was the most important unique contributor to mother-child conflict qualities and daily relationship stress was particularly influential among mothers with sons compared to those with daughters. Results support the spillover hypothesis of stress within the family system and are discussed in terms of mothers' coping mechanisms and emotional engagement. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Interaction between diazepam and hippocampal corticosterone after acute stress: impact on memory in middle-aged mice

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Daniel eBeracochea

2011-04-01

Full Text Available Benzodiazepines (BDZ are widely prescribed in the treatment of anxiety disorders associated to aging. Interestingly, whereas a reciprocal interaction between the GABAergic system and HPA axis has been evidenced, there is to our knowledge no direct evaluation of the impact of BDZ on both hippocampus (HPC corticosterone concentrations and HPC-dependent memory in stressed middle-aged subjects. We showed previously that an acute stress induced in middle-aged mice severe memory impairments in a hippocampus-dependent task, and increased in parallel hippocampus corticosterone concentrations, as compared to non stressed middle-aged controls (Tronche et al., 2010. Based on these findings, the aims of the present study were to evidence the impact of diazepam (a positive allosteric modulator of the GABA-A receptor on HPC glucocorticoids concentrations and in parallel on HPC-dependent memory in acutely stressed middle-aged mice.Microdialysis experiments showed an interaction between diazepam doses and corticosterone concentrations into the HPC. From 0.25 mg/kg to 0.5 mg/kg, diazepam dose-dependently reduces intra-HPC corticosterone concentrations and in parallel, dose-dependently increased hippocampal-dependent memory performance. In contrast, the highest (1.0mg/kg diazepam dose induces a reduction in HPC corticosterone concentration, which was of greater magnitude as compared to the two other diazepam doses, but however decreased the hippocampal-dependent memory performance. In summary, our study provides first evidence that diazepam restores in stressed middle-aged animals the hippocampus-dependent response, in relation with HPC corticosterone concentrations. Overall, our data illustrate how stress and benzodiazepines could modulate cognitive functions depending on hippocampus activity.

Does Professional Development Reduce the Influence of Teacher Stress on Teacher-Child Interactions in Pre-Kindergarten Classrooms?

Science.gov (United States)

Sandilos, Lia E.; Goble, Priscilla; Rimm-Kaufman, Sara E.; Pianta, Robert C.

2018-01-01

The present study examines the extent to which participation in a 14-week professional development course designed to improve teacher-child interactions in the classroom moderated the relation between teacher-reported job stress and gains in observed teacher-child interaction quality from the beginning to the end of the intervention. Participants…

Mastication as a Stress-Coping Behavior.

Science.gov (United States)

Kubo, Kin-ya; Iinuma, Mitsuo; Chen, Huayue

2015-01-01

Exposure to chronic stress induces various physical and mental effects that may ultimately lead to disease. Stress-related disease has become a global health problem. Mastication (chewing) is an effective behavior for coping with stress, likely due to the alterations chewing causes in the activity of the hypothalamic-pituitary-adrenal axis and autonomic nervous system. Mastication under stressful conditions attenuates stress-induced increases in plasma corticosterone and catecholamines, as well as the expression of stress-related substances, such as neurotrophic factors and nitric oxide. Further, chewing reduces stress-induced changes in central nervous system morphology, especially in the hippocampus and hypothalamus. In rodents, chewing or biting on wooden sticks during exposure to various stressors reduces stress-induced gastric ulcer formation and attenuates spatial cognitive dysfunction, anxiety-like behavior, and bone loss. In humans, some studies demonstrate that chewing gum during exposure to stress decreases plasma and salivary cortisol levels and reduces mental stress, although other studies report no such effect. Here, we discuss the neuronal mechanisms that underline the interactions between masticatory function and stress-coping behaviors in animals and humans.

Effect of silicon and nanosilicon on reduction of damage caused by salt stress in maize (Zea mays seedlings

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Assieh Behdad

2015-12-01

Full Text Available Salinity reduced the efficiency of agricultural production like maize as one of the most important cereals for food and oil for humans. Silicon is the second most abundant element in the soil and alleviates the biotic and abiotic stresses in plants. The aim of this study is evaluate the effect of silicon and nanosilicon on improvement of salt stress in maize (Zea mays. For this propose, the interaction between the effects of different levels of salinity (0 and 100 mM, silicon and nanosilicon (50, 100 and 150 mg /mL was studied in completely randomized block design with factorial experiments and with three replications. The results showed that salinity significantly decreased root and shoot growth, amount of chlorophyll and carotenoid pigments, protein and potassium contents, compared to control. Treating plants with silicon and nanosilicon caused reduction of salinity effects and increase above indices. Salinity stress also caused a significant increase in proline, anthocyanin and soluble carbohydrate contents, lipid peroxidation, and catalase activity and treatment with silicon and nanosilicon alleviates effects of salt stress and reduced the amount of above indices. 150 mg/mL of nanosilicon showed the maximum effect on diminishing negative effects of salt stress on all examined parameters. So, the use of this element is proposed as alleviator of salt stress on maize.

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.