WorldWideScience

Sample records for subjective stress ratings

  1. Physical activity, heart rate variability-based stress and recovery, and subjective stress during a 9-month study period.

    Science.gov (United States)

    Föhr, T; Tolvanen, A; Myllymäki, T; Järvelä-Reijonen, E; Peuhkuri, K; Rantala, S; Kolehmainen, M; Korpela, R; Lappalainen, R; Ermes, M; Puttonen, S; Rusko, H; Kujala, U M

    2017-06-01

    The aim of this study was to investigate the association between physical activity (PA) and objective heart rate variability (HRV)-based stress and recovery with subjective stress in a longitudinal setting. Working-age participants (n = 221; 185 women, 36 men) were overweight (body mass index, 25.3-40.1 kg/m(2) ) and psychologically distressed (≥3/12 points on the General Health Questionnaire). Objective stress and recovery were based on HRV recordings over 1-3 work days. Subjective stress was assessed with the Perceived Stress Scale and PA level with a questionnaire. Data were collected at three time points: baseline, 10 weeks post intervention, and at the 36-week follow-up. We adopted a latent growth model to investigate the initial level and change in PA, objective stress and recovery, and subjective stress at the three measurement time points. The results showed that initial levels of PA (P stress (P = 0.001) and recovery (P stress. The results persisted after adjustment for intervention group. The present results suggest that high PA and objectively assessed low stress and good recovery have positive effects on changes in subjective stress in the long-term. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Salivary cortisol, heart rate, electrodermal activity and subjective stress responses to the Mannheim Multicomponent Stress Test (MMST).

    Science.gov (United States)

    Reinhardt, Tatyana; Schmahl, Christian; Wüst, Stefan; Bohus, Martin

    2012-06-30

    The availability of effective laboratory paradigms for inducing psychological stress is an important requirement for experimental stress research. Reliable protocols are scarce, usually laborious and manpower-intensive. In order to develop an economical, easily applicable standardized stress protocol, we have recently tailored the Mannheim Multicomponent Stress Test (MMST). This test has been shown to induce relatively high stress responses without focusing on social-evaluative components. In this study we evaluated changes in electrodermal activity and salivary cortisol in response to the MMST. The MMST simultaneously combines cognitive (mental arithmetic), emotional (affective pictures), acoustic (white noise) and motivational stressors (loss of money). This study comprised two independent experiments. For experiment 1, 80 female subjects were recruited; 30 subjects (15 females) participated in experiment 2. Significant changes in electrodermal activity and salivary cortisol levels in response to MMST exposure were found. Subjective stress and heart rate responses were significantly increased in both experiments. These results indicate that the MMST is an economical stress paradigm which is also applicable in larger cohorts or multicenter studies for investigating stress reactions. As social-evaluative threat is not the main stress component of the MMST, this procedure represents a useful and complementary alternative to other established stress protocols. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Increase in perceived stress is correlated to lower heart rate variability in healthy young subjects

    Directory of Open Access Journals (Sweden)

    Ana Gabriela Câmara Batista da Silva

    2015-06-01

    Full Text Available Emotional stress is a risk factor for cardiovascular disease. Decreased heart rate variability (HRV is associated to increased mortality rates in certain heart diseases. Current study assessed the co-relation between perceived stress and HRV parameters. The correlation between psychological stress, measured by the perceived stress scale (PSS-14, and HRV parameters obtained during 5 min. at rest was evaluated. Data from 35 healthy young volunteers demonstrated a significant correlation between PSS-14 scores and Low Frequency-LF (ms2 by frequency domain HRV analysis. Other variables such as High Frequency and Standard Deviation of R-R intervals had also negative coefficients but did not have any significant correlation with PSS-14. No correlation between PSS-14 and sympathovagal balance parameters was found. Data interpretation demonstrated that increase in perceived stress was correlated to decrease in heart rate variability, which may point out an important mechanism in cardiovascular pathophysiology that should be further investigated.

  4. Heart Rate Variability Biofeedback Stress Relief Program for Depression*. A Replicated Single-Subject Design.

    Science.gov (United States)

    Hartogs, Bregje M A; Bartels-Velthuis, Agna A; Van der Ploeg, Karen; Bos, Elske H

    2017-07-19

    Depressive disorders often have a chronic course and the efficacy of evidence-based treatments may be overestimated. To examine the effectiveness of the Heart Rate Variability Stress Reduction Program (SRP) as a supplement to standard treatment in patients with depressive disorders. The SRP was individually administered in eight weekly sessions. Seven participants completed the full protocol and were enrolled in a single-subject ABA multiple baseline experimental design. To perform interrupted time-series analyses, daily measures were completed in a diary (depression, resilience, happiness, heart coherence and a personalized outcome measure). Five out of seven patients improved in depressed mood and/or a personalized outcome measure. The effect of treatment was reversed in four patients during the withdrawal phase. One patient reliably improved on depression, whereas two patients recovered on autonomy and one on social optimism. No consistent relationship was found between the heart rate variability-related level of coherence and self-reported mood levels. The SRP is beneficial in some domains and for some patients. A prolonged treatment or continued home practice may be required for enduring effects. The intervention had more clinical impact on resilience-related outcome measures than on symptoms. The small sample size does not permit generalization of the results. We recommend future investigation of the underlying mechanisms of the SRP.

  5. Subjective stress, objective heart rate variability-based stress, and recovery on workdays among overweight and psychologically distressed individuals: a cross-sectional study.

    Science.gov (United States)

    Föhr, Tiina; Tolvanen, Asko; Myllymäki, Tero; Järvelä-Reijonen, Elina; Rantala, Sanni; Korpela, Riitta; Peuhkuri, Katri; Kolehmainen, Marjukka; Puttonen, Sampsa; Lappalainen, Raimo; Rusko, Heikki; Kujala, Urho M

    2015-01-01

    The present study aimed to investigate how subjective self-reported stress is associated with objective heart rate variability (HRV)-based stress and recovery on workdays. Another aim was to investigate how physical activity (PA), body composition, and age are associated with subjective stress, objective stress, and recovery. Working-age participants (n = 221; 185 women, 36 men) in this cross-sectional study were overweight (body mass index, 25.3-40.1 kg/m(2)) and psychologically distressed (≥3/12 points on the General Health Questionnaire). Objective stress and recovery were based on HRV recordings over 1-3 workdays. Subjective stress was assessed by the Perceived Stress Scale. PA level was determined by questionnaire, and body fat percentage was assessed by bioelectrical impedance analysis. Subjective stress was directly associated with objective stress (P = 0.047) and inversely with objective recovery (P = 0.046). These associations persisted after adjustments for sex, age, PA, and body fat percentage. Higher PA was associated with lower subjective stress (P = 0.037). Older age was associated with higher objective stress (P subjective stress (P = 0.043). The present results suggest that subjective self-reported stress is associated with objective physiological stress, but they are also apparently affected by different factors. However, some of the found associations among these overweight and psychologically distressed participants with low inter-individual variation in PA are rather weak and the clinical value of the present findings should be studied further among participants with greater heterogeneity of stress, PA and body composition. However, these findings suggest that objective stress assessment provides an additional aspect to stress evaluation. Furthermore, the results provide valuable information for developing stress assessment methods.

  6. 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.

  7. The response of polymethyl methacrylate (PMMA) subjected to large strains, high strain rates, high pressures, a range in temperatures, and variations in the intermediate principal stress

    Science.gov (United States)

    Holmquist, T. J.; Bradley, J.; Dwivedi, A.; Casem, D.

    2016-05-01

    This article presents the response of polymethyl methacrylate (PMMA) subjected to large strains, high strain rates, high pressures, a range in temperatures, and variations in the intermediate principal stress. Laboratory data from the literature, and new test data provided here, are used in the evaluation. The new data include uniaxial stress compression tests (at various strain rates and temperatures) and uniaxial stress tension tests (at low strain rates and ambient temperatures). The compression tests include experiments at ˙ɛ = 13,000 s-1, significantly extending the range of known strain rate data. The observed behavior of PMMA includes the following: it is brittle in compression at high rates, and brittle in tension at all rates; strength is dependent on the pressure, strain, strain rate, temperature, and the intermediate principal stress; the shear modulus increases as the pressure increases; and it is highly compressible. Also presented are novel, high velocity impact tests (using high-speed imaging) that provide insight into the initiation and evolution of damage. Lastly, computational constitutive models for pressure, strength, and failure are presented that provide responses that are in good agreement with the laboratory data. The models are used to compute several ballistic impact events for which experimental data are available.

  8. Subjective stress, salivary cortisol and electrophysiological responses to psychological stress

    Directory of Open Access Journals (Sweden)

    Mingming eQi

    2016-02-01

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

  9. 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.

  10. 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

  11. 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

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

    Science.gov (United States)

    Zhou, Rong; Yu, Xiaqing; Ottosen, Carl-Otto; Rosenqvist, Eva; Zhao, Liping; Wang, Yinlei; Yu, Wengui; Zhao, Tongmin; Wu, Zhen

    2017-01-25

    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. Shoot fresh and dry weight, leaf area 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 significantly decreased under drought and combined stress as compared to control. The tomato 'Arvento' was more affected by heat stress than 'LA1994' and 'LA2093' due to significant decreases in shoot dry weight, chlorophyll a and carotenoid content, starch content and NPQ (non-photochemical quenching) only in 'Arvento' under heat treatment. By comparison, the two heat-tolerant tomatoes were more affected by drought stress compared to 'Arvento' as shown by small stomatal and pore area, decreased sucrose content, ΦPSII (quantum yield of photosystem II), ETR (electron transport rate) and qL (fraction of open PSII centers) in 'LA1994' and 'LA2093'. The three cultivars showed similar response when subjected to the combination of drought and heat stress as shown by most physiological parameters, even though only 'LA1994' and 'LA2093' showed decreased Fv/Fm (maximum potential quantum efficiency of photosystem II), ΦPSII, ETR and qL under combined stress. The cultivars differing in heat sensitivity did not show difference in the combined stress sensitivity, indicating that selection for tomatoes

  13. Gum chewing modulates heart rate variability under noise stress.

    Science.gov (United States)

    Ekuni, Daisuke; Tomofuji, Takaaki; Takeuchi, Noriko; Morita, Manabu

    2012-12-01

    Gum chewing may relieve stress, although this hypothesis has not been proven. Heart-rate variability (HRV) is commonly used to measure stress levels. However, it is not known if gum chewing modulates HRV under acute stress. The aim of this study was to investigate the effects of gum chewing on HRV under acute stress. A cross-over study involving 47 non-smoking healthy subjects, aged 22-27 years, was carried out. The subjects received a stress procedure with gum chewing (GS group) and without gum chewing (S group). Additionally, the other 20 subjects were allocated to the gum chewing without stress group (G group). The GS and S groups were exposed to noise for 5 min (75 dBA) as stress. Before and after stress exposure/gum chewing, participants completed the state portion of the State-Trait Anxiety Inventory (STAI-s) and a single Stress Visual Analogue Scale (VAS) measurement. HRV measurement was performed before and during stress/gum chewing for 5 min. After the stress procedure, VAS score significantly increased in the GS and S groups. During the stress procedure, the GS group showed a significantly lower level of high frequency (HF) and higher levels of low frequency (LF) and LF/HF than the S group. However, there were no significant differences in the scores of the state portion of the State-Trait Anxiety Inventory (STAI-s) and VAS between the two stress groups. These findings suggest that gum chewing modulates HRV, but may not relieve acute stress caused by noise.

  14. Cortisol and subjective stress responses to acute psychosocial stress in fibromyalgia patients and control participants.

    Science.gov (United States)

    Coppens, Eline; Kempke, Stefan; Van Wambeke, Peter; Claes, Stephan; Morlion, Bart; Luyten, Patrick; Van Oudenhove, Lukas

    2017-12-11

    Hypothalamic-pituitary-adrenal (HPA) axis dysfunction may play a role in fibromyalgia (FM) pathogenesis, but remains understudied in this disorder. Furthermore, early childhood adversities (ECA) are common in FM, but whether they moderate stress reactivity is unknown. Hence, we investigated cortisol and subjective responses to acute psychosocial stress in FM and controls, while adjusting for ECA. Twenty-seven female FM patients and 24 age-matched female controls were recruited in a tertiary care center and through advertisements, respectively. The Childhood Trauma Questionnaire was used to measure ECA history. Salivary cortisol levels and subjective stress ratings were measured at multiple time points before and after the Trier Social Stress Test (TSST) was administered. Significant main effects of group [F(1,43)=7.04, p=0.011, lower in FM] and ECA [F(1,43)=5.18, p=0.028, higher in participants with ECA] were found for cortisol responses. When excluding controls with ECA (n=5), a significant group-by-time interaction was found [F(6,39)=2.60, p=0.032], driven by a blunted response to the stressor in FM compared with controls (p=0.037). For subjective stress responses, a significant main effect of group [F(1,45)=10.69, p=0.002, higher in FM] and a trend towards a group-by-time interaction effect [F(6,45)=2.05, p=0.078, higher in FM 30 minutes before and 30 and 75 minutes after the TSST, and impaired recovery (difference immediately after - 30 minutes after the TSST) in FM] were found. Blunted cortisol responsivity to the TSST was observed in FM patients compared with controls without ECA. FM patients had higher subjective stress levels compared with controls, particularly at baseline and during recovery from the TSST. In FM patients, ECA history was not associated with cortisol or subjective stress levels, or with responsivity to the TSST. Future research should investigate the mechanisms underlying HPA axis dysregulation in FM.

  15. Endocrinological and subjective stress responses in children with depressive, anxiety, or externalizing disorders.

    Science.gov (United States)

    Stadelmann, Stephanie; Jaeger, Sonia; Matuschek, Tina; Bae, Yoon Ju; von Klitzing, Kai; Klein, Annette Maria; Döhnert, Mirko

    2017-09-20

    In this study, we used a stress test to investigate endocrinological and subjective stress responses of 8- to 14-year-old children with internalizing or externalizing disorders and healthy controls. The sample (N = 170) consisted of clinical and community children. Parents were given a diagnostic interview to diagnose their children's psychiatric condition. We measured saliva cortisol and subjectively experienced arousal in children before and after the Trier Social Stress Test for Children. Children also rated their performance immediately after the stress test, and 1 hr later they rated their positive and negative thoughts about this stressful event. Children with internalizing or externalizing disorders exhibited a blunted cortisol response compared to healthy controls. Depressed children rated their test performance lower and reported more negative thoughts after the test in comparison to healthy controls, anxious children reported more arousal before and after the task, and children with externalizing disorders reported more positive thoughts. In regression analyses, cortisol and subjective stress responses were both predictive of psychiatric disorders. The study extends previous work on the relation between psychiatric disorders and children's stress responses to an experimentally induced stress task by including a broad range of psychiatric disorders and by integrating endocrinological and subjective stress responses.

  16. 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.

  17. Estimation of Subjective Stress in Acute Myocardial Infarction

    Directory of Open Access Journals (Sweden)

    Chockalingam A

    2003-01-01

    Full Text Available BACKGROUND and AIMS: Mental stress is considered to be a precipitating factor in acute coronary events. We aimed to assess the association of subjective or 'perceived' mental stress with the occurrence of acute coronary events. SETTINGS AND DESIGN: Prospective case-control survey was carried out in a referral teaching hospital. subjects & METHODS: Consecutive patients with acute myocardial infarction and ST elevation on electrocardiogram who were admitted to the Coronary Care Unit of a referral teaching hospital were enrolled in the study as cases. Controls were unmatched and were enrolled from amongst patients with coronary artery disease who did not have recent acute coronary events. Subjective Stress Functional Classification (SS-FC for the preceding 2-4 weeks was assessed and assigned four grades from I to IV as follows: I - baseline, II - more than usual but not affecting daily routine, III - significantly high stress affecting daily routine and IV - worst stress in life. STATISTICAL ANALYSIS: Proportions of different characteristics were compared using chi-square test with Yates continuity correction. Student's unpaired t test was applied for mean age. 'p' value of < 0.05 was considered statistically significant. RESULTS: SS-FC could be reliably (99% and easily assessed. Eighty (53% of the total 150 patients with acute MI reported 'high' levels of stress (stress class III and IV. This is in contrast to only 30 (20% of 150 healthy controls reporting high stress for the same period (p value < 0.001. CONCLUSION: Patients with acute myocardial infarction report a higher subjective mental stress during 2 to 4 weeks preceding the acute coronary event.

  18. 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; poxidative stress 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.

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

    African Journals Online (AJOL)

    2015-08-20

    Aug 20, 2015 ... catalase) and antioxidants Vitamins (A, C, and E). The. Oxidative stress among subjects with metabolic syndrome in Sokoto, North‑Western Nigeria. AA Sabir, LS Bilbis1, Y Saidu1, A Jimoh2, SO Iwuala3, SA Isezuo, AU Kaoje4, SA Abubakar5. Departments of Medicine and 4Community Health, Usmanu ...

  20. Acute short-term mental stress does not influence salivary flow rate dynamics.

    Directory of Open Access Journals (Sweden)

    Ella A Naumova

    Full Text Available BACKGROUND: Results of studies that address the influence of stress on salivary flow rate and composition are controversial. The aim of this study was to reveal the influence of stress vulnerability and different phases of stress reactivity on the unstimulated and stimulated salivary flow rate. We examined that acute mental stress does not change the salivary flow rate. In addition, we also examined the salivary cortisol and protein level in relation to acute mental stress stimuli. METHODS: Saliva of male subjects was collected for five minutes before, immediately, 10, 30 and 120 min after toothbrushing. Before toothbrushing, the subjects were exposed to acute stress in the form of a 2 min public speech. Salivary flow rate and total protein was measured. The physiological stress marker cortisol was analyzed using enzyme-linked immunosorbent assay. To determine the subjects' psychological stress reaction, the State-Trait-Anxiety Inventory State questionnaire (STAI data were obtained. The subjects were divided into stress subgroup (S1 (psychological reactivity, stress subgroup (S2 (psychological and physiological reactivity and a control group. The area under the curve for salivarycortisol concentration and STAI-State scores were calculated. All data underwent statistical analysis using one-way analysis of variance. RESULTS: Immediately after stress exposure, all participants exhibited a psychological stress reaction. Stress exposure did not change the salivary flow rate. Only 69% of the subjects continued to display a physiological stress reaction 20 minutes after the public talk. There was no significant change in the salivary flow rate during the psychological and the physiological stress reaction phases relative to the baseline. CONCLUSIONS: Acute stress has no impact on the salivary flow rate; however, there may be other responses through salivary proteins that are increased with the acute stress stimuli. Future studies are needed to examine

  1. Reevaluating the "subjective weathering" hypothesis: subjective aging, coping resources, and the stress process.

    Science.gov (United States)

    Benson, Janel E

    2014-03-01

    The subjective weathering model contends that subjective aging is a key component of the stress process. This study reevaluates and extends this model by considering how adaptive capacities influence subjective aging and depressive symptoms in late adolescence and young adulthood. Using longitudinal data from the National Longitudinal Study of Adolescent Health (n = 7,230), I investigate how earlier stressors and coping resources contribute to older age identities (ages 18-22) and how these self-perceptions influence subsequent depressive symptoms (ages 25-29). The results show that subjective weathering alone does not lead to depressive symptoms; the critical issue is the level of psychosocial maturity that accompanies an older age identity. Those with high levels of psychosocial maturity, regardless of subjective age, were least likely to exhibit depressive symptoms. These results demonstrate that psychosocial maturity is an important adaptive resource that can shield young adults from the negative effects of "subjective weathering" or growing up fast.

  2. 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

  3. Evaluation for Intensity of Stress in Lesson using Heart Rate Variability Detected by Simultaneously Measurement

    Science.gov (United States)

    Horiguchi, Ayaka; Takatsu, Hiroaki; Ohno, Wataru; Ozeki, Osamu

    We studied the evaluation for the intensity of stress of students in lesson using heart rate variability. Heart rate of many students were measured simultaneously by developed portable measurement systems. Heart rate variability data suggests that many students have more stress in normal dictation lesson then video lesson using difficult subject.

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

    Science.gov (United States)

    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].

  5. Neutrophil Ingestion Rate Of Nitroblue Tetrazolium In Subjects With ...

    African Journals Online (AJOL)

    Objectives: This study was designed to assess the WBC count, absolute neutrophil count, CD4 +T cell count and neutrophil ingestion rate of nitroblue tetrazolium in subjects with Malaria and HIV Co-morbidity. Method and materials: 134 participants were recruited and group as follow: Symptomatic HIV infected participants ...

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

    Science.gov (United States)

    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.

  7. Does Ramadan fasting affect expiratory flow rates in healthy subjects?

    Science.gov (United States)

    Subhan, Mirza M F; Siddiqui, Qamar A; Khan, Mohammed N; Sabir, Salman

    2006-11-01

    To assess whether Ramadan fasting affects the expiratory flow rates in healthy subjects, and to know if these effects correlate to a change in other variables. This unmatched case-control longitudinal study includes 46 non-smoking healthy subjects who undertook lung function testing at the Aga Khan University, Pakistan. Expiratory flow rates and body mass were measured in 3 Islamic months, corresponding to November 2001 to January 2002. There was a significant reduction in body mass in Ramadan compared to pre and post Ramadan. No significant changes in expiratory flows were seen during Ramadan as compared to the pre Ramadan period. However, forced expiratory flow rates at 75% of vital capacity (FEF(75)) and between 75% and 85% of vital capacity (FEF(75-85)) showed a significant increase in the post Ramadan period compared to Ramadan. Changes in FEF(75) were negatively correlated to changes in body mass between Ramadan and post Ramadan. This study shows that Ramadan fasting will not affect expiratory flow rates in healthy subjects. Post Ramadan values did show an increase in FEF(75) and FEF(75-85), possibly due to changes in body water and fat content. The reductions in body mass were most probably due to lack of nutrition and not dehydration as the fasts were performed in winter. Collection of reference values or early phase clinical trials measuring expiratory flow rates should not be affected by Ramadan fasting.

  8. Cardiovagal modulation, oxidative stress, and cardiovascular risk factors in prehypertensive subjects: cross-sectional study.

    Science.gov (United States)

    Thiyagarajan, Ramkumar; Pal, Pravati; Pal, Gopal Krushna; Subramanian, Senthil Kumar; Bobby, Zachariah; Das, Ashok Kumar; Trakroo, Madanmohan

    2013-07-01

    Hypertension, one of the modifiable risk factors for cardiovascular disease (CVD), is known to be associated with increased oxidative stress and reduced cardiovagal modulation. Similar to hypertension, prehypertension is associated with increased risk of adverse cardiovascular (CV) events. We planned this study to find the association between prehypertension, cardiovagal modulation, oxidative stress, and associated CV risk factors. We recruited 178 subjects through hypertension screening camps conducted in Puducherry, India. Subjects were grouped into prehypertensive (n = 97) and normotensive (n = 81) groups. They were further subdivided, based on age, as young (20-39 years) and middle-aged (40-60 years) adults. We measured basal physiological parameters, heart rate variability, oxidative stress (thiobarbituric acid reactive substance and total antioxidant capacity (TAC)), and CV risk factors. We found significant increase in oxidative stress in prehypertensive subjects of both age groups but the cardiovagal modulation decreased significantly in young prehypertensive subjects when compared with normotensive subjects. Correlation of TAC with root mean square of the sum of successive R wave to R wave (RR) interval differences (RMSSD), a cardiovagal modulation parameter (r = 0. 437; P risk factors. The correlation between MAP and RMSSD (r = 0.199; P = 0.009) was reduced after adjusting for CV risk factors. Prehypertension in young adults is associated with increased oxidative stress and altered cardiovagal modulation. The risk factors for CVDs in prehypertensive young adults were found to be equivalent to that of middle-aged adults who are in the twilight zone for developing CV dysfunctions.

  9. 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.

  10. 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.

  11. 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.

  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. 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

    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...... significantly decreased under drought and combined stress as compared to control. The tomato 'Arvento' was more affected by heat stress than 'LA1994' and 'LA2093' due to significant decreases in shoot dry weight, chlorophyll a and carotenoid content, starch content and NPQ (non-photochemical quenching) only...... in 'Arvento' under heat treatment. By comparison, the two heat-tolerant tomatoes were more affected by drought stress compared to 'Arvento' as shown by small stomatal and pore area, decreased sucrose content, ΦPSII (quantum yield of photosystem II), ETR (electron transport rate) and qL (fraction of open PSII...

  14. 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

  15. A comparative study of pulse rate variability and heart rate variability in healthy subjects.

    Science.gov (United States)

    Wong, Jih-Sen; Lu, Wan-An; Wu, Kung-Tai; Liu, Margaret; Chen, Gau-Yang; Kuo, Cheng-Deng

    2012-04-01

    Both heart rate variability (HRV) and pulse rate variability (PRV) are noninvasive means for the assessment of autonomic nervous control of the heart. However, it is not settled whether or not the PRV obtained from either hand can be the surrogate of HRV. The HRV measures obtained from electrocardiographic signals and the PRV measures obtained from the pulse waves recorded from the index fingers of both hands were compared in normal subjects by using linear regression analysis and Bland and Altman method. Highly significant correlations (P heart rate and ultra-low frequency power (ULFP). The PRV of either hand is close to, but not the same as the HRV in healthy subjects. The HRV, right PRV and left PRV are not surrogates of one another in normal subjects except heart rate and ULFP. Since HRV is generally accepted as the standard method for the assessment of the autonomic nervous modulation of a subject, the PRV of either hand may not be suitable for the assessment of the cardiac autonomic nervous modulation of the subject.

  16. Effects of lithium on oxidative stress parameters in healthy subjects.

    Science.gov (United States)

    Khairova, Rushaniya; Pawar, Rohit; Salvadore, Giacomo; Juruena, Mario F; de Sousa, Rafael T; Soeiro-de-Souza, Márcio G; Salvador, Mirian; Zarate, Carlos A; Gattaz, Wagner F; Machado-Vieira, Rodrigo

    2012-03-01

    Increased neuronal oxidative stress (OxS) induces deleterious effects on signal transduction, structural plasticity and cellular resilience, mainly by inducing lipid peroxidation in membranes, proteins and genes. Major markers of OxS levels include the thiobarbituric acid reactive substances (TBARS) and the enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase. Lithium has been shown to prevent and/or reverse DNA damage, free-radical formation and lipid peroxidation in diverse models. This study evaluates OxS parameters in healthy volunteers prior to and following lithium treatment. Healthy volunteers were treated with lithium in therapeutic doses for 2-4 weeks. Treatment with lithium in healthy volunteers selectively altered SOD levels in all subjects. Furthermore, a significant decrease in the SOD/CAT ratio was observed following lithium treatment, which was associated with decreased OxS by lowering hydrogen peroxide levels. This reduction in the SOD/CAT ratio may lead to lower OxS, indicated primarily by a decrease in the concentration of cell hydrogen peroxide. Overall, the present findings indicate a potential role for the antioxidant effects of lithium in healthy subjects, supporting its neuroprotective profile in bipolar disorder (BD) and, possibly, in neurodegenerative processes.

  17. Stress augments food 'wanting' and energy intake in visceral overweight subjects in the absence of hunger.

    Science.gov (United States)

    Lemmens, Sofie G; Rutters, Femke; Born, Jurriaan M; Westerterp-Plantenga, Margriet S

    2011-05-03

    Stress may induce eating in the absence of hunger, possibly involving changes in food reward, i.e. 'liking' and 'wanting'. The objective of this study was to assess the effects of acute psychological stress on food reward, and on energy intake, in visceral overweight (VO) vs. normal weight (NW) subjects. Subjects (27 NW, age=26 ± 9 yrs, BMI=22 ± 2 kg/m²; 15 VO, age=36 ± 12 yrs, BMI=28 ± 1 kg/m²) came to the university twice, fasted, for either a rest or stress condition (randomized cross-over design). Per test-session 'liking' and 'wanting' for 72 items divided in six categories (bread, filling, drinks, dessert, snacks, and stationery (control)) were measured twice, each time followed by a wanted meal. Appetite profile (visual analogue scales, VAS), heart rate, mood state and level of anxiety (POMS/STAI questionnaires) were measured. High hunger and low satiety (64 ± 19, 22 ± 20 mmVAS) confirmed the fasted state. Elevated heart rate, anger and confusion scores (p ≤ 0.03) confirmed the stress vs. rest condition. Consumption of the first meal decreased hunger, increased satiety, and decreased ranking of 'liking' of bread vs. increased ranking of 'liking' of the control (psnacks, energy intake, carbohydrate and fat intake for the second meal stress vs. rest relatively increased in VO vs. decreased in NW (pstress vs. rest VO showed a 6 ± 9% increase in percentage of daily energy requirements consumed over the two meals (p=0.01). To conclude, visceral overweight subjects showed stress-induced food intake in the absence of hunger, resulting in an increased energy intake. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. Exhaustive exercise modifies oxidative stress in smoking subjects.

    Science.gov (United States)

    Gochman, Einat; Reznick, Abraham Z; Avizohar, Ophir; Ben-Amotz, Ami; Levy, Yishai

    2007-06-01

    Exhaustive exercise is associated with increased metabolic rate and accelerated generation of reactive oxygen species. Cigarette smoke also contains oxidants that may participate in the development of atherosclerosis. However, data on the association between exercise and smoking are sparse. A homogenous group of 30 young men (15 smokers and 15 nonsmokers; mean age, 23.7 +/- 2.6 years), healthy, trained subjects, were assessed before and after a standard maximal exercise test. Exercise led to increased protein oxidation (carbonyl assay) in both smokers (+17.7%, P insults probably due to lower antioxidant capacity.

  19. The influence of negative mood on heart rate complexity measures and baroreflex sensitivity in healthy subjects.

    Science.gov (United States)

    Köbele, Ralf; Koschke, Mandy; Schulz, Steffen; Wagner, Gerd; Yeragani, Shravya; Ramachandraiah, Chaitra T; Voss, Andreas; Yeragani, Vikram K; Bär, Karl-Jürgen

    2010-01-01

    Decreased cardiac vagal function is linked with increased cardiac mortality and depression is associated with decreased heart rate variability. We have previously shown that the Mood Induction Procedure (MIP) in healthy subjects alters pain perception and thalamic activity during pain perception. To study the effect of negative emotion on heart rate variability and complexity measures as well as on baroreceptor sensitivity, as these parameters reflect cardiac autonomic function. We studied 20 healthy female controls before and after neutral MIP and 20 healthy female subjects before and after negative MIP. We investigated measures of valence of mood, heart rate variability and complexity and the baroreceptor sensitivity index. While there was a significant difference in the valence of mood between the neutral and the negative effect condition, there were no significant differences in any of the heart rate or baroreceptor sensitivity measures between the two groups. Our findings did not show any significant influence of acute negative MIP on heart rate variability and complexity measures and baroreceptor sensitivity, even though depressive disorder and stress are associated with decreased heart rate variability. These findings are discussed in the context of clinical depression and anxiety and the increased risk for cardiac mortality. In contrast to the presented results here, we have previously shown that MIP in healthy subjects alters pain perception and thalamic activity.

  20. Effect of Tongkat Ali on stress hormones and psychological mood state in moderately stressed subjects

    OpenAIRE

    Talbott, Shawn M; Talbott, Julie A; George, Annie; Pugh, Mike

    2013-01-01

    Background Eurycoma longifolia is a medicinal plant commonly called tongkat ali (TA) and ?Malaysian ginseng.? TA roots are a traditional ?anti-aging? remedy and modern supplements are intended to improve libido, energy, sports performance and weight loss. Previous studies have shown properly-standardized TA to stimulate release of free testosterone, improve sex drive, reduce fatigue, and improve well-being. Methods We assessed stress hormones and mood state in 63 subjects (32 men and 31 women...

  1. Sternal Pulse Rate Variability Compared with Heart Rate Variability on Healthy Subjects

    DEFF Research Database (Denmark)

    Chreiteh, Shadi; Belhage, Bo; Hoppe, Karsten

    2014-01-01

    The heart rate variability (HRV) is a commonly used method to quantify the sympathetic and the parasympathetic modulation of the heart rate. HRV is mainly conducted on electrocardiograms (ECG). However, the use of photoplethysmography (PPG) as a marker of the autonomic tone is emerging....... In this study we investigated the feasibility of deriving pulse rate variability (PRV) using PPG signals recorded by a reflectance PPG sensor attached to the chest bone (sternum) and comparing it to HRV. The recordings were conducted on 9 healthy subjects being in a relaxed supine position and under forced...... the parameters (r > 0:95 with p using sternal PPG can be an alternative to HRV analysis on healthy subjects at rest....

  2. Sternal pulse rate variability compared with heart rate variability on healthy subjects.

    Science.gov (United States)

    Chreiteh, Shadi S; Belhage, Bo; Hoppe, Karsten; Branebjerg, Jens; Thomsen, Erik V

    2014-01-01

    The heart rate variability (HRV) is a commonly used method to quantify the sympathetic and the parasympathetic modulation of the heart rate. HRV is mainly conducted on electrocardiograms (ECG). However, the use of photo-plethysmography (PPG) as a marker of the autonomic tone is emerging. In this study we investigated the feasibility of deriving pulse rate variability (PRV) using PPG signals recorded by a reflectance PPG sensor attached to the chest bone (sternum) and comparing it to HRV. The recordings were conducted on 9 healthy subjects being in a relaxed supine position and under forced respiration, where the subjects were asked to breathe following a visual scale with a rate of 27 breaths/min. HRV parameters such as the mean intervals (meanNN), the standard deviation of intervals (SDNN), the root mean square of difference of successive intervals (RMSSD), and the proportion of intervals differing more than 50 ms (pNN50) were calculated from the R peak-to-R peak (R-R) and pulse-to-pulse (P-P) intervals. In the frequency domain the low and high frequency ratio of the power spectral density (LF/HF) was also computed. The Pearson correlation coefficient showed significant correlation for all the parameters (r > 0.95 with p healthy subjects at.

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

    African Journals Online (AJOL)

    Background: Oxidative stress is known to play a role in the pathophysiology of metabolic syndrome and its components. Racial differences may exist in the level of markers of oxidative stress and antioxidants in patients with metabolic syndrome. Aim: The aim of this study was to determine the oxidative stress and ...

  4. 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

  5. Attenuated metoclopramide-induced vascular hyperreactivity to cold stress in athletic subjects.

    Science.gov (United States)

    Blanco, M; Gómez, J; Blanco, G; Negrín, C; Velasco, M

    1998-11-01

    We have previously reported a metoclopramide-induced vascular hyperreactivity to the cold pressor test (CPT) in normotensive and hypertensive subjects. The present study was designed to determine whether the state of physical training influences the cardiovascular responses to the CPT in normotensive subjects under metoclopramide (MTC) treatment. In 20 untrained subjects and 32 athletes (football players and runners), the blood pressure and heart rate responses to the CPT were studied after a 30-minute infusion of MTC (7.5 microg/kg per minute) and two placebo periods, before and after MTC, with 5% glucose solution. Under placebo conditions, the CPT produced significant increases of systolic blood pressure (SBP) in the untrained subjects and the runners, but not in the football players (17.2, 17.8, and 6.5 mm Hg for untrained subjects, runners, and football players, respectively). The runners responded with a lesser increase in diastolic blood pressure (DBP) during the CPT than did the others (15.8, 17.9, and 18.2 mm Hg for runners, untrained subjects, and football players, respectively). In the presence of MTC, the CPT induced a larger increase in blood pressure (SBP/DBP) in the untrained subjects (21.4/24.1 mm Hg) than in the football players (10/18.7 mm Hg) and runners (18.7/13.9 mm Hg). MTC diminished the hyperreactivity responses to the CPT in the trained subjects (41 and 56% for football players and runners, respectively). Our conclusions are as follows: (1) Vascular responses to cold stress are attenuated in athletic subjects compared with untrained subjects. (2) The metoclopramide-induced vascular hyperreactivity, formerly reported for normotensive and hypertensive subjects, seems to be absent in trained subjects. (3) It is suggested that a probable dopaminergic system adaptation occurs during exercise.

  6. 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.

  7. 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. PMID:25250009

  8. The use of subjective rating of exertion in Ergonomics.

    Science.gov (United States)

    Capodaglio, P

    2002-01-01

    In Ergonomics, the use of psychophysical methods for subjectively evaluating work tasks and determining acceptable loads has become more common. Daily activities at the work site are studied not only with physiological methods but also with perceptual estimation and production methods. The psychophysical methods are of special interest in field studies of short-term work tasks for which valid physiological measurements are difficult to obtain. The perceived exertion, difficulty and fatigue that a person experiences in a certain work situation is an important sign of a real or objective load. Measurement of the physical load with physiological parameters is not sufficient since it does not take into consideration the particular difficulty of the performance or the capacity of the individual. It is often difficult from technical and biomechanical analyses to understand the seriousness of a difficulty that a person experiences. Physiological determinations give important information, but they may be insufficient due to the technical problems in obtaining relevant but simple measurements for short-term activities or activities involving special movement patterns. Perceptual estimations using Borg's scales give important information because the severity of a task's difficulty depends on the individual doing the work. Observation is the most simple and used means to assess job demands. Other evaluations integrating observation are the followings: indirect estimation of energy expenditure based on prediction equations or direct measurement of oxygen consumption; measurements of forces, angles and biomechanical parameters; measurements of physiological and neurophysiological parameters during tasks. It is recommended that determinations of performances of occupational activities assess rating of perceived exertion and integrate these measurements of intensity levels with those of activity's type, duration and frequency. A better estimate of the degree of physical activity

  9. Academic stress, power motivation, and decrease in secretion rate of salivary secretory immunoglobulin A.

    Science.gov (United States)

    Jemmott, J B; Borysenko, J Z; Borysenko, M; McClelland, D C; Chapman, R; Meyer, D; Benson, H

    1983-06-25

    The effect of academic stress on immune function, as measured by the rate of secretion of salivary secretory immunoglobulin A (s-IgA), was studied prospectively in 64 first-year dental school students. Perceived stress and s-IgA secretion rate were measured five times--during an initial low-stress period, three high-stress periods coinciding with major examinations, and a final low-stress period. The s-IgA secretion rate was significantly lower in high-stress than low-stress periods for the whole group. In addition, personality characteristics differentiated patterns of s-IgA secretion rates. Students characterised by a great need to establish and maintain warm personal relationships secreted more s-IgA at each point than did all other subjects. The s-IgA secretion rates of those with a high inhibited need for power continued to decline through the final low-stress period rather than recovering as in all other subjects.

  10. Effect of Tongkat Ali on stress hormones and psychological mood state in moderately stressed subjects.

    Science.gov (United States)

    Talbott, Shawn M; Talbott, Julie A; George, Annie; Pugh, Mike

    2013-05-26

    Eurycoma longifolia is a medicinal plant commonly called tongkat ali (TA) and "Malaysian ginseng." TA roots are a traditional "anti-aging" remedy and modern supplements are intended to improve libido, energy, sports performance and weight loss. Previous studies have shown properly-standardized TA to stimulate release of free testosterone, improve sex drive, reduce fatigue, and improve well-being. We assessed stress hormones and mood state in 63 subjects (32 men and 31 women) screened for moderate stress and supplemented with a standardized hot-water extract of TA root (TA) or Placebo (PL) for 4 weeks. Analysis of variance (ANOVA) with significance set at p sleep deprivation, and exercise training.

  11. Life Stress: Related Symptoms, Subjective Appraisal and Coping Styles.

    Science.gov (United States)

    Kantner, James E.; And Others

    Stress and its influence upon physiological and emotional functioning has been well documented in research literature. In order to extend this research to study the relationship between accumulated life stress, symptoms, and coping responses, 202 college graduates and undergraduates, (144 females and 58 males) responded to three self-report…

  12. Stress, sense of coherence and subjective health in adolescents aged 13-18 years.

    Science.gov (United States)

    Moksnes, Unni K; Espnes, Geir A

    2017-06-01

    This study investigated the relationships between sex, age, stress and sense of coherence (SOC) and each of self-rated health (SRH) and subjective health complaints (SHCs) in adolescents. The study was based on a cross-sectional sample of 1239 adolescents aged 13-18 years. The participants reported scores on a questionnaire, including 12 items assessing SHC, the 13-item version of the Orientation to Life Questionnaire and the 30-item Adolescent Stress Questionnaire. Data were analysed with descriptive, comparative and hierarchical multiple regression analyses. Boys scored significantly higher on SRH than girls, whereas girls scored higher on SHCs. In the multivariate model, stress was significantly associated with SHCs, but not with SRH. SOC was significantly positively related to SRH and negatively related to SHC; the associations were significantly stronger for girls than for boys. A significant moderation effect (protective role) of SOC was found on the relation between stress and SHC. No causal conclusion was possible, but the findings may be used as a basis for further investigation of the role of stress and SOC in longitudinal studies and intervention studies.

  13. 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.

  14. Vitamin C and common cold incidence: a review of studies with subjects under heavy physical stress.

    Science.gov (United States)

    Hemilä, H

    1996-07-01

    Several studies have observed an increased risk of respiratory infections in subjects doing heavy physical exercise. Vitamin C has been shown to affect some parts of the immune system, and accordingly it seems biologically conceivable that it could have effects on the increased incidence of respiratory infections caused by heavy physical stress. In this report the results of three placebo-controlled studies that have examined the effect of vitamin C supplementation on common cold incidence in subjects under acute physical stress are analyzed. In one study the subjects were school-children at a skiing camp in the Swiss Alps, in another they were military troops training in Northern Canada, and in the third they were participants in a 90 km running race. In each of the three studies a considerable reduction in common cold incidence in the group supplemented with vitamin C(0.6-1.0 g/day) was found. The pooled rate ratio (RR) of common cold infections in the studies was 0.50 (95% CI: 0.35-0.69) in favour of vitamin C groups. Accordingly, the results of the three studies suggest that vitamin C supplementation may be beneficial for some of the subjects doing heavy exercise who have problems with frequent upper respiratory infections.

  15. A new rate-dependent unidirectional composite model - Application to panels subjected to underwater blast

    Science.gov (United States)

    Wei, Xiaoding; de Vaucorbeil, Alban; Tran, Phuong; Espinosa, Horacio D.

    2013-06-01

    In this study, we developed a finite element fluid-structure interaction model to understand the deformation and failure mechanisms of both monolithic and sandwich composite panels. A new failure criterion that includes strain-rate effects was formulated and implemented to simulate different damage modes in unidirectional glass fiber/matrix composites. The laminate model uses Hashin's fiber failure criterion and a modified Tsai-Wu matrix failure criterion. The composite moduli are degraded using five damage variables, which are updated in the post-failure regime by means of a linear softening law governed by an energy release criterion. A key feature in the formulation is the distinction between fiber rupture and pull-out by introducing a modified fracture toughness, which varies from a fiber tensile toughness to a matrix tensile toughness as a function of the ratio of longitudinal normal stress to effective shear stress. The delamination between laminas is modeled by a strain-rate sensitive cohesive law. In the case of sandwich panels, core compaction is modeled by a crushable foam plasticity model with volumetric hardening and strain-rate sensitivity. These constitutive descriptions were used to predict deformation histories, fiber/matrix damage patterns, and inter-lamina delamination, for both monolithic and sandwich composite panels subjected to underwater blast. The numerical predictions were compared with experimental observations. We demonstrate that the new rate dependent composite damage model captures the spatial distribution and magnitude of damage significantly more accurately than previously developed models.

  16. Confidentiality and Professional Affiliation Effects on Subject Ratings of Interviewers.

    Science.gov (United States)

    Drake, David W.; And Others

    The purpose of this research was to study the effects of different statements regarding confidentiality (absolute; limited; nondirective) on subject impressions of interviewers. In addition, the professional affiliation of the interviewer was manipulated (psychologist, minister/pastoral counselor, social worker) to assess potential influence of…

  17. Altered Pain Perception and Fear-Learning Deficits in Subjects With Posttraumatic Stress Disorder.

    Science.gov (United States)

    Jenewein, Josef; Erni, Jeannine; Moergeli, Hanspeter; Grillon, Christian; Schumacher, Sonja; Mueller-Pfeiffer, Christoph; Hassanpour, Katayun; Seiler, Annina; Wittmann, Lutz; Schnyder, Ulrich; Hasler, Gregor

    2016-12-01

    There is growing evidence that fear-learning abnormalities are involved in the development of posttraumatic stress disorder (PTSD) and chronic pain. More than 50% of PTSD patients suffer from chronic pain. This study aimed to examine the role of fear-learning deficits in the link between pain perception and PTSD. We included 19 subjects with PTSD and 21 age- and sex-matched healthy control subjects in a fear-conditioning experiment. The conditioned stimulus (CS) consisted of visual signs flashed upon a screen in front of each subject. The unconditioned stimulus was either a low or high temperature impulse delivered through a thermal contact thermode on the subjects' hand. A designation of 'CS-' was assigned to CS always followed by nonpainful low-temperature stimuli; a designation of 'CS+' was given to CS that were randomly followed by either a low or a more painful high temperature. Skin conductance was used as a physiological marker of fear. In healthy control subjects, CS+ induced more fear than CS-, and a low-temperature stimulus induced less subjective pain after CS- than after CS+. PTSD subjects failed to demonstrate such adaptive conditioning. Fear ratings after CS presentation were significantly higher in the PTSD group than in the control group. There were significant interaction effects between group and the type of CS on fear and pain ratings. Fear-learning deficits are a potentially promising, specific psychopathological factor in altered pain perception associated with PTSD. Deficits in safety learning may increase fear and, consequently, pain sensations. These findings may contribute to elucidating the pathogenesis behind the highly prevalent comorbidity that exists between PTSD and pain disorders, and to developing new treatments. This study provides new insights into the pathogenesis of chronic pain in patients with PTSD. The findings may help to develop new treatment strategies for this highly prevalent comorbidity in PTSD. Copyright © 2016

  18. Gender differences in response to emotional stress: an assessment across subjective, behavioral, and physiological domains and relations to alcohol craving.

    Science.gov (United States)

    Chaplin, Tara M; Hong, Kwangik; Bergquist, Keri; Sinha, Rajita

    2008-07-01

    Women and men are at risk for different types of stress-related disorders, with women at greater risk for depression and anxiety and men at greater risk for alcohol-use disorders. The present study examines gender differences in emotional and alcohol craving responses to stress that may relate to this gender divergence in disorders. Healthy adult social drinkers (27 men, 27 women) were exposed to individually developed and calibrated stressful, alcohol-related, and neutral-relaxing imagery, 1 imagery per session, on separate days and in random order. Subjective emotions, behavioral/bodily responses, cardiovascular arousal [heart rate (HR), blood pressure (BP)], and self-reported alcohol craving were assessed. Women reported and displayed greater sadness and anxiety following stress than men and men had greater diastolic BP response than women. No gender differences in alcohol craving, systolic BP or HR were observed. Subjective, behavioral, and cardiovascular measures were correlated in both genders. However, for men, but not women, alcohol craving was associated with greater subjective emotion and behavioral arousal following stress and alcohol cues. These data suggest that men and women respond to stress differently, with women experiencing greater sadness and anxiety, while men show a greater integration of reward motivation (craving) and emotional stress systems. These findings have implications for the gender-related divergence in vulnerability for stress-related disorders, with women at greater risk for anxiety and depression than men, and men at greater risk for alcohol-use disorders than women.

  19. 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.

  20. Integrative aspects of the relationship between stress and heart rate variability

    Directory of Open Access Journals (Sweden)

    Suelen Moraes de Lorenzo

    2013-12-01

    Full Text Available The literature indicates stress as a response of the organism to a stimulation that requires enormous efforts to adapt to the changes in the environment and the body. When an individual is subjected to stress, the autonomic nervous system is triggered, the sympathetic pathway is activated, and the parasympathetic system is suppressed, which exerts several effects on the cardiovascular system and affects heart rate variability. This research aimed to conduct a literature review to find and analyze the studies that address clearly the implications of stress on heart rate variability. The methodology employed was an active search in the databases SciELO, PubMed and Lilacs. The results were five articles, most of which suggest a relationship between stress and heart rate variability. We observed that the majority of the studies indicated a strong association between stress and cardiac autonomic activity. The stress is present in the daily activities of the population, especially in labor. The subject is vast, however, were observed in the references the effects of stress on the body making it vulnerable to diseases. Thus, this information may contribute to the aid of preventive strategies against stress and diseases of the cardiovascular system.

  1. Heart Rate and Stress in a College Setting

    Science.gov (United States)

    Elwess, Nancy L.; Vogt, F. Daniel

    2005-01-01

    Conditions producing stress are present in all colleges and universities. In this paper we report on an investigation utilizing heart rate as an indicator of stress in students when participating in activities encountered in a college classroom or laboratory. The activities included presenting an oral report, taking an exam, and participating in a…

  2. Stress and Performance: Effects of Subjective Work Load and Time Urgency.

    Science.gov (United States)

    Friend, Kenneth E.

    1982-01-01

    Measured subjective work load, time urgency, and other stress/motivation variables for management personnel taking a demanding problem-solving exam. Data suggest increases in psychological stresses like subjectively high work load and time urgency uniformly impair performance across the whole range of these variables. (Author)

  3. 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

  4. 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

  5. Objective Versus Subjective Measurement of Stress and Social Support: Combat-Related Reactions.

    Science.gov (United States)

    Solomon, Zahava; And Others

    1987-01-01

    Studied combat intensity, social support, and related stress reactions among soldiers who fought in the 1982 Israeli-Lebanon War, comparing those who experienced combat stress reaction (N=382) and those who did not (N=344). Subjective indicators were found to be stronger predictors than were objective indicators. Combat stress reaction was clearly…

  6. Low-velocity impact response of laminated beams subjected to initial stresses

    Science.gov (United States)

    Sankar, B. V.; Sun, C. T.

    1985-01-01

    Finite element procedures are used in conjunction with a numerical algorithm to compute the impact response of a graphite-epoxy laminated beam subjected to tensile initial stresses. The effect of initial stresses on the contact duration, impact force, coefficient of restitution, and bending and shear stresses are discussed. The analytically computed contact force history and strain response are compared with some experimental results.

  7. 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.

  8. Managing cable thermal stress through predictive ratings

    OpenAIRE

    Huang, R.; Pilgrim, J.A.; Lewin, P.L.; Scott, D.; Morrice, D.

    2015-01-01

    The majority of high voltage cables are sized and operated by a continuous current rating which is based on the worst-case assumptions. However, the load on the cables themselves may vary significantly depending upon the time and season. In this paper, a dynamic thermal model for a cable in air installation is built using the finite difference method. The real-time load current and ambient conditions are accessible to allow improved cable modelling. This model is then used to support the rati...

  9. Interaction of surface cracks subjected to non-uniform distributions of stress

    OpenAIRE

    Coules, H.E.

    2017-01-01

    Closely-spaced surface cracks in structures interact with each other when subjected to load. The degree of interaction depends strongly on the distribution of stress that is applied. In pressure boundary components, thermal shock, residual stress and global bending can all cause load distributions that are non-uniform through the wall thickness. A wide range of crack pairs subject to various non-uniform stress distributions have been modelled using finite element analysis. Cracks sometimes in...

  10. Turbulent oscillating channel flow subjected to a wind stress

    NARCIS (Netherlands)

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

    2008-01-01

    The Westerschelde estuary in the Netherlands is characterized by a strong tidal driven flow with typical velocities in the range of 0.2 to 1 m/s. In addition to the tides the wind (5 m/s) exerts a stress at the free surface driving the upper fluid layers. To investigate this flow we performed

  11. 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.

  12. Diallel analysis in white oat cultivars subjected to water stress.

    Directory of Open Access Journals (Sweden)

    Guilherme Ribeiro

    2011-01-01

    Full Text Available The goal of this work was to determine the combining ability of three white oat parental genotypes (UPF 18, URS21and URS 22 and to estimate the heterosis of F1 hybrids in two conditions, with and without water stress. The results indicate a largeeffect of the environment on the evaluated characters (cycle, leaf area, plant stature, grain yield per plant, main panicle weight andnumber of grains of the main panicle. The condition without stress was the most efficient for the selection of superior genotypes.Based on the general and specific combining ability, the cultivar URS 22 was shown to be indicated for cycle and stature reduction,while UPF 18 lead to increases in leaf area, main panicle weight and number of grains of the main panicle. The specific cross URS22 x URS 21 was the best for the selection of superior genotypes.

  13. 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.

  14. 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.

  15. Objective and subjective memory ratings in cannabis-dependent adolescents.

    Science.gov (United States)

    McClure, Erin A; Lydiard, Jessica B; Goddard, Scott D; Gray, Kevin M

    2015-01-01

    Cannabis is the most widely used illicit substance worldwide, with an estimated 160 million users. Among adolescents, rates of cannabis use are increasing, while the perception of detrimental effects of cannabis use is declining. Difficulty with memory is one of the most frequently noted cognitive deficits associated with cannabis use, but little data exist exploring how well users can identify their own memory deficits, if present. The current secondary analysis sought to characterize objective verbal and visual memory performance via a neurocognitive battery in cannabis-dependent adolescents enrolled in a pharmacotherapeutic cannabis cessation clinical trial (N = 112) and compare this to a single self-reported item assessing difficulties with memory loss. Exploratory analyses also assessed dose-dependent effects of cannabis on memory performance. A small portion of the study sample (10%) endorsed a "serious problem" with memory loss. Those participants reporting "no problem" or "serious problem" scored similarly on visual and verbal memory tasks on the neurocognitive battery. Exploratory analyses suggested a potential relationship between days of cannabis use, amount of cannabis used, and gender with memory performance. This preliminary and exploratory analysis suggests that a sub-set of cannabis users may not accurately perceive difficulties with memory. Further work should test this hypothesis with the use of a control group, comprehensive self-reports of memory problems, and adult populations that may have more years of cannabis use and more severe cognitive deficits. © American Academy of Addiction Psychiatry.

  16. Delayed seismicity rate changes controlled by static stress transfer

    Science.gov (United States)

    Kroll, Kayla A.; Richards-Dinger, Keith B.; Dieterich, James H.; Cochran, Elizabeth S.

    2017-01-01

    On 15 June 2010, a Mw5.7 earthquake occurred near Ocotillo, California, in the Yuha Desert. This event was the largest aftershock of the 4 April 2010 Mw7.2 El Mayor-Cucapah (EMC) earthquake in this region. The EMC mainshock and subsequent Ocotillo aftershock provide an opportunity to test the Coulomb failure hypothesis (CFS). We explore the spatiotemporal correlation between seismicity rate changes and regions of positive and negative CFS change imparted by the Ocotillo event. Based on simple CFS calculations we divide the Yuha Desert into three subregions, one triggering zone and two stress shadow zones. We find the nominal triggering zone displays immediate triggering, one stress shadowed region experiences immediate quiescence, and the other nominal stress shadow undergoes an immediate rate increase followed by a delayed shutdown. We quantitatively model the spatiotemporal variation of earthquake rates by combining calculations of CFS change with the rate-state earthquake rate formulation of Dieterich (1994), assuming that each subregion contains a mixture of nucleation sources that experienced a CFS change of differing signs. Our modeling reproduces the observations, including the observed delay in the stress shadow effect in the third region following the Ocotillo aftershock. The delayed shadow effect occurs because of intrinsic differences in the amplitude of the rate response to positive and negative stress changes and the time constants for return to background rates for the two populations. We find that rate-state models of time-dependent earthquake rates are in good agreement with the observed rates and thus explain the complex spatiotemporal patterns of seismicity.

  17. Association between subjective and cortisol stress response depends on the menstrual cycle phase.

    Science.gov (United States)

    Duchesne, Annie; Pruessner, Jens C

    2013-12-01

    The relation between the physiologic and subjective stress responses is inconsistently reported across studies. Menstrual cycle phases variations have been found to influence the psychophysiological stress response; however little is known about possible cycle phase differences in the relationship between physiological and subjective stress responses. This study examined the effect of menstrual cycle phase in the association between subjective stress and physiological response. Forty-five women in either the follicular (n=21) or the luteal phase of the menstrual cycle were exposed to a psychosocial stress task. Salivary cortisol, cardiovascular, and subjective stress were assessed throughout the experiment. Results revealed a significant group difference in the association between peak levels of cortisol and post task subjective stress. In women in the follicular phase a negative association was observed (r(2)=0.199, p=0.04), while this relation was positive in the group of women in the luteal phase (r(2)=0.227, p=0.02). These findings suggest a possible role of sex hormones in modulating the cortisol stress response function in emotion regulation. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  18. Residual stress redistribution in shot peened samples subject to mechanical loading

    Energy Technology Data Exchange (ETDEWEB)

    Buchanan, Dennis J., E-mail: dennis.buchanan@udri.udayton.edu [University of Dayton Research Institute, 300 College Park, Dayton, OH 45469-0020 (United States); John, Reji [Materials and Manufacturing Directorate, Air Force Research Laboratory (AFRL/RXCM), Wright-Patterson Air Force Base, OH 45433-7817 (United States)

    2014-10-06

    Shot peening is a well-established surface treatment process that imparts large compressive residual stresses onto the surface and at shallow depths to retard initiation and growth of fatigue cracks. The plastic deformation developed during the surface treatment sets up a constraint that retains compressive stresses on the surface balanced by tensile residual stresses in the interior. However, component service histories that produce subsequent plastic deformation may redistribute these residual stresses. In most engineering components, this additional plastic deformation is localized to stress concentration sites such as holes, notches, and fillets. In the case of gross plastic deformation where the entire cross section experiences material yielding the residual stress profile may redistribute, resulting in tensile stresses on the outside surface balanced by compression in the interior. This paper describes a series of experiments combined with models to explain the redistribution in residual stress depth profiles subject to applied stresses producing gross plastic strains in shot peened laboratory specimens. The initial room temperature residual stress and plastic strain profiles provide initial conditions for predictions. Model predictions correlate well with experimental results on shot peened dogbone specimens subject to single cycle and fatigue loading conditions at elevated temperature. Experiments on shot peened notched specimens do not exhibit the same stress redistribution even for larger applied stresses.

  19. 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

  20. 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

    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...

  1. Uncontrollable Stress, Coping, and Subjective Well-Being in Urban Adolescents

    Science.gov (United States)

    Coyle, Laura D.; Vera, Elizabeth M.

    2013-01-01

    The purpose of this study was to determine whether uncontrollable stress related to levels of subjective well-being (SWB) in a group of ethnically diverse urban adolescents. Additionally, the researchers examined what types of coping skills were utilized in the face of high levels of uncontrollable stress. Finally, a moderation model was proposed,…

  2. Stress and subjective well-being among first year UK undergraduate students

    OpenAIRE

    Denovan, Andrew; Macaskill, Ann

    2016-01-01

    Transition to university is stressful and successful adjustment is imperative for well-being. Historically research on transitional stress focussed on negative outcomes and ill health. This is the first UK study applying a positive psychology approach to investigate the characteristics that facilitate adjustment among new university students. A range of psychological strengths conceptualised as covitality factors, shown individually to influence the stress and subjective well-being (SWB) rela...

  3. 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.

  4. Rating of Stress Factors in Delta State Secondary Schools, Nigeria ...

    African Journals Online (AJOL)

    In terms of school-community relations, schools should identify themselves of their host communities as may be within their reach. Keywords: Human Resources Development, Rating, Stress Factors, Secondary Schools, Nigeria International Journal of Development and Management Review (INJODEMAR) Vol. 7 June ...

  5. RATING OF STRESS FACTORS IN DELTA STATE SECONDARY ...

    African Journals Online (AJOL)

    The study focused on principals and teachers' opinion on the rating of stress factors on human ... problems, teachers' interpersonal conflicts among themselves and insufficient time to perform task assigned to them. ... in the state because apart from parents, teachers are the closest to students and so, their behaviour always ...

  6. 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.

  7. [Readaptation time after photo-stress in normal subjects and glaucoma patients].

    Science.gov (United States)

    Kamppeter, B; Degenring, R F; Jonas, J B

    2003-12-01

    A photo-stress test was conducted at the subjective contrast threshold to evaluate whether psychophysical differences could be detected between chronic open-angle glaucoma patients and normal subjects. The prospective, comparative, clinical observational study included 20 patients (29 eyes) with chronic open-angle glaucoma and 20 control subjects (29 eyes). The study groups did not vary significantly in age and refractive error, but visual acuity showed a difference of 0.16. All participants underwent photo-stress using the Kontrastometer BA4. In the glaucoma group compared with the control group, the mean contrast threshold was significantly higher and the readaptation time significantly longer. The latter correlated significantly with the papillo-morphological glaucoma stage. In patients with chronic open-angle glaucoma, the foveal recovery time after a photo-stress test is significantly prolonged compared with normal subjects. It may suggest involvement of the fovea in glaucoma even if the visual acuity is 20/20.

  8. The influence of androstadienone during psychosocial stress is modulated by gender, trait anxiety and subjective stress: An fMRI study.

    Science.gov (United States)

    Chung, K C; Springer, I; Kogler, L; Turetsky, B; Freiherr, J; Derntl, B

    2016-06-01

    Androstadienone (ANDR), a bodily secreted steroid compound, is a socially relevant chemosignal that modulates subjective and (neuro)physiological responses, predominantly in females. The impact of ANDR on stress responses in males and females has not been explored. Therefore, this fMRI study aimed to examine psychosocial stress reactions induced by mental arithmetic and social evaluation on behavioral and hormonal levels (46 participants: 15 naturally cycling females in their early follicular phase (EF), 15 females on hormonal contraceptives (HC) and 16 males); and on a neural level (40 participants: 13 EF-females, 13 HC-females and 14 males) in an ANDR and placebo treatment repeated-measures design. While no gender differences emerged in subjective ratings and performance during stress, neural activation patterns differed significantly. Besides, ANDR attenuated the post-stress increase of negative mood in all participants. Region of interest analyses showed that irrespective of treatment, males showed stronger activation of the dorsolateral prefrontal cortex (DLPFC) than females. At the whole brain level, gender differences emerged indicating stronger fronto-parietal activation in males compared to HC-females on both treatments. Males showed stronger visual and fusiform activation than EF-females under ANDR. Both female groups did not show stronger activation than males. Further, error ratio in the ANDR-stress condition was positively associated with their post-stress cortisol level and increase in subjective stress in males; and male DLPFC activity in the ANDR-stress condition was negatively associated with trait anxiety. Surprisingly, compared to HC-females, EF-female only showed stronger activation of arousal-related areas under placebo treatment. Taken together, these findings suggest that the male stress reaction under social evaluative threat was stronger than female stress reactions as a function of ANDR. More specifically, this effect on behavioral and

  9. Occupational stress and self-rated health among nurses.

    Science.gov (United States)

    Theme Filha, Mariza Miranda; Costa, Maria Aparecida de Souza; Guilam, Maria Cristina Rodrigues

    2013-01-01

    To analyze the association between job stress and self-rated health among nurses in public hospital emergency units. This is a cross-sectional study undertaken through the administration of a self-administered questionnaire in a sample of 134 health professionals, using the brief version of the Job Stress Scale. Descriptive analyses of the socio-demographic, health and work variables were undertaken, as was multivariate analysis through unconditional logistic regression for adjustment of the association between job stress and poor self-rated health, in accordance with potential confounding variables, with a level of significance of 5%. 70% of the interviewees were classified as passive workers or as with high strain. Poor self-rated health was significantly greater among health professionals with high demand and low control, compared to those with low strain, after adjusting for co-variables. Low control, allied with low demand, can serve as a demotivating factor, contributing to the increase in professional dissatisfaction. It is recommended that institutions should adopt a policy of planning and managing human resources so as to encourage the participation of health professionals in decision-making, with a view to reducing job stress among nurses.

  10. Stress Detection Using Low Cost Heart Rate Sensors

    Directory of Open Access Journals (Sweden)

    Mario Salai

    2016-01-01

    Full Text Available The automated detection of stress is a central problem for ambient assisted living solutions. The paper presents the concepts and results of two studies targeted at stress detection with a low cost heart rate sensor, a chest belt. In the device validation study (n=5, we compared heart rate data and other features from the belt to those measured by a gold standard device to assess the reliability of the sensor. With simple synchronization and data cleaning algorithm, we were able to select highly (>97% correlated, low average error (2.2% data segments of considerable length from the chest data for further processing. The protocol for the clinical study (n=46 included a relax phase followed by a phase with provoked mental stress, 10 minutes each. We developed a simple method for the detection of the stress using only three time-domain features of the heart rate signal. The method produced accuracy of 74.6%, sensitivity of 75.0%, and specificity of 74.2%, which is impressive compared to the performance of two state-of-the-art methods run on the same data. Since the proposed method uses only time-domain features, it can be efficiently implemented on mobile devices.

  11. 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.

  12. Predictive behaviors for anxiety and depression in female Wistar rats subjected to cafeteria diet and stress.

    Science.gov (United States)

    da Costa Estrela, Dieferson; da Silva, Wellington Alves Mizael; Guimarães, Abraão Tiago Batista; de Oliveira Mendes, Bruna; da Silva Castro, André Luis; da Silva Torres, Iraci Lucena; Malafaia, Guilherme

    2015-11-01

    Obesity and chronic stress have been considered important public health problems that affect millions of people worldwide. Our aim was to analyze the effect of obesity associated with chronic stress on neurobehavioral parameters in female rats, considering that the association of these syndromes can enhance the negative effects on homeostasis. The animals were distributed into standard diet (Std), standard diet+stress (Std+stress), cafeteria diet (Cafe), and cafeteria diet+stress (Cafe+stress) groups. The animals of groups Std and Std+stress were fed with rodent standard feed. Groups Cafe and Cafe+stress, additionally to the standard feed, were offered palatable and calorie-rich processed food and cola-type soft drink ad libitum. From the eighth experimental week, groups Std+stress and Cafe+stress were subjected to restraint chronic stress model (50 days). After the stress protocol, predictive anxiety (open-field and elevated plus-maze tests) and depression (forced swim) were applied. The cafeteria diet was effective in inducing obesity. The ratio locomotion in the central quadrants/total locomotion evaluated during the open field test was not indicative of anxiogenic or anxiolytic effect in the animal's behavior. However, the elevated plus maze test showed that obese and stressed animals were prone to higher anxiety levels. In addition, the obese and stressed animals display less climbing behavior than all the other groups, which can be considered an indicator of depression-like behavior. Nevertheless, it is suggested that the mechanisms involved in effects of obesity associated with chronic stress be better investigated in female rats, considering the organic complexity related to these modern illnesses. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Experienced and Perceived Stress in Females With Schizophrenia and Healthy Subjects

    Directory of Open Access Journals (Sweden)

    Khodadadi Mogadam

    2016-05-01

    Full Text Available Background Schizophrenia is a psychiatric disorder characterized by chronic disturbances of thought and perception. Objectives The current study aimed to compare perceived stress in females with schizophrenia and that of healthy people. Patients and Methods The study sample included 50 patients with schizophrenia in Tuba rehabilitation center in Ardabil selected by available sampling method. Healthy group participants were selected through cloning by age, gender and marital status of the patient group. The data were collected by the questionnaire of Holmes-Rahe scale and Cohen et al. Data were analyzed by multivariate ANOVA (MANOVA using SPSS software. Results Compared with the normal subjects, patients with schizophrenia had a higher mean score in negative perceived and experienced stresses, but had a lower mean score in positive perceived stress as well as in total perceived stress. Conclusions Results showed the levels of perceived stress and negative stress play important role in the creation and maintenance of schizophrenia.

  14. The impact of subjective birth experiences on post-traumatic stress symptoms: a longitudinal study.

    Science.gov (United States)

    Garthus-Niegel, Susan; von Soest, Tilmann; Vollrath, Margarete E; Eberhard-Gran, Malin

    2013-02-01

    The aim of this prospective study was to examine the etiology of post-traumatic stress symptoms following childbirth within a transactional framework of stress. Participants were women (N = 1,499) from the Akershus Birth Cohort. These women were followed from pregnancy to 8 weeks postpartum. We modeled predisposing factors (e.g., fear of childbirth) and precipitating factors (subjective and objective birth experiences) as predictors of post-traumatic stress symptoms. Post-traumatic stress symptoms were measured by means of the Impact of Event Scale, objective birth experiences by means of birth journals, and subjective birth experiences by means of three questions. A structural equation model showed that subjective birth experiences had the highest association with post-traumatic stress symptoms. Moreover, they mediated the effect of predisposing factors and objective birth experiences. The results suggest that women's subjective birth experiences are the most important factor in the development of post-traumatic stress symptoms following childbirth.

  15. 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. 

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

    OpenAIRE

    Roselinde Kaiser Henderson; Snyder, Hannah R.; Tina eGupta; 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 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 ...

  18. Myricetin Attenuates Depressant-Like Behavior in Mice Subjected to Repeated Restraint Stress

    Directory of Open Access Journals (Sweden)

    Zegang Ma

    2015-11-01

    Full Text Available Increasing evidence has shown that oxidative stress may be implicated in chronic stress-induced depression. Several flavonoids with anti-oxidative effects have been proved to be anti-depressive. Myricetin is a well-defined flavonoid with the anti-oxidative, anti-inflammatory, anti-apoptotic, and neuroprotective properties. The aim of the present study is to investigate the possible effects of chronic administration of myricetin on depressant-like behaviors in mice subjected to repeated restraint (4 h/day for 21 days. Our results showed that myricetin administration specifically reduced the immobility time in mice exposed to chronic stress, as tested in both forced swimming test and tail suspension test. Myricetin treatment improved activities of glutathione peroxidase (GSH-PX in the hippocampus of stressed mice. In addition, myricetin treatment decreased plasma corticosterone levels of those mice subjected to repeated restraint stress. The effects of myricetin on the brain-derived neurotrophic factor (BDNF levels in hippocampus were also investigated. The results revealed that myricetin normalized the decreased BDNF levels in mice subjected to repeated restraint stress. These findings provided more evidence that chronic administration of myricetin improves helpless behaviors. The protective effects of myricetin might be partially mediated by an influence on BDNF levels and might be attributed to myricetin-mediated anti-oxidative stress in the hippocampus.

  19. Influence of deep breathing exercise on spontaneous respiratory rate and heart rate variability: a randomised controlled trial in healthy subjects.

    Science.gov (United States)

    Tharion, Elizabeth; Samuel, Prasanna; Rajalakshmi, R; Gnanasenthil, G; Subramanian, Rajam Krishna

    2012-01-01

    Studies show that yogic type of breathing exercises reduces the spontaneous respiratory rate. However, there are no conclusive studies on the effects of breathing exercise on heart rate variability. We investigated the effects of non-yogic breathing exercise on respiratory rate and heart rate variability. Healthy subjects (21-33 years, both genders) were randomized into the intervention group (n=18), which performed daily deep breathing exercise at 6 breaths/min (0.1 Hz) for one month, and a control group (n=18) which did not perform any breathing exercise. Baseline respiratory rate and short-term heart rate variability indices were assessed in both groups. Reassessment was done after one month and the change in the parameters from baseline was computed for each group. Comparison of the absolute changes [median (inter-quartile ranges)] of the parameters between the intervention and control group showed a significant difference in the spontaneous respiratory rate [intervention group -2.50 (-4.00, -1.00), control group 0.00 (-1.00, 1.00), cycles/min, Prate and cardiac autonomic modulation of the intervention group were significant, when compared to the changes in the control group. Thus practice of deep slow breathing exercise improves heart rate variability in healthy subjects, without altering their cardiac autonomic balance. These findings have implications in the use of deep breathing exercises to improve cardiac autonomic control in subjects known to have reduced heart rate variability.

  20. [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.

  1. 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

  2. Characteristics of heart rate variability in alcohol-dependent subjects and nondependent chronic alcohol users.

    Science.gov (United States)

    Karpyak, Victor M; Romanowicz, Magdalena; Schmidt, John E; Lewis, Kriste A; Bostwick, John M

    2014-01-01

    Heart rate variability (HRV) is an objective and sensitive measure of integrated physiological functioning reflective of heart rhythm responsivity to internal and external demands. Reduced HRV is associated with vulnerability to stress and deterioration of medical and/or psychiatric conditions, while increased HRV is associated with a favorable treatment response and recovery from various medical and/or psychiatric conditions. Our previous review found that acute alcohol consumption caused decreased parasympathetic and increased sympathetic HRV effects in both nonalcoholic and chronic alcohol users. This review investigates the effects of chronic alcohol consumption on HRV in alcohol-dependent subjects and nondependent users. MEDLINE, Scopus, and PubMed were searched for human experimental and clinical trials that measured the effects of chronic alcohol use on HRV. Only publications that included a description of their study designs and clearly stated methodologies for data collections, and outcome measures were reviewed. We have reviewed a total of 24 articles. In nondependent users, low dose (approximating the recommended daily amount of 1 standard drink in women and 2 in men) use is associated with increased HRV parameters compared to those who drink less frequently or abstain altogether. A further increase in consumption is associated with decreased HRV compared to both abstainers and more moderate drinkers. HRV changes during withdrawal generally follow the same negative direction but are more complex and less understood. In dependent subjects, an improvement in HRV was seen following abstinence but remained reduced compared to nonalcoholic controls. This review demonstrates that HRV changes associated with chronic use follow a J-shaped curve. It supports recommendations that limit daily alcohol intake to no more than 2 drinks for men and 1 drink for women. Future studies should investigate HRV as a biomarker of alcoholism development and treatment response as

  3. Stress state and strain rate dependence of the human placenta.

    Science.gov (United States)

    Weed, Benjamin C; Borazjani, Ali; Patnaik, Sourav S; Prabhu, R; Horstemeyer, M F; Ryan, Peter L; Franz, Thomas; Williams, Lakiesha N; Liao, Jun

    2012-10-01

    Maternal trauma (MT) in automotive collisions is a source of injury, morbidity, and mortality for both mothers and fetuses. The primary associated pathology is placental abruption in which the placenta detaches from the uterus leading to hemorrhaging and termination of pregnancy. In this study, we focused on the differences in placental tissue response to different stress states (tension, compression, and shear) and different strain rates. Human placentas were obtained (n = 11) for mechanical testing and microstructure analysis. Specimens (n = 4+) were tested in compression, tension, and shear, each at three strain rates (nine testing protocols). Microstructure analysis included scanning electron microscopy, histology, and interrupted mechanical tests to observe tissue response to various loading states. Our data showed the greatest stiffness in tension, followed by compression, and then by shear. The study concludes that mechanical behavior of human placenta tissue (i) has a strong stress state dependence and (ii) behaves in a rate dependent manner in all three stress states, which had previously only been shown in tension. Interrupted mechanical tests revealed differences in the morphological microstructure evolution that was driven by the kinematic constraints from the different loading states. Furthermore, these structure-property data can be used to develop high fidelity constitutive models for MT simulations.

  4. 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.

  5. Baroreceptor unloading does not limit forearm sweat rate during severe passive heat stress.

    Science.gov (United States)

    Schlader, Zachary J; Gagnon, Daniel; Lucas, Rebekah A I; Pearson, James; Crandall, Craig G

    2015-02-15

    This study tested the hypothesis that sweat rate during passive heat stress is limited by baroreceptor unloading associated with heat stress. Two protocols were performed in which healthy subjects underwent passive heat stress that elicited an increase in intestinal temperature of ∼1.8°C. Upon attaining this level of hyperthermia, in protocol 1 (n = 10, 3 females) a bolus (19 ml/kg) of warm (∼38°C) isotonic saline was rapidly (5-10 min) infused intravenously to elevate central venous pressure (CVP), while in protocol 2 (n = 11, 5 females) phenylephrine was infused intravenously (60-120 μg/min) to return mean arterial pressure (MAP) to normothermic levels. In protocol 1, heat stress reduced CVP from 3.9 ± 1.9 mmHg (normothermia) to -0.6 ± 1.4 mmHg (P 0.999). Sweat rate was elevated by heat stress (1.21 ± 0.44 mg·cm(-2)·min(-1)) but remained unchanged during rapid saline infusion (1.26 ± 0.47 mg·cm(-2)·min(-1), P = 0.5), whereas cutaneous vascular conductance increased from 77 ± 10 to 101 ± 20% of local heating max (P = 0.029). In protocol 2, MAP was reduced with heat stress from 85 ± 7 mmHg to 76 ± 8 mmHg (P = 0.048). Although phenylephrine infusion returned MAP to normothermic levels (88 ± 7 mmHg; P > 0.999), sweat rate remained unchanged during phenylephrine infusion (1.39 ± 0.22 vs. 1.41 ± 0.24 mg·cm(-2)·min(-1); P > 0.999). These data indicate that both cardiopulmonary and arterial baroreceptor unloading do not limit increases in sweat rate during passive heat stress. Copyright © 2015 the American Physiological Society.

  6. 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

  7. 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.

  8. Subjective Well-Being in Urban, Ethnically Diverse Adolescents the Role of Stress and Coping

    Science.gov (United States)

    Vera, Elizabeth M.; Vacek, Kimberly; Blackmon, Sha'kema; Coyle, Laura; Gomez, Kenia; Jorgenson, Katherine; Luginbuhl, Paula; Moallem, Isabel; Steele, John C.

    2012-01-01

    This study examines stressors, general stress levels, coping strategies, and subjective well-being in a sample of 144 ethnically diverse, urban adolescents (mean age of 13). The most frequently reported stressors include the death of a family member, feeling socially isolated, family financial problems, injury of a family member, and parents…

  9. 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

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

    Directory of Open Access Journals (Sweden)

    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.

  11. 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'sbelief that they are less likely to cause cancer (p=0.046). Neither false beliefs nor subjective ratings directly affected smoking behaviors. Significant interactions of strength and taste ratings with beliefs (p'sbeliefs 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.

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

    Science.gov (United States)

    Bhansali, Shipra; Bhansali, Anil; Walia, Rama; Saikia, Uma Nahar; Dhawan, Veena

    2017-01-01

    Hyperglycemia-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. A 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. With 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. Increasing 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.

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

    Directory of Open Access Journals (Sweden)

    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. Predicting self-rated mental and physical health: the contributions of subjective socioeconomic status and personal relative deprivation.

    Science.gov (United States)

    Callan, Mitchell J; Kim, Hyunji; Matthews, William J

    2015-01-01

    Lower subjective socioeconomic status (SSS) and higher personal relative deprivation (PRD) relate to poorer health. Both constructs concern people's perceived relative social position, but they differ in their emphasis on the reference groups people use to determine their comparative disadvantage (national population vs. similar others) and the importance of resentment that may arise from such adverse comparisons. We investigated the relative utility of SSS and PRD as predictors of self-rated physical and mental health (e.g., self-rated health, stress, health complaints). Across six studies, self-rated physical and mental health were on the whole better predicted by measures of PRD than by SSS while controlling for objective socioeconomic status (SES), with SSS rarely contributing unique variance over and above PRD and SES. Studies 4-6 discount the possibility that the superiority of PRD over SSS in predicting health is due to psychometric differences (e.g., reliability) or response biases between the measures.

  15. Within-Subject Reliability and between-Subject Variability of Oxidative Stress Markers in Saliva of Healthy Subjects: A Longitudinal Pilot Study

    Directory of Open Access Journals (Sweden)

    Iva Z. Alajbeg

    2017-01-01

    Full Text Available The present study evaluated diurnal variations and day-to-day fluctuations of salivary oxidative stress (OS markers in healthy adult individuals. Whole unstimulated saliva was collected at 2 time intervals over 3 consecutive days. Glutathione peroxidase (GPX, superoxide dismutase (SOD, total antioxidant capacity (TAC, and uric acid (UA were analyzed using spectrophotometric methods, while 8-hydroxydeoxyguanosine (8-OHdG and malondialdehyde (MDA were determined using immunoassays. No significant differences for salivary OS markers between men and women were observed. For all examined OS markers, no significant day-to-day variations were demonstrated. Significant diurnal variations were found in salivary GPX, TAC and MDA levels. For SOD, TAC, GPX, and UA, good-to-moderate intraindividual coefficients of variations (CVs were observed in more than 75% of the subjects. For MDA and 8-OHdG, intraindividual CVs > 35% were observed in 60% and 40% of the subjects, respectively. Between-subject variance was wide for all examined OS markers (CV% 30.08%–85.70%. Due to high intraindividual variability in the salivary concentrations of MDA and 8-OHdG, those markers cannot be reliably verified based on single measurements and multiple measurements over several days would provide more reliable information. Salivary SOD, TAC, GPX, and UA proved stable across three days of measurement. Trial Registration. ClinicalTrials.gov NCT03029494. Registered on 2017-01-19.

  16. 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.

  17. Comparison of the subjective sense of high or low metabolism and objectively measured resting metabolic rate.

    Science.gov (United States)

    Wallhuss, Andreas; Isik, Markus; Nystrom, Fredrik H

    2010-09-01

    To measure caloric intake, physical activity level and resting metabolic rate in participants having the subjective opinion of either having a high or low metabolic rate. Recruitment by local advertising of healthy subjects feeling that they have high or low metabolism, i.e. either a tendency to easily stay lean ('high') or to very easily gain weight ('low') also when taking food intake in comparison with physical activity into account. Walking distance was estimated by pedometry, assessment of caloric intake was determined by food registration. Measurement of resting metabolic rate was performed in the fasting state. We recruited 44 participants with a sense of 'high' metabolism and 12 subjects in the contrasting group. Subjects with 'high' metabolism were leaner ('high': 20.4 +/- 2.1 kg/m(2), 'low': 27.8 +/- 7.5 kg/m(2), p difference in the measured resting metabolic rate between the two groups ('high': 7230 +/- 1233 kJ/24 h, 'low': 7430 +/- 1422 kJ/24 h, p = 0.6), nor was there any difference in physical activity measured by pedometry. Resting metabolic rate was negatively correlated with age and positively correlated with BMI in multivariate analyses of the total cohort. The sense of having a low or high metabolic rate is not related to actual resting metabolic rate.

  18. Effect of mild mental stress on solid phase gastric emptying in healthy subjects.

    Science.gov (United States)

    Roland, J; Dobbeleir, A; Vandevivere, J; Ham, H R

    1990-04-01

    Radionuclide gastric emptying studies are performed in clinical routine but the possible influence of the mental state of the patient is never taken into account. We wanted to evaluate the effect of a mild psychological stress on solid phase gastric emptying in healthy young male volunteers. The standard meal consisted of a pancake (500 kJ) without additional liquid. Simultaneous dynamic acquisitions of gastric activity in anterior and posterior projection were taken during 90 min starting from the onset of the meal. Gastric emptying was evaluated three times in basal conditions and once under mental stress. Stress was induced by means of a dichotomous listening test, lasting for 30 min, starting at the end of the meal. The results of rest and stress studies were compared. Mild mental stress has a significant influence on gastric emptying. The lag phase increased from 11 +/- 3 min to 36 +/- 10 min (mean +/- S.D.) (p less than 0.005) and the gastric emptying rate from 79 +/- 13%/hour to 100 +/- 31%/hour (mean +/- S.D.) (not significant). During a stress period gastric emptying as a whole is delayed but this is mainly due to the prolongation of the lag phase. Our data also suggest that during the stress period gastric emptying is interrupted and reactivated once the stress period has ended.

  19. Physiological quality of sesame seeds produced from plants subjected to water stress

    Directory of Open Access Journals (Sweden)

    Ronimeire Torres da Silva

    2016-12-01

    Full Text Available ABSTRACT Germination and seed vigor may be influenced by several factors, such as water stress during production, which affect crops differently according to the phenological stage of the plant. The aim of this study therefore was to evaluate the physiological quality of sesame seeds from plants subjected to water stress at different phenological stages. To this end, sesame plants were subjected to water stress at the following stages: I - germination to the start of vegetative growth (T1; II - vegetative growth to flowering (T2; III - flowering to pod formation (T3; IV - fruit maturation (T4; also for stress at all stages (T5 and full irrigation (T6. By weighing and daily irrigation of the containers, levels were kept at 50% of pot capacity (CV for treatments with water deficit, and at 100% CV for treatments with no deficit. At 90 days after planting, the plants were harvested. The seeds were evaluated by germination test, first germination count, germination speed index, mean germination time, accelerated aging, electrical conductivity, seedling emergence, emergence speed index, mean time of emergence, seedling length and seedling dry weight. Sesame seeds from plants grown under water deficit display lower physiological quality. Between germination and the start of vegetative growth, and between flowering and fruit formation, the sesame is more sensitive to water stress, so that water limitation during these periods results in the production of seeds of low physiological quality.

  20. 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.

  1. Performance of Pre-Stressed Sandwich Composites Subjected to Shock Wave Loading

    Directory of Open Access Journals (Sweden)

    Shukla A.

    2010-06-01

    Full Text Available The present paper experimentally studies the dynamic behaviour of prestressed sandwich composites under blast loading. The in-plane static compression loadings are implemented on the sandwich composites before they are subjected to the transverse shock wave loading. Three different pre-stress levels are chosen. 3-D realtime deformation data are captured by two high-speed photography systems: a backview Digital Image Correlation (DIC system and a side-view camera system. The results show that pre-stresses can induce local buckling in the front face-sheet of sandwich composites, consequently reduce the blast resistance of sandwich composites.

  2. Effect of Magnolia officinalis and Phellodendron amurense (Relora?) on cortisol and psychological mood state in moderately stressed subjects

    OpenAIRE

    Talbott, Shawn M; Talbott, Julie A; Pugh, Mike

    2013-01-01

    Background Magnolia (Magnolia officinalis) and Phellodendron (Phellodendron amurense) barks are medicinal plants commonly used as traditional remedies for reducing stress and anxiety. Modern dietary supplements are intended to induce relaxation and reduce stress as well as stress-related eating. Previous studies have shown the combination of Magnolia/Phellodendron (MP) to reduce both cortisol exposure and the perception of stress/anxiety, while improving weight loss in subjects with stress-re...

  3. Influence of academic examination stress on hematological measurements in subjectively healthy volunteers.

    Science.gov (United States)

    Maes, M; Van Der Planken, M; Van Gastel, A; Bruyland, K; Van Hunsel, F; Neels, H; Hendriks, D; Wauters, A; Demedts, P; Janca, A; Scharpé, S

    1998-09-21

    Some recent reports showed that a brief exposure to a mental stressor during 3-20 min may induce hematological changes in humans. The aim of the present study was to examine the effects of academic examination stress on erythron variables, such as the number of red blood cells (RBC), hemoglobin (Hb), hematocrit (Ht), mean corpuscular volume (MCV), mean cell Hb (MCH), mean cell Hb concentration (MCHC), RBC distribution width (RDW), and serum iron and transferrin (Tf). The above variables were determined in 41 students in three conditions, i.e. the stress condition (the day before a difficult oral exam) and two baseline conditions, i.e. a few weeks earlier and later. At the same occasions, subjects completed the Perceived Stress Scale (PSS), the state version of the State-Trait Anxiety Inventory (STAI) and the Profile of Mood States (POMS). Academic examination stress significantly increased Ht, Hb, MCV, MCH and MCHC and significantly decreased RDW. There were significant relationships between the stress-induced changes in the PSS, STAI and POMS scores and those in Ht, Hb, MCV and MCH (allpositive) and RDW (negative). It is concluded that academic examination stress induces significant hematological changes indicative of an increased number of large RBC and increased hemoglobinisation, which cannot be explained by shifts of fluid out of the intravascular space, concentrating non-diffusible blood constituents.

  4. 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.

  5. Low-Grade Inflammation and Ambulatory Cortisol in Adolescents: Interaction Between Interviewer-Rated Versus Self-Rated Acute Stress and Chronic Stress.

    Science.gov (United States)

    Schreier, Hannah M C; Chen, Edith

    To determine whether the association between self-rated or interviewer-rated recent acute stress exposures and low-grade inflammation and daily cortisol production in adolescents is moderated by chronic stress ratings. Acute and chronic stress exposures were assessed in 261 adolescents aged 13 to 16 years using a semistructured life stress interview. The negative impact of acute stressors was independently rated by both adolescents (self-rated) and interviewers (interviewer-rated). Markers of inflammation (interleukin (IL)-6, IL-1ra, C-reactive protein) were measured from peripheral blood samples obtained via antecubital venipuncture. Participants collected 4 saliva samples at home on each of 6 consecutive days for the analysis of diurnal salivary cortisol profiles. There were no main effects of acute stressors (self- and interviewer-rated) and chronic family or peer stress on adolescent inflammation markers and cortisol (p values > .10). However, the interaction between interviewer-rated acute stress and chronic family stress was significantly associated with adolescent inflammation markers (IL-6, IL-1ra). Specifically, as chronic family stress increased, the association between acute stressor impact (interviewer-rated) and inflammation markers became more positive (IL-6 (B = .054, SE = .023, p = .022); IL-1ra (B = .030, SE = .014, p = .034)). Interactions between self-rated acute stress and chronic family stress were not associated with any biological measures (p values > .10). Interactions between acute stressor impact (both self- and interviewer-rated) and chronic peer stress were also not significantly associated with any biological measures (p values > .05). Among adolescents, interviewer-based ratings of acute stressor impact may allow for better prediction of health-relevant inflammation markers than adolescents' own ratings.

  6. 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

    Intake of fish oil reduces the risk of CHD and CHD deaths. Marine n-3 fatty acids (FA) are susceptible to oxidation, but to our knowledge, the health effects of intake of oxidised fish oil have not previously been investigated in human subjects. The aim of the present study was to investigate...... 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...

  7. 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...

  8. Condylar and disk position and signs and symptoms of temporomandibular disorders in stress-free subjects.

    Science.gov (United States)

    Vasconcelos Filho, José Osmar; Menezes, Alynne Vieira de; Freitas, Deborah Queiroz de; Manzi, Flávio Ricardo; Bóscolo, Frab Norberto; de Almeida, Solange Maria

    2007-09-01

    The authors conducted a study in subjects who tested free of psychological stress to determine the position of the condyle and whether that position was related to signs and symptoms of temporomandibular disorders (TMDs). Forty subjects underwent psychological evaluation to ensure freedom from psychological stress. The authors evaluated tenderness of the masticatory muscles and temporomandibular joints (TMJs) by means of bimanual digital palpation, and they determined the positions of the condyle and disk by using magnetic resonance imaging. A total of 23.75 percent of the condyles were displaced away from the centric position either anteriorly (3.75 percent) or posteriorly (20.00 percent). chi(2) analysis showed a relationship between the position of the condyle and displacement of the disk, as well as a relationship between the position of the condyle and tenderness of the TMJs. Although these relationships proved significant, it cannot be assumed that displacement of the condyle away from the centric position is predictive of TMD. Only two subjects were judged to have had TMJ internal derangement. Thus, the absence of psychological stress seems to have played a role in this finding.

  9. 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 * behavior al indices Subject RIV: AN - Psychology Impact factor: 2.081, year: 2008

  10. 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

    Subcutaneous adipose tissue blood flow rate was measured in the lower leg of 22 normal human subjects over 12- to 20-h ambulatory conditions. The 133Xe washout technique, portable CdTe(Cl) detectors, and a portable data storage unit were used. The tracer depot was applied on the medial aspect...

  11. 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 ...

  12. 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

  13. Seasonal differences in melatonin concentrations and heart rates during sleep in obese subjects in Japan

    Science.gov (United States)

    Sato, Maki; Kanikowska, Dominika; Iwase, Satoshi; Shimizu, Yuuki; Nishimura, Naoki; Inukai, Yoko; Sato, Motohiko; Sugenoya, Junichi

    2013-09-01

    During the past several decades, obesity has been increasing globally. In Japan, obesity is defined by a BMI of 25 kg/m2 or over; 28.6 % of men and 20.6 % of women are obese. Obese people have an increased incidence of developing cardiovascular, renal, and hormonal diseases and sleep disorders. Obese people also have shortened sleep durations. We investigated seasonal differences in melatonin concentrations, heart rates, and heart rate variability during sleep in obese subjects in Japan. Five obese (BMI, 32.0 ± 4.9 kg/m2) and five non-obese (BMI, 23.2 ± 2.9 kg/m2) men participated in this study in the summer and winter. Electrocardiograms were measured continuously overnight in a climatic chamber at 26 °C with a relative humidity of 50 %. Saliva samples for melatonin were collected at 2300 hours, 0200 hours, and 0600 hours. We found that melatonin concentrations during sleep in obese subjects were significantly lower than those in non-obese subjects in the winter. Heart rate during sleep in winter was significantly higher than that in summer in both obese and non-obese subjects. Heart rate variability was not significantly different in the summer and winter in both obese and non-obese subjects. Our results show that decreased nocturnal melatonin concentrations during winter in obese men may be related to higher heart rates, and this may suggest that obese men are at an increased risk of a cardiovascular incident during sleep, especially in the winter.

  14. Estimation of Subjective Difficulty and Psychological Stress by Ambient Sensing of Desk Panel Vibrations

    Science.gov (United States)

    Hamaguchi, Nana; Yamamoto, Keiko; Iwai, Daisuke; Sato, Kosuke

    We investigate ambient sensing techniques that recognize writer's psychological states by measuring vibrations of handwriting on a desk panel using a piezoelectric contact sensor attached to its underside. In particular, we describe a technique for estimating the subjective difficulty of a question for a student as the ratio of the time duration of thinking to the total amount of time spent on the question. Through experiments, we confirm that our technique correctly recognizes whether or not a person writes something down on paper by measured vibration data at the accuracy of over 80 %, and that the order of computed subjective difficulties of three questions is coincident with that reported by the subject in 60 % of experiments. We also propose a technique to estimate a writer's psychological stress by using the standard deviation of the spectrum of the measured vibration. Results of a proof-of-concept experiment show that the proposed technique correctly estimates whether or not the subject feels stress at least 90 % of the time.

  15. 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.

  16. 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...

  17. 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... Appendix B to Part 541—Light Duty Truck Lines With Theft Rates Below the 1990/91 Median Theft Rate, Subject...

  18. 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

  19. Relationship between heart rate variability and endothelial function in healthy subjects.

    Science.gov (United States)

    Pinter, Alexandra; Horvath, Tamas; Sarkozi, Adrienn; Kollai, Mark

    2012-08-16

    In various diseased states reduced cardiac vagal activity is accompanied by impaired endothelial function. Evidence from animal studies indicates interaction between the two systems, but such data from human studies is limited. The aim of this study was to test the hypothesis that cardiac vagal activity and endothelial function are related in healthy individuals. 46 young males were studied. From 10 minute long ECG recordings mean RR-interval and time and frequency domain vagal heart rate variability indices (RMSSD; pNN50 and HF, respectively) were determined. Heart rate variability indices were used to define cardiac vagal activity. Endothelial function was assessed by measuring brachial artery flow mediated dilation. Hyperemic, diastolic shear rate was used to normalize flow mediated dilation. All three vagal heart rate variability indices correlated significantly and positively with flow mediated dilation across subjects, with r values within the range of 0.43-0.52, pheart rate variability indices remained significantly associated with normalized flow mediated dilation. RR-interval was related to most heart rate variability indices, but was not related to flow mediated dilation. Our data demonstrate that vagal heart rate variability indices are related to flow mediated dilation across healthy male subjects. The results cannot serve as evidence of a causal relationship, but are of interest and render for further investigation into underlying mechanisms. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. [Influence of affectivity trait on relationships between occupational stress and subjective physical health and job satisfaction].

    Science.gov (United States)

    Yu, Shan-fa; Zhou, Wen-hui; Gu, Gui-zhen

    2008-09-01

    To explore the influence of affectivity trait on relationships between occupational stress and subjective physical health and job satisfaction. Self-reports for psychosocial work conditions and health and well-being in a sample of 878 workers from a thermal power plant in China were conducted using the job demand-control model, the effort-reward imbalance model, job satisfaction, depression symptom, and physical health complaints questionnaires. Logistic regression analysis was used by controlling for age, sex, and educational level. Negative and positive affectivity were correlated with occupational stressors or strains (Paffectivity or positive affectivity was controlled; Odds ratios decreased greater when negative affectivity and positive affectivity were controlled simultaneously. Furthermore in some equation no variable entered. Affectivity trait has effect on relationships between occupational stress and subjective physical health and job satisfaction. According to the outcome category of study, the possible confounding role of affectivity should be controlled in the study of the relationships between occupational stress and health self-reports.

  6. Effects of acute physical exercise on oxidative stress and inflammatory status in young, sedentary obese subjects.

    Science.gov (United States)

    Accattato, Francesca; Greco, Marta; Pullano, Salvatore A; Carè, Ilaria; Fiorillo, Antonino S; Pujia, Arturo; Montalcini, Tiziana; Foti, Daniela P; Brunetti, Antonio; Gulletta, Elio

    2017-01-01

    Circulating oxidative stress and pro-inflammatory markers change after regular physical exercise; however, how a short session of acute physical activity affects the inflammatory status and redox balance in sedentary individuals is still unclear. Aim of this study is to assess antioxidant and inflammatory parameters, both at rest and after acute exercise, in sedentary young men with or without obesity. Thirty sedentary male volunteers, aged 20-45 (mean age 32 ± 7 years), were recruited, divided into 3 groups (normal weight: BMI group comparisons demonstrated significantly higher Glutathione Reductase activity in severely obese subjects in the post-exercise period (P = 0.036), and higher EGF levels in normal weight individuals, either before (P = 0.003) and after exercise (P = 0.05). Intra-group comparisons showed that the acute exercise stress induced a significant increase in Glutathione Reductase activity in severely obese subjects only (P = 0.007), a significant decrease in MCP-1 in the normal weight group (P = 0.02), and a decrease in EGF levels in all groups (normal weight: P = 0.025, overweight/moderate obesity: P = 0.04, severe obesity: P = 0.018). Altogether, these findings suggest that in sedentary individuals with different ranges of BMI, Glutathione Reductase and distinct cytokines are differentially involved into the adaptive metabolic changes and redox responses induced by physical exercise. Therefore, these biomarkers may have the potential to identify individuals at higher risk for developing diseases pathophysiologically linked to oxidative stress.

  7. 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.

  8. Creep Strain and Strain Rate Response of 2219 Al Alloy at High Stress Levels

    Science.gov (United States)

    Taminger, Karen M. B.; Wagner, John A.; Lisagor, W. Barry

    1998-01-01

    As a result of high localized plastic deformation experienced during proof testing in an International Space Station connecting module, a study was undertaken to determine the deformation response of a 2219-T851 roll forging. After prestraining 2219-T851 Al specimens to simulate strains observed during the proof testing, creep tests were conducted in the temperature range from ambient temperature to 107 C (225 F) at stress levels approaching the ultimate tensile strength of 2219-T851 Al. Strain-time histories and strain rate responses were examined. The strain rate response was extremely high initially, but decayed rapidly, spanning as much as five orders of magnitude during primary creep. Select specimens were subjected to incremental step loading and exhibited initial creep rates of similar magnitude for each load step. Although the creep rates decreased quickly at all loads, the creep rates dropped faster and reached lower strain rate levels for lower applied loads. The initial creep rate and creep rate decay associated with primary creep were similar for specimens with and without prestrain; however, prestraining (strain hardening) the specimens, as in the aforementioned proof test, resulted in significantly longer creep life.

  9. Achilles tendon stress is more sensitive to subject-specific geometry than subject-specific material properties: A finite element analysis.

    Science.gov (United States)

    Hansen, Wencke; Shim, Vickie B; Obst, Steven; Lloyd, David G; Newsham-West, Richard; Barrett, Rod S

    2017-05-03

    This study used subject-specific measures of three-dimensional (3D) free Achilles tendon geometry in conjunction with a finite element method to investigate the effect of variation in subject-specific geometry and subject-specific material properties on tendon stress during submaximal isometric loading. Achilles tendons of eight participants (Aged 25-35years) were scanned with freehand 3D ultrasound at rest and during a 70% maximum voluntary isometric contraction. Ultrasound images were segmented, volume rendered and transformed into subject-specific 3D finite element meshes. The mean (±SD) lengths, volumes and cross-sectional areas of the tendons at rest were 62±13mm, 3617±984mm3 and 58±11mm2 respectively. The measured tendon strain at 70% MVIC was 5.9±1.3%. Subject-specific material properties were obtained using an optimisation approach that minimised the difference between measured and modelled longitudinal free tendon strain. Generic geometry was represented by the average mesh and generic material properties were taken from the literature. Local stresses were subsequently computed for combinations of subject-specific and generic geometry and material properties. For a given geometry, changing from generic to subject-specific material properties had little effect on the stress distribution in the tendon. In contrast, changing from generic to subject-specific geometry had a 26-fold greater effect on tendon stress distribution. Overall, these findings indicate that the stress distribution experienced by the living free Achilles tendon of a young and healthy population during voluntary loading are more sensitive to variation in tendon geometry than variation in tendon material properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. 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.

  11. Microscale consolidation analysis of relaxation behavior of single living chondrocytes subjected to varying strain-rates.

    Science.gov (United States)

    Nguyen, Trung Dung; Oloyede, Adekunle; Singh, Sanjleena; Gu, YuanTong

    2015-09-01

    Besides the elastic stiffness, the relaxation behavior of single living cells is also of interest of various researchers when studying cell mechanics. It is hypothesized that the relaxation response of the cells is governed by both intrinsic viscoelasticity of the solid phase and fluid-solid interactions mechanisms. There are a number of mechanical models have been developed to investigate the relaxation behavior of single cells. However, there is lack of model enable to accurately capture both of the mechanisms. Therefore, in this study, the porohyperelastic (PHE) model, which is an extension of the consolidation theory, combined with inverse Finite Element Analysis (FEA) technique was used at the first time to investigate the relaxation response of living chondrocytes. This model was also utilized to study the dependence of relaxation behavior of the cells on strain-rates. The stress-relaxation experiments under the various strain-rates were conducted with the Atomic Force Microscopy (AFM). The results have demonstrated that the PHE model could effectively capture the stress-relaxation behavior of the living chondrocytes, especially at intermediate to high strain-rates. Although this model gave some errors at lower strain-rates, its performance was acceptable. Therefore, the PHE model is properly a promising model for single cell mechanics studies. Moreover, it has been found that the hydraulic permeability of living chondrocytes reduced with decreasing of strain-rates. It might be due to the intracellular fluid volume fraction and the fluid pore pressure gradients of chondrocytes were higher when higher strain-rates applied. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. [Risk stratification of asymptomatic subjects using resting ECG and stress ECG].

    Science.gov (United States)

    Möhlenkamp, Stefan; Wieneke, Heinrich; Sack, Stefan; Erbel, Raimund

    2007-08-01

    The resting electrocardiogram (ECG) and stress ECG are established tests in the array of cardiovascular diagnostic modalities. In addition to their diagnostic value for structural heart disease and rhythm disorders, ECGs at rest or during stress also contain prognostically relevant information. Several ECG abnormalities, e.g., left ventricular hypertrophy (LVH), Q waves, ST segment changes, left bundle branch block, atrial fibrillation or QT interval prolongation, were shown to be associated with cardiovascular events. Differences in study design, the cohorts of investigation and morphological definitions of ECG abnormalities may in part be responsible for the abnormalities not being implemented in risk stratification algorithms. The non-ST-segment-related variables in stress testing, e.g., functional capacity, chronotropic (in)competence, heart rate (HR) recovery, and the HR/ST index and slope, could be identified as prognostically relevant markers in population-based studies. For many of these resting and stress ECG-based abnormalities, associations with the extent of subclinical atherosclerosis in persons without established coronary heart disease were observed, indicating a preclinical relationship between epicardial atherosclerosis and myocardial pathology. The resting and the stress ECG provide a number of prognostically relevant indices that can easily be obtained in routine clinical practice, but have thus far found little acceptance for risk stratification of asymptomatic individuals.

  13. Caffeine Enhances Heart Rate Variability in Middle-Aged Healthy, But Not Heart Failure Subjects.

    Science.gov (United States)

    Notarius, Catherine F; Floras, John S

    2012-06-01

    In chronic heart failure (CHF) due to left ventricular dysfunction, diminished heart rate variability (HRV) is an independent predictor of poor prognosis. Caffeine has been shown to increase HRV in young healthy subjects. Such an increase may be of potential benefit to patients with CHF. We hypothesized that intravenous infusion of caffeine would increase HRV in CHF, and in age-matched healthy control subjects. On two separate days, 11 patients (1F) with CHF (age=51.3±4.6 years; left ventricular ejection fraction=18.6±2.7%; mean±standard error) and 10 healthy control subjects (age=48.0±4.0) according to a double-blind randomization design, received either saline or caffeine (4 mg/kg) infusion. We assessed HRV over 7 minutes of supine rest (fast Fourier Transform analysis) to determine total spectral power as well as its high-frequency (HF) (0.15-0.50 Hz) and low-frequency (LF) (0.05-0.15 Hz) components, and recorded muscle sympathetic nerve activity (MSNA) directly from the peroneal nerve (microneurography). In healthy control subjects, compared with saline, caffeine reduced both heart rate and sympathetic nerve traffic (p≤0.003) and increased the ratio of HF/total power (p≤0.05). Baseline LF power and the ratio LF/HF were significantly lower in CHF compared with controls (p=0.02), but caffeine had no effect on any element of HRV. Caffeine increases cardiac vagal heart rate modulation and reduces MSNA in middle-aged healthy subjects, but not in those with CHF.

  14. 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...

  15. Persistent effects of cognitive-behavioral stress management on cortisol responses to acute stress in healthy subjects--a randomized controlled trial.

    Science.gov (United States)

    Hammerfald, K; Eberle, C; Grau, M; Kinsperger, A; Zimmermann, A; Ehlert, U; Gaab, J

    2006-04-01

    Psychosocial stress leads to a release of cortisol. While this psychoneuroendocrine response helps to maintain physiological as well as psychological equilibrium under stress, exaggerated secretion of cortisol has been shown to have negative effects on somatic health and cognitive functioning. The study set out to examine the long-term effects of cognitive-behavioral stress management training on cortisol stress responses in healthy men and women. Eighty-three healthy subjects were randomly assigned to cognitive-behavioral stress management (CBSM) training or a control condition. Four months after the CBSM, 76 subjects underwent a standardized psychosocial stress test. Salivary cortisol responses were assessed repeatedly before and after the stress test. Subjects in the CBSM group showed significantly reduced cortisol stress responses. With regard to gender, this effect was observed in both men and women. However, the magnitude of the CBSM effect on cortisol responses was smaller in women than in men. Use of oral contraceptives in women influenced the cortisol response, but did not have an impact on the CBSM effect on cortisol. The results show that the previously reported attenuation of cortisol stress responses through CBSM persists and are observable in both men and women. Since stress-induced alterations of hypothalamus pituitary adrenal axis functioning are discussed to be involved in the onset and maintenance of both somatic and psychiatric conditions, similar interventions could be used for prevention and therapy of these detrimental stress effects.

  16. 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.

  17. Disentangling preference ratings of concert hall acoustics using subjective sensory profiles.

    Science.gov (United States)

    Lokki, Tapio; Pätynen, Jukka; Kuusinen, Antti; Tervo, Sakari

    2012-11-01

    Subjective evaluation of acoustics was studied by recording nine concert halls with a simulated symphony orchestra on a seat 12 m from the orchestra. The recorded music was spatially reproduced for subjective listening tests and individual vocabulary profiling. In addition, the preferences of the assessors and objective parameters were gathered. The results show that concert halls were discriminated using perceptual characteristics, such as Envelopment/Loudness, Reverberance, Bassiness, Proximity, Definition, and Clarity. With these perceptual dimensions the preference ratings can be explained. Seventeen assessors were divided into two groups based on their preferences. The first group preferred concert halls with relatively intimate sound, in which it is quite easy to hear individual instruments and melody lines. In contrast, the second group preferred a louder and more reverberant sound with good envelopment and strong bass. Even though all halls were recorded exactly at the same distance, the preference is best explained with subjective Proximity and with Bassiness, Envelopment, and Loudness to some extent. Neither the preferences nor the subjective ratings could be fully explained by objective parameters (ISO3382-1:2009), although some correlations were found.

  18. 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.

  19. Classification of heart rate signals of healthy and pathological subjects using threshold based symbolic entropy.

    Science.gov (United States)

    Aziz, Wajid; Rafique, M; Ahmad, I; Arif, M; Habib, Nazneen; Nadeem, M S A

    2014-09-01

    The dynamical fluctuations of biological signals provide a unique window to construe the underlying mechanism of the biological systems in health and disease. Recent research evidences suggest that a wide class of diseases appear to degrade the biological complexity and adaptive capacity of the system. Heart rate signals are one of the most important biological signals that have widely been investigated during the last two and half decades. Recent studies suggested that heart rate signals fluctuate in a complex manner. Various entropy based complexity analysis measures have been developed for quantifying the valuable information that may be helpful for clinical monitoring and for early intervention. This study is focused on determining HRV dynamics to distinguish healthy subjects from patients with certain cardiac problems using symbolic time series analysis technique. For that purpose, we have employed recently developed threshold based symbolic entropy to cardiac inter-beat interval time series of healthy, congestive heart failure and atrial fibrillation subjects. Normalized Corrected Shannon Entropy (NCSE) was used to quantify the dynamics of heart rate signals by continuously varying threshold values. A rule based classifier was implemented for classification of different groups by selecting threshold values for the optimal separation. The findings indicated that there is reduction in the complexity of pathological subjects as compared to healthy ones at wide range of threshold values. The results also demonstrated that complexity decreased with disease severity.

  20. 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.

  1. Effects of mindfulness on perceived stress levels and heart rate variability

    OpenAIRE

    Rolph, Gwyneth Wesley

    2017-01-01

    Mindfulness has become increasingly popular as a method for building resilience against stress in both clinical and healthy populations. This study sought to investigate the effects of mindfulness training on perceived levels of stress and heart rate variability in students.

  2. A soy-based phosphatidylserine/ phosphatidic acid complex (PAS) normalizes the stress reactivity of hypothalamus-pituitary-adrenal-axis in chronically stressed male subjects: a randomized, placebo-controlled study.

    Science.gov (United States)

    Hellhammer, Juliane; Vogt, Dominic; Franz, Nadin; Freitas, Ulla; Rutenberg, David

    2014-07-31

    Supplementation with a phosphatidylserine and phosphatidylserine/ phosphatidic acid complex (PAS) has been observed to normalize stress induced dysregulations of the hypothalamus-pituitary-adrenal axis (HPAA). Prolonged stress first induces a hyper-activation of the HPAA, which then can be followed by a state of hypo-activation.The aim of this study was to examine effects of an oral supplementation with 400 mg PS & 400 mg PA (PAS 400) per day on the endocrine stress response (ACTH, saliva and serum cortisol) to a psychosocial stressor. A special focus was to analyze subgroups of low versus high chronically stressed subjects as well as to test efficacy of 200 mg PS & 200 mg PA (PAS 200). 75 healthy male volunteers were enrolled for this double-blind, placebo-controlled study, stratified by chronic stress level, and randomly allocated to one of three study arms (placebo, PAS 200 and PAS 400 per day, respectively). Study supplementation was administered for 42 days for each participant. Chronic stress was measured with the Trier Inventory for Chronic Stress (TICS), and subgroups of high and low chronic stress were differentiated by median values as provided by the TICS authors. A six week period of supplementation was followed by an acute stress test (Trier Social Stress Test - TSST). Chronic stress levels and other baseline measures did not differ between treatment groups (all p>0.05). Acute stress was successfully induced by the TSST and resulted in a hyper-responsivity of the HPAA in chronically stressed subjects. Compared to placebo, a supplementation with a daily dose of PAS 400 was effective in normalizing the ACTH (p=0.010), salivary (p=0.043) and serum cortisol responses (p=0.035) to the TSST in chronically high but not in low stressed subjects (all p>0.05). Compared to placebo, supplementation with PAS 200 did not result in any significant differences in these variables (all p>0.05). There were no significant effects of supplementation with PAS on heart rate

  3. The Mayo Clinic quadratic equation improves the prediction of glomerular filtration rate in diabetic subjects.

    Science.gov (United States)

    Rigalleau, Vincent; Lasseur, Catherine; Raffaitin, Christelle; Perlemoine, Caroline; Barthe, Nicole; Chauveau, Philippe; Combe, Christian; Gin, Henri

    2007-03-01

    Although recommended, both the Cockcroft and Gault formula (CG) and the modification of diet in renal disease (MDRD) equation are not ideally predictive of glomerular filtration rate (GFR) in diabetic subjects; we tested whether the new Mayo Clinic Quadratic (MCQ) equation performed better. In 200 diabetic subjects with a wide range of renal function, GFR was measured by 51Cr-EDTA clearance, and compared with the results of the three predictive equations by regression analysis and Bland and Altman procedures. The correlations with body mass index, age and albumin excretion rates were tested. The precisions (absolute difference as percentage), diagnostic accuracies [receiver operating characteristic (ROC) curves for the diagnosis of moderate and severe chronic kidney disease (CKD)], and the results of stratification according to the KDOQ classification were compared. The CG and MCQ overestimated mean GFR, whereas the MDRD underestimated it. Correlation coefficients and areas under the ROC curves were better for the MDRD and the MCQ as compared with the CG, which was biased by body weight (+30% overestimation in obese diabetic subjects). The absolute differences with true GFR were slightly lower for the MDRD than the MCQ, and both better than the CG. Both the MDRD and MCQ correctly stratified 65% of the subjects (CG: 55%, P<0.05). In contrast with the MDRD, the MCQ did not underestimate normal GFR, and its performance for stratification was uniformly good over a wide GFR range. In diabetic subjects, the MCQ has a similar diagnostic performance to the MDRD, but it does not underestimate normal GFR, which is an important advantage.

  4. COMT Val158Met genotype selectively alters prefrontal [18F]fallypride displacement and subjective feelings of stress in response to a psychosocial stress challenge.

    Directory of Open Access Journals (Sweden)

    Dennis Hernaus

    Full Text Available Catechol-O-methyltransferase (COMT plays an essential role in degradation of extracellular dopamine in prefrontal regions of the brain. Although a polymorphism in this gene, COMT Val(158Met, affects human behavior in response to stress little is known about its effect on dopaminergic activity associated with the human stress response, which may be of interest for stress-related psychiatric disorders such as psychosis. We aimed to investigate the effect of variations in COMT genotype on in vivo measures of stress-induced prefrontal cortex (PFC dopaminergic processing and subjective stress responses. A combined sample of healthy controls and healthy first-degree relatives of psychosis patients (n = 26 were subjected to an [(18F]fallypride Positron Emission Tomography scan. Psychosocial stress during the scan was induced using the Montreal Imaging Stress Task and subjective stress was assessed every 12 minutes. Parametric t-maps, generated using the linear extension of the simplified reference region model, revealed an effect of COMT genotype on the spatial extent of [(18F]fallypride displacement. Detected effects of exposure to psychosocial stress were unilateral and remained restricted to the left superior and right inferior frontal gyrus, with Met-hetero- and homozygotes showing less [(18F]fallypride displacement than Val-homozygotes. Additionally, Met-hetero- and homozygotes experienced larger subjective stress responses than Val-homozygotes. The direction of the effects remained the same when the data was analyzed separately for controls and first-degree relatives. The human stress response may be mediated in part by COMT-dependent dopaminergic PFC activity, providing speculation for the neurobiology underlying COMT-dependent differences in human behaviour following stress. Implications of these results for stress-related psychopathology and models of dopaminergic functioning are discussed.

  5. 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...

  6. The 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 β-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 mortality...

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

    Indian Academy of Sciences (India)

    Behavioural responses to stress can form distinct profiles in a wide range of animals: proactive and reactive profiles or coping styles. Stress responsiveness can also differentiate between the behavioural profiles. The tendency to regain feed intake following transfer to a novel social-isolation tank (the speed of acclimation) ...

  8. Graduating Medical Students' Ratings of Stresses, Pleasures, and Coping Strategies.

    Science.gov (United States)

    Wolf, Thomas M.; And Others

    1988-01-01

    Data on the stress and coping of medical students was gathered in order to design a health promotion and wellness program. A questionnaire was completed by graduating students. Examinations, classwork, and financial responsibilities were considered the three most stressful aspects of medical education. (Author/MLW)

  9. Effect of cobalt chloride on soybean seedlings subjected to cadmium stress

    Directory of Open Access Journals (Sweden)

    Jagna Chmielowska-Bąk

    2014-09-01

    Full Text Available Contamination of the environment with heavy metals such as Cd is a serious problem of modern world. Exposure of plants to Cd leads to oxidative stress, inhibition of respiration and photosynthesis, increased rate of mutation and, as a consequence, stunted growth and yield decrease. One of the common reactions of plants to cadmium stress is over-production of ethylene, however the exact role of this hormone in plants response to Cd is still unrecognized. The aim of the present study is evaluation of the impact of an ethylene synthesis inhibitor, Co, on the response of soybean seedlings to cadmium stress. The experiments included measurements of growth, cell viability, ethylene production and expression of genes associated with cellular signaling in soybean seedlings exposed to CdCl2 (with Cd in a concentration of 223 μM and/or CoCl2 (with Co in concentration of 4.6 μM. Surprisingly, the results show that Co has no effect on ethylene biosynthesis, however, it affects cell viability and expression of Cd-induced genes associated with plant signaling pathways. The affected genes encode mitogen-activated protein kinase kinase2 (MAPKK2, nitrate reductase and DOF1 and bZIP2 transcription factors. The role of Co in plants response to cadmium stress and its potential use as an ethylene inhibitor is discussed.

  10. Annatto carotenoids attenuate oxidative stress and inflammatory response after high-calorie meal in healthy subjects.

    Science.gov (United States)

    Roehrs, Miguel; Conte, Lisiane; da Silva, Dariane Trivisiol; Duarte, Thiago; Maurer, Luana Haselein; de Carvalho, José Antonio Mainardi; Moresco, Rafael Noal; Somacal, Sabrina; Emanuelli, Tatiana

    2017-10-01

    The aim of this study was to evaluate the effect of annatto carotenoids intake associated to a single high-calorie meal (high fat and high carbohydrate) in postprandial biochemical, inflammatory and oxidative stress markers. Twelve healthy subjects (6 men, 6 women) were included in this randomised, controlled crossover study. Baseline blood samples were collected from fasting subjects that immediately received high-calorie meal without carotenoid (placebo) or containing 1.2mg/kg bixin (BIX) or 0.06mg/kg norbixin (NBIX). Blood samples were taken 60, 120 and 240min after meal intake. NBIX intake did not affect biochemical blood markers but reduced the postprandial levels of inflammatory cytokines (IL-1, IL-6 and TNF-α) and lipid oxidation 60-120min after meal. BIX only partially prevented postprandial-induced lipid oxidation. Results indicate that the intake of NBIX may be an alternative to reduce the postprandial inflammatory and oxidative stress responses to high-calorie meals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. 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

  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

    2017-12-07

    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

  13. 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.

  14. 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.

  15. 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.

  16. Predicting Self-Rated Mental and Physical Health: The Contributions of Subjective Socioeconomic Status and Personal Relative Deprivation

    Directory of Open Access Journals (Sweden)

    Mitchell J. Callan

    2015-09-01

    Full Text Available Lower subjective socioeconomic status (SSS and higher personal relative deprivation (PRD relate to poorer health. Both constructs concern people’s perceived relative social position, but they differ in their emphasis on the reference groups people use to determine their comparative disadvantage (national population vs. similar others and the importance of resentment that may arise from such adverse comparisons. We investigated the relative utility of SSS and PRD as predictors of self-rated physical and mental health (e.g., self-rated health, stress, health complaints. Across 6 studies, self-rated physical and mental health were on the whole better predicted by measures of PRD than by SSS while controlling for objective socioeconomic status (SES, with SSS rarely contributing unique variance over and above PRD and SES. Studies 4 to 6 discount the possibility that the superiority of PRD over SSS in predicting health is due to psychometric differences (e.g., reliability or response biases between the measures.

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

    Science.gov (United States)

    Nani, Bruno Dias; Lima, Patricia Oliveira de; Marcondes, Fernanda Klein; Groppo, Francisco Carlos; Rolim, Gustavo Sattolo; Moraes, Antonio Bento Alves de; Cogo-Müller, Karina; Franz-Montan, Michelle

    2017-01-01

    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 stressed group (p stressed subjects.

  18. Subjects for achievement of blast furnace operation with low reducing agent rate

    Energy Technology Data Exchange (ETDEWEB)

    Ujisawa, Y.; Nakano, K.; Matsukura, Y.; Sunahara, K.; Komatsu, S.; Yamamoto, T. [Sumitomo Metal Industry Ltd., Kashima (Japan). Corp R& amp; D Labs.

    2006-12-15

    The technology which reduces the reducing agent rate by the improvement in the reaction efficiency of blast furnace leads to reduction of hot metal manufacturing cost, but also solution of recent CO{sub 2} emission reduction. The subjects for achievement of the blast furnace operation with low reducing agent rate were described on reduction measures of the carbon consumption and problem of the measures referring to the example of reducing agent rate of the present state blast furnace concerning blast operation and reactive improvement. And, carried out concrete measures were introduced in order to aim at the low reducing agent rate operation. The following results were obtained. 1) Since it has reached the already high reaction efficiency in present state blast furnace, it is not easy to attempt further reduction of the reducing agent rate. 2) The blast furnace use of high reactivity coke or reduced iron is equal level or over it in comparison with the reduction effect by the assumed blast operation in this paper. 3) The promotion of coke reaction load with the gasification is worried, when it aims at the low reducing agent rate operation by the high reactivity coke use. 4) It is estimated that the threshold also exists for the reducibility of competing ore, when it aims at the low reducing agent rate operation using the high reactivity coke. 5) The use of the low SiO{sub 2} sinter is effective for the improvement on the permeability in the blast furnace, when it aims at the low fuel rate operation. However, the new technology of the permeability improvement is desired, since there is a limit for low SiO{sub 2} of the sintered ore, when future raw material supply and demand is considered.

  19. Stress response of a clinical Enterococcus faecalis isolate subjected to a novel antimicrobial surface coating.

    Science.gov (United States)

    Clauss-Lendzian, Emanuel; Vaishampayan, Ankita; de Jong, Anne; Landau, Uwe; Meyer, Carsten; Kok, Jan; Grohmann, Elisabeth

    2018-03-01

    Emerging antibiotic resistance among pathogenic bacteria, paired with their ability to form biofilms on medical and technical devices, represents a serious problem for effective and long-term decontamination in health-care environments and gives rise to an urgent need for new antimicrobial materials. Here we present the impact of AGXX ® , a novel broad-spectrum antimicrobial surface coating consisting of micro-galvanic elements formed by silver and ruthenium, on the transcriptome of Enterococcus faecalis. A clinical E. faecalis isolate was subjected to metal stress by growing it for different periods in presence of the antimicrobial coating or silver-coated steel meshes. Subsequently, total RNA was isolated and next-generation RNA sequencing was performed to analyze variations in gene expression in presence of the antimicrobial materials with focus on known stress genes. Exposure to the antimicrobial coating had a large impact on the transcriptome of E. faecalis. After 24min almost 1/5 of the E. faecalis genome displayed differential expression. At each time-point the cop operon was strongly up-regulated, providing indirect evidence for the presence of free Ag + -ions. Moreover, exposure to the antimicrobial coating induced a broad general stress response in E. faecalis. Genes coding for the chaperones GroEL and GroES and the Clp proteases, ClpE and ClpB, were among the top up-regulated heat shock genes. Differential expression of thioredoxin, superoxide dismutase and glutathione synthetase genes indicates a high level of oxidative stress. We postulate a mechanism of action where the combination of Ag + -ions and reactive oxygen species generated by AGXX ® results in a synergistic antimicrobial effect, superior to that of conventional silver coatings. Copyright © 2017 Elsevier GmbH. All rights reserved.

  20. Substances used and prevalence rates of pharmacological cognitive enhancement among healthy subjects.

    Science.gov (United States)

    Franke, Andreas G; Bagusat, Christiana; Rust, Sebastian; Engel, Alice; Lieb, Klaus

    2014-11-01

    Pharmacological "cognitive enhancement" (CE) is defined as the use of any psychoactive drug with the purpose of enhancing cognition, e.g. regarding attention, concentration or memory by healthy subjects. Substances commonly used as CE drugs can be categorized into three groups of drugs: (1) over-the-counter (OTC) drugs such as coffee, caffeinated drinks/energy drinks, caffeine tablets or Ginkgo biloba; (2) drugs being approved for the treatment of certain disorders and being misused for CE: drugs to treat attention-deficit/hyperactivity disorder (ADHD) such as the stimulants methylphenidate (MPH, e.g. Ritalin(®)) or amphetamines (AMPH, e.g. Attentin(®) or Adderall(®)), to treat sleep disorders such as modafinil or to treat Alzheimer's disease such as acetylcholinesterase inhibitors; (3) illicit drugs such as illicit AMPH, e.g. "speed", ecstasy, methamphetamine (crystal meth) or others. Evidence from randomized placebo-controlled trials shows that the abovementioned substances have limited pro-cognitive effects as demonstrated, e.g. regarding increased attention, increased cognitive speed or shortening of reaction times, but on the same time poses considerable safety risks on the consumers. Prevalence rates for the use of CE drugs among healthy subjects show a broad range from less than 1 % up to more than 20 %. The range in prevalence rates estimates results from several factors which are chosen differently in the available survey studies: type of subjects (students, pupils, special professions, etc.), degree of anonymity in the survey (online, face-to-face, etc.), definition of CE and substances used/misused for CE, which are assessed (OTC drugs, prescription, illicit drugs) as well as time periods of use (e.g. ever, during the past year/month/week, etc.). A clear and comprehensive picture of the drugs used for CE by healthy subjects and their adverse events and safety risks as well as comprehensive and comparable international data on the prevalence rates of

  1. Pulsatile Stress in Middle-Aged Patients With Type 1 or Type 2 Diabetes Compared With Nondiabetic Control Subjects

    Science.gov (United States)

    Philips, Jean-Christophe; Marchand, Monique; Scheen, André J.

    2010-01-01

    OBJECTIVE Arterial pulse pressure is considered to be an independent cardiovascular risk factor. We compared pulse pressure during an active orthostatic test in middle-aged patients with type 1 diabetes and with type 2 diabetes and corresponding nondiabetic control subjects. RESEARCH DESIGN AND METHODS Forty patients with type 1 diabetes (mean age 50 years, diabetes duration 23 years, and BMI 23.0 kg/m2) were compared with 40 nonhypertensive patients with type 2 diabetes (respectively, 50 years, 8 years, and 29.7 kg/m2). Patients taking antihypertensive agents or with renal insufficiency were excluded. All patients were evaluated with a continuous noninvasive arterial blood pressure monitoring (Finapres) in standing (1 min), squatting (1 min), and again standing position (1 min). Patients with type 1 or type 2 diabetes were compared with two groups of 40 age-, sex- and BMI-matched healthy subjects. RESULTS Patients with type 1 diabetes and patients with type 2 diabetes showed significantly higher pulse pressure, heart rate, and double product of pulse pressure and heart rate (PP×HR) (type 1: 5,263 vs. 4,121 mmHg/min, P = 0.0004; type 2: 5,359 vs. 4,321 mmHg, P = 0.0023) levels than corresponding control subjects. There were no significant differences between patients with type 1 diabetes and type 2 diabetes regarding pulse pressure (59 vs. 58 mmHg), heart rate (89 vs. 88/min), and PP×HR (5,263 vs. 5,359 mmHg/min). CONCLUSIONS Patients with type 1 diabetes have increased levels of peripheral PP, an indirect marker of arterial stiffness, and PP×HR, an index of pulsatile stress, comparable to those of nonhypertensive patients with type 2 diabetes at similar mean age of 50 years. PMID:20693351

  2. 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

    2017-03-01

    Combining alcohol and caffeine is associated with increased alcohol consumption, but no prospective experimental studies have examined whether added caffeine increases alcohol consumption. This study examined how caffeine alters alcohol self-administration and subjective reinforcing effects in healthy adults. 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). The 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. 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. 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 that 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.

  3. Suboccipital decompression enhances heart rate variability indices of cardiac control in healthy subjects.

    Science.gov (United States)

    Giles, Paul D; Hensel, Kendi L; Pacchia, Christina F; Smith, Michael L

    2013-02-01

    Osteopathic manipulative treatment (OMT) focused on the upper cervical spine is theorized to affect the function of the vagus nerve and thereby influence the parasympathetic branch of the autonomic nervous system. This study was designed to determine the acute effect of upper cervical spine manipulation on cardiac autonomic control as measured by heart rate variability. Nineteen healthy, young adult subjects underwent three different experimental interventions administered in random order: cervical OMT, sham manipulation, and time control. Six minutes of electrocardiographic data were collected before and after each intervention, and heart rate variability was assessed by both time-domain and frequency-domain measures. No differences in resting heart rate or any measure of heart rate variability were observed between the baseline periods prior to each intervention. The OMT protocol resulted in an increase in the standard deviation of the normal-to-normal intervals (0.12±0.082 seconds, p0.11 for all variables). These data support the hypothesis that upper cervical spine manipulation can acutely affect measures of heart rate variability in healthy individuals.

  4. Suboccipital Decompression Enhances Heart Rate Variability Indices of Cardiac Control in Healthy Subjects

    Science.gov (United States)

    Giles, Paul D.; Hensel, Kendi L.; Pacchia, Christina F.

    2013-01-01

    Abstract Objectives Osteopathic manipulative treatment (OMT) focused on the upper cervical spine is theorized to affect the function of the vagus nerve and thereby influence the parasympathetic branch of the autonomic nervous system. This study was designed to determine the acute effect of upper cervical spine manipulation on cardiac autonomic control as measured by heart rate variability. Design Nineteen healthy, young adult subjects underwent three different experimental interventions administered in random order: cervical OMT, sham manipulation, and time control. Six minutes of electrocardiographic data were collected before and after each intervention, and heart rate variability was assessed by both time-domain and frequency-domain measures. Results No differences in resting heart rate or any measure of heart rate variability were observed between the baseline periods prior to each intervention. The OMT protocol resulted in an increase in the standard deviation of the normal-to-normal intervals (0.12±0.082 seconds, p0.11 for all variables). Conclusions These data support the hypothesis that upper cervical spine manipulation can acutely affect measures of heart rate variability in healthy individuals. PMID:22994907

  5. Stress hormone release is a key component of the metabolic response to lipopolysaccharide (LPS): studies in hypopituitary and healthy subjects

    DEFF Research Database (Denmark)

    Bach, Ermina; Møller, Andreas Buch; Jørgensen, Jens Otto Lunde

    2016-01-01

    OBJECTIVE: Lipopolysaccharide (LPS) generates acute and chronic inflammatory and metabolic responses during acute illness and in the pathogenesis of the metabolic syndrome, type 2 diabetes and cardiovascular disease, but it is unclear whether these responses depend on intact pituitary release...... of stress hormones. We compared the metabolic effects of LPS in hypopituitary patients (HP) (in the absence of pituitary stress hormone responses) and healthy control subjects (CTR) (with normal pituitary stress hormone responses). DESIGN: Single blind randomized. METHODS: We compared effects of LPS...

  6. 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)

  7. Convection and evaporation rate of planar liquid films subjected to impulsive superheating

    Science.gov (United States)

    Kimball, J. T.; Hermanson, J. C.; Allen, J. S.

    2010-11-01

    The interfacial stability, convective structure, and evaporation rate of upward-facing, thin liquid films were studied experimentally. Four different working fluids were used. Films initially 5 mm to 100 μm thick were subjected to impulsive superheating. The films resided on a temperature controlled, gold-plated copper surface in a closed, initially degassed test chamber. Superheating was achieved by suddenly dropping the pressure of the saturated pure vapor in the test chamber. The dynamic film thickness was measured at multiple points using ultrasound, and instability wavelength and convective structure information was obtained by schlieren imaging. Considering previous quasi-steady results, the observed convection patterns in many cases suggest an initial, limited penetration of the convection structures into the film. The initial convection patterns and measured evaporation rate in these films are independent of the thermal boundary condition of the substrate. After a sufficiently long time, the convection pattern changes and approaches the previously observed quasi-steady condition.

  8. The effect of time variable stress shadows on rates of induced seismicity (Invited)

    Science.gov (United States)

    Dahm, T.; Becker, D.; Hainzl, S.; Fischer, T.

    2013-12-01

    Stress shadows, i.e. regions where stress is temporarily decreased and not increased, are difficult to identify for natural seismicity, since the overall rate of seismicity is typically small. Fluid injection experiments or mining operations often generate very high rates of induced seismicity, so that stress shadow effects are easily recognized. Well known examples comprise the backfront of seismicity observed during the shut-in phase of hydrofracture experiments, or the Kaiser effect in mining environments if the stress loading is periodic. We present examples of stress shadow effects on induced seismicity. We study the theoretical variation of seismicity rates from time dependent stressing models by means of rate and state frictional models. The controlling parameter are discussed at different reservoir and mining areas, and we discuss the predictability of seismicity rates and decay times. DB has been supported by the German research Foundation under Be4602/1-1.

  9. Biotic patterns of heart rate variation in depressed and psychotic subjects.

    Science.gov (United States)

    Sabelli, H; Messer, J; Kovacevic, L; Walthall, K

    2011-01-01

    This article presents novel quantitative methods to study R to R interval (RRI) series that identify their characteristic pattern of organization, Bios, and their variation in psychiatric illness. In this study twenty-four hour series of RRI were extracted from Holter recordings of healthy subjects (N = 74) and small groups of patients with affective depression or psychosis. These data were analyzed with recurrence and statistical methods. In all subjects, RRI series showed complexes (clusters of recurrences), such as those observed with mathematically-generated biotic series but not in chaotic or random series. RRI series from healthy persons showed diversification (increase in variance with the duration of the series analyzed), novelty (less recurrence isometry than copies randomized by shuffling), causal order (more consecutive isometry than shuffled copies), and asymmetric statistical distribution. These imprints of creative processes are characteristic of mathematical Bios, and are absent in chaos. Bios can be distinguished from random walk series by the nonrandom pattern of the series of differences between heartbeats, as well as by measures of consecutive isometry and of partial autocorrelation. These defining characteristics of Bios are significant signs of health. In comparison with healthy controls, psychiatric patient groups showed more isometry and more consecutive isometry than healthy subjects. Psychiatric patients also showed no diversification. This study highlights the process that produces heart rate variation as being non-stationary and creative (bios, not equilibrium or chaos) and causal (not stochastically generated by the coexistence of multiple factors). These results thus are significant regarding psychiatric health.

  10. Stress-Induced Dopamine Response in Subjects at Clinical High Risk for Schizophrenia with and without Concurrent Cannabis Use

    Science.gov (United States)

    Mizrahi, Romina; Kenk, Miran; Suridjan, Ivonne; Boileau, Isabelle; George, Tony P; McKenzie, Kwame; Wilson, Alan A; Houle, Sylvain; Rusjan, Pablo

    2014-01-01

    Research on the environmental risk factors for schizophrenia has focused on either psychosocial stress or drug exposure, with limited investigation of their interaction. A heightened dopaminergic stress response in patients with schizophrenia and individuals at clinical high risk (CHR) supports the dopaminergic sensitization hypothesis. Cannabis is believed to contribute to the development of schizophrenia, possibly through a cross-sensitization with stress. Twelve CHR and 12 cannabis-using CHR (CHR-CU, 11 dependent) subjects underwent [11C]-(+)-PHNO positron emission tomography scans, while performing a Sensorimotor Control Task (SMCT) and a stress condition (Montreal Imaging Stress task). The simplified reference tissue model was used to obtain binding potential relative to non-displaceable binding (BPND) in the whole striatum, its functional subdivisions (limbic striatum (LST), associative striatum (AST), and sensorimotor striatum (SMST)), globus pallidus (GP), and substantia nigra (SN). Changes in BPND, reflecting alterations in synaptic dopamine (DA) levels, were tested with analysis of variance. SMCT BPND was not significantly different between groups in any brain region (p>0.21). Although stress elicited a significant reduction in BPND in the CHR group, CHR-CU group exhibited an increase in BPND. Stress-induced changes in regional BPND between CHR-CU and CHR were significantly different in AST (p<0.001), LST (p=0.007), SMST (p=0.002), SN (p=0.021), and whole striatum (p=0.001), with trend level in the GP (p=0.099). All subjects experienced an increase in positive (attenuated) psychotic symptoms (p=0.001) following the stress task. Our results suggest altered DA stress reactivity in CHR subjects who concurrently use cannabis, as compared with CHR subjects. Our finding does not support the cross-sensitization hypothesis, which posits greater dopaminergic reactivity to stress in CHR cannabis users, but adds to the growing body of literature showing reduced DA

  11. Reduced synapse and axon numbers in the prefrontal cortex of rats subjected to a chronic stress model for depression

    DEFF Research Database (Denmark)

    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...

  12. 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.

  13. Stress responses of the fish Nile tilapia subjected to electroshock and social stressors

    Directory of Open Access Journals (Sweden)

    R.E. Barreto

    2006-12-01

    Full Text Available Plasma cortisol and glucose levels were measured in 36 adult Nile tilapia males, Oreochromis niloticus (standard length, mean ± SD, 14.38 ± 1.31 cm, subjected to electroshock and social stressors. Pre-stressor levels were determined 5 days after the adjustment of the fish to the experimental aquaria (1 fish/aquarium. Five days later, the effects of stressors on both cortisol and glucose levels were assessed. The following stressors were imposed for 60 min: pairing with a larger resident animal (social stressor, or a gentle electroshock (AC, 20 V, 15 mA, 100 Hz for 1 min every 4 min. Each stressor was tested in two independent groups, one in which stress was quantified immediately after the end of the 60-min stressor imposition (T60 and the other in which stress was quantified 30 min later (T90. Pre-stressor values for cortisol and glucose were not statistically different between groups. Plasma cortisol levels increased significantly and were of similar magnitude for both electroshock and the social stressor (mean ± SD for basal and final samples were: electroshock T60 = 65.47 ± 15.3, 177.0 ± 30.3; T90 = 54.8 ± 16.0, 196.2 ± 57.8; social stress T60 = 47.1 ± 9.0, 187.6 ± 61.7; T90 = 41.6 ± 8.1, 112.3 ± 26.8, respectively. Plasma glucose levels increased significantly for electroshock at both time points (T60 and T90, but only at T90 for the social stressor. Initial and final mean (± SD values are: electroshock T60 = 52.5 ± 9.2, 115.0 ± 15.7; T90 = 35.5 ± 1.1, 146.3 ± 13.3; social stress T60 = 54.8 ± 8.8, 84.4 ± 15.0; T90 = 34.5 ± 5.6, 116.3 ± 13.6, respectively. Therefore, electroshock induced an increase in glucose more rapidly than did the social stressor. Furthermore, a significant positive correlation between cortisol and glucose was detected only at T90 for the social stressor. These results indicate that a fish species responds differently to different stressors, thus suggesting specificity of fish stress response to a

  14. Metabolic clearance rate and blood production rate of testosterone and dihydrotestosterone in normal subjects, during pregnancy, and in hyperthyroidism

    Science.gov (United States)

    Saez, J. M.; Forest, M. G.; Morera, A. M.; Bertrand, J.

    1972-01-01

    The metabolic clearance rate (MCR) and blood production rate (BP) of testosterone (T) and dihydrotestosterone (DHT), the conversion of plasma testosterone to plasma dihydrotestosterone, and the renal clearance of androstenedione, testosterone, and dihydrotestosterone have been studied in man. In eight normal men, the MCRT (516±108 [SD] liters/m2/day) was significantly greater than the MCRDHT (391±71 [SD] liters/m2/day). In seven females, the MCRT (304±53 [SD] liters/m2/day) was also greater than the MCRDHT (209±45 [SD] liters/m2/day) and both values were less than their respective values in men (P hyperthyroidism, the MCR for testosterone and dihydrotestosterone were similar to those observed in pregnant females, but the conversion of testosterone into dihydrotestosterone (2.78±1.7%) (SD) was greater, and similar to that found in men. In men the production of dihydrotestosterone was 0.39±0.1 (SD) mg/day, 50% being derived from the transformation of plasma testosterone. In women the production of DHT was 0.05±0.028 (SD) mg/day, only 10% coming from testosterone. During pregnancy, the production of testosterone and dihydrotestosterone are similar to that in normal women. In three patients with testicular feminization syndrome (an adult with hyperthyroidism and two children) these two MCRs were greatly reduced compared to the normal females, but the conversion of testosterone into dihydrotestosterone was in the limits of normal male range In the normal subjects the renal clearance of androstenedione was greater than that of testosterone and dihydrotestosterone. Less than 20% of the dihydrotestosterone and less than 10% of the androstenedione in the urine is derived from the plasma dihydrotestosterone and androstenedione. PMID:5020435

  15. Vitamin B12 supplementation improves heart rate variability in healthy elderly Indian subjects.

    Science.gov (United States)

    Sucharita, S; Thomas, T; Antony, B; Vaz, M

    2012-05-21

    While vitamin B(12) deficiency is global, data in elderly Indians are lacking. The problem in India is likely to be higher because of vegetarianism and malabsorption related to gastro-intestinal parasites. Autonomic dysfunction is known to occur much earlier in pernicious anemia. However, what is not known is whether these changes are reflected in healthy elderly individuals. This study assessed cardiac sympathetic and parasympathetic activity using heart rate variability (HRV) in healthy elderly individuals of low and high vitamin B(12) status and evaluated the effect of vitamin B(12) supplementation in those with low vitamin B(12) status. 140 elderly subjects aged ≥60 years were screened; 47 healthy subjects were assessed. They underwent blood sampling, anthropometry, HRV and nerve conduction assessment. Subjects were classified based on vitamin B(12) level (148 pmol/L) into deplete vitamin B(12) and replete vitamin B(12) groups. Elderly subjects with low vitamin B(12) status underwent cyanocobalamin supplementation (100 μg) for 3 months. Low frequency (LF) HRV in absolute units was significantly lower in the low vitamin B(12) group. Following supplementation, LF HRV in absolute units and total power rose significantly as compared to pre-supplementation values for the entire supplemented group. In conclusion, elderly with lower vitamin B(12) status have reduced low frequency HRV suggestive of sympathetic involvement. Supplementation with vitamin B(12) for 3 months results in a significant increase in low frequency HRV to values comparable with unsupplemented, but vitamin B(12) replete elderly. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. 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.

  17. Evaluation of changes in birefringence for samples subjected to various stress sources measured with polarization-sensitive OCT

    Science.gov (United States)

    Karnowski, Karol; Li, Qingyun; Villiger, Martin; Sampson, David D.

    2017-04-01

    Polarization-sensitive OCT (PS-OCT) has proven useful in determining the stress-induced birefringence of non-biological materials, but such utility in biological tissues subjected to stress has not been well studied yet. To study stress-induced birefringence of biological tissues, we use a swept-source PS-OCT system with passively depth-encoded, orthogonal polarization states in the illumination path and polarization-diversity detection and a Mueller formalism in post-processing. We present measurements of stress-induced changes in the birefringence of non-biological and biological samples that provide useful benchmarks in further assessing the utility of this approach.

  18. 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

    . Medial longitudinal-arch deformation was measured during walking gait using 3-dimensional gait analysis. Subjects with medial tibial stress syndrome demonstrated a significantly larger navicular drop (mean +/- 1 SD, 7.7 +/- 3.1 mm) and medial longitudinal-arch deformation (5.9 +/- 3.2 degrees) during......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 deformation during quiet standing and gait. Thirty subjects aged 20 to 32 years were included (15 with medial tibial stress syndrome and 15 controls). Navicular drop and medial longitudinal-arch deformation were measured during quiet standing with neutral and loaded foot using a ruler and digital photography...

  19. Survival under stress: molecular mechanisms of metabolic rate ...

    African Journals Online (AJOL)

    Studies in my laboratory are analysing the molecular mechanisms and regulatory events that underlie transitions to and from hypometabolic states In systems including ... Our newest research targets two areas: the role of protein kinases in regulating metabolic adjustments and the role of stress-induced gene expression in ...

  20. Circumferential Notched Tensile Testing for Correlation of the Stress Intensity Factor ( K I ) and Stress Corrosion Crack Growth Rate

    Science.gov (United States)

    Rihan, R.; Singh Raman, R. K.; Ibrahim, R. N.

    2008-07-01

    A novel fracture mechanics technique has been employed for the determination of crack growth rate and threshold stress intensity factor ( K ISCC) for stress corrosion cracking (SCC) using small circumferential notch tensile (CNT) specimens. The technique was applied successfully for testing SCC susceptibility of AISI 1020 mild steel in 12.5 M NaOH at 150 °C. The crack growth rate of mild steel in 12.5 M NaOH solution at 150 °C has been determined at different stress intensity factors ( K I ), and the K ISCC has been determined to be 29 MPa·m1/2. The surfaces of fractured specimens have been examined by scanning electron microscopy (SEM) in order to establish intergranular propagation of stress corrosion cracks. The CNT testing is a simple, relatively fast, and cost-advantageous approach for generating crack growth rate and K ISCC data.

  1. 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

  2. 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.

  3. 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.

  4. Assessment of a new self-rating scale for post-traumatic stress disorder.

    Science.gov (United States)

    Davidson, J R; Book, S W; Colket, J T; Tupler, L A; Roth, S; David, D; Hertzberg, M; Mellman, T; Beckham, J C; Smith, R D; Davison, R M; Katz, R; Feldman, M E

    1997-01-01

    In post-traumatic stress disorder (PTSD) there is a need for self-rating scales that are sensitive to treatment effects and have been tested in a broad range of trauma survivors. Separate measures of frequency and severity may also provide an advantage. Three hundred and fifty-three men and women completed the Davidson Trauma Scale (DTS), a 17-item scale measuring each DSM-IV symptom of PTSD on 5-point frequency and severity scales. These subjects comprised war veterans, survivors of rape or hurricane and a mixed trauma group participating in a clinical trial. Other scales were included as validity checks as follows: Global ratings, SCL-90-R, Eysenck Scale, Impact of Event Scale and Structured Clinical Interview for DSM-III-R. The scale demonstrated good test-retest reliability (r = 0.86), internal consistency (r = 0.99). One main factor emerged for severity and a smaller one for intrusion. In PTSD diagnosed subjects, and the factor structure more closely resembled the traditional grouping of symptoms. Concurrent validity was obtained against the SCID, with a diagnostic accuracy of 83% at a DTS score of 40. Good convergent and divergent validity was obtained. The DTS showed predictive validity against response to treatment, as well as being sensitive to treatment effects. The DTS showed good reliability and validity, and offers promised as a scale which is particularly suited to assessing symptom severity, treatment outcome and in screening for the likely diagnosis of PTSD.

  5. Effect of Magnolia officinalis and Phellodendron amurense (Relora®) on cortisol and psychological mood state in moderately stressed subjects.

    Science.gov (United States)

    Talbott, Shawn M; Talbott, Julie A; Pugh, Mike

    2013-08-07

    Magnolia (Magnolia officinalis) and Phellodendron (Phellodendron amurense) barks are medicinal plants commonly used as traditional remedies for reducing stress and anxiety. Modern dietary supplements are intended to induce relaxation and reduce stress as well as stress-related eating. Previous studies have shown the combination of Magnolia/Phellodendron (MP) to reduce both cortisol exposure and the perception of stress/anxiety, while improving weight loss in subjects with stress-related eating. Competitive athletes are "stressed" by their intense exercise regimens in addition to their normal activities of daily living and thus may benefit from a natural therapy intended to modulate baseline perceptions of stress and stress hormone exposure. We assessed salivary cortisol exposure and psychological mood state in 56 subjects (35 men and 21 women) screened for moderate stress and supplemented with a standardized/patented MP combination (Relora®, Next Pharmaceuticals) or Placebo for 4 weeks. After 4 weeks of supplementation, salivary cortisol exposure was significantly (pStress (-11%), Tension (-13%), Depression (-20%), Anger (-42%), Fatigue (-31%), and Confusion (-27%), and higher indices of Global Mood State (+11%) and Vigor (+18%). These results indicate that daily supplementation with a combination of Magnolia bark extract and Phellodendron bark extract (Relora®) reduces cortisol exposure and perceived daily stress, while improving a variety of mood state parameters, including lower fatigue and higher vigor. These results suggest an effective natural approach to modulating the detrimental health effects of chronic stress in moderately stressed adults. Future studies should examine the possible performance and recovery benefits of Relora supplementation in athletes overstressed by the physical and psychological demands of training and competition.

  6. 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.

  7. Time course of subjective pain ratings, and wound and leg tenderness after hysterectomy

    DEFF Research Database (Denmark)

    Møiniche, S; Dahl, J B; Erichsen, C J

    1997-01-01

    .0002). CONCLUSION: These results indicate that wound pressure algometry correlates to postoperative pain at rest and during movement and may be an alternative way of assessing wound pain and tenderness. Increased tenderness to mechanical stimulation remote from the surgical wound could not be demonstrated.......BACKGROUND: Little information is available on time course of wound tenderness and relationship to subjective pain ratings following surgery. Furthermore, it is not clarified whether surgical procedures may induce hyperalgesia to mechanical stimulation outside the area of the surgical incision. We...... have therefore assessed postoperative pain and pressure pain thresholds (PPT) adjacent to and remote from the surgical incision in 16 patients undergoing hysterectomy. METHODS: Pressure pain threshold was assessed with pressure algometry preoperatively, 4 and 6 and 1, 4 and 8 d after surgery...

  8. Subjective sleep quality in relation to inhibition and heart rate variability in patients with panic disorder.

    Science.gov (United States)

    Hovland, Anders; Pallesen, Ståle; Hammar, Asa; Hansen, Anita Lill; Thayer, Julian F; Sivertsen, Børge; Tarvainen, Mika P; Nordhus, Inger Hilde

    2013-08-15

    Patients with panic disorder (PD) are known to report impaired sleep quality and symptoms of insomnia. PD is an anxiety disorder characterised by deficient physiological regulation as measured by heart rate variability (HRV), and reduced HRV, PD and insomnia have all been related to impaired inhibitory ability. The present study aimed to investigate the interrelationships between subjectively reported sleep impairment, cognitive inhibition and vagally mediated HRV in a sample characterised by variability on measures of all these constructs. Thirty-six patients with PD with or without agoraphobia were included. Cognitive inhibition was assessed with the Color-Word Interference Test from the Delis-Kaplan Executive Function System (D-KEFS), HRV was measured using high frequency (HF) power (ms(2)), and subjectively reported sleep quality was measured with the Pittsburgh Sleep Quality Index (PSQI). Cognitive inhibition was related to both Sleep latency and Sleep disturbances, whereas HRV was only related to Sleep disturbances. These relationships were significant also after controlling for depression. Correlational design. Cognitive inhibition is related to key insomnia symptoms: sleep initiation and sleep maintenance. The data supports the psychobiological inhibition model of insomnia, and extends previous findings. Possible clinical implications of these findings are discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Self-distancing from trauma memories reduces physiological but not subjective emotional reactivity among Veterans with posttraumatic stress disorder.

    Science.gov (United States)

    Wisco, Blair E; Marx, Brian P; Sloan, Denise M; Gorman, Kaitlyn R; Kulish, Andrea L; Pineles, Suzanne L

    2015-11-01

    Self-distancing, or viewing oneself from a third-person perspective, reduces reactivity when analyzing one's feelings. Self-distancing may have important effects among individuals with posttraumatic stress disorder (PTSD), who have heightened emotional and physiological reactivity to trauma memories, but the effects of self-distancing in this group are unclear. We randomly assigned 48 Veterans diagnosed with PTSD to analyze their trauma-related feelings from an immersed (first-person) or distanced (third-person) perspective, and measured physiological and subjective emotional reactivity. Self-distancing during trauma analysis protected against increases in physiological reactivity, such that participants in the immersed condition showed a significant increase in heart rate and skin conductance responses not seen in the distanced condition. However, self-distancing had no effect on self-reported emotional reactivity. Our findings suggest that the effects of self-distancing on subjective emotions may not extend to trauma memories. However, self-distancing during trauma analysis did change physiological reactivity, suggesting at least a short-term benefit for individuals with PTSD.

  10. 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

  11. Differences in stress-related ratings between research center and home environments in dementia caregivers using ecological momentary assessment.

    Science.gov (United States)

    Fonareva, Irina; Amen, Alexandra M; Ellingson, Roger M; Oken, Barry S

    2012-01-01

    Clinicians and researchers working with dementia caregivers typically assess caregiver stress in a clinic or research center, but caregivers' stress is rooted at home where they provide care. This study aimed to compare ratings of stress-related measures obtained in research settings and in the home using ecological momentary assessment (EMA). EMA of 18 caregivers (mean age 66.4 years ±7.8; 89% females) and 23 non-caregivers (mean age 66.4 years ±7.9; 87% females) was implemented using a personal digital assistant. Subjects rated their perceived stress, fatigue, coping with current situation, mindfulness, and situational demand once in the research center and again at 3-4 semi-random points during a day at home. The data from several assessments conducted at home were averaged for statistical analyses and compared with the data collected in the research center. The testing environment had a differential effect on caregivers and non-caregivers for the ratings of perceived stress (p dementia caregivers.

  12. 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

  13. Heart rate variability in normotensive subjects with family history of hypertension.

    Science.gov (United States)

    Muralikrishnan, Krishnan; Balasubramanian, Kabali; Rao, Badanidiyur Viswanatha

    2011-01-01

    Hypertension (HT) is a major silent disease affecting young people because of their hereditary and modern lifestyles. Target organ damages occur before overt hypertension is diagnosed. Many offspring of HT parents show early changes in their cardiovascular autonomic functions. Heart rate variability (HRV) provides a window to understand the cardiac autonomic balance. This study was designed to quantify and to compare the HRV among the normotensive young male offspring without history of parenteral hypertension & diabetic (control group, n = 25, age 20.8 +/- 2.4, BMI 24.4 +/- 3.1) with parenteral history of hypertension & non diabetic (study group n = 25, age 19.7 +/- 1.9, 24.05 +/- 3.5). Blood pressure, heart rate (HR), indices of short term HRV during supine rest and quiet standing, HR variation during timed controlled deep breathing was compared between the two groups. There were significant difference in low frequency (LF) power, HF power, total power. LF and HF expressed also in normalized units at rest and standing. In time domain standard deviation of normal to normal RR interval (SDNN) at supine rest and standing were significant. Respiratory sinus arrthymia (RSA), HF in normalized units, deep breathing difference (BDD) and the ratio of maximum RR to minimum RR were also significant in the control group than study group. In the present study there was an increased sympathetic and decreased parasympathetic activity in the study group. These findings are an early marker of cardiovascular autonomic impairment in subjects with parenteral history of hypertension.

  14. An investigation of interfacial stresses in adhesively-bonded single lap joints subject to transverse pulse loading

    Science.gov (United States)

    Nwankwo, E.; Soleiman Fallah, A.; Louca, L. A.

    2013-04-01

    Debonding in adhesively-bonded lap joints is a detrimental failure mode contingent upon the level of stresses develped in the adhesive. In this work, an analytical model is developed to estimate the peel and shear stresses in an isotropic elastic adhesive in a single lap joint subjected to transverse pulse loads. The proposed analytical model is an extension of the mathematical models developed by He and Rao (Journal of Sound and Vibration 152 (3), (1992) 405-416, 417-425) to study the coupled transverse and longitudinal vibrations of a bonded lap joint system. The adhesive, in this work, is modelled as an elastic isotropic material implemented in Abaqus 6.9-1. The interfacial stresses obtained by finite element simulations were used to validate the proposed analytical model. The maximum peel and shear stresses in the adhesive as predicted by the analytical model were found to correlate well with the maximum stresses predicted by the corresponding numerical models. The peel stresses in the adhesive were found to be higher than shear stresses, a result which is consistent with intuition for transversally loaded joints. The analytical model is able to predict the maxium stresses in the edges where debonding initiates due to the highly asymetrical stress distribution as observed in the finite element simulations and experiment. This phenomenon is consistent with observations made by Vaidya et al. (International Journal of Adhesion & Adhesives 26 (2006) 184-198). The stress distribution under uniformily distributed transverse pulse loading was observed to be similarly asymetric.

  15. 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.

  16. The response of endocrine system to stress loads during space flight in human subject

    Science.gov (United States)

    Macho, L.; Koška, J.; Kšinantová, L.; Pacak, K.; Hoff, T.; Noskov, V. B.; Grigoriev, A. I.; Vigaš, M.; Kvetňanský, R.

    The responses of endocrine system to the exposure to stress-work load and hormonal changes during oral glucose tolerance tests were studied in the Slovak astronaut before (three weeks before flight), during (on the 4th and the 6th days of space flight), and after space flight (1-3 days and 15-17 days after space flight) on board of space station MIR. Blood samples during the tests were collected via cannula inserted into cubital vein, centrifuged in the special appliance Plasma-03, frozen in Kryogem-03, and at the end of the 8-day space flight transforred to Earth in special container for hormonal analysis. Preflight workload produced an increase of plasma norepinephrine and a moderate elevation of epinephrine levels. Plasma levels of insulin, growth hormone, prolactin and cortisol were not markedly changed immediately or 10 min after the end of work load. The higher increases of plasma growth hormone, prolactin and catecholamine levels were noted after workload during space flight as compared to preflight response. The higher plasma glucose and insulin levels were noted during the oral glucose tolerance test in space flight and also in the post flight period. Plasma epinephrine levels were slightly decreasing during glucose tolerance test; however, plasma norepinephrine levels were not changed. The similar patterns of catecholamine levels during glucose tolerance test were found when compared the preflight, in-flight and post flight values. These data demonstrate the changes of the dynamic responses of endocrine system to stress-work and metabolic loads during space flight in human subject.

  17. High-Temperature Slow Crack Growth of Silicon Carbide Determined by Constant-Stress-Rate and Constant-Stress Testing

    Science.gov (United States)

    Choi, Sung H.; Salem, J. A.; Nemeth, N. N.

    1998-01-01

    High-temperature slow-crack-growth behaviour of hot-pressed silicon carbide was determined using both constant-stress-rate ("dynamic fatigue") and constant-stress ("static fatigue") testing in flexure at 1300 C in air. Slow crack growth was found to be a governing mechanism associated with failure of the material. Four estimation methods such as the individual data, the Weibull median, the arithmetic mean and the median deviation methods were used to determine the slow crack growth parameters. The four estimation methods were in good agreement for the constant-stress-rate testing with a small variation in the slow-crack-growth parameter, n, ranging from 28 to 36. By contrast, the variation in n between the four estimation methods was significant in the constant-stress testing with a somewhat wide range of n= 16 to 32.

  18. Nitric oxide and regulation of heart rate in patients with postural tachycardia syndrome and healthy subjects.

    Science.gov (United States)

    Gamboa, Alfredo; Okamoto, Luis E; Raj, Satish R; Diedrich, André; Shibao, Cyndya A; Robertson, David; Biaggioni, Italo

    2013-02-01

    The objective is to study the role of nitric oxide (NO) on cardiovascular regulation in healthy subjects and postural tachycardia syndrome (POTS) patients. Reduced neuronal NO function, which could contribute to a hyperadrenergic state, and increased NO-induced vasodilation, which could contribute to orthostatic intolerance, have been reported in POTS. In protocol 1, 13 healthy volunteers (33 ± 3 years) underwent autonomic blockade with trimethaphan and were administered equipressor doses of Nω-monomethyl-L-arginine (L-NMMA, a NO synthase inhibitor) and phenylephrine to determine the direct chronotropic effects of NO (independent of baroreflex modulation). In protocol 2, we compared the effects of L-NMMA in 9 POTS patients (31 ± 3 years) and 14 healthy (32 ± 2 years) volunteers, during autonomic blockade. During autonomic blockade, L-NMMA and phenylephrine produced similar increases in systolic blood pressure (27 ± 2 versus 27 ± 3 mm Hg). Phenylephrine produced only minimal heart rate changes, whereas L-NMMA produced a modest, but significant, bradycardia (-0.8 ± 0.4 versus -4.8 ± 1.2 bpm; P=0.011). There were no differences between POTS and healthy volunteers in the systolic blood pressure increase (22 ± 2 and 28 ± 5 mm Hg) or heart rate decrease (-6 ± 2 and -4 ± 1 bpm for POTS and controls, respectively) produced by L-NMMA. In the absence of baroreflex buffering, inhibition of endogenous NO synthesis results in a significant bradycardia, reflecting direct tonic modulation of heart rate by NO in healthy individuals. We found no evidence of a primary alteration in NO function in POTS. If NO dysfunction plays a role in POTS, it is through its interaction with the autonomic nervous system.

  19. 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.

  20. Meditation and college students' self-actualization and rated stress.

    Science.gov (United States)

    Janowiak, J J; Hackman, R

    1994-10-01

    This paper concerns the efficacy of meditation and relaxation in promoting self-actualization and changes in self-reported stress among 62 college students. Two groups were given mantra meditation and a yogic relaxation technique referred to as Shavasana. Pre- and posttest measures were taken on the Personal Orientation Inventory and the Behavioral Relaxation Scale. Both groups showed significant increases in scores on self-actualization; however, no differences were found between groups. Meditation training was associated with larger gains in scores on measures of systematic relaxed behavior than of the relaxation training.

  1. Stress Level of Dental and Medical Students: Comparison of Effects of a Subject-Based Curriculum versus a Case-Based Integrated Curriculum.

    Science.gov (United States)

    Ahmad, Fatemah A; Karimi, Anfal A; Alboloushi, Naela A; Al-Omari, Qasem D; AlSairafi, Fatimah J; Qudeimat, Muawia A

    2017-05-01

    The aim of this study was to investigate the stress level of medical and dental students at Kuwait University after a case-based integrated curriculum replaced the former subject-based curriculum. A modified version of the Dental Environment Stress questionnaire was used to measure possible stressors for both medical and dental students. The investigators administered the questionnaire for the first time in 2008, when Kuwait University medical and dental schools followed a subject-based curriculum (group A). The same questionnaire was administered for a second time in 2014, when both medical and dental schools had adopted a case-based integrated curriculum (group B). A total of 345 fifth- and sixth-year medical and dental students responded to the questionnaire (group A=187, group B=158), with an overall 83% response rate. The results showed that, for both the dental and medical students, changing to a case-based integrated curriculum raised the stress level for most of the stressors evaluated. "Inconsistency of feedback on work between different instructors," "difficulties in communicating with teaching staff," "amount of assigned class work," and "examinations and grades" were some of the statistically significant stressors for group B students. Female students reported higher levels of stress than male students in both groups. These results suggest that introducing stress management education into the case-based integrated dental and medical curricula could enhance students' psychological well-being.

  2. 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.

  3. Influence of arotinolol hydrochloride on heart rate spectrum in hypertensive subjects.

    Science.gov (United States)

    Harasawa, Y; Imaizumi, T; Ando, S; Masaki, H; Harada, S; Momohara, M; Takeshita, A

    1994-05-01

    Influence of arotinolol hydrochloride and atenolol on the balance between the sympathetic and parasympathetic nervous systems was evaluated in 8 hypertensive subjects by spectral analysis of heart rate (HR) and systemic blood pressure (BP). Before and after administration of either arotinolol (n = 7) or atenolol (n = 7) for 2 weeks, BP was continuously and non-invasively monitored by a finger-cuff manometry (Finapres). A time series of instantaneous HR was constructed from the BP signal. A time series of mean BP was also constructed. Spectral analysis was performed by the use of an autoregressive algorithm on these time series (approximately 180 sec). Each spectrum was subdivided into low-(0.05-0.15 Hz, LF) and high-frequency (0.15-0.4 Hz, HF) components, and each component was divided by the sum of the two for normalization. As a measure of the balance between the sympathetic and parasympathetic nervous systems, the ratio of LF to HF (LF/HF) was evaluated. Arotinolol increased fractional HF in the HR spectrum from 0.45 +/- 0.12 to 0.73 +/- 0.08 (p < 0.01) and decreased fractional LF from 0.55 +/- 0.12 to 0.27 +/- 0.08 (p < 0.01); consequently, it decreased LF/HF from 1.4 +/- 0.5 to 0.4 +/- 0.2 (p < 0.01). Atenolol had similar effects on these parameters. Neither of these beta-adrenergic blockades produced a discernible decrease in LF/HF in the BP spectrum. In conclusion, these beta-adrenergic blockades decreased LF/HF in the HR spectrum in hypertensive subjects, which suggests that they improved the balance between the sympathetic and parasympathetic nervous systems.

  4. 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.

  5. 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 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.

  6. 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.

  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

    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. 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.

  9. 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

  10. Myotubes from severely obese type 2 diabetic subjects accumulate less lipids and show higher lipolytic rate than myotubes from severely obese non-diabetic subjects.

    Directory of Open Access Journals (Sweden)

    Siril S Bakke

    Full Text Available About 80% of patients with type 2 diabetes are classified as overweight. However, only about 1/3 of severely obese subjects have type 2 diabetes. This indicates that several severely obese individuals may possess certain characteristics that protect them against type 2 diabetes. We therefore hypothesized that this apparent paradox could be related to fundamental differences in skeletal muscle lipid handling. Energy metabolism and metabolic flexibility were examined in human myotubes derived from severely obese subjects without (BMI 44±7 kg/m2 and with type 2 diabetes (BMI 43±6 kg/m2. Lower insulin sensitivity was observed in myotubes from severely obese subjects with type 2 diabetes. Lipolysis rate was higher, and oleic acid accumulation, triacylglycerol content, and fatty acid adaptability were lower in myotubes from severely obese subjects with type 2 diabetes compared to severely obese non-diabetic subjects. There were no differences in lipid distribution and mRNA and protein expression of the lipases HSL and ATGL, the lipase cofactor CGI-58, or the lipid droplet proteins PLIN2 and PLIN3. Glucose and oleic acid oxidation were also similar in cells from the two groups. In conclusion, myotubes established from severely obese donors with established type 2 diabetes had lower ability for lipid accumulation and higher lipolysis rate than myotubes from severely obese donors without diabetes. This indicates that a difference in intramyocellular lipid turnover might be fundamental in evolving type 2 diabetes.

  11. Strain Rate Dependent Deformation of a Polymer Matrix Composite with Different Microstructures Subjected to Off-Axis Loading

    National Research Council Canada - National Science Library

    Zhu, Xiaojun; Chen, Xuefeng; Zhai, Zhi; Yang, Zhibo; Li, Xiang; He, Zhengjia

    2014-01-01

    ... are often subjected to complex loadings under extreme circumstances [3, 4] in which the properties of the PMCs exhibit highly nonlinear and rate dependence, so it is necessary for structural design and an...

  12. Physical Activity, Mindfulness Meditation, or Heart Rate Variability Biofeedback for Stress Reduction: A Randomized Controlled Trial

    OpenAIRE

    van der Zwan, Judith Esi; de Vente, Wieke; Huizink, Anja C.; B?gels, Susan M.; de Bruin, Esther 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 stress and its related symptoms. We randomly allocated 126 participants to PA, MM, or HRV-BF upon enrollment, of whom 76 agreed to participate. The interventions consisted of psycho-education and a...

  13. The synchronous Generators Rated Speed’s Influence on electromagnetic Stresses and on Costs

    OpenAIRE

    Elisabeta Spunei; Laurenţiu Pădeanu; Florina Piroi; Ion Piroi; Gheorghe Liuba

    2013-01-01

    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 t...

  14. Stress Symptoms among Adolescents: The Role of Subjective Psychosocial Conditions, Lifestyle, and Self-Esteem

    Science.gov (United States)

    Schraml, Karin; Perski, Aleksander; Grossi, Giorgio; Simonsson-Sarnecki, Margareta

    2011-01-01

    Stress-related problems are increasing among Swedish adolescents, especially among females. The aims of this study were to survey the incidence of stress symptoms among 16-year-olds, to investigate the related gender differences, and to understand the factors that may contribute to stress symptoms. The study is questionnaire based, and the sample…

  15. Effects of short and prolonged transcutaneous vagus nerve stimulation on heart rate variability in healthy subjects.

    Science.gov (United States)

    De Couck, M; Cserjesi, R; Caers, R; Zijlstra, W P; Widjaja, D; Wolf, N; Luminet, O; Ellrich, J; Gidron, Y

    2017-03-01

    The vagus nerve is strategically located in the body, and has multiple homeostatic and health-promoting effects. Low vagal activity predicts onset and progression of diseases. These are the reasons to activate this nerve. This study examined the effects of transcutaneous vagus nerve stimulation (t-VNS) on a main index of vagal activity, namely heart rate variability (HRV). In Study 1, we compared short (10min) left versus right ear t-VNS versus sham (no stimulation) in a within-subjects experimental design. Results revealed significant increases in only one HRV parameter (standard deviation of the RR intervals (SDNN)) following right-ear t-VNS. Study 2 examined the prolonged effects of t-VNS (1h) in the right ear. Compared to baseline, right-t-VNS significantly increased the LF and LF/HF components of HRV, and SDNN in women, but not in men. These results show limited effects of t-VNS on HRV, and are discussed in light of neuroanatomical and statistical considerations and future directions are proposed. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Discrimination of multiple stress levels in virtual reality environments using heart rate variability.

    Science.gov (United States)

    Jinsil Ham; Dongrae Cho; Jooyoung Oh; Boreom Lee

    2017-07-01

    People are suffering from various stress during daily living. Stress can cause a variety of symptoms, and in severe cases, it can lead to a dangerous disease. For this reason, it is essential to develop a simple method to evaluate stress level precisely. Popularly, heart rate variability (HRV) is used because it can reflect autonomic nervous system (ANS) activity. On the other hand, virtual reality (VR), which can provide environments similar to reality, is widely used in laboratory-based experiments. In this paper, we analyzed the HRV of healthy people by using the photoplethysmogram (PPG) while providing diverse stress situations. To detect and classify the exact stress levels, extracted HRV features and linear discriminant analysis (LDA) were utilized. As a result, high multi-class classification accuracy was obtained: Baseline (74%), mild stress (81%), and severe stress (82%).

  17. 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.

  18. Effect of Stress-free Therapy on Cerebral Blood Flow: Comparisons among patients with metabolic cardiovascular disease, healthy subjects and placebo-treated subjects

    Science.gov (United States)

    Ryotokuji, Kenji; Ishimaru, Keisou; Kihara, Kazuhiko; Namiki, Yoshihisa; Nakashima, Takuma; Otani, Satoru

    2014-01-01

    Background and aims: We have developed a Stress-free Therapy® device wherein “Pinpoint Plantar Long-wavelength Infrared Light Irradiation (PP-LILI)” increases peripheral-deep body temperature and blood flow volume and stabilizes blood pressure as well as significantly reduces stress hormones such as adrenocorticotrophic hormone and cortisol without using drugs. Moreover, we have found this therapy to significantly improve blood glucose and insulin resistance in patients with type 2 diabetes. Based on this background of clinical efficacy, we validated changes in cerebral blood flow in patients with metabolic cardiovascular disease and examined the efficacy of Stress-free Therapy® on cerebral blood flow as compared to that in healthy control subjects and placebo-treated patients. Results: The change in cerebral blood flow volume during 15-minute PP-LILI was 5.1 ± 1.8 mL/min in patients with metabolic cardiovascular disease, showing a significant increase (P<0.05) of 3.1 mL/min as compared with the mean blood flow value after resting for 15 minutes. Conclusions: Our results suggested Stress-free Therapy® to significantly increase cerebral blood flow, possibly leading to the prevention of metabolic cardiovascular disease. PMID:24771966

  19. Schisandra chinensis and Rhodiola rosea exert an anti-stress effect on the HPA axis and reduce hypothalamic c-Fos expression in rats subjected to repeated stress.

    Science.gov (United States)

    Xia, Nan; Li, Jie; Wang, Hongwei; Wang, Jian; Wang, Yangtian

    2016-01-01

    The aim of the present study was to investigate the effects of Schisandra chinensis (S. chinensis) and Rhodiola rosea (R. rosea) on rats subjected to 5 h of stress, induced by water-floating followed by treadmill exercise. Hypothalamus-pituitary-adrenal (HPA) activity and c-Fos and Fos-related antigen 2 (Fra-2) mRNA expression levels in the hypothalamus of the rats were evaluated. Rats were distributed into four groups: S. chinensis (n=12), R. rosea (n=10), stress control (n=10) and quiet control (n=8). Following a training period of 6 consecutive days, the S. chinensis, R. rosea and stress control groups underwent a 3-h water-floating session in the presence of feline predators immediately followed by 2 h treadmill running to induce psychological and physical stress. Following compound stress induction, the serum levels of corticosterone (CORT), adrenocorticotropic hormone and interleukin-1β and the mRNA expression levels of hypothalamic corticotropin-releasing hormone (CRH), neuropeptide-Y, c-Fos and Fra-2 were evaluated using enzyme-linked immunosorbent assay, radioimmunoassay and quantitative polymerase chain reaction, respectively. The results indicated that S. chinensis and R. rosea markedly decreased the stress-induced elevation of CRH and peripheral CORT levels. The mRNA expression levels of c-Fos and Fra-2 in the hypothalamus were significantly increased after 5 h compound stress, and reduced levels of c-Fos expression were detected in rats treated with R. rosea. Thus, S. chinensis and R. rosea exert an anti-stress effect in rats subjected to stress by balancing the HPA axis, and possibly by reducing the expression of c-Fos in the hypothalamus.

  20. 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

  1. 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...

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

    Indian Academy of Sciences (India)

    Unknown

    Abstract. 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.

  3. Hardening in Two-Phase Materials. II. Plastic Strain and Mean Stress Hardening Rate

    DEFF Research Database (Denmark)

    Lilholt, Hans

    1977-01-01

    The strain parameters which are relevant in a tensile experiment, are analysed and related to the geometry of deformation and to the mean stress of two-phase materials. The hardening rate of the mean stress with respect to plastic strain is found to be useful in comparison between experiments...

  4. 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 ...

  5. 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

    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...... 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...

  6. Modeling baroreflex regulation of heart rate during orthostatic stress

    DEFF Research Database (Denmark)

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

    2006-01-01

    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....... 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...... validate our model against clinical data it is necessary to include the vestibulo-sympathetic reflex. Furthermore our model reveals that the transfer between the nerve firing and blood pressure is non-linear and follows a hysteresis curve. In healthy young people, the hysteresis loop is wide, while...

  7. 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

  8. Stress corrosion cracking of alloy 600 using the constant strain rate test

    Energy Technology Data Exchange (ETDEWEB)

    Bulischeck, T. S.; van Rooyen, D.

    1980-01-01

    The most recent corrosion problems experienced in nuclear steam generators tubed with Inconel alloy 600 is a phenomenon labeled ''denting''. Denting has been found in various degrees of severity in many operating pressurized water reactors. Laboratory investigations have shown that Inconel 600 exhibits intergranular SCC when subjected to high stresses and exposed to deoxygenated water at elevated temperatures. A research project was initiated at Brookhaven National Laboratory in an attempt to improve the qualitative and quantitative understanding of factors influencing SCC in high temperature service-related environments. An effort is also being made to develop an accelerated test method which could be used to predict the service life of tubes which have been deformed or are actively denting. Several heats of commercial Inconel 600 tubing were procured for testing in deaerated pure and primary water at temperatures from 290 to 365/sup 0/C. U-bend type specimens were used to determine crack initiation times which may be expected for tubes where denting has occurred but is arrested and provide baseline data for judging the accelerating effects of the slow strain rate method. Constant extension rate tests were employed to determine the crack velocities experienced in the crack propagation stage and predict failure times of tubes which are actively denting. 8 refs., 17 figs., 5 tabs.

  9. Crustal Stress and Strain Energy Density Rates in South Korea Deduced from GPS Observations

    Directory of Open Access Journals (Sweden)

    Shuanggen Jin Pil-Ho Park

    2006-01-01

    Full Text Available An accurate measurement and understanding of horizontal stress rates within the earth¡¦s crust is important for providing fundamental insights into the mechanisms driving plate motion and intraplate tectonic activity. In this paper, the stress field within the crust of the South Korean peninsula is obtained from observed displacement rates based on 4-year continuous GPS observations (2000 - 2004. Results show that the South Korean peninsula is under both compression and extensional stress regimes with maximum shear stress rate being in the mid part of the study area coinciding with the geologically defined Honam Shear Zone (HSZ and relatively highly seismically active zone. In addition, the variation rate of strain energy density, an important index reflecting the intensity of crustal activity, is further derived, and its distribution indicates high earthquake potential in the mid-part as well as the north and northeast edges of the crust of the South Korean peninsula.

  10. 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.

  11. 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.

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

    Science.gov (United States)

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

    2015-02-01

    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.

  13. 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.

  14. Heart rate variability metrics for fine-grained stress level assessment.

    Science.gov (United States)

    Pereira, Tânia; Almeida, Pedro R; Cunha, João P S; Aguiar, Ana

    2017-09-01

    In spite of the existence of a multitude of techniques that allow the estimation of stress from physiological indexes, its fine-grained assessment is still a challenge for biomedical engineering. The short-term assessment of stress condition overcomes the limits to stress characterization with long blocks of time and allows to evaluate the behaviour change in real-world settings and also the stress level dynamics. The aim of the present study was to evaluate time and frequency domain and nonlinear heart rate variability (HRV) metrics for stress level assessment using a short-time window. The electrocardiogram (ECG) signal from 14 volunteers was monitored using the Vital JacketTM while they performed the Trier Social Stress Test (TSST) which is a standardized stress-inducing protocol. Window lengths from 220 s to 50 s for HRV analysis were tested in order to evaluate which metrics could be used to monitor stress levels in an almost continuous way. A sub-set of HRV metrics (AVNN, rMSSD, SDNN and pNN20) showed consistent differences between stress and non-stress phases, and showed to be reliable parameters for the assessment of stress levels in short-term analysis. The AVNN metric, using 50 s of window length analysis, showed that it is the most reliable metric to recognize stress level across the four phases of TSST and allows a fine-grained analysis of stress effect as an index of psychological stress and provides an insight into the reaction of the autonomic nervous system to stress. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Oxidative Stress Is Associated with an Increased Antioxidant Defense in Elderly Subjects: A Multilevel Approach

    Science.gov (United States)

    Flores-Mateo, Gemma; Elosua, Roberto; Rodriguez-Blanco, Teresa; Basora-Gallisà, Josep; Bulló, Mònica; Salas-Salvadó, Jordi; Martínez-González, Miguel Ángel; Estruch, Ramon; Corella, Dolores; Fitó, Montserrat; Fiol, Miquel; Arós, Fernando; Gómez-Gracia, Enrique; Subirana, Isaac; Lapetra, José; Ruiz-Gutiérrez, Valentina; Sáez, Guillermo T.; Covas, Maria-Isabel

    2014-01-01

    Background Studies of associations between plasma GSH-Px activity and cardiovascular risk factors have been done in humans, and contradictory results have been reported. The aim of our study was to assess the association between the scavenger antioxidant enzyme glutathione peroxidase (GSH-Px) activity in plasma and the presence of novel and classical cardiovascular risk factors in elderly patients. Methods We performed a cross-sectional study with baseline data from a subsample of the PREDIMED (PREvención con DIeta MEDiterránea) study in Spain. Participants were 1,060 asymptomatic subjects at high risk for cardiovascular disease (CVD), aged 55 to 80, selected from 8 primary health care centers (PHCCs). We assessed classical CVD risk factors, plasma oxidized low-density lipoproteins (ox-LDL), and glutathione peroxidase (GSH-Px) using multilevel statistical procedures. Results Mean GSH-Px value was 612 U/L (SE: 12 U/L), with variation between PHCCs ranging from 549 to 674 U/L (Variance = 1013.5; P<0.001). Between-participants variability within a PHCC accounted for 89% of the total variation. Both glucose and oxidized LDL were positively associated with GSH-Px activity after adjustment for possible confounder variables (P = 0.03 and P = 0.01, respectively). Conclusion In a population at high cardiovascular risk, a positive linear association was observed between plasma GSH-Px activity and both glucose and ox-LDL levels. The high GSH-Px activity observed when an oxidative stress situation occurred, such as hyperglycemia and lipid oxidative damage, could be interpreted as a healthy defensive response against oxidative injury in our cardiovascular risk population. PMID:25269026

  16. Influence of transient strain rates on material flow stress and microstructure evolution

    Science.gov (United States)

    Dierdorf, Jens; Lohmar, Johannes; Hirt, Gerhard

    2017-10-01

    A comprehensive knowledge about the material flow stress is a key parameter for a reliable design of hot forming processes using Finite Element (FE) software codes. Due to the microstructure evolution caused by the interaction of hardening and softening phenomena that take place during hot forming operations, the material flow stress is influenced by strain rate and temperature. While transient strain rates and temperatures typically characterize the industrial forming processes, the flow curves used in FE simulations are normally determined at arbitrary constant temperatures and strain rates. To calculate the flow stress evolution in between the measured strain rates, FE programs use linear interpolation. Hence, the material relaxation behavior caused by the microstructure evolution during transient strain rates is not considered. Previous investigations by various authors have shown that for a rapid strain rate change by one order of magnitude significant deviations between measured flow stress and linear interpolation appear before the flow stress approximates the flow curve obtained at the new constant strain rate again. However as mentioned before, industrial forming processes are characterized by more or less smooth than instantaneous changes in strain rate. Therefore, in this study, changing strain rates with different linear slopes are investigated. For this purpose, isothermal cylinder compression tests of an industrial case hardening steel are conducted at elevated temperatures. The resulting flow stress is compared with the linear interpolation of the flow curves determined at constant strain rates. Additionally, the grain size evolution during the strain rate change is analyzed to better understand the microstructural changes. The current investigation shows that the slope of the strain rate increase significantly influences the deviation from the linear interpolation. This observation can be explained by the time dependent microstructure evolution

  17. Load rating and retrofit testing of bridge timber piles subjected to eccentric loading.

    Science.gov (United States)

    2012-11-01

    This report first evaluated the load rating procedure currently in use by the Illinois Department of Transportation (IDOT) for rating timber : piles supporting multiple-span, simply supported bridges. For simplicity, these piles are often rated under...

  18. 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.

  19. Consequences of untreated posttraumatic stress disorder following war in former Yugoslavia: morbidity, subjective quality of life, and care costs.

    Science.gov (United States)

    Priebe, Stefan; Matanov, Aleksandra; Janković Gavrilović, Jelena; McCrone, Paul; Ljubotina, Damir; Knezević, Goran; Kucukalić, Abdulah; Francisković, Tanja; Schützwohl, Matthias

    2009-10-01

    To assess long-term mental health outcomes in people who suffer from war-related posttraumatic stress disorder (PTSD) but do not receive appropriate treatment. We interviewed 264 subjects from former Yugoslavia, who lived in Croatia, Serbia, Germany, and the United Kingdom. All of them had suffered from PTSD at some point following the war, but never received psychiatric or psychological treatment. The interviews took place on average 10.7+/-3.0 years after the war-related trauma. Outcomes were current PTSD on the Clinician Administered PTSD Scale for Diagnostic and Statistical Manual of Mental Disorders-IV, subjective quality of life (SQOL) on the Manchester Short Assessment of Quality of Life, and care costs. Socio-demographic characteristics, the level of traumatic war-events, and aspects of the post-war situation were tested for association with outcomes. Current PTSD was diagnosed in 83.7% of participants, the mean SQOL score was 4.0+/-0.9, and mean care costs in the last 3 months exceeded euro1100 in each center. Older age, more traumatic war-events, lower education, and living in post-conflict countries were associated with higher rates of current PTSD. Older age, combat experience, more traumatic war-events, being unemployed, living alone, being housed in collective accommodation, and current PTSD were independently associated with lower SQOL. Older age and living in Germany were linked to higher costs of formal care. People with untreated war-related PTSD have a high risk of still having PTSD a decade after the traumatic event. Their SQOL is relatively low, and they generate considerable care costs. Factors that have been reported as influencing the occurrence of PTSD also appear relevant for recovery from PTSD. Current PTSD may impair SQOL independently of social factors.

  20. Anti-stress effect of theanine on students during pharmacy practice: positive correlation among salivary α-amylase activity, trait anxiety and subjective stress.

    Science.gov (United States)

    Unno, Keiko; Tanida, Naoki; Ishii, Naoto; Yamamoto, Hiroyuki; Iguchi, Kazuaki; Hoshino, Minoru; Takeda, Atsushi; Ozawa, Hayato; Ohkubo, Tsutomu; Juneja, Lekh Raj; Yamada, Hiroshi

    2013-10-01

    Theanine, an amino acid in tea, has significant anti-stress effect on experimental animals under psychosocial stress. Anti-stress effect of theanine on humans was evaluated in 5th-year university students during pharmacy practice. The study design was a single-blind group comparison and participants (n=20) were randomly assigned to theanine or placebo groups. Theanine or placebo (lactose) tablets (200 mg, twice a day, after breakfast and lunch) were taken from 1 week prior to the pharmacy practice and continued for 10 days in the practice period. To assess the anxiety of the participants, the state-trait anxiety inventory test was carried out before the pharmacy practice. Salivary α-amylase activity (sAA) was measured as a marker of sympathetic nervous system activity. In the placebo-group, sAA in the morning (pre-practice sAA) was higher than in theanine-group during the pharmacy practice (p=0.032). Subjective stress was significantly lower in the theanine-group than in the placebo-group (p=0.020). These results suggest that theanine intake had anti-stress effect on students. Furthermore, students with higher pre-practice sAA showed significantly higher trait anxiety in both groups (p=0.015). Similarly, higher pre-practice sAA was correlated to shorter sleeping time in both groups (p=0.41×10(-3)). Stressful condition increased the level of sAA that was essentially affected by individual trait anxiety. The low levels of pre-practice sAA and subjective stress in the theanine-group suggest that theanine intake suppressed initial stress response of students assigned for a long-term commitment of pharmacy practice. © 2013. Published by Elsevier Inc. All rights reserved.

  1. Impact of retrograde shear rate on brachial and superficial femoral artery flow-mediated dilation in older subjects.

    NARCIS (Netherlands)

    Schreuder, T.H.A.; Green, D.J.; Hopman, M.T.E.; Thijssen, D.H.

    2015-01-01

    An inverse, dose-dependent relationship between retrograde shear rate and brachial artery endothelial function exists in young subjects. This relationship has not been investigated in older adults, who have been related to lower endothelial function, higher resting retrograde shear rate and higher

  2. 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...

  3. 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 of accidents and injuries. Slide 5 ? CSIR 2010 www.csir.co.za Definitions Work place Stress ? Work place stress can be defined as the harmful physical and emotional responses that occur when the psychological and/or physiological....csir.co.za ? Slide 8 Salivary cortisol levels ? Biochemical characteristics of the human, in relation to environmental or personal stimuli, produce physiological responses and significant links with psychological stress have been shown ? Method...

  4. Antioxidant capacity of polyphenolic extracts from leaves of Crataegus laevigata and Crataegus monogyna (Hawthorn) subjected to drought and cold stress.

    Science.gov (United States)

    Kirakosyan, Ara; Seymour, Elisabeth; Kaufman, Peter B; Warber, Sara; Bolling, Steven; Chang, Soo Chul

    2003-07-02

    Crataegus laevigata and Crataegus monogyna (hawthorn) were subjected to drought and cold stress treatments, and polyphenolic extracts from control and stress-treated plants were assayed for antioxidant capacities using a modified version of the Total Antioxidant Status Assay (Randox, San Francisco, CA). In addition, these plants were analyzed for levels of flavanol-type substance [(-)-epicatechin] and flavonoid (vitexin 2' '-O-rhamnoside, acetylvitexin 2' '-O-rhamnoside, and hyperoside) constituents that are important metabolites in hawthorn herbal preparations used to treat patients with heart disease. Drought and cold stress treatments caused increases in levels of (-)-epicatechin and hyperoside in both Crataegus species. Such treatments also enhanced the antioxidant capacity of the extracts. The results from this study thus indicate that these kinds of stress treatments can enhance the levels of important secondary metabolites and their total antioxidant capacities in leaves of Crataegus.

  5. 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.

  6. Differential stress response in rats subjected to chronic mild stress is accompanied by changes in CRH-family gene expression at the pituitary level.

    Science.gov (United States)

    Kolasa, Magdalena; Faron-Górecka, Agata; Kuśmider, Maciej; Szafran-Pilch, Kinga; Solich, Joanna; Żurawek, Dariusz; Gruca, Piotr; Papp, Mariusz; Dziedzicka-Wasylewska, Marta

    2014-11-01

    The purpose of this study was to examine molecular markers of the stress response at the pituitary and peripheral levels in animals that responded differently to chronic mild stress (CMS). Rats were subjected to 2-weeks CMS and symptoms of anhedonia was measured by the consumption of 1% sucrose solution. mRNA levels of CRH-family neuropeptides (Crh-corticotropin-releasing hormone, Ucn1-urocortin 1, Ucn2-urocortin 2, Ucn3-urocortin 3), CRH receptors (Crhr1-corticotropin-releasing hormone receptor 1, Crhr2-corticotropin-releasing hormone receptor 2) and Crhbp (corticotropin-releasing factor binding protein) in the pituitaries of rats were determined with real-time PCR. Plasma levels of ACTH (adrenocorticotropin), CRH and urocortins were measured with ELISA assays. CMS procedure led to the development of anhedonia manifested by the decreased sucrose consumption (stress-reactive, SR, stress-susceptible group). Additionally, the group of animals not exhibiting any signs of anhedonia (stress non-reactive, SNR, stress-resilient group) and the group characterized by the increased sucrose consumption (stress invert-reactive group SIR) were selected. The significant increases in ACTH plasma level accompanied by the decreases in the pituitary gene expression of the Crh, Ucn2 and Ucn3 in both stress non-reactive and stress invert-reactive groups were observed. The only molecular change observed in stress-reactive group was the increase in UCN2 plasma level. The differentiated behavioral stress responses were reflected by gene expression changes in the pituitary. Alterations in the mRNA levels of Crh, Ucn2 and Ucn3 in the pituitary might confirm the paracrine and/or autocrine effects of these peptides in stress response. The opposite behavioral effect between SNR vs. SIR groups and the surprising similarity at gene expression and plasma ACTH levels in these two groups may suggest the discrepancy between molecular and behavioral stress responses; however, there results might

  7. 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.

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

    Science.gov (United States)

    Mibei, Elias K; Ambuko, Jane; Giovannoni, James J; Onyango, Arnold N; Owino, Willis O

    2017-01-01

    African eggplants (Solanum aethiopicum and S. macrocarpon) are among the most economically important and valuable vegetable and fruit crops. They are a major source of biologically active nutritional substances and metabolites which are essential for plant growth, development, stress adaptation and defense. Among these metabolites are the carotenoids which act as accessory pigments for photosynthesis and precursor to plant hormones. Though African eggplants are known to be resistant to various abiotic stresses, the effect of these stresses on secondary metabolites has not been well defined. The objective of this study was to establish the effect of drought stress on carotenoid profiles of nineteen African eggplant accessions selected based on leaf and fruit morphological traits. Stress was achieved by limiting irrigation and maintaining the wilting state of the crops. Fresh leaves were sampled at different maturity stages; before stress, 2 weeks and 4 weeks after stress for carotenoid analysis. The fresh harvested leaf tissues were immediately frozen in liquid nitrogen and ground. Analysis was carried out using a Dionex HPLC machine coupled to Photo Array Detector and Chromeleon software package (Thermo Fisher Scientific Inc, Waltham, Massachusetts, USA). Major carotenoids viz;. Xanthophylls (neoxanthin, violaxanthin, zeaxanthin and lutein) and carotenes (β-carotene and α-carotene), phytofluene, lycopene, phytoene as well as chlorophylls (chlorophyll-b and Chlorophyll-a) were targeted. The carotenoids increased with maturity stage of the crop. Although the stressed crops reported significantly decreased amount of carotenes, chlorophylls, neoxanthin and violaxanthin, the concentration of zeaxanthin increased with stress whereas lutein had no significant change. Chlorophyll-a was significantly high in all the control accessions. Two accessions reported significantly higher contents of carotenoids as compared to the other accessions. The results of this study

  10. Combined heart rate variability and dynamic measures for quantitatively characterizing the cardiac stress status during cycling exercise.

    Science.gov (United States)

    Chen, Szi-Wen; Liaw, Jiunn-Woei; Chang, Ya-Ju; Chuang, Li-Ling; Chien, Chun-Tse

    2015-08-01

    In this study, we aimed to seek for different ways of measuring cardiac stress in terms of heart rate variability (HRV) and heart rate (HR) dynamics, and to develop a novel index that can effectively summarize the information reflected by these measures to continuously and quantitatively characterize the cardiac stress status during physical exercise. Standard deviation, spectral measure of HRV as well as a nonlinear detrended fluctuation analysis (DFA) based fractal-like behavior measure of HR dynamics were all evaluated on the RR time series derived from windowed electrocardiogram (ECG) data for the subjects undergoing cycling exercise. We recruited eleven young healthy subjects in our tests. Each subject was asked to maintain a fixed speed under a constant load during the pedaling test. We obtained the running estimates of the standard deviation of the normal-to-normal interval (SDNN), the high-fidelity power spectral density (PSD) of HRV, and the DFA scaling exponent α, respectively. A trend analysis and a multivariate linear regression analysis of these measures were then performed. Numerical experimental results produced by our analyses showed that a decrease in both SDNN and α was seen during the cycling exercise, while there was no significant correlation between the standard lower frequency to higher frequency (LF-to-HF) spectral power ratio of HRV and the exercise intensity. In addition, while the SDNN and α were both negatively correlated with the Borg rating of perceived exertion (RPE) scale value, it seemed that the LF-to-HF power ratio might not have substantial impact on the Borg value, suggesting that the SDNN and α may be further used as features to detect the cardiac stress status during the physical exercise. We further approached this detection problem by applying a linear discriminant analysis (LDA) to both feature candidates for the task of cardiac stress stratification. As a result, a time-varying parameter, referred to as the cardiac

  11. 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.

  12. Anger responses to psychosocial stress predict heart rate and cortisol stress responses in men but not women.

    Science.gov (United States)

    Lupis, Sarah B; Lerman, Michelle; Wolf, Jutta M

    2014-11-01

    While previous research has suggested that anger and fear responses to stress are linked to distinct sympathetic nervous system (SNS) stress responses, little is known about how these emotions predict hypothalamus-pituitary-adrenal (HPA) axis reactivity. Further, earlier research primarily relied on retrospective self-report of emotion. The current study aimed at addressing both issues in male and female individuals by assessing the role of anger and fear in predicting heart rate and cortisol stress responses using both self-report and facial coding analysis to assess emotion responses. We exposed 32 healthy students (18 female; 19.6±1.7 yr) to an acute psychosocial stress paradigm (TSST) and measured heart rate and salivary cortisol levels throughout the protocol. Anger and fear before and after stress exposure was assessed by self-report, and video recordings of the TSST were assessed by a certified facial coder to determine emotion expression (FACS). Self-reported emotions and emotion expressions did not correlate (all p>.23). Increases in self-reported fear predicted blunted cortisol responses in men (β=0.41, p=.04). Also for men, longer durations of anger expression predicted exaggerated cortisol responses (β=0.67 p=.004), and more anger incidences predicted exaggerated cortisol and heart rate responses (β=0.51, p=.033; β=0.46, p=.066, resp.). Anger and fear did not predict SNS or HPA activity for females (all p>.23). The current differential self-report and facial coding findings support the use of multiple modes of emotion assessment. Particularly, FACS but not self-report revealed a robust anger-stress association that could have important downstream health effects for men. For women, future research may clarify the role of other emotions, such as self-conscious expressions of shame, for physiological stress responses. A better understanding of the emotion-stress link may contribute to behavioral interventions targeting health-promoting ways of

  13. 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...

  14. Behaviour of S 355JO steel subjected to uniaxial stress at lowered ...

    Indian Academy of Sciences (India)

    Administrator

    defined as the progressive accumulation of plastic strain in a specimen or machine part under stress, at elevated temperature over a period of time. Sometimes, it can be easy to quantify damage in laboratory creep procedure conducted at constant stress (load) and temperature, but components of machines in service hardly ...

  15. Recurrence rate and subjective symptoms after standardized (Hamburg protocol) phototherapeutic keratectomy on recurrent corneal erosions.

    Science.gov (United States)

    Mehlan, J; Steinberg, J; Traber, L; Katz, T; Linke, S J

    2016-10-01

    To evaluate the objective and subjective outcome after phototherapeutic keratectomy (PTK) on recurrent corneal erosions (Hamburg protocol). For the standardized PTK according to Hamburg protocol a manual abrasio corneae performed with 20 % alcohol is followed by an excimer ablation depth of ≥15 μm (group1 15 μm; group 2 > 15 μm ablation depth) and 7 mm optical zone. All patients (N = 48) were invited for follow-up examinations and the evaluation of changes concerning subjective symptoms. A significantly reduced subjective impairment of night vision, significantly less pain and less foreign body sensations (for all p Hamburg Schema) is a safe and effective procedure to reduce subjective symptoms and improve discomfort in recurrent corneal erosion.

  16. 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

  17. Analyses of layer-thickness effects in bilayered dental ceramics subjected to thermal stresses and ring-on-ring tests

    Energy Technology Data Exchange (ETDEWEB)

    Hsueh, Chun-Hway [ORNL; Thompson, G. A. [U.S. Army Dental and Trauma Research Detachment, Greak Lakes; Jadaan, Osama M. [University of Wisconsin, Platteville; Wereszczak, Andrew A [ORNL; Becher, Paul F [ORNL

    2008-01-01

    Objectives. The purpose of this study was to analyze the stress distribution through the thickness of bilayered dental ceramics subjected to both thermal stresses and ring-on-ring tests and to systematically examine how the individual layer thickness influences this stress distribution and the failure origin. Methods. Ring-on-ring tests were performed on In-Ceram Alumina/Vitadur Alpha porcelain bilayered disks with porcelain in the tensile side, and In-Ceram Alumina to porcelain layer thickness ratios of 1:2, 1:1, and 2:1 were used to characterize the failure origins as either surface or interface. Based on the thermomechanical properties and thickness of each layer, the cooling temperature from glass transition temperature, and the ring-on-ring loading configuration, the stress distribution through the thickness of the bilayer was calculated using closed-form solutions. Finite element analyses were also performed to verify the analytical results. Results. The calculated stress distributions showed that the location of maximum tension during testing shifted from the porcelain surface to the In-Ceram Alumina/porcelain interface when the relative layer thickness ratio changed from 1:2 to 1:1 and to 2:1. This trend is in agreement with the experimental observations of the failure origins. Significance. For bilayered dental ceramics subjected to ring-on-ring tests, the location of maximum tension can shift from the surface to the interface depending upon the layer thickness ratio. The closed-form solutions for bilayers subjected to both thermal stresses and ring-on-ring tests are explicitly formulated which allow the biaxial strength of the bilayer to be evaluated.

  18. 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.

  19. 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.

  20. Evaluation of primary water stress corrosion cracking growth rates by using the extended finite element method

    Directory of Open Access Journals (Sweden)

    Sung-Jun Lee

    2015-12-01

    Conclusion: Reliable CGR curves were obtained without complex environmental facilities or a high degree of experimental effort. The proposed method may be used to assess the PWSCC resistance of nuclear components subjected to high residual stresses such as those resulting from dissimilar metal welding parts.

  1. Dysarthria Associated with Traumatic Brain Injury: Speaking Rate and Emphatic Stress

    Science.gov (United States)

    Wang, Y.T.; Kent, R.D.; Duffy, J.R.; Thomas, J.E.

    2005-01-01

    Prosodic abnormality is common in the dysarthria associated with traumatic brain injury (TBI), and adjustments of speaking rate and emphatic stress are often used as steps in treating the speech disorder in patients with TBI-induced dysarthria. However, studies to date do not present a clear and detailed picture of how speaking rate and emphatic…

  2. 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...

  3. A Study on a Stress Reaction Measure Creation in University Student's : Subject were Daito Bunka University Student's

    OpenAIRE

    田中, 博史

    2003-01-01

    contents of data in a 144 item list. (Daily stress levels of Daito Bunka University students) Using a pre research test formula. Then we made a ore test of 522 students and collected the subjects data. We then preformed a factor analysis of the factor structures and examined all remaining factors and proceeded to the naming. 1) The Daito Bunka University stress diagnostic test that consists of 54 items of 6 factors (Factorl is 20 items, Factor2 is 12 items, FactorS is 8 items, Factor4 is 6 it...

  4. [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.

  5. Developmental differences in the effects of alcohol and stress on heart rate variability.

    Science.gov (United States)

    Saalfield, Jessica; Spear, Linda

    2014-08-01

    Adolescent rats differ in their responses to stress and ethanol from their adult counterparts, although not much is known about the contribution of the autonomic nervous system (ANS) to these differences. This study assessed the impact of stress, ethanol, and their combination on parameters of heart rate variability (HRV) in adolescent and adult male Sprague-Dawley rats. Animals were habituated to the testing box and neck sensors (MouseOX, STARR Life Sciences Corp.) used for recording heart rate (HR). After 8-10min of baseline recording, animals were restrained for 90min or returned home, followed by intraperitoneal injection of 0, 0.5, 1.0, or 1.5g/kg ethanol. The 8-10min test recording occurred 30min post-injection. Ethanol-related decreases in LF (an index of sympathetic activity) were evident under non-stressed conditions in adolescents but only after stress in adults, perhaps in part due to apparent ethanol-induced sympathetic deactivation in adolescents. Parasympathetic tone, indexed by HF, was unaffected by both ethanol and stress in adolescents, while again both the 1.0 and 1.5g/kg ethanol doses decreased HF in adults following stress. Ethanol also decreased low frequency/high frequency tone (LF/HF), an index of sympathovagal balance, only in adolescents, with no decrease evident in adults. Further, stressed adults, and not adolescents, had significantly lower CORT and PROG values than their non-stressed counterparts. Taken together, these results demonstrate notable age differences in the ANS response to ethanol under stressful vs. non-stressful circumstances, reflected by ethanol-mediated autonomic effects that were more pronounced following stressor exposure in adults but under non-stressed conditions in adolescents. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. 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.

  7. Regulation of some salt defense-related genes in relation to physiological and biochemical changes in three sugarcane genotypes subjected to salt stress.

    Science.gov (United States)

    Poonsawat, Wasinee; Theerawitaya, Cattarin; Suwan, Therapatt; Mongkolsiriwatana, Chareerat; Samphumphuang, Thapanee; Cha-um, Suriyan; Kirdmanee, Chalermpol

    2015-01-01

    Sugarcane (Saccharum officinale L.; Poaceae) is a sugar-producing plant widely grown in tropic. Being a glycophytic species, it is very sensitive to salt stress, and salinity severely reduces growth rate and cane yield. The studies investigating the regulation of salt defense metabolite-related genes in relation to final biochemical products in both susceptible and tolerant genotypes of sugarcane are largely lacking. We therefore investigated the expression levels of sugarcane shaggy-like kinase (SuSK), sucrose transporter (SUT), proline biosynthesis (pyrolline-5-carboxylate synthetase; P5CS), ion homeostasis (NHX1), and catalase (CAT2) mRNAs, and contents of Na(+), soluble sugar, and free proline in three sugarcane genotypes (A19 mutant, K88-92, and K92-80) when subjected to salt stress (200 mM NaCl). The relative expression levels of salt defense-related genes in salt-stressed plantlets of sugarcane cv. K88-92 were upregulated in relation to salt exposure times when compared with glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as housekeeping gene. In addition, final biochemical products, i.e., low Na(+), sucrose enrichment, and free proline accumulation, were evidently demonstrated in salt-stressed plantlets. Chlorophyll b, total chlorophyll, total carotenoid concentrations, and maximum quantum yield of PSII (F v/F m) in positive check (K88-92) were maintained under salt stress, leading to high net photosynthetic rate (P n) and growth retention (root length, fresh weight, and leaf area). In contrast, photosynthetic abilities in negative check, K92-80, and A19 mutant lines grown under salt stress declined significantly in comparison to control, leading to a reduction in P n and an inhibition of overall growth characters. The study concludes that the genetic background of sugarcane cv. K88-92 may further be exploited to play a key role as parental clone for sugarcane breeding program for salt-tolerant purposes.

  8. Outdoor dynamic subject-specific evaluation of internal stresses in the residual limb: hydraulic energy-stored prosthetic foot compared to conventional energy-stored prosthetic feet.

    Science.gov (United States)

    Portnoy, Sigal; Kristal, Anat; Gefen, Amit; Siev-Ner, Itzhak

    2012-01-01

    The prosthetic foot plays an important role in propelling, breaking, balancing and supporting body loads while the amputee ambulates on different grounds. It is therefore important to quantify the effect of the prosthetic foot mechanism on biomechanical parameters, in order to prevent pressure ulcers and deep tissue injury. Our aim was to monitor the internal stresses in the residuum of transtibial amputation (TTA) prosthetic-users ambulating on different terrains, which the amputees encounter during their daily activities, i.e. paved floor, grass, ascending and descending stairs and slope. We specifically aimed to compare between the internal stresses in the TTA residuum of amputees ambulating with a novel hydraulic prosthetic foot compared to conventional energy storage and return (ESR) prosthetic feet. Monitoring of internal stresses was accomplished using a portable subject-specific real-time internal stress monitor. We found significant decrease (phydraulic foot, compared to walking with ESR feet. The loading rate calculated while ambulating with the hydraulic foot was at least three times lower than the loading rate calculated while ambulating with the ESR foot. Although the average decrease in internal stresses was ≈ 2-fold larger when replacing single-toe ESR feet with the hydraulic foot than when replacing split-toed ESR feet with the hydraulic foot, the differences were statistically insignificant. Our findings suggest that using a hydraulic prosthetic foot may protect the distal tibial end of the TTA residuum from high stresses, therefore preventing pressure-related injury and pain. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Cognitive function, stress hormones, heart rate and nutritional status during simulated captivity in military survival training.

    Science.gov (United States)

    Lieberman, Harris R; Farina, Emily K; Caldwell, John; Williams, Kelly W; Thompson, Lauren A; Niro, Philip J; Grohmann, Kyle A; McClung, James P

    2016-10-15

    Stress influences numerous psychological and physiological processes, and its effects have practical implications in a variety of professions and real-world activities. However, few studies have concurrently assessed multiple behavioral, hormonal, nutritional and heart-rate responses of humans to acute, severe stress. This investigation simultaneously assessed cognitive, affective, hormonal, and heart-rate responses induced by an intensely stressful real-world environment designed to simulate wartime captivity. Sixty males were evaluated during and immediately following participation in U.S. Army Survival, Evasion, Resistance, and Escape (SERE) school, three weeks of intense but standardized training for Soldiers at risk of capture. Simulated captivity and intense mock interrogations degraded grammatical reasoning (pworking memory (pnutritional status and heart rate are simultaneously altered, and each of these subsequently recovers at different rates. Published by Elsevier Inc.

  10. From beat rate variability in induced pluripotent stem cell-derived pacemaker cells to heart rate variability in human subjects.

    Science.gov (United States)

    Ben-Ari, Meital; Schick, Revital; Barad, Lili; Novak, Atara; Ben-Ari, Erez; Lorber, Avraham; Itskovitz-Eldor, Joseph; Rosen, Michael R; Weissman, Amir; Binah, Ofer

    2014-10-01

    We previously reported that induced pluripotent stem cell-derived cardiomyocytes manifest beat rate variability (BRV) resembling heart rate variability (HRV) in the human sinoatrial node. We now hypothesized the BRV-HRV continuum originates in pacemaker cells. To investigate whether cellular BRV is a source of HRV dynamics, we hypothesized 3 levels of interaction among different cardiomyocyte entities: (1) single pacemaker cells, (2) networks of electrically coupled pacemaker cells, and (3) the in situ sinoatrial node. We measured BRV/HRV properties in single pacemaker cells, induced pluripotent stem cell-derived contracting embryoid bodies (EBs), and electrocardiograms from the same individual. Pronounced BRV/HRV was present at all 3 levels. The coefficient of variance of interbeat intervals and Poincaré plot indices SD1 and SD2 for single cells were 20 times greater than those for EBs (P heart (the latter two were similar; P > .05). We also compared BRV magnitude among single cells, small EBs (~5-10 cells), and larger EBs (>10 cells): BRV indices progressively increased with the decrease in the cell number (P heart rhythm. The decreased BRV magnitude in transitioning from the single cell to the EB suggests that the HRV of in situ hearts originates from the summation and integration of multiple cell-based oscillators. Hence, complex interactions among multiple pacemaker cells and intracellular Ca(2+) handling determine HRV in humans and cardiomyocyte networks. Copyright © 2014 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  11. Single-subject research design: recommendations for levels of evidence and quality rating.

    Science.gov (United States)

    Romeiser Logan, Lynne; Hickman, Robbin R; Harris, Susan R; Heriza, Carolyn B

    2008-02-01

    The aim of this article is to present a set of evidence levels, accompanied by 14 quality or rigor questions, to foster a critical review of published single-subject research articles. In developing these guidelines, we reviewed levels of evidence and quality/rigor criteria that are in wide use for group research designs, e.g. randomized controlled trials, such as those developed by the Treatment Outcomes Committee of the American Academy for Cerebral Palsy and Developmental Medicine. We also reviewed methodological articles on how to conduct and critically evaluate single-subject research designs (SSRDs). We then subjected the quality questions to interrater agreement testing and refined them until acceptable agreement was reached. We recommend that these guidelines be implemented by clinical researchers who plan to conduct single-subject research or who incorporate SSRD studies into systematic reviews, and by clinicians who aim to practise evidence-based medicine and who wish to critically review pediatric single-subject research.

  12. Loss of pH control in Plasmodium falciparum parasites subjected to oxidative stress.

    Directory of Open Access Journals (Sweden)

    Donelly A van Schalkwyk

    Full Text Available The intraerythrocytic malaria parasite is susceptible to oxidative stress and this may play a role in the mechanism of action of some antimalarial agents. Here we show that exposure of the intraerythrocytic malaria parasite to the oxidising agent hydrogen peroxide results in a fall in the intracellular ATP level and inhibition of the parasite's V-type H(+-ATPase, causing a loss of pH control in both the parasite cytosol and the internal digestive vacuole. In contrast to the V-type H(+-ATPase, the parasite's digestive vacuole H(+-pyrophosphatase is insensitive to hydrogen peroxide-induced oxidative stress. This work provides insights into the effects of oxidative stress on the intraerythrocytic parasite, as well as providing an alternative possible explanation for a previous report that light-induced oxidative stress causes selective lysis of the parasite's digestive vacuole.

  13. Effects of far infrared rays irradiated from ceramic material (BIOCERAMIC) on psychological stress-conditioned elevated heart rate, blood pressure, and oxidative stress-suppressed cardiac contractility.

    Science.gov (United States)

    Leung, Ting-Kai; Chen, Chien-Ho; Tsai, Shih-Ying; Hsiao, George; Lee, Chi-Ming

    2012-10-31

    The present study examined the effects of BIOCERAMIC on psychological stress-conditioned elevated heart rate, blood pressure and oxidative stress-suppressed cardiac contractility using in vivo and in vitro animal models. We investigated the effects of BIOCERAMIC on the in vivo cardiovascular hemodynamic parameters of rats by monitoring their heart rates, systolic blood pressure, mean blood pressure and diastolic blood pressure. Thereafter, we assayed its effects on the heart rate in an isolated frog heart with and without adrenaline stimulation, and on cardiac contractility under oxidative stress. BIOCERAMIC caused significant decreases in heart rates and systolic and mean blood pressure in the stress-conditioned heart rate rat models (P frog heart with and without adrenaline stimulation (P < 0.05), and normalized cardiac contractility under oxidative stress (P < 0.05). BIOCERAMIC may, therefore, normalize the effects of psychological stress and oxidative stress conditions.

  14. High Prevalence of Stress and Low Prevalence of Alzheimer Disease CSF Biomarkers in a Clinical Sample with Subjective Cognitive Impairment.

    Science.gov (United States)

    Eckerström, Marie; Berg, Anne Ingeborg; Nordlund, Arto; Rolstad, Sindre; Sacuiu, Simona; Wallin, Anders

    2016-01-01

    Subjective cognitive impairment (SCI) is a trigger for seeking health care in a possible preclinical phase of Alzheimer's disease (AD), although the characteristics of SCI need clarification. We investigated the prevalence of psychosocial stress, depressive symptoms and CSF AD biomarkers in SCI and MCI (mild cognitive impairment). Memory clinic patients (SCI: n = 90; age: 59.8 ± 7.6 years; MCI: n = 160; age: 63.7 ± 7.0 years) included in the Gothenburg MCI study were examined at baseline. Variables were analyzed using logistic regression with SCI as dependent variable. Stress was more prevalent in SCI (51.1%) than MCI (23.1%); p patients had more previous depressive symptoms (p = 0.006), but showed no difference compared to MCI patients considering current depressive symptoms. A positive CSF AD profile was present in 14.4% of SCI patients and 35.0% of MCI patients (p = 0.001). Stress (p = 0.002), previous stress/depressive symptoms (p = 0.006) and a negative CSF AD profile (p = 0.036) predicted allocation to the SCI group. Psychosocial stress is more prevalent in SCI than previously acknowledged. The high prevalence and long-term occurrence of stress/depressive symptoms in SCI in combination with a low prevalence of altered CSF AD biomarkers strengthens the notion that AD is not the most likely etiology of SCI. © 2016 S. Karger AG, Basel.

  15. 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

    2017-09-01

    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 genes were found to be differentially expressed on days 1, 2, and 3 out of which 343, 261 and 256 genes were upregulated and 159, 133, and 120 genes were downregulated. Only 356 genes out of these were expressed on all 3 days, and only they were considered as significantly differentially expressed. KEGG pathway analysis revealed that ten pathways were significantly enriched; the top two among them were protein processing in endoplasmic reticulum and MAPK signaling pathways. These results suggest that thermal stress triggered a complex response in Holstein calves and the animals adjusted their 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.

  16. 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 protein processing in endoplasmic reticulum and MAPK signaling pathways. These results suggest that thermal stress triggered a complex response in Holstein calves and the animals adjusted their 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.

  17. Stress Analysis of Adhesive Lap Joint of Hollow Shafts Subjected to Torsional Moments

    OpenAIRE

    仲野, 雄一; 高城, 有希久

    2001-01-01

    The stress and strain distributions in adhesively bonded lap joints of dissimilar hollow shafts are examined using the axisymmetric theory of elasticity. In the analysis, the joint is modeled as an elastic three-body contact problem where the hollow shafts and the adhesive are replaced by finite hollow cylinders. The effects of the ratio of Young's modulus of the adhesive to that of the shaft, the overlap length and the thickness of the adhesive on the stress distributions at the interfaces i...

  18. 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 (...

  19. Stresses and Strains in Plain and Coldworked Annuli Subjected to Remote, Interference or Combined Loading

    Science.gov (United States)

    1992-05-01

    Australian Airlines, Library Qantas Airways Limited Civil Aviation Authority Hawker de Havilland Aust Pty Ltd, Victoria, Library Hawker de Havilland Aust Pty...of the annulus from the pin, (34): yielding of the resulting open hole annulus (13) provides the positive stress limit of elastic behaviour shown...curves in Figs. 11 and 12. It is seen that, under either tensile or compressive loading, the stress limits are identical in the region from the bore to the

  20. 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......-room and three combined-room measurements, it was found that the traditional measure of speech, such as the speech transmission index, was not correlated with the subjective classifications. Thus, a correlation analysis was conducted as an attempt to find the hidden factors behind the subjective perceptions...

  1. Two separable mechanisms are responsible for mental stress effects on high frequency heart rate variability: an intra-individual approach in a healthy and a diabetic sample.

    Science.gov (United States)

    Kuehl, Linn K; Deuter, Christian E; Richter, Steffen; Schulz, André; Rüddel, Heinz; Schächinger, Hartmut

    2015-03-01

    Central withdrawal of parasympathetic cardiac control and increased respiratory frequency represent two important determinants of reduced respiratory-related heart rate variability (HRV). However, studies are missing to disentangle their relative contribution during mental stress. Healthy subjects (n=10) and type 2 diabetic patients (n=8), the latter with evidence of cardiac autonomic neuropathy, participated in this study. Using an intra-individual approach, high-frequency (hf) HRV was assessed for spontaneous (during rest and mental stress) and paced breathing (0.15, 0.2, 0.25, 0.3, 0.35, 0.4 and 0.45 Hz; randomized sequence). Mental stress was induced by a challenging reaction time task. Effects of respiratory frequency on hf HRV were individually predicted by paced breathing data. Mental stress decreased hf HRV (phealthy subjects and in patients with evidence of diabetic cardiac autonomic neuropathy. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. 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...

  3. Optimal protruding node length of bicycle seats determined using cycling postures and subjective ratings.

    Science.gov (United States)

    Chen, Yi-Lang; Liu, Yi-Nan

    2014-07-01

    This study examined body posture, subjective discomfort, and stability, requiring the participants to ride a stationary bicycle for 20 min (cadence: 60 rpm; workrate: 120 W), using various combinations of two handle heights and five seat-protruding node lengths (PNLs). The results indicated that bicycle handle height significantly influenced body posture, and that seat PNL caused differences in the riders' subjective discomfort and stability scores. The various PNLs affected only the trunk angle (approximately 6°), but had significantly positive (r = 0.994, p bicycle seat designs. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  4. Cyclic stretch-induced stress fiber dynamics - Dependence on strain rate, Rho-kinase and MLCK

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chin-Fu; Haase, Candice [Department of Biomedical Engineering, Texas A and M University, College Station (United States); Deguchi, Shinji [Department of Biomedical Engineering, Tohoku University (Japan); Kaunas, Roland, E-mail: rkaunas@tamu.edu [Department of Biomedical Engineering, Texas A and M University, College Station (United States)

    2010-10-22

    Research highlights: {yields} Cyclic stretch induces stress fiber disassembly, reassembly and fusion perpendicular to the direction of stretch. {yields} Stress fiber disassembly and reorientation were not induced at low stretch frequency. {yields} Stretch caused actin fiber formation parallel to stretch in distinct locations in cells treated with Rho-kinase and MLCK inhibitors. -- Abstract: Stress fiber realignment is an important adaptive response to cyclic stretch for nonmuscle cells, but the mechanism by which such reorganization occurs is not known. By analyzing stress fiber dynamics using live cell microscopy, we revealed that stress fiber reorientation perpendicular to the direction of cyclic uniaxial stretching at 1 Hz did not involve disassembly of the stress fiber distal ends located at focal adhesion sites. Instead, these distal ends were often used to assemble new stress fibers oriented progressively further away from the direction of stretch. Stress fiber disassembly and reorientation were not induced when the frequency of stretch was decreased to 0.01 Hz, however. Treatment with the Rho-kinase inhibitor (Y27632) reduced stress fibers to thin fibers located in the cell periphery which bundled together to form thick fibers oriented parallel to the direction of stretching at 1 Hz. In contrast, these thin fibers remained diffuse in cells subjected to stretch at 0.01 Hz. Cyclic stretch at 1 Hz also induced actin fiber formation parallel to the direction of stretch in cells treated with the myosin light chain kinase (MLCK) inhibitor ML-7, but these fibers were located centrally rather than peripherally. These results shed new light on the mechanism by which stress fibers reorient in response to cyclic stretch in different regions of the actin cytoskeleton.

  5. Influence of Dissimilar Adherends on the Stress Distribution in Adhesively Bonded Composite Joints Subjected to Impact Loadings

    Science.gov (United States)

    Hazimeh, R.; Challita, G.; Khalil, K.; Othman, R.

    2015-01-01

    The influence of nonsymmetric rotation of laminates on the shear and peel stresses in the adhesive layer of adhesively bonded double-lap composite joints (DLJ) subjected to in-plane impact compressive loadings is investigated by using a three-dimensional finite-element analysis. The compressive in-plane impact on DLJ is simulated using the direct Hopkinson bar system, and the specimen is impacted by an incident bar. It is found that the rotation of any adherend from the 0° orientation leads to a decrease in the average shear stress in the adhesive layer, but the maximum peel stress is affected only by the longitudinal stiffness of the outer adherend and decreases when this stiffness diminishes.

  6. Plasma hormone levels in human subject during stress loads in microgravity and at readaptation to Earth's gravity.

    Science.gov (United States)

    Macho, L; Koska, J; Ksinantova, L; Vigas, M; Noskov, V B; Grigoriev, A I; Kvetnansky, R

    2001-07-01

    In great part of the investigations of endocrine system functions in astronauts during space flights the plasma levels of hormones and metabolites were determined only in resting conditions, usually from one blood sample collection. Such levels reflected the psychical and physical state and new hormonal homeostasis of organism at the time of blood collection, however, the functional capacity of neuroendocrine system to respond to various stress stimuli during space flight remained unknown. The aim of present investigations was to study dynamic changes of hormone levels during the stress and metabolic loads (insulin induced hypoglycemia, physical exercise and oral glucose tolerance test) at the exposure of human subject to microgravity on the space station MIR. The responses of sympatico-adrenomedullary system to these stress and workloads were presented by Kvetnansky et al.

  7. Stability Control of Underground Roadways Subjected to Stresses Caused by Extraction of a 10-m-Thick Coal Seam: A Case Study

    Science.gov (United States)

    Chen, Yong; Ma, Shuqi; Yu, Yang

    2017-09-01

    Extraction of a 10-m-thick coal seam in one single lift using the longwall top coal caving method caused severe deformations in underground roadways in Majialiang coal mine in Shanxi Province, China. Field monitoring of stress changes in the roof and in the coal pillar, and deformation of the 14202 tailgate, were carried out. The deformation monitoring found that the maximum floor heave of the 14202 tailgate was 1.85 m when the monitoring point was 250 m behind the longwall working face, while the maximum roof subsidence and the maximum rib-rib convergence was 0.93 and 1.14 m, respectively. The deformation rate of the 14202 tailgate increased dramatically when the monitoring point was at distances of 100-150 m behind the longwall working face, which reflected the fact that the tailgate underwent sharply increased loads within this range. Field monitoring of stress changes and the displacement of the 14202 tailgate revealed that the impact range of the mining-induced stresses in longitudinal direction (the same as the mining direction) was from 60 m ahead of the longwall face to 250 m behind the longwall face. Additionally, the mining impact range in transverse direction was more than 45 m, indicating that the coal pillar width should be larger than 45 m to avoid significant influences of mining-induced stresses. This finding was applied to the 14103 tailgate, which was subjected to similar mining and geological conditions as the 14202 tailgate. A coal pillar with width of 56 m was adopted in the 14103 tailgate, and displacement monitoring showed that large deformation was successfully controlled. The field investigations in this study provide a basis for design of a proper coal pillar width of underground roadways when subjected to large stresses induced by mining of thick coal seams in a single lift.

  8. The spatial preference map of Dutch entrepreneurs : Subjective rating of locations, 1983, 1993 and 2003

    NARCIS (Netherlands)

    Meester, Wilhelm J.; Pellenbarg, Pieter H.

    2006-01-01

    Location decisions are often based on inaccurate information about potential locations. Decision-makers seem to be guided by their subjective interpretation of reality, not so much by reality itself. Twenty years ago this fundamental idea was the starting point for a research programme of the

  9. 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...

  10. 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..., railway line or oil or gas pipeline where published tariff rates are in effect”. In order for this... is actually governed by published tariff rates in effect pursuant to State or Federal law for such...

  11. Effects of alprazolam and clonidine on carbon dioxide-induced increases in anxiety rating in healthy human subjects

    Energy Technology Data Exchange (ETDEWEB)

    Woods, S.W.; Krystal, J.H.; Heninger, G.R.; Charney, D.S.

    1989-01-01

    In order to investigate possible neurobiologic mechanisms underlying carbon dioxide-induced anxiety, the effects of oral alprazolam 0.75 mg and intravenous clonidine 2 mcg/kg on CO/sub 2/-induced increases in ratings of subjective anxiety, pulse rate, and ventilation were measured in healthy human subjects. Pretreatment with alprazolam but not with clonidine significantly reduced the CO/sub 2/-induced increases in ratings of anxiety. Neither drug altered CO/sub 2/-induced increases in pulse rate or ventilatory responses. Clonidine did produce potent sedative and hypotensive effects. The behavioral data suggest that the mechanisms through which CO/sub 2/ induces anxiety-like effects involve neural systems regulated by benzodiazepine receptors and, secondly, that they appear not to require normal functioning of noradrenergic systems. Carbon dioxide may provide a useful model system for identification of new drugs with anxiolytic properties.

  12. 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

    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...... 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....

  13. Miotic and subject-rated effects of therapeutic doses of tapentadol, tramadol, and hydromorphone in occasional opioid users.

    Science.gov (United States)

    Stoops, William W; Glaser, Paul E A; Rush, Craig R

    2013-07-01

    Tapentadol is a novel analgesic that activates mu-opioid receptors and blocks norepinephrine reuptake. There is very little information available regarding the non-analgesic pharmacodynamic effects of tapentadol. This outpatient study evaluated the physiological, subject-rated, and performance effects of therapeutic doses of tapentadol compared to two control drugs in humans. This double-blind, within-subject study examined the effects of oral placebo, tapentadol (25, 50, and 75 mg), tramadol (50, 100, and 150 mg), and hydromorphone (2, 4, and 6 mg). Nine occasional opioid users completed the study. Pharmacodynamic drug effects were measured before and for 6 h after drug administration. All three doses of the tested drugs produced comparable, time-dependent decreases in pupil diameter, but the effects were generally not dose dependent. The high dose of tapentadol, as well as all three doses of tramadol and hydromorphone, increased positive subject-rated effects (e.g., "Good Effects" and "Like the Drug") as a function of time. Only tramadol increased negative subject-rated effects (e.g., "Bad Effects" and "Nauseous"); however, these were of low magnitude. The highest tested dose of tapentadol produced a profile of positive effects comparable to that of hydromorphone, whereas tramadol produced positive and negative subject-rated effects. The mixed findings for tramadol are consistent with previous findings indicating that it has a distinct profile of effects relative to prototypic opioids. Future research should examine the effects of higher tapentadol doses, as well as the factors contributing to the different subject-rated profile of effects observed for tramadol relative to tapentadol and hydromorphone.

  14. 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.

  15. 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.

  16. Behaviour and modelling of aluminium alloy AA6060 subjected to a wide range of strain rates and temperatures

    Directory of Open Access Journals (Sweden)

    Vilamosa Vincent

    2015-01-01

    Full Text Available The thermo-mechanical behaviour in tension of an as-cast and homogenized AA6060 alloy was investigated at a wide range of strains (the entire deformation process up to fracture, strain rates (0.01–750 s−1 and temperatures (20–350 ∘C. The tests at strain rates up to 1 s−1 were performed in a universal testing machine, while a split-Hopkinson tension bar (SHTB system was used for strain rates from 350 to 750 s−1. The samples were heated with an induction-based heating system. A typical feature of aluminium alloys at high temperatures is that necking occurs at a rather early stage of the deformation process. In order to determine the true stress-strain curve also after the onset of necking, all tests were instrumented with a digital camera. The experimental tests reveal that the AA6060 material has negligible strain-rate sensitivity (SRS for temperatures lower than 200 ∘C, while both yielding and work hardening exhibit a strong positive SRS at higher temperatures. The coupled strain-rate and temperature sensitivity is challenging to capture with most existing constitutive models. The paper presents an outline of a new semi-physical model that expresses the flow stress in terms of plastic strain, plastic strain rate and temperature. The parameters of the model were determined from the tests, and the stress-strain curves from the tests were compared with the predictions of the model. Good agreement was obtained over the entire strain rate and temperature range.

  17. Unsaturated Oral Fat Load Test Improves Glycemia, Insulinemia and Oxidative Stress Status in Nondiabetic Subjects with Abdominal Obesity.

    Science.gov (United States)

    Martinez-Hervas, Sergio; Navarro, Inmaculada; Real, Jose T; Artero, Ana; Peiro, Marta; Gonzalez-Navarro, Herminia; Carmena, Rafael; Ascaso, Juan F

    2016-01-01

    To evaluate the changes in glycemia, insulinemia, and oxidative stress markers during an oral fat load test in nondiabetic subjects with abdominal obesity and to analyze the association between postprandial oxidative stress markers and postprandial glucose and insulin responses. We included 20 subjects with abdominal obesity (waist circumference > 102 cm for men and > 88 cm for women) and 20 healthy lean controls (waist circumference < 102 cm for men and < 88 cm for women). After 12 hours of fasting we performed a standardized fat load test (0-8 hours) with supracal® (50 g/m2). We determined metabolic parameters, oxidized and reduced glutathione, and malondialdehyde. In both groups, insulin, HOMA, oxidized/reduced glutathione ratio, and malondialdehyde significantly decreased in the postprandial state after the OFLT. All these parameters were significantly higher in the abdominal obesity group at baseline and during all the postprandial points, but the reduction from the baseline levels was significantly higher in the abdominal obesity group. Unsaturated fat improves insulin resistance and oxidative stress status. It is possible that a consumption of unsaturated fat could be beneficial even in subjects with abdominal obesity in postprandial state.

  18. Unsaturated Oral Fat Load Test Improves Glycemia, Insulinemia and Oxidative Stress Status in Nondiabetic Subjects with Abdominal Obesity.

    Directory of Open Access Journals (Sweden)

    Sergio Martinez-Hervas

    Full Text Available To evaluate the changes in glycemia, insulinemia, and oxidative stress markers during an oral fat load test in nondiabetic subjects with abdominal obesity and to analyze the association between postprandial oxidative stress markers and postprandial glucose and insulin responses.We included 20 subjects with abdominal obesity (waist circumference > 102 cm for men and > 88 cm for women and 20 healthy lean controls (waist circumference < 102 cm for men and < 88 cm for women. After 12 hours of fasting we performed a standardized fat load test (0-8 hours with supracal® (50 g/m2. We determined metabolic parameters, oxidized and reduced glutathione, and malondialdehyde.In both groups, insulin, HOMA, oxidized/reduced glutathione ratio, and malondialdehyde significantly decreased in the postprandial state after the OFLT. All these parameters were significantly higher in the abdominal obesity group at baseline and during all the postprandial points, but the reduction from the baseline levels was significantly higher in the abdominal obesity group.Unsaturated fat improves insulin resistance and oxidative stress status. It is possible that a consumption of unsaturated fat could be beneficial even in subjects with abdominal obesity in postprandial state.

  19. Effects of stress and relaxation on pain perception in subjects with pain-free occlusional disharmony compared with healthy controls.

    Science.gov (United States)

    Ruscheweyh, R; Becker, T; Born, Y; Çolak-Ekici, R; Marziniak, M; Evers, S; Gerlach, A L; Wolowski, A

    2015-04-01

    The significance of occlusal disharmony for the development of painful temporomandibular disorder (TMD) is controversial. The ongoing biomechanical strain caused by occlusal disharmony might lead to sensitization processes in the nociceptive system. Understanding these processes might be an important step toward understanding the possible relationship between occlusal disharmony and TMD. In this study, we therefore investigated whether subjects with occlusal disharmony (n = 22) differ from healthy controls (n = 26) in their pain perception and pain modulation by stress and relaxation. Trigeminal and extratrigeminal experimental pain perception (pinprick, heat, and pressure pain) was assessed before and after stress (mental arithmetic) and relaxation (viewing of low-arousal pictures). There were no group differences in pain perception at baseline or during the stress task. Compared with controls, the occlusal disharmony group exhibited an inadequate reduction in pain perception during relaxation, which was significant for the extratrigeminal site (P < 0.01) and reached a trend for significance at the trigeminal site (P = 0.1). These results suggest that subjects with occlusal disharmony show signs of disturbed endogenous pain inhibition during relaxation. There is evidence for the presence of sensitization of the nociceptive system in subjects with occlusal disharmony. Possibly, deficient inhibition of extratrigeminal and trigeminal pain perception by relaxation might contribute to the development of TMD or other chronic pain disorders. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. 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.

  1. Evidence from the AD 2000 Izu islands earthquake swarm that stressing rate governs seismicity

    Science.gov (United States)

    Toda, Shinji; Stein, Ross S.; Sagiya, Takeshi

    2002-09-01

    Magma intrusions and eruptions commonly produce abrupt changes in seismicity far from magma conduits that cannot be associated with the diffusion of pore fluids or heat. Such `swarm' seismicity also migrates with time, and often exhibits a `dog-bone'-shaped distribution. The largest earthquakes in swarms produce aftershocks that obey an Omori-type (exponential) temporal decay, but the duration of the aftershock sequences is drastically reduced, relative to normal earthquake activity. Here we use one of the most energetic swarms ever recorded to study the dependence of these properties on the stress imparted by a magma intrusion. A 1,000-fold increase in seismicity rate and a 1,000-fold decrease in aftershock duration occurred during the two-month-long dyke intrusion. We find that the seismicity rate is proportional to the calculated stressing rate, and that the duration of aftershock sequences is inversely proportional to the stressing rate. This behaviour is in accord with a laboratory-based rate/state constitutive law, suggesting an explanation for the occurrence of earthquake swarms. Any sustained increase in stressing rate-whether due to an intrusion, extrusion or creep event-should produce such seismological behaviour.

  2. 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.

  3. Self-reported and behavioral sound avoidance in tinnitus and hyperacusis subjects, and association with anxiety ratings.

    Science.gov (United States)

    Blaesing, Lena; Kroener-Herwig, Birgit

    2012-08-01

    The purpose of the study was to analyse the role of sound avoidance and anxiety in tinnitus subjects with hyperacusis, defined as hypersensitivity to low to moderate intensity sounds. A group of tinnitus subjects with hyperacusis was compared to tinnitus subjects without hyperacusis, and healthy controls. For assessing noise avoidance, a questionnaire was developed (noise avoidance questionnaire, NAQ) and the duration of self-exposure to a pure tone was assessed as a behavioral index. Different self-rating instruments concerning tinnitus (STI, TF-12), hyperacusis (GÜF), and anxiety (BAI, STAI-T) were used, as well as a psychoacoustic indicator of hyperacusis (ULL). Fifty-six tinnitus subjects with/without hyperacusis and 30 controls without tinnitus and hyperacusis participated in the experiment. The findings indicate that subjects with hyperacusis reported significantly more noise-related avoidance in daily life and show significantly shorter exposure to a pure tone than non-hyperacusic subjects, while discomfort was at the same level for each individual. Self-reported avoidance behavior correlated significantly with distress attributed to hyperacusis (r =0.81), and with anxiety ratings. These results suggest that hyperacusis is associated with noise-related avoidance behavior and anxiety. Systematic exposure to sound could play a significant role in the treatment of hyperacusis.

  4. 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

    In order to satisfy the growing need in high quality aluminum cast parts of the automobile industries, in the last decades the foundries have been showing an increasing interest in the implementation of numerical simulations as part of their process design. As a consequence, it is possible to find...... in literature several programs capable of simulating the entire casting process, i.e. filling, solidification, as well as developed thermomechanical stresses. However, it is common practice in the foundry industry that the results obtained by the simulation of the cast process are "forgotten" during...... the residual stresses are negligible. Nevertheless, in order to account for eventually "forgotten" thermal stresses, the automobile parts are usually over-designed. It is the objective of this work, that is part of the IDEAL (Integrated Development Routes for Optimized Cast Aluminium Components) project...

  5. 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.

  6. 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 × 10 9 asymmetric synapses, 1.06 × 10 8 symmetric synapses and 1.00 × 10 8 myelinated axons. The density of asymmetric synapses was 5.5/μm 3 and the density of symmetric synapses was 0.5/μm 3 . 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

  7. 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

  8. Self-compassion training modulates alpha-amylase, heart rate variability, and subjective responses to social evaluative threat in women.

    Science.gov (United States)

    Arch, Joanna J; Brown, Kirk Warren; Dean, Derek J; Landy, Lauren N; Brown, Kimberley D; Laudenslager, Mark L

    2014-04-01

    A growing body of research has revealed that social evaluative stressors trigger biological and psychological responses that in chronic forms have been linked to aging and disease. Recent research suggests that self-compassion may protect the self from typical defensive responses to evaluation. We investigated whether brief training in self-compassion moderated biopsychological responses to the Trier Social Stress Test (TSST) in women. Compared to attention (placebo) and no-training control conditions, brief self-compassion training diminished sympathetic (salivary alpha-amylase), cardiac parasympathetic, and subjective anxiety responses, though not HPA-axis (salivary cortisol) responses to the TSST. Self-compassion training also led to greater self-compassion under threat relative to the control groups. In that social stress pervades modern life, self-compassion represents a promising approach to diminishing its potentially negative psychological and biological effects. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Human birth weight patterns as an indicator of populations subject to environmental stress

    Energy Technology Data Exchange (ETDEWEB)

    Curtiss, J.R.B.; Ginevan, M.E.; Brown, C.D.

    1981-01-01

    The present study was undertaken to address two questions of central importance to the possibility of using birth weight as a monitor of the health status of populations. First, can one discern consistent effects of known influencing factors while controlling for only a small number of other influencing factors. This is important because standard birth certificates provide only a few variables in addition to weight. If known effects are obscured by noise from unknown sources, the effects of environmental stress may likewise be obscured. Second, if known effects are discernable, do known stressed populations show predictable patterns of depressed birth weight.

  10. 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.

  11. 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…

  12. 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...... 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...

  13. Frame rate vs resolution: A subjective evaluation of spatiotemporal perceived quality under varying computational budgets

    OpenAIRE

    Debattista, K.; Bugeja, K.; Spina, S.; Bashford-Rogers, T.; V. Hulusic

    2017-01-01

    Maximising performance for rendered content requires making compromises on quality parameters depending on the computational resources available. Yet, it is currently unclear which parameters best maximise perceived quality. This work investigates perceived quality across computational budgets for the primary spatio-temporal parameters of resolution and frame rate. Three experiments are conducted. Experiment 1 (n = 26) shows that participants prefer fixed frame rates of 60 frames per second (...

  14. Frame rate vs resolution : a subjective evaluation of spatiotemporal perceived quality under varying computational budgets

    OpenAIRE

    Debattista, Kurt; Bugeja, Keith; Spina, Sandro; Bashford-Rogers, Thomas; Hulusić, Vedad

    2017-01-01

    Maximizing performance for rendered content requires making compromises on quality parameters depending on the computational resources available . Yet, it is currently unclear which parameters best maximize perceived quality. This work investigates perceived quality across computational budgets for the primary spatiotemporal parameters of resolution and frame rate. Three experiments are conducted. Experiment 1 (n = 26) shows that participants prefer fixed frame rates of 60 frames per second (...

  15. 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.

  16. The rate dependence of the saturation flow stress of Cu and 1100 Al

    Energy Technology Data Exchange (ETDEWEB)

    Preston, D.L.; Tonks, D.L.; Wallace, D.C.

    1991-01-01

    The strain-rate dependence of the saturation flow stress of OFHC Cu and 1100 Al from 10{sup {minus}3}s{sup {minus}1} to nearly to 10{sup 12}s{sup {minus}1} is examined. The flow stress above 10{sup 9}s{sup {minus}1} is estimated using Wallace's theory of overdriven shocks in metals. A transition to the power-law behavior {Psi} {approximately} {tau}{sub s}{sup 5} occurs at a strain rate of order 10{sup 5}s{sup {minus}1}. 10 refs., 2 figs.

  17. Incorporation of Mean Stress Effects into the Micromechanical Analysis of the High Strain Rate Response of Polymer Matrix Composites

    Science.gov (United States)

    Goldberg, Robert K.; Roberts, Gary D.; Gilat, Amos

    2002-01-01

    The results presented here are part of an ongoing research program, to develop strain rate dependent deformation and failure models for the analysis of polymer matrix composites subject to high strain rate impact loads. A micromechanics approach is employed in this work, in which state variable constitutive equations originally developed for metals have been modified to model the deformation of the polymer matrix, and a strength of materials based micromechanics method is used to predict the effective response of the composite. In the analysis of the inelastic deformation of the polymer matrix, the definitions of the effective stress and effective inelastic strain have been modified in order to account for the effect of hydrostatic stresses, which are significant in polymers. Two representative polymers, a toughened epoxy and a brittle epoxy, are characterized through the use of data from tensile and shear tests across a variety of strain rates. Results computed by using the developed constitutive equations correlate well with data generated via experiments. The procedure used to incorporate the constitutive equations within a micromechanics method is presented, and sample calculations of the deformation response of a composite for various fiber orientations and strain rates are discussed.

  18. Effects of l-arginine and creatine administration on spatial memory in rats subjected to a chronic variable stress model.

    Science.gov (United States)

    dos Santos, Fabio Seidel; da Silva, Luiz Augusto; Pochapski, José Augusto; Raczenski, Alan; da Silva, Weber Claudio; Grassiolli, Sabrina; Malfatti, Carlos Ricardo Maneck

    2014-08-01

    Chronic stress results from repeated exposure to one or more types of stressors over a period, ranging from days to months, and can be associated with physical, behavioral, and neuropsychiatric manifestations. Some physiological alterations resulting from chronic stress can potentially cause deficits on spatial learning and memory. This study investigated the effects of chronic variable stress (CVS) and administration of l-arginine and creatine on spatial memory in rats. Furthermore, body, heart, adrenal weight, and plasma glucose and corticosterone levels were analyzed. Male Wistar rats were subjected to a CVS model for 40 days and evaluated for spatial memory after the stress period. Chronically stressed animals were treated daily by gavage with: 0.5% carboxymethylcellulose (Group Cs), 500 mg/kg l-arginine (Group Cs/La), 300 mg/kg creatine (Group Cs/Cr); and 500 mg/kg l-arginine and 300 mg/kg creatine (Group Cs/La + Cr) during the entire experimental period. Our results showed that animals in the Cs/Cr and Cs/La + Cr groups presented significantly decreased corticosterone levels compared to group Cs (p working memory task, compared to all other groups (p memory retention compared to controls (p working memory efficiency, and, when co-administrated with l-arginine, improves reference memory retention, a phenomenon that is possibly associated with increased creatine/phosphocreatine levels and l-arginine-derived NO synthesis.

  19. 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.

  20. 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.

  1. 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 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.

  2. 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.

  3. Stressed out or subjective acquisition of competence – how do veterinary students see their curative work placement?

    Directory of Open Access Journals (Sweden)

    Dilly, Marc

    2016-02-01

    Full Text Available 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.

  4. Classification of acute stress using linear and non-linear heart rate variability analysis derived from sternal ECG.

    Science.gov (United States)

    Tanev, George; Saadi, Dorthe B; Hoppe, Karsten; Sorensen, Helge B D

    2014-01-01

    Chronic stress detection is an important factor in predicting and reducing the risk of cardiovascular disease. This work is a pilot study with a focus on developing a method for detecting short-term psychophysiological changes through heart rate variability (HRV) features. The purpose of this pilot study is to establish and to gain insight on a set of features that could be used to detect psychophysiological changes that occur during chronic stress. This study elicited four different types of arousal by images, sounds, mental tasks and rest, and classified them using linear and non-linear HRV features from electrocardiograms (ECG) acquired by the wireless wearable ePatch® recorder. The highest recognition rates were acquired for the neutral stage (90%), the acute stress stage (80%) and the baseline stage (80%) by sample entropy, detrended fluctuation analysis and normalized high frequency features. Standardizing non-linear HRV features for each subject was found to be an important factor for the improvement of the classification results.

  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...Cigarette smoking and oral contra- ceptive use influence women’s lipid, lipoprotein, and cardiovascular responses during stress. Health Psychol 9(6

  6. 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

  7. Behaviour of S 355JO steel subjected to uniaxial stress at lowered ...

    Indian Academy of Sciences (India)

    Short-time creep tests for selected constant stresses at selected temperatures were curried out. Uniaxial creep behaviour for selected creep test was modeled by the rheological model. The creep curve determined by modeling procedure was compared with experimentally obtained one. Also, notch impact energy test, using ...

  8. Artemisinin production and precursor ratio in full grown Artemisia annua L. plants subjected to external stress

    NARCIS (Netherlands)

    Kjaer, A.; Verstappen, F.W.A.; Bouwmeester, H.J.; Ivarsen, E.; Frette, X.; Christensen, L.P.; Grevsen, K.; Jensen, M.

    2013-01-01

    The concentration of the lifesaving antimalarial compound artemisinin (AN) in cultivated Artemisia annua (A. annua) plants is relatively low, and thus research in improving the content is important. In the present study, external stress was applied to adult plants of A. annua and the effect was

  9. 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…

  10. 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 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.

  11. 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.

    2017-08-01

    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.

  12. 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.

  13. 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.

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

    Science.gov (United States)

    van der Zwan, Judith Esi; de Vente, Wieke; Huizink, Anja C; Bögels, Susan M; de Bruin, Esther I

    2015-12-01

    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 stress and its related symptoms. We randomly allocated 126 participants to PA, MM, or HRV-BF upon enrollment, of whom 76 agreed to participate. The interventions consisted of psycho-education and an introduction to the specific intervention techniques and 5 weeks of daily exercises at home. The PA exercises consisted of a vigorous-intensity activity of free choice. The MM exercises consisted of guided mindfulness meditation. The HRV-BF exercises consisted of slow breathing with a heart rate variability biofeedback device. Participants received daily reminders for their exercises and were contacted weekly to monitor their progress. They completed questionnaires prior to, directly after, and 6 weeks after the intervention. Results indicated an overall beneficial effect consisting of reduced stress, anxiety and depressive symptoms, and improved psychological well-being and sleep quality. No significant between-intervention effect was found, suggesting that PA, MM, and HRV-BF are equally effective in reducing stress and its related symptoms. These self-help interventions provide easily accessible help for people with stress complaints.

  15. [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.

  16. Heart rate as a sublethal indicator of thermal stress in juvenile freshwater mussels.

    Science.gov (United States)

    Pandolfo, Tamara J; Cope, W Gregory; Arellano, Consuelo

    2009-11-01

    Freshwater mussels (Unionoida) are one of the most sensitive and rapidly declining faunal groups in the world. Rising water temperatures, caused by industrial discharges, land development, or climate change can further challenge threatened unionid communities. The direct relationship between heart rate and temperature in ectotherms enables the use of heart rate as an indicator of whole-animal thermal stress. The purpose of this study was to assess the utility of heart rate as an indicator of thermal stress in freshwater mussels. Seven species of juvenile mussels (Lampsilis siliquoidea, Potamilus alatus, Ligumia recta, Ellipsaria lineolata, Megalonaias nervosa, Alasmidonta varicosa, and Villosa delumbis) were evaluated in response to a range of experimental temperatures (20-36 degrees C) at three acclimation temperatures (17, 22, and 27 degrees C). Heart rate was measured by direct visual observation through transparent mussel shells. The average heart rate for all 7 species at 20 degrees C was 55bpm, with a range from 38bpm (L. recta) to 65bpm (P. alatus). L. recta and V. delumbis exhibited significant changes in heart rate with increasing temperature at each of the three acclimation temperatures. The use of heart rate appears to be a suitable indicator of thermal stress in some unionid mussels.

  17. 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.

  18. α-Tocopherol, ascorbic acid, and β-carotene protect against oxidative stress but reveal no direct influence on p53 expression in rats subjected to stress.

    Science.gov (United States)

    Wawrzyniak, Agata; Górnicka, Magdalena; Hamułka, Jadwiga; Gajewska, Małgorzata; Drywień, Małgorzata; Pierzynowska, Jolanta; Gronowska-Senger, Anna

    2013-10-01

    We hypothesized that α-tocopherol, ascorbic acid, and β-carotene, either applied individually or in combination, would modulate redox homeostasis and affect the regulation of genes involved in DNA repair under stress conditions. To test this hypothesis, we analyzed the influence of these vitamins, either supplied individually or in combination, on the plasma lipid peroxide level and the hepatic level of 8-hydroxy-2'-deoxyguanosine in rats. We also evaluated the expression of p53 and Mdm2 protein in the intestinal epithelium, as these proteins are involved in the cellular regulation of DNA damage repair. Male Wistar rats (n = 112) were supplemented with α-tocopherol (2 mg), ascorbic acid (12 mg), and β-carotene (1 mg), both individually and in combination, for 14 days; 32 control rats were treated with placebo. Half of the animals in each group (n = 8) were subjected to 15-minute treadmill running at 20 m/min to cause exercise-induced oxidative stress. A statistically significant reduction in lipid peroxide levels was observed in the plasma of rats subjected to exercise and given 2 or 3 of the antioxidants (P p53 protein expression were observed both in exercised and nonexercised animals, especially when the studied vitamins were administered in combination. Our findings suggest that α-tocopherol, ascorbic acid, and β-carotene, when given concurrently, have primarily antioxidant effects on lipids under stress but do not significantly affect the regulation of p53 gene expression. © 2013 Elsevier Inc. All rights reserved.

  19. 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.

  20. Delayed heart rate recovery after adenosine stress testing with supplemental arm exercise predicts mortality.

    Science.gov (United States)

    Akutsu, Yasushi; Gregory, Shawn A; Kardan, Arash; Zervos, Gerasimos D; Thomas, Gregory S; Gewirtz, Henry; Yasuda, Tsunehiro

    2009-01-01

    Delayed heart rate (HR) recovery after treadmill exercise testing predicts mortality. Patients with suspected ischemic heart disease who cannot perform adequate treadmill exercise are typically evaluated with pharmacological stress myocardial perfusion imaging (MPI) studies, but little prognostic significance has been attributed to the hemodynamic response to vasodilator stress testing with low-level exercise. We hypothesized that a delay in HR recovery after adenosine stress testing with arm exercise is associated with increased mortality. Technetium 99m-Sestamibi MPI was performed in 1,455 consecutive patients (70 +/- 12 years, 50.2% men) with adenosine stress and supplemental arm exercise. HRs were recorded at rest, continuously during infusion, and then 5 minutes post-infusion. Delayed HR recovery was defined as a decline of mortality (16.5% vs 5.3% in those with normal HR recovery, P testing with arm exercise is a readily available and powerful predictor of all-cause mortality.

  1. 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.

  2. Subjective Ratings of Annoyance Produced by Rotary-Wing Aircraft Noise

    Science.gov (United States)

    1977-05-01

    nov "is ossoLaTa Unclassified SECURITY CLASSFICATION 5.Frs PARE FW- D Eneredt- 𔃻 5 7 W Unclassified 69CURITY CLASIFICATION OF THIS PAG9(Vhw Da...paths followed during the various maneuvers relative to the location of the observers rendering the ratings. The observers were 25 adults hired on a

  3. Subjective ratings of prospective memory deficits in chronic heavy alcohol users

    OpenAIRE

    Heffernan, Tom; Moss, Mark; Ling, Jonathan

    2002-01-01

    Chronic alcohol abuse has a detrimental effect on retrospective memory. Less is known about its putative effects on everyday memory. This study looked at self-ratings of prospective memory (PM) (memory for future events). After controlling for other drug and strategy use, chronic heavy alcohol users showed global impairments in PM, when compared to matched controls. The underlying mechanisms are discussed.

  4. Effects of Aerobic Exercise Based upon Heart Rate at Aerobic Threshold in Obese Elderly Subjects with Type 2 Diabetes

    Directory of Open Access Journals (Sweden)

    Gian Pietro Emerenziani

    2015-01-01

    Full Text Available In obese diabetic subjects, a correct life style, including diet and physical activity, is part of a correct intervention protocol. Thus, the aim of this study was to evaluate the effects of aerobic training intervention, based on heart rate at aerobic gas exchange threshold (AerTge, on clinical and physiological parameters in obese elderly subjects with type 2 diabetes (OT2DM. Thirty OT2DM subjects were randomly assigned to an intervention (IG or control group (CG. The IG performed a supervised aerobic exercise training based on heart rate at AerTge whereas CG maintained their usual lifestyle. Anthropometric measures, blood analysis, peak oxygen consumption (V˙O2peak, metabolic equivalent (METpeak, work rate (WRpeak, and WRAerTge were assessed at baseline and after intervention. After training, patients enrolled in the IG had significantly higher (P<0.001 V˙O2peak, METpeak, WRpeak, and WRAerTge and significantly lower (P<0.005 weight, BMI, %FM, and waist circumference than before intervention. Both IG and CG subjects had lower glycated haemoglobin levels after intervention period. No significant differences were found for all the other parameters between pre- and posttraining and between groups. Aerobic exercise prescription based upon HR at AerTge could be a valuable physical intervention tool to improve the fitness level and metabolic equilibrium in OT2DM patients.

  5. The Relation of Arm Exercise Peak Heart Rate to Stress Test Results and Outcome.

    Science.gov (United States)

    Xian, Hong; Liu, Weijian; Marshall, Cynthia; Chandiramani, Pooja; Bainter, Emily; Martin, Wade H

    2016-09-01

    Arm exercise is an alternative to pharmacologic stress testing for >50% of patients unable to perform treadmill exercise, but no data exist regarding the effect of attained peak arm exercise heart rate on test sensitivity. Thus, the purpose of this investigation was to characterize the relationship of peak arm exercise heart rate responses to abnormal stress test findings, coronary revascularization, and mortality in patients unable to perform leg exercise. From 1997 until 2002, arm cycle ergometer stress tests were performed in 443 consecutive veterans age 64.1 yr (11.0 yr) (mean (SD)), of whom 253 also underwent myocardial perfusion imaging (MPI). Patients were categorized by frequency distributions of quartiles of percentage age-predicted peak heart rate (APPHR), heart rate reserve (HRR), and peak heart rate-systolic blood pressure product (PRPP). Exercise-induced ST-segment depression, abnormal MPI findings, coronary revascularization, and 12.0-yr (1.3 yr) Kaplan-Meier all-cause and cardiovascular mortality plots were then characterized by quartiles of APPHR, HRR, and PRPP. A reduced frequency of abnormal arm exercise ECG results was associated only with the lowest quartile of APPHR (≤69%) and HRR (≤43%), whereas higher frequency of abnormal MPI findings exhibited an inverse relationship trend with lower APPHR (P = 0.10) and HRR (P = 0.12). There was a strong inverse association of APPHR, HRR, and PRPP with all-cause (all P ≤ 0.01) and cardiovascular (P Arm exercise ECG stress test sensitivity is only reduced at ≤69% APPHR or ≤43% HRR, whereas arm exercise MPI sensitivity and referral for coronary revascularization after arm exercise stress testing are not adversely affected by even a severely blunted peak heart rate. However, both all-cause mortality and cardiovascular mortality are strongly and inversely related to APPHR and HRR.

  6. Functional analysis of stress protein data in a flor yeast subjected to a biofilm forming condition

    Directory of Open Access Journals (Sweden)

    Jaime Moreno-García

    2016-06-01

    Full Text Available In this data article, an OFFGEL fractionator coupled to LTQ Orbitrap XL MS equipment and a SGD filtering were used to detect in a biofilm-forming flor yeast strain, the maximum possible number of stress proteins under the first stage of a biofilm formation conditions (BFC and under an initial stage of fermentation used as reference, so-called non-biofilm formation condition (NBFC. Protein functional analysis – based on cellular components and biological process GO terms – was performed for these proteins through the SGD Gene Ontology Slim Mapper tool. A detailed analysis and interpretation of the data can be found in “Stress responsive proteins of a flor yeast strain during the early stages of biofilm formation” [1].

  7. Chemo-Plasticity of Clays Subjected to Stress and Flow of a Single Contaminant

    Science.gov (United States)

    Hueckel, T.

    1997-01-01

    Isothermal chemo-elasto-plasticity of clays is discussed, to describe strains induced in clay by permeation of it with a low dielectric constant organic contaminant, in the presence of stress. The strain is crucial in controlling permeability changes in chemically affected clay barriers of landfills and impoundments. The theory encompasses chemical softening or yield surface reduction, coefficient of chemical reversible expansion or contraction due to mass concentration increase, as well as chemical sensitivity of bulk plastic modulus. The experiments on chemistry and stress dependent permeability of Sarnia clay performed by Fernandez and Quigley (1985, 1991) are interpreted using this model. The numerical representations of the chemo-plastic softening function and the chemo-elastic strain function, as well as plastic bulk modulus sensitivity to concentration are evaluated for dioxane and ethanol. Specific requirements for the tests for chemo-plastic behavior of clays are discussed.

  8. Associations of objectively measured physical activity with daily mood ratings and psychophysiological stress responses in women.

    Science.gov (United States)

    Poole, Lydia; Steptoe, Andrew; Wawrzyniak, Andrew J; Bostock, Sophie; Mitchell, Ellen S; Hamer, Mark

    2011-08-01

    The aim of this study was to examine associations of objectively measured physical activity with daily mood ratings and psychophysiological stress responses. We recruited 40 healthy females (aged 28.7 ± 6.1 yrs) who completed a once-a-day mood rating scale for 7 days, along with a 7-day assessment of physical activity using accelerometers and psychophysiological stress testing. The findings suggest that levels of physical activity as measured using an accelerometer are associated with both depressive symptoms over the past 2 weeks (CES-D) (r = - .33, p = .038) and with daily positive emotional style (r = .49, p = .001). The relationship between physical activity and positive emotional style remained after controlling for age, body mass index, and negative emotional style (t = 3.31, p = .002). Physical activity was not related to any psychophysiological stress responses. Copyright © 2011 Society for Psychophysiological Research.

  9. Predicted stresses and strains in fused biconical taper couplers subjected to tension.

    Science.gov (United States)

    Suhir, E

    1993-06-20

    In fused biconical taper (FBT) couplers, the cores of the fibers are positioned close to each other. In order to bring the cores of the fibers in close proximity, the cladding in the fused midportion of the coupler has to be made thin. At the same time the coupler must be sufficiently strong, both on a short- and a long-time scale, and must be able to withstand appreciable axial deformations. These can be caused by the thermal contraction mismatch of the coupler with its substrate or can be due to a deliberate prestressing of the coupler structure in order to improve its dynamic stability. In this study an easy-to-apply analytical stress model is developed for the evaluation of stresses and strains in FBT couplers from the expected or measured total elongation. In the analysis the nonprismaticity of the coupler structure as well as the nonlinear behavior of the material was considered. The numerical example has been carried out for a coupler that is intended for undersea applications. The results obtained can be used in the stress-strain analyses and physical design of light-wave FBT couplers.

  10. Phenotypic heterogeneity is a selected trait in natural yeast populations subject to environmental stress

    Science.gov (United States)

    Holland, Sara L; Reader, Tom; Dyer, Paul S; Avery, Simon V

    2014-01-01

    Populations of genetically uniform microorganisms exhibit phenotypic heterogeneity, where individual cells have varying phenotypes. Such phenotypes include fitness-determining traits. Phenotypic heterogeneity has been linked to increased population-level fitness in laboratory studies, but its adaptive significance for wild microorganisms in the natural environment is unknown. Here, we addressed this by testing heterogeneity in yeast isolates from diverse environmental sites, each polluted with a different principal contaminant, as well as from corresponding control locations. We found that cell-to-cell heterogeneity (in resistance to the appropriate principal pollutant) was prevalent in the wild yeast isolates. Moreover, isolates with the highest heterogeneity were consistently observed in the polluted environments, indicating that heterogeneity is positively related to survival in adverse conditions in the wild. This relationship with survival was stronger than for the property of mean resistance (IC50) of an isolate. Therefore, heterogeneity could be the major determinant of microbial survival in adverse conditions. Indeed, growth assays indicated that isolates with high heterogeneities had a significant competitive advantage during stress. Analysis of yeasts after cultivation for ≥ 500 generations additionally showed that high heterogeneity evolved as a heritable trait during stress. The results showed that environmental stress selects for wild microorganisms with high levels of phenotypic heterogeneity. PMID:24000788

  11. Sweating Rates of Dairy and Feedlot Cows in Stressful Thermal Environments

    Science.gov (United States)

    Sweating rates from heat-stressed dairy and feedlot cows were measured using a portable calorimeter. Measurements were made when cows were in shade and exposed to direct sunlight (120 to 1100 W/m2) under different air velocities (0.1 to 1.8 m/s). The effect of color of hair coat (black and white) on...

  12. Genetic influences on heart rate variability at rest and during stress

    NARCIS (Netherlands)

    Wang, Xiaoling; Ding, Xiuhua; Su, Shaoyong; Li, Zhibin; Riese, Harriette; Thayer, Julian F.; Treiber, Frank; Snieder, Harold

    We tested whether the heritability of heart rate variability (HRV) under stress is different from rest and its dependency on ethnicity or gender. HRV indexed by root mean square of successive differences (RMSSD) and high-frequency (HF) power was measured at rest and during 3 stressors in 427

  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...

  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. Growth rate, protein:RNA ratio and stoichiometric homeostasis of submerged macrophytes under eutrophication stress

    OpenAIRE

    Xing W.; Shi Q.; Liu H.; Liu G.

    2016-01-01

    Growth rate hypothesis (GRH) and stoichiometric homeostasis of photoautotrophs have always been questioned. However, little is known about GRH and stoichiometric homeostasis of aquatic plants, especially submerged macrophytes. Therefore, we aim to test the GRH and explore stoichiometric homeostasis of four freshwater submerged macrophytes under eutrophication stress. At the single species level and the multi-species level, N:P ratios ...

  16. 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.

  17. Dynamic Evaluation of Acrylonitrile Butadiene Styrene Subjected to High-Strain-Rate Compressive Loads

    Science.gov (United States)

    2014-12-01

    Conclusions 10 5. References 11 Distribution List 13 iv List of Figures Figure 1. ASTM D 638-03 dog bone...1. ASTM D 638-03 dog bone. When designing the specimen for tensile testing, it is important that the tensile specimen be built such that the...2006, 45 (1), 18–24. 8. Lee, W. S.; Lin, C. F. Plastic Deformation and Fracture Behaviour of Ti–6Al–4V Alloy Loaded With High Strain Rate Under

  18. Clearance and synthesis rates of beta 2-microglobulin in patients undergoing hemodialysis and in normal subjects

    Energy Technology Data Exchange (ETDEWEB)

    Floege, J.; Bartsch, A.; Schulze, M.; Shaldon, S.; Koch, K.M.; Smeby, L.C. (Department of Nephrology, University Hospital of Hannover (Germany))

    1991-08-01

    Retention of {beta} 2-microglobulin in patients undergoing hemodialysis is associated with a {beta} 2-microglobulin-derived amyloidosis. Removal of {beta} 2-microglobulin by renal replacement therapy has been proposed for the prevention of this amyloidosis. Currently, however, data on the {beta} 2-microglobulin synthesis rate in patients undergoing hemodialysis are scarce, and consequently it remains speculative how much removal would be necessary to counterbalance synthesis. The plasma kinetics of iodine 131-labeled {beta} 2-microglobulin were therefore examined in 11 patients with anuria who were undergoing long-term hemodialysis. Five healthy persons served as controls. Kinetic modeling of the plasma curves showed that the data fitted a two-pool model (r2 greater than 0.96) consisting of a rapid 2 to 4 hour distribution phase followed by a less steep curve, described by the plasma (metabolic) clearance (Clp). Synthetic rates were calculated from Clp and the {beta} 2-microglobulin steady state plasma concentration (plus {beta} 2-microglobulin removal during hemodialysis in the case of high flux hemodialysis). The results showed a significantly higher Clp in normal controls as compared with patients undergoing hemodialysis (65.5 {plus minus} 12.8 ml/min (mean {plus minus} SD) versus 3.4 {plus minus} 0.7 ml/min). In contrast, the {beta} 2-microglobulin synthesis rate in the patient group (3.10 {plus minus} 0.79 mg/kg/day) was not significantly different from that of normal controls (2.40 {plus minus} 0.67 mg/kg/day), which was due to markedly elevated {beta} 2-microglobulin plasma concentrations in the patients (37.6 {plus minus} 14.1 mg/L vs 1.92 {plus minus} 0.27 mg/L). These findings suggest that the presence of end-stage renal disease does not have a significant impact on the beta 2-microglobulin generation rate.

  19. Effects of alcohol on subjective ratings of prospective and everyday memory deficits

    OpenAIRE

    Ling, Jonathan; Heffernan, Tom; Buchanan, Tom; Rodgers, Jacqui; Scholey, Andrew; Parrott, Andrew

    2003-01-01

    Background: Research has shown that heavy alcohol use has a detrimental effect on retrospective memory. Less is known about the effect of alcohol on everyday memory. Methods: This study examined self-ratings of two aspects of memory performance: prospective memory (for example, forgetting to pass on a message) and everyday memory (measured by cognitive failures, such as telling someone a joke that you have told them before). To ensure anonymity and expand on the numbers of participants used i...

  20. 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

  1. Recommendations for aerobic endurance training based on subjective ratings of perceived exertion in healthy seniors.

    Science.gov (United States)

    Donath, Lars; Zahner, Lukas; Cordes, Mareike; Hanssen, Henner; Schmidt-Trucksäss, Aarno; Faude, Oliver

    2013-01-01

    The study investigated physiological responses during 2-km walking at a certain intensity of a previously performed maximal exercise test where moderate perceived exertion was reported. Twenty seniors were examined by an incremental walking treadmill test to obtain maximal oxygen uptake (VO2max). A submaximal 2-km walking test was applied 1 wk later. The corresponding moderate perceived exertion (4 on the CR-10 scale) during the VO2max test was applied to the 2-km treadmill test. Moderate exertion (mean rating of perceived exertion [RPE]: 4 ± 1) led to 76% ± 8% of VO2max and 79% ± 6% of maximal heart rate. RPE values drifted with a significant time effect (p = .001, η(p) = .58) during the 2-km test from 3 ± 0.7 to 4.6 ± 0.8. Total energy expenditure (EE) was 3.3 ± 0.5 kcal/kg. No gender differences in ventilatory, heart-rate, or EE data occurred. Brisk walking at moderate RPE of 3-5 would lead to a beneficial physiological response during endurance training and a weekly EE of nearly 1,200 kcal when exercising 5 times/wk for 30 min.

  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. 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...

  4. 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…

  5. AN ELASTIC STRESS ANALYSIS FOR A POLYMER MATRIX COMPOSITE CANTILEVER BEAM SUBJECTED TO A SINGLE TRANSVERSE FORCE

    Directory of Open Access Journals (Sweden)

    Ayla TEKİN

    2004-03-01

    Full Text Available In this study, elasto-plastic stress analysis is carried out in a polymer matrix composite cantilever beam of arbitrary fiber orientation subjected to a single transverse force applied to the free end by using the anisotropic elasticity theory. The residual stress component of ?x and yield points are determined for 0°, 30°, 45°, 60° and 90° fiber orientation angles. The yielding begins for 0° and 90° fiber orientation angles at the upper and lower surfaces of the beam at the same distances from the free end. It is seen that the yielding begins for 30°, 45° and 60° fiber orientation angles at the upper surface of the beam. The intensity of the residual stress component of ?x is maximum at the upper and lower surfaces of the beam. In this study, the residual stress component of ?x obtained for the polymer matrix composite thermoplastic cantilever beam reinforced by reinforced unidirectional fibers is compared with that of the thermoplastic cantilever beam reinforced by woven Cr-Ni steel fibers.

  6. 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.

  7. Peritraumatic Behavior Questionnaire - Observer Rated: Validation of the objective version of a measure for combat-related peritraumatic stress.

    Science.gov (United States)

    Agorastos, Agorastos; Angkaw, Abigail C; Johnson, Heather E; Hansen, Christian J; Cook, Camille V; Baker, Dewleen G

    2016-06-22

    To validate the first third-person-rated measure assessing combat-related peritraumatic stress symptoms and evaluate its psychometric properties and war-zone applicability. The valid assessment of peritraumatic symptoms in the theater of military operations represents a significant challenge in combat-related, mental health research, which mainly relies on retrospective, subjective self-report ratings. This longitudinal observational study used data from actively deployed troops to correlate third-person observer ratings of deployment peritraumatic behaviors [Peritraumatic Behavior Questionnaire - Observer Rated (PBQ-OR)] collected on a bi-monthly basis with post-deployment (1-wk follow-up) ratings of the previously validated PBQ self-rate version (PBQ-SR), and (3-mo follow-up) clinician assessed and self-report posttraumatic stress disorder (PTSD) symptoms (Clinician Administered PTSD Scale, PTSD Checklist). Cronbach's alpha (α) and correlation coefficients were calculated to assess internal reliability and concurrent validity respectively. Eight hundred and sixty male Marines were included in this study after signing informed consents at pre-deployment (mean age 23.2 ± 2.6 years). Although our findings were limited by an overall sparse return rate of PBQ-OR ratings, the main results indicate satisfactory psychometric properties with good internal consistency for the PBQ-OR (α = 0.88) and high convergent and concurrent validity with 1-wk post-deployment PBQ-SR ratings and 3-mo posttraumatic stress symptoms. Overall, later PBQ-OR report date was associated with higher correlation between PBQ-OR and post-deployment measures. Kappa analysis between PBQ-OR and PBQ-SR single items, showed best agreement in questions relating of mortal peril, desire for revenge, and experience of intense physical reactions. Logistic regression demonstrated satisfactory predictive validity of PBQ-OR total score with respect to PTSD caseness (OR = 1.0513; 95%CI: 1.011-1.093; P = 0

  8. 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.

  9. Oxidative DNA damage and oxidative stress in subjects occupationally exposed to nitrous oxide (N(2)O).

    Science.gov (United States)

    Wrońska-Nofer, Teresa; Nofer, Jerzy-Roch; Jajte, Jolanta; Dziubałtowska, Elżbieta; Szymczak, Wiesław; Krajewski, Wojciech; Wąsowicz, Wojciech; Rydzyński, Konrad

    2012-03-01

    Occupational exposure to nitrous oxide (N(2)O) and/or halogenated hydrocarbons has been suggested to induce damage of genetic material, but the underlying mechanisms remain obscure. This study investigated the role of oxidative processes in the genotoxicity associated with exposure to waste anaesthetic gases. The study was performed in 36 female nurses and in 36 unexposed female health care workers matched for age and employment duration. Genotoxic effects were examined by Comet test modification employing formamidopyrimidine glycosylase (FPG) that allows assessment of oxidative DNA damage. Reactive oxygen species (ROS) in leukocytes were investigated by fluorescence spectroscopy with 2',7'-dichlorofluorescin diacetate. Oxidative stress markers including 8-iso-prostaglandin F(2α) (8-iso-PGF(2α)), thiobarbituric acid-reacive substances (TBARS), α-tocopherol, and glutathione peroxidise (GPX) activity were measured immuno- or colorimetrically. N(2)O, sevoflurane and isoflurane were monitored by gas chromatography and mass spectrometry. The study documents for the first time the positive correlation between the oxidative DNA damage and the N(2)O levels in the ambient air. By contrast, no association was observed between genotoxic effects and sevoflurane or isoflurane. In addition, ROS generation and plasma and urine concentrations of TBARS and 8-iso-PGF(2α), respectively, were elevated, while GPX activity was reduced in nurses exposed to waste anaesthetic gases. Path analysis pointed to a causal relationship between N(2)O exposure, oxidative stress and DNA damage. Occupational exposure to N(2)O is associated with increased oxidative DNA damage and the level of exposure plays a critical role in this regard. Increased oxidative stress may represent a mechanistic link between chronic N(2)O exposure and genotoxicity. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. 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.

  11. Stress Recovery Effects of High- and Low-Frequency Amplified Music on Heart Rate Variability

    Directory of Open Access Journals (Sweden)

    Yoshie Nakajima

    2016-01-01

    Full Text Available 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.

  12. 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.

  13. Entropy-rate clustering: cluster analysis via maximizing a submodular function subject to a matroid constraint.

    Science.gov (United States)

    Liu, Ming-Yu; Tuzel, Oncel; Ramalingam, Srikumar; Chellappa, Rama

    2014-01-01

    We propose a new objective function for clustering. This objective function consists of two components: the entropy rate of a random walk on a graph and a balancing term. The entropy rate favors formation of compact and homogeneous clusters, while the balancing function encourages clusters with similar sizes and penalizes larger clusters that aggressively group samples. We present a novel graph construction for the graph associated with the data and show that this construction induces a matroid--a combinatorial structure that generalizes the concept of linear independence in vector spaces. The clustering result is given by the graph topology that maximizes the objective function under the matroid constraint. By exploiting the submodular and monotonic properties of the objective function, we develop an efficient greedy algorithm. Furthermore, we prove an approximation bound of (1/2) for the optimality of the greedy solution. We validate the proposed algorithm on various benchmarks and show its competitive performances with respect to popular clustering algorithms. We further apply it for the task of superpixel segmentation. Experiments on the Berkeley segmentation data set reveal its superior performances over the state-of-the-art superpixel segmentation algorithms in all the standard evaluation metrics.

  14. Relation between food intake and visual analogue scale ratings of appetite and other sensations in healthy older and young subjects.

    Science.gov (United States)

    Parker, B A; Sturm, K; MacIntosh, C G; Feinle, C; Horowitz, M; Chapman, I M

    2004-02-01

    Visual analogue scales are widely used in appetite research, yet the validity of these scales to evaluate appetite and mood has not been assessed in older subjects. The aim of this study was to determine the relations between food intake and visual analogue scale (VAS) ratings of appetite and nonappetite sensations in healthy older and young subjects. Retrospective combined analysis of four single-blind, randomised, controlled appetite studies. All studies were conducted in the University of Adelaide, Department of Medicine, Adelaide, Australia. A total of 45 healthy young men (n=24) and women (n=21) aged 18-35 y and 45 healthy older men (n=24) and women (n=21) aged 65-85 y were recruited by advertisement. Oral, intraduodenal or intravenous administration of treatments which suppressed food intake were compared to control. Up to 90 min after treatment, a test meal was offered and subjects ate freely for between 30 and 60 min. Perceptions were assessed by 100-mm visual analogue scales administered at regular intervals. Food intake at the test meal was positively related to perceptions of hunger, drowsiness, and calmness at both baseline and premeal (r>0.16, P 0.2, P<0.05) in both older and young subjects. Food intake was related to VAS ratings at least as strongly, if not more so, in older as in young subjects. These observations (i) confirm that food intake is related to perceptions of hunger and fullness as assessed by VAS in healthy older and young subjects, and (ii) suggest that sensations, not obviously associated with appetite, including 'drowsiness' and 'calmness', are also associated with food intake.

  15. C-reactive protein, heart rate variability and prognosis in community subjects with no apparent heart disease

    DEFF Research Database (Denmark)

    Sajadieh, A; Nielsen, OW; Rasmussen, Verner

    2006-01-01

    OBJECTIVES: Increased C-reactive protein (CRP) and reduced heart rate variability (HRV) both indicate poor prognosis. An inverse association between HRV and CRP has been reported, suggesting an interaction between inflammatory and autonomic systems. However, the prognostic impact...... of this interaction has not been studied. We thus investigated the prognostic impact of CRP, HRV and their combinations. DESIGN: Population-based study. SUBJECTS: A total of 638 middle-aged and elderly subjects with no apparent heart disease from community. METHODS: All were studied by clinical and laboratory...... of four HRV measures were significantly associated with increased rate of death or myocardial infarction. In a Cox model with CRP >or=2.5 microg mL(-1), standard deviation for the mean value of the time between normal complexes...

  16. Evaluation of Stress Response During Mesiodens Extraction Under General Anesthesia Using Heart Rate Variability.

    Science.gov (United States)

    Hwang, Hye-Won; Hyun, Hong-Keun; Kim, Young-Jae; Kim, Jung-Wook; Shin, Teo Jeon

    2017-05-01

    Stress related to dental treatment can be associated with negative outcomes. Heart rate variability (HRV) is an objective measurement of autonomic nervous system activity. Therefore, HRV was used to identify autonomic nervous system reactions during mesiodens extraction under general anesthesia in children. Electrocardiography was performed with customized software during treatment. HRV parameters were analyzed according to time and frequency domains during each dental procedure (local anesthesia, incision, flap, bone removal, extraction of mesiodens, and suturing). The relations of HRV parameters to age also were determined. Total autonomic nervous system activity decreased markedly after local anesthesia injection. Depending on the responses of sympathetic nerve activity, patients were categorized in a stress group and a nonstress group. The ratio of low-frequency power (LF) to high-frequency power (HF), an indication of sympathetic and parasympathetic balance, increased in the stress group after incision and flap formation. Conversely, the LF/HF ratio decreased during treatment in the nonstress group. However, HR, widely used to evaluate stress responses, did not change statistically during mesiodens extraction in either group. HRV parameters did not differ statistically according to age. The internal stress related to mesiodens extraction can be evaluated more objectively with HRV parameters than with conventional methods. Sympathetic nerve activity in the stress group differed from that in the nonstress group during the treatment procedures. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  17. Prediction of FV520B Steel Flow Stresses at High Temperature and Strain Rates

    Science.gov (United States)

    Han, Xiaolan; Zhao, Shengdun; Zhang, Chenyang; Fan, Shuqin; Xu, Fan

    2015-10-01

    In order to develop reliable constitutive equations for the simulation, the hot deformation behavior of FV520B steel was investigated through isothermal compression tests in a wide range of temperatures from 900 °C to 1100 °C at an interval of 50 °C and strain rate from 0.01 to 10 s-1 on Gleeble-1500D simulator. The effects of temperature and strain rate on deformation behavior were represented by Zener-Holloman parameter in an exponent-type equation of Arrhenius constitutive. The influence of strain was incorporated in the constitutive analysis by material constants expressed as a polynomial function of strain. The constitutive equation (considering the compensation of strain) could precisely predict the flow stress only at strain rate 0.01 s-1 except at the temperatures of 900 °C and 1000 °C, whereas the flow stress predicted by a modified equation (incorporating both the strain and strain rate) demonstrated a well agreement with the experimental data throughout the entire range of temperatures and strain rates. Correlation coefficient (R) of 0.988 and average absolute relative error (AARE) of 5.7% verified the validity of developed equation from statistical analysis, which further confirmed that the modified constitutive equation could accurately predict the flow stress of FV520B steel.

  18. Stress Ratio Effects on Crack Opening Loads and Crack Growth Rates in Aluminum Alloy 2024

    Science.gov (United States)

    Riddell, William T.; Piascik, Robert S.

    1998-01-01

    The effects of stress ratio (R) and crack opening behavior on fatigue crack growth rates (da/dN) for aluminum alloy (AA) 2024-T3 were investigated using constant-delta K testing, closure measurements, and fractography. Fatigue crack growth rates were obtained for a range of delta K and stress ratios. Results show that constant delta K fatigue crack growth for R ranging from near 0 to 1 is divided into three regions. In Region 1, at low R, da/dN increases with increasing R. In Region 2, at intermediate R, fatigue crack growth rates are relatively independent of R. In Region 3, at high R, further increases in da/dN are observed with increasing R.

  19. A mathematical model for storied buildings subjected to automatic loom stresses. [vibration of weaving mill

    Science.gov (United States)

    Stan, A.; Munteanu, M.

    1974-01-01

    Expressions are derived for the displacements of a many storied building subjected to the action of classical weaving looms located at different levels of the building. The building is regarded as a vertical fixed beam with a uniformly distributed mass as well as concentrated masses at each level. The calculation relations are obtained on the assumption of harmonic variation of the forces acting at each level as well as the assumption of narrow band stationary random excitatory forces.

  20. Comparison of GC-MS and NMR for metabolite profiling of rice subjected to submergence stress.

    Science.gov (United States)

    Barding, Gregory A; Béni, Szabolcs; Fukao, Takeshi; Bailey-Serres, Julia; Larive, Cynthia K

    2013-02-01

    Natural disasters such as drought, extreme temperatures, and flooding can severely impact crop production. Understanding the metabolic response of crops threatened with these disasters provides insights into biological response mechanisms that can influence survival. In this study, a comparative analysis of GC-MS and (1)H NMR results was conducted for wild-type and tolerant rice varieties stressed by up to 3 days of submergence and allowed 1 day of postsubmergence recovery. Most metabolomics studies are conducted using a single analytical platform. Each platform, however, has inherent advantages and disadvantages that can influence the analytical coverage of the metabolome. In this work, a more thorough analysis of the plant stress response was possible through the use of both (1)H NMR and GC-MS. Several metabolites, such as S-methyl methionine and the dipeptide alanylglycine, were only detected and quantified by (1)H NMR. The high dynamic range of NMR, as compared with that of the GC-TOF-MS used in this study, provided broad coverage of the metabolome in a single experiment. The sensitivity of GC-MS facilitated the quantitation of sugars, organic acids, and amino acids, some of which were not detected by NMR, and provided additional insights into the regulation of the TCA cycle. The combined metabolic information provided by (1)H NMR and GC-MS was essential for understanding the complex biochemical and molecular response of rice plants to submergence.

  1. Neuroprotective Effects of Castanea sativa Mill. Bark Extract in Human Neuroblastoma Cells Subjected to Oxidative Stress.

    Science.gov (United States)

    Brizi, Claudia; Santulli, Chiara; Micucci, Matteo; Budriesi, Roberta; Chiarini, Alberto; Aldinucci, Carlo; Frosini, Maria

    2016-02-01

    One of the major features of neurodegenerative disease is the selective vulnerability of different neuronal populations that are affected in a progressive and often stereotyped manner. Despite the susceptible neuronal population varies between diseases, oxidative stress is implicated as the major pathogenic process in all of them. Natural Extract of Castanea sativa Mill. bark (ENC), recently characterized in its phenolic composition, acts as antioxidant and cardioprotective agent. Its neuroprotettive properties, however, have never been investigated. The aim of this study was to assess neuroprotection of ENC in in vitro models of oxidative-stress-mediate injury. Human neuroblastoma SH-SY5Y cells treated with glutamate (50 mM for 24 h) or hydrogen peroxide (25 μM for 1 h followed by 24 with medium) were used. The results showed that the addition of ENC (1-50 μg/ml) to cell medium before the neuronal damage provided neuroprotection in both experimental models used, while its addition after the injury was ineffective. In conclusion, the present results suggest that ENC could be a valuable support as dietary supplement, combining beneficial preventive neuroprotettive effects with a high antioxidant activity. © 2015 Wiley Periodicals, Inc.

  2. 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

    2018-01-27

    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.

  3. [Stress dobutamine echocardiography or resting strain rate imaging to unveil an early symptomatic diabetic cardiomyopathy?

    Science.gov (United States)

    Aboukhoudir, F; Aboukhoudir, I; Rekik, S

    2017-11-01

    Diabetes mellitus has been associated with changes in the structure and function of the myocardium manifesting in the early stages of the disease as subtle systolic and diastolic dysfunction; myocardial strain imaging has recently been favored over dobutamine stress echocardiography for early detection of diabetic cardiomyopathy. We report a case of an elderly diabetic patient presenting with pulmonary edema in whom at rest echocardiographic parameters including strain rate were all within normal range, while dobutamine stress echocardiography induced a deep systolic deterioration unmasking an early-stage diabetic cardiomyopathy. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  4. 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

    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......: High resolution sagittal 3D T1w MP-RAGE scans were acquired from patients diagnosed with AD (n = 58,MMSE:21.6 ± 4.4), MCI subjects (n = 85,MMSE:27.2 ± 1.6), and HC (n = 75,MMSE:29.0 ± 1.3) at baseline, and at three and 12 months follow-up. Only subjects with three completed scans which all passed...... rates can be found in AD patients compared to HC and MCI. Even three months after baseline accelerated atrophy can be observed in AD compared to HC, however, the results indicate that three months is too short a period to distinguish the atrophy rates in AD and MCI. The results suggest that atrophy...

  5. 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.

  6. PKCα is genetically linked to memory capacity in healthy subjects and to risk for posttraumatic stress disorder in genocide survivors.

    Science.gov (United States)

    de Quervain, Dominique J-F; Kolassa, Iris-Tatjana; Ackermann, Sandra; Aerni, Amanda; Boesiger, Peter; Demougin, Philippe; Elbert, Thomas; Ertl, Verena; Gschwind, Leo; Hadziselimovic, Nils; Hanser, Edveena; Heck, Angela; Hieber, Petra; Huynh, Kim-Dung; Klarhöfer, Markus; Luechinger, Roger; Rasch, Björn; Scheffler, Klaus; Spalek, Klara; Stippich, Christoph; Vogler, Christian; Vukojevic, Vanja; Stetak, Attila; Papassotiropoulos, Andreas

    2012-05-29

    Strong memory of a traumatic event is thought to contribute to the development and symptoms of posttraumatic stress disorder (PTSD). Therefore, a genetic predisposition to build strong memories could lead to increased risk for PTSD after a traumatic event. Here we show that genetic variability of the gene encoding PKCα (PRKCA) was associated with memory capacity--including aversive memory--in nontraumatized subjects of European descent. This finding was replicated in an independent sample of nontraumatized subjects, who additionally underwent functional magnetic resonance imaging (fMRI). fMRI analysis revealed PRKCA genotype-dependent brain activation differences during successful encoding of aversive information. Further, the identified genetic variant was also related to traumatic memory and to the risk for PTSD in heavily traumatized survivors of the Rwandan genocide. Our results indicate a role for PKCα in memory and suggest a genetic link between memory and the risk for PTSD.

  7. Investigation of thermomechanical couplings, strain localization and shape memory properties in a shape memory polymer subjected to loading at various strain rates

    Science.gov (United States)

    Pieczyska, E. A.; Staszczak, M.; Maj, M.; Kowalczyk-Gajewska, K.; Golasiński, K.; Cristea, M.; Tobushi, H.; Hayashi, S.

    2016-08-01

    This paper presents experimental and modeling results of the effects of thermomechanical couplings occurring in a polyurethane shape memory polymer (SMP) subjected to tension at various strain rates within large strains. The SMP mechanical curves, recorded using a testing machine, and the related temperature changes, measured in a contactless manner using an IR camera, were used to investigate the polymer deformation process at various loading stages. The effects of thermomechanical couplings allowed the determination of the material yield point in the initial loading stage, the investigation of nucleation and development of the strain localization at larger strains and the estimation of the effects of thermoelastic behavior during the unloading process. The obtained stress-strain and thermal characteristics, the results of the dynamic mechanical analysis and estimated values of the shape fixity and shape recovery parameters confirmed that the shape memory polymer (T g = 45 °C) is characterized by good mechanical and shape memory properties, as well as high sensitivity to the strain rate. The mechanical response of the SMP subjected to tension was simulated using the finite element method and applying the large strain, two-phase model. Strain localization observed in the experiment was well reproduced in simulations and the temperature spots were correlated with the accumulated viscoplastic deformation of the SMP glassy phase.

  8. Effect of maternal stress on fetal heart rate assessed by vibroacoustic stimulation.

    Science.gov (United States)

    Makino, I; Matsuda, Y; Yoneyama, M; Hirasawa, K; Takagi, K; Ohta, H; Konishi, Y

    2009-01-01

    This study was designed to determine whether maternal stress levels, state and trait anxiety levels, and stress hormones affect fetal heart rate (FHR) patterns after vibroacoustic stimulation (VAS) at 30 weeks of gestation. A total of 24 healthy pregnant women with a single fetus pregnancy were enrolled. Corticotropin releasing hormone (CRH) and adrenocorticotropic hormone in maternal plasma and cortisol, and chromogranin A in saliva were measured. The FHR patterns after VAS were divided into three types: type I, a long period of acceleration or one acceleration lasting > 1 min or at least two accelerations lasting > 15 s; type II, a biphasic response with acceleration followed by deceleration; and type III, no response or prolonged deceleration. In the high trait anxiety group, CRH levels were significantly higher than in the low trait anxiety group, and FHR patterns after VAS showed mostly a type II response pattern. These findings suggest that stress in pregnant women with high trait anxiety may influence FHR patterns after VAS.

  9. 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.

  10. 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.

    2016-01-01

    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. PMID:26797626

  11. Oxidative stress parameters in unmedicated and treated bipolar subjects during initial manic episode: a possible role for lithium antioxidant effects.

    Science.gov (United States)

    Machado-Vieira, Rodrigo; Andreazza, Ana Cristina; Viale, Carlos Ivan; Zanatto, Vanessa; Cereser, Victor; da Silva Vargas, Rafael; Kapczinski, Flávio; Portela, Luiz V; Souza, Diogo O; Salvador, Mirian; Gentil, Valentim

    2007-06-21

    Studies have proposed the involvement of oxidative stress and neuronal energy dysfunctions in the pathophysiology of bipolar disorder (BD). This study evaluates plasma levels of the oxidative/energy metabolism markers, thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD), catalase (CAT), and neuron-specific enolase (NSE) during initial episodes of mania compared to controls in 75 subjects. Two groups of manic subjects (unmedicated n=30, and lithium-treated n=15) were age/gender matched with healthy controls (n=30). TBARS and antioxidant enzymes activity (SOD and CAT) were increased in unmedicated manic patients compared to controls. Conversely, plasma NSE levels were lower during mania than in the controls. In contrast, acute treatment with lithium showed a significant reduction in both SOD/CAT ratio and TBARS levels. These results suggest that initial manic episodes are associated with both increased oxidative stress parameters and activated antioxidant defenses, which may be related to dysfunctions on energy metabolism and neuroplasticity pathways. Antioxidant effects using lithium in mania were shown, and further studies are necessary to evaluate the potential role of these effects in the pathophysiology and therapeutics of BD.

  12. 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

    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...... 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.......-state thermal environments. Therefore, the first objective of the current paper was to compare a recently introduced unsteady-state model with previously used steady-state model using data obtained under both constant and transient temperature conditions. The second objective was to explore a relationship...

  13. 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.

  14. Heart Rate Variability as an Indicator of Chronic Stress Caused by Lameness in Dairy Cows.

    Science.gov (United States)

    Kovács, Levente; Kézér, Fruzsina Luca; Jurkovich, Viktor; Kulcsár-Huszenicza, Margit; Tőzsér, János

    2015-01-01

    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.

  15. Interrogation of the microstructure and residual stress of a nickel-base alloy subjected to surface severe plastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, A.L. [Departamento de Ingenieria Mecanica, Energetica y de los Materiales, Universidad de Extremadura, 06071 Badajoz (Spain); Tian, J.W. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN (United States); Villegas, J.C. [Intel Corporation, Chandler, AZ (United States); Shaw, L.L. [Department of Chemical, Materials and Biomolecular Engineering, University of Connecticut, Storrs, CT (United States)], E-mail: Leon.Shaw@Uconn.Edu; Liaw, P.K. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN (United States)

    2008-02-15

    A low stacking-fault energy nickel-base, single-phase, face-centered-cubic (fcc) alloy has been subjected to surface severe plastic deformation (S{sup 2}PD) to introduce nano-grains and grain size gradients to the surface region of the alloy. The simultaneous microstructural and stress state changes induced by S{sup 2}PD have been investigated via the X-ray diffraction (XRD) analysis that includes evaluation of annealing and deformation twins, deformation faults, in-plane lattice parameters and elastic strains of the crystal lattice, macroscopic residual in-plane stresses, crystallite sizes, internal strains, dislocation densities, and crystallographic texture as a function of the depth measured from the processed surface. Microstructural changes have also been characterized using optical and electron microscopy in order to corroborate the findings from the XRD analysis. The results from the XRD analysis are in excellent agreement with those derived from the microscopy analysis. This is the first systematic and comprehensive study using XRD to quantify depth-profile changes in a wide range of microstructural features and stress states in a fcc material resulting from the S{sup 2}PD process.

  16. Vegetarian diet improves insulin resistance and oxidative stress markers more than conventional diet in subjects with Type 2 diabetes.

    Science.gov (United States)

    Kahleova, H; Matoulek, M; Malinska, H; Oliyarnik, O; Kazdova, L; Neskudla, T; Skoch, A; Hajek, M; Hill, M; Kahle, M; Pelikanova, T

    2011-05-01

    The aim of this study was to compare the effects of calorie-restricted vegetarian and conventional diabetic diets alone and in combination with exercise on insulin resistance, visceral fat and oxidative stress markers in subjects with Type 2 diabetes. A 24-week, randomized, open, parallel design was used. Seventy-four patients with Type 2 diabetes were randomly assigned to either the experimental group (n = 37), which received a vegetarian diet, or the control group (n = 37), which received a conventional diabetic diet. Both diets were isocaloric, calorie restricted (-500 kcal/day). All meals during the study were provided. The second 12 weeks of the diet were combined with aerobic exercise. Participants were examined at baseline, 12 weeks and 24 weeks. Primary outcomes were: insulin sensitivity measured by hyperinsulinaemic isoglycaemic clamp; volume of visceral and subcutaneous fat measured by magnetic resonance imaging; and oxidative stress measured by thiobarbituric acid reactive substances. Analyses were by intention to treat. Forty-three per cent of participants in the experimental group and 5% of participants in the control group reduced diabetes medication (P vegetarian diet had greater capacity to improve insulin sensitivity compared with a conventional diabetic diet over 24 weeks. The greater loss of visceral fat and improvements in plasma concentrations of adipokines and oxidative stress markers with this diet may be responsible for the reduction of insulin resistance. The addition of exercise training further augmented the improved outcomes with the vegetarian diet. © 2011 The Authors. Diabetic Medicine © 2011 Diabetes UK.

  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. Self-rated stress is noncontributory to coronary artery disease in higher socioeconomic strata.

    Science.gov (United States)

    Kermott, Cindy A; Cha, Stephen S; Hagen, Philip T; Behrenbeck, Thomas

    2013-10-01

    Stress and its attendant psychosocial and lifestyle variables have been associated with coronary artery disease (CAD), yet the contribution of socioeconomic status (SES) has not been addressed. The aim of this study is to determine if stress assessment is associated with CAD independent of SES, and is incremental to the Framingham Score. The study group consisted of 325 executive patients undergoing comprehensive health assessment. Stress was assessed utilizing the validated "Self-Rated Stress" (SRS) instrument. Coronary artery calcification (CAC) served to assess the degree of atherosclerosis, a CAD equivalent and risk assessment tool. The relationship between SRS and CAC was assessed, with adjustment by potential confounders. CAC was modeled by a variety of cut points (>0, ≥5, ≥100, ≥200) for the test of trend across stress levels per Mantel-Haenszel chi-square (1 df) with nonsignificant P values of 0.9960, 0.5242, 0.1692, 0.3233, respectively. A logistic regression model with SRS as a categorically ranked and continuous variable to predict binary outcome of calcification yielded P values of 0.2366 and 0.9644; this relationship, further adjusted by age, fruit and vegetable consumption, exercise, and education, yielded no statistically significant association. No improvement of fit was observed for the established Framingham Score to CAC relation utilizing SRS. The study concluded that SRS did not play a role in early CAD when focusing on a population in higher socioeconomic strata, and SRS did not add predictive value beyond patient age or calculated Framingham risk. Future studies should focus on additional validated instruments of stress to differentiate between subtypes of stress for varying SES strata.

  19. Heart rate complexity: A novel approach to assessing cardiac stress reactivity.

    Science.gov (United States)

    Brindle, Ryan C; Ginty, Annie T; Phillips, Anna C; Fisher, James P; McIntyre, David; Carroll, Douglas

    2016-04-01

    Correlation dimension (D2), a measure of heart rate (HR) complexity, has been shown to decrease in response to acute mental stress and relate to adverse cardiovascular health. However, the relationship between stress-induced changes in D2 and HR has yet to be established. The present studies aimed to assess this relationship systematically while controlling for changes in respiration and autonomic activity. In Study 1 (N = 25) D2 decreased during stress and predicted HR reactivity even after adjusting for changes in respiration rate, and cardiac vagal tone. This result was replicated in Study 2 (N = 162) and extended by including a measure of cardiac sympathetic activity; correlation dimension remained an independent predictor of HR reactivity in a hierarchical linear model containing measures of cardiac parasympathetic and sympathetic activity and their interaction. These results suggest that correlation dimension may provide additional information regarding cardiac stress reactivity above that provided by traditional measures of cardiac autonomic function. © 2015 Society for Psychophysiological Research.

  20. 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.

  1. 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.

  2. Use of heart rate variability in monitoring stress and recovery in judo athletes.

    Science.gov (United States)

    Morales, José; Alamo, Juan M; García-Massó, Xavier; Buscà, Bernat; López, Jose L; Serra-Añó, Pilar; González, Luís-Millán

    2014-07-01

    The main objective of this study was to examine the effect of different judo training loads on heart rate variability (HRV) measurements, to determine if they can be used as valid indicators in monitoring stress and recovery in judo athletes. Fourteen male national-standard judo athletes were randomly divided into 2 groups, and each group followed a different type of training, namely, a high training load (HTL) and a moderate training load program (MTL). Data collection included HRV measurements, a Recovery Stress Questionnaire for athletes (RESTQ-SPORT), and strength measurements, 4 weeks before and after the training program. The HTL group had lower square root of the mean squared difference of successive RR intervals, very low frequency, high frequency, short-term variability, short-range scaling exponents, general recovery, sport-specific recovery, general stress, maximum strength, maximum power, and higher low/high frequency ratio at posttest compared with pretest (p ≤ 0.05). The HTL group showed lower short-range and long-range scaling exponents, general recovery, sport-specific recovery, and higher general stress than the MTL group in posttest measurements (p ≤ 0.05). In conclusion, judo athletes enrolled in an HTL program showed an imbalance of the autonomic nervous system with decreased vagal modulation, together with a decrease in strength parameters, higher markers for stress, and a lower perception of recovery.

  3. The Madrid Affective Database for Spanish (MADS): Ratings of Dominance, Familiarity, Subjective Age of Acquisition and Sensory Experience.

    Science.gov (United States)

    Hinojosa, José A; Rincón-Pérez, Irene; Romero-Ferreiro, M Verónica; Martínez-García, Natalia; Villalba-García, Cristina; Montoro, Pedro R; Pozo, Miguel A

    2016-01-01

    The current study presents ratings by 540 Spanish native speakers for dominance, familiarity, subjective age of acquisition (AoA), and sensory experience (SER) for the 875 Spanish words included in the Madrid Affective Database for Spanish (MADS). The norms can be downloaded as supplementary materials for this manuscript from https://figshare.com/s/8e7b445b729527262c88 These ratings may be of potential relevance to researches who are interested in characterizing the interplay between language and emotion. Additionally, with the aim of investigating how the affective features interact with the lexicosemantic properties of words, we performed correlational analyses between norms for familiarity, subjective AoA and SER, and scores for those affective variables which are currently included in the MADs. A distinct pattern of significant correlations with affective features was found for different lexicosemantic variables. These results show that familiarity, subjective AoA and SERs may have independent effects on the processing of emotional words. They also suggest that these psycholinguistic variables should be fully considered when formulating theoretical approaches to the processing of affective language.

  4. Protocol for an experimental investigation of the roles of oxytocin and social support in neuroendocrine, cardiovascular, and subjective responses to stress across age and gender

    Directory of Open Access Journals (Sweden)

    Block Jason

    2009-12-01

    Full Text Available Abstract Background Substantial empirical evidence has demonstrated that individuals who are socially isolated or have few positive social connections seem to age at a faster rate and have more chronic diseases. Oxytocin is a neurohypophyseal hormone hypothesized to coordinate both the causes and effects of positive social interactions, and may be involved in positive physiological adaptations such as buffering the deleterious effects of stress and promoting resilience. The proposed research will examine whether and how oxytocin influences responses to stress in humans and will consider effects in relation to those of social support. Methods/Design Experimental research will be used to determine whether exogenously administered oxytocin (intranasal influences psychological and physiological outcomes under conditions of stress across gender and age in adulthood. Hypotheses to be tested are: 1 Oxytocin ameliorates the deleterious neuroendocrine, cardiovascular, and subjective effects of stress; 2 Oxytocin and social support have similar and additive stress-buffering effects; 3 Oxytocin effects are stronger in women versus men; and 4 Oxytocin effects are similar across a range of adult ages. Hypotheses will be tested with a placebo-controlled, double-blind study using a sample of healthy men and women recruited from the community. Participants are randomly assigned to receive either oxytocin or placebo. They undergo a social stress manipulation with and without social support (randomly assigned, and outcome measures are obtained at multiple times during the procedure. Discussion Understanding the determinants of healthy aging is a major public health priority and identifying effective measures to prevent or delay the onset of chronic diseases is an important goal. Experimental research on oxytocin, social relationships, and health in adulthood will contribute to the scientific knowledge base for maximizing active life and health expectancy. At

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

    National Research Council Canada - National Science Library

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

    2012-01-01

    .... 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...

  6. 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.

  7. Self-Steem and changes in heart rate during laboratory-based stress.

    OpenAIRE

    Hughes, Brian M.

    2003-01-01

    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...

  8. Stress level in wild harbour porpoises (Phocoena phocoena) during satellite tagging measured by respiration, heart rate and cortisol

    DEFF Research Database (Denmark)

    Eskesen, Ida Grønborg; Teilmann, J.; Geertsen, B. M.

    2009-01-01

    During satellite tagging of harbour porpoises (Phocoena phocoena), heart rate, respiration rate and cortisol value were measured to evaluate stress effects during handling and tagging. Respiration rates were obtained using video recordings, heart rates were recorded and serum cortisol levels were...... and lowering it into the water seem to stabilize a stressed animal. Therefore, general precaution and individual judgement based on experience is essential when handling wild harbour porpoises....

  9. Underground verification of the large deflection performance of fibre reinforced shotcrete subjected to high stresses and convergence and to dynamic loading.

    CSIR Research Space (South Africa)

    Joughin, WC

    2002-04-01

    Full Text Available Committee Final Project Report Underground verification of the large deflection performance of fibre reinforced shotcrete subjected to high stresses and convergence and to dynamic loading W.C. Joughin, J.L. Human and P.J. Terbrugge Research agency...: Steffen, Robertson and Kirsten Project number: GAP 710 Date: April 2002 2 Executive summary The underground verification of the performance of fibre reinforced shotcrete, subject to high stresses, convergence and dynamic loading, was identified...

  10. 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...

  11. Headspace-Solid Phase Microextraction Approach for Dimethylsulfoniopropionate Quantification in Solanum lycopersicum Plants Subjected to Water Stress

    Science.gov (United States)

    Catola, Stefano; Kaidala Ganesha, Srikanta Dani; Calamai, Luca; Loreto, Francesco; Ranieri, Annamaria; Centritto, Mauro

    2016-01-01

    Dimethylsulfoniopropionate (DMSP) and dimethyl sulphide (DMS) are compounds found mainly in marine phytoplankton and in some halophytic plants. DMS is a globally important biogenic volatile in regulating of global sulfur cycle and planetary albedo, whereas DMSP is involved in the maintenance of plant-environment homeostasis. Plants emit minute amounts of DMS compared to marine phytoplankton and there is a need for hypersensitive analytic techniques to enable its quantification in plants. Solid Phase Micro Extraction from Head Space (HS-SPME) is a simple, rapid, solvent-free and cost-effective extraction mode, which can be easily hyphenated with GC-MS for the analysis of volatile organic compounds. Using tomato (Solanum lycopersicum) plants subjected to water stress as a model system, we standardized a sensitive and accurate protocol for detecting and quantifying DMSP pool sizes, and potential DMS emissions, in cryoextracted leaves. The method relies on the determination of DMS free and from DMSP pools before and after the alkaline hydrolysis via Headspace-Solid Phase Micro Extraction-Gas Chromatography-Mass Spectrometry (HS-SPME-GC-MS). We found a significant (2.5 time) increase of DMSP content in water-stressed leaves reflecting clear stress to the photosynthetic apparatus. We hypothesize that increased DMSP, and in turn DMS, in water-stressed leaves are produced by carbon sources other than direct photosynthesis, and function to protect plants either osmotically or as antioxidants. Finally, our results suggest that SPME is a powerful and suitable technique for the detection and quantification of biogenic gasses in trace amounts. PMID:27602039

  12. Effects of mindfulness based stress reduction therapy on subjective bother and neural connectivity in chronic tinnitus.

    Science.gov (United States)

    Roland, Lauren T; Lenze, Eric J; Hardin, Frances Mei; Kallogjeri, Dorina; Nicklaus, Joyce; Wineland, Andre M; Fendell, Ginny; Peelle, Jonathan E; Piccirillo, Jay F

    2015-05-01

    To evaluate the impact of a Mindfulness Based Stress Reduction (MBSR) program in patients with chronic bothersome tinnitus on the (1) severity of symptoms of tinnitus and (2) functional connectivity in neural attention networks. Open-label interventional pilot study. Outpatient academic medical center. A total of 13 adult participants with a median age of 55 years, suffering from bothersome tinnitus. An 8-week MBSR program was conducted by a trained MBSR instructor. The primary outcome measure was the difference in patient-reported tinnitus symptoms using the Tinnitus Handicap Index (THI) and Tinnitus Functional Index (TFI) between pre-intervention, post-MBSR, and 4-week post-MBSR assessments. Secondary outcomes included change in measurements of depression, anxiety, mindfulness, and cognitive abilities. Functional connectivity magnetic resonance imaging (MRI) was performed at pre- and post-MBSR intervention time points to serve as a neuroimaging biomarker of critical cortical networks. Scores on the THI and TFI showed statistically significant and clinically meaningful improvement over the course of the study with a median ΔTHI of -16 and median ΔTFI of -14.8 between baseline and 4-week follow-up scores. Except for depression, there was no significant change in any of the secondary outcome measures. Analysis of the resting state functional connectivity MRI (rs-fcMRI) data showed increased connectivity in the post-MBSR group in attention networks but not the default network. Participation in an MBSR program is associated with decreased severity in tinnitus symptoms and depression and connectivity changes in neural attention networks. MBSR is a promising treatment option for chronic bothersome tinnitus that is both noninvasive and inexpensive. © American Academy of Otolaryngology-Head and Neck Surgery Foundation 2015.

  13. Reversibility of stress-echo induced ST-segment depression by long-term oral n-3 PUFA supplementation in subjects with chest pain syndrome, normal wall motion at stress-echo and normal coronary angiogram

    Directory of Open Access Journals (Sweden)

    Ziacchi Vigilio

    2004-03-01

    Full Text Available Abstract Background Normal coronary arteries may coexist with abnormal coronary and systemic endothelial function in patients with chest pain. Recent work by the renowned Pisa echo-group elegantly suggests that isolated ST-segment depression during stress-echo (SE can be used as a marker of coronary endothelial dysfunction, in the absence of stress-inducible wall motion abnormalities and in the absence of angiographically-significant coronary artery disease (CAD. The long chain n-3 polyunsaturated fatty acids (PUFAs have been reported to possess several properties that may positively influence vascular function. The present study's hypothesis is that a 4 month-course of oral supplementation with n-3 PUFAs can reverse endothelial dysfunction. Methods Subjects were selected on the basis of the following criteria: 1 reported chest pain syndrome, 2 significant ST-segment depression during an otherwise normal SE, 3 absence of angiographically-significant CAD. Subjects underwent a 4-month course of oral supplementation with commercially available n-3 PUFA, 1 g once a day. Normalization of endothelial dysfunction was defined, at the end of the supplementation period, by the absence of significant ST-segment depression during repeat SE. We tested the aforementioned hypothesis in a very small series of consecutive subjects, with the intent to produce a hypothesis-generating study. Results Seven out of the total nine subjects enrolled (77.8% had normal ST-segment during repeat SE performed after the 4 month course of therapy. Conclusions A striking rate of reversion of SE-induced ST-segment depression after oral n-3 PUFAs suggests reversion of coronary endothelial dysfunction; nonetheless these data need to be validated in larger, placebo-controlled studies.

  14. Lithosphere strain rate and stress field orientations across the Alpine front

    Science.gov (United States)

    Houlie, Nicolas; Cardello, Luca

    2017-04-01

    In this study we test whether principal components of the strain rate and stress tensors align within Switzerland. We find that 1) the Alpine front is the most relevant tectonic boundary separating different domains of crustal stress / surface strain rates orientations and 2) orientations of T- axes (of moment tensor solutions) and long-term asthenosphere cumulative finite strain (from SKS shear wave splitting) are consistent. Additionally, we show that directions of principal components of both strain rate and stress tensors agree with orientations of shear wave splitting, implying that the Alpine arc is sheared by large-scale processe(s) taking place in the asthenosphere. At a more local scale, we find that seismic current activity and surface deformation are not in agreement in three regions (Basel, Swiss Jura and Ticino), possibly because of the low levels of deformation and seismicity. In the Basel area, deep seismicity exists while surface deformation is absent. In the Ticino and the Swiss Jura, where seismic activity is close to absent, surface deformation is detected at a level of 2x10-8/yr.

  15. Growth rate, protein:RNA ratio and stoichiometric homeostasis of submerged macrophytes under eutrophication stress

    Directory of Open Access Journals (Sweden)

    Xing W.

    2016-01-01

    Full Text Available Growth rate hypothesis (GRH and stoichiometric homeostasis of photoautotrophs have always been questioned. However, little is known about GRH and stoichiometric homeostasis of aquatic plants, especially submerged macrophytes. Therefore, we aim to test the GRH and explore stoichiometric homeostasis of four freshwater submerged macrophytes under eutrophication stress. At the single species level and the multi-species level, N:P ratios of Potamogeton maackianus, Myriophyllum spicatum, Vallisneria natans and Ceratophyllum demersum had no consistent trends with growth rates. However, protein:RNA ratios of P. maackianus, M. spicatum and V. natans all correlated negatively with growth rates, demonstrating GRH can apply to freshwater submerged macrophytes, even though they are threatening by eutrophication stress. Protein:RNA ratios positively correlated with N:P ratios in culture media and tissues in submerged macrophytes except in P. maackianus (30d, suggesting effects of varying N:P ratios in culture media on protein:RNA ratios are basically in concert with tissue N:P ratios under short-time eutrophication stress. Stoichiometric homeostasis coefficients (HN:P indicated submerged macrophytes have weak homeostasis. Stoichiometric homeostasis of V. natans was stronger than those of P. maackianus, M. spicatum and C. demersum. The differences in GRH and homeostasis of the four submerged macrophytes may be due to species traits.

  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. Projective drawings for assessing stress among subjects with medical symptoms compatible with sick building syndrome, and validation of a modified version of the Stress Load Index from the Drawing Personality Profile: a pilot study.

    Science.gov (United States)

    Runeson, Roma; Wahlstedt, Kurt; Norbäck, Dan

    2007-02-01

    It was hypothesized that subjects with medical symptoms would show more signs of stress in projective drawings. A Stress Load Index, including five signs of stress in drawings, was evaluated. A questionnaire with an instruction to draw "a person in the rain" was sent to a cohort of 195 subjects, and the drawings were analysed blindly for eight stress items. Men had a higher index than women (p sick building syndrome symptoms (p < .05). In conclusion, a nonverbal projective drawing test detected sex differences which represent directions opposite to those with verbal methods. These need empirical assessment.

  18. Older age is associated with greater central aortic blood pressure following the exercise stress test in subjects with similar brachial systolic blood pressure.

    Science.gov (United States)

    Kobayashi, Masatake; Oshima, Kazutaka; Iwasaki, Yoichi; Kumai, Yuto; Avolio, Alberto; Yamashina, Akira; Takazawa, Kenji

    2016-08-01

    Brachial systolic pressure (BSP) is often monitored during exercise by the stress test; however, central systolic pressure (CSP) is thought to be a more direct measure of cardiovascular events. Although some studies reported that exercise and aging may play roles in changes of both BSP and CSP, the relationship between BSP and CSP with age following the exercise stress test remains unclear. The aim of this study was to evaluate the effect of age on the relationship between BSP and CSP measured after exercise. Ninety-six subjects underwent the diagnostic treadmill exercise stress test, and we retrospectively divided them into the following 3 groups by age: the younger age group (43 ± 4 years), middle age group (58 ± 4 years), and older age group (70 ± 4 years). Subjects exercised according to the Bruce protocol, to achieve 85 % of their age-predicted maximum heart rate or until the appearance of exercise-associated symptoms. BSP, CSP, and pulse rate (PR) were measured using a HEM-9000AI (Omron Healthcare, Japan) at rest and after exercise. BSP, CSP, and PR at rest were not significantly different among the 3 groups (p = 0.92, 0.21, and 0.99, respectively). BSP and PR immediately after exercise were not significantly different among the groups (p = 0.70 and 0.38, respectively). However, CSP immediately after exercise was 144 ± 18 mmHg (younger age), 149 ± 17 mmHg (middle age), and 158 ± 19 mmHg (older age). CSP in the older age group was significantly higher than that in the younger age group (p age groups after exercise, CSP was higher in the older age group. Therefore, older subjects have a higher CSP after exercise, which is not readily assessed by conventional measurements of BSP.

  19. The COFU3 Study. Improvement in cognitive function, attention, mental performance with Pycnogenol® in healthy subjects (55-70) with high oxidative stress.

    Science.gov (United States)

    Belcaro, G; Dugall, M; Ippolito, E; Hu, S; Saggino, A; Feragalli, B

    2015-12-01

    This 12-month product registry study evaluated the effects of supplementation with French pine bark extract (Pycnogenol(®)) on cognitive function, attention, and mental performance in healthy subjects with high oxidative stress. Healthy subjects (age range 55-70) were screened - within a cardiovascular screening program - for oxidative stress. Out of 150 subjects, high oxidative stress was present in 44; the use of the supplement Pycnogenol(®) was suggested (100 mg/day). These subjects decided to use Pycnogenol(®) and accepted to be evaluated by assessing cognitive functions. A group of subjects with comparable oxidative stress was followed as a reference. IQ Code (Informant Questionnaire on Cognitive Decline in the Elderly), daily tasks, cognitive function, oxidative stress and the short Blessed tests (SBT) were used (in defined scales) to evaluate cognitive functions (COFU). As for the IQ Code, at 12 months there was a significantlty total lower score in Pycnogenol(®) patients and also a lower value (PPycnogenol(®) (-28.07%; PPycnogenol(®) group (PPycnogenol(®) were optimal with >97% of the doses of the supplement correctly used. No side effects were observed, recorded or described. Pycnogenol(®) supplementation for 12 months appears to improve cognitive function and oxidative stress in normal subjects between 55 and 70 years of age.

  20. 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

  1. Target heart rate to determine the normal value of coronary flow reserve during dobutamine stress echocardiography

    Directory of Open Access Journals (Sweden)

    Rousse Maria G

    2011-04-01

    Full Text Available Abstract Background The determination of coronary flow reserve (CFR is an essential concept at the moment of decision-making in ischemic heart disease. There are several direct and indirect tests to evaluate this parameter. In this sense, dobutamine stress echocardiography is one of the pharmacological method most commonly used worldwide. It has been previously demonstrated that CFR can be determined by this technique. Despite our wide experience with dobutamine stress echocardiography, we ignored the necessary heart rate to consider sufficient the test for the analysis of CFR. For this reason, our main goal was to determine the velocity of coronary flow in each stage of dobutamine stress echocardiography and the heart rate value necessary to double the baseline values of coronary flow velocity in the territory of the left anterior descending (LAD coronary artery. Methods A total of 33 consecutive patients were analyzed. The patients included had low risk for coronary artery disease. All the participants underwent dobutamine stress echocardiography and coronary artery flow velocity was evaluated in the distal segment of LAD coronary artery using transthoracic color-Doppler echocardiography. Results The feasibility of determining CFR in the territory of the LAD during dobutamine stress echocardiography was high: 31/33 patients (94%. Mean CFR was 2.67 at de end of dobutamine test. There was an excellent concordance between delta HR (difference between baseline HR and maximum HR and the increase in the CFR (correlation coefficient 0.84. In this sense, we found that when HR increased by 50 beats, CFR was ≥ 2 (CI 93-99.2%. In addition, 96.4% of patients reached a CFR ≥ 2 (IC 91.1 - 99% at 75% of their predicted maximum heart rate. Conclusions We found that the feasibility of dobutamine stress echocardiography to determine CFR in the territory of the LAD coronary artery was high. In this study, it was necessary to achieve a difference of 50 bpm

  2. A real-time phenotyping framework using machine learning for plant stress severity rating in soybean.

    Science.gov (United States)

    Naik, Hsiang Sing; Zhang, Jiaoping; Lofquist, Alec; Assefa, Teshale; Sarkar, Soumik; Ackerman, David; Singh, Arti; Singh, Asheesh K; Ganapathysubramanian, Baskar

    2017-01-01

    Phenotyping is a critical component of plant research. Accurate and precise trait collection, when integrated with genetic tools, can greatly accelerate the rate of genetic gain in crop improvement. However, efficient and automatic phenotyping of traits across large populations is a challenge; which is further exacerbated by the necessity of sampling multiple environments and growing replicated trials. A promising approach is to leverage current advances in imaging technology, data analytics and machine learning to enable automated and fast phenotyping and subsequent decision support. In this context, the workflow for phenotyping (image capture → data storage and curation → trait extraction → machine learning/classification → models/apps for decision support) has to be carefully designed and efficiently executed to minimize resource usage and maximize utility. We illustrate such an end-to-end phenotyping workflow for the case of plant stress severity phenotyping in soybean, with a specific focus on the rapid and automatic assessment of iron deficiency chlorosis (IDC) severity on thousands of field plots. We showcase this analytics framework by extracting IDC features from a set of ~4500 unique canopies representing a diverse germplasm base that have different levels of IDC, and subsequently training a variety of classification models to predict plant stress severity. The best classifier is then deployed as a smartphone app for rapid and real time severity rating in the field. We investigated 10 different classification approaches, with the best classifier being a hierarchical classifier with a mean per-class accuracy of ~96%. We construct a phenotypically meaningful 'population canopy graph', connecting the automatically extracted canopy trait features with plant stress severity rating. We incorporated this image capture → image processing → classification workflow into a smartphone app that enables automated real-time evaluation of IDC

  3. Crash and traffic violation rates before and after licensure for novice California drivers subject to different driver licensing requirements.

    Science.gov (United States)

    Chapman, Eric A; Masten, Scott V; Browning, Kelly K

    2014-09-01

    How do crash and traffic violation rates for novice 16-17-year-old drivers change over the months before and after licensure under a graduated driver licensing (GDL) program relative to those for older novices who are not subject to GDL? Plots and Poisson regression comparing overall rates and subtypes of crashes and traffic violations among California novice drivers ages 16 to 35 years over time before and after unsupervised licensure. Majorities of 16-year-olds (57%) and 17-year-olds (73%) actually hold their learner permits longer than the required 6 months; majorities (67%-81%) of age 18 or older novices hold their learner permits less than 6 months. Crash rates of novice 16- and 17-year-olds-as well as most other age groups-are highest almost immediately after they are licensed to drive unsupervised, after which their rates decline quickly during their first year of licensure and at a slower rate for the second and third years. Novice 16- and 17-year-olds' traffic violation rates reach their zenith long after their total crash rates peak and decline, whereas violation rates for older novices peak during their first year of licensure. Over 70% of 16- and 17-year-old novices are crash-free for the first 3 years of licensure. While novice 16- and 17-year-olds' highest crash rates occur almost immediately after they are licensed, their peak traffic violation rates are delayed until around the time they turn age 18. Both pre-licensure crash rates and post-licensure crash peaks were more pronounced for some older age groups of novices than was the case for 16-17-year-olds. Extending learner permit holding periods for 16-17-year-old novices appears consistent with their actual behavior; requiring older novices-particularly those ages 18 to 20-to hold permits for minimum periods may reduce their initial crash rates. Copyright © 2014 National Safety Council and Elsevier Ltd. All rights reserved.

  4. Changes in pulse rate, respiratory rate, blood oxygenation, perfusion index, skin conductance, and their variability induced during and after grounding human subjects for 40 minutes.

    Science.gov (United States)

    Chevalier, Gaetan

    2010-01-01

    Previous studies have shown that grounding produces quantifiable physiologic changes. This study was set up to reproduce and expand earlier electrophysiologic and physiologic parameters measured immediately after grounding with improved methodology and state-of-the-art equipment. A multiparameter double-blind experiment was conducted with 14 men and 14 women (age range: 18-80) in relatively good health. Subjects were screened for health problems using a commonly used health questionnaire. They were seated in a comfortable recliner and measured during 2-hour grounding sessions, leaving time for signals to stabilize before, during, and after grounding (40 minutes for each period). Sham 2-hour grounding sessions were also recorded with the same subjects as controls. This report presents results for 5 of the 18 parameters measured. The parameters reported here are: skin conductance (SC), blood oxygenation (BO), respiratory rate (RR), pulse rate (PR), and perfusion index (PI). This study was performed in a rented facility in Encinitas, California. The facility was chosen in a quiet area for its very low electromagnetic noise. For each session, statistical analyses were performed on four 10-minute segments: before and after grounding (sham grounding for control session) and before and after ungrounding (sham ungrounding). There was an immediate decrease in SC at grounding and an immediate increase at ungrounding on all subjects. RR increased during grounding, and the effect lasted after ungrounding. RR variance increased immediately after grounding then decreased. BO variance decreased during grounding, followed by a dramatic increase after ungrounding. PR and PI variances increased toward the end of the grounding period, and this change persisted after ungrounding. These results warrant further research to determine how grounding affects the body. Grounding could become important for relaxation, health maintenance and disease prevention.

  5. Resting Metabolic Rate Does Not Change in Response to Different Types of Training in Subjects with Type 2 Diabetes

    Directory of Open Access Journals (Sweden)

    Kristian Karstoft

    2017-06-01

    Full Text Available Background and objectivesAmbiguous results have been reported regarding the effects of training on resting metabolic rate (RMR, and the importance of training type and intensity is unclear. Moreover, studies in subjects with type 2 diabetes (T2D are sparse. In this study, we evaluated the effects of interval and continuous training on RMR in subjects with T2D. Furthermore, we explored the determinants for training-induced alterations in RMR.MethodsData from two studies, both including T2D subjects, were encompassed in this manuscript. Study 1 was a randomized, crossover study where subjects (n = 14 completed three, 2-week interventions [control, continuous walking training (CWT, interval-walking training (IWT] separated by washout periods. Training included 10 supervised treadmill sessions, 60 min/session. CWT was performed at moderate walking speed [aiming for 73% of walking peak oxygen uptake (VO2peak], while IWT was performed as alternating 3-min repetitions at slow (54% VO2peak and fast (89% VO2peak walking speed. Study 2 was a single-arm training intervention study where subjects (n = 23 were prescribed 12 weeks of free-living IWT (at least 3 sessions/week, 30 min/session. Before and after interventions, RMR, physical fitness, body composition, and glycemic control parameters were assessed.ResultsNo overall intervention-induced changes in RMR were seen across the studies, but considerable inter-individual differences in RMR changes were seen in Study 2. At baseline, total body mass (TBM, fat-free mass (FFM, and fat mass were all associated with RMR. Changes in RMR were associated with changes in TBM and fat mass, and subjects who decreased body mass and fat mass also decreased their RMR. No associations were seen between changes in physical fitness, glycemic control, or FFM and changes in RMR.ConclusionNeither short-term continuous or interval-type training, nor longer term interval training affects RMR in subjects with T2D

  6. Resting Metabolic Rate Does Not Change in Response to Different Types of Training in Subjects with Type 2 Diabetes.

    Science.gov (United States)

    Karstoft, Kristian; Brinkløv, Cecilie Fau; Thorsen, Ida Kær; Nielsen, Jens Steen; Ried-Larsen, Mathias

    2017-01-01

    Ambiguous results have been reported regarding the effects of training on resting metabolic rate (RMR), and the importance of training type and intensity is unclear. Moreover, studies in subjects with type 2 diabetes (T2D) are sparse. In this study, we evaluated the effects of interval and continuous training on RMR in subjects with T2D. Furthermore, we explored the determinants for training-induced alterations in RMR. Data from two studies, both including T2D subjects, were encompassed in this manuscript. Study 1 was a randomized, crossover study where subjects (n = 14) completed three, 2-week interventions [control, continuous walking training (CWT), interval-walking training (IWT)] separated by washout periods. Training included 10 supervised treadmill sessions, 60 min/session. CWT was performed at moderate walking speed [aiming for 73% of walking peak oxygen uptake (VO2peak)], while IWT was performed as alternating 3-min repetitions at slow (54% VO2peak) and fast (89% VO2peak) walking speed. Study 2 was a single-arm training intervention study where subjects (n = 23) were prescribed 12 weeks of free-living IWT (at least 3 sessions/week, 30 min/session). Before and after interventions, RMR, physical fitness, body composition, and glycemic control parameters were assessed. No overall intervention-induced changes in RMR were seen across the studies, but considerable inter-individual differences in RMR changes were seen in Study 2. At baseline, total body mass (TBM), fat-free mass (FFM), and fat mass were all associated with RMR. Changes in RMR were associated with changes in TBM and fat mass, and subjects who decreased body mass and fat mass also decreased their RMR. No associations were seen between changes in physical fitness, glycemic control, or FFM and changes in RMR. Neither short-term continuous or interval-type training, nor longer term interval training affects RMR in subjects with T2D when no overall changes in body composition are seen

  7. 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.

  8. 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.

  9. Relationship between heart rate variability, blood pressure and arterial wall properties during air and oxygen breathing in healthy subjects.

    Science.gov (United States)

    Graff, Beata; Szyndler, Anna; Czechowicz, Krzysztof; Kucharska, Wiesława; Graff, Grzegorz; Boutouyrie, Pierre; Laurent, Stephane; Narkiewicz, Krzysztof

    2013-11-01

    Previous studies reported that normobaric hyperoxia influences heart rate, arterial pressure, cardiac output and systemic vascular resistance, but the mechanisms underlying these changes are still not fully understood. Several factors are considered including degeneration of endothelium-derived nitric oxide by reactive oxygen species, the impact of oxygen-free radicals on tissues and alterations of autonomic nervous system function. Recently, new devices for the detailed non-invasive assessment of large and small arteries have been developed. Therefore, the aim of our study was to assess heart rate variability (HRV) as a potential indicator of autonomic balance and its relation to blood pressure and vascular properties during medical air (MAB) and 100% oxygen breathing (OXB) in healthy volunteers. In 12 healthy subjects we assessed heart rate and blood pressure variability, baroreflex sensitivity, respiratory frequency, common carotid artery diameter and its wall distensibility, as well as changes in the digital artery pulse waveform, stroke index and systemic vascular resistance during MAB and OXB. Mean and systolic blood pressure have increased significantly while digital pulse amplitude and carotid artery diameter were significantly lower during hyperoxia. Heart rate variability measures did not differ during MAB and OXB. However, the correlations between spectral HRV components and those hemodynamic parameters which have changed due to hyperoxia varied substantially during MAB (correlated significantly) and OXB (no significant correlations were noted). Our findings suggest that autonomic nervous system might not be the main mediator of the cardiovascular changes during 100% oxygen breathing in healthy subjects. It seems that the direct vascular responses are initial consequences of hyperoxia and other cardiovascular parameter alterations are secondary to them. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. An explanation for catastrophic failures of GaN-based vertical structure LEDs subjected to thermoelectric stressing

    Science.gov (United States)

    Liu, Lilin; Yin, Luqiao; Teng, Dongdong; Zhang, Jianhua; Ma, Xincan; Wang, Gang

    2015-08-01

    Both accelerated life tests and engineering practices present a common behavior: LED products may encounter catastrophic failure under thermo-electric co-stressing. The present work proposes that the applied thermoelectric stresses themselves are not necessary conditions but pre-conditions for LED breakdown. The deformation and sliding of the metal lines on n-GaN under thermoelectric co-stressing cause electrodes to become dilapidated. Such dilapidated electrodes with rough edges will help to generate localized high electrical fields. The catastrophic failure occurs during the de-trapping process of space charges in and around threading dislocations when the applied electric field is removed and short circuits form between the charged dislocation cores and the tips of the dilapidated electrodes. A phenomenological relationship is given to describe the interactions between temperatures and applied electric currents on the diffusion-flux-accommodated sliding and deformation of patterned metal electrodes on vertical LEDs. Such a law is coincident with the practical trend of LED failure rates observed in accelerated life tests and engineering applications.

  11. Measuring the subjective: revisiting the psychometric properties of three rating scales that assess the acute effects of hallucinogens.

    Science.gov (United States)

    Bouso, José Carlos; Pedrero-Pérez, Eduardo José; Gandy, Sam; Alcázar-Córcoles, Miguel Ángel

    2016-09-01

    In the present study we explored the psychometric properties of three widely used questionnaires to assess the subjective effects of hallucinogens: the Hallucinogen Rating Scale (HRS), the Mystical Experience Questionnaire (MEQ), and the Addiction Research Center Inventory (ARCI). These three questionnaires were administered to a sample of 158 subjects (100 men) after taking ayahuasca, a hallucinogen whose main active component is N,N-dimethyltryptamine (DMT). A confirmatory factorial study was conducted to check the adjustment of previous data obtained via theoretical proposals. When this was not possible, we used an exploratory factor analysis without restrictions, based on tetrachoric and polychoric matrices and correlations. Our results sparsely match the theoretical proposals of the authors, perhaps because previous studies have not always employed psychometric methods appropriate to the data obtained. However, these data should be considered preliminary, pending larger samples to confirm or reject the proposed structures obtained. It is crucial that instruments of sufficiently precise measurement are utilized to make sense of the information obtained in the study of the subjective effects of psychedelic drugs. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  12. Heart Rate Dynamics and their Relation with the Cyclic Alternating Pattern of Sleep in Normal Subjects and NFLE Patients

    Science.gov (United States)

    González, Jose S.; Dorantes, Guadalupe; Alba, Alfonso; Méndez, Martin O.; Camacho, Sergio; Luna-Rivera, Martin; Parrino, Liborio; Riccardi, Silvia; Terzano, Mario G.; Milioli, Giulia

    The aim of this work is to study the behavior of the autonomic system through variations in the heart rate (HR) during the Cyclic Alternating Pattern (CAP) which is formed by A-phases. The analysis was carried out in 10 healthy subjects and 10 patients with Nocturnal Front Lobe Epilepsy (NFLE) that underwent one whole night of polysomnographic recordings. In order to assess the relation of A-phases with the cardiovascular system, two time domain features were computed: the amplitude reduction and time delay of the minimum of the R-R intervals with respect to A-phases onset. In addition, the same process was performed over randomly chosen R-R interval segments during the NREM sleep for baseline comparisons. A non-parametric bootstrap procedure was used to test differences of the kurtosis values of two populations. The results suggest that the onset of the A-phases is correlated with a significant increase of the HR that peaks at around 4s after the A-phase onset, independently of the A-phase subtype and sleep time for both healthy subjects and NFLE patients. Furthermore, the behavior of the reduction in the R-R intervals during the A-phases was significantly different for NFLE patients with respect to control subjects.

  13. Effects of music therapy on subjective sensations and heart rate variability in treated cancer survivors: a pilot study.

    Science.gov (United States)

    Chuang, Chih-Yuan; Han, Wei-Ru; Li, Pei-Chun; Young, Shuenn-Tsong

    2010-10-01

    Data on the effects of music therapy on subjective sensations and the physiological parameters of heart rate variability (HRV) in treated cancer survivors are scarce. The aim of this study was to determine whether or not music therapy affects the sensations of fatigue, comfort, and relaxation in cancer survivors, and affects the activities of the sympathetic and parasympathetic nervous systems as indicated by HRV parameters. Twenty-three patients aged 30-67 years and with cancer that had been treated at least 6 months previously received music therapy for about 2h, which included singing, listening to music, learning the recorder, and performing music. Subjective sensations and electrocardiogram were recorded before and after the music therapy. The low-frequency and high-frequency components of HRV were assessed by the frequency analysis of sequential R wave to R wave intervals of electrocardiogram obtained from 5-min recordings. Subjective sensations were quantitatively assessed using a visual analog mood scale. Two hours of music therapy significantly increased relaxation sensations and significantly decreased fatigue sensation in treated cancer survivors. Moreover, the HRV parameters showed that parasympathetic nervous system activity increased and sympathetic nervous system activity decreased. This study provides preliminary evidence that music therapy may be clinically useful for promoting relaxation sensation and increasing parasympathetic nervous system activity in treated cancer survivors. Copyright © 2010. Published by Elsevier Ltd.

  14. 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.

  15. Internal stress-induced melting below melting temperature at high-rate laser heating

    Science.gov (United States)

    Hwang, Yong Seok; Levitas, Valery I.

    2014-06-01

    In this Letter, continuum thermodynamic and phase field approaches (PFAs) predicted internal stress-induced reduction in melting temperature for laser-irradiated heating of a nanolayer. Internal stresses appear due to thermal strain under constrained conditions and completely relax during melting, producing an additional thermodynamic driving force for melting. Thermodynamic melting temperature for Al reduces from 933.67 K for a stress-free condition down to 898.1 K for uniaxial strain and to 920.8 K for plane strain. Our PFA simulations demonstrated barrierless surface-induced melt nucleation below these temperatures and propagation of two solid-melt interfaces toward each other at the temperatures very close to the corresponding predicted thermodynamic equilibrium temperatures for the heating rate Q ≤1.51×1010K/s. At higher heating rates, kinetic superheating competes with a reduction in melting temperature and melting under uniaxial strain occurs at 902.1 K for Q = 1.51 × 1011 K/s and 936.9 K for Q = 1.46 × 1012 K/s.

  16. Internal stress-induced melting below melting temperature at high-rate laser heating

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Yong Seok, E-mail: yshwang@iastate.edu [Department of Aerospace Engineering, Iowa State University, Ames, Iowa 50011 (United States); Levitas, Valery I., E-mail: vlevitas@iastate.edu [Departments of Aerospace Engineering, Mechanical Engineering, and Material Science and Engineering, Iowa State University, Ames, Iowa 50011 (United States)

    2014-06-30

    In this Letter, continuum thermodynamic and phase field approaches (PFAs) predicted internal stress-induced reduction in melting temperature for laser-irradiated heating of a nanolayer. Internal stresses appear due to thermal strain under constrained conditions and completely relax during melting, producing an additional thermodynamic driving force for melting. Thermodynamic melting temperature for Al reduces from 933.67 K for a stress-free condition down to 898.1 K for uniaxial strain and to 920.8 K for plane strain. Our PFA simulations demonstrated barrierless surface-induced melt nucleation below these temperatures and propagation of two solid-melt interfaces toward each other at the temperatures very close to the corresponding predicted thermodynamic equilibrium temperatures for the heating rate Q≤1.51×10{sup 10}K/s. At higher heating rates, kinetic superheating competes with a reduction in melting temperature and melting under uniaxial strain occurs at 902.1 K for Q = 1.51 × 10{sup 11 }K/s and 936.9 K for Q = 1.46 × 10{sup 12 }K/s.

  17. Healing ligaments have shorter lifetime and greater strain rate during fatigue than creep at functional stresses.

    Science.gov (United States)

    Thornton, Gail M; Bailey, Soraya J

    2013-09-01

    Healing ligaments have compromised strength, which makes them susceptible to damage during daily activities at normal functional stresses. Daily activities expose ligaments to cyclic (fatigue) and static (creep) loading. A gap injury was created in the midsubstance of both hindlimb medial collateral ligaments of 40 female 1-year-old New Zealand White rabbits. After a 14-week healing interval, medial collateral ligament gap scars were exposed to long-term fatigue and creep loading over a range of functional force/stress levels. Lifetime and strain behavior were compared during fatigue and creep. The contribution of time-dependent mechanisms to fatigue lifetime was modeled using creep data. Fatigue-loaded healing ligaments had shorter lifetime, greater steady-state strain rate and greater increase in strain at 0.8 h than creep-loaded healing ligaments. The actual fatigue lifetime was less than the predicted fatigue lifetime which was derived from time-dependent damage alone, indicating an important role for cycle-dependent damage mechanisms in healing ligaments during fatigue loading. Cyclic loading decreased lifetime and increased strain rate and strain prior to rupture compared to static loading in healing ligaments. These findings suggest that, after a ligament injury, more care should be taken when exercises result in cyclic loading rather than static loading of the healing ligament even at functional stresses.

  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

    2015-12-01

    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 (signal detection rate, SDR and recognition reaction time, RRT) as measures of CL. In phase 1 of the study, novice learners and expert surgeons attempted a visual-monitoring task under two conditions: single-task (monitoring a virtual patient's heart-rate) and dual-task (tying surgical knots on a bench-top simulator while monitoring the virtual patient's heart-rate). Novices demonstrated higher mental effort and inferior secondary-task performance on the dual-task compared to experts (RRT 1.76 vs. 0.73, p = 0.012; SDR 0.27 vs. 0.97, p instructional design research are discussed.

  19. The Mediating Roles of Perceived Stress and Health Behaviors in the Relation between Objective, Subjective, and Neighborhood Socioeconomic Status and Perceived Health

    Science.gov (United States)

    Senn, Theresa E.; Walsh, Jennifer L.; Carey, Michael P.

    2014-01-01

    Background Objective, subjective, and neighborhood socioeconomic status (SES) are associated with perceived health, morbidity, and mortality. Purpose We investigated whether perceived stress and health behaviors mediated the relation between the three types of SES and perceived health. Methods Participants (N = 508) attending a public clinic completed a computerized survey assessing objective SES (income, education, employment); health behaviors; perceived stress; and perceived health. They also indicated their social standing relative to others (subjective SES) and provided their current address to determine neighborhood SES. Results In a structural equation model including all three SES types, lower objective and subjective SES were related to poorer perceived health. When mediators were included in the model, there were significant indirect effects of: (a) SES on health through stress; and (b) SES on health through stress and health compromising behaviors. Conclusions Interventions to reduce the impact of stressors could improve the health of socioeconomically disadvantaged individuals. PMID:24648016

  20. 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.

  1. Influence of L-Carnitine on fitness and oxidative stress parameters in Trotter Horses subjected to Laval’s test

    Directory of Open Access Journals (Sweden)

    Adalberto Falaschini

    2010-01-01

    Full Text Available In the last few years, in addition to grain, the high energy requirements of racehorses have been met with dietary supplementsof vegetable oil, which may, however, represent an easily oxidisable substrate. Carnitine can be used to improvelipid metabolism. We evaluated the changes in performance and oxidative stress parameters measured in 4 trottersreceiving a diet containing soybean oil and L-Carnitine and subjected to two Standardized Exercise Tests (SET accordingto Laval’s protocol (3 hits at increasing speed at an interval of 30 days. Blood samples were taken at rest, just aftereach of the three hits, and at 10, 20 and 40 min after each test to determine lactic acid, glucose, Non-Esterified FattyAcid (NEFA, β-hydroxybutyrate, Reactive Oxygen metabolites (ROMs, Glutathione Peroxidase (GSH-Px, and SuperoxideDismutase (SOD. L-Carnitine influenced ROMs and SOD and resulted in a reduction in the oxidative stress parameters.Some indices of the fitness status also improved.

  2. Psychopathological symptoms, defense mechanisms and time perspectives among subjects with alcohol dependence (AD) presenting different patterns of coping with stress.

    Science.gov (United States)

    Iwanicka, Katarzyna; Gerhant, Aneta; Olajossy, Marcin

    2017-01-01

    The problem of coping with stress is an important one in the context of development and persistence of alcohol dependence. In the literature to date very little attention has been paid to coping patterns construed as a configuration of specific coping styles, particularly as regards the functioning of addicted individuals. The aim of the study was to verify whether individuals with alcohol dependence characterized by different coping patterns differ with respect to the severity of psychopathological symptoms, defense mechanisms and time perspectives. Participants were given a battery of psychological tests-Coping Inventory for Stresfull Situations (CISS), Defense Style Questionnaire (DSQ 40), Syndrom Checklist (SCL-90) and Short Zimbardo Time Perspective Inventory (SZPTI-PL). The sample comprised 112 individuals with alcohol dependence, aged 20 to 63 years old, the average age was 37.86; 78 percent were men. There were identified three sub-groups of individuals characterized by a distinctive patterns of coping with stress -"emotional-avoidant", "task oriented" and a "mixed one". Individuals with the predominant emotional-avoidant coping pattern are characterized by significantly higher severity of psychopathological symptoms, less mature defense mechanisms and past time perspectives. Subjects reliant on task-oriented coping pattern were characterized by the highest level of adaptation and the most constructive way of functioning in the face of difficulties. It is worth regarding the examination of patterns of coping as an indispensable element of collecting medical history from alcohol dependent individuals.

  3. 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.

  4. Risky business: trauma exposure and rate of posttraumatic stress disorder in African American children and adolescents.

    Science.gov (United States)

    Hunt, Kristin L; Martens, Patricia M; Belcher, Harolyn M E

    2011-06-01

    Demographics, parental risk factors, and experiencing interpersonal trauma (domestic violence, community violence, and physical and sexual abuse) are related to childhood posttraumatic stress disorder (PTSD). Little is known about these factors and the risk of PTSD in African American children. This study examined associations between PTSD symptoms and gender, age, parent mental illness, parent substance abuse, and interpersonal trauma in African American children. Participants were 257 children and adolescents, ages 8-17 years (M = 11.7, SD = 2.5), who received outpatient mental health treatment. Being female and witnessing domestic violence was associated with more PTSD symptoms. Exposure to community violence and physical abuse increased the odds of clinically significant PTSD symptomatology by more than 2 times. The rate of PTSD (16%) was lower in the current study than in other same-age study populations (25%-40%). Risk factors and identification strategies for PTSD are discussed. Copyright © 2011 International Society for Traumatic Stress Studies.

  5. Decrease in heart rate variability response to task is related to anxiety and depressiveness in normal subjects.

    Science.gov (United States)

    Shinba, Toshikazu; Kariya, Nobutoshi; Matsui, Yasue; Ozawa, Nobuyuki; Matsuda, Yoshiki; Yamamoto, Ken-Ichi

    2008-10-01

    Previous studies have shown that heart rate variability (HRV) measurement is useful in investigating the pathophysiology of various psychiatric disorders. The present study further examined its usefulness in evaluating the mental health of normal subjects with respect to anxiety and depressiveness. Heart rate (HR) and HRV were measured tonometrically at the wrist in 43 normal subjects not only in the resting condition but also during a task (random number generation) to assess the responsiveness. For HRV measurement, high-frequency (HF; 0.15-0.4 Hz) and low-frequency (LF; 0.04-0.15 Hz) components of HRV were obtained using MemCalc, a time series analysis technique that combines a non-linear least square method with maximum entropy method. For psychological evaluation of anxiety and depressiveness, two self-report questionnaires were used: State-Trait Anxiety Inventory (STAI) and Self-Rating Depression Scale (SDS). No significant relation was observed between HR and HRV indices, and the psychological scores both in the resting and task conditions. By task application, HF decreased, and LF/HF and HR increased, and significant correlation with psychological scores was found in the responsiveness to task measured by the ratio of HRV and HR indices during the task to that at rest (task/rest ratio). A positive relationship was found between task/rest ratio for HF, and STAI and SDS scores. Task/rest ratio of HR was negatively correlated with STAI-state score. Decreased HRV response to task application is related to anxiety and depressiveness. Decreased autonomic responsiveness could serve as a sign of psychological dysfunction.

  6. 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

  7. Moisture, anisotropy, stress state, and strain rate effects on bighorn sheep horn keratin mechanical properties.

    Science.gov (United States)

    Johnson, K L; Trim, M W; Francis, D K; Whittington, W R; Miller, J A; Bennett, C E; Horstemeyer, M F

    2017-01-15

    This paper investigates the effects of moisture, anisotropy, stress state, and strain rate on the mechanical properties of the bighorn sheep (Ovis Canadensis) horn keratin. The horns consist of fibrous keratin tubules extending along the length of the horn and are contained within an amorphous keratin matrix. Samples were tested in the rehydrated (35wt% water) and ambient dry (10wt% water) conditions along the longitudinal and radial directions under tension and compression. Increased moisture content was found to increase ductility and decrease strength, as well as alter the stress state dependent nature of the material. The horn keratin demonstrates a significant strain rate dependence in both tension and compression, and also showed increased energy absorption in the hydrated condition at high strain rates when compared to quasi-static data, with increases of 114% in tension and 192% in compression. Compressive failure occurred by lamellar buckling in the longitudinal orientation followed by shear delamination. Tensile failure in the longitudinal orientation occurred by lamellar delamination combined with tubule pullout and fracture. The structure-property relationships quantified here for bighorn sheep horn keratin can be used to help validate finite element simulations of ram's impacting each other as well as being useful for other analysis regarding horn keratin on other animals. The horn of the bighorn sheep is an anisotropic composite composed of keratin that is highly sensitive to moisture content. Keratin is also found in many other animals in the form of hooves, claws, beaks, and feathers. Only one previous study contains high rate experimental data, which was performed in the dry condition and only in compression. Considering the bighorn sheep horns' protective role in high speed impacts along with the moisture and strain rate sensitivity, more high strain rate data is needed to fully characterize and model the material. This study provides high strain

  8. Self-rating scales assessing subjective well-being and distress correlate with rCBF in PTSD-sensitive regions.

    Science.gov (United States)

    Nardo, D; Högberg, G; Flumeri, F; Jacobsson, H; Larsson, S A; Hällström, T; Pagani, M

    2011-12-01

    The aim of this study was to investigate the distribution of the regional cerebral blood flow (rCBF) in occupational-related post-traumatic stress disorder (PTSD) subjects and to seek possible correlations between brain perfusion and self-rating scales (SRS) in order to cross-check their diagnostic value and to look for their neural correlates. A total of 13 traumatized underground and long-distance train drivers developing (S) and 17 not developing (NS) PTSD who had experienced a 'person under train' accident or who had been assaulted at work underwent clinical assessment and 99mTc-HMPAO SPECT imaging during autobiographical trauma scripts. Statistical parametric mapping was applied to analyse rCBF changes in S as compared with NS and to search for correlations between rCBF and the administered SRS scores, modelling age, months to SPECT and the ratio 'grey matter/intra-cranial volume' as nuisance variables. Significantly higher activity was observed during trauma script in left posterior and anterior insula, posterior cingulate, inferior parietal lobule, precuneus, caudate and putamen in PTSD subjects as compared with the trauma-exposed control group. Impact of Event Scale and World Health Organisation (10) Well-Being Index scores highly correlated with tracer uptake to a great extent in the same regions in which rCBF differences between S and NS were found. These findings support the involvement of insular, cingulate and parietal cortices (as well as the basal ganglia) in the pathogenesis of PTSD and in the processing of related subjective well-being and distress.

  9. 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.

  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. 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.

  12. 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.

  13. Rates of trauma spectrum disorders and risks of posttraumatic stress disorder in a sample of orphaned and widowed genocide survivors.

    Science.gov (United States)

    Schaal, Susanne; Dusingizemungu, Jean-Pierre; Jacob, Nadja; Elbert, Thomas

    2011-01-01

    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 a