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Sample records for subjective stress ratings

  1. Medical students' subjective ratings of stress levels and awareness of student support services about mental health.

    Science.gov (United States)

    Walter, Garry; Soh, Nerissa Li-Wey; Norgren Jaconelli, Sanna; Lampe, Lisa; Malhi, Gin S; Hunt, Glenn

    2013-06-01

    To descriptively assess medical students' concerns for their mental and emotional state, perceived need to conceal mental problems, perceived level of support at university, knowledge and use of student support services, and experience of stresses of daily life. From March to September 2011, medical students at an Australian university were invited to complete an anonymous online survey. 475 responses were received. Students rated study and examinations (48.9%), financial concerns (38.1%), isolation (19.4%) and relationship concerns (19.2%) as very or extremely stressful issues. Knowledge of available support services was high, with 90.8% indicating they were aware of the university's medical centre. Treatment rates were modest (31.7%). Students' concerns about their mental state were generally low, but one in five strongly felt they needed to conceal their emotional problems. Despite widespread awareness of appropriate support services, a large proportion of students felt they needed to conceal mental and emotional problems. Overall treatment rates for students who were greatly concerned about their mental and emotional state appeared modest, and, although comparable with those of similarly aged community populations, may reflect undertreatment. It would be appropriate for universities to address stressors identified by students. Strategies for encouraging distressed students to obtain appropriate assessment and treatment should also be explored. Those students who do seek healthcare are most likely to see a primary care physician, suggesting an important screening role for these health professionals.

  2. Feeding rates affect stress and non-specific immune responses of juvenile blunt snout bream Megalobrama amblycephala subjected to hypoxia.

    Science.gov (United States)

    Li, Xiang-Fei; Xu, Chao; Tian, Hong-Yan; Jiang, Guang-Zhen; Zhang, Ding-Dong; Liu, Wen-Bin

    2016-02-01

    This study aimed to investigate the effects of feeding rates on stress response, innate immunity and hypoxia resistance of juvenile blunt snout bream Megalobrama amblycephala. Fish were randomly assigned to one of six feeding rates (2, 3, 4, 5, 6 and 7% of body weight/day) for 60 days. Then, fish were subjected to hypoxic conditions and haemato-immunological parameters were analyzed pre- and post-challenge. Low feed ration resulted in decreased liver superoxide dismutase and catalase activities and reduced glutathione contents. Inadequate feeding also adversely affected the immune functions of fish, as was characterized by the relatively low haemato-immunological parameters (including alternative complement (ACH50), myeloperoxidase (MPO), plasma protein profiles and transferring) and high hypoxia-induced mortality. High feed ration did not lead to the improvement in antioxidant capability, immune responses and survival. In addition, plasma cortisol, glucose and transferrin levels as well as lysozyme activities all increased significantly after hypoxia challenge, whereas the opposite was true for plasma ACH50 and MPO activities as well as protein profiles in terms of hypoxia challenge. An interaction between feeding rate and hypoxia was also observed in plasma cortisol, glucose and protein profiles. In conclusion, a feeding rate of 4-5% of body weight/day is optimal to boost the innate immunity of juvenile blunt snout bream. Low ration resulted in decreased antioxidant capability, compromised immune functions and reduced hypoxia resistance, while over feeding did not benefit the health status. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Aerobic exercise acutely prevents the endothelial dysfunction induced by mental stress among subjects with metabolic syndrome: the role of shear rate.

    Science.gov (United States)

    Sales, Allan R K; Fernandes, Igor A; Rocha, Natália G; Costa, Lucas S; Rocha, Helena N M; Mattos, João D M; Vianna, Lauro C; Silva, Bruno M; Nóbrega, Antonio C L

    2014-04-01

    Mental stress induces transient endothelial dysfunction, which is an important finding for subjects at cardiometabolic risk. Thus, we tested whether aerobic exercise prevents this dysfunction among subjects with metabolic syndrome (MetS) and whether an increase in shear rate during exercise plays a role in this phenomenon. Subjects with MetS participated in two protocols. In protocol 1 (n = 16), endothelial function was assessed using brachial artery flow-mediated dilation (FMD). Subjects then underwent a mental stress test followed by either 40 min of leg cycling or rest across two randomized sessions. FMD was assessed again at 30 and 60 min after exercise or rest, with a second mental stress test in between. Mental stress reduced FMD at 30 and 60 min after the rest session (baseline: 7.7 ± 0.4%, 30 min: 5.4 ± 0.5%, and 60 min: 3.9 ± 0.5%, P exercise prevented this reduction (baseline: 7.5 ± 0.4%, 30 min: 7.2 ± 0.7%, and 60 min: 8.7 ± 0.8%, P > 0.05 vs. baseline). Protocol 2 (n = 5) was similar to protocol 1 except that the first period of mental stress was followed by either exercise in which the brachial artery shear rate was attenuated via forearm cuff inflation or exercise without a cuff. Noncuffed exercise prevented the reduction in FMD (baseline: 7.5 ± 0.7%, 30 min: 7.0 ± 0.7%, and 60 min: 8.7 ± 0.8%, P > 0.05 vs. baseline), whereas cuffed exercise failed to prevent this reduction (baseline: 7.5 ± 0.6%, 30 min: 5.4 ± 0.8%, and 60 min: 4.1 ± 0.9%, P exercise prevented mental stress-induced endothelial dysfunction among subjects with MetS, and an increase in shear rate during exercise mediated this effect.

  4. A new method for calculating energy release rate in tunnel excavation subjected to high in situ stress

    Directory of Open Access Journals (Sweden)

    Xiao Qinghua

    2016-03-01

    Full Text Available Based on energy theory, energy release rate (EER and local energy release rate (LEER, a new index called FERR (Fractional Energy Release Rate is proposed, and this method can not only evaluate the risk of rock burst, but also can point out the location of high risk and the scale of rockburst. The FERR index is applied to the TBM assembling tunnel in Jinping Hydro Power Station II to evaluate the scale and intensity of rockburst, as well as the location where rockburst occurs. With FDM method adopted, the energy release rate of 3 excavation plans are calculated and the scale and risk of rockburst is evaluated, and the location of high risk of rockburst is also mapped. With FERR used in the evaluation, the rockburst is nicely controlled which ensured the safety and construction schedule of the project.

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

    Science.gov (United States)

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

    2017-12-01

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

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

    Science.gov (United States)

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

    2012-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Roselinde Kaiser Henderson

    2012-06-01

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

  8. Strain rate effects in stress corrosion cracking

    Energy Technology Data Exchange (ETDEWEB)

    Parkins, R.N. (Newcastle upon Tyne Univ. (UK). Dept. of Metallurgy and Engineering Materials)

    1990-03-01

    Slow strain rate testing (SSRT) was initially developed as a rapid, ad hoc laboratory method for assessing the propensity for metals an environments to promote stress corrosion cracking. It is now clear, however, that there are good theoretical reasons why strain rate, as opposed to stress per se, will often be the controlling parameter in determining whether or not cracks are nucleated and, if so, are propagated. The synergistic effects of the time dependence of corrosion-related reactions and microplastic strain provide the basis for mechanistic understanding of stress corrosion cracking in high-pressure pipelines and other structures. However, while this may be readily comprehended in the context of laboratory slow strain tests, its extension to service situations may be less apparent. Laboratory work involving realistic stressing conditions, including low-frequency cyclic loading, shows that strain or creep rates give good correlation with thresholds for cracking and with crack growth kinetics.

  9. Factors of subjective heat stress of urban citizens in contexts of everyday life

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    Kunz-Plapp, Tina; Hackenbruch, Julia; Schipper, Janus Willem

    2016-04-01

    Heat waves and the consequent heat stress of urban populations have a growing relevance in urban risk management and strategies of urban adaptation to climate change. In this context, social science studies on subjective experiencing of heat as stress by urban citizens are a new emerging field. To contribute to the understanding of self-reported subjective heat stress and its major determinants in a daily life perspective, we conducted a questionnaire survey with 323 respondents in Karlsruhe, Germany, after heat waves in July and August 2013. Statistical data analysis showed that subjective heat stress is an issue permeating everyday activities. Subjective heat stress at home was lower than at work and in general. Subjective heat stress in general, at home, and at work was determined by the health impairments experienced during the heat and the feeling of being helplessly exposed to the heat. For subjective heat stress at home, characteristics of the residential building and the built environment additionally played a role. Although the rate of implemented coping measures was rather high, coping measures showed no uniform effect for the subjective heat stress. We conclude that in terms of urban adaptation strategies, further research is needed to understand how various processes of daily social (work) life enable or limit individual coping and that communication strategies are important for building capacities to better cope with future heat waves.

  10. 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.

  11. Subjective stress factors in centrifuge training for military aircrews.

    Science.gov (United States)

    Lin, Pei-Chun; Wang, Jenhung; Li, Shih-Chin

    2012-07-01

    This study investigates stress-influence factors perceived by military aircrews undergoing centrifuge training, which lowers the incidence of G-induced loss of consciousness (G-LOC) for the crews of high-performance combat aircrafts. We used questionnaires to assess the subjective stress-influence factors of crews undergoing centrifuge training. Professionals in aviation physiology identified attributes measuring the perceived stress induced by centrifuge training, which were segmented into three constructs by factor analysis, theory lecture, centrifuge equipment, and physical fitness. Considerable interpenetration was discernible between these factors and military rank, age, length of service, flight hours accrued, and type of aircraft piloted. Identifying and quantifying the perceived stressors experienced in human-use centrifuge training enables aviators, astronauts, and air forces of the world to determine which constructs perceptibly increase or alleviate the perceived stress undergone by trainees when partaking in centrifuge training. Copyright © 2011 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  12. Serum prolidase enzyme activity in obese subjects and its relationship with oxidative stress markers.

    Science.gov (United States)

    Aslan, Mehmet; Duzenli, Ufuk; Esen, Ramazan; Soyoral, Yasemin Usul

    2017-10-01

    The relationship between increased serum enzyme activity of prolidase and increased rate of collagen turnover in the arterial wall has been asserted in previous studies. Collagen reflects much of the strength to the connective tissue involved in the arterial wall. Atherosclerosis is very common vessel disease and oxidative stress plays a pivotal role in the etiopathogenesis. Our objective was to examine the serum enzyme activity of prolidase and its possible relationships with oxidative stress parameters in obese subjects. Our present study was conducted 27 obese subjects and 26 age-matched healthy control subjects. The serum enzyme activity of prolidase in all study population was evaluated spectrophotometrically. Oxidative stress levels in obese subjects were analyzed with total antioxidant capacity (TAC) and total oxidant status (TOS) as well as oxidative stress index (OSI). Obese subjects have higher serum TOS and OSI indicators as well as prolidase activity than those in control subjects (for all; pstress levels in obese subjects. The significantly correlation between increased oxidative stress and increased prolidase activity may play a pivotal role in etiopathogenesis of atherosclerotic cardiovascular diseases in obese subjects. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. PERSONALITY AS SUBJECT OF THE RELATION TO THE STRESS

    Directory of Open Access Journals (Sweden)

    Milena Aleksandrovna Klenova

    2015-08-01

    Full Text Available In this scientific article results of the empirical research devoted to studying of the personality as the subject of the relation to a stress are presented. The understanding of a phenomenon of a stress not only taking into account social and psychological features of the personality, but also with inclusion of such category as representations of a stress and the relation towards him for the first time is considered by authors. In empirical research it is established that there are five types of the personality, as subjects of the relation to a stress according to their social and psychological features and ideas of a stress. «Destructive persons» – differ in the reduced level of social and psychological adaptation, they are motivated on failure, and the stress is perceived by them as emotional excitement. «Constructive persons» possess the high level of social and psychological adaptation, are focused on success, for them emotional burning out isn’t characteristic, and their representations and the relation to a stress is based on acceptance of existence of eustressor. «Emotional and intense persons» differ in uneasiness, high level of emotional burning out, and their ideas of a stress are based only on negative characteristics. «Sensitive persons» are characterized by the high level of sensitivity, and their relation to a stress can be defined as «mental anguish». For «rational persons» cognitive approach to a situation of a stress and idea of it as about response of an organism to negative emotions is peculiar. Thus, this scientific article represents results of original research of the personality from a position of its relation to a stress.Purpose: to study social and psychological features of the personality with inclusion of such category as «representations and the relation to a stress».Method or methodology of research it is based on the concept of social representations of S.Moskovichi, and also on the subject

  14. Self-stimulating rats combine subjective reward magnitude and subjective reward rate multiplicatively.

    Science.gov (United States)

    Leon, M I; Gallistel, C R

    1998-07-01

    For rats that bar pressed for intracranial electrical stimulation in a 2-lever matching paradigm with concurrent variable interval schedules of reward, the authors found that the time allocation ratio is based on a multiplicative combination of the ratio of subjective reward magnitudes and the ratio of the rates of reward. Multiplicative combining was observed in a range covering approximately 2 orders of magnitude in the ratio of the rates of reward from about 1:10 to 10:1) and an order of magnitude change in the size of rewards. After determining the relation between the pulse frequency of stimulation and subjective reward magnitude, the authors were able to predict from knowledge of the subjective magnitudes of the rewards and the obtained relative rates of reward the subject's time allocation ratio over a range in which it varied by more than 3 orders of magnitude.

  15. Intensity modulation of cutaneous electrical stimulation: : EPs and subjective ratings

    NARCIS (Netherlands)

    van der Heide, E.M.; Buitenweg, Jan R.; Marani, Enrico; Rutten, Wim

    2006-01-01

    Chronic pain research is increasingly focused on the neuroplastic mechanisms underlying subjective pain experience. The latter is often measured using reported pain intensity, e.g. using a numeric rating scale (NRS). Evoked Potentials (EPs) reflect the cortical representation of applied stimuli and

  16. Prediction of subjective ratings of emotional pictures by EEG features

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    McFarland, Dennis J.; Parvaz, Muhammad A.; Sarnacki, William A.; Goldstein, Rita Z.; Wolpaw, Jonathan R.

    2017-02-01

    Objective. Emotion dysregulation is an important aspect of many psychiatric disorders. Brain-computer interface (BCI) technology could be a powerful new approach to facilitating therapeutic self-regulation of emotions. One possible BCI method would be to provide stimulus-specific feedback based on subject-specific electroencephalographic (EEG) responses to emotion-eliciting stimuli. Approach. To assess the feasibility of this approach, we studied the relationships between emotional valence/arousal and three EEG features: amplitude of alpha activity over frontal cortex; amplitude of theta activity over frontal midline cortex; and the late positive potential over central and posterior mid-line areas. For each feature, we evaluated its ability to predict emotional valence/arousal on both an individual and a group basis. Twenty healthy participants (9 men, 11 women; ages 22-68) rated each of 192 pictures from the IAPS collection in terms of valence and arousal twice (96 pictures on each of 4 d over 2 weeks). EEG was collected simultaneously and used to develop models based on canonical correlation to predict subject-specific single-trial ratings. Separate models were evaluated for the three EEG features: frontal alpha activity; frontal midline theta; and the late positive potential. In each case, these features were used to simultaneously predict both the normed ratings and the subject-specific ratings. Main results. Models using each of the three EEG features with data from individual subjects were generally successful at predicting subjective ratings on training data, but generalization to test data was less successful. Sparse models performed better than models without regularization. Significance. The results suggest that the frontal midline theta is a better candidate than frontal alpha activity or the late positive potential for use in a BCI-based paradigm designed to modify emotional reactions.

  17. Heart rate variability (HRV): an indicator of stress

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    Kaur, Balvinder; Durek, Joseph J.; O'Kane, Barbara L.; Tran, Nhien; Moses, Sophia; Luthra, Megha; Ikonomidou, Vasiliki N.

    2014-05-01

    Heart rate variability (HRV) can be an important indicator of several conditions that affect the autonomic nervous system, including traumatic brain injury, post-traumatic stress disorder and peripheral neuropathy [3], [4], [10] & [11]. Recent work has shown that some of the HRV features can potentially be used for distinguishing a subject's normal mental state from a stressed one [4], [13] & [14]. In all of these past works, although processing is done in both frequency and time domains, few classification algorithms have been explored for classifying normal from stressed RRintervals. In this paper we used 30 s intervals from the Electrocardiogram (ECG) time series collected during normal and stressed conditions, produced by means of a modified version of the Trier social stress test, to compute HRV-driven features and subsequently applied a set of classification algorithms to distinguish stressed from normal conditions. To classify RR-intervals, we explored classification algorithms that are commonly used for medical applications, namely 1) logistic regression (LR) [16] and 2) linear discriminant analysis (LDA) [6]. Classification performance for various levels of stress over the entire test was quantified using precision, accuracy, sensitivity and specificity measures. Results from both classifiers were then compared to find an optimal classifier and HRV features for stress detection. This work, performed under an IRB-approved protocol, not only provides a method for developing models and classifiers based on human data, but also provides a foundation for a stress indicator tool based on HRV. Further, these classification tools will not only benefit many civilian applications for detecting stress, but also security and military applications for screening such as: border patrol, stress detection for deception [3],[17], and wounded-warrior triage [12].

  18. Overprotective social support leads to increased cardiovascular and subjective stress reactivity.

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    Zniva, Richard; Pauli, Paul; Schulz, Stefan M

    2017-02-01

    Self-determination theory suggests that autonomy-enhancing social support helps individuals to perceive stressors as challenging rather than stressing. Overprotective support may reduce stress in the short-run but undermines autonomy, thus hampering stress-coping in the long run, particularly when social support is terminated. Heartrate, blood-pressure and ratings were examined in N=44 undergraduate students receiving autonomy support (calculation steps) or overprotection (solutions) from a close friend or no support for solving arithmetic tasks as well as during a subsequent stress-challenge (solving arithmetic tasks alone). Overprotection resulted in increased heartrate, diastolic blood-pressure, stress ratings, and decreased subjective control during stress-challenge. Autonomy support did not lead to unfavorable stress responding. The current findings are in line with assumptions derived from self-determination theory and indicate that autonomy support can help to prevent stress. Overprotection does not buffer stress and is associated with increased stress when discontinued. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Age, subjective stress, and depression after ischemic stroke.

    Science.gov (United States)

    McCarthy, Michael J; Sucharew, Heidi J; Alwell, Kathleen; Moomaw, Charles J; Woo, Daniel; Flaherty, Matthew L; Khatri, Pooja; Ferioli, Simona; Adeoye, Opeolu; Kleindorfer, Dawn O; Kissela, Brett M

    2016-02-01

    The incidence of stroke among younger adults in the United States is increasing. Few studies have investigated the prevalence of depressive symptoms after stroke among different age groups or the extent to which subjective stress at the time of stroke interacts with age to contribute to post-stroke depression. The present study examined whether there exists an age gradient in survivors' level of depressive symptoms and explored the extent to which financial, family, and health-related stress may also impact on depression. Bivariate analyses (N = 322) indicated significant differences in depression and stress by age group, as well as differences in age and stress by 3-month depression status. Linear regression analyses indicated that survivors between the ages of 25-54 and 55-64 years old had, on average, significantly higher depressive symptom scores. Those with financial, family, and health-related stress at the time of stroke, irrespective of age, also had significantly higher scores.

  20. Dynamics of a seismogenic fault subject to variable strain rate

    OpenAIRE

    M. Dragoni; A. Piombo

    2011-01-01

    The behaviour of seismogenic faults is generally investigated under the assumption that they are subject to a constant strain rate. We consider the effect of a slowly variable strain rate on the recurrence times of earthquakes generated by a single fault. To this aim a spring-block system is employed as a low-order analog of the fault. Two cases are considered: a sinusoidal oscillation in the driver velocity and a monotonic change from one velocity value to another. In the f...

  1. Method for measuring biaxial stress in a body subjected to stress inducing loads

    Science.gov (United States)

    Clotfelter, W. N. (Inventor)

    1977-01-01

    A method is described for measuring stress in test articles including the steps of obtaining for a calibrating specimen a series of transit time differentials between the second wave echo for a longitudinal wave and the first wave echo for each of a pair of shear waves propagated through the specimen as it is subjected to known stress load of a series of stress loads for thus establishing a series of indications of the magnitudes for stress loads induced in the specimen, and thereafter obtaining a transit time differential between the second wave echo for a longitudinal wave and the first wave echo for each of a pair of shear waves propagated in the planes of the stress axes of a test article and comparing the transit time differential thus obtained to the series of transit time differentials obtained for the specimen to determine the magnitude of biaxial stress in the test article.

  2. Stiffness Evolution in Frozen Sands Subjected to Stress Changes

    KAUST Repository

    Dai, Sheng; Santamarina, Carlos

    2017-01-01

    Sampling affects all soils, including frozen soils and hydrate-bearing sediments. The authors monitor the stiffness evolution of frozen sands subjected to various temperature and stress conditions using an oedometer cell instrumented with P-wave transducers. Experimental results show the stress-dependent stiffness of freshly remolded sands, the dominant stiffening effect of ice, creep after unloading, and the associated exponential decrease in stiffness with time. The characteristic time for stiffness loss during creep is of the order of tens of minutes; therefore it is inevitable that frozen soils experience sampling disturbances attributable to unloading. Slow unloading minimizes stiffness loss; conversely, fast unloading causes a pronounced reduction in stiffness probably attributable to the brittle failure of ice or ice-mineral bonding.

  3. Stiffness Evolution in Frozen Sands Subjected to Stress Changes

    KAUST Repository

    Dai, Sheng

    2017-04-21

    Sampling affects all soils, including frozen soils and hydrate-bearing sediments. The authors monitor the stiffness evolution of frozen sands subjected to various temperature and stress conditions using an oedometer cell instrumented with P-wave transducers. Experimental results show the stress-dependent stiffness of freshly remolded sands, the dominant stiffening effect of ice, creep after unloading, and the associated exponential decrease in stiffness with time. The characteristic time for stiffness loss during creep is of the order of tens of minutes; therefore it is inevitable that frozen soils experience sampling disturbances attributable to unloading. Slow unloading minimizes stiffness loss; conversely, fast unloading causes a pronounced reduction in stiffness probably attributable to the brittle failure of ice or ice-mineral bonding.

  4. Aerobic exercise modulation of mental stress-induced responses in cultured endothelial progenitor cells from healthy and metabolic syndrome subjects.

    Science.gov (United States)

    Rocha, Natalia G; Sales, Allan R K; Miranda, Renan L; Silva, Mayra S; Silva, Jemima F R; Silva, Bruno M; Santos, Aline A; Nóbrega, Antonio C L

    2015-02-15

    Numerous studies have demonstrated that exercise acutely prevents the reduction in flow-mediated dilation induced by mental stress in subjects with metabolic syndrome (MetS). However, it is unknown whether a similar effect occurs in endothelial progenitors cells (EPCs). This study investigated whether exercise protects from the deleterious effect of mental stress on cultured EPCs in healthy subjects and those with MetS. Ten healthy subjects (aged 31±2) and ten subjects with MetS (aged 36±2) were enrolled. Subjects underwent a mental stress test, followed immediately by either 40 min of leg cycling or rest across two randomized sessions: mental stress+non-exercise control (MS) and mental stress+exercise (MS+EXE). The Stroop Color-Word Test was used to elicit mental stress. Blood samples were drawn at baseline and following sessions to isolate mononuclear cells. These cells were cultured in fibronectin-coated plates for seven days, and EPCs were identified by immunofluorescence (acLDL(+)/ UEA-I Lectin(+)). All subjects presented similar increases in mean blood pressure and heart rate during the mental stress test (P0.05). The EPC response to MS and MS+EXE was increased in healthy subjects, whereas it was decreased in subjects with MetS (Pexercise session increased EPCs in healthy subjects but did not prevent the EPC reduction induced by mental stress among subjects with MetS. © 2015.

  5. Entropy Analysis of RR and QT Interval Variability during Orthostatic and Mental Stress in Healthy Subjects

    Directory of Open Access Journals (Sweden)

    Mathias Baumert

    2014-12-01

    Full Text Available Autonomic activity affects beat-to-beat variability of heart rate and QT interval. The aim of this study was to explore whether entropy measures are suitable to detect changes in neural outflow to the heart elicited by two different stress paradigms. We recorded short-term ECG in 11 normal subjects during an experimental protocol that involved head-up tilt and mental arithmetic stress and computed sample entropy, cross-sample entropy and causal interactions based on conditional entropy from RR and QT interval time series. Head-up tilt resulted in a significant reduction in sample entropy of RR intervals and cross-sample entropy, while mental arithmetic stress resulted in a significant reduction in coupling directed from RR to QT. In conclusion, measures of entropy are suitable to detect changes in neural outflow to the heart and decoupling of repolarisation variability from heart rate variability elicited by orthostatic or mental arithmetic stress.

  6. Socioeconomic Status, Subjective Social Status, and Perceived Stress: Associations with Stress Physiology and Executive Functioning.

    Science.gov (United States)

    Ursache, Alexandra; Noble, Kimberly G; Blair, Clancy

    2015-01-01

    Several studies have investigated associations between socioeconomic status (SES) and indicators of children's physiological and cognitive self-regulation. Although objective measures of family SES may be good proxies for families' experiences of disadvantage, less is known about subjective aspects of families' experiences. We hypothesize that subjective social status (SSS) and perceived stress may be important independent predictors of children's stress physiology and executive functioning (EF). Eighty-two children from diverse SES backgrounds were administered EF measures and provided saliva samples for cortisol assay. Caregivers reported on objective SES, SSS, and perceived stress. Results suggest that SES and SSS are both independently and positively related to EF. In models predicting stress physiology, higher perceived stress was associated with lower baseline cortisol. Moreover, SES and age interacted to predict cortisol levels such that among younger children, lower SES was associated with higher cortisol, whereas among older children, lower SES was associated with lower cortisol. Results highlight the importance of considering both objective and subjective indicators of families' SES and stressful experiences in relation to multiple aspects of children's self-regulation.

  7. Sex differences in cardiovascular and subjective stress reactions: prospective evidence in a realistic military setting.

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    Taylor, Marcus K; Larson, Gerald E; Hiller Lauby, Melissa D; Padilla, Genieleah A; Wilson, Ingrid E; Schmied, Emily A; Highfill-McRoy, Robyn M; Morgan, Charles A

    2014-01-01

    Evidence points to heightened physiological arousal in response to acute stress exposure as both a prospective indicator and a core characteristic of posttraumatic stress disorder (PTSD). Because females may be at higher risk for PTSD development, it is important to evaluate sex differences in acute stress reactions. This study characterized sex differences in cardiovascular and subjective stress reactions among military survival trainees. One hundred and eighty-five military members (78% males) were studied before, during, and 24 h after stressful mock captivity. Cardiovascular (heart rate [HR], systolic blood pressure [SBP], diastolic blood pressure [DBP]) and dissociative states were measured at all three time points. Psychological impact of mock captivity was assessed during recovery. General linear modeling with repeated measures evaluated sex differences for each cardiovascular endpoint, and causal steps modeling was used to explore interrelationships among sex, cardiovascular reactions and psychological impact of mock captivity. Although females had lower SBP than males at all three time points, the difference was most pronounced at baseline and during stress. Accordingly, females showed greater residual elevation in SBP during recovery. Females had lower DBP at all three time points. In addition, females reported greater psychological impact of mock captivity than males. Exploratory causal steps modeling suggested that stress-induced HR may partially mediate the effect of sex on psychological impact of mock captivity. In conclusion, this study demonstrated sex-specific cardiovascular stress reactions in military personnel, along with greater psychological impact of stress exposure in females. This research may elucidate sex differences in PTSD development.

  8. Rate of injury and subjective benefits of gravitational wellness weightlifting.

    Science.gov (United States)

    Burke, David T; Bell, Regina; Al-Adawi, Samir; Alexandroni, Ariel; Dorvlo, Atsu; Burke, Daniel P

    2014-01-01

    A preliminary study using the "gravitational wellness" weightlifting technique demonstrated this to be a unique technique for loading the musculoskeletal system with extremely high loads over short arcs. This leads to rapid weekly strength gains using 30-minute weekly training sessions. This study was designed to further assess the benefit-risk ratio of the gravitational wellness weightlifting technique. This descriptive/retrospective study examined musculoskeletal and well-being outcomes as well as injuries reported by consecutive participants at one gravitational wellness gym. All adults presenting for training at the Atlanta, Georgia, gravitational wellness system facility over a 6-month period were invited to participate. Data were obtained by telephone interview concerning the presenting complaint/objective of training, subjective outcome, weights lifted, and injuries incurred during training. Of the 77 participants contacted via telephone, 92% agreed to participate (male, n=40; female, n=31). The participants ranged in age from 18 years to 69 years, with a mean age of 48.6 years. Of these, 42 (59%) presented to the gym with the objective of improving a defined musculoskeletal issue. The modal of these was chronic low-back pain. The subjects realized improvement on a 5-point Likert scale of 4.2/5 for their presenting complaint, and improved by 4.27/5 in their overall subjective health. There were no injuries. This study of consecutive participants at a gravitational wellness gym found that by lifting large weights over short arcs 3 0 minutes per week, participants significantly increased their strength, reduced their musculoskeletal pain, improve their subjective well-being, and reported a low rate of injury.

  9. The reaction to social stress in social phobia: discordance between physiological and subjective parameters.

    Science.gov (United States)

    Klumbies, Elisabeth; Braeuer, David; Hoyer, Juergen; Kirschbaum, Clemens

    2014-01-01

    Research on the biopsychological background of social phobia (SP) is scarce and inconsistent. We investigated endocrine and autonomic markers along with subjective responses to a standardized stress situation (Trier Social Stress Test, TSST) in SP patients and healthy controls (HC). We examined 88 patients with the primary diagnosis of SP as well as 78 age and sex comparable HCs with the TSST. Blood and saliva samples were obtained before and after the TSST for the assessment of salivary cortisol, plasma cortisol, salivary alpha-amylase (sAA), and prolactin. Heart rate (HR) and heart rate variability (HRV) were recorded continuously. Scalp-near hair samples were collected for the assessment of long-term cortisol secretion. The self-reported stress response was measured with different state and trait scales. While self-reported anxiety was elevated in SP before, during, immediately after, and one week after the TSST, no significant differences in biological stress responses were observed between SP and HC. There was a trend for SP to show higher baseline stress markers. Also long-term cortisol deposition in hair remained unaltered. Our results suggest that the excessive self-reported stress in SP is not reflected by a respective biological stress response. Patients with SP apparently show neither an extreme form of focused fear reactivity nor excessive defensive impairment.

  10. Dynamic energy release rate in couple-stress elasticity

    International Nuclear Information System (INIS)

    Morini, L; Piccolroaz, A; Mishuris, G

    2013-01-01

    This paper is concerned with energy release rate for dynamic steady state crack problems in elastic materials with microstructures. A Mode III semi-infinite crack subject to loading applied on the crack surfaces is considered. The micropolar behaviour of the material is described by the theory of couple-stress elasticity developed by Koiter. A general expression for the dynamic J-integral including both traslational and micro-rotational inertial contributions is derived, and the conservation of this integral on a path surrounding the crack tip is demonstrated

  11. Rate of injury and subjective benefits of gravitational wellness weightlifting

    Directory of Open Access Journals (Sweden)

    Burke DT

    2014-09-01

    wellness gym found that by lifting large weights over short arcs 30 minutes per week, participants significantly increased their strength, reduced their musculoskeletal pain, improve their subjective well-being, and reported a low rate of injury. Keywords: gravitational wellness system, rate of injuries, weight training, descriptive study

  12. [Subjective and objective indicators of job stress and burnout in a residential home for the elderly].

    Science.gov (United States)

    Fiabane, Elena; Dordoni, Paola; Argentero, Piergiorgio

    2016-01-01

    Elderly care workers have a higher risk than other professionals of developing burnout. Despite literature has highlighted the methodological advantage resulting from an integration of subjective and objective measures of stressors, only few studies have investigated job stress and burnout in the Italian elderly care context using this kind of assessment. The aims of this study were: (a) to investigate the level of stress and burnout and their organizational sources in a sample of eldercare workers by means of subjective and objective tools, and b) to compare the stress and burnout levels between health care staff and nursing aides employed in a residential home for the, elderly. The sample of the study included the totality of the elderly workers employed in a residential home for the elderly (N=49; response rate: 100%). The Maslach Burnout Inventory-GS and the Areas of Worklife Scale were used for the subjective assessment of burnout and organizational riskfactors. A check list of objective indicators was used for the objective assessment of job stress. Results from the self-report questionnaires showed high levels of exhaustion and a perception of high workload and unfairness for, the total sample. Objective parameters ofjob stress risk were biomechanical overload, dealing with suffering people and the risk of work-related violence. Nursing aides had greater risk of burnout and reported a greater number of objective sources of stress, compared to health care workers. This exploratory study supports the use of both subjective and objective method for the assessment of job stress risk as the most comprehensive approach for the implementation of preventive and corrective interventions.

  13. Oxidative stress and inflammation in renal patients and healthy subjects.

    Directory of Open Access Journals (Sweden)

    Diana M Lee

    Full Text Available The first goal of this study was to measure the oxidative stress (OS and relate it to lipoprotein variables in 35 renal patients before dialysis (CKD, 37 on hemodialysis (HD and 63 healthy subjects. The method for OS was based on the ratio of cholesteryl esters (CE containing C18/C16 fatty acids (R2 measured by gas chromatography (GC which is a simple, direct, rapid and reliable procedure. The second goal was to investigate and identify a triacylglycerol peak on GC, referred to as TG48 (48 represents the sum of the three fatty acids carbon chain lengths which was markedly increased in renal patients compared to healthy controls. We measured TG48 in patients and controls. Mass spectrometry (MS and MS twice in tandem were used to analyze the fatty acid composition of TG48. MS showed that TG48 was abundant in saturated fatty acids (SFAs that were known for their pro-inflammatory property. TG48 was significantly and inversely correlated with OS. Renal patients were characterized by higher OS and inflammation than healthy subjects. Inflammation correlated strongly with TG, VLDL-cholesterol, apolipoprotein (apo C-III and apoC-III bound to apoB-containing lipoproteins, but not with either total cholesterol or LDL-cholesterol.In conclusion, we have discovered a new inflammatory factor, TG48. It is characterized with TG rich in saturated fatty acids. Renal patients have increased TG48 than healthy controls.

  14. Subjective stress reactivity in psoriasis - a cross sectional study of associated psychological traits.

    Science.gov (United States)

    Remröd, Charlotta; Sjöström, Karin; Svensson, Åke

    2015-05-02

    Stress or psychological distress is often described as a causative or maintaining factor in psoriasis. Psychological traits may influence the appraisal, interpretation and coping ability regarding stressful situations. Detailed investigations of psychological traits in relation to stress reactivity in psoriasis are rare. The aim of this study was to examine whether patients with psoriasis who report an association between psychological distress and exacerbation, "stress reactors" (SRs), differ psychologically from those with no stress reactivity "non-stress reactors" (NSRs). This cross-sectional study was conducted among 101 consecutively recruited outpatients with plaque psoriasis. A psychosocial interview was performed including questions concerning stress reactivity in relation to onset and exacerbation. Three validated self-rating scales were used: Spielberger State-Trait Anxiety Inventory (STAI, Form-Y), Beck Depression Inventory (BDI-II) and Swedish Universities Scales of Personality (SSP). Independent samples t-tests, Chi-square tests and one-way ANOVA analyses were used for group comparisons when appropriate. A logistic regression model was designed with SR as the dependent variable. Sixty-four patients (63%) reported a subjective association between disease exacerbation and stress (SRs). Patients defined as SRs reported significantly higher mean scores regarding state and trait anxiety, depression, and also five SSP scale personality traits, i.e. somatic trait anxiety, psychic trait anxiety, stress susceptibility, lack of assertiveness and mistrust, compared with NSRs. In multivariate analysis, SSP-stress susceptibility was the strongest explanatory variable for SR, i.e. OR (95% CI)=1.13 (1.02 - 1.24), p=0.018. According to our results, patients who perceive stress as a causal factor in their psoriasis might have a more vulnerable psychological constitution. This finding suggests important opportunities for clinicians to identify patients who may benefit

  15. High Strain Rate Response of 7055 Aluminum Alloy Subject to Square-spot Laser Shock Peening

    Science.gov (United States)

    Sun, Rujian; Zhu, Ying; Li, Liuhe; Guo, Wei; Peng, Peng

    2017-12-01

    The influences of laser pulse energy and impact time on high strain rate response of 7055 aluminum alloy subject to square-spot laser shock peening (SLSP) were investigate. Microstructural evolution was characterized by OM, SEM and TEM. Microhardness distribution and in-depth residual stress in 15 J with one and two impacts and 25 J with one and two impacts were analyzed. Results show that the original rolling structures were significantly refined due to laser shock induced recrystallization. High density of microdefects was generated, such as dislocation tangles, dislocation wall and stacking faults. Subgrains and nanograins were induced in the surface layer, resulting in grain refinement in the near surface layer after SLSP. Compressive residual stresses with maximum value of more than -200 MPa and affected depths of more than 1 mm can be generated after SLSP. Impact time has more effectiveness than laser pulse energy in increasing the magnitude of residual stress and achieving thicker hardening layer.

  16. Oxidative stress in hepatitis C infected end-stage renal disease subjects

    OpenAIRE

    Koylu Ahmet O; Aslan Mehmet; Bolukbas Filiz F; Bolukbas Cengiz; Horoz Mehmet; Selek Sahbettin; Erel Ozcan

    2006-01-01

    Abstract Background Both uremia and hepatitis C infection is associated with increased oxidative stress. In the present study, we aimed to find out whether hepatitis C infection has any impact on oxidative stress in hemodialysis subjects. Methods Sixteen hepatitis C (+) hemodialysis subjects, 24 hepatitis C negative hemodialysis subjects and 24 healthy subjects were included. Total antioxidant capacity, total peroxide level and oxidative stress index were determined in all subjects. Results T...

  17. A closed-loop hybrid physiological model relating to subjects under physical stress.

    Science.gov (United States)

    El-Samahy, Emad; Mahfouf, Mahdi; Linkens, Derek A

    2006-11-01

    The objective of this research study is to derive a comprehensive physiological model relating to subjects under physical stress conditions. The model should describe the behaviour of the cardiovascular system, respiratory system, thermoregulation and brain activity in response to physical workload. An experimental testing rig was built which consists of recumbent high performance bicycle for inducing the physical load and a data acquisition system comprising monitors and PCs. The signals acquired and used within this study are the blood pressure, heart rate, respiration, body temperature, and EEG signals. The proposed model is based on a grey-box based modelling approach which was used because of the sufficient level of details it provides. Cardiovascular and EEG Data relating to 16 healthy subject volunteers (data from 12 subjects were used for training/validation and the data from 4 subjects were used for model testing) were collected using the Finapres and the ProComp+ monitors. For model validation, residual analysis via the computing of the confidence intervals as well as related histograms was performed. Closed-loop simulations for different subjects showed that the model can provide reliable predictions for heart rate, blood pressure, body temperature, respiration, and the EEG signals. These findings were also reinforced by the residual analyses data obtained, which suggested that the residuals were within the 90% confidence bands and that the corresponding histograms were of a normal distribution. A higher intelligent level was added to the model, based on neural networks, to extend the capabilities of the model to predict over a wide range of subjects dynamics. The elicited physiological model describing the effect of physiological stress on several physiological variables can be used to predict performance breakdown of operators in critical environments. Such a model architecture lends itself naturally to exploitation via feedback control in a 'reverse

  18. Presence of a dog reduces subjective but not physiological stress responses to an analog trauma.

    Science.gov (United States)

    Lass-Hennemann, Johanna; Peyk, Peter; Streb, Markus; Holz, Elena; Michael, Tanja

    2014-01-01

    Dogs are known to have stress and anxiety reducing effects. Several studies have shown that dogs are able to calm people during cognitive and performance stressors. Recently, therapy dogs have been proposed as a treatment adjunct for post-traumatic stress disorder patients. In this study we aimed to investigate, whether dogs also have anxiety- and stress reducing effect during "traumatic stressors." 80 healthy female participants were randomly assigned to one of four conditions. They were exposed to a "traumatic" film clip (trauma-film-paradigm). For one group of participants a friendly dog was present during the film, one group of participants was accompanied by a friendly human, another control group watched the film with a toy animal and the last group watched the film clip alone. Participants that were accompanied by the dog during the film reported lower anxiety ratings and less negative affect after the film clip as compared to the "toy dog group" and the "alone group." Results of the "dog group" were comparable to the group that was accompanied by a friendly human. There were no differences in physiological stress responses between the four conditions. Our results show that dogs are able to lessen subjectively experienced stress and anxiety during a "traumatic" stress situation. This effect was comparable to that of social support by a friendly person. Implications for PTSD patients are discussed.

  19. Effects of food on cortisol and mood in vulnerable subjects under controllable and uncontrollable stress

    NARCIS (Netherlands)

    Markus, R.; Panhuysen, G.; Tuiten, A.; Koppeschaar, H.

    2000-01-01

    The aim of this study was to investigate whether in stress-prone subjects, carbohydrate-rich, protein-poor food (CR/PP) diminished depressive mood and a cortisol response under controllable as well as uncontrollable laboratory stress. Twenty-two subjects with high stress proneness (HS) and 23

  20. Subjective health complaints, work-related stress and self-efficacy in Norwegian aircrew.

    Science.gov (United States)

    Omholt, M L; Tveito, T H; Ihlebæk, C

    2017-03-01

    The European civilian aviation industry has undergone major changes in the last decade. Despite this, there is little knowledge about work-related stress and subjective health complaints (SHCs) affecting Norwegian aircrew. To investigate the relationships between work-related stress, self-efficacy and SHCs in commercial aircrew in Norway and to explore differences between cockpit and cabin crew. Aircrew members from the three major airlines operating from Norway completed an electronically distributed questionnaire. Linear regression analyses were used to investigate the association between work-related stress, self-efficacy and SHCs. There was a 21% response rate. Among the 843 study subjects, tiredness, sleep problems, bloating, low back pain, headaches and neck pain were the most prevalent SHCs. Cabin crew reported significantly higher numbers, prevalences and mean values for all SHCs compared with cockpit crew (P stress levels. High levels of work-related stress were significantly associated with all SHC factors in both groups. Self-efficacy partly moderated the relationship between stress and psychological complaints in both cockpit and cabin crew, and for musculoskeletal complaints in cockpit crew. The model explained 23 and 32% of the variance in psychological complaints for cockpit and cabin crew, respectively. Commercial aircrew in Norway reported high numbers of SHCs, and high levels of work-related stress were associated with high numbers of SHC. More knowledge is needed on the physical, organizational and psychosocial stressors affecting cockpit and cabin crew in order to create a healthier work environment for these groups. © The Author 2016. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  1. Serum C-reactive protein and thioredoxin levels in subjects with mildly reduced glomerular filtration rate

    Directory of Open Access Journals (Sweden)

    Ishimura Eiji

    2010-04-01

    Full Text Available Abstract Background Chronic kidney disease (CKD is a newly recognized high-risk condition for cardiovascular disease (CVD, and previous studies reported the changes in inflammation and oxidative stress in advanced stages of CKD. We compared the levels of serum biomarkers for inflammation and oxidative stress between subjects with normal and mildly reduced glomerular filtration rate (GFR. Methods The subjects were 182 participants of a health check-up program including those with normal (≥ 90 mL/min/1.73 m2, N = 79 and mildly reduced eGFR (60-89 mL/min/1.73 m2, N = 103 which was calculated based on serum creatinine, age and sex. We excluded those with reduced eGFR 2. No one had proteinuria. We measured serum levels of C-reactive protein (CRP and thioredoxin (TRX as the markers of inflammation and oxidative stress, respectively. Results As compared with subjects with normal eGFR, those with mildly reduced eGFR had increased levels of both CRP and TRX. Also, eGFR was inversely correlated with these biomarkers. The associations of eGFR with these biomarkers remained significant after adjustment for age and sex. When adjustment was done for eight possible confounders, CRP showed significant association with systolic blood pressure, high density lipoprotein cholesterol (HDL-C and non-HDL-C, whereas TRX was associated with sex significantly, and with eGFR and systolic blood pressure at borderline significance. Conclusions We showed the increased levels of CRP and TRX in subjects with mildly reduced eGFR. The eGFR-CRP link and the eGFR-TRX link appeared to be mediated, at least partly, by the alterations in blood pressure and plasma lipids in these subjects.

  2. Oxidative stress in hepatitis C infected end-stage renal disease subjects

    Directory of Open Access Journals (Sweden)

    Koylu Ahmet O

    2006-07-01

    Full Text Available Abstract Background Both uremia and hepatitis C infection is associated with increased oxidative stress. In the present study, we aimed to find out whether hepatitis C infection has any impact on oxidative stress in hemodialysis subjects. Methods Sixteen hepatitis C (+ hemodialysis subjects, 24 hepatitis C negative hemodialysis subjects and 24 healthy subjects were included. Total antioxidant capacity, total peroxide level and oxidative stress index were determined in all subjects. Results Total antioxidant capacity was significantly higher in controls than hemodialysis subjects with or without hepatitis C infection (all p 0.05/3. Conclusion Oxidative stress is increased in both hepatitis C (+ and hepatitis C (- hemodialysis subjects. However, hepatitis C infection seems to not cause any additional increase in oxidative stress in hemodialysis subjects and it may be partly due to protective effect of dialysis treatment on hepatitis C infection.

  3. Rivulet flow round a horizontal cylinder subject to a uniform surface shear stress

    KAUST Repository

    Paterson, C.; Wilson, S. K.; Duffy, B. R.

    2014-01-01

    large stationary horizontal cylinder subject to a prescribed uniform azimuthal surface shear stress is investigated. In particular, we focus on the case where the volume flux is downwards but the shear stress is upwards, for which there is always a

  4. Intake, physiological parameters and behavior of Angus and Nellore bulls subjected to heat stress

    Directory of Open Access Journals (Sweden)

    Ériton Egidio Lisboa Valente

    2015-12-01

    Full Text Available Genetics differences between breeds may determine the tolerance to high temperature, effect dry matter intake and consequently cattle performance. The effect of temperature and humidity index (THI on diurnal, nocturnal and daily intake, water intake, physiologic parameters and behavior of Nellore (B. indicus and Angus (B. taurus bulls were evaluated. Eight Angus and eight Nellore young bulls (337±7.4 kg and 16 months of age were allocated in two climate-controlled rooms for 32 days. In the period 1, all bulls were housed in thermoneutral conditions (TN, THI = 72.6 for 10 days. In period 2 (10 days, four Angus and four Nellore bulls were subjected to low heat stress (LHS, THI = 76.4 in daytime, and four Angus and four Nellore bulls were subjected to high heat stress (HHS, THI = 81.5 in daytime. The diurnal and daily dry matter intake (DMI of Nellore were not affected (P>0.05 by heat stress. However, Angus bulls decreased diurnal DMI by 24% and daily DMI decreased (P<0.05 by 15% on HHS. In TN Angus bulls had higher (P<0.05 daily DMI (36.2 g/kg of BW than Nellore (29.1 g/kg of BW, but in HHS they had similar (P>0.05 daily DMI (31.6 and 30.2 g/kg of BW, respectively. We observed an increase (P<0.05 in respiratory frequency, but water intake was not affected (P>0.05 by heat stress. The heart rate decreased (P<0.05 with heat stress. No differences were found (P>0.05 in feeding behavior. Therefore, THI stress threshold should distinct for Angus and Nellore bulls. The use of feed intake information may improve the prediction of thermic discomfort on specific climate condition. 

  5. Presence of a dog reduces subjective but not physiological stress responses to an analogue trauma

    Directory of Open Access Journals (Sweden)

    Johanna eLass-Hennemann

    2014-09-01

    Full Text Available Dogs are known to have stress and anxiety reducing effects. Several studies have shown that dogs are able to calm people during cognitive and performance stressors. Recently, therapy dogs have been proposed as a treatment adjunct for PTSD patients. In this study we aimed to investigate, whether dogs also have anxiety- and stress reducing effect during traumatic stressors. 80 healthy female participants were randomly assigned to one of 4 conditions. They were exposed to a traumatic film clip (trauma-film-paradigm. For one group of participants a friendly dog was present during the film, one group of participants was accompanied by a friendly human, another control group watched the film with a toy animal and the last group watched the film clip alone. Participants that were accompanied by the dog during the film reported lower anxiety ratings and less negative affect after the film clip as compared to the toy dog group and the alone group. Results of the dog group were comparable to the group that was accompanied by a friendly human. There were no differences in physiological stress responses between the four conditions. Our results show that dogs are able to lessen subjectively experienced stress and anxiety during a traumatic stress situation. This effect was comparable to that of social support by a friendly person. Implications for PTSD patients are discussed.

  6. Increased strength of concrete subject to high loading rates

    International Nuclear Information System (INIS)

    Curbach, M.

    1987-01-01

    Within the scope of this work various problems are discussed which occur in connection with concrete under high tensile loading rates (e.g. when a plane crashes on a nuclear power plant very high loads occur which act only for a very short time). Particularly the causes for the already frequently noticed increases in strength with increasing loading rates are investigated and also the question whether this increased strength can be taken into account when dimensioning a construction. (MM) [de

  7. Oxidative stress in hepatitis C infected end-stage renal disease subjects.

    Science.gov (United States)

    Horoz, Mehmet; Bolukbas, Cengiz; Bolukbas, Filiz F; Aslan, Mehmet; Koylu, Ahmet O; Selek, Sahbettin; Erel, Ozcan

    2006-07-14

    Both uremia and hepatitis C infection is associated with increased oxidative stress. In the present study, we aimed to find out whether hepatitis C infection has any impact on oxidative stress in hemodialysis subjects. Sixteen hepatitis C (+) hemodialysis subjects, 24 hepatitis C negative hemodialysis subjects and 24 healthy subjects were included. Total antioxidant capacity, total peroxide level and oxidative stress index were determined in all subjects. Total antioxidant capacity was significantly higher in controls than hemodialysis subjects with or without hepatitis C infection (all p total peroxide level and oxidative stress index were significantly lower (all p total antioxidant capacity compared to hepatitis C (+) hemodialysis subjects (all p Total peroxide level and oxidative stress index was comparable between hemodialysis subjects with or without hepatitis C infection (p > 0.05/3). Oxidative stress is increased in both hepatitis C (+) and hepatitis C (-) hemodialysis subjects. However, hepatitis C infection seems to not cause any additional increase in oxidative stress in hemodialysis subjects and it may be partly due to protective effect of dialysis treatment on hepatitis C infection.

  8. A Computational Framework to Optimize Subject-Specific Hemodialysis Blood Flow Rate to Prevent Intimal Hyperplasia

    Science.gov (United States)

    Mahmoudzadeh, Javid; Wlodarczyk, Marta; Cassel, Kevin

    2017-11-01

    Development of excessive intimal hyperplasia (IH) in the cephalic vein of renal failure patients who receive chronic hemodialysis treatment results in vascular access failure and multiple treatment complications. Specifically, cephalic arch stenosis (CAS) is known to exacerbate hypertensive blood pressure, thrombosis, and subsequent cardiovascular incidents that would necessitate costly interventional procedures with low success rates. It has been hypothesized that excessive blood flow rate post access maturation which strongly violates the venous homeostasis is the main hemodynamic factor that orchestrates the onset and development of CAS. In this article, a computational framework based on a strong coupling of computational fluid dynamics (CFD) and shape optimization is proposed that aims to identify the effective blood flow rate on a patient-specific basis that avoids the onset of CAS while providing the adequate blood flow rate required to facilitate hemodialysis. This effective flow rate can be achieved through implementation of Miller's surgical banding method after the maturation of the arteriovenous fistula and is rooted in the relaxation of wall stresses back to a homeostatic target value. The results are indicative that this optimized hemodialysis blood flow rate is, in fact, a subject-specific value that can be assessed post vascular access maturation and prior to the initiation of chronic hemodialysis treatment as a mitigative action against CAS-related access failure. This computational technology can be employed for individualized dialysis treatment.

  9. Oxidative stress among subjects with metabolic syndrome in Sokoto ...

    African Journals Online (AJOL)

    2015-08-20

    Aug 20, 2015 ... Background: Oxidative stress is known to play a role in the ... others to remix, tweak, and build upon the work non-commercially, as long as the ..... Report of the National Heart, Lung, and Blood Institute/American Heart.

  10. Differentiation chronic post traumatic stress disorder patients from healthy subjects using objective and subjective sleep-related parameters.

    Science.gov (United States)

    Tahmasian, Masoud; Jamalabadi, Hamidreza; Abedini, Mina; Ghadami, Mohammad R; Sepehry, Amir A; Knight, David C; Khazaie, Habibolah

    2017-05-22

    Sleep disturbance is common in chronic post-traumatic stress disorder (PTSD). However, prior work has demonstrated that there are inconsistencies between subjective and objective assessments of sleep disturbance in PTSD. Therefore, we investigated whether subjective or objective sleep assessment has greater clinical utility to differentiate PTSD patients from healthy subjects. Further, we evaluated whether the combination of subjective and objective methods improves the accuracy of classification into patient versus healthy groups, which has important diagnostic implications. We recruited 32 chronic war-induced PTSD patients and 32 age- and gender-matched healthy subjects to participate in this study. Subjective (i.e. from three self-reported sleep questionnaires) and objective sleep-related data (i.e. from actigraphy scores) were collected from each participant. Subjective, objective, and combined (subjective and objective) sleep data were then analyzed using support vector machine classification. The classification accuracy, sensitivity, and specificity for subjective variables were 89.2%, 89.3%, and 89%, respectively. The classification accuracy, sensitivity, and specificity for objective variables were 65%, 62.3%, and 67.8%, respectively. The classification accuracy, sensitivity, and specificity for the aggregate variables (combination of subjective and objective variables) were 91.6%, 93.0%, and 90.3%, respectively. Our findings indicate that classification accuracy using subjective measurements is superior to objective measurements and the combination of both assessments appears to improve the classification accuracy for differentiating PTSD patients from healthy individuals. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    Sowa, Claudia J.; Lustman, Patrick J.

    1984-01-01

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

  12. The impact of food viscosity on eating rate, subjective appetite, glycemic response and gastric emptying rate.

    Directory of Open Access Journals (Sweden)

    Yong Zhu

    Full Text Available Understanding the impact of rheological properties of food on postprandial appetite and glycemic response helps to design novel functional products. It has been shown that solid foods have a stronger satiating effect than their liquid equivalent. However, whether a subtle change in viscosity of a semi-solid food would have a similar effect on appetite is unknown. Fifteen healthy males participated in the randomized cross-over study. Each participant consumed a 1690 kJ portion of a standard viscosity (SV and a high viscosity (HV semi-solid meal with 1000 mg acetaminophen in two separate sessions. At regular intervals during the three hours following the meal, subjective appetite ratings were measured and blood samples collected. The plasma samples were assayed for insulin, glucose-dependent insulinotropic peptide (GIP, glucose and acetaminophen. After three hours, the participants were provided with an ad libitum pasta meal. Compared with the SV meal, HV was consumed at a slower eating rate (P = 0.020, with postprandial hunger and desire to eat being lower (P = 0.019 and P<0.001 respectively while fullness was higher (P<0.001. In addition, consuming the HV resulted in lower plasma concentration of GIP (P<0.001, higher plasma concentration of glucose (P<0.001 and delayed gastric emptying as revealed by the acetaminophen absorption test (P<0.001. However, there was no effect of food viscosity on insulin or food intake at the subsequent meal. In conclusion, increasing the viscosity of a semi-solid food modulates glycemic response and suppresses postprandial satiety, although the effect may be short-lived. A slower eating rate and a delayed gastric emptying rate can partly explain for the stronger satiating properties of high viscous semi-solid foods.

  13. Effects of social stress on heart rate and heart rate variability in growing pigs

    NARCIS (Netherlands)

    Jong, de I.C.; Sgoifo, A.; Lambooij, E.; Korte, S.M.; Blokhuis, H.J.; Koolhaas, J.M.

    2000-01-01

    The effects of social stress on heart rate, heart rate variability and the occurrence of cardiac arrhythmias were studied in 12 growing pigs. Social stress was induced during a good competition test with a pen mate, and subsequently during a resident-intruder test with an unacquainted pig in which

  14. Effects of social stress on heart rate and heart rate variability in growing pigs

    NARCIS (Netherlands)

    de Jong, IC; Sgoifo, A; Lambooij, E; Korte, SM; Blokhuis, HJ; Koolhaas, JM

    The effects of social stress on heart rate, heart rate variability and the occurrence of cardiac arrhythmias were studied in 12 growing pigs. Social stress was induced during a good competition test with a pen mate, and subsequently during a resident-intruder test with an unacquainted pig in which

  15. Compatible solutes in lactic acid bacteria subjected to water stress

    NARCIS (Netherlands)

    Kets, E.P.W.

    1997-01-01

    The goal of the research project described in this thesis was to investigate the protective effect of compatible solutes on tactic acid bacteria subjected to drying. Dried preparations of lactic acid bacteria are applied as starter cultures in feed and food industries. Dried starter

  16. Evaluation of oxidative stress in mice subjected to aerobic exercise.

    Science.gov (United States)

    Lima, Mônica Cruvinel de; Marks, Guido; Silva, Iandara Schettert; Silva, Baldomero Antonio Kato da; Cônsolo, Lourdes Zélia Zanoni; Nogueira, Gabriel Bogalho

    2012-08-01

    To evaluate the influence of aerobic exercise on oxidative stress in mice. The study included twenty female mice Mus musculus-Swiss divided into two groups: sedentary control (GA) and exercise (GB), each containing ten animals. All animals underwent an adaptation period of seven days isolated in individual boxes. After this period, the animals in the exercise group (GB) were trained in angled running wheel with circumference of 25 cm assembled on an articulated axle during five minutes for three consecutive days. On the fourth day, they underwent an exercise program of one session lasting 45 minutes. The evaluation of oxidative stress was performed by determining the levels of malondialhyde derived of lipid peroxidation by the TBA method. The samples were read in a spectrophotometer at 535 nm. No significant difference was observed in the intergroup comparison of MDA levels in the tissues evaluated. A significant difference was observed in the intragroup comparison of MDA levels in the control group (p = 0.0201).The Tukeys' post hoc test indicated significantly lower values of MDA in the smooth muscle in relation to plasma. In the analysis of variance in the exercise group, a significant difference between tissues (p = 0.0009), with significantly lower values in the smooth muscle in relation to plasma (pstress in mice which were undergone a single session of aerobic exercise.

  17. Statistical damage constitutive model for rocks subjected to cyclic stress and cyclic temperature

    Science.gov (United States)

    Zhou, Shu-Wei; Xia, Cai-Chu; Zhao, Hai-Bin; Mei, Song-Hua; Zhou, Yu

    2017-10-01

    A constitutive model of rocks subjected to cyclic stress-temperature was proposed. Based on statistical damage theory, the damage constitutive model with Weibull distribution was extended. Influence of model parameters on the stress-strain curve for rock reloading after stress-temperature cycling was then discussed. The proposed model was initially validated by rock tests for cyclic stress-temperature and only cyclic stress. Finally, the total damage evolution induced by stress-temperature cycling and reloading after cycling was explored and discussed. The proposed constitutive model is reasonable and applicable, describing well the stress-strain relationship during stress-temperature cycles and providing a good fit to the test results. Elastic modulus in the reference state and the damage induced by cycling affect the shape of reloading stress-strain curve. Total damage induced by cycling and reloading after cycling exhibits three stages: initial slow increase, mid-term accelerated increase, and final slow increase.

  18. Normal stress databases in myocardial perfusion scintigraphy – how many subjects do you need?

    DEFF Research Database (Denmark)

    Trägårdh, Elin; Sjöstrand, Karl; Edenbrandt, Lars

    2012-01-01

    ) for male, NC for female, attenuation‐corrected images (AC) for male and AC for female subjects. 126 male and 205 female subjects were included. The normal database was created by alternatingly computing the mean of all normal subjects and normalizing the subjects with respect to this mean, until...... convergence. Coefficients of variation (CV) were created for increasing number of included patients in the four different normal stress databases. Normal stress databases with ...Commercial normal stress databases in myocardial perfusion scintigraphy (MPS) commonly consist of 30–40 individuals. The aim of the study was to determine how many subjects are needed. Four normal stress databases were developed using patients who underwent 99mTc MPS: non‐corrected images (NC...

  19. Salivary alpha amylase activity in human beings of different age groups subjected to psychological stress.

    Science.gov (United States)

    Sahu, Gopal K; Upadhyay, Seema; Panna, Shradha M

    2014-10-01

    Salivary alpha-amylase (sAA) has been proposed as a sensitive non-invasive biomarker for stress-induced changes in the body that reflect the activity of the sympathetic nervous system. Though several experiments have been conducted to determine the validity of this salivary component as a reliable stress marker in human subjects, the effect of stress induced changes on sAA level in different age groups is least studied. This article reports the activity of sAA in human subjects of different age groups subjected to psychological stress induced through stressful video clip. Differences in sAA level based on sex of different age groups under stress have also been studied. A total of 112 subjects consisting of both the male and female subjects, divided into two groups on basis of age were viewed a video clip of corneal transplant surgery as stressor. Activity of sAA from saliva samples of the stressed subjects were measured and compared with the activity of the samples collected from the subjects before viewing the clip. The age ranges of subjects were 18-25 and 40-60 years. The sAA level increased significantly in both the groups after viewing the stressful video. The increase was more pronounced in the younger subjects. The level of sAA was comparatively more in males than females in the respective groups. No significant change in sAA activity was observed after viewing the soothed video clip. Significant increase of sAA level in response to psychological stress suggests that it might act as a reliable sympathetic activity biochemical marker in different stages of human beings.

  20. High Strain Rate Deformation Mechanisms of Body Centered Cubic Material Subjected to Impact Loading

    Science.gov (United States)

    Visser, William

    Low carbon steel is the most common grade of structural steel used; it has carbon content of 0.05% to 0.25% and very low content of alloying elements. It is produced in great quantities and provides material properties that are acceptable for many engineering applications, particularly in the construction industry in which low carbon steel is widely used as the strengthening phase in civil structures. The overall goal of this dissertation was to investigate the deformation response of A572 grade 50 steel when subjected to impact loading. This steel has a 0.23% by weight carbon content and has less than 2% additional alloying elements. The deformation mechanisms of this steel under shock loading conditions include both dislocation motion and twin formation. The goal of this work was achieved by performing experimental, analytical and numerical research in three integrated tasks. The first is to determine the relationship between the evolution of deformation twins and the impact pressure. Secondly, a stress criterion for twin nucleation during high strain rate loading was developed which can account for the strain history or initial dislocation density. Lastly, a method was applied for separating the effects of dislocations and twins generated by shock loading in order to determine their role in controlling the flow stress of the material. In this regard, the contents of this work have been categorically organized. First, the active mechanisms in body centered cubic (BCC) low carbon steel during shock loading have been determined as being a composed of the competing mechanisms of dislocations and deformation twins. This has been determined through a series of shock loading tests of the as-received steel. The shock loading tests were done by plate impact experiments at several impact pressures ranging from 2GPa up to 13GPa using a single stage light gas gun. A relationship between twin volume fraction and impact pressure was determined and an analytical model was

  1. Reliability of mechanical components subjected to combined alternating and mean stresses with a nonconstant stress ratio

    International Nuclear Information System (INIS)

    Kececioglu, D.; Lamarre, G.B.

    1979-01-01

    The reliability of reactor mechanical components and structural members, submitted to external loads which induce alternating bending stresses and mean shear stresses at the critical section where failure has a high probability of occurring, is predicted assuming that the ratio of the distributed alternating stress to the mean stress is also distributed and yields a bivariate failure-governing, combined alternating and mean, stress distribution. A computer programmed methodology is developed to calculate the reliability under these conditions given the associated distributional Goodman diagram for a reactor component or structural member. (orig.)

  2. Evaluation of Stress Parameters Based on Heart Rate Variability Measurements

    OpenAIRE

    Uysal, Fatma; Tokmakçı, Mahmut

    2018-01-01

    In this study, heart rate variabilitymeasurements and analysis was carried with help of the ECG recordings to showhow autonom nervous system activity changes. So as to evaluate the parametersrelated to stress of the study, the situation of relaxation, Stroop color/wordtest, mental test and auditory stimulus that would stress someone out wereapplied to six volunteer participants in a laboratory environment. Being takentotally seven minutes ECG recording and made analysis in time and frequencyd...

  3. Drought stress had a predominant effect over heat stress on three tomato cultivars subjected to combined

    DEFF Research Database (Denmark)

    Zhou, Rong; Yu, Xiaqing; Ottosen, Carl-Otto

    2017-01-01

    and relative water content of all cultivars significantly decreased under drought and combined stress as compared to control. The net photosynthesis and starch content were significantly lower under drought and combined stress than control in the three cultivars. Stomata and pore length of the three cultivars......BACKGROUND: Abiotic stresses due to environmental factors could adversely affect the growth and development of crops. Among the abiotic stresses, drought and heat stress are two critical threats to crop growth and sustainable agriculture worldwide. Considering global climate change, incidence...... of combined drought and heat stress is likely to increase. The aim of this study was to shed light on plant growth performance and leaf physiology of three tomatoes cultivars ('Arvento', 'LA1994' and 'LA2093') under control, drought, heat and combined stress. RESULTS: Shoot fresh and dry weight, leaf area...

  4. THE STRESS RESISTANCE OF STUDENTS. THE PARADIGM OF SUBJECT PERSONALITY SELF- ORGANIZATION

    Directory of Open Access Journals (Sweden)

    Sergey I. Dyakov

    2016-01-01

    Full Text Available The aim of the investigation is to consider a problem of stress resistance of students in the context of subject self-organization of the personality. Methods. The following methods of research are used: questioning; psychological and diagnostic tests «Tolerance of Uncertainty» (NTN and «Personal Factors of Decisions» (PFD by T. V. Kornilova; original experimental experiences – «Coding», a technique of a self-assessment (scaling and «A locus control». While data processing the methods of mathematical statistics (SPSS 12 package – the correlation analysis of Pearson and the factorial analysis with rotation use a component by «verimax» method are applied. Results and scientific novelty. Types of subjectivity and strategy of stress resistance are allocated. The nature and a role of the emotional and stressful mechanism having information and semantic properties in its basis are disclosed. Communication of irresponsible mechanisms of mentality with the sphere of consciousness in the context of subjectivity of the personality is shown. Mechanisms of emotional and rational self-control of system of mental self-organization of the person are presented. The statistical and qualitative data opening communications between properties of subjectivity and stress resistance of the personality are empirically obtained. Variation of the relations and also types of subjectivity and stress resistance emphasized based on the results of the presented research. Original (author’s methods of studying of subjectivity and factors of stress resistance are presented. Practical significance. The revealed factors of subject self-organization reveal the stress-producing directions of the environment and the relation of the personality to situations of changes and uncertainty: and also indicate subject properties of resistance to stress which need to be developed to increase the level of health of students, to reduce risk of deviance and delinquency of

  5. Influence of subject choice, work overload and work stress on expatriate higher education teachers.

    OpenAIRE

    Naithani, Pranav

    2013-01-01

    Subject choice, work overload and work stress influence personal and professional lives of higher education teachers. Though the majority of higher education teachers in the Gulf Cooperation Council (GCC) countries are expatriates, yet research on expatriate higher education teachers working in the GCC countries is limited. This paper presents one part of the work life balance survey and focuses on the influence of subject choice, work overload and work stress on higher education teachers in ...

  6. Turbulent oscillating channel flow subjected to a free-surface stress.

    NARCIS (Netherlands)

    Kramer, W.; Clercx, H.J.H.; Armenio, V.

    2010-01-01

    The channel flow subjected to a wind stress at the free surface and an oscillating pressure gradient is investigated using large-eddy simulations. The orientation of the surface stress is parallel with the oscillating pressure gradient and a purely pulsating mean flow develops. The Reynolds number

  7. Cardio-respiratory response of young adult Indian male subjects to stress: Effects of progressive muscle relaxation

    Directory of Open Access Journals (Sweden)

    Arunima Chaudhuri

    2014-01-01

    Full Text Available Background: Stress and anxiety have become an integral part of our lives. Of late, this has resulted in the increase in incidence of hypertension and coronary heart disease. Objectives: To assess the effect of progressive muscle relaxation (PMR on young adult males and its role in the modulation of cardio-respiratory response on exposure to stress. Materials and Methods: This prospective cross-sectional study was conducted in a tertiary care referral hospital. Undergraduate male students under stress were chosen for the study. Fasting blood samples were drawn to analyze sugar and lipid profile, followed by anthropometric measurements and ECG. In the resting condition, blood pressure, pulse rate, and spirometric parameters; forced vital capacities (FVC, and forced expiratory volume in 1 sec (FEV 1 % were measured. Then, they were made to exercise with bicycle ergometer and post exercise, the vital parameters were recorded. All subjects were given a training of Jacobson′s Progressive Muscular Relaxation and asked to practice this technique for 3 months. All parameters were re-evaluated. Results: Significant decreases in resting heart rate, systolic blood pressure and diastolic blood pressure, total cholesterol, triglyceride, and low density lipoprotein (LDL cholesterol levels of subjects were seen after PMR training. Exercise-induced rise in heart rate and blood pressure were also significantly less in subjects following PMR training. Conclusion: Progressive muscle relaxation helps in modulation of heart rate, blood pressure, and lipid profile in healthy normal adult male individuals.

  8. SUBJECTIVE CURE RATES AFTER TVT PROCEDURE FOR TREATMENT OF FEMALE URINARY INCONTINENCE – A QUESTIONNAIRE BASED STUDY

    Directory of Open Access Journals (Sweden)

    Igor But

    2003-12-01

    Full Text Available Background. The aim of this study was to assess the subjective cure rate after the tension-free vaginal tape (TVT procedure in patients with stress (SUI and mixed (MUI urinary incontinence.Methods. This is a questionnaire based study done in 43 patients with SUI and 52 patients with MUI. In the assessement of the subjective cure rate the visual analogue scale and the symptom assessment index (SAI were used. Data were analyzed using nonparametric statistics.Results. The subjective cure rate assessed 19.6 months after TVT amounted to 89.3%. Urinary incontinence after TVT procedure was noted in 26 patients (27.4% and the majority of these women (73.1% were diagnosed with MUI. In patients with SUI and postoperative stable bladder a higher success rate was observed (96.7%. In 18.6% patients with SUI, de novo overactive bladder symptoms occurred. These patients estimated a significantly (p = 0.027 lower cure rate (81.9% after TVT procedure. In patients with MUI, the cure rate after TVT amounted to 85.6%. The subjective cure rate was lower (79.4% in case of persistent overactive bladder symptoms. However, it was significantly higher (97.5% in case of a postoperatively stable bladder (p = 0.016. In the group of MUI patients, the symptoms of overactive bladder disease resolved spontaneously in 17 patients (32.7% postoperatively. The patients were satisfied with TVT and 92.6% would recommend this procedure to others.Conclusions. The TVT procedure is a very effective method of treatment for stress as well as mixed urinary incontinence. The success rate of the procedure is high, however, it is influenced by bladder activity.

  9. Numerical evaluation of stress intensity factor for vessel and pipe subjected to thermal shock

    International Nuclear Information System (INIS)

    Kim, Y.W.; Lee, H.Y.; Yoo, B.

    1994-01-01

    The thermal weight function method and the finite element method were employed in the numerical computation of the stress intensity factor for a cracked vessel and the cracked pipe subjected to thermal shock. A wall subjected to thermal shock was analyzed, and it has been shown that the effect of thermal shock on the stress intensity factor is dominant for the crack with small crack length to thickness ratio. Convection at the crack face had an influence on the stress intensity factor in the early stage of thermal shock. (Author)

  10. Subjective discount rates in the general population and their predictive power for energy saving behavior

    International Nuclear Information System (INIS)

    Bruderer Enzler, Heidi; Diekmann, Andreas; Meyer, Reto

    2014-01-01

    Why do people sometimes refrain from saving energy even if it would pay off in monetary terms? Subjective discount rates present one possible explanation for this lack of foresight, but little is known about their level and reliability in the general population. With regard to behavior, persons with lower discount rates are expected to accept additional costs upfront more readily than those with higher discount rates. Based on a representative nation-wide study, the Swiss Environmental Survey 2007, and a follow-up survey, our analyses reveal that on average subjective discount rates are well above market interest rates and moderately stable over a time interval of four years. Income and education are negatively correlated with discount rates. Contrary to expectations, we did not find convincing support for an impact of discount rates on energy saving behavior. - Highlights: • Results of a large panel study in Switzerland. • Mean subjective discount rates in population are well above market interest rates. • Subjective discount rates are moderately stable over four years. • Theory suggests impact of subjective discount rates on energy saving behavior. • However, subjective discount rates do not contribute to explanation of energy saving behavior

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

    Directory of Open Access Journals (Sweden)

    Rogério Falleiros Carvalho

    2011-10-01

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

  12. Subjectivity

    Directory of Open Access Journals (Sweden)

    Jesús Vega Encabo

    2015-11-01

    Full Text Available In this paper, I claim that subjectivity is a way of being that is constituted through a set of practices in which the self is subject to the dangers of fictionalizing and plotting her life and self-image. I examine some ways of becoming subject through narratives and through theatrical performance before others. Through these practices, a real and active subjectivity is revealed, capable of self-knowledge and self-transformation. 

  13. Effect of mental challenge induced by movie clips on action potential duration in normal human subjects independent of heart rate.

    Science.gov (United States)

    Child, Nicholas; Hanson, Ben; Bishop, Martin; Rinaldi, Christopher A; Bostock, Julian; Western, David; Cooklin, Michael; O'Neil, Mark; Wright, Matthew; Razavi, Reza; Gill, Jaswinder; Taggart, Peter

    2014-06-01

    Mental stress and emotion have long been associated with ventricular arrhythmias and sudden death in animal models and humans. The effect of mental challenge on ventricular action potential duration (APD) in conscious healthy humans has not been reported. Activation recovery intervals measured from unipolar electrograms as a surrogate for APD (n=19) were recorded from right and left ventricular endocardium during steady-state pacing, whilst subjects watched an emotionally charged film clip. To assess the possible modulating role of altered respiration on APD, the subjects then repeated the same breathing pattern they had during the stress, but without the movie clip. Hemodynamic parameters (mean, systolic, and diastolic blood pressure, and rate of pressure increase) and respiration rate increased during the stressful part of the film clip (P=0.001). APD decreased during the stressful parts of the film clip, for example, for global right ventricular activation recovery interval at end of film clip 193.8 ms (SD, 14) versus 198.0 ms (SD, 13) during the matched breathing control (end film left ventricle 199.8 ms [SD, 16] versus control 201.6 ms [SD, 15]; P=0.004). Respiration rate increased during the stressful part of the film clip (by 2 breaths per minute) and was well matched in the respective control period without any hemodynamic or activation recovery interval changes. Our results document for the first time direct recordings of the effect of a mental challenge protocol on ventricular APD in conscious humans. The effect of mental challenge on APD was not secondary to emotionally induced altered respiration or heart rate. © 2014 American Heart Association, Inc.

  14. Hydrocortisone at stress-associated concentrations helps maintain human heart rate variability during subsequent endotoxin challenge.

    Science.gov (United States)

    Rassias, Athos J; Guyre, Paul M; Yeager, Mark P

    2011-12-01

    We evaluated the differential impact of stress-associated vs high pharmacologic concentrations of hydrocortisone pretreatment on heart rate variability (HRV) during a subsequent systemic inflammatory stimulus. Healthy volunteers were randomized to receive placebo (Control) and hydrocortisone at 1.5 μg/kg per minute (STRESS) or at 3.0 μg/kg per minute (PHARM) as a 6-hour infusion. The STRESS dose was chosen to replicate the condition of physiologic adrenal cortical output during acute systemic stress. The PHARM dose was chosen to induce a supraphysiologic concentration of cortisol. The next day, all subjects received 2 ng/kg Escherichia coli endotoxin (lipopolysaccharide). Heart rate variability was analyzed with the statistic approximate entropy (ApEn). A lower ApEn correlates with decreased HRV. At the 3-hour nadir, the decrease in ApEn in the STRESS group was significantly less compared to placebo (P statistically different. We also found that the maximal decrease in ApEn preceded maximal increase in heart rate in all groups. The decrease in R-R interval was maximal at 4 hours, whereas the ApEn nadir was 1 hour earlier at 3 hours. Pretreatment with a stress dose of hydrocortisone but not a higher pharmacologic dose maintained a significantly higher ApEn after endotoxin exposure when compared to a placebo. In addition, decreases in ApEn preceded increases in heart rate. Copyright © 2011 Elsevier Inc. All rights reserved.

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

    OpenAIRE

    Roselinde Kaiser Henderson; Hannah R. Snyder; Tina eGupta; Marie T. Banich; Marie T. Banich

    2012-01-01

    The ability to engage in goal-directed behavior despite exposure to stress is critical to resilience. Questions of how stress can impair or improve behavioral functioning are important in diverse settings, from athletic competitions to academic testing to clinical therapy. Previous research suggests that controllability is a key factor in the impact of stress on behavior: learning how to control stressors buffers people from the negative effects of stress on subsequent cognitively demanding ...

  16. When Does Stress Help or Harm? The Effects of Stress Controllability and Subjective Stress Response on Stroop Performance

    OpenAIRE

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

    2012-01-01

    The ability to engage in goal-directed behavior despite exposure to stress is critical to resilience. Questions of how stress can impair or improve behavioral functioning are important in diverse settings, from athletic competitions to academic testing. Previous research suggests that controllability is a key factor in the impact of stress on behavior: learning how to control stressors buffers people from the negative effects of stress on subsequent cognitively demanding tasks. In addition, r...

  17. An analytical solution describing the shape of a yield stress material subjected to an overpressure

    DEFF Research Database (Denmark)

    Hovad, Emil; Spangenberg, Jon; Larsen, P.

    2016-01-01

    as well as the spread length and height of the material when deformed in a box due to gravity. In the present work, the analytical solution is extended with the addition of an overpressure that acts over the entire body of the material. This extension enables finding the shape of a yield stress material......Many fluids and granular materials are able to withstand a limited shear stress without flowing. These materials are known as yields stress materials. Previously, an analytical solution was presented to quantify the yield stress for such materials. The yields stress is obtained based on the density...... with known density and yield stress when for instance deformed under water or subjected to a forced air pressure....

  18. Statistics of the Von Mises Stress Response For Structures Subjected To Random Excitations

    Directory of Open Access Journals (Sweden)

    Mu-Tsang Chen

    1998-01-01

    Full Text Available Finite element-based random vibration analysis is increasingly used in computer aided engineering software for computing statistics (e.g., root-mean-square value of structural responses such as displacements, stresses and strains. However, these statistics can often be computed only for Cartesian responses. For the design of metal structures, a failure criterion based on an equivalent stress response, commonly known as the von Mises stress, is more appropriate and often used. This paper presents an approach for computing the statistics of the von Mises stress response for structures subjected to random excitations. Random vibration analysis is first performed to compute covariance matrices of Cartesian stress responses. Monte Carlo simulation is then used to perform scatter and failure analyses using the von Mises stress response.

  19. Refining the multisystem view of the stress response: coordination among cortisol, alpha-amylase, and subjective stress in response to relationship conflict.

    Science.gov (United States)

    Laurent, Heidemarie K; Powers, Sally I; Granger, Douglas A

    2013-07-02

    This study investigated associations among young adults' hypothalamic-pituitary-adrenal axis activity, autonomic nervous system activity, and subjective stress in response to interpersonal conflict to better characterize coordination across stress systems. Seven saliva samples were collected from 199 young adult opposite-sex couples before, during, and after they discussed an unresolved relationship conflict. Samples were later assayed for cortisol and alpha-amylase (sAA). Couples rated anticipatory stress prior to the conflict and perceived stress immediately following the task. Growth curve modeling was used to examine two possible levels of within-person coordination across physiological systems: alignment between cortisol and sAA responses throughout the sampling period ("matched phase coordination"), and association between overall levels of cortisol and sAA in response to conflict ("average level coordination"). Whereas both partners showed the former type of coordination, only women showed the latter type. Positive anticipation of the stressor predicted stronger cortisol-sAA matched phase coordination for women. Pre-task ratings related to women's sAA, and post-task ratings related to both partners' cortisol responses. Implications for a multisystem interpretation of normal and pathological responses to daily stress are discussed. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. Refining the multisystem view of the stress response: Coordination among cortisol, alpha-amylase, and subjective stress in response to relationship conflict

    Science.gov (United States)

    Powers, Sally I.; Granger, Douglas A.

    2013-01-01

    This study investigated associations among young adults' hypothalamic-pituitary-adrenal axis activity, autonomic nervous system activity, and subjective stress in response to interpersonal conflict to better characterize coordination across stress systems. Seven saliva samples were collected from 199 young adult opposite-sex couples before, during, and after they discussed an unresolved relationship conflict. Samples were later assayed for cortisol and alpha-amylase (sAA). Couples rated anticipatory stress prior to the conflict and perceived stress immediately following the task. Growth curve modeling was used to examine two possible levels of within-person coordination across physiological systems: alignment between cortisol and sAA responses throughout the sampling period (“matched phase coordination”), and association between overall levels of cortisol and sAA in response to conflict (“average level coordination”). Whereas both partners showed the former type of coordination, only women showed the latter type. Positive anticipation of the stressor predicted stronger cortisol-sAA matched phase coordination for women. Pre-task ratings related to women's sAA, and post-task ratings related to both partners' cortisol responses. Implications for a multisystem interpretation of normal and pathological responses to daily stress are discussed. PMID:23684904

  1. Estimation of flow rates through intergranular stress corrosion cracks

    International Nuclear Information System (INIS)

    Collier, R.P.; Norris, D.M.

    1984-01-01

    Experimental studies of critical two-phase water flow, through simulated and actual intergranular stress corrosion cracks, were performed to obtain data to evaluate a leak flow rate model and investigate acoustic transducer effectiveness in detecting and sizing leaks. The experimental program included a parametric study of the effects of crack geometry, fluid stagnation pressure and temperature, and crack surface roughness on leak flow rate. In addition, leak detection, location, and leak size estimation capabilities of several different acoustic transducers were evaluated as functions of leak rate and transducer position. This paper presents flow rate data for several different cracks and fluid conditions. It also presents the minimum flow rate detected with the acoustic sensors and a relationship between acoustic signal strength and leak flow rate

  2. Hazard rate for a two-channel protective system subject to a high demand rate

    International Nuclear Information System (INIS)

    Oliveira, L.F.; Youngblood, R.; Melo, P.F.F.

    1989-01-01

    A basic figure of merit associated with a protective system for an industrial plant is the number of accidents expected to occur in the plant within a given period of time, with the system installed. By definition, in a plant equipped with a protective system, an accident can only happen if an initiating event (a demand) occurs while the protective system is unavailable, that is, while it is in one of its possible failed states. This means that the hazard rate or accident frequency depends on the demand rate and on the unavailability of the protective systems. It has long been recognized that the demand rate influences the unavailability of the protective system, and practical expressions incorporating that effect have been developed for single-channel (Lees, 1982) and multi-channel (Kumamoto and Henley 1978) protective systems. The effect has also been incorporated into a Markovian treatment of a plant protection system (Papazoglou and Cho, 1985). In a previous paper (Oliveira and Netto, 1987) a Markovian approach was used to derive analytical expressions for the evaluation of the plant hazard rate for a single-channel protective system, properly accounting for the effects of the demand and the repair rates. In this paper the authors present an extension of that model to the case of a plant equipped with a two-channel protective system

  3. A Comparison of Objective and Subjective Stress in Homogeneous Male and Female Teams in a Mars Simulation

    Science.gov (United States)

    Bishop, S.; Sundaresan, A.

    Introduction The role of stress and its impact on coping performance motivation behavior cognitive functioning and psychological well-being has become a key focus for long duration missions Since all extreme environments are characterized by significant physical demands e g skiing climbing EVAs as well as inescapable environmental characteristics e g imminent danger noise isolation confinement loss of normal sensory stimuli an examination of the impact of prolong stress in analogue environments should provide insight into developing effective support and countermeasures for long duration space crews The presence of even low levels of chronic stressors if not met with functional adaptation and or countermeasures has been shown to produce subjective symptoms of stress persistent performance incompetence accelerated fatiguability altered mood states increased rate of infections and decrements in attention and cognitive Gender has been shown to cut across both individual factors and group factors including response to stress and ways of coping Generally men and women differ in many arenas such as interaction and communication styles need for affiliation responses to crowding privacy and confined spaces Men and women in homogeneous groups interact in significantly different ways than those in mixed groups Therefore differences between genders on subjective and objective responses to stress are of interest The Mars Society Utah Desert Simulation MDRS facility provides a unique opportunity to examine the interaction of

  4. Oxidised fish oil does not influence established markers of oxidative stress in healthy human subjects

    DEFF Research Database (Denmark)

    Ottestad, Inger; Vogt, Gjermund; Retterstøl, Kjetil

    2012-01-01

    markers of oxidative stress, lipid peroxidation and inflammation, and the level of plasma n-3 FA after intake of oxidised fish oil. In a double-blinded randomised controlled study, healthy subjects (aged 18–50 years, n 54) were assigned into one of three groups receiving capsules containing either 8 g...... difference was observed between the fish oil groups. No changes in a variety of in vivo markers of oxidative stress, lipid peroxidation or inflammation were observed after daily intake of oxidised fish oil for 3 or 7 weeks, indicating that intake of oxidised fish oil may not have unfavourable short......-term effects in healthy human subjects....

  5. Relationships between Psychosocial Difficulties and Oxidative Stress Biomarkers in Women Subject to Intimate Partner Violence.

    Science.gov (United States)

    Kim, Jae Yop; Lee, Ji Hyeon; Song, Hyang Joo; Kim, Dong Goo; Yim, Yeong Shin

    2017-02-01

    Women subject to violence by their intimate partners often experience a range of psychosocial problems such as depression, excessive alcohol use, and stressful life events that, in turn, lead to health issues. This study examined psychosocial difficulties and oxidative stress levels in abused and non-abused Korean women and analyzed the relationship between psychosocial outcomes and oxidative stress levels. Markers were determined in 16 women (seven abused, nine non-abused). The two groups of women (abused and non-abused) were compared with respect to scores in depression, alcohol use, life stress events, and oxidative stress biomarkers using the Mann-Whitney U test. Correlations between depression, alcohol use, life stress events, and oxidative stress biomarkers were tested by the Spearman rank correlation coefficient. The abused women had significantly higher levels of oxidative stress markers and significantly lower levels of antioxidants than the non-abused women. Life stress events and oxidative biomarker levels were significantly correlated. These findings have implications for both social services providers and medical personnel when assessing abused women to ensure that they receive the most appropriate service. © 2016 National Association of Social Workers.

  6. The impact of education on subjective discount rate in Ugandan villages

    Czech Academy of Sciences Publication Activity Database

    Bauer, Michal; Chytilová, J.

    2010-01-01

    Roč. 58, č. 4 (2010), s. 643-669 ISSN 0013-0079 R&D Projects: GA MŠk LC542 Keywords : education * subjective discount rate * rural populations * Uganda Subject RIV: AH - Economics Impact factor: 1.392, year: 2010

  7. Modeling baroreflex regulation of heart rate during orthostatic stress

    DEFF Research Database (Denmark)

    Olufsen, Mette; Tran, Hien T.; Ottesen, Johnny T.

    2006-01-01

    . The model uses blood pressure measured in the finger as an input to model heart rate dynamics in response to changes in baroreceptor nerve firing rate, sympathetic and parasympathetic responses, vestibulo-sympathetic reflex, and concentrations of norepinephrine and acetylcholine. We formulate an inverse...... in healthy and hypertensive elderly people the hysteresis loop shifts to higher blood pressure values and its area is diminished. Finally, for hypertensive elderly people the hysteresis loop is generally not closed indicating that during postural change from sitting to standing, the blood pressure resettles......During orthostatic stress, arterial and cardiopulmonary baroreflexes play a key role in maintaining arterial pressure by regulating heart rate. This study, presents a mathematical model that can predict the dynamics of heart rate regulation in response to postural change from sitting to standing...

  8. Oxidative Stress and Antioxidants in Tomato (Solanum lycopersicum) Plants Subjected to Boron Toxicity

    Science.gov (United States)

    Cervilla, Luis M.; Blasco, Begoña; Ríos, Juan J.; Romero, Luis; Ruiz, Juan M.

    2007-01-01

    Background and Aims Boron (B) toxicity triggers the formation of reactive oxygen species in plant tissues. However, there is still a lack of knowledge as to how B toxicity affects the plant antioxidant defence system. It has been suggested that ascorbate could be important against B stress, although existing information is limited in this respect. The objective of this study was to analyse how ascorbate and some other components of the antioxidant network respond to B toxicity. Methods Two tomato (Solanum lycopersicum) cultivars (‘Kosaco’ and ‘Josefina’) were subjected to 0·05 (control), 0·5 and 2 mm B. The following were studied in leaves: dry weight; relative leaf growth rate; total and free B; H2O2; malondialdehyde; ascorbate; glutathione; sugars; total non-enzymatic antioxidant activity, and the activity of superoxide dismutase, catalase, ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, glutathione reductase, ascorbate oxidase and l-galactose dehydrogenase. Key Results The B-toxicity treatments diminished growth and boosted the amount of B, malondialdehyde and H2O2 in the leaves of the two cultivars, these trends being more pronounced in ‘Josefina’ than in ‘Kosaco’. B toxicity increased ascorbate concentration in both cultivars and increased glutathione only in ‘Kosaco’. Activities of antioxidant- and ascorbate-metabolizing enzymes were also induced. Conclusions High B concentration in the culture medium provokes oxidative damage in tomato leaves and induces a general increase in antioxidant enzyme activity. In particular, B toxicity increased ascorbate pool size. It also increased the activity of l-galactose dehydrogenase, an enzyme involved in ascorbate biosynthesis, and the activity of enzymes of the Halliwell–Asada cycle. This work therefore provides a starting point towards a better understanding of the role of ascorbate in the plant response against B stress. PMID:17660516

  9. Distribution of Side Abutment Stress in Roadway Subjected to Dynamic Pressure and Its Engineering Application

    Directory of Open Access Journals (Sweden)

    Yao Qiangling

    2015-01-01

    Full Text Available The borehole stress-meter was employed in this study to investigate the distribution of the side abutment stress in roadway subjected to dynamic pressure. The results demonstrate that the side abutment stress of the mining roadway reaches a peak value when the distance to the gob is 8 m and the distribution curve of the side abutment stress can be divided into three zones: stress rising zone, stress stabilizing zone, and stress decreasing zone. Further numerical investigation was carried out to study the effect of the coal mass strength, coal seam depth, immediate roof strength, and thickness on the distribution of the side abutment stress. Based on the research results, we determined the reasonable position of the mining roadway and the optimal width of the barrier pillar. The engineering application demonstrates that the retention of the barrier pillar with a width of 5 m along the gob as the haulage roadway for the next panel is feasible, which delivers favorable technological and economic benefits.

  10. Subjective heat stress of urban citizens: influencing factors and coping strategies

    Science.gov (United States)

    Kunz-Plapp, Tina; Hackenbruch, Julia; Schipper, Hans

    2014-05-01

    Given urbanization trend and a higher probability of heat waves in Europe, heat discomfort or heat stress for the population in cities is a growing concern that is addressed from various perspectives, such as urban micro climate, urban and spatial planning, human health, work performance and economic impacts. This presentation focuses on subjective heat stress experienced by urban citizens. In order to better understand individual subjective heat stress of urban citizens and how different measures to cope with heat stress in everyday life are applied, a questionnaire survey was conducted in Karlsruhe, Germany. Karlsruhe is located in one of the warmest regions in Germany and holds the German temperature record of 40.2°C in August 2003. In 2013, two hot weather periods with continuous heat warnings by the German Weather Service for 7 and 8 days occurred during the last 10 days of July and first 10 days of August 2013 with an inofficial maximum temperature of again 40.2°C on July 27th in Karlsruhe (not taken by the official network of the German Weather Service). The survey data was collected in the six weeks after the heat using an online-questionnaire on the website of the South German Climate Office that was announced via newspapers and social media channels to reach a wide audience in Karlsruhe. The questionnaire was additionally sent as paper version to groups of senior citizens to ensure having enough respondents from this heat sensitive social group in the sample. The 428 respondents aged 17-94 show differences in subjective heat stress experienced at home, at work and during various typical activities in daily routine. They differ also in the measures they used to adjust to and cope with the heat such as drinking more, evading the heat, seeking cooler places, changing daily routines, or use of air condition. Differences in heat stress can be explained by housing type, age, subjective health status, employment, and different coping measures and strategies

  11. Effect of Protectants on the Fermentation Performance of Wine Yeasts Subjected to Osmotic Stress

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    Andrea Caridi

    2003-01-01

    Full Text Available During alcoholic fermentation of must from dried grapes, yeasts are subjected to very high sugar concentrations, besides other environmental stresses, and they modify their metabolic behaviour giving low ethanol yield and abnormally high acetic acid production. To investigate the protective effect of catechin, inositol, and SO2 on wine yeasts, three thermotolerant strains of Saccharomyces cerevisiae, selected for wine making of must from dried grapes, and three strains of Saccharomyces selected for the production of wine, were inoculated in a sample of must at very high osmotic strength. A significant (p<0.01 or p<0.05 relationship between the addition of 100 mg/L of catechin, inositol or SO2 to the grape must and the change in the metabolic behaviour of the yeasts was observed. Compared to the control and depending on strain and protectant, the fermentation rate after 3 days increased up to 55 %, the ethanol content of the wines increased up to 16 %, the unitary succinic acid production increased up to 55 %, the unitary acetic acid production decreased up to 53 %, and the unitary glycerol production decreased up to 69 %. So by adding catechin, inositol or SO2 to the grape must it is possible to minimise the abnormal fermentation performance that wine yeasts exhibit in wine making of must from dried grapes.

  12. Creep and creep recovery of concrete subjected to triaxial compressive stresses at elevated temperature

    International Nuclear Information System (INIS)

    Ohnuma, Hiroshi; Abe, Hirotoshi

    1979-01-01

    In order to design rationally the vessels made of prestressed concrete for nuclear power stations and to improve the accuracy of high temperature creep analysis, the Central Research Institute of Electric Power Industry had carried out the proving experiments with scale models. In order to improve the accuracy of analysis, it is important to grasp the creep behavior of the concrete subjected to triaxial compressive stresses at high temperature as the basic property of concrete, because actual prestressed concrete vessels are in such conditions. In this paper, the triaxial compression creep test at 60 deg. C using the concrete specimens with same mixing ratio as the scale models is reported. The compressive strength of the concrete at the age of 28 days was 406 kg/cm 2 , and the age of the concrete at the time of loading was 63 days. Creep and creep recovery were measured for 5 months and 2 months, respectively. The creep of concrete due to uniaxial compression increased with temperature rise, and the creep strain at 60 deg. C was 2.54 times as much as that at 20 deg. C. The effective Poisson's ratio in triaxial compression creep was 0.15 on the average, based on the creep strain due to uniaxial compression at 60 deg. C. The creep recovery rate in high temperature, triaxial compression creep was 33% on the average. (Kako, I.)

  13. Alterations in Mitochondrial Oxidative Stress and Mitophagy in Subjects with Prediabetes and Type 2 Diabetes Mellitus

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    Shipra Bhansali

    2017-12-01

    Full Text Available Background and aimHyperglycemia-mediated oxidative stress impedes cell-reparative process like autophagy, which has been implicated in impairment of β-cell function in type 2 diabetes mellitus (T2DM. However, the role of mitophagy (selective mitochondrial autophagy in progression of hyperglycemia remains elusive. This study aimed to assess the impact of increasing severity of hyperglycemia on mitochondrial stress and mitophagy.Design and methodsA case–control study included healthy controls, subjects with prediabetes, newly diagnosed T2DM (NDT2DM and advanced duration of T2DM (ADT2DM (n = 20 each. Mitochondrial stress indices, transcriptional and translational expression of mitophagy markers (PINK1, PARKIN, MFN2, NIX, LC3-II, and LAMP-2 and transmission electron microscopic (TEM studies were performed in peripheral blood mononuclear cells.ResultsWith mild hyperglycemia in subjects with prediabetes, to moderate to severe hyperglycemia in NDT2DM and ADT2DM, a progressive rise in mitochondrial oxidative stress was observed. Prediabetic subjects exhibited significantly increased expression of mitophagy-related markers and showed a positive association with HOMA-β, whereas, patients with NDT2DM and ADT2DM demonstrated decreased expression, with a greater decline in ADT2DM subjects. TEM studies revealed significantly reduced number of distorted mitochondria in prediabetics, as compared to the T2DM patients. In addition, receiver operating characteristic analysis showed HbA1C > 7% (53 mmol/mol was associated with attenuated mitophagy.ConclusionIncreasing hyperglycemia is associated with progressive rise in oxidative stress and altered mitochondrial morphology. Sustenance of mitophagy at HbA1C < 7% (53 mmol/mol strengthens the rationale of achieving HbA1C below this cutoff for good glycemic control. An “adaptive” increase in mitophagy may delay progression to T2DM by preserving the β-cell function in subjects with prediabetes.

  14. Effect of heating rate on caustic stress corrosion cracking

    International Nuclear Information System (INIS)

    Indig, M.E.; Hoffman, N.J.

    1977-01-01

    To evaluate effects of a large water leak into the sodium side of a steam generator in a Liquid Metal Fast Breeder Reactor the Liquid Metal Engineering Center (LMEC) at Canoga Park, California, is performing a series of tests in a Large Leak Test Rig (LLTR). This test series involves heating a large steam generator that possibly contains localized pockets of aqueous caustic retained from a previous sodium-water reaction. Such pockets of caustic solution could be in contact with welds and other components that contain residual stresses up to the yield point. The LMEC and General Electric (GE) ran a series of tests to evaluate the effect of heating rate on caustic stress corrosion cracking (SCC) for alloys either used or considered for the LLTR. A summary of the temperatures and caustic concentration ranges that can result in caustic SCC for carbon steel and Type-304 stainless steel is given

  15. Reduced nicotine content cigarette advertising: How false beliefs and subjective ratings affect smoking behavior.

    Science.gov (United States)

    Mercincavage, Melissa; Saddleson, Megan L; Gup, Emily; Halstead, Angela; Mays, Darren; Strasser, Andrew A

    2017-04-01

    Tobacco advertising can create false beliefs about health harms that are reinforced by product design features. Reduced nicotine content (RNC) cigarettes may reduce harm, but research has not addressed advertising influences. This study examined RNC cigarette advertising effects on false harm beliefs, and how these beliefs - along with initial subjective ratings of RNC cigarettes - affect subsequent smoking behaviors. We further explored whether subjective ratings moderate associations between false beliefs and behavior. Seventy-seven daily, non-treatment-seeking smokers (66.2% male) participated in the first 15days of a randomized, controlled, open-label RNC cigarette trial. Participants viewed an RNC cigarette advertisement at baseline before completing a 5-day period of preferred brand cigarette use, followed by a 10-day period of RNC cigarette use (0.6mg nicotine yield). Participants provided pre- and post-advertisement beliefs, and subjective ratings and smoking behaviors for cigarettes smoked during laboratory visits. Viewing the advertisement increased beliefs that RNC cigarettes contain less nicotine and are healthier than regular cigarettes (p'saffected smoking behaviors. Significant interactions of strength and taste ratings with beliefs (p'ssmokers with less negative initial subjective ratings, greater false beliefs were associated with greater RNC cigarette consumption. Smokers may misconstrue RNC cigarettes as less harmful than regular cigarettes. These beliefs, in conjunction with favorable subjective ratings, may increase product use. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Flow rates in the head and neck lymphatics after food stimulation in healthy subjects

    Energy Technology Data Exchange (ETDEWEB)

    Thommesen, P.; Buhl, J.; Jansen, K.; Funch-Jensen, P.

    1981-02-01

    In 22 healthy subjects lymph transport flow rates was studied in the head lymphatics after food stimulation, mastication (chewing) and taste. After food stimulation there was a significantly higher transport rate (0.67 meter/hour) than after taste (0.57 meter/hour) and mastication (0.55 meter/hour). The calculation of transport flow rate was independent of quantitative distribution of radioactivity in the head and neck lymphatics, and it could therefore perhaps be of clinical value.

  17. Executive functioning performance predicts subjective and physiological acute stress reactivity: preliminary results.

    Science.gov (United States)

    Hendrawan, Donny; Yamakawa, Kaori; Kimura, Motohiro; Murakami, Hiroki; Ohira, Hideki

    2012-06-01

    Individual differences in baseline executive functioning (EF) capacities have been shown to predict state anxiety during acute stressor exposure. However, no previous studies have clearly demonstrated the relationship between EF and physiological measures of stress. The present study investigated the efficacy of several well-known EF tests (letter fluency, Stroop test, and Wisconsin Card Sorting Test) in predicting both subjective and physiological stress reactivity during acute psychosocial stress exposure. Our results show that letter fluency served as the best predictor for both types of reactivity. Specifically, the higher the letter fluency score, the lower the acute stress reactivity after controlling for the baseline stress response, as indicated by lower levels of state anxiety, negative mood, salivary cortisol, and skin conductance. Moreover, the predictive power of the letter fluency test remained significant for state anxiety and cortisol indices even after further adjustments for covariates by adding the body mass index (BMI) as a covariate. Thus, good EF performance, as reflected by high letter fluency scores, may dampen acute stress responses, which suggests that EF processes are directly associated with aspects of stress regulation. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. The effect of psychological stress on diet-induced thermogenesis and resting metabolic rate.

    Science.gov (United States)

    Weststrate, J A; Van der Kooy, K; Deurenberg, P; Hautvast, J G

    1990-04-01

    The effect of psychological stress on resting metabolic rate (RMR) and diet-induced thermogenesis (DIT) was assessed in 12 healthy young non-obese men of body weight 70.2 +/- 1.2 kg (mean +/- s.e.m.) and age 25 +/- 0.6 years. Two types of commercially available motion pictures (video films) were shown to the subjects during the measurements, ie stress-inducing horror films and as a control, romantic family films. The study was conducted according to a cross-over design. RMR and respiratory quotients were not significantly influenced by the type of film shown to the subjects. DIT, assessed over 4 h, was significantly increased by the stress-inducing treatment, 0.95 +/- 0.05 kJ/min (mean +/- s.e.m.) versus 0.76 +/- 0.06 kJ/min (control). No significant effect was observed of psychological stress on postprandial substrate oxidation rates, nutrient balances, and urinary catecholamine excretion.

  19. Hypnosis modulates behavioural measures and subjective ratings about external and internal awareness.

    Science.gov (United States)

    Demertzi, Athena; Vanhaudenhuyse, Audrey; Noirhomme, Quentin; Faymonville, Marie-Elisabeth; Laureys, Steven

    2015-12-01

    In altered subjective states, the behavioural quantification of external and internal awareness remains challenging due to the need for reports on the subjects' behalf. With the aim to characterize the behavioural counterpart of external and internal awareness in a modified subjective condition, we used hypnosis during which subjects remain fully responsive. Eleven right-handed subjects reached a satisfactory level of hypnotisability as evidenced by subjective reports on arousal, absorption and dissociation. Compared to normal wakefulness, in hypnosis (a) participants' self-ratings for internal awareness increased and self-ratings for external awareness decreased, (b) the two awareness components tended to anticorrelate less and the switches between external and internal awareness self-ratings were less frequent, and (c) participants' reaction times were higher and lapses in key presses were more frequent. The identified imbalance between the two components of awareness is considered as of functional relevance to subjective (meta)cognition, possibly mediated by allocated attentional properties brought about by hypnosis. Our results highlight the presence of a cognitive counterpart in resting state, indicate that the modified contents of awareness are measurable behaviourally, and provide leverage for investigations of more challenging altered conscious states, such as anaesthesia, sleep and disorders of consciousness. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Self-esteem, stress and self-rated health in family planning clinic patients

    Directory of Open Access Journals (Sweden)

    Young Rodney

    2004-06-01

    Full Text Available Abstract Background The independent effects of stress on the health of primary care patients might be different for different types of clinic populations. This study examines these relationships in a low-income female population of patients attending a family planning clinic. Methods This study investigated the relevance of different sources of personal stress and social support to self-rated health, adjusting for mental health, health behavior and demographic characteristics of subjects. Five hundred women who attended family planning clinics were surveyed and 345 completed the form for a response rate of 72 percent. Results Multiple logistic regression analysis revealed that liking oneself was related to good self-rated health (Odds ratio = 7.11, but stress or support from children, parents, friends, churches or spouses were not significant. White non-Hispanic and non-white non-Hispanic respondents had lower odds of reporting good self-rated health than Hispanic respondents (odds ratios were 2.87 and 2.81, respectively. Exercising five or more days per week also was related to good self-rated health. Smoking 20 or more cigarettes per day, and obese III were negatively related to good self-rated health (odds ratios were .19 and .22, respectively with corresponding p-values equal to .0043 and .0332. Conclusions Among younger low-income women, addressing low self-esteem might improve health status.

  1. Objective and subjective measurement of sleep disturbance in female trauma survivors with posttraumatic stress disorder.

    Science.gov (United States)

    Werner, Kimberly B; Griffin, Michael G; Galovski, Tara E

    2016-06-30

    Sleep disturbance may be the most often endorsed symptom of posttraumatic stress disorder (PTSD). Much of this research is based on subjective reports from trauma survivors; however, objective measures of sleep-related impairment have yielded findings inconsistent with self-report data. More studies investigating subjective and objective assessments concordantly are needed to understand sleep impairment in PTSD. The current study examined PTSD-related sleep disturbance in a female interpersonal violence cohort with full PTSD diagnoses (N=51) assessing subjective (global and daily diary measures) and objective (actigraphy) sleep measures concurrently. PTSD severity was positively associated with global, subjective reports of sleep impairment and insomnia. Subjective measures of sleep (including global sleep impairment, insomnia, and daily sleep diary reports of total sleep time, sleep efficiency, and sleep onset latency) were moderately to strongly correlated. However, no significant correlations between subjective and objective reports of sleep impairment were found in this cohort. Analyses demonstrated an overall elevation in subjectively reported sleep impairment when compared to objective measurement assessed concurrently. Findings demonstrate a lack of agreement between subjective and objective measurements of sleep in a PTSD-positive female cohort, suggesting objective and subjective sleep impairments are distinct sleep parameters that do not necessarily directly co-vary. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  2. Expression of NCED gene in colored cotton genotypes subjected to water stress

    Directory of Open Access Journals (Sweden)

    Alexandre M. S. de Souza

    Full Text Available ABSTRACT Considering that the NCED gene acts on the biosynthetic cascade of ABA, a hormone involved in the functioning of stomata and consequently in the regulation of transpiration, the aim of this research was to analyze the expression of this gene in colored cotton genotypes subjected to water stress at the beginning of plant growth. Four colored cotton genotypes were used, subjected to two managements, with and without water stress, beginning the treatments when the blade of the first true leaves reached an area that allowed the evaluation of gas exchange. For the studies of the expression of the NCED gene, via RT-qPCR, leaves were collected on three distinct dates: at 4 and 6 days of water stress, and after the plants regained their turgor. The differential expression of NCED was found in all genotypes, with higher levels of expression related to six days of water stress. When the stomatal conductance was around 25%, there was overexpression in the genotype CNPA 2009.13, followed by CNPA 2009.6, BRS SAFIRA and CNPA 2009.11, confirming the data obtained in the semi-quantitative RT-PCR. The NCED gene is involved in the response to water stress in the vegetative phase of colored cotton.

  3. Isometric arm strength and subjective rating of upper limb fatigue in two-handed carrying tasks.

    Science.gov (United States)

    Li, Kai Way; Chiu, Wen-Sheng

    2015-01-01

    Sustained carrying could result in muscular fatigue of the upper limb. Ten male and ten female subjects were recruited for measurements of isometric arm strength before and during carrying a load for a period of 4 minutes. Two levels of load of carrying were tested for each of the male and female subjects. Exponential function based predictive equations for the isometric arm strength were established. The mean absolute deviations of these models in predicting the isometric arm strength were in the range of 3.24 to 17.34 N. Regression analyses between the subjective ratings of upper limb fatigue and force change index (FCI) for the carrying were also performed. The results indicated that the subjective rating of muscular fatigue may be estimated by multiplying the FCI with a constant. The FCI may, therefore, be adopted as an index to assess muscular fatigue for two-handed carrying tasks.

  4. Radial Pressure Pulse and Heart Rate Variability in Heat- and Cold-Stressed Humans

    Directory of Open Access Journals (Sweden)

    Chin-Ming Huang

    2011-01-01

    Full Text Available This study aims to explore the effects of heat and cold stress on the radial pressure pulse (RPP and heart rate variability (HRV. The subjects immersed their left hand into 45°C and 7°C water for 2 minutes. Sixty healthy subjects (age 25±4 yr; 29 men and 31 women were enrolled in this study. All subjects underwent the supine temperature measurements of the bilateral forearms, brachial arterial blood pressure, HRV and RPP with a pulse analyzer in normothermic conditions, and thermal stresses. The power spectral low-frequency (LF and high-frequency (HF components of HRV decreased in the heat test and increased in the cold test. The heat stress significantly reduced radial augmentation index (AIr (P<.05, but the cold stress significantly increased AIr (P<.01. The spectral energy of RPP did not show any statistical difference in 0∼10 Hz region under both conditions, but in the region of 10∼50 Hz, there was a significant increase (P<.01 in the heat test and a significant decrease in the cold test (P<.01. The changes in AIr induced by heat and cold stress were significantly negatively correlated with the spectral energy in the region of 10∼50 Hz (SE10−50 Hz but not in the region of 0∼10 Hz (SE0−10 Hz. The results demonstrated that the SE10−50 Hz, which only possessed a small percentage in total pulse energy, presented more physiological characteristics than the SE0−10 Hz under the thermal stresses.

  5. Radial Pressure Pulse and Heart Rate Variability in Heat- and Cold-Stressed Humans

    Science.gov (United States)

    Huang, Chin-Ming; Chang, Hsien-Cheh; Kao, Shung-Te; Li, Tsai-Chung; Wei, Ching-Chuan; Chen, Chiachung; Liao, Yin-Tzu; Chen, Fun-Jou

    2011-01-01

    This study aims to explore the effects of heat and cold stress on the radial pressure pulse (RPP) and heart rate variability (HRV). The subjects immersed their left hand into 45°C and 7°C water for 2 minutes. Sixty healthy subjects (age 25 ± 4 yr; 29 men and 31 women) were enrolled in this study. All subjects underwent the supine temperature measurements of the bilateral forearms, brachial arterial blood pressure, HRV and RPP with a pulse analyzer in normothermic conditions, and thermal stresses. The power spectral low-frequency (LF) and high-frequency (HF) components of HRV decreased in the heat test and increased in the cold test. The heat stress significantly reduced radial augmentation index (AIr) (P < .05), but the cold stress significantly increased AIr (P < .01). The spectral energy of RPP did not show any statistical difference in 0 ~ 10 Hz region under both conditions, but in the region of 10 ~ 50 Hz, there was a significant increase (P < .01) in the heat test and a significant decrease in the cold test (P < .01). The changes in AIr induced by heat and cold stress were significantly negatively correlated with the spectral energy in the region of 10 ~ 50 Hz (SE10−50 Hz) but not in the region of 0 ~ 10 Hz (SE0−10 Hz). The results demonstrated that the SE10−50 Hz, which only possessed a small percentage in total pulse energy, presented more physiological characteristics than the SE0−10 Hz under the thermal stresses. PMID:21113292

  6. 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.

  7. Stress corrosion crack growth rate in dissimilar metal welds

    International Nuclear Information System (INIS)

    Fernandez, M. P.; Lapena, J.; Lancha, A. M.; Perosanz, F. J.; Navas, M.

    2000-01-01

    Dissimilar welds, used to join different sections in light water reactors, are potentially susceptible to stress corrosion cracking (SCC) in aqueous mediums characteristic of nuclear plants. However, the study of these The ma has been limited to evaluating the weld material susceptibility in these mediums. Little scarce data are available on crack growth rates due, fundamentally, to inadequate testing techniques. In order to address this lack of information the crack growth rate at the interface of ferritic SA 533 B-1 alloy and alloy I-82, in a dissimilar weld (SA533B-1/I-82/316L), was studied. Experiments were conducted in water at 288 degree centigrade, 8 ppm of O 2 and 1 μS/cm conductivity. (Author) 33 refs

  8. Sex and family history of cardiovascular disease influence heart rate variability during stress among healthy adults.

    Science.gov (United States)

    Emery, Charles F; Stoney, Catherine M; Thayer, Julian F; Williams, DeWayne; Bodine, Andrew

    2018-07-01

    Studies of sex differences in heart rate variability (HRV) typically have not accounted for the influence of family history (FH) of cardiovascular disease (CVD). This study evaluated sex differences in HRV response to speech stress among men and women (age range 30-49 years) with and without a documented FH of CVD. Participants were 77 adults (mean age = 39.8 ± 6.2 years; range: 30-49 years; 52% female) with positive FH (FH+, n = 32) and negative FH (FH-, n = 45) of CVD, verified with relatives of participants. Cardiac activity for all participants was recorded via electrocardiogram during a standardized speech stress task with three phases: 5-minute rest, 5-minute speech, and 5-minute recovery. Outcomes included time domain and frequency domain indicators of HRV and heart rate (HR) at rest and during stress. Data were analyzed with repeated measures analysis of variance, with sex and FH as between subject variables and time/phase as a within subject variable. Women exhibited higher HR than did men and greater HR reactivity in response to the speech stress. However, women also exhibited greater HRV in both the time and frequency domains. FH+ women generally exhibited elevated HRV, despite the elevated risk of CVD associated with FH+. Although women participants exhibited higher HR at rest and during stress, women (both FH+ and FH-) also exhibited elevated HRV reactivity, reflecting greater autonomic control. Thus, enhanced autonomic function observed in prior studies of HRV among women is also evident among FH+ women during a standardized stress task. Copyright © 2018 Elsevier Inc. All rights reserved.

  9. Relationship between job stress and subjective oral health symptoms in male financial workers in Japan.

    Science.gov (United States)

    Yoshino, Koichi; Suzuki, Seitaro; Ishizuka, Yoichi; Takayanagi, Atsushi; Sugihara, Naoki; Kamijyo, Hideyuki

    2017-04-07

    The aim was to assess subjective oral health symptoms and job stress, as measured by self-assessment of how demanding the job is, in male financial workers. The participants were recruited by applying screening procedures to a pool of Japanese registrants in an online database. For the stress check, 7 items about how demanding the job is were selected from The Brief Job Stress Questionnaire (BJSQ). Participants comprised a total of 950 financial male workers, ages 25 to 64. Participants who answered "I can't complete my work in the required time" had more decayed teeth (p=0.010). Participants who felt that their job is highly demanding (answered affirmatively to 6 or all 7 items) were more likely to report "often get food stuck between teeth" (p=0.030), "there are some foods I can't eat" (p=0.005), "bad breath" (p=0.032), and "jaw makes clicking sound" (p=0.032). The independent variable of total stress score of 24-28 was found to be correlated to at least three oral health symptoms (OR: 3.25; 95%CI: 1.66-6.35). These results indicate that certain job stress factors are associated with certain oral health symptoms, and that oral health symptoms are likely predictors of job stress.

  10. Temporal discounting and heart rate reactivity to stress.

    Science.gov (United States)

    Diller, James W; Patros, Connor H G; Prentice, Paula R

    2011-07-01

    Temporal discounting is the reduction of the value of a reinforcer as a function of increasing delay to its presentation. Impulsive individuals discount delayed consequences more rapidly than self-controlled individuals, and impulsivity has been related to substance abuse, gambling, and other problem behaviors. A growing body of literature has identified biological correlates of impulsivity, though little research to date has examined relations between delay discounting and markers of poor health (e.g., cardiovascular reactivity to stress). We evaluated the relation between one aspect of impulsivity, measured using a computerized temporal discounting task, and heart rate reactivity, measured as a change in heart rate from rest during a serial subtraction task. A linear regression showed that individuals who were more reactive to stress responded more impulsively (i.e., discounted delayed reinforcers more rapidly). When results were stratified by gender, the effect was observed for females, but not for males. This finding supports previous research on gender differences in cardiovascular reactivity and suggests that this type of reactivity may be an important correlate of impulsive behavior. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. The heart field effect: Synchronization of healer-subject heart rates in energy therapy.

    Science.gov (United States)

    Bair, Christine Caldwell

    2008-01-01

    Recent health research has focused on subtle energy and vibrational frequency as key components of health and healing. In particular, intentional direction of bioenergy is receiving increasing scientific attention. This study investigates the effect of the healer's electromagnetic (EM) heart field upon subjects during energy healing as measured by synchronization of heart rates and scores on a Subjective Units of Distress (SUD) scale and a Profile of Mood States (POMS) inventory. A nonequivalent pretest-posttest design was used based on heart rate comparisons between healer and subject and correlated with pre-and posttest SUD and POMS scores. Subjects included those who sat within the 3- to 4-foot "strong" range of the independent variable, the healer's heart field, while performing self-application of WHEE (the wholistic hybrid derived from EMDR [eye movement desensitization and reprocessing], and EFT [emotional freedom technique]), a meridian-based tapping technique (n=50); and those who performed the same process beyond the 15- to 18-foot range of the healer's EM heart field (n=41). The dependent variables were heart rate, SUD, and POMS inventory. All subjects completed these measures within 1 hour. Study results showed statistically significant heart-rate synchronization with the intervention population. In addition, SUD and POMS scores demonstrated considerably more improvement than in the control population, indicating additional benefit beyond the meridian-based therapies, such as WHEE, alone. Additional findings and future research recommendations are presented in this article.

  12. Workplace violence, psychological stress, sleep quality and subjective health in Chinese doctors: a large cross-sectional study

    Science.gov (United States)

    Sun, Tao; Gao, Lei; Li, Fujun; Shi, Yu; Xie, Fengzhe; Wang, Jinghui; Wang, Shuo; Zhang, Shue; Liu, Wenhui; Duan, Xiaojian; Liu, Xinyan; Zhang, Zhong; Li, Li; Fan, Lihua

    2017-01-01

    Background Workplace violence (WPV) against healthcare workers is known as violence in healthcare settings and referring to the violent acts that are directed towards doctors, nurses or other healthcare staff at work or on duty. Moreover, WPV can cause a large number of adverse outcomes. However, there is not enough evidence to test the link between exposure to WPV against doctors, psychological stress, sleep quality and health status in China. Objectives This study had three objectives: (1) to identify the incidence rate of WPV against doctors under a new classification, (2) to examine the association between exposure to WPV, psychological stress, sleep quality and subjective health of Chinese doctors and (3) to verify the partial mediating role of psychological stress. Design A cross-sectional online survey study. Setting The survey was conducted among 1740 doctors in tertiary hospitals, 733 in secondary hospital and 139 in primary hospital across 30 provinces of China. Participants A total of 3016 participants were invited. Ultimately, 2617 doctors completed valid questionnaires. The effective response rate was 86.8%. Results The results demonstrated that the prevalence rate of exposure to verbal abuse was the highest (76.2%), made difficulties (58.3%), smear reputation (40.8%), mobbing behaviour (40.2%), intimidation behaviour (27.6%), physical violence (24.1%) and sexual harassment (7.8%). Exposure to WPV significantly affected the psychological stress, sleep quality and self-reported health of doctors. Moreover, psychological stress partially mediated the relationship between work-related violence and health damage. Conclusion In China, most doctors have encountered various WPV from patients and their relatives. The prevalence of three new types of WPV have been investigated in our study, which have been rarely mentioned in past research. A safer work environment for Chinese healthcare workers needs to be provided to minimise health threats, which is a top

  13. Real-time simulation of thermal stresses and creep in plates subjected to transient heat input

    DEFF Research Database (Denmark)

    Hattel, Jesper Henri; Jacobsen, Torben Krogsdal; Hansen, P.N.

    1997-01-01

    -difference approach. It applies a general formulation which takes into account nonconstant material properties (e.g. temperature, material, or time dependency), heat-transfer coefficients, and creep. The temperature calculation applies a one-dimensional numerical model, whereas the stress analysis is semi......This paper presents a novel numerical technique for solving the temperature and stress fields in a plate subjected to arbitrarily varying transient boundary conditions (transient temperature and heat-flux variations) on a surface. The numerical method is based on the control-volume finite......-two-dimensional. Both plane stress and plane strain conditions are considered as extreme cases. It is shown that, by using the developed numerical technique, very fast real-time simulations can be performed. The method has proved its applicability in e.g. high-pressure die-casting, and applications to this industrial...

  14. Personality in Free-Ranging Hanuman Langur (Semnopithecus entellus) Males: Subjective Ratings and Recorded Behavior

    Czech Academy of Sciences Publication Activity Database

    Konečná, M.; Lhota, S.; Weiss, A.; Urbánek, Tomáš; Adamová, T.; Pluháček, J.

    2008-01-01

    Roč. 122, č. 4 (2008), s. 379-389 ISSN 0735-7036 Institutional research plan: CEZ:AV0Z70250504 Keywords : trait rating * questionnaires * behavioral indices Subject RIV: AN - Psychology Impact factor: 2.081, year: 2008

  15. 29 CFR 4.118 - Contracts for carriage subject to published tariff rates.

    Science.gov (United States)

    2010-07-01

    ... Application of the McNamara-O'Hara Service Contract Act Specific Exclusions § 4.118 Contracts for carriage... carriage. The contracts excluded from the reach of the Act by this exemption are typically those where... 29 Labor 1 2010-07-01 2010-07-01 true Contracts for carriage subject to published tariff rates. 4...

  16. A Framework for Control System Design Subject to Average Data-Rate Constraints

    DEFF Research Database (Denmark)

    Silva, Eduardo; Derpich, Milan; Østergaard, Jan

    2011-01-01

    This paper studies discrete-time control systems subject to average data-rate limits. We focus on a situation where a noisy linear system has been designed assuming transparent feedback and, due to implementation constraints, a source-coding scheme (with unity signal transfer function) has to be ...

  17. Violence Exposure, Posttraumatic Stress, and Subjective Well-Being in a Sample of Russian Adults: A Facebook-Based Study.

    Science.gov (United States)

    Bogolyubova, Olga; Tikhonov, Roman; Ivanov, Victor; Panicheva, Polina; Ledovaya, Yanina

    2017-03-01

    Exposure to violence has been shown to negatively affect mental health and well-being. The goal of this Facebook-based study was to describe the rates of exposure to violence in a sample of Russian adults and to assess the impact of these experiences on subjective well-being and victimization-related psychological distress. Three types of victimization were assessed: physical assault by a stranger, physical assault by someone known to victim, and nonconsensual sexual experiences. The 5-item World Health Organization Well-Being Index (WHO-5) was used to assess subjective well-being, and Primary Care PTSD Screen (PC-PTSD) was employed as an indicator of victimization-related psychological distress. Data were obtained from 6,724 Russian-speaking Facebook users. Significant levels of lifetime victimization were reported by the study participants. Lifetime physical assault by a stranger, physical assault by someone known to victim, and sexual assault were reported by 56.9%, 64.2%, and 54.1% of respondents, respectively. Respondents exposed to violence were more likely to report posttraumatic stress symptoms and lower levels of subjective well-being. Participants who were exposed to at least one type of violence were more likely to experience symptoms of traumatic stress ( U = 1,794,250.50, p violence was associated with more severe traumatic stress symptoms ( r s = .257, p violence ( t = 8.37, p violence exposure is associated with reduced well-being among Russian adults. Our findings highlight the negative impact of violence exposure on subjective well-being and underscore the necessity to develop programs addressing violence exposure in Russian populations.

  18. Effect of stress and intesity of mobile phone using on the health and subjective symptoms in GSM workers

    Directory of Open Access Journals (Sweden)

    Agata Szyjkowska

    2017-10-01

    Full Text Available Background: There are no available data on the health consequences that may result from the synergistic effects of electromagnetic fields (EMF and stress. Understanding the mechanisms of the simultaneous exposure will make it possible to develop procedures to minimize adverse health effects in professionals using mobile phones. Material and Methods: A questionnaire survey was conducted in 600 randomly selected people to obtain data on their health status and the prevalence of subjective symptoms related to the mobile phones using. Among them, there were 208 GSM Network employees, to whom the Perceived Stress Scale and Assessment of Stress at Work Questionnaire were sent. Eighty-nine completed questionnaires were returned (response rate – 42.8%. Results: The mean age of respondents was 30.3 years (standard deviation (SD = 7.7, time of occupational use of mobile phone – 4.1 years (SD = 1.7, the level of occupational stress – 95.3 (SD = 19.1. A significant percentage of people (62.8% complained of the frequent difficulties in coping with problems of everyday life, and 57.4% had a fairly frequent problems with managing their own affairs. Significant differences in the life stress were detected between groups with different time of phone use (p = 0.03, and in occupational stress level, significant differences were noted between the 2 groups differing in the length of the conversation (p = 0.05. The risk of headache, associated (odds ratio (OR = 4.2, p = 0.008 or not associated (OR = 2.97, p = 0.04 with calls on mobile phone, adjusted for stress, was significantly higher in people speaking via mobile more than 60 min/day than in those talking less. Conclusions: The study indicates that both stressors acting at the same time (EMF from cell phone and stress adversely affect the well-being of workers and increase the risk of subjective symptoms. Med Pr 2017;68(5:617–628

  19. [Effect of stress and intesity of mobile phone using on the health and subjective symptoms in GSM workers].

    Science.gov (United States)

    Szyjkowska, Agata; Gadzicka, Elżbieta; Szymczak, Wiesław; Bortkiewicz, Alicja

    2017-07-26

    There are no available data on the health consequences that may result from the synergistic effects of electromagnetic fields (EMF) and stress. Understanding the mechanisms of the simultaneous exposure will make it possible to develop procedures to minimize adverse health effects in professionals using mobile phones. A questionnaire survey was conducted in 600 randomly selected people to obtain data on their health status and the prevalence of subjective symptoms related to the mobile phones using. Among them, there were 208 GSM Network employees, to whom the Perceived Stress Scale and Assessment of Stress at Work Questionnaire were sent. Eighty-nine completed questionnaires were returned (response rate - 42.8%). The mean age of respondents was 30.3 years (standard deviation (SD) = 7.7), time of occupational use of mobile phone - 4.1 years (SD = 1.7), the level of occupational stress - 95.3 (SD = 19.1). A significant percentage of people (62.8%) complained of the frequent difficulties in coping with problems of everyday life, and 57.4% had a fairly frequent problems with managing their own affairs. Significant differences in the life stress were detected between groups with different time of phone use (p = 0.03), and in occupational stress level, significant differences were noted between the 2 groups differing in the length of the conversation (p = 0.05). The risk of headache, associated (odds ratio (OR) = 4.2, p = 0.008) or not associated (OR = 2.97, p = 0.04) with calls on mobile phone, adjusted for stress, was significantly higher in people speaking via mobile more than 60 min/day than in those talking less. The study indicates that both stressors acting at the same time (EMF from cell phone and stress) adversely affect the well-being of workers and increase the risk of subjective symptoms. Med Pr 2017;68(5):617-628. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

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

    Science.gov (United States)

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

    2009-03-01

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

  1. Flow rates in the head and neck lymphatics after food stimulation in healthy subjects

    International Nuclear Information System (INIS)

    Thommesen, P.; Buhl, J.; Jansen, K.; Funch-Jensen, P.; Central Hospital Randers; Municipal Hospital Aarhus

    1981-01-01

    In 22 healthy subjects lymph transport flow rates was studied in the head lymphatics after food stimulation, mastication (chewing) and taste. After food stimulation there was a significantly higher transport rate (0.67 meter/hour) than after taste (0.57 meter/hour) and mastication (0.55 meter/hour). The calculation of transport flow rate was independent of quantitative distribution of radioactivity in the head and neck lymphatics, and it could therefore perhaps be of clinical value. (orig.) [de

  2. Subjective stress, role perceptions and coping strategies among mental health nurses

    Directory of Open Access Journals (Sweden)

    Spyridoula Doupi

    2015-09-01

    Full Text Available Introduction: Lack of nursing personnel, the consequent nurses’ work pressure within health care units and the particularities of nursing services provision in mental health institutions, render the examination of stress at work a necessity. Aim: The current study aims in presenting the stress levels among nurses in mental health institutions, their perceptions of the nursing role and the coping strategies they use. Methodology: This cross-sectional descriptive study was conducted in the population of 85 nurses in mental health open and closed units of two public hospitals of Attica, one psychiatric and one general. Participants filled in questionnaires on demographic characteristics, perceived stress, role conflict and ambiguity and ways of coping with stressful situations. Results: 57 women (67,1% and 28 men (32,9%, aged (mean 41,08 years, mostly married (74,1% and graduates of Technological institutions (29,4% participated in the study. Most were working 16-20 years (32,9%, were nurses (71,8% and were being occupied in a psychiatric structure for more than 21 years (27,1%. Female nurses had a greater amount of role ambiguity (p=0.048 and higher levels of stress (p=0.007. The same pattern was observed to those who worked for more years (p=0.038. Those who were not satisfied with their job suffered from greater role ambiguity (p<0.001 and conflict (p<0.001, while the graduates of secondary education and specialised nurses had higher levels of stress (p=0.004. Nurses with most working years in a psychiatric facility, experienced greater role conflict (p=0.034. Role ambiguity was positively associated with role conflict (p<0.001, perceived stress (p=0.006, positive approach strategy (negatively; p=0.003, self-rated health (negatively; p=0.003 and age (negatively; p=0.006. Perceived stress was negatively associated with positive approach (p=0.019 and self-rated health (p<0.001. Finally, positive approach was positively associated with social

  3. Behaviour of a pre-stressed concrete pressure-vessel subjected to a high temperature gradient

    International Nuclear Information System (INIS)

    Dubois, F.

    1965-01-01

    After a review of the problems presented by pressure-vessels for atomic reactors (shape of the vessel, pressures, openings, foundations, etc.) the advantages of pre-stressed concrete vessels with respect to steel ones are given. The use of pre-stressed concrete vessels however presents many difficulties connected with the properties of concrete. Thus, because of the absence of an exact knowledge of the material, it is necessary to place a sealed layer of steel against the concrete, to have a thermal insulator or a cooling circuit for limiting the deformations and stresses, etc. It follows that the study of the behaviour of pre-stressed concrete and of the vessel subjected- to a high temperature gradient can yield useful information. A one-tenth scale model of a pre-stressed concrete cylindrical vessel without any side openings and without a base has been built. Before giving a description of the tests the authors consider some theoretical aspects concerning 'scale model-actual structure' similitude conditions and the calculation of the thermal and mechanical effects. The pre-stressed concrete model was heated internally by a 'pyrotenax' element and cooled externally by a very strong air current. The concrete was pre-stressed using horizontal and vertical cables held at 80 kg/cm 2 ; the thermal gradient was 160 deg. C. During the various tests, measurements were made of the overall and local deformations, the changes in water content, the elasticity modulus, the stress and creep of the cables and the depths of the cracks. The overall deformations observed are in line with thermal deformation theories and the creep of the cables attained 20 to 30 per cent according to their position relative to the internal surface. The dynamic elasticity modulus decreased by half but the concrete keeps its good mechanical properties. Finally, cracks 8 to 12 cm deep and 2 to 3 mms wide appeared in that part of the concrete which was not pre-stressed. The results obtained make it

  4. Subjective thermal sensation and human body exergy consumption rate: analysis and correlation

    DEFF Research Database (Denmark)

    Simone, Angela; Dovjak, M.; Kolarik, Jakub

    2011-01-01

    , it is reasonable to consider both the exergy flows in building and those within the human body. There is a need to verify the human-body exergy model with the Thermal-Sensation (TS) response of subjects exposed to different combinations of indoor climate parameters (temperature, humidity, etc.). First results...... available on the relation between human-body exergy consumption rates and subjectively assessed thermal sensation showed that the minimum human body exergy consumption rate is associated with thermal sensation votes close to thermal neutrality, tending to slightly cool side of thermal sensation. By applying...... the exergy concept to the built indoor environment, additional results are going to be explored. By using the data available so far of operative temperature (to), the human body exergy consumption rates increase as to increases above 24°C or decreases below 22°C at relative humidity (RH) lower than 50...

  5. Dislocation density and mechanical threshold stress in OFHC copper subjected to SHPB loading and plate impact

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Qiushi [National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, Sichuan, 621900 (China); Zhao, Feng, E-mail: ifpzfeng@163.com [National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, Sichuan, 621900 (China); Fu, Hua; Li, Kewu [National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, Sichuan, 621900 (China); Liu, Fusheng [Key Laboratory of Advanced Technologies of Materials, Southwest Jiaotong University, Chengdu, Sichuan, 610031 (China)

    2017-05-17

    The dislocation density and mechanical threshold stress (MTS) of oxygen-free high-thermal-conductivity (OFHC) copper loaded at strain rates in the range of 10{sup 2} to 10{sup 6} s{sup −1} were measured. Moderate-strain-rate (10{sup 2} to 10{sup 4} s{sup −1}) experiments were performed using a Split Hopkinson Pressure Bar (SHPB). A steel collar was placed around each specimen to control the maximum loading strain. High-strain-rate (10{sup 5} to 10{sup 6} s{sup −1}) experiments were carried out using a 57-mm-bore single-stage gas gun. The radial release effect was eliminated using the momentum trapping technique. The loaded samples were recovered, and the dislocation characteristics and dislocation density were determined by X-ray diffraction profile analysis. The fraction of the screw dislocation was found to decrease with increasing loading strain and strain rate. The dislocation density was found to lie between 1.8×10{sup 14} and 2.2×10{sup 15} m{sup −2}. Quasi-static reload compression tests were performed on the recovered samples at room temperature. The mechanical threshold stress (or the flow stress at 0 K) was obtained by fitting the reload stress–strain data to the MTS model. The results of analysis of the equivalent strain, mechanical threshold stress, and dislocation density measurements suggest that the relation between the mechanical threshold stress and the dislocation density can be described well by the Taylor relationship.

  6. Effects of Changing Stress Amplitude on the Rate of Fatigue-Crack Propagation in Two Aluminum Alloys

    Science.gov (United States)

    Hudson, C. Michael; Hardrath, Herbert F.

    1961-01-01

    A series of fatigue tests with specimens subjected to constant amplitude and two-step axial loads were conducted on 12-inch-wide sheet specimens of 2024-T3 and 7075-T6 aluminum alloy to study the effects of a change in stress level on fatigue-crack propagation. Comparison of the results of the tests in which the specimens were tested at first a high and then a low stress level with those of the constant-stress- amplitude tests indicated that crack propagation was generally delayed after the transition to the lower stress level. In the tests in which the specimens were tested at first a low and then a high stress level, crack propagation continued at the expected rate after the change in stress levels.

  7. Gender differences in subjective health complaints in adolescence: The roles of self-esteem, stress from schoolwork and body dissatisfaction.

    Science.gov (United States)

    Aanesen, Fiona; Meland, Eivind; Torp, Steffen

    2017-06-01

    The aims of this study were to examine subjective health complaints among Norwegian adolescents and assess the development of gender differences in subjective health complaints between age 14 and 16; to investigate whether self-esteem, stress from schoolwork or body dissatisfaction affected adolescents' subjective health complaints; and determine whether these factors could explain the excess of subjective health complaints among girls. We used multiple linear regression analyses to analyse longitudinal survey data from 751 Norwegian adolescents at the ages of 14 and 16. The results from various cross-sectional and prospective analyses were compared. Girls reported more subjective health complaints than boys, and gender differences increased from age 14 to 16. Self-esteem and stress from schoolwork had cross-sectional and prospective associations with subjective health complaints. Stress from schoolwork at age 14 was also associated with changes in subjective health complaints from age 14 to 16. The cross-sectional mediation analyses indicated that self-esteem and stress from schoolwork accounted for 61% of the excess of subjective health complaints among girls at age 16. The same variables measured at age 14 accounted for 24% of the gender differences in subjective health complaints two years later. The investigated factors could not account for the increase in gender differences in subjective health complaints between ages 14 and 16. The findings showed that self-esteem and stress from schoolwork were associated with subjective health complaints during adolescence. These factors could partially explain the excess of subjective health complaints among girls.

  8. GAS EXCHANGE IN YOUNG PLANTS OF Tabebuia aurea(Bignoniaceae Juss. SUBJECTED TO FLOODING STRESS1

    Directory of Open Access Journals (Sweden)

    Ademir Kleber Morbeck Oliveira

    2016-02-01

    Full Text Available ABSTRACT The Paratudo (Tabebuia aurea is a species occurring in the Pantanal of Miranda, Mato Grosso do Sul, Brazil, an area characterized by seasonal flooding. To evaluate the tolerance of this plant to flooding, plants aged four months were grown in flooded soil and in non-flooded soil (control group. Stomatal conductance, transpiration and CO2 assimilation were measured during the stress (48 days and recovery (11 days period, totalling 59 days. The values of stomatal conductance of the control group and stressed plants at the beginning of the flooded were 0.33 mol m-2s-1 and reached 0.02 mol m-2 s-1 (46th day at the end of this event. For the transpiration parameter, the initial rate was 3.1 mol m s-1, and the final rate reached 0.2 or 0.3 mol m-2 s-1 (47/48 th day. The initial photosynthesis rate was 8.9 mmol m-2s-1 and oscillated after the sixth day, and the rate reached zero on the 48th day. When the photosynthesis rate reached zero, the potted plants were dried, and the rate was analyzed (11th day. The following values were obtained for dried plants: stomatal conductance = 0.26 mol m-2 s-1, transpiration rate = 2.5 mol m-2 s-1 and photosynthesis rate = 7.8 mmol m-2 s-1. Flooded soil reduced photosynthesis and stomatal conductance, leading to the hypertrophy of the lenticels. These parameters recovered and after this period, and plants exhibited tolerance to flooding stress by reducing their physiological activities.

  9. Merging physical parameters and laboratory subjective ratings for the soundscape assessment of urban squares.

    Science.gov (United States)

    Brambilla, Giovanni; Maffei, Luigi; Di Gabriele, Maria; Gallo, Veronica

    2013-07-01

    An experimental study was carried out in 20 squares in the center of Rome, covering a wide range of different uses, sonic environments, geometry, and architectural styles. Soundwalks along the perimeter of each square were performed during daylight and weekdays taking binaural and video recordings, as well as spot measurements of illuminance. The cluster analysis performed on the physical parameters, not only acoustic, provided two clusters that are in satisfactory agreement with the "a priori" classification. Applying the principal component analysis (PCA) to five physical parameters, two main components were obtained which might be associated to two environmental features, namely, "chaotic/calm" and "open/enclosed." On the basis of these two features, six squares were selected for the laboratory audio-video tests where 32 subjects took part filling in a questionnaire. The PCA performed on the subjective ratings on the sonic environment showed two main components which might be associated to two emotional meanings, namely, "calmness" and "vibrancy." The linear regression modeling between five objective parameters and the mean value of subjective ratings on chaotic/calm and enclosed/open attributes showed a good correlation. Notwithstanding these interesting results being limited to the specific data set, it is worth pointing out that the complexity of the soundscape quality assessment can be more comprehensively examined merging the field measurements of physical parameters with the subjective ratings provided by field and/or laboratory tests.

  10. An open-label trial of L-5-hydroxytryptophan in subjects with romantic stress.

    Science.gov (United States)

    Emanuele, Enzo; Bertona, Marco; Minoretti, Piercarlo; Geroldi, Diego

    2010-01-01

    This open-label trial assessed the clinical efficacy of L-5-hydroxytryptophan (5-HTP), a natural serotonin precursor, in nondepressed young subjects with high levels of romantic stress. Since both neurotrophins and serotonin have been linked to human romantic attachment, we sought to investigate the changes in serum brain-derived neurotrophic factor (BDNF) levels and platelet serotonin content in relation to the changes in romantic stress throughout the study. A total of 15 healthy subjects (11 females and 4 males, mean age: 23.3 ± 2.1 years) who experienced a recent romantic break-up or reported recent romantic problems took part in the study. The participants were treated openly for 6 weeks with L-5-hydroxytryptophan (60 mg Griffonia simplicifolia extract containing 12.8 mg 5-HTP b.i.d., Amorex, Coropharm, Villach, Austria). The subjects were evaluated at baseline, at 3 weeks and at the end of the 6-week trial using an adapted version of the Seiffge-Krenke's Problem Questionnaire. BDNF and platelet serotonin content were determined at baseline, at 3 weeks, and after the completion of the 6-week trial. We observed significant improvements in romantic stress scores from weeks 0 through 3 (p=0.007) but no further significant improvement was evident from weeks 3 through 6 (p=0.19). At 6 weeks, subjects had a significant increase from baseline in both BDNF and platelet serotonin values. Our data suggest that direct modulation of the serotonergic system may have use for the treatment of psychological suffering associated with unreciprocated romantic love.

  11. Subjective health complaints in older adolescents are related to perceived stress, anxiety and gender - a cross-sectional school study in Northern Sweden.

    Science.gov (United States)

    Wiklund, Maria; Malmgren-Olsson, Eva-Britt; Ohman, Ann; Bergström, Erik; Fjellman-Wiklund, Anncristine

    2012-11-16

    Negative trends in adolescent mental and subjective health are a challenge to public health work in Sweden and worldwide. Self-reported mental and subjective health complaints such as pain, sleeping problems, anxiety, and various stress-related problems seem to have increased over time among older adolescents, especially girls. The aim of this study has therefore been to investigate perceived stress, mental and subjective health complaints among older adolescents in Northern Sweden. Data were derived from a cross-sectional school-based survey with a sample consisting of 16-18 year olds (n = 1027), boys and girls, in the first two years of upper secondary school, from different vocational and academic programmes in three public upper secondary schools in a university town in northern Sweden. Prevalence of perceived stress, subjective health complaints, general self-rated health, anxiety, and depression were measured using a questionnaire, including the Hospital Anxiety and Depression Scale (HADS). A large proportion of both girls and boys reported health complaints and perceived stress. There was a clear gender difference: two to three times as many girls as boys reported subjective health complaints, such as headache, tiredness and sleeping difficulties and musculoskeletal pain, as well as sadness and anxiety. High pressure and demands from school were experienced by 63.6% of girls and 38.5% of boys. Perceived stress in the form of pressure and demands correlated strongly with reported health complaints (r = 0.71) and anxiety (r = 0.71). The results indicate that mental and subjective health complaints are prevalent during adolescence, especially in girls, and furthermore, that perceived stress and demands may be important explanatory factors. Future studies should pay attention to the balance between gender-related demands, perceived control and social support, particularly in the school environment, in order to prevent negative strain and stress

  12. Oxidative stress and inflammation in lean and obese subjects with polycystic ovary syndrome.

    Science.gov (United States)

    Blair, Sarah A; Kyaw-Tun, Tommy; Young, Ian S; Phelan, Niamh A; Gibney, James; McEneny, Jane

    2013-01-01

    To determine whether polycystic ovary syndrome (PCOS) independently influences oxidative stress and inflammation or if the culprit is the comorbidities of obesity and/or insulin resistance common to this condition. Thirty women with PCOS were matched for age, body mass index and insulin resistance with 30 control subjects. Oxidative stress was examined by measuring the total oxidant status (TOS) and total antioxidant capacity (TAC) by spectrophotometric assay. The inflammatory biomarkers, C-reactive protein, plasminogen activator inhibitor-1, myeloperoxidase, neopterin, and serum amyloid A were measured by ELISA methodologies. Oxidative status was increased in the PCOS subjects relative to their weight-matched controls (TOS: obese PCOS patients vs. obese controls, 42.42 +/- 4.49 vs. 32.57 +/- 1.97, plean PCOS patients vs. lean controls, 33.69 +/- 1.59 vs. 28.69 +/- 1.18 micromol H2O2 Equiv/L, p lean PCOS group relative to their weight-matched controls (TAC: lean PCOS patients vs. lean controls, 1.10 +/- 0.09 vs. 1.49 +/- 0.03 nmol Trolox Equiv/L, p PCOS independently influenced oxidative stress. Overall, the presence of PCOS may increase cardiovascular risk.

  13. Psilocybin links binocular rivalry switch rate to attention and subjective arousal levels in humans.

    Science.gov (United States)

    Carter, Olivia L; Hasler, Felix; Pettigrew, John D; Wallis, Guy M; Liu, Guang B; Vollenweider, Franz X

    2007-12-01

    Binocular rivalry occurs when different images are simultaneously presented to each eye. During continual viewing of this stimulus, the observer will experience repeated switches between visual awareness of the two images. Previous studies have suggested that a slow rate of perceptual switching may be associated with clinical and drug-induced psychosis. The objective of the study was to explore the proposed relationship between binocular rivalry switch rate and subjective changes in psychological state associated with 5-HT2A receptor activation. This study used psilocybin, the hallucinogen found naturally in Psilocybe mushrooms that had previously been found to induce psychosis-like symptoms via the 5-HT2A receptor. The effects of psilocybin (215 microg/kg) were considered alone and after pretreatment with the selective 5-HT2A antagonist ketanserin (50 mg) in ten healthy human subjects. Psilocybin significantly reduced the rate of binocular rivalry switching and increased the proportion of transitional/mixed percept experience. Pretreatment with ketanserin blocked the majority of psilocybin's "positive" psychosis-like hallucinogenic symptoms. However, ketanserin had no influence on either the psilocybin-induced slowing of binocular rivalry or the drug's "negative-type symptoms" associated with reduced arousal and vigilance. Together, these findings link changes in binocular rivalry switching rate to subjective levels of arousal and attention. In addition, it suggests that psilocybin's effect on binocular rivalry is unlikely to be mediated by the 5-HT2A receptor.

  14. Modeling the time--varying subjective quality of HTTP video streams with rate adaptations.

    Science.gov (United States)

    Chen, Chao; Choi, Lark Kwon; de Veciana, Gustavo; Caramanis, Constantine; Heath, Robert W; Bovik, Alan C

    2014-05-01

    Newly developed hypertext transfer protocol (HTTP)-based video streaming technologies enable flexible rate-adaptation under varying channel conditions. Accurately predicting the users' quality of experience (QoE) for rate-adaptive HTTP video streams is thus critical to achieve efficiency. An important aspect of understanding and modeling QoE is predicting the up-to-the-moment subjective quality of a video as it is played, which is difficult due to hysteresis effects and nonlinearities in human behavioral responses. This paper presents a Hammerstein-Wiener model for predicting the time-varying subjective quality (TVSQ) of rate-adaptive videos. To collect data for model parameterization and validation, a database of longer duration videos with time-varying distortions was built and the TVSQs of the videos were measured in a large-scale subjective study. The proposed method is able to reliably predict the TVSQ of rate adaptive videos. Since the Hammerstein-Wiener model has a very simple structure, the proposed method is suitable for online TVSQ prediction in HTTP-based streaming.

  15. Critical shear stress for erosion of cohesive soils subjected to temperatures typical of wildfires

    Science.gov (United States)

    Moody, J.A.; Dungan, Smith J.; Ragan, B.W.

    2005-01-01

    [1] Increased erosion is a well-known response after wildfire. To predict and to model erosion on a landscape scale requires knowledge of the critical shear stress for the initiation of motion of soil particles. As this soil property is temperature-dependent, a quantitative relation between critical shear stress and the temperatures to which the soils have been subjected during a wildfire is required. In this study the critical shear stress was measured in a recirculating flume using samples of forest soil exposed to different temperatures (40??-550??C) for 1 hour. Results were obtained for four replicates of soils derived from three different types of parent material (granitic bedrock, sandstone, and volcanic tuffs). In general, the relation between critical shear stress and temperature can be separated into three different temperature ranges (275??C), which are similar to those for water repellency and temperature. The critical shear stress was most variable (1.0-2.0 N m-2) for temperatures 2.0 N m-2) between 175?? and 275??C, and was essentially constant (0.5-0.8 N m-2) for temperatures >275??C. The changes in critical shear stress with temperature were found to be essentially independent of soil type and suggest that erosion processes in burned watersheds can be modeled more simply than erosion processes in unburned watersheds. Wildfire reduces the spatial variability of soil erodibility associated with unburned watersheds by eliminating the complex effects of vegetation in protecting soils and by reducing the range of cohesion associated with different types of unburned soils. Our results indicate that modeling the erosional response after a wildfire depends primarily on determining the spatial distribution of the maximum soil temperatures that were reached during the wildfire. Copyright 2005 by the American Geophysical Union.

  16. Accelerated reliability testing of highly aligned single-walled carbon nanotube networks subjected to DC electrical stressing.

    Science.gov (United States)

    Strus, Mark C; Chiaramonti, Ann N; Kim, Young Lae; Jung, Yung Joon; Keller, Robert R

    2011-07-01

    We investigate the electrical reliability of nanoscale lines of highly aligned, networked, metallic/semiconducting single-walled carbon nanotubes (SWCNTs) fabricated through a template-based fluidic assembly process. We find that these SWCNT networks can withstand DC current densities larger than 10 MA cm(-2) for several hours and, in some cases, several days. We develop test methods that show that the degradation rate, failure predictability and total device lifetime can be linked to the initial resistance. Scanning electron and transmission electron microscopy suggest that fabrication variability plays a critical role in the rate of degradation, and we offer an empirical method of quickly determining the long-term performance of a network. We find that well-fabricated lines subject to constant electrical stress show a linear accumulation of damage reminiscent of electromigration in metallic interconnects, and we explore the underlying physical mechanisms that could cause such behavior.

  17. Exogenous melatonin improves corn (Zea mays L.) embryo proteome in seeds subjected to chilling stress.

    Science.gov (United States)

    Kołodziejczyk, Izabela; Dzitko, Katarzyna; Szewczyk, Rafał; Posmyk, Małgorzata M

    2016-04-01

    Melatonin (MEL; N-acetyl-5-methoxytryptamine) plays an important role in plant stress defense. Various plant species rich in this indoleamine have shown a higher capacity for stress tolerance. Moreover, it has great potential for plant biostimulation, is biodegradable and non-toxic for the environment. All this indicates that our concept of seed enrichment with exogenous MEL is justified. This work concerns the effects of corn (Zea mays L.) seed pre-sowing treatments supplemented with MEL. Non-treated seeds (nt), and those hydroprimed with water (H) or with MEL solutions 50 and 500 μM (HMel50, HMel500) were compared. Positive effects of seed priming are particularly apparent during germination under suboptimal conditions. The impact of MEL applied by priming on seed protein profiles during imbibition/germination at low temperature has not been investigated to date. In order to identify changes in the corn seed proteome after applying hydropriming techniques, purified protein extracts of chilling stressed seed embryos (14 days, 5°C) were separated by two-dimensional electrophoresis. Then proteome maps were graphically and statistically compared and selected protein spots were qualitatively analyzed using mass spectrometry techniques and identified. This study aimed to analyze the priming-induced changes in maize embryo proteome and at identifying priming-associated and MEL-associated proteins in maize seeds subjected to chilling. We attempt to explain how MEL expands plant capacity for stress tolerance. Copyright © 2016 Elsevier GmbH. All rights reserved.

  18. Double- and Triple-Duty Caregiving Men: An Examination of Subjective Stress and Perceived Schedule Control.

    Science.gov (United States)

    DePasquale, Nicole; Zarit, Steven H; Mogle, Jacqueline; Moen, Phyllis; Hammer, Leslie B; Almeida, David M

    2018-04-01

    Based on the stress process model of family caregiving, this study examined subjective stress appraisals and perceived schedule control among men employed in the long-term care industry (workplace-only caregivers) who concurrently occupied unpaid family caregiving roles for children (double-duty child caregivers), older adults (double-duty elder caregivers), and both children and older adults (triple-duty caregivers). Survey responses from 123 men working in nursing home facilities in the United States were analyzed using multiple linear regression models. Results indicated that workplace-only and double- and triple-duty caregivers' appraised primary stress similarly. However, several differences emerged with respect to secondary role strains, specifically work-family conflict, emotional exhaustion, and turnover intentions. Schedule control also constituted a stress buffer for double- and triple-duty caregivers, particularly among double-duty elder caregivers. These findings contribute to the scarce literature on double- and triple-duty caregiving men and have practical implications for recruitment and retention strategies in the health care industry.

  19. Microcrack Evolution and Associated Deformation and Strength Properties of Sandstone Samples Subjected to Various Strain Rates

    Directory of Open Access Journals (Sweden)

    Chong-Feng Chen

    2018-05-01

    Full Text Available The evolution of micro-cracks in rocks under different strain rates is of great importance for a better understanding of the mechanical properties of rocks under complex stress states. In the present study, a series of tests were carried out under various strain rates, ranging from creep tests to intermediate strain rate tests, so as to observe the evolution of micro-cracks in rock and to investigate the influence of the strain rate on the deformation and strength properties of rocks. Thin sections from rock samples at pre- and post-failure were compared and analyzed at the microscale using an optical microscope. The results demonstrate that the main crack propagation in the rock is intergranular at a creep strain rate and transgranular at a higher strain rate. However, intergranular cracks appear mainly around the quartz and most of the punctured grains are quartz. Furthermore, the intergranular and transgranular cracks exhibit large differences in the different loading directions. In addition, uniaxial compressive tests were conducted on the unbroken rock samples in the creep tests. A comparison of the stress–strain curves of the creep tests and the intermediate strain rate tests indicate that Young’s modulus and the peak strength increase with the strain rate. In addition, more deformation energy is released by the generation of the transgranular cracks than the generation of the intergranular cracks. This study illustrates that the conspicuous crack evolution under different strain rates helps to understand the crack development on a microscale, and explains the relationship between the micro- and macro-behaviors of rock before the collapse under different strain rates.

  20. Prediction of thermal and mechanical stress-strain responses of TMC's subjected to complex TMF histories

    Science.gov (United States)

    Johnson, W. S.; Mirdamadi, M.

    1994-01-01

    This paper presents an experimental and analytical evaluation of cross-plied laminates of Ti-15V-3Cr-3Al-3Sn (Ti-15-3) matrix reinforced with continuous silicon-carbide fibers (SCS-6) subjected to a complex TMF loading profile. Thermomechanical fatigue test techniques were developed to conduct a simulation of a generic hypersonic flight profile. A micromechanical analysis was used. The analysis predicts the stress-strain response of the laminate and of the constituents in each ply during thermal and mechanical cycling by using only constituent properties as input. The fiber was modeled as elastic with transverse orthotropic and temperature-dependent properties. The matrix was modeled using a thermoviscoplastic constitutive relation. The fiber transverse modulus was reduced in the analysis to simulate the fiber-matrix interface failures. Excellent correlation was found between measured and predicted laminate stress-strain response due to generic hypersonic flight profile when fiber debonding was modeled.

  1. Predictive maintenance policy for a gradually deteriorating system subject to stress

    Energy Technology Data Exchange (ETDEWEB)

    Deloux, E. [IRCCyN/Ecole des Mines de Nantes, Nantes (France); Castanier, B. [IRCCyN/Ecole des Mines de Nantes, Nantes (France)], E-mail: bruno.castanier@emn.fr; Berenguer, C. [Universite de Technologie de Troyes/CNRS, Troyes (France)

    2009-02-15

    This paper deals with a predictive maintenance policy for a continuously deteriorating system subject to stress. We consider a system with two failure mechanisms which are, respectively, due to an excessive deterioration level and a shock. To optimize the maintenance policy of the system, an approach combining statistical process control (SPC) and condition-based maintenance (CBM) is proposed. CBM policy is used to inspect and replace the system according to the observed deterioration level. SPC is used to monitor the stress covariate. In order to assess the performance of the proposed maintenance policy and to minimize the long-run expected maintenance cost per unit of time, a mathematical model for the maintained system cost is derived. Analysis based on numerical results are conducted to highlight the properties of the proposed maintenance policy in respect to the different maintenance parameters.

  2. Analysis of stresses on buried pipeline subjected to landslide based on numerical simulation and regression analysis

    Energy Technology Data Exchange (ETDEWEB)

    Han, Bing; Jing, Hongyuan; Liu, Jianping; Wu, Zhangzhong [PetroChina Pipeline RandD Center, Langfang, Hebei (China); Hao, Jianbin [School of Petroleum Engineering, Southwest Petroleum University, Chengdu, Sichuan (China)

    2010-07-01

    Landslides have a serious impact on the integrity of oil and gas pipelines in the tough terrain of Western China. This paper introduces a solving method of axial stress, which uses numerical simulation and regression analysis for the pipelines subjected to landslides. Numerical simulation is performed to analyze the change regularity of pipe stresses for the five vulnerability assessment indexes, which are: the distance between pipeline and landslide tail; the thickness of landslide; the inclination angle of landslide; the pipeline length passing through landslide; and the buried depth of pipeline. A pipeline passing through a certain landslide in southwest China was selected as an example to verify the feasibility and effectiveness of this method. This method has practical applicability, but it would need large numbers of examples to better verify its reliability and should be modified accordingly. Also, it only considers the case where the direction of the pipeline is perpendicular to the primary slip direction of the landslide.

  3. Predictive maintenance policy for a gradually deteriorating system subject to stress

    International Nuclear Information System (INIS)

    Deloux, E.; Castanier, B.; Berenguer, C.

    2009-01-01

    This paper deals with a predictive maintenance policy for a continuously deteriorating system subject to stress. We consider a system with two failure mechanisms which are, respectively, due to an excessive deterioration level and a shock. To optimize the maintenance policy of the system, an approach combining statistical process control (SPC) and condition-based maintenance (CBM) is proposed. CBM policy is used to inspect and replace the system according to the observed deterioration level. SPC is used to monitor the stress covariate. In order to assess the performance of the proposed maintenance policy and to minimize the long-run expected maintenance cost per unit of time, a mathematical model for the maintained system cost is derived. Analysis based on numerical results are conducted to highlight the properties of the proposed maintenance policy in respect to the different maintenance parameters

  4. Effect of mental stress on plasma homovanillic acid in healthy human subjects.

    Science.gov (United States)

    Sumiyoshi, T; Yotsutsuji, T; Kurachi, M; Itoh, H; Kurokawa, K; Saitoh, O

    1998-07-01

    Plasma levels of homovanillic acid (pHVA) have been suggested to provide a measure of dopaminergic activity in the central nervous system. The present study investigated the effect of mental stress by the Kraepelin test, a test of continuous arithmetic addition of single-digit figures for 30 min, on pHVA levels in 13 male psychiatrically normal healthy volunteers. Following an overnight fast and restricted physical activity, plasma samples were collected immediately before and after the administration of the Kraepelin test. Plasma HVA levels following the administration of the Kraepelin test were significantly lower than the pretest pHVA levels. The percent change in pHVA levels by the Kraepelin test positively correlated with pretest pHVA levels. The observed reduction in pHVA levels by mental stress in normal subjects may reflect some aspects of a dopamine-dependent restitutive system in the brain.

  5. Usefulness of an accelerated transoesophageal stress echocardiography in the preoperative evaluation of high risk severely obese subjects awaiting bariatric surgery

    Directory of Open Access Journals (Sweden)

    Tessier Michel

    2010-07-01

    Full Text Available Abstract Background Severe obesity is associated with an increased risk of coronary artery disease (CAD. Bariatric surgery is an effective procedure for long term weight management as well as reduction of comorbidities. Preoperative evaluation of cardiac operative risk may often be necessary but unfortunately standard imaging techniques are often suboptimal in these subjects. The purpose of this study was to demonstrate the feasibility, safety and utility of transesophageal dobutamine stress echocardiography (TE-DSE using an adapted accelerated dobutamine infusion protocol in severely obese subjects with comorbidities being evaluated for bariatric surgery for assessing the presence of myocardial ischemia. Methods Subjects with severe obesity [body mass index (BMI >40 kg/m2] with known or suspected CAD and being evaluated for bariatric surgery were recruited. Results Twenty subjects (9M/11F, aged 50 ± 8 years (mean ± SD, weighing 141 ± 21 kg and with a BMI of 50 ± 5 kg/m2 were enrolled in the study and underwent a TE-DSE. The accelerated dobutamine infusion protocol used was well tolerated. Eighteen (90% subjects reached their target heart rate with a mean intubation time of 13 ± 4 minutes. Mean dobutamine dose was 31.5 ± 9.9 ug/kg/min while mean atropine dose was 0.5 ± 0.3 mg. TE-DSE was well tolerated by all subjects without complications including no significant arrhythmia, hypotension or reduction in blood arterial saturation. Two subjects had abnormal TE-DSE suggestive of myocardial ischemia. All patients underwent bariatric surgery with no documented cardiovascular complications. Conclusions TE-DSE using an accelerated infusion protocol is a safe and well tolerated imaging technique for the evaluation of suspected myocardial ischemia and cardiac operative risk in severely obese patients awaiting bariatric surgery. Moreover, the absence of myocardial ischemia on TE-DSE correlates well with a low operative risk of cardiac event.

  6. A relation between calculated human body exergy consumption rate and subjectively assessed thermal sensation

    DEFF Research Database (Denmark)

    Simone, Angela; Kolarik, Jakub; Iwamatsu, Toshiya

    2011-01-01

    occupants, it is reasonable to consider both the exergy flows in building and those within the human body. Until now, no data have been available on the relation between human-body exergy consumption rates and subjectively assessed thermal sensation. The objective of the present work was to relate thermal...... sensation data, from earlier thermal comfort studies, to calculated human-body exergy consumption rates. The results show that the minimum human body exergy consumption rate is associated with thermal sensation votes close to thermal neutrality, tending to the slightly cool side of thermal sensation....... Generally, the relationship between air temperature and the exergy consumption rate, as a first approximation, shows an increasing trend. Taking account of both convective and radiative heat exchange between the human body and the surrounding environment by using the calculated operative temperature, exergy...

  7. Assessment of potential Rio Grande do Norte, Brazil, clays when subjected to high rates of heating

    International Nuclear Information System (INIS)

    Filgueira, R.L.; Pereira, L.M.; Dutra, R.P.S.; Nascimento, R.M.

    2009-01-01

    In this work we study three clays of the state of Rio Grande do Norte, Brazil, to evaluate the potential them when subjected to high rates of heating. The samples were formed by pressing and subject to rates of 5 deg C / min, 10 deg C / min and 15 deg C / min, with temperature of 950 deg C. This study determined the technological properties of the samples. The mineralogical composition was identified by X-ray diffraction. The chemical composition was determined by Xray fluorescence. The Atterberg limits, were used to classify the samples on the plasticity. Were also performed: dilatometry, size analysis and scanning electron microscopy. The examination of the processing variables and the intrinsic characteristics of each material indicates that the RX clay showed the best results for the manufacture of blocks and tiles. The techniques used in this study were efficient and the initial objectives were achieved. (author)

  8. Testosterone potentiates the hypoxic ventilatory response of adult male rats subjected to neonatal stress.

    Science.gov (United States)

    Fournier, Sébastien; Gulemetova, Roumiana; Joseph, Vincent; Kinkead, Richard

    2014-05-01

    Neonatal stress disrupts development of homeostatic systems. During adulthood, male rats subjected to neonatal maternal separation (NMS) are hypertensive and show a larger hypoxic ventilatory response (HVR), with greater respiratory instability during sleep. Neonatal stress also affects sex hormone secretion; hypoxia increases circulating testosterone of NMS (but not control) male rats. Given that these effects of NMS are not observed in females, we tested the hypothesis that testosterone elevation is necessary for the stress-related increase of the HVR in adult male rats. Pups subjected to NMS were placed in an incubator for 3 h per day from postnatal day 3 to 12. Control pups remained undisturbed. Rats were reared until adulthood, and the HVR was measured by plethysmography (fractional inspired O2 = 0.12, for 20 min). We used gonadectomy to evaluate the effects of reducing testosterone on the HVR. Gonadectomy had no effect on the HVR of control animals but reduced that of NMS animals below control levels. Immunohistochemistry was used to quantify androgen receptors in brainstem areas involved in the HVR. Androgen receptor expression was generally greater in NMS rats than in control rats; the most significant increase was noted in the caudal region of the nucleus tractus solitarii. We conclude that the abnormal regulation of testosterone is important in stress-related augmentation of the HVR. The greater number of androgen receptors within the brainstem may explain why NMS rats are more sensitive to testosterone withdrawal. Based on the similarities of the cardiorespiratory phenotype of NMS rats and patients suffering from sleep-disordered breathing, these results provide new insight into its pathophysiology, especially sex-based differences in its prevalence. © 2014 The Authors. Experimental Physiology © 2014 The Physiological Society.

  9. A single dose of dark chocolate increases parasympathetic modulation and heart rate variability in healthy subjects

    Directory of Open Access Journals (Sweden)

    Ana Amélia Machado DUARTE

    Full Text Available ABSTRACT Objective: The aim of this study was to investigate the acute effect of a single dose of dark chocolate (70% cocoa on blood pressure and heart rate variability. Methods: Thirty-one healthy subjects (aged 18-25 years; both sexes were divided into two groups: 10 subjects in the white chocolate (7.4 g group and 21 in the dark chocolate (10 g group; measurements were performed at the university's physiology lab. An electrocardiogram measured the sympathovagal balance by spectral and symbolic analysis. Results: A single dose of dark chocolate significantly reduced systolic blood pressure and heart rate. After consuming 10 g of dark chocolate, significant increases were observed for heart rate variability, standard deviation of RR intervals standard deviation of all NN intervals, square root of the mean squared differences between adjacent normal RR intervals root mean square of successive differences, and an increase in the high frequency component in absolute values, representing the parasympathetic modulation. Conclusion: In conclusion the importance of our results lies in the magnitude of the response provoked by a single dose of cocoa. Just 10 g of cocoa triggered a significant increase in parasympathetic modulation and heart rate variability. These combined effects can potentially increase life expectancy because a reduction in heart rate variability is associated with several cardiovascular diseases and higher mortality.

  10. Textured insoles reduce vertical loading rate and increase subjective plantar sensation in overground running.

    Science.gov (United States)

    Wilkinson, Michael; Ewen, Alistair; Caplan, Nicholas; O'leary, David; Smith, Neil; Stoneham, Richard; Saxby, Lee

    2018-05-01

    The effect of textured insoles on kinetics and kinematics of overground running was assessed. 16 male injury-free-recreational runners attended a single visit (age 23 ± 5 yrs; stature 1.78 ± 0.06 m; mass 72.6 ± 9.2 kg). Overground 15-m runs were completed in flat, canvas plimsolls both with and without textured insoles at self-selected velocity on an indoor track in an order that was balanced among participants. Average vertical loading rate and peak vertical force (F peak ) were captured by force platforms. Video footage was digitised for sagittal plane hip, knee and ankle angles at foot strike and mid stance. Velocity, stride rate and length and contact and flight time were determined. Subjectively rated plantar sensation was recorded by visual scale. 95% confidence intervals estimated mean differences. Smallest worthwhile change in loading rate was defined as standardised reduction of 0.54 from a previous comparison of injured versus non-injured runners. Loading rate decreased (-25 to -9.3 BW s -1 ; 60% likely beneficial reduction) and plantar sensation was increased (46-58 mm) with the insole. F peak (-0.1 to 0.14 BW) and velocity (-0.02 to 0.06 m s -1 ) were similar. Stride length, flight and contact time were lower (-0.13 to -0.01 m; -0.02 to-0.01 s; -0.016 to -0.006 s) and stride rate was higher (0.01-0.07 steps s -1 ) with insoles. Textured insoles elicited an acute, meaningful decrease in vertical loading rate in short distance, overground running and were associated with subjectively increased plantar sensation. Reduced vertical loading rate could be explained by altered stride characteristics.

  11. Long-term effect of yogic practices on diurnal metabolic rates of healthy subjects

    Directory of Open Access Journals (Sweden)

    Chaya M

    2008-01-01

    Full Text Available Background: The metabolic rate is an indicator of autonomic activity. Reduced sympathetic arousal probably resulting in hypometabolic states has been reported in several yogic studies. Aim: The main objective of this study was to assess the effect of yoga training on diurnal metabolic rates in yoga practitioners at two different times of the day (at 6 a.m. and 9 p.m.. Methods and Material: Eighty eight healthy volunteers were selected and their metabolic rates assessed at 6 a.m. and 9 p.m. using an indirect calorimeter at a yoga school in Bangalore, India. Results and conclusions: The results show that the average metabolic rate of the yoga group was 12% lower than that of the non-yoga group ( P < 0.001 measured at 9 p.m. and 16% lower at 6 a.m. ( P < 0.001. The 9 p.m. metabolic rates of the yoga group were almost equal to their predicted basal metabolic rates (BMRs whereas the metabolic rate was significantly higher than the predicted BMR for the non-yoga group. The 6 a.m. metabolic rate was comparable to their predicted BMR in the non-yoga group whereas it was much lower in the yoga group ( P < 0.001. The lower metabolic rates in the yoga group at 6 a.m. and 9 p.m. may be due to coping strategies for day-to-day stress, decreased sympathetic nervous system activity and probably, a stable autonomic nervous system response (to different stressors achieved due to training in yoga.

  12. Long-term effect of yogic practices on diurnal metabolic rates of healthy subjects

    Directory of Open Access Journals (Sweden)

    Chaya M

    2008-01-01

    Full Text Available Background : The metabolic rate is an indicator of autonomic activity. Reduced sympathetic arousal probably resulting in hypometabolic states has been reported in several yogic studies. Aim : The main objective of this study was to assess the effect of yoga training on diurnal metabolic rates in yoga practitioners at two different times of the day (at 6 a.m. and 9 p.m.. Materials and Methods : Eighty eight healthy volunteers were selected and their metabolic rates assessed at 6 a.m. and 9 p.m. using an indirect calorimeter at a yoga school in Bangalore, India. Results and conclusions: The results show that the average metabolic rate of the yoga group was 12% lower than that of the non-yoga group ( P < 0.001 measured at 9 p.m. and 16% lower at 6 a.m. ( P < 0.001. The 9 p.m. metabolic rates of the yoga group were almost equal to their predicted basal metabolic rates (BMRs whereas the metabolic rate was significantly higher than the predicted BMR for the non-yoga group. The 6 a.m. metabolic rate was comparable to their predicted BMR in the non-yoga group whereas it was much lower in the yoga group ( P < 0.001. The lower metabolic rates in the yoga group at 6 a.m. and 9 p.m. may be due to coping strategies for day-to-day stress, decreased sympathetic nervous system activity and probably, a stable autonomic nervous system response (to different stressors achieved due to training in yoga.

  13. Age-related mechanism and its relationship with secondary metabolism and abscisic acid in Aristotelia chilensis plants subjected to drought stress.

    Science.gov (United States)

    González-Villagra, Jorge; Rodrigues-Salvador, Acácio; Nunes-Nesi, Adriano; Cohen, Jerry D; Reyes-Díaz, Marjorie M

    2018-03-01

    Drought stress is the most important stress factor for plants, being the main cause of agricultural crop loss in the world. Plants have developed complex mechanisms for preventing water loss and oxidative stress such as synthesis of abscisic acid (ABA) and non-enzymatic antioxidant compounds such as anthocyanins, which might help plants to cope with abiotic stress as antioxidants and for scavenging reactive oxygen species. A. chilensis (Mol.) is a pioneer species, colonizing and growing on stressed and disturbed environments. In this research, an integrated analysis of secondary metabolism in Aristotelia chilensis was done to relate ABA effects on anthocyanins biosynthesis, by comparing between young and fully-expanded leaves under drought stress. Plants were subjected to drought stress for 20 days, and physiological, biochemical, and molecular analyses were performed. The relative growth rate and plant water status were reduced in stressed plants, with young leaves significantly more affected than fully-expanded leaves beginning from the 5th day of drought stress. A. chilensis plants increased their ABA and total anthocyanin content and showed upregulation of gene expression when they were subjected to severe drought (day 20), with these effects being higher in fully-expanded leaves. Multivariate analysis indicated a significant positive correlation between transcript levels for NCED1 (9-cis-epoxycarotenoid dioxygenase) and UFGT (UDP glucose: flavonoid-3-O-glucosyltransferase) with ABA and total anthocyanin, respectively. Thus, this research provides a more comprehensive analysis of the mechanisms that allow plants to cope with drought stress. This is highlighted by the differences between young and fully-expanded leaves, showing different sensibility to stress due to their ability to synthesize anthocyanins. In addition, this ability to synthesize different and high amounts of anthocyanins could be related to higher NCED1 and MYB expression and ABA levels

  14. Stress-sensitive tissue regeneration in viscoelastic biomaterials subjected to modulated tensile strain.

    Science.gov (United States)

    Belfiore, Laurence A; Floren, Michael L; Paulino, Alexandre T; Belfiore, Carol J

    2011-09-01

    This research contribution addresses the mechanochemistry of intra-tissue mass transfer for nutrients, oxygen, growth factors, and other essential ingredients that anchorage-dependent cells require for successful proliferation on biocompatible surfaces. The unsteady state reaction-diffusion equation (i.e., modified diffusion equation) is solved according to the von Kármán-Pohlhausen integral method of boundary layer analysis when nutrient consumption and tissue regeneration are stimulated by harmonically imposed stress. The mass balance with diffusion and stress-sensitive kinetics represents a rare example where the Damköhler and Deborah numbers appear together in an effort to simulate the development of mass transfer boundary layers in porous viscoelastic biomaterials. The Boltzmann superposition integral is employed to calculate time-dependent strain in terms of the real and imaginary components of dynamic compliance for viscoelastic solids that transmit harmonic excitation to anchorage-dependent cells. Rates of nutrient consumption under stress-free conditions are described by third-order kinetics which include local mass densities of nutrients, oxygen, and attached cells that maintain dynamic equilibrium with active protein sites in the porous matrix. Thinner nutrient mass transfer boundary layers are stabilized at shorter dimensionless diffusion times when the stress-free intra-tissue Damköhler number increases above its initial-condition-sensitive critical value. The critical stress-sensitive intra-tissue Damköhler number, above which it is necessary to consider the effect of harmonic strain on nutrient consumption and tissue regeneration, is proportional to the Deborah number and corresponds to a larger fraction of the stress-free intra-tissue Damköhler number in rigid biomaterials. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Nature contact and organizational support during office working hours: Benefits relating to stress reduction, subjective health complaints, and sick leave.

    Science.gov (United States)

    Bjørnstad, Siv; Patil, Grete G; Raanaas, Ruth K

    2015-01-01

    Improving social support, and providing nature contact at work are potential health promoting workplace interventions. The objective was to investigate whether nature contact at work is associated with employee's health and participation, and to study whether the possible associations between nature contact and health can be explained by perceived organizational support. Data were collected through a web-based, cross-sectional survey of employees in seven public and private office workplaces in Norway (n = 707, 40% response rate). Multiple linear and logistic regression analysis were performed on 565 participants fulfilling inclusion criteria. A greater amount of indoor nature contact at work was significantly associated with less job stress (B = -0.18, CI = -0.318 to -0.042), fewer subjective health complaints (B = -0.278, CI = -0.445 to -0.112) and less sickness absence (B = -0.061, CI = -0.009 to -0.002). Perceived organizational support mediated the associations between indoor nature contact and job stress and sickness absence, and partly mediated the association with subjective health complaints. Outdoor nature contact showed no reliable association with the outcomes in this study. Extending nature contact in the physical work environment in offices, can add to the variety of possible health-promoting workplace interventions, primarily since it influences the social climate on the workplace.

  16. Instantaneous Metabolic Cost of Walking: Joint-Space Dynamic Model with Subject-Specific Heat Rate.

    Directory of Open Access Journals (Sweden)

    Dustyn Roberts

    Full Text Available A subject-specific model of instantaneous cost of transport (ICOT is introduced from the joint-space formulation of metabolic energy expenditure using the laws of thermodynamics and the principles of multibody system dynamics. Work and heat are formulated in generalized coordinates as functions of joint kinematic and dynamic variables. Generalized heat rates mapped from muscle energetics are estimated from experimental walking metabolic data for the whole body, including upper-body and bilateral data synchronization. Identified subject-specific energetic parameters-mass, height, (estimated maximum oxygen uptake, and (estimated maximum joint torques-are incorporated into the heat rate, as opposed to the traditional in vitro and subject-invariant muscle parameters. The total model metabolic energy expenditure values are within 5.7 ± 4.6% error of the measured values with strong (R2 > 0.90 inter- and intra-subject correlations. The model reliably predicts the characteristic convexity and magnitudes (0.326-0.348 of the experimental total COT (0.311-0.358 across different subjects and speeds. The ICOT as a function of time provides insights into gait energetic causes and effects (e.g., normalized comparison and sensitivity with respect to walking speed and phase-specific COT, which are unavailable from conventional metabolic measurements or muscle models. Using the joint-space variables from commonly measured or simulated data, the models enable real-time and phase-specific evaluations of transient or non-periodic general tasks that use a range of (aerobic energy pathway similar to that of steady-state walking.

  17. Posttraumatic Stress Disorder, Quality of Life, and the Subjective Experience in Liver Transplant Recipients.

    Science.gov (United States)

    Paslakis, Georgios; Beckmann, Mingo; Beckebaum, Susanne; Klein, Christian; Gräf, Jan; Erim, Yesim

    2018-03-01

    A high prevalence of posttraumatic stress disorder (PTSD) symptoms among transplant recipients has been associated with a low adherence to treatment and poor survival. It is crucial to detect and prevent the development of posttraumatic stress in transplant settings. We examined the prevalence of posttraumatic stress symptoms in 3 liver transplant recipients by means of the Essen Trauma Inventory (ETI), a self-report questionnaire. The Short Form-36 was used to assess the perceived health-related quality of life. Patients were asked to indicate the most traumatic events within the context of the liver transplantation procedure. Five patients (4.9%) fulfilled the criteria for PTSD related to liver disease or transplantation (ETI score greater than 27). In these patients, diagnosis was confirmed by a structured clinical interview. Fourteen (13.6%) patients had a partial PTSD with the ETI score less than 27 and greater than 16. Posttraumatic stress symptoms were significantly associated with perceived poor physical and mental health-related quality of life. Patients reported that the physicians' disclosure of diagnosis was experienced as traumatic, followed by treatment in an intensive care unit and the liver transplantation itself. The ETI resulted in prevalence rates for PTSD comparable to previous studies in liver transplantation settings. Medical professionals requested additional training in how to deliver severe diagnoses to patients.

  18. The clinical usefulness of myocardial thallium-201 washout rate after exercise stress

    International Nuclear Information System (INIS)

    Iwasaki, Tsutomu; Takino, Yutaka; Sakurai, Fumio

    1989-01-01

    Myocardial Tl-201 Washout rates (WORs) after exercise stress were measured in 15 normal subjects and 67 patients with coronary artery disease (CAD) or chest pain syndrome and the usefulness of WOR for the detection of CAD was studied. Myocardial tomograms were obtained both immediately after exercise and 3 hours later using a rotating gamma camera in 15 normal subjects and 67 patients. After low-pass filtering, images were reconstructed into short-axis, horizontal long-axis and vertical long-axis tomograms and visually interpreted. By using short-axis tomograms, left ventricle WORs were expressed as circumferential profile curves at the apex, center and base of the ventricle. Lower normal limits of the WOR were set at 2 SDs from the mean of the normal subjects. The combination of visual interpretation of SPECT with WOR increased the sensitivity of detection of CAD from 8.3% to 66.7% in patients with three-vessel CAD without losing specificity. WOR after exercise stress is believed to be a useful method of detecting multivessel CAD. (author)

  19. Prognostic value of ambulatory heart rate revisited in 6928 subjects from 6 populations

    DEFF Research Database (Denmark)

    Hansen, Tine Willum; Thijs, Lutgarde; Staessen, Jan A.

    2008-01-01

    The evidence relating mortality and morbidity to heart rate remains inconsistent. We performed 24-hour ambulatory blood pressure monitoring in 6928 subjects (not on beta-blockers; mean age: 56.2 years; 46.5% women) enrolled in prospective population studies in Denmark, Belgium, Japan, Sweden......, Uruguay, and China. We computed standardized hazard ratios for heart rate, while stratifying for cohort, and adjusting for blood pressure and other cardiovascular risk factors. Over 9.6 years (median), 850, 325, and 493 deaths accrued for total, cardiovascular, and noncardiovascular mortality......, respectively. The incidence of fatal combined with nonfatal end points was 805, 363, 439, and 324 for cardiovascular, stroke, cardiac, and coronary events, respectively. Twenty-four-hour heart rate predicted total (hazard ratio: 1.15) and noncardiovascular (hazard ratio: 1.18) mortality but not cardiovascular...

  20. Do physiological and pathological stresses produce different changes in heart rate variability?

    Directory of Open Access Journals (Sweden)

    Andrea eBravi

    2013-07-01

    Full Text Available Although physiological (e.g. exercise and pathological (e.g. infection stress affecting the cardiovascular system have both been documented to be associated with a reduction in overall heart rate variability (HRV, it remains unclear if loss of HRV is ubiquitously similar across different domains of variability analysis or if distinct patterns of altered HRV exist depending on the stressor. Using Continuous Individualized Multiorgan Variability Analysis (CIMVATM software, heart rate (HR and four selected measures of variability were measured over time (windowed analysis from two datasets, a set (n=13 of patients who developed systemic infection (i.e. sepsis after bone marrow transplant, and a matched set of healthy subjects undergoing physical exercise under controlled conditions. HR and the four HRV measures showed similar trends in both sepsis and exercise. The comparison through Wilcoxon sign-rank test of the levels of variability at baseline and during the stress (i.e. exercise or after days of sepsis development showed similar changes, except for LF/HF, ratio of power at low and high frequencies (associated with sympathovagal modulation, which was affected by exercise but did not show any change during sepsis. Furthermore, HRV measures during sepsis showed a lower level of correlation with each other, as compared to HRV during exercise. In conclusion, this exploratory study highlights similar responses during both exercise and infection, with differences in terms of correlation and inter-subject fluctuations, whose physiologic significance merits further investigation.

  1. Reinforced concrete membrane elements subjected to reversed cyclic in-plane shear stress

    International Nuclear Information System (INIS)

    Ohmori, N.; Tsubota, H.; Inoue, N.; Watanabe, S.; Kurihara, K.

    1987-01-01

    The response of reinforced concrete elements subjected to reversed cyclic in-plane shear stresses can be predicted by an analytical model, which considers equilibrium, compatibility and stress-strain relationships including hysteresis loop of unloading and reloading stages all expressed in terms of average stresses and average strains. The analytical results show that the dominant hysteretic behaviours in regard to decrease of stiffness during unloading, successive slip phenomena and restoration of compressive stiffness at the reloading stages are well simulated analytically. The results agree quite well with the observed behaviours. As for the envelope curve of the hysteretic response there remain the discrepancies that the stiffness and ultimate strength are a bit larger than the observed results, especially in the case of a panel with a large reinforcement ratio. Such descrepancies are also found in the predicted results of monotonic loading and more precise studies are necessary to evaluate more accurate envelope curves under not only reversed cyclic loading but also monotonic loading. (orig./HP)

  2. The effect of texture, heat treatment and elongation rate on stress corrosion cracking in irradiated zircaloy

    International Nuclear Information System (INIS)

    Pettersson, K.; Stany, W.; Hellstrand, E.

    1979-03-01

    Irradiated zircaloy samples with different textures and heat treatments have been tested concerning stress corrosion. Irradiated samples of Zr-1Nb, pure Zr and beta quenched zircaloy have also been investigated. Stress-relieve annealled zircaloy is even after irradiation more sensitive to stress corrosion than recrystallized zircaloy. Zr-1Nb and beta quenched zircaloy are much more sinsitive to stress corrosion than the samples with different textures. As a rule irradiated zircaloy is sensitive to stress corrosion at stresses far below the yield point. The breaking stress decreases with the elongation rate. The extension of cracks is much faster in irradiated zircaloy than in unirradiated zircaloy. There is no simple failure criterium for irradiated zircaloy. However for a certain stress and a certain elongation rate the probability for a failure before this stress is reached with a constant elongation rate can be given. (E.R.)

  3. A relation between calculated human body exergy consumption rate and subjectively assessed thermal sensation

    Energy Technology Data Exchange (ETDEWEB)

    Simone, Angela; Kolarik, Jakub; Olesen, Bjarne W. [ICIEE/BYG, Technical University of Denmark (Denmark); Iwamatsu, Toshiya [Faculty of Urban Environmental Science, Tokyo Metropolitan University (Japan); Asada, Hideo [Architech Consulting Co., Tokyo (Japan); Dovjak, Mateja [Faculty of Civil and Geodetic Engineering, University of Ljubljana (Slovenia); Schellen, Lisje [Eindhoven University of Technology, Faculty of Architecture Building and Planning (Netherlands); Shukuya, Masanori [Laboratory of Building Environment, Tokyo City University, Yokohama (Japan)

    2011-01-15

    Application of the exergy concept to research on the built environment is a relatively new approach. It helps to optimize climate conditioning systems so that they meet the requirements of sustainable building design. As the building should provide a healthy and comfortable environment for its occupants, it is reasonable to consider both the exergy flows in building and those within the human body. Until now, no data have been available on the relation between human-body exergy consumption rates and subjectively assessed thermal sensation. The objective of the present work was to relate thermal sensation data, from earlier thermal comfort studies, to calculated human-body exergy consumption rates. The results show that the minimum human body exergy consumption rate is associated with thermal sensation votes close to thermal neutrality, tending to the slightly cool side of thermal sensation. Generally, the relationship between air temperature and the exergy consumption rate, as a first approximation, shows an increasing trend. Taking account of both convective and radiative heat exchange between the human body and the surrounding environment by using the calculated operative temperature, exergy consumption rates increase as the operative temperature increases above 24 C or decreases below 22 C. With the data available so far, a second-order polynomial relationship between thermal sensation and the exergy consumption rate was established. (author)

  4. The relationship between bioclimatic thermal stress and subjective thermal sensation in pedestrian spaces

    Science.gov (United States)

    Pearlmutter, David; Jiao, Dixin; Garb, Yaakov

    2014-12-01

    Outdoor thermal comfort has important implications for urban planning and energy consumption in the built environment. To better understand the relation of subjective thermal experience to bioclimatic thermal stress in such contexts, this study compares micrometeorological and perceptual data from urban spaces in the hot-arid Negev region of Israel. Pedestrians reported on their thermal sensation in these spaces, whereas radiation and convection-related data were used to compute the Index of Thermal Stress (ITS) and physiologically equivalent temperature (PET). The former is a straightforward characterization of energy exchanges between the human body and its surroundings, without any conversion to an "equivalent temperature." Although the relation of ITS to subjective thermal sensation has been analyzed in the past under controlled indoor conditions, this paper offers the first analysis of this relation in an outdoor setting. ITS alone can account for nearly 60 % of the variance in pedestrians' thermal sensation under outdoor conditions, somewhat more than PET. A series of regressions with individual contextual variables and ITS identified those factors which accounted for additional variance in thermal sensation, whereas multivariate analyses indicated the considerable predictive power ( R-square = 0.74) of models including multiple contextual variables in addition to ITS. Our findings indicate that pedestrians experiencing variable outdoor conditions have a greater tolerance for incremental changes in thermal stress than has been shown previously under controlled indoor conditions, with a tapering of responses at high values of ITS. However, the thresholds of ITS corresponding to thermal "neutrality" and thermal "acceptability" are quite consistent regardless of context.

  5. Subjective Ratings of Beauty and Aesthetics: Correlations With Statistical Image Properties in Western Oil Paintings

    Science.gov (United States)

    Lehmann, Thomas; Redies, Christoph

    2017-01-01

    For centuries, oil paintings have been a major segment of the visual arts. The JenAesthetics data set consists of a large number of high-quality images of oil paintings of Western provenance from different art periods. With this database, we studied the relationship between objective image measures and subjective evaluations of the images, especially evaluations on aesthetics (defined as artistic value) and beauty (defined as individual liking). The objective measures represented low-level statistical image properties that have been associated with aesthetic value in previous research. Subjective rating scores on aesthetics and beauty correlated not only with each other but also with different combinations of the objective measures. Furthermore, we found that paintings from different art periods vary with regard to the objective measures, that is, they exhibit specific patterns of statistical image properties. In addition, clusters of participants preferred different combinations of these properties. In conclusion, the results of the present study provide evidence that statistical image properties vary between art periods and subject matters and, in addition, they correlate with the subjective evaluation of paintings by the participants. PMID:28694958

  6. Workplace violence, psychological stress, sleep quality and subjective health in Chinese doctors: a large cross-sectional study.

    Science.gov (United States)

    Sun, Tao; Gao, Lei; Li, Fujun; Shi, Yu; Xie, Fengzhe; Wang, Jinghui; Wang, Shuo; Zhang, Shue; Liu, Wenhui; Duan, Xiaojian; Liu, Xinyan; Zhang, Zhong; Li, Li; Fan, Lihua

    2017-12-07

    Workplace violence (WPV) against healthcare workers is known as violence in healthcare settings and referring to the violent acts that are directed towards doctors, nurses or other healthcare staff at work or on duty. Moreover, WPV can cause a large number of adverse outcomes. However, there is not enough evidence to test the link between exposure to WPV against doctors, psychological stress, sleep quality and health status in China. This study had three objectives: (1) to identify the incidence rate of WPV against doctors under a new classification, (2) to examine the association between exposure to WPV, psychological stress, sleep quality and subjective health of Chinese doctors and (3) to verify the partial mediating role of psychological stress. A cross-sectional online survey study. The survey was conducted among 1740 doctors in tertiary hospitals, 733 in secondary hospital and 139 in primary hospital across 30 provinces of China. A total of 3016 participants were invited. Ultimately, 2617 doctors completed valid questionnaires. The effective response rate was 86.8%. The results demonstrated that the prevalence rate of exposure to verbal abuse was the highest (76.2%), made difficulties (58.3%), smear reputation (40.8%), mobbing behaviour (40.2%), intimidation behaviour (27.6%), physical violence (24.1%) and sexual harassment (7.8%). Exposure to WPV significantly affected the psychological stress, sleep quality and self-reported health of doctors. Moreover, psychological stress partially mediated the relationship between work-related violence and health damage. In China, most doctors have encountered various WPV from patients and their relatives. The prevalence of three new types of WPV have been investigated in our study, which have been rarely mentioned in past research. A safer work environment for Chinese healthcare workers needs to be provided to minimise health threats, which is a top priority for both government and society. © Article author(s) (or

  7. Effects of air pollutants on the carbon dioxide (CO2) emission rate of human subjects

    DEFF Research Database (Denmark)

    Bako-Biro, Zsolt; Wargocki, Pawel; Wyon, David

    2004-01-01

    Several laboratory studies have shown the negative effects of emissions from typical indoor pollution sources on perceived air quality, SBS symptoms and the performance of office work. The subjects performed typical office tasks at their own pace while they were exposed for several hours to diffe...... to different air quality conditions. A re-analysis of the CO2 measurements obtained in two independent studies showed that human CO2 emission rates were affected by air quality (P......Several laboratory studies have shown the negative effects of emissions from typical indoor pollution sources on perceived air quality, SBS symptoms and the performance of office work. The subjects performed typical office tasks at their own pace while they were exposed for several hours...

  8. Local heat stress and skin blood flowmotion in subjects with familial predisposition or newly diagnosed hypertension.

    Science.gov (United States)

    Gryglewska, Barbara; Nęcki, Mirosław; Cwynar, Marcin; Baron, Tomasz; Grodzicki, Tomasz

    2010-12-01

    The aim of the study was to investigate the skin microcirculation blood flow and flowmotion response to heat stress in normotensive subjects with familial predisposition to hypertension and in hypertensive patients. Normotensives without [NT(-)] or with [NT(+)] familial predisposition and subjects with newly diagnosed hypertension (HT) were studied. Clinic blood pressure (BP) measurements and ambulatory BP monitoring as well as laboratory assessments were performed. Resting (RF), heat (HF) and maximal heat (MHF) blood flows were measured using PeriFlux laser Doppler flowmetry (LDF) and expressed as absolute units (AU) and as index of cutaneous vascular conductance (CVC). Spectral analysis of the skin LDF signal was performed by means of the Perisoft dedicated software. Kruskall-Wallis analysis of variance, χ(2) statistic and multivariate reverse regression analysis were used for calculation. The studied population consisted of 70 persons (mean age 36.1 ± 10.3 years, 44.3% women): 17 NT(-), 22 NT(+) and 31 HT, age and gender matched. Higher values of body mass index (BMI), and insulin, glucose and triglyceride levels were observed in HT than in NT groups. RF, HF and MHF were similar in all study groups, but CVC of maximal heat flow differed (p=0.02); in particular, lower values were observed in the HT than in NT(-) group (p=0.01). The study groups differed with regard to total power (p=0.01) and myogenic (p=0.03) origin flowmotion with the lowest values in the NT(+) group. BMI and night BP characteristics were strong predictors of reduction of CVC, MHF and myogenic origin flowmotion. Skin microcirculation response to local heat stress is altered in hypertensive patients with decrease in maximal heat CVC values. Moreover, normotensive subjects with familial predisposition to hypertension are characterized by diminished myogenic origin of skin blood flowmotion.

  9. Subjective health complaints and self-rated health: are expectancies more important than socioeconomic status and workload?

    Science.gov (United States)

    Ree, Eline; Odeen, Magnus; Eriksen, Hege R; Indahl, Aage; Ihlebæk, Camilla; Hetland, Jørn; Harris, Anette

    2014-06-01

    The associations between socioeconomic status (SES), physical and psychosocial workload and health are well documented. According to The Cognitive Activation Theory of Stress (CATS), learned response outcome expectancies (coping, helplessness, and hopelessness) are also important contributors to health. This is in part as independent factors for health, but coping may also function as a buffer against the impact different demands have on health. The purpose of this study was to investigate the relative effect of SES (as measured by level of education), physical workload, and response outcome expectancies on subjective health complaints (SHC) and self-rated health, and if response outcome expectancies mediate the effects of education and physical workload on SHC and self-rated health. A survey was carried out among 1,746 Norwegian municipal employees (mean age 44.2, 81 % females). Structural Equation Models with SHC and self-rated health as outcomes were conducted. Education, physical workload, and response outcome expectancies, were the independent 28 variables in the model. Helplessness/hopelessness had a stronger direct effect on self-rated health and SHC than education and physical workload, for both men and women. Helplessness/hopelessness fully mediated the effect of physical workload on SHC for men (0.121), and mediated 30 % of a total effect of 0.247 for women. For women, education had a small but significant indirect effect through helplessness/hopelessness on self-rated health (0.040) and SHC (-0.040), but no direct effects were found. For men, there was no effect of education on SHC, and only a direct effect on self-rated health (0.134). The results indicated that helplessness/hopelessness is more important for SHC and health than well-established measures on SES such as years of education and perceived physical workload in this sample. Helplessness/hopelessness seems to function as a mechanism between physical workload and health.

  10. A constitutive model for particulate-reinforced titanium matrix composites subjected to high strain rates and high temperatures

    Directory of Open Access Journals (Sweden)

    Song Wei-Dong

    2013-01-01

    Full Text Available Quasi-static and dynamic tension tests were conducted to study the mechanical properties of particulate-reinforced titanium matrix composites at strain rates ranging from 0.0001/s to 1000/s and at temperatures ranging from 20 °C to 650 °C Based on the experimental results, a constitutive model, which considers the effects of strain rate and temperature on hot deformation behavior, was proposed for particulate-reinforced titanium matrix composites subjected to high strain rates and high temperatures by using Zener-Hollomon equations including Arrhenius terms. All the material constants used in the model were identified by fitting Zener-Hollomon equations against the experimental results. By comparison of theoretical predictions presented by the model with experimental results, a good agreement was achieved, which indicates that this constitutive model can give an accurate and precise estimate for high temperature flow stress for the studied titanium matrix composites and can be used for numerical simulations of hot deformation behavior of the composites.

  11. Hormonal changes in the grains of rice subjected to water stress during grain filling.

    Science.gov (United States)

    Yang, J; Zhang, J; Wang, Z; Zhu, Q; Wang, W

    2001-09-01

    Lodging-resistant rice (Oryza sativa) cultivars usually show slow grain filling when nitrogen is applied in large amounts. This study investigated the possibility that a hormonal change may mediate the effect of water deficit that enhances whole plant senescence and speeds up grain filling. Two rice cultivars showing high lodging resistance and slow grain filling were field grown and applied with either normal or high amount nitrogen (HN) at heading. Well-watered and water-stressed (WS) treatments were imposed 9 days post anthesis to maturity. Results showed that WS increased partitioning of fixed (14)CO(2) into grains, accelerated the grain filling rate but shortened the grain filling period, whereas the HN did the opposite way. Cytokinin (zeatin + zeatin riboside) and indole-3-acetic acid contents in the grains transiently increased at early filling stage and WS treatments hastened their declines at the late grain filling stage. Gibberellins (GAs; GA(1) + GA(4)) in the grains were also high at early grain filling but HN enhanced, whereas WS substantially reduced, its accumulation. Opposite to GAs, abscisic acid (ABA) in the grains was low at early grain filling but WS remarkably enhanced its accumulation. The peak values of ABA were significantly correlated with the maximum grain filling rates (r = 0.92**, P water stress during grain filling, especially a decrease in GAs and an increase in ABA, enhances the remobilization of prestored carbon to the grains and accelerates the grain filling rate.

  12. Differences in physical fitness and subjectively rated physical health in Vietnamese and German older adults.

    Science.gov (United States)

    Nguyen, Hung M; Cihlar, Volker

    2013-06-01

    This cross-sectional study aims to investigate the differences in physical fitness and subjectively rated physical health of Vietnamese and German older adults in a community dwelling. The Vietnamese sample was a random sample of 96 community-dwelling individuals aged 60 to 80 years; 50 % were women. Education is 0 % less than 5 years, 23.95 % 5 to 9 years, 47.91 % 10 to 12 years, and 28.12 % more than 12 years. The German sample was a random sample of 159 community-dwelling persons aged 59 to 90 years; 79.8 % were women. Education is 1.25 % less than 5 years, 40.25 % 5 to 9 years, 38.84 % 10 to 12 years, and 21.38 % more than 12 years. Senior Fitness Test and Short Form-36 were used as outcome measures. The Vietnamese sample shows significantly higher performance levels in motor abilities, i.e., aerobic fitness, strength, and flexibility. The Vietnamese sample indicates a lower difference in performance levels between age groups than the German sample. No differences in subjectively rated physical health factors were found. The higher performance levels of the Vietnamese sample might reflect a more active lifestyle throughout the life span, especially in socially mediated domains like living arrangements or labor work. Lower performance levels in the studied age groups of the German sample might lead to higher risks of cardiovascular diseases and proneness of falls. A more active lifestyle after retirement could contribute to a healthier, more capable, and more independent individual and collective aging. Subjectively rated health stated is a culturally mitigated domain and therefore might be independent of actual physical fitness levels.

  13. Effects of caffeine on alcohol reinforcement: Beverage choice, self-administration, and subjective ratings

    Science.gov (United States)

    Sweeney, Mary M.; Meredith, Steven E.; Evatt, Daniel P.; Griffiths, Roland R.

    2017-01-01

    Rationale Combining alcohol and caffeine is associated with increased alcohol consumption, but no prospective experimental studies have examined whether added caffeine increases alcohol consumption. Objectives This study examined how caffeine alters alcohol self-administration and subjective reinforcing effects in healthy adults. Methods Thirty-one participants completed six double-blind alcohol self-administration sessions: three sessions with alcohol only (e.g., Beverage A) and three sessions with alcohol and caffeine (e.g., Beverage B). Participants chose which beverage to consume on a subsequent session (e.g., Beverage A or B). Effects of caffeine on overall beverage choice, number of self-administered drinks, subjective ratings (e.g., Biphasic Alcohol Effects Scale), and psychomotor performance were examined. Results A majority of participants (65%) chose to drink the alcohol beverage containing caffeine on their final self-administration session. Caffeine did not increase the number of self-administered drinks. Caffeine significantly increased stimulant effects, decreased sedative effects, and attenuated decreases in psychomotor performance attributable to alcohol. Relative to nonchoosers, caffeine choosers reported overall lower stimulant ratings, and reported greater drinking behavior prior to the study. Conclusions Although caffeine did not increase the number of self-administered drinks, most participants chose the alcohol beverage containing caffeine. Given the differences in subjective ratings and pre-existing differences in self-reported alcohol consumption for caffeine choosers and nonchoosers, these data suggest decreased stimulant effects of alcohol and heavier self-reported drinking may predict subsequent choice of combined caffeine and alcohol beverages. These predictors may identify individuals who would benefit from efforts to reduce risk behaviors associated with combining alcohol and caffeine. PMID:28108773

  14. Effects of water stress and high temperature on photosynthetic rates of two species of Prosopis.

    Science.gov (United States)

    Delatorre, Jose; Pinto, Manuel; Cardemil, Liliana

    2008-08-21

    The main aim of this research was to compare the photosynthetic responses of two species of Prosopis, Prosopis chilensis (algarrobo) and Prosopis tamarugo (tamarugo) subjected to heat and water stress, to determine how heat shock or water deficit, either individually or combined, affect the photosynthesis of these two species. The photosynthetic rates expressed as a function of photon flow density (PFD) were determined by the O(2) liberated, in seedlings of tamarugo and algarrobo subjected to two water potentials: -0.3 MPa and -2.5 MPa and to three temperatures: 25 degrees C, 35 degrees C and 40 degrees C. Light response curves were constructed to obtain light compensation and light saturation points, maximum photosynthetic rates, quantum yields and dark respiration rates. The photochemical efficiency as the F(v)/F(m) ratio and the amount of RUBISCO were also determined under heat shock, water deficit, and under the combined action of both stress. Photosynthetic rates at a light intensity higher than 500 micromole photons m(-2)s(-1) were not significantly different (P>0.05) between species when measured at 25 degrees C under the same water potential. The maximum photosynthetic rates decreased with temperature in both species and with water deficit in algarrobo. At 40 degrees C and -2.5 MPa, the photosynthetic rate of algarrobo fell to 72% of that of tamarugo. The quantum yield decreased in algarrobo with temperature and water deficit and it was reduced by 50% when the conditions were 40 degrees C and -2.5 MPa. Dark respiration increased by 62% respect to the control at 40 degrees C in tamarugo while remained unchanged in algarrobo. The photochemical efficiency decreased with both, high temperature and water deficit, without differences between species. RUBISCO content increased in algarrobo 35 degrees C. Water deficit reduced the amount of RUBISCO in both species. The results of this work support the conclusion that in both Prosopis species, the interaction between

  15. Relationship between salivary flow rates and Candida counts in subjects with xerostomia.

    Science.gov (United States)

    Torres, Sandra R; Peixoto, Camila Bernardo; Caldas, Daniele Manhães; Silva, Eline Barboza; Akiti, Tiyomi; Nucci, Márcio; de Uzeda, Milton

    2002-02-01

    This study evaluated the relationship between salivary flow and Candida colony counts in the saliva of patients with xerostomia. Sialometry and Candida colony-forming unit (CFU) counts were taken from 112 subjects who reported xerostomia in a questionnaire. Chewing-stimulated whole saliva was collected and streaked in Candida plates and counted in 72 hours. Species identification was accomplished under standard methods. There was a significant inverse relationship between salivary flow and Candida CFU counts (P =.007) when subjects with high colony counts were analyzed (cutoff point of 400 or greater CFU/mL). In addition, the median sialometry of men was significantly greater than that of women (P =.003), even after controlling for confounding variables like underlying disease and medications. Sjögren's syndrome was associated with low salivary flow rate (P =.007). There was no relationship between the median Candida CFU counts and gender or age. There was a high frequency (28%) of mixed colonization. Candida albicans was the most frequent species, followed by C parapsilosis, C tropicalis, and C krusei. In subjects with high Candida CFU counts there was an inverse relationship between salivary flow and Candida CFU counts.

  16. Bilateral hegu acupoints have the same effect on the heart rate variability of the healthy subjects.

    Science.gov (United States)

    Guangjun, Wang; Yuying, Tian; Shuyong, Jia; Wenting, Zhou; Weibo, Zhang

    2014-01-01

    Background. The specificity of acupuncture points (acupoints) is one of the key concepts in traditional acupuncture theory, but the question of whether there is adequate scientific evidence to prove or disprove specificity has been vigorously debated in recent years. Acupoint laterality is an important aspect of acupoint specificity. Data is particularly scarce regarding the laterality of the same channel, namesake acupoint located on opposite sides of the body. Our previous study results suggest that Neiguan acupoint (PC6) has the laterality. The aim of this study was to investigate whether Hegu (LI4) also has laterality from the perspective of heart rate variability. Methods. A total of twenty-eight healthy female volunteers were recruited for this study and were randomly separated into the group I (n = 14) and the group II (n = 14) according to the register order. In the group I, left LI4 was stimulated in the first epoch and the right LI4 was stimulated in the second epoch. In the group II, right LI4 was stimulated in the first epoch and left LI4 was stimulated in the second epoch. Electrocardiogram was recorded and heart rate variability was analyzed. Results. The results show that there were no significant differences of heart rate variablity between the group I and the group II in the time domain and in the frequency domain. Conclusions. Bilateral Hegu acupoints have the same effect on the heart rate variability of the healthy subjects.

  17. Bilateral Hegu Acupoints Have the Same Effect on the Heart Rate Variability of the Healthy Subjects

    Directory of Open Access Journals (Sweden)

    Wang Guangjun

    2014-01-01

    Full Text Available Background. The specificity of acupuncture points (acupoints is one of the key concepts in traditional acupuncture theory, but the question of whether there is adequate scientific evidence to prove or disprove specificity has been vigorously debated in recent years. Acupoint laterality is an important aspect of acupoint specificity. Data is particularly scarce regarding the laterality of the same channel, namesake acupoint located on opposite sides of the body. Our previous study results suggest that Neiguan acupoint (PC6 has the laterality. The aim of this study was to investigate whether Hegu (LI4 also has laterality from the perspective of heart rate variability. Methods. A total of twenty-eight healthy female volunteers were recruited for this study and were randomly separated into the group I (n=14 and the group II (n=14 according to the register order. In the group I, left LI4 was stimulated in the first epoch and the right LI4 was stimulated in the second epoch. In the group II, right LI4 was stimulated in the first epoch and left LI4 was stimulated in the second epoch. Electrocardiogram was recorded and heart rate variability was analyzed. Results. The results show that there were no significant differences of heart rate variablity between the group I and the group II in the time domain and in the frequency domain. Conclusions. Bilateral Hegu acupoints have the same effect on the heart rate variability of the healthy subjects.

  18. Estimation of Circadian Body Temperature Rhythm Based on Heart Rate in Healthy, Ambulatory Subjects.

    Science.gov (United States)

    Sim, Soo Young; Joo, Kwang Min; Kim, Han Byul; Jang, Seungjin; Kim, Beomoh; Hong, Seungbum; Kim, Sungwan; Park, Kwang Suk

    2017-03-01

    Core body temperature is a reliable marker for circadian rhythm. As characteristics of the circadian body temperature rhythm change during diverse health problems, such as sleep disorder and depression, body temperature monitoring is often used in clinical diagnosis and treatment. However, the use of current thermometers in circadian rhythm monitoring is impractical in daily life. As heart rate is a physiological signal relevant to thermoregulation, we investigated the feasibility of heart rate monitoring in estimating circadian body temperature rhythm. Various heart rate parameters and core body temperature were simultaneously acquired in 21 healthy, ambulatory subjects during their routine life. The performance of regression analysis and the extended Kalman filter on daily body temperature and circadian indicator (mesor, amplitude, and acrophase) estimation were evaluated. For daily body temperature estimation, mean R-R interval (RRI), mean heart rate (MHR), or normalized MHR provided a mean root mean square error of approximately 0.40 °C in both techniques. The mesor estimation regression analysis showed better performance than the extended Kalman filter. However, the extended Kalman filter, combined with RRI or MHR, provided better accuracy in terms of amplitude and acrophase estimation. We suggest that this noninvasive and convenient method for estimating the circadian body temperature rhythm could reduce discomfort during body temperature monitoring in daily life. This, in turn, could facilitate more clinical studies based on circadian body temperature rhythm.

  19. Heart rate variability response to mental arithmetic stress in patients with schizophrenia Autonomic response to stress in schizophrenia

    NARCIS (Netherlands)

    Castro, Mariana N.; Vigo, Daniel E.; Weidema, Hylke; Fahrer, Rodolfo D.; Chu, Elvina M.; De Achaval, Delfina; Nogues, Martin; Leiguarda, Ramon C.; Cardinali, Daniel P.; Guinjoan, Salvador N.

    Background: The vulnerability-stress hypothesis is an established model of schizophrenia symptom formation. We sought to characterise the pattern of the cardiac autonomic response to mental arithmetic stress in patients with stable schizophrenia. Methods: We performed heart rate variability (HRV)

  20. Omega-3 fatty acids alter behavioral and oxidative stress parameters in animals subjected to fenproporex administration.

    Science.gov (United States)

    Model, Camila S; Gomes, Lara M; Scaini, Giselli; Ferreira, Gabriela K; Gonçalves, Cinara L; Rezin, Gislaine T; Steckert, Amanda V; Valvassori, Samira S; Varela, Roger B; Quevedo, João; Streck, Emilio L

    2014-03-01

    Studies have consistently reported the participation of oxidative stress in bipolar disorder (BD). Evidences indicate that omega-3 (ω3) fatty acids play several important roles in brain development and functioning. Moreover, preclinical and clinical evidence suggests roles for ω3 fatty acids in BD. Considering these evidences, the present study aimed to investigate the effects of ω3 fatty acids on locomotor behavior and oxidative stress parameters (TBARS and protein carbonyl content) in brain of rats subjected to an animal model of mania induced by fenproporex. The fenproporex treatment increased locomotor behavior in saline-treated rats under reversion and prevention model, and ω3 fatty acids prevented fenproporex-related hyperactivity. Moreover, fenproporex increased protein carbonyls in the prefrontal cortex and cerebral cortex, and the administration of ω3 fatty acids reversed this effect. Lipid peroxidation products also are increased in prefrontal cortex, striatum, hippocampus and cerebral after fenproporex administration, but ω3 fatty acids reversed this damage only in the hippocampus. On the other hand, in the prevention model, fenproporex increased carbonyl content only in the cerebral cortex, and administration of ω3 fatty acids prevented this damage. Additionally, the administration of fenproporex resulted in a marked increased of TBARS in the prefrontal cortex, hippocampus, striatum and cerebral cortex, and prevent this damage in the prefrontal cortex, hippocampus and striatum. In conclusion, we are able to demonstrate that fenproporex-induced hyperlocomotion and damage through oxidative stress were prevented by ω3 fatty acids. Thus, the ω3 fatty acids may be important adjuvant therapy of bipolar disorder.

  1. The Assessing of the Failure Behavior of Glass/Polyester Composites Subject to Quasi Static Stresses

    Science.gov (United States)

    Stanciu, M. D.; Savin, A.; Teodorescu-Drăghicescu, H.

    2017-06-01

    Using glass fabric reinforced composites for structure of wind turbine blades requires high mechanical strengths especially to cyclic stresses. Studies have shown that approximately 50% of composite material failure occurs because of fatigue. Composites behavior to cyclic stresses involves three stages regarding to stiffness variation: the first stage is characterized by the accelerated decline of stiffness with micro-cracks, the second stage - a slight decrease of stiffness characterized by the occurrence of delamination and third stage characterized by higher decreases of resistance and occurrence of fracture thereof. The aim of the paper is to analyzed the behavior of composites reinforced with glass fibers fabric type RT500 and polyester resin subjected to tensile cyclic loading with pulsating quasi-static regime with asymmetry coefficient R = 0. The samples were tested with the universal tensile machine LS100 Lloyd Instruments Plus, with a load capacity of 100 kN. The load was applied with different speeds of 1 mm/min, 10 mm/min and 20 mm/min. After tests, it was observed that the greatest permanent strains were recorded in the first load cycles when the total energy storage by material was lost due to internal friction. With increasing number of cycles, the glass/polyester composites ability to store energy of deformation decreases, the flow phenomenon characterized by large displacements to smaller loading forces appearing.

  2. Foot medial longitudinal-arch deformation during quiet standing and gait in subjects with medial tibial stress syndrome

    DEFF Research Database (Denmark)

    Bandholm, Thomas Quaade; Boysen, Lisbeth; Haugaard, Stine

    2008-01-01

    The objective of this study was to investigate (1) if subjects with medial tibial stress syndrome demonstrate increased navicular drop and medial longitudinal-arch deformation during quiet standing and gait compared with healthy subjects, and (2) the relationship between medial longitudinal-arch ...

  3. Effects of stress on heart rate complexity—A comparison between short-term and chronic stress

    OpenAIRE

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

    2008-01-01

    This study examined chronic and short-term stress effects on heart rate variability (HRV), comparing time, frequency and phase domain (complexity) measures in 50 healthy adults. The hassles frequency subscale of the combined hassles and uplifts scale (CHUS) was used to measure chronic stress. Short-term stressor reactivity was assessed with a speech task. HRV measures were determined via surface electrocardiogram (ECG). Because respiration rate decreased during the speech task (p < .001), thi...

  4. Mindfulness, perceived stress, and subjective well-being: a correlational study in primary care health professionals.

    Science.gov (United States)

    Atanes, Ana C M; Andreoni, Solange; Hirayama, Marcio S; Montero-Marin, Jesús; Barros, Viviam V; Ronzani, Telmo M; Kozasa, Eliza H; Soler, Joaquim; Cebolla, Ausiàs; Garcia-Campayo, Javier; Demarzo, Marcelo M P

    2015-09-02

    Primary health care professionals (PHPs) usually report high levels of distress and burnout symptoms related to job strain. Mindfulness, defined as non-judgmental-present-moment awareness, seems to be a moderator in the causal association between life stressors and well-being. This study aimed to verify correlations among self-reported mindfulness, perceived stress (PS), and subjective well-being (SW) in Brazilian PHPs. We performed a correlational cross-sectional study in a purposive sample of Brazilian PHPs (physicians, nurses, nursing assistants, and community health workers), working in community-oriented primary care programs (known locally as "Family Health Programs"). We used validated self-reporting instruments: the Mindful Attention Awareness Scale (MAAS), the Perceived Stress Scale (PSS), and the Subjective Well-being Scale (SWS). We performed a multivariate analysis of variance (MANOVA), through regression coefficients (beta) in relation to the professional category (nursing assistant), in addition to the length of time in the same job (under than 6 months) that had indicated the lowest level of PS. Participants (n=450) comprised community health workers (65.8%), nursing assistants (18%), registered nurses (10.0%), and doctors (family physicians) (6.0%); 94% were female and 83.1% had worked in the same position for more than one year. MANOVA regression analysis showed differences across professional categories and length of time in the same job position in relation to mindfulness, PS, and SW. Nurses demonstrated lower levels of mindfulness, higher PS, and SW negative affect, as well as lower SW positive affect. Being at work for 1 year or longer showed a clear association with higher PS and lower SW positive affect, and no significance with mindfulness levels. Pearson's coefficient values indicated strong negative correlations between mindfulness and PS, and medium correlations between mindfulness and SW. In this study, there were clear correlations

  5. Stresses in a curved pipe subject to an in-plane bending moment

    International Nuclear Information System (INIS)

    Hofmann, E.; Heeschen, U.

    1979-01-01

    The design of the KWU-primary component supports is mainly defined by the loads of the postulated pipe breaks. To estimate the maximum loading of a component support it is necessary to know the maximum in-plane bending moment (opening and closing) that can be transmitted by a pipe bend. Another reason for such information is that the displacements and distortions of the components cause higher stresses in elbows than in straight pipes. With a detailed knowledge of the deformation characteristic of a pipe bend an integrity analysis could be done without an expensive plastic system analysis. With this purpose in mind experiments were performed with straight pipes and pipe bends of different dimensions subject to in-plane bending moments. The experimental results give the ratio between the maximum transmittable moment of a pipe bend to that of a straight pipe or, the distortion of the end cross-sections and the flattening of the elbow cross-section. An attempt is made to derive simple expressions for estimating the behaviour at pipe elbows. Parallel to the experiments calculations were done for the straight pipe and elbow with a finite difference code with plastic capabilities. The results of the experiment and calculation are compared with the formulas of the ASME-Code section III subjection NB. (orig.)

  6. Response to Dietary Supplementation of Glutamine in Broiler Chickens Subjected to Transportation Stress

    Directory of Open Access Journals (Sweden)

    Majid SHAKERI

    2016-07-01

    Full Text Available The main purpose of this study was to determine effects of glutamine supplementation on performance and blood parameters including Hsp70 and acute phase protein when chicken were subjected to transportation stress. A total of four hundred day-old-male cobb-500 chicks were obtained directly from a local hatchery. The chicks were allotted to two groups as: immediate placement (1 hour after hatching with access to feed and water and placement after 24h transportation without access to feed and water. The experiment consisted of a factorial arrangement of 2 different diets and 2 different time of placement. Chicks from each placement group were fed either basal diet or basal diet + 1% glutamine from 1 to 21 days of age. The results indicated that dietary glutamine improved the body weight gain and feed conversion ratio significantly when chicks were subjected to delayed or immediate placement. In conclusion, supplementing chicken with glutamine in diet can reduce negative effects of delayed access to feed and water during transportation. Moreover, APP concentration and HSP70 level were positively affected when chicks supplemented with glutamine in the diet.

  7. Phenomenological features of dreams: Results from dream log studies using the Subjective Experiences Rating Scale (SERS).

    Science.gov (United States)

    Kahan, Tracey L; Claudatos, Stephanie

    2016-04-01

    Self-ratings of dream experiences were obtained from 144 college women for 788 dreams, using the Subjective Experiences Rating Scale (SERS). Consistent with past studies, dreams were characterized by a greater prevalence of vision, audition, and movement than smell, touch, or taste, by both positive and negative emotion, and by a range of cognitive processes. A Principal Components Analysis of SERS ratings revealed ten subscales: four sensory, three affective, one cognitive, and two structural (events/actions, locations). Correlations (Pearson r) among subscale means showed a stronger relationship among the process-oriented features (sensory, cognitive, affective) than between the process-oriented and content-centered (structural) features--a pattern predicted from past research (e.g., Bulkeley & Kahan, 2008). Notably, cognition and positive emotion were associated with a greater number of other phenomenal features than was negative emotion; these findings are consistent with studies of the qualitative features of waking autobiographical memory (e.g., Fredrickson, 2001). Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Assertive communication in condom negotiation: Insights from late adolescent couples’ subjective ratings of self and partner

    Science.gov (United States)

    Schmid, Amy; Leonard, Noelle R.; Ritchie, Amanda S.; Gwadz, Marya V.

    2015-01-01

    Purpose Assertive communication has been associated with higher levels of condom use among youth using self-report survey methodology. The purpose of this study was to examine the subjective ratings of assertiveness among young, romantically-involved couples in the context of a condom negotiation task. Methods Using an innovative video-recall procedure, 32 couples (64 youth) engaged in a videotaped condom negotiation task and then rated self and partners’ level of assertiveness. Both individual ratings of assertiveness and couple-level assertiveness were assessed using dyadic hierarchical linear modeling. Results Individuals’ assertiveness was positively associated with condom use. Unexpectedly, the overall level of assertiveness in couples showed a curvilinear association with condom use. Very high and very low assertiveness was associated with lower condom use, while moderate levels of assertiveness were associated with higher condom use. Conclusions Moderate levels of assertiveness during condom negotiation may facilitate condom use in young couples. Increasing condom use among romantic partners may require developing interventions that strengthen youths’ ability to engage in assertive communication strategies that balance emotional intimacy with self-advocacy. PMID:25937470

  9. Assertive Communication in Condom Negotiation: Insights From Late Adolescent Couples' Subjective Ratings of Self and Partner.

    Science.gov (United States)

    Schmid, Amy; Leonard, Noelle R; Ritchie, Amanda S; Gwadz, Marya V

    2015-07-01

    Assertive communication has been associated with higher levels of condom use among youth using self-report survey methodology. The purpose of this study was to examine the subjective ratings of assertiveness among young, romantically involved couples in the context of a condom negotiation task. Using an innovative video-recall procedure, 32 couples (64 youth) engaged in a videotaped condom negotiation task and then rated self and partners' level of assertiveness. Both individual ratings of assertiveness and couple-level assertiveness were assessed using dyadic hierarchical linear modeling. Individuals' assertiveness was positively associated with condom use. Unexpectedly, the overall level of assertiveness in couples showed a curvilinear association with condom use. Very high and very low assertiveness was associated with lower condom use, whereas moderate levels of assertiveness were associated with higher condom use. Moderate levels of assertiveness during condom negotiation may facilitate condom use in young couples. Increasing condom use among romantic partners may require developing interventions that strengthen youths' ability to engage in assertive communication strategies that balance emotional intimacy with self-advocacy. Copyright © 2015 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  10. Personality, self-rated health, and subjective age in a life-span sample: the moderating role of chronological age.

    Science.gov (United States)

    Stephan, Yannick; Demulier, Virginie; Terracciano, Antonio

    2012-12-01

    The present study tested whether chronological age moderates the association between subjective age and self-rated health and personality in a community-dwelling life-span sample (N = 1,016; age range: 18-91 years). Self-rated health, extraversion, and openness to experience were associated with a younger subjective age at older ages. Conscientious individuals felt more mature early in life. Conscientiousness, neuroticism, and agreeableness were not related to subjective age at older ages. These findings suggest that with aging self-rated health and personality traits are increasingly important for subjective age. 2013 APA, all rights reserved

  11. Subjectively and objectively measured sleep with and without posttraumatic stress disorder and trauma exposure.

    Science.gov (United States)

    Kobayashi, Ihori; Huntley, Edward; Lavela, Joseph; Mellman, Thomas A

    2012-07-01

    Although reports of sleep disturbances are common among individuals with posttraumatic stress disorder (PTSD), results of polysomnographic (PSG) studies have inconsistently documented abnormalities and have therefore suggested "sleep state misperception." The authors' study objectives were to compare sleep parameters measured objectively and subjectively in the laboratory and at home in civilians with and without trauma exposure and PTSD. Cross-sectional study. PSG recordings in a sleep laboratory and actigraphic recordings in participants' homes. One hundred three urban-residing African Americans with and without trauma exposure and PTSD who participated in a larger study. N/A. Sleep parameters (total sleep time [TST], sleep onset latency [SOL], and wake after sleep onset [WASO]) were assessed using laboratory PSG and home actigraphy. A sleep diary was completed in the morning after PSG and actigraphy recordings. Habitual TST, SOL, and WASO were assessed using a sleep questionnaire. The Clinician Administered PTSD Scale was administered to assess participants' trauma exposure and PTSD diagnostic status. Participants, regardless of their trauma exposure/PTSD status, underestimated WASO in the diary and questionnaire relative to actigraphy and overestimated SOL in the diary relative to PSG. Among participants with current PTSD, TST diary estimates did not differ from the actigraphy measure in contrast with those without current PTSD who overestimated TST. No other significant group differences in discrepancies between subjective and objective sleep measures were found. Discrepancies between subjectively and objectively measured sleep parameters were not associated with trauma exposure or PTSD. This challenges prior assertions that individuals with PTSD overreport their sleep disturbances.

  12. Subjective evaluation of HDTV stereoscopic videos in IPTV scenarios using absolute category rating

    Science.gov (United States)

    Wang, K.; Barkowsky, M.; Cousseau, R.; Brunnström, K.; Olsson, R.; Le Callet, P.; Sjöström, M.

    2011-03-01

    Broadcasting of high definition (HD) stereobased 3D (S3D) TV are planned, or has already begun, in Europe, the US, and Japan. Specific data processing operations such as compression and temporal and spatial resampling are commonly used tools for saving network bandwidth when IPTV is the distribution form, as this results in more efficient recording and transmission of 3DTV signals, however at the same time it inevitably brings quality degradations to the processed video. This paper investigated observers quality judgments of state of the art video coding schemes (simulcast H.264/AVC or H.264/MVC), with or without added temporal and spatial resolution reduction of S3D videos, by subjective experiments using the Absolute Category Rating method (ACR) method. The results showed that a certain spatial resolution reduction working together with high quality video compressing was the most bandwidth efficient way of processing video data when the required video quality is to be judged as "good" quality. As the subjective experiment was performed in two different laboratories in two different countries in parallel, a detailed analysis of the interlab differences was performed.

  13. Sex differences in objective measures of sleep in post-traumatic stress disorder and healthy control subjects.

    Science.gov (United States)

    Richards, Anne; Metzler, Thomas J; Ruoff, Leslie M; Inslicht, Sabra S; Rao, Madhu; Talbot, Lisa S; Neylan, Thomas C

    2013-12-01

    A growing literature shows prominent sex effects for risk for post-traumatic stress disorder and associated medical comorbid burden. Previous research indicates that post-traumatic stress disorder is associated with reduced slow wave sleep, which may have implications for overall health, and abnormalities in rapid eye movement sleep, which have been implicated in specific post-traumatic stress disorder symptoms, but most research has been conducted in male subjects. We therefore sought to compare objective measures of sleep in male and female post-traumatic stress disorder subjects with age- and sex-matched control subjects. We used a cross-sectional, 2 × 2 design (post-traumatic stress disorder/control × female/male) involving83 medically healthy, non-medicated adults aged 19-39 years in the inpatient sleep laboratory. Visual electroencephalographic analysis demonstrated that post-traumatic stress disorder was associated with lower slow wave sleep duration (F(3,82)  = 7.63, P = 0.007) and slow wave sleep percentage (F(3,82)  = 6.11, P = 0.016). There was also a group × sex interaction effect for rapid eye movement sleep duration (F(3,82)  = 4.08, P = 0.047) and rapid eye movement sleep percentage (F(3,82)  = 4.30, P = 0.041), explained by greater rapid eye movement sleep in post-traumatic stress disorder females compared to control females, a difference not seen in male subjects. Quantitative electroencephalography analysis demonstrated that post-traumatic stress disorder was associated with lower energy in the delta spectrum (F(3,82)  = 6.79, P = 0.011) in non-rapid eye movement sleep. Slow wave sleep and delta findings were more pronounced in males. Removal of post-traumatic stress disorder subjects with comorbid major depressive disorder, who had greater post-traumatic stress disorder severity, strengthened delta effects but reduced rapid eye movement effects to non-significance. These findings support previous evidence that post

  14. Rivulet flow round a horizontal cylinder subject to a uniform surface shear stress

    KAUST Repository

    Paterson, C.

    2014-09-14

    © 2014 © The Author, 2014. Published by Oxford University Press; all rights reserved. For Permissions, please email: journals.permissions@oup.com. The steady flow of a slowly varying rivulet with prescribed flux in the azimuthal direction round a large stationary horizontal cylinder subject to a prescribed uniform azimuthal surface shear stress is investigated. In particular, we focus on the case where the volume flux is downwards but the shear stress is upwards, for which there is always a solution corresponding to a rivulet flowing down at least part of one side of the cylinder. We consider both a rivulet with constant non-zero contact angle but slowly varying width (that is, de-pinned contact lines) and a rivulet with constant width but slowly varying contact angle (that is, pinned contact lines), and show that they have qualitatively different behaviour. When shear is present, a rivulet with constant non-zero contact angle can never run all the way from the top to the bottom of the cylinder, and so we consider the scenario in which an infinitely wide two-dimensional film of uniform thickness covers part of the upper half of the cylinder and \\'breaks\\' into a single rivulet with constant non-zero contact angle. In contrast, a sufficiently narrow rivulet with constant width can run all the way from the top to the bottom of the cylinder, whereas a wide rivulet can do so only if its contact lines de-pin, and so we consider the scenario in which the contact lines of a wide rivulet de-pin on the lower half of the cylinder.

  15. Stress hormones predict hyperbolic time-discount rates six months later in adults.

    Science.gov (United States)

    Takahashi, Taiki; Shinada, Mizuho; Inukai, Keigo; Tanida, Shigehito; Takahashi, Chisato; Mifune, Nobuhiro; Takagishi, Haruto; Horita, Yutaka; Hashimoto, Hirofumi; Yokota, Kunihiro; Kameda, Tatsuya; Yamagishi, Toshio

    2010-01-01

    Stress hormones have been associated with temporal discounting. Although time-discount rate is shown to be stable over a long term, no study to date examines whether individual differences in stress hormones could predict individuals' time-discount rates in the relatively distant future (e.g., six month later), which is of interest in neuroeconomics of stress-addiction association. We assessed 87 participants' salivary stress hormone (cortisol, cortisone, and alpha-amylase) levels and hyperbolic discounting of delayed rewards consisting of three magnitudes, at the time-interval of six months. For salivary steroid assays, we employed a liquid chromatography/ mass spectroscopy (LC/MS) method. The correlations between the stress hormone levels and time-discount rates were examined. We observed that salivary alpha-amylase (sAA) levels were negatively associated with time-discount rates in never-smokers. Notably, salivary levels of stress steroids (i.e., cortisol and cortisone) negatively and positively related to time-discount rates in men and women, respectively, in never-smokers. Ever-smokers' discount rates were not predicted from these stress hormone levels. Individual differences in stress hormone levels predict impulsivity in temporal discounting in the future. There are sex differences in the effect of stress steroids on temporal discounting; while there was no sex defference in the relationship between sAA and temporal discounting.

  16. Physiological, biochemical and productive changes in sesame genotypes subjected to different rates of water replenishment

    Directory of Open Access Journals (Sweden)

    Maria S. R. Lima

    Full Text Available ABSTRACT The sesame crop has stood out due to the high nutritional content of its seeds, in addition to being able to be cultivated in the tropical and subtropical regions such as Northeast Brazil. Thus, it is necessary to identify the physiological, biochemical and productive changes related to the tolerance to stress. Objective of this study was to evaluate the physiological, biochemical and productive aspects of sesame genotypes as a function of different rates of water replenishment. The experiment was carried out at the Embrapa Cotton Experimental Unit, located in the municipality of Barbalha-CE, Brazil, under field conditions. The experiment was carried out in a randomized complete block design, with treatments in a factorial scheme (4 × 6, corresponding to four irrigation depths (40, 70, 100 and 130% ETo and six sesame genotypes (G1 = T3-EGSGO3; G2 = T7-EGSGO7; G3 = T5-EGSGO5; G4 = T2-EGSGO2; G5 = T6-EGSGO6; G6 = T4-EGSG04, with three replicates. Data corresponding to the following variables were collected: leaf area, photosynthetic pigments, relative water content in leaf, electrolyte leakage, catalase, peroxidase, yield and oil content. The genotypes did not differ statistically and there were differences in the variables between the water replacement rates. Increments in growth and, consequently, in production, enzymatic activity, oil content and maximum production potential were observed with water depths between 75 and 90% ETo. Contents of chlorophyll a and b, total chlorophyll and carotenoids, were increased with the application of 80% ETo.

  17. Subjective health complaints in older adolescents are related to perceived stress, anxiety and gender – a cross-sectional school study in Northern Sweden

    Directory of Open Access Journals (Sweden)

    Wiklund Maria

    2012-11-01

    Full Text Available Abstract Background Negative trends in adolescent mental and subjective health are a challenge to public health work in Sweden and worldwide. Self-reported mental and subjective health complaints such as pain, sleeping problems, anxiety, and various stress-related problems seem to have increased over time among older adolescents, especially girls. The aim of this study has therefore been to investigate perceived stress, mental and subjective health complaints among older adolescents in Northern Sweden. Methods Data were derived from a cross-sectional school-based survey with a sample consisting of 16–18 year olds (n = 1027, boys and girls, in the first two years of upper secondary school, from different vocational and academic programmes in three public upper secondary schools in a university town in northern Sweden. Prevalence of perceived stress, subjective health complaints, general self-rated health, anxiety, and depression were measured using a questionnaire, including the Hospital Anxiety and Depression Scale (HADS. Results A large proportion of both girls and boys reported health complaints and perceived stress. There was a clear gender difference: two to three times as many girls as boys reported subjective health complaints, such as headache, tiredness and sleeping difficulties and musculoskeletal pain, as well as sadness and anxiety. High pressure and demands from school were experienced by 63.6% of girls and 38.5% of boys. Perceived stress in the form of pressure and demands correlated strongly with reported health complaints (r = 0.71 and anxiety (r = 0.71. Conclusions The results indicate that mental and subjective health complaints are prevalent during adolescence, especially in girls, and furthermore, that perceived stress and demands may be important explanatory factors. Future studies should pay attention to the balance between gender-related demands, perceived control and social support, particularly in the

  18. Comparative Evaluation of Common Savannahgrass on a Range of Soils Subjected to Different Stresses I: Productivity and Quality

    Directory of Open Access Journals (Sweden)

    Raymond Springer

    2014-04-01

    Full Text Available Turfgrass growth, performance and quality are affected by abiotic stress factors and are of primary concern for persons managing turfgrass areas under seasonal tropical climates. Under these conditions, common Savannahgrass (SG may have a performance advantage over imported hybrid turfgrasses. A greenhouse study was conducted to comparatively evaluate the performance of tropical turfgrasses exposed to water and compaction related stresses across a range of soils, with or without the addition of a surface sand layer. Turfgrass productivity and quality was monitored over a four-month growth period. Clipping yield (CY was lower at the higher compaction effort for all turfgrasses, but across all stresses, drought (D and waterlogging (WL resulted in lower CY. Values were significantly lower under D. SG had the highest clipping yield across all soils. The chlorophyll index (CI was lower for all turfgrasses under water-induced stress compared to compaction stresses. SG had a significantly higher CI across all stress treatments. Correlation analysis showed a positive (r² = 0.420 and significant (p < 0.05 relationship between CY and CI. Similar to CI, stress type influenced turfgrass visual quality (VQ, with D stress, resulting in the lowest VQ rating among turfgrasses. Bermudagrass (BG had the lowest VQ across all stress treatments, whilst, comparatively, Zoysiagrass (ZG had significantly higher VQ under high compaction (HC, low compaction (LC and WL stress. Overall, SG showed a higher level of tolerance to applied stresses and warrants greater attention as a potential turfgrass under tropical conditions.

  19. Intervarietal variations in various oxidative stress markers and antioxidant potential of finger millet (Eleusine coracana) subjected to drought stress.

    Science.gov (United States)

    Bartwal, Arti; Pande, Anjali; Sharma, Priyadarshini; Arora, Sandeep

    2016-07-01

    Drought is a major form of abiotic stress leading to lower crop productivity. Experiment was carried out for selecting the most tolerant genotype among six different genotypes of finger millet under drought stress. Seeds of six finger millet genotypes were sown in pots and grown for 35 days. After this period, drought was induced by withholding watering for stressed plants while control plants were watered regularly for comparison. Among all six different varieties of finger millet screened (PR202, PES400, PRM6107, VL283, VL328 and VL149) under varying intensities of drought stress,PRM6107 and PR202 showed highest stress tolerance by limiting excessive accumulation of reactive oxygen species (ROS) through activation of ROS scavenging antioxidative enzymes. A 200% increase in ascorbate content was recorded in PRM6107 and PR202, while in other varieties limited increase in ascorbate content was observed. Maximum decrease in chlorophyll content was observed in VL328 (83%) while least drop was observed in VL149 (65%). Relative water content indicated that PR202 was able to retain maximum water content under stress, as it recorded least drop in relative water content (55%), contributing to its better survival under stress. In conclusion finger millet genotypes PRM6107 and PR202 possessed maximum drought tolerance potential and thus may be used for allele mining of drought tolerant genes, which can further be employed for the development of more drought stress tolerant staple crops using biotechnological approach.

  20. Dose titration of BAF312 attenuates the initial heart rate reducing effect in healthy subjects.

    Science.gov (United States)

    Legangneux, Eric; Gardin, Anne; Johns, Donald

    2013-03-01

    Previous studies have shown transient decreases in heart rate (HR) following administration of sphingosine 1-phosphate (S1P) receptor modulators including BAF312. This study was conducted to determine whether dose titration of BAF312 reduces or eliminates these effects. Fifty-six healthy subjects were randomized 1:1:1:1 to receive BAF312 in one of two dose titration (DT) regimens (DT1 and DT2: 0.25-10 mg over 9-10 days), no titration (10 mg starting dose) or placebo. Pharmacodynamic and pharmacokinetic parameters were assessed. Neither DT1 nor DT2 resulted in clinically significant bradycardia or atrioventricular conduction effects. Both titration regimens showed a favourable difference on each of days 1-12 vs. the non-titration regimen on day 1 for HR effects (P titration was 1.18 (95% confidence interval [CI] 1.13, 1.23) and 1.14 (95% CI 1.09, 1.18) for DT2 (both P titration HRs showed considerable separation from placebo throughout the study. There was no statistically significant reduction in HR vs. placebo on day 1 in either titration regimen. On days 3-7 subjects in DT1 and DT2 experienced minor reductions in HR vs. placebo (approximately 5 beats min⁻¹; P ≤ 0.0001). From days 9-12, HRs in both titration regimens were comparable with placebo. Both titration regimens effectively attenuated the initial bradyarrhythmia observed on day 1 of treatment with BAF312 10 mg. © 2012 Novartis Institutes for BioMedical Research (NIBIR). British Journal of Clinical Pharmacology © 2012 The British Pharmacological Society.

  1. Acid-base balance in rainbow trout (Salmo gairdneri) subjected to acid stresses

    Energy Technology Data Exchange (ETDEWEB)

    Eddy, F.B.

    1976-01-01

    The respiratory properties of rainbow-trout blood were investigated in acid-stressed fish. In the first group acid was introduced into the bloodstream and in the second the carbon dioxide content of the ambient water was increased. Initially the introduction of the acid to the blood caused a decrease in blood pH and bicarbonate, and increases in oxygen uptake and ventilation volume. After 2 to 3 h these values had returned to the control levels. Trout subjected to high ambient CO/sub 2/ (about 10 mmHg) showed a decrease in blood pH while PCO/sub 2/ and bicarbonate increased. After 8 h the trout began to show signs of compensation to the acidosis. In each experiment the blood PO/sub 2/ was little changed but blood O/sub 2/ content was decreased and tended not to resume the control value even after several hours. The results are discussed in terms of the various acid-base mechanisms thought to be available to the fish. These include branchial ion exchanges and the possible buffering roles of the extracellular and intracellular fluids.

  2. Symptoms and subjective quality of life in post-traumatic stress disorder: a longitudinal study.

    Science.gov (United States)

    Giacco, Domenico; Matanov, Aleksandra; Priebe, Stefan

    2013-01-01

    Evidence suggests that post-traumatic stress disorder (PTSD) is associated with substantially reduced subjective quality of life (SQOL). This study aimed to explore whether and how changes in the levels of PTSD symptom clusters of intrusion, avoidance and hyperarousal are associated with changes in SQOL. Two samples with PTSD following the war in former Yugoslavia were studied, i.e. a representative sample of 530 people in five Balkan countries and a non-representative sample of 215 refugees in three Western European countries. They were assessed on average eight years after the war and re-interviewed one year later. PTSD symptoms were assessed on the Impact of Event Scale - Revised and SQOL on the Manchester Short Assessment of Quality of Life. Linear regression and a two-wave cross lagged panel analysis were used to explore the association between PTSD symptom clusters and SQOL. The findings in the two samples were consistent. Symptom reduction over time was associated with improved SQOL. In multivariable analyses adjusted for the influence of all three clusters, gender and time since war exposure, only changes in hyperarousal symptoms were significantly associated with changes in SQOL. The two-wave cross-lagged panel analysis suggested that the link between hyperarousal symptoms and SQOL is bidirectional. Low SQOL of patients with war-related PTSD is particularly associated with hyperarousal symptoms. The findings suggest a bidirectional influence: a reduction in hyperarousal symptoms may result in improved SQOL, and improvements in SQOL may lead to reduced hyperarousal symptoms.

  3. Seed viability of Dimorphandra gardneriana subject to water stress in different temperatures

    Directory of Open Access Journals (Sweden)

    Marina Matias Ursulino

    Full Text Available ABSTRACT: The forest species Dimorphandra gardneriana Tul. is widely used for various pharmacological products, yet few basic studies have been undertaken to understand their ecological and physiological attributes under stress conditions. The goal of this research was to evaluate the seed germination and vigor when subjected to different osmotic potentials and temperatures. Water restriction was simulated with polyethylene glycol 6000 solution (PEG 6000 with osmotic potentials of 0; -0,2; -0,4; -0,6; -0,8, and -1,0MPa at temperatures of 20, 25, 30, and 35°C. The effect of the treatment was determined by the germination and vigor (germination speed index, length and phytomass of dry shoot and roots of the seeds, in an entirely random design with four repetitions. From-0, 4MPa it occurs a drastic reduction in germination and vigor of seeds although these factors were less affected at temperature of 25°C up to -0, 2MPa.

  4. The Synchronous Generators Rated Speed’s Influence on Electromagnetic Stresses and on Costs

    Directory of Open Access Journals (Sweden)

    Elisabeta Spunei

    2013-09-01

    Full Text Available During the design of synchronous generators is very important to establish the values of their electromagnetic stresses. The specific literature recommends that these stress values are to be chosen from the curves obtained during experimental design, where the independent values are the polar pitch and the number of pole pairs. The authors of this work propose a method of finding the dependency between the electromagnetic stress and the synchronous generator rated speed to rapidly estimate the stresses in a given interval of rated speed values.

  5. Examining coping style and the relationship between stress and subjective well-being in Australia's 'sandwich generation'.

    Science.gov (United States)

    Gillett, Jade E; Crisp, Dimity A

    2017-09-01

    The sandwich generation represents adults, often in midlife, who care for both children and ageing parents/relatives. While the stress they experience has received some attention, little research has investigated the subjective well-being (SWB) of this population. This study examined the relationship between perceived stress and SWB and the moderating effect of coping style. Ninety-three participants (80 women), aged 23-63 years, completed an online survey measuring perceived stress, coping strategies, life satisfaction and positive and negative affect. Stress was negatively associated with SWB. While emotion- and problem-focused coping were directly associated with SWB outcomes, the only moderating effect found was for avoidance-focused coping (AFC). Specifically, AFC was associated with higher positive affect for those reporting lower stress. This study highlights the need to recognise the distinct circumstances that exist for the sandwich generation. Limitations and suggestions for future research are discussed. © 2017 AJA Inc.

  6. Transcriptome analysis and identification of significantly differentially expressed genes in Holstein calves subjected to severe thermal stress

    Science.gov (United States)

    Srikanth, Krishnamoorthy; Lee, Eunjin; Kwan, Anam; Lim, Youngjo; Lee, Junyep; Jang, Gulwon; Chung, Hoyoung

    2017-11-01

    RNA-Seq analysis was used to characterize transcriptome response of Holstein calves to thermal stress. A total of eight animals aged between 2 and 3 months were randomly selected and subjected to thermal stress corresponding to a temperature humidity index of 95 in an environmentally controlled house for 12 h consecutively for 3 days. A set of 15,787 unigenes were found to be expressed and after a threshold of threefold change, and a Q value physiological and metabolic processes to survive. Many of the genes identified in this study have not been previously reported to be involved in thermal stress response. The results of this study extend our understanding of the animal's response to thermal stress and some of the identified genes may prove useful in the efforts to breed Holstein cattle with superior thermotolerance, which might help in minimizing production loss due to thermal stress.

  7. Comparative proteome analysis of metabolic proteins from seeds of durum wheat (cv. Svevo) subjected to heat stress

    DEFF Research Database (Denmark)

    Laino, Paolo; Shelton, Dale; Finnie, Christine

    2010-01-01

    of nonprolamin proteins were monitored to identify polypeptides affected by heat stress during grain fill. This study shows that heat stress alters significantly the durum wheat seed proteome, although the changes range is only between 1.2- and 2.2-fold. This analysis revealed 132 differentially expressed...... include proteins with metabolic activity or structural function. In order to investigate the consequences of heat stress on the accumulation of nonprolamin proteins in mature durum wheat kernels, the Italian cultivar Svevo was subjected to two thermal regimes (heat stress versus control). The 2-D patterns...... polypeptides, 47 of which were identified by MALDI-TOF and MALDI-TOF-TOF MS and included HSPs, proteins involved in the glycolysis and carbohydrate metabolism, as well as stress-related proteins. Many of the heat-induced polypeptides are considered to be allergenic for sensitive individuals....

  8. Customized rating assessment of climate suitability (CRACS): climate satisfaction evaluation based on subjective perception

    Science.gov (United States)

    Lin, Tzu-Ping; Yang, Shing-Ru; Matzarakis, Andreas

    2015-12-01

    Climate not only influences the behavior of people in urban environments but also affects people's schedules and travel plans. Therefore, providing people with appropriate long-term climate evaluation information is crucial. Therefore, we developed an innovative climate assessment system based on field investigations conducted in three cities located in Northern, Central, and Southern Taiwan. The field investigations included the questionnaire surveys and climate data collection. We first analyzed the relationship between the participants and climate parameters comprising physiologically equivalent temperature, air temperature, humidity, wind speed, solar radiation, cloud cover, and precipitation. Second, we established the neutral value, comfort range, and dissatisfied range of each parameter. Third, after verifying that the subjects' perception toward the climate parameters vary based on individual preferences, we developed the customized rating assessment of climate suitability (CRACS) approach, which featured functions such as personalized and default climate suitability information to be used by users exhibiting varying demands. Finally, we performed calculations using the climate conditions of two cities during the past 10 years to demonstrate the performance of the CRACS approach. The results can be used as a reference when planning activities in the city or when organizing future travel plans. The flexibility of the assessment system enables it to be adjusted for varying regions and usage characteristics.

  9. Effect of non-alcoholic beer on Subjective Sleep Quality in a university stressed population.

    Science.gov (United States)

    Franco, L; Bravo, R; Galán, C; Rodríguez, A B; Barriga, C; Cubero, Javier

    2014-09-01

    Sleep deprivation affects the homeostasis of the physiological functions in the human organism. Beer is the only beverage that contains hops, a plant which has a sedative effect. Our objective is to determine the improvement of subjective sleep quality using the Pittsburgh Sleep Quality Index (PSQI). The sample was conducted among a population of 30 university students. The study took place during a period of 3 weeks, the first 7 days were used for the Control, and during the following 14 days the students ingested beer (were asked to drink non-alcoholic beer) while having dinner. The results revealed that Subjective Sleep Quality improved in the case of those students who drank one beer during dinner compared to the Control, this is corroborated by the fact that Sleep Latency decreased (p < 0.05) compared to their Control. The overall rating Global Score of Quality of Sleep also improved significantly (p < 0.05). These results confirm that the consumption of non-alcoholic beer at dinner time helps to improve the quality of sleep at night.

  10. Effects of Yoga on Stress, Stress Adaption, and Heart Rate Variability Among Mental Health Professionals--A Randomized Controlled Trial.

    Science.gov (United States)

    Lin, Shu-Ling; Huang, Ching-Ya; Shiu, Shau-Ping; Yeh, Shu-Hui

    2015-08-01

    Mental health professionals experiencing work-related stress may experience burn out, leading to a negative impact on their organization and patients. The aim of this study was to examine the effects of yoga classes on work-related stress, stress adaptation, and autonomic nerve activity among mental health professionals. A randomized controlled trial was used, which compared the outcomes between the experimental (e.g., yoga program) and the control groups (e.g., no yoga exercise) for 12 weeks. Work-related stress and stress adaptation were assessed before and after the program. Heart rate variability (HRV) was measured at baseline, midpoint through the weekly yoga classes (6 weeks), and postintervention (after 12 weeks of yoga classes). The results showed that the mental health professionals in the yoga group experienced a significant reduction in work-related stress (t = -6.225, p control group revealed no significant changes. Comparing the mean differences in pre- and posttest scores between yoga and control groups, we found the yoga group significantly decreased work-related stress (t = -3.216, p = .002), but there was no significant change in stress adaptation (p = .084). While controlling for the pretest scores of work-related stress, participants in yoga, but not the control group, revealed a significant increase in autonomic nerve activity at midpoint (6 weeks) test (t = -2.799, p = .007), and at posttest (12 weeks; t = -2.099, p = .040). Because mental health professionals experienced a reduction in work-related stress and an increase in autonomic nerve activity in a weekly yoga program for 12 weeks, clinicians, administrators, and educators should offer yoga classes as a strategy to help health professionals reduce their work-related stress and balance autonomic nerve activities. © 2015 The Authors. Worldviews on Evidence-Based Nursing published by Wiley Periodicals, Inc. on behalf of Society for Worldviews on Evidence-Based Nursing.

  11. Shear-Rate-Dependent Behavior of Clayey Bimaterial Interfaces at Landslide Stress Levels

    Science.gov (United States)

    Scaringi, Gianvito; Hu, Wei; Xu, Qiang; Huang, Runqiu

    2018-01-01

    The behavior of reactivated and first-failure landslides after large displacements is controlled by the available shear resistance in a shear zone and/or along slip surfaces, such as a soil-bedrock interface. Among the factors influencing the resistance parameter, the dependence on the shear rate can trigger catastrophic evolution (rate-weakening) or exert a slow-down feedback (rate-strengthening) upon stress perturbation. We present ring-shear test results, performed under various normal stresses and shear rates, on clayey soils from a landslide shear zone, on its parent lithology and other lithologies, and on clay-rock interface samples. We find that depending on the materials in contact, the normal stress, and the stress history, the shear-rate-dependent behaviors differ. We discuss possible models and underlying mechanisms for the time-dependent behavior of landslides in clay soils.

  12. The Potential Explanatory Role of Perceived Stress in Associations Between Subjective Social Status and Health-Related Quality of Life Among Homeless Smokers.

    Science.gov (United States)

    Garey, Lorra; Reitzel, Lorraine R; Kendzor, Darla E; Businelle, Michael S

    2016-01-01

    Homeless individuals smoke at high rates relative to the general population and are at heightened risk of tobacco-related illnesses and poor health-related quality of life (HRQoL). Homeless smokers also report low subjective social status (SSS) or perceived social standing relative to others. SSS may contribute to poor HRQoL, potentially through perceived stress. The current study examined the role of perceived stress in the association of SSS and HRQoL among 227 (70.9% male, Mage = 43.2) homeless smokers. Participants completed self-report measures of SSS, perceived stress, and HRQoL. Perceived stress partially explained the relation between SSS (United States and Community) and HRQoL in covariate-adjusted analyses. Results suggested that perceived stress is a pathway through which SSS contributes to HRQoL among homeless smokers. Findings broaden current understanding of the impact of social disadvantage and perceived stress on HRQoL among homeless smokers. © The Author(s) 2015.

  13. Spall damage of a mild carbon steel: Effects of peak stress, strain rate and pulse duration

    International Nuclear Information System (INIS)

    Li, C.; Li, B.; Huang, J.Y.; Ma, H.H.; Zhu, M.H.; Zhu, J.; Luo, S.N.

    2016-01-01

    We investigate spall damage of a mild carbon steel under high strain-rate loading, regarding the effects of peak stress, strain rate, and pulse duration on spall strength and damage, as well as related microstructure features, using gas gun plate impact, laser velocimetry, and electron backscatter diffraction analysis. Our experiments demonstrate strong dependences of spall strength on peak stress and strain rate, and its weak dependence on pulse duration. We establish numerical relations between damage and peak stress or pulse duration. Brittle and ductile spall fracture modes are observed at different loading conditions. Damage nucleates at grain boundaries and triple junctions, either as transgranular cleavage cracks or voids.

  14. Death and population dynamics affect mutation rate estimates and evolvability under stress in bacteria.

    Science.gov (United States)

    Frenoy, Antoine; Bonhoeffer, Sebastian

    2018-05-01

    The stress-induced mutagenesis hypothesis postulates that in response to stress, bacteria increase their genome-wide mutation rate, in turn increasing the chances that a descendant is able to better withstand the stress. This has implications for antibiotic treatment: exposure to subinhibitory doses of antibiotics has been reported to increase bacterial mutation rates and thus probably the rate at which resistance mutations appear and lead to treatment failure. More generally, the hypothesis posits that stress increases evolvability (the ability of a population to generate adaptive genetic diversity) and thus accelerates evolution. Measuring mutation rates under stress, however, is problematic, because existing methods assume there is no death. Yet subinhibitory stress levels may induce a substantial death rate. Death events need to be compensated by extra replication to reach a given population size, thus providing more opportunities to acquire mutations. We show that ignoring death leads to a systematic overestimation of mutation rates under stress. We developed a system based on plasmid segregation that allows us to measure death and division rates simultaneously in bacterial populations. Using this system, we found that a substantial death rate occurs at the tested subinhibitory concentrations previously reported to increase mutation rate. Taking this death rate into account lowers and sometimes removes the signal for stress-induced mutagenesis. Moreover, even when antibiotics increase mutation rate, we show that subinhibitory treatments do not increase genetic diversity and evolvability, again because of effects of the antibiotics on population dynamics. We conclude that antibiotic-induced mutagenesis is overestimated because of death and that understanding evolvability under stress requires accounting for the effects of stress on population dynamics as much as on mutation rate. Our goal here is dual: we show that population dynamics and, in particular, the

  15. Spall damage of a mild carbon steel: Effects of peak stress, strain rate and pulse duration

    Energy Technology Data Exchange (ETDEWEB)

    Li, C. [College of Physical Science and Technology, Sichuan University, Chengdu, Sichuan 610064 (China); Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); The Peac Institute of Multiscale Sciences, Chengdu, Sichuan 610031 (China); Li, B.; Huang, J.Y. [The Peac Institute of Multiscale Sciences, Chengdu, Sichuan 610031 (China); CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui 230027 (China); Ma, H.H. [CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui 230027 (China); Zhu, M.H. [Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhu, J., E-mail: zhujun01@163.com [College of Physical Science and Technology, Sichuan University, Chengdu, Sichuan 610064 (China); Luo, S.N., E-mail: sluo@pims.ac.cn [The Peac Institute of Multiscale Sciences, Chengdu, Sichuan 610031 (China); Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China)

    2016-04-13

    We investigate spall damage of a mild carbon steel under high strain-rate loading, regarding the effects of peak stress, strain rate, and pulse duration on spall strength and damage, as well as related microstructure features, using gas gun plate impact, laser velocimetry, and electron backscatter diffraction analysis. Our experiments demonstrate strong dependences of spall strength on peak stress and strain rate, and its weak dependence on pulse duration. We establish numerical relations between damage and peak stress or pulse duration. Brittle and ductile spall fracture modes are observed at different loading conditions. Damage nucleates at grain boundaries and triple junctions, either as transgranular cleavage cracks or voids.

  16. Dynamics of heart rate variability analysed through nonlinear and linear dynamics is already impaired in young type 1 diabetic subjects.

    Science.gov (United States)

    Souza, Naiara M; Giacon, Thais R; Pacagnelli, Francis L; Barbosa, Marianne P C R; Valenti, Vitor E; Vanderlei, Luiz C M

    2016-10-01

    Autonomic diabetic neuropathy is one of the most common complications of type 1 diabetes mellitus, and studies using heart rate variability to investigate these individuals have shown inconclusive results regarding autonomic nervous system activation. Aims To investigate the dynamics of heart rate in young subjects with type 1 diabetes mellitus through nonlinear and linear methods of heart rate variability. We evaluated 20 subjects with type 1 diabetes mellitus and 23 healthy control subjects. We obtained the following nonlinear indices from the recurrence plot: recurrence rate (REC), determinism (DET), and Shanon entropy (ES), and we analysed indices in the frequency (LF and HF in ms2 and normalised units - nu - and LF/HF ratio) and time domains (SDNN and RMSSD), through analysis of 1000 R-R intervals, captured by a heart rate monitor. There were reduced values (p<0.05) for individuals with type 1 diabetes mellitus compared with healthy subjects in the following indices: DET, REC, ES, RMSSD, SDNN, LF (ms2), and HF (ms2). In relation to the recurrence plot, subjects with type 1 diabetes mellitus demonstrated lower recurrence and greater variation in their plot, inter-group and intra-group, respectively. Young subjects with type 1 diabetes mellitus have autonomic nervous system behaviour that tends to randomness compared with healthy young subjects. Moreover, this behaviour is related to reduced sympathetic and parasympathetic activity of the autonomic nervous system.

  17. Ventilation rates indicate stress-coping styles in Nile tilapia

    Indian Academy of Sciences (India)

    increase and act in an active (e.g. high-level aggression or avoidance) manner in ... hand, VR can be linked to metabolic rates (Alvarenga and. Volpato 1995). ... dry pellets (22% protein, Purina® Ltd, Campinas, SP, Brazil). Leftover food was ... food offered, but this technique guaranteed fish were able to eat until satiation.

  18. Stress Introduction Rate Alters the Benefit of AcrAB-TolC Efflux Pumps.

    Science.gov (United States)

    Langevin, Ariel M; Dunlop, Mary J

    2018-01-01

    Stress tolerance studies are typically conducted in an all-or-none fashion. However, in realistic settings-such as in clinical or metabolic engineering applications-cells may encounter stresses at different rates. Therefore, how cells tolerate stress may depend on its rate of appearance. To address this, we studied how the rate of stress introduction affects bacterial stress tolerance by focusing on a key stress response mechanism. Efflux pumps, such as AcrAB-TolC of Escherichia coli , are membrane transporters well known for the ability to export a wide variety of substrates, including antibiotics, signaling molecules, and biofuels. Although efflux pumps improve stress tolerance, pump overexpression can result in a substantial fitness cost to the cells. We hypothesized that the ideal pump expression level would involve a rate-dependent trade-off between the benefit of pumps and the cost of their expression. To test this, we evaluated the benefit of the AcrAB-TolC pump under different rates of stress introduction, including a step, a fast ramp, and a gradual ramp. Using two chemically diverse stresses, the antibiotic chloramphenicol and the jet biofuel precursor pinene, we assessed the benefit provided by the pumps. A mathematical model describing these effects predicted the benefit as a function of the rate of stress introduction. Our findings demonstrate that as the rate of introduction is lowered, stress response mechanisms provide a disproportionate benefit to pump-containing strains, allowing cells to survive beyond the original inhibitory concentrations. IMPORTANCE Efflux pumps are ubiquitous in nature and provide stress tolerance in the cells of species ranging from bacteria to mammals. Understanding how pumps provide tolerance has far-reaching implications for diverse fields, from medicine to biotechnology. Here, we investigated how the rate of stressor appearance impacts tolerance. We focused on two distinct substrates of AcrAB-TolC efflux pumps, the

  19. Growth and microtubule orientation of Zea mays roots subjected to osmotic stress

    Science.gov (United States)

    Blancaflor, E. B.; Hasenstein, K. H.

    1995-01-01

    Previous work has shown that microtubule (MT) reorientation follows the onset of growth inhibition on the lower side of graviresponding roots, indicating that growth reduction can occur independently of MT reorientation. To test this observation further, we examined whether the reduction in growth in response to osmotic stress is correlated with MT reorientation. The distribution and rate of growth in maize roots exposed to 350 mOsm sorbitol and KCl or 5 mM Mes/Tris buffer were measured with a digitizer. After various times roots were processed for indirect immunofluorescence microscopy. Application of sorbitol or KCl had no effect on the organization of MTs in the apical 2 mm of the root but resulted in striking and different effects in the basal region of the root. Sorbitol treatment caused rapid appearance of oval to circular holes in the microtubular array that persisted for at least 9 h. Between 30 min and 4 h of submersion in KCl, MTs in cortical cells 4 mm and farther from the quiescent center began to reorient oblique to the longitudinal axis. After 9 h, the alignment of MTs had shifted to parallel to the root axis but MTs of the epidermal cells remained transverse. In KCl-treated roots MT reorientation appeared to follow a pattern of development similar to that in controls but without elongation. Our data provide additional evidence that MT reorientation is not the cause but a consequence of growth inhibition.

  20. Symptoms and subjective quality of life in post-traumatic stress disorder: a longitudinal study.

    Directory of Open Access Journals (Sweden)

    Domenico Giacco

    Full Text Available BACKGROUND: Evidence suggests that post-traumatic stress disorder (PTSD is associated with substantially reduced subjective quality of life (SQOL. This study aimed to explore whether and how changes in the levels of PTSD symptom clusters of intrusion, avoidance and hyperarousal are associated with changes in SQOL. METHODS: Two samples with PTSD following the war in former Yugoslavia were studied, i.e. a representative sample of 530 people in five Balkan countries and a non-representative sample of 215 refugees in three Western European countries. They were assessed on average eight years after the war and re-interviewed one year later. PTSD symptoms were assessed on the Impact of Event Scale - Revised and SQOL on the Manchester Short Assessment of Quality of Life. Linear regression and a two-wave cross lagged panel analysis were used to explore the association between PTSD symptom clusters and SQOL. RESULTS: The findings in the two samples were consistent. Symptom reduction over time was associated with improved SQOL. In multivariable analyses adjusted for the influence of all three clusters, gender and time since war exposure, only changes in hyperarousal symptoms were significantly associated with changes in SQOL. The two-wave cross-lagged panel analysis suggested that the link between hyperarousal symptoms and SQOL is bidirectional. CONCLUSIONS: Low SQOL of patients with war-related PTSD is particularly associated with hyperarousal symptoms. The findings suggest a bidirectional influence: a reduction in hyperarousal symptoms may result in improved SQOL, and improvements in SQOL may lead to reduced hyperarousal symptoms.

  1. Differentiation of pain ratings in combat-related posttraumatic stress disorder.

    Science.gov (United States)

    Kraus, Anja; Geuze, Elbert; Schmahl, Christian; Greffrath, Wolfgang; Treede, Rolf-Detlef; Bohus, Martin; Vermetten, Eric

    2009-06-01

    Although posttraumatic stress disorder (PTSD) is associated with chronic pain, preliminary evidence suggests reduced experimental pain sensitivity in this disorder. The questions addressed in the present study were whether pain perception would also be reduced in PTSD patients who are not suffering from chronic pain symptoms, and whether a reduction in pain sensitivity would also be present in combat veterans who did not develop PTSD. For this, we determined thermal detection and pain thresholds in 10 male combat-related PTSD patients, 10 combat control subjects (no PTSD) and 10 healthy controls without combat experience. All subjects were pain free. First, we measured thermal sensory thresholds with ramped heat and cold stimuli using the method of limits. Ramped thermal sensory stimulation revealed no deficits for the detection of (non-noxious) f2.1thermal stimuli between groups. In contrast, heat and cold pain thresholds in both combat groups (PTSD and combat controls) were significantly increased compared to healthy controls. However, these stimuli could not distinguish between the two groups due to ceiling effects. When using longer-lasting heat stimulation at different temperatures (30s duration; method of fixed stimuli), we found significantly lower frequency of pain reports in PTSD patients compared with both combat and healthy controls, as well as significantly lower pain ratings. Our results suggest an association of PTSD with reduced pain sensitivity, which could be related to PTSD-related (neuro-)psychological alterations or to a pre-existing risk factor for the disorder.

  2. 49 CFR Appendix B to Part 541 - Light Duty Truck Lines With Theft Rates Below the 1990/91 Median Theft Rate, Subject to the...

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Light Duty Truck Lines With Theft Rates Below the 1990/91 Median Theft Rate, Subject to the Requirements of This Standard B Appendix B to Part 541... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION FEDERAL MOTOR VEHICLE THEFT PREVENTION STANDARD Pt. 541, App. B...

  3. Cortical surface area reduction in identification of subjects at high risk for post-traumatic stress disorder: A pilot study.

    Science.gov (United States)

    Hu, Hao; Sun, Yawen; Su, Shanshan; Wang, Yao; Qiu, Yongming; Yang, Xi; Zhou, Yan; Xiao, Zeping; Wang, Zhen

    2018-01-01

    Victims of motor vehicle accidents often develop post-traumatic stress disorder, which causes significant social function loss. For the difficulty in treating post-traumatic stress disorder, identification of subjects at high risk for post-traumatic stress disorder is essential for providing possible intervention. This paper aims to examine the cortical structural traits related to susceptibility to post-traumatic stress disorder. To address this issue, we performed structural magnetic resonance imaging study in motor vehicle accident victims within 48 hours from the accidents. A total of 70 victims, available for both clinical and magnetic resonance imaging data, enrolled in our study. Upon completion of 6-month follow-up, 29 of them developed post-traumatic stress disorder, while 41 of them didn't. At baseline, voxelwise comparisons of cortical thickness, cortical area and cortical volume were conducted between post-traumatic stress disorder group and trauma control group. As expected, several reduced cortical volume within frontal-temporal loop were observed in post-traumatic stress disorder. For cortical thickness, no between-group differences were observed. There were three clusters in left hemisphere and one cluster in right hemisphere showing decreased cortical area in post-traumatic stress disorder patients, compared with trauma controls. Peak voxels of the three clusters in left hemisphere were separately located in superior parietal cortex, insula and rostral anterior cingulate cortex. The finding of reduced surface area of left insula and left rostral anterior cingulate cortex suggests that shrinked surface area in motor vehicle accident victims could act as potential biomarker of subjects at high risk for post-traumatic stress disorder.

  4. Objective and subjective rating of tonal noise radiated from UK wind farms: Pt. 2

    International Nuclear Information System (INIS)

    1996-01-01

    This final report provides data on the assessment of tonal noise radiation from wind turbines in the United Kingdom. Both objective and subjective assessments of the noise pollution from various wind farms are incorporated in the study. Previous subjective tests are verified here using a larger subject and sample size compared to the initial study. The study also aims to produce an objective automatic tonal assessment procedure which identifies tones and broad band masking noise in wind farm radiated noise spectra. (UK)

  5. Stress concentration factors for integral and pad reinforced nozzles in spherical pressure vessels subjected to radial load and moment

    International Nuclear Information System (INIS)

    Soliman, S.F.; Gill, S.S.

    1979-01-01

    Charts are presented giving the elastic stress concentration factors in spherical pressure vessels with pad and integral reinforcement for radial branches subjected to radial load and moment. The effect of all the geometrical parameters is discussed, including the limitations of thin shell theory on the validity of the results. (author)

  6. Male Asian international students' perceived racial discrimination, masculine identity, and subjective masculinity stress: a moderated mediation model.

    Science.gov (United States)

    Wong, Y Joel; Tsai, Pei-Chun; Liu, Tao; Zhu, Qingqing; Wei, Meifen

    2014-10-01

    This study examined male Asian international college students' perceptions of racial discrimination, subjective masculinity stress, centrality of masculine identity, and psychological distress by testing a moderated mediation model. Participants were 160 male Asian international college students from 2 large public universities. Participants' perceived racial discrimination was positively related to their subjective masculinity stress only at high (but not low) levels of masculine identity centrality. Additionally, subjective masculinity stress was positively related to psychological distress, although this association was stronger among those who reported high levels of masculine identity centrality. The authors also detected a moderated mediation effect in which subjective masculinity stress mediated the relationship between perceived racial discrimination and psychological distress only at high (but not low) levels of masculine identity centrality. These findings contribute to the counseling psychology literature by highlighting the connections between race- and gender-related stressors as well as the relevance of masculine identity to an understanding of men's mental health. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  7. Presence of a dog reduces subjective but not physiological stress responses to an analog trauma

    OpenAIRE

    Lass-Hennemann, Johanna; Peyk, Peter; Streb, Markus; Holz, Elena; Michael, Tanja

    2014-01-01

    Dogs are known to have stress and anxiety reducing effects. Several studies have shown that dogs are able to calm people during cognitive and performance stressors. Recently, therapy dogs have been proposed as a treatment adjunct for post-traumatic stress disorder patients. In this study we aimed to investigate, whether dogs also have anxiety- and stress reducing effect during “traumatic stressors.” 80 healthy female participants were randomly assigned to one of four conditions. They were exp...

  8. Question order sensitivity of subjective well-being measures: focus on life satisfaction, self-rated health, and subjective life expectancy in survey instruments.

    Science.gov (United States)

    Lee, Sunghee; McClain, Colleen; Webster, Noah; Han, Saram

    2016-10-01

    This study examines the effect of question context created by order in questionnaires on three subjective well-being measures: life satisfaction, self-rated health, and subjective life expectancy. We conducted two Web survey experiments. The first experiment (n = 648) altered the order of life satisfaction and self-rated health: (1) life satisfaction asked immediately after self-rated health; (2) self-rated health immediately after life satisfaction; and (3) two items placed apart. We examined their correlation coefficient by experimental condition and further examined its interaction with objective health. The second experiment (n = 479) asked life expectancy before and after parental mortality questions. Responses to life expectancy were compared by order using ANOVA, and we examined interaction with parental mortality status using ANCOVA. Additionally, response time and probes were examined. Correlation coefficients between self-rated health and life satisfaction differed significantly by order: 0.313 (life satisfaction first), 0.508 (apart), and 0.643 (self-rated health first). Differences were larger among respondents with chronic conditions. Response times were the shortest when self-rated health was asked first. When life expectancy asked after parental mortality questions, respondents reported considering parents more for answering life expectancy; and respondents with deceased parents reported significantly lower expectancy, but not those whose parents were alive. Question context effects exist. Findings suggest placing life satisfaction and self-rated health apart to avoid artificial attenuation or inflation in their association. Asking about parental mortality prior to life expectancy appears advantageous as this leads respondents to consider parental longevity more, an important factor for true longevity.

  9. Heart rate variability is associated with psychosocial stress in distinct social domains.

    Science.gov (United States)

    Lischke, Alexander; Jacksteit, Robert; Mau-Moeller, Anett; Pahnke, Rike; Hamm, Alfons O; Weippert, Matthias

    2018-03-01

    Psychosocial stress is associated with substantial morbidity and mortality. Accordingly, there is a growing interest in biomarkers that indicate whether individuals show adaptive (i.e., stress-buffering and health-promoting) or maladaptive (i.e., stress-escalating and health-impairing) stress reactions in social contexts. As heart rate variability (HRV) has been suggested to be a biomarker of adaptive behavior during social encounters, it may be possible that inter-individual differences in HRV are associated with inter-individual differences regarding stress in distinct social domains. To test this hypothesis, resting state HRV and psychosocial stress was assessed in 83 healthy community-dwelling individuals (age: 18-35years). HRV was derived from heart rate recordings during spontaneous and instructed breathing to assess the robustness of possible associations between inter-individual differences in HRV and inter-individual differences in psychosocial stress. Psychosocial stress was determined with a self-report questionnaire assessing stress in distinct social domains. A series of categorical and dimensional analyses revealed an association between inter-individual differences in HRV and inter-individual differences in psychosocial stress: Individuals with high HRV reported less stress in social life, but not in family life, work life or everyday life, than individuals with low HRV. On basis of these findings, it may be assumed that individuals with high HRV experience less psychosocial stress than individuals with low HRV. Although such an assumption needs to be corroborated by further findings, it seems to be consistent with previous findings showing that individuals with high HRV suffer less from stress and stress-related disorders than individuals with low HRV. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. A Comparison of Teacher Stress and School Climate across Schools with Different Matric Success Rates

    Science.gov (United States)

    Milner, Karen; Khoza, Harriet

    2008-01-01

    Our aim was to investigate differences in teacher stress and perceptions of school climate among teachers from schools with differing matriculation success rates in the Limpopo province of South Africa. Two schools with matric pass rates of 100% and two schools with matric pass rates of less than 25% were selected from a list of schools provided…

  11. Physical activity, mindfulness meditation, or heart rate variability biofeedback for stress reduction: a randomized controlled trial

    NARCIS (Netherlands)

    van der Zwan, J.E.; de Vente, W.; Huizink, A.C.; Bögels, S.M.; de Bruin, E.I.

    2015-01-01

    In contemporary western societies stress is highly prevalent, therefore the need for stress-reducing methods is great. This randomized controlled trial compared the efficacy of self-help physical activity (PA), mindfulness meditation (MM), and heart rate variability biofeedback (HRV-BF) in reducing

  12. Effect of stress ratio and frequency on fatigue crack growth rate of ...

    Indian Academy of Sciences (India)

    Effect of stress ratio and frequency on the fatigue crack propagation of 2618 aluminium alloy–silicon carbide composite were investigated at ambient temperature. With the first set of specimens, the fatigue crack growth rates were studied at three frequencies of 1 Hz, 5 Hz and 10 Hz at a stress ratio of 0.1 whereas the effects ...

  13. Stress Wave E-Rating of Structural Timber—Size and Moisture Content Effects

    Science.gov (United States)

    Xiping Wang

    2013-01-01

    The objectives of this study were to investigate the influence of cross sectional size and moisture content on stress wave properties of structural timber in various sizes and evaluate the feasibility of using stress wave method to E-rate timber in green conditions. Four different sizes of Douglas-fir (Pseudotsuga menziesii) square timbers were...

  14. Stress management interventions: Improving subjective psychological well-being in the workplace

    OpenAIRE

    Holman, David; Johnson, Sheena; O'Connor, Elinor

    2018-01-01

    In this chapter we provide an overview of stress management interventions (SMI) and review the evidence for their effects on employee stress and well-being. We start by setting out a typology of SMI that classes SMI according to level (i.e., the individual-level or organisation-level) and focus (i.e., a ‘primary’ focus on altering the causes of stress or a ‘secondary’ or ‘tertiary’ focus on reducing stress itself). We then use this typology to describe key types of SMI, after which we review ...

  15. Effects of work stress on ambulatory blood pressure, heart rate, and heart rate variability

    NARCIS (Netherlands)

    Vrijkotte, T. G.; van Doornen, L. J.; de Geus, E. J.

    2000-01-01

    Work stress has repeatedly been associated with an increased risk for cardiovascular disease. This study tested whether this relationship could be explained by exaggerated cardiovascular reactivity to work or impaired recovery in leisure time. Vagal tone was assessed as a possible determinant of

  16. Imbibition, germination and lipid mobilization response by sunflower subjected to salt stress

    International Nuclear Information System (INIS)

    Achakzai, A.K.K.

    2014-01-01

    Salinity is one of the most important abiotic stresses in arid and semi-arid regions that substantially reduce the germination, growth and average yield of major crops. The study was mainly aimed to select the most salt tolerant cultivar of sunflower. Therefore, a pot culture experiment was conducted to study the effects of four different salinity levels having electrical conductivity viz., 1.19, 9.54, 16.48 and 22.38 mS/cm on the imbibition (water uptake), germination and lipid mobilization of seedlings of 4 varieties of sunflower (Helianthus annuus L.) i.e., DO-728, DO-730, Hysun-33 and Suncross-843. Salinity levels were prepared by dissolving calculated amount of NaCl, Na/sub 2/SO/sub 4/, CaCl/sub 2/ and MgCl/sub 2/ (4:10:5:1) in half strength Hoagland culture solution. Imbibition was studied using plastic glasses at an interval of 12 and 24 hours. While germination studies were separately carried out in plastic pots and noted after every 12 hours till 20 days. Whereas, lipid contents of the salt stress germinating seeds were determined at three time intervals viz., 48, 96 and 144 hours of germination. Results showed that there was a linear decrease in imbibition, germination and lipid mobilization as the level of salinity progressively intensifies. Maximum significant reduction in imbibition (12.88%), germination (31.03%) and lipid mobilization (38.62%) is recorded in highest dose of applied salts (22.38 mS/cm). Results further exhibited that maximum significant reduction in imbibition (17.95%) and germination (43.05%) is recorded for variety Suncross-843. While minimum for the same attributes is recorded for variety DO-728. Therefore, in term of imbibitions and germination, DO-728 could be ranked as salt tolerant. Similarly maximum reduction (14.85%) in mobilized lipids is noted for DO-728 and minimum (40.89%) for DO-730. Therefore, in term of lipid mobilization, variety DO-730 could be ranked as salt tolerant and DO-728 as salt sensitive. While remaining 2

  17. Nonlinear Heart Rate Variability features for real-life stress detection. Case study: students under stress due to university examination.

    Science.gov (United States)

    Melillo, Paolo; Bracale, Marcello; Pecchia, Leandro

    2011-11-07

    This study investigates the variations of Heart Rate Variability (HRV) due to a real-life stressor and proposes a classifier based on nonlinear features of HRV for automatic stress detection. 42 students volunteered to participate to the study about HRV and stress. For each student, two recordings were performed: one during an on-going university examination, assumed as a real-life stressor, and one after holidays. Nonlinear analysis of HRV was performed by using Poincaré Plot, Approximate Entropy, Correlation dimension, Detrended Fluctuation Analysis, Recurrence Plot. For statistical comparison, we adopted the Wilcoxon Signed Rank test and for development of a classifier we adopted the Linear Discriminant Analysis (LDA). Almost all HRV features measuring heart rate complexity were significantly decreased in the stress session. LDA generated a simple classifier based on the two Poincaré Plot parameters and Approximate Entropy, which enables stress detection with a total classification accuracy, a sensitivity and a specificity rate of 90%, 86%, and 95% respectively. The results of the current study suggest that nonlinear HRV analysis using short term ECG recording could be effective in automatically detecting real-life stress condition, such as a university examination.

  18. Occupational stress and its association with early retirement and subjective need for occupational rehabilitation in cancer patients.

    Science.gov (United States)

    Böttcher, Hilke M; Steimann, Monika; Rotsch, Martin; Zurborn, Karl-Heinz; Koch, Uwe; Bergelt, Corinna

    2013-08-01

    Returning to work often plays an important role for cancer survivors. Occupational stress may hamper a successful return to work, so cancer survivors should be given the opportunity to address occupational stress issues before returning to work. We investigated the amount of occupational stress among cancer patients and whether it is associated with their well-being, their subjective need for occupational rehabilitation and elevations in their risk of early retirement. At the beginning of rehabilitation, we asked cancer patients to respond to occupation-related and health-related questionnaires. We used t-tests, chi-square tests, and logistic regression analyses to address our research questions. A total of 477 patients participated in the study. Of these, 19% were occupationally stressed, and 26% reported subjective need for occupational rehabilitation. Patients who reported work-related stress had a diminished quality of life, were more likely to report subjective need for occupational rehabilitation (OR = 2.16), and had a higher risk of early retirement (OR = 5.44). Furthermore, cancer patients reported deficits in both active coping abilities and mental stability at work. Because occupational stress is associated with a higher risk of early retirement, both patients and physicians should take work-related problems seriously. Screening patients for occupational stress may help physicians identify patients who are at risk of experiencing problematic work re-entries. Furthermore, the results of the study suggest that cancer patients might have problems maintaining confidence in their abilities to solve work-related problems. Therefore, facilitating the development of a perception of self-efficacy might be an important treatment goal. Copyright © 2012 John Wiley & Sons, Ltd.

  19. Oxidative stress in patients with endemic pemphigus foliaceus and healthy subjects with anti-desmoglein 1 antibodies*

    Science.gov (United States)

    Gutierrez, Ericson Leonardo; Ramos, Willy; Seminario-Vidal, Lucia; Tello, Mercedes; Ronceros, Gerardo; Ortega-Loayza, Alex G.

    2018-01-01

    Background Previous studies have shown oxidative stress in pemphigus vulgaris and pemphigus foliaceus, nevertheless, it remains unknown whether a similar response is characteristic of endemic pemphigus foliaceus in Peru. Objectives To determine the oxidative stress response in endemic pemphigus foliaceus patients and subjects with positive for anti-desmoglein1 antibodies (anti-dsg1) from endemic areas of Peru. Subjects and Methods This is a cross-sectional study. The study population included 21 patients with Endemic Pemphigus foliaceus and 12 healthy subjects with anti-dsg1 antibodies from the Peruvian Amazon (Ucayali), as well as 30 healthy control subjects. Malondialdehyde, an indicator of lipid peroxidation by free radicals, was measured in serum. Results We collected 21 cases of endemic pemphigus foliaceus, 15 of them with active chronic disease and 6 in clinical remission. Serum malondialdehyde values in patients with chronic active evolution and healthy subjects with anti-dsg1 antibodies were statistically higher than those of healthy controls (p<0.001). There was no significant difference between serum values of localized and generalized clinical forms. Study limitations The main limitation of this present study is the small number of patients with endemic pemphigus and healthy subjects positive for desmoglein 1 antibodies. Conclusions The increased serum levels of malondialdehyde in patients with chronic active endemic pemphigus foliaceus and healthy subjects from endemic areas with anti-dsg1 antibodies may suggest a contribution of systemic lipid peroxidation in the pathogenesis of endemic pemphigus foliaceus. PMID:29723379

  20. Stress-intensity factor equations for cracks in three-dimensional finite bodies subjected to tension and bending loads

    Science.gov (United States)

    Newman, J. C., Jr.; Raju, I. S.

    1984-01-01

    Stress intensity factor equations are presented for an embedded elliptical crack, a semielliptical surface crack, a quarter elliptical corner crack, a semielliptical surface crack along the bore of a circular hole, and a quarter elliptical corner crack at the edge of a circular hole in finite plates. The plates were subjected to either remote tension or bending loads. The stress intensity factors used to develop these equations were obtained from previous three dimensional finite element analyses of these crack configurations. The equations give stress intensity factors as a function of parametric angle, crack depth, crack length, plate thickness, and, where applicable, hole radius. The ratio of crack depth to plate thickness ranged from 0 to 1, the ratio of crack depth to crack length ranged from 0.2 to 2, and the ratio of hole radius to plate thickness ranged from 0.5 to 2. The effects of plate width on stress intensity variation along the crack front were also included.

  1. Impacts of obesity and stress on neuromuscular fatigue development and associated heart rate variability.

    Science.gov (United States)

    Mehta, R K

    2015-02-01

    Obesity and stress are independently associated with decrements in neuromuscular functions. The present study examined the interplay of obesity and stress on neuromuscular fatigue and associated heart rate variability (HRV). Forty-eight non-obese (18.5obese (30⩽BMI) adults performed repetitive handgrip exertions at 30% of their maximum strength until exhaustion in the absence and presence of a mental arithmetic stressor. Dependent measures included gold standard fatigue indicators (endurance time and rate of strength loss), perceived effort and mental demand, heart rate and temporal (RMSSD: root mean square of successive differences between N-N intervals) and spectral (LF/HF: ratio of low to high frequency) indices of HRV. Stress negatively affected endurance time (Pobesity × stress interactions were found on endurance time (P=0.0073), rate of strength loss (P=0.027) and perceived effort (P=0.026), indicating that stress increased fatigability, particularly in the obese group. Both obesity (P=0.001) and stress (P=0.033) independently lowered RMSSD. Finally, stress increased LF/HF ratio (P=0.028) and the interaction of stress and obesity (P=0.008) indicated that this was augmented in the obese group. The present study provides the first evidence that stress-related neuromuscular fatigue development is accelerated in obese individuals. In addition, the stress condition resulted in poorer HRV indices, which is indicative of autonomic dysfunction, particularly in the obese group. These findings indicate that workers are more susceptible to fatigue in high-stress work environments, particularly those with higher BMI, which can increase the risk of musculoskeletal injuries as well as cardiovascular diseases in this population.

  2. Influence of cooling rate on residual stress profile in veneering ceramic: measurement by hole-drilling.

    Science.gov (United States)

    Mainjot, Amélie K; Schajer, Gary S; Vanheusden, Alain J; Sadoun, Michaël J

    2011-09-01

    The manufacture of dental crowns and bridges generates residual stresses within the veneering ceramic and framework during the cooling process. Residual stress is an important factor that control the mechanical behavior of restorations. Knowing the stress distribution within the veneering ceramic as a function of depth can help the understanding of failures, particularly chipping, a well-known problem with Yttria-tetragonal-zirconia-polycrystal based fixed partial dentures. The objective of this study is to investigate the cooling rate dependence of the stress profile in veneering ceramic layered on metal and zirconia frameworks. The hole-drilling method, often used for engineering measurements, was adapted for use with veneering ceramic. The stress profile was measured in bilayered disc samples 20 mm in diameter, with a 0.7 mm thick metal or Yttria-tetragonal-zirconia-polycrystal framework and a 1.5mm thick veneering ceramic. Three different cooling procedures were investigated. The magnitude of the stresses in the surface of the veneering ceramic was found to increase with cooling rate, while the interior stresses decreased. At the surface, compressive stresses were observed in all samples. In the interior, compressive stresses were observed in metal samples and tensile in zirconia samples. Cooling rate influences the magnitude of residual stresses. These can significantly influence the mechanical behavior of metal-and zirconia-based bilayered systems. The framework material influenced the nature of the interior stresses, with zirconia samples showing a less favorable stress profile than metal. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  3. Reflex control of heart rate in normal subjects in relation to age: a data base for cardiac vagal neuropathy

    NARCIS (Netherlands)

    Wieling, W.; van Brederode, J. F.; de Rijk, L. G.; Borst, C.; Dunning, A. J.

    1982-01-01

    We examined the heart rate changes induced by forced breathing and by standing up in 133 healthy subjects in the age range 10-65 years in order to establish a data base for studies on parasympathetic heart rate control in autonomic neuropathy. Test results declined with age. Log-transformation was

  4. 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.

  5. 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

  6. Role of insular cortex in visceral hypersensitivity model in rats subjected to chronic stress.

    Science.gov (United States)

    Yi, LiSha; Sun, HuiHui; Ge, Chao; Chen, Ying; Peng, HaiXia; Jiang, YuanXi; Wu, Ping; Tang, YinHan; Meng, QingWei; Xu, ShuChang

    2014-12-30

    Abnormal processing of visceral sensation at the level of the central nervous system has been proven to be important in the pathophysiologic mechanisms of stress related functional gastrointestinal disorders. However, the specific mechanism is still not clear. The insular cortex (IC) was considered as one important visceral sensory area. Moreover, the IC has been shown to be involved in various neuropsychiatric diseases such as panic disorders and post-traumatic stress disorder. However, whether the IC is important in psychological stress related visceral hypersensitivity has not been studied yet. In our study, through destruction of the bilateral IC, we explored whether the IC played a critical role in the formation of visceral hypersensitivity induced by chronic stress on rats. Chronic partial restraint stress was used to establish viscerally hypersensitive rat model. Bilateral IC lesions were generated by N-methyl-D-day (door) aspartate. After a recovery period of 7 days, 14-day consecutive restraint stress was performed. The visceromotor response to colorectal distension was monitored by recording electromyogram to measure rats׳ visceral sensitivity. We found that bilateral insular cortex lesion could markedly inhibit the formation of visceral hypersensitivity induced by chronic stress. The insular cortex plays a critical role in the pathophysiology of stress-related visceral hypersensitivity.

  7. Carotenoid profiling of leaves of selected eggplant accessions subjected to drought stress

    Science.gov (United States)

    This study focused on the quantification of carotenoids of the leaves of African eggplants commonly consumed as leafy and fruit vegetables. The results gave comparative profiles of carotenoids at different growth and developmental stages and under drought stress. Stress was achieved by limiting irri...

  8. Encoding negative events under stress: high subjective arousal is related to accurate emotional memory despite misinformation exposure.

    Science.gov (United States)

    Hoscheidt, Siobhan M; LaBar, Kevin S; Ryan, Lee; Jacobs, W Jake; Nadel, Lynn

    2014-07-01

    Stress at encoding affects memory processes, typically enhancing, or preserving, memory for emotional information. These effects have interesting implications for eyewitness accounts, which in real-world contexts typically involve encoding an aversive event under stressful conditions followed by potential exposure to misinformation. The present study investigated memory for a negative event encoded under stress and subsequent misinformation endorsement. Healthy young adults participated in a between-groups design with three experimental sessions conducted 48 h apart. Session one consisted of a psychosocial stress induction (or control task) followed by incidental encoding of a negative slideshow. During session two, participants were asked questions about the slideshow, during which a random subgroup was exposed to misinformation. Memory for the slideshow was tested during the third session. Assessment of memory accuracy across stress and no-stress groups revealed that stress induced just prior to encoding led to significantly better memory for the slideshow overall. The classic misinformation effect was also observed - participants exposed to misinformation were significantly more likely to endorse false information during memory testing. In the stress group, however, memory accuracy and misinformation effects were moderated by arousal experienced during encoding of the negative event. Misinformed-stress group participants who reported that the negative slideshow elicited high arousal during encoding were less likely to endorse misinformation for the most aversive phase of the story. Furthermore, these individuals showed better memory for components of the aversive slideshow phase that had been directly misinformed. Results from the current study provide evidence that stress and high subjective arousal elicited by a negative event act concomitantly during encoding to enhance emotional memory such that the most aversive aspects of the event are well remembered and

  9. Numerical simulation of mechanisms of deformation,failure and energy dissipation in porous rock media subjected to wave stresses

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The pore characteristics,mineral compositions,physical and mechanical properties of the subarkose sandstones were acquired by means of CT scan,X-ray diffraction and physical tests.A few physical models possessing the same pore characteristics and matrix properties but different porosities compared to the natural sandstones were developed.The 3D finite element models of the rock media with varied porosities were established based on the CT image processing of the physical models and the MIMICS software platform.The failure processes of the porous rock media loaded by the split Hopkinson pressure bar(SHPB) were simulated by satisfying the elastic wave propagation theory.The dynamic responses,stress transition,deformation and failure mechanisms of the porous rock media subjected to the wave stresses were analyzed.It is shown that an explicit and quantitative analysis of the stress,strain and deformation and failure mechanisms of porous rocks under the wave stresses can be achieved by using the developed 3D finite element models.With applied wave stresses of certain amplitude and velocity,no evident pore deformation was observed for the rock media with a porosity less than 15%.The deformation is dominantly the combination of microplasticity(shear strain),cracking(tensile strain) of matrix and coalescence of the cracked regions around pores.Shear stresses lead to microplasticity,while tensile stresses result in cracking of the matrix.Cracking and coalescence of the matrix elements in the neighborhood of pores resulted from the high transverse tensile stress or tensile strain which exceeded the threshold values.The simulation results of stress wave propagation,deformation and failure mechanisms and energy dissipation in porous rock media were in good agreement with the physical tests.The present study provides a reference for analyzing the intrinsic mechanisms of the complex dynamic response,stress transit mode,deformation and failure mechanisms and the disaster

  10. Effect of mineral mixture and antioxidant supplementation on growth, reproductive performance and adaptive capability of Malpura ewes subjected to heat stress.

    Science.gov (United States)

    Sejian, V; Singh, A K; Sahoo, A; Naqvi, S M K

    2014-02-01

    This study was conducted to evaluate the effect of mineral and antioxidant supplementation on growth, reproductive performance and physiological adaptability of heat-stressed Malpura ewes. The study was conducted for a period of 21 days in 21 adult Malpura ewes. The ewes were randomly divided into three groups with seven animals each viz. GI (control; n = 7), GII (heat stress; n = 7) and GIII (heat stress + mineral and antioxidant supplementation; n = 7). The animals were stall fed ad libitum with the diet consisting of 70% roughage and 30% concentrate. GI ewes were maintained under normal controlled condition in the shed, while GII and GIII ewes were subjected to heat stress by exposing them to 42 °C in the climatic chamber. The parameters studied were feed intake (FI), water intake (WI), body weight, body condition score (BCS), physiological, biochemical and endocrine responses. Heat stress significantly altered FI, water intake, BCS, respiration rate and rectal temperature in the afternoon, oestrus duration, estradiol, progesterone, Hb, PCV, plasma glucose, total protein, cortisol, T3 and T4 levels while mineral and antioxidant supplementation ameliorated this heat stress effect on the parameters studied. Further, the adverse effect of heat stress on the productive and reproductive efficiency of Malpura ewes was reduced considerably by mineral mixture and antioxidant supplementation. This is evident from the non-significant difference in BCS, oestrus duration and plasma estradiol between GI and GIII in this study. Hence, it is very pertinent to conclude from this study that mineral mixture and antioxidant supplementation were able to protect Malpura ewes against heat stress. © 2013 Blackwell Verlag GmbH.

  11. Stress-strain properties of railway steel at strain rates of upto 105 per second

    International Nuclear Information System (INIS)

    Hashmi, M.S.J.; Islam, M.N.

    1985-01-01

    This paper presents the stress-strain characteristics of railway steel at strain rates of up to 10 5 /s at room temperature determined by a new technique. In determining the results, account has been taken of the strain-rate variation, the total strain and the strain rate history. The effect of friction, material inertia and temperature rise is also assessed and an empirical constitutive equation describing the strain-rate and strain sensitive flow stress for this type of steel is proposed. (orig.)

  12. Design of a test device for subjecting materials to high strain rates: with application in nuclear area

    Energy Technology Data Exchange (ETDEWEB)

    Todesco, Sergio R.; Mucsi, Cristiano S.; Rossi, Jesualdo L., E-mail: sergio.todesco@usp.br, E-mail: csmucsi@ipen.br, E-mail: jelrossi@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    This paper presents a design of a device to gather characteristic data of materials subjected to high strain rates, this device named after the eminent English engineer Sir Bertram Hopkinson 'Split Hopkinson Pressure Bar', from here will be designated SHPB. More specifically, this work is inseparably linked to the development of packing for transportation of highly radioactive substances as a part to the general scope of a CAPES project in partnership with the CCTM Materials Department of IPEN, Institute of Energy and Nuclear Research, linked to the University of Sao Paulo. The development of the device is part of a scope, and collection of data necessary for the design and construction of this packing. The SHPB device can be divided into two parts, the first part concerning the mechanical design. The second, data collection that is indeed the challenging part of the device, and proper tests. The present paper, specifically, will only deals with the mechanical design of the device, importantly, divided into two parts, the size of the bars, which are the impact bar, the input bar, and the output bar, and the size of the impact device. The sizing of the bars involve knowledge of the concept of elastic waves in solid media for the length of the bars to serve as a wave-guide, which will cause a deformation of the specimen, and enables recording of these waves for data analysis. The impact device must be robust enough to produce the stress wave to deform the specimen, but not to plastically deform the bars, which have to continue throughout the test within the elastic range. (author)

  13. Design of a test device for subjecting materials to high strain rates: with application in nuclear area

    International Nuclear Information System (INIS)

    Todesco, Sergio R.; Mucsi, Cristiano S.; Rossi, Jesualdo L.

    2015-01-01

    This paper presents a design of a device to gather characteristic data of materials subjected to high strain rates, this device named after the eminent English engineer Sir Bertram Hopkinson 'Split Hopkinson Pressure Bar', from here will be designated SHPB. More specifically, this work is inseparably linked to the development of packing for transportation of highly radioactive substances as a part to the general scope of a CAPES project in partnership with the CCTM Materials Department of IPEN, Institute of Energy and Nuclear Research, linked to the University of Sao Paulo. The development of the device is part of a scope, and collection of data necessary for the design and construction of this packing. The SHPB device can be divided into two parts, the first part concerning the mechanical design. The second, data collection that is indeed the challenging part of the device, and proper tests. The present paper, specifically, will only deals with the mechanical design of the device, importantly, divided into two parts, the size of the bars, which are the impact bar, the input bar, and the output bar, and the size of the impact device. The sizing of the bars involve knowledge of the concept of elastic waves in solid media for the length of the bars to serve as a wave-guide, which will cause a deformation of the specimen, and enables recording of these waves for data analysis. The impact device must be robust enough to produce the stress wave to deform the specimen, but not to plastically deform the bars, which have to continue throughout the test within the elastic range. (author)

  14. Lymphocyte subsets are influenced by positivity levels in healthy subjects before and after mild acute stress.

    Science.gov (United States)

    Caprara, Gian Vittorio; Nisini, Roberto; Castellani, Valeria; Vittorio, Pasquali; Alessandri, Guido; Vincenzo, Ziparo; Claudia, Ferlito; Valentina, Germano; Andrea, Picchianti Diamanti; Biondo, Michela Ileen; Milanetti, Francesca; Salerno, Gerardo; Vincenzo, Visco; Mario, Pietrosanti; Aniballi, Eros; Simonetta, Salemi; Angela, Santoni; D'Amelio, Raffaele

    2017-08-01

    In the current study, the possible association of positivity (POS), recently defined as general disposition to view life under positive outlook, with immune markers and post-stress modifications, was analyzed. Circulating lymphocyte subsets and serum cytokine levels were evaluated before and after a standard mild acute stress test, in 41 healthy students, previously selected by a questionnaire for their level of POS (high [POS-H] and low [POS-L]). The CD3 + and CD4 + cell frequency was higher in the POS-H students before and after acute stress. CD4 + subpopulation analysis revealed baseline higher terminally differentiated frequency in the POS-H, whereas higher effector memory frequency was present in the POS-L students. Moreover, the frequency of post-stress B cells was higher in the POS-H students. The mild-stress test was associated to an increase of the IL-10 mean values, while mean values of the other cytokines tested did not change significantly. It is tempting to speculate that IL-10 may work as biomarker of response to acute mild stress and that POS-H may be associated to a better capacity of the immune system to contrast the disturbing effects of mild acute stress. Yet further studies on lymphocyte subset absolute number and function of larger and different populations are needed to definitively prove these preliminary observations. Copyright © 2017 European Federation of Immunological Societies. Published by Elsevier B.V. All rights reserved.

  15. The role of physical activity and heart rate variability for the control of work related stress.

    Science.gov (United States)

    Tonello, Laís; Rodrigues, Fábio B; Souza, Jeniffer W S; Campbell, Carmen S G; Leicht, Anthony S; Boullosa, Daniel A

    2014-01-01

    Physical activity (PA) and exercise are often used as tools to reduce stress and therefore the risk for developing cardiovascular diseases (CVD). Meanwhile, heart rate variability (HRV) has been utilized to assess both stress and PA or exercise influences. The objective of the present review was to examine the current literature in regards to workplace stress, PA/exercise and HRV to encourage further studies. We considered original articles from known databases (PubMed, ISI Web of Knowledge) over the last 10 years that examined these important factors. A total of seven studies were identified with workplace stress strongly associated with reduced HRV in workers. Longitudinal workplace PA interventions may provide a means to improve worker stress levels and potentially cardiovascular risk with mechanisms still to be clarified. Future studies are recommended to identify the impact of PA, exercise, and fitness on stress levels and HRV in workers and their subsequent influence on cardiovascular health.

  16. The role of physical activity and heart rate variability for the control of work related stress

    Directory of Open Access Journals (Sweden)

    Laís eTonello

    2014-02-01

    Full Text Available Physical activity (PA and exercise are often used as tools to reduce stress and therefore the risk for developing cardiovascular diseases. Meanwhile, heart rate variability (HRV has been utilised to assess both stress and PA or exercise influences. The objective of the present mini review was to examine the current literature in regards to workplace stress, PA/exercise and HRV to encourage further studies. We considered original articles from known databases (PubMed, ISI Web of Knowledge over the last 10 years that examined these important factors. A total of 7 studies were identified with workplace stress strongly associated with reduced HRV in workers. Longitudinal workplace PA interventions may provide a means to improve worker stress levels and potentially cardiovascular risk with mechanisms still to be clarified. Future studies are recommended to identify the impact of PA, exercise and fitness on stress levels and HRV in workers and their subsequent influence on cardiovascular health.

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

    Science.gov (United States)

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

    2014-03-01

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

  18. Voltage stress effects on microcircuit accelerated life test failure rates

    Science.gov (United States)

    Johnson, G. M.

    1976-01-01

    The applicability of Arrhenius and Eyring reaction rate models for describing microcircuit aging characteristics as a function of junction temperature and applied voltage was evaluated. The results of a matrix of accelerated life tests with a single metal oxide semiconductor microcircuit operated at six different combinations of temperature and voltage were used to evaluate the models. A total of 450 devices from two different lots were tested at ambient temperatures between 200 C and 250 C and applied voltages between 5 Vdc and 15 Vdc. A statistical analysis of the surface related failure data resulted in bimodal failure distributions comprising two lognormal distributions; a 'freak' distribution observed early in time, and a 'main' distribution observed later in time. The Arrhenius model was shown to provide a good description of device aging as a function of temperature at a fixed voltage. The Eyring model also appeared to provide a reasonable description of main distribution device aging as a function of temperature and voltage. Circuit diagrams are shown.

  19. Parenting stress and external stressors as predictors of maternal ratings of child adjustment.

    Science.gov (United States)

    Ostberg, Monica; Hagekull, Berit

    2013-06-01

    This study sought to disentangle the effects of different kinds of stress on maternal ratings of child externalizing and internalizing problems, social inhibition, and social competence, with a primary focus on parenting stress. The relations were explored in a sample consisting of mothers of 436 children (Mage  = 7 years) in Sweden. Half the sample had had early clinical contacts during infancy due to child regulation problems, and the rest were mothers without known such early contacts. Demographic factors, family stressors, and parenting stress were examined in stress - adjustment models. Family stressors were clinical contact during infancy, current child and parent health problems, recent negative life events, and insufficient social support. Parenting stress as a mediator of the effect of other stressors on rated child adjustment was tested as was social support as a moderator of the effect of parenting stress on adjustment. The results showed that a higher parenting stress level was associated with maternal ratings of more externalizing and internalizing behaviors, more social inhibition, and lower social competence. Other family stressors and background variables were also found to be of importance, mainly for externalizing and internalizing problems and to some extent for social competence. Social inhibition had a unique relation to parenting stress only. Parenting stress mediated effects of other stressors in twelve models, whereas social support had no moderating effect on the link between parenting stress and child adjustment. Thus, parenting stress seems to be an important overarching construct. Clinical implications are proposed. © 2013 The Authors. Scandinavian Journal of Psychology © 2013 The Scandinavian Psychological Associations.

  20. Determination of stresses in gas-turbine disks subjected to plastic flow and creep

    Science.gov (United States)

    Millenson, M B; Manson, S S

    1948-01-01

    A finite-difference method previously presented for computing elastic stresses in rotating disks is extended to include the computation of the disk stresses when plastic flow and creep are considered. A finite-difference method is employed to eliminate numerical integration and to permit nontechnical personnel to make the calculations with a minimum of engineering supervision. Illustrative examples are included to facilitate explanation of the procedure by carrying out the computations on a typical gas-turbine disk through a complete running cycle. The results of the numerical examples presented indicate that plastic flow markedly alters the elastic-stress distribution.

  1. Ethnicity, work-related stress and subjective reports of health by migrant workers: a multi-dimensional model.

    Science.gov (United States)

    Capasso, Roberto; Zurlo, Maria Clelia; Smith, Andrew P

    2018-02-01

    This study integrates different aspects of ethnicity and work-related stress dimensions (based on the Demands-Resources-Individual-Effects model, DRIVE [Mark, G. M., and A. P. Smith. 2008. "Stress Models: A Review and Suggested New Direction." In Occupational Health Psychology, edited by J. Houdmont and S. Leka, 111-144. Nottingham: Nottingham University Press]) and aims to test a multi-dimensional model that combines individual differences, ethnicity dimensions, work characteristics, and perceived job satisfaction/stress as independent variables in the prediction of subjectives reports of health by workers differing in ethnicity. A questionnaire consisting of the following sections was submitted to 900 workers in Southern Italy: for individual and cultural characteristics, coping strategies, personality behaviours, and acculturation strategies; for work characteristics, perceived job demands and job resources/rewards; for appraisals, perceived job stress/satisfaction and racial discrimination; for subjective reports of health, psychological disorders and general health. To test the reliability and construct validity of the extracted factors referred to all dimensions involved in the proposed model and logistic regression analyses to evaluate the main effects of the independent variables on the health outcomes were conducted. Principal component analysis (PCA) yielded seven factors for individual and cultural characteristics (emotional/relational coping, objective coping, Type A behaviour, negative affectivity, social inhibition, affirmation/maintenance culture, and search identity/adoption of the host culture); three factors for work characteristics (work demands, intrinsic/extrinsic rewards, and work resources); three factors for appraisals (perceived job satisfaction, perceived job stress, perceived racial discrimination) and three factors for subjective reports of health (interpersonal disorders, anxious-depressive disorders, and general health). Logistic

  2. Cool-down flow-rate limits imposed by thermal stresses in LNG pipelines

    Science.gov (United States)

    Novak, J. K.; Edeskuty, F. J.; Bartlit, J. R.

    Warm cryogenic pipelines are usually cooled to operating temperature by a small, steady flow of the liquid cryogen. If this flow rate is too high or too low, undesirable stresses will be produced. Low flow-rate limits based on avoidance of stratified two-phase flow were calculated for pipelines cooled with liquid hydrogen or nitrogen. High flow-rate limits for stainless steel and aluminum pipelines cooled by liquid hydrogen or nitrogen were determined by calculating thermal stress in thick components vs flow rate and then selecting some reasonable stress limits. The present work extends these calculations to pipelines made of AISI 304 stainless steel, 6061 aluminum, or ASTM A420 9% nickel steel cooled by liquid methane or a typical natural gas. Results indicate that aluminum and 9% nickel steel components can tolerate very high cool-down flow rates, based on not exceeding the material yield strength.

  3. Resident intruder paradigm-induced aggression relieves depressive-like behaviors in male rats subjected to chronic mild stress

    Science.gov (United States)

    Wei, Sheng; Ji, Xiao-wei; Wu, Chun-ling; Li, Zi-fa; Sun, Peng; Wang, Jie-qiong; Zhao, Qi-tao; Gao, Jie; Guo, Ying-hui; Sun, Shi-guang; Qiao, Ming-qi

    2014-01-01

    Background Accumulating epidemiological evidence shows that life event stressors are major vulnerability factors for psychiatric diseases such as major depression. It is also well known that the resident intruder paradigm (RIP) results in aggressive behavior in male rats. However, it is not known how resident intruder paradigm-induced aggression affects depressive-like behavior in isolated male rats subjected to chronic mild stress (CMS), which is an animal model of depression. Material/Methods Male Wistar rats were divided into 3 groups: non-stressed controls, isolated rats subjected to the CMS protocol, and resident intruder paradigm-exposed rats subjected to the CMS protocol. Results In the sucrose intake test, ingestion of a 1% sucrose solution by rats in the CMS group was significantly lower than in control and CMS+RIP rats after 3 weeks of stress. In the open-field test, CMS rats had significantly lower open-field scores compared to control rats. Furthermore, the total scores given the CMS group were significantly lower than in the CMS+RIP rats. In the forced swimming test (FST), the immobility times of CMS rats were significantly longer than those of the control or CMS+RIP rats. However, no differences were observed between controls and CMS+RIP rats. Conclusions Our data show that aggressive behavior evoked by the resident intruder paradigm could relieve broad-spectrum depressive-like behaviors in isolated adult male rats subjected to CMS. PMID:24911067

  4. Immediate effects of chest physiotherapy on hemodynamic, metabolic, and oxidative stress parameters in subjects with septic shock.

    Science.gov (United States)

    dos Santos, Rafael S; Donadio, Márcio V F; da Silva, Gabriela V; Blattner, Clarissa N; Melo, Denizar A S; Nunes, Fernanda B; Dias, Fernando S; Squizani, Eamim D; Pedrazza, Leonardo; Gadegast, Isabella; de Oliveira, Jarbas R

    2014-09-01

    Septic shock presents as a continuum of infectious events, generating tissue hypoxia and hypovolemia, and increased oxidative stress. Chest physiotherapy helps reduce secretion, improving dynamic and static compliance, as well as improving secretion clearance and preventing pulmonary complications. The purpose of this study was to evaluate the immediate effect of chest physiotherapy on hemodynamic, metabolic, inflammatory, and oxidative stress parameters in subjects in septic shock. We conducted a quasi-experimental study in 30 subjects in septic shock, who underwent chest physiotherapy, without associated heart diseases and with vasopressors stress were evaluated before and 15 min after physiotherapy. Thirty subjects with a mean age of 61.8 ± 15.9 y and Sequential Organ Failure Assessment of 8 (range 6-10) were included. Chest physiotherapy caused a normalization of pH (P = .046) and P(aCO2) (P = .008); reduction of lactate (P = .001); and an increase in P(aO2) (P = .03), arterial oxygen saturation (P = .02), and P(aO2)/F(IO2) (P = .034), 15 min after it was applied. The results indicate that chest physiotherapy has immediate effects, improving oxygenation and reducing lactate and oxidative damage in subjects in septic shock. However, it does not cause alterations in the inflammatory and hemodynamic parameters. Copyright © 2014 by Daedalus Enterprises.

  5. Biofluid metabotyping of occupationally exposed subjects to air pollution demonstrates high oxidative stress and deregulated amino acid metabolism

    Science.gov (United States)

    Pradhan, Surya Narayan; Das, Aleena; Meena, Ramovatar; Nanda, Ranjan Kumar; Rajamani, Paulraj

    2016-10-01

    Occupational exposure to air pollution induces oxidative stress and prolonged exposure increases susceptibility to cardiovascular and respiratory diseases in several working groups. Biofluid of these subjects may reflect perturbed metabolic phenotypes. In this study we carried out a comparative molecular profiling study using parallel biofluids collected from subjects (n = 85) belonging to auto rickshaw drivers (ARD), traffic cops (TC) and office workers (OW). Higher levels of oxidative stress and inflammation markers in serum of ARD subjects were observed as compared to OW and TC. Uni and multivariate analyses of metabolites identified in urine by 1H NMR revealed 11 deregulated molecules in ARD subjects and involved in phenylalanine, histidine, arginine and proline metabolism. Despite contribution of confounding factors like exposure period, dietary factors including smoking and alcohol status, our results demonstrate existence of exposure specific metabotypes in biofluids of ARD, OW and TC groups. Monitoring serum oxidative stress and inflammation markers and urine metabolites by NMR may be useful to characterize perturbed metabolic phenotypes in populations exposed to urban traffic air pollution.

  6. The importance of the strain rate and creep on the stress corrosion cracking mechanisms and models

    International Nuclear Information System (INIS)

    Aly, Omar F.; Mattar Neto, Miguel; Schvartzman, Monica M.A.M.

    2011-01-01

    Stress corrosion cracking is a nuclear, power, petrochemical, and other industries equipment and components (like pressure vessels, nozzles, tubes, accessories) life degradation mode, involving fragile fracture. The stress corrosion cracking failures can produce serious accidents, and incidents which can put on risk the safety, reliability, and efficiency of many plants. These failures are of very complex prediction. The stress corrosion cracking mechanisms are based on three kinds of factors: microstructural, mechanical and environmental. Concerning the mechanical factors, various authors prefer to consider the crack tip strain rate rather than stress, as a decisive factor which contributes to the process: this parameter is directly influenced by the creep strain rate of the material. Based on two KAPL-Knolls Atomic Power Laboratory experimental studies in SSRT (slow strain rate test) and CL (constant load) test, for prediction of primary water stress corrosion cracking in nickel based alloys, it has done a data compilation of the film rupture mechanism parameters, for modeling PWSCC of Alloy 600 and discussed the importance of the strain rate and the creep on the stress corrosion cracking mechanisms and models. As derived from this study, a simple theoretical model is proposed, and it is showed that the crack growth rate estimated with Brazilian tests results with Alloy 600 in SSRT, are according with the KAPL ones and other published literature. (author)

  7. A preliminary investigation of workplace stress in platinum miners using subjective and objective measures

    CSIR Research Space (South Africa)

    Edwards, A

    2011-04-01

    Full Text Available Workplace stress in the mining environment will affect health and safety outcomes in the workforce that could result in accidents and injuries, as well as poorer worker health. Increased knowledge of the specific characteristics and incidence...

  8. [Effect of a hypocaloric diet in the oxidative stress in obese subjects without prescription of exercise and antioxidants].

    Science.gov (United States)

    Gutiérrez, Liliana; García, José R; Rincón, María de Jesús; Ceballos, Guillermo M; Olivares, Ivonne M

    2015-07-06

    Obesity is characterized by a generalized increase of adipose tissue, high production of adipocytokines and presence of oxidative systemic stress. The objective of this study was to evaluate the changes generated in the oxidative stress and anthropometric parameters in obese subjects by the prescription of a hypocaloric diet in combination with moderate aerobic exercise and supplementation with antioxidants. Oxidative damage was determined in the plasma from 30 normal weight and 30 obese subjects. Three groups of treatment were established: Hypocaloric diet (HD), HD plus moderate aerobic exercise (HDE) and HDE plus antioxidants (DHEA). Biomarkers of oxidative stress (thiobarbituric acid reactive substances [TBARS], carbonyl groups, dityrosine) and anthropometric parameters were determined. Higher values of biomarkers of oxidative damage were observed in obese (TBARS 13.74 ± 1.2 μM; carbonyl groups 0.89 ± 0.04 nmol of osazone/mg of protein; dityrosine 478.9 ± 27.4 RFU/mg of protein) in comparison to normal weight subjects (TBARS 7.08 ± 0.8 μM; carbonyl groups 0.65 ± 0.04 nmol of osazone/mg of protein; dityrosine 126.3 ± 12.6 RFU/mg of protein), thus showing the presence of an oxidative damage. The prescription of HD decreased the oxidative damage and anthropometric parameters in the obese subjects. We did not observe additional benefit effects on these determinations with HDE or HDEA treatments. We demonstrated that an HD decreases the oxidative damage in obese subjects. Oxidative stress is an important factor in the development of comorbidity in obesity. Therefore, the prescription of a HD could be a key issue in the treatment of the disease. Copyright © 2013 Elsevier España, S.L.U. All rights reserved.

  9. The interactive association between heat shock factor 1 and heat shock proteins in primary myocardial cells subjected to heat stress.

    Science.gov (United States)

    Tang, Shu; Chen, Hongbo; Cheng, Yanfen; Nasir, Mohammad Abdel; Kemper, Nicole; Bao, Endong

    2016-01-01

    Heat shock factor 1 (HSF1) is a heat shock transcription factor that rapidly induces heat shock gene transcription following thermal stress. In this study, we subjected primary neonatal rat myocardial cells to heat stress in vitro to create a model system for investigating the trends in expression and association between various heat shock proteins (HSPs) and HSF1 under adverse environmental conditions. After the cells were subjected to heat stress at 42˚C for different periods of time, HSP and HSF1 mRNA and protein levels were detected by qPCR and western blot analysis in the heat-stressed cells. The HSF1 expression levels significantly increased in the cells following 120 min of exposure to heat stess compared to the levels observed at the beginning of heat stress exposure. HSP90 followed a similar trend in expression to HSF1, whereas HSP70 followed an opposite trend. However, no significant changes were observed in the crystallin, alpha B (CRYAB, also known as HSP beta-5) expression levels during the 480‑min period of exposure to heat stress. The interaction between the HSPs and HSF1 was analyzed by STRING 9.1, and it was found that HSF1 interacted with HSP90 and HSP70, and that it did not play a role in regulating CRYAB expression. Based on our findings, HSP70 may suppress HSF1 in rat myocardial cells under conditions of heat stress. Furthermore, our data demonstrate that HSF1 is not the key factor for all HSPs, and this was particularly the case for CRYAB.

  10. Structure/property relations of aluminum under varying rates and stress states

    Energy Technology Data Exchange (ETDEWEB)

    Tucker, Matthew T [Los Alamos National Laboratory; Horstemeyer, Mark F [MISSISSIPPI STATE UNIV; Whittington, Wilburn R [MISSISSIPPI STATE UNIV; Solanki, Kiran N [MISSISSIPPI STATE UNIV.

    2010-11-19

    In this work we analyze the plasticity, damage, and fracture characteristics of three different processed aluminum alloys (rolled 5083-H13, cast A356-T6, and extruded 6061-T6) under varying stress states (tension, compression, and torsion) and strain rates (0.001/, 1/s., and 1000/s). The stress state difference had more of a flow stress effect than the applied strain rates for those given in this study (0.001/sec up to 1000/sec). The stress state and strain rate also had a profound effect on the damage evolution of each aluminum alloy. Tension and torsional straining gave much greater damage nucleation rates than compression. Although the damage of all three alloys was found to be void nucleation dominated, the A356-T6 and 5083-H131 aluminum alloys incurred void damage via micron scale particles where the 6061-T6 aluminum alloy incurred void damage from two scales, micron-scale particles and nanoscale precipitates. Having two length scales of particles that participated in the damage evolution made the 6061-T6 incur a strain rate sensitive damage rate that was different than the other two aluminum alloys. Under tension, as the strain rate increased, the 6061-T6 aluminum alloy's void nucleation rate decreased, but the A356-T6 and 5083-H131 aluminum alloys void nucleation rate increased.

  11. Presence of a dog reduces subjective but not physiological stress responses to an analogue trauma

    OpenAIRE

    Johanna eLass-Hennemann; Peter ePeyk; Markus eStreb; Elena eHolz; Tanja eMichael

    2014-01-01

    Dogs are known to have stress and anxiety reducing effects. Several studies have shown that dogs are able to calm people during cognitive and performance stressors. Recently, therapy dogs have been proposed as a treatment adjunct for PTSD patients. In this study we aimed to investigate, whether dogs also have anxiety- and stress reducing effect during traumatic stressors. 80 healthy female participants were randomly assigned to one of 4 conditions. They were exposed to a traumatic film clip (...

  12. Study of a new alternative antioxidant in soybean plants subjected to abiotic stress

    International Nuclear Information System (INIS)

    Zilli, C.; Santa Cruz, D.; Caggiano, E.; Romanello, M.; Tomaro, M.; Balestrasse, K.

    2010-01-01

    We have recently, demonstrated that the induction of heme oxygenase-1 (HO-1) plays a protective role for soybean plants against oxidative stress produced by cadmium and UV-B radiation. At this moment we propose to investigate if the enzyme has the same capacity against another type of abiotic stress, such as drought, for to demonstrate that heme oxygenase acts as an enzyme of plant antioxidant defense system under several different stress situations, as occur in mammalian tissues. To carry out this objective we propose to study, in leaf, root and nodule of soybean plants, the oxidative stress generation; the behavior of classical antioxidant system; the behavior of HO-1 activity and protein and gene expression; the effect of its reaction products and inhibitors on the oxidative stress parameters; the signaling mechanism that produce HO-1 induction and the immunohistochemistry localization of the enzyme in the different plant tissues. The results obtained let us undoubtedly demonstrate the involvement of HO-1 in the antioxidant defense system in plants. This finding will allow the increase in the knowledge of the defense mechanisms in interesting economic plants for our country, such as soybean, and against drought, an abiotic stress considered one of the most important factors limiting plant performance and yield worldwide. (authors)

  13. Effect of a stress management program on subjects with neck pain: A pilot randomized controlled trial.

    Science.gov (United States)

    Metikaridis, T Damianos; Hadjipavlou, Alexander; Artemiadis, Artemios; Chrousos, George; Darviri, Christina

    2016-05-20

    Studies have shown that stress is implicated in the cause of neck pain (NP). The purpose of this study is to examine the effect of a simple, zero cost stress management program on patients suffering from NP. This study is a parallel-type randomized clinical study. People suffering from chronic non-specific NP were chosen randomly to participate in an eight week duration program of stress management (N= 28) (including diaphragmatic breathing, progressive muscle relaxation) or in a no intervention control condition (N= 25). Self-report measures were used for the evaluation of various variables at the beginning and at the end of the eight-week monitoring period. Descriptive and inferential statistic methods were used for the statistical analysis. At the end of the monitoring period, the intervention group showed a statistically significant reduction of stress and anxiety (p= 0.03, p= 0.01), report of stress related symptoms (p= 0.003), percentage of disability due to NP (p= 0.000) and NP intensity (p= 0.002). At the same time, daily routine satisfaction levels were elevated (p= 0.019). No statistically significant difference was observed in cortisol measurements. Stress management has positive effects on NP patients.

  14. Investigations on GSK-3β/NF-kB signaling in stress and stress adaptive behavior in electric foot shock subjected mice.

    Science.gov (United States)

    Bali, Anjana; Jaggi, Amteshwar Singh

    2016-04-01

    The present study was designed to explore the role of GSK-3β and NF-kB signaling in electric foot shock-induced stress and stress adaptation. Mice were subjected to foot shocks of 0.5mA intensity and 1s duration of 1h to produce acute stress. Animals were exposed to the same stressor for 5 days to induce stress adaptation. The behavioral alterations were assessed using the actophotometer, hole board, open field and social interaction tests. The serum corticosterone levels were assessed as a marker of the HPA axis. The levels of total GSK-3β, p-GSK-3β-S9 and p-NF-kB were determined in the hippocampus, frontal cortex and amygdala. Acute electric foot shock stress produced behavioral and biochemical changes; decreased the levels of p-GSK-3β-S9, produced no change in total GSK-3β levels and increased p-NF-kB levels in the brain. However, repeated exposure of foot shock stress restored the behavioral and biochemical changes along with normalization of p-GSK-3β-S9 and p-NF-kB levels. Administration of AR-A01, a selective GSK-3β inhibitor, or diethyldithiocarbamic acid (DDTC), a selective NF-kB inhibitor, diminished acute stress-induced behavioral and biochemical changes. Furthermore, AR-A014418 normalized acute stress-induced alterations in p-GSK-3β-S9 and p-NF-kB levels, however, DDTC selectively restored NF-kB levels without any change in p-GSK-3β-S9 levels. It probably suggests that NF-kB is a downstream mediator of the GSK-3 signaling cascade. It may conclude that acute stress associated decrease in p-GSK-3β-S9 and increase in p-NF-kB levels in the brain contribute in the development of behavioral and biochemical alterations and normalization of GSK-3β/NF-kB signaling may contribute in stress adaptive behavior in response to repeated electric foot shock-subjected mice. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. The Impact of Employment and Self-Rated Economic Condition on the Subjective Well-Being of Older Korean Immigrants.

    Science.gov (United States)

    Kim, Bum Jung; Lee, Yura; Sangalang, Cindy; Harris, Lesley M

    2015-09-01

    Extensive research has demonstrated a relationship between socioeconomic factors and health among older adults, yet fewer studies have explored this relationship with older immigrants. This study aims to examine the influence of employment and self-rated economic condition on the subjective well-being of older Korean immigrants in the United States. Data were drawn from a cross-sectional study of 205 older Korean immigrants, aged 65 to 90, in Los Angeles County. Hierarchical regression was employed to explore the independent and interactive effects of employment status and self-rated economic condition. The study found that employment and self-rated economic status were positively associated with subjective well-being. Also, the interaction between employment and self-rated economic status was significantly associated with higher levels of subjective well-being, such that the influence of self-rated economic condition was stronger for unemployed older Korean immigrants compared with those who were employed. This population-based study provides empirical evidence that employment and self-rated economic condition are directly associated with subjective well-being for older Korean immigrants. © The Author(s) 2015.

  16. Heart rate variability during acute psychosocial stress: A randomized cross-over trial of verbal and non-verbal laboratory stressors.

    Science.gov (United States)

    Brugnera, Agostino; Zarbo, Cristina; Tarvainen, Mika P; Marchettini, Paolo; Adorni, Roberta; Compare, Angelo

    2018-05-01

    Acute psychosocial stress is typically investigated in laboratory settings using protocols with distinctive characteristics. For example, some tasks involve the action of speaking, which seems to alter Heart Rate Variability (HRV) through acute changes in respiration patterns. However, it is still unknown which task induces the strongest subjective and autonomic stress response. The present cross-over randomized trial sought to investigate the differences in perceived stress and in linear and non-linear analyses of HRV between three different verbal (Speech and Stroop) and non-verbal (Montreal Imaging Stress Task; MIST) stress tasks, in a sample of 60 healthy adults (51.7% females; mean age = 25.6 ± 3.83 years). Analyses were run controlling for respiration rates. Participants reported similar levels of perceived stress across the three tasks. However, MIST induced a stronger cardiovascular response than Speech and Stroop tasks, even after controlling for respiration rates. Finally, women reported higher levels of perceived stress and lower HRV both at rest and in response to acute psychosocial stressors, compared to men. Taken together, our results suggest the presence of gender-related differences during psychophysiological experiments on stress. They also suggest that verbal activity masked the vagal withdrawal through altered respiration patterns imposed by speaking. Therefore, our findings support the use of highly-standardized math task, such as MIST, as a valid and reliable alternative to verbal protocols during laboratory studies on stress. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. AC loss characteristics of Bi2223/Ag sheathed tape wires subjected to mechanical strains and stresses

    International Nuclear Information System (INIS)

    Tsukamoto, Osami; Li, Z

    2007-01-01

    The influence of uniaxial tensile stress-strain on the AC loss characteristics of multifilamentary Bi2223/Ag sheathed tape wires was investigated. The uniaxial tensile stress-strain was applied to the sample wire in liquid nitrogen at atmospheric pressure, and the AC losses (transport, magnetization and total losses) were measured by an electric method. Two kinds of wire, oxide-dispersion strengthened Ag-alloy sheathed and Ag-alloy sheathed wires, were tested. The stress-strain curves of the tested wires were divided in three regions, i.e. elastic deformation, continuous plastic deformation and serrated-like plastic deformation regions, though the ranges of those regions were different for different kinds of wire. In the elastic and continuous plastic regions, the stress-strain curve was smooth and continuous, and in the serrated-like plastic region, the curve was rough. In the serrated-like plastic region, the wires kept elongating, while increase of the tensile stress was suspended. Dependences of the critical currents on the stress-strain were generally as follows. While decreases of the wire critical currents were in the range of less than 4% of the original values of the no-stress condition, the critical currents of the wires were reversible, that is, the critical currents recovered the original values at zero stress when the stress were released, regardless of whether the wires were in the elastic or continuous plastic region. In the continuous plastic region, the critical currents decreased up to 10%-15% of the original values and the critical currents were irreversible when the degradations of the critical currents exceeded about 4%. In the serrated-like plastic regions, the critical currents were more severely degraded. The AC loss characteristics of the wires are different in those regions. In the elastic and continuous plastic regions, the absolute values of AC losses were dependent on the stress-strain. However, the dependences of those normalized

  18. Approximate entropy and point correlation dimension of heart rate variability in healthy subjects

    DEFF Research Database (Denmark)

    Storella, R J; Wood, H W; Mills, K M

    1999-01-01

    The contribution of nonlinear dynamics to heart rate variability in healthy humans was examined using surrogate data analysis. Several measures of heart rate variability were used and compared. Heart rates were recorded for three hours and original data sets of 8192 R-R intervals created. For each...... original data set (n = 34), three surrogate data sets were made by shuffling the order of the R-R intervals while retaining their linear correlations. The difference in heart rate variability between the original and surrogate data sets reflects the amount of nonlinear structure in the original data set....... Heart rate variability was analyzed by two different nonlinear methods, point correlation dimension and approximate entropy. Nonlinearity, though under 10 percent, could be detected with both types of heart rate variability measures. More importantly, not only were the correlations between...

  19. Subjective assessment of chimpanzee (Pan troglodytes) personality: reliability and stability of trait ratings.

    Science.gov (United States)

    Dutton, Diane M

    2008-10-01

    A 46-item rating scale was used to obtain personality ratings from 75 captive chimpanzees (Pan troglodytes) from 7 zoological parks. Factor analysis revealed five personality dimensions similar to those found in previous research on primate personality: Agreeableness, Dominance, Neuroticism, Extraversion and Intellect. There were significant sex and age differences in ratings on these dimensions, with males rated more highly on Dominance and older chimpanzees rated as more agreeable but less extraverted than younger chimpanzees. Interobserver agreement for most individual trait items was high, but tended to be less reliable for trait terms expressing more subtle social or cognitive abilities. Personality ratings for one zoo were found to be largely stable across a 3-year period, but highlighted the effects of environmental factors on the expression of personality in captive chimpanzees.

  20. Study on the Leak Rate Estimation of SG Tubes and Residual Stress Estimation based on Plastic Deformation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Jin; Chang, Yoon Suk; Lee, Dock Jin; Lee, Tae Rin; Choi, Shin Beom; Jeong, Jae Uk; Yeum, Seung Won [Sungkyunkwan University, Seoul (Korea, Republic of)

    2009-02-15

    In this research project, a leak rate estimation model was developed for steam generator tubes with through wall cracks. The modelling was based on the leak data from 23 tube specimens. Also, the procedure of finite element analysis was developed for residual stress calculation of dissimilar metal weld in a bottom mounted instrumentation. The effect of geometric variables related with the residual stress in penetration weld part was investigated by using the developed analysis procedure. The key subjects dealt in this research are: 1. Development of leak rate estimation model for steam generator tubes with through wall cracks 2. Development of the program which can perform the structure and leakage integrity evaluation for steam generator tubes 3. Development of analysis procedure for bottom mounted instrumentation weld residual stress 4. Analysis on the effects of geometric variables on weld residual stress It is anticipated that the technologies developed in this study are applicable for integrity estimation of steam generator tubes and weld part in NPP.

  1. During stress, heart rate variability moderates the impact of childhood adversity in women with breast cancer.

    Science.gov (United States)

    Tell, Dina; Mathews, Herbert L; Burr, Robert L; Witek Janusek, Linda

    2018-03-01

    Childhood adversity has long-lasting neuro-biological effects that can manifest as exaggerated stress responsivity to environmental challenge. These manifestations include a dysregulated hypothalamic-pituitary-adrenocortical (HPA) axis as well as increased levels of inflammatory mediators in response to stress. In this investigation, vagal parasympathetic activity was assessed for its capacity to moderate the relationship between childhood adversity and stress responsivity (cortisol and inflammation) during an acute laboratory challenge (Trier Social Stress Test-TSST). Thirty women recently diagnosed with breast cancer underwent the TSST during which their heart rate was recorded and saliva samples collected for measurement of cortisol and the proinflammatory cytokine, IL-6. Vagal activity during the TSST was calculated as the high-frequency (HF) component of heart rate variability (HRV). Vagal activity during the TSST moderated the effect of childhood adversity on both the cortisol and the IL-6 response. Women who had lower vagal stress-reactivity during the TSST and reported greater childhood adversity showed a larger rise in cortisol and IL-6 when compared to women with lower childhood adversity. The findings demonstrate that women with exposure to childhood adversity and low vagal stress-reactivity (reduced parasympathetic activity) exhibit an elevated stress response characterized by greater cortisol and proinflammatory cytokine release. Inflammatory burden and HPA dysregulation subsequent to stress may impair cancer control.

  2. Effects of strain rate, stress condition and environment on iodine embrittlement of Ziracloy-2

    International Nuclear Information System (INIS)

    Une, K.

    1979-01-01

    Iodine stress corrosion cracking (SCC) susceptibility of Zircaloy became higher with decreasing strain rate. Critical strain rate, below which high SCC severity was observed, substantially depended on Zircaloy stress condition. This strain rate (7 x 10 -3 min -1 ) under plane strain condition was about 3.5 times as fast as that (2 x 10 -3 min -1 ) under uniaxial condition. The maximum iodine embrittlement in Zircaloy was found in stress ratio α (axial/tangential stress) range of 0.5 to 0.7. No embrittlement occurred at α = infinity because of its texture effect. The SCC fracture stresses were about 39 kg/mm 2 for unirradiated and stress-relieved material, and about 34 kg/mm 2 for recrystallized material, whose ratios to yield strength of each material were 0.8 and 1.2. Impurity gases of oxygen and moisture in the iodine had the effects of reducing Zircaloy SCC susceptibility. Stress-relieved material was more sensitive to environmental impurities than recrystallized material

  3. Neighborhood blight, stress, and health: a walking trial of urban greening and ambulatory heart rate

    Science.gov (United States)

    Eugenia C. South; Michelle C. Kondo; Rose A. Cheney; Charles C. Branas

    2015-01-01

    We measured dynamic stress responses using ambulatory heart rate monitoring as participants in Philadelphia, Pennsylvania walked past vacant lots before and after a greening remediation treatment of randomly selected lots. Being in view of a greened vacant lot decreased heart rate significantly more than did being in view of a nongreened vacant lot or not in view of...

  4. Evaluation of dietary betaine in lactating Holstein cows subjected to heat stress.

    Science.gov (United States)

    Hall, L W; Dunshea, F R; Allen, J D; Rungruang, S; Collier, J L; Long, N M; Collier, R J

    2016-12-01

    Betaine (BET), a natural, organic osmolyte, improves cellular efficiency by acting as a chaperone, refolding denatured proteins. To test if dietary BET reduced the effect of heat stress (HS) in lactating dairy cows, multiparous, lactating Holstein cows (n=24) were blocked by days in milk (101.4±8.6 d) and randomly assigned to 1 of 3 daily intakes of dietary BET: the control (CON) group received no BET, mid intake (MID) received 57mg of BET/kg of body weight, and high dose (HI) received 114mg of BET/kg of body weight. Cows were fed twice daily and BET was top-dressed at each feeding. Cows were milked 2 times/d and milk samples were taken daily for analysis. Milk components, yield, feed intake, and water intake records were taken daily. Rectal temperature and respiration rate were taken 3 times/d at 0600, 1400, and 1800h. Cows were housed in environmentally controlled rooms and were allowed acclimation for 7d at thermoneutral (TN) conditions with a mean temperature-humidity index of 56.6. Cows were then exposed to 7d of TN followed by 7d of HS represented by a temperature-humidity index of 71.5 for 14d. This was followed by a recovery period of 3d at TN. Dietary BET increased milk yield during the TN period. No differences were found between BET and CON in total milk production or milk composition during HS. The increase in water intake during HS was not as great for cows fed BET compared with controls. The cows on CON diets had higher p.m. respiration rate than both MID and HI BET during HS, but lower rectal temperature compared with BET. No difference was found in serum glucose during TN, but cows given HI had elevated glucose levels during HS compared with CON. No differences were found in serum insulin levels between CON and BET but an intake by environment interaction was present with insulin increasing in HI-treated lactating dairy cows during HS. The heat shock response [heat shock protein (HSP) 27 and HSP70] was upregulated in bovine mammary epithelial cells

  5. Explicit, Implicit, and Subjective Rating Measures of Situation Awareness in a Monitoring Task

    Science.gov (United States)

    1991-10-01

    range of the subjects’ weapon (referred to as "envelope sensitivity" and calculated as A’ see Macmillan and Creelman , 1990). In his experiment...1982). Design and analysis: A researchers handbook. Englewood Cliffs, NJ: Prentice-Hall. Macmillan, N. A., and Creelman , C. D. (1990). Response

  6. Nocturnal variations in subcutaneous blood flow rate in lower leg of normal human subjects

    DEFF Research Database (Denmark)

    Sindrup, J H; Kastrup, J; Jørgensen, B

    1991-01-01

    in central and local postural sympathetic vasoconstrictor activity. During sleep, characteristic variations in subcutaneous blood flow were disclosed. The 133Xe washout curve could be divided into three segments with significantly different slopes. Approximately 90 min after the subject went to sleep...

  7. Altered immunological response in mice subjected to stress and exposed to fungal spores

    Science.gov (United States)

    Kurup, Viswanath P.; Choi, Hongyung; Kumar, Anoopa; Murali, Pazhayannur S.; Mishra, S. K.; Pierson, Duane L.

    1992-01-01

    Space flight and related factors such as stress appear to have an adverse effect on astronauts' immune systems. The presence of potentially pathogenic microbes including several genera of fungi reported from spacecraft environment may be a cause of concern in such situations. In order to study the role of such organisms in causing opportunistic or allergic diseases in crewmembers, we have tried to develop an animal model. BALB/c mice were suspended upside down for varying periods of time to induce stress, and their lymphocyte functions were evaluated. These studies indicate that the stress resulted in lowered mitogen induced lymphocyte stimulation as represented by 3H-thymidine uptake. We have also studied the ability of these animals to respond to Aspergillus fumigatus spores. The results of the study clearly demonstrate a definite down-regulation in T-cell proliferation and a higher incidence of infection with A. fumigatus.

  8. Protective Effect of Theaflavin on Erythrocytes Subjected to In Vitro Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Mahejabeen Fatima

    2013-01-01

    Full Text Available Antioxidant and free radical scavenging effect of black tea theaflavins has been shown in many epidemiological studies. In the present work we report the protective mechanism of tea theaflavins on biomarkers of oxidative stress, which are elevated during stress conditions. We hereby report the in vitro effect of theaflavins on erythrocyte malondialdehyde (MDA, intracellular reduced glutathione (GSH, and plasma membrane redox system (PMRS of rats. The effect of theaflavin on PMRS has also been validated through an in silico docking simulation study using Molegro Virtual Docker (MVD. We report that theaflavins show significant protection to erythrocyte against oxidative stress induced by tert-butyl hydroperoxide (t-BHP. The findings suggest a possible protective role of theaflavins as antioxidant.

  9. Heart rate variability biofeedback intervention for reduction of psychological stress during the early postpartum period.

    Science.gov (United States)

    Kudo, Naoko; Shinohara, Hitomi; Kodama, Hideya

    2014-12-01

    This study examined the effectiveness of heart rate variability (HRV) biofeedback intervention for reduction of psychological stress in women in the early postpartum period. On postpartum day 4, 55 healthy subjects received a brief explanation about HRV biofeedback using a portable device. Among them, 25 mothers who agreed to implement HRV biofeedback at home were grouped as the biofeedback group, and other 30 mothers were grouped as the control group. At 1 month postpartum, there was a significant decrease in total Edinburgh Postnatal Depression Scale score (P biofeedback group; this change was brought about mainly by decreases in items related to anxiety or difficulty sleeping. There was also a significant increase in standard deviation of the normal heartbeat interval (P biofeedback group after adjusting for potential covariates. In conclusion, postpartum women who implemented HRV biofeedback after delivery were relatively free from anxiety and complained less of difficulties sleeping at 1 month postpartum. Although the positive effects of HRV biofeedback may be partly attributable to intervention effects, due to its clinical outcome, HRV biofeedback appears to be recommendable for many postpartum women as a feasible health-promoting measure after childbirth.

  10. Changes in salivary microbiota increase volatile sulfur compounds production in healthy male subjects with academic-related chronic stress.

    Directory of Open Access Journals (Sweden)

    Bruno Dias Nani

    Full Text Available To investigate the associations among salivary bacteria, oral emanations of volatile sulfur compounds, and academic-related chronic stress in healthy male subjects.Seventy-eight healthy male undergraduate dental students were classified as stressed or not by evaluation of burnout, a syndrome attributed to academic-related chronic stress. This evaluation was carried out using the Maslach Burnout Inventory-Student Survey questionnaire. Oral emanations of hydrogen sulfide, methyl mercaptan, and dimethyl sulfide were measured using an Oral Chroma™ portable gas chromatograph. The amounts in saliva of total bacteria and seven bacteria associated with halitosis were quantified by qPCR. The in vitro production of H2S by S. moorei and/or F. nucleatum was also measured with the Oral Chroma™ instrument.The stressed students group showed increased oral emanations of hydrogen sulfide and dimethyl sulfide, together with higher salivary Solobacterium moorei levels (p < 0.05, Mann Whitney test. There were moderate positive correlations between the following pairs of variables: Fusobacterium nucleatum and S. moorei; F. nucleatum and hydrogen sulfide; Tannerella forsythia and F. nucleatum; T. forsythia and S. moorei. These correlations only occurred for the stressed group (p < 0.05, Spearman correlation. The in vitro experiment demonstrated that S. moorei increased H2S production by F. nucleatum (p < 0.05, ANOVA and Tukey's test.The increased amount of S. moorei in saliva, and its coexistence with F. nucleatum and T. forsythia, seemed to be responsible for increased oral hydrogen sulfide in the healthy male stressed subjects.

  11. Contact stresses by rounded punch subject to axial and transverse shear

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyung Kyu [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1999-05-01

    Contact shear stresses by rounded punch were evaluated numerically. Numerical program was successfully implemented by using an influence function method. To simulate the physical fretting problem, a closed load path of shear was considered. The influence functions on surface displacements fo both axial and transverse direction were calculated using a triangular shear traction element. Behaviour of the contact surface, such as stick and slip region during the load path was investigated together with compliance change. Irreversibility of the shear stress was shown. The importance and the utilization of the present research were discussed for analyzing the material failure induced by contact such as fretting wear and fatigue.

  12. Contact stresses by rounded punch subject to axial and transverse shear

    International Nuclear Information System (INIS)

    Kim, Hyung Kyu

    1999-01-01

    Contact shear stresses by rounded punch were evaluated numerically. Numerical program was successfully implemented by using an influence function method. To simulate the physical fretting problem, a closed load path of shear was considered. The influence functions on surface displacements fo both axial and transverse direction were calculated using a triangular shear traction element. Behaviour of the contact surface, such as stick and slip region during the load path was investigated together with compliance change. Irreversibility of the shear stress was shown. The importance and the utilization of the present research were discussed for analyzing the material failure induced by contact such as fretting wear and fatigue

  13. Unsteady-state human-body exergy consumption rate and its relation to subjective assessment of dynamic thermal environments

    DEFF Research Database (Denmark)

    Schweiker, Marcel; Kolarik, Jakub; Dovjak, Mateja

    2016-01-01

    of the present study confirmed previously indicated trends that lowest human body exergy consumption rate is associated with thermal sensation close to neutrality. Moreover, higher acceptability was in general associated with lower human body exergy consumption rate. (C) 2016 Elsevier B.V. All rights reserved.......Few examples studied applicability of exergy analysis on human thermal comfort. These examples relate the human-body exergy consumption rate with subjectively obtained thermal sensation votes and had been based on steady-state calculation methods. However, humans are rarely exposed to steady...... between the human-body exergy consumption rate and subjective assessment of thermal environment represented by thermal sensation as well as to extend the investigation towards thermal acceptability votes. Comparison of steady-state and unsteady-state model showed that results from both models were...

  14. Heart Rate and Oxygen Saturation Change Patterns During 6-min Walk Test in Subjects With Chronic Thromboembolic Pulmonary Hypertension.

    Science.gov (United States)

    Inagaki, Takeshi; Terada, Jiro; Yahaba, Misuzu; Kawata, Naoko; Jujo, Takayuki; Nagashima, Kengo; Sakao, Seiichiro; Tanabe, Nobuhiro; Tatsumi, Koichiro

    2017-12-26

    The 6-min walk test (6MWT) is commonly performed to assess functional status in patients with chronic thromboembolic pulmonary hypertension. However, changes in heart rate and oxygen saturation ( S pO 2 ) patterns during 6MWT in patients with chronic thromboembolic pulmonary hypertension remain unclear. Thirty-one subjects with chronic thromboembolic pulmonary hypertension were retrospectively evaluated to examine the relationships between the change in heart rate (Δheart rate), heart rate acceleration time, slope of heart rate acceleration, heart rate recovery during the first minute after 6MWT (HRR1), change in S pO 2 (Δ S pO 2 ), S pO 2 reduction time, and S pO 2 recovery time during 6MWT, and the severity of pulmonary hemodynamics assessed by right heart catheterization and echocardiography. Subjects with severe chronic thromboembolic pulmonary hypertension had significantly longer heart rate acceleration time (144.9 ± 63.9 s vs 96.0 ± 42.5 s, P = .033), lower Δheart rate (47.4 ± 16.9 vs 61.8 ± 13.6 beats, P = .02), and lower HRR1 (13.3 ± 9.0 beats vs 27.1 ± 9.2 beats, P pulmonary hypertension. Subjects with severe chronic thromboembolic pulmonary hypertension also had significantly longer S pO 2 reduction time (178.3 ± 70.3 s vs 134.3 ± 58.4 s, P = .03) and S pO 2 recovery time (107.6 ± 35.3 s vs 69.8 ± 32.7 s, P = .004) than did subjects with mild chronic thromboembolic pulmonary hypertension. Multivariate linear regression analysis showed only mean pulmonary arterial pressure independently was associated with heart rate acceleration time and slope of heart rate acceleration. Heart rate and S pO 2 change patterns during 6MWT is predominantly associated with pulmonary hemodynamics in subjects with chronic thromboembolic pulmonary hypertension. Evaluating heart rate and S pO 2 change patterns during 6MWT may serve a safe and convenient way to follow the change in pulmonary hemodynamics. Copyright © 2017 by Daedalus Enterprises.

  15. Determine variation of poisson ratios and thermal creep stresses and strain rates in an isotropic disc

    Directory of Open Access Journals (Sweden)

    Gupta Nishi

    2016-01-01

    Full Text Available Seth's transition theory is applied to the problem of thermal creep transition stresses and strain rates in a thin rotating disc with shaft having variable density by finite deformation. Neither the yield criterion nor the associated flow rule is assumed here. The results obtained here are applicable to compressible materials. If the additional condition of incompressibility is imposed, then the expression for stresses corresponds to those arising from Tresca yield condition. Thermal effect decreased value of radial stress at the internal surface of the rotating isotropic disc made of compressible material as well as incompressible material and this value of radial stress further much increases with the increase in angular speed. With the introduction of thermal effects, the maximum value of strain rates further increases at the internal surface for compressible materials as compare to incompressible material.

  16. Protein carbonyl: An oxidative stress marker in gingival crevicular fluid in healthy, gingivitis, and chronic periodontitis subjects

    Directory of Open Access Journals (Sweden)

    Avani R Pradeep

    2013-01-01

    Full Text Available Background: A defined role for reactive oxygen species (ROS in the tissue destruction that characterizes periodontitis has been described. Protein carbonyl (PC is the most widely used biomarker for oxidative damage to proteins, and reflects cellular damage induced by multiple forms of ROS. The purpose of this study is to determine the presence of PC in gingival crevicular fluid (GCF in healthy, gingivitis, and chronic periodontitis (CP subjects and to find an association, if any. Materials and Methods: A total number of 75 subjects (38 males and 37 females were selected based on their clinical parameters into three groups: Group 1 (25 healthy subjects, Group 2 (25 gingivitis subjects, and Group 3 (25 CP subjects. GCF samples were collected to estimate the levels of PC. Results: The PC concentration in GCF was highest in subjects with CP as compared to gingivitis and healthy subjects and a significant association was observed between GCF PC levels and all periodontal parameters. Conclusion: There was an increase in PC levels in GCF as the disease process progressed from healthy to gingivitis and CP, suggesting a role for increased oxidative stress in CP.

  17. Sleep electroencephalography and heart rate variability interdependence amongst healthy subjects and insomnia/schizophrenia patients.

    Science.gov (United States)

    Chaparro-Vargas, Ramiro; Schilling, Claudia; Schredl, Michael; Cvetkovic, Dean

    2016-01-01

    The quantification of interdependencies within autonomic nervous system has gained increasing importance to characterise healthy and psychiatric disordered subjects. The present work introduces a biosignal processing approach, suggesting a computational resource to estimate coherent or synchronised interactions as an eventual supportive aid in the diagnosis of primary insomnia and schizophrenia pathologies. By deploying linear, nonlinear and statistical methods upon 25 electroencephalographic and electrocardiographic overnight sleep recordings, the assessment of cross-correlation, wavelet coherence and [Formula: see text]:[Formula: see text] phase synchronisation is focused on tracking discerning features amongst the clinical cohorts. Our results indicate that certain neuronal oscillations interact with cardiac power bands in distinctive ways responding to standardised sleep stages and patient groups, which promotes the hypothesis of subtle functional dynamics between neuronal assembles and (para)sympathetic activity subject to pathophysiological conditions.

  18. Measuring aging rates of mice subjected to caloric restriction and genetic disruption of growth hormone signaling.

    Science.gov (United States)

    Koopman, Jacob J E; van Heemst, Diana; van Bodegom, David; Bonkowski, Michael S; Sun, Liou Y; Bartke, Andrzej

    2016-03-01

    Caloric restriction and genetic disruption of growth hormone signaling have been shown to counteract aging in mice. The effects of these interventions on aging are examined through age-dependent survival or through the increase in age-dependent mortality rates on a logarithmic scale fitted to the Gompertz model. However, these methods have limitations that impede a fully comprehensive disclosure of these effects. Here we examine the effects of these interventions on murine aging through the increase in age-dependent mortality rates on a linear scale without fitting them to a model like the Gompertz model. Whereas these interventions negligibly and non-consistently affected the aging rates when examined through the age-dependent mortality rates on a logarithmic scale, they caused the aging rates to increase at higher ages and to higher levels when examined through the age-dependent mortality rates on a linear scale. These results add to the debate whether these interventions postpone or slow aging and to the understanding of the mechanisms by which they affect aging. Since different methods yield different results, it is worthwhile to compare their results in future research to obtain further insights into the effects of dietary, genetic, and other interventions on the aging of mice and other species.

  19. Reduced Synapse and Axon Numbers in the Prefrontal Cortex of Rats Subjected to a Chronic Stress Model for Depression

    Science.gov (United States)

    Csabai, Dávid; Wiborg, Ove; Czéh, Boldizsár

    2018-01-01

    Stressful experiences can induce structural changes in neurons of the limbic system. These cellular changes contribute to the development of stress-induced psychopathologies like depressive disorders. In the prefrontal cortex of chronically stressed animals, reduced dendritic length and spine loss have been reported. This loss of dendritic material should consequently result in synapse loss as well, because of the reduced dendritic surface. But so far, no one studied synapse numbers in the prefrontal cortex of chronically stressed animals. Here, we examined synaptic contacts in rats subjected to an animal model for depression, where animals are exposed to a chronic stress protocol. Our hypothesis was that long term stress should reduce the number of axo-spinous synapses in the medial prefrontal cortex. Adult male rats were exposed to daily stress for 9 weeks and afterward we did a post mortem quantitative electron microscopic analysis to quantify the number and morphology of synapses in the infralimbic cortex. We analyzed asymmetric (Type I) and symmetric (Type II) synapses in all cortical layers in control and stressed rats. We also quantified axon numbers and measured the volume of the infralimbic cortex. In our systematic unbiased analysis, we examined 21,000 axon terminals in total. We found the following numbers in the infralimbic cortex of control rats: 1.15 × 109 asymmetric synapses, 1.06 × 108 symmetric synapses and 1.00 × 108 myelinated axons. The density of asymmetric synapses was 5.5/μm3 and the density of symmetric synapses was 0.5/μm3. Average synapse membrane length was 207 nm and the average axon terminal membrane length was 489 nm. Stress reduced the number of synapses and myelinated axons in the deeper cortical layers, while synapse membrane lengths were increased. These stress-induced ultrastructural changes indicate that neurons of the infralimbic cortex have reduced cortical network connectivity. Such reduced network connectivity is likely

  20. Reduced Synapse and Axon Numbers in the Prefrontal Cortex of Rats Subjected to a Chronic Stress Model for Depression

    Directory of Open Access Journals (Sweden)

    Dávid Csabai

    2018-01-01

    Full Text Available Stressful experiences can induce structural changes in neurons of the limbic system. These cellular changes contribute to the development of stress-induced psychopathologies like depressive disorders. In the prefrontal cortex of chronically stressed animals, reduced dendritic length and spine loss have been reported. This loss of dendritic material should consequently result in synapse loss as well, because of the reduced dendritic surface. But so far, no one studied synapse numbers in the prefrontal cortex of chronically stressed animals. Here, we examined synaptic contacts in rats subjected to an animal model for depression, where animals are exposed to a chronic stress protocol. Our hypothesis was that long term stress should reduce the number of axo-spinous synapses in the medial prefrontal cortex. Adult male rats were exposed to daily stress for 9 weeks and afterward we did a post mortem quantitative electron microscopic analysis to quantify the number and morphology of synapses in the infralimbic cortex. We analyzed asymmetric (Type I and symmetric (Type II synapses in all cortical layers in control and stressed rats. We also quantified axon numbers and measured the volume of the infralimbic cortex. In our systematic unbiased analysis, we examined 21,000 axon terminals in total. We found the following numbers in the infralimbic cortex of control rats: 1.15 × 109 asymmetric synapses, 1.06 × 108 symmetric synapses and 1.00 × 108 myelinated axons. The density of asymmetric synapses was 5.5/μm3 and the density of symmetric synapses was 0.5/μm3. Average synapse membrane length was 207 nm and the average axon terminal membrane length was 489 nm. Stress reduced the number of synapses and myelinated axons in the deeper cortical layers, while synapse membrane lengths were increased. These stress-induced ultrastructural changes indicate that neurons of the infralimbic cortex have reduced cortical network connectivity. Such reduced network

  1. Temperature and strain-rate dependence of the flow stress of ultrapure tantalum single crystals

    International Nuclear Information System (INIS)

    Werner, M.

    1987-01-01

    Measurements of the temperature dependence of the cyclic flow stress of ultrapure tantalum single crystals (RRR >∼ 14000) are extended to lower temperatures. After cyclic deformation well into saturation at 400 K, the temperature dependence of the flow stress is measured between 80 and 450 K at five different plastic resolved shear-strain rates, ε pl , in the range 2 x 10 -5 to 6 x 10 -3 s -1 . Below a critical temperature T k the flow stress is dominantly controlled by the mobility of screw dislocations. A recent theory of Seeger describes the 'thermal' component, σ*, of the flow stress (resolved shear stress) in the temperature and stress regime where the strain rate is determined by the formation and migration of kink pairs. The analytical expressions are valid in well-defined ranges of stress and temperature. The evaluation of the experimental data yields a value for the formation enthalpy of two isolated kinks 2H k = 0.98 eV. From the low-stress (σ* k = 2.0 x 10 -6 m 2 s -1 . The product of the density of mobile screw dislocations and the distance between insurmountable obstacles is found to be 2 x 10 -5 m -1 . The stress dependence of the kink-pair formation enthalpy H kp follows the theoretically predicted curve in the elastic-interaction stress regime. At the transition to the line-tension approximation (near σ* ∼ 80 MPa) the activation volume increases rather abruptly. Moreover, the quantitative analysis involves kinks other than those of minimum height. The most likely candidates are kinks on {211} planes. (author)

  2. Simulation of Stress-Strain behavior for one-dimensional aluminum samples subjected to high temperature

    DEFF Research Database (Denmark)

    Bellini, Anna; Thorborg, Jesper; Hattel, Jesper

    2004-01-01

    , financed by the EU in frame work 6 and born in collaboration with the automobile and foundry industries, to fill the mentioned gap. Through a systematic analysis of experimental tests, this study aims to develop a powerful predicting tool capable of capturing stress relaxation effects through an adequate...

  3. Measuring Stress-Reducing Effects of Virtual Training Based on Subjective Response

    NARCIS (Netherlands)

    Bosse, T.; Gerritsen, C.; de Man, J.; Treur, J.

    2012-01-01

    Training to cope with negative emotions or stress is important for professionals with a high pressure job, such as police officers and military personnel. The work reported in this paper is part of a project that aims to develop a Virtual Reality based training environment for such professionals. As

  4. Gender Differences in the Psychosomatic Reactions of Students Subjected to Examination Stress

    Science.gov (United States)

    Kosmala-Anderson, Joanna; Wallace, Louise M.

    2007-01-01

    Introduction: The study investigated pre-examination anxiety and emotional control strategies as possible mediators of gender differences in self reported intensity and type of psychosomatic reactions to examination stress. Method: Sample comprised 150 male and 150 female high school senior students and university students who voluntarily…

  5. Sex Differences in Cardiovascular and Subjective Stress Reactions: Prospective Evidence in a Realistic Military Setting

    Science.gov (United States)

    2014-01-01

    this study require comment. Importantly, we did not control for menstrual phase or oral contraceptive use. Reproductive hormones may be implicated in...differences in emotional and physiological responses to the Trier Social Stress Test. J Behav Ther Exp Psychiatry 39:87–98. Kirschbaum C, Pirke KM

  6. Age Identity in Context: Stress and the Subjective Side of Aging

    Science.gov (United States)

    Schafer, Markus H.; Shippee, Tetyana Pylypiv

    2010-01-01

    The passage of time is fundamentally experienced through people's interaction with their social worlds. Life-course scholars acknowledge the multiple aspects of time-based experience but have given little attention to age identity in a dynamic context. Drawing from a stress-process model, we expected that turbulence within people's family…

  7. MOTOR UNIT FIRING RATES DURING SPASMS IN THENAR MUSCLES OF SPINAL CORD INJURED SUBJECTS

    Directory of Open Access Journals (Sweden)

    Inge eZijdewind

    2014-11-01

    Full Text Available Abstract Involuntary contractions of paralyzed muscles (spasms commonly disrupt daily activities and rehabilitation after human spinal cord injury. Our aim was to examine the recruitment, firing rate modulation, and derecruitment of motor units that underlie spasms of thenar muscles after cervical spinal cord injury. Intramuscular electromyographic activity (EMG, surface EMG, and force were recorded during thenar muscle spasms that occurred spontaneously or that were triggered by movement of a shoulder or leg. Most spasms were submaximal (mean: 39%, SD: 33 of the force evoked by median nerve stimulation at 50 Hz with strong relationships between EMG and force (R2>0.69. Unit recruitment occurred over a wide force range (0.2-103% of 50 Hz force. Significant unit rate modulation occurred during spasms (frequency at 25% maximal force: 8.8 Hz, 3.3 SD; at maximal force: 16.1 Hz, 4.1 SD. Mean recruitment frequency (7.1 Hz, 3.2 SD was significantly higher than derecruitment frequency (5.4 Hz, 2.4 SD. Coactive unit pairs that fired for more than 4 s showed high (R2>0.7, n=4 or low (R2:0.3-0.7, n=12 rate-rate correlations, and derecruitment reversals (21 pairs, 29%. Later recruited units had higher or lower maximal firing rates than lower threshold units. These discrepant data show that coactive motoneurons are driven by both common inputs and by synaptic inputs from different sources during muscle spasms. Further, thenar motoneurons can still fire at high rates in response to various peripheral inputs after spinal cord injury, supporting the idea that low maximal voluntary firing rates and forces in thenar muscles result from reduced descending drive.

  8. Assessment of salivary calcium, phosphate, magnesium, pH, and flow rate in healthy subjects, periodontitis, and dental caries.

    Science.gov (United States)

    Rajesh, K S; Zareena; Hegde, Shashikanth; Arun Kumar, M S

    2015-01-01

    This study was conducted to estimate and compare inorganic salivary calcium, phosphate, magnesium, salivary flow rate, and pH of unstimulated saliva and oral hygiene status of healthy subjects, subjects with periodontitis and dental caries, and to correlate salivary calcium level with number of intact teeth. The study population consisted of 48 systemically healthy subjects in the age group of 18-55 years, which was further divided into three groups: healthy, periodontitis, and dental caries. Oral hygiene index-simplified, probing pocket depth, clinical attachment level, the number of intact teeth, and active carious lesions were recorded. Estimation of inorganic salivary calcium, phosphate, and magnesium was performed spectrophotometrically using Vitros 5.1 FS. Statistical analysis was performed using the one-way analysis of variance test at 5% significance level. There was a statistically significant increase in inorganic salivary calcium, phosphate, pH, flow rate, and poor oral hygiene status in periodontitis group compared to dental caries and healthy group. Subjects with increased inorganic salivary calcium, phosphate, pH, flow rate, and poor oral hygiene are at a higher risk of developing periodontitis. Since there is increased remineralization potential, these subjects have more number of intact teeth compared to the dental caries group.

  9. Assessment of salivary calcium, phosphate, magnesium, pH, and flow rate in healthy subjects, periodontitis, and dental caries

    Directory of Open Access Journals (Sweden)

    K S Rajesh

    2015-01-01

    Full Text Available Aim: This study was conducted to estimate and compare inorganic salivary calcium, phosphate, magnesium, salivary flow rate, and pH of unstimulated saliva and oral hygiene status of healthy subjects, subjects with periodontitis and dental caries, and to correlate salivary calcium level with number of intact teeth. Materials and Methods: The study population consisted of 48 systemically healthy subjects in the age group of 18-55 years, which was further divided into three groups: healthy, periodontitis, and dental caries. Oral hygiene index-simplified, probing pocket depth, clinical attachment level, the number of intact teeth, and active carious lesions were recorded. Estimation of inorganic salivary calcium, phosphate, and magnesium was performed spectrophotometrically using Vitros 5.1 FS. Statistical analysis was performed using the one-way analysis of variance test at 5% significance level. Results: There was a statistically significant increase in inorganic salivary calcium, phosphate, pH, flow rate, and poor oral hygiene status in periodontitis group compared to dental caries and healthy group. Conclusion: Subjects with increased inorganic salivary calcium, phosphate, pH, flow rate, and poor oral hygiene are at a higher risk of developing periodontitis. Since there is increased remineralization potential, these subjects have more number of intact teeth compared to the dental caries group.

  10. Slow strain rate stress corrosion cracking under multiaxial deformation conditions: technique and application to admiralty brass

    International Nuclear Information System (INIS)

    Blanchard, W.K.; Heldt, L.A.; Koss, D.

    1984-01-01

    A set of straightforward experimental techniques are described for the examination of slow strain rate stress corrosion cracking (SCC) of sheet deforming under nearly all multiaxial deformation conditions which result in sheet thinning. Based on local fracture strain as a failure criterion, the results contrast stress corrosion susceptibility in uniaxial tension with those in both plane strain and balanced biaxial tension. These results indicate that the loss of ductility of the brass increases as the stress state changes from uniaxial toward balanced biaxial tension

  11. Oxidative stress augments toll-like receptor 8 mediated neutrophilic responses in healthy subjects

    Directory of Open Access Journals (Sweden)

    Matsunaga Kazuto

    2009-06-01

    Full Text Available Abstract Background Excessive oxidative stress has been reported to be generated in inflamed tissues and contribute to the pathogenesis of inflammatory lung diseases, exacerbations of which induced by viral infections are associated with toll-like receptor (TLR activation. Among these receptors, TLR8 has been reported as a key receptor that recognizes single-strand RNA virus. However, it remains unknown whether TLR8 signaling is potentiated by oxidative stress. The aim of this study is to examine whether oxidative stress modulates TLR8 signaling in vitro. Methods Human peripheral blood neutrophils were obtained from healthy non-smokers and stimulated with TLR 7/8 agonist imidazoquinoline resiquimod (R848 in the presence or absence of hydrogen peroxide (H2O2. Neutrophilic responses including cytokine release, superoxide production and chemotaxis were examined, and the signal transduction was also analyzed. Results Activation of TLR8, but not TLR7, augmented IL-8 release. The R848-augmented IL-8 release was significantly potentiated by pretreatment with H2O2 (p L-cysteine reversed this potentiation. The combination of H2O2 and R848 significantly potentiated NF-kB phosphorylation and IkBα degradation. The H2O2-potentiated IL-8 release was suppressed by MG-132, a proteosome inhibitor, and by dexamethasone. The expressions of TLR8, myeloid differentiation primary response gene 88 (MyD88, and tumor necrosis factor receptor-associated factor 6 (TRAF6 were not affected by H2O2. Conclusion TLR8-mediated neutrophilic responses were markedly potentiated by oxidative stress, and the potentiation was mediated by enhanced NF-kB activation. These results suggest that oxidative stress might potentiate the neutrophilic inflammation during viral infection.

  12. Emotional intelligence, life satisfaction and subjective happiness in female student health professionals: the mediating effect of perceived stress.

    Science.gov (United States)

    Ruiz-Aranda, D; Extremera, N; Pineda-Galán, C

    2014-03-01

    The objective of the present study was to extend previous findings by examining the relationship between emotional intelligence (EI) and well-being indicators (life satisfaction and happiness) in a 12-week follow-up study. In addition, we examined the influence of perceived stress on the relationship between EI and well-being. Female students from the School of Health Sciences (n = 264) completed an ability measure of emotional intelligence. After 12 weeks, participants completed the Perceived Stress Scale, Satisfaction with Life Scale and Subjective Happiness Scale. Participants with higher EI reported less perceived stress and higher levels of life satisfaction and happiness. The results of this study suggest that perceived stress mediates the relationship between EI and well-being indicators, specifically life satisfaction and happiness. These findings suggest an underlying process by which high emotional intelligence may increase well-being in female students in nursing and allied health sciences by reducing the experience of stress. The implications of these findings for future research and for working with health professions to improve well-being outcomes are discussed. © 2013 John Wiley & Sons Ltd.

  13. The Role of Personality and Subjective Exposure Experiences in Posttraumatic Stress Disorder and Depression Symptoms among Children Following Wenchuan Earthquake.

    Science.gov (United States)

    Chen, Xiacan; Xu, Jiajun; Li, Bin; Li, Na; Guo, Wanjun; Ran, Mao-Sheng; Zhang, Jun; Yang, Yanchun; Hu, Junmei

    2017-12-08

    This study aims to investigate the role of personality traits and subjective exposure experiences in posttraumatic stress disorder and depression symptoms. In Qingchuan, 21,652 children aged 7 to 15 years were assessed using face-to-face interviews one year after the Wenchuan earthquake in China. The Junior Eysenck Personality Questionnaire, a modified earthquake exposure scale, the UCLA Posttraumatic Stress Disorder Reaction Index (adolescent), and the Adolescent Depression Inventory were used to assess personality characteristics, trauma experiences, posttraumatic stress disorder and depression symptoms, respectively. The measurement was completed with 20,749 children. After adjusting for other factors by multinomial logistic regression analysis, neuroticism, having felt unable to escape from the disaster and having been trapped for a longer time were risk factors of posttraumatic stress disorder and depression symptoms. Socialization was a protective factor of them. Having felt extreme panic or fear was a risk factor of posttraumatic stress disorder symptoms. For depression symptoms, introversion and psychoticism were risk factors, and extraversion was a protective factor. This study was conducted with the largest representative sample of child survivors of a natural, devastating disaster in a developing country. These results could be useful for planning psychological intervention strategies for children and for influencing further research.

  14. Characterization of a New Fully Recycled Carbon Fiber Reinforced Composite Subjected to High Strain Rate Tension

    Science.gov (United States)

    Meftah, H.; Tamboura, S.; Fitoussi, J.; BenDaly, H.; Tcharkhtchi, A.

    2018-06-01

    The aim of this study is the complete physicochemical characterization and strain rate effect multi-scale analysis of a new fully recycled carbon fiber reinforced composites for automotive crash application. Two composites made of 20% wt short recycled carbon fibers (CF) are obtained by injection molding. The morphology and the degree of dispersion of CF in the matrixes were examined using a new ultrasonic method and SEM. High strain tensile behavior up to 100 s-1 is investigated. In order to avoid perturbation due to inertial effect and wave propagation, the specimen geometry was optimized. The elastic properties appear to be insensitive to the strain rate. However, a high strain rate effect on the local visco-plasticity of the matrix and fiber/matrix interface visco-damageable behavior is emphasized. The predominant damage mechanisms evolve from generalized matrix local ductility at low strain rate regime to fiber/matrix interface debonding and fibers pull-out at high strain rate regime.

  15. Two Back Stress Hardening Models in Rate Independent Rigid Plastic Deformation

    Science.gov (United States)

    Yun, Su-Jin

    In the present work, the constitutive relations based on the combination of two back stresses are developed using the Armstrong-Frederick, Phillips and Ziegler’s type hardening rules. Various evolutions of the kinematic hardening parameter can be obtained by means of a simple combination of back stress rate using the rule of mixtures. Thus, a wide range of plastic deformation behavior can be depicted depending on the dominant back stress evolution. The ultimate back stress is also determined for the present combined kinematic hardening models. Since a kinematic hardening rule is assumed in the finite deformation regime, the stress rate is co-rotated with respect to the spin of substructure obtained by incorporating the plastic spin concept. A comparison of the various co-rotational rates is also included. Assuming rigid plasticity, the continuum body consists of the elastic deformation zone and the plastic deformation zone to form a hybrid finite element formulation. Then, the plastic deformation behavior is investigated under various loading conditions with an assumption of the J2 deformation theory. The plastic deformation localization turns out to be strongly dependent on the description of back stress evolution and its associated hardening parameters. The analysis for the shear deformation with fixed boundaries is carried out to examine the deformation localization behavior and the evolution of state variables.

  16. Reliability and Validity of the Clinical Dementia Rating for Community-Living Elderly Subjects without an Informant

    Directory of Open Access Journals (Sweden)

    Ma Shwe Zin Nyunt

    2013-10-01

    Full Text Available Background: The Clinical Dementia Rating (CDR scale is widely used to assess cognitive impairment in Alzheimer's disease. It requires collateral information from a reliable informant who is not available in many instances. We adapted the original CDR scale for use with elderly subjects without an informant (CDR-NI and evaluated its reliability and validity for assessing mild cognitive impairment (MCI and dementia among community-dwelling elderly subjects. Method: At two consecutive visits 1 week apart, nurses trained in CDR assessment interviewed, observed and rated cognitive and functional performance according to a protocol in 90 elderly subjects with suboptimal cognitive performance [Mini-Mental State Examination (MMSE Results: The CDR-NI scores (0, 0.5, 1 showed good internal consistency (Crohnbach's a 0.83-0.84, inter-rater reliability (κ 0.77-1.00 for six domains and 0.95 for global rating and test-retest reliability (κ 0.75-1.00 for six domains and 0.80 for global rating, good agreement (κ 0.79 with the clinical assessment status of MCI (n = 37 and dementia (n = 4 and significant differences in the mean scores for MMSE, MOCA and Instrumental Activities of Daily Living (ANOVA global p Conclusion: Owing to the protocol of the interviews, assessments and structured observations gathered during the two visits, CDR-NI provides valid and reliable assessment of MCI and dementia in community-living elderly subjects without an informant.

  17. Reliability and Validity of the Clinical Dementia Rating for Community-Living Elderly Subjects without an Informant.

    Science.gov (United States)

    Nyunt, Ma Shwe Zin; Chong, Mei Sian; Lim, Wee Shiong; Lee, Tih Shih; Yap, Philip; Ng, Tze Pin

    2013-01-01

    The Clinical Dementia Rating (CDR) scale is widely used to assess cognitive impairment in Alzheimer's disease. It requires collateral information from a reliable informant who is not available in many instances. We adapted the original CDR scale for use with elderly subjects without an informant (CDR-NI) and evaluated its reliability and validity for assessing mild cognitive impairment (MCI) and dementia among community-dwelling elderly subjects. At two consecutive visits 1 week apart, nurses trained in CDR assessment interviewed, observed and rated cognitive and functional performance according to a protocol in 90 elderly subjects with suboptimal cognitive performance [Mini-Mental State Examination (MMSE) reliability (κ 0.77-1.00 for six domains and 0.95 for global rating) and test-retest reliability (κ 0.75-1.00 for six domains and 0.80 for global rating), good agreement (κ 0.79) with the clinical assessment status of MCI (n = 37) and dementia (n = 4) and significant differences in the mean scores for MMSE, MOCA and Instrumental Activities of Daily Living (ANOVA global p reliable assessment of MCI and dementia in community-living elderly subjects without an informant.

  18. Measuring Cognitive Load during Simulation-Based Psychomotor Skills Training: Sensitivity of Secondary-Task Performance and Subjective Ratings

    Science.gov (United States)

    Haji, Faizal A.; Khan, Rabia; Regehr, Glenn; Drake, James; de Ribaupierre, Sandrine; Dubrowski, Adam

    2015-01-01

    As interest in applying cognitive load theory (CLT) to the study and design of pedagogic and technological approaches in healthcare simulation grows, suitable measures of cognitive load (CL) are needed. Here, we report a two-phased study investigating the sensitivity of subjective ratings of mental effort (SRME) and secondary-task performance…

  19. Stressed out or subjective acquisition of competence – how do veterinary students see their curative work placement?

    Science.gov (United States)

    Dilly, Marc; Tipold, Andrea; Geuenich, Katja

    2016-01-01

    Veterinary studies in Germany are regulated by the Veterinary Certification Act (TAppV). The practical part of the education consists of 1,170 hours, whereby up to 850 hours can be spent on the curative work placement. A curative work placement can result in physical and psychological stress in the sense of a professional overload. It is the aim of this study to find out in what areas and to what extent competence is acquired and psychological stress exists in students during their work placement. Veterinary students (n=142) from all German education institutes participated in a voluntary online-study based on Burnout Screening Scales (BOSS) as well as a questionnaire regarding the acquisition of competence and excessive stress during the work placement (FKÜP). The distribution of values for work placement related stress show that such work placement related stress is generally slightly increased (T=60) and lies above that of occupational stresses within the normal population. Work placement related physical complaints also show a significant slight increase (T=61). A value (T=42) within the normal range was determined for the resource values. Few of the students questioned considered themselves to be excessively stressed in favour of a high subjective acquisition of competences. The largest increase regarding the acquisition of competence was noted for the areas of animal handling/restraint and application and injection techniques. In the sense of a perceived excessive demand regarding practical capabilities the areas of emergency management, surgery and medication dispensation were mentioned. With regard to the load structure and the acquisition of competence by veterinary students during their work placement, more support of the individual and a balancing of teaching/learning goals would be desirable and represents a promising approach. PMID:26958657

  20. Subjective social status, self-rated health and tobacco smoking: Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

    Science.gov (United States)

    Camelo, Lidyane do V; Giatti, Luana; Barreto, Sandhi M

    2014-11-01

    Using baseline data from ELSA-Brasil (N = 15,105), we investigated whether subjective social status, measured using three 10-rung "ladders," is associated with self-rated health and smoking, independently of objective indicators of social position and depression symptoms. Additionally, we explored whether the magnitude of these associations varies according to the reference group. Subjective social status was independently associated with poor self-rated health and weakly associated with former smoking. The references used for social comparison did not change these associations significantly. Subjective social status, education, and income represent distinct aspects of social inequities, and the impact of each of these indicators on health is different. © The Author(s) 2013.

  1. Relationship between obesity, negative affect and basal heart rate in predicting heart rate reactivity to psychological stress among adolescents.

    Science.gov (United States)

    Park, Andres E; Huynh, Pauline; Schell, Anne M; Baker, Laura A

    2015-08-01

    Reduced cardiovascular responses to psychological stressors have been found to be associated with both obesity and negative affect in adults, but have been less well studied in children and adolescent populations. These findings have most often been interpreted as reflecting reduced sympathetic nervous system response, perhaps associated with heightened baseline sympathetic activation among the obese and those manifesting negative affect. However, obesity and negative affect may themselves be correlated, raising the question of whether they both independently affect cardiovascular reactivity. The present study thus examined the separate effects of obesity and negative affect on both cardiovascular and skin conductance responses to stress (e.g., during a serial subtraction math task) in adolescents, while controlling for baseline levels of autonomic activity during rest. Both obesity and negative affect had independent and negative associations with cardiovascular reactivity, such that reduced stress responses were apparent for obese adolescents and those with high levels of negative affect. In contrast, neither obesity nor negative affect was related to skin conductance responses to stress, implicating specifically noradrenergic mechanisms rather than sympathetic mechanisms generally as being deficient. Moreover, baseline heart rate was unrelated to obesity in this sample, which suggests that heightened baseline of sympathetic activity is not necessary for the reduced cardiovascular reactivity to stress. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Metabolic effects of dark chocolate consumption on energy, gut microbiota, and stress-related metabolism in free-living subjects.

    Science.gov (United States)

    Martin, Francois-Pierre J; Rezzi, Serge; Peré-Trepat, Emma; Kamlage, Beate; Collino, Sebastiano; Leibold, Edgar; Kastler, Jürgen; Rein, Dietrich; Fay, Laurent B; Kochhar, Sunil

    2009-12-01

    Dietary preferences influence basal human metabolism and gut microbiome activity that in turn may have long-term health consequences. The present study reports the metabolic responses of free living subjects to a daily consumption of 40 g of dark chocolate for up to 14 days. A clinical trial was performed on a population of 30 human subjects, who were classified in low and high anxiety traits using validated psychological questionnaires. Biological fluids (urine and blood plasma) were collected during 3 test days at the beginning, midtime and at the end of a 2 week study. NMR and MS-based metabonomics were employed to study global changes in metabolism due to the chocolate consumption. Human subjects with higher anxiety trait showed a distinct metabolic profile indicative of a different energy homeostasis (lactate, citrate, succinate, trans-aconitate, urea, proline), hormonal metabolism (adrenaline, DOPA, 3-methoxy-tyrosine) and gut microbial activity (methylamines, p-cresol sulfate, hippurate). Dark chocolate reduced the urinary excretion of the stress hormone cortisol and catecholamines and partially normalized stress-related differences in energy metabolism (glycine, citrate, trans-aconitate, proline, beta-alanine) and gut microbial activities (hippurate and p-cresol sulfate). The study provides strong evidence that a daily consumption of 40 g of dark chocolate during a period of 2 weeks is sufficient to modify the metabolism of free living and healthy human subjects, as per variation of both host and gut microbial metabolism.

  3. Heart Rate Variability Frequency Domain Alterations among Healthy Nurses Exposed to Prolonged Work Stress.

    Science.gov (United States)

    Borchini, Rossana; Veronesi, Giovanni; Bonzini, Matteo; Gianfagna, Francesco; Dashi, Oriana; Ferrario, Marco Mario

    2018-01-11

    The deregulation of the autonomic nervous system assessed through the heart rate variability (HRV) analysis is a promising pathway linking work stress and cardiovascular diseases. We aim to investigate the associations between HRV High Frequency (HF) and Low Frequency (LF) powers and work stress in a sample of 36 healthy nurses. Perceived work stress was assessed twice one year apart, using the Job Content and Effort Reward Imbalance questionnaires. This allows to classify nurses in three exposure groups: "prolonged high stress" (PHS), "recent high stress" (RHS) and "stable low stress" (SLS). A 24-h ECG monitoring was later performed during a working day (WD) and a subsequent resting day (RD). Statistically significantly lower ( p working periods. In the subsequent resting periods, HF means showed increases over time in the RHS (beta = +0.41, p working and resting periods. Our study evidences that both prolonged and recent perceived high work stress were associated with a reduction of HF and LF powers during work. In addition, prolonged stress was associated with a lack of recovery during not-working and resting periods.

  4. Flow rate dependency of critical wall shear stress in a radial-flow cell

    DEFF Research Database (Denmark)

    Detry, J.G.; Jensen, Bo Boye Busk; Sindic, M.

    2009-01-01

    In the present work, a radial-flow cell was used to study the removal of starch particle aggregates from several solid substrates (glass, stainless steel, polystyrene and PTFE) in order to determine the critical wall shear stress value for each case. The particle aggregates were formed by aspersion...... of a water or ethanol suspension of starch granules on the surfaces. Depending on the substrate and on the suspending liquid, the aggregates differed in size and shape. Aggregate removal was studied at two flow rates. At the lower flow rate (Re-inlet = 955), the values of critical wall shear stress...... for the different surfaces suggested that capillary forces were, for all of them, playing an important role in aggregate adhesion since aqueous based aggregates were always more difficult to remove. At the higher flow rate (Re-inlet = 2016) the critical wall shear stress increased as a result of the change...

  5. Subjective rating and objective evaluation of the acoustic and indoor climate conditions in video conferencing rooms

    DEFF Research Database (Denmark)

    Hauervig-Jørgensen, Charlotte; Jeong, Cheol-Ho; Toftum, Jørn

    2017-01-01

    Today, face-to-face meetings are frequently replaced by video conferences in order to reduce costs and carbon footprint related to travels and to increase the company efficiency. Yet, complaints about the difficulty of understanding the speech of the participants in both rooms of the video...... conference occur. The aim of this study is to find out the main causes of difficulties in speech communication. Correlation studies between subjective perceptions were conducted through questionnaires and objective acoustic and indoor climate parameters related to video conferencing. Based on four single...

  6. Arbuscular mycorrhizal fungi modify nutrient allocation and composition in wheat (Triticum aestivum L.) subjected to heat-stress

    DEFF Research Database (Denmark)

    Cabral, Carmina; Ravnskov, Sabine; Tringovska, Ivanka

    2016-01-01

    - and micronutrient concentrations in aboveground biomass; evaluation of AM fungal structures in roots and assessment of light-use efficiency of plants. Results AM increased grain number in wheat under heat-stress, and altered nutrient allocation and tiller nutrient composition. Heat increased number of arbuscules...... in wheat root, whereas number of vesicles and total colonization were unaffected. Heat increased photosystem II yield and the electron transfer rate, whereas non-photochemical quenching decreased during the first 2 days of heat-stress. Conclusions Nutrient allocation and –composition in wheat grown under...

  7. Self-rated health status and subjective health complaints associated with health-promoting lifestyles among urban Chinese women: a cross-sectional study.

    Science.gov (United States)

    Cheng, Jingru; Wang, Tian; Li, Fei; Xiao, Ya; Bi, Jianlu; Chen, Jieyu; Sun, Xiaomin; Wu, Liuguo; Wu, Shengwei; Liu, Yanyan; Luo, Ren; Zhao, Xiaoshan

    2015-01-01

    This study aimed to investigate whether self-rated health status (SRH) and subjective health complaints (SHC) of urban Chinese women are associated with their health-promoting lifestyles (HPL). We conducted a cross-sectional study on 8142 eligible Chinese participants between 2012 and 2013. Demographic and SHC data were collected. Each subject completed the SRH questionnaire and the Chinese version of the Health-Promoting Lifestyle Profile-II (HPLP-II). Correlation and binary regression analyses were performed to examine the associations of SRH and SHC with HPL. Both SRH and HPL of urban Chinese women were moderate. The most common complaints were fatigue (1972, 24.2%), eye discomfort (1571, 19.3%), and insomnia (1542, 18.9%). Teachers, highly educated subjects and elderly women had lower SRH scores, while college students and married women had better HPL. All items of HPLP-II were positively correlated with SRH (r = 0.127-0.533, P = 0.000) and negatively correlated with SHC to a significant extent (odds ratio [OR] = 1.40-11.37). Aspects of HPL, particularly stress management and spiritual growth, are associated with higher SRH and lower SHC ratings among urban Chinese women. Physical activity and health responsibility are additionally related to reduced fatigue and nervousness. We believe that these findings will be instrumental in encouraging researchers and urban women to adopt better health-promoting lifestyles with different priorities in their daily lives.

  8. Self-rated health status and subjective health complaints associated with health-promoting lifestyles among urban Chinese women: a cross-sectional study.

    Directory of Open Access Journals (Sweden)

    Jingru Cheng

    Full Text Available This study aimed to investigate whether self-rated health status (SRH and subjective health complaints (SHC of urban Chinese women are associated with their health-promoting lifestyles (HPL.We conducted a cross-sectional study on 8142 eligible Chinese participants between 2012 and 2013. Demographic and SHC data were collected. Each subject completed the SRH questionnaire and the Chinese version of the Health-Promoting Lifestyle Profile-II (HPLP-II. Correlation and binary regression analyses were performed to examine the associations of SRH and SHC with HPL.Both SRH and HPL of urban Chinese women were moderate. The most common complaints were fatigue (1972, 24.2%, eye discomfort (1571, 19.3%, and insomnia (1542, 18.9%. Teachers, highly educated subjects and elderly women had lower SRH scores, while college students and married women had better HPL. All items of HPLP-II were positively correlated with SRH (r = 0.127-0.533, P = 0.000 and negatively correlated with SHC to a significant extent (odds ratio [OR] = 1.40-11.37.Aspects of HPL, particularly stress management and spiritual growth, are associated with higher SRH and lower SHC ratings among urban Chinese women. Physical activity and health responsibility are additionally related to reduced fatigue and nervousness. We believe that these findings will be instrumental in encouraging researchers and urban women to adopt better health-promoting lifestyles with different priorities in their daily lives.

  9. Motor unit firing rates during spasms in thenar muscles of spinal cord injured subjects

    NARCIS (Netherlands)

    Zijdewind, Inge; Bakels, Robert; Thomas, Christine K.

    2014-01-01

    Involuntary contractions of paralyzed muscles (spasms) commonly disrupt daily activities and rehabilitation after human spinal cord injury (SCI). Our aim was to examine the recruitment, firing rate modulation, and derecruitment of motor units that underlie spasms of thenar muscles after cervical

  10. Changes of Aldosterone Secretion Rate Following Furosemide Administration in Normotensive Subjects with High Sodium Intake

    International Nuclear Information System (INIS)

    Sung, Ho Kyung; Ryu, Yong Wun; Koh, Joo Hwan

    1976-01-01

    Marked augmentation of urinary aldosterone excretion following furosemide administration was observed in previous experiment. In this study, author measured the changes of aldosterone secretion after furosemide administration in normotensive young volunteers with high sodium intake. After intravenous injection of 1.2- 3 H-aldosterone, urine samples were collected in course of time until 24 hours after the injection. Furosemide administration was done at 30 minutes prior to aldosterone injection. Specific activities of 3H-aldosterone during and after diuresis were measured and aldosterone secretion rates were calculated dividing the doses by specific activities. Results were as followed. 1) Furosemide resulted in a marked increase in urinary aldosterone excretion. 2) Furosemide lead to an increase in both sodium and potassium excretion. 3) Aldosterone secretion rate was also increase d during furosemide diuresis, but the rate was smaller than that of urinary excretion. 4) Continuous modest increase in aldosterone secretion rate was shown after diuresis and total excess amount of aldosterone secretion for 24 hrs was equivalent to the amount of aldosterone excretion produced by diruesis. 5) Abrupt marked loss of circulating aldosterone produced by diuresis was supplemented by long lasting increase in secretion for over twenty four hours.

  11. Error rates of a full-duplex system over EGK fading channels subject to laplacian interference

    KAUST Repository

    Soury, Hamza; Elsawy, Hesham; Alouini, Mohamed-Slim

    2017-01-01

    modulation schemes is studied and a unified closed-form expression for the average symbol error rate is derived. To this end, we show the effective downlink throughput gain, harvested by employing FD communication at a BS that serves HD users, as a function

  12. Cortical atrophy rates in Alzheimer's patients and subjects with mild cognitive impairment from the AddNeuroMed data collection

    DEFF Research Database (Denmark)

    Eskildsen, Simon Fristed; Westman, Eric; Gwadry-Sridhar, Femida

    2010-01-01

    Background: The AddNeuroMed project is a multi-centre European project which aims to identify biomarkers in Alzheimer's disease (AD). In this study we measured the rate of cortical atrophy in AD patients, subjects with mild cognitive impairment (MCI), and healthy controls (HC) using MRI. Methods...... quality control for both the acquisition and image processing were included in the study. Cortical thickness was measured using FACE (fast accurate cortex extraction) and averaged within main lobes using a stereotaxic atlas. Atrophy rates were calculated as percent decrease in cortical thickness and rate...

  13. [Stress and night eating syndrome: a comparison study between a sample of psychiatric outpatients and healthy subjects].

    Science.gov (United States)

    Pacitti, Francesca; Maraone, Annalisa; Zazzara, Francesca; Biondi, Massimo; Caredda, Maria

    2011-01-01

    The Night Eating Syndrome (NES) is a disorder characterized by the clinical features of morning anorexia, evening hyperphagia, and insomnia with awakenings followed by nocturnal food ingestion. The core clinical feature appears to be a delay in the circadian timing of food intake. The diagnosis and early treatment of NES may represent an important means of prevention for obesity. Aims. The aim of the present study was to determine the vulnerability to develop NES between a clinical sample of patients with psychiatric disorders and a non clinical sample. We investigated a possible relation between stress and a dysfunctional eating behaviors as NES. Methods. The Night Eating Questionnaire (NEQ) has been administered to 147 psychiatric outpatients and to 531 subjects attending the University of L'Aquila. The NEQ is a questionnaire used to evaluate the prevalence of NES. The sample has been also evaluated through the Stress-related Vulnerability Scale (SVS) to measure both perceived stress and social support. Results. The 8.2% of patients scored above the diagnostic cut-off of the NEQ, compared to the 2.1% in the sample of healthy subjects. The majority of patients who had shown NEQ>25 had a diagnosis of major depressive disorder (MDD). The total scores on the NEQ were strongly associated with the SVS total score and especially with the "lack of social support" subscale. Conclusions. This study shows the increased vulnerability of NES in the sample of psychiatric patients compared to the sample of healthy subjects. The study further confirms the strong association between perceived stress, social support, altered eating behaviors and obesity.

  14. Constitutive relationships for ocean sediments subjected to stress and temperature gradients

    International Nuclear Information System (INIS)

    Davies, T.G.; Banerjee, P.K.

    1980-08-01

    The disposal of low-level nuclear wastes by burial in deep sea sediments is an option currently being considered. This report lays the groundwork for an investigation of the stability of canisters containing nuclear wastes against movement due to fluidisation of the surrounding sediments, where such fluidisation may result from thermally induced stresses. The requisite constitutive relationships for ocean sediments under stress and temperature gradients are derived from the theory of critical state soil mechanics. A parametric survey has been made of the behaviour of an element of soil in order to assess various models and the importance of the governing parameters, The formulation of a finite element algorithm is given for the solution of the sediment stability problem. (author)

  15. Assessing and improving health in the workplace: an integration of subjective and objective measures with the STress Assessment and Research Toolkit (St.A.R.T. method

    Directory of Open Access Journals (Sweden)

    Panari Chiara

    2012-09-01

    Full Text Available Abstract Background The aim of this work was to introduce a new combined method of subjective and objective measures to assess psychosocial risk factors at work and improve workers’ health and well-being. In the literature most of the research on work-related stress focuses on self-report measures and this work represents the first methodology capable of integrating different sources of data. Method An integrated method entitled St.A.R.T. (STress Assessment and Research Toolkit was used in order to assess psychosocial risk factors and two health outcomes. In particular, a self-report questionnaire combined with an observational structured checklist was administered to 113 workers from an Italian retail company. Results The data showed a correlation between subjective data and the rating data of the observational checklist for the psychosocial risk factors related to work contexts such as customer relationship management and customer queue. Conversely, the factors related to work content (workload and boredom measured with different methods (subjective vs. objective showed a discrepancy. Furthermore, subjective measures of psychosocial risk factors were more predictive of workers’ psychological health and exhaustion than rating data. The different objective measures played different roles, however, in terms of their influence on the two health outcomes considered. Conclusions It is important to integrate self-related assessment of stressors with objective measures for a better understanding of workers’ conditions in the workplace. The method presented could be considered a useful methodology for combining the two measures and differentiating the impact of different psychological risk factors related to work content and context on workers’ health.

  16. Assessing and improving health in the workplace: an integration of subjective and objective measures with the STress Assessment and Research Toolkit (St.A.R.T.) method.

    Science.gov (United States)

    Panari, Chiara; Guglielmi, Dina; Ricci, Aurora; Tabanelli, Maria Carla; Violante, Francesco Saverio

    2012-09-20

    The aim of this work was to introduce a new combined method of subjective and objective measures to assess psychosocial risk factors at work and improve workers' health and well-being. In the literature most of the research on work-related stress focuses on self-report measures and this work represents the first methodology capable of integrating different sources of data. An integrated method entitled St.A.R.T. (STress Assessment and Research Toolkit) was used in order to assess psychosocial risk factors and two health outcomes. In particular, a self-report questionnaire combined with an observational structured checklist was administered to 113 workers from an Italian retail company. The data showed a correlation between subjective data and the rating data of the observational checklist for the psychosocial risk factors related to work contexts such as customer relationship management and customer queue. Conversely, the factors related to work content (workload and boredom) measured with different methods (subjective vs. objective) showed a discrepancy. Furthermore, subjective measures of psychosocial risk factors were more predictive of workers' psychological health and exhaustion than rating data. The different objective measures played different roles, however, in terms of their influence on the two health outcomes considered. It is important to integrate self-related assessment of stressors with objective measures for a better understanding of workers' conditions in the workplace. The method presented could be considered a useful methodology for combining the two measures and differentiating the impact of different psychological risk factors related to work content and context on workers' health.

  17. Influence of Subjectivity in Geological Mapping on the Net Penetration Rate Prediction for a Hard Rock TBM

    Science.gov (United States)

    Seo, Yongbeom; Macias, Francisco Javier; Jakobsen, Pål Drevland; Bruland, Amund

    2018-05-01

    The net penetration rate of hard rock tunnel boring machines (TBM) is influenced by rock mass degree of fracturing. This influence is taken into account in the NTNU prediction model by the rock mass fracturing factor ( k s). k s is evaluated by geological mapping, the measurement of the orientation of fractures and the spacing of fractures and fracture type. Geological mapping is a subjective procedure. Mapping results can therefore contain considerable uncertainty. The mapping data of a tunnel mapped by three researchers were compared, and the influence of the variation in geological mapping was estimated to assess the influence of subjectivity in geological mapping. This study compares predicted net penetration rates and actual net penetration rates for TBM tunneling (from field data) and suggests mapping methods that can reduce the error related to subjectivity. The main findings of this paper are as follows: (1) variation of mapping data between individuals; (2) effect of observed variation on uncertainty in predicted net penetration rates; (3) influence of mapping methods on the difference between predicted and actual net penetration rate.

  18. Carcass composition of market weight pigs subjected to heat stress in utero and during finishing.

    Science.gov (United States)

    Cruzen, S M; Boddicker, R L; Graves, K L; Johnson, T P; Arkfeld, E K; Baumgard, L H; Ross, J W; Safranski, T J; Lucy, M C; Lonergan, S M

    2015-05-01

    Objectives were to investigate the effects of prolonged gestational and/or postnatal heat stress on performance and carcass composition of market weight pigs. Pregnant gilts were exposed to gestational heat stress (GHS, 28°C to 34°C, diurnal) or thermal neutral (18°C to 22°C, diurnal) conditions during the entire gestation or during the first or second half of gestation. At 14 wk of age (58 ± 5 kg), barrows were housed in heat stress (32°C, HS) or thermal neutral (21°C, TN) conditions. Feed intake and BW were recorded weekly, and body temperature parameters were monitored twice weekly until slaughter (109 ± 5 kg). Organs were removed and weighed, and loin eye area (LEA) and back fat thickness (BF) were measured after carcass chilling. Carcass sides were separated into lean, separable fat, bone, and skin components and were weighed. Moisture, lipid, and protein content were determined in the LM at the 10th rib. Data were analyzed using a split plot with random effect of dam nested within gestational treatment. Carcass measurements included HCW as a covariate to control for weight. Planned orthogonal contrast statements were used to evaluate the overall effect of GHS in the first half, second half, or any part of gestation. Gestational heat stress did not alter postnatal performance or most body temperature parameters (P > 0.10). However, ADFI in the finishing period was increased (P carcasses (P = 0.38). Carcasses from HS barrows also had less carcass separable fat (P carcasses had a greater moisture to protein ratio (P = 0.04). HS barrows also had decreased heart (P carcass composition. Chronic HS during finishing results in longer times to reach market weight and a leaner carcass once market weight is achieved.

  19. Analysis of the temperature and stress distributions in ceramic window materials subjected to microwave heating

    International Nuclear Information System (INIS)

    Ferber, M.K.; Kimrey, H.D.; Becher, P.F.

    1983-07-01

    The temperature and stress and distributions generated in ceramic materials currently employed in microwave gyrotron tube windows were determined for a variety of operating conditions. Both edge- and face-cooled windows of either polycrystalline BeO or polycrystalline Al 2 O 3 were considered. The actual analysis involved three steps. First, a computer program was used to determine the electric field distribution within the window at a given power level and frequency (TE 02 wave propagation assumed). This program was capable of describing both the radial and axial dependence of the electric field. The effects of multiple internal reflections at the various dielectric interfaces were also accounted for. Secondly, the field distribution was used to derive an expression for the heat generated per unit volume per unit time within the window due to dieletric losses. A generalized heat conduction computer code was then used to compute the temperature distribution based on the heat generation function. Third, the stresses were determined from the temperature profiles using analytical expression or a finite-element computer program. Steady-state temperature and stress profiles were computed for the face-cooled and edge-cooled windows

  20. Spectral changes in conifers subjected to air pollution and water stress: Experimental studies

    Science.gov (United States)

    Westman, Walter E.; Price, Curtis V.

    1988-01-01

    The roles of leaf anatomy, moisture and pigment content, and number of leaf layers on spectral reflectance in healthy, pollution-stressed, and water-stressed conifer needles were examined experimentally. Jeffrey pine (Pinus jeffreyi) and giant sequoia (Sequoiadendron gigantea) were exposed to ozone and acid mist treatments in fumigation chambers; red pine (Pinus resinosa) needles were artificially dried. Infrared reflectance from stacked needles rose with free water loss. In an air-drying experiment, cell volume reductions induced by loss of turgor caused near-infrared reflectance (TM band 4) to drop after most free water was lost. Under acid mist fumigation, stunting of tissue development similarly reduced band 4 reflectance. Both artificial drying and pollutant fumigation caused a blue shift of the red edge of spectral reflectance curves in conifers, attributable to chlorophyll denaturation. Thematic mapper band ratio 4/3 fell and 5/4 rose with increasing pollution stress on artificial drying. Loss of water by air-drying, freeze-drying, or oven-drying enhanced spectral features, due in part to greater scattering and reduced water absorption. Grinding of the leaf tissue further enhanced the spectral features by increasing reflecting surfaces and path length. In a leaf-stacking experiment, an asymptote in visible and infrared reflectance was reached at 7-8 needle layers of red pine.

  1. Relationship among perceived stress, xerostomia, and salivary flow rate in patients visiting a saliva clinic.

    Science.gov (United States)

    Bulthuis, Marjolein S; Jan Jager, Derk H; Brand, Henk S

    2018-03-09

    This aimed to assess the potential role of chronic stress in saliva secretion, xerostomia, and oral health in a population attending a saliva clinic. Data of 114 patients who met the inclusion criteria and completed all questionnaires were analyzed in this study. Participants completed several validated questionnaires, including the Perceived Stress Scale, the Oral Health Impact Profile (OHIP-14), Xerostomia Inventory (XI), and Bother xerostomia Index (BI). Subsequently, the unstimulated, chewing-stimulated, and citric acid-stimulated saliva secretion rates were determined gravimetrically. Data were evaluated using Spearman's correlation analysis and the Mann-Whitney U test. A significant correlation was observed between perceived stress and XI score (r = 0.312, p = 0.001), as well as between perceived stress and BI score (r = 0.334, p = 0.001). Stress levels also were significantly associated with OHIP-14 scores (r = 0.420, p stress and salivary flow rate could not be established. In this population, perceived chronic stress seems to be related to several aspects of dry mouth, including the perception of dry mouth, suffering from dry mouth, and the impact on quality of life. These effects were independent of the use of psychotropic medication. No actual reduction in salivary flow was found. Further studies to explore the causal linkage of stress with xerostomia seem warranted. Perceived chronic stress seems to be related with several aspects of dry mouth. This finding might be relevant in future prevention and treatment of xerostomia.

  2. Disaggregating Within- and Between-Person Effects of Social Identification on Subjective and Endocrinological Stress Reactions in a Real-Life Stress Situation.

    Science.gov (United States)

    Ketturat, Charlene; Frisch, Johanna U; Ullrich, Johannes; Häusser, Jan A; van Dick, Rolf; Mojzisch, Andreas

    2016-02-01

    Several experimental and cross-sectional studies have established the stress-buffering effect of social identification, yet few longitudinal studies have been conducted within this area of research. This study is the first to make use of a multilevel approach to disaggregate between- and within-person effects of social identification on subjective and endocrinological stress reactions. Specifically, we conducted a study with 85 prospective students during their 1-day aptitude test for a university sports program. Ad hoc groups were formed, in which students completed several tests in various disciplines together. At four points in time, salivary cortisol, subjective strain, and identification with their group were measured. Results of multilevel analyses show a significant within-person effect of social identification: The more students identified with their group, the less stress they experienced and the lower their cortisol response was. Between-person effects were not significant. Advantages of using multilevel approaches within this field of research are discussed. © 2015 by the Society for Personality and Social Psychology, Inc.

  3. A study of diurnal variation in peak expiratory flow rates in healthy adult female subjects in South India

    Directory of Open Access Journals (Sweden)

    Jenny Jayapal

    2014-01-01

    Full Text Available Background: Peak Expiratory Flow Rate (PEFR reflects the strength and condition of respiratory muscles and the degree of airflow limitation in large airways. PEFR shows hour to hour variation that follows a specific pattern in asthmatics and healthy individuals. Adequate data is not available for the diurnal variation in normal individuals who are students in professional courses and had a sedentary life style. Hence, this study was undertaken to study the diurnal variation in peak expiratory flow rates in healthy adult female subjects in South India. Materials and Methods: Peak expiratory flow rate was recorded in 50 adult healthy female students aged 18-23 years and studying in professional courses. Mini Wright′s peak flow meter was used to measure the peak expiratory flow rate. PEFR were recorded at 7-8 a.m., 10-11 a.m., 1-2 p.m., 4-5 p.m., and 7-8 p.m. for two consecutive days. Results: On analysis of PEFR records of individual subjects, it was seen that there was an overall dip in the morning at 7-8 h PEFR, which increased in the daytime, peaking in the afternoon at 1-2 p.m. and eventually decreased in the night. Subjects did not show the peak PEFR values at the same time point, 10% of subjects had a rise in PEFR in the early morning, afternoon (1-2 p.m. peak was observed in 48% subjects and evening (4-5 p.m. peak was observed in 16% subjects. 14% subjects showed a peak in the night time (7-8 p.m. PEFR values. Conclusion: This study provided the preliminary reference data of diurnal variation of peak expiratory flow rate in healthy adults. Since, there is a variation in the peak expiratory flow rate recorded during different time points of the day; hence, to compare the PEFR between individuals it is advisable to record the PEFR at the same time point.

  4. Error rates of a full-duplex system over EGK fading channels subject to laplacian interference

    KAUST Repository

    Soury, Hamza

    2017-07-31

    This paper develops a mathematical paradigm to study downlink error rates and throughput for half-duplex (HD) terminals served by a full-duplex (FD) base station (BS). Particularly, we study the dominant intra-cell interferer problem that appears between HD users scheduled on the same FD-channel. The distribution of the dominant interference is first characterized via its distribution function, which is derived in closed-form. Assuming Nakagami-m fading, the probability of error for different modulation schemes is studied and a unified closed-form expression for the average symbol error rate is derived. To this end, we show the effective downlink throughput gain, harvested by employing FD communication at a BS that serves HD users, as a function of the signal-to-interference-ratio when compared to an idealized HD interference and noise free BS operation.

  5. On a class of adjustable rate mortgage loans subject to a strict balance principle

    DEFF Research Database (Denmark)

    Astrup Jensen, Bjarne

    We describe the background and the basic funding mechanisms for the type of adjustable rate mortgageloans that were introduced in the Danish market in 1996. Each loan is funded separately by tap issuingpass-through mortgage bonds (`strict balance principle'). The novelty is a funding mechanism...... that usesa roll-over strategy, where long term loans are funded by sequentially issuing short term pass-throughbonds, and the first issuer of these loans obtained a patent on the funding principles in 1999. Publiclyavailable descriptions of the principles leave an impression of very complicated numerical...... algorithms.The algorithms described here show that the essentials can be reduced to a `back of an envelope' complexity.Keywords: Adjustable rate mortgages, balance principle, patent, yield curve riding...

  6. FEM Modeling of In-Plane Stress Distribution in Thick Brittle Coatings/Films on Ductile Substrates Subjected to Tensile Stress to Determine Interfacial Strength.

    Science.gov (United States)

    Wang, Kaishi; Zhang, Fangzhou; Bordia, Rajendra K

    2018-03-27

    The ceramic-metal interface is present in various material structures and devices that are vulnerable to failures, like cracking, which are typically due to their incompatible properties, e.g., thermal expansion mismatch. In failure of these multilayer systems, interfacial shear strength is a good measure of the robustness of interfaces, especially for planar films. There is a widely-used shear lag model and method by Agrawal and Raj to analyse and measure the interfacial shear strength of thin brittle film on ductile substrates. The use of this classical model for a type of polymer derived ceramic coatings (thickness ~18 μm) on steel substrate leads to high values of interfacial shear strength. Here, we present finite element simulations for such a coating system when it is subjected to in-plane tension. Results show that the in-plane stresses in the coating are non-uniform, i.e., varying across the thickness of the film. Therefore, they do not meet one of the basic assumptions of the classical model: uniform in-plane stress. Furthermore, effects of three significant parameters, film thickness, crack spacing, and Young's modulus, on the in-plane stress distribution have also been investigated. 'Thickness-averaged In-plane Stress' (TIS), a new failure criterion, is proposed for estimating the interfacial shear strength, which leads to a more realistic estimation of the tensile strength and interfacial shear strength of thick brittle films/coatings on ductile substrates.

  7. Diversity of Survival Patterns among Escherichia coli O157:H7 Genotypes Subjected to Food-Related Stress Conditions.

    Science.gov (United States)

    Elhadidy, Mohamed; Álvarez-Ordóñez, Avelino

    2016-01-01

    The purpose of this study was to evaluate the resistance patterns to food-related stresses of Shiga toxin producing Escherichia coli O157:H7 strains belonging to specific genotypes. A total of 33 E. coli O157:H7 strains were exposed to seven different stress conditions acting as potential selective pressures affecting the transmission of E. coli O157:H7 to humans through the food chain. These stress conditions included cold, oxidative, osmotic, acid, heat, freeze-thaw, and starvation stresses. The genotypes used for comparison included lineage-specific polymorphism, Shiga-toxin-encoding bacteriophage insertion sites, clade type, tir (A255T) polymorphism, Shiga toxin 2 subtype, and antiterminator Q gene allele. Bacterial resistance to different stressors was calculated by determining D-values (times required for inactivation of 90% of the bacterial population), which were then subjected to univariate and multivariate analyses. In addition, a relative stress resistance value, integrating resistance values to all tested stressors, was calculated for each bacterial strain and allowed for a ranking-type classification of E. coli O157:H7 strains according to their environmental robustness. Lineage I/II strains were found to be significantly more resistant to acid, cold, and starvation stress than lineage II strains. Similarly, tir (255T) and clade 8 encoding strains were significantly more resistant to acid, heat, cold, and starvation stress than tir (255A) and non-clade 8 strains. Principal component analysis, which allows grouping of strains with similar stress survival characteristics, separated strains of lineage I and I/II from strains of lineage II, which in general showed reduced survival abilities. Results obtained suggest that lineage I/II, tir (255T), and clade 8 strains, which have been previously reported to be more frequently associated with human disease cases, have greater multiple stress resistance than strains of other genotypes. The results from this

  8. Subjective, Autonomic, and Endocrine Reactivity during Social Stress in Children with Social Phobia

    Science.gov (United States)

    Kramer, Martina; Seefeldt, Wiebke Lina; Heinrichs, Nina; Tuschen-Caffier, Brunna; Schmitz, Julian; Wolf, Oliver Tobias; Blechert, Jens

    2012-01-01

    Reports of exaggerated anxiety and physiological hyperreactivity to social-evaluative situations are characteristic of childhood social phobia (SP). However, laboratory research on subjective, autonomic and endocrine functioning in childhood SP is scarce, inconsistent and limited by small sample sizes, limited breadth of measurements, and the use…

  9. Whole canopy gas exchange among elite loblolly pine families subjected to drought stress

    Science.gov (United States)

    Wilson G. Hood; Michael C. Tyree; Dylan N. Dillaway; Michael A. Blazier; Mary Anne Sword Sayer

    2012-01-01

    Future climate change simulations predict that the southeastern United States will experience hydrologic patterns similar to that currently found in the Western Gulf Region, meaning, that planted elite loblolly families may be subject to drier, hotter summers (Ruosteenoja et al. 2003, Field et al. 2007). Currently, there is little research on how these fast-growing...

  10. Constraining friction, dilatancy and effective stress with earthquake rates in the deep crust

    Science.gov (United States)

    Beeler, N. M.; Thomas, A.; Burgmann, R.; Shelly, D. R.

    2015-12-01

    Similar to their behavior on the deep extent of some subduction zones, families of recurring low-frequency earthquakes (LFE) within zones of non-volcanic tremor on the San Andreas fault in central California show strong sensitivity to stresses induced by the tides. Taking all of the LFE families collectively, LFEs occur at all levels of the daily tidal stress, and are in phase with the very small, ~200 Pa, shear stress amplitudes while being uncorrelated with the ~2 kPa tidal normal stresses. Following previous work we assume LFE sources are small, persistent regions that repeatedly fail during shear within a much larger scale, otherwise aseismically creeping fault zone and that the correlation of LFE occurrence reflects modulation of the fault creep rate by the tidal stresses. We examine the predictions of laboratory-observed rate-dependent dilatancy associated with frictional slip. The effect of dilatancy hardening is to damp the slip rate, so high dilatancy under undrained pore pressure reduces modulation of slip rate by the tides. The undrained end-member model produces: 1) no sensitivity to the tidal normal stress, as first suggested in this context by Hawthorne and Rubin [2010], and 2) fault creep rate in phase with the tidal shear stress. Room temperature laboratory-observed values of the dilatancy and friction coefficients for talc, an extremely weak and weakly dilatant material, under-predict the observed San Andreas modulation at least by an order of magnitude owing to too much dilatancy. This may reflect a temperature dependence of the dilatancy and friction coefficients, both of which are expected to be zero at the brittle-ductile transition. The observed tidal modulation constrains the product of the friction and dilatancy coefficients to be at most 5 x 10-7 in the LFE source region, an order of magnitude smaller than observed at room temperature for talc. Alternatively, considering the predictions of a purely rate-dependent talc friction would

  11. Assessment of the behavior of reinforced concrete beams retrofitted with pre-stressed CFPR subjected to cyclic loading

    Science.gov (United States)

    Hojatkashani, Ata; Zanjani, Sara

    2018-03-01

    Rehabilitation of weak and damaged structures has been considered widely during recent years. A relatively modern way of strengthening concrete components is to confine parts under tension and shear by means of carbon fiber reinforce polymer (CFRP). This way of strengthening due to the conditions of composite materials such as light weight, linear elastic behavior until failure point, high tensile strength, high elastic modulus, resistance against corrosion, and high fatigue resistance has become so common. During structural strengthening by means of not pre-stressed FRP materials, usually, it is not possible to benefit from the maximum capacity of FRP materials. In addition, sometimes, the expensive cost of such materials will not make a suitable balance between rates of strengthening and consuming spending. Thus, pre-stressing CFRP materials has an undeniable role in the effective use of materials. In the current research, general procedure of simulation using finite-element method (FEM) by means of the numerical package ABAQUS has been presented. In this article, 12 reinforced concrete (RC) models in two states (strengthened with simple and pre-stressed CFRP) under cycling loading have been considered. A parametric study has been carried out in this research on the effects of parameters such as CFRP surface area, percentage of tensile steel rebar and pre-stressing stress on ultimate load carrying capacity (ULCC), stiffness, and the ability of depreciation energy for the samples. In the current article also, for design parameters, percentages of tensile steel rebars, surface area of CFPR sheets, and the effective pre-stressing stress in RC beams retrofitted with pre-stressed CFPR sheets have investigated. In this paper, it was investigated that using different amount of parameters such as steel rebar percentage, CFRP surface area percentage, and CFRP pre-stressing, the resulted ULCC and energy depreciation of the specimens was observed to be increasing and

  12. Cyclic behavior of Ta at low temperatures under low stresses and strain rates

    International Nuclear Information System (INIS)

    Stickler, C.; Knabl, W.; Stickler, R.; Weiss, B.

    2001-01-01

    The cyclic stress-strain response of recrystallized technically pure Ta was investigated in the stress range well below the technical flow stress, for temperatures between 173 K and 423 K, at loading rates between 0.042 Mpa/s and 4.2 Mpa/s with resulting plastic strains between -5 up to 1X10 -2 . Cyclic hardening-softening curves were recorded in multiple step tests. Cyclic stress strain curves exhibit straight portions associated with microplastic, transition range and macroplastic deformation mechanisms. The microstructure of the deformed specimens was characterized by SEM and TEM techniques which revealed typical dislocation arrangements related to plastic strain amplitudes and test temperatures. A mechanism of the microstrain deformation of Ta is proposed. (author)

  13. Change of digesta passage rate in dairy cows after different acute stress situations

    Directory of Open Access Journals (Sweden)

    G. Bertoni

    2010-04-01

    Full Text Available Six dairy cows received 3 treatments after morning meal, in a double Latin square design. Treatments were ACTH challenge (SYN, hoof trimming (TRIM and saline (CTR. Measurements included: plasma cortisol and metabolic profile during the 24 h after treatments; the rate of digesta passage, faecal dry matter and pH. Both acute stress situations vs CTR caused a rapid and similar rise in plasma cortisol (P<0.001, while plasma glucose increased only in response to TRIM. Plasma concentrations of urea and BHB were increased for several hours after both stress situations. Most importantly, the transit time of digesta was reduced with SYN and TRIM (P<0.05. Our data demonstrate a reduced forestomach motility during acute stress and confirm a possible negative linkage between stress and gut functions, perhaps independent of diet composition. The mechanism seems linked to increased ACTH or cortisol rather than corticotrophin-releasing factor.

  14. Automatic stress-relieving music recommendation system based on photoplethysmography-derived heart rate variability analysis.

    Science.gov (United States)

    Shin, Il-Hyung; Cha, Jaepyeong; Cheon, Gyeong Woo; Lee, Choonghee; Lee, Seung Yup; Yoon, Hyung-Jin; Kim, Hee Chan

    2014-01-01

    This paper presents an automatic stress-relieving music recommendation system (ASMRS) for individual music listeners. The ASMRS uses a portable, wireless photoplethysmography module with a finger-type sensor, and a program that translates heartbeat signals from the sensor to the stress index. The sympathovagal balance index (SVI) was calculated from heart rate variability to assess the user's stress levels while listening to music. Twenty-two healthy volunteers participated in the experiment. The results have shown that the participants' SVI values are highly correlated with their prespecified music preferences. The sensitivity and specificity of the favorable music classification also improved as the number of music repetitions increased to 20 times. Based on the SVI values, the system automatically recommends favorable music lists to relieve stress for individuals.

  15. [Corrective effect of aromatherapy on indices of heart rate variability in students under exam stress conditions].

    Science.gov (United States)

    Abrahamyan, H T; Minasyan, S M

    2016-01-01

    There were investigated changes in indices of the activity of regulatory mechanisms of heart rhythm in student under exam stress conditions and the possibility of their correction with aid of aromatherapy. The examination stress was established to be accompanied by pronounced shifts of integral and spectral indices of heart rhythm in students, indicating to the activation of the sympathetic circuit of Autonomic Nervous System in conditions of examination stress. A positive, relaxation impact of the essential oil of orange on the investigated indices was also recorded. The latter is expressed by weakly pronounced changes or lack of them in data of integral and spectral heart rate indices in students from the experimental group, that indicates to the stabilizing effect of used ethereal oil on the psycho-physiological state of students in conditions of exam stress

  16. Steady thermal stress and strain rates in a rotating circular cylinder under steady state temperature

    Directory of Open Access Journals (Sweden)

    Pankaj Thakur

    2014-01-01

    Full Text Available Thermal stress and strain rates in a thick walled rotating cylinder under steady state temperature has been derived by using Seth’s transition theory. For elastic-plastic stage, it is seen that with the increase of temperature, the cylinder having smaller radii ratios requires lesser angular velocity to become fully plastic as compared to cylinder having higher radii ratios The circumferential stress becomes larger and larger with the increase in temperature. With increase in thickness ratio stresses must be decrease. For the creep stage, it is seen that circumferential stresses for incompressible materials maximum at the internal surface as compared to compressible material, which increase with the increase in temperature and measure n.

  17. AMF Inoculation Enhances Growth and Improves the Nutrient Uptake Rates of Transplanted, Salt-Stressed Tomato Seedlings

    Directory of Open Access Journals (Sweden)

    Astrit Balliu

    2015-12-01

    Full Text Available The study aimed to investigate the effects of commercially available AMF inoculate (Glomus sp. mixture on the growth and the nutrient acquisition in tomato (Solanumlycopersicum L. plants directly after transplanting and under different levels of salinity. Inoculated (AMF+ and non-inoculated (AMF− tomato plants were subjected to three levels of NaCl salinity (0, 50, and 100 mM·NaCl. Seven days after transplanting, plants were analyzed for dry matter and RGR of whole plants and root systems. Leaf tissue was analyzed for mineral concentration before and after transplanting; leaf nutrient content and relative uptake rates (RUR were calculated. AMF inoculation did not affect plant dry matter or RGR under fresh water-irrigation. The growth rate of AMF−plants did significantly decline under both moderate (77% and severe (61% salt stress compared to the fresh water-irrigated controls, while the decline was much less (88% and 75%,respectivelyand statistically non-significant in salt-stressed AMF+ plants. Interestingly, root system dry matter of AMF+ plants (0.098 g plant–1 remained significantly greater under severe soil salinity compared to non-inoculated seedlings (0.082 g plant–1. The relative uptake rates of N, P, Mg, Ca, Mn, and Fe were enhanced in inoculated tomato seedlings and remained higher under (moderate salt stress compared to AMF− plants This study suggests that inoculation with commercial AMF during nursery establishment contributes to alleviation of salt stress by maintaining a favorable nutrient profile. Therefore, nursery inoculation seems to be a viable solution to attenuate the effects of increasing soil salinity levels, especially in greenhouses with low natural abundance of AMF spores.

  18. Study on influence of flow rates on voids in waxy crude oil subjected to dynamic and static cooling

    Directory of Open Access Journals (Sweden)

    Girma T. Chala

    2015-12-01

    Full Text Available The assumption of constant yield stress in the conventional restart pressure equation neglects the effects of thermal shrinkage and gas voids formation, which in turn resulted in an over-designed production piping systems. This paper presents a study on the effects of flow rates on the formation of voids in gelled waxy crude oil. A flow loop rig simulating offshore waxy crude oil transportation was used to produce a gel. A Magnetic Resonance Imaging (MRI was used to scan the gelled crude oil over the three planes. Waxy crude oil underwent both dynamic and static cooling to observe the effects of volume flow rates on the voids formed in wax-oil gel. Volume flow rate was found to have different influences on the intra-gel voids in the pipeline. A volume flow rate of 5 L/min resulted in a maximum total voids volume of 6.98% while 20 L/min produced a minimum total voids volume of 5.67% in the entire pipe. Slow flow rates resulted in a larger voids volume near the pipe wall. In contrast, faster flow rates produced insignificantly higher voids volume around pipe core. Generally, slower flow rates favoured the formation of higher total voids volume following sufficient steady time of wax crystal formation, producing larger voids areas in gelled waxy crude oil.

  19. Citation rate and perceived subject bias in the amphibian-decline literature.

    Science.gov (United States)

    Ohmer, Michel E; Bishop, Phillip J

    2011-02-01

    As a result of global declines in amphibian populations, interest in the conservation of amphibians has grown. This growth has been fueled partially by the recent discovery of other potential causes of declines, including chytridiomycosis (the amphibian chytrid, an infectious disease) and climate change. It has been proposed that researchers have shifted their focus to these novel stressors and that other threats to amphibians, such as habitat loss, are not being studied in proportion to their potential effects. We tested the validity of this proposal by reviewing the literature on amphibian declines, categorizing the primary topic of articles within this literature (e.g., habitat loss or UV-B radiation) and comparing citation rates among articles on these topics and impact factors of journals in which the articles were published. From 1990 to 2009, the proportion of papers on habitat loss remained fairly constant, and although the number of papers on chytridiomycosis increased after the disease was described in 1998, the number of published papers on amphibian declines also increased. Nevertheless, papers on chytridiomycosis were more highly cited than papers not on chytridiomycosis and were published in journals with higher impact factors on average, which may indicate this research topic is more popular in the literature. Our results were not consistent with a shift in the research agenda on amphibians. We believe the perception of such a shift has been supported by the higher citation rates of papers on chytridiomycosis. ©2010 Society for Conservation Biology.

  20. Objective and subjective rating of tonal noise radiated from UK wind farms

    International Nuclear Information System (INIS)

    1996-01-01

    The radiation of noise to the environment is currently a major issue with regard to U.K. wind farm developments. The reason for this concern is not that wind turbines are unduly noisy, but rather because wind farms are often located in rural areas where background noise levels can fall very low. The fact that background noise levels fall so low in these areas means that the permissible noise radiation from wind farms must also be kept similarly low if nuisance to local residents is to be avoided. However, ensuring that the overall noise level of the wind farm does not exceed the pre-existing background noise level by more than a set amount is not the whole story. Noise radiated from wind turbines can exhibit characteristics that set it apart from the natural background noises typically found in quiet rural areas, where ''natural'' background noises might include the sound of the wind blowing through trees, or the sound of running water. One of the acoustic characteristics that can be attributed to some wind turbines is the radiation of tonal noise from mechanical plant located in the nacelles. It is well accepted that tonal components in otherwise broad band, or ''characterless'', noise, can increase the subjective perception of that noise. Account for increased annoyance due to tones is found in both of the British Standards which relate to environmental noise; BS4142 and BS7445. (UK)

  1. Measurement of urinary albumin excretion rate (AER) in normal and diabetic subjects

    International Nuclear Information System (INIS)

    Giampetro, O.; Clerico, A.; Cruschelli, L.; Miccoli, R.; Dipalma, L.; Navalesi, R.

    1987-01-01

    The chemico-clinical characteristics of two commercial RIA kits for the measurement of urinary albumin excretion in normal and diabetic subjects were compared. The chief difference between the two methods concerns the bound/free separation of the antigen, since one employs the second antybody plus PEG (Sclavo Kit), while the other uses the solid phase [antiserum bound to sepharose (Pharmacia kit)]. The two RIA methods have demonstrated a similar degree of sensitivity, feasibility and cost. The precision of the two RIAs was also similar, although the Sclavo kit has shown a better precision for lower albumin concentrations and the Pharmacia kit for higher values. In diabetic patients, elevated urinary albumin concentrations (>60 mg/L) have been found more frequently than low values (<5 mg/L); hence the Pharmacia kit seems to be preferable, because it less frequently needs dilution of urinary sample for measuring with a better precision supranormal urinary albumin values. A significant bias (about 15%) was found between the two RIAs. Bias between different albumin RIA methods could partially explain the differences of normal values previously reported in the literature

  2. Age, Cumulative Trauma and Stressful Life Events, and Post-Traumatic Stress Symptoms among Older Adults in Prison: Do Subjective Impressions Matter?

    Science.gov (United States)

    Maschi, Tina; Morgen, Keith; Zgoba, Kristen; Courtney, Deborah; Ristow, Jennifer

    2011-01-01

    Background: The aging prison population in the United States presents a significant public health challenge with high rates of trauma and mental health issues that the correctional system alone is ill-prepared to address. The purpose of this study was to examine the relationship of age, objective, and subjective measures of trauma and stressful…

  3. Stress Field Variation after the 2001 Skyros Earthquake, Greece, Derived from Seismicity Rate Changes

    Science.gov (United States)

    Leptokaropoulos, K.; Papadimitriou, E.; Orlecka-Sikora, B.; Karakostas, V.

    2012-04-01

    The spatial variation of the stress field (ΔCFF) after the 2001 strong (Mw=6.4) Skyros earthquake in North Aegean Sea, Greece, is investigated in association with the changes of earthquake production rates. A detailed slip model is considered in which the causative fault is consisted of several sub-faults with different coseismic slip onto each one of them. First the spatial distribution of aftershock productivity is compared with the static stress changes due to the coseismic slip. Calculations of ΔCFF are performed at different depths inside the seismogenic layer, defined from the vertical distribution of the aftershocks. Seismicity rates of the smaller magnitude events with M≥Mc for different time increments before and after the main shock are then derived from the application of a Probability Density Function (PDF). These rates are computed by spatially smoothing the seismicity and for this purpose a normal grid of rectangular cells is superimposed onto the area and the PDF determines seismicity rate values at the center of each cell. The differences between the earthquake occurrence rates before and after the main shock are compared and used as input data in a stress inversion algorithm based upon the Rate/State dependent friction concept in order to provide an independent estimation of stress changes. This model incorporates the physical properties of the fault zones (characteristic relaxation time, fault constitutive parameters, effective friction coefficient) with a probabilistic estimation of the spatial distribution of seismicity rates, derived from the application of the PDF. The stress patterns derived from the previously mentioned approaches are compared and the quantitative correlation between the respective results is accomplished by the evaluation of Pearson linear correlation coefficient and its confidence intervals to quantify their significance. Different assumptions and combinations of the physical and statistical parameters are tested for

  4. Strain Rate Dependent Deformation of a Polymer Matrix Composite with Different Microstructures Subjected to Off-Axis Loading

    Directory of Open Access Journals (Sweden)

    Xiaojun Zhu

    2014-01-01

    Full Text Available This paper aims to investigate the comprehensive influence of three microstructure parameters (fiber cross-section shape, fiber volume fraction, and fiber off-axis orientation and strain rate on the macroscopic property of a polymer matrix composite. During the analysis, AS4 fibers are considered as elastic solids, while the surrounding PEEK resin matrix exhibiting rate sensitivities are described using the modified Ramaswamy-Stouffer viscoplastic state variable model. The micromechanical method based on generalized model of cells has been used to analyze the representative volume element of composites. An acceptable agreement is observed between the model predictions and experimental results found in the literature. The research results show that the stress-strain curves are sensitive to the strain rate and the microstructure parameters play an important role in the behavior of polymer matrix.

  5. Elongational flow of polymer melts at constant strain rate, constant stress and constant force

    Science.gov (United States)

    Wagner, Manfred H.; Rolón-Garrido, Víctor H.

    2013-04-01

    Characterization of polymer melts in elongational flow is typically performed at constant elongational rate or rarely at constant tensile stress conditions. One of the disadvantages of these deformation modes is that they are hampered by the onset of "necking" instabilities according to the Considère criterion. Experiments at constant tensile force have been performed even more rarely, in spite of the fact that this deformation mode is free from necking instabilities and is of considerable industrial relevance as it is the correct analogue of steady fiber spinning. It is the objective of the present contribution to present for the first time a full experimental characterization of a long-chain branched polyethylene melt in elongational flow. Experiments were performed at constant elongation rate, constant tensile stress and constant tensile force by use of a Sentmanat Extensional Rheometer (SER) in combination with an Anton Paar MCR301 rotational rheometer. The accessible experimental window and experimental limitations are discussed. The experimental data are modelled by using the Wagner I model. Predictions of the steady-start elongational viscosity in constant strain rate and creep experiments are found to be identical, albeit only by extrapolation of the experimental data to Hencky strains of the order of 6. For constant stress experiments, a minimum in the strain rate and a corresponding maximum in the elongational viscosity is found at a Hencky strain of the order of 3, which, although larger than the steady-state value, follows roughly the general trend of the steady-state elongational viscosity. The constitutive analysis also reveals that constant tensile force experiments indicate a larger strain hardening potential than seen in constant elongation rate or constant tensile stress experiments. This may be indicative of the effect of necking under constant elongation rate or constant tensile stress conditions according to the Considère criterion.

  6. Major depressive disorder mediates accelerated aging in rats subjected to chronic mild stress.

    Science.gov (United States)

    Xie, Xiaoxian; Chen, Yangyang; Ma, Lingyan; Shen, Qichen; Huang, Liangfeng; Zhao, Binggong; Wu, Tao; Fu, Zhengwei

    2017-06-30

    Major depressive disorder (MDD) has a complex etiology and is characterized by a change in mood and psychophysiological state. MDD has been shown to mediate accelerated biological aging in patients, although the underlying mechanism is not well understood. In the present study, we used a chronic mild stress (CMS) paradigm to induce anhedonia, one of the main symptoms of MDD. CMS induced depression-like symptoms in rats, including reduced sucrose preference and increased immobility time in the forced swim test. Moreover, stressed rats travelled a shorter total distance, had fewer grid line crossings, and spent less time in the outer zone in the open field test than controls. CMS altered the levels of 5-hydroxytryptophan, dopamine, and corticosterone in the serum and hippocampus (P<0.05); these rats also exhibited impaired liver function, decreased telomerase activity, and telomere shortening, which was associated with increased oxidative damage along with decreased superoxide dismutase and glutathione reductase activities. Mitochondria in CMS-treated rats showed ultrastructural damage as well as reduced DNA content and integrity. These findings provide physiological and cellular evidence that the MDD can mediate accelerated aging in rats. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Effects of itopride hydrochloride on plasma gut-regulatory peptide and stress-related hormone levels in healthy human subjects.

    Science.gov (United States)

    Katagiri, Fumihiko; Shiga, Toru; Inoue, Shin; Sato, Yuhki; Itoh, Hiroki; Takeyama, Masaharu

    2006-01-01

    Itopride hydrochloride (itopride), a gastrokinetic drug, has recently been evaluated for its clinical usefulness in functional dyspepsia. We investigated effects of itopride on human plasma gastrin-, somatostatin-, motilin-, and cholecystokinin (CCK)-like immunoreactive substances (IS); adrenocorticotropic hormone (ACTH)-immunoreactive substances (IS), and cortisol under stress conditions in healthy subjects. A single administration of itopride caused significant increases in plasma somatostatin- and motilin-IS levels compared to placebo. Itopride significantly decreased plasma CCK-IS, and suppressed the ACTH-IS level compared to placebo. We hypothesize that itopride may have an accelerating gastric emptying effect, and a modulatory effect on the hypothalamo-pituitary-adrenal axis and autonomic nervous functions. These effects might be beneficial in stress-related diseases, suggesting that itopride has clinicopharmacological activities.

  8. Discrimination, Subjective Wellbeing, and the Role of Gender: A Mediation Model of LGB Minority Stress.

    Science.gov (United States)

    Conlin, Sarah E; Douglass, Richard P; Ouch, Staci

    2017-10-26

    The present study examined the link between discrimination and the three components of subjective wellbeing (positive and negative affect and life satisfaction) among a cisgender sample of lesbian, gay, and bisexual (LGB) adults. Specifically, we investigated internalized homonegativity and expectations of rejection as potential mediators of the links between discrimination and subjective wellbeing among a sample of 215 participants. Results from our structural equation model demonstrated a strong, positive direct link between discrimination and negative affect. Discrimination also had small, negative indirect effects on life satisfaction through our two mediators. Interestingly, neither discrimination nor our two mediators were related with positive affect, demonstrating the need for future research to uncover potential buffers of this link. Finally, our model evidenced configural, metric, and scalar invariance, suggesting that our model applies well for both women and men. Practical implications and future directions for research are discussed.

  9. Complete characteristics of rating estimations economic development of subjects of the Russian Federation

    Directory of Open Access Journals (Sweden)

    Khamid Nurislamovich Gizatullin

    2012-03-01

    Full Text Available This paper allocates complete characteristics of indicators of economic development of subjects of the Russian Federation. Their system representation has appeared more informative, than system of simple social and economic indexes as allows reflecting variety of communications between them, providing preserving and development of researched objects. It is established that at deterioration of state of the economy of regions of their structure change the role in formation of base indicators. At the first stage it is expressed by change of a vector of development with an opposite direction; on the second — in transition from an optimum condition of available structures on periphery; on the third — in the termination of their participation in forming of under laying echelons. At transition of subsystems of social and economic indexes from the first on the second echelon the contribution of the moved potential from structures «resource-product» and «process» for elements of activization increases, for structures «object», on the contrary, decreases, while for final elements the opposite situation is observed. As approaching the top echelon there is a reduction of interaction of base indicators from structures «resource-product» and «process», and on the contrary, growth to structures «object». The conclusion is drawn that successful social and economic activity of regions is determined by synchronous interaction of all allocated structures («resource-product», «process» and «object». Use of the offered algorithm on the basis of complete characteristics allows not only to find out problem regions, but also shows possibility of management on the basis of revealed statistical regularities their condition by forming of optimum mutual relations between the allocated subsystems and, finally, creation of the big possibilities for realization of the having potential

  10. Activities of fructan- and sucrose-metabolizing enzymes in wheat stems subjected to water stress during grain filling.

    Science.gov (United States)

    Yang, Jianchang; Zhang, Jianhua; Wang, Zhiqing; Zhu, Qingsen; Liu, Lijun

    2004-12-01

    This study investigated if a controlled water deficit during grain filling of wheat (Triticum aestivum L.) could accelerate grain filling by facilitating the remobilization of carbon reserves in the stem through regulating the enzymes involved in fructan and sucrose metabolism. Two high lodging-resistant wheat cultivars were grown in pots and treated with either a normal (NN) or high amount of nitrogen (HN) at heading time. Plants were either well-watered (WW) or water-stressed (WS) from 9 days post anthesis until maturity. Leaf water potentials markedly decreased at midday as a result of water stress but completely recovered by early morning. Photosynthetic rate and zeatin + zeatin riboside concentrations in the flag leaves declined faster in WS plants than in WW plants, and they decreased more slowly with HN than with NN when soil water potential was the same, indicating that the water deficit enhanced, whereas HN delayed, senescence. Water stress, both at NN and HN, facilitated the reduction in concentration of total nonstructural carbohydrates (NSC) and fructans in the stems but increased the sucrose level there, promoted the re-allocation of pre-fixed (14)C from the stems to grains, shortened the grain-filling period, and accelerated the grain-filling rate. Grain weight and grain yield were increased under the controlled water deficit when HN was applied. Fructan exohydrolase (FEH; EC 3.2.1.80) and sucrose phosphate synthase (SPS; EC 2.4.1.14) activities were substantially enhanced by water stress and positively correlated with the total NSC and fructan remobilization from the stems. Acid invertase (EC 3.2.1.26) activity was also enhanced by the water stress and associated with the change in fructan concentration, but not correlated with the total NSC remobilization and (14)C increase in the grains. Sucrose:sucrose fructosyltransferase (EC 2.4.1.99) activity was inhibited by the water stress and negatively correlated with the remobilization of carbon reserves

  11. A longitudinal study in youth of heart rate variability at rest and in response to stress

    NARCIS (Netherlands)

    Li, Zhibin; Snieder, Harold; Su, Shaoyong; Ding, Xiuhua; Thayer, Julian F.; Treiber, Frank A.; Wang, Xiaoling

    Background: Few longitudinal studies have examined ethnic and sex differences, predictors and tracking stabilities of heart rate variability (HRV) at rest and in response to stress in youths and young adults. Methods: Two evaluations were performed approximately 1.5 years apart on 399 youths and

  12. Measurement Differences from Rating Posttraumatic Stress Disorder Symptoms in Response to Differentially Distressing Traumatic Events

    Science.gov (United States)

    Elhai, Jon D.; Fine, Thomas H.

    2012-01-01

    The authors explored differences in posttraumatic stress disorder (PTSD) symptoms as a result of rating symptoms from two separate, differentially distressing traumatic events. In an initial sample of 400 nonclinical participants, the authors inquired through a web survey about previous psychological trauma, instructing participants to nominate…

  13. Elastic-plastic potential functionals for rates and increments of stress and strain

    International Nuclear Information System (INIS)

    Feijoo, R.A.; Zouain, N.

    1990-03-01

    In this work attention is focused in the derivation of variational formulations of the constutive relationship in the form of conjugate potential functionals from which stress and strain rates are derived as elements of the corresponding sub-differential sets. The main result obtained is a pair of potential functionals. (A.C.A.S.) [pt

  14. The Effect Of Salinity Stress On Buccal Ventilatory Rate In The ...

    African Journals Online (AJOL)

    The Effect Of Salinity Stress On Buccal Ventilatory Rate In The African Lungfish, Protopterus annectens Owen. AI Okafor, LO Chukwu, LO Chukwu. Abstract. No Abstract. Animal Research International Vol. 2 (1) 2005 pp. 252-254. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL ...

  15. Heart Rate, Stress, and Occupational Noise Exposure among Electronic Waste Recycling Workers.

    Science.gov (United States)

    Burns, Katrina N; Sun, Kan; Fobil, Julius N; Neitzel, Richard L

    2016-01-19

    Electronic waste (e-waste) is a growing occupational and environmental health issue around the globe. E-waste recycling is a green industry of emerging importance, especially in low-and middle-income countries where much of this recycling work is performed, and where many people's livelihoods depend on this work. The occupational health hazards of e-waste recycling have not been adequately explored. We performed a cross-sectional study of noise exposures, heart rate, and perceived stress among e-waste recycling workers at a large e-waste site in Accra, Ghana. We interviewed 57 workers and continuously monitored their individual noise exposures and heart rates for up to 24 h. More than 40% of workers had noise exposures that exceeded recommended occupational (85 dBA) and community (70 dBA) noise exposure limits, and self-reported hearing difficulties were common. Workers also had moderate to high levels of perceived stress as measured via Cohen's Perceived Stress Scale, and reported a variety of symptoms that could indicate cardiovascular disease. Noise exposures were moderately and significantly correlated with heart rate (Spearman's ρ 0.46, p stress, and unfavorable physical working conditions. These findings suggest that occupational and non-occupational noise exposure is associated with elevations in average heart rate, which may in turn predict potential cardiovascular damage.

  16. Hand 'stress' arthritis in young subjects: effects of Flexiqule (pharma-standard Boswellia extract). A preliminary case report.

    Science.gov (United States)

    Belcaro, G; Feragalli, B; Cornelli, U; Dugall, M

    2015-10-22

    This case report (supplement registry study) evaluated subjects with painful 'stress' arthritis of the hand mainly localized at the joints. The patients received a suggestion to follow a rehabilitation plan (standard management; SM). A second group also used the same SM in association with the oral, pharma-standard supplement FlexiQule (Alchem) a new standardized, phytosomal preparation manufactured from the Boswellia plant, which can be used for self-management in inflammatory conditions (150 mg / 3 times daily). The two resulting registry groups included 12 subjects using SM+Flexiqule and and 11 controls (SM only). The groups were comparable. Serology showed no significant alterations: only ESR was slightly elevated (minimal elevation). After 2 weeks, the ESR was normal in the supplement group and mildly elevated in controls (p<0.05%). The decrease in hypertermic areas was greater/faster (p<0.05) in the supplement group. The identification of a working stress and the localization to the dominant hand was comparable in both groups. At 2 weeks, the decrease in pain was significantly faster and more important with the supplement (p<0.05). The hand became more usable in time and the score was better with the supplement (p<0.05). No supplemented patient had to use other drugs, while in the control group 3 subjects eventually used NSAIDs to control pain and stiffness and one used corticosteroids. In conclusion, the natural extract Flexiqule was effective in controlling work-related stress arthritis (without inflammaìtory signs) over a 2 weeks period, better than only Standard Management. More prolonged and larger studies are needed.

  17. Reproducibility of subjective appetite ratings and ad libitum test meal energy intake in overweight and obese males.

    Science.gov (United States)

    Horner, Katy M; Byrne, Nuala M; King, Neil A

    2014-10-01

    To determine whether changes in appetite and energy intake (EI) can be detected and play a role in the effectiveness of interventions, it is necessary to identify their variability under normal conditions. We assessed the reproducibility of subjective appetite ratings and ad libitum test meal EI after a standardised pre-load in overweight and obese males. Fifteen overweight and obese males (BMI 30.3 ± 4.9 kg/m(2), aged 34.9 ± 10.6 years) completed two identical test days, 7 days apart. Participants were provided with a standardised fixed breakfast (1676 kJ) and 5 h later an ad libitum pasta lunch. An electronic appetite rating system was used to assess subjective ratings before and after the fixed breakfast, and periodically during the postprandial period. EI was assessed at the ad libitum lunch meal. Sample size estimates for paired design studies were calculated. Appetite ratings demonstrated a consistent oscillating pattern between test days, and were more reproducible for mean postprandial than fasting ratings. The correlation between ad libitum EI on the two test days was r = 0.78 (P appetite and ad libitum test meal EI in overweight and obese males is comparable to previous reports in normal weight adults. Sample size requirements for studies vary depending on the parameter of interest and sensitivity needed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. The influence of stress, depression, and anxiety on PSA screening rates in a nationally representative sample.

    Science.gov (United States)

    Kotwal, Ashwin A; Schumm, Phil; Mohile, Supriya G; Dale, William

    2012-12-01

    Prostate-specific antigen (PSA) testing for prostate cancer is controversial, with concerning rates of both overscreening and underscreening. The reasons for the observed rates of screening are unknown, and few studies have examined the relationship of psychological health to PSA screening rates. Understanding this relationship can help guide interventions to improve informed decision-making for screening. A nationally representative sample of men 57-85 years old without prostate cancer (N = 1169) from the National Social life, Health and Aging Project was analyzed. The independent relationship of validated psychological health scales measuring stress, anxiety, and depression to PSA testing rates was assessed using multivariable logistic regression analyses. PSA screening rates were significantly lower for men with higher perceived stress [odds ratio (OR) = 0.76, P = 0.006], but not for higher depressive symptoms (OR = 0.89, P = 0.22) when accounting for stress. Anxiety influences PSA screening through an interaction with number of doctor visits (P = 0.02). Among the men who visited the doctor once those with higher anxiety were less likely to be screened (OR = 0.65, P = 0.04). Conversely, those who visited the doctor 10+ times with higher anxiety were more likely to be screened (OR = 1.71, P = 0.04). Perceived stress significantly lowers PSA screening likelihood, and it seems to partly mediate the negative relationship of depression with screening likelihood. Anxiety affects PSA screening rates differently for men with different numbers of doctor visits. Interventions to influence PSA screening rates should recognize the role of the patients' psychological state to improve their likelihood of making informed decisions and improve screening appropriateness.

  19. Subjective social status and trajectories of self-rated health status: a comparative analysis of Japan and the United States.

    Science.gov (United States)

    Takahashi, Yoshimitsu; Fujiwara, Takeo; Nakayama, Takeo; Kawachi, Ichiro

    2017-11-28

    Japanese society is more egalitarian than the United States as is reflected by the lower degree of prevalence of social inequalities in health. We examined whether subjective socioeconomic status is associated with different trajectories of self-rated health (SRH), and whether this relationship differs between the United States and Japan. We analyzed the responses of 3968 Americans from the survey Midlife in the United States, 2004-06, and the responses of 989 Japanese from the survey Midlife in Japan, 2008. We conducted a multilevel analysis with three self-ratings of health (10 years ago, current and 10 years in the future) nested within individuals and nested within 10 levels of subjective social status. Age, sex, educational level and subjective financial situation were adjusted. After making statistical adjustments for confounding variables, respondents in Japan continued to report lower average levels of health. However, the rate of expected decline in SRH over the next decade was strongly socially patterned in the United States, whereas it was not in Japan. The Japanese showed no disparity in the anticipated trajectory of SRH over time, whereas the Americans showed a strong social class gradient in future trajectories of SRH. © The Author 2017. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

  20. Estimation of breathing rate in thermal imaging videos: a pilot study on healthy human subjects.

    Science.gov (United States)

    Barbosa Pereira, Carina; Yu, Xinchi; Czaplik, Michael; Blazek, Vladimir; Venema, Boudewijn; Leonhardt, Steffen

    2017-12-01

    Diverse studies have demonstrated the importance of monitoring breathing rate (BR). Commonly, changes in BR are one of the earliest and major markers of serious complications/illness. However, it is frequently neglected due to limitations of clinically established measurement techniques, which require attachment of sensors. The employment of adhesive pads or thoracic belts in preterm infants as well as in traumatized or burned patients is an additional paramount issue. The present paper proposes a new robust approach, based on data fusion, to remotely monitor BR using infrared thermography (IRT). The algorithm considers not only temperature modulation around mouth and nostrils but also the movements of both shoulders. The data of these four sensors/regions of interest need to be further fused to reach improved accuracy. To investigate the performance of our approach, two different experiments (phase A: normal breathing, phase B: simulation of breathing disorders) on twelve healthy volunteers were performed. Thoracic effort (piezoplethysmography) was simultaneously acquired to validate our results. Excellent agreements between BR estimated with IRT and gold standard were achieved. While in phase A a mean correlation of 0.98 and a root-mean-square error (RMSE) of 0.28 bpm was reached, in phase B the mean correlation and the RMSE hovered around 0.95 and 3.45 bpm, respectively. The higher RMSE in phase B results predominantly from delays between IRT and gold standard in BR transitions: eupnea/apnea, apnea/tachypnea etc. Moreover, this study also demonstrates the capability of IRT to capture varied breathing disorders, and consecutively, to assess respiratory function. In summary, IRT might be a promising monitoring alternative to the conventional contact-based techniques regarding its performance and remarkable capabilities.

  1. Acute Consumption of Resistant Starch Reduces Food Intake but Has No Effect on Appetite Ratings in Healthy Subjects.

    Science.gov (United States)

    Ble-Castillo, Jorge L; Juárez-Rojop, Isela E; Tovilla-Zárate, Carlos A; García-Vázquez, Carlos; Servin-Cruz, Magda Z; Rodríguez-Hernández, Arturo; Araiza-Saldaña, Claudia I; Nolasco-Coleman, Ana M; Díaz-Zagoya, Juan C

    2017-07-04

    Previous studies have shown the benefits of native banana starch (NBS) supplementation in improving glucose metabolism and reducing body weight (BW) in humans. However, the effect of this starch on appetite regulation is unknown. The aim of this study was to examine the effects of NBS rich resistant starch on subjective measurements of appetite, energy intake, and appetite hormones in healthy subjects. Postprandial glucose and insulin responses were also assessed. In a randomized, single-blind, crossover study, 28 healthy young subjects consumed a beverage containing either 40 g of NBS or 40 g of digestible corn starch (DCS) on two separate occasions. Effects on appetite were estimated using visual analogue scales (VAS) and satiety hormone responses. At the end of the intervention, participants were provided with a pre-weighed ad libitum homogeneous test meal. After a washout period of 1 week, subjects received the alternative treatment. NBS supplementation induced a reduction in food intake, glucose area under the curve (AUC)-180 min, and insulin AUC-180 min. However, there was no associated effect on the subjective appetite ratings or gut hormones. NBS supplementation may help to reduce meal size and control BW.

  2. Heart rate during conflicts predicts post-conflict stress-related behavior in greylag geese.

    Directory of Open Access Journals (Sweden)

    Claudia A F Wascher

    Full Text Available BACKGROUND: Social stressors are known to be among the most potent stressors in group-living animals. This is not only manifested in individual physiology (heart rate, glucocorticoids, but also in how individuals behave directly after a conflict. Certain 'stress-related behaviors' such as autopreening, body shaking, scratching and vigilance have been suggested to indicate an individual's emotional state. Such behaviors may also alleviate stress, but the behavioral context and physiological basis of those behaviors is still poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: We recorded beat-to-beat heart rates (HR of 22 greylag geese in response to agonistic encounters using fully implanted sensor-transmitter packages. Additionally, for 143 major events we analyzed the behavior shown by our focal animals in the first two minutes after an interaction. Our results show that the HR during encounters and characteristics of the interaction predicted the frequency and duration of behaviors shown after a conflict. CONCLUSIONS/SIGNIFICANCE: To our knowledge this is the first study to quantify the physiological and behavioral responses to single agonistic encounters and to link this to post conflict behavior. Our results demonstrate that 'stress-related behaviors' are flexibly modulated by the characteristics of the preceding aggressive interaction and reflect the individual's emotional strain, which is linked to autonomic arousal. We found no support for the stress-alleviating hypothesis, but we propose that stress-related behaviors may play a role in communication with other group members, particularly with pair-partners.

  3. Stress Recovery Effects of High- and Low-Frequency Amplified Music on Heart Rate Variability.

    Science.gov (United States)

    Nakajima, Yoshie; Tanaka, Naofumi; Mima, Tatsuya; Izumi, Shin-Ichi

    Sounds can induce autonomic responses in listeners. However, the modulatory effect of specific frequency components of music is not fully understood. Here, we examined the role of the frequency component of music on autonomic responses. Specifically, we presented music that had been amplified in the high- or low-frequency domains. Twelve healthy women listened to white noise, a stress-inducing noise, and then one of three versions of a piece of music: original, low-, or high-frequency amplified. To measure autonomic response, we calculated the high-frequency normalized unit (HFnu), low-frequency normalized unit, and the LF/HF ratio from the heart rate using electrocardiography. We defined the stress recovery ratio as the value obtained after participants listened to music following scratching noise, normalized by the value obtained after participants listened to white noise after the stress noise, in terms of the HFnu, low-frequency normalized unit, LF/HF ratio, and heart rate. Results indicated that high-frequency amplified music had the highest HFnu of the three versions. The stress recovery ratio of HFnu under the high-frequency amplified stimulus was significantly larger than that under the low-frequency stimulus. Our results suggest that the high-frequency component of music plays a greater role in stress relief than low-frequency components.

  4. FEM Modeling of In-Plane Stress Distribution in Thick Brittle Coatings/Films on Ductile Substrates Subjected to Tensile Stress to Determine Interfacial Strength

    Directory of Open Access Journals (Sweden)

    Kaishi Wang

    2018-03-01

    Full Text Available The ceramic-metal interface is present in various material structures and devices that are vulnerable to failures, like cracking, which are typically due to their incompatible properties, e.g., thermal expansion mismatch. In failure of these multilayer systems, interfacial shear strength is a good measure of the robustness of interfaces, especially for planar films. There is a widely-used shear lag model and method by Agrawal and Raj to analyse and measure the interfacial shear strength of thin brittle film on ductile substrates. The use of this classical model for a type of polymer derived ceramic coatings (thickness ~18 μm on steel substrate leads to high values of interfacial shear strength. Here, we present finite element simulations for such a coating system when it is subjected to in-plane tension. Results show that the in-plane stresses in the coating are non-uniform, i.e., varying across the thickness of the film. Therefore, they do not meet one of the basic assumptions of the classical model: uniform in-plane stress. Furthermore, effects of three significant parameters, film thickness, crack spacing, and Young’s modulus, on the in-plane stress distribution have also been investigated. ‘Thickness-averaged In-plane Stress’ (TIS, a new failure criterion, is proposed for estimating the interfacial shear strength, which leads to a more realistic estimation of the tensile strength and interfacial shear strength of thick brittle films/coatings on ductile substrates.

  5. Accelerated Testing Methodology in Constant Stress-Rate Testing for Advanced Structural Ceramics: A Preloading Technique

    Science.gov (United States)

    Choi, Sung R.; Gyekenyesi, John P.; Huebert, Dean; Bartlett, Allen; Choi, Han-Ho

    2001-01-01

    Preloading technique was used as a means of an accelerated testing methodology in constant stress-rate (dynamic fatigue) testing for two different brittle materials. The theory developed previously for fatigue strength as a function of preload was further verified through extensive constant stress-rate testing for glass-ceramic and CRT glass in room temperature distilled water. The preloading technique was also used in this study to identify the prevailing failure mechanisms at elevated temperatures, particularly at lower test rates in which a series of mechanisms would be associated simultaneously with material failure, resulting in significant strength increase or decrease. Two different advanced ceramics including SiC whisker-reinforced composite silicon nitride and 96 wt% alumina were used at elevated temperatures. It was found that the preloading technique can be used as an additional tool to pinpoint the dominant failure mechanism that is associated with such a phenomenon of considerable strength increase or decrease.

  6. A comparison of teacher stress and school climate across schools with different matric success rates

    Directory of Open Access Journals (Sweden)

    Karen Milner

    2008-05-01

    Full Text Available Our aim was to investigate differences in teacher stress and perceptions of school climate among teachers from schools with differing matriculation success rates in the Limpopo province of South Africa. Two schools with matric pass rates of 100% and two schools with matric pass rates of less than 25% were selected from a list of schools provided by the province's Educational District Circuit. The schools were matched in terms of area, size, resources, and equipment. Thirty-three teachers from the high performing schools and forty-two teachers from the poor performing schools participated in the study. Student's t tests were used to assess the differences between the schools on the variables under investigation, and the results showed the teachers' experience of stress across the different schools was not significantly different, but significant differences did emerge with regard to school climate. The implications of these findings for the study population are discussed.

  7. Prefrontal responses to Stroop tasks in subjects with post-traumatic stress disorder assessed by functional near infrared spectroscopy

    Science.gov (United States)

    Yennu, Amarnath; Tian, Fenghua; Smith-Osborne, Alexa; J. Gatchel, Robert; Woon, Fu Lye; Liu, Hanli

    2016-07-01

    Studies on posttraumatic stress disorder (PTSD) showing attentional deficits have implicated abnormal activities in the frontal lobe. In this study, we utilized multichannel functional near-infrared spectroscopy (fNIRS) to investigate selective attention-related hemodynamic activity in the prefrontal cortex among 15 combat-exposed war-zone veterans with PTSD and 13 age- and gender-matched healthy controls. While performing the incongruent Stroop task, healthy controls showed significant activations in the left lateral prefrontal cortex (LPFC) compared to baseline readings. This observation is consistent with previously reported results. In comparison, subjects with PTSD failed to activate left LPFC during the same Stroop task. Our observations may implicate that subjects with PTSD experienced difficulty in overcoming Stroop interference. We also observed significant negative correlation between task reaction times and hemodynamic responses from left LPFC during the incongruent Stroop task in the PTSD group. Regarding the methodology used in this study, we have learned that an appropriate design of Stroop paradigms is important for meeting an optimal cognitive load which can lead to better brain image contrasts in response to Stroop interference between healthy versus PTSD subjects. Overall, the feasibility of fNIRS for studying and mapping neural correlates of selective attention and interference in subjects with PTSD is reported.

  8. ICD-11 Prevalence Rates of Posttraumatic Stress Disorder and Complex Posttraumatic Stress Disorder in a German Nationwide Sample.

    Science.gov (United States)

    Maercker, Andreas; Hecker, Tobias; Augsburger, Mareike; Kliem, Sören

    2018-04-01

    Prevalence rates are still lacking for posttraumatic stress disorder (PTSD) and complex PTSD (CPTSD) diagnoses based on the new ICD-11 criteria. In a nationwide representative German sample (N = 2524; 14-99 years), exposure to traumatic events and symptoms of PTSD or CPTSD were assessed with the International Trauma Questionnaire. A clinical variant of CPTSD with a lower threshold for core PTSD symptoms was also calculated, in addition to conditional prevalence rates dependent on trauma type and differential predictors. One-month prevalence rates were as follows: PTSD, 1.5%; CPTSD, 0.5%; and CPTSD variant, 0.7%. For PTSD, the highest conditional prevalence was associated with kidnapping or rape, and the highest CPTSD rates were associated with sexual childhood abuse or rape. PTSD and CPTSD were best differentiated by sexual violence. Combined PTSD and CPTSD (ICD-11) rates were in the range of previously reported prevalences for unified PTSD (Diagnostic and Statistical Manual of Mental Disorders, 4th Edition; ICD-10). Evidence on differential predictors of PTSD and CPTSD is still preliminary.

  9. Swelling of AISI 304L in response to simultaneous variations in stress and displacement rate

    International Nuclear Information System (INIS)

    Porter, D.L.; Garner, F.A.

    1984-01-01

    The duration of the transient regime of neutron-induced swelling in annealed AISI 304L at 400 0 C is sensitive to both stress and displacement rate variations. The simultaneous application of both variables exerts a synergistic effect on the transient regime. The duration of this regime cannot be reduced below a required intrinsic exposure of approx. 10 dpa, however, which has been found to be characteristic of all Fe-Ni-Cr austenitic alloys. This is four times larger than that currently assumed in the stress-affected swelling equation for 20% cold-worked AISI 316

  10. Stresses, strains, and displacements in a poroelastic layered pavement model subject to a moving load

    International Nuclear Information System (INIS)

    Morshedi, C.

    1982-01-01

    The response of a layered poroelastic halfspace to a progressing normally distributed load applied at the surface is evaluated for the case in which the constant velocity of the moving load is less than that of the elastic waves in each layer. It is assumed that a steady state exists with respect to the coordinate axes attached to a moving load. A three-dimensional problem for Biot's consolidated equations is then solved by taking Fourier transforms in the horizontal directions to evaluate stresses and displacements at any point in the medium. The analysis is illustrated by numerical examples using an algorithm based on one previously developed to calculate the response to a static load for axisymmetric poroelastic layers. To reduce the amount of computation, attention is restricted to a two-dimensional problem in which the load extends infinitely in the transverse direction. Results are presented for two and three-layered pavement models composed of concrete and gravel over a clay subbase responding to moving traffic, but the method is applicable to any number of layers. The effect of varying the velocity of the load and layer properties is observed

  11. Association of salivary calcium, phosphate, pH and flow rate on oral health: A study on 90 subjects.

    Science.gov (United States)

    Fiyaz, Mohamed; Ramesh, Amitha; Ramalingam, Karthikeyan; Thomas, Biju; Shetty, Sucheta; Prakash, Prashanth

    2013-07-01

    This study was designed to compare inorganic salivary calcium, phosphate, flow rate and pH of un-stimulated saliva and oral hygiene of healthy subjects, patients with periodontitis and dental caries and to correlate salivary calcium level with the number of intact teeth. The present study consisted of 90 patients aged between 18 and 55 years and were divided into three groups, periodontitis, dental caries and controls. Oral hygiene index-simplified, probing pocket depth, clinical attachment level and number of teeth present, teeth with active carious lesions were recorded. Salivary flow rate and pH was recorded and subjected to biochemical investigation. Estimation of inorganic calcium and phosphate was performed by colorimetric method. Results showed statistically significant increase in salivary inorganic calcium and phosphate levels, poor oral hygiene status, pH and salivary flow rate in patients with periodontitis when compared with dental caries group and controls. Individuals who have increased salivary inorganic calcium, phosphate, pH, flow rate and maintain poor oral hygiene could be at a higher risk for developing periodontitis and may have less dental caries and more number of intact teeth.

  12. Spectral analyses of systolic blood pressure and heart rate variability and their association with cognitive performance in elderly hypertensive subjects.

    Science.gov (United States)

    Santos, W B; Matoso, J M D; Maltez, M; Gonçalves, T; Casanova, M; Moreira, I F H; Lourenço, R A; Monteiro, W D; Farinatti, P T V; Soares, P P; Oigman, W; Neves, M F T; Correia, M L G

    2015-08-01

    Systolic hypertension is associated with cognitive decline in the elderly. Altered blood pressure (BP) variability is a possible mechanism of reduced cognitive performance in elderly hypertensives. We hypothesized that altered beat-to-beat systolic BP variability is associated with reduced global cognitive performance in elderly hypertensive subjects. In exploratory analyses, we also studied the correlation between diverse discrete cognitive domains and indices of systolic BP and heart rate variability. Disproving our initial hypothesis, we have shown that hypertension and low education, but not indices of systolic BP and heart rate variability, were independent predictors of lower global cognitive performance. However, exploratory analyses showed that the systolic BP variability in semi-upright position was an independent predictor of matrix reasoning (B = 0.08 ± .03, P-value = 0.005), whereas heart rate variability in semi-upright position was an independent predictor of the executive function score (B = -6.36 ± 2.55, P-value = 0.02). We conclude that myogenic vascular and sympathetic modulation of systolic BP do not contribute to reduced global cognitive performance in treated hypertensive subjects. Nevertheless, our results suggest that both systolic BP and heart rate variability might be associated with modulation of frontal lobe cognitive domains, such as executive function and matrix reasoning.

  13. The stresses and displacements in cylindrical shells subject to arbitrary temperature distribution

    International Nuclear Information System (INIS)

    Tabakman, H.D.; Lin, Y.J.

    1977-01-01

    The paper begins with a statement of a reciprocal theorem in thermoelasticity based on a generalization of Betti's Reciprocal Theorem. This is followed by application to the solution of a simply supported thin walled cylindrical shell subject to arbitrary three-dimensional temperature distribution T(x,y,z). The usefulness of the theorem resides in the fact that existing solutions in elasticity may be used to obtain solutions of thermoelastic problems. This characteristic is of great importance, particularly when the temperature distribution is arbitrary, as is often the case in practise, and cannot be expressed in functional form; thus rendering solution of the thermoelastic equations very difficult. With solutions of a wide range of problems in elasticity in existence, application of the thermoelastic theorem is the key to solution of a broad class of problems in thermoelasticity, problems that cannot be solved by the classic process. (Auth.)

  14. Catestatin, vasostatin, cortisol, temperature, heart rate, respiratory rate, scores of the short form of the Glasgow composite measure pain scale and visual analog scale for stress and pain behavior in dogs before and after ovariohysterectomy.

    Science.gov (United States)

    Srithunyarat, Thanikul; Höglund, Odd V; Hagman, Ragnvi; Olsson, Ulf; Stridsberg, Mats; Lagerstedt, Anne-Sofie; Pettersson, Ann

    2016-08-02

    The stress reaction induced by surgery and associated pain may be detrimental for patient recovery and should be minimized. The neuropeptide chromogranin A (CGA) has shown promise as a sensitive biomarker for stress in humans. Little is known about CGA and its derived peptides, catestatin (CST) and vasostatin (VS), in dogs undergoing surgery. The objectives of this study were to investigate and compare concentrations of CGA epitopes CST and VS, cortisol, body temperature, heart rate, respiratory rate, scores of the short form of the Glasgow composite measure pain scale (CMPS-SF) and visual analog scales (VAS) for stress and pain behavior in dogs before and after ovariohysterectomy. Thirty healthy privately owned female dogs admitted for elective ovariohysterectomy were included. Physical examination, CMPS-SF, pain behavior VAS, and stress behavior VAS were recorded and saliva and blood samples were collected before surgery, 3 h after extubation, and once at recall 7-15 days after surgery. Dogs were premedicated with morphine and received carprofen as analgesia for 7 days during the postoperative period. At 3 h after extubation, CMPS-SF and pain behavior VAS scores had increased (p stress behavior VAS scores, temperature, respiratory rate (p stress and pain changed in dogs subjected to ovariohysterectomy. To further evaluate CST and VS usefulness as pain biomarkers, studies on dogs in acute painful situations are warranted.

  15. Quantification of the right ventricular wall using stress myocardial emission computed tomography with thallium-201 in normal subjects

    International Nuclear Information System (INIS)

    Akanabe, Hiroshi; Oshima, Motoo; Sakuma, Sadayuki; Yamamoto, Shuhei; Kawai, Naoki; Sotobata, Iwao

    1985-01-01

    Although many studies of quantitative analysis of left ventricular myocardial wall (LVMW) have been reported using stress thallium-201 (Tl-201), few reports of right ventricular myocardial wall (RVMW) have been estimated. In this study we determined whether single photon emission computed tomography (SPECT) with Tl-201 could accurately define normal range of RVMW in normal subjects. Twelve persons who have no valvular disease, nor coronary artery disease were included in this study. Stress SPECT study was reconstructed to make a short axial images of ventricles. RVMW and LVMW were flagged by mamual. Each ventricle was divided into 36 parts at every 10 degree. Relative activity counts in each ventricle were calculated as a percent counts of maximum counts in left ventricle. The normal range of RVMW with stress SPECT was as follows: anterior wall (33.2 +- 11.4 %, mean +- 2 standard deviation, -62.7 +- 18.4 %), free wall (30.1 +- 12.4 % - 38.5 +- 8.8 %), inferior wall (40.4 +- 7.8 % - 60.0 +- 21.4 %), septal wall (65.2 +- 17.2 % - 71.1 +- 14.2 %). Above the results, SPECT with Tl-201 can accurately define the normal range of RVMW, and this method is usefull to quantify the degree of ischemia and hypertrophy in RVMW. (author)

  16. Behaviour of filamentary MgB2 wires subjected to tensile stress at 4.2 K

    International Nuclear Information System (INIS)

    Kováč, P; Kopera, L; Melišek, T; Hušek, I; Rindfleisch, M; Haessler, W

    2013-01-01

    Different filamentary MgB 2 wires have been subjected to tensile stress at 4.2 K. Stress–strain and critical current versus stress and strain characteristics of wires differing by filament architecture, sheath materials, deformation and heat treatment were measured and compared. It was found that the linear increase of critical current due to the pre-compression effect (ranging from 5% up to ≈20%) is affected by thermal expansion and the strength of used metallic sheaths. The values of irreversible strain ε irr and stress σ irr depend dominantly on the applied outer sheath and its final heat treatment conditions. Consequently, the strain-tolerance of MgB 2 wires is influenced by several parameters and it is difficult to see a clear relation between I c (ε) and σ(ε) characteristics. The lowest ε irr was measured for Monel sheathed wires (0.3–0.6%), medium for GlidCop ® sheath (0.48–0.6%), and the highest ε irr = 0.6–0.9% were obtained for MgB 2 wires reinforced by the stainless steel 316L annealed at temperature between 600 and 800 ° C. The highest ε irr = 0.9% and σ irr = 900 MPa were measured for the work-hardened steel, which is not considerably softened by the heat treatment at 600 ° C/2.5 h. (paper)

  17. Relationship Between Pretraining Subjective Wellness Measures, Player Load, and Rating-of-Perceived-Exertion Training Load in American College Football.

    Science.gov (United States)

    Govus, Andrew D; Coutts, Aaron; Duffield, Rob; Murray, Andrew; Fullagar, Hugh

    2018-01-01

    The relationship between pretraining subjective wellness and external and internal training load in American college football is unclear. To examine the relationship of pretraining subjective wellness (sleep quality, muscle soreness, energy, wellness Z score) with player load and session rating of perceived exertion (s-RPE-TL) in American college football players. Subjective wellness (measured using 5-point, Likert-scale questionnaires), external load (derived from GPS and accelerometry), and s-RPE-TL were collected during 3 typical training sessions per week for the second half of an American college football season (8 wk). The relationship of pretraining subjective wellness with player load and s-RPE training load was analyzed using linear mixed models with a random intercept for athlete and a random slope for training session. Standardized mean differences (SMDs) denote the effect magnitude. A 1-unit increase in wellness Z score and energy was associated with trivial 2.3% (90% confidence interval [CI] 0.5, 4.2; SMD 0.12) and 2.6% (90% CI 0.1, 5.2; SMD 0.13) increases in player load, respectively. A 1-unit increase in muscle soreness (players felt less sore) corresponded to a trivial 4.4% (90% CI -8.4, -0.3; SMD -0.05) decrease in s-RPE training load. Measuring pretraining subjective wellness may provide information about players' capacity to perform in a training session and could be a key determinant of their response to the imposed training demands American college football. Hence, monitoring subjective wellness may aid in the individualization of training prescription in American college football players.

  18. Role of Marangoni stress during breakup of surfactant-covered liquid threads: Reduced rates of thinning and microthread cascades

    Science.gov (United States)

    Kamat, Pritish M.; Wagoner, Brayden W.; Thete, Sumeet S.; Basaran, Osman A.

    2018-04-01

    Adsorption onto and lowering of surface tension σ of fluid interfaces by surfactants is exploited in drop formation (e.g., inkjet printing) where a thinning liquid thread (radius h ) connects an about-to-form drop to the liquid that remains hanging from the nozzle when the former falls from it. Surfactants can affect thread pinch-off in two ways: first, by lowering σ , they lower capillary pressure (σ /h ), and second, as surfactant concentration along the interface can be nonuniform, they cause the interface to be subjected to a surface tension gradient or Marangoni stress. Recent studies show that the location where the thread breaks is devoid of surfactant, and others assert that the influence of Marangoni stress on pinch-off is negligible. We demonstrate by simulations and experiments that surfactants play a major role in drop formation and that Marangoni stresses acting near but not at the pinch point give rise to reduced rates of thread thinning and formation of multiple microthreads that distinguish pinch-off of surfactant-covered threads from surfactant-free ones. Thinning at finite Reynolds and Peclet numbers, Re and Pe, is shown to exhibit intermediate scaling regimes that have heretofore only been observed during pinch-off of threads undergoing creeping flow (Re=0 ) while convection of surfactant is weak compared to its diffusion (Pe<1 ).

  19. The impact of long-term water stress on relative growth rate and morphology of needles and shoots of Metasequoia glyptostroboides seedlings: research toward identifying mechanistic models.

    Science.gov (United States)

    Zhang, Yanxiang; Equiza, Maria Alejandra; Zheng, Quanshui; Tyree, Melvin T

    2011-09-01

    Leaf morphology in the upper canopy of trees tends to be different from that lower down. The effect of long-term water stress on leaf growth and morphology was studied in seedlings of Metasequoia glyptostroboides to understand how tree height might affect leaf morphology in larger trees. Tree height increases water stress on growing leaves through increased hydraulic resistance to water flow and increased gravitational potential, hence we assume that water stress imposed by soil dehydration will have an effect equivalent to stress induced by height. Seedlings were subjected to well-watered and two constant levels of long-term water stress treatments. Drought treatment significantly reduced final needle count, area and mass per area (leaf mass area, LMA) and increased needle density. Needles from water-stressed plants had lower maximum volumetric elastic modulus (ε(max)), osmotic potential at full turgor (Ψ¹⁰⁰(π)) (and at zero turgor (Ψ⁰(π)) (than those from well-watered plants. Palisade and spongy mesophyll cell size and upper epidermal cell size decreased significantly in drought treatments. Needle relative growth rate, needle length and cell sizes were linear functions of the daily average water potential at the time of leaf growth (r² 0.88-0.999). We conclude that water stress alone does mimic the direction and magnitude of changes in leaf morphology observed in tall trees. The results are discussed in terms of various models for leaf growth rate. Copyright © Physiologia Plantarum 2011.

  20. Conflicting deductions from machining and other tests, concerning flow stress at high strain rates and temperatures

    International Nuclear Information System (INIS)

    Childs, T.H.C.

    1974-01-01

    This paper is concerned with the friction interaction between an En1A chip and a cemented tungsten--titanium carbide cutting tool during turning En1A on a lathe at speeds between 0.25 and 7.5 m s -1 and at feeds of 0.13 and 0.26 mm rev -1 . The mean friction stress has been measured and deductions made from chip shape measurements about the variation of the friction stress over the rake face. Three regimes of continuous chip formation were seen. In the first, the mean friction stress was independent of strain rate and temperature, in the second it depended on temperature and in the third, at the highest cutting speeds, it depended on temperature and feed. In the third regime, softening of the chip material caused by frictional heating limited the friction force, but the softening temperature depended on the heating rate of the chip material. Softening occurred at 700 0 C when the rate of heating from room temperature was 5.4 x 10 5 0 C s -1 and at 1160 0 C when the rate was 1.7 x 10 7 0 C s -1 . (U.S.)

  1. Heart Rate, Stress, and Occupational Noise Exposure among Electronic Waste Recycling Workers

    Directory of Open Access Journals (Sweden)

    Katrina N. Burns

    2016-01-01

    Full Text Available Electronic waste (e-waste is a growing occupational and environmental health issue around the globe. E-waste recycling is a green industry of emerging importance, especially in low-and middle-income countries where much of this recycling work is performed, and where many people’s livelihoods depend on this work. The occupational health hazards of e-waste recycling have not been adequately explored. We performed a cross-sectional study of noise exposures, heart rate, and perceived stress among e-waste recycling workers at a large e-waste site in Accra, Ghana. We interviewed 57 workers and continuously monitored their individual noise exposures and heart rates for up to 24 h. More than 40% of workers had noise exposures that exceeded recommended occupational (85 dBA and community (70 dBA noise exposure limits, and self-reported hearing difficulties were common. Workers also had moderate to high levels of perceived stress as measured via Cohen’s Perceived Stress Scale, and reported a variety of symptoms that could indicate cardiovascular disease. Noise exposures were moderately and significantly correlated with heart rate (Spearman’s ρ 0.46, p < 0.001. A mixed effects linear regression model indicated that a 1 dB increase in noise exposure was associated with a 0.17 increase in heart rate (p-value = 0.01 even after controlling for work activities, age, smoking, perceived stress, and unfavorable physical working conditions. These findings suggest that occupational and non-occupational noise exposure is associated with elevations in average heart rate, which may in turn predict potential cardiovascular damage.

  2. Rate of rise in diastolic blood pressure influences vascular sympathetic response to mental stress.

    Science.gov (United States)

    El Sayed, Khadigeh; Macefield, Vaughan G; Hissen, Sarah L; Joyner, Michael J; Taylor, Chloe E

    2016-12-15

    Research indicates that individuals may experience a rise (positive responders) or fall (negative responders) in muscle sympathetic nerve activity (MSNA) during mental stress. In this study, we examined the early blood pressure responses (including the peak, time of peak and rate of rise in blood pressure) to mental stress in positive and negative responders. Negative MSNA responders to mental stress exhibit a more rapid rise in diastolic pressure at the onset of the stressor, suggesting a baroreflex-mediated suppression of MSNA. In positive responders there is a more sluggish rise in blood pressure during mental stress, which appears to be MSNA-driven. This study suggests that whether MSNA has a role in the pressor response is dependent upon the reactivity of blood pressure early in the task. Research indicates that individuals may experience a rise (positive responders) or fall (negative responders) in muscle sympathetic nerve activity (MSNA) during mental stress. The aim was to examine the early blood pressure response to stress in positive and negative responders and thus its influence on the direction of change in MSNA. Blood pressure and MSNA were recorded continuously in 21 healthy young males during 2 min mental stressors (mental arithmetic, Stroop test) and physical stressors (cold pressor, handgrip exercise, post-exercise ischaemia). Participants were classified as negative or positive responders according to the direction of the mean change in MSNA during the stressor tasks. The peak changes, time of peak and rate of changes in blood pressure were compared between groups. During mental arithmetic negative responders experienced a significantly greater rate of rise in diastolic blood pressure in the first minute of the task (1.3 ± 0.5 mmHg s -1 ) compared with positive responders (0.4 ± 0.1 mmHg s -1 ; P = 0.03). Similar results were found for the Stroop test. Physical tasks elicited robust parallel increases in blood pressure and MSNA across

  3. A thin rivulet or ridge subject to a uniform transverse shear stress at its free surface due to an external airflow

    KAUST Repository

    Sullivan, J. M.; Paterson, C.; Wilson, S. K.; Duffy, B. R.

    2012-01-01

    We use the lubrication approximation to analyze three closely related problems involving a thin rivulet or ridge (i.e., a two-dimensional droplet) of fluid subject to a prescribed uniform transverse shear stress at its free surface due

  4. Perceived social stress, pregnancy-related anxiety, depression and subjective social status among pregnant Mexican and Mexican American women in south Texas.

    Science.gov (United States)

    Fleuriet, K Jill; Sunil, T S

    2014-05-01

    The purpose of this study was to determine differences in subjective social status, perceived social stress, depressive symptoms, and pregnancy-related anxiety between pregnant Mexican American and Mexican immigrant women. Three hundred pregnant Mexican immigrant and Mexican American women in South Texas were surveyed for pregnancy-related anxiety, perceived social stress, depressive symptoms, and subjective social status. Pregnant Mexican immigrant women had higher levels of pregnancy-related anxiety and lower levels of depression and perceived social stress than pregnant Mexican American women. Change in these variables among Mexican immigrant women was relatively linear as time of residence in the United States increased. Mexican immigrant and Mexican American women had significantly different correlations between subjective social status, self-esteem and perceived social stress. Results indicate that subjective social status is an important psychosocial variable among pregnant Hispanic women. Results contribute to ongoing efforts to provide culturally responsive prenatal psychosocial support services.

  5. Growth rate regulated genes and their wide involvement in the Lactococcus lactis stress responses

    Directory of Open Access Journals (Sweden)

    Redon Emma

    2008-07-01

    Full Text Available Abstract Background The development of transcriptomic tools has allowed exhaustive description of stress responses. These responses always superimpose a general response associated to growth rate decrease and a specific one corresponding to the stress. The exclusive growth rate response can be achieved through chemostat cultivation, enabling all parameters to remain constant except the growth rate. Results We analysed metabolic and transcriptomic responses of Lactococcus lactis in continuous cultures at different growth rates ranging from 0.09 to 0.47 h-1. Growth rate was conditioned by isoleucine supply. Although carbon metabolism was constant and homolactic, a widespread transcriptomic response involving 30% of the genome was observed. The expression of genes encoding physiological functions associated with biogenesis increased with growth rate (transcription, translation, fatty acid and phospholipids metabolism. Many phages, prophages and transposon related genes were down regulated as growth rate increased. The growth rate response was compared to carbon and amino-acid starvation transcriptomic responses, revealing constant and significant involvement of growth rate regulations in these two stressful conditions (overlap 27%. Two regulators potentially involved in the growth rate regulations, llrE and yabB, have been identified. Moreover it was established that genes positively regulated by growth rate are preferentially located in the vicinity of replication origin while those negatively regulated are mainly encountered at the opposite, thus indicating the relationship between genes expression and their location on chromosome. Although stringent response mechanism is considered as the one governing growth deceleration in bacteria, the rigorous comparison of the two transcriptomic responses clearly indicated the mechanisms are distinct. Conclusion This work of integrative biology was performed at the global level using transcriptomic analysis

  6. Heart Rate Variability as an Indicator of Chronic Stress Caused by Lameness in Dairy Cows.

    Directory of Open Access Journals (Sweden)

    Levente Kovács

    Full Text Available Most experimental studies on animal stress physiology have focused on acute stress, while chronic stress, which is also encountered in intensive dairy cattle farming--e.g. in case of lameness--, has received little attention. We investigated heart rate (HR and heart rate variability (HRV as indicators of the autonomic nervous system activity and fecal glucocorticoid concentrations as the indicator of the hypothalamic-pituitary-adrenal axis activity in lame (with locomotion scores 4 and 5; n = 51 and non-lame (with locomotion scores 1 and 2; n = 52 Holstein-Friesian cows. Data recorded during the periods of undisturbed lying--representing baseline cardiac activity--were involved in the analysis. Besides linear analysis methods of the cardiac inter-beat interval (time-domain geometric, frequency domain and Poincaré analyses non-linear HRV parameters were also evaluated. With the exception of standard deviation 1 (SD1, all HRV indices were affected by lameness. Heart rate was lower in lame cows than in non-lame ones. Vagal tone parameters were higher in lame cows than in non-lame animals, while indices of the sympathovagal balance reflected on a decreased sympathetic activity in lame cows. All geometric and non-linear HRV measures were lower in lame cows compared to non-lame ones suggesting that chronic stress influenced linear and non-linear characteristics of cardiac function. Lameness had no effect on fecal glucocorticoid concentrations. Our results demonstrate that HRV analysis is a reliable method in the assessment of chronic stress, however, it requires further studies to fully understand the elevated parasympathetic and decreased sympathetic tone in lame animals.

  7. Heart Rate Variability Frequency Domain Alterations among Healthy Nurses Exposed to Prolonged Work Stress

    Directory of Open Access Journals (Sweden)

    Rossana Borchini

    2018-01-01

    Full Text Available The deregulation of the autonomic nervous system assessed through the heart rate variability (HRV analysis is a promising pathway linking work stress and cardiovascular diseases. We aim to investigate the associations between HRV High Frequency (HF and Low Frequency (LF powers and work stress in a sample of 36 healthy nurses. Perceived work stress was assessed twice one year apart, using the Job Content and Effort Reward Imbalance questionnaires. This allows to classify nurses in three exposure groups: “prolonged high stress” (PHS, “recent high stress” (RHS and “stable low stress” (SLS. A 24-h ECG monitoring was later performed during a working day (WD and a subsequent resting day (RD. Statistically significantly lower (p < 0.02 HF and LF means were found in PHS and RHS nurses during the working periods. In the subsequent resting periods, HF means showed increases over time in the RHS (beta = +0.41, p < 0.05, but not in PHS nurses. LF means did not show any substantial increases in the resting periods, in the PHS group with geometric means lower when compared to SLS, in the non-working and resting periods. Our study evidences that both prolonged and recent perceived high work stress were associated with a reduction of HF and LF powers during work. In addition, prolonged stress was associated with a lack of recovery during not-working and resting periods.

  8. Genetic component of sensitivity to heat stress for nonreturn rate of Brazilian Holstein cattle.

    Science.gov (United States)

    Santana, M L; Bignardi, A B; Stefani, G; El Faro, L

    2017-08-01

    The objectives of the present study were: 1) to investigate variation in the genetic component of heat stress for nonreturn rate at 56 days after first artificial insemination (NR56); 2) to identify and characterize the genotype by environment interaction (G × E) due to heat stress for NR56 of Brazilian Holstein cattle. A linear random regression model (reaction norm model) was applied to 51,748 NR56 records of 28,595 heifers and multiparous cows. The decline in NR56 due to heat stress was more pronounced in milking cows compared to heifers. The age of females at first artificial insemination and temperature-humidity index (THI) exerted an important influence on the genetic parameters of NR56. Several evidence of G × E on NR56 were found as the high slope/intercept ratio and frequent intersection of reaction norms. Additionally, the genetic correlation between NR56 at opposite extremes of the THI scale reached estimates below zero, indicating that few of the same genes are responsible for NR56 under conditions of thermoneutrality and heat stress. The genetic evaluation and selection for NR56 in Holstein cattle reared under (sub)tropical conditions should therefore take into consideration the genetic variation on age at insemination and G × E due to heat stress. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. The effect of heart rate variability biofeedback training on stress and anxiety: a meta-analysis.

    Science.gov (United States)

    Goessl, V C; Curtiss, J E; Hofmann, S G

    2017-11-01

    Some evidence suggests that heart rate variability (HRV) biofeedback might be an effective way to treat anxiety and stress symptoms. To examine the effect of HRV biofeedback on symptoms of anxiety and stress, we conducted a meta-analysis of studies extracted from PubMed, PsycINFO and the Cochrane Library. The search identified 24 studies totaling 484 participants who received HRV biofeedback training for stress and anxiety. We conducted a random-effects meta-analysis. The pre-post within-group effect size (Hedges' g) was 0.81. The between-groups analysis comparing biofeedback to a control condition yielded Hedges' g = 0.83. Moderator analyses revealed that treatment efficacy was not moderated by study year, risk of study bias, percentage of females, number of sessions, or presence of an anxiety disorder. HRV biofeedback training is associated with a large reduction in self-reported stress and anxiety. Although more well-controlled studies are needed, this intervention offers a promising approach for treating stress and anxiety with wearable devices.

  10. Effect of body composition, aerobic performance and physical activity on exercise-induced oxidative stress in healthy subjects.

    Science.gov (United States)

    Więcek, Magdalena; Maciejczyk, Marcin; Szymura, Jadwiga; Wiecha, Szczepan; Kantorowicz, Malgorzata; Szygula, Zbigniew

    2017-01-01

    Oxidative stress could be the result of an increase in ATP resynthesis during exercise. The aim of the study was to compare prooxidant-antioxidant balance (PAB) disturbances induced by exercise at maximal intensity in young men with differing body compositions. Thirty-nine subjects were selected from 1549 volunteers aged 18-30, based on lean body mass (LBM) and body fat percentage (%BF), and then assigned into one of the following groups: control group (CON), including subjects with average LBM (59.0-64.3 kg) and average %BF (14.0-18.5%); high body fat (HBF) group, including subjects with high %BF (>21.5%) and average LBM; and high lean body mass (HLBM) group, including subjects with high LBM (>66.3 kg) and average %BF. Participants' physical activity was determined. A running test with a gradually increased load was used. Before and 3 minutes after exercise, total oxidative status (TOS) and total antioxidant capacity (TAC) were determined in the plasma, and the Oxidative Stress Index (OSI = TOS/TAC) was calculated. Maximal oxygen uptake (VO2max) was comparable in the HBF and HLBM groups (53.12±1.51 mL/kg and 50.25±1.27 mL/kg, respectively) and significantly lower compared to the CON group (58.23±1.62 mL/kg). The CON, HBF and HLBM groups showed similar significant (P0.05). There was significant negative correlation between OSI, measured before and after exercise, and participants' physical activity. There was no correlation between OSI and VO2max, BM, LBM, %BF and BMI. Exercise at maximal intensity causes a similar increase in TOS and in TAC in subjects with increased %BF and elevated content of LBM and regardless of body composition, the ratios of TOS/TAC concentrations before and after maximal-intensity exercise, have lower values in people with higher physical activity levels and are not dependent on aerobic performance (VO2max).

  11. An examination of personality, emotional intelligence, coping, gender and subjective well-being with perceived stress (trait and state) in undergraduate students.

    OpenAIRE

    Osborne, Shona Elizabeth

    2009-01-01

    This multivariate study aimed to further understand student stress. Associations between personality, emotional intelligence, coping and subjective well-being with perceived stress (trait and state) were examined in 238 undergraduate students, using self-report measures. Gender differences in these variables were also investigated. The results showed that students low in emotional stability, extraversion, emotional intelligence, subjective well-being and those with a tendency to use emotion...

  12. Genomic study and Medical Subject Headings enrichment analysis of early pregnancy rate and antral follicle numbers in Nelore heifers

    DEFF Research Database (Denmark)

    Oliveira Junior, G. A.; Perez, B. C.; Cole, J. B.

    2017-01-01

    be considered in a functional enrichment analysis to identify biological mechanisms involved in fertility. Medical Subject Headings (MeSH) were detected using the MESHR package, allowing the extraction of broad meanings from the gene lists provided by the GWAS. The estimated heritability for HP was 0.28 +/- 0...... gains. In this study, we performed a genomewide association study (GWAS) to identify genetic variants associated with reproductive traits in Nelore beef cattle. Heifer pregnancy (HP) was recorded for 1,267 genotyped animals distributed in 12 contemporary groups (CG) with an average pregnancy rate of 0...

  13. A test case of the deformation rate analysis (DRA) stress measurement method

    Energy Technology Data Exchange (ETDEWEB)

    Dight, P.; Hsieh, A. [Australian Centre for Geomechanics, Univ. of WA, Crawley (Australia); Johansson, E. [Saanio and Riekkola Oy, Helsinki (Finland); Hudson, J.A. [Rock Engineering Consultants (United Kingdom); Kemppainen, K.

    2012-01-15

    As part of Posiva's site and ONKALO investigations, the in situ rock stress has been measured by a variety of techniques, including hydraulic fracturing, overcoring, and convergence measurements. All these techniques involve direct measurements in a drillhole or at the rock surface. An alternative method is to test drillhole core in a way that enables estimation of the magnitudes and orientations of the in situ rock stress. The Kaiser Effect (KE) and Deformation Rate Analysis (DRA) are two ways to do this. In the work reported here, a 'blind' DRA test was conducted on core obtained from the POSE (Posiva's Olkiluoto Spalling Experiment) niche in the ONKALO. The term 'blind' means that the two first authors of this report, who conducted the tests at the Australian Centre for Geomechanics, did not know the depths below surface at which the cores had been obtained. The results of this DRA Test Case are presented, together with an explanation of the DRA procedure. Also, additional information that would help in such DRA testing and associated analysis is explained. One of the problems in comparing the DRA results with the known Olkiluoto stress field is that the latter is highly variable across the site, as experienced by the previous in situ stress measurements and as predicted by numerical analysis. The variability is mainly caused by the presence of the large brittle deformation zones which perturb the local stress state. However, this variability reduces with depth and the stress field becomes more stable at the {approx} 350 m at which the drillhole cores were obtained. Another compounding difficulty is that the stress quantity, being a second order tensor, requires six independent components for its specification. In other words, comparison of the DRA results and the known stress field requires comparison of six different quantities. In terms of the major principal stress orientation, the DRA results predict an orientation completely

  14. A test case of the deformation rate analysis (DRA) stress measurement method

    International Nuclear Information System (INIS)

    Dight, P.; Hsieh, A.; Johansson, E.; Hudson, J.A.; Kemppainen, K.

    2012-01-01

    As part of Posiva's site and ONKALO investigations, the in situ rock stress has been measured by a variety of techniques, including hydraulic fracturing, overcoring, and convergence measurements. All these techniques involve direct measurements in a drillhole or at the rock surface. An alternative method is to test drillhole core in a way that enables estimation of the magnitudes and orientations of the in situ rock stress. The Kaiser Effect (KE) and Deformation Rate Analysis (DRA) are two ways to do this. In the work reported here, a 'blind' DRA test was conducted on core obtained from the POSE (Posiva's Olkiluoto Spalling Experiment) niche in the ONKALO. The term 'blind' means that the two first authors of this report, who conducted the tests at the Australian Centre for Geomechanics, did not know the depths below surface at which the cores had been obtained. The results of this DRA Test Case are presented, together with an explanation of the DRA procedure. Also, additional information that would help in such DRA testing and associated analysis is explained. One of the problems in comparing the DRA results with the known Olkiluoto stress field is that the latter is highly variable across the site, as experienced by the previous in situ stress measurements and as predicted by numerical analysis. The variability is mainly caused by the presence of the large brittle deformation zones which perturb the local stress state. However, this variability reduces with depth and the stress field becomes more stable at the ∼ 350 m at which the drillhole cores were obtained. Another compounding difficulty is that the stress quantity, being a second order tensor, requires six independent components for its specification. In other words, comparison of the DRA results and the known stress field requires comparison of six different quantities. In terms of the major principal stress orientation, the DRA results predict an orientation completely different to the NW-SE regional

  15. The biologic effects of grounding the human body during sleep as measured by cortisol levels and subjective reporting of sleep, pain, and stress.

    Science.gov (United States)

    Ghaly, Maurice; Teplitz, Dale

    2004-10-01

    Diurnal cortisol secretion levels were measured and circadian cortisol profiles were evaluated in a pilot study conducted to test the hypothesis that grounding the human body to earth during sleep will result in quantifiable changes in cortisol. It was also hypothesized that grounding the human body would result in changes in sleep, pain, and stress (anxiety, depression, irritability), as measured by subjective reporting. Twelve (12) subjects with complaints of sleep dysfunction, pain, and stress were grounded to earth during sleep for 8 weeks in their own beds using a conductive mattress pad. Saliva tests were administered to establish pregrounding baseline cortisol levels. Levels were obtained at 4-hour intervals for a 24-hour period to determine the circadian cortisol profile. Cortisol testing was repeated at week 6. Subjective symptoms of sleep dysfunction, pain, and stress were reported daily throughout the 8-week test period. Measurable improvements in diurnal cortisol profiles were observed, with cortisol levels significantly reduced during night-time sleep. Subjects' 24-hour circadian cortisol profiles showed a trend toward normalization. Subjectively reported symptoms, including sleep dysfunction, pain, and stress, were reduced or eliminated in nearly all subjects. Results indicate that grounding the human body to earth ("earthing") during sleep reduces night-time levels of cortisol and resynchronizes cortisol hormone secretion more in alignment with the natural 24-hour circadian rhythm profile. Changes were most apparent in females. Furthermore, subjective reporting indicates that grounding the human body to earth during sleep improves sleep and reduces pain and stress.

  16. [Motivation effect on EEG spectral power and heart rate parameters in students during examination stress].

    Science.gov (United States)

    Dzhebrailova, T D; Korobeĭnikova, I I; Rudneva, L P

    2014-09-01

    EEG spectral power was calculated in 24 students (18-21 years) with different levels of motivation and anxiety (tested by Spielberger) in two experimental conditions: during the common educational process and the examination stress. Before examination tests, in subjects with high motivation and anxiety level the relative delta activity power increased in right frontal (F4) brain areas. In students with medium motivation immediately before an examination the relative beta2-activity power increased in right frontal (F4) brain areas. It is suggested that delta oscillati- ons reflect activity of the defensive motivational system, whereas beta2 oscillations may be associated with the achievement motivation.

  17. Relationship between Autonomic Markers of Heart Rate and Subjective Indicators of Recovery Status in Male, Elite Badminton Players

    Directory of Open Access Journals (Sweden)

    Christo A. Bisschoff, Ben Coetzee, Michael R. Esco

    2016-12-01

    Full Text Available The primary aim of the study was to determine if heart rate variability (HRV, and heart rate recovery (HRR are related to several subjective indicators of recovery status (muscle soreness, hydration status, sleep quality and quantity as well as pre-competition mood states for different match periods in male, elite, African, singles badminton players. HRV and HRR were measured in twenty-two badminton players before (pre-match, during (in-match, after (post-match and during rest periods (in-match rest of 46 national and international matches. Muscle soreness, hydration status, and sleep quality and quantity were measured on a daily basis whereas mood states were measured just before each match via questionnaires. Prior to each match warm-up, players were fitted with a Fix Polar Heart Rate Transmitter Belt to record heart rate every second during each match and HRR during service breaks and after matches. Kubios HRV software was used for final HRV analyses from the series of R-R-intervals. A strong, significant canonical correlation (Rc = 0.96, p = 0.014 was found between HRV, HRR and subjective indicators of recovery status for the in-match period, but only strong, non-significant relationships were observed for pre-match (Rc = 0.98, p = 0.626 and post-match periods (Rc = 0.98, p = 0.085 and a low non-significant relationship (Rc = 0.69, p = 0.258 for the in-match rest period. Canonical functions accounted for between 47.89% and 96.43% of the total variation between the two canonical variants. Results further revealed that Ln-HFnu, the energy index and vigour were the most prominent variables in the relationship between the autonomic markers of heart rate and recovery-related variables. In conclusion, this study proved that subjective indicators of recovery status influence HRV and HRR measures obtained in a competitive badminton environment and should therefore be incorporated in protocols that evaluate these ANS-related parameters.

  18. Relationship between Autonomic Markers of Heart Rate and Subjective Indicators of Recovery Status in Male, Elite Badminton Players.

    Science.gov (United States)

    Bisschoff, Christo A; Coetzee, Ben; Esco, Michael R

    2016-12-01

    The primary aim of the study was to determine if heart rate variability (HRV), and heart rate recovery (HRR) are related to several subjective indicators of recovery status (muscle soreness, hydration status, sleep quality and quantity as well as pre-competition mood states) for different match periods in male, elite, African, singles badminton players. HRV and HRR were measured in twenty-two badminton players before (pre-match), during (in-match), after (post-match) and during rest periods (in-match rest) of 46 national and international matches. Muscle soreness, hydration status, and sleep quality and quantity were measured on a daily basis whereas mood states were measured just before each match via questionnaires. Prior to each match warm-up, players were fitted with a Fix Polar Heart Rate Transmitter Belt to record heart rate every second during each match and HRR during service breaks and after matches. Kubios HRV software was used for final HRV analyses from the series of R-R-intervals. A strong, significant canonical correlation (Rc = 0.96, p = 0.014) was found between HRV, HRR and subjective indicators of recovery status for the in-match period, but only strong, non-significant relationships were observed for pre-match (Rc = 0.98, p = 0.626) and post-match periods (Rc = 0.98, p = 0.085) and a low non-significant relationship (Rc = 0.69, p = 0.258) for the in-match rest period. Canonical functions accounted for between 47.89% and 96.43% of the total variation between the two canonical variants. Results further revealed that Ln-HFnu, the energy index and vigour were the most prominent variables in the relationship between the autonomic markers of heart rate and recovery-related variables. In conclusion, this study proved that subjective indicators of recovery status influence HRV and HRR measures obtained in a competitive badminton environment and should therefore be incorporated in protocols that evaluate these ANS-related parameters.

  19. Investigation of cytokines, oxidative stress, metabolic, and inflammatory biomarkers after orange juice consumption by normal and overweight subjects

    Directory of Open Access Journals (Sweden)

    Grace K. Z. S. Dourado

    2015-10-01

    Full Text Available Background: Abdominal adiposity has been linked to metabolic abnormalities, including dyslipidemia, oxidative stress, and low-grade inflammation. Objective: To test the hypothesis that consumption of 100% orange juice (OJ would improve metabolic, oxidative, and inflammatory biomarkers and cytokine levels in normal and overweight subjects with increased waist circumference. Design: Subjects were divided into two groups in accordance with their body mass index: normal and overweight. Both groups of individuals consumed 750 mL of OJ daily for 8 weeks. Body composition (weight, height, percentage of fat mass, and waist circumference; metabolic biomarkers (total cholesterol, low-density lipoprotein-cholesterol [LDL-C], high-density lipoprotein-cholesterol [HDL-C], triglycerides, glucose, insulin, HOMA-IR, and glycated hemoglobin; oxidative biomarkers (malondialdehyde and DPPH•; inflammatory biomarkers (high-sensitivity C-reactive protein [hsCRP]; cytokines (IL-4, IL-10, IL-12, TNF-α, and IFN-γ; and diet were evaluated before and after consumption of OJ for 8 weeks. Results: The major findings of this study were: 1 no alteration in body composition in either group; 2 improvement of the lipid profile, evidenced by a reduction in total cholesterol and LDL-C; 3 a potential stimulation of the immune response due to increase in IL-12; 4 anti-inflammatory effect as a result of a marked reduction in hsCRP; and 5 antioxidant action by the enhancement of total antioxidant capacity and the reduction of lipid peroxidation, in both normal and overweight subjects. Conclusions: OJ consumption has a positive effect on important biomarkers of health status in normal and overweight subjects, thereby supporting evidence that OJ acts as functional food and could be consumed as part of a healthy diet to prevent metabolic and chronic diseases.

  20. The very low-frequency band of heart rate variability represents the slow recovery component after a mental stress task.

    Directory of Open Access Journals (Sweden)

    Harunobu Usui

    Full Text Available The very low-frequency (VLF band of heart rate variability (HRV has different characteristics compared with other HRV components. Here we investigated differences in HRV changes after a mental stress task. After the task, the high-frequency (HF band and ratio of high- to low-frequency bands (LF/HF immediately returned to baseline. We evaluated the characteristics of VLF band changes after a mental stress task. We hypothesized that the VLF band decreases during the Stroop color word task and there would be a delayed recovery for 2 h after the task (i.e., the VLF change would exhibit a "slow recovery". Nineteen healthy, young subjects were instructed to rest for 10 min, followed by a Stroop color word task for 20 min. After the task, the subjects were instructed to rest for 120 min. For all subjects, R-R interval data were collected; analysis was performed for VLF, HF, and LF/HF ratio. HRV during the rest time and each 15-min interval of the recovery time were compared. An analysis of the covariance was performed to adjust for the HF band and LF/HF ratio as confounding variables of the VLF component. HF and VLF bands significantly decreased and the LF/HF ratio significantly increased during the task compared with those during rest time. During recovery, the VLF band was significantly decreased compared with the rest time. After the task, the HF band and LF/HF ratio immediately returned to baseline and were not significantly different from the resting values. After adjusting for HF and LF/HF ratio, the VLF band had significantly decreased compared with that during rest. The VLF band is the "slow recovery" component and the HF band and LF/HF ratio are the "quick recovery" components of HRV. This VLF characteristic may clarify the unexplained association of the VLF band in cardiovascular disease prevention.

  1. The very low-frequency band of heart rate variability represents the slow recovery component after a mental stress task.

    Science.gov (United States)

    Usui, Harunobu; Nishida, Yusuke

    2017-01-01

    The very low-frequency (VLF) band of heart rate variability (HRV) has different characteristics compared with other HRV components. Here we investigated differences in HRV changes after a mental stress task. After the task, the high-frequency (HF) band and ratio of high- to low-frequency bands (LF/HF) immediately returned to baseline. We evaluated the characteristics of VLF band changes after a mental stress task. We hypothesized that the VLF band decreases during the Stroop color word task and there would be a delayed recovery for 2 h after the task (i.e., the VLF change would exhibit a "slow recovery"). Nineteen healthy, young subjects were instructed to rest for 10 min, followed by a Stroop color word task for 20 min. After the task, the subjects were instructed to rest for 120 min. For all subjects, R-R interval data were collected; analysis was performed for VLF, HF, and LF/HF ratio. HRV during the rest time and each 15-min interval of the recovery time were compared. An analysis of the covariance was performed to adjust for the HF band and LF/HF ratio as confounding variables of the VLF component. HF and VLF bands significantly decreased and the LF/HF ratio significantly increased during the task compared with those during rest time. During recovery, the VLF band was significantly decreased compared with the rest time. After the task, the HF band and LF/HF ratio immediately returned to baseline and were not significantly different from the resting values. After adjusting for HF and LF/HF ratio, the VLF band had significantly decreased compared with that during rest. The VLF band is the "slow recovery" component and the HF band and LF/HF ratio are the "quick recovery" components of HRV. This VLF characteristic may clarify the unexplained association of the VLF band in cardiovascular disease prevention.

  2. Optimization Design of Structures Subjected to Transient Loads Using First and Second Derivatives of Dynamic Displacement and Stress

    Directory of Open Access Journals (Sweden)

    Qimao Liu

    2012-01-01

    Full Text Available This paper developed an effective optimization method, i.e., gradient-Hessian matrix-based method or second order method, of frame structures subjected to the transient loads. An algorithm of first and second derivatives of dynamic displacement and stress with respect to design variables is formulated based on the Newmark method. The inequality time-dependent constraint problem is converted into a sequence of appropriately formed time-independent unconstrained problems using the integral interior point penalty function method. The gradient and Hessian matrixes of the integral interior point penalty functions are also computed. Then the Marquardt's method is employed to solve unconstrained problems. The numerical results show that the optimal design method proposed in this paper can obtain the local optimum design of frame structures and sometimes is more efficient than the augmented Lagrange multiplier method.

  3. The differentiated assessment of damage to economy of subjects of the Siberian Federal District from road and transport accident rate

    Science.gov (United States)

    Petrov, Artur I.; Svistunova, Vera A.; Petrova, Daria A.

    2018-01-01

    The results of assessment of damage from the road accident rate in subjects of the Siberian Federal District (SFD) of the Russian Federation are presented in the article. The thesis about spatial differentiation of the Gross Regional Product (GRP) losses in different regions of the country because of people’s death and injuries in the road accidents (RA) and due to formations of property and ecological damage was chosen as a working hypothesis. The calculations, carried out for 12 subjects of the SFD, confirmed this idea. The range of calculated values of economic damage from road accident rate (in % of GRP) was from 1.3 (Tomsk region) to 12.6 (Republic of Tyva) in 2015. In article the attempt to explain the received result by heterogeneous development of economics in various Russian regions is made. The consequence of it is a heterogeneous quality of people’s life and quite various perception of life value by inhabitants of different regions that influences their life safety level.

  4. [Primary study on characteristics of insulin secretion rate, metabolic clearance rate and sensitivity in non-insulin-dependent diabetic subjects from multiplex diabetic pedigrees].

    Science.gov (United States)

    Ran, J; Cheng, H; Li, F

    2000-01-01

    To investigate the characteristics of insulin secretion rate (ISR), metabolic clearance rate (MCR-I) and sensitivity and to explore their relationship with obesity in non-insulin-dependent diabetic subjects from multiplex diabetic pedigrees (MDP). Fifteen subjects with normal glucose tolerance and 11 non-insulin-dependent diabetic patients from MDP were included in the study. Frequently sampled intravenous glucose tolerance test (FSIVGTT) was performed. Glucose, insulin (INS) and connecting-peptide (C-P) concentrations were measured. A computer procedure devised by our laboratory was used to calculate the value of ISR at each time point, then MCR-I was acquired. Insulin sensitivity index (SI) was calculated according to minimal model technique about glucose in FSIVGTT. The ISR curve in control group was biphasic, while in non-insulin. In non-insulin-dependent diabetic group, areas under the curves of C-P (AUCC) and ISR level (AUCS) measured during 0 approximately 16 min were 7.9 nmol.min(-1).L(-1) +/- 2.8 nmol.min(-1).L(-1), and 6.1 nmol +/- 2.2 nmol, respectively, which were significantly lower than those in control group 17.7 nmol.min(-1).L(-1) +/- 4.92 nmol.min(-1).L(-1) and 12.3 nmol +/- 3.9 nmol (P < 0.01). The two parameters were slightly higher than those in control group 155 nmol.min(-1).L(-1) +/- 44 nmol.min(-1).L(-1) vs 101 nmol.min(-1).L(-1) +/- 30 nmol.min(-1).L(-1) and 76 nmol +/- 26 nmol vs 54 nmol +/- 20.0 nmol (P < 0.05)measured during 16 approximately 180 min. There was no significant difference, between the two groups about the amount of insulin secretion during 3 hours (82 nmol +/- 28nmol vs 68 nmol +/- 21 nmol, P = 0.2). In control group, there were significant positive correlation, between AUCS, waist-hip ratio (WHR), and body surface area, (BSA) and significant negative correlation between MCR-I, SI and WHR, BSA (P < 0.01), and also between MCR-I and SI. In non-insulin-dependent diabetic group, AUCS were significantly correlated with body mass

  5. Comparative proteomic analysis of rats subjected to water immersion and restraint stress as an insight into gastric ulcers.

    Science.gov (United States)

    Zhou, Zheng-Rong; Huang, Pan; Song, Guang-Hao; Zhang, Zhuang; An, Ke; Lu, Han-Wen; Ju, Xiao-Li; Ding, Wei

    2017-10-01

    In the present study, comparative proteomic analysis was performed in rats subjected to water immersion‑restraint stress (WRS). A total of 26 proteins were differentially expressed and identified using matrix‑assisted laser desorption/ionization time of flight mass spectrometry. Among the 26 differentially expressed protein spots identified, 13 proteins were significantly upregulated under WRS, including pyruvate kinase and calreticulin, which may be closely associated with energy metabolism. In addition, 12 proteins were downregulated under WRS, including hemoglobin subunit β‑2 and keratin type II cytoskeletal 8, which may be important in protein metabolism and cell death. Gene Ontology analysis revealed the cellular distribution, molecular function and biological processes of the identified proteins. The mRNA levels of certain differentially expressed proteins were analyzed using fluorescence quantitative polymerase chain reaction analysis. The results of the present study aimed to offer insights into proteins, which are differentially expressed in gastric ulcers in stress, and provide theoretical evidence of a radical cure for gastric ulcers in humans.

  6. Survival and weight change among adult individuals of Periplaneta americana (Linnaeus, 1758 (Blattaria, Blattidae subject to various stress conditions

    Directory of Open Access Journals (Sweden)

    Jucelio Peter Duarte

    2015-05-01

    Full Text Available Periplaneta americana is a species of great importance to public health, since it can act as a vector of many pathogens and it reaches large populations in urban environments. This is probably due to its ability to resist starvation and desiccation. This study aimed to evaluate the effects of absence of water and food on survival and weight change among adult P. americana individuals and check whether the initial weight of individuals influences on their survival. Four groups having twenty P. americana couples were formed and subject to: I no water or food; II no food; III no water; and IV control group. Insects were isolated according to the groups, which were weighed at the beginning and end of the stress conditions. They remained under these conditions until all individuals in each test group were dead. Stress conditions caused reduction in survival time when compared to the control group. Adults with higher body mass survived longer when deprived only of food, while among those lacking water, weight had no influence on survival. Total weight loss was greater among individuals deprived of water than those deprived only of food.

  7. Survival and weight change among adult individuals of Periplaneta americana (Linnaeus, 1758 (Blattaria, Blattidae subject to various stress conditions

    Directory of Open Access Journals (Sweden)

    Jucelio Peter Duarte

    2015-03-01

    Full Text Available http://dx.doi.org/10.5007/2175-7925.2015v28n2p103 Periplaneta americana is a species of great importance to public health, since it can act as a vector of many pathogens and it reaches large populations in urban environments. This is probably due to its ability to resist starvation and desiccation. This study aimed to evaluate the effects of absence of water and food on survival and weight change among adult P. americana individuals and check whether the initial weight of individuals influences on their survival. Four groups having twenty P. americana couples were formed and subject to: I no water or food; II no food; III no water; and IV control group. Insects were isolated according to the groups, which were weighed at the beginning and end of the stress conditions. They remained under these conditions until all individuals in each test group were dead. Stress conditions caused reduction in survival time when compared to the control group. Adults with higher body mass survived longer when deprived only of food, while among those lacking water, weight had no influence on survival. Total weight loss was greater among individuals deprived of water than those deprived only of food.

  8. Parametric stress analyses for low-level liquid radwaste system piping of ITER subjected to seismic displacements

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Yoon-Suk [Department of Nuclear Engineering, Kyung Hee University, Yongin (Korea, Republic of); Oh, Chang-Kyun [Materials Engineering Department, KEPCO E& C, Yongin (Korea, Republic of); Kim, Hyun-Su, E-mail: hyunsu@kepco-enc.com [Materials Engineering Department, KEPCO E& C, Yongin (Korea, Republic of)

    2015-10-15

    The ITER project is aimed at demonstrating the feasibility of fusion as one of the possible energy options. A layout optimization is one of the design concerns for maintaining safety and reliability of the piping, because some piping penetrating the buildings is subjected to large seismic displacements. The objective of this study is to determine an optimum layout for the radioactive liquid transfer piping to withstand a given seismic displacements combined with internal pressure and thermal expansion. To do this, a series of finite element analyses were performed for various layouts. In addition, the feasibility for utilizing the double-walled structure was investigated. Analysis result shows that effects of the internal pressure and thermal expansion on the total stress are very small compared to that of the seismic displacements. Also, the stress as well as the deformation of the double-walled piping is larger than that of the single-walled piping although the difference is not big. Based on this result, an optimum configuration, a spiral along with U shape, is suggested.

  9. Grouping subjects based on conditioning criteria reveals differences in acquisition rates and in strength of conditioning-specific reflex modification.

    Science.gov (United States)

    Smith-Bell, Carrie A; Schreurs, Bernard G

    2017-11-01

    Averaging behavioral data such as the nictitating membrane response (NMR) across subjects can conceal important individual and group differences. Analyses were conducted of NMR data from rabbits that were grouped based on the point during NMR conditioning when subjects produced 8 conditioned responses (CR) in a set of 10 trials. This resulted in five groups (Early Day 1, Late Day 1, Early Day 2, Late Day 2, Early Day 3) in which group differences in CR acquisition rates were found. Percent (%) CRs were not found to increase monotonically and between-session differences in % CR were found. Conditioning-specific reflex modification (CRM) of the NMR is a type of enhanced reflexive responding of the NMR that is detected when the unconditioned stimulus (US) is presented in the absence of the conditioned stimulus (CS) following paired classical conditioning. CRM occurred in some subjects in all five groups. Subjects from both the group that was fastest and the group that was slowest to reach the learning criterion had unconditioned response (UR) topographies following NMR conditioning that strongly resembled the CR-UR response sequence elicited during NMR conditioning. This finding was most pronounced when the US duration used to assess CRM was equivalent to that used during NMR conditioning, further evidence to support the hypothesis that CRM is a CR that has generalized from the CS to the US. While grouping data based on conditioning criteria did not facilitate identifying individuals more predisposed to exhibiting CRM, strong CRM only occurred in the groups that reached the conditioning criterion the fastest. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Predicting NonInertial Effects with Algebraic Stress Models which Account for Dissipation Rate Anisotropies

    Science.gov (United States)

    Jongen, T.; Machiels, L.; Gatski, T. B.

    1997-01-01

    Three types of turbulence models which account for rotational effects in noninertial frames of reference are evaluated for the case of incompressible, fully developed rotating turbulent channel flow. The different types of models are a Coriolis-modified eddy-viscosity model, a realizable algebraic stress model, and an algebraic stress model which accounts for dissipation rate anisotropies. A direct numerical simulation of a rotating channel flow is used for the turbulent model validation. This simulation differs from previous studies in that significantly higher rotation numbers are investigated. Flows at these higher rotation numbers are characterized by a relaminarization on the cyclonic or suction side of the channel, and a linear velocity profile on the anticyclonic or pressure side of the channel. The predictive performance of the three types of models are examined in detail, and formulation deficiencies are identified which cause poor predictive performance for some of the models. Criteria are identified which allow for accurate prediction of such flows by algebraic stress models and their corresponding Reynolds stress formulations.

  11. Heart rate and blood pressure interactions during attempts to consciously raise or lower heart rate and blood pressure in normotensive subjects

    International Nuclear Information System (INIS)

    Lowdon, Peter; Murray, Alan; Langley, Philip

    2011-01-01

    This study investigated the interaction between heart rate (HR) and blood pressure (BP) during conscious control under visual biofeedback and background noise conditions. Normotensive volunteers were instructed to (i) decrease and (ii) increase HR (group A, n = 16) or BP (group B, n = 16). After instructions to lower HR or BP there was no significant change in HR or BP for either group. After instructions to raise HR, HR increased significantly (13.8 ± 1.3 beats min −1 , P < 0.0001) and BP did not change. However, following instructions to raise BP, both HR and BP increased significantly: systolic BP (5.2 ± 1.5 mmHg, P < 0.001), diastolic BP (3.5 ± 0.9 mmHg, P < 0.001) and HR (8.6 ± 1.3 beats min −1 , P < 0.0001). Biofeedback and background noise did not alter the relative change in HR or BP. In conclusion, normotensive subjects were unable to reduce BP or HR under conscious control. Subjects were able to increase both HR and BP, and voluntary increases in HR did not alter BP, while voluntary increases in BP also increased HR indicating distinct HR/BP interactions during conscious control

  12. Vaccination against hepatitis A and B in persons subject to homelessness in inner Sydney: vaccine acceptance, completion rates and immunogenicity.

    Science.gov (United States)

    Poulos, Roslyn G; Ferson, Mark J; Orr, Karen J; McCarthy, Michele A; Botham, Susan J; Stern, Jerome M; Lucey, Adrienne

    2010-04-01

    To determine acceptance, completion rates and immunogenicity of the standard vaccination schedule for hepatitis A (HAV) and B (HBV) in persons subject to homelessness. A convenience sample of clients (n=201) attending a medical clinic for homeless and disadvantaged persons in Sydney was enrolled. Serological screening for HAV and HBV was undertaken. An appropriate vaccination program was instituted. Post-vaccination serology determined serological response. Although many clients had serological evidence of past infection, at least 138 (69%) clients had the potential to benefit from vaccination. For hepatitis A and B vaccinations, completion rates were 73% (73 of 100 clients) and 75% (69 of 92 clients), respectively; after vaccination, protective antibody was found in 98.2% (56 of 57) and 72% (36 of 50) of clients, respectively. A successful vaccination program can be mounted with a vulnerable population. We consider a clinic with a well-established history of acceptance and utilisation by the target group; a low staff turnover and regular clientele; inclusion of vaccination as part of routine client care; and counselling (part of pre- and post-serological testing) essential components in achieving good vaccination completion rates. © 2010 The Authors. Journal Compilation © 2010 Public Health Association of Australia.

  13. Stress relaxation of entangled polystyrene solution after constant-rate, uniaxial elongation

    DEFF Research Database (Denmark)

    Matsumiya, Yumi; Masubuchi, Yuichi; Watanabe, Hiroshi

    For an entangled solution of linear polystyrene (PS 545k; M = 545k) in dibutyl phthalate (DBP), the stress relaxation after constant-rate uniaxial elongation was examined with an extensional viscosity fixture mounted on ARES (TA Instruments). The PS concentration, c = 52 wt%, was chosen in a way...... that the entanglement density M/Me of the solution coincided with that of PS 290k melt (M = 290k). After the elongation at the Rouse-based Weissenberg number Wi(R) ~ 3 up to the Hencky strain of 3, the short time stress relaxation of the solution was accelerated by a factor of ~4, which was less significant compared...... and the lack of monotonic thinning observed for the semidilute solutions. Results for less concentrated solutions will be also presented on site....

  14. Fatty acids from high rate algal pond's microalgal biomass and osmotic stress effects.

    Science.gov (United States)

    Drira, Neila; Dhouibi, Nedra; Hammami, Saoussen; Piras, Alessandra; Rosa, Antonella; Porcedda, Silvia; Dhaouadi, Hatem

    2017-11-01

    The extraction of oil from a wild microalgae biomass collected from a domestic wastewater treatment facility's high rate algal pond (HRAP) was investigated. An experiment plan was used to determine the most efficient extraction method, the optimal temperature, time and solvent system based on total lipids yield. Microwave-assisted extraction was the most efficient method whether in n-hexane or in a mixture of chloroform/methanol compared to Soxhlet, homogenization, and ultrasounds assisted extractions. This same wild biomass was cultivated in a photobioreactor (PBR) and the effect of osmotic stress was studied. The lipids extraction yield after 3days of stress increased by more than four folds without any significant loss of biomass, however, the quality of extracted total lipids in terms of saturated, monounsaturated and polyunsaturated fatty acids was not affected by salinity change in the culture medium. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Strain-rate effect on initial crush stress of irregular honeycomb under dynamic loading and its deformation mechanism

    Science.gov (United States)

    Wang, Peng; Zheng, Zhijun; Liao, Shenfei; Yu, Jilin

    2018-02-01

    The seemingly contradictory understandings of the initial crush stress of cellular materials under dynamic loadings exist in the literature, and a comprehensive analysis of this issue is carried out with using direct information of local stress and strain. Local stress/strain calculation methods are applied to determine the initial crush stresses and the strain rates at initial crush from a cell-based finite element model of irregular honeycomb under dynamic loadings. The initial crush stress under constant-velocity compression is identical to the quasi-static one, but less than the one under direct impact, i.e. the initial crush stresses under different dynamic loadings could be very different even though there is no strain-rate effect of matrix material. A power-law relation between the initial crush stress and the strain rate is explored to describe the strain-rate effect on the initial crush stress of irregular honeycomb when the local strain rate exceeds a critical value, below which there is no strain-rate effect of irregular honeycomb. Deformation mechanisms of the initial crush behavior under dynamic loadings are also explored. The deformation modes of the initial crush region in the front of plastic compaction wave are different under different dynamic loadings.

  16. Rate of fatigue crack growth in residual stress fields of welded titanium joints with different contents of embrittling impurities

    International Nuclear Information System (INIS)

    Troshchenko, V.T.; Pokrovskij, V.V.; Yarusevich, V.L.; Mikhajlov, V.I.; Sher, V.A.

    1990-01-01

    Resistance to fatigue crack growth (FCG) has been studied in welded joints of structural titanium alloys contaminated by embrittling impurities. Besides, effect of crack closing has been taken into account what makes it possible to determine the effective coefficient of the stress intensity. The rate of fatigue crack growth is proved to considerably depend on the value and direction of residual stresses. The rate dependence of FCG in welded joints of structural titanium alloys on the swing of effective coefficient of stress intensity is invariant to the value and direction of weld residual stresses

  17. Quantitation of stress echocardiography by tissue Doppler and strain rate imaging: a dream come true?

    Science.gov (United States)

    Galderisi, Maurizio; Mele, Donato; Marino, Paolo Nicola

    2005-01-01

    Tissue Doppler (TD) is an ultrasound tool providing a quantitative agreement of left ventricular regional myocardial function in different modalities. Spectral pulsed wave (PW) TD, performed online during the examination, measures instantaneous myocardial velocities. By means of color TD, velocity images are digitally stored for subsequent off-line analysis and mean myocardial velocities are measured. An implementation of color TD includes strain rate imaging (SRI), based on post-processing conversion of regional velocities in local myocardial deformation rate (strain rate) and percent deformation (strain). These three modalities have been applied to stress echocardiography for quantitative evaluation of regional left ventricular function and detection of ischemia and viability. They present advantages and limitations. PWTD does not permit the simultaneous assessment of multiple walls and therefore is not compatible with clinical stress echocardiography while it could be used in a laboratory setting. Color TD provides a spatial map of velocity throughout the myocardium but its results are strongly affected by the frame rate. Both color TD and PWTD are also influenced by overall cardiac motion and tethering from adjacent segments and require reference velocity values for interpretation of regional left ventricular function. High frame rate (i.e. > 150 ms) post-processing-derived SRI can potentially overcome these limitations, since measurements of myocardial deformation have not any significant apex-to-base gradient. Preliminary studies have shown encouraging results about the ability of SRI to detect ischemia and viability, in terms of both strain rate changes and/or evidence of post-systolic thickening. SRI is, however, Doppler-dependent and time-consuming. Further technical refinements are needed to improve its application and introduce new ultrasound modalities to overcome the limitations of the Doppler-derived deformation analysis.

  18. Associations of physical activity, fitness, and body composition with heart rate variability-based indicators of stress and recovery on workdays: a cross-sectional study.

    Science.gov (United States)

    Teisala, Tiina; Mutikainen, Sara; Tolvanen, Asko; Rottensteiner, Mirva; Leskinen, Tuija; Kaprio, Jaakko; Kolehmainen, Marjukka; Rusko, Heikki; Kujala, Urho M

    2014-01-01

    The purpose of this study was to investigate how physical activity (PA), cardiorespiratory fitness (CRF), and body composition are associated with heart rate variability (HRV)-based indicators of stress and recovery on workdays. Additionally, we evaluated the association of objectively measured stress with self-reported burnout symptoms. Participants of this cross-sectional study were 81 healthy males (age range 26-40 y). Stress and recovery on workdays were measured objectively based on HRV recordings. CRF and anthropometry were assessed in laboratory conditions. The level of PA was based on a detailed PA interview (MET index [MET-h/d]) and self-reported activity class. PA, CRF, and body composition were significantly associated with levels of stress and recovery on workdays. MET index (P stress during working hours whereas body fat percentage (P = 0.005) was positively associated. Overall, 27.5% of the variance of total stress on workdays (P = 0.001) was accounted for by PA, CRF, and body composition. Body fat percentage and body mass index were negatively associated with night-time recovery whereas CRF was positively associated. Objective work stress was associated (P = 0.003) with subjective burnout symptoms. PA, CRF, and body composition are associated with HRV-based stress and recovery levels, which needs to be taken into account in the measurement, prevention, and treatment of work-related stress. The HRV-based method used to determine work-related stress and recovery was associated with self-reported burnout symptoms, but more research on the clinical importance of the methodology is needed.

  19. Construction and evaluation of a self rating scale for stress-induced exhaustion disorder, the Karolinska Exhaustion Disorder Scale.

    Science.gov (United States)

    Besèr, Aniella; Sorjonen, Kimmo; Wahlberg, Kristina; Peterson, Ulla; Nygren, Ake; Asberg, Marie

    2014-02-01

    Prolonged stress (≥ six months) may cause a condition which has been named exhaustion disorder (ED) with ICD-10 code F43.8. ED is characterised by exhaustion, cognitive problems, poor sleep and reduced tolerance to further stress. ED can cause long term disability and depressive symptoms may develop. The aim was to construct and evaluate a self-rating scale, the Karolinska Exhaustion Disorder Scale (KEDS), for the assessment of ED symptoms. A second aim was to examine the relationship between self-rated symptoms of ED, depression, and anxiety using KEDS and the Hospital Anxiety and Depression Scale (HAD). Items were selected based on their correspondence to criteria for ED as formulated by the Swedish National Board of Health and Welfare (NBHW), with seven response alternatives in a Likert-format. Self-ratings performed by 317 clinically assessed participants were used to analyse the scale's psychometric properties. KEDS consists of nine items with a scale range of 0-54. Receiver operating characteristics analysis demonstrated that a cut-off score of 19 was accompanied by high sensitivity and specificity (each above 95%) in the discrimination between healthy subjects and patients with ED. Reliability was satisfactory and confirmatory factor analysis revealed that ED, depression and anxiety are best regarded as different phenomena. KEDS may be a useful tool in the assessment of symptoms of Exhaustion Disorder in clinical as well as research settings. There is evidence that the symptom clusters of ED, anxiety and depression, respectively, reflect three different underlying dimensions. © 2013 The Authors. Scandinavian Journal of Psychology published by Scandinavian Psychological Associations and John Wiley & Sons Ltd.

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

    Directory of Open Access Journals (Sweden)

    Fábio Luis Nogueira Natal

    2013-12-01

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

  1. The relationship of work stress and family stress to the self-rated health of women employed in the industrial sector in Korea.

    Science.gov (United States)

    Kim, Gwang Suk; Cho, Won Jung; Lee, Chung Yul; Marion, Lucy N; Kim, Mi Ja

    2005-01-01

    To identify the relationship of work stress and family stress to the health of women in Korea. Cross-sectional study. Three hundred and thirty-one married women working in 14 manufacturing companies in Korea. Subjects responded to a questionnaire that included items on work stress, family stress, social support, and general characteristics. Perceived health status (PHS) was assessed with the Short Form-36. There was a significant positive relationship between social support and PHS, but significant negative relationships were found between PHS and work stress as well as family stress. Hierarchical multiple regression analysis explained the health status of married working women by four categories: personal, work related, family related, and social support, and accounted for 45.4% of the variance. When family-related factors were added to the model, the power of explanation was increased by 17.9% compared with the explained variance. Family stress was a major variable not only for explaining the variance but also for correlating with health status. Both work stress and family stress should be considered together when addressing the health of working women in the industrial sector in Korea.

  2. Stress-associated cardiovascular reaction masks heart rate dependence on physical load in mice.

    Science.gov (United States)

    Andreev-Andrievskiy, A A; Popova, A S; Borovik, A S; Dolgov, O N; Tsvirkun, D V; Custaud, M; Vinogradova, O L

    2014-06-10

    When tested on the treadmill mice do not display a graded increase of heart rate (HR), but rather a sharp shift of cardiovascular indices to high levels at the onset of locomotion. We hypothesized that under test conditions cardiovascular reaction to physical load in mice is masked with stress-associated HR increase. To test this hypothesis we monitored mean arterial pressure (MAP) and heart rate in C57BL/6 mice after exposure to stressful stimuli, during spontaneous locomotion in the open-field test, treadmill running or running in a wheel installed in the home cage. Mice were treated with β1-adrenoblocker atenolol (2mg/kg ip, A), cholinolytic ipratropium bromide (2mg/kg ip, I), combination of blockers (A+I), anxiolytic diazepam (5mg/kg ip, D) or saline (control trials, SAL). MAP and HR in mice increased sharply after handling, despite 3weeks of habituation to the procedure. Under stressful conditions of open field test cardiovascular parameters in mice were elevated and did not depend on movement speed. HR values did not differ in I and SAL groups and were reduced with A or A+I. HR was lower at rest in D pretreated mice. In the treadmill test HR increase over speeds of 6, 12 and 18m/min was roughly 1/7-1/10 of HR increase observed after placing the mice on the treadmill. HR could not be increased with cholinolytic (I), but was reduced after sympatholytic (A) or A+I treatment. Anxiolytic (D) reduced heart rate at lower speeds of movement and its overall effect was to unmask the dependency of HR on running speed. During voluntary running in non-stressful conditions of the home cage HR in mice linearly increased with increasing running speeds. We conclude that in test situations cardiovascular reactions in mice are governed predominantly by stress-associated sympathetic activation, rendering efforts to evaluate HR and MAP reactions to workload unreliable. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Oxidative stress does not influence local sweat rate during high-intensity exercise.

    Science.gov (United States)

    Meade, Robert D; Fujii, Naoto; Poirier, Martin P; Boulay, Pierre; Sigal, Ronald J; Kenny, Glen P

    2018-02-01

    What is the central question of this study? We evaluated whether oxidative stress attenuates the contribution of nitric oxide to sweating during high-intensity exercise. What is the main finding and its importance? In contrast to our previous report of an oxidative stress-mediated reduction in nitric oxide-dependent cutaneous vasodilatation in this cohort during intense exercise, we demonstrated no influence of local ascorbate administration on the sweating response during moderate- (∼51% peak oxygen uptake) or high-intensity exercise (∼72% peak oxygen uptake). These new findings provide important mechanistic insight into how exercise-induced oxidative stress impacts sudomotor activity. Nitric oxide (NO)-dependent sweating is diminished during high- but not moderate-intensity exercise. We evaluated whether this impairment stems from increased oxidative stress during high-intensity exercise. On two separate days, 11 young (24 ± 4 years) men cycled in the heat (35°C) at a moderate [500 W; 52 ± 6% peak oxygen uptake (V̇O2 peak )] or high (700 W; 71 ± 5% V̇O2 peak ) rate of metabolic heat production. Each session included two 30 min exercise bouts separated by a 20 min recovery period. Local sweat rate was monitored at four forearm skin sites continuously perfused via intradermal microdialysis with the following: (i) lactated Ringer solution (Control); (ii) 10 mm ascorbate (Ascorbate; non-selective antioxidant); (iii) 10 mm N G -nitro-l-arginine methyl ester (l-NAME; NO synthase inhibitor); or (iv) 10 mm ascorbate plus 10 mm l-NAME (Ascorbate + l-NAME). During moderate exercise, sweat rate was attenuated at the l-NAME and Ascorbate + l-NAME sites (both ∼1.0 mg min -1  cm -2 ; all P < 0.05) but not at the Ascorbate site (∼1.1 mg min -1  cm -2 ; both P ≥ 0.28) in comparison to the Control site (∼1.1 mg min -1  cm -2 ). However, no differences were observed between treatment sites (∼1.4 mg min -1  cm -2 ; P = 0

  4. Click trains and the rate of information processing: does "speeding up" subjective time make other psychological processes run faster?

    Science.gov (United States)

    Jones, Luke A; Allely, Clare S; Wearden, John H

    2011-02-01

    A series of experiments demonstrated that a 5-s train of clicks that have been shown in previous studies to increase the subjective duration of tones they precede (in a manner consistent with "speeding up" timing processes) could also have an effect on information-processing rate. Experiments used studies of simple and choice reaction time (Experiment 1), or mental arithmetic (Experiment 2). In general, preceding trials by clicks made response times significantly shorter than those for trials without clicks, but white noise had no effects on response times. Experiments 3 and 4 investigated the effects of clicks on performance on memory tasks, using variants of two classic experiments of cognitive psychology: Sperling's (1960) iconic memory task and Loftus, Johnson, and Shimamura's (1985) iconic masking task. In both experiments participants were able to recall or recognize significantly more information from stimuli preceded by clicks than those preceded by silence.

  5. Estimation of Subjective Mental Work Load Level with Heart Rate Variability by Tolerance to Driver's Mental Load

    Science.gov (United States)

    Yokoi, Toshiyuki; Itoh, Michimasa; Oguri, Koji

    Most of the traffic accidents have been caused by inappropriate driver's mental state. Therefore, driver monitoring is one of the most important challenges to prevent traffic accidents. Some studies for evaluating the driver's mental state while driving have been reported; however driver's mental state should be estimated in real-time in the future. This paper proposes a way to estimate quantitatively driver's mental workload using heart rate variability. It is assumed that the tolerance to driver's mental workload is different depending on the individual. Therefore, we classify people based on their individual tolerance to mental workload. Our estimation method is multiple linear regression analysis, and we compare it to NASA-TLX which is used as the evaluation method of subjective mental workload. As a result, the coefficient of correlation improved from 0.83 to 0.91, and the standard deviation of error also improved. Therefore, our proposed method demonstrated the possibility to estimate mental workload.

  6. Development of transformation bands in TiNi SMA for various stress and strain rates studied by a fast and sensitive infrared camera

    International Nuclear Information System (INIS)

    Pieczyska, E A; Kulasinski, K; Tobushi, H

    2013-01-01

    TiNi shape memory alloy (SMA) was subjected to tension at various strain rates for stress- and strain-controlled tests. The nucleation, development and saturation of the stress-induced martensitic transformation were investigated, based on the specimen temperature changes, measured by a fast and sensitive infrared camera. It was found that the initial, macroscopically homogeneous phase transformation occurs at the same stress level for all strain rates applied, regardless of the loading manner, while the stress of the localized transformation increases with the strain rate. At higher strain rate, a more dynamic course of the transformation process was observed, revealed in the creation of numerous fine transformation bands. An inflection point was noticed on the stress–strain curve, dividing the transformation range into two stages: the first heterogeneous, where transformation bands nucleate and evolve throughout the sample; the second, where the bands overlap, related to significant temperature increase and an upswing region of the curve. In the final part of the SMA loading a decrease of the average sample temperature revealed the saturation stage of the transformation. It was also observed that nucleation of the localized martensitic forward transformation takes place in the weakest area of the sample in both approaches, whereas the reverse transformation always initiates in its central part. (paper)

  7. Heart rate variability analysis in healthy subjects, patients suffering from congestive heart failure and heart transplanted patients

    Directory of Open Access Journals (Sweden)

    Argentina Leite

    2013-12-01

    Full Text Available This study aimed to find parameters to characterize heart rate variability (HRV and discriminate healthy subjects and patients with heart diseases. The parameters used for discrimination characterize the different components of HRV memory (short and long and are extracted from HRV recordings using parametric as well as non parametric methods. Thus, the parameters are: spectral components at low frequencies (LH and high frequencies (HF which are associated with the short memory of HRV and the long memory parameter (d obtained from autoregressive fractionally integrated moving average (ARFIMA models. In the non parametric context, short memory (α1 and long memory (α2 parameters are obtained from detrended fluctuation analysis (DFA. The sample used in this study contains 24-hour Holter HRV recordings of 30 subjects: 10 healthy individuals, 10 patients suffering from congestive heart failure and 10 heart transplanted patients from the Noltisalis database. It was found that short memory parameters present higher values for the healthy individuals whereas long memory parameters present higher values for the diseased individuals. Moreover, there is evidence that ARFIMA modeling allows the discrimination between the 3 groups under study, being advantageous over DFA.

  8. Girls, Boys and Subject Choice: A Report on Sex Differences in Participation Rates in Subjects in Western Australian Government Secondary Schools. Discussion Paper No. 11.

    Science.gov (United States)

    Brown, Sandra; Fitzpatrick, Jim

    Many of the issues confronting schools and society relate to the changing roles of males and females. Concern has also been expressed over the preparedness of graduates to face an uncertain job market and rapid technological change. To study the relationship between school subject choice and career opportunities for Australian youth, school…

  9. Structured health care for subjects with diabetic foot ulcers results in a reduction of major amputation rates

    Science.gov (United States)

    2013-01-01

    Objective We tested the effects of structured health care for the diabetic foot in one region in Germany aiming to reduce the number of major amputations. Research design and methods In a prospective study we investigated patients with diabetic foot in a structured system of outpatient, in-patient and rehabilitative treatment. Subjects were recruited between January 1st, 2000 and December 31, 2007. All participants underwent a two-year follow-up. The modified University of Texas Wound Classification System (UT) was the basis for documentation and data analysis. We evaluated numbers of major amputations, rates of ulcer healing and mortality. In order to compare the effect of the structured health care program with usual care in patients with diabetic foot we evaluated the same parameters at another regional hospital without interdisciplinary care of diabetic foot (controls). Results 684 patients with diabetic foot and 508 controls were investigated. At discharge from hospital 28.3% (structured health care program, SHC) vs. 23.0% (controls) of all ulcers had healed completely. 51.5% (SHC) vs. 49.8% (controls) were in UT grade 1. Major amputations were performed in 32 subjects of the structured health care program group (4.7%) vs. 110 (21.7%) in controls (p<0.0001). Mortality during hospitalization was 2.5% (SHC) vs. 9.4% in controls (p<0.001). Conclusions With the structured health care program we achieved a significant reduction of major amputation rates by more than 75% as compared to standard care. PMID:23497152

  10. Associations of acute stress and overnight heart rate with feed efficiency in beef heifers.

    Science.gov (United States)

    Munro, J C; Schenkel, F S; Physick-Sheard, P W; Fontoura, A B P; Miller, S P; Tennessen, T; Montanholi, Y R

    2017-03-01

    Proxies have the potential to accelerate feed efficiency (residual feed intake (RFI); kg dry matter/day) improvement, assisting with the reduction of beef cattle feed costs and environmental impact. Heart rate (HR) (beats per minute (BPM)) is associated with feed efficiency and influenced by autonomic activity and peripheral metabolism, suggesting HR could be used as a proxy for feed efficiency. Objectives were to assess associations between overnight HR, lying patterns and RFI, and between acute stress HR and RFI. Heifer calves (n=107; 408±28 days of age, 341±42.2 kg) and yearling heifers (n=36; 604±92 days of age, 539±52.2 kg) were exposed to a performance test to determine productive performance. Overnight HR (electrode based) and lying patterns (accelerometer based) were monitored on a subgroup of heifer calves (n=40; 20 lowest RFI; 20 highest RFI). In the 10-min acute stress assessment, all heifers were individually exposed to the opening and closing of an umbrella and HR before (HRBEF), in response to (HRMAX), after (HRAFT) and change (HRCHG; HRAFT-HRBEF) as a result of exposure were determined. Using polynomial regression, rate of HR decrease pre-exposure (β 1) and rates of HR increase (β 2) and decrease (β 3, β 4) post-exposure were determined. Heifer calves in the overnight assessment were classified into equal RFI groups (low RFI; high RFI) and HR means were treated as repeated measures and compared using multiple regression. In the acute stress assessment, heifers were classified within cattle category into equal RFI groups (low RFI; high RFI) and means and polynomial regression parameters were compared using multiple regression. Low-RFI heifer calves had a lower overnight HR (69.2 v. 72.6 BPM), similar HR change from lying to standing intervals (8.9 v. 9.2 BPM) and similar time lying (61.1% v. 64.5%) compared with high-RFI heifer calves. Low-RFI heifer calves had a higher absolute HRMAX (162.9 v. 145.7 BPM) and β 2 (-0.34 v. -0.20) than high

  11. HEART RATE, MOOD STATES, AND RATING OF PERCEIVED EXERTION AMONG ELDERLY SUBJECTS DURING 3.5 HOURS OF RECREATIONAL ALPINE SKIING

    Directory of Open Access Journals (Sweden)

    Sabine Krautgasser

    2012-12-01

    immediate positive psychological effects on the elderly subjects. Furthermore, recreational alpine skiing has a positive effect on MS ratings reflecting wellbeing, while generating age-appropriate moderate RPE values in elderly alpine skiers.

  12. Linear and nonlinear analysis of heart rate variability in healthy subjects and after acute myocardial infarction in patients

    Directory of Open Access Journals (Sweden)

    V.C. Kunz

    2012-05-01

    Full Text Available The objectives of this study were to evaluate and compare the use of linear and nonlinear methods for analysis of heart rate variability (HRV in healthy subjects and in patients after acute myocardial infarction (AMI. Heart rate (HR was recorded for 15 min in the supine position in 10 patients with AMI taking β-blockers (aged 57 ± 9 years and in 11 healthy subjects (aged 53 ± 4 years. HRV was analyzed in the time domain (RMSSD and RMSM, the frequency domain using low- and high-frequency bands in normalized units (nu; LFnu and HFnu and the LF/HF ratio and approximate entropy (ApEn were determined. There was a correlation (P < 0.05 of RMSSD, RMSM, LFnu, HFnu, and the LF/HF ratio index with the ApEn of the AMI group on the 2nd (r = 0.87, 0.65, 0.72, 0.72, and 0.64 and 7th day (r = 0.88, 0.70, 0.69, 0.69, and 0.87 and of the healthy group (r = 0.63, 0.71, 0.63, 0.63, and 0.74, respectively. The median HRV indexes of the AMI group on the 2nd and 7th day differed from the healthy group (P < 0.05: RMSSD = 10.37, 19.95, 24.81; RMSM = 23.47, 31.96, 43.79; LFnu = 0.79, 0.79, 0.62; HFnu = 0.20, 0.20, 0.37; LF/HF ratio = 3.87, 3.94, 1.65; ApEn = 1.01, 1.24, 1.31, respectively. There was agreement between the methods, suggesting that these have the same power to evaluate autonomic modulation of HR in both AMI patients and healthy subjects. AMI contributed to a reduction in cardiac signal irregularity, higher sympathetic modulation and lower vagal modulation.

  13. Rates of trauma spectrum disorders and risks of posttraumatic stress disorder in a sample of orphaned and widowed genocide survivors

    Directory of Open Access Journals (Sweden)

    Susanne Schaal

    2011-06-01

    Full Text Available During the Rwandan genocide of 1994, nearly one million people were killed within a period of 3 months.The objectives of this study were to investigate the levels of trauma exposure and the rates of mental health disorders and to describe risk factors of posttraumatic stress reactions in Rwandan widows and orphans who had been exposed to the genocide.Trained local psychologists interviewed orphans (n=206 and widows (n=194. We used the PSS-I to assess posttraumatic stress disorder (PTSD, the Hopkins Symptom Checklist to assess depression and anxiety symptoms, and the M.I.N.I. to assess risk of suicidality.Subjects reported having been exposed to a high number of different types of traumatic events with a mean of 11 for both groups. Widows displayed more severe mental health problems than orphans: 41% of the widows (compared to 29% of the orphans met symptom criteria for PTSD and a substantial proportion of widows suffered from clinically significant depression (48% versus 34% and anxiety symptoms (59% versus 42% even 13 years after the genocide. Over one-third of respondents of both groups were classified as suicidal (38% versus 39%. Regression analysis indicated that PTSD severity was predicted mainly by cumulative exposure to traumatic stressors and by poor physical health status. In contrast, the importance given to religious/spiritual beliefs and economic variables did not correlate with symptoms of PTSD.While a significant portion of widows and orphans continues to display severe posttraumatic stress reactions, widows seem to constitute a particularly vulnerable survivor group. Our results point to the chronicity of mental health problems in this population and show that PTSD may endure over time if not addressed by clinical intervention. Possible implications of poor mental health and the need for psychological intervention are discussed.

  14. Metabolite Profiling of Barley Grains Subjected to Water Stress: To Explain the Genotypic Difference in Drought-Induced Impacts on Malting Quality

    Directory of Open Access Journals (Sweden)

    Xiaojian Wu

    2017-09-01

    Full Text Available Grain weight and protein content will be reduced and increased, respectively, when barley is subjected to water stress after anthesis, consequently deteriorating the malt quality. However, such adverse impact of water stress differs greatly among barley genotypes. In this study, two Tibetan wild barley accessions and two cultivated varieties differing in water stress tolerance were used to investigate the genotypic difference in metabolic profiles during grain-filling stage under drought condition. Totally, 71 differently accumulated metabolites were identified, including organic acids, amino acids/amines, and sugars/sugar alcohols. Their relative contents were significantly affected by water stress for all genotypes and differed distinctly between the wild and cultivated barleys. The principal component analysis of metabolites indicated that the Tibetan wild barley XZ147 possessed a unique response to water stress. When subjected to water stress, the wild barley XZ147 showed the most increase of β-amylase activity among the four genotypes, as a result of its higher lysine content, less indole-3-acetic acid (IAA biosynthesis, more stable H2O2 homeostasis, and more up-regulation of BMY1 gene. On the other hand, XZ147 had the most reduction of β-glucan content under water stress than the other genotypes, which could be explained by the faster grain filling process and the less expression of β-glucan synthase gene GSL7. All these results indicated a great potential for XZ147 in barley breeding for improving water stress tolerance.

  15. Complexity and time asymmetry of heart rate variability are altered in acute mental stress.

    Science.gov (United States)

    Visnovcova, Z; Mestanik, M; Javorka, M; Mokra, D; Gala, M; Jurko, A; Calkovska, A; Tonhajzerova, I

    2014-07-01

    We aimed to study the complexity and time asymmetry of short-term heart rate variability (HRV) as an index of complex neurocardiac control in response to stress using symbolic dynamics and time irreversibility methods. ECG was recorded at rest and during and after two stressors (Stroop, arithmetic test) in 70 healthy students. Symbolic dynamics parameters (NUPI, NCI, 0V%, 1V%, 2LV%, 2UV%), and time irreversibility indices (P%, G%, E) were evaluated. Additionally, HRV magnitude was quantified by linear parameters: spectral powers in low (LF) and high frequency (HF) bands. Our results showed a reduction of HRV complexity in stress (lower NUPI with both stressors, lower NCI with Stroop). Pattern classification analysis revealed significantly higher 0V% and lower 2LV% with both stressors, indicating a shift in sympathovagal balance, and significantly higher 1V% and lower 2UV% with Stroop. An unexpected result was found in time irreversibility: significantly lower G% and E with both stressors, P% index significantly declined only with arithmetic test. Linear HRV analysis confirmed vagal withdrawal (lower HF) with both stressors; LF significantly increased with Stroop and decreased with arithmetic test. Correlation analysis revealed no significant associations between symbolic dynamics and time irreversibility. Concluding, symbolic dynamics and time irreversibility could provide independent information related to alterations of neurocardiac control integrity in stress-related disease.

  16. Heart rate variability associated with posttraumatic stress disorder in victims' families of sewol ferry disaster.

    Science.gov (United States)

    Lee, Sang Min; Han, Hyesung; Jang, Kuk-In; Huh, Seung; Huh, Hyu Jung; Joo, Ji-Young; Chae, Jeong-Ho

    2018-01-01

    Posttraumatic stress disorder (PTSD), which is caused by a major traumatic event, has been associated with autonomic nervous function. However, there have been few explorations of measuring biological stress in the victims' family members who have been indirectly exposed to the disaster. Therefore, this longitudinal study examined the heart rate variability (HRV) of the family members of victims of the Sewol ferry disaster. We recruited 112 family members of victims 18 months after the disaster. Sixty-seven participants were revisited at the 30 months postdisaster time point. HRV and psychiatric symptoms including PTSD, depression and anxiety were evaluated at each time point. Participants with PTSD had a higher low frequency to high frequency ratio (LF:HF ratio) than those without PTSD. Logistic regression analysis showed that the LF:HF ratio at 18 months postdisaster was associated with a PTSD diagnosis at 30 months postdisaster. These results suggest that disrupted autonomic nervous system functioning for longer than a year after trauma exposure contributes to predicting PTSD vulnerability. Our finding may contribute to understand neurophysiologic mechanisms underlying secondary traumatic stress. Future studies will be needed to clarify the interaction between autonomic regulation and trauma exposure. Copyright © 2017. Published by Elsevier B.V.

  17. Self-Steem and changes in heart rate during laboratory-based stress

    Directory of Open Access Journals (Sweden)

    Brian M. Hughes

    2003-01-01

    Full Text Available The relationship between self-esteem (SE, type of stressor, and fluctuations in heart rate was assessed in a sample of 59 college students (40 females, 19 males; with a mean age of 23.98 years (SEM = 1.0. SE was measured using the Rosenberg Self-Esteem Scale. The study assessed whether SE buffers the cardiovascular response to stress by comparing responses to two types of stressor: mental arithmetic and verbal memory. As predicted, an SE x stressor interaction was found (p = 0.039. High-SE participants found both stressors moderately stressful but low-SE participants found the mental arithmetic task particularly stressful. This is consistent with the view that mental arithmetic elicits a specific fear that exceeds that associated with other domains of performance. The present study suggests that such fear affects low-SE participants more strongly than high-SE participants. The interaction was statistically independent of potential physiological contaminants such as gender, age, smoking, and caffeine consumption.

  18. Complexity and time asymmetry of heart rate variability are altered in acute mental stress

    International Nuclear Information System (INIS)

    Visnovcova, Z; Mestanik, M; Javorka, M; Mokra, D; Calkovska, A; Tonhajzerova, I; Gala, M; Jurko, A

    2014-01-01

    We aimed to study the complexity and time asymmetry of short-term heart rate variability (HRV) as an index of complex neurocardiac control in response to stress using symbolic dynamics and time irreversibility methods. ECG was recorded at rest and during and after two stressors (Stroop, arithmetic test) in 70 healthy students. Symbolic dynamics parameters (NUPI, NCI, 0V%, 1V%, 2LV%, 2UV%), and time irreversibility indices (P%, G%, E) were evaluated. Additionally, HRV magnitude was quantified by linear parameters: spectral powers in low (LF) and high frequency (HF) bands. Our results showed a reduction of HRV complexity in stress (lower NUPI with both stressors, lower NCI with Stroop). Pattern classification analysis revealed significantly higher 0V% and lower 2LV% with both stressors, indicating a shift in sympathovagal balance, and significantly higher 1V% and lower 2UV% with Stroop. An unexpected result was found in time irreversibility: significantly lower G% and E with both stressors, P% index significantly declined only with arithmetic test. Linear HRV analysis confirmed vagal withdrawal (lower HF) with both stressors; LF significantly increased with Stroop and decreased with arithmetic test. Correlation analysis revealed no significant associations between symbolic dynamics and time irreversibility. Concluding, symbolic dynamics and time irreversibility could provide independent information related to alterations of neurocardiac control integrity in stress-related disease. (paper)

  19. Short communication: Effect of heat stress on nonreturn rate of Italian Holstein cows.

    Science.gov (United States)

    Biffani, S; Bernabucci, U; Vitali, A; Lacetera, N; Nardone, A

    2016-07-01

    The data set consisted of 1,016,856 inseminations of 191,012 first, second, and third parity Holstein cows from 484 farms. Data were collected from year 2001 through 2007 and included meteorological data from 35 weather stations. Nonreturn rate at 56 d after first insemination (NR56) was considered. A logit model was used to estimate the effect of temperature-humidity index (THI) on reproduction across parities. Then, least squares means were used to detect the THI breakpoints using a 2-phase linear regression procedure. Finally, a multiple-trait threshold model was used to estimate variance components for NR56 in first and second parity cows. A dummy regression variable (t) was used to estimate NR56 decline due to heat stress. The NR56, both for first and second parity cows, was significantly (unfavorable) affected by THI from 4 d before 5 d after the insemination date. Additive genetic variances for NR56 increased from first to second parity both for general and heat stress effect. Genetic correlations between general and heat stress effects were -0.31 for first parity and -0.45 for second parity cows. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  20. Predicting changes in posttraumatic growth and subjective well-being among breast cancer survivors: the role of social support and stress.

    Science.gov (United States)

    McDonough, Meghan H; Sabiston, Catherine M; Wrosch, Carsten

    2014-01-01

    Social support is theoretically expected to be positively associated with posttraumatic growth (PTG) and subjective well-being, and stress is expected to be positively associated with PTG and negatively associated with subjective well-being among breast cancer (BC) survivors. However, empirical evidence is mixed, predominantly cross-sectional, and few studies have examined the unique effects of these predictors on positive changes in psychological experiences post cancer diagnosis and systemic treatment. This study examined both general and BC-specific social support and stress as predictors of change in PTG and subjective well-being among BC survivors. Women (N = 173, Mage  = 55.40, SD = 10.99) who had recently finished treatment completed demographic and treatment measures at baseline (T1); general and cancer-specific social support and stress, PTG and subjective well-being at 3 months (T2); and PTG and subjective well-being again at 6 months (T3). Longitudinal predictors of change in PTG and subjective well-being were examined using hierarchical multiple regression. The BC-specific social support (β = .12) and stress (cancer worry; β = .10) predicted increasing levels of PTG. Improvements in subjective well-being were predicted by higher levels of general social support (β = .21) and lower levels of general stress (β = -.59). There are distinct predictors of change in PTG and subjective well-being among BC survivors, supporting the distinction between the trauma-specific process of PTG and well-being. Copyright © 2013 John Wiley & Sons, Ltd.

  1. Effect of facial self-resemblance on the startle response and subjective ratings of erotic stimuli in heterosexual men.

    Science.gov (United States)

    Lass-Hennemann, Johanna; Deuter, Christian E; Kuehl, Linn K; Schulz, Andre; Blumenthal, Terry D; Schachinger, Hartmut

    2011-10-01

    Cues of kinship are predicted to increase prosocial behavior due to the benefits of inclusive fitness, but to decrease approach motivation due to the potential costs of inbreeding. Previous studies have shown that facial resemblance, a putative cue of kinship, increases prosocial behavior. However, the effects of facial resemblance on mating preferences are equivocal, with some studies finding that facial resemblance decreases sexual attractiveness ratings, while other studies show that individuals choose mates partly on the basis of similarity. To further investigate this issue, a psychophysiological measure of affective processing, the startle response, was used in this study, assuming that differences in approach motivation to erotic pictures will modulate startle. Male volunteers (n = 30) viewed 30 pictures of erotic female nudes while startle eyeblink responses were elicited by acoustic noise probes. The female nude pictures were digitally altered so that the face either resembled the male participant or another participant, or were not altered. Non-nude neutral pictures were also included. Importantly, the digital alteration was undetected by the participants. Erotic pictures were rated as being pleasant and clearly reduced startle eyeblink magnitude as compared to neutral pictures. Participants showed greater startle inhibition to self-resembling than to other-resembling or non-manipulated female nude pictures, but subjective pleasure and arousal ratings did not differ among the three erotic picture categories. Our data suggest that visual facial resemblance of opposite-sex nudes increases approach motivation in men, and that this effect was not due to their conscious evaluation of the erotic stimuli.

  2. ω-3 and folic acid act against depressive-like behavior and oxidative damage in the brain of rats subjected to early- or late-life stress.

    Science.gov (United States)

    Réus, Gislaine Z; Maciel, Amanda L; Abelaira, Helena M; de Moura, Airam B; de Souza, Thays G; Dos Santos, Thais R; Darabas, Ana Caroline; Parzianello, Murilo; Matos, Danyela; Abatti, Mariane; Vieira, Ana Carolina; Fucillini, Vanessa; Michels, Monique; Dal-Pizzol, Felipe; Quevedo, João

    2018-03-30

    To investigate the antidepressant and antioxidant effects of omega-3, folic acid and n-acetylcysteine (NAC) in rats which were subjected to early or late life stress. Early stress was induced through maternal deprivation (MD), while late life stress was induced using the chronic mild stress (CMS) protocol. Young rats which were subjected to MD and the adult rats which were subjected to CMS were treated with omega-3 fatty acids (0.72 g/kg), NAC (20 mg/kg) or folic acid (50 mg/kg) once/day, for a period of 20 days. Then, the animals' immobility times were evaluated using the forced swimming test. Oxidative stress parameters were evaluated in the brain. Depressive-like behavior induced by CMS was prevented by NAC and folic acid, and depressive-like behavior induced by MD was prevented by NAC, folic acid and omega-3. NAC, folic acid and omega-3 were able to exert antioxidant effects in the brain of rats subjected to CMS or MD. These preventive treatments decreased the levels of protein carbonylation and lipid peroxidation, and also decreased the concentrations of nitrite/nitrate and reduced the activity of myeloperoxidase activity in the rat brain which was induced by CMS or MD. NAC, folic acid and omega-3 increased superoxide dismutase and catalase activities in the rat brain subjected to early or late life stress. NAC, omega-3 and folic acid may present interesting lines of treatment based on their antioxidant properties, which cause an inhibition of behavioral and brain changes that occur from stressful life events. Copyright © 2018 Elsevier Inc. All rights reserved.

  3. Imbalance of heterologous protein folding and disulfide bond formation rates yields runaway oxidative stress

    Directory of Open Access Journals (Sweden)

    Tyo Keith EJ

    2012-03-01

    Full Text Available Abstract Background The protein secretory pathway must process a wide assortment of native proteins for eukaryotic cells to function. As well, recombinant protein secretion is used extensively to produce many biologics and industrial enzymes. Therefore, secretory pathway dysfunction can be highly detrimental to the cell and can drastically inhibit product titers in biochemical production. Because the secretory pathway is a highly-integrated, multi-organelle system, dysfunction can happen at many levels and dissecting the root cause can be challenging. In this study, we apply a systems biology approach to analyze secretory pathway dysfunctions resulting from heterologous production of a small protein (insulin precursor or a larger protein (α-amylase. Results HAC1-dependent and independent dysfunctions and cellular responses were apparent across multiple datasets. In particular, processes involving (a degradation of protein/recycling amino acids, (b overall transcription/translation repression, and (c oxidative stress were broadly associated with secretory stress. Conclusions Apparent runaway oxidative stress due to radical production observed here and elsewhere can be explained by a futile cycle of disulfide formation and breaking that consumes reduced glutathione and produces reactive oxygen species. The futile cycle is dominating when protein folding rates are low relative to disulfide bond formation rates. While not strictly conclusive with the present data, this insight does provide a molecular interpretation to an, until now, largely empirical understanding of optimizing heterologous protein secretion. This molecular insight has direct implications on engineering a broad range of recombinant proteins for secretion and provides potential hypotheses for the root causes of several secretory-associated diseases.

  4. Increased rate of acceleration on Pine Island Glacier strongly coupled to changes in gravitational driving stress

    Directory of Open Access Journals (Sweden)

    J. B. T. Scott

    2009-05-01

    Full Text Available Pine Island Glacier, Antarctica, has been undergoing several related changes for at least two decades; these include acceleration, thinning and grounding line retreat. During the first major ground-based study between 2006 and 2008, GPS receivers were used to monitor ice flow from 55 km to 171 km inland, along the central flowline. At four sites both acceleration and thinning rates over the last two years exceeded rates observed at any other time over the last two decades. At the downstream site acceleration was 6.4% over 2007 and thinning was 3.5±0.5 ma−1. Acceleration and thinning have spread rapidly inland with the acceleration 171 km inland at 4.1% over 2007, greater than any measured annual flow increase along the whole glacier prior to 2006. Increases in surface slope, and hence gravitational driving stress, correlate well with the acceleration and no sustained change in longitudinal stress gradient is needed to explain the force balance. There is no indication that the glacier is approaching a new steady state.

  5. Relating high-temperature flow stress of AISI 316 stainless steel to strain and strain rate

    International Nuclear Information System (INIS)

    Matteazzi, S.; Paitti, G.; Boerman, D.

    1982-01-01

    The authors have performed an experimental determination of tensile stress-strain curves for different strain rates (4.67 x 10 - 5 , 4.67 x 10 - 2 s - 1 ) and for a variety of temperature conditions (773-1073 K) of AISI 316H stainless steel (annealed conditions) and also a computer analysis of the experimental curves using a fitting program which takes into consideration different constitutive relations describing the plastic flow behaviour of the metals. The results show that the materials tested are clearly affected by strain rate only at the highest temperature investigated (1073 K) and that the plastic strain is the more significant variable. Of the constitutive equations considered, Voce's relation gives the best fit for the true stress-time-strain curves. However, the Ludwik and Ludwigson equations also provide a description of the experimental data, whereas Hollomon's equation does not suitably characterize AISI 316H stainless steel and can be applied with some accuracy only at 1073 K. (author)

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

    Science.gov (United States)

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

    2018-08-01

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