Human Correlates of Provocative Questions in Pancreatic Pathology

PubMed Central

McDonald, Oliver G.; Maitra, Anirban; Hruban, Ralph H.

2012-01-01

Studies of cell lines and of animal models of pancreatic cancer have raised a number of provocative questions about the nature and origins of human pancreatic cancer and have provided several leads into exciting new approaches for the treatment of this deadly cancer. In addition, clinicians with little or no contact with human pathology have challenged the way that pancreatic pathology is practiced, suggesting that “genetic signals” may be more accurate than today’s multi-modal approach to diagnoses. In this review we consider eight provocative issues in pancreas pathology, with an emphasis on “the evidence derived from man.” PMID:23060061

Provocation testing to assist craniomandibular pain diagnosis.

PubMed

DuPont, John S; Brown, Christopher E

2010-04-01

Patients with TMD often present with complex pain symptoms, which can make it difficult to reach a diagnosis. Usually palpation of the masticatory muscles and TM joints, range of motion testing and imaging are used in the diagnostic process. Sometimes it is necessary to evaluate the jaw moving muscles from a functional prospective because they cannot be palpated due to inaccessibility or because they have other structures that are more superficial to them. In these instances, provocation testing can be a helpful adjunct in providing some insight into what is occurring in the area being tested and localizing a suspected source of pain. Anesthesia blocking can be used to confirm any positive findings. This article explores several provocation tests that can be used to evaluate conditions of the masticatory musculature, the TM joints and the stylomandibular ligament.

Provocative questions in cancer epidemiology in a time of scientific innovation and budgetary constraints.

PubMed

Lam, Tram Kim; Schully, Sheri D; Rogers, Scott D; Benkeser, Rachel; Reid, Britt; Khoury, Muin J

2013-04-01

In a time of scientific and technological developments and budgetary constraints, the National Cancer Institute's (NCI) Provocative Questions Project offers a novel funding mechanism for cancer epidemiologists. We reviewed the purposes underlying the Provocative Questions Project, present information on the contributions of epidemiologic research to the current Provocative Questions portfolio, and outline opportunities that the cancer epidemiology community might capitalize on to advance a research agenda that spans a translational continuum from scientific discoveries to population health impact.

Painful and provocative events scale and fearlessness about death among Veterans: Exploratory factor analysis.

PubMed

Poindexter, Erin K; Nazem, Sarra; Forster, Jeri E

2017-01-15

The interpersonal theory of suicide suggests three proximal risk factors for suicide: perceived burdensomeness, thwarted belongingness, and acquired capability. Previous literature indicates that repetitive exposure to painful and provocative events is related to increased acquired capability for suicide. Despite this, research related to the assessment of painful and provocative events has been insufficient. Research has inconsistently administered the Painful and Provocative Events Scale (PPES; a painful and provocative events assessment), and no study has examined the factor structure of the English PPES. This study explored the factor structure of the PPES and the relation between factors and fearlessness about death. The sample was a cross-sectional, self-report study comprised of 119 Veterans (Mage = 46.5, SD = 13.5). Findings from an exploratory factor analysis indicated a four-factor solution for the PPES; however, no factor from the PPES significantly related to fearlessness about death (measured by the Acquired Capability for Suicide Scale - Fearlessness About Death Scale; all p >.21). Cross-sectional, small Veteran sample. Findings suggest that the PPES lacks the psychometric properties necessary to reliably investigate painful and provocative factors. Consequently, this measure may not reliably capture and explain how painful and provocative events relate to fearlessness about death, which is a barrier to improving suicide risk assessment and prediction. Recommendations for the construction of a new PPES are offered. Published by Elsevier B.V.

Direct oral provocation tests in non-immediate mild cutaneous reactions related to beta-lactam antibiotics.

PubMed

Vezir, Emine; Dibek Misirlioglu, Emine; Civelek, Ersoy; Capanoglu, Murat; Guvenir, Hakan; Ginis, Tayfur; Toyran, Muge; Kocabas, Can N

2016-02-01

Skin testing has a limited role in the diagnosis of non-immediate beta-lactam hypersensitivity in children. The aim of this study was to report the results of oral provocation tests performed without skin tests in children with non-immediate mild cutaneous reactions without systemic symptoms caused by beta-lactam antibiotics. Oral provocation tests with suspected antibiotics were performed to patients with non-immediate mild cutaneous reactions without systemic symptoms caused by beta-lactam antibiotics. Skin tests were not performed before provocation tests. A total of five doses were administered with half-an-hour intervals in increasing doses. Provocation was continued for 5 days. A total of 119 patients with a median age of 4.3 (IQR: 2-7.5) years, of whom 58% were males, were included in the study. Amoxicillin-clavulanic acid was the most frequently responsible agent in 87 (73.1%) patients, and most common type of rash was maculopapular in 74 (62.2%) patients. Four patients (3.4%) had an urticarial reaction during the provocation test. We did not experience any severe reactions during oral provocation test without previous skin tests performed to children with non-immediate mild cutaneous reactions without systemic symptoms. Omitting skin tests before oral provocation test in this group of children can help decreasing the burden of allergy clinics and alleviating the discomfort of children. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Exogenous Testosterone Enhances the Reactivity to Social Provocation in Males

PubMed Central

Wagels, Lisa; Votinov, Mikhail; Kellermann, Thilo; Eisert, Albrecht; Beyer, Cordian; Habel, Ute

2018-01-01

Testosterone affects human social behavior in various ways. While testosterone effects are generally associated with muscular strength and aggressiveness, human studies also point towards enhanced status–seeking motives after testosterone administration. The current study tested the causal influence of exogenous testosterone on male behavior during a competitive provocation paradigm. In this double blind, randomized, placebo (PL)-controlled study, 103 males were assigned to a PL or testosterone group receiving a colorless PL or testosterone gel. To induce provocation, males played a rigged reaction time game against an ostensible opponent. When participants lost, the opponent subtracted money from the participant who in return could subtract money from the ostensible opponent. Participants subjectively indicated anger and self-estimated treatment affiliation (testosterone or PL administration). A trial-by-trial analysis demonstrated that provocation and success during the repeated games had a stronger influence on participants’ choice to reduce money from the opponent if they had received testosterone. Participants who believed to be in the testosterone group were angrier after the experiment and increased monetary reductions during the task course. In line with theories about mechanisms of testosterone in humans, provocation is shown to be necessary for the agency of exogenous testosterone. Thus, testosterone reinforces the conditional adjustment of aggressive behavior but not aggressive behavior per se. In contrast undirected frustration is not increased by testosterone but probably interferes with cognitive appraisals about biological mechanisms of testosterone. PMID:29551966

Exogenous Testosterone Enhances the Reactivity to Social Provocation in Males.

PubMed

Wagels, Lisa; Votinov, Mikhail; Kellermann, Thilo; Eisert, Albrecht; Beyer, Cordian; Habel, Ute

2018-01-01

Testosterone affects human social behavior in various ways. While testosterone effects are generally associated with muscular strength and aggressiveness, human studies also point towards enhanced status-seeking motives after testosterone administration. The current study tested the causal influence of exogenous testosterone on male behavior during a competitive provocation paradigm. In this double blind, randomized, placebo (PL)-controlled study, 103 males were assigned to a PL or testosterone group receiving a colorless PL or testosterone gel. To induce provocation, males played a rigged reaction time game against an ostensible opponent. When participants lost, the opponent subtracted money from the participant who in return could subtract money from the ostensible opponent. Participants subjectively indicated anger and self-estimated treatment affiliation (testosterone or PL administration). A trial-by-trial analysis demonstrated that provocation and success during the repeated games had a stronger influence on participants' choice to reduce money from the opponent if they had received testosterone. Participants who believed to be in the testosterone group were angrier after the experiment and increased monetary reductions during the task course. In line with theories about mechanisms of testosterone in humans, provocation is shown to be necessary for the agency of exogenous testosterone. Thus, testosterone reinforces the conditional adjustment of aggressive behavior but not aggressive behavior per se . In contrast undirected frustration is not increased by testosterone but probably interferes with cognitive appraisals about biological mechanisms of testosterone.

Brain responses to symptom provocation and trauma-related short-term memory recall in coal mining accident survivors with acute severe PTSD.

PubMed

Hou, Cailan; Liu, Jun; Wang, Kun; Li, Lingjiang; Liang, Meng; He, Zhong; Liu, Yong; Zhang, Yan; Li, Weihui; Jiang, Tianzi

2007-05-04

Functional neuroimaging studies have largely been performed in patients with longstanding chronic posttraumatic stress disorder (PTSD). Additionally, memory function of PTSD patients has been proved to be impaired. We sought to characterize the brain responses of patients with acute PTSD and implemented a trauma-related short-term memory recall paradigm. Individuals with acute severe PTSD (n=10) resulting from a mining accident and 7 men exposed to the mining accident without PTSD underwent functional magnetic resonance imaging (fMRI) while performing the symptom provocation and trauma-related short-term memory recall paradigms. During symptom provocation paradigm, PTSD subjects showed diminished responses in right anterior cingulate gyrus, left inferior frontal gyrus and bilateral middle frontal gyrus and enhanced left parahippocampal gyrus response compared with controls. During the short-term memory recall paradigm, PTSD group showed diminished responses in right inferior frontal gyrus, right middle frontal and left middle occipital gyrus in comparison with controls. PTSD group exhibited diminished right parahippocampal gyrus response during the memory recall task as compared to the symptom provocation task. Our findings suggest that neurophysiological alterations and memory performance deficit have developed in acute severe PTSD.

Clinical tube weaning supported by hunger provocation in fully-tube-fed children.

PubMed

Hartdorff, Caroline M; Kneepkens, C M Frank; Stok-Akerboom, Anita M; van Dijk-Lokkart, Elisabeth M; Engels, Michelle A H; Kindermann, Angelika

2015-04-01

Children with congenital malformations, mental retardation, and complex early medical history frequently have feeding problems. Although tube feeding is effective in providing the necessary energy and nutrients, it decreases the child's motivation to eat and may lead to oral aversion. In this study, we sought to confirm our previous results, showing that a multidisciplinary clinical hunger provocation program may lead to quick resumption of oral feeding. In a crossover study, 22 children of 9 to 24 months of age who were fully dependent on tube feeding were randomly assigned to one of two groups: group A, intervention group (2-week multidisciplinary clinical hunger provocation program); and group B, control group (4-week outpatient treatment by the same multidisciplinary team). Patients failing one treatment were reassigned to the other treatment group. Primary outcome measures were at least 75% orally fed at the conclusion of the intervention and fully orally fed and gaining weight 6 months after the intervention. In group A, 9/11 patients were successfully weaned from tube feeding (2 failures: 1 developed ulcerative colitis, 1 drop-out). In group B, only 1 patient was weaned successfully; 10/11 were reassigned to the clinical hunger provocation program, all being weaned successfully. Six months after the intervention, 1 patient had to resume tube feeding. In total, in the control group, 1/11 (9%) was weaned successfully as compared with 18/21 (86%) in the hunger provocation group (P < 0.001). Multidisciplinary clinical hunger provocation is an effective short-term intervention for weaning young children from tube feeding.

Perpetrators and targets of bullying at work: role stress and individual differences.

PubMed

Matthiesen, Stig Berge; Einarsen, Ståle

2007-01-01

A workplace survey study (N = 2215, response rate 47%) revealed that about 16% of the sample may be categorized as either perpetrators (5.4%), provocative victims (2.1%), or as targets of bullying (8.3%). Targets of bullying, provocative victims, and bullies were compared with those 84% who do not report any involvement with respect to bullying at work, self-esteem, aggressive tendencies, prior experiences of bullying, or experiences of role stress. Perpetrators were found to have a higher level of aggression than did the comparison group and the targets. Provocative victims manifested a low level of self-esteem and social competency combined with a high level of aggressiveness. Targets of bullying revealed low levels of self-esteem and social competency. Targets, provocative victims, and perpetrators reported elevated levels of role stress in the form of unclear or conflicting demands and expectations around work tasks and daily work.

North Korea’s Choice of the Types of Provocation Against South Korea

DTIC Science & Technology

2013-12-01

DISTRIBUTION CODE A 13. ABSTRACT (maximum 200 words) This research starts from the question of how North Korea decides upon the types of its provocations...INTENTIONALLY LEFT BLANK iv ABSTRACT This research starts from the question of how North Korea decides upon the types of its provocations...1 A. MAJOR RESEARCH QUESTION................................................................1 B

Cardiovascular and cortisol reactivity and habituation to a virtual reality version of the Trier Social Stress Test: a pilot study.

PubMed

Jönsson, Peter; Wallergård, Mattias; Osterberg, Kai; Hansen, Ase Marie; Johansson, Gerd; Karlson, Björn

2010-10-01

The Trier Social Stress Test (TSST) is a widely used protocol to induce stress in laboratory settings. Briefly, in the TSST, the test participant is asked to hold a speech and to do an arithmetic task in front of an audience. In the present pilot study, we examined endocrine and autonomic reactivity and habituation to repeated stress provocations using a virtual reality (VR) version of TSST. The VR system was a CAVE™ system with three rear projected walls (4 m×3 m), and one floor projection. The system also included a head tracking system and passive stereoscopy. The virtual audience consisted of one woman, and two men. Ten healthy men, mean age 28.3 years (24-38 years), were confronted with the test twice (1 week between sessions), during which salivary cortisol, heart rate (HR), high frequency heart rate variability (HF-HRV, parasympathetic activity), and T-wave amplitude (TWA, suggested to be related to sympathetic influence on myocardial performance) were assessed. Cortisol secretion showed a marked increase (88% vs. baseline) during the first stress provocation, but habituated in the second session. The magnitude of HR and TWA reactivity during stress provocation was approximately the same at both sessions, implying a stable increase in sympathetic activity. Heart rate showed a maximum increase of 40% at the first session, and 32% at the second. TWA showed a maximum decrease of 42% at the first session, and 39% at the second. The results resemble those obtained in prior studies using the real-life TSST. If these results can be replicated with larger samples, VR technology may be used as a simple and standardized tool for social stress induction in experimental settings. Copyright © 2010 Elsevier Ltd. All rights reserved.

Oxytocin strengthens the link between provocation and aggression among low anxiety people.

PubMed

Pfundmair, Michaela; Reinelt, Annika; DeWall, C Nathan; Feldmann, Lisa

2018-07-01

Oxytocin (OT) not only modulates positive social interactions but also affects negative ones. Several studies have established a link between OT and aggression. However, they also resulted in an inconsistent picture and showed methodological issues. The current studies aimed to address these lacks and test the hypothesis that OT increases provocation-induced aggression in people low in anxiety. Therefore, two studies with 56 males (Study 1) as well as 40 females and 24 males (Study 2) were conducted. After responding to a trait anxiety questionnaire, participants self-administered OT or a placebo. Thereafter, provocation was manipulated by rejecting vs. accepting (Study 1) or insulting vs. accepting (Study 2) the participants by real human counterparts. Aggressive behavior was quantified by measuring how much hot sauce (Study 1) or unpleasant blasts of white noise (Study 2) participants delivered to their opponents, using two classic aggression paradigms. Both studies provided evidence that OT promotes aggression in response to provocation in low anxiety people which was not the case with no provocation or in high anxiety people. These findings confirm the idea that OT can be involved in the creation of aggressive behavior when accounting for situational and dispositional features. Copyright © 2018 Elsevier Ltd. All rights reserved.

Cortisol responses to naturalistic and laboratory stress in student teachers: comparison with a non-stress control day.

PubMed

Wolfram, Maren; Bellingrath, Silja; Feuerhahn, Nicolas; Kudielka, Brigitte M

2013-04-01

Ambulatory assessments of hypothalamus-pituitary-adrenal axis responses to acute natural stressors yield evidence on stress regulation with high ecological validity. Sampling of salivary cortisol is a standard technique in this field. In 21 healthy student teachers, we assessed cortisol responses to a demonstration lesson. On a control day, sampling was repeated at analogous times. Additionally, the cortisol awakening response (CAR) was assessed on both days. Participants were also exposed to a laboratory stressor, the Trier Social Stress Test, and rated their individual levels of chronic work stress. In pre-to-post-stress assessment, cortisol levels declined after the lesson. However, post-stress cortisol levels were significantly higher compared with those on the control day. Also, the Trier Social Stress Test yielded higher cortisol responses when using the control day as reference baseline. Associations between the CAR and chronic stress measures were observed solely on the control day. There were no significant associations between cortisol responses to the natural and laboratory stressors. Our results indicate that a control day might be an important complement in laboratory but especially in ambulatory stress research. Furthermore, associations between chronic stress measures and the CAR might be obscured by acute stress exposure. Finally, responses to the laboratory stressor do not seem to mirror natural stress responses. Copyright © 2012 John Wiley & Sons, Ltd.

Philosophical Provocation: The Lifeblood of Clinical Ethics.

PubMed

McCullough, Laurence B

2017-02-01

The daily work of the clinical ethics teacher and clinical ethics consultant falls into the routine of classifying clinical cases by ethical type and proposing ethically justified alternatives for the professionally responsible management of a specific type of case. Settling too far into this routine creates the risk of philosophical inertia, which is not good either for the clinical ethicist or for the field of clinical ethics. The antidote to this philosophical inertia and resultant blinkered vision of clinical ethics is sustained, willing exposure to philosophical provocation. The papers in this clinical ethics issue of the Journal of Medicine and Philosophy provide just such philosophical provocation related to core topics in clinical ethics: the distinction between clinical practice and clinical research; telemedicine, or medicine at a distance; illness narratives; the concept of the placebo effect; and sex reassignment. © The Author 2017. Published by Oxford University Press, on behalf of the Journal of Medicine and Philosophy Inc. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Ultra-long acting calcium channel blockers may decrease accuracy of the acetylcholine provocation test.

PubMed

Kurabayashi, Manabu; Asano, Mitsutoshi; Shimura, Tsukasa; Suzuki, Hidetoshi; Aoyagi, Hideshi; Yamauchi, Yasuteru; Okishige, Kaoru; Ashikaga, Takashi; Isobe, Mitsuaki

2017-06-01

When drug-induced coronary spasm provocation tests are performed, a washout period of >48h for calcium channel blockers (CCBs) is uniformly recommended. However, each CCB has a distinct half-life, and little is known about the influence of prior oral administration of CCBs on acetylcholine provocation test to evaluate coronary vasomotor reaction. We examined 245 consecutive patients with suspected vasospastic angina who had undergone acetylcholine provocation test. Of those patients, 29 patients had been on amlodipine, an ultra-long term acting CCB (group A), 34 on other CCBs (group O), and 182 patients on no CCB (group N). After CCBs had been withheld > 48h, we performed acetylcholine provocation, which resulted in 152 positive, 36 intermediate, and 57 negative reactions. We evaluated coronary artery tone calculated as follows: (luminal diameter after nitrate-baseline luminal diameter)÷(luminal diameter after nitrate)×100 (%). In group A patients, coronary artery tone was lower (A:9.1±6.9% vs. O:11.7±8.3% vs. N:12.1±8.5%, p=0.0011) and the positive rate of acetylcholine provocation test was lower than group O and group N (A:41% vs. O:68% vs. N:64%, p=0.047). Multivariate logistic analysis showed that taking amlodipine until 2days before acetylcholine provocation test was a significant inverse predictor for acetylcholine-provoked coronary spasm (odds ratio 0.327; 95% confidence interval 0.125-0.858, p=0.023). Residual vasodilatory effects of ultra-long acting CCB may decrease coronary artery tone and the vasoconstrictive reaction to acetylcholine suggesting that a 2-day pre-test drug holiday may not be long enough. Copyright © 2017 Elsevier B.V. All rights reserved.

Assaultive behavior. Does provocation begin in the front office?

PubMed

Blair, D T

1991-05-01

1. Provocation is an important risk predictor because these issues can be recognized, assessed, and appropriate interventions can be implemented to reduce the associated risks. It is only by the reduction of such "non-fixed" risk factors that any reduction of assaults can be accomplished. 2. Involuntary admission, patients with dementia or organic brain disorder, physical or verbal limits, staff attitude, denial of the possibility of assaults, and the educational level and clinical experience of the staff may help provoke an assaultive episode. 3. An important step is assessing the assault to identify provocation due to certain medical causes, and to document the extent of degeneration in patients with dementia or organic brain disorder. Medical intervention would be indicated and would appropriately address the causes of some violent episodes.

Impulsivity and suicidality: the mediating role of painful and provocative experiences.

PubMed

Bender, Theodore W; Gordon, Kathryn H; Bresin, Konrad; Joiner, Thomas E

2011-03-01

Multiple studies have reported a link between high levels of impulsivity and suicidal behavior. Joiner's (2005) explanation for this link is that impulsive individuals have a greater tendency to experience painful and provocative events that habituate them to fear and pain, which leads to an acquired capability for engaging in suicidal behavior. Study 1 tested Joiner's (2005) hypothesis in a sample of 182 undergraduate students who completed self-report questionnaires on impulsivity, frequency of painful and provocative events, and acquired capability for suicide. In addition to self-report, pain tolerance (an aspect of acquired capability for suicide) was measured with a pressure algometer. Study 2 sought to replicate our findings from Study 1 in a sample of 516 clinical outpatients using a multi-faceted measure of impulsivity. Consistent with prediction, product of coefficients tests for mediation (MacKinnon et al., 2002) revealed that impulsivity has an indirect relationship with acquired capability for suicidal behavior, and that this relationship is mediated by painful and provocative events. Data from our studies are cross-sectional in nature, which does not allow for conclusions about the temporal ordering of our variables. In addition, self-report was used to measure most variables. Future research may benefit from a longitudinal design and the inclusion of other modes of assessment (e.g., behavioral measures of impulsivity). Our findings suggest that the link between impulsivity and suicidal behavior occurs because impulsive people tend to have a greater capability for suicidal behavior, which they have acquired through experiencing painful and provocative events. Copyright © 2010 Elsevier B.V. All rights reserved.

Association between composites of selected motion palpation and pain provocation tests for sacroiliac joint disorders.

PubMed

Soleimanifar, Manijeh; Karimi, Noureddin; Arab, Amir Massoud

2017-04-01

The sacroiliac joint (SIJ) has been implicated as a potential source of low back and buttock pain. Several types of motion palpation and pain provocation tests are used to evaluate SIJ dysfunction. The purpose of this study was to investigate the relationship between motion palpation and pain provocation tests in assessment of SIJ problems. This study is Descriptive Correlation. 50 patients between the ages of 20 and 65 participated. Four motion palpation tests (Sitting flexion, Standing flexion, Prone knee flexion, Gillet test) and three pain provocation tests (FABER, Posterior shear, Resisted abduction test) were examined. Chi-square analysis was used to assess the relationship between results of the individuals and composites of these two groups of tests. No significant relationship was found between these two groups of tests. It seems that motion palpation tests assess SIJ dysfunction and provocative tests assessed SIJ pain which do not appear to be related. Copyright © 2016 Elsevier Ltd. All rights reserved.

Physical aggression as a function of perceived fighting ability and provocation: an experimental investigation.

PubMed

Archer, John; Benson, David

2008-01-01

In three studies, Resource Holding Power (RHP) and provocation were manipulated in scenarios involving a young person in a bar with friends. In Study 1, teenage men reported lower likelihood of responding with physical aggression when insulted as levels of three RHP cues (size, allies and reputation) increased, effects that were accentuated by combinations of high-RHP cues; in the second part of this study, they consistently rated an insult to their girlfriend as the most provoking from a range of possible provocations, chosen on theoretical and empirical grounds. Study 2 replicated the results of the first part of Study 1 in samples of men and women in their twenties, although the effects were weaker at low levels of RHP. Study 3 combined a high- or low-provoking event, with low, medium or high RHP, and a wider range of response choices. As expected, direct aggression increased as provocation increased and RHP decreased. Delayed aggressive responses, including revenge fantasies, were highest in response to high provocation and high RHP. Findings are discussed in relation to theoretical models of aggressive motivation. (c) 2007 Wiley-Liss, Inc.

Inhaled Mannitol as a Laryngeal and Bronchial Provocation Test.

PubMed

Tay, Tunn Ren; Hoy, Ryan; Richards, Amanda L; Paddle, Paul; Hew, Mark

2017-03-01

Timely diagnosis of vocal cord dysfunction (VCD), more recently termed "inducible laryngeal obstruction," is important because VCD is often misdiagnosed as asthma, resulting in delayed diagnosis and inappropriate treatment. Visualization of paradoxical vocal cord movement on laryngoscopy is the gold standard for diagnosis, but is limited by poor test sensitivity. Provocation tests may improve the diagnosis of VCD, but the diagnostic performance of current tests is less than ideal. Alternative provocation tests are required. This pilot study demonstrates the feasibility of using inhaled mannitol for concurrent investigation of laryngeal and bronchial hyperresponsiveness. Consecutive patients with suspected VCD seen at our institution's asthma clinic underwent flexible laryngoscopy at baseline and following mannitol challenge. VCD was diagnosed on laryngoscopy based on inspiratory adduction, or >50% expiratory adduction of the vocal cords. Bronchial hyperresponsiveness after mannitol challenge was also assessed. We evaluated the interrater agreement of postmannitol laryngoscopy between respiratory specialists and laryngologists. Fourteen patients with suspected VCD in the context of asthma evaluation were included in the study. Mannitol provocation demonstrated VCD in three of the seven patients with normal baseline laryngoscopy (42.9%). Only two patients had bronchial hyperresponsiveness. There was substantial interrater agreement between respiratory specialists and laryngologists, kappa = 0.696 (95% confidence interval: 0.324-1) (P = 0.006). Inhaled mannitol can be used to induce VCD. It is well tolerated and can evaluate laryngeal and bronchial hyperresponsiveness at the same setting. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Peer Provocation in Physical Education: Experiences of Botswana Adolescents

ERIC Educational Resources Information Center

Shehu, Jimoh

2009-01-01

Critical incidents of peer provocation in physical education were investigated among 675 junior secondary school students in Botswana. Data were generated through a brief, open-ended questionnaire requesting the students to narrate their experiences of bad, hurtful and offensive peer behaviours during physical education classes. Six overlapping…

Intracoronary Acetylcholine Provocation Testing for Assessment of Coronary Vasomotor Disorders.

PubMed

Ong, Peter; Athanasiadis, Anastasios; Sechtem, Udo

2016-08-18

Intracoronary acetylcholine provocation testing (ACH-test) is an established method for assessment of epicardial coronary artery spasm in the catheterization laboratory which was introduced more than 30 years ago. Due to the short half-life of acetylcholine it can only be applied directly into the coronary arteries. Several studies have demonstrated the safety and clinical usefulness of this test. However, acetylcholine testing is only rarely applied in the U.S. or Europe. Nevertheless, it has been shown that 62% of Caucasian patients with stable angina and unobstructed coronary arteries on coronary angiography suffer from coronary vasomotor disorders that can be diagnosed with acetylcholine testing. In recent years it has been appreciated that the ACH-test not only assesses the presence of epicardial spasm but that it can also be useful for the detection of coronary microvascular spam. In such cases no epicardial spasm is seen after injection of acetylcholine but ischemic ECG shifts are present together with a reproduction of the patient's symptoms during the test. This article describes the experience with the ACH-test and its implementation in daily clinical routine.

ALLERGEN PROVOCATION AUGMENTS ENDOTOXIN-INDUCED NASAL INFLAMMATION IN ATOPIC ASTHMATICS

EPA Science Inventory

Background: Recent epidemiologic and in vivo studies have suggested that inhaled endotoxin plays an important role in asthma pathogenesis.
Objective: The present study examines the effect of nasal allergen provocation on subsequent endotoxin challenges in subjects with atopi...

Provocative Pedagogies in e-Learning: Making the Invisible Visible

ERIC Educational Resources Information Center

Sinclair, Anne

2009-01-01

The purpose of this case study was to explore the experiences of participants (practicing teachers) involved in an online course entitled: "Reflective Practice for Teachers." Using a provocative pedagogy in the course, the teachers were challenged to confront beliefs and assumptions about teaching and learning and become active participants in the…

Creating Crossroads for Self-Authorship: Investigating the Provocative Moment

ERIC Educational Resources Information Center

Pizzolato, Jane Elizabeth

2005-01-01

Through examination of 613 students' narratives about self-selected important decisions, I investigated the student and situation characteristics related to provocation and use of self authored ways of knowing. The findings gesture toward both particular skills students may need to develop in order to self-author, as well as suggest that movement…

Stress-induced laboratory eating behavior in obese women with binge eating disorder.

PubMed

Schulz, S; Laessle, R G

2012-04-01

Aim of the study was to compare the microstructural eating behavior of obese patients with and without binge eating disorder (BED) after stress induction in laboratory. Seventy-one female subjects were investigated (mean BMI 36.9). Thirty-five fulfilled criteria for BED. A 2×2 factorial design with repeated measurement (stress vs. no stress) on the second factor was applied. Stress was induced by the Trier Social Stress Test (TSST) and chocolate pudding served as laboratory food. Variables of eating behavior were measured by a universal eating monitor (UEM). Only in participants with BED stress was associated with an increase in the initial eating rate and a diminished deceleration of eating at the end of the meal. Generally, BED subjects ate with larger size of spoonfuls during the laboratory meal than non BED controls. The eating behavior of obese patients with binge eating disorder seems to be significantly affected by stress. The stress-induced eating behavior of BED patients is characterized by a stronger motivation to eat (indicated by a fast initial eating rate) as well as by a lack of satiety perception (indicated by less deceleration of eating rate). Copyright © 2011 Elsevier Ltd. All rights reserved.

Correcting for possible tissue distortion between provocation and assessment in skin testing: the divergent beam UVB photo-test.

PubMed

O'Doherty, Jim; Henricson, Joakim; Falk, Magnus; Anderson, Chris D

2013-11-01

In tissue viability imaging (TiVi), an assessment method for skin erythema, correct orientation of skin position from provocation to assessment optimizes data interpretation. Image processing algorithms could compensate for the effects of skin translation, torsion and rotation realigning assessment images to the position of the skin at provocation. A reference image of a divergent, UVB phototest was acquired, as well as test images at varying levels of translation, rotation and torsion. Using 12 skin markers, an algorithm was applied to restore the distorted test images to the reference image. The algorithm corrected torsion and rotation up to approximately 35 degrees. The radius of the erythemal reaction and average value of the input image closely matched that of the reference image's 'true value'. The image 'de-warping' procedure improves the robustness of the response image evaluation in a clinical research setting and opens the possibility of the correction of possibly flawed images performed away from the laboratory setting by the subject/patient themselves. This opportunity may increase the use of photo-testing and, by extension, other late response skin testing where the necessity of a return assessment visit is a disincentive to performance of the test. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Laboratory-Induced Stress and Craving among Individuals with Prescription Opioid Dependence

PubMed Central

Back, Sudie E.; Gros, Daniel F.; Price, Matthew; LaRowe, Steve; Flanagan, Julianne; Brady, Kathleen T.; Davis, Charles; Jaconis, Maryanne; McCauley, Jenna L.

2015-01-01

Background Stress and conditioned drug cues have been implicated in the initiation, maintenance and relapse to substances of abuse. Although stress and drug cues are often encountered together, little research exists on whether stress potentiates the response to drug cues. Method Participants (N = 75) were 39 community recruited individuals with current prescription opioid (PO) dependence and 36 healthy controls. Participants stayed overnight in the hospital for one night and then completed laboratory testing the following morning. During laboratory testing, participants were randomly assigned to a stress task (Trier Social Stress Task; TSST) or a no-stress condition. Following the stress manipulation, all participants completed a PO cue paradigm. Immediately before and after the stress and cue tasks, the following were assessed: subjective (stress, craving, anger, sadness, happiness), physiological (heart rate, blood pressure, galvanic skin response), and neuroendocrine responses (cortisol and dehydroepiandrosterone). Results Internal validity of the stress task was demonstrated, as evidenced by significantly higher subjective stress, as well as cortisol, heart rate and blood pressure in the TSST compared to the no-stress group. Individuals with PO dependence evidenced significantly greater reactivity to the stress task than controls. Craving increased significantly in response to the drug cue task among PO participants. No stress × cue interaction was observed. Conclusions In this study, heightened stress reactivity was observed among individuals with PO dependence. Exposure to acute stress, however, did not potentiate craving in response to conditioned drug cues. PMID:26342626

Stress-induced laboratory eating behavior in obese women with binge eating disorder.

PubMed

Laessle, Reinhold G; Schulz, Simone

2009-09-01

To compare the microstructural eating behavior of obese patients with and without binge eating disorder (BED) after stress induction in laboratory. Forty-eight obese women were investigated. Seventeen were assigned to the group of BED. Group (BED vs. non-BED) by condition (stress vs. no stress) interaction effect on feeding variables, measured by a universal eating monitor, was tested. Stress was induced by the trier social stress test (TSST) and chocolate pudding served as laboratory food. From the nonstress to the stress condition, patients with BED, when compared with non-BED had a greater increase in average eating rate (p < .01) and a corresponding greater increase in the frequency of spoonfuls (p < .02). The BED group also showed a different change in acceleration/deceleration from the nonstress to the stress condition compared to the non-BED group (p < .04). Obese individuals with BED appear to exhibit a different response to stress than obese non-BED individuals and individuals with bulimia nervosa.

Individual differences in responses to provocation and frequent victimization by peers.

PubMed

Champion, Kelly M; Clay, Daniel L

2007-02-01

This study examined associations between victimization by peers and intention to respond to provocative events as a function of anger arousal and motivation to improve the situation in a cross-sectional sample of school-age children (N = 506, 260 males, 246 females). Results demonstrated that more intense anger and more retaliatory motivation were positively associated with intentions to aggress and with frequency of victimization. The association between aggressive intentions to respond to anger provocation and victimization could be accounted for by subjective feelings of anger and motivation to retaliate. The contribution of emotion processes was stronger for boys than for girls. A post hoc examination of non-bullying participants revealed that motivation accounted for aggressive intentions among the non-bullies. Results support including anger management programs in prevention efforts that target the school climate and victims' risk for psychopathology.

Aggression in Children with Conduct Problems and Callous-Unemotional Traits: Social Information Processing and Response to Peer Provocation.

PubMed

Helseth, Sarah A; Waschbusch, Daniel A; King, Sara; Willoughby, Michael T

2015-11-01

Callous/unemotional traits (CU) moderate children's conduct problems (CP) in numerous domains, including social functioning. The present study examined whether CU traits also moderate the aggressiveness of children's social information processing (SIP) and responses to varying intensities of peer provocation. Sixty elementary school-age children (46 males) were grouped into those without CP or CU (controls, n = 32), those with CP but not CU (CP-only; n = 14), and those with both CP and CU (CPCU, n = 14). Participants completed a task that measured two aspects of SIP (response generation and hostile attribution bias) and a computerized reaction time task (CRTT) that measured behavior, affect, and communication before and after provocation under instrumental and hostile aggressive conditions. Children with CPCU generated more aggressive responses than controls on measures of SIP. On the CRTT, all children exhibited reactive aggression following high provocation, but only children with CPCU exhibited proactive aggression, and reactive aggression following low provocation; no differences in affect were found. In a series of exploratory analyses, CPCU children communicated antisocially, while CP-only communicated prosocially. Finally, children with CPCU did not seem to hold a grudge following the final instance of provocation, instead gradually returning to baseline like their non-CU peers. These distinct social cognitive and behavioral profiles hint at different etiologies of CP and CPCU, underscoring the variability of aggression in these populations.

Social provocation modulates decision making and feedback processing: Examining the trajectory of development in adolescent participants.

PubMed

Pincham, Hannah L; Wu, Claire; Killikelly, Clare; Vuillier, Laura; Fearon, R M Pasco

2015-10-01

Increasingly, research is turning to the ways in which social context impacts decision making and feedback processing in adolescents. The current study recorded electroencephalography to examine the trajectory of development across adolescence, with a focus on how social context impacts cognition and behaviour. To that end, younger (10-12 years) and older (14-16 years) adolescents played a modified Taylor Aggression Paradigm against two virtual opponents: a low-provoker and a high-provoker. During the task's decision phase (where participants select punishment for their opponent), we examined two event-related potentials: the N2 and the late positive potential (LPP). During the outcome phase (where participants experience win or loss feedback), we measured the feedback related negativity (FRN). Although N2 amplitudes did not vary with provocation, LPP amplitudes were enhanced under high provocation for the younger group, suggesting that emotional reactivity during the decision phase was heightened for early adolescents. During the outcome phase, the FRN was reduced following win outcomes under high provocation for both groups, suggesting that a highly provocative social opponent may influence the reward response. Collectively, the data argue that social context is an important factor modulating neural responses in adolescent behavioural and brain development. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Can conjunctival provocation test facilitate the diagnosis of food allergy in children?

PubMed

Krane Kvenshagen, B; Jacobsen, M; Halvorsen, R

2010-01-01

Food allergy is common in children, occurring in 5-7.5%. The diagnosis may, however, be difficult. Elevated IgE or positive skin prick test to a food allergen is often considered proof of allergy, but may represent sensitisation without clinical manifestations. For a precise diagnosis oral challenge is necessary, but this is often not performed because of risk of serious allergic reactions. The aim of this study was to evaluate whether conjunctival provocation test would facilitate the diagnosis of IgE-mediated food allergy. One hundred and forty-nine children with 174 possible diagnoses of food allergy were included. General examination, skin prick test and specific IgE were performed, as well as conjunctival provocation test of the suspected food allergen. Open food challenges and double-blind placebo controlled tests were performed in order to diagnose possible food allergy. Forty-six children with strongly positive conjunctival reactions (rubor, itching, oedema) to fifty food allergens were all proven to have allergy to the food in question. The children with negative conjunctival provocation tests showed no allergic reactions when challenged. We find that a strongly positive conjunctival reaction to a food allergen correlates well with true allergy. An oral challenge should be carefully performed. With a negative conjunctival test an oral challenge may safely be performed. Copyright © 2009 SEICAP. Published by Elsevier Espana. All rights reserved.

Pacifists and Revenge-Seekers in Response to Unambiguous Peer Provocation.

PubMed

McDonald, Kristina L; Asher, Steven R

2018-01-19

In order to better understand why some children retaliate when they feel provoked and others do not, the present study identified "pacifistically-oriented" children who made negative interpretations in response to unambiguous provocations, yet did not endorse revenge goals, and compared them to "revenge-seeking" children who also made negative interpretations but did endorse revenge goals. Groups were identified based on seventh graders' (N = 367; 54.77% male; 22.89% racial/ethnic minority) responses to hypothetical situations in which a peer excluded and insulted them. Comparing these groups revealed that Pacifists endorsed relationship-maintaining goals and emotion regulation goals more highly than Revenge-Seekers. Revenge-Seekers reported more anger and endorsed beliefs about negative reciprocity and aggression being legitimate more highly than Pacifists. Additionally, Revenge-Seekers were more disrespect sensitive than were Pacifists, based on a measure of vigilance for signs of disrespect and expectations that others would disrespect them. Together these findings point to social-cognitive and emotion-related processes that may inhibit revenge-seeking in unambiguous provocation situations, even when children interpret the peer's behavior quite negatively.

Earthquake stress drop and laboratory-inferred interseismic strength recovery

USGS Publications Warehouse

Beeler, N.M.; Hickman, S.H.; Wong, T.-F.

2001-01-01

We determine the scaling relationships between earthquake stress drop and recurrence interval tr that are implied by laboratory-measured fault strength. We assume that repeating earthquakes can be simulated by stick-slip sliding using a spring and slider block model. Simulations with static/kinetic strength, time-dependent strength, and rate- and state-variable-dependent strength indicate that the relationship between loading velocity and recurrence interval can be adequately described by the power law VL ??? trn, where n=-1. Deviations from n=-1 arise from second order effects on strength, with n>-1 corresponding to apparent time-dependent strengthening and n<-1 corresponding to weakening. Simulations with rate and state-variable equations show that dynamic shear stress drop ????d scales with recurrence as d????d/dlntr ??? ??e(b-a), where ??e is the effective normal stress, ??=??/??e, and (a-b)=d??ss/dlnV is the steady-state slip rate dependence of strength. In addition, accounting for seismic energy radiation, we suggest that the static shear stress drop ????s scales as d????s/dlntr ??? ??e(1+??)(b-a), where ?? is the fractional overshoot. The variation of ????s with lntr for earthquake stress drops is somewhat larger than implied by room temperature laboratory values of ?? and b-a. However, the uncertainty associated with the seismic data is large and the discrepancy between the seismic observations and the rate of strengthening predicted by room temperature experiments is less than an order of magnitude. Copyright 2001 by the American Geophysical Union.

Hostile attribution biases for relationally provocative situations and event-related potentials.

PubMed

Godleski, Stephanie A; Ostrov, Jamie M; Houston, Rebecca J; Schlienz, Nicolas J

2010-04-01

This exploratory study investigates how hostile attribution biases for relationally provocative situations may be related to neurocognitive processing using the P300 event-related potential. Participants were 112 (45 women) emerging adults enrolled in a large, public university in upstate New York. Participants completed self-report measures on relational aggression and hostile attribution biases and performed an auditory perseveration task to elicit the P300. It was found that hostile attribution biases for relational provocation situations was associated with a larger P300 amplitude above and beyond the role of hostile attribution biases for instrumental situations, relational aggression, and gender. Larger P300 amplitude is interpreted to reflect greater allocation of cognitive resources or enhanced "attending" to salient stimuli. Implications for methodological approaches to studying aggression and hostile attribution biases and for theory are discussed, as well as implications for the fields of developmental psychology and psychopathology. Copyright 2010 Elsevier B.V. All rights reserved.

Cognitive reactivity to sad mood provocation and the prediction of depressive relapse.

PubMed

Segal, Zindel V; Kennedy, Sidney; Gemar, Michael; Hood, Karyn; Pedersen, Rebecca; Buis, Tom

2006-07-01

Episode remission in unipolar major depression, while distinguished by minimal symptom burden, can also be a period of marked sensitivity to emotional stress as well as an increased risk of relapse. To examine whether mood-linked changes in dysfunctional thinking predict relapse in recovered patients who were depressed. In phase 1 of this study, patients with major depressive disorder were randomly assigned to receive either antidepressant medication or cognitive behavior therapy. In phase 2, patients who achieved clinical remission underwent sad mood provocation and were then observed with regular clinical assessments for 18 months. Outpatient psychiatric clinics at the Centre for Addiction and Mental Health, Toronto, Ontario. A total of 301 outpatients with major depressive disorder, aged 18 to 65 years, participated in phase 1 of this study and 99 outpatients with major depressive disorder in remission, aged 18 to 65 years, participated in phase 2. Occurrence of a relapse meeting DSM-IV criteria for a major depressive episode as assessed by the longitudinal interval follow-up evaluation and a Hamilton Depression Rating Scale score of 16 or greater. Patients who recovered through antidepressant medication showed greater cognitive reactivity following the mood provocation than those who received cognitive behavior therapy. Regardless of type of prior treatment, the magnitude of mood-linked cognitive reactivity was a significant predictor of relapse over the subsequent 18 months. Patients whose mood-linked endorsement of dysfunctional attitudes increased by a minimum of 8 points had a significantly shorter time to relapse than those whose scores were not as elevated. The vulnerability of remitted depressed patients for illness relapse may be related to the (re)activation of depressive thinking styles triggered by temporary dysphoric states. This is the first study to link such differences to prognosis following successful treatment for depression. Further

Teens With Heavy Prenatal Cocaine Exposure Respond to Experimental Social Provocation with Escape Not Aggression

PubMed Central

Greenwald, M.K.; Chiodo, L.M.; Hannigan, J.H.; Sokol, R.J.; Janisse, J.; Delaney-Black, V.

2010-01-01

Preclinical data show that, compared to no exposure, prenatal cocaine exposure (PCE) has age-dependent effects on social interaction and aggression. The aim of this clinical study was to determine how heavy/persistent PCE – after controlling for other prenatal drug exposures, sex and postnatal factors – predicts behavioral sensitivity to provocation (i.e., reactive aggression) using a well-validated human laboratory model of aggression. African American teens (mean = 14.2 yrs old) with histories of heavy/persistent PCE (maternal cocaine use ≥ 2 times/week during pregnancy, or positive maternal or infant urine/meconium test at delivery; n = 86) or none/some exposure (NON: maternal cocaine use < 2 times/week during pregnancy; n = 330) completed the Point Subtraction Aggression Paradigm. In this task, teens competed in a computer game against a fictitious opponent. There were three possible responses: (a) earn points, to exchange for money later; or (b) “aggress” against the fictitious opponent by subtracting their points; or (c) escape temporarily from point subtraction perpetrated by the fictitious opponent. The PCE group responded significantly more frequently on the escape option than the NON group, but did not differ in aggressive or money-earning responses. These data indicate that PCE-teens provoked with a social stressor exhibit a behavioral preference for escape (negative reinforcement) more than for aggressive (retaliatory) or appetitive (point- or money-reinforced) responses. These findings are consistent with preclinical data showing that social provocation of adolescent or young adult offspring after PCE is associated with greater escape behavior, inferring greater submission, social withdrawal, or anxiety, as opposed to aggressive behavior. PMID:20600841

Making Choices: Simultaneous Report and Provocative Statements, Tools for Appreciative Inquiry

ERIC Educational Resources Information Center

Nelson, Eric M.; Wright, Christine M.

2011-01-01

Many educators find that students do not participate actively in class, and are constantly seeking a variety of techniques to encourage student participation. The focus of this paper is to show how simultaneous report and provocative statements can be combined to foster appreciative inquiry, thereby, creating a learning environment with greater…

Role of motivation to respond to provocation, the social environment, and trait aggression in alcohol-related aggression.

PubMed

Tremblay, Paul F; Mihic, Ljiljana; Graham, Kathryn; Jelley, Jennifer

2007-01-01

Little attention has been paid to the motivation to respond to provocation and to the interaction between this motivation, alcohol, the drinking environment, and individual characteristics. Undergraduates at six Canadian universities (N = 1,232) read three vignettes describing conflict situations with social environmental manipulations while imagining themselves as either sober or intoxicated. Self-ratings assessed likelihood of assertive and aggressive responses and motivational indices of anger, offensiveness of the instigator's actions, and importance to respond to the provocation. Respondents also completed a measure of trait aggression. Multi-group structural equation models supported the hypothesis that perceived likelihood of reactive aggression is influenced by perceived alcohol intoxication, gender, trait aggression, social environmental factors, and motivation to respond to the provocation. In addition, a number of interactions were found among the predictors. These results provide insight into the types of factors that may influence aggression in drinking situations. Copyright 2007 Wiley-Liss, Inc.

Individual Differences in Responses to Provocation and Frequent Victimization by Peers

ERIC Educational Resources Information Center

Champion, Kelly M.; Clay, Daniel L.

2007-01-01

This study examined associations between victimization by peers and intention to respond to provocative events as a function of anger arousal and motivation to improve the situation in a cross-sectional sample of school-age children (N = 506, 260 males, 246 females). Results demonstrated that more intense anger and more retaliatory motivation were…

Hip range of motion and provocative physical examination tests reliability and agreement in asymptomatic volunteers

PubMed Central

Prather, H; Harris-Hayes, M; Hunt, D; Steger-May, K; Mathew, V; Clohisy, JC

2012-01-01

Objective The objectives of this study are the following: 1) report passive hip ROM in asymptomatic young adults, 2) report the intra-tester and inter-tester reliability of hip ROM measurements among testers of multiple disciplines, 3) report the results of provocative hip tests and tester agreement. Design descriptive epidemiology study Setting tertiary university Participants Twenty-eight young adult volunteers without musculoskeletal symptoms, history of disorder or surgery involving the lumbar spine or lower extremities were enrolled and completed the study. Methods Asymptomatic young adult volunteers completed questionnaires and were examined by two blinded examiners during a single session. The testers were physical therapists and physicians. Hip range of motion and provocative tests were completed by both examiners on each hip. Main Outcome Measurements Inter and intra-rater reliability for ROM and agreement for provocative tests was determined. Results Twenty-eight asymptomatic adults with mean age 31 years old (range 18–51 years) and mean modified Harris Hip Score of 99.5 ± 1.5 and UCLA Activity score of 8.8 ± 1.2 completed the study. Intra-rater agreement was excellent for all hip range of motion measurements, with intraclass correlation coefficients (ICCs) ranging from 0.76 to 0.97 with similar agreement if the examiner was a physical therapist or a physician. Excellent inter-rater reliability was found for hip flexion ICC 0.87 (95% CI 0.78 to 0.92), supine internal rotation ICC 0.75 (95% CI 0.60 to 0.84) and prone internal rotation ICC 0.79 (95% CI 0.66 to 0.87). The least reliable measurements were supine hip abduction (ICC 0.34) and supine external rotation (ICC 0.18). Agreement between examiners ranged from 96–100% for provocative hip tests which included the hip impingement, resisted straight leg raise, FABER/Patrick’s and log roll tests. Conclusions Specific hip ROM measures show excellent inter-rater reliability and provocative hip tests

Laboratory measurements of the effective-stress law of carbonate rocks under deformation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warpinski, N.R.; Teufel, L.W.

The behavior of rocks under the combined effects of confining stress and pore pressure is an important issue for any in situ petroleum process. In order to simplify the difficulties in dealing with two independent parameters, it is customary to introduce an effective-stress law which relates a net, or effective, stress to some combination of confining stress and pore pressure. This report documents laboratory tests of mechanical properties of five carbonate rocks.

Children's Emotion Regulation: Self-Report and Physiological Response to Peer Provocation

ERIC Educational Resources Information Center

Hessler, Danielle M.; Katz, Lynn Fainsilber

2007-01-01

The authors examined the notion that children's emotion regulation (ER) is a uniform skill by (a) investigating the concordance between self-report of ER and physiological measures and by (b) examining ER in a specific context (e.g., peer provocation) and context-free manner (e.g., during a semistructured interview of ER abilities). Seventy-two…

The Photomontages of John Heartfield: A Provocative Teaching Tool for "Landeskunde."

ERIC Educational Resources Information Center

Mathieu, Gustave Bording

1992-01-01

A case is made for the use of the politically provocative photomontages of Heartfield (a.k.a. Berlin-born Helmut Herzfeld) in the German classroom. The interplay of language, art, culture, and history makes them especially useful as realia. A model for teaching them is presented, including a chronology and nine reproductions. (Author/LB)

Laboratory determination of effective stress laws for deformation and permeability of chalk

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teufel, L W; Warpinski, N R

1990-01-01

Laboratory deformation and permeability measurements have been made on chalk samples from Ekofisk area fields as a function of confining stress and pore pressure to determine the effective stress laws for chalk. An understanding of the effective stress law is essential to obtain correct reservoir-property data from core analysis and is critical for reservoir management studies and reservoir compaction models. A powerful statistical technique known as the response surface method has been used to analyze our laboratory data determine the form of the effective stress law for deformation and permeability. Experiments were conducted on chalk samples that had a rangemore » of porosities from 15% to 36%, because porosity is the dominant intrinsic property that effects deformation and permeability behavior of chalk. Deformation of a 36% porosity chalk was highly nonlinear, but the effective stress law was linear, with {alpha} equal to about unity. Lower-porosity samples showed linear strain behavior and a linear effective stress law with {alpha} as low as 0.74. Analysis of the effective stress law for permeability is presented only for the lowest porosity chalk sample because changes in permeability in the higher-porosity chalk samples due to increasing confining stress or pore pressure were not were large enough, to deduce meaningful effective stress relationships. 15 refs., 8 figs., 2 tabs.« less

Use of Provocative Angiography to Localize Site in Recurrent Gastrointestinal Bleeding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnston, Ciaran, E-mail: ciaranjohnston@yahoo.co.uk; Tuite, David; Pritchard, Ruth

2007-09-15

Background. While the source of most cases of lower gastrointestinal bleeding may be diagnosed with modern radiological and endoscopic techniques, approximately 5% of patients remain who have negative endoscopic and radiological investigations.Clinical Problem. These patients require repeated hospital admissions and blood transfusions, and may proceed to exploratory laparotomy and intraoperative endoscopy. The personal and financial costs are significant. Method of Diagnosis and Decision Making. The technique of adding pharmacologic agents (anticoagulants, vasodilators, fibrinolytics) during standard angiographic protocols to induce a prohemorrhagic state is termed provocative angiography. It is best employed when significant bleeding would otherwise necessitate emergency surgery. Treatment. Thismore » practice frequently identifies a bleeding source (reported success rates range from 29 to 80%), which may then be treated at the same session. We report the case of a patient with chronic lower gastrointestinal hemorrhage with consistently negative endoscopic and radiological workup, who had an occult source of bleeding identified only after a provocative angiographic protocol was instituted, and who underwent succeeding therapeutic coil embolization of the bleeding vessel.« less

Reproducibility of manual pressure force on provocation of the sacroiliac joint.

PubMed

Levin, U; Nilsson-Wikmar, L; Stenström, C H; Lundeberg, T

1998-01-01

Previous studies of pain-provocation sacroiliac (SI) joint tests have revealed conflicting results. The aim of the present study was to evaluate the intra- and inter-test reliability of pressure force applied during distraction test, compression test and pressure on the apex sacralis. Seventeen physiotherapists (PTs), median age 43 years and median clinical experience 11 years, all experienced in musculoskeletal evaluation and therapy, participated in the study. Each PT performed each test on the same healthy volunteer for 20 s, on three separate occasions, at intervals of one week using a specially constructed examination table which registered pressure force. The PTs were capable of maintaining a relatively constant pressure force for 20 s. The intra-test reliability was acceptable even though there were individual differences on different occasions between those PTs who used the SI joint tests often and those who seldom or never used them. The inter-test reliability was insufficient. The findings indicate the advantage of registering pressure force as a complement for standardized methods for pain-provoking tests and when learning provocation tests, since individual variability was considerable.

Optimizing laboratory animal stress paradigms: The H-H* experimental design.

PubMed

McCarty, Richard

2017-01-01

Major advances in behavioral neuroscience have been facilitated by the development of consistent and highly reproducible experimental paradigms that have been widely adopted. In contrast, many different experimental approaches have been employed to expose laboratory mice and rats to acute versus chronic intermittent stress. An argument is advanced in this review that more consistent approaches to the design of chronic intermittent stress experiments would provide greater reproducibility of results across laboratories and greater reliability relating to various neural, endocrine, immune, genetic, and behavioral adaptations. As an example, the H-H* experimental design incorporates control, homotypic (H), and heterotypic (H*) groups and allows for comparisons across groups, where each animal is exposed to the same stressor, but that stressor has vastly different biological and behavioral effects depending upon each animal's prior stress history. Implementation of the H-H* experimental paradigm makes possible a delineation of transcriptional changes and neural, endocrine, and immune pathways that are activated in precisely defined stressor contexts. Copyright © 2016 Elsevier Ltd. All rights reserved.

Corneal epithelial barrier function after oxybuprocaine provocation in diabetics.

PubMed

Stolwijk, T R; van Best, J A; Boor, J P; Lemkes, H H; Oosterhuis, J A

1990-03-01

Corneal epithelial permeability for fluorescein was determined after provocation by a local anesthetic in 18 non-insulin-dependent diabetes mellitus (NIDDM) patients, 23 insulin-dependent diabetes mellitus (IDDM) patients, and 22 healthy controls to evaluate the corneal epithelial barrier function in diabetes. All volunteers had Oxybuprocaine instilled into one eye and saline into the other eye. The epithelial permeability values were determined by fluorophotometry, and the ratio between both eyes was calculated for each individual. The mean permeability values of the saline-instilled eyes in the diabetic patients did not differ significantly from those in the healthy controls (P greater than 0.2). The individual ratios between Oxybuprocaine- and saline-instilled eyes in the NIDDM and IDDM patients differed significantly from those in the healthy controls (mean ratios: 2.6, 1.9, and 1.0, respectively; P less than 0.002). The permeability ratios and the percentage glycosylated hemoglobin (HbAlc) were linearly correlated in the NIDDM patients but not in the IDDM patients (r = 0.73, P less than 0.001, and r = 0.09, P greater than 0.68, respectively). The results showed that the corneal epithelial barrier function in the diabetic patients was not impaired compared with that in the healthy controls. After provocation by a local anesthetic, the barrier function was impaired in the diabetic patients only.

The effect of levocabastine and furosemide pretreatment on hyperreactive response after nasal provocation with hypotonic aerosol in subjects with allergic rhinitis.

PubMed

Anzic, Srdjan Ante; Dzepina, Davor; Kalogjera, Livije

2007-11-01

Patients with allergic rhinitis demonstrate hyperreactive response in distilled water nasal provocation, shown by significant increase in nasal airway resistance (NAR). Antihistamines, including topical antihistamine, levocabastine, reduce response in non-specific nasal provocation tests. Furosemide is a diuretic which reduces hyperreactivity in lower airways, but the mode of its action is not yet fully understood. In this study, we hypothesized that either levocabastine or furosemide pre-treatment in allergic rhinitis patients reduced response to nasal challenge with non-isotonic aerosol. To test the hypothesis, we measured the effect of pre-treatment with levocabastine and furosemide in topical application on suppression of hyperreactive response to distilled water nasal inhalation. Nasal resistance was measured, prior to and after the provocation, by active anterior rhinomanometry in two randomized groups of patients, according to pre-treatment, either by levocabastine or furosemide, 20 patients in each group, respectively. Nasal airflow resistance and level of hyperreactive response considering nasal eosinophilia were tested. Significant increase in nasal resistance following provocation was found at baseline conditions (without pre-medication); pre-treatment with levocabastine and furosemide has suppressed such response. Patients with positive nasal eosinophilia showed a significantly higher increase in nasal resistance compared to those with negative smears. Furosemide has shown significantly better protective effect on nasal resistance increase in patients with positive eosinophils nasal smears. Levocabastine and furosemide pre-treatment suppress hyperreactive response to distilled water nasal provocation. Comparison of resistances (pre-treatment vs. without) showed more protective effect of furosemide, measured on both better and worse patent side of nose, in contrast to levocabastine group for which it was shown only on better patent side prior to

Scopolamine provocation-based pharmacological MRI model for testing procognitive agents.

PubMed

Hegedűs, Nikolett; Laszy, Judit; Gyertyán, István; Kocsis, Pál; Gajári, Dávid; Dávid, Szabolcs; Deli, Levente; Pozsgay, Zsófia; Tihanyi, Károly

2015-04-01

There is a huge unmet need to understand and treat pathological cognitive impairment. The development of disease modifying cognitive enhancers is hindered by the lack of correct pathomechanism and suitable animal models. Most animal models to study cognition and pathology do not fulfil either the predictive validity, face validity or construct validity criteria, and also outcome measures greatly differ from those of human trials. Fortunately, some pharmacological agents such as scopolamine evoke similar effects on cognition and cerebral circulation in rodents and humans and functional MRI enables us to compare cognitive agents directly in different species. In this paper we report the validation of a scopolamine based rodent pharmacological MRI provocation model. The effects of deemed procognitive agents (donepezil, vinpocetine, piracetam, alpha 7 selective cholinergic compounds EVP-6124, PNU-120596) were compared on the blood-oxygen-level dependent responses and also linked to rodent cognitive models. These drugs revealed significant effect on scopolamine induced blood-oxygen-level dependent change except for piracetam. In the water labyrinth test only PNU-120596 did not show a significant effect. This provocational model is suitable for testing procognitive compounds. These functional MR imaging experiments can be paralleled with human studies, which may help reduce the number of false cognitive clinical trials. © The Author(s) 2015.

Youth Offspring of Mothers with Posttraumatic Stress Disorder Have Altered Stress Reactivity in Response to a Laboratory Stressor

PubMed Central

Danielson, Carla Kmett; Hankin, Benjamin L.; Badanes, Lisa S.

2015-01-01

Summary Parental Posttraumatic Stress Disorder (PTSD), particularly maternal PTSD, confers risk for stress-related psychopathology among offspring. Altered hypothalamic-pituitary-adrenal (HPA) axis functioning is one mechanism proposed to explain transmission of this intergenerational risk. Investigation of this mechanism has been largely limited to general stress response (e.g., diurnal cortisol), rather than reactivity in response to an acute stressor. We examined cortisol reactivity in response to a laboratory stressor among offspring of mothers with a lifetime diagnosis of PTSD (n=36) and age- and gender- matched control offspring of mothers without PTSD (n=36). Youth (67% girls; mean age = 11.4, SD = 2.6) participated in a developmentally sensitive laboratory stressor and had salivary cortisol assessed five times (one pre-stress, one immediate post-stress, and three recovery measures, spaced 15 minutes apart). Results were consistent with the hypothesis that offspring of mothers with PTSD would exhibit a dysregulated, blunted cortisol reactivity profile and control offspring would display the expected adaptive peak in cortisol response to challenge profile. Findings were maintained after controlling for youth traumatic event history, physical anxiety symptoms, and depression, as well as maternal depression. This finding contributes to the existing literature indicating that attenuated HPA axis functioning, inclusive of hyposecretion of cortisol in response to acute stress, is robust among youth of mothers with PTSD. Future research is warranted in elucidating cortisol reactivity as a link between maternal PTSD and stress-related psychopathology vulnerability among offspring. PMID:25622009

Using the Universal Design for Learning Approach in Science Laboratories to Minimize Student Stress

ERIC Educational Resources Information Center

Miller, Daniel K.; Lang, Patricia L.

2016-01-01

This commentary discusses how the principles of universal design for learning (UDL) can be applied in the science laboratory with an emphasis on assisting students who experience stress in the laboratory environment. The UDL approach in the laboratory is based on three elements: open-mindedness, supportive communication, and analysis and…

The Novaco Anger Scale--Provocation Inventory (1994 Version) in Dutch Forensic Psychiatric Patients

ERIC Educational Resources Information Center

Hornsveld, Ruud H. J.; Muris, Peter; Kraaimaat, Floris W.

2011-01-01

We examined the psychometric properties of the Novaco Anger Scale--Provocation Inventory (NAS-PI, 1994 version) in Dutch violent forensic psychiatric patients and secondary vocational students. A confirmatory factor analysis of the subscale structure of the NAS was carried out, reliability was investigated, and relations were calculated between…

Hit or Run: Exploring Aggressive and Avoidant Reactions to Interpersonal Provocation Using a Novel Fight-or-Escape Paradigm (FOE).

PubMed

Beyer, Frederike; Buades-Rotger, Macià; Claes, Marie; Krämer, Ulrike M

2017-01-01

Interpersonal provocation presents an approach-avoidance conflict to the provoked person: responding aggressively might yield the joy of retribution, whereas withdrawal can provide safety. Experimental aggression studies typically measure only retaliation intensity, neglecting whether individuals want to confront the provocateur at all. To overcome this shortcoming of previous measures, we developed and validated the Fight-or-Escape paradigm (FOE). The FOE is a competitive reaction time (RT) task in which the winner can choose the volume of a sound blast to be directed at his/her opponent. Participants face two ostensible opponents who consistently select either high or low punishments. At the beginning of each trial, subjects are given the chance to avoid the encounter for a limited number of times. In a first experiment ( n = 27, all women), we found that fear potentiation (FP) of the startle response was related to lower scores in a composite measure of aggression and avoidance against the provoking opponent. In a second experiment ( n = 34, 13 men), we altered the paradigm such that participants faced the opponents in alternating rather than in random order. Participants completed the FOE as well as the Dot-Probe Task (DPT) and the Approach-Avoidance Task (AAT). Subjects with higher approach bias scores in the AAT avoided the provoking opponent less frequently. Hence, individuals with high threat reactivity and low approach motivation displayed more avoidant responses to provocation, whereas participants high in approach motivation were more likely to engage in aggressive interactions when provoked. The FOE is thus a promising laboratory measure of avoidance and aggression.

Hit or Run: Exploring Aggressive and Avoidant Reactions to Interpersonal Provocation Using a Novel Fight-or-Escape Paradigm (FOE)

PubMed Central

Beyer, Frederike; Buades-Rotger, Macià; Claes, Marie; Krämer, Ulrike M.

2017-01-01

Interpersonal provocation presents an approach-avoidance conflict to the provoked person: responding aggressively might yield the joy of retribution, whereas withdrawal can provide safety. Experimental aggression studies typically measure only retaliation intensity, neglecting whether individuals want to confront the provocateur at all. To overcome this shortcoming of previous measures, we developed and validated the Fight-or-Escape paradigm (FOE). The FOE is a competitive reaction time (RT) task in which the winner can choose the volume of a sound blast to be directed at his/her opponent. Participants face two ostensible opponents who consistently select either high or low punishments. At the beginning of each trial, subjects are given the chance to avoid the encounter for a limited number of times. In a first experiment (n = 27, all women), we found that fear potentiation (FP) of the startle response was related to lower scores in a composite measure of aggression and avoidance against the provoking opponent. In a second experiment (n = 34, 13 men), we altered the paradigm such that participants faced the opponents in alternating rather than in random order. Participants completed the FOE as well as the Dot-Probe Task (DPT) and the Approach-Avoidance Task (AAT). Subjects with higher approach bias scores in the AAT avoided the provoking opponent less frequently. Hence, individuals with high threat reactivity and low approach motivation displayed more avoidant responses to provocation, whereas participants high in approach motivation were more likely to engage in aggressive interactions when provoked. The FOE is thus a promising laboratory measure of avoidance and aggression. PMID:29089875

In Search of the Trauma Memory: A Meta-Analysis of Functional Neuroimaging Studies of Symptom Provocation in Posttraumatic Stress Disorder (PTSD)

PubMed Central

Sartory, Gudrun; Cwik, Jan; Knuppertz, Helge; Schürholt, Benjamin; Lebens, Morena; Seitz, Rüdiger J.; Schulze, Ralf

2013-01-01

Notwithstanding some discrepancy between results from neuroimaging studies of symptom provocation in posttraumatic stress disorder (PTSD), there is broad agreement as to the neural circuit underlying this disorder. It is thought to be characterized by an exaggerated amygdalar and decreased medial prefrontal activation to which the elevated anxiety state and concomitant inadequate emotional regulation are attributed. However, the proposed circuit falls short of accounting for the main symptom, unique among anxiety disorders to PTSD, namely, reexperiencing the precipitating event in the form of recurrent, distressing images and recollections. Owing to the technical demands, neuroimaging studies are usually carried out with small sample sizes. A meta-analysis of their findings is more likely to cast light on the involved cortical areas. Coordinate-based meta-analyses employing ES-SDM (Effect Size Signed Differential Mapping) were carried out on 19 studies with 274 PTSD patients. Thirteen of the studies included 145 trauma-exposed control participants. Comparisons between reactions to trauma-related stimuli and a control condition and group comparison of reactions to the trauma-related stimuli were submitted to meta-analysis. Compared to controls and the neutral condition, PTSD patients showed significant activation of the mid-line retrosplenial cortex and precuneus in response to trauma-related stimuli. These midline areas have been implicated in self-referential processing and salient autobiographical memory. PTSD patients also evidenced hyperactivation of the pregenual/anterior cingulate gyrus and bilateral amygdala to trauma-relevant, compared to neutral, stimuli. Patients showed significantly less activation than controls in sensory association areas such as the bilateral temporal gyri and extrastriate area which may indicate that the patients’ attention was diverted from the presented stimuli by being focused on the elicited trauma memory. Being involved in

Technological change and the medical technologist: a stress survey of four biomedical laboratories in a large tertiary care hospital.

PubMed

Yassi, A; Miller, B

1990-01-01

Medical technologists from four clinical laboratories in a large teaching hospital were surveyed for their perceptions of occupational stress or job dissatisfaction concomitant with the advent of major technological and procedural change. Overall the data support the interpretation of excessive stress and job dissatisfaction. More than one-third (37.7%) of the laboratory personnel experienced psychological symptoms of occupational stress; 46.4% had experienced physical symptoms of stress. There was a marked and significant increase in reports of adverse effects among the group of laboratory workers subjected to the most extensive technological changes. Main components of the stress difference related to work overload, feelings of uncertainty in the face of new technology, lack of direction from supervisors and lack of influence on management. Age, type of shift worked and years of employment were associated with physical and psychological manifestations of stress. Implications and recommendations for laboratory workers, hospital administrators and educators are discussed.

Experimental panic provocation in healthy man—a translational role in anti-panic drug development?

PubMed Central

Kellner, Michael

2011-01-01

Experimental neurochemical provocation of panic attacks in susceptible human subjects has considerably expanded our knowledge of the pathophysiology and psychopharmacology of panic disorder. Some panicogens also elicit short-lived panic-like states in healthy man. This offers the opportunity to assess the anti-panic action of drugs in proof-of-concept studies. However, from current data it is still unclear whether experimental panic in healthy man is a valid translational model. Most such studies in healthy volunteers have been performed using a cholecystokinin tetrapeptide (CCK-4) challenge. While CCK-4 panic was blocked by alprazolam pretreatment, escitalopram showed negative results in healthy man. Preliminary findings on novel investigational drugs and a few problematic results will be reviewed. Small sample sizes in many panic provocation studies, lack of dose-response aspects, and still-insufficient knowledge about the biological underpinning of experimental and spontaneous panic limit the interpretation of existing findings and should inspire further research. PMID:22275853

Intimate partner violence perpetration corresponds to a dorsal-ventral gradient in medial PFC reactivity to interpersonal provocation.

PubMed

Chester, David S; DeWall, C Nathan

2018-01-22

Intimate partner violence (IPV) perpetration is often preceded by perceived interpersonal provocations such as slights, insults, and rejections. Yet the neural mechanisms that link provocation to IPV remain unclear. In the context of interactions with strangers, the medial prefrontal cortex (MPFC) has been repeatedly shown to respond to provocation, with more dorsal activation associated with more aggressive reactions and more ventral activation associated with less aggressive reactions. We used functional brain imaging to test whether this dorsal-ventral MPFC reactivity gradient would also correlate with greater aggression towards an unexamined target: intimate partners. To do so, 61 undergraduates (27.87% male, age range: 18-22) reported whether they had ever committed various acts of IPV perpetration (e.g., punching, hitting, shoving) and then were repeatedly provoked by a stranger while undergoing functional MRI (fMRI) scanning. Individuals with a disproportionately dorsal, rather than ventral, MPFC response were more likely to have perpetrated IPV and had perpetrated more kinds of IPV, even when controlling for gender. These findings provide further evidence that the dorsal-ventral MPFC gradient is a critical, biological indicator of whether an individual is more or less likely to react aggressively and suggest new avenues for understanding and potentially preventing IPV perpetration.

Children's Moral Reasoning about Family and Peer Violence: The Role of Provocation and Retribution.

ERIC Educational Resources Information Center

Astor, Ron A.

1994-01-01

Examined violent and nonviolent inner-city children's moral reasoning about violence in family and peer situations. All of the children condemned unprovoked violence. With provoked situations, the violent group focused more on the immorality of the provocation and perceived force akin to reciprocal justice, whereas the nonviolent group perceived…

On recent advances in human engineering Provocative trends in embryology, genetics, and regenerative medicine.

PubMed

Anton, Roman

2016-01-01

Advances in embryology, genetics, and regenerative medicine regularly attract attention from scientists, scholars, journalists, and policymakers, yet implications of these advances may be broader than commonly supposed. Laboratories culturing human embryos, editing human genes, and creating human-animal chimeras have been working along lines that are now becoming intertwined. Embryogenic methods are weaving traditional in vivo and in vitro distinctions into a new "in vivitro" (in life in glass) fabric. These and other methods known to be in use or thought to be in development promise soon to bring society to startling choices and discomfiting predicaments, all in a global effort to supply reliably rejuvenating stem cells, to grow immunologically non-provocative replacement organs, and to prevent, treat, cure, or even someday eradicate diseases having genetic or epigenetic mechanisms. With humanity's human-engineering era now begun, procedural prohibitions, funding restrictions, institutional controls, and transparency rules are proving ineffective, and business incentives are migrating into the most basic life-sciences inquiries, wherein lie huge biomedical potentials and bioethical risks. Rights, health, and heritage are coming into play with bioethical presumptions and formal protections urgently needing reassessment.

The value and safety of specific nasal provocation in the diagnosis of allergic rhinitis in mild persistent asthma under inhaled steroid therapy.

PubMed

Tuskan, Tansu Cengiz; Gemicioglu, Bilun; Ikitimur, Hande; Yilmaz, Nail; Tuskan, Kemal; Oz, Ferhan; Can, Gunay

2010-01-01

Although specific nasal provocation is an objective diagnostic test for allergic rhinitis, it can also increase the lower airway responsiveness in asthmatic patients. Our goal was to determine the value and safety of specific nasal provocation test for the diagnosis of allergic rhinitis in mild persistent asthmatic patients under low-dose inhaled steroid therapy. The study was performed on 32 mild persistent, stable, mite-sensitive allergic asthmatics (group 1), 9 mild persistent nonallergic asthmatics (group 2) and 9 healthy non-smokers (group 3). Nasal symptoms were noted, paranasal sinus computerized tomography (PNCT) and rhinoscopic evaluations were performed. Cases with pathologic-anatomic changes in PNCT and rhinoscopy were excluded. Symptom scoring, flow-volume, peak expiratory flow (PEF), serum and nasal lavage eosinophil cationic protein (ECP) and nasal lavage eosinophil counts were performed before mite specific nasal provocation test and at the 0th, 4th and 24th hours following the test. No adverse effects were observed in all diagnostic procedures. Total diagnostic value of nasal symptoms were found to be at 92%, while being 70% for rhinoscopy and 88% for specific nasal provocation test respectively in the diagnosis of allergic rhinitis in group 1. Statistically significant differences were found between basal nasal lavage eosinophil values (p < 0.001) and ECP levels (p < 0.05) when group 1 was compared with both group 2 and group 3. In the remaining measured values between three groups, no statistically significant differences were found. Specific nasal provocation test is a safe method for mild house dust mite allergic asthma cases under low-dose inhaled steroid therapy, but history of rhinitis might be sufficient for the diagnosis of allergic rhinitis.

Cortisol stress resonance in the laboratory is associated with inter-couple diurnal cortisol covariation in daily life.

PubMed

Engert, Veronika; Ragsdale, Amy M; Singer, Tania

2018-02-01

In laboratory environments individuals may display empathic cortisol stress responses merely from observing another experience psychosocial stress. Moreover, within couples, women synchronize their own to their partners' stress-induced cortisol release. We investigated whether a woman's tendency to experience such cortisol stress resonance in a controlled laboratory task is associated with the degree to which her and her partner's diurnal cortisol levels covary in a naturalistic environment. Such habitual cortisol covariation may be a pathway via which close relationships influence health outcomes. Forty-four men completed the Trier Social Stress Test while their female partners observed the situation, either via "real-life" (one-way mirror) or "virtual" (video) observation modality. Later, the couples collected diurnal cortisol samples over two weekdays. Hierarchical linear modeling indicated that the degree to which couples covaried in their daily cortisol secretion was associated with the female partner's cortisol stress resonance in the laboratory, and that this association was stronger if stress resonance was assessed in the "real-life" observation condition. Specifically, women with higher cortisol stress resonance were more closely linked to their partner's diurnal cortisol secretion. Neither momentary partner presence during sampling nor relationship duration or quality accounted for the association. By showing that covariation in the laboratory has ecological validity in naturalistic conditions, these results make an important methodological contribution to the study of dyadic processes. Given that close relationships exert immense influence over individual health outcomes, understanding the association between acute and chronic physiological linkage may provide important insight into the mechanisms by which close relationships impact well-being. Copyright © 2018 Elsevier Inc. All rights reserved.

Psychosocial stress based on public speech in humans: is there a real life/laboratory setting cross-adaptation?

PubMed

Jezova, D; Hlavacova, N; Dicko, I; Solarikova, P; Brezina, I

2016-07-01

Repeated or chronic exposure to stressors is associated with changes in neuroendocrine responses depending on the type, intensity, number and frequency of stress exposure as well as previous stress experience. The aim of the study was to test the hypothesis that salivary cortisol and cardiovascular responses to real-life psychosocial stressors related to public performance can cross-adapt with responses to psychosocial stress induced by public speech under laboratory setting. The sample consisted of 22 healthy male volunteers, which were either actors, more precisely students of dramatic arts or non-actors, students of other fields. The stress task consisted of 15 min anticipatory preparation phase and 15 min of public speech on an emotionally charged topic. The actors, who were accustomed to public speaking, responded with a rise in salivary cortisol as well as blood pressure to laboratory public speech. The values of salivary cortisol, systolic blood pressure and state anxiety were lower in actors compared to non-actors. Unlike non-actors, subjects with experience in public speaking did not show stress-induced rise in the heart rate. Evaluation of personality traits revealed that actors scored significantly higher in extraversion than the subjects in the non-actor group. In conclusion, neuroendocrine responses to real-life stressors in actors can partially cross-adapt with responses to psychosocial stress under laboratory setting. The most evident adaptation was at the level of heart rate responses. The public speech tasks may be of help in evaluation of the ability to cope with stress in real life in artists by simple laboratory testing.

Bronchial provocation tests in clinical practice.

PubMed

Borges, Marcos de Carvalho; Ferraz, Erica; Vianna, Elcio Oliveira

2011-01-01

Bronchial hyperresponsiveness, which consists of an exaggerated response of the airways to bronchoconstrictor stimuli, is one of the main characteristics of asthma, presented in nearly all asthmatic patients. Bronchial hyperresponsiveness may also be present in other diseases, such as allergic rhinitis, chronic obstructive pulmonary disease, cystic fibrosis, heart failure and respiratory infection, and with some medications, such as β-blockers. Bronchial provocation tests (also known as bronchial challenges) are used to evaluate bronchial responsiveness. These tests have become increasingly used over the last 20 years, with the development and validation of accurate, safe and reproducible tests, and with the publication of well-detailed protocols. Several stimuli can be used in a bronchial challenge, and they are classified as direct and indirect stimuli. There are many indications for a bronchial challenge. In this review, we discuss the main differences between direct and indirect stimuli, and the use of bronchial challenges in clinical practice, especially for confirming diagnoses of asthma, exercise-induced bronchoconstriction and cough-variant asthma, and for use among elite-level athletes.

Mobile kidney pain provocation ultrasonography before surgery for symptomatic mobile kidney: A prospective study of 43 consecutive patients.

PubMed

Arnerlöv, Conny; Söderström, Minette; Öhberg, Lars

2016-01-01

The aim of this study was to evaluate whether mobile kidney pain provocation ultrasonography together with intravenous pyelography in supine and standing positions and a full medical history can confirm the diagnosis of the clinical condition of symptomatic mobile kidney and aid the selection of patients for surgical treatment. In a consecutive study, 43 patients with the clinical picture of symptomatic mobile kidney, a positive mobile kidney pain provocation ultrasonography and a renal descent of at least 2 lumbar vertebral heights on intravenous pyelography in the standing position, were operated on with nephropexy. Patients' pain relief after nephropexy was evaluated by clinical follow-up, a questionnaire and visual analogue scale (VAS) scoring. Reduction of pain after nephropexy was associated with a significant decrease in VAS scoring from a median of 8 (range 4-10) preoperatively to a median of 0 (range 0-7) postoperatively (p < 0.001). Thirty-four patients (79%) were cured of their pain and seven patients (16%) experienced substantial relief from their pain symptoms. In two patients (5%) the symptoms were unchanged. The results indicate that mobile kidney pain provocation ultrasonography and intravenous pyelography in supine and standing positions can verify the diagnosis of symptomatic mobile kidney and aid the selection of patients who will benefit from nephropexy.

Stress responding in cannabis smokers as a function of trauma exposure, sex, and relapse in the human laboratory.

PubMed

Chao, Thomas; Radoncic, Vanya; Hien, Denise; Bedi, Gillinder; Haney, Margaret

2018-04-01

Stress responding is linked to drug use, but little is known about stress responses in cannabis smokers. We investigated acute stress responding in cannabis smokers as a function of trauma exposure and sex, and relationships between stress responses and cannabis relapse. 125 healthy, non-treatment-seeking daily cannabis smokers (23F, 102 M) completed the Trier Social Stress Task (TSST), a standardized laboratory stressor; subsets also completed a trauma questionnaire (n = 106) and a laboratory cannabis relapse measure (n = 54). Stress responding was assessed with heart rate (HR), salivary cortisol (CORT), and self-rated mood. Cannabis smokers reporting at least one trauma exposure had higher CORT and anxiety overall compared to those reporting no trauma. Stress responding did not differ as a function of binary trauma exposure, although total number of exposures correlated positively with CORT and anxiety during stress. Females reported increased nervousness after stress relative to males matched to the females for cannabis and cigarette use. An interactive effect of sex and trauma on HR suggested that females with trauma exposure have increased cardiovascular stress responding relative to those without such exposure, with no differential effect in males. Stress responding did not predict laboratory cannabis relapse. We report differences in acute stress responding as a function of trauma, sex, and their interaction in a large sample of relatively homogenous cannabis smokers. Further investigation of how trauma impacts stress responding in male and female cannabis smokers, and how this relates to different aspects of cannabis use, is warranted. Copyright © 2018 Elsevier B.V. All rights reserved.

Stress-dependent elastic properties of shales—laboratory experiments at seismic and ultrasonic frequencies

NASA Astrophysics Data System (ADS)

Szewczyk, Dawid; Bauer, Andreas; Holt, Rune M.

2018-01-01

Knowledge about the stress sensitivity of elastic properties and velocities of shales is important for the interpretation of seismic time-lapse data taken as part of reservoir and caprock surveillance of both unconventional and conventional oil and gas fields (e.g. during 4-D monitoring of CO2 storage). Rock physics models are often developed based on laboratory measurements at ultrasonic frequencies. However, as shown previously, shales exhibit large seismic dispersion, and it is possible that stress sensitivities of velocities are also frequency dependent. In this work, we report on a series of seismic and ultrasonic laboratory tests in which the stress sensitivity of elastic properties of Mancos shale and Pierre shale I were investigated. The shales were tested at different water saturations. Dynamic rock engineering parameters and elastic wave velocities were examined on core plugs exposed to isotropic loading. Experiments were carried out in an apparatus allowing for static-compaction and dynamic measurements at seismic and ultrasonic frequencies within single test. For both shale types, we present and discuss experimental results that demonstrate dispersion and stress sensitivity of the rock stiffness, as well as P- and S-wave velocities, and stiffness anisotropy. Our experimental results show that the stress-sensitivity of shales is different at seismic and ultrasonic frequencies, which can be linked with simultaneously occurring changes in the dispersion with applied stress. Measured stress sensitivity of elastic properties for relatively dry samples was higher at seismic frequencies however, the increasing saturation of shales decreases the difference between seismic and ultrasonic stress-sensitivities, and for moist samples stress-sensitivity is higher at ultrasonic frequencies. Simultaneously, the increased saturation highly increases the dispersion in shales. We have also found that the stress-sensitivity is highly anisotropic in both shales and that in

Seasonal variation of the impact of a stressful procedure on open field behaviour and blood corticosterone in laboratory mice.

PubMed

Meyer, L; Caston, J; Mensah-Nyagan, A G

2006-02-28

Behavioural and hormonal seasonal changes are well documented in various vertebrate species living in their natural environment but circannual variations that may occur in laboratory animals reared in standard conditions are poorly investigated. This study shows that, in laboratory mice, the effects of stress on behavioural inhibition, investigatory behaviour and blood concentration of corticosterone are seasonally dependent. No consistency was observed between the reactivity of biological structures controlling the hormonal response to stress and the behavioural activities investigated at every period of the year. During the spring time, stress, which elicited a decrease of investigatory behaviour (estimated by the walking time in an open field), increased behavioural inhibition (estimated by the percentage of walking in the central area of the open field) as well as the blood corticosterone concentration in laboratory mice. In autumn, stress had no significant effect on behaviour despite the great hormonal concentration increase. The results reveal that, at certain period of the year, a stressful procedure is unable to affect behavioural parameters in laboratory mice which were maintained in constant 12-h dark/12-h light cycle. The report constitutes a novel piece of information suggesting a potential role of the endogenous biological clock in the modulation of stress response in mammals.

Psychophysiological responses to anger provocation among Asian Indian and White men.

PubMed

Suchday, Sonia; Larkin, Kevin T

2004-01-01

To examine cultural differences in response to anger provocation, affective, cognitive, behavioral, and cardiovascular responses to social confrontation, role plays were measured in 20 Indian male immigrants in the United States and 40 White men. Participants engaged in 2 interactions with a nonacquiescent male confederate and were instructed to suppress or express their anger in counterbalanced order. Following each role play, participants state anger, and resentful and reflective cognitions pertaining to anger were assessed. Participants' videotaped behavioral responses were assessed for problem-solving skills and negative and positive verbal and nonverbal behaviors. Blood pressure and heart rate (HR) responses were recorded throughout the session. Results revealed that Indian participants used more introspective strategies comprising of repression and rational coping self-statements to anger provocation than their White counterparts. White participants experienced significantly higher HR responses and showed more awareness of physiological sensation compared to the Indian participants, but only when asked to exhibit their anger. Indian participants had a faster diastolic blood pressure (DBP) recovery when allowed to engage in anger inhibition (which is a culturally determined mode of functioning) compared to when they had to exhibit anger before inhibiting it. White men showed a heightened cardiac response to anger expression, something not seen among Indian men. Indian men, in contrast, exhibited delayed DBP recovery from anger expression and increased introspective cognitive strategies when asked to engage in anger exhibition, a behavior not congruent with their culture of origin.

Standing Vs Supine; Does it Matter in Cough Stress Testing?

PubMed

Patnam, Radhika; Edenfield, Autumn L; Swift, Steven E

The aim of this study was to compare the sensitivity of cough stress test in the standing versus supine position in the evaluation of incontinent females. We performed a prospective observational study of women with the chief complaint of urinary incontinence (UI) undergoing a provocative cough stress test (CST). Subjects underwent both a standing and a supine CST. Testing order was randomized via block randomization. Cough stress test was performed in a standard method via backfill of 200 mL or until the subject described strong urge. The subjects were asked to cough, and the physician documented urine leakage by direct observation. The gold standard for stress UI diagnosis was a positive CST in either position. Sixty subjects were enrolled, 38 (63%) tested positive on any CST, with 38 (63%) positive on standing compared with 29 (28%) positive on supine testing. Nine women (15%) had positive standing and negative supine testing. No subjects had negative standing with positive supine testing. There were no significant differences in positive tests between the 2 randomized groups (standing first and supine second vs. supine first and standing second). When compared with the gold standard of any positive provocative stress test, the supine CST has a sensitivity of 76%, whereas the standing CST has a sensitivity of 100%. The standing CST is more sensitive than the supine CST and should be performed in any patient with a complaint of UI and negative supine CST. The order of testing either supine or standing first does not affect the results.

Ondansetron and promethazine have differential effects on hypothermic responses to lithium chloride administration and to provocative motion in rats

PubMed Central

Guimaraes, Drielle D; Andrews, Paul L R; Rudd, John A; Braga, Valdir A; Nalivaiko, Eugene

2015-01-01

We recently reported that provocative motion (rotation in a home cage) causes hypothermic responses in rats, similar to the hypothermic responses associated with motion sickness in humans. Many stimuli inducing emesis in species with an emetic reflex also provoke hypothermia in the rat, therefore we hypothesized that a fall in body temperature may reflect a “nausea-like” state in these animals. As rats do not possess an emetic reflex, we employed a pharmacological approach to test this hypothesis. In humans, motion- and chemically-induced nausea have differential sensitivity to anti-emetics. We thus tested whether the hypothermia induced in rats by provocative motion (rotation at 0.7 Hz) and by the emetic LiCl (63 mg/kg i.p.) have a similar differential pharmacological sensitivity. Both provocations caused a comparable robust fall in core body temperature (−1.9 ± 0.3°C and −2.0 ± 0.2°C for chemical and motion provocations, respectively). LiCl−induced hypothermia was completely prevented by ondansetron (2mg/kg, i.p., a 5-HT3 receptor antagonist that reduces cancer chemotherapy-induced nausea and vomiting), but was insensitive to promethazine (10 mg/kg, i.p., a predominantly histamine-H1 and muscarinic receptor antagonist that is commonly used to treat motion sickness). Conversely, motion-induced hypothermia was unaffected by ondansetron but promethazine reduced the rate of temperature decline from 0.20 ± 0.02 to 0.11 ± 0.03°C/min (P < 0.05) with a trend to decrease the magnitude. We conclude that this differential pharmacological sensitivity of the hypothermic responses of vestibular vs. chemical etiology in rats mirrors the observations in other pre-clinical models and humans, and thus supports the idea that a “nausea-like” state in rodents is associated with disturbances in thermoregulation. PMID:27227074

Neural and Behavioral Correlates of Alcohol-Induced Aggression Under Provocation

PubMed Central

Gan, Gabriela; Sterzer, Philipp; Marxen, Michael; Zimmermann, Ulrich S; Smolka, Michael N

2015-01-01

Although alcohol consumption is linked to increased aggression, its neural correlates have not directly been studied in humans so far. Based on a comprehensive neurobiological model of alcohol-induced aggression, we hypothesized that alcohol-induced aggression would go along with increased amygdala and ventral striatum reactivity and impaired functioning of the prefrontal cortex (PFC) under alcohol. We measured neural and behavioral correlates of alcohol-induced aggression in a provoking vs non-provoking condition with a variant of the Taylor aggression paradigm (TAP) allowing to differentiate between reactive (provoked) and proactive (unprovoked) aggression. In a placebo-controlled cross-over design with moderate alcohol intoxication (~0.6 g/kg), 35 young healthy adults performed the TAP during functional magnetic resonance imaging (fMRI). Analyses revealed that provoking vs non-provoking conditions and alcohol vs placebo increased aggression and decreased brain responses in the anterior cingulate cortex/dorso-medial PFC (provokingprovocation interaction). However, investigation of inter-individual differences revealed (1) that pronounced alcohol-induced proactive aggression was linked to higher levels of aggression under placebo, and (2) that pronounced alcohol-induced reactive aggression was related to increased amygdala and ventral striatum reactivity under alcohol, providing evidence for their role in human alcohol-induced reactive aggression. Our findings suggest that in healthy young adults a liability for alcohol-induced aggression in a non-provoking context might depend on overall high levels of aggression, but on alcohol-induced increased striatal and amygdala reactivity when triggered by provocation. PMID:25971590

Experimental provocation of 'ice-cream headache' by ice cubes and ice water.

PubMed

Mages, Stephan; Hensel, Ole; Zierz, Antonia Maria; Kraya, Torsten; Zierz, Stephan

2017-04-01

Background There are various studies on experimentally provoked 'ice-cream headache' or 'headache attributed to ingestion or inhalation of a cold stimulus' (HICS) using different provocation protocols. The aim of this study was to compare two provocation protocols. Methods Ice cubes pressed to the palate and fast ingestion of ice water were used to provoke HICS and clinical features were compared. Results The ice-water stimulus provoked HICS significantly more often than the ice-cube stimulus (9/77 vs. 39/77). Ice-water-provoked HICS had a significantly shorter latency (median 15 s, range 4-97 s vs. median 68 s, range 27-96 s). There was no difference in pain localisation. Character after ice-cube stimulation was predominantly described as pressing and after ice-water stimulation as stabbing. A second HICS followed in 10/39 (26%) of the headaches provoked by ice water. Lacrimation occurred significantly more often in volunteers with than in those without HICS. Discussion HICS provoked by ice water was more frequent, had a shorter latency, different pain character and higher pain intensity than HICS provoked by ice cubes. The finding of two subsequent HICS attacks in the same volunteers supports the notion that two types of HICS exist. Lacrimation during HICS indicates involvement of the trigeminal-autonomic reflex.

Children's responses to hypothetical provocation by peers: coordination of assertive and aggressive strategies.

PubMed

Dirks, Melanie A; Suor, Jennifer H; Rusch, Dana; Frazier, Stacy L

2014-10-01

Children often respond to aggression by peers with assertive bids or aggressive retaliation. Little is known, however, about whether and how children coordinate these strategies across different types of provocation. The present study examined endorsement of aggressive and assertive responses to hypothetical physical, relational, and verbal provocation in a sample of lower-income children (N = 402, M age = 10.21, SD = 1.46). Latent-profile analysis revealed 3-class models for both aggression and assertion, each reflecting low, moderate, and high levels of endorsement. There was no association between children's reported use of aggression and assertion. For example, children who endorsed high levels of aggression were equally likely to be classified as low, moderate, or high on assertive responding. For both assertion and aggression, parental ratings of children's externalizing behavior and social skills differed across the low and high groups. No such differences were found between the low and moderate groups, despite the latter groups endorsing markedly higher levels of assertive and aggressive responses. This pattern of findings may be due, in part, to the situation specificity of children's responding. Our findings hint at the complexity of children's behavioral repertoires and contribute to a growing literature that suggests the need for intervention models that consider both social skills and social situations.

[Safety and efficacy of a new preservative-free levocabastine ophthalmic solution (Levofree®) using the conjunctival provocation test].

PubMed

Allaire, C; Siou-Mermet, R; Bassols, A

2012-09-01

To evaluate the safety and efficacy of preservative-free levocabastine 0.05 % ophthalmic solution compared to placebo (vehicle) and to preserved levocabastine 0.05 % ophthalmic suspension in the prevention of allergic conjunctivitis induced by a conjunctival provocation test. Ninety-two subjects (18-50 years) with a previous history of allergic conjunctivitis to pollen were randomised to receive either preservative-free levocabastine solution in one eye and preserved levocabastine suspension in the fellow eye (n=69), or preservative-free levocabastine in one eye and placebo in the fellow eye (n=23). One drop of each product was administered 10 minutes (visit 3) and 4 hours (visit 4) prior to the provocation test. The primary efficacy criterion was the sum of the itching and conjunctival hyperemia scores assessed at 3, 5 and 10 minutes after the provocation test. The safety evaluation included adverse events, visual acuity, intra-ocular pressure and study drug drop sensation. The efficacy of the preservative-free solution was significantly higher than that of placebo at all time points (P≤0.01) with one exception at visit 4 (3 minutes after the provocation test). It was significantly higher than that of the preserved suspension at visit 3, and equivalent at visit 4. The incidence of adverse events was lower with the preservative-free solution than with the preserved suspension. 94.2 % and 95.7 % subjects rated preservative-free levocabastine drop sensation as "good" or "very good" at visits 3 and 4 respectively, whereas these rates were 68.1 % and 63.8 % with preserved levocabastine. This difference between the two formulations was highly statistically significant (P<0.001). The efficacy of preservative-free levocabastine was superior to that of the placebo and of the preserved suspension at visit 3, at least as effective as the preserved suspension at visit 4, and better tolerated at each visit. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Pro and Contra: Provocation Tests in Drug Hypersensitivity

PubMed Central

Soyer, Ozge; Sahiner, Umit Murat; Sekerel, Bulent Enis

2017-01-01

Drug provocation test (DPT) is the controlled administration of a drug to diagnose immune- or non-immune-mediated drug hypersensitivity and the last step for accurate recognition of drug hypersensitivity reactions when the previous diagnostic evaluations are negative or unavailable. A DPT is performed only if other conventional tests fail to yield conclusive results. In each clinical presentation, “to provoke or not to provoke” a patient should be decided after careful assessment of the risk–benefit ratio. Well-defined benefits of DPT include confirmative exclusion of diagnoses of drug hypersensitivity and provision of safe alternatives. However, disadvantages such as safety, difficulty in interpretations of results, lack of objective biomarkers, risks of resensitization, efficiency in daily practice, and lack of standardized protocols, are poorly debated. This review summarizes the current published research concerning DPT, with particular emphasis on the advantages and disadvantages of DPT in an evidence-based manner. PMID:28677662

Re-conceptualizing stress: Shifting views on the consequences of stress and its effects on stress reactivity.

PubMed

Liu, Jenny J W; Vickers, Kristin; Reed, Maureen; Hadad, Marilyn

2017-01-01

The consequences of stress are typically regarded from a deficit-oriented approach, conceptualizing stress to be entirely negative in its outcomes. This approach is unbalanced, and may further hinder individuals from engaging in adaptive coping. In the current study, we explored whether negative views and beliefs regarding stress interacted with a stress framing manipulation (positive, neutral and negative) on measures of stress reactivity for both psychosocial and physiological stressors. Ninety participants were randomized into one of three framing conditions that conceptualized the experience of stress in balanced, unbalanced-negative or unbalanced-positive ways. After watching a video on stress, participants underwent a psychosocial (Trier Social Stress Test), or a physiological (CO2 challenge) method of stress-induction. Subjective and objective markers of stress were assessed. Most of the sampled population regarded stress as negative prior to framing. Further, subjective and objective reactivity were greater to the TSST compared to the CO2 challenge. Additionally, significant cubic trends were observed in the interactions of stress framing and stress-induction methodologies on heart rate and blood pressure. Balanced framing conditions in the TSST group had a significantly larger decrease in heart rate and diastolic blood pressure following stress compared to the positive and negative framing conditions. Findings confirmed a deficit-orientation of stress within the sampled population. In addition, results highlighted the relative efficacy of the TSST compared to CO2 as a method of stress provocation. Finally, individuals in framing conditions that posited stress outcomes in unbalanced manners responded to stressors less efficiently. This suggests that unbalanced framing of stress may have set forth unrealistic expectations regarding stress that later hindered individuals from adaptive responses to stress. Potential benefits of alternative conceptualizations

Re-conceptualizing stress: Shifting views on the consequences of stress and its effects on stress reactivity

PubMed Central

Liu, Jenny J. W.

2017-01-01

Background The consequences of stress are typically regarded from a deficit-oriented approach, conceptualizing stress to be entirely negative in its outcomes. This approach is unbalanced, and may further hinder individuals from engaging in adaptive coping. In the current study, we explored whether negative views and beliefs regarding stress interacted with a stress framing manipulation (positive, neutral and negative) on measures of stress reactivity for both psychosocial and physiological stressors. Method Ninety participants were randomized into one of three framing conditions that conceptualized the experience of stress in balanced, unbalanced-negative or unbalanced-positive ways. After watching a video on stress, participants underwent a psychosocial (Trier Social Stress Test), or a physiological (CO2 challenge) method of stress-induction. Subjective and objective markers of stress were assessed. Results Most of the sampled population regarded stress as negative prior to framing. Further, subjective and objective reactivity were greater to the TSST compared to the CO2 challenge. Additionally, significant cubic trends were observed in the interactions of stress framing and stress-induction methodologies on heart rate and blood pressure. Balanced framing conditions in the TSST group had a significantly larger decrease in heart rate and diastolic blood pressure following stress compared to the positive and negative framing conditions. Conclusion Findings confirmed a deficit-orientation of stress within the sampled population. In addition, results highlighted the relative efficacy of the TSST compared to CO2 as a method of stress provocation. Finally, individuals in framing conditions that posited stress outcomes in unbalanced manners responded to stressors less efficiently. This suggests that unbalanced framing of stress may have set forth unrealistic expectations regarding stress that later hindered individuals from adaptive responses to stress. Potential

Reliability and validity of three pain provocation tests used for the diagnosis of chronic proximal hamstring tendinopathy.

PubMed

Cacchio, Angelo; Borra, Fabrizio; Severini, Gabriele; Foglia, Andrea; Musarra, Frank; Taddio, Nicola; De Paulis, Fosco

2012-09-01

The clinical assessment of chronic proximal hamstring tendinopathy (PHT) in athletes is a challenge to sports medicine. To be able to compare the results of research and treatments, the methods used to diagnose and evaluate PHT must be clearly defined and reproducible. To assess the reliability and validity of three pain provocation tests used for the diagnosis of PHT. Ninety-two athletes with (N=46) and without (N=46) PHT were examined by one physician and two physiotherapists, who were trained in the examination techniques before the study. The examiners were blinded to the symptoms and identity of the athletes. The three pain provocation tests examined were the Puranen-Orava, bent-knee stretch and modified bent-knee stretch tests. Intraclass correlation coefficients (ICCs) based on the repeated measures analysis of variance were used to analyse the intraexaminer and interexaminer reliability, while sensitivity, specificity, predictive values and likelihood ratios were used to determine the validity of the three tests. The ICC values in all three tests revealed a high correlation (range 0.82 to 0.88) for the interexaminer reliability and a high-to-very high correlation (range 0.87 to 0.93) for the intraexaminer reliability. All three tests displayed a moderate-to-high validity, with the highest degree of validity being yielded by the modified bent-knee stretch test. All three pain provocation tests proved to be of potential value in assessing chronic PHT in athletes. However, we recommend that they be used in conjunction with other objective measures, such as MRI.

The Consequence of Combined Pain and Stress on Work Ability in Female Laboratory Technicians: A Cross-Sectional Study.

PubMed

Jay, Kenneth; Friborg, Maria Kristine; Sjøgaard, Gisela; Jakobsen, Markus Due; Sundstrup, Emil; Brandt, Mikkel; Andersen, Lars Louis

2015-12-11

Musculoskeletal pain and stress-related disorders are leading causes of impaired work ability, sickness absences and disability pensions. However, knowledge about the combined detrimental effect of pain and stress on work ability is lacking. This study investigates the association between pain in the neck-shoulders, perceived stress, and work ability. In a cross-sectional survey at a large pharmaceutical company in Denmark 473 female laboratory technicians replied to questions about stress (Perceived Stress Scale), musculoskeletal pain intensity (scale 0-10) of the neck and shoulders, and work ability (Work Ability Index). General linear models tested the association between variables. In the multi-adjusted model, stress (p < 0.001) and pain (p < 0.001) had independent main effects on the work ability index score, and there was no significant stress by pain interaction (p = 0.32). Work ability decreased gradually with both increased stress and pain. Workers with low stress and low pain had the highest Work Ability Index score (44.6 (95% CI 43.9-45.3)) and workers with high stress and high pain had the lowest score (32.7 (95% CI 30.6-34.9)). This cross-sectional study indicates that increased stress and musculoskeletal pain are independently associated with lower work ability in female laboratory technicians.

Laboratory simulation of the effects of overburden stress on the specific storage of shallow artesian aquifers

USGS Publications Warehouse

Sepúlveda, Nicasio; Zack, A.L.; Krishna, J.H.; Quinones-Aponte, Vicente; Gomez-Gomez, Fernando; Morris, G.L.

1990-01-01

A laboratory experiment to measure the specific storage of an aquifer material was conducted. A known dead load, simulating an overburden load, was applied to a sample of completely saturated aquifer material contained inside a cylinder. After the dead load was applied, water was withdrawn from the sample, causing the hydrostatic pressure to decrease and the effective stress to increase. The resulting compression of the sample and the amount of water withdrawn were measured after equilibrium was reached. The procedure was repeated by increasing the dead load and the hydrostatic pressure followed by withdrawing water to determine new values of effective stress and compaction. The simulated dead loads are typical of those experienced by shallow artesian aquifers. The void ratio and the effective stress of the aquifer sample, as simulated by different dead loads, determine the pore volume compressibility which, in turn, determines the values of specific storage. An analytical algorithm was used to independently determine the stress dependent profile of specific storage. These values are found to be in close agreement with laboratory results. Implications for shallow artesian aquifers, with relatively small overburden stress, are also addressed.

Responses of dogs with food allergies to single-ingredient dietary provocation.

PubMed

Jeffers, J G; Meyer, E K; Sosis, E J

1996-08-01

To characterize specific food ingredients causing allergic reactions in dogs and to assess cross-reactivity between proteins derived from a single animal source or from different plant products. Prospective study. 25 dogs with histories and cutaneous signs consistent with food-allergic dermatitis. Dogs were fed a food-elimination diet until resolution of clinical signs and then challenged with their original diet. A diagnosis of food allergy was made if there was complete return of pruritus within 14 days of challenge exposure. After diagnosis, dogs were fed the food-elimination diet until signs related to dietary challenge abated. The dogs then were fed beef, chicken, chicken eggs, cows' milk, wheat, soy, and corn in single-ingredient provocation trials for 1 week. Any cutaneous reactions to these food ingredients were recorded by their owners. Beef and soy most often caused adverse cutaneous reactions, although all ingredients induced clinical signs in at least 1 dog. Mean number of allergens per dog was 2.4, with 80% reacting to 1 or 2 proteins and 64% reacting to 2 or more of the proteins tested. A significant difference was found between dogs reacting to beef versus cows' milk and between dogs reacting to soy versus wheat; thus, the hypothesis of cross-reactivity to ingredients derived from a single animal source or to different plant products was not supported. Similar differences between chicken meat and eggs were not identified. Long-term management of dogs with food allergies is facilitated by identification of the most commonly encountered food allergens. Because cross-reactivity cannot be verified, each protein source should be included separately in food-provocation trials.

Comparison of capnovolumetry-derived dead space parameters with pulmonary function test in normal adults using histamine provocation.

PubMed

Sun, Xiaoli; Zhang, Yan; Yang, Wenlan; Liu, Jinming

2015-04-01

This study in healthy adults was conducted to explore the clinical application of capnovolumetric indices as compared to lung function parameters using histamine provocation. Forty healthy subjects received aerosol histamine or salbutamol in an automatic stimulation system with escalating doses of histamine. Dead space volumes of capnovolumetry and lung function parameters were examined with increased concentrations of histamine at a fixed time interval. The doses of histamine were selected from 0.0562 mg-2.2 mg and 0.1 mg salbutamol was inhaled when a maximal dose of histamine was reached. Baseline values in each group were calculated prior to histamine inhalation. Fowler dead space (VDF), Wolff dead space (VDW), threshold dead space (VDT), Bohr dead space (VDB), forced expiratory volume in 1 s (FEV1 ) and peak expiratory flow (PEF) showed a dose-dependent reduction following histamine provocation, but there were no statistical differences in the measurements at baseline and post S6 provocation. The value of dC3/DV at the maximal dose was significantly increased over its baseline value (P < 0.05). VDF, VDT and VDW were significantly increased after bronchodilator use (P < 0.05 or <0.01). The changes in capnovolumetry did not correspond with the results of lung function test. The dC3/DV and airway dead spaces of capnovolumetry in healthy adults are significantly increased compared to lung function parameters before or after bronchodilator use, suggesting that capnovolumetry is feasible in diagnostic evaluation of airway reactivity, especially for persons who are unable to undertake lung function test. © 2014 John Wiley & Sons Ltd.

A Laboratory Exercise to Illustrate Increased Salivary Cortisol in Response to Three Stressful Conditions Using Competitive ELISA

ERIC Educational Resources Information Center

Haussmann, Mark F.; Vleck, Carol M; Farrar, Eugenia S.

2007-01-01

Perceived stress activates the hypothalamus-pituitary-adrenal axis, resulting in the release of glucocorticoids into the systemic circulation. Glucocorticoids cause the elevation of blood glucose, providing the necessary energy for the organism to cope with stress. Here, we outline a laboratory exercise that uses a competitive ELISA kit to…

Influence of body mass index on the growth hormone response to provocative testing in short children without growth hormone deficiency.

PubMed

Lee, Jieun; Yoon, Juyoung; Kang, Min Jae; Lee, Young Ah; Lee, Seong Yong; Shin, Choong Ho; Yang, Sei Won

2013-09-01

Obesity and its related factors are known to suppress the secretion of growth hormone (GH). We aimed to evaluate the influence of body mass index (BMI) on the peak GH response to provocative testing in short children without GH deficiency. We conducted a retrospective review of medical records of 88 children (2-15 yr old) whose height was less than 3 percentile for one's age and sex, with normal results (peak GH level > 10 ng/mL) of GH provocative testing with clonidine and dopamine. Peak stimulated GH level, height, weight, pubertal status and serum IGF-1 level were measured. Univariate analysis showed that the BMI standard deviation score (SDS) correlated negatively with the natural log (ln) of the peak stimulated GH level (ln peak GH). BMI SDS did not correlate significantly with sex, age, pubertal status, or ln IGF-1 level. BMI SDS correlated negatively with ln peak GH level induced by clonidine but not by dopamine. In stepwise multivariate regression analysis, BMI SDS was the only significant predictor of ln peak GH level in the combination of tests and the clonidine test, but not in the dopamine test. In children without GH deficiency, BMI SDS correlates negatively with the peak GH level. BMI SDS should be included in the analysis of the results of GH provocation tests, especially tests with clonidine.

Optimism as a predictor of the effects of laboratory-induced stress on fears and hope.

PubMed

Kimhi, Shaul; Eshel, Yohanan; Shahar, Eldad

2013-01-01

The objective of the current study is to explore optimism as a predictor of personal and collective fear, as well as hope, following laboratory-induced stress. Students (N = 107; 74 female, 33 male) were assigned randomly to either the experimental (stress--political violence video clip) or the control group (no-stress--nature video clip). Questionnaires of fear and hope were administered immediately after the experiment (Time 1) and 3 weeks later (Time 2). Structural equation modeling indicated the following: (a) Optimism significantly predicted both fear and hope in the stress group at Time 1, but not in the no-stress group. (b) Optimism predicted hope but not fear at Time 2 in the stress group. (c) Hope at Time 1 significantly predicted hope at Time 2, in both the stress and the no-stress groups. (d) Gender did not predict significantly fear at Time 1 in the stress group, despite a significant difference between genders. This study supports previous studies indicating that optimism plays an important role in people's coping with stress. However, based on our research the data raise the question of whether optimism, by itself, or environmental stress, by itself, may accurately predict stress response.

Provocation of left ventricular outflow tract obstruction using nitrate inhalation in hypertrophic cardiomyopathy: Relation to electromechanical delay.

PubMed

Badran, Hala Mahfouz; Ibrahim, Waleed Abdou; Faheem, Naglaa; Yassin, Rehab; Alashkar, Tamer; Yacoub, Magdi

2015-01-01

Left ventricular outflow tract obstruction (LVOT) is an independent predictor of adverse outcome in hypertrophic cardiomyopathy (HCM). It is of major importance that the provocation modalities used are validated against each other. To define the magnitude of LVOT gradients provocation during both isosorbide dinitrate (ISDN) inhalation and treadmill exercise in non-obstructive HCM and analyze the correlation to the electromechanical delay using speckle tracking. We studied 39 HCM pts (64% males, mean age 38 ± 13 years) regional LV longitudinal strain and electromechanical delay (TTP) was analyzed at rest using speckle tracking. LVOT gradient was measured at rest and after ISDN then patients underwent a treadmill exercise echocardiography (EE) and LVOT gradient was measured at peak exercise. The maximum effect of ISDN on LVOT gradient was obtained at 5 minutes, it increased to a significant level in 12 (31%) patients, and in 14 (36%) patients using EE, with 85.6% sensitivity & 100% specificity. Patients with latent obstruction had larger left atrial volume and lower E/A ratio compared to the non-obstructive group (p < 0.01). LVOTG using ISDN was significantly correlated with that using EE (p < 0.0001), resting LVOTG (p < 0.0001), SAM (p < 0.0001), EF% (p < 0.02) and regional electromechanical delay but not related to global LV longitudinal strain. Using multivariate regression, resting LVOTG (p = 0.006) & TTP mid septum (p = 0.01) were found to be independent predictors of latent LVOT obstruction using ISDN. There is a comparable diagnostic value of nitrate inhalation to exercise testing in provocation of LVOT obstruction in HCM. Latent obstruction is predominantly dependent on regional electromechanical delay.

Provocation of left ventricular outflow tract obstruction using nitrate inhalation in hypertrophic cardiomyopathy: Relation to electromechanical delay

PubMed Central

Badran, Hala Mahfouz; Ibrahim, Waleed Abdou; Faheem, Naglaa; Yassin, Rehab; Alashkar, Tamer; Yacoub, Magdi

2015-01-01

Background: Left ventricular outflow tract obstruction (LVOT) is an independent predictor of adverse outcome in hypertrophic cardiomyopathy (HCM). It is of major importance that the provocation modalities used are validated against each other. Aim: To define the magnitude of LVOT gradients provocation during both isosorbide dinitrate (ISDN) inhalation and treadmill exercise in non-obstructive HCM and analyze the correlation to the electromechanical delay using speckle tracking. Methods: We studied 39 HCM pts (64% males, mean age 38 ± 13 years) regional LV longitudinal strain and electromechanical delay (TTP) was analyzed at rest using speckle tracking. LVOT gradient was measured at rest and after ISDN then patients underwent a treadmill exercise echocardiography (EE) and LVOT gradient was measured at peak exercise. Results: The maximum effect of ISDN on LVOT gradient was obtained at 5 minutes, it increased to a significant level in 12 (31%) patients, and in 14 (36%) patients using EE, with 85.6% sensitivity & 100% specificity. Patients with latent obstruction had larger left atrial volume and lower E/A ratio compared to the non-obstructive group (p < 0.01). LVOTG using ISDN was significantly correlated with that using EE (p < 0.0001), resting LVOTG (p < 0.0001), SAM (p < 0.0001), EF% (p < 0.02) and regional electromechanical delay but not related to global LV longitudinal strain. Using multivariate regression, resting LVOTG (p = 0.006) & TTP mid septum (p = 0.01) were found to be independent predictors of latent LVOT obstruction using ISDN. Conclusion: There is a comparable diagnostic value of nitrate inhalation to exercise testing in provocation of LVOT obstruction in HCM. Latent obstruction is predominantly dependent on regional electromechanical delay. PMID:26779503

A systematic review of the diagnostic accuracy of provocative tests of the neck for diagnosing cervical radiculopathy

PubMed Central

Pool, Jan J. M.; van Tulder, Maurits W.; Riphagen, Ingrid I.; de Vet, Henrica C. W.

2006-01-01

Clinical provocative tests of the neck, which position the neck and arm inorder to aggravate or relieve arm symptoms, are commonly used in clinical practice in patients with a suspected cervical radiculopathy. Their diagnostic accuracy, however, has never been examined in a systematic review. A comprehensive search was conducted in order to identify all possible studies fulfilling the inclusion criteria. A study was included if: (1) any provocative test of the neck for diagnosing cervical radiculopathy was identified; (2) any reference standard was used; (3) sensitivity and specificity were reported or could be (re-)calculated; and, (4) the publication was a full report. Two reviewers independently selected studies, and assessed methodological quality. Only six studies met the inclusion criteria, which evaluated five provocative tests. In general, Spurling’s test demonstrated low to moderate sensitivity and high specificity, as did traction/neck distraction, and Valsalva’s maneuver. The upper limb tension test (ULTT) demonstrated high sensitivity and low specificity, while the shoulder abduction test demonstrated low to moderate sensitivity and moderate to high specificity. Common methodological flaws included lack of an optimal reference standard, disease progression bias, spectrum bias, and review bias. Limitations include few primary studies, substantial heterogeneity, and numerous methodological flaws among the studies; therefore, a meta-analysis was not conducted. This review suggests that, when consistent with the history and other physical findings, a positive Spurling’s, traction/neck distraction, and Valsalva’s might be indicative of a cervical radiculopathy, while a negative ULTT might be used to rule it out. However, the lack of evidence precludes any firm conclusions regarding their diagnostic value, especially when used in primary care. More high quality studies are necessary in order to resolve this issue. PMID:17013656

Manifestation of J wave induced by acetylcholine applied for a coronary spasm provocation test in a patient with aborted sudden cardiac death.

PubMed

Kodama, Hiroyuki; Fujita, Kazumasa; Moriyama, Shouhei; Irie, Kei; Noda, Hirotaka; Yokoyama, Taku; Fukata, Mitsuhiro; Arita, Takeshi; Odashiro, Keita; Maruyama, Toru; Akashi, Koichi

2017-06-01

A 51-year-old man with a resuscitation episode was referred to our hospital. Coronary angiography revealed a focal spasm overlapped with organic stenosis where a bare metal stent was implanted. Acetylcholine (ACh) provocation test did not induce chest pain. It revealed no discernible ST-T changes but unmasked a J wave at the end of the QRS complex, which was associated with short-coupled repetitive premature ventricular beats. A J wave reportedly appears immediately before the onset of ventricular fibrillation caused by vasospastic angina. However, a J wave observed newly after a coronary spasm provocation test using ACh without ST-T changes is informative when considering the mechanisms of the J wave.

Physical Examination of the Wrist: Useful Provocative Maneuvers.

PubMed

Kleinman, William B

2015-07-01

Chronic wrist pain resulting from partial interosseous ligament injury remains a diagnostic dilemma for many hand and orthopedic surgeons. Overuse of costly diagnostic studies including magnetic resonance imaging, computed tomography scans, and bone scans can be further frustrating to the clinician because of their inconsistent specificity and reliability in these cases. Physical diagnosis is an effective (and underused) means of establishing a working diagnosis of partial ligament injury to the wrist. Carefully performed provocative maneuvers can be used by the clinician to reproduce the precise character of a patient's problem, reliably establish a working diagnosis, and initiate a plan of treatment. Using precise physical examination techniques, the examiner introduces energy into the wrist in a manner that puts load on specific support ligaments of the carpus, leading to an accurate diagnosis. This article provides a broad spectrum of physical diagnostic tools to help the surgeon develop a working diagnosis of partial wrist ligament injuries in the face of chronic wrist pain and normal x-rays. Copyright © 2015 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Gender differences and the relationships of perceived background stress and psychological distress with cardiovascular responses to laboratory stressors.

PubMed

Allen, Michael T; Bocek, Christine M; Burch, Ashley E

2011-09-01

The primary aim of this study was to evaluate the relationships of perceived background stress and self-reported psychological distress on cardiovascular reactivity during acute laboratory stressors. The Perceived Stress Scale (PSS) was used as the measure of perceived background stress, and the General Health Questionnaire (GHQ) was used as the measure of psychological distress. A secondary aim was to examine whether background stress and psychological distress affected the susceptibility to induction of a negative mood using music. Heart rate (HR) and blood pressure (BP) were measured in 149 female and male college students at rest and during a stressful mental arithmetic (MA) task and a mood induction procedure. Higher scores on the GHQ were associated with lower systolic BP reactivity during the MA task by all participants. Higher scores on the PSS and GHQ were also associated with lower diastolic BP and HR reactivity, but only in females. Thus, higher self-reports of background stress and psychological distress tended to result in blunted reactivity to an acute laboratory challenge. Higher levels of background stress and psychological distress were not associated with greater susceptibility to a negative mood induction. This study adds to the growing literature indicating that potentially negative health outcomes may be associated with diminished cardiovascular reactivity under certain conditions. Copyright © 2011 Elsevier B.V. All rights reserved.

Immediate hypersensitivity to iodinated contrast media: diagnostic accuracy of skin tests and intravenous provocation test with low dose.

PubMed

Sesé, L; Gaouar, H; Autegarden, J-E; Alari, A; Amsler, E; Vial-Dupuy, A; Pecquet, C; Francès, C; Soria, A

2016-03-01

The diagnosis of HSR to iodinated contrast media (ICM) is challenging based on clinical history and skin tests. This study evaluates the negative predictive value (NPV) of skin tests and intravenous provocation test (IPT) with low-dose ICM in patients with suspected immediate hypersensitivity reaction (HSR) to ICM. Thirty-seven patients with suspected immediate hypersensitivity reaction to ICM were included retrospectively. Skin tests and a single-blind placebo-controlled intravenous provocation test (IPT) with low-dose iodinated contrast media (ICM) were performed. Skin tests with ICM were positive in five cases (one skin prick test and five intradermal test). Thirty-six patients were challenged successfully by IPT, and only one patient had a positive challenge result, with a grade I reaction by the Ring and Messmer classification. Ten of 23 patients followed up by telephone were re-exposed to a negative tested ICM during radiologic examination; two experienced a grade I immediate reaction. For immediate hypersensitivity reaction to ICM, the NPV for skin tests and IPT with low dose was 80% (95% CI 44-97%). © 2016 John Wiley & Sons Ltd.

Effect of Stress and Saturation on Shear Wave Anisotropy: Laboratory Observations Using Laser Doppler Interferometry

NASA Astrophysics Data System (ADS)

Lebedev, M.; Collet, O.; Bona, A.; Gurevich, B.

2015-12-01

Estimations of hydrocarbon and water resources as well as reservoir management during production are the main challenges facing the resource recovery industry nowadays. The recently discovered reservoirs are not only deep but they are also located in complicated geological formations. Hence, the effect of anisotropy on reservoir imaging becomes significant. Shear wave (S-wave) splitting has been observed in the field and laboratory experiments for decades. Despite the fact that S-wave splitting is widely used for evaluation of subsurface anisotropy, the effects of stresses as well fluid saturation on anisotropy have not been understood in detail. In this paper we present the laboratory study of the effect of stress and saturation on S-wave splitting for a Bentheim sandstone sample. The cubic sample (50mm3), porosity 22%, density 1890kg/m3) was placed into a true-triaxial cell. The sample was subjected to several combinations of stresses varying from 0 to 10MPa and applied to the sample in two directions (X and Y), while no stress was applied to the sample in the Z-direction. The sample's bedding was nearly oriented parallel to Y-Z plane. The ultrasonic S-waves were exited at a frequency of 0.5MHz by a piezoelectric transducer and were propagating in the Z-direction. Upon wave arrival onto the free surface the displacement of the surface was monitored by a Laser Doppler interferometer. Hodograms of the central point of the dry sample (Fig. 1) demonstrate how S-wave polarizations for both "fast" and "slow" S-waves change when increasing the stress in the X direction, while the stress in direction Y is kept constant at 3 MPa. Polarization of the fast S wave is shifted towards the X-axis (axis of the maximum stress). While both S-wave velocities increase with stress, the anisotropy level remains the same. No shift of polarization of fast wave was observed when the stress along the Y-axis was kept at 3 MPa, while the stress along the X-axis was increasing. However, in

Examination of patients for carpal tunnel syndrome sensibility, provocative, and motor testing.

PubMed

Palumbo, Carl F; Szabo, Robert M

2002-05-01

The value of a test for carpal tunnel syndrome (CTS) depends on the purpose of performing the test. When screening a large population with a low prevalence for CTS, a test with a high sensitivity is needed so that no possible case goes undetected. However, in order to establish a diagnosis, a more specific test is required. Using a combination of physical examination techniques, including sensibility and provocative testing, the probability of correctly diagnosing CTS without relying on electrodiagnostic studies can be very high. Because CTS is a clinical syndrome, the diagnosis should be made on clinical grounds. Electrodiagnosis is extremely important, however, in its ability to objectively document median nerve slowing and eliminate other competing differential diagnoses.

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

PubMed

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

2018-05-01

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

Stress, deformation and micromorphological aspects of soil freezing under laboratory conditions

NASA Astrophysics Data System (ADS)

Jetchick, Elizabeth

In this thesis, frost heave is viewed as a process resulting from the interactions between thermodynamic conditions, soil environment controls such as texture, stress/deformation conditions and soil microstructure. A series of laboratory experiments was devised to investigate the links between these aspects. Because a limited number of studies exist on the development of internal stresses and strains in freezing soil, the work focussed on obtaining rheological data using conventional soil strain gauges and prototype stress transducers. A fine-grained unstructured silt was placed in a column (30 cm diameter by 100 cm length) and subjected to freezing and freeze-thaw cycles from the top down, lasting up to three months. Heat and water flows, as well as stresses and strains were monitored. The frozen soil was sectioned at the end of four of the experiments to examine the soil fabrics that had developed. From the experimental results, schematic stress and strain curves are proposed. For a single freeze cycle, compressive normal and tensile normal stresses were recorded simultaneously by the measuring devices within the freezing soil profile. Ice lens inception took place when the stress field changed, a condition which occurred either at the frost front level or at the base of the growing ice lens. Negative and positive strains reflected the different stress states that were sustained below and above the freezing front. Negative strains or soil consolidation took place as stresses increased before the passage of the frost line. Negligible soil strains were recorded as maximum soil consolidation was attained, before soil expansion. Distinct positive strain patterns indicating secondary and continuing heave, were recorded simultaneously throughout a thickness of soil, over a range of temperatures. Ice lens growth mostly took place as secondary frost heave, but continuing heave was measured, and the temperature conditions for both types of heave were determined. During

Maternal risk factors in fetal alcohol syndrome: provocative and permissive influences.

PubMed

Abel, E L; Hannigan, J H

1995-01-01

We present an hypothesis integrating epidemiological, clinical case, and basic biomedical research to explain why only relatively few women who drink alcohol during pregnancy give birth to children with alcohol-related birth defects (ARBDs), in particular, Fetal Alcohol Syndrome (FAS). We argue that specific sociobehavioral risk factors, e.g., low socioeconomic status, are permissive for FAS in that they provide the context for increased vulnerability. We illustrate how these permissive factors are related to biological factors, e.g., decreased antioxidant status, which in conjunction with alcohol, provoke FAS/ARBDs in vulnerable fetuses. We propose an integrative heuristic model hypothesizing that these permissive and provocative factors increase the likelihood of FAS/ARBDs because they potentiate two related mechanisms of alcohol-induced teratogenesis, specifically, maternal/fetal hypoxia and free radical formation.

The Relation between Early Adolescents' Trust Beliefs in Peers and Reactions to Peer Provocation: Attributions of Intention and Retaliation

ERIC Educational Resources Information Center

Rotenberg, Ken J.; Betts, Lucy R.; Moore, Jolene

2013-01-01

The authors examined the relation between early adolescents' trust beliefs in peers and both their attributions for, and retaliatory aggression to, peer provocation. One hundred and eight-five early adolescents (102 male) from the United Kingdom (M age = 12 years, 2 months, SD = 3 months) completed the Children's Generalized Trust Beliefs in peer…

Provocative discography screening improves surgical outcome.

PubMed

Margetic, Petra; Pavic, Roman; Stancic, Marin F

2013-10-01

The objective of this study was to compare the surgical outcomes of patients operated on, with or without discography prior to operation. The study was designed as a randomized controlled trial, using power analysis with McNemar's test on two correlated proportions. The study comprised of 310 patients divided into trial (207) and control (103) groups. Inclusion criteria were low back pain resistant to nonsurgical treatment for more than 6 months and conventional radiological findings showing degenerative changes without a clear generator of pain. Exclusion criteria were red flags (tumor, trauma, and infection). After standard radiological diagnostic imaging (X-ray, CT, and MR), patients filled in the Oswestry Disability Index (ODI), SF-36, Zung, and MSP questionnaires. Depending on their radiological findings, patients were included and randomly placed in the trial or control group. At the 1-year follow-up examination, patients filled in the ODI, SF-36, and Likert scale questionnaires. The difference between preoperative and postoperative ODI in the control group degenerative disc disease (DDD) subgroup was 22.07 %. The difference between preoperative and postoperative ODI in the trial group DDD subgroup was 35.04 %. Differences between preoperative and postoperative ODI in the control group other indications subgroup was 26.13 %. Differences between preoperative and postoperative ODI in the trial group other indications subgroup was 28.42 %. DDD treated surgically without discography did not reach the clinically significant improvement of 15 ODI points for the patients treated with fusion. Provocative discography screening with psychological testing in the trial group made improvement following fusion clinically significant.

Food hypersensitivity reactions in Soft Coated Wheaten Terriers with protein-losing enteropathy or protein-losing nephropathy or both: gastroscopic food sensitivity testing, dietary provocation, and fecal immunoglobulin E.

PubMed

Vaden, S L; Hammerberg, B; Davenport, D J; Orton, S M; Trogdon, M M; Melgarejo, L T; VanCamp, S D; Williams, D A

2000-01-01

The purpose of this study was to evaluate Soft Coated Wheaten Terriers (SCWTs) affected with protein-losing enteropathy (PLE) or protein-losing nephropathy (PLN) or both for allergy to food. We performed gastroscopic food-sensitivity testing, a provocative dietary trial, and measurement of fecal immunoglobulin E (IgE) in 6 SCWTs affected with PLE or PLN or both. Positive gastroscopic food-sensitivity test reactions were noted in 5 of 6 dogs. Positive reactions were found to milk in 4 dogs, to lamb in 2 dogs, and to wheat and chicken each in 1 dog. Adverse reactions to food (diarrhea, vomiting, or pruritus) were detected in all 6 dogs during the provocative dietary trial. Adverse reactions were found to corn in 5 dogs, to tofu in 3 dogs, to cottage cheese in 2 dogs, to milk in 2 dogs, to farina cream of wheat in 2 dogs, and to lamb in 2 dogs. Serum albumin concentrations significantly decreased and fecal alpha1-protease inhibitor concentration significantly increased 4 days after the provocative trial when compared with baseline values. Antigen-specific fecal IgE varied throughout the provocative trial, with peak levels following ingestion of test meals. We conclude that food hypersensitivities are present in SCWTs affected with the syndrome of PLE/PLN. Mild inflammatory bowel disease was already established in the 6 SCWTs of this report at the time of study, making it impossible to determine if food allergies were the cause or result of the enteric disease.

Laboratory observations of fault strength in response to changes in normal stress

USGS Publications Warehouse

Kilgore, Brian D.; Lozos, Julian; Beeler, Nicholas M.; Oglesby, David

2012-01-01

Changes in fault normal stress can either inhibit or promote rupture propagation, depending on the fault geometry and on how fault shear strength varies in response to the normal stress change. A better understanding of this dependence will lead to improved earthquake simulation techniques, and ultimately, improved earthquake hazard mitigation efforts. We present the results of new laboratory experiments investigating the effects of step changes in fault normal stress on the fault shear strength during sliding, using bare Westerly granite samples, with roughened sliding surfaces, in a double direct shear apparatus. Previous experimental studies examining the shear strength following a step change in the normal stress produce contradictory results: a set of double direct shear experiments indicates that the shear strength of a fault responds immediately, and then is followed by a prolonged slip-dependent response, while a set of shock loading experiments indicates that there is no immediate component, and the response is purely gradual and slip-dependent. In our new, high-resolution experiments, we observe that the acoustic transmissivity and dilatancy of simulated faults in our tests respond immediately to changes in the normal stress, consistent with the interpretations of previous investigations, and verify an immediate increase in the area of contact between the roughened sliding surfaces as normal stress increases. However, the shear strength of the fault does not immediately increase, indicating that the new area of contact between the rough fault surfaces does not appear preloaded with any shear resistance or strength. Additional slip is required for the fault to achieve a new shear strength appropriate for its new loading conditions, consistent with previous observations made during shock loading.

Provocative Endoscopy to Identify Bleeding Site in Upper Gastrointestinal Bleeding: A Novel Approach in Transarterial Embolization.

PubMed

Kamo, Minobu; Fuwa, Sokun; Fukuda, Katsuyuki; Fujita, Yoshiyuki; Kurihara, Yasuyuki

2016-07-01

This report describes a novel approach to endoscopically induce bleeding by removing a clot from the bleeding site during angiography for upper gastrointestinal (UGI) hemorrhage. This procedure enabled accurate identification of the bleeding site, allowing for successful targeted embolization despite a negative initial angiogram. Provocative endoscopy may be a feasible and useful option for angiography of obscure bleeding sites in patients with UGI arterial hemorrhage. Copyright © 2016 SIR. Published by Elsevier Inc. All rights reserved.

Examining Infants' Cortisol Responses to Laboratory Tasks among Children Varying in Attachment Disorganization: Stress Reactivity or Return to Baseline?

ERIC Educational Resources Information Center

Bernard, Kristin; Dozier, Mary

2010-01-01

Cortisol is a hormone involved in mounting a stress response in humans. The evidence of stress reactivity among young children has been mixed, however. In the present study, the order of two laboratory tasks (i.e., Strange Situation and play) was counterbalanced, and home saliva samples were obtained. Saliva samples were also collected upon the…

Cold-provocation testing for the vascular component of hand-arm vibration syndrome in health surveillance.

PubMed

Poole, Kerry; Elms, Joanne; Mason, Howard

2006-10-01

The aim was to investigate whether the use of infra-red thermography (I-R) and measurement of temperature gradients along the finger could improve the diagnostic accuracy of cold-provocation testing (15 degrees C for 5 min) in vascular hand-arm vibration syndrome (HAVS). Twenty-one controls and 33 individuals with stages 2/3V HAVS were studied. The standard measurement of time to rewarm by 4 degrees C (T4 degrees C) and temperature gradients between the finger tip, base and middle (measured using I-R) were calculated. Receiver Operating Characteristics (ROC) analysis to distinguish between the two groups revealed that for T4 degrees C the area under the ROC curve was not statistically significantly different from 0.5 (0.64 95% confidence interval 0.49-0.76). The difference between the tip and middle portion of the finger during the sixth minute of recovery was the most promising gradient with an area of 0.76 (95% confidence interval 0.62-0.87), and sensitivity and specificity of 57.6% and 85.7% respectively. However, this was not significantly different from that for the time to rewarm by 4 degrees C. In conclusion, the cold-provocation test used in this study does not appear to discriminate between individuals with stage 2/3V HAVS and controls and this is not improved by the measurement of temperature gradients along the fingers using I-R.

Avoidant Responses to Interpersonal Provocation Are Associated with Increased Amygdala and Decreased Mentalizing Network Activity

PubMed Central

Krämer, Ulrike M.

2017-01-01

When intentionally pushed or insulted, one can either flee from the provoker or retaliate. The implementation of such fight-or-flight decisions is a central aspect in the genesis and evolution of aggression episodes, yet it is usually investigated only indirectly or in nonsocial situations. In the present fMRI study, we aimed to distinguish brain regions associated with aggressive and avoidant responses to interpersonal provocation in humans. Participants (thirty-six healthy young women) could either avoid or face a highly (HP) and a lowly (LP) provoking opponent in a competitive reaction time task: the fight-or-escape (FOE) paradigm. Subjects avoided the HP more often, but retaliated when facing her. Moreover, they chose to fight the HP more quickly, and showed increased heart rate (HR) right before confronting her. Orbitofrontal cortex (OFC) and sensorimotor cortex were more active when participants decided to fight, whereas the mentalizing network was engaged when deciding to avoid. Importantly, avoiding the HP relative to the LP was associated with both higher activation in the right basolateral amygdala and lower relative activity in several mentalizing regions [e.g., medial and inferior frontal gyrus (IFG), temporal-parietal junction (TPJ)]. These results suggest that avoidant responses to provocation might result from heightened threat anticipation and are associated with reduced perspective taking. Furthermore, our study helps to reconcile conflicting findings on the role of the mentalizing network, the amygdala, and the OFC in aggression. PMID:28660251

Introduction to provocative questions in left-right asymmetry.

PubMed

Levin, Michael; Klar, Amar J S; Ramsdell, Ann F

2016-12-19

Left-right asymmetry is a phenomenon that has a broad appeal-to anatomists, developmental biologists and evolutionary biologists-because it is a morphological feature of organisms that spans scales of size and levels of organization, from unicellular protists, to vertebrate organs, to social behaviour. Here, we highlight a number of important aspects of asymmetry that encompass several areas of biology-cell-level, physiological, genetic, anatomical and evolutionary components-and that are based on research conducted in diverse model systems, ranging from single cells to invertebrates to human developmental disorders. Together, the contributions in this issue reveal a heretofore-unsuspected variety in asymmetry mechanisms, including ancient chirality elements that could underlie a much more universal basis to asymmetry development, and provide much fodder for thought with far reaching implications in biomedical, developmental, evolutionary and synthetic biology. The new emerging theme of binary cell-fate choice, promoted by asymmetric cell division of a deterministic cell, has focused on investigating asymmetry mechanisms functioning at the single cell level. These include cytoskeleton and DNA chain asymmetry-mechanisms that are amplified and coordinated with those employed for the determination of the anterior-posterior and dorsal-ventral axes of the embryo.This article is part of the themed issue 'Provocative questions in left-right asymmetry'. © 2016 The Author(s).

Anticipatory stress associated with functional magnetic resonance imaging: Implications for psychosocial stress research.

PubMed

Gossett, Ethan W; Wheelock, Muriah D; Goodman, Adam M; Orem, Tyler R; Harnett, Nathaniel G; Wood, Kimberly H; Mrug, Sylvie; Granger, Douglas A; Knight, David C

2018-03-01

Stress tasks performed during functional magnetic resonance imaging (fMRI) elicit a relatively small cortisol response compared to stress tasks completed in a traditional behavioral laboratory, which may be due to apprehension of fMRI that elicits an anticipatory stress response. The present study investigated whether anticipatory stress is greater prior to research completed in an MRI environment than in a traditional behavioral laboratory. Anticipatory stress (indexed by cortisol) was greater prior to testing in the MRI environment than traditional behavioral laboratory. Furthermore, anticipation of fMRI elicited a cortisol response commensurate with the response to the stress task in the behavioral laboratory. However, in the MRI environment, post-stress cortisol was significantly lower than baseline cortisol. Taken together, these findings suggest the stress elicited by anticipation of fMRI may lead to acute elevations in cortisol prior to scanning, which may in turn disrupt the cortisol response to stress tasks performed during scanning. Copyright © 2018 Elsevier B.V. All rights reserved.

Difference Between Dormant Conduction Sites Revealed by Adenosine Triphosphate Provocation and Unipolar Pace-Capture Sites Along the Ablation Line After Pulmonary Vein Isolation.

PubMed

Kogawa, Rikitake; Okumura, Yasuo; Watanabe, Ichiro; Sonoda, Kazumasa; Sasaki, Naoko; Takahashi, Keiko; Iso, Kazuki; Nagashima, Koichi; Ohkubo, Kimie; Nakai, Toshiko; Kunimoto, Satoshi; Hirayama, Atsushi

2016-01-01

Dormant pulmonary vein (PV) conduction revealed by adenosine/adenosine triphosphate (ATP) provocation test and exit block to the left atrium by pacing from the PV side of the ablation line ("pace and ablate" method) are used to ensure durable pulmonary vein isolation (PVI). However, the mechanistic relation between ATP-provoked PV reconnection and the unexcitable gap along the ablation line is unclear.Forty-five patients with atrial fibrillation (AF) (paroxysmal: 31 patients, persistent: 14 patients; age: 61.1 ± 9.7 years) underwent extensive encircling PVI (EEPVI, 179 PVs). After completion of EEPVI, an ATP provocation test (30 mg, bolus injection) and unipolar pacing (output, 10 mA; pulse width, 2 ms) were performed along the previous EEPVI ablation line to identify excitable gaps. Dormant conduction was revealed in 29 (34 sites) of 179 PVs (16.2%) after EEP-VI (22/45 patients). Pace capture was revealed in 59 (89 sites) of 179 PVs (33.0%) after EEPVI (39/45 patients), and overlapping sites, ie, sites showing both dormant conduction and pace capture, were observed in 22 of 179 (12.3%) PVs (17/45 patients).Some of the ATP-provoked dormant PV reconnection sites were identical to the sites with excitable gaps revealed by pace capture, but most of the PV sites were differently distributed, suggesting that the main underling mechanism differs between these two forms of reconnection. These findings also suggest that performance of the ATP provocation test followed by the "pace and ablate" method can reduce the occurrence of chronic PV reconnections.

Interrelations of Justice, Rejection, Provocation, and Moral Disgust Sensitivity and Their Links with the Hostile Attribution Bias, Trait Anger, and Aggression

PubMed Central

Bondü, Rebecca; Richter, Philipp

2016-01-01

Several personality dispositions with common features capturing sensitivities to negative social cues have recently been introduced into psychological research. To date, however, little is known about their interrelations, their conjoint effects on behavior, or their interplay with other risk factors. We asked N = 349 adults from Germany to rate their justice, rejection, moral disgust, and provocation sensitivity, hostile attribution bias, trait anger, and forms and functions of aggression. The sensitivity measures were mostly positively correlated; particularly those with an egoistic focus, such as victim justice, rejection, and provocation sensitivity, hostile attributions and trait anger as well as those with an altruistic focus, such as observer justice, perpetrator justice, and moral disgust sensitivity. The sensitivity measures had independent and differential effects on forms and functions of aggression when considered simultaneously and when controlling for hostile attributions and anger. They could not be integrated into a single factor of interpersonal sensitivity or reduced to other well-known risk factors for aggression. The sensitivity measures, therefore, require consideration in predicting and preventing aggression. PMID:27303351

Allergic Asthmatics Show Divergent Lipid Mediator Profiles from Healthy Controls Both at Baseline and following Birch Pollen Provocation

PubMed Central

Lundström, Susanna L.; Yang, Jun; Källberg, Henrik J.; Thunberg, Sarah; Gafvelin, Guro; Haeggström, Jesper Z.; Grönneberg, Reidar; Grunewald, Johan; van Hage, Marianne; Hammock, Bruce D.; Eklund, Anders; Wheelock, Åsa M.; Wheelock, Craig E.

2012-01-01

Background Asthma is a respiratory tract disorder characterized by airway hyper-reactivity and chronic inflammation. Allergic asthma is associated with the production of allergen-specific IgE and expansion of allergen-specific T-cell populations. Progression of allergic inflammation is driven by T-helper type 2 (Th2) mediators and is associated with alterations in the levels of lipid mediators. Objectives Responses of the respiratory system to birch allergen provocation in allergic asthmatics were investigated. Eicosanoids and other oxylipins were quantified in the bronchoalveolar lumen to provide a measure of shifts in lipid mediators associated with allergen challenge in allergic asthmatics. Methods Eighty-seven lipid mediators representing the cyclooxygenase (COX), lipoxygenase (LOX) and cytochrome P450 (CYP) metabolic pathways were screened via LC-MS/MS following off-line extraction of bronchoalveolar lavage fluid (BALF). Multivariate statistics using OPLS were employed to interrogate acquired oxylipin data in combination with immunological markers. Results Thirty-two oxylipins were quantified, with baseline asthmatics possessing a different oxylipin profile relative to healthy individuals that became more distinct following allergen provocation. The most prominent differences included 15-LOX-derived ω-3 and ω-6 oxylipins. Shared-and-Unique-Structures (SUS)-plot modeling showed a correlation (R2 = 0.7) between OPLS models for baseline asthmatics (R2Y[cum] = 0.87, Q2[cum] = 0.51) and allergen-provoked asthmatics (R2Y[cum] = 0.95, Q2[cum] = 0.73), with the majority of quantified lipid mediators and cytokines contributing equally to both groups. Unique structures for allergen provocation included leukotrienes (LTB4 and 6-trans-LTB4), CYP-derivatives of linoleic acid (epoxides/diols), and IL-10. Conclusions Differences in asthmatic relative to healthy profiles suggest a role for 15-LOX products of both ω-6 and ω-3 origin in allergic

Individual Differences in Automatic Emotion Regulation Interact with Primed Emotion Regulation during an Anger Provocation.

PubMed

Zhang, Jing; Lipp, Ottmar V; Hu, Ping

2017-01-01

The current study investigated the interactive effects of individual differences in automatic emotion regulation (AER) and primed emotion regulation strategy on skin conductance level (SCL) and heart rate during provoked anger. The study was a 2 × 2 [AER tendency (expression vs. control) × priming (expression vs. control)] between subject design. Participants were assigned to two groups according to their performance on an emotion regulation-IAT (differentiating automatic emotion control tendency and automatic emotion expression tendency). Then participants of the two groups were randomly assigned to two emotion regulation priming conditions (emotion control priming or emotion expression priming). Anger was provoked by blaming participants for slow performance during a subsequent backward subtraction task. In anger provocation, SCL of individuals with automatic emotion control tendencies in the control priming condition was lower than of those with automatic emotion control tendencies in the expression priming condition. However, SCL of individuals with automatic emotion expression tendencies did no differ in the automatic emotion control priming or the automatic emotion expression priming condition. Heart rate during anger provocation was higher in individuals with automatic emotion expression tendencies than in individuals with automatic emotion control tendencies regardless of priming condition. This pattern indicates an interactive effect of individual differences in AER and emotion regulation priming on SCL, which is an index of emotional arousal. Heart rate was only sensitive to the individual differences in AER, and did not reflect this interaction. This finding has implications for clinical studies of the use of emotion regulation strategy training suggesting that different practices are optimal for individuals who differ in AER tendencies.

Triggers of the HSP70 stress response: environmental responses and laboratory manipulation in an Antarctic marine invertebrate (Nacella concinna)

PubMed Central

Peck, Lloyd S.

2009-01-01

The Antarctic limpet, Nacella concinna, exhibits the classical heat shock response, with up-regulation of duplicated forms of the inducible heat shock protein 70 (HSP70) gene in response to experimental manipulation of seawater temperatures. However, this response only occurs in the laboratory at temperatures well in excess of any experienced in the field. Subsequent environmental sampling of inter-tidal animals also showed up-regulation of these genes, but at temperature thresholds much lower than those required to elicit a response in the laboratory. It was hypothesised that this was a reflection of the complexity of the stresses encountered in the inter-tidal region. Here, we describe a further series of experiments comprising both laboratory manipulation and environmental sampling of N. concinna. We investigate the expression of HSP70 gene family members (HSP70A, HSP70B, GRP78 and HSC70) in response to a further suite of environmental stressors: seasonal and experimental cold, freshwater, desiccation, chronic heat and periodic emersion. Lowered temperatures (−1.9°C and −1.6°C), generally produced a down-regulation of all HSP70 family members, with some up-regulation of HSC70 when emerging from the winter period and increasing sea temperatures. There was no significant response to freshwater immersion. In response to acute and chronic heat treatments plus simulated tidal cycles, the data showed a clear pattern. HSP70A showed a strong but very short-term response to heat whilst the duplicated HSP70B also showed heat to be a trigger, but had a more sustained response to complex stresses. GRP78 expression indicates that it was acting as a generalised stress response under the experimental conditions described here. HSC70 was the major chaperone invoked in response to long-term stresses of varying types. These results provide intriguing clues not only to the complexity of HSP70 gene expression in response to environmental change but also insights into the

Triggers of the HSP70 stress response: environmental responses and laboratory manipulation in an Antarctic marine invertebrate (Nacella concinna).

PubMed

Clark, Melody S; Peck, Lloyd S

2009-11-01

The Antarctic limpet, Nacella concinna, exhibits the classical heat shock response, with up-regulation of duplicated forms of the inducible heat shock protein 70 (HSP70) gene in response to experimental manipulation of seawater temperatures. However, this response only occurs in the laboratory at temperatures well in excess of any experienced in the field. Subsequent environmental sampling of inter-tidal animals also showed up-regulation of these genes, but at temperature thresholds much lower than those required to elicit a response in the laboratory. It was hypothesised that this was a reflection of the complexity of the stresses encountered in the inter-tidal region. Here, we describe a further series of experiments comprising both laboratory manipulation and environmental sampling of N. concinna. We investigate the expression of HSP70 gene family members (HSP70A, HSP70B, GRP78 and HSC70) in response to a further suite of environmental stressors: seasonal and experimental cold, freshwater, desiccation, chronic heat and periodic emersion. Lowered temperatures (-1.9 degrees C and -1.6 degrees C), generally produced a down-regulation of all HSP70 family members, with some up-regulation of HSC70 when emerging from the winter period and increasing sea temperatures. There was no significant response to freshwater immersion. In response to acute and chronic heat treatments plus simulated tidal cycles, the data showed a clear pattern. HSP70A showed a strong but very short-term response to heat whilst the duplicated HSP70B also showed heat to be a trigger, but had a more sustained response to complex stresses. GRP78 expression indicates that it was acting as a generalised stress response under the experimental conditions described here. HSC70 was the major chaperone invoked in response to long-term stresses of varying types. These results provide intriguing clues not only to the complexity of HSP70 gene expression in response to environmental change but also insights

The spectral response of Buxus sempervirens to different types of environmental stress - A laboratory experiment

NASA Astrophysics Data System (ADS)

de Jong, Steven M.; Addink, Elisabeth A.; Hoogenboom, Priscilla; Nijland, Wiebe

2012-11-01

The European Mediterranean regions are expected to encounter drier summer conditions and warmer temperatures for the winter of +2 °C and of +5 °C for the summer in the next six decennia. As a result the natural vegetation will face harsher conditions due to lower water availability, longer summer droughts and higher temperatures resulting in plant stress conditions. To monitor vegetation conditions like stress and leaf area index dynamics in our study area in Mediterranean France we use earth observation techniques like imaging spectroscopy. To assist image analysis interpretation we carried out a laboratory experiment to investigate the spectral and visible response of Buxus sempervirens, a common Mediterranean species, to five different types of stress: drought, drought-and-heat, light deprivation, total saturation and chlorine poisoning. For 52 days plants were subjected to stress. We collected data on the visible and spectral signs, and calculated thirteen vegetation indices. The plant's response time to different stress types varied from 10 to 32 days. Spectroscopic techniques revealed plant stress up to 15 days earlier than visual inspection. Visible signs of stress of the plants included curling and shrinking of the leaves, de-colouring of the leaves, leaves becoming breakable, opening up of the plant's canopy and sagging of the branches. Spectral signs of stress occurred first in the water absorption bands at 1450 and 1940 nm, followed by reduced absorption in the visible wavelengths, and next by reduced reflectance in near infrared. Light deprivation did not result in any stress signs, while drought, drought and heat and chlorine poisoning resulted in significant stress. The spectral response did not show differences for different stress types. Analysis of the vegetation indices identified the Carter-2 (R695/R760), the Red-Green Index (R690/R550) and the Vogelman-2 (R734 - R747)/(R715 + R726) as the best performing ones to identify stress. The lab

Muscle Weakness in the Empty and Full Can Tests Cannot Differentiate Rotator Cuff Tear from Cervical Spondylotic Amyotrophy: Pain Provocation is a Useful Finding.

PubMed

Iwata, Eiichiro; Shigematsu, Hideki; Inoue, Kazuya; Egawa, Takuya; Sakamoto, Yoshihiro; Tanaka, Yasuhito

2017-01-01

Rotator cuff tears and cervical spondylotic amyotrophy (CSA) are often confused as the main symptom in those with difficulty in shoulder elevation. Empty and full can tests are frequently used for the clinical diagnosis of rotator cuff tears. The aim of the present study was to investigate whether the empty and full can test results can help differentiate rotator cuff tears from CSA. Twenty-seven consecutive patients with rotator cuff tears and 25 with CSA were enrolled. We prospectively performed empty and full can tests in patients with rotator cuff tears and CSA. The following signs were considered positive: (a) muscle weakness during the empty can test, (b) muscle weakness during the full can test, (c) pain provocation during the empty can test, and (d) pain provocation during the full can test. We calculated the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of rotator cuff tears for each positive finding. The sensitivity and specificity of each index were as follows (sensitivity, specificity, PPV, NPV): (a) 77.8%, 0%, 45.7%, 0%; (b) 66.7%, 4.0%, 42.9%, 10.0%; (c) 88.9%, 96.0%, 96.0%, 88.9%; and (d) 74.1%, 96.0%, 95.2%, 77.4%. There were significant differences for each index. Muscle weakness during the empty and full can tests was not useful in differentiating rotator cuff tears from CSA because of low specificity and PPV. However, pain provocation was useful in differentiating these two conditions because of high specificity and PPV.

Tracking Local Spatiotemporal Microfracturing Processes and Stress Field Evolution Before and After Laboratory Fault Slip

NASA Astrophysics Data System (ADS)

Kwiatek, G.; Orlecka-Sikora, B.; Goebel, T.; Martínez-Garzón, P.; Dresen, G.; Bohnhoff, M.

2017-12-01

In this study we investigate details of spatial and temporal evolution of the stress field and damage at a pre-existing fault plane in laboratory stick-slip friction experiments performed on Westerly Granite sample. Specimen of 10 cm height and 4 cm diameter was deformed at a constant strain rate of 3×10-6 s-1 and confining pressure of 150 MPa. Here we analyze a series of 6 macroscopic slip events occurring on a rough fault during the course of experiment. Each macroscopic slip was associated with an intense femtoseismic acoustic emission (AE) activity recorded using a 16-channel transient recording system. To monitor the the spatiotemporal damage evolution, and unravel the micromechanical processes governing nucleation and propagation of slip events, we analyzed AE source characteristics (magnitude, seismic moment tensors, focal mechanisms), as well as the statistical properties (b-, c-, d- value) of femtoseismicity. In addition, the calculated AE focal mechanisms were used to reveal the spatiotemporal evolution of local stress field orientations and stress shape ratio coefficients over the fault plane, as well as additional parameters quantifying proximity to failure of individual fault patches. The calculated characteristics are used to comprehensively describe the complexity of the spatial and temporal evolution of the stress over the fault plane, and properties of the corresponding seismicity before and after the macroscopic slips. The observed faulting processes and characteristics are discussed in the context of global strain and stress changes, fault maturation, and earthquake stress drop.

Stress responses to repeated exposure to a combined physical and social evaluative laboratory stressor in young healthy males.

PubMed

Boyle, N B; Lawton, C; Arkbåge, K; West, S G; Thorell, L; Hofman, D; Weeks, A; Myrissa, K; Croden, F; Dye, L

2016-01-01

Repeated exposure to homotypic laboratory psychosocial stressors typically instigates rapid habituation in hypothalamic-pituitary-adrenal (HPA) axis-mediated stress responses in humans. However, emerging evidence suggests the combination of physical stress and social evaluative threat may be sufficient to attenuate this response habituation. Neuroendocrine, cardiovascular and subjective stress responses following repeated exposure to a combined physical and social evaluative stress protocol were assessed to examine the habituation response dynamic in this context. The speech task of the Trier social stress test (TSST; Kirschbaum et al., 1993) and the socially evaluated cold pressor task (SECPT; Schwabe et al., 2008) were administered in a combined stressor protocol. Salivary cortisol, cardiovascular and subjective stress responses to a non-stress control and repeat stressor exposure separated by six weeks were examined in males (N=24) in a crossover manner. Stressor exposure resulted in significant elevations in all stress parameters. In contrast to the commonly reported habituation in cortisol response, a comparable post-stress response was demonstrated. Cortisol, heart rate and subjective stress responses were also characterised by a heightened response in anticipation to repeated stress exposure. Blood pressure responses were comparatively uniform across repeated exposures. Findings suggest a combined physical and social evaluative stressor is a potentially useful method for study designs that require repeated presentation of a homotypic stressor. Copyright © 2015 Elsevier Ltd. All rights reserved.

Stressful Presentations: Mild Cold Stress in Laboratory Mice Influences Phenotype of Dendritic Cells in Naïve and Tumor-Bearing Mice

PubMed Central

Kokolus, Kathleen M.; Spangler, Haley M.; Povinelli, Benjamin J.; Farren, Matthew R.; Lee, Kelvin P.; Repasky, Elizabeth A.

2013-01-01

The ability of dendritic cells (DCs) to stimulate and regulate T cells is critical to effective anti-tumor immunity. Therefore, it is important to fully recognize any inherent factors which may influence DC function under experimental conditions, especially in laboratory mice since they are used so heavily to model immune responses. The goals of this report are to 1) briefly summarize previous work revealing how DCs respond to various forms of physiological stress and 2) to present new data highlighting the potential for chronic mild cold stress inherent to mice housed at the required standard ambient temperatures to influence baseline DCs properties in naïve and tumor-bearing mice. As recent data from our group shows that CD8+ T cell function is significantly altered by chronic mild cold stress and since DC function is crucial for CD8+ T cell activation, we wondered whether housing temperature may also be influencing DC function. Here we report that there are several significant phenotypical and functional differences among DC subsets in naïve and tumor-bearing mice housed at either standard housing temperature or at a thermoneutral ambient temperature, which significantly reduces the extent of cold stress. The new data presented here strongly suggests that, by itself, the housing temperature of mice can affect fundamental properties and functions of DCs. Therefore differences in basal levels of stress due to housing should be taken into consideration when interpreting experiments designed to evaluate the impact of additional variables, including other stressors on DC function. PMID:24575090

Stressful presentations: mild cold stress in laboratory mice influences phenotype of dendritic cells in naïve and tumor-bearing mice.

PubMed

Kokolus, Kathleen M; Spangler, Haley M; Povinelli, Benjamin J; Farren, Matthew R; Lee, Kelvin P; Repasky, Elizabeth A

2014-01-01

The ability of dendritic cells (DCs) to stimulate and regulate T cells is critical to effective anti-tumor immunity. Therefore, it is important to fully recognize any inherent factors which may influence DC function under experimental conditions, especially in laboratory mice since they are used so heavily to model immune responses. The goals of this report are to 1) briefly summarize previous work revealing how DCs respond to various forms of physiological stress and 2) to present new data highlighting the potential for chronic mild cold stress inherent to mice housed at the required standard ambient temperatures to influence baseline DCs properties in naïve and tumor-bearing mice. As recent data from our group shows that CD8(+) T cell function is significantly altered by chronic mild cold stress and since DC function is crucial for CD8(+) T cell activation, we wondered whether housing temperature may also be influencing DC function. Here we report that there are several significant phenotypical and functional differences among DC subsets in naïve and tumor-bearing mice housed at either standard housing temperature or at a thermoneutral ambient temperature, which significantly reduces the extent of cold stress. The new data presented here strongly suggests that, by itself, the housing temperature of mice can affect fundamental properties and functions of DCs. Therefore differences in basal levels of stress due to housing should be taken into consideration when interpreting experiments designed to evaluate the impact of additional variables, including other stressors on DC function.

Neural Correlates of Aggressive Behavior in Real Time: a Review of fMRI Studies of Laboratory Reactive Aggression

PubMed Central

Keedy, Sarah; Berman, Mitchell E.; Lee, Royce; Coccaro, Emil F.

2017-01-01

Purpose of review Aggressive behavior has adaptive value in many natural environments; however, it places substantial burden and costs on human society. For this reason, there has long been interest in understanding the neurobiological basis of aggression. This interest, and the flourishing of neuroimaging research in general, has spurred the development of a large and growing scientific literature on the topic. As a result, a neural circuit model of aggressive behavior has emerged that implicates interconnected brain regions that are involved in emotional reactivity, emotion regulation, and cognitive control. Recent findings Recently, behavioral paradigms that simulate provocative interactions have been adapted to neuroimaging protocols, providing an opportunity to directly probe the involvement of neural circuits in an aggressive interaction. Here we review neuroimaging studies of simulated aggressive interactions in research volunteers. We focus on studies that use a well-validated laboratory paradigm for reactive physical aggression and examine the neural correlates of provocation, retaliation, and evaluating punishment of an opponent. Summary Overall, the studies reviewed support the involvement of neural circuits that support emotional reactivity, emotion regulation, and cognitive control in aggressive behavior. Based on a synthesis of this literature, future research directions are discussed. PMID:29607288

Psycho-social stress, insomnia and temazepam: a sleep laboratory evaluation in a "general practice" sample.

PubMed

Beary, M D; Lacey, J H; Crutchfield, M B; Bhat, A V

1984-01-01

Taking a population of women most of whom were about to seek medication from their general practitioner for stress-induced insomnia, this sleep laboratory study examined--both electro -physiologically and psychologically--the immediate impact of temazepam, at normal prescribed dosage, on sleep. The study was double-blind, controlled with random allocation. Temazepam 20 mg, prepared as a liquid in a soft gelatin capsule, reduced sleep latency and prolonged total sleep time. A reduction in stage shifts to Stages I and II and a reduction in time spent in Stages 0 + I suggest more restful sleep. The sleep "architecture" (including REM/NREM cycling, total SWS and REM time) was relatively undisturbed. Temazepam would seem to be effective as a first-line hypnotic for short-term use in stressed patients.

An Apparatus to Deliver Mannitol Powder for Bronchial Provocation in Children Under Six Years Old.

PubMed

Tang, Patricia; Leung, Sharon S Y; Hor, Eleanor; Ruzycki, Conor A; Carrigy, Nicholas B; Finlay, Warren H; Brannan, John D; Devadason, Sunalene; Anderson, Sandra D; Sly, Peter D; Samnick, Kevin; Chan, Hak-Kim

2015-12-01

Currently bronchial provocation testing (BPT) using mannitol powder cannot be performed in children under 6 years. A primary reason is it is challenging for children at this age to generate a consistent inspiratory effort to inhale mannitol efficiently from a dry powder inhaler. A prototype system, which does not require any inhalation training from the pediatric subject, is reported here. It uses an external source of compressed air to disperse mannitol powder into a commercial holding chamber. Then the subject uses tidal breathing to inhale the aerosol. The setup consists of a commercially available powder disperser and Volumatic™ holding chamber. Taguchi experimental design was used to identify the effect of dispersion parameters (flow rate of compressed air, time compressed air is applied, mass of powder, and the time between dispersion and inhalation) on the fine particle dose (FPD). The prototype was tested in vitro using a USP throat connected to a next generation impactor. The aerosols from the holding chamber were drawn at 10 L/min. A scaling factor for estimating the provoking dose to induce a 15% reduction in forced expiratory volume in 1 second (FEV1) (PD15) was calculated using anatomical dimensions of the human respiratory tract at various ages combined with known dosing values from the adult BPT. Consistent and doubling FPDs were successfully generated based on the Taguchi experimental design. The FPD was reliable over a range of 0.8 (±0.09) mg to 14 (±0.94) mg. The calculated PD15 for children aged 1-6 years ranged from 7.1-30 mg. The FPDs generated from the proposed set up are lower than the calculated PD15 and therefore are not expected to cause sudden bronchoconstriction. A prototype aerosol delivery system has been developed that is consistently able to deliver doubling doses suitable for bronchial provocation testing in young children.

Laboratory Determination of Horizontal Stress in Cohesionless Soil.

DTIC Science & Technology

1983-01-01

in soft silty clay. The sheet piles were used for excavation support for the Oslo subway construction and the measurements of the lateral stresses 4...5.2. By sandwiching the stress cell between two butyl rubber diaphragms in the chamber, a uniform uniaxial stress could be applied to the 4 stress...October 1944, pp. 355-358. .4 162 Johannessen, I. J., "Test Section and Installation of Test Equipment, Oslo Subway ," Pro Brussels Confer- ence on

Laboratory Astrophysics White Paper: Summary of Laboratory Astrophysics Needs

NASA Technical Reports Server (NTRS)

2002-01-01

The NASA Laboratory Astrophysics Workshop (NASA LAW) met at NASA Ames Research Center from 1-3 May 2002 to assess the role that laboratory astrophysics plays in the optimization of NASA missions, both at the science conception level and at the science return level. Space missions provide understanding of fundamental questions regarding the origin and evolution of galaxies, stars, and planetary systems. In all of these areas the interpretation of results from NASA's space missions relies crucially upon data obtained from the laboratory. We stress that Laboratory Astrophysics is important not only in the interpretation of data, but also in the design and planning of future missions. We recognize a symbiosis between missions to explore the universe and the underlying basic data needed to interpret the data from those missions. In the following we provide a summary of the consensus results from our Workshop, starting with general programmatic findings and followed by a list of more specific scientific areas that need attention. We stress that this is a 'living document' and that these lists are subject to change as new missions or new areas of research rise to the fore.

Solid phase testing in the HLA laboratory: implications for organ allocation.

PubMed

Eckels, D D

2008-08-01

This piece was originally requested as a white paper from the Scientific and Clinical Affairs Committee of the American Society for Histocompatibility and Immunogenetics (ASHI), of which the author was then Chairman. Upon review by the ASHI Board of Directors and the Editors of their journal, it was considered too controversial for publication. It is intended to be provocative and controversial; it is not intended as a review of the literature. Though written with a decided 'American point of view', it is of importance that the issues facing US transplantation and laboratory testing efforts are shared to varying degrees by the international community, and who, unlike some of their American cousins, may be able to tolerate a spirited discussion. Sadly, we sometimes forget that dissent from dogma can be fun!

Test-retest Reliability in Reporting the Pain Induced by a Pain Provocation Test: Further Validation of a Novel Approach for Pain Drawing Acquisition and Analysis.

PubMed

Leoni, Diego; Falla, Deborah; Heitz, Carolin; Capra, Gianpiero; Clijsen, Ron; Egloff, Michele; Cescon, Corrado; Baeyens, Jean-Pierre; Barbero, Marco

2017-02-01

Pain drawings (PD) are frequently used in research to illustrate the pain response to pain provocation tests. However, there is a lack of data on the reliability in defining the extent and location of pain. We investigated the test-retest reliability in reporting an acute painful sensation induced by a pain provocation test using a novel approach for PD acquisition and analysis in healthy volunteers. Forty healthy volunteers participated. Each participant underwent 2 upper limb neurodynamic tests 1 (ULNT1), once to the point of pain onset (PO) and once until the point of submaximal pain (SP). After each ULNT1, participants completed 2 consecutive PD with an interval of 1 minute. Custom software was used to quantify the pain extent and analyze the pain overlap. The test-retest reliability of pain extent was examined using Intraclass Correlation Coefficient (ICC 2,1 ) and Bland-Altman plots. Pain location reliability was examined using the Jaccard similarity coefficient (JSC). The ICC values for PO and SP were 0.98 (95% CI: 0.96-0.99) and 0.97 (95% CI: 0.95-0.98), respectively. The mean difference and 95% limits of agreement (± 1.96 SD) in the Bland-Altman plots were 14 pixels (-1080;1110) for PO, and 145 (-1610;1900) for SP. The median JSCs (Q1;Q3) were 0.73 (0.64;0.80) for PO and 0.76 (0.65;0.79) for SP. Pain drawings is a reliable instrument to investigate pain extent and pain location in healthy individuals experiencing an acute painful sensation induced by a pain provocation test. © 2016 World Institute of Pain.

Adaptive Value of Phenological Traits in Stressful Environments: Predictions Based on Seed Production and Laboratory Natural Selection

PubMed Central

Glorieux, Cédric; Cuguen, Joel; Roux, Fabrice

2012-01-01

Phenological traits often show variation within and among natural populations of annual plants. Nevertheless, the adaptive value of post-anthesis traits is seldom tested. In this study, we estimated the adaptive values of pre- and post-anthesis traits in two stressful environments (water stress and interspecific competition), using the selfing annual species Arabidopsis thaliana. By estimating seed production and by performing laboratory natural selection (LNS), we assessed the strength and nature (directional, disruptive and stabilizing) of selection acting on phenological traits in A. thaliana under the two tested stress conditions, each with four intensities. Both the type of stress and its intensity affected the strength and nature of selection, as did genetic constraints among phenological traits. Under water stress, both experimental approaches demonstrated directional selection for a shorter life cycle, although bolting time imposes a genetic constraint on the length of the interval between bolting and anthesis. Under interspecific competition, results from the two experimental approaches showed discrepancies. Estimation of seed production predicted directional selection toward early pre-anthesis traits and long post-anthesis periods. In contrast, the LNS approach suggested neutrality for all phenological traits. This study opens questions on adaptation in complex natural environment where many selective pressures act simultaneously. PMID:22403624

MAOA-uVNTR genotype predicts interindividual differences in experimental aggressiveness as a function of the degree of provocation.

PubMed

Kuepper, Yvonne; Grant, Phillip; Wielpuetz, Catrin; Hennig, Juergen

2013-06-15

The MAOA-uVNTR has been suggested to play a role regarding aggression, however, results are inconsistent. We aimed at further elucidating potential effects of the MAOA-uVNTR on aggressiveness with respect to potential modulators: sex, experimental vs. trait aggressiveness and type of aggressiveness (proactive vs. reactive aggressiveness). We tested 239 healthy young adults (88 men/151 women). Participants were genotyped for the MAOA-uVNTR and performed a modified version of a competitive reaction time task - a commonly used and well established tool to elicit and measure aggressiveness. Furthermore, they completed a self-report scale measuring trait aggressiveness. We found a main effect of MAOA-uVNTR on a measure of reactive aggressiveness for both men and women, whereby the low-activity alleles of the MAOA-uVNTR were associated with substantially increased aggressive reactions (p<.05). This effect was unique for reactive aggressiveness. Measures of proactive aggressiveness or self reports were not associated with the MAOA-uVNTR-genotype. Our data are in line with earlier studies and indicate the MAOA-uVNTR-genotype to be specifically associated with measures of reactive impulsive experimental aggressiveness in healthy men and women. Furthermore the association between the MAOA-uVNTR genotype and aggressive responses increases in a fashion linear to the degree of provocation. This indicates that the low-functional alleles of the MAOA-uVNTR are not associated with increased aggressive behavior per se, but rather with an increased aggressive reactivity to provocation. Copyright © 2013 Elsevier B.V. All rights reserved.

The Novaco Anger Scale-Provocation Inventory (1994 version) in Dutch forensic psychiatric patients.

PubMed

Hornsveld, Ruud H J; Muris, Peter; Kraaimaat, Floris W

2011-12-01

We examined the psychometric properties of the Novaco Anger Scale-Provocation Inventory (NAS-PI, 1994 version) in Dutch violent forensic psychiatric patients and secondary vocational students. A confirmatory factor analysis of the subscale structure of the NAS was carried out, reliability was investigated, and relations were calculated between NAS-PI scores and other measures of personality traits and problem behaviors. The 3-subscale structure of the original NAS could not be confirmed. However, the internal consistency of the NAS and the PI was excellent, and the test-retest reliability of the NAS was good. The validity of the NAS and the PI was supported by a meaningful pattern of correlations with alternative measures of anger and personality traits. Forensic psychiatric outpatients displayed higher NAS scores than secondary vocational students, but inpatients scored even lower than this nonclinical control group. Our preliminary conclusion is that the NAS-PI is a valuable instrument for the assessment of anger in Dutch violent forensic psychiatric patients.

Stress-strain behaviour analysis of Middle Polish glacial tills from Warsaw (Poland) based on the interpretation of advanced field and laboratory tests

NASA Astrophysics Data System (ADS)

Bąkowska, Anna; Dobak, Dobak; Gawriuczenkow, Ireneusz; Kiełbasiński, Kamil; Szczepański, Tomasz; Trzciński, Jerzy; Wójcik, Emilia; Zawrzykraj, Piotr

2016-09-01

The selected parameters of the Wartanian and Odranian tills, with relation to their spatial occurrence, grain size distribution, mineralogical composition, matric suction and other physical characteristics, are presented. The assessment of the lithogenesis and stress history on the microstructure is attempted. The comparison of the compression and permeability characteristics from field and laboratory tests has been performed. Laboratory consolidation tests carried out with up to 20MPa vertical stress, revealed two yield stress values, one in the range of a couple hundreds kPa, the other in the range of a couple thousands kPa. Based on those results, the reliability of the soil preconsolidation assessment, with the use of the two different methods is discussed. The aspect of the triaxial strength reduction under the dynamic loading of diverse frequency and amplitude is raised. The research results depict a variety of possible geological-engineering characteristics, under the divergent constraints scenarios, of compression or strength weakening origin. The effects of the specialized research program will widen the possibilities of physio-mechanical and structural characterization of soils for geological-engineering purposes.

Neural stress reactivity relates to smoking outcomes and differentiates between mindfulness and cognitive-behavioral treatments.

PubMed

Kober, Hedy; Brewer, Judson A; Height, Keri L; Sinha, Rajita

2017-05-01

Stress and negative affect are known contributors to drug use and relapse, and several known treatments for addictions include strategies for managing them. In the current study, we administered a well-established stress provocation during functional magnetic resonance imaging (fMRI) to 23 participants who completed either mindfulness training (MT; N=11) or the American Lung Association's Freedom From Smoking (FFS; N=12), which is a cognitive-behavioral treatment (CBT) for smoking cessation. Across the entire sample, we found that stress reactivity in several brain regions including the amygdala and anterior/mid insula was related to reductions in smoking after treatment, as well as at 3-month post-treatment follow-up. Moreover, conjunction analysis revealed that these same regions also differentiated between treatment groups such that the MT group showed lower stress-reactivity compared to the FFS/CBT group. This suggests that reduction in stress reactivity may be one of the mechanisms that underlie the efficacy of MT in reducing smoking over time. The findings have important implications for our understanding of stress, the neural and psychological mechanisms that underlie mindfulness-based treatments, and for smoking cessation treatments more broadly. Copyright © 2016 Elsevier Inc. All rights reserved.

Does short-term exposure to mobile phone base station signals increase symptoms in individuals who report sensitivity to electromagnetic fields? A double-blind randomized provocation study.

PubMed

Eltiti, Stacy; Wallace, Denise; Ridgewell, Anna; Zougkou, Konstantina; Russo, Riccardo; Sepulveda, Francisco; Mirshekar-Syahkal, Dariush; Rasor, Paul; Deeble, Roger; Fox, Elaine

2007-11-01

Individuals with idiopathic environmental illness with attribution to electromagnetic fields (IEI-EMF) believe they suffer negative health effects when exposed to electromagnetic fields from everyday objects such as mobile phone base stations. This study used both open provocation and double-blind tests to determine if sensitive and control individuals experience more negative health effects when exposed to base station-like signals compared with sham. Fifty-six self-reported sensitive and 120 control participants were tested in an open provocation test. Of these, 12 sensitive and 6 controls withdrew after the first session. The remainder completed a series of double-blind tests. Subjective measures of well-being and symptoms as well as physiological measures of blood volume pulse, heart rate, and skin conductance were obtained. During the open provocation, sensitive individuals reported lower levels of well-being in both the global system for mobile communication (GSM) and universal mobile telecommunications system (UMTS) compared with sham exposure, whereas controls reported more symptoms during the UMTS exposure. During double-blind tests the GSM signal did not have any effect on either group. Sensitive participants did report elevated levels of arousal during the UMTS condition, whereas the number or severity of symptoms experienced did not increase. Physiological measures did not differ across the three exposure conditions for either group. Short-term exposure to a typical GSM base station-like signal did not affect well-being or physiological functions in sensitive or control individuals. Sensitive individuals reported elevated levels of arousal when exposed to a UMTS signal. Further analysis, however, indicated that this difference was likely to be due to the effect of order of exposure rather than the exposure itself.

Replication of heart rate variability provocation study with 2.4-GHz cordless phone confirms original findings.

PubMed

Havas, Magda; Marrongelle, Jeffrey

2013-06-01

This is a replication of a study that we previously conducted in Colorado with 25 subjects designed to test the effect of electromagnetic radiation generated by the base station of a cordless phone on heart rate variability (HRV). In this study, we analyzed the response of 69 subjects between the ages of 26 and 80 in both Canada and the USA. Subjects were exposed to radiation for 3-min intervals generated by a 2.4-GHz cordless phone base station (3-8 μW/cm²). A few participants had a severe reaction to the radiation with an increase in heart rate and altered HRV indicative of an alarm response to stress. Based on the HRV analyses of the 69 subjects, 7% were classified as being "moderately to very" sensitive, 29% were "little to moderately" sensitive, 30% were "not to little" sensitive and 6% were "unknown". These results are not psychosomatic and are not due to electromagnetic interference. Twenty-five percent of the subjects' self-proclaimed sensitivity corresponded to that based on the HRV analysis, while 32% overestimated their sensitivity and 42% did not know whether or not they were electrically sensitive. Of the 39 participants who claimed to experience some electrical hypersensitivity, 36% claimed they also reacted to a cordless phone and experienced heart symptoms and, of these, 64% were classified as having some degree of electrohypersensitivity (EHS) based on their HRV response. Novel findings include documentation of a delayed response to radiation. Orthostatic HRV testing combined with provocation testing may provide a diagnostic tool for some sufferers of EHS when they are exposed to electromagnetic emitting devices. The protocol used underestimates reaction to electromagnetic radiation for those who have a delayed autonomic nervous system reaction and it may under diagnose those who have adrenal exhaustion as their ability to mount a response to a stressor is diminished.

Natural History of Benign Nonimmediate Allergy to Beta-Lactams in Children: A Prospective Study in Retreated Patients After a Positive and a Negative Provocation Test.

PubMed

Tonson la Tour, Aude; Michelet, Marine; Eigenmann, Philippe A; Caubet, Jean-Christoph

2017-11-23

The drug provocation test (DPT) is considered as the gold standard to diagnose drug allergy and is particularly important in the diagnosis of nonimmediate beta-lactam (BL) allergy in children. The natural history of BL allergy remains unknown. Our main aim was to evaluate the natural history of nonimmediate BL hypersensitivity and the long-term tolerance acquisition, and our secondary objective was to determine the negative predictive value (NPV) of the DPT following a 2-day protocol. Children developing a benign rash while treated by BL were prospectively recruited at the Emergency Department of the Geneva University Hospital from 2006 to 2011 and challenged with the incriminated BL (initial diagnostic drug provocation test [idDPT]) following a 2-day protocol. In case of a positive idDPT, the patients underwent a follow-up drug provocation test (fuDPT) 3 years later. In case of a negative idDPT, we sent a questionnaire to assess tolerance of a subsequent treatment with the incriminated BL. Among the 18 children with a positive idDPT, 16 children (89%) had a negative fuDPT and 2 children developed a benign exanthema. Among those 16 children, 11 tolerated a subsequent treatment with the incriminated BL without any reaction, suggesting natural antibiotic tolerance acquisition. From another point of view, we found that the NPV of the DPT following a 2-day protocol was excellent at 96.7%. Our data strongly suggest that a fuDPT is safe and useful to assess tolerance acquisition in children with a confirmed benign nonimmediate BL allergy. In addition, our results support the use of a short DPT protocol (2 days), which led to a high NPV of 96.7% in our population, with a favorable benefit-risk balance. Copyright © 2017 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Relationship between ethanol and oxidative stress in laboratory and brewing yeast strains.

PubMed

Bleoanca, Iulia; Silva, Ana Rita Courelas; Pimentel, Catarina; Rodrigues-Pousada, Claudina; Menezes, Regina de Andrade

2013-12-01

Ethanol is a chemical stress factor that inhibits cellular growth and determines metabolic changes leading to reduction of cell viability during fermentation and yeast storage. To determine the effect of time, temperature and ethanol during storage of brewing yeasts we have monitored viability of cells stored for 72 h, at 6 °C or 12 °C, in the presence of various ethanol concentrations. Under the conditions tested, 6 °C is the most favourable temperature to store brewing yeast creams emphasizing the importance of a tight temperature control in the storage vessels. Because W210 is less resistant to storage in the presence of ethanol than W34/70, the optimal storage parameters obtained under our laboratory conditions vary significantly. The ale strain is sensitive to storage under ethanol concentrations higher than 5% (v/v) for more than 48 h at 6 °C whereas at the same temperature the lager strain tolerates ethanol up to 7.5% (v/v) for 72 h. Also, the viability assays indicate that the antioxidant protein Yap1 is an important factor to storage resistance of BY4741 laboratory strain. To investigate the molecular mechanisms underlying tolerance of brewing yeast strains to ethanol, we have performed phenotypic analysis, localization studies and have monitored the activation of antioxidant and protection genes as well as the intracellular contents of glycogen and trehalose. Overall, our data suggest that the ale strain W210 has a defective antioxidant defence system and that ethanol may induce the antioxidant defences as well as glycogen and trehalose protection mechanisms in laboratory and brewing yeast strains. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Sympathetic activity in patients with panic disorder at rest, under laboratory mental stress, and during panic attacks.

PubMed

Wilkinson, D J; Thompson, J M; Lambert, G W; Jennings, G L; Schwarz, R G; Jefferys, D; Turner, A G; Esler, M D

1998-06-01

The sympathetic nervous system has long been believed to be involved in the pathogenesis of panic disorder, but studies to date, most using peripheral venous catecholamine measurements, have yielded conflicting and equivocal results. We tested sympathetic nervous function in patients with panic disorder by using more sensitive methods. Sympathetic nervous and adrenal medullary function was measured by using direct nerve recording (clinical microneurography) and whole-body and cardiac catecholamine kinetics in 13 patients with panic disorder as defined by the DSM-IV, and 14 healthy control subjects. Measurements were made at rest, during laboratory stress (forced mental arithmetic), and, for 4 patients, during panic attacks occurring spontaneously in the laboratory setting. Muscle sympathetic activity, arterial plasma concentration of norepinephrine, and the total and cardiac norepinephrine spillover rates to plasma were similar in patients and control subjects at rest, as was whole-body epinephrine secretion. Epinephrine spillover from the heart was elevated in patients with panic disorder (P=.01). Responses to laboratory mental stress were almost identical in patient and control groups. During panic attacks, there were marked increases in epinephrine secretion and large increases in the sympathetic activity in muscle in 2 patients but smaller changes in the total norepinephrine spillover to plasma. Whole-body and regional sympathetic nervous activity are not elevated at rest in patients with panic disorder. Epinephrine is released from the heart at rest in patients with panic disorder, possibly due to loading of cardiac neuronal stores by uptake from plasma during surges of epinephrine secretion in panic attacks. Contrary to popular belief, the sympathetic nervous system is not globally activated during panic attacks.

Background music in the dissection laboratory: impact on stress associated with the dissection experience.

PubMed

Anyanwu, Emeka G

2015-06-01

Notable challenges, such as mental distress, boredom, negative moods, and attitudes, have been associated with learning in the cadaver dissection laboratory (CDL). The ability of background music (BM) to enhance the cognitive abilities of students is well documented. The present study was designed to investigate the impact of BM in the CDL and on stress associated with the dissection experience. After 8 wk of normal dissection without BM, various genres of BM were introduced into the cadaver dissection sessions of 260 medical and dental students for 3 wk. Feedback on the impact of BM on students in the CDL and students' attitude were accessed using a questionnaire. Psychological stress assessment was done using Psychological Stress Measure 9. Two batches of 30 students each were made to dissect same areas of the body for 2 h, one batch with BM playing and the other batch without. The same examination was given to both groups at the end. Over 90% of the participants expressed a desire to incorporate BM into the CDL; 87% of the sampled population that expressed love for music also reported BM to be a very useful tool that could be used to enhance learning conditions in the CDL. A strong positive relationship was established between love for music and its perception as a tool for learning in the CDL (P < 0.001). Students that studied under the influence of BM had significantly higher scores (P < 0.001) in the overall examination result. BM reduced the level of stress associated with the dissection experience by ∼33%. Copyright © 2015 The American Physiological Society.

Anxiolytic effects of a combination of Melissa officinalis and Valeriana officinalis during laboratory induced stress.

PubMed

Kennedy, David O; Little, Wendy; Haskell, Crystal F; Scholey, Andrew B

2006-02-01

Melissa officinalis (lemon balm) and Valeriana officinalis (valerian) have been used both traditionally and contemporaneously as mild sedatives, anxiolytics and hypnotics. Recent research has suggested that both may attenuate laboratory induced stress. As the two herbs are most often sold in combination with each other the current study assessed the anxiolytic properties of such a combination during laboratory-induced stress. In this double-blind, placebo-controlled, randomized, balanced cross-over experiment, 24 healthy volunteers received three separate single doses (600 mg, 1200 mg, 1800 mg) of a standardized product containing M. officinalis and V. officinalis extracts, plus a placebo, on separate days separated by a 7 day wash out period. Modulation of mood and anxiety were assessed during pre-dose and 1 h, 3 h and 6 h post-dose completions of a 20 min version of the Defined Intensity Stressor Simulation (DISS) battery. Cognitive performance on the four concurrent tasks of the battery was also assessed. The results showed that the 600 mg dose of the combination ameliorated the negative effects of the DISS on ratings of anxiety. However, the highest dose (1800 mg) showed an increase in anxiety that was less marked but which reached significance during one testing session. In addition, all three doses led to decrements in performance on the Stroop task module within the battery, and the two lower doses led to decrements on the overall score generated on the DISS battery. These results suggest that a combination of Melissa officinalis and Valeriana officinalis possesses anxiolytic properties that deserve further investigation. Copyright 2006 John Wiley & Sons, Ltd.

Evaluation of colonoscopic allergen provocation as a diagnostic tool in dogs with proven food hypersensitivity reactions.

PubMed

Allenspach, K; Vaden, S L; Harris, T S; Gröne, A; Doherr, M G; Griot-Wenk, M E; Bischoff, S C; Gaschen, F

2006-01-01

To evaluate the colonoscopic allergen provocation (COLAP) test as a new tool for the diagnosis of IgE-mediated food allergy. Oral food challenges as well as COLAP testing were performed in a colony of nine research dogs with proven immediate-type food allergic reactions. In addition, COLAP was performed in five healthy dogs. When compared with the oral challenge test, COLAP accurately determined 18 of 23 (73 per cent) positive oral challenge reactions (73 per cent) in dogs with food allergies and was negative in the healthy dogs. The accuracy of this new test may be higher than that for gastric sensitivity testing. Therefore, COLAP holds promise as a new test to confirm the diagnosis of suspect IgE-mediated food allergy in dogs.

Trait aggressiveness modulates neurophysiological correlates of laboratory-induced reactive aggression in humans.

PubMed

Krämer, Ulrike M; Büttner, Sarah; Roth, Gerhard; Münte, Thomas F

2008-08-01

Reactive aggression following provocation is a frequent form of human social behavior. The neural basis of reactive aggression, especially its control, remains poorly understood, however. We conducted an event-related potential (ERP) study using a competitive reaction time task that elicits aggression through provocation. Participants were selected from a larger sample because of extreme scores in trait aggressiveness, yielding high and low trait aggressive groups. As each trial in the task is separated into a decision phase, during which the punishment level for the opponent is set, and an outcome phase, during which the punishment is applied or received, we were able to disentangle provocation-related and evaluation-related modulations of the ERPs during the aggressive interaction. Specifically, we observed an enhanced frontal negativity during the decision phase under high provocation that was positively correlated with the participants' ability to refrain from retaliation. This held true for high trait aggressive participants only, pointing to a higher need for inhibitory and control processes in these people when provoked. During the outcome phase, we detected a mediofrontal negativity in loss compared to win trials, resembling previous ERP findings to negative feedback stimuli, which have been linked to the evaluation of an outcome's valence. This mediofrontal negativity was differentially pronounced in aggressive and nonaggressive participants: Nonaggressive participants showed only a slightly smaller mediofrontal negativity in win than in loss trials, suggesting that for them punishing the opponent had a similar negative valence as being punished.

A laboratory study of mean flow generation in rotating fluids by Reynolds stress gradients

NASA Astrophysics Data System (ADS)

McGuinness, D. S.; Boyer, D. L.; Fernando, H. J. S.

2001-06-01

Laboratory experiments were conducted that demonstrate that a mean azimuthal flow can be produced by introducing Reynolds stress gradients to a rotating fluid with zero initial mean flow. This mechanism may play a role in the generation of mean currents in coastal regions. The experiments entail the establishment of turbulence in a thin annular-shaped region centered within a cylindrical test cell through the use of a vertically oscillating grid. This region rests in a horizontal plane perpendicular to the vertical axis of the tank, and the entire system is placed on a turntable to simulate background rotation. Flow visualization techniques are used to depict qualitative features of the resulting flow field. Measurements of the mean and turbulent velocity fields are performed using a two-component laser-Doppler velocimeter. The results show how rectified currents (mean flows) can be generated via Reynolds stress gradients induced by periodic forcing of the grid. In the absence of background rotation, rectified flow is observed in the radial and vertical directions only. The presence of background rotation tends to organize these motions in that the flow tends to move parallel to the turbulent source, i.e., in the azimuthal direction, with the source (strong turbulence) located to the right, facing downstream. The influence of rotation on the Reynolds stresses and their gradients as well as on the ensuing mean flow is evaluated, and the observations are examined by considering individual contributions of the terms in the Reynolds-averaged momentum equations.

Creep Laboratory manual

NASA Astrophysics Data System (ADS)

Osgerby, S.; Loveday, M. S.

1992-06-01

A manual for the NPL Creep Laboratory, a collective name given to two testing laboratories, the Uniaxial Creep Laboratory and the Advanced High Temperature Mechanical Testing Laboratory, is presented. The first laboratory is devoted to uniaxial creep testing and houses approximately 50 high sensitivity creep machines including 10 constant stress cam lever machines. The second laboratory houses a low cycle fatigue testing machine of 100 kN capacity driven by a servo-electric actuator, five machines for uniaxial tensile creep testing of engineering ceramics at temperatures up to 1600C, and an electronic creep machine. Details of the operational procedures for carrying out uniaxial creep testing are given. Calibration procedures to be followed in order to comply with the specifications laid down by British standards, and to provide traceability back to the primary standards are described.

Does Short-Term Exposure to Mobile Phone Base Station Signals Increase Symptoms in Individuals Who Report Sensitivity to Electromagnetic Fields? A Double-Blind Randomized Provocation Study

PubMed Central

Eltiti, Stacy; Wallace, Denise; Ridgewell, Anna; Zougkou, Konstantina; Russo, Riccardo; Sepulveda, Francisco; Mirshekar-Syahkal, Dariush; Rasor, Paul; Deeble, Roger; Fox, Elaine

2007-01-01

Background Individuals with idiopathic environmental illness with attribution to electromagnetic fields (IEI-EMF) believe they suffer negative health effects when exposed to electromagnetic fields from everyday objects such as mobile phone base stations. Objectives This study used both open provocation and double-blind tests to determine if sensitive and control individuals experience more negative health effects when exposed to base station-like signals compared with sham. Methods Fifty-six self-reported sensitive and 120 control participants were tested in an open provocation test. Of these, 12 sensitive and 6 controls withdrew after the first session. The remainder completed a series of double-blind tests. Subjective measures of well-being and symptoms as well as physiological measures of blood volume pulse, heart rate, and skin conductance were obtained. Results During the open provocation, sensitive individuals reported lower levels of well-being in both the global system for mobile communication (GSM) and universal mobile telecommunications system (UMTS) compared with sham exposure, whereas controls reported more symptoms during the UMTS exposure. During double-blind tests the GSM signal did not have any effect on either group. Sensitive participants did report elevated levels of arousal during the UMTS condition, whereas the number or severity of symptoms experienced did not increase. Physiological measures did not differ across the three exposure conditions for either group. Conclusions Short-term exposure to a typical GSM base station-like signal did not affect well-being or physiological functions in sensitive or control individuals. Sensitive individuals reported elevated levels of arousal when exposed to a UMTS signal. Further analysis, however, indicated that this difference was likely to be due to the effect of order of exposure rather than the exposure itself. PMID:18007992

The Effect of the Laboratory Specimen on Fatigue Crack Growth Rate

NASA Technical Reports Server (NTRS)

Forth, S. C.; Johnston, W. M.; Seshadri, B. R.

2006-01-01

Over the past thirty years, laboratory experiments have been devised to develop fatigue crack growth rate data that is representative of the material response. The crack growth rate data generated in the laboratory is then used to predict the safe operating envelope of a structure. The ability to interrelate laboratory data and structural response is called similitude. In essence, a nondimensional term, called the stress intensity factor, was developed that includes the applied stresses, crack size and geometric configuration. The stress intensity factor is then directly related to the rate at which cracks propagate in a material, resulting in the material property of fatigue crack growth response. Standardized specimen configurations and experimental procedures have been developed for laboratory testing to generate crack growth rate data that supports similitude of the stress intensity factor solution. In this paper, the authors present laboratory fatigue crack growth rate test data and finite element analyses that show similitude between standard specimen configurations tested using the constant stress ratio test method is unobtainable.

Retrospective Comparison of Cardiac Testing and Results on Inpatients with Low Pretest Probability Compared with Moderate/High Pretest Probability for Coronary Artery Disease.

PubMed

Lear, Aaron; Huber, Merritt; Canada, Amy; Robertson, Jessica; Bosman, Evan; Zyzanski, Stephen

2018-01-01

To determine whether admission, and provocative stress testing of patients who have ruled out for acute coronary syndrome put patients with low-risk category for coronary artery disease (CAD) at risk for false-positive provocative stress testing and unnecessary coronary angiogram/imaging. A retrospective chart review was performed on patients between 30 and 70 years old, with no pre-existing diagnosis of CAD, admitted to observation or inpatient status chest pain or related complaints. Included patients were categorized based on Duke Clinical Score for pretest probability for CAD into either low-risk group, or moderate/high-risk group. The inpatient course was compared including whether provocative stress testing was performed; results of stress testing; whether patients underwent further coronary imaging; and what the results of the further imaging showed. 543 patients were eligible: 305 low pretest probability, and 238 moderate/high pretest probability. No difference was found in rate of stress testing relative risk (RR) = 1.01 (95% CI, 0.852 to 1.192; P = 0); rate of positive or equivocal stress tests between the 2 groups: RR = 0.653 (95% CI, 0.415 to 1.028; P = .07,). Low-pretest-probability patients had a lower likelihood of positive coronary imaging after stress test, RR = 0.061 (95% CI, 0.004 to 0.957; P = .001). Follow-up provocative testing of all patients admitted/observed after emergency department presentation with chest pain is unlikely to find CAD in patients with low pretest probability. Testing all low-probability patients puts them at increased risk for unnecessary invasive confirmatory testing. Further prospective testing is needed to confirm these retrospective results. © Copyright 2018 by the American Board of Family Medicine.

A comparison of mindfulness-based stress reduction and an active control in modulation of neurogenic inflammation

PubMed Central

Rosenkranz, Melissa A.; Davidson, Richard J.; MacCoon, Donal G.; Sheridan, John F.; Kalin, Ned H.; Lutz, Antoine

2012-01-01

Psychological stress is a major provocative factor of symptoms in chronic inflammatory conditions. In recent years, interest in addressing stress responsivity through meditation training in health-related domains has increased astoundingly, despite a paucity of evidence that reported benefits are specific to meditation practice. We designed the present study to rigorously compare an 8-week Mindfulness-Based Stress Reduction (MBSR) intervention to a well-matched active control intervention, the Health Enhancement Program (HEP) in ability to reduce psychological stress and experimentally-induced inflammation. The Trier Social Stress Test (TSST) was used to induce psychological stress and inflammation was produced using topical application of capsaicin cream to forearm skin. Immune and endocrine measures of inflammation and stress were collected both before and after MBSR training. Results show those randomized to MBSR and HEP training had comparable post-training stress-evoked cortisol responses, as well as equivalent reductions in self-reported psychological distress and physical symptoms. However, MBSR training resulted in a significantly smaller post-stress inflammatory response compared to HEP, despite equivalent levels of stress hormones. These results suggest behavioral interventions designed to reduce emotional reactivity may be of therapeutic benefit in chronic inflammatory conditions. Moreover, mindfulness practice, in particular, may be more efficacious in symptom relief than the well-being promoting activities cultivated in the HEP program. PMID:23092711

Preliminary evidence that acute stress moderates basal testosterone's association with retaliatory behavior.

PubMed

Prasad, Smrithi; Narayanan, Jayanth; Lim, Vivien K G; Koh, Gerald C H; Koh, David S Q; Mehta, Pranjal H

2017-06-01

A contribution to a special issue on Hormones and Human Competition. Testosterone is theorized to increase retaliation after social provocation. However, empirical evidence in support of these theories is mixed. The present research investigated whether acute stress causally suppresses testosterone's association with retaliation. We also explored sex differences in behavioral responses to acute stress. Thirty-nine participants (51.28% male) were randomly assigned to a high- or low-stress condition. Then participants engaged in 20 one-shot rounds of the ultimatum game, which was used to assess retaliatory behavioral responses to unfair treatment. Participants provided two saliva samples to measure testosterone and cortisol concentrations - one sample before the stress manipulation, and the second after the ultimatum game (20minutes post-stressor). Results revealed a positive association between basal testosterone and retaliation in the low-stress condition, but not in the high-stress condition. Further, cortisol concentrations increased in the high- compared to the low-stress condition, and these cortisol changes moderated the association between basal testosterone and retaliation. The associations between basal testosterone and retaliation under varying levels of stress were similar in men and women. However, there was a sex difference in behavioral responses to the stress manipulation that was independent of testosterone. In women, the high-stress condition reduced retaliation compared to the low-stress condition, whereas in men the opposite pattern emerged. Collectively, this study (i) provides preliminary evidence that experimentally manipulated stress blocks basal testosterone's association with retaliation, and (ii) reveals a sex difference in retaliation under varying levels of stress. Discussion focuses on mechanisms, limitations, and the need for follow-up studies with larger sample sizes. Copyright © 2016 Elsevier Inc. All rights reserved.

Constraint and cost of oxidative stress on reproduction: correlative evidence in laboratory mice and review of the literature

PubMed Central

2012-01-01

Background One central concept in evolutionary ecology is that current and residual reproductive values are negatively linked by the so-called cost of reproduction. Previous studies examining the nature of this cost suggested a possible involvement of oxidative stress resulting from the imbalance between pro- and anti-oxidant processes. Still, data remain conflictory probably because, although oxidative damage increases during reproduction, high systemic levels of oxidative stress might also constrain parental investment in reproduction. Here, we investigated variation in oxidative balance (i.e. oxidative damage and antioxidant defences) over the course of reproduction by comparing female laboratory mice rearing or not pups. Results A significant increase in oxidative damage over time was only observed in females caring for offspring, whereas antioxidant defences increased over time regardless of reproductive status. Interestingly, oxidative damage measured prior to reproduction was negatively associated with litter size at birth (constraint), whereas damage measured after reproduction was positively related to litter size at weaning (cost). Conclusions Globally, our correlative results and the review of literature describing the links between reproduction and oxidative stress underline the importance of timing/dynamics when studying and interpreting oxidative balance in relation to reproduction. Our study highlights the duality (constraint and cost) of oxidative stress in life-history trade-offs, thus supporting the theory that oxidative stress plays a key role in life-history evolution. PMID:23268929

Evaluation of ability of reference toxicity tests to identify stress in laboratory populations of the amphipod Hyalella azteca

USGS Publications Warehouse

McNulty, E.W.; Dwyer, F.J.; Ellersieck, Mark R.; Greer, E.I.; Ingersoll, C.G.; Rabeni, C.F.

1999-01-01

Standard methods for conducting toxicity tests imply that the condition of test organisms can be established using reference toxicity tests. However, only a limited number of studies have evaluated whether reference toxicity tests can actually be used to determine if organisms are in good condition at the start of a test. We evaluated the ability of reference toxicants to identify stress associated with starvation in laboratory populations of the amphipod Hyalella azteca using acute toxicity tests and four reference toxicants: KCl, CdCl2, sodium pentachlorophenate (NaPCP), and carbaryl. Stress associated with severe starvation was observed with exposure of amphipods to carbaryl or NaPCP but not with exposure to KCl or CdCl2 (i.e., lower LC50 with severe starvation). Although the LC50s for NaPCP and carbaryl were statistically different between starved and fed amphipods, this difference may not be biologically significant given the variability expected in acute lethality tests. Stress associated with sieving, heat shock, or cold shock of amphipods before the start of a test was not evident with exposure to carbaryl or KCl as reference toxicants. The chemicals evaluated in this study provided minimal information about the condition of the organisms used to start a toxicity test. Laboratories should periodically perform reference toxicity tests to assess the sensitivity of life stages or strains of test organisms. However, use of other test acceptability criteria required in standard methods such as minimum survival, growth, or reproduction of organisms in the control treatment at the end of a test, provides more useful information about the condition of organisms used to start a test compared to data generated from reference toxicity tests.

Sex and stress: Men and women show different cortisol responses to psychological stress induced by the Trier social stress test and the Iowa singing social stress test.

PubMed

Reschke-Hernández, Alaine E; Okerstrom, Katrina L; Bowles Edwards, Angela; Tranel, Daniel

2017-01-02

Acute psychological stress affects each of us in our daily lives and is increasingly a topic of discussion for its role in mental illness, aging, cognition, and overall health. A better understanding of how such stress affects the body and mind could contribute to the development of more effective clinical interventions and prevention practices. Over the past 3 decades, the Trier Social Stress Test (TSST) has been widely used to induce acute stress in a laboratory setting based on the principles of social evaluative threat, namely, a judged speech-making task. A comparable alternative task may expand options for examining acute stress in a controlled laboratory setting. This study uses a within-subjects design to examine healthy adult participants' (n = 20 men, n = 20 women) subjective stress and salivary cortisol responses to the standard TSST (involving public speaking and math) and the newly created Iowa Singing Social Stress Test (I-SSST). The I-SSST is similar to the TSST but with a new twist: public singing. Results indicated that men and women reported similarly high levels of subjective stress in response to both tasks. However, men and women demonstrated different cortisol responses; men showed a robust response to both tasks, and women displayed a lesser response. These findings are in line with previous literature and further underscore the importance of examining possible sex differences throughout various phases of research, including design, analysis, and interpretation of results. Furthermore, this nascent examination of the I-SSST suggests a possible alternative for inducing stress in the laboratory. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Adenosine bronchial provocation with computerized wheeze detection in young infants with prolonged cough: correlation with long-term follow-up.

PubMed

Bentur, Lea; Beck, Raphael; Berkowitz, Drora; Hasanin, Jamal; Berger, Irit; Elias, Nael; Gavriely, Noam

2004-10-01

Chronic cough in babies is often associated with bronchial hyperreactivity (BHR). The objective documentation of BHR in babies is difficult, and acoustic methods have been described (provocative concentration of a substance causing wheeze) for conducting bronchial provocation tests (BPTs). We conducted a study to evaluate automatic computerized wheeze detection (CWD) in determining BHR in young infants with prolonged cough, and its correlation with the subsequent development of wheezing. Infants aged < 24 months with prolonged cough (ie, > 2 months) underwent acoustic BPTs with the response determined by CWD and auscultation by a physician. Telephone interviews with parents were conducted after 1 month and yearly for the next 3 years. A total of 28 infants who were 4 to 24 months old with prolonged cough were included in the study. Twenty of these infants (71.4%) had BHR as determined by a positive acoustic BPT result. In 11 of these 20 tests, the CWD occurred earlier, and in 9 tests it occurred at the same step as auscultation by a physician. Rhonchi or whistles often preceded wheezes. Seventeen of the 20 patients with BHR completed 3 years of follow-up. Of these, 14 had recurrent episodes of wheezing and shortness of breath, and 3 were well. Six of the eight adenosine-negative patients completed 3 years of follow-up and had no symptoms of BHR. Acoustic BPT is a technically feasible test for the detection of BHR in young infants. CWD provides an earlier detection of wheeze than stethoscope auscultation. In our group of infants, a positive acoustic BPT result had high correlation with symptoms compatible with BHR over the next 3 years.

Hyperventilation and cold-pressor stress echocardiography combined with automated functional imaging non-invasively detected vasospastic angina

PubMed Central

Suzuki, Kengo; Akashi, Yoshihiro J; Mizukoshi, Kei; Kou, Seisyou; Takai, Manabu; Izumo, Masaki; Shimozato, Takashi; Hayashi, Akio; Ohtaki, Eiji; Nobuoka, Sachihiko; Miyake, Fumihiko

2010-01-01

A 47-year-old male presented with chest discomfort while sleeping. The patient was suspected of having vasospastic angina (VSA) and underwent hyperventilation and cold-pressor stress echocardiography. No chest pain, ECG changes or decreased wall motion was found. However, automated function imaging (AFI) showed decreased peak systolic strain at the apex and postsystolic shortening at both the apex and inferior wall, which was not found before the test. The provocation test revealed 99% stenosis in the right coronary artery #2 at a dose of 50 μg acetylcholine and 90% stenosis in the left coronary artery #8 at a dose of 100 μg. The patient was thus diagnosed as having VSA. The present case demonstrates the usefulness of AFI combined with hyperventilation and cold-pressor stress echocardiography as a screening examination for VSA. PMID:22798093

[The severity of gestational diabetes mellitus affects microvascular dysfunction measured three years after pregnancy that may be related to increased oxidative stress].

PubMed

Horváth, Eszter Mária; Mágenheim, Rita; Domján, Beatrix Annamária; Ferencz, Viktória; Tänczer, Tímea; Szabó, Eszter; Benkő, Rita; Szabó, Csaba; Tabák, Ádám; Somogyi, Anikó

2015-11-22

Oxidative-nitrative stress and poly(ADP-ribose) polymerase activation observed in gestational diabetes may play role in the increased cardiovascular risk in later life. The present study aimed to examine the influence of the severity of previous gestational diabetes (insulin need) on vascular function three years after delivery. Furthermore, the authors investigated the relation of vascular function with oxidative-nitrative stress and poly(ADP-ribose) polymerase activation. Macrovascular function was measured by applanation tonometry; microvascular reactivity was assessed by provocation tests during Laser-Doppler flowmetry in 40 women who had gestational diabetes 3 years before the study. Oxidative-nitrative stress and poly(ADP-ribose) polymerase activity in blood components were determined by colorimetry and immunohistochemistry. Three years after insulin treated gestational diabetes impaired microvascular function and increased oxidative stress was observed compared to mild cases. The severity of previous gestational diabetes affects microvascular dysfunction that is accompanied by elevated oxidative stress. Nitrative stress and poly(ADP-ribose) polymerase activity correlates with certain vascular factors not related to the severity of the disease.

Centralization as a predictor of provocation discography results in chronic low back pain, and the influence of disability and distress on diagnostic power.

PubMed

Laslett, Mark; Oberg, Birgitta; Aprill, Charles N; McDonald, Barry

2005-01-01

The "centralization phenomenon" (CP) is the progressive retreat of referred pain towards the spinal midline in response to repeated movement testing (a McKenzie evaluation). A previous study suggested that it may have utility in the clinical diagnosis of discogenic pain and may assist patient selection for discography and specific treatments for disc pain. Estimation of the diagnostic predictive power of centralization and the influence of disability and patient distress on diagnostic performance, using provocation discography as a criterion standard for diagnosis, in chronic low back pain patients. This study was a prospective, blinded, concurrent, reference standard-related validity design carried out in a private radiology clinic specializing in diagnosis of chronic spinal pain. Consecutive patients with persistent low back pain were referred to the study clinic by orthopedists and other medical specialists for interventional radiological diagnostic procedures. Patients were typically disabled and displayed high levels of psychosocial distress. The sample included patients with previous lumbar surgery, and most had unsuccessful conservative therapies previously. results of provocation discography. The CP. Psychometric evaluation: Roland-Morris, Zung, Modified Somatic Perception questionnaires, Distress Risk Assessment Method, and 100-mm visual analog scales for pain intensity. Patients received a single physical therapy examination, followed by lumbar provocation discography. Sensitivity, specificity, and likelihood ratios of the CP were estimated in the group as a whole and in subgroups defined by psychometric measures. A total of 107 patients received the clinical examination and discography at two or more levels and post-discography computed tomography. Thirty-eight could not tolerate a full physical examination and were excluded from the main analysis. Disability and pain intensity ratings were high, and distress was common. Sensitivity, specificity, and

The development of a non-invasive behavioral model of thermal heat stress in laboratory mice (Mus musculus).

PubMed

Mufford, J T; Paetkau, M J; Flood, N J; Regev-Shoshani, G; Miller, C C; Church, J S

2016-08-01

Many behavioral and physiological studies of laboratory mice employ invasive methods such as radio telemetry to measure key aspects of behavior and physiology. Radio telemetry requires surgical implants, which may impact mouse health and behavior, and thus reduce the reliability of the data collected. We developed a method to measure key aspects of thermoregulatory behavior without compromising animal welfare. We examined the thermoregulatory response to heat stress in a custom-built arena that permitted the use of simultaneous and continuous infrared thermography (IRT) and video capture. This allowed us to measure changes in surface body temperature and determine total distance traveled using EthoVision XT animal tracking software. Locomotor activity and surface body temperature differed between heat-stressed mice and mice kept within their thermal comfort zone. The former had an increase in surface body temperature and a decline in locomotor activity, whereas the latter had a stable surface body temperature and showed greater activity levels. Surface body temperature and locomotor activity are conventionally quantified by measurements taken at regular intervals, which limit the use and accuracy of the data. We obtained data of high resolution (i.e., recorded continuously) and accuracy that allowed for the examination of key physiological measurements such as energy expenditure and peripheral vasomotor tone. This novel experimental method for studying thermoregulatory behavior in mice using non-invasive tools has advantages over radio-telemetry and represents an improvement in laboratory animal welfare. Copyright © 2015 Elsevier B.V. All rights reserved.

Observations of the Kaiser effect under multiaxial stress states: Implications for its use in determining in situ stress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holcomb, D.J.

1993-10-08

Experimental tests of the Kaiser effect, the stress-history dependence of acoustic emission production, show that interactions between principal stresses cannot be ignored as is commonly done when trying to use the Kaiser effect to determine in situ stress. Experimental results obtained under multiaxial stress states are explained in terms of a qualitative model. The results show that the commonly-used technique of loading uniaxially along various directions to determine stress history must be reevaluated as it cannot be justified in terms of the laboratory experiments. One possible resolution of the conflict between laboratory and field results is that the Kaiser effectmore » phenomenon observed in cores retrieved from the earth is not the same phenomenon as is observed in rock loaded under laboratory conditions.« less

Tacrine is implicated in oxidative stress in the laboratory guinea pig model.

PubMed

Kracmarova, Alzbeta; Bandouchova, Hana; Pikula, Jiri; Pohanka, Miroslav

2012-01-01

Tacrine was the first acetylcholinesterase inhibitor approved for the treatment of Alzheimer disease. The compound is not available for therapeutic purposes as it was withdrawn due to hepatotoxicity of its metabolites. The hepatotoxicity can be decreased by alternative ways of drug administration avoiding thus the first pass effect. The present study is aimed to investigate the influence of intramuscularly administrated tacrine on oxidative stress. Laboratory guinea pigs were exposed to tacrine at doses of 0-800 μg/kg. The animals were euthanized 1 and 24 hours after the exposure. Parameters such as ferric reducing antioxidant power (FRAP), thiobarbituric acid reactive substances (TBARS), carbonylated proteins, caspase 3 activity, superoxide dismutase activity and glutathione reductase activity were assessed in the frontal, temporal and occipital lobe, cerebellum, liver, spleen, heart, and kidney. Moreover, levels of glucose, total and HDL cholesterol forms, triglycerides, blood urea nitrogen, creatinine, total bilirubin, total protein, albumin and activities of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and lactate dehydrogenase were assessed in plasma samples. Activities of the enzymatic markers, level of carbonylated proteins in organs and levels of biochemical markers in plasma were only slightly influenced by tacrine. Dose-dependent elevation of the FRAP value was recognized in the brain tissues and the liver. The TBARS value was increased in the kidney and heart 1 and 24 hours, respectively, after exposure. In the study, the effect of tacrine on markers of oxidative stress was proved. Possible positive effects of tacrine on the antioxidant defence in the brain tissue were discussed.

Noninvasive ergonovine maleate provocative testing for coronary artery spasm: the need for routine thallium-201 imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shanes, J.G.; Krone, R.J.; Fisher, K.

1983-01-01

We administered ergonovine and used both electrocardiographic monitoring and thallium-/sup 201/ (/sup 201/Tl) imaging to detect reversible ischemia in 100 patients. Patients already established as having coronary artery spasm and those with nonbypassed, proximal, high-grade coronary artery stenosis were excluded. No complication occurred in any patient. The use of thallium imaging in addition to electrocardiographic monitoring resulted in a higher degree of sensitivity than did ECG monitoring alone. Fourteen patients demonstrated evidence of coronary artery spasm as documented by /sup 201/Tl imaging but of the 14, significant ECG changes occurred in only 50%, and classic ST segment elevation in 21%.more » Thus, in carefully selected patients the noninvasive provocation of coronary spasm can be accomplished safely, but ECG monitoring must be combined with thallium-/sup 201/ imaging to achieve an acceptable degree of sensitivity.« less

Laboratory constraints on models of earthquake recurrence

NASA Astrophysics Data System (ADS)

Beeler, N. M.; Tullis, Terry; Junger, Jenni; Kilgore, Brian; Goldsby, David

2014-12-01

In this study, rock friction "stick-slip" experiments are used to develop constraints on models of earthquake recurrence. Constant rate loading of bare rock surfaces in high-quality experiments produces stick-slip recurrence that is periodic at least to second order. When the loading rate is varied, recurrence is approximately inversely proportional to loading rate. These laboratory events initiate due to a slip-rate-dependent process that also determines the size of the stress drop and, as a consequence, stress drop varies weakly but systematically with loading rate. This is especially evident in experiments where the loading rate is changed by orders of magnitude, as is thought to be the loading condition of naturally occurring, small repeating earthquakes driven by afterslip, or low-frequency earthquakes loaded by episodic slip. The experimentally observed stress drops are well described by a logarithmic dependence on recurrence interval that can be cast as a nonlinear slip predictable model. The fault's rate dependence of strength is the key physical parameter. Additionally, even at constant loading rate the most reproducible laboratory recurrence is not exactly periodic, unlike existing friction recurrence models. We present example laboratory catalogs that document the variance and show that in large catalogs, even at constant loading rate, stress drop and recurrence covary systematically. The origin of this covariance is largely consistent with variability of the dependence of fault strength on slip rate. Laboratory catalogs show aspects of both slip and time predictability, and successive stress drops are strongly correlated indicating a "memory" of prior slip history that extends over at least one recurrence cycle.

Aggregated data from two double-blind base station provocation studies comparing individuals with idiopathic environmental intolerance with attribution to electromagnetic fields and controls.

PubMed

Eltiti, Stacy; Wallace, Denise; Russo, Riccardo; Fox, Elaine

2015-02-01

Data from two previous studies were aggregated to provide a statistically powerful test of whether exposure to electromagnetic fields (EMFs) produced by telecommunication base stations negatively affects well-being in individuals who report idiopathic environmental illness with attribution to electromagnetic fields (IEI-EMF) and control participants. A total of 102 IEI-EMF and 237 controls participated in open provocation trials and 88 IEI-EMF and 231 controls went on to complete double-blind trials in which they were exposed to EMFs from a base station emitting either a Global System for Mobile Communication and Universal Mobile Telecommunications System or a Terrestrial Trunked Radio Telecommunications System signal. Both experiments included a comparison sham condition. Visual analog and symptom scales measured subjective well-being. Results showed that IEI-EMF participants reported lower levels of well-being during real compared to sham exposure during open provocation, but not during double-blind trials. Additionally, participants reported lower levels of well-being during high compared to low load trials and this did not interact with radiofrequency-EMF exposure. These findings are consistent with a growing body of literature indicating there is no causal relationship between short-term exposure to EMFs and subjective well-being in members of the public whether or not they report perceived sensitivity to EMFs. © 2015 Wiley Periodicals, Inc.

Simulating thermal stress features on hot planetary surfaces in vacuum at high temperature facility in the PEL laboratory

NASA Astrophysics Data System (ADS)

Maturilli, A.; Ferrari, S.; Helbert, J.; D'Incecco, P.; D'Amore, M.

2011-12-01

In the Planetary Emissivity Laboratory (PEL) at the Institute for Planetary Research of the German Aerospace Center (DLR) in Berlin, we set-up a simulation chamber for the spectroscopic investigation of minerals separates under Mercurial conditions. The chamber can be evacuated to 10-4 bar and the target samples heated to 700 K within few minutes, thanks to the innovative inductive heating system. While developing the protocol for the high temperature spectroscopy measurements we discovered interesting "morphologies" on the sample surfaces. The powders are poured into stainless steel cups of 50 mm internal diameter, 8 mm height and 3 mm depth, having a 5 mm thick base (thus leaving 3 mm free space for the minerals), and rim 1 mm thick. We selected several minerals of interest for Mercurial surface composition and for each of them we analyzed various grain size separates, to study the influence of grain dimensions to the process of thermal stressing. We observed that for the smaller grain size separate (0-25 μm) the thermal stress mainly induces large depressions and fractures, while on larger grain sizes (125-250 μm) small depressions and a cratered surface. Our current working hypothesis is that these features are mainly caused by thermal stress induced by a radiatively quickly cooling surface layer covering the much hotter bulk material. Further investigation is ongoing to understand the processes better. The observed morphologies exhibit surprising similarities to features observed at planetary scale size for example on Mercury and even on Venus. Especially the high resolution images provided currently from MESSENGER'S Mercury Dual Imaging System (MDIS) instrument has revealed plains dominated by polygonal fractures whose origin still have to be determined. Our laboratory analogue studies might in the future provide some insight into the processes creating those features

Validation of a Hybrid Microwave-Optical Monitor to Investigate Thermal Provocation in the Microvasculature.

PubMed

Al-Armaghany, Allann; Tong, Kenneth; Highton, David; Leung, Terence S

2016-01-01

We have previously developed a hybrid microwave-optical system to monitor microvascular changes in response to thermal provocation in muscle. The hybrid probe is capable of inducing deep heat from the skin surface using mild microwaves (1-3 W) and raises the tissue temperature by a few degrees Celsius. This causes vasodilation and the subsequent increase in blood volume is detected by the hybrid probe using near infrared spectroscopy. The hybrid probe is also equipped with a skin cooling system which lowers the skin temperature while allowing microwaves to warm up deeper tissues. The hybrid system can be used to assess the condition of the vasculature in response to thermal stimulation. In this validation study, thermal imaging has been used to assess the temperature distribution on the surface of phantoms and human calf, following microwave warming. The results show that the hybrid system is capable of changing the skin temperature with a combination of microwave warming and skin cooling. It can also detect thermal responses in terms of changes of oxy/deoxy-hemoglobin concentrations.

Individual differences in cognitive reappraisal usage modulate the time course of brain activation during symptom provocation in specific phobia

PubMed Central

2013-01-01

Background Extinction learning is proposed to be one key mechanism of action underlying exposure-based cognitive-behavioral therapy (CBT) in specific phobia. Beyond that, cognitive reappraisal, one important strategy to regulate negative emotions, is a crucial component of CBT interventions, but has been disregarded in previous studies investigating neural change processes in specific phobia. The aim of this study was to investigate the association of individual differences in habitual/dispositional cognitive reappraisal usage and the time course of brain activation during phobic stimulation in specific phobia. Methods Dental phobic patients and healthy control subjects participated in a functional magnetic resonance imaging (fMRI) study whilst being confronted with phobic, disgust, fear and neutral pictures. Individual differences in cognitive reappraisal usage were assessed via a self-report questionnaire and correlated with activation decreases over the course of time. Results Phobic individuals with higher dispositional cognitive reappraisal scores showed a more pronounced activation decline in the right dorsomedial prefrontal cortex (dmPFC) which might be associated with a diminution of explicit cognitive emotion regulation over the course of time. Less decrease of activation in the right ventromedial prefrontal cortex (vmPFC) and the lateral orbitofrontal cortex (lOFC) over time in subjects with higher cognitive reappraisal scores might be related to a stronger automatic regulation of emotions or even emotional relearning. Additionally, phobic subjects compared with healthy controls showed a stronger habituation of the left dmPFC over the course of symptom provocation. Conclusions The results of this study show for the first time that individual differences in cognitive reappraisal usage are associated with the time course of brain activation during symptom provocation in specific phobia. Additionally, the present study gives first indications for the

Heart rate variability indicates emotional value during pro-social economic laboratory decisions with large external validity.

PubMed

Fooken, Jonas

2017-03-10

The present study investigates the external validity of emotional value measured in economic laboratory experiments by using a physiological indicator of stress, heart rate variability (HRV). While there is ample evidence supporting the external validity of economic experiments, there is little evidence comparing the magnitude of internal levels of emotional stress during decision making with external stress. The current study addresses this gap by comparing the magnitudes of decision stress experienced in the laboratory with the stress from outside the laboratory. To quantify a large change in HRV, measures observed in the laboratory during decision-making are compared to the difference between HRV during a university exam and other mental activity for the same individuals in and outside of the laboratory. The results outside the laboratory inform about the relevance of laboratory findings in terms of their relative magnitude. Results show that psychologically induced HRV changes observed in the laboratory, particularly in connection with social preferences, correspond to large effects outside. This underscores the external validity of laboratory findings and shows the magnitude of emotional value connected to pro-social economic decisions in the laboratory.

Graphing techniques for materials laboratory using Excel

NASA Technical Reports Server (NTRS)

Kundu, Nikhil K.

1994-01-01

Engineering technology curricula stress hands on training and laboratory practices in most of the technical courses. Laboratory reports should include analytical as well as graphical evaluation of experimental data. Experience shows that many students neither have the mathematical background nor the expertise for graphing. This paper briefly describes the procedure and data obtained from a number of experiments such as spring rate, stress concentration, endurance limit, and column buckling for a variety of materials. Then with a brief introduction to Microsoft Excel the author explains the techniques used for linear regression and logarithmic graphing.

The effect of a single session of short duration biofeedback-induced deep breathing on measures of heart rate variability during laboratory-induced cognitive stress: a pilot study.

PubMed

Prinsloo, Gabriell E; Derman, Wayne E; Lambert, Michael I; Laurie Rauch, H G

2013-06-01

This study examines the acute effect of heart rate variability (HRV) biofeedback on HRV measures during and immediately after biofeedback and during the following laboratory-induced stress. Eighteen healthy males exposed to work-related stress were randomised into an HRV biofeedback group (BIO) or a comparative group (COM). Subjects completed a modified Stroop task before (Stroop 1) and after (Stroop 2) the intervention. Both groups had similar physiological responses to stress in Stroop 1. In Stroop 2, the COM group responded similarly to the way they did to Stroop 1: respiratory frequency (RF) and heart rate (HR) increased, RMSSD and high frequency (HF) power decreased or had a tendency to decrease, while low frequency (LF) power showed no change. The BIO group responded differently in Stroop 2: while RF increased and LF power decreased, HR, RMSSD and HF power showed no change. In the BIO group, RMSSD was higher in Stroop 2 compared to Stroop 1. In conclusion, HRV biofeedback induced a short term carry-over effect during both the following rest period and laboratory-induced stress suggesting maintained HF vagal modulation in the BIO group after the intervention, and maintained LF vagal modulation in the COM group.

Perplexities and Provocations of Eating Disorders

ERIC Educational Resources Information Center

Halmi, Katherine A.

2009-01-01

Background: Etiological hypotheses of eating disorders, anorexia nervosa and bulimia nervosa have not produced informative research for predictably effective treatment. Methods: The rationale for applying a model of allostasis, a dysregulation of reward circuits with activation of brain and hormonal stress responses to maintain apparent stability,…

Effects of interpersonal violence-related post-traumatic stress disorder (PTSD) on mother and child diurnal cortisol rhythm and cortisol reactivity to a laboratory stressor involving separation.

PubMed

Cordero, Maria I; Moser, Dominik A; Manini, Aurelia; Suardi, Francesca; Sancho-Rossignol, Ana; Torrisi, Raffaella; Rossier, Michel F; Ansermet, François; Dayer, Alexandre G; Rusconi-Serpa, Sandra; Schechter, Daniel S

2017-04-01

Women who have experienced interpersonal violence (IPV) are at a higher risk to develop posttraumatic stress disorder (PTSD), with dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis and impaired social behavior. Previously, we had reported impaired maternal sensitivity and increased difficulty in identifying emotions (i.e. alexithymia) among IPV-PTSD mothers. One of the aims of the present study was to examine maternal IPV-PTSD salivary cortisol levels diurnally and reactive to their child's distress in relation to maternal alexithymia. Given that mother-child interaction during infancy and early childhood has important long-term consequences on the stress response system, toddlers' cortisol levels were assessed during the day and in response to a laboratory stressor. Mothers collected their own and their 12-48month-old toddlers' salivary samples at home three times: 30min after waking up, between 2-3pm and at bedtime. Moreover, mother-child dyads participated in a 120-min laboratory session, consisting of 3 phases: baseline, stress situation (involving mother-child separation and exposure to novelty) and a 60-min regulation phase. Compared to non-PTSD controls, IPV-PTSD mothers - but not their toddlers, had lower morning cortisol and higher bedtime cortisol levels. As expected, IPV-PTSD mothers and their children showed blunted cortisol reactivity to the laboratory stressor. Maternal cortisol levels were negatively correlated to difficulty in identifying emotions. Our data highlights PTSD-IPV-related alterations in the HPA system and its relevance to maternal behavior. Toddlers of IPV-PTSD mothers also showed an altered pattern of cortisol reactivity to stress that potentially may predispose them to later psychological disorders. Copyright © 2017 Elsevier Inc. All rights reserved.

Linking daily stress processes and laboratory-based heart rate variability in a national sample of midlife and older adults

PubMed Central

Sin, Nancy L.; Sloan, Richard P.; McKinley, Paula S.; Almeida, David M.

2015-01-01

Objective This study evaluates the associations between people’s trait-like patterns of stress in daily life (stressor frequency, perceived stressor severity, affective reactivity to stressors, and negative affect) and laboratory-assessed heart rate variability (HRV). Methods Data were collected from 909 participants ages 35-85 in the Midlife in the United States Study. Participants reported negative affect and minor stressful events during telephone interviews on eight consecutive evenings. On a separate occasion, HRV was measured from electrocardiograph recordings taken at rest during a laboratory-based psychophysiology protocol. Regression models were used to evaluate the associations between daily stress processes and 3 log-transformed HRV indices: standard deviation of RR intervals (SDRR), root mean square of successive differences (RMSSD), and high-frequency power (HF-HRV). Analyses were adjusted for demographics, body mass index, comorbid conditions, medications, physical activity, and smoking. Results Stressor frequency was unrelated to HRV (r-values ranging from −0.04 to −0.01, p’s > 0.20). However, people with greater perceived stressor severity had lower resting SDRR (fully-adjusted B [SE] = −0.05 [0.02]), RMSSD (−0.08 [0.03]), and HF-HRV (−0.16 [0.07]). Individuals with more pronounced affective reactivity to stressors also had lower levels of all 3 HRV indices (SDRR: B [SE] = −0.28 [0.14]; RMSSD: −0.44 [0.19]; HF-HRV: −0.96 [0.37]). Furthermore, aggregated daily negative affect was linked to reduced RMSSD (B [SE] = −0.16 [0.08]) and HF-HRV (−0.35 [0.15]). Conclusions In a national sample, individual differences in daily negative affect and responses to daily stressors were more strongly related to cardiovascular autonomic regulation than the frequency of such stressors. PMID:26867082

Laboratory constraints on models of earthquake recurrence

USGS Publications Warehouse

Beeler, Nicholas M.; Tullis, Terry; Junger, Jenni; Kilgore, Brian D.; Goldsby, David L.

2014-01-01

In this study, rock friction ‘stick-slip’ experiments are used to develop constraints on models of earthquake recurrence. Constant-rate loading of bare rock surfaces in high quality experiments produces stick-slip recurrence that is periodic at least to second order. When the loading rate is varied, recurrence is approximately inversely proportional to loading rate. These laboratory events initiate due to a slip rate-dependent process that also determines the size of the stress drop [Dieterich, 1979; Ruina, 1983] and as a consequence, stress drop varies weakly but systematically with loading rate [e.g., Gu and Wong, 1991; Karner and Marone, 2000; McLaskey et al., 2012]. This is especially evident in experiments where the loading rate is changed by orders of magnitude, as is thought to be the loading condition of naturally occurring, small repeating earthquakes driven by afterslip, or low-frequency earthquakes loaded by episodic slip. As follows from the previous studies referred to above, experimentally observed stress drops are well described by a logarithmic dependence on recurrence interval that can be cast as a non-linear slip-predictable model. The fault’s rate dependence of strength is the key physical parameter. Additionally, even at constant loading rate the most reproducible laboratory recurrence is not exactly periodic, unlike existing friction recurrence models. We present example laboratory catalogs that document the variance and show that in large catalogs, even at constant loading rate, stress drop and recurrence co-vary systematically. The origin of this covariance is largely consistent with variability of the dependence of fault strength on slip rate. Laboratory catalogs show aspects of both slip and time predictability and successive stress drops are strongly correlated indicating a ‘memory’ of prior slip history that extends over at least one recurrence cycle.

De-labelling self-reported penicillin allergy within the emergency department through the use of skin tests and oral drug provocation testing.

PubMed

Marwood, Joseph; Aguirrebarrena, Gonzalo; Kerr, Stephen; Welch, Susan A; Rimmer, Janet

2017-10-01

Self-reported penicillin allergy is common among patients attending the ED, but is a poor predictor of true immunoglobulin E-mediated hypersensitivity to penicillin. We hypothesise that with a combination of skin testing and drug provocation testing, selected patients can be safely de-labelled of their allergy. This prospective study enrolled a sample of patients presenting to an urban academic ED between 2011 and 2016 with a self-reported allergy to penicillin. Standardised skin prick and intradermal testing with amoxicillin and both major and minor determinants of penicillin was performed in the department. If negative, testing was followed by a graded oral challenge of amoxicillin over 9 days. The primary end point was the allergy status of participants at the end of the study. A total of 100 patients (mean age 42; standard deviation 14 years; 54% women) completed the testing. Of these, 81% (95% confidence interval 71.9-88.2) showed no hypersensitivity to penicillin and were labelled non-allergic. The majority (16/19) of allergies were confirmed by skin testing, with three suspected allergies detected by the oral challenge. Women were more likely than men to have a true penicillin allergy, with odds ratio of 4.0 (95% confidence interval 1.23-13.2). There were no serious adverse events. Selected patients in the ED who self-report an allergy to penicillin can be safely tested there for penicillin allergy, using skin tests and oral drug provocation testing. This testing allows a significant de-labelling of penicillin allergy, with the majority of these patients able to tolerate penicillin without incident. © 2017 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

Comparison of pressure-controlled provocation discography using automated versus manual syringe pump manometry in patients with chronic low back pain.

PubMed

Derby, Richard; Lee, Sang Hoon; Lee, Jeong-Eun; Lee, Sang-Heon

2011-01-01

The study compares the rate of positive discograms using an automated versus a manual pressure-controlled injection devise and compares the pressure and volume values at various pressures and initial evoked pain and 6/10 or greater evoked pain. A retrospective study prospectively collected patient study data used in a prior prospective study and with prospectively collected data which is routinely collected per our institutional standardized audit protocol. Two custom-built disc manometers (automated injection speed control; manual injection speed control) were sequentially employed during provocation discography in 510 discs of 151 consecutive patients. Two hundred thirty-seven discs of 67 patients with chronic low back pain were evaluated using the automated manometer (automated group) and 273 discs of 84 patients were evaluated with a manual manometer (manual group). No significant differences in positive discogram rates were found between the automated and manual groups (32.1% vs 32.6% per disc, respectively, P>0.05). No significant differences in low-pressure positive discogram rates were found (16.0% vs 15.0% per disc, automated group versus manual group, respectively, P>0.05). However, there were significantly increased volumes and lower pressures at initial and "bad" pain provocation. The study results found equivalent positive discogram rates following a series of pressure-controlled discography using either an automated or manual pressure devise. There were, however significant increases in volume at both initial onset of evoked pain and at 6/10 pain when using the automated injection devise that may have caused the observed lower opening pressure and lower pressure values at initial evoked pain. Assuming increased volumes are innocuous, automated injection is inherently more controlled and may better reduce unintended and often unrecorded spurious high dynamic pressure peaks thereby reducing conscious and unconscious operator bias. Wiley Periodicals, Inc.

Ruminal changes in monensin- and lasalocid-fed cattle grazing bloat-provocative alfalfa pasture.

PubMed

Katz, M P; Nagaraja, T G; Fina, L R

1986-10-01

Microbial and fermentation changes in the rumen in monensin- and lasalocid-fed cattle grazing bloat-provocative alfalfa pasture were studied using genetically bloat-susceptible, ruminally-cannulated adult cattle. Monensin at .66 and .99 mg/kg body weight daily reduced the severity of legume bloat by 41 and 73%, respectively. The same doses of lasalocid reduced bloat by 25 and 12%. Comparison of ruminal contents from animals before treatment with ruminal contents from antibiotic-treated animals showed no differences in pH, ammonia, soluble N, soluble carbohydrate, ethanol-precipitable slime and anaerobic bacterial counts. Monensin treatment decreased protozoal numbers and microbial activity, as evidenced by lower gas production from in vitro fermentation of ground alfalfa hay when compared to pretreatment. Lasalocid had no effect on protozoal counts and in vitro gas production. Addition of monensin or lasalocid (12 micrograms/ml) to in vitro fermentation of chopped, fresh alfalfa reduced microbial activity as evidenced by higher soluble N, lower ammonia concentration and decreased gas production. Monensin reduced the amount of ethanol-precipitable slime and protozoal numbers. Reduction in the severity of bloat when monensin was fed appears to be due to decreased protozoal numbers, which resulted in decreased gas production. Lasalocid did not reduce legume bloat because of its minimal effect on the ruminal protozoa.

Fear Processing in Dental Phobia during Crossmodal Symptom Provocation: An fMRI Study

PubMed Central

Maslowski, Nina Isabel; Wittchen, Hans-Ulrich; Lueken, Ulrike

2014-01-01

While previous studies successfully identified the core neural substrates of the animal subtype of specific phobia, only few and inconsistent research is available for dental phobia. These findings might partly relate to the fact that, typically, visual stimuli were employed. The current study aimed to investigate the influence of stimulus modality on neural fear processing in dental phobia. Thirteen dental phobics (DP) and thirteen healthy controls (HC) attended a block-design functional magnetic resonance imaging (fMRI) symptom provocation paradigm encompassing both visual and auditory stimuli. Drill sounds and matched neutral sinus tones served as auditory stimuli and dentist scenes and matched neutral videos as visual stimuli. Group comparisons showed increased activation in the insula, anterior cingulate cortex, orbitofrontal cortex, and thalamus in DP compared to HC during auditory but not visual stimulation. On the contrary, no differential autonomic reactions were observed in DP. Present results are largely comparable to brain areas identified in animal phobia, but also point towards a potential downregulation of autonomic outflow by neural fear circuits in this disorder. Findings enlarge our knowledge about neural correlates of dental phobia and may help to understand the neural underpinnings of the clinical and physiological characteristics of the disorder. PMID:24738049

Burner Rig in the Material and Stresses Building

NASA Image and Video Library

1969-11-21

A burner rig heats up a material sample in the Materials and Stresses Building at the National Aeronautics and Space Administration (NASA) Lewis Research Center. Materials technology is an important element in the successful development of advanced airbreathing and rocket propulsion systems. Different types of engines operate in different environments so an array of dependable materials is needed. NASA Lewis began investigating the characteristics of different materials shortly after World War II. In 1949 the materials group was expanded into its own division. The Lewis researchers sought to study and test materials in environments that simulate the environment in which they would operate. The Materials and Stresses Building, built in 1949, contained a number of laboratories to analyze the materials. They are subjected to high temperatures, high stresses, corrosion, irradiation, and hot gasses. The Physics of Solids Laboratory included a cyclotron, cloud chamber, helium cryostat, and metallurgy cave. The Metallographic Laboratory possessed six x-ray diffraction machines, two metalloscopes, and other equipment. The Furnace Room had two large induction machines, a 4500⁰ F graphite furnace, and heat treating equipment. The Powder Laboratory included 60-ton and 3000-ton presses. The Stresses Laboratory included stress rupture machines, fatigue machines, and tensile strength machines.

Laboratory Workhorse: The Analytical Balance.

ERIC Educational Resources Information Center

Clark, Douglas W.

1979-01-01

This report explains the importance of various analytical balances in the water or wastewater laboratory. Stressed is the proper procedure for utilizing the equipment as well as the mechanics involved in its operation. (CS)

Stress drop with constant, scale independent seismic efficiency and overshoot

USGS Publications Warehouse

Beeler, N.M.

2001-01-01

To model dissipated and radiated energy during earthquake stress drop, I calculate dynamic fault slip using a single degree of freedom spring-slider block and a laboratory-based static/kinetic fault strength relation with a dynamic stress drop proportional to effective normal stress. The model is scaled to earthquake size assuming a circular rupture; stiffness varies inversely with rupture radius, and rupture duration is proportional to radius. Calculated seismic efficiency, the ratio of radiated to total energy expended during stress drop, is in good agreement with laboratory and field observations. Predicted overshoot, a measure of how much the static stress drop exceeds the dynamic stress drop, is higher than previously published laboratory and seismic observations and fully elasto-dynamic calculations. Seismic efficiency and overshoot are constant, independent of normal stress and scale. Calculated variation of apparent stress with seismic moment resembles the observational constraints of McGarr [1999].

An outsider's perspective on a provocative proposal: what would Flexner think?

PubMed

Anderson, M Brownell

2010-01-01

This viewpoint commentary focuses on a proposal for integrated anatomy education in undergraduate college from Dr. Darda published in the Anatomical Sciences Education. Although the proposal is for college level education, the proposal echoes some ideas proposed a century ago by Abraham Flexner when he wrote his report titled "Medical Education in the United States and Canada." It begins with an acknowledgement of the author's status as an outsider. There have been numerous calls for change in basic science education, particularly in medical education. Interestingly, however, the monumental reforms of the "Flexner Report" were impelled largely from outside the specific discipline of medical education. The commentary discussion then moves to observations about the proposal for Integrative Anatomy and support for the proposal from both the Flexner Report and the 2009 report from the Association of American Medical Colleges and the Howard Hughes Medical Institute, "Scientific Foundations for Future Physicians." The essay considers the benefits of the research on the learning sciences that now inform our work in education; the influence of competency-based education that frees education from a lock-step approach of course completion to a student-focused integrative approach to learning; and the availability of online resources for anatomy education through repositories, such as MedEdPORTAL. The final observation is that the changes underway in education and in the sciences basic to medicine, in particular, are substantial and will require the dialogue that Dr. Darda is promoting with his provocative proposal. Copyright 2010 American Association of Anatomists.

Effect of individually tailored biopsychosocial workplace interventions on chronic musculoskeletal pain, stress and work ability among laboratory technicians: randomized controlled trial protocol.

PubMed

Jay, Kenneth; Brandt, Mikkel; Sundstrup, Emil; Schraefel, Mc; Jakobsen, Markus D; Sjøgaard, Gisela; Andersen, Lars L

2014-12-18

Among laboratory technicians, the prevalence of neck and shoulder pain is widespread possibly due to typical daily work tasks such as pipetting, preparing vial samples for analysis, and data processing on a computer including mouse work - all tasks that require precision in motor control and may result in extended periods of time spent in static positions.In populations characterized by intense chronic musculoskeletal pain and diagnosed conditions in conjunction with psycho-physiological symptoms such as stress-related pain and soreness and other disabling conditions, multifactorial approaches applying a combination of individually tailored physical and cognitive strategies targeting the areas most needed, may be an effective solution to the physical and mental health challenges.The aim of this study is therefore to investigate the effect of an individually tailored biopsychosocial intervention strategy on musculoskeletal pain, stress and work disability in lab technicians with a history of musculoskeletal pain at a single worksite in Denmark. In this single-blind two-armed parallel-group randomized controlled trial with allocation concealment, participants receive either an individualized multifactorial intervention or "usual care" for 10 weeks at the worksite. 1) female laboratory technician (18-67 years of age) and 2) Pain intensity ≥ 3 (0-10 Visual Analogue Scale) lasting ≥3 months with a frequency of ≥ 3 days per week in one or more of the following regions: i) upper back i) low back iii) neck, iv) shoulder, v) elbow and/or vi) hand. 1) life-threatening disease and 2) pregnancy. Stress, as measured by Cohen´s perceived stress questionnaire is not an inclusion criteria, thus participants can participate regardless of their stress level.We will implement an individualized intervention addressing biopsychosocial elements of musculoskeletal pain with the following components; i) increasing physical capacity through strength- and motor control

Anger, impulsivity, and anger control in combat-related posttraumatic stress disorder.

PubMed

Chemtob, C M; Hamada, R S; Roitblat, H L; Muraoka, M Y

1994-08-01

Empirical evidence of a relationship between combat-related PTSD and increased anger is lacking. In this study, 24 veterans of the Vietnam War with posttraumatic stress disorder (PTSD) scored significantly higher on an Anger factor comprising multiple measures of anger than did comparison groups of 23 well-adjusted Vietnam combat veterans and 12 noncombat Vietnam-era veterans with psychiatric diagnoses. In contrast, the 3 groups did not differ significantly on orthogonal factors, one of which comprised cognitive impulsivity measures and the other of which reflected motor impulsivity. Changes in heart rate in response to provocation loaded positively on the Anger factor and negatively on the 2 Impulsivity factors. Concurrent depression and trait anxiety did not have an effect on level of anger in individuals with PTSD. These empirical findings support and extend the clinical evidence regarding PTSD and anger.

Toward Developing Laboratory-Based Parent-Adolescent Conflict Discussion Tasks that Consistently Elicit Adolescent Conflict-Related Stress Responses: Support from Physiology and Observed Behavior.

PubMed

Thomas, Sarah A; Wilson, Tristan; Jain, Anjali; Deros, Danielle E; Um, Miji; Hurwitz, Joanna; Jacobs, Irene; Myerberg, Lindsay; Ehrlich, Katherine B; Dunn, Emily J; Aldao, Amelia; Stadnik, Ryan; De Los Reyes, Andres

2017-12-01

Parent-adolescent conflict poses risk for youth maladjustment. One potential mechanism of this risk is that stress in the form of increased arousal during conflict interactions results in adolescents' impaired decision-making. However, eliciting consistent adolescent stress responses within laboratory-based tasks of parent-adolescent conflict (i.e., conflict discussion tasks) is hindered by task design. This limitation may stem from how conflict topics are assessed and selected for discussion. Within a sample of 47 adolescents (ages 14-17) and parents, we investigated whether a modified version of a conflict discussion task could elicit physiological (i.e., arousal) and behavioral (i.e., hostility) displays of adolescents' conflict-related stress responses. We assessed parent-adolescent conflict via structured interview to identify topics for dyads to discuss during the task. We randomly assigned dyads to complete a 5-minute task to discuss either a putatively benign topic (i.e., control condition) or a conflict topic while undergoing direct assessments of continuous arousal. Trained raters coded dyad members' hostile behavior during the task. Adolescents in the conflict condition exhibited significantly greater levels of arousal than adolescents in the control condition. We observed an interaction between discussion condition and baseline conflict. Specifically, higher baseline conflict predicted greater hostile behavior for adolescents in the conflict condition, yet we observed the inverse relation for adolescents in the control condition. Our modified laboratory discussion task successfully elicited both physiological and behavioral displays of adolescent conflict-related stress. These findings have important implications for leveraging experimental paradigms to understand causal links between parent-adolescent conflict and adolescent psychopathology, and their underlying mechanisms.

Impact decapitation from laboratory to basin scales

NASA Technical Reports Server (NTRS)

Schultz, P. H.; Gault, D. E.

1991-01-01

Although vertical hypervelocity impacts result in the annihilation (melting/vaporization) of the projectile, oblique impacts (less than 15 deg) fundamentally change the partitioning of energy with fragments as large as 10 percent of the original projectile surviving. Laboratory experiments reveal that both ductile and brittle projectiles produce very similar results where limiting disruption depends on stresses proportional to the vertical velocity component. Failure of the projectile at laboratory impact velocities (6 km/s) is largely controlled by stresses established before the projectile has penetrated a significant distance into the target. The planetary surface record exhibits numerous examples of oblique impacts with evidence fir projectile failure and downrange sibling collisions.

Do TETRA (Airwave) base station signals have a short-term impact on health and well-being? A randomized double-blind provocation study.

PubMed

Wallace, Denise; Eltiti, Stacy; Ridgewell, Anna; Garner, Kelly; Russo, Riccardo; Sepulveda, Francisco; Walker, Stuart; Quinlan, Terence; Dudley, Sandra; Maung, Sithu; Deeble, Roger; Fox, Elaine

2010-06-01

"Airwave" is the new communication system currently being rolled out across the United Kingdom for the police and emergency services, based on the Terrestrial Trunked Radio Telecommunications System (TETRA). Some police officers have complained about skin rashes, nausea, headaches, and depression as a consequence of using their Airwave handsets. In addition, a small subgroup in the population self-report being sensitive to electromagnetic fields (EMFs) in general. We conducted a randomized double-blind provocation study to establish whether short-term exposure to a TETRA base station signal has an impact on the health and well-being of individuals with self-reported "electrosensitivity" and of participants who served as controls. Fifty-one individuals with self-reported electrosensitivity and 132 age- and sex-matched controls participated in an open provocation test; 48 sensitive and 132 control participants went on to complete double-blind tests in a fully screened semianechoic chamber. Heart rate, skin conductance, and blood pressure readings provided objective indices of short-term physiological response. Visual analog scales and symptom scales provided subjective indices of well-being. We found no differences on any measure between TETRA and sham (no signal) under double-blind conditions for either controls or electrosensitive participants, and neither group could detect the presence of a TETRA signal at rates greater than chance (50%). When conditions were not double blind, however, the self-reported electrosensitive individuals did report feeling worse and experienced more severe symptoms during TETRA compared with sham. Our findings suggest that the adverse symptoms experienced by electrosensitive individuals are due to the belief of harm from TETRA base stations rather than to the low-level EMF exposure itself.

Human Handling Promotes Compliant Behavior in Adult Laboratory Rabbits

PubMed Central

Swennes, Alton G; Alworth, Leanne C; Harvey, Stephen B; Jones, Carolyn A; King, Christopher S; Crowell-Davis, Sharon L

2011-01-01

Routine laboratory procedures can be stressful for laboratory animals. We wanted to determine whether human handling of adult rabbits could induce a degree of habituation, reducing stress and facilitating research-related manipulation. To this end, adult New Zealand white rabbits were handled either frequently or minimally. After being handled over 3 wk, these rabbits were evaluated by novel personnel and compared with minimally handled controls. Evaluators subjectively scored the rabbits for their relative compliance or resistance to being scruffed and removed from their cages, being transported to a treatment room, and their behavior at all stages of the exercise. Upon evaluation, handled rabbits scored significantly more compliant than nontreated controls. During evaluation, behaviors that the rabbits displayed when they were approached in their cages and while being handled outside their cages were recorded and compared between study groups. Handled rabbits displayed behavior consistent with a reduction in human-directed fear. This study illustrates the potential for handling to improve compliance in laboratory procedures and reduce fear-related behavior in laboratory rabbits. Such handling could be used to improve rabbit welfare through the reduction of stress and exposure to novel stimuli. PMID:21333162

On relating apparent stress to the stress causing earthquake fault slip

USGS Publications Warehouse

McGarr, A.

1999-01-01

Apparent stress ??a is defined as ??a = ??????, where ???? is the average shear stress loading the fault plane to cause slip and ?? is the seismic efficiency, defined as Ea/W, where Ea is the energy radiated seismically and W is the total energy released by the earthquake. The results of a recent study in which apparent stresses of mining-induced earthquakes were compared to those measured for laboratory stick-slip friction events led to the hypothesis that ??a/???? ??? 0.06. This hypothesis is tested here against a substantially augmented data set of earthquakes for which ???? can be estimated, mostly from in situ stress measurements, for comparison with ??a. The expanded data set, which includes earthquakes artificially triggered at a depth of 9 km in the German Kontinentales Tiefbohrprogramm der Bundesrepublik Deutschland (KTB) borehole and natural tectonic earthquakes, covers a broad range of hypocentral depths, rock types, pore pressures, and tectonic settings. Nonetheless, over ???14 orders of magnitude in seismic moment, apparent stresses exhibit distinct upper bounds defined by a maximum seismic efficiency of ???0.06, consistent with the hypothesis proposed before. This behavior of ??a and ?? can be expressed in terms of two parameters measured for stick-slip friction events in the laboratory: the ratio of the static to the dynamic coefficient of friction and the fault slip overshoot. Typical values for these two parameters yield seismic efficiencies of ???0.06. In contrast to efficiencies for laboratory events for which ?? is always near 0.06, those for earthquakes tend to be less than this bounding value because Ea for earthquakes is usually underestimated due to factors such as band-limited recording. Thus upper bounds on ??a/???? appear to be controlled by just a few fundamental aspects of frictional stick-slip behavior that are common to shallow earthquakes everywhere. Estimates of ???? from measurements of ??a for suites of earthquakes, using ??a

Strain rate effects in stress corrosion cracking

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parkins, R.N.

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 maymore » 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.« less

Beat-to-Beat Variability of Ventricular Action Potential Duration Oscillates at Low Frequency During Sympathetic Provocation in Humans

PubMed Central

Porter, Bradley; van Duijvenboden, Stefan; Bishop, Martin J.; Orini, Michele; Claridge, Simon; Gould, Justin; Sieniewicz, Benjamin J.; Sidhu, Baldeep; Razavi, Reza; Rinaldi, Christopher A.; Gill, Jaswinder S.; Taggart, Peter

2018-01-01

Background: The temporal pattern of ventricular repolarization is of critical importance in arrhythmogenesis. Enhanced beat-to-beat variability (BBV) of ventricular action potential duration (APD) is pro-arrhythmic and is increased during sympathetic provocation. Since sympathetic nerve activity characteristically exhibits burst patterning in the low frequency range, we hypothesized that physiologically enhanced sympathetic activity may not only increase BBV of left ventricular APD but also impose a low frequency oscillation which further increases repolarization instability in humans. Methods and Results: Heart failure patients with cardiac resynchronization therapy defibrillator devices (n = 11) had activation recovery intervals (ARI, surrogate for APD) recorded from left ventricular epicardial electrodes alongside simultaneous non-invasive blood pressure and respiratory recordings. Fixed cycle length was achieved by right ventricular pacing. Recordings took place during resting conditions and following an autonomic stimulus (Valsalva). The variability of ARI and the normalized variability of ARI showed significant increases post Valsalva when compared to control (p = 0.019 and p = 0.032, respectively). The oscillatory behavior was quantified by spectral analysis. Significant increases in low frequency (LF) power (p = 0.002) and normalized LF power (p = 0.019) of ARI were seen following Valsalva. The Valsalva did not induce changes in conduction variability nor the LF oscillatory behavior of conduction. However, increases in the LF power of ARI were accompanied by increases in the LF power of systolic blood pressure (SBP) and the rate of systolic pressure increase (dP/dtmax). Positive correlations were found between LF-SBP and LF-dP/dtmax (rs = 0.933, p < 0.001), LF-ARI and LF-SBP (rs = 0.681, p = 0.001) and between LF-ARI and LF-dP/dtmax (rs = 0.623, p = 0.004). There was a strong positive correlation between the variability of ARI and LF power of ARI (rs = 0

Does spending time outdoors reduce stress? A review of real-time stress response to outdoor environments

Treesearch

Michelle C. Kondo; Sara F. Jacoby; Eugenia C. South

2018-01-01

Everyday environmental conditions impact human health. One mechanism underlying this relationship is the experience of stress. Through systematic review of published literature, we explore how stress has been measured in real-time non-laboratory studies of stress responses to deliberate exposure to outdoor environments. The types of exposures evaluated in this review...

Social Support and Networks: Cardiovascular Responses Following Recall on Immigration Stress Among Chinese Americans

PubMed Central

Suchday, Sonia; Wylie-Rosett, Judith

2014-01-01

Social support has been shown to act as a buffer for cardiovascular responses to stress. However, little is known about how social support and networks are related to cardiovascular responses to immigration stress recall. The current study evaluated the impact of structural and functional support on cardiovascular reaction following immigrant stress recall provocation as well as the moderation effect of interdependent self-construal among first-generation Chinese immigrants. One hundred fifty Chinese immigrants were recruited in the New York Chinatown area. Participants completed questionnaires assessing their levels of social support and networks, and interdependent self-construal. Following adaptation, participants recalled a recent post-immigration stress-provoking situation. Cardiovascular measures were taken during adaptation, stressor task, and recovery period. Hierarchical multiple regression analysis was performed. Social network size and type, as well as perceived emotional support were positively predictive of systolic blood pressure (SBP) reactivity changes. Instrumental support seeking was a positive predictor of SBP and diastolic blood pressure (DBP) reactivity. The moderation effect between instrumental support seeking and interdependent self-construal were significantly predictive of DBP reactivity and recovery, suggesting that perceptions about themselves in relation to others is a crucial factor for determining whether support seeking is beneficial or not. Social support was not a direct buffer on cardiovascular responses to stress among Chinese immigrants. Chinese values of interdependence and collectivism may partly explain the disconfirming results. Still, when interdependent self-construal was taken into account, Chinese immigrants who had less interdependent self-construal, but solicited more instrumental support, had faster adaptation to stress over the long term. PMID:24288021

THE ROLE OF MICROGLIA IN PARAQUAT INDUCED DOPAMINERGIC NEUROTOXICITY.

EPA Science Inventory

This manuscript relates oxidative stress conveyed by a widely used pesticide (paraquat) to selective neurodegeneration of the in vitro models of the mouse brain. As such, it represents a provocative link to the conditions of oxidative stress, environmental chemical exposures and...

Ethnic differences in cardiovascular responses to laboratory stress: a comparison between asian and white americans.

PubMed

Shen, Biing-Jiun; Stroud, Laura R; Niaura, Raymond

2004-01-01

Compared to other ethnic groups, Asian Americans show significantly lower rates of cardiovascular disease (CVD). We tested the hypothesis that Asian Americans would show reduced cardiovascular responses to laboratory stressors than Caucasians. Forty-three Asians (18 men, 25 women) and 77 Caucasians (36 men, 41 women) with a mean age of 24 years (SD = 3.93) participated in a stress reactivity protocol consisting of four tasks (speech, serial subtraction, mirror tracing, handgrip) while heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were measured. Asian Americans demonstrated overall lower reactivity across tasks for SBP F(1,117 = 7.48, p < .01) and a trend toward lower HR response F(1,117 = 3.18, p < .10). A significant ethnicity by task interaction was observed for HR reactivity F(3,351 = 2.94, p < .05) such that Caucasians showed greater responses for the subtraction task.

Evaluation of JNJ-54717793 a Novel Brain Penetrant Selective Orexin 1 Receptor Antagonist in Two Rat Models of Panic Attack Provocation.

PubMed

Bonaventure, Pascal; Dugovic, Christine; Shireman, Brock; Preville, Cathy; Yun, Sujin; Lord, Brian; Nepomuceno, Diane; Wennerholm, Michelle; Lovenberg, Timothy; Carruthers, Nicolas; Fitz, Stephanie D; Shekhar, Anantha; Johnson, Philip L

2017-01-01

Orexin neurons originating in the perifornical and lateral hypothalamic area are highly reactive to anxiogenic stimuli and have strong projections to anxiety and panic-associated circuitry. Recent studies support a role for the orexin system and in particular the orexin 1 receptor (OX1R) in coordinating an integrative stress response. However, no selective OX1R antagonist has been systematically tested in two preclinical models of using panicogenic stimuli that induce panic attack in the majority of people with panic disorder, namely an acute hypercapnia-panic provocation model and a model involving chronic inhibition of GABA synthesis in the perifornical hypothalamic area followed by intravenous sodium lactate infusion. Here we report on a novel brain penetrant, selective and high affinity OX1R antagonist JNJ-54717793 (1S,2R,4R)-7-([(3-fluoro-2-pyrimidin-2-ylphenyl)carbonyl]- N -[5-(trifluoromethyl)pyrazin-2-yl]-7-azabicyclo[2.2.1]heptan-2-amine). JNJ-54717793 is a high affinity/potent OX1R antagonist and has an excellent selectivity profile including 50 fold versus the OX2R. Ex vivo receptor binding studies demonstrated that after oral administration JNJ-54717793 crossed the blood brain barrier and occupied OX1Rs in the rat brain. While JNJ-54717793 had minimal effect on spontaneous sleep in rats and in wild-type mice, its administration in OX2R knockout mice, selectively promoted rapid eye movement sleep, demonstrating target engagement and specific OX1R blockade. JNJ-54717793 attenuated CO 2 and sodium lactate induced panic-like behaviors and cardiovascular responses without altering baseline locomotor or autonomic activity. These data confirm that selective OX1R antagonism may represent a novel approach of treating anxiety disorders, with no apparent sedative effects.

Evaluation of JNJ-54717793 a Novel Brain Penetrant Selective Orexin 1 Receptor Antagonist in Two Rat Models of Panic Attack Provocation

PubMed Central

Bonaventure, Pascal; Dugovic, Christine; Shireman, Brock; Preville, Cathy; Yun, Sujin; Lord, Brian; Nepomuceno, Diane; Wennerholm, Michelle; Lovenberg, Timothy; Carruthers, Nicolas; Fitz, Stephanie D.; Shekhar, Anantha; Johnson, Philip L.

2017-01-01

Orexin neurons originating in the perifornical and lateral hypothalamic area are highly reactive to anxiogenic stimuli and have strong projections to anxiety and panic-associated circuitry. Recent studies support a role for the orexin system and in particular the orexin 1 receptor (OX1R) in coordinating an integrative stress response. However, no selective OX1R antagonist has been systematically tested in two preclinical models of using panicogenic stimuli that induce panic attack in the majority of people with panic disorder, namely an acute hypercapnia-panic provocation model and a model involving chronic inhibition of GABA synthesis in the perifornical hypothalamic area followed by intravenous sodium lactate infusion. Here we report on a novel brain penetrant, selective and high affinity OX1R antagonist JNJ-54717793 (1S,2R,4R)-7-([(3-fluoro-2-pyrimidin-2-ylphenyl)carbonyl]-N-[5-(trifluoromethyl)pyrazin-2-yl]-7-azabicyclo[2.2.1]heptan-2-amine). JNJ-54717793 is a high affinity/potent OX1R antagonist and has an excellent selectivity profile including 50 fold versus the OX2R. Ex vivo receptor binding studies demonstrated that after oral administration JNJ-54717793 crossed the blood brain barrier and occupied OX1Rs in the rat brain. While JNJ-54717793 had minimal effect on spontaneous sleep in rats and in wild-type mice, its administration in OX2R knockout mice, selectively promoted rapid eye movement sleep, demonstrating target engagement and specific OX1R blockade. JNJ-54717793 attenuated CO2 and sodium lactate induced panic-like behaviors and cardiovascular responses without altering baseline locomotor or autonomic activity. These data confirm that selective OX1R antagonism may represent a novel approach of treating anxiety disorders, with no apparent sedative effects. PMID:28649201

Enhanced Stress Relaxation and Reduced Cure Stress in Thermosets with Ferrocene-Based Crosslinkers

NASA Astrophysics Data System (ADS)

Jones, Brad; Wheeler, David; Stavig, Mark; Black, Hayden; Sawyer, Patricia; Giron, Nicholas; Celina, Mathias; Alam, Todd

Organometallic sandwich compounds are characterized by facile isomerization among a variety of unique states. For example, ferrocene exhibits an extraordinarily low barrier to rotation of its cyclopentadienyl (Cp) ligands about the metal-Cp axis. We propose that this phenomenon can be exploited to enhance stress relaxation of polymers containing organometallic sandwich backbone moieties. Here, we describe the synthesis and characterization of several thermosets that employ ferrocene derivatives as crosslinkers. In particular, we compare a ferrocene diamine to several conventional diamines in the crosslinking of epoxy resin. Stress relaxation and dynamic mechanical analyses reveal that the ferrocene-based thermosets are distinguished from conventional thermosets by their capacity for physical relaxation. More importantly, these materials exhibit markedly different residual stress evolution during cure. For example, the cure stress in ferrocene-based thermosets drops precipitously with decreasing crosslink density. Our results highlight the unique role organometallic chemistry can play for stress management of thermosets and, more broadly, in manipulating their structure-property relationships. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company, for the US Department of Energy National Nuclear Security Administration under contract DE-AC04-94AL85000.

Do TETRA (Airwave) Base Station Signals Have a Short-Term Impact on Health and Well-Being? A Randomized Double-Blind Provocation Study

PubMed Central

Wallace, Denise; Eltiti, Stacy; Ridgewell, Anna; Garner, Kelly; Russo, Riccardo; Sepulveda, Francisco; Walker, Stuart; Quinlan, Terence; Dudley, Sandra; Maung, Sithu; Deeble, Roger; Fox, Elaine

2010-01-01

Background “Airwave” is the new communication system currently being rolled out across the United Kingdom for the police and emergency services, based on the Terrestrial Trunked Radio Telecommunications System (TETRA). Some police officers have complained about skin rashes, nausea, headaches, and depression as a consequence of using their Airwave handsets. In addition, a small subgroup in the population self-report being sensitive to electromagnetic fields (EMFs) in general. Objectives We conducted a randomized double-blind provocation study to establish whether short-term exposure to a TETRA base station signal has an impact on the health and well-being of individuals with self-reported “electrosensitivity” and of participants who served as controls. Methods Fifty-one individuals with self-reported electrosensitivity and 132 age- and sex-matched controls participated in an open provocation test; 48 sensitive and 132 control participants went on to complete double-blind tests in a fully screened semianechoic chamber. Heart rate, skin conductance, and blood pressure readings provided objective indices of short-term physiological response. Visual analog scales and symptom scales provided subjective indices of well-being. Results We found no differences on any measure between TETRA and sham (no signal) under double-blind conditions for either controls or electrosensitive participants, and neither group could detect the presence of a TETRA signal at rates greater than chance (50%). When conditions were not double blind, however, the self-reported electrosensitive individuals did report feeling worse and experienced more severe symptoms during TETRA compared with sham. Conclusions Our findings suggest that the adverse symptoms experienced by electrosensitive individuals are due to the belief of harm from TETRA base stations rather than to the low-level EMF exposure itself. PMID:20075020

Physiological Reactivity and Recent Life-Stress Experience.

ERIC Educational Resources Information Center

Pardine, Peter; Napoli, Anthony

1983-01-01

Assessed differences in cardiovascular reactivity between high and low life-stress students (N=26). Results indicated high life-stress individuals maintained their elevated stressor levels throughout recovery from a laboratory stressor, and showed significantly higher systolic recovery levels compared to the low stress group. (JAC)

Trait Hostility and Acute Inflammatory Responses to Stress in the Laboratory

PubMed Central

Girard, Dominique; Tardif, Jean-Claude; Boisclair Demarble, Julie; D’Antono, Bianca

2016-01-01

Hostility has been associated with higher basal levels of inflammation. The present study evaluated the association of hostility with acute stress-induced changes in inflammatory activity. One hundred and ninety-nine healthy men and women, aged 19–64 years, were exposed to a stress protocol involving four interpersonal stressors. Participants completed the Cook-Medley Hostility questionnaire and provided two blood samples for the measurement of inflammatory biomarkers (CRP, Il-6, MPO, TNF-α, MCP-1, Il-8, Il-10, and Il-18), prior to and following exposure to a standardized stress protocol. In univariate analyses, hostility was associated with significantly higher TNF-α, but lower Il-8 and Il-18 values post-stress, though only Il-8 remained significant after controlling for baseline differences. In multivariate analyses, a significant Age by Hostility interaction emerged for Il-6, while sex moderated the relation between hostility and Il-10 reactivity. Following stress, hostility was associated with greater pro-inflammatory Il-6 activity among younger individuals and to decreased anti-inflammatory Il-10 activity in women. Future research is needed to replicate these findings and to evaluate their implication for disease. PMID:27270459

Opioid Hypersensitivity: Predictors of Allergy and Role of Drug Provocation Testing.

PubMed

Li, Philip H; Ue, Kok Loong; Wagner, Annette; Rutkowski, Ryszard; Rutkowski, Krzysztof

True IgE-mediated hypersensitivity to opioids is rare and many reactions are due to direct mast cell degranulation. Opioid drug provocation testing (DPT) is the gold standard for diagnosis but is underutilized. The objective of this study was to evaluate the clinical characteristics and predictors of opioid hypersensitivity, as well as outcomes of opioid DPT. Patients referred for opioid DPT over the past 9 years were studied. Patient characteristics, indications for opioid use, symptoms of index reaction, and outcomes of DPT were analyzed. Association analysis was performed to study variables associated with a diagnosis of opioid hypersensitivity. Of the total of 98 patients referred with suspected opioid hypersensitivity, 15 (15%) were diagnosed with opioid allergy. Angioedema (odds ratio [OR]: 5.66; 95% confidence interval [CI]: 1.49-21.47; P = .011) and hypotension (OR: 5.00; 95% CI: 1.15-21.70; P = .032) were significantly more frequent in opioid allergic patients than those with a negative DPT. Patients who received opioids during anesthesia were significantly more likely to be opioid allergic (OR: 6.74; 95% CI: 2.05-22.13; P = .001). In contrast, a negative association was identified with patients who received opioids for analgesia (OR: 0.27; 95% CI: 0.08-0.86; P = .008). Only 15% of our cohort were diagnosed with opioid allergy, emphasizing the importance of DPT in preventing erroneous overdiagnosis. Patients with a history of angioedema or hypotension as their index reaction were significantly more likely to be opioid allergic. DPT are safe when performed by experienced clinicians after risk stratification and using individualized protocols. Copyright © 2017 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Meditation as an Intervention in Stress Reactivity

ERIC Educational Resources Information Center

Goleman, Daniel J.; Schwartz, Gary E.

1976-01-01

Meditation and relaxation were compared for ability to reduce stress reactions in a laboratory threat situation. Meditation can produce a psychophysiological configuration in stress situations opposite to that seen in stress-related syndromes. Research is indicated on clinical applications and on the process whereby meditation state effects may…

The Oral Provocation Test for Raw Egg in Patients with Hen Egg Allergy.

PubMed

Kido, Jun; Nishi, Natsuko; Matsumoto, Tomoaki

2018-06-06

Many researchers have made efforts to develop diagnostic tools for predicting the outcome of oral food challenges (OFCs). The aim of this study was to assess the diagnostic value of the skin prick test (SPT) and blood-specific IgE concentrations based on the outcome of the OFCs for heated and raw hen egg. This study included 103 children with suspected hen egg allergy (HEA; median age 23 months, range 10-155; 72 boys, 31 girls). Forty-three patients were diagnosed with HEA by OFC. Of 60 patients who tolerated heated egg white (HEW), 22 underwent the OFC for raw hen egg and 7 developed adverse reactions after ingesting raw egg. Their wheal diameters and specific IgE levels for egg white and ovomucoid were determined. Wheal diameters as well as blood-specific IgE levels for egg white and ovomucoid were significantly larger in children with positive OFC results for HEW than in those with negative results. However, there were no significant differences between the positive and negative test results for raw hen egg white (REW) in wheal diameter or blood-specific IgE levels. The SPT and blood-specific IgE can be used to diagnose HEA. However, the provocation test for REW in children without HEW allergy is important because the values of SPT and specific IgE were not significantly different between children with and without raw egg allergy. © 2018 S. Karger AG, Basel.

Performance of stress-laminated timber highway bridges in cold climates

Treesearch

James P. Wacker

2009-01-01

This paper summarizes recent laboratory and field data studies on thermal performance of stress-laminated timber highway bridges. Concerns about the reliability of stress-laminated deck bridges when exposed to sub-freezing temperatures triggered several investigations. Two laboratory studies were conducted to study the effects of wood species, preservative, moisture...

Site Description for the University of Nebraska's Sandhills Agricultural Laboratory

NASA Technical Reports Server (NTRS)

Gardner, B. R.; Blad, B. L.

1985-01-01

The Sandhills Agricultural Laboratory is operated by the University of Nebraska. The laboratory is located in the south-central part of the Nebraska Sandhills near Tryon, Nebraska (41 deg. 37' N; 100 deg. 50' W). The laboratory is surrounded on the west and south by native rangeland vegetation, on the south by a large field of corn irrigated by a center pivot, and on the east by wheat stubble. This site is appropriate for moisture stress studies since rainfall is almost always inadequate to meet evaporative demands of agricultural crops during most of the growing season and the sandy soils (Valentine fine sand) at the site do not store large quantities of water. Various levels of water stress are achieved through irrigation from solid set sprinklers.

Some comparisons between mining-induced and laboratory earthquakes

USGS Publications Warehouse

McGarr, A.

1994-01-01

Although laboratory stick-slip friction experiments have long been regarded as analogs to natural crustal earthquakes, the potential use of laboratory results for understanding the earthquake source mechanism has not been fully exploited because of essential difficulties in relating seismographic data to measurements made in the controlled laboratory environment. Mining-induced earthquakes, however, provide a means of calibrating the seismic data in terms of laboratory results because, in contrast to natural earthquakes, the causative forces as well as the hypocentral conditions are known. A comparison of stick-slip friction events in a large granite sample with mining-induced earthquakes in South Africa and Canada indicates both similarities and differences between the two phenomena. The physics of unstable fault slip appears to be largely the same for both types of events. For example, both laboratory and mining-induced earthquakes have very low seismic efficiencies {Mathematical expression} where ??a is the apparent stress and {Mathematical expression} is the average stress acting on the fault plane to cause slip; nearly all of the energy released by faulting is consumed in overcoming friction. In more detail, the mining-induced earthquakes differ from the laboratory events in the behavior of ?? as a function of seismic moment M0. Whereas for the laboratory events ?????0.06 independent of M0, ?? depends quite strongly on M0 for each set of induced earthquakes, with 0.06 serving, apparently, as an upper bound. It seems most likely that this observed scaling difference is due to variations in slip distribution over the fault plane. In the laboratory, a stick-slip event entails homogeneous slip over a fault of fixed area. For each set of induced earthquakes, the fault area appears to be approximately fixed but the slip is inhomogeneous due presumably to barriers (zones of no slip) distributed over the fault plane; at constant {Mathematical expression}, larger

Evaluation of Cobas Integra 800 under simulated routine conditions in six laboratories.

PubMed

Redondo, Francisco L; Bermudez, Pilar; Cocco, Claudio; Colella, Francesca; Graziani, Maria Stella; Fiehn, Walter; Hierla, Thomas; Lemoël, Gisèle; Belliard, AnneMarie; Manene, Dieudonne; Meziani, Mourad; Liebel, Maryann; McQueen, Matthew J; Stockmann, Wolfgang

2003-03-01

The new selective access analyser Cobas Integra 800 from Roche Diagnostics was evaluated in an international multicentre study at six sites. Routine simulation experiments showed good performance and full functionality of the instrument and provocation of anomalous situations generated no problems. The new features on Cobas Integra 800, namely clot detection and dispensing control, worked according to specifications. The imprecision of Cobas Integra 800 fulfilled the proposed quality specifications regarding imprecision of analytical systems for clinical chemistry with few exceptions. Claims for linearity, drift, and carry-over were all within the defined specifications, except urea linearity. Interference exists in some cases, as could be expected due to the chemistries applied. Accuracy met the proposed quality specifications, except in some special cases. Method comparisons with Cobas Integra 700 showed good agreement; comparisons with other analysis systems yielded in several cases explicable deviations. Practicability of Cobas Integra 800 met or exceeded the requirements for more than 95% of all attributes rated. The strong points of the new analysis system were reagent handling, long stability of calibration curves, high number of tests on board, compatibility of the sample carrier to other Roche systems, and the sample integrity check for more reliable analytical results. The improvement of the workflow offered by the 5-position rack and STAT handling like on Cobas Integra 800 makes the instrument attractive for further consolidation in the medium-sized laboratory, for dedicated use of special analytes, and/or as back-up in the large routine laboratory.

Validation of the Novaco Anger Scale-Provocation Inventory (Danish) With Nonclinical, Clinical, and Offender Samples.

PubMed

Moeller, Stine Bjerrum; Novaco, Raymond W; Heinola-Nielsen, Vivian; Hougaard, Helle

2016-10-01

Anger has high prevalence in clinical and forensic settings, and it is associated with aggressive behavior and ward atmosphere on psychiatric units. Dysregulated anger is a clinical problem in Danish mental health care systems, but no anger assessment instruments have been validated in Danish. Because the Novaco Anger Scale and Provocation Inventory (NAS-PI) has been extensively validated with different clinical populations and lends itself to clinical case formulation, it was selected for translation and evaluation in the present multistudy project. Psychometric properties of the NAS-PI were investigated with samples of 477 nonclinical, 250 clinical, 167 male prisoner, and 64 male forensic participants. Anger prevalence and its relationship with other anger measures, anxiety/depression, and aggression were examined. NAS-PI was found to have high reliability, concurrent validity, and discriminant validity, and its scores discriminated the samples. High scores in the offender group demonstrated the feasibility of obtaining self-report assessments of anger with this population. Retrospective and prospective validity of the NAS were tested with the forensic patient sample regarding physically aggressive behavior in hospital. Regression analyses showed that higher scores on NAS increase the risk of having acted aggressively in the past and of acting aggressively in the future. © The Author(s) 2015.

Cortisol reactivity to stress among youth: Stability over time and genetic variants for stress sensitivity

PubMed Central

Hankin, Benjamin L.; Badanes, Lisa S.; Smolen, Andrew; Young, Jami F.

2015-01-01

Stress sensitivity may be one process that can explain why some genetically at-risk individuals are more susceptible to some types of stress-reactive psychopathologies. Dysregulation of the Limbic Hypothalamic Pituitary Adrenal (LHPA) axis, including cortisol reactivity to challenge, represents a key aspect of stress sensitivity. However, the degree of stability over time among youth, especially differential stability as a function of particular genetic variants, has not been investigated. A general community sample of children and adolescents (mean age = 11.4; 56% girls) provided a DNA sample and completed two separate laboratory stress challenges, across an 18-month follow-up (N =224 at Time 1; N = 194 at Time 2), with repeated measures of salivary cortisol. Results showed that test-retest stability for several indices of cortisol reactivity across the laboratory challenge visits were significant and of moderate magnitude for the whole sample. Moreover, gene variants of several biologically plausible systems relevant for stress sensitivity (especially 5-HTTLPR and CRHR1) demonstrated differential stability of cortisol reactivity over 18-months, such that carriers of genotypes conferring enhanced environmental susceptibility exhibited greater stability of cortisol levels over time for some LHPA axis indices. Findings suggest that LHPA axis dysregulation may exhibit some trait-like aspects underlying stress sensitivity in youth, especially for those who carry genes related to greater genetic susceptibility to environmental stress. PMID:25688432

Provocative questions in parochial sex education classes: higher incidence in younger students.

PubMed

Moreno, Megan; Breuner, Cora C; Lozano, Paula

2008-10-01

Recent data show US adolescents are engaging in sexual activity at earlier ages; however, little is known about young teens' sexual attitudes and behaviors. Examining teens' questions in sex education classes may provide insight into these attitudes and behaviors. Quasi cohort study Parochial middle school sex education classes 5(th) through 8(th) graders Students' anonymous written questions submitted at the outset of sex education classes between 2003 and 2005. Questions were classified into topic categories. Three additional variables were then coded for each question. Ethics/guidance questions included requests for advice or value judgments. Prohibited questions included the topics homosexuality, abortion, masturbation, and contraception. "Red flag" questions were those that suggested consideration of or engagement in sexual behavior. Among 473 questions submitted by 410 students, the most popular topics for 5(th)/6(th) graders were pregnancy and puberty, and for 7(th)/8(th) graders puberty and menstruation. 41 questions (8.6%) were prohibited. 29 questions (6.2%) asked about ethics/guidance. 18 questions (3.81%) were coded as red flag questions. A chi-square analysis showed that 5(th)/6(th) graders asked more questions in the ethics/guidance (8.3% versus 3.64%) and red flag question categories (5.53% versus 1.82%) (P < 0.05) than 7(th)/8(th) graders. Although provocative questions represent a minority of these middle students' queries, these requests suggest the urgency of providing appropriate guidance to young teens, given the risks of early sexual activity. The role of school education programs, physicians and parents in addressing questions of this sort should be considered.

Effects of social isolation and environmental enrichment on laboratory housed pigs

USDA-ARS?s Scientific Manuscript database

The pig is becoming an increasingly important laboratory animal species. However, a laboratory setting often requires individual and sterile housing, which may impose stress. The objective of this study was to determine physiological, haematological and behavioral effects of isolation and environmen...

High basal metabolic rate does not elevate oxidative stress during reproduction in laboratory mice.

PubMed

Brzęk, Paweł; Książek, Aneta; Ołdakowski, Łukasz; Konarzewski, Marek

2014-05-01

Increased oxidative stress (OS) has been suggested as a physiological cost of reproduction. However, previous studies reported ambiguous results, with some even showing a reduction of oxidative damage during reproduction. We tested whether the link between reproduction and OS is mediated by basal metabolic rate (BMR), which has been hypothesized to affect both the rate of radical oxygen species production and antioxidative capacity. We studied the effect of reproduction on OS in females of laboratory mice divergently selected for high (H-BMR) and low (L-BMR) BMR, previously shown to differ with respect to parental investment. Non-reproducing L-BMR females showed higher oxidative damage to lipids (quantified as the level of malondialdehyde in internal organ tissues) and DNA (quantified as the level of 8-oxodG in blood serum) than H-BMR females. Reproduction did not affect oxidative damage to lipids in either line; however, it reduced damage to DNA in L-BMR females. Reproduction increased catalase activity in liver (significantly stronger in L-BMR females) and decreased it in kidneys. We conclude that the effect of reproduction on OS depends on the initial variation in BMR and varies between studied internal organs and markers of OS.

Trauma- and Stress-Induced Response in Veterans with Alcohol Dependence and Comorbid Post-Traumatic Stress Disorder.

PubMed

Ralevski, Elizabeth; Southwick, Steven; Jackson, Eric; Jane, Jane Serrita; Russo, Melanie; Petrakis, Ismene

2016-08-01

Alcohol dependence (AD) and post-traumatic stress disorder (PTSD) commonly co-occur, and the co-occurrence is associated with worse prognosis than either disorder absent the other. Craving is an important construct related to relapse, but the relationship between PTSD symptoms, craving, and relapse is not well understood. Several studies have documented the relationship between stress and craving in individuals without comorbid PTSD, but the effect on those with comorbid PTSD is not well known. A small literature suggests that trauma imagery affects craving. This is the first study to explore the effects of trauma-induced and stress-induced scripts on alcohol craving, affect, cardiovascular, and cortisol responses in the laboratory. Veterans (n = 25) diagnosed with AD and PTSD who were participating in a randomized clinical treatment trial took part in this laboratory study. Baseline assessment included PTSD symptoms and drinking quantity and frequency over 3 months before study initiation. In the laboratory, participants were exposed to neutral, stressful, and trauma scripts randomly assigned. Main outcomes included craving, anxiety, mood states, salivary cortisol, and cardiovascular responses. Both stress and trauma scripts produced greater increases in craving, negative affect, and cardiovascular reactivity, compared to neutral scripts. Trauma scripts produced significantly stronger craving for alcohol and greater cardiovascular reactivity than stress scripts. Also, trauma-induced but not stress-induced craving was positively correlated with baseline levels of drinking. There were no changes in cortisol levels from pre- to postexposure of any scripts. The results highlight that trauma cues are more salient in inducing alcohol craving than stress cues and higher reactivity is related to more baseline drinking. This finding is consistent with clinical observations that show an association between PTSD symptoms and alcohol relapse. It also underscores the

Correlation of predicted and measured thermal stresses on an advanced aircraft structure with similar materials

NASA Technical Reports Server (NTRS)

Jenkins, J. M.

1979-01-01

A laboratory heating test simulating hypersonic heating was conducted on a heat-sink type structure to provide basic thermal stress measurements. Six NASTRAN models utilizing various combinations of bar, shear panel, membrane, and plate elements were used to develop calculated thermal stresses. Thermal stresses were also calculated using a beam model. For a given temperature distribution there was very little variation in NASTRAN calculated thermal stresses when element types were interchanged for a given grid system. Thermal stresses calculated for the beam model compared similarly to the values obtained for the NASTRAN models. Calculated thermal stresses compared generally well to laboratory measured thermal stresses. A discrepancy of signifiance occurred between the measured and predicted thermal stresses in the skin areas. A minor anomaly in the laboratory skin heating uniformity resulted in inadequate temperature input data for the structural models.

The diagnostic value of finger systolic blood pressure and cold-provocation testing for the vascular component of hand-arm vibration syndrome in health surveillance.

PubMed

Poole, K; Elms, J; Mason, H J

2004-12-01

Hand-arm vibration syndrome (HAVS) is a complex condition with vascular, sensorineural and musculoskeletal components. A number of quantitative tests have been used for assisting in the diagnosis of HAVS and grading disease severity. To investigate and compare the diagnostic value of finger systolic blood pressure (FSBP) and rewarming of finger skin temperature (FST) following cold-provocation testing, in the assessment of vascular HAVS. Twenty-four individuals with vascular HAVS (Stockholm Workshop stage 2 or 3V) and 22 control subjects underwent FSBP measurements at 30, 15 and 10 degrees C and monitoring of FST following immersion of the hands in water at 15 degrees C for 5 min. There was a significant reduction in median FSBP% in the vascular HAVS group in the change in FSBP from 30 to 15 degrees C adjusted for brachial blood pressure (FSBPC%). There was no difference in the median time for FST to rewarm by 4 degrees C between HAVS cases and controls. The sensitivity and specificity of FSBP to discriminate between the groups varied between 44 and 61% and 91 and 95%, respectively. The sensitivity and specificity for the time for FST to rewarm by 4 degrees C were 71 and 77%. There is little evidence that the described form of finger rewarming after cold-provocation testing is a useful diagnostic test for vascular HAVS, although it may have some moderate influence in ruling out vascular problems. Based on our data, the FSBP may also have limited use in confirming a positive diagnosis of vibration-induced vascular problems. The higher specificity of the FSBP test suggests it may have some value in ruling out the vascular component of HAVS. The data from this study do not confirm the diagnostic power of FSBP for the vascular component of HAVS reported by a few other investigators.

Near-fault peak ground velocity from earthquake and laboratory data

USGS Publications Warehouse

McGarr, A.; Fletcher, Joe B.

2007-01-01

We test the hypothesis that peak ground velocity (PGV) has an upper bound independent of earthquake magnitude and that this bound is controlled primarily by the strength of the seismogenic crust. The highest PGVs, ranging up to several meters per second, have been measured at sites within a few kilometers of the causative faults. Because the database for near-fault PGV is small, we use earthquake slip models, laboratory experiments, and evidence from a mining-induced earthquake to investigate the factors influencing near-fault PGV and the nature of its scaling. For each earthquake slip model we have calculated the peak slip rates for all subfaults and then chosen the maximum of these rates as an estimate of twice the largest near-fault PGV. Nine slip models for eight earthquakes, with magnitudes ranging from 6.5 to 7.6, yielded maximum peak slip rates ranging from 2.3 to 12 m/sec with a median of 5.9 m/sec. By making several adjustments, PGVs for small earthquakes can be simulated from peak slip rates measured during laboratory stick-slip experiments. First, we adjust the PGV for differences in the state of stress (i.e., the difference between the laboratory loading stresses and those appropriate for faults at seismogenic depths). To do this, we multiply both the slip and the peak slip rate by the ratio of the effective normal stresses acting on fault planes measured at 6.8 km depth at the KTB site, Germany (deepest available in situ stress measurements), to those acting on the laboratory faults. We also adjust the seismic moment by replacing the laboratory fault with a buried circular shear crack whose radius is chosen to match the experimental unloading stiffness. An additional, less important adjustment is needed for experiments run in triaxial loading conditions. With these adjustments, peak slip rates for 10 stick-slip events, with scaled moment magnitudes from -2.9 to 1.0, range from 3.3 to 10.3 m/sec, with a median of 5.4 m/sec. Both the earthquake and

Effective utilization of clinical laboratories.

PubMed

Murphy, J; Henry, J B

1978-11-01

Effective utilization of clinical laboratories requires that underutilization, overutilization, and malutilization be appreciated and eliminated or reduced. Optimal patient care service, although subjective to a major extent, is reflected in terms of outcome and cost. Increased per diem charges, reduced hospital stay, and increased laboratory workload over the past decade all require each laboratory to examine its internal operations to achieve economy and efficiency as well as maximal effectiveness. Increased research and development, an active managerial role on the part of pathologists, internal self-assessment, and an aggressive response to sophisticated scientific and clinical laboratory data base requirements are not only desirable but essential. The importance of undergraduate and graduate medical education in laboratory medicine to insure understanding as well as effective utilization is stressed. The costs and limitations as well as the accuracy, precision, sensitivity, specificity, and pitfalls of measurements and examinations must also be fully appreciated. Medical malpractice and defensive medicine and the use of critical values, emergency and routine services, and an active clinical role by the pathologist are of the utmost value in assuring effective utilization of the laboratory. A model for the optimal use of the laboratory including economy and efficiency has been achieved in the blood bank in regard to optimal hemotherapy for elective surgery, assuring superior patient care in a cost effective and safe manner.

Laboratory research of fracture geometry in multistage HFF in triaxial state

NASA Astrophysics Data System (ADS)

Bondarenko, T. M.; Hou, B.; Chen, M.; Yan, L.

2017-05-01

Multistage hydraulic fracturing of formation (HFF) in wells with horizontal completion is an efficientmethod for intensifying oil extraction which, as a rule, is used to develop nontraditional collectors. It is assumed that the complicated character of HFF fractures significantly influences the fracture geometry in the rock matrix. Numerous theoretical models proposed to predict the fracture geometry and the character of interaction of mechanical stresses in the multistage HFF have not been proved experimentally. In this paper, we present the results of laboratory modeling of the multistage HFF performed on a contemporary laboratory-scale plant in the triaxial stress state by using a gel-solution as the HFF agent. As a result of the experiment, a fracturing pattern was formed in the cubic specimen of the model material. The laboratory results showed that a nearly plane fracture is formed at the firstHFF stage, while a concave fracture is formed at the second HFF stage. The interaction of the stress fields created by the two principal HFF fractures results in the growth of secondary fractures whose directions turned out to be parallel to the modeled well bore. But this stress interference leads to a decrease in the width of the second principal fracture. It is was discovered that the penny-shaped fracture model is more appropriate for predicting the geometry of HFF fractures in horizontal wells than the two-dimensional models of fracture propagation (PKN model, KGD model). A computational experiment based on the boundary element method was carried out to obtain the qualitative description of the multistage HFF processes. As a result, a mechanical model of fracture propagation was constructed,which was used to obtain the mechanical stress field (the stress contrast) and the fracture opening angle distribution over fracture length and fracture orientation direction. The conclusions made in the laboratory modeling of the multistage HFF technology agree well with the

Effect of terfenadine on nasal, eustachian tube, and pulmonary function after provocative intranasal histamine challenge.

PubMed

Skoner, D P; Doyle, W J; Boehm, S; Fireman, P

1991-12-01

Previous studies have documented that intranasal histamine challenge results in nasal and eustachian tube obstruction (ETO) in human volunteers. The purpose of the present study was to assess the effect of pretreatment with terfenadine, a nonsedating antihistamine on the pathophysiologic consequences of intranasal histamine challenge. Fifteen subjects with allergic rhinitis were challenged intranasally with saline and increasing histamine doses (0.01, 0.1, 0.5, 1.0, 5.0, and 10.0 mg) before pretreatment (baseline) and after 1 week of pretreatment with terfenadine, 60 mg b.i.d., terfenadine, 120 mg b.i.d., and placebo. Nasal conductance as measured by posterior rhinomanometry showed a dose-dependent, monotonic decrease following sequential administration of the histamine solutions, but there were no apparent differences in the average responses among the four challenge sessions. The frequency of ETO after histamine challenge was decreased by pretreatment with both doses of terfenadine, although this was not significant. Histamine-induced sneezing and rhinorrhea, but not congestion, were significantly reduced by terfenadine pretreatment. There was no evidence of extension of the histamine effects to the lower airway. The results of the present study suggest that terfenadine, a nonsedating antihistamine, had a favorable effect on sneezing and rhinorrhea after provocative intranasal histamine challenge, but did not significantly attenuate the subjective or objective nasal and ET obstructive responses.

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

PubMed

Caspeta, Luis; Nielsen, Jens

2015-07-21

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

Thermal Stress Awareness, Self-Study #18649

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chochoms, Michael

Thermal stresses can expose individuals to a variety of health hazards at work, home, and play. Every year thermal stresses cause severe injuries and death to a large range of people, from elderly people in cities during summer heat waves to young people engaged in winter mountaineering. Awareness is the key to preventing the health hazards associated with thermal stresses. This course is designed for personnel at Los Alamos National Laboratory (LANL). It addresses both heat and cold stresses and discusses their factors, signs and symptoms, treatments, and controls.

Stress changes ahead of an advancing tunnel

USGS Publications Warehouse

Abel, J.F.; Lee, F.T.

1973-01-01

Instrumentation placed ahead of three model tunnels in the laboratory and ahead of a crosscut driven in a metamorphic rock mass detected stress changes several tunnel diameters ahead of the tunnel face. Stress changes were detected 4 diameters ahead of a model tunnel drilled into nearly elastic acrylic, 2??50 diameters ahead of a model tunnel drilled into concrete, and 2 diameters ahead of a model tunnel drilled into Silver Plume Granite. Stress changes were detected 7??50 diameters ahead of a crosscut driven in jointed, closely foliated gneisses and gneissic granites in an experimental mine at Idaho Springs, Colorado. These results contrast markedly with a theoretical elastic estimate of the onset of detectable stress changes at 1 tunnel diameter ahead of the tunnel face. A small compressive stress concentration was detected 2 diameters ahead of the model tunnel in acrylic, 1.25 diameters ahead of the model tunnel in concrete, and 1 diameter ahead of the model tunnel in granite. A similar stress peak was detected about 6 diameters ahead of the crosscut. No such stress peak is predicted from elastic theory. The 3-dimensional in situ stress determined in the field demonstrate that geologic structure controls stress orientations in the metamorphic rock mass. Two of the computed principal stresses are parallel to the foliation and the other principal stress is normal to it. The principal stress orientations vary approximately as the foliation attitude varies. The average horizontal stress components and the average vertical stress component are three times and twice as large, respectively, as those predicted from the overburden load. An understanding of the measured stress field appears to require the application of either tectonic or residual stress components, or both. Laboratory studies indicate the presence of proportionately large residual stresses. Mining may have triggered the release of strain energy, which is controlled by geologic structure. ?? 1973.

Seacoast stress corrosion cracking of aluminum alloys

NASA Technical Reports Server (NTRS)

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

1981-01-01

The stress corrosion cracking resistance of high strength, wrought aluminum alloys in a seacoast atmosphere was investigated and the results were compared with those obtained in laboratory tests. Round tensile specimens taken from the short transverse grain direction of aluminum plate and stressed up to 100 percent of their yield strengths were exposed to the seacoast and to alternate immersion in salt water and synthetic seawater. Maximum exposure periods of one year at the seacoast, 0.3 or 0.7 of a month for alternate immersion in salt water, and three months for synthetic seawater were indicated for aluminum alloys to avoid false indications of stress corrosion cracking failure resulting from pitting. Correlation of the results was very good among the three test media using the selected exposure periods. It is concluded that either of the laboratory test media is suitable for evaluating the stress corrosion cracking performance of aluminum alloys in seacoast atmosphere.

Remote detection of air pollution stress to vegetation - Laboratory-level studies

NASA Technical Reports Server (NTRS)

Westman, Walter E.; Price, Curtis V.

1987-01-01

An experimental investigation of the role of leaf chemistry, anatomy, moisture content, and canopy density on spectral reflectance in healthy and pollution stressed western conifer needles and broad-leafed species of California coastal sage scrub is presented. Acid mist at a level of pH 2.0 is found to more severely effect chlorophyll loss and leaf death than ozone at a level of 0.2 ppm for a four-week period. Both pollutants cause water loss, affecting Bands 4 and 5 in nonlinear ways. The infrared bands initially rise as free water is lost, and subsequently, scattering and reflectance decline. The net effect is shown to be a reduction in TM 4/3 and a rise in TM 5/4 with pollution stress. Under more severe pollution stresses, the decline of leaf area indices due to accelerated leaf drop accentuates the expected TM 4/3 and TM 5/4 changes.

The Boulby Geoscience Project Underground Research Laboratory: Initial Results of a Rock Mechanics Laboratory Testing Programme

NASA Astrophysics Data System (ADS)

Brain, M. J.; Petley, D. N.; Rosser, N.; Lim, M.; Sapsford, M.; Barlow, J.; Norman, E.; Williams, A.; Pybus, D.

2009-12-01

The Boulby Mine, which is situated on the northeast coast of England, is a major source of potash, primarily for use as a fertiliser, with a secondary product of rock salt (halite), used in highway deicing. The deposits are part of the Zechstein formation and are found at depths of between c.1100 and 1135 m below sea level. The evaporite sequence also contains a range of further lithologies, including anhydrite, dolomite and a mixed evaporate deposit. From a scientific perspective the dry, uncontaminated nature of the deposits, the range of lithologies present and the high stress conditions at the mine provide a unique opportunity to observe rock deformation in situ in varying geological and stress environments. To this end the Boulby Geoscience Project was established to examine the feasibility of developing an underground research laboratory at the mine. Information regarding the mechanical properties of the strata at the Boulby Mine is required to develop our understanding of the strength and deformation behaviour of the rock over differing timescales in response to variations in the magnitude and duration of applied stresses. As such data are currently limited, we have developed a laboratory testing programme that examines the behaviour of the deposits during the application of differential compressive stresses. We present the initial results of this testing programme here. Experiments have been carried out using a high pressure Virtual Infinite Strain (VIS) triaxial apparatus (250 kN maximum axial load; 64 MPa maximum cell pressure) manufactured by GDS Instruments. Conventional compression tests under uniaxial and triaxial conditions have been undertaken to determine the effects of axial stress application rate, axial strain rate and confining pressure on behaviour and failure mechanisms. The experimental programme also includes advanced testing into time-dependent creep behaviour under constant deviatoric stress; the effects of variations in temperature and

Teaching Stress Physiology Using Zebrafish ("Danio Rerio")

ERIC Educational Resources Information Center

Cooper, Michael; Dhawale, Shree; Mustafa, Ahmed

2009-01-01

A straightforward and inexpensive laboratory experiment is presented that investigates the physiological stress response of zebrafish after a 5 degree C increase in water temperature. This experiment is designed for an undergraduate physiology lab and allows students to learn the scientific method and relevant laboratory techniques without causing…

Voice stress analysis and evaluation

NASA Astrophysics Data System (ADS)

Haddad, Darren M.; Ratley, Roy J.

2001-02-01

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

Preliminary observations on the impact of complex stress histories on sandstone response to salt weathering: laboratory simulations of process combinations

NASA Astrophysics Data System (ADS)

McCabe, S.; Smith, B. J.; Warke, P. A.

2007-03-01

Historic sandstone structures carry an inheritance, or a ‘memory’, of past stresses that the stone has undergone since its placement in a façade. This inheritance, which conditions present day performance, may be made up of long-term exposure to a combination of low magnitude background environmental factors (for example, salt weathering, temperature and moisture cycling) and, superimposed upon these, less frequent but potentially high magnitude events or ‘exceptional’ factors (for example, lime rendering, severe frost events, fire). The impact of complex histories on the decay pathways of historic sandstone is not clearly understood, but this paper seeks to improve that understanding through the use of a laboratory ‘process combination’ study. Blocks of quartz sandstone (Peakmoor, from NW England) were divided into subsets that experienced different histories (lime rendering and removal, fire and freeze-thaw cycles in isolation and combination) that reflected the event timeline of a real medieval sandstone monument in NE Ireland, Bonamargy Friary (McCabe et al. 2006b). These subsets were then subject to salt weathering cycles using a 10% salt solution of NaCl and MgSO4 that represents the ‘every-day’ stress environment of, for example, sandstone structures in coastal, or polluted urban, location. Block response to salt weathering was monitored by collecting, drying and weighing the debris that was released as blocks were immersed in the salt solution at the beginning of each cycle. The results illustrate the complexity of the stone decay system, showing that seemingly small variations in stress history can produce divergent response to salt weathering cycles. Applied to real-world historic sandstone structures, this concept may help to explain the spatial and temporal variability of sandstone response to background environmental factors on a single façade, and encourage conservators to include the role of stress inheritance when selecting and

Good Stress, Bad Stress and Oxidative Stress: Insights from Anticipatory Cortisol Reactivity

PubMed Central

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

2014-01-01

Chronic psychological stress appears to accelerate biological aging, and oxidative damage is an important potential mediator of this process. However, the mechanisms by which psychological stress promotes oxidative damage are poorly understood. This study investigates the theory that cortisol increases in response to an acutely stressful event have the potential to either enhance or undermine psychobiological resilience to oxidative damage, depending on the body's prior exposure to chronic psychological stress. In order to achieve a range of chronic stress exposure, forty-eight post-menopausal women were recruited in a case-control design that matched women caring for spouses with dementia (a chronic stress model) with similarly aged control women whose spouses were healthy. Participants completed a questionnaire assessing perceived stress over the previous month and provided fasting blood. Three markers of oxidative damage were assessed: 8-iso-prostaglandin F2α (IsoP), lipid peroxidation, 8-hydroxyguanosine (8-OxoG) and 8-hydroxy-2′-deoxyguanosine (8-OHdG), reflecting oxidative damage to RNA/DNA respectively. Within approximately one week, participants completed a standardized acute laboratory stress task while salivary cortisol responses were measured. The increase from 0 to 30 min was defined as “peak” cortisol reactivity, while the increase from 0 to 15 min was defined as “anticipatory” cortisol reactivity, representing a cortisol response that began while preparing for the stress task. Women under chronic stress had higher 8-oxoG, oxidative damage to RNA (p<.01). A moderated mediation model was tested, in which it was hypothesized that heightened anticipatory cortisol reactivity would mediate the relationship between perceived stress and elevated oxidative stress damage, but only among women under chronic stress. Consistent with this model, bootstrapped path analysis found significant indirect paths from perceived stress to 8-OxoG and IsoP (but not

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

PubMed

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

2013-09-01

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

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

PubMed

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

2017-10-28

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

Hypothalamic-Pituitary-Adrenal Reactivity to Acute Stress: an Investigation into the Roles of Perceived Stress and Family Resources.

PubMed

Obasi, Ezemenari M; Shirtcliff, Elizabeth A; Cavanagh, Lucia; Ratliff, Kristen L; Pittman, Delishia M; Brooks, Jessica J

2017-11-01

Rurally situated African Americans suffer from chronic exposure to stress that may have a deleterious effect on health outcomes. Unfortunately, research on potential mechanisms that underlie health disparities affecting the African American community has received limited focus in the scientific literature. This study investigated the relationship between perceived stress, family resources, and cortisol reactivity to acute stress. A rural sample of African American emerging adults (N = 60) completed a battery of assessments, the Trier Social Stress Test (TSST), and provided four samples of salivary cortisol: prior to receiving TSST instructions, prior to conducting the speech task, immediately following the TSST, and 15-20 min following the TSST. As predicted, cortisol levels increased in response to a controlled laboratory inducement of acute stress. Moreover, diminished levels of family resources were associated with blunted cortisol reactivity to acute stress. Of note, higher levels of perceived stress over the past month and being male were independently associated with lower levels of cortisol at baseline. Lack of family resources had a blunting relationship on the hypothalamic-pituitary-adrenal axis reactivity. These findings provide biomarker support for the relationship between family resources-an indicator associated with social determinants of health-and stress physiology within a controlled laboratory experiment. Identifying mechanisms that work toward explanation of within-group differences in African American health disparities is both needed and informative for culturally informed prevention and intervention efforts.

Autonomic, endocrine and behavioural responses to thunder in laboratory and companion dogs.

PubMed

Franzini de Souza, Carla Caroline; Maccariello, Carolina Elisabetta Martins; Dias, Daniel Penteado Martins; Almeida, Norma Aparecida Dos Santos; Medeiros, Magda Alves de

2017-02-01

Dogs are highly sensitive to sound stimuli, especially fireworks, firearms, and thunder, and therefore these sounds are used as models of stress reactivity in dogs. Companion and laboratory dogs may respond differently to stressful stimuli, due to differences in management and their relationship with humans. Therefore, the reactivity of beagle dogs (laboratory) and companion dogs to an acute acoustic stress model was studied by analysing the heart rate variability (HRV; cardiac interval values), serum cortisol levels and various behavioural parameters. Eight beagles and six privately owned dogs with no history of phobia to thunder were used. The sound stimulus consisted of a standardized recording of thunder for 2.5min with a maximum intensity of 103-104dB. To evaluate the HRV, cardiac intervals were recorded using a frequency meter (Polar RS800CX model), and later the data were analysed using CardioSeries 2.4.1 software. In both laboratory and companion dogs, thunder promoted an increase in the power of the LF band of the cardiac interval spectrum, in the LF/HF ratio and in the HR, and a decrease in the power of the HF band of the cardiac interval spectrum. Companion dogs showed higher cortisol levels, than beagles, independently of the time point studied and a significant increase in the cortisol levels 15min after acoustic stress, while beagles did not show any alterations in their cortisol levels in response to the sound. On the other hand, beagles showed higher scores in the trembling, hiding, vigilance, running, salivation, bolting and startle parameters than companion dogs. Our results showed that independently of the sound stimulus, companion dogs had higher cortisol levels than laboratory dogs. Furthermore, the sound stimulus induced a marked autonomic imbalance towards sympathetic predominance in both laboratory and companion dogs. However a significant increase in the cortisol was observed only in companion dogs. On the other hand, in general the

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

PubMed

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

2011-11-01

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

The role of frontal EEG asymmetry in post-traumatic stress disorder.

PubMed

Meyer, Thomas; Smeets, Tom; Giesbrecht, Timo; Quaedflieg, Conny W E M; Smulders, Fren T Y; Meijer, Ewout H; Merckelbach, Harald L G J

2015-05-01

Frontal alpha asymmetry, a biomarker derived from electroencephalography (EEG) recordings, has often been associated with psychological adjustment, with more left-sided frontal activity predicting approach motivation and lower levels of depression and anxiety. This suggests high relevance to post-traumatic stress disorder (PTSD), a disorder comprising anxiety and dysphoria symptoms. We review this relationship and show that frontal asymmetry can be plausibly linked to neuropsychological abnormalities seen in PTSD. However, surprisingly few studies (k = 8) have directly addressed frontal asymmetry in PTSD, mostly reporting that trait frontal asymmetry has little (if any) predictive value. Meanwhile, preliminary evidence suggest that state-dependent asymmetry during trauma-relevant stimulation distinguishes PTSD patients from resilient individuals. Thus, exploring links between provocation-induced EEG asymmetry and PTSD appears particularly promising. Additionally, we recommend more fine-grained analyses into PTSD symptom clusters in relation to frontal asymmetry. Finally, we highlight hypotheses that may guide future research and help to fully apprehend the practical and theoretical relevance of this biological marker. Copyright © 2015 Elsevier B.V. All rights reserved.

Short-term secretory regulation of ghrelin during growth hormone provocative tests in prepubertal children with various growth hormone secretory capacities.

PubMed

Matsuoka, Hisafumi; Hosoda, Hiroshi; Sugawara, Hisae; Iwama, Saika; Kim, Hye Sook; Kangawa, Kenji; Sugihara, Shigetaka

2005-01-01

Ghrelin is a novel gastric peptide which stimulates GH secretion and has been demonstrated to have orexigenic and adipogenic properties. Insulin is a physiological and dynamic modulator of plasma ghrelin, and insulinemia possibly mediates the effect of the nutritional state on the plasma concentrations of ghrelin in adults. No data on the regulation of GH secretion by ghrelin have so far been reported, nor has the possible influence of hypoglycemia on the plasma ghrelin levels in children been reported. Provocative studies were performed using a variety of stimuli, including insulin-induced hypoglycemia, and glucagon, arginine and L-dopa loading. We studied a group of 27 children with short stature being investigated for GH deficiency (10 F, 17 M; age 4-14 years; height SDS -0.92 to -3.27); the subjects were instructed to fast overnight, and the following morning, the relationships among the plasma ghrelin, GH and glucose levels were investigated by determining the plasma ghrelin profiles during those provocative tests. Using a new method for determining the two types of ghrelin, samples were obtained for determination of the plasma ghrelin, serum glucose and serum GH levels after the administration of the aforementioned stimulating agents. All the four stimuli caused a significant decrease in the circulating C- and N-ghrelin levels with a nadir at +30 min, with the exception of the N-ghrelin level following the L-dopa loading. During the same period, the plasma GH level increased following insulin, arginine and L-dopa loading, and the plasma glucose level increased significantly following glucagon loading. In the arginine and L-dopa load connected, a significant correlation was observed between the 30-min change in the serum GH level and the 30-min change in the plasma C-ghrelin level. In the multiple regression analysis to explain the 30-min change in the plasma level of C-ghrelin, the baseline plasma level of C-ghrelin (basal), height and % overweight were the

"Cumulative Stress": The Effects of Maternal and Neonatal Oxidative Stress and Oxidative Stress-Inducible Genes on Programming of Atopy.

PubMed

Manti, Sara; Marseglia, Lucia; D'Angelo, Gabriella; Cuppari, Caterina; Cusumano, Erika; Arrigo, Teresa; Gitto, Eloisa; Salpietro, Carmelo

2016-01-01

Although extensive epidemiological and laboratory studies have been performed to identify the environmental and immunological causes of atopy, genetic predisposition seems to be the biggest risk factor for allergic diseases. The onset of atopic diseases may be the result of heritable changes of gene expression, without any alteration in DNA sequences occurring in response to early environmental stimuli. Findings suggest that the establishment of a peculiar epigenetic pattern may also be generated by oxidative stress (OS) and perpetuated by the activation of OS-related genes. Analyzing the role of maternal and neonatal oxidative stress and oxidative stress-inducible genes, the purpose of this review was to summarize what is known about the relationship between maternal and neonatal OS-related genes and the development of atopic diseases.

Effect of Pet Dogs on Children’s Perceived Stress and Cortisol Stress Response

PubMed Central

Kertes, Darlene A.; Liu, Jingwen; Hall, Nathan J.; Hadad, Natalie A.; Wynne, Clive D. L.; Bhatt, Samarth S.

2016-01-01

The present study tested whether pet dogs have stress-buffering effects for children during a validated laboratory-based protocol, the Trier Social Stress Test for Children (TSST-C). Participants were 101 children aged 7–12 years with their primary caregivers and pet dogs. Children were randomly assigned in the TSST-C to a pet present condition or one of two comparison conditions: parent present or no support figure present. Baseline, response, and recovery indices of perceived stress and cortisol levels were computed based on children’s self-reported feelings of stress and salivary cortisol. Results indicated that in the alone (no social support) condition, children showed the expected rise for both perceived stress and cortisol response to stress. Pet dog presence significantly buffered the perceived stress response in comparison to children in the alone and parent present conditions. No main condition effect was observed for cortisol; however, for children experiencing the stressor with their pet present, lower cortisol response to stress was associated with more child-initiated petting and less dog proximity-seeking behavior. The results support the notion that pet dogs can provide socio-emotional benefits for children via stress buffering. PMID:28439150

Lower Electrodermal Activity to Acute Stress in Caregivers of People with Autism Spectrum Disorder: An Adaptive Habituation to Stress

ERIC Educational Resources Information Center

Ruiz-Robledillo, Nicolás; Moya-Albiol, Luis

2015-01-01

Caring for a relative with autism spectrum disorder (ASD) entails being under chronic stress that could alter body homeostasis. Electrodermal activity (EDA) is an index of the sympathetic activity of the autonomic nervous system related to emotionality and homeostasis. This study compares EDA in response to acute stress in the laboratory between…

Effect of nasal noninvasive respiratory support methods on pharyngeal provocation-induced aerodigestive reflexes in infants.

PubMed

Jadcherla, Sudarshan R; Hasenstab, Kathryn A; Sitaram, Swetha; Clouse, Brian J; Slaughter, Jonathan L; Shaker, Reza

2016-06-01

The pharynx is a locus of provocation among infants with aerodigestive morbidities manifesting as dysphagia, life-threatening events, aspiration-pneumonia, atelectasis, and reflux, and such infants often receive nasal respiratory support. We determined the impact of different oxygen delivery methods on pharyngeal stimulation-induced aerodigestive reflexes [room air (RA), nasal cannula (NC), and nasal continuous positive airway pressure (nCPAP)] while hypothesizing that the sensory motor characteristics of putative reflexes are distinct. Thirty eight infants (28.0 ± 0.7 wk gestation) underwent pharyngoesophageal manometry and respiratory inductance plethysmography to determine the effects of graded pharyngeal stimuli (n = 271) on upper and lower esophageal sphincters (UES, LES), swallowing, and deglutition-apnea. Comparisons were made between NC (n = 19), nCPAP (n = 9), and RA (n = 10) groups. Importantly, NC or nCPAP (vs. RA) had: 1) delayed feeding milestones (P < 0.05), 2) increased pharyngeal waveform recruitment and duration, greater UES nadir pressure, decreased esophageal contraction duration, decreased distal esophageal contraction amplitude, and decreased completely propagated esophageal peristalsis (all P < 0.05), and 3) similarly developed UES contractile and LES relaxation reflexes (P > 0.05). We conclude that aerodigestive reflexes were similarly developed in infants using noninvasive respiratory support with adequate upper and lower aerodigestive protection. Increased concern for GERD is unfounded in this population. These infants may benefit from targeted oromotor feeding therapies and safe pharyngeal bolus transit to accelerate feeding milestones. Copyright © 2016 the American Physiological Society.

Effect of nasal noninvasive respiratory support methods on pharyngeal provocation-induced aerodigestive reflexes in infants

PubMed Central

Hasenstab, Kathryn A.; Sitaram, Swetha; Clouse, Brian J.; Slaughter, Jonathan L.; Shaker, Reza

2016-01-01

The pharynx is a locus of provocation among infants with aerodigestive morbidities manifesting as dysphagia, life-threatening events, aspiration-pneumonia, atelectasis, and reflux, and such infants often receive nasal respiratory support. We determined the impact of different oxygen delivery methods on pharyngeal stimulation-induced aerodigestive reflexes [room air (RA), nasal cannula (NC), and nasal continuous positive airway pressure (nCPAP)] while hypothesizing that the sensory motor characteristics of putative reflexes are distinct. Thirty eight infants (28.0 ± 0.7 wk gestation) underwent pharyngoesophageal manometry and respiratory inductance plethysmography to determine the effects of graded pharyngeal stimuli (n = 271) on upper and lower esophageal sphincters (UES, LES), swallowing, and deglutition-apnea. Comparisons were made between NC (n = 19), nCPAP (n = 9), and RA (n = 10) groups. Importantly, NC or nCPAP (vs. RA) had: 1) delayed feeding milestones (P < 0.05), 2) increased pharyngeal waveform recruitment and duration, greater UES nadir pressure, decreased esophageal contraction duration, decreased distal esophageal contraction amplitude, and decreased completely propagated esophageal peristalsis (all P < 0.05), and 3) similarly developed UES contractile and LES relaxation reflexes (P > 0.05). We conclude that aerodigestive reflexes were similarly developed in infants using noninvasive respiratory support with adequate upper and lower aerodigestive protection. Increased concern for GERD is unfounded in this population. These infants may benefit from targeted oromotor feeding therapies and safe pharyngeal bolus transit to accelerate feeding milestones. PMID:27012774

Laboratory-based maximum slip rates in earthquake rupture zones and radiated energy

USGS Publications Warehouse

McGarr, A.; Fletcher, Joe B.; Boettcher, M.; Beeler, N.; Boatwright, J.

2010-01-01

Laboratory stick-slip friction experiments indicate that peak slip rates increase with the stresses loading the fault to cause rupture. If this applies also to earthquake fault zones, then the analysis of rupture processes is simplified inasmuch as the slip rates depend only on the local yield stress and are independent of factors specific to a particular event, including the distribution of slip in space and time. We test this hypothesis by first using it to develop an expression for radiated energy that depends primarily on the seismic moment and the maximum slip rate. From laboratory results, the maximum slip rate for any crustal earthquake, as well as various stress parameters including the yield stress, can be determined based on its seismic moment and the maximum slip within its rupture zone. After finding that our new equation for radiated energy works well for laboratory stick-slip friction experiments, we used it to estimate radiated energies for five earthquakes with magnitudes near 2 that were induced in a deep gold mine, an M 2.1 repeating earthquake near the San Andreas Fault Observatory at Depth (SAFOD) site and seven major earthquakes in California and found good agreement with energies estimated independently from spectra of local and regional ground-motion data. Estimates of yield stress for the earthquakes in our study range from 12 MPa to 122 MPa with a median of 64 MPa. The lowest value was estimated for the 2004 M 6 Parkfield, California, earthquake whereas the nearby M 2.1 repeating earthquake, as recorded in the SAFOD pilot hole, showed a more typical yield stress of 64 MPa.

Relationship between stress wave velocities of green and dry veneer

Treesearch

Brian K. Brashaw; Xiping Wang; Robert J. Ross; Roy F. Pellerin

2004-01-01

This paper evaluates the relationship between the stress wave velocities of green and dry southern pine and Douglas-fir veneers. A commercial stress wave timer and a laboratory signal analysis system were used to measure the transit time required for an induced stress wave to travel the longitudinal length of each veneer. Stress wave transit times were measured in the...

Housing environment influences stress-related hippocampal substrates and depression-like behavior.

PubMed

Ashokan, Archana; Hegde, Akshaya; Balasingham, Anushanthy; Mitra, Rupshi

2018-03-15

Rats are widely used animal models for biological psychiatry and neuroscience. Laboratory rats are typically housed in impoverished sensory environments. The lack of species-typical sensory environment might radically change the response of individual animals to stressful and/or threatening episodes. In this report, we demonstrate that behavioral and neural sequelae of chronic stress were modified by sensory environment of adult male rats. This includes effects of stress on the density of spines on CA3 hippocampal neurons, hippocampal neurogenesis and abundance of glucocorticoid or mineralocorticoid receptors. Enrichment also reduced depression-like behavior in a forced swim task. Stress and sensory enrichment evoked opposing effects on all the above endpoints. The sensory enrichment used in this report is of a relatively short duration provided during adulthood. This period excludes critical windows of greater plasticity during pre- and peripubertal stages. Our results suggest that standard housing practices for laboratory rats remain austere concerning sensory requirements of this species. Thus, even a moderate sensory enrichment is capable of reducing high stress-sensitivity and depressive-like behavior in standard laboratory rats. Copyright © 2018. Published by Elsevier B.V.

Comorbid Latent Adrenal Insufficiency with Autoimmune Thyroid Disease.

PubMed

Yamamoto, Toshihide

2015-09-01

Autoimmune thyroid disease (ATD) has been occasionally observed in patients with primary adrenal insufficiency (PAI). In contrast, less than 20 cases of comorbid PAI with ATD have been found in the English literature. One conceivable reason is difficulty in detecting latent PAI. Information of clinical presentation and diagnostics is sought to facilitate diagnosis of latent PAI. Latent PAI was pursued in 11 patients among 159 ATD patients. All of them were maintained in a euthyroid state. Except for one patient with nonrheumatic musculoskeletal symptoms, the other patients, who were asymptomatic in their daily lives, presented with recurrent nonspecific gastrointestinal symptoms or fatigue in stress-associated circumstances. Morning cortisol level <303 nmol/l was used as an inclusion criterion. Their basal adrenocorticotropic hormone levels were normal. The adrenal status was examined by a provocation test, either an insulin-induced hypoglycemia test or a 1-μg intravenous corticotrophin test. Eleven patients showed subnormal cortisol response. They were supplemented with hydrocortisone of doses ≤15 mg/day. After a few months of supplementation, PAI was confirmed by another provocation test. Three patients were excluded because of dissociation of two provocation tests. Comorbid latent PAI with ATD was pursued from the symptoms stated above and proven by two provocation tests; it was found in 5% (8/159) of the patients. When patients with ATD are troubled by recurrent stress-associated gastrointestinal or constitutional symptoms or nonrheumatic musculoskeletal symptoms which have remained unrelieved by adjustment of thyroid medication, these symptoms may be a manifestation of comorbid latent PAI. It is worth investigating such patients for latent PAI.

Developing a cardiopulmonary exercise testing laboratory.

PubMed

Diamond, Edward

2007-12-01

Cardiopulmonary exercise testing is a noninvasive and cost-effective technique that adds significant value to the assessment and management of a variety of symptoms and diseases. The penetration of this testing in medical practice may be limited by perceived operational and financial barriers. This article reviews coding and supervision requirements related to both simple and complex pulmonary stress testing. A program evaluation and review technique diagram is used to describe the work flow process. Data from our laboratory are used to generate an income statement that separates fixed and variable costs and calculates the contribution margin. A cost-volume-profit (break-even) analysis is then performed. Using data from our laboratory including fixed and variable costs, payer mix, reimbursements by payer, and the assumption that the studies are divided evenly between simple and complex pulmonary stress tests, the break-even number is calculated to be 300 tests per year. A calculator with embedded formulas has been designed by the author and is available on request. Developing a cardiopulmonary exercise laboratory is challenging but achievable and potentially profitable. It should be considered by a practice that seeks to distinguish itself as a quality leader. Providing this clinically valuable service may yield indirect benefits such as increased patient volume and increased utilization of other services provided by the practice. The decision for a medical practice to commit resources to managerial accounting support requires a cost-benefit analysis, but may be a worthwhile investment in our challenging economic environment.

The Plant Genetic Engineering Laboratory For Desert Adaptation

NASA Astrophysics Data System (ADS)

Kemp, John D.; Phillips, Gregory C.

1985-11-01

The Plant Genetic Engineering Laboratory for Desert Adaptation (PGEL) is one of five Centers of Technical Excellence established as a part of the state of New Mexico's Rio Grande Research Corridor (RGRC). The scientific mission of PGEL is to bring innovative advances in plant biotechnology to bear on agricultural productivity in arid and semi-arid regions. Research activities focus on molecular and cellular genetics technology development in model systems, but also include stress physiology investigations and development of desert plant resources. PGEL interacts with the Los Alamos National Laboratory (LANL), a national laboratory participating in the RGRC. PGEL also has an economic development mission, which is being pursued through technology transfer activities to private companies and public agencies.

Stress, Interviewer Support, and Children's Eyewitness Identification Accuracy

ERIC Educational Resources Information Center

Rush, Elizabeth B.; Quas, Jodi A.; Yim, Ilona S.; Nikolayev, Mariya; Clark, Steven E.; Larson, Rakel P.

2014-01-01

Few studies have investigated how stress affects eyewitness identification capabilities across development, and no studies have investigated whether retrieval context in conjunction with stress affects accuracy. In this study, one hundred fifty-nine 7- to 8- and 12- to 14-year-olds completed a high- or low-stress laboratory protocol during which…

Organism/Organic Exposure to Orbital Stresses (OOREOS) Satellite: Radiation Exposure in LEO and Supporting Laboratory Studies

NASA Technical Reports Server (NTRS)

Mattioda, Andrew Lige; Cook, Amanda Marie; Quinn, Richard C.; Elsaesser, Andreas; Ehrenfreund, Pascale; Ricca,Alessandra; Jones, Nykola C.; Hoffman, Soren; Ricco,Antonio

2014-01-01

We will present the results from the exposure of the metalloporphyrin iron tetraphenylporphyrin chloride (FeTPPCI), anthraufin (C(sub 14)H(sub 8)(O sub 4) (Anth) and Isoviolanthrene (C(sub 34H sub 18) (IVA) to the outher space environment, measured in situ aboard the Organism/Organic Exposure to Orbital Stresses nanosatellite. The compounds were exposed for a period of 17 months (3700 hours of direct solar exposure) including broad-spectrum solar radiation (approx. 122 nm to the near infrared). The organic films are enclosed in hermetically sealed sample cells that contain one of four astrobiologically relevant microenvironments. Transmission spectra (200-1000 nm) were recorded for each film, at first daily and subsequently every 15 days, along with a solar spectrum and the dark response of the detector array. In addition to analysis via UV-Vis spectroscopy, the laboratory controls were also monitored via infrared and far-UV spectroscopy. The results presented will include the finding that the FeTPPCI and IVA organic films in contact with a humid headspace gas (0.8-2.3%) exhibit faster degradation times, upon irradiation, in comparison with identical films under dry headspaces gases, whereas the Anth thin film exhibited a higher degree of photostability. In the companion laboratory experiments, simulated solar exposure of FeTPI films in contact with either Ar or CO(sub -2):O(sub -2):Ar (10:0.01:1000) headspace gas results in growth of a band in the films infrared spectra at 1961 cm(sup 1). Our assignment of this new spectral feature and the corresponding rational will be presented. The relevance of O/OREOS findings to planetary science, biomarker research, and the photostability of organic materials in astrobiologically relevant environments will also be discussed.

Impact of NASA Stress Laboratory Program on US Colleges

NASA Technical Reports Server (NTRS)

Delisser, S. P.

1971-01-01

A programmatic narrative of the effects of NASA stress lab program on physical education in U.S. schools and colleges is presented. Individual non-structured programs were set up where students participate during his or her free time. The program is also in accordance with the medical history of the student. Preliminary results indicate more student interest and participation in the program and that students are generally more physically fit than in previous structured programs.

Body Weight Changes of Laboratory Animals during Transportation

PubMed Central

Lee, Sunghak; Nam, Hyunsik; Kim, Jinsung; Cho, Hyejung; Jang, Yumi; Lee, Eunjung; Choi, Eunsung; Jin, Dong Il; Moon, Hongsik

2012-01-01

The majority of laboratory animals were transported from commercial breeders to a research facility by ground transportation. During the transportation, many biological functions and systems can be affected by stress. In this experiment, the change of body weight during the transportation was measured and the recovery periods from the transportation stress established based on the body weight changes. Total 676 laboratory animals which were aged between 3 to 9 wk old were studied. The transportation time taken from container packing to unpacking the container was approximately 24 h. The temperature of animal container was constantly maintained by air-conditioning and heating equipment. Rats were found to be more sensitive than mice. The body weight of rats was significantly decreased 3.71% (p<0.05) compared to the body weight of mice which decreased 0.9% There was no significant difference between the strains in the same species. When the changes of body weights were compared between delivery days, C57BL/6 mice showed the most variable changes compared to other species and strains. Consequently, C57BL/6 was more sensitive to stress than the other strains and the transportation process needs to be standardized to reduce between day variability. To establish the recovery periods from transportation stress, the body weight changes were measured during the acclimation period. Although the body weight of animals decreased during transportation, animals recovered their weight loss after the next day. PMID:25049564

Heart Rate and Stress in a College Setting

ERIC Educational Resources Information Center

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…

Assessing the relative importance of environmental effects, carry-over effects and species differences in thermal stress resistance: a comparison of Drosophilids across field and laboratory generations.

PubMed

Schiffer, Michele; Hangartner, Sandra; Hoffmann, Ary A

2013-10-15

There is increasing interest in comparing species of related organisms for their susceptibility to thermal extremes in order to evaluate potential vulnerability to climate change. Comparisons are typically undertaken on individuals collected from the field with or without a period of acclimation. However, this approach does not allow the potential contributions of environmental and carry-over effects across generations to be separated from inherent species differences in susceptibility. To assess the importance of these different sources of variation, we here considered heat and cold resistance in Drosophilid species from tropical and temperate sites in the field and across two laboratory generations. Resistance in field-collected individuals tended to be lower when compared with F1 and F2 laboratory generations, and species differences in field flies were only weakly correlated to differences established under controlled rearing conditions, unlike in F1-F2 comparisons. This reflected large environmental effects on resistance associated with different sites and conditions experienced within sites. For the 8 h cold recovery assay there was no strong evidence of carry-over effects, whereas for the heat knockdown and 2 h cold recovery assays there was some evidence for such effects. However, for heat these were species specific in direction. Variance components for inherent species differences were substantial for resistance to heat and 8 h cold stress, but small for 2 h cold stress, though this may be a reflection of the species being considered in the comparisons. These findings highlight that inherent differences among species are difficult to characterise accurately without controlling for environmental sources of variation and carry-over effects. Moreover, they also emphasise the complex nature of carry-over effects that vary depending on the nature of stress traits and the species being evaluated.

Physiological coherence in healthy volunteers during laboratory-induced stress and controlled breathing.

PubMed

Mejía-Mejía, Elisa; Torres, Robinson; Restrepo, Diana

2018-06-01

Physiological coherence has been related with a general sense of well-being and improvements in health and physical, social, and cognitive performance. The aim of this study was to evaluate the relationship between acute stress, controlled breathing, and physiological coherence, and the degree of body systems synchronization during a coherence-generation exercise. Thirty-four university employees were evaluated during a 20-min test consisting of four stages of 5-min duration each, during which basal measurements were obtained (Stage 1), acute stress was induced using validated mental stressors (Stroop test and mental arithmetic task, during Stage 2 and 3, respectively), and coherence states were generated using a controlled breathing technique (Stage 4). Physiological coherence and cardiorespiratory synchronization were assessed during each stage from heart rate variability, pulse transit time, and respiration. Coherence measurements derived from the three analyzed variables increased during controlled respiration. Moreover, signals synchronized during the controlled breathing stage, implying a cardiorespiratory synchronization was achieved by most participants. Hence, physiological coherence and cardiopulmonary synchronization, which could lead to improvements in health and better life quality, can be achieved using slow, controlled breathing exercises. Meanwhile, coherence measured during basal state and stressful situations did not show relevant differences using heart rate variability and pulse transit time. More studies are needed to evaluate the ability of coherence ratio to reflect acute stress. © 2017 Society for Psychophysiological Research.

Gender specific gene-environment interactions on laboratory-assessed aggression.

PubMed

Verona, Edelyn; Joiner, Thomas E; Johnson, Frank; Bender, Theodore W

2006-01-01

We examined gene-environment interactive effects on aggressive behavior among men and women genotyped (short versus long alleles) for the serotonin transporter gene. Aggressive behavior was indexed via a laboratory paradigm that measured the intensity and duration of shocks delivered to a putative "employee". Half of the participants were exposed to a physical stressor during the procedure (stress) and half were not (no-stress). Participants' physiological responses were gauged via acoustic startle eyeblink reactions (startle reactivity). Results were that men with the homozygous short (s/s) genotype showed increased aggression only under stress, whereas women and men carrying the long allele did not show differences in aggression in stress versus no-stress. However, although stress exposure produced increases in startle reactivity, there were no genotype or gender differences in physiology. These results replicate longitudinal research findings confirming the interactive effects of genes and environment on behavioral reactivity and on the development of externalizing psychopathological syndromes, at least in men.

Laboratory environmental factors and pain behavior: the relevance of unknown unknowns to reproducibility and translation.

PubMed

Mogil, Jeffrey S

2017-03-22

The poor record of basic-to-clinical translation in recent decades has led to speculation that preclinical research is "irreproducible", and this irreproducibility in turn has largely been attributed to deficiencies in reporting and statistical practices. There are, however, a number of other reasonable explanations of both poor translation and difficulties in one laboratory replicating the results of another. This article examines these explanations as they pertain to preclinical pain research. I submit that many instances of apparent irreproducibility are actually attributable to interactions between the phenomena and interventions under study and "latent" environmental factors affecting the rodent subjects. These environmental variables-often causing stress, and related to both animal husbandry and the specific testing context-differ greatly between labs, and continue to be identified, suggesting that our knowledge of their existence is far from complete. In pain research in particular, laboratory stressors can produce great variability of unpredictable direction, as stress is known to produce increases (stress-induced hyperalgesia) or decreases (stress-induced analgesia) in pain depending on its parameters. Much greater attention needs to be paid to the study of the laboratory environment if replication and translation are to be improved.

Evaluation of stress and saturation effects on seismic velocity and electrical resistivity - laboratory testing of rock samples

NASA Astrophysics Data System (ADS)

Vilhelm, Jan; Jirků, Jaroslav; Slavík, Lubomír; Bárta, Jaroslav

2016-04-01

Repository, located in a deep geological formation, is today considered the most suitable solution for disposal of spent nuclear fuel and high-level waste. The geological formations, in combination with an engineered barrier system, should ensure isolation of the waste from the environment for thousands of years. For long-term monitoring of such underground excavations special monitoring systems are developed. In our research we developed and tested monitoring system based on repeated ultrasonic time of flight measurement and electrical resistivity tomography (ERT). As a test site Bedřichov gallery in the northern Bohemia was selected. This underground gallery in granitic rock was excavated using Tunnel Boring Machine (TBM). The seismic high-frequency measurements are performed by pulse-transmission technique directly on the rock wall using one seismic source and three receivers in the distances of 1, 2 and 3 m. The ERT measurement is performed also on the rock wall using 48 electrodes. The spacing between electrodes is 20 centimeters. An analysis of relation of seismic velocity and electrical resistivity on water saturation and stress state of the granitic rock is necessary for the interpretation of both seismic monitoring and ERT. Laboratory seismic and resistivity measurements were performed. One series of experiments was based on uniaxial loading of dry and saturated granitic samples. The relation between stress state and ultrasonic wave velocities was tested separately for dry and saturated rock samples. Other experiments were focused on the relation between electrical resistivity of the rock sample and its saturation level. Rock samples with different porosities were tested. Acknowledgments: This work was partially supported by the Technology Agency of the Czech Republic, project No. TA 0302408

Character strengths, social anxiety, and physiological stress reactivity.

PubMed

Li, Tingting; Duan, Wenjie; Guo, Pengfei

2017-01-01

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

Frictional heating processes during laboratory earthquakes

NASA Astrophysics Data System (ADS)

Aubry, J.; Passelegue, F. X.; Deldicque, D.; Lahfid, A.; Girault, F.; Pinquier, Y.; Escartin, J.; Schubnel, A.

2017-12-01

Frictional heating during seismic slip plays a crucial role in the dynamic of earthquakes because it controls fault weakening. This study proposes (i) to image frictional heating combining an in-situ carbon thermometer and Raman microspectrometric mapping, (ii) to combine these observations with fault surface roughness and heat production, (iii) to estimate the mechanical energy dissipated during laboratory earthquakes. Laboratory earthquakes were performed in a triaxial oil loading press, at 45, 90 and 180 MPa of confining pressure by using saw-cut samples of Westerly granite. Initial topography of the fault surface was +/- 30 microns. We use a carbon layer as a local temperature tracer on the fault plane and a type K thermocouple to measure temperature approximately 6mm away from the fault surface. The thermocouple measures the bulk temperature of the fault plane while the in-situ carbon thermometer images the temperature production heterogeneity at the micro-scale. Raman microspectrometry on amorphous carbon patch allowed mapping the temperature heterogeneities on the fault surface after sliding overlaid over a few micrometers to the final fault roughness. The maximum temperature achieved during laboratory earthquakes remains high for all experiments but generally increases with the confining pressure. In addition, the melted surface of fault during seismic slip increases drastically with confining pressure. While melting is systematically observed, the strength drop increases with confining pressure. These results suggest that the dynamic friction coefficient is a function of the area of the fault melted during stick-slip. Using the thermocouple, we inverted the heat dissipated during each event. We show that for rough faults under low confining pressure, less than 20% of the total mechanical work is dissipated into heat. The ratio of frictional heating vs. total mechanical work decreases with cumulated slip (i.e. number of events), and decreases with

Design, rationale and feasibility of a multidimensional experimental protocol to study early life stress.

PubMed

Bartholomeusz, M Dillwyn; Bolton, Philip S; Callister, Robin; Skinner, Virginia; Hodgson, Deborah

2017-09-01

There is a rapidly accumulating body of evidence regarding the influential role of early life stress (ELS) upon medical and psychiatric conditions. While self-report instruments, with their intrinsic limitations of recall, remain the primary means of detecting ELS in humans, biological measures are generally limited to a single biological system. This paper describes the design, rationale and feasibility of a study to simultaneously measure neuroendocrine, immune and autonomic nervous system (ANS) responses to psychological and physiological stressors in relation to ELS. Five healthy university students were recruited by advertisement. Exclusion criteria included chronic medical conditions, psychotic disorders, needle phobia, inability to tolerate pain, and those using anti-inflammatory medications. They were clinically interviewed and physiological recordings made over a two-hour period pre, during and post two acute stressors: the cold pressor test and recalling a distressing memory. The Childhood Trauma Questionnaire and the Parental Bonding Index were utilised to measure ELS. Other psychological measures of mood and personality were also administered. Measurements of heart rate, blood pressure, respiratory rate, skin conductance, skin blood flow and temporal plasma samples were successfully obtained before, during and after acute stress. Participants reported the extensive psychological and multisystem physiological data collection and stress provocations were tolerable. Most (4/5) participants indicated a willingness to return to repeat the protocol, indicating acceptability. Our protocol is viable and safe in young physically healthy adults and allows us to assess simultaneously neuroendocrine, immune and autonomic nervous system responses to stressors in persons assessed for ELS.

Clinical Perspective of Oxidative Stress in Sporadic ALS

PubMed Central

D’Amico, Emanuele; Factor-Litvak, Pam; Santella, Regina M.; Mitsumoto, Hiroshi

2013-01-01

Sporadic amyotrophic lateral sclerosis (sALS) is one of the most devastating neurological diseases; most patients die within 3 to 4 years after symptom onset. Oxidative stress is a disturbance in the pro-oxidative/anti-oxidative balance favoring the pro-oxidative state. Autopsy and laboratory studies in ALS indicate that oxidative stress plays a major role in motor neuron degeneration and astrocyte dysfunction. Oxidative stress biomarkers in cerebrospinal fluid, plasma, and urine, are elevated, suggesting that abnormal oxidative stress is generated outside of the central nervous system. Our review indicates that agricultural chemicals, heavy metals, military service, professional sports, excessive physical exertion, chronic head trauma, and certain foods might be modestly associated with ALS risk, with a stronger association between risk and smoking. At the cellular level, these factors are all involved in generating oxidative stress. Experimental studies indicate that a combination of insults that induce modest oxidative stress can exert additive deleterious effects on motor neurons, suggesting multiple exposures in real-world environments are important. As the disease progresses, nutritional deficiency, cachexia, psychological stress, and impending respiratory failure may further increase oxidative stress. Moreover, accumulating evidence suggests that ALS is possibly a systemic disease. Laboratory, pathologic, and epidemiologic evidence clearly support the hypothesis that oxidative stress is central in the pathogenic process, particularly in genetically susceptive individuals. If we are to improve ALS treatment, well-designed biochemical and genetic epidemiological studies, combined with a multidisciplinary research approach, are needed and will provide knowledge crucial to our understanding of ALS etiology, pathophysiology, and prognosis. PMID:23797033

Association Between Interleukin-6 and Striatal Prediction-Error Signals Following Acute Stress in Healthy Female Participants.

PubMed

Treadway, Michael T; Admon, Roee; Arulpragasam, Amanda R; Mehta, Malavika; Douglas, Samuel; Vitaliano, Gordana; Olson, David P; Cooper, Jessica A; Pizzagalli, Diego A

2017-10-15

Stress is widely known to alter behavioral responses to rewards and punishments. It is believed that stress may precipitate these changes through modulation of corticostriatal circuitry involved in reinforcement learning and motivation, although the intervening mechanisms remain unclear. One candidate is inflammation, which can rapidly increase following stress and can disrupt dopamine-dependent reward pathways. Here, in a sample of 88 healthy female participants, we first assessed the effect of an acute laboratory stress paradigm on levels of plasma interleukin-6 (IL-6), a cytokine known to be both responsive to stress and elevated in depression. In a second laboratory session, we examined the effects of a second laboratory stress paradigm on reward prediction error (RPE) signaling in the ventral striatum. We show that individual differences in stress-induced increases in IL-6 (session 1) were associated with decreased ventral striatal RPE signaling during reinforcement learning (session 2), though there was no main effect of stress on RPE. Furthermore, changes in IL-6 following stress predicted intraindividual variability in perceived stress during a 4-month follow-up period. Taken together, these data identify a novel link between IL-6 and striatal RPEs during reinforcement learning in the context of acute psychological stress, as well as future appraisal of stressful life events. Copyright © 2017 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Pressure-volume Relationship in the Stress-echocardiography Laboratory: Does (Left Ventricular End-diastolic) Size Matter?

PubMed

Bombardini, Tonino; Mulieri, Louis A; Salvadori, Stefano; Costantino, Marco Fabio; Scali, Maria Chiara; Marzilli, Mario; Picano, Eugenio

2017-02-01

The variation between rest and peak stress end-systolic pressure-volume relation is an afterload-independent index of left ventricular contractility. Whether and to what extent it depends on end-diastolic volume remains unclear. The aim of this study was to assess the dependence of the delta rest-stress end-systolic pressure-volume relation on end-diastolic volume in patients with negative stress echo and all ranges of resting left ventricular function. We analyzed interpretable data obtained in 891 patients (593 men, age 63 ± 12 years) with ejection fraction 47% ± 12%: 338 were normal or near-normal or hypertensive; 229 patients had coronary artery disease; and 324 patients had ischemic or nonischemic dilated cardiomyopathy. They were studied with exercise (n = 172), dipyridamole (n = 482) or dobutamine (n = 237) stress echocardiography. The end-systolic pressure-volume relation was evaluated at rest and peak stress from raw measurement of systolic arterial pressure by cuff sphygmomanometer and end-systolic volume by biplane Simpson rule 2-dimensional echocardiography. Absolute values of delta rest-stress end-systolic pressure-volume relation were higher for exercise and dobutamine than for dipyridamole. In the overall population, an inverse relationship between end-systolic pressure-volume relation and end-diastolic volume was present at rest (r 2 = 0.69, P < .001) and peak stress (r 2 = 0.56, P < .001), but was absent if the delta rest-stress end-systolic pressure-volume relation was considered (r 2 = 0.13). Left ventricular end-diastolic volume does not affect the rest-stress changes in end-systolic pressure-volume relation in either normal or abnormal left ventricles during physical or pharmacological stress. Copyright © 2016 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

A rheological model for elastohydrodynamic contacts based on primary laboratory data

NASA Technical Reports Server (NTRS)

Bair, S.; Winer, W. O.

1979-01-01

A shear rheological model based on primary laboratory data is proposed for concentrated contact lubrication. The model is a Maxwell model modified with a limiting shear stress. Three material properties are required: Low shear stress viscosity, limiting elastic shear modulus, and the limiting shear stress the material can withstand. All three are functions of temperature and pressure. In applying the model to EHD contacts the predicted response possesses the characteristics expected from several experiments reported in the literature and, in one specific case where direct comparison could be made, good numerical agreement is shown.

Failure of Sierra White granite under general states of stress

NASA Astrophysics Data System (ADS)

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

2017-12-01

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

Leptin concentrations in response to acute stress predict subsequent intake of comfort foods

PubMed Central

Tomiyama, A. Janet; Schamarek, Imke; Lustig, Robert H.; Kirschbaum, Clemens; Puterman, Eli; Havel, Peter J.; Epel, Elissa S.

2012-01-01

Both animals and humans show a tendency toward eating more “comfort food” (high fat, sweet food) after acute stress. Such stress eating may be contributing to the obesity epidemic, and it is important to understand the underlying psychobiological mechanisms. Prior investigations have studied what makes individuals eat more after stress; this study investigates what might make individuals eat less. Leptin has been shown to increase following a laboratory stressor, and is known to affect eating behavior. This study examined whether leptin reactivity accounts for individual differences in stress eating. To test this, we exposed forty women to standardized acute psychological laboratory stress (Trier Social Stress Test) while blood was sampled repeatedly for measurements of plasma leptin. We then measured food intake after the stressor in 29 of these women. Increasing leptin during the stressor predicted lower intake of comfort food. These initial findings suggest that acute changes in leptin may be one of the factors modulating down the consumption of comfort food following stress. PMID:22579988

Evolution of Cement-Casing Interface in Wellbore Microannuli under Stress

NASA Astrophysics Data System (ADS)

Matteo, E. N.; Gomez, S. P.; Sobolik, S. R.; Taha, M. R.; Stormont, J.

2017-12-01

Laboratory tests measured the compressibility and flow characteristics of wellbore microannuli. Specimens, consisting of a cement sheath cast on a steel casing with microannuli, were subjected to confining pressures and casing pressures in a pressure vessel that allows simultaneous measurement of gas flow along the axis of the specimen. The flow was interpreted as the hydraulic aperture of the microannuli. We found the hydraulic aperture decreases as confining stress is increased. The larger the initial hydraulic aperture, the more it decreases as confining stress increases. The changes in measured hydraulic aperture correspond to changes of many orders of magnitude in permeability of the wellbore system, suggesting that microannulus response to stress changes may have a significant impact on estimates of wellbore leakage. A finite element model of a wellbore system was developed that included elements representing the microannulus that incorporated the hyperbolic joint model. The thickness of the microannulus elements is equivalent to the hydraulic aperture. The calculated normal stress across the microannulus used in the numerical implementation was found to be similar to the applied confining pressure in the laboratory tests. The microannulus elements were found to reasonably reproduce laboratory behavior during loading from confining pressure increases. The calculated microannulus response to internal casing pressure changes was less stiff than measured, which may be due to hardening of the microannulus during testing. In particular, the microannulus model could be used to estimate CO2 leakage as a function of formation stress changes and/or displacements, or loading from casing expansion or contraction during wellbore operations. Recommendations for future work include an application of the joint model with a thermally active large-scale reservoir coupled with pore pressure caused by dynamic CO2 injection and subsequent microannulus region affects. Sandia

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

EPA Pesticide Factsheets

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

The importance of the cellular stress response in the pathogenesis and treatment of type 2 diabetes.

PubMed

Hooper, Philip L; Balogh, Gabor; Rivas, Eric; Kavanagh, Kylie; Vigh, Laszlo

2014-07-01

Organisms have evolved to survive rigorous environments and are not prepared to thrive in a world of caloric excess and sedentary behavior. A realization that physical exercise (or lack of it) plays a pivotal role in both the pathogenesis and therapy of type 2 diabetes mellitus (t2DM) has led to the provocative concept of therapeutic exercise mimetics. A decade ago, we attempted to simulate the beneficial effects of exercise by treating t2DM patients with 3 weeks of daily hyperthermia, induced by hot tub immersion. The short-term intervention had remarkable success, with a 1 % drop in HbA1, a trend toward weight loss, and improvement in diabetic neuropathic symptoms. An explanation for the beneficial effects of exercise and hyperthermia centers upon their ability to induce the cellular stress response (the heat shock response) and restore cellular homeostasis. Impaired stress response precedes major metabolic defects associated with t2DM and may be a near seminal event in the pathogenesis of the disease, tipping the balance from health into disease. Heat shock protein inducers share metabolic pathways associated with exercise with activation of AMPK, PGC1-a, and sirtuins. Diabetic therapies that induce the stress response, whether via heat, bioactive compounds, or genetic manipulation, improve or prevent all of the morbidities and comorbidities associated with the disease. The agents reduce insulin resistance, inflammatory cytokines, visceral adiposity, and body weight while increasing mitochondrial activity, normalizing membrane structure and lipid composition, and preserving organ function. Therapies restoring the stress response can re-tip the balance from disease into health and address the multifaceted defects associated with the disease.

Effects of trauma-related cues on pain processing in posttraumatic stress disorder: an fMRI investigation

PubMed Central

Mickleborough, Marla J.S.; Daniels, Judith K.; Coupland, Nicholas J.; Kao, Raymond; Williamson, Peter C.; Lanius, Ulrich F.; Hegadoren, Kathy; Schore, Allan; Densmore, Maria; Stevens, Todd; Lanius, Ruth A.

2011-01-01

Background Imaging studies of pain processing in primary psychiatric disorders are just emerging. This study explored the neural correlates of stress-induced analgesia in individuals with posttraumatic stress disorder (PTSD). It combined functional magnetic resonance imaging (fMRI) and the traumatic script-driven imagery symptom provocation paradigm to examine the effects of trauma-related cues on pain perception in individuals with PTSD. Methods The study included 17 patients with PTSD and 26 healthy, trauma-exposed controls. Participants received warm (nonpainful) or hot (painful) thermal stimuli after listening to a neutral or a traumatic script while they were undergoing an fMRI scan at a 4.0 T field strength. Results Between-group analyses revealed that after exposure to the traumatic scripts, the blood oxygen level–dependent (BOLD) signal during pain perception was greater in the PTSD group than the control group in the head of the caudate. In the PTSD group, strong positive correlations resulted between BOLD signal and symptom severity in a number of brain regions previously implicated in stress-induced analgesia, such as the thalamus and the head of the caudate nucleus. Trait dissociation as measured by the Dissociative Experiences Scale correlated negatively with the right amygdala and the left putamen. Limitations This study included heterogeneous traumatic experiences, a different proportion of military trauma in the PTSD versus the control group and medicated patients with PTSD. Conclusion These data indicate that in patients with PTSD trauma recall will lead in a state-dependent manner to greater activation in brain regions implicated in stress-induced analgesia. Correlational analyses lend support to cortical hyperinhibition of the amygdala as a function of dissociation. PMID:20964954

Character strengths, social anxiety, and physiological stress reactivity

PubMed Central

2017-01-01

In this paper, the effects of character strengths on the physiological reactivity to social anxiety induced by the Trier Social Stress Task were reported. On the basis of their scores in the Chinese Virtues Questionnaire, 30 college students were assigned to either high- (n = 15) or low-character-strength (n = 15) groups. Their psychological stress and physiological data across three laboratory stages (namely, baseline, stress exposure, and post-stress) were collected. Results indicated that individuals with high character strengths exhibited rapid cardiovascular recovery from baseline to post-stress even if high- and low-character-strength groups showed similar patterns of cardiovascular arousal in response to the stress at baseline and stress exposure. These results prove that character strengths are stress-defense factors that allow for psychological and physiological adaptation to stress. PMID:28584721

MDMA, cortisol, and heightened stress in recreational ecstasy users.

PubMed

Parrott, Andrew C; Montgomery, Cathy; Wetherell, Mark A; Downey, Luke A; Stough, Con; Scholey, Andrew B

2014-09-01

Stress develops when an organism requires additional metabolic resources to cope with demanding situations. This review will debate how recreational 3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy') can increase some aspects of acute and chronic stress in humans. Laboratory studies on the acute effects of MDMA on cortisol release and neurohormone levels in drug-free regular ecstasy/MDMA users have been reviewed, and the role of the hypothalamic-pituitary-adrenal (HPA) axis in chronic changes in anxiety, stress, and cognitive coping is debated. In the laboratory, acute ecstasy/MDMA use can increase cortisol levels by 100-200%, whereas ecstasy/MDMA-using dance clubbers experience an 800% increase in cortisol levels, because of the combined effects of the stimulant drug and dancing. Three-month hair samples of abstinent users revealed cortisol levels 400% higher than those in controls. Chronic users show heightened cortisol release in stressful environments and deficits in complex neurocognitive tasks. Event-related evoked response potential studies show altered patterns of brain activation, suggestive of increased mental effort, during basic information processing. Chronic mood deficits include more daily stress and higher depression in susceptible individuals. We conclude that ecstasy/MDMA increases cortisol levels acutely and subchronically and that changes in the HPA axis may explain why recreational ecstasy/MDMA users show various aspects of neuropsychobiological stress.

The multitasking framework: the effects of increasing workload on acute psychobiological stress reactivity.

PubMed

Wetherell, Mark A; Carter, Kirsty

2014-04-01

A variety of techniques exist for eliciting acute psychological stress in the laboratory; however, they vary in terms of their ease of use, reliability to elicit consistent responses and the extent to which they represent the stressors encountered in everyday life. There is, therefore, a need to develop simple laboratory techniques that reliably elicit psychobiological stress reactivity that are representative of the types of stressors encountered in everyday life. The multitasking framework is a performance-based, cognitively demanding stressor, representative of environments where individuals are required to attend and respond to several different stimuli simultaneously with varying levels of workload. Psychological (mood and perceived workload) and physiological (heart rate and blood pressure) stress reactivity was observed in response to a 15-min period of multitasking at different levels of workload intensity in a sample of 20 healthy participants. Multitasking stress elicited increases in heart rate and blood pressure, and increased workload intensity elicited dose-response increases in levels of perceived workload and mood. As individuals rarely attend to single tasks in real life, the multitasking framework provides an alternative technique for modelling acute stress and workload in the laboratory. Copyright © 2013 John Wiley & Sons, Ltd.

2017 GTO Project review Laboratory Evaluation of EGS Shear Stimulation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bauer, Stephen J.

The objectives and purpose of this research has been to produce laboratory-based experimental and numerical analyses to provide a physics-based understanding of shear stimulation phenomena (hydroshearing) and its evolution during stimulation. Water was flowed along fractures in hot and stressed fractured rock, to promote slip. The controlled laboratory experiments provide a high resolution/high quality data resource for evaluation of analysis methods developed by DOE to assess EGS “behavior” during this stimulation process. Segments of the experimental program will provide data sets for model input parameters, i.e., material properties, and other segments of the experimental program will represent small scale physicalmore » models of an EGS system, which may be modeled. The coupled lab/analysis project has been a study of the response of a fracture in hot, water-saturated fractured rock to shear stress experiencing fluid flow. Under this condition, the fracture experiences a combination of potential pore pressure changes and fracture surface cooling, resulting in slip along the fracture. The laboratory work provides a means to assess the role of “hydroshearing” on permeability enhancement in reservoir stimulation. Using the laboratory experiments and results to define boundary and input/output conditions of pore pressure, thermal stress, fracture shear deformation and fluid flow, and models were developed and simulations completed by the University of Oklahoma team. The analysis methods are ones used on field scale problems. The sophisticated numerical models developed contain parameters present in the field. The analysis results provide insight into the role of fracture slip on permeability enhancement-“hydroshear” is to be obtained. The work will provide valuable input data to evaluate stimulation models, thus helping design effective EGS.« less

A dose of nature: Tree cover, stress reduction, and gender differences

Treesearch

Bin Jiang; Chun-Yen Chang; William C. Sullivan

2014-01-01

Although it is well established that exposure to nearby nature can help reduce stress in individuals, the shape of the dose-response curve is entirely unclear. To establish this dose-response curve, we recruited 160 individuals for a laboratory experiment. Participants engaged in the Trier Social Stress Test (TSST) to induce psychological stress, and were then randomly...

Estimating Fault Friction From Seismic Signals in the Laboratory

DOE PAGES

Rouet-Leduc, Bertrand; Hulbert, Claudia; Bolton, David C.; ...

2018-01-29

Nearly all aspects of earthquake rupture are controlled by the friction along the fault that progressively increases with tectonic forcing but in general cannot be directly measured. We show that fault friction can be determined at any time, from the continuous seismic signal. In a classic laboratory experiment of repeating earthquakes, we find that the seismic signal follows a specific pattern with respect to fault friction, allowing us to determine the fault's position within its failure cycle. Using machine learning, we show that instantaneous statistical characteristics of the seismic signal are a fingerprint of the fault zone shear stress andmore » frictional state. Further analysis of this fingerprint leads to a simple equation of state quantitatively relating the seismic signal power and the friction on the fault. Finally, these results show that fault zone frictional characteristics and the state of stress in the surroundings of the fault can be inferred from seismic waves, at least in the laboratory.« less

Estimating Fault Friction From Seismic Signals in the Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rouet-Leduc, Bertrand; Hulbert, Claudia; Bolton, David C.

Nearly all aspects of earthquake rupture are controlled by the friction along the fault that progressively increases with tectonic forcing but in general cannot be directly measured. We show that fault friction can be determined at any time, from the continuous seismic signal. In a classic laboratory experiment of repeating earthquakes, we find that the seismic signal follows a specific pattern with respect to fault friction, allowing us to determine the fault's position within its failure cycle. Using machine learning, we show that instantaneous statistical characteristics of the seismic signal are a fingerprint of the fault zone shear stress andmore » frictional state. Further analysis of this fingerprint leads to a simple equation of state quantitatively relating the seismic signal power and the friction on the fault. Finally, these results show that fault zone frictional characteristics and the state of stress in the surroundings of the fault can be inferred from seismic waves, at least in the laboratory.« less

Estimating Fault Friction From Seismic Signals in the Laboratory

NASA Astrophysics Data System (ADS)

Rouet-Leduc, Bertrand; Hulbert, Claudia; Bolton, David C.; Ren, Christopher X.; Riviere, Jacques; Marone, Chris; Guyer, Robert A.; Johnson, Paul A.

2018-02-01

Nearly all aspects of earthquake rupture are controlled by the friction along the fault that progressively increases with tectonic forcing but in general cannot be directly measured. We show that fault friction can be determined at any time, from the continuous seismic signal. In a classic laboratory experiment of repeating earthquakes, we find that the seismic signal follows a specific pattern with respect to fault friction, allowing us to determine the fault's position within its failure cycle. Using machine learning, we show that instantaneous statistical characteristics of the seismic signal are a fingerprint of the fault zone shear stress and frictional state. Further analysis of this fingerprint leads to a simple equation of state quantitatively relating the seismic signal power and the friction on the fault. These results show that fault zone frictional characteristics and the state of stress in the surroundings of the fault can be inferred from seismic waves, at least in the laboratory.

Investigating the pathogenesis of posttraumatic stress disorder with neuroimaging.

PubMed

Pitman, R K; Shin, L M; Rauch, S L

2001-01-01

Rapidly evolving brain neuroimaging techniques such as magnetic resonance imaging (MRI) and positron emission tomography (PET) are proving fruitful in exploring the pathogenesis and pathophysiology of posttraumatic stress disorder (PTSD). Structural abnormalities in PTSD found with MRI include nonspecific white matter lesions and decreased hippocampal volume. These abnormalities may reflect pretrauma vulnerability to develop PTSD, or they may be a consequence of traumatic exposure, PTSD, and/or PTSD sequelae. Functional neuroimaging symptom provocation and cognitive activation paradigms using PET measurement of regional cerebral blood flow have revealed greater activation of the amygdala and anterior paralimbic structures (which are known to be involved in processing negative emotions such as fear), greater deactivation of Broca's region (motor speech) and other nonlimbic cortical regions, and failure of activation of the cingulate cortex (which possibly plays an inhibitory role) in response to trauma-related stimuli in individuals with PTSD. Functional MRI research has shown the amygdala to be hyperresponsive to fear-related stimuli in this disorder. Research with PET suggests that cortical, notably hippocampal, metabolism is suppressed to a greater extent by pharmacologic stimulation of the noradrenergic system in persons with PTSD. The growth of knowledge concerning the anatomical and neurochemical basis of this important mental disorder will hopefully eventually lead to rational psychological and pharmacologic treatments.

Lewis Researcher in the Materials and Stresses Building

NASA Image and Video Library

1952-12-21

A materials researcher at the NACA’s Lewis Flight Propulsion Laboratory examines a surface crack detection apparatus in the Materials and Stresses Building during December 1952. Materials research was an important aspect of propulsion technology. Advanced engine systems relied upon alloys, and later composites, that were strong, lightweight, and impervious to high temperatures. Jet engines which became increasingly popular in the late 1940s, produced much higher temperatures than piston engines. These higher temperatures stressed engine components, particularly turbines. Although Lewis materials research began during World War II, the Materials and Thermodynamics Division was not created until 1949. Its primary laboratories were located in the Materials and Stresses Building. The group sought to create new, improved materials and to improve engine design through increased understanding of materials. The Lewis materials researchers of the 1950s made contributions to nickel-aluminum alloys, cermet blades, metal matrix composites, oxide dispersion strengthened superalloys, and universal slopes.

P3 and provoked aggressive behavior.

PubMed

Fanning, Jennifer R; Berman, Mitchell E; Long, James M

2014-01-01

Cognitive and biological processes play a role in human aggression. However, relatively little is known about the neural correlates of cognitive processes in aggressive individuals, particularly as they unfold during an aggressive encounter. We investigated whether the P3 event-related potential (ERP) discriminates aggressive versus nonaggressive individuals during a provocative, aggressive encounter. Forty-eight participants (23 men and 25 women) were classified as aggressive or nonaggressive based on self-reported life history of aggression. Aggressive behavior was assessed using a modification of a well-validated laboratory task during which the participant and a fictitious opponent ostensibly delivered and received noise blasts of low, medium, and high intensity. Provocation was manipulated by altering the level of noise set by the opponent. Aggression was defined as the number of high-intensity noise blasts the participant set for the opponent. As predicted, P3 amplitude in response to provocation differed as a function of aggressive history. Nonaggressive individuals showed enhanced P3 when provoked by the opponent relative to low provocation, but this effect was absent in aggressive individuals. The results suggest that aggressive individuals engage fewer neural processing resources in response to provoking social cues, which may reflect aberrant cognitive and emotional processes.

Phytoplankton Productivity numerical model: calibration via laboratory cultures

NASA Astrophysics Data System (ADS)

Zavatarelli, Marco; fiori, Emanuela; Carolina, Amadio

2017-04-01

The primary production module of the "Biogeochemical Flux Model" (BFM) has been used to replicate results from laboratory phytoplankton cultures of diatoms, dinoflagellates and picophytoplankton. The model explicitly solve for the phytoplankton, chlorophyll, carbon, phosphorus, nitrogen and (diatoms only) silicon content. Simulations of the temporal evolution of the cultured phytoplankton biomass, have been carried out in order to provide a correct parameterization of the temperature role in modulating the growth dynamics, and to gain insight in the process of chlorophyll turnover, with particular reference to the phytoplankton biomass decay in condition of nutrient stress. Results highligthed some limitation of the Q10 approach in defining the temperature constraints on the primary production (particularly at relatively high temperature) This required a modification of such approach. Moreover, the decay of the chlorophyll concentration under nutrient stress, appeared (as expected) significantly decoupled from the evolution of the carbon content. The implementation of a specific procedure (based on the laboratory culture results) adressing such decoupling, allowed for the achievement of better agreement between model and observations.

Exploring the use of thermal infrared imaging in human stress research.

PubMed

Engert, Veronika; Merla, Arcangelo; Grant, Joshua A; Cardone, Daniela; Tusche, Anita; Singer, Tania

2014-01-01

High resolution thermal infrared imaging is a pioneering method giving indices of sympathetic activity via the contact-free recording of facial tissues (thermal imprints). Compared to established stress markers, the great advantage of this method is its non-invasiveness. The goal of our study was to pilot the use of thermal infrared imaging in the classical setting of human stress research. Thermal imprints were compared to established stress markers (heart rate, heart rate variability, finger temperature, alpha-amylase and cortisol) in 15 participants undergoing anticipation, stress and recovery phases of two laboratory stress tests, the Cold Pressor Test and the Trier Social Stress Test. The majority of the thermal imprints proved to be change-sensitive in both tests. While correlations between the thermal imprints and established stress markers were mostly non-significant, the thermal imprints (but not the established stress makers) did correlate with stress-induced mood changes. Multivariate pattern analysis revealed that in contrast to the established stress markers the thermal imprints could not disambiguate anticipation, stress and recovery phases of both tests. Overall, these results suggest that thermal infrared imaging is a valuable method for the estimation of sympathetic activity in the stress laboratory setting. The use of this non-invasive method may be particularly beneficial for covert recordings, in the study of special populations showing difficulties in complying with the standard instruments of data collection and in the domain of psychophysiological covariance research. Meanwhile, the established stress markers seem to be superior when it comes to the characterization of complex physiological states during the different phases of the stress cycle.

Aspirin provocation increases 8-iso-PGE2 in exhaled breath condensate of aspirin-hypersensitive asthmatics.

PubMed

Mastalerz, Lucyna; Januszek, Rafał; Kaszuba, Marek; Wójcik, Krzysztof; Celejewska-Wójcik, Natalia; Gielicz, Anna; Plutecka, Hanna; Oleś, Krzysztof; Stręk, Paweł; Sanak, Marek

2015-09-01

Isoprostanes are bioactive compounds formed by non-enzymatic oxidation of polyunsaturated fatty acids, mostly arachidonic, and markers of free radical generation during inflammation. In aspirin exacerbated respiratory disease (AERD), asthmatic symptoms are precipitated by ingestion of non-steroid anti-inflammatory drugs capable for pharmacologic inhibition of cyclooxygenase-1 isoenzyme. We investigated whether aspirin-provoked bronchoconstriction is accompanied by changes of isoprostanes in exhaled breath condensate (EBC). EBC was collected from 28 AERD subjects and 25 aspirin-tolerant asthmatics before and after inhalatory aspirin challenge. Concentrations of 8-iso-PGF2α, 8-iso-PGE2, and prostaglandin E2 were measured using gas chromatography/mass spectrometry. Leukotriene E4 was measured by immunoassay in urine samples collected before and after the challenge. Before the challenge, exhaled 8-iso-PGF2α, 8-iso-PGE2, and PGE2 levels did not differ between the study groups. 8-iso-PGE2 level increased in AERD group only (p=0.014) as a result of the aspirin challenge. Urinary LTE4 was elevated in AERD, both in baseline and post-challenge samples. Post-challenge airways 8-iso-PGE2 correlated positively with urinary LTE4 level (p=0.046), whereas it correlated negatively with the provocative dose of aspirin (p=0.027). A significant increase of exhaled 8-iso-PGE2 after inhalatory challenge with aspirin was selective and not present for the other isoprostane measured. This is a novel finding in AERD, suggesting that inhibition of cyclooxygenase may elicit 8-iso-PGE2 production in a specific mechanism, contributing to bronchoconstriction and systemic overproduction of cysteinyl leukotrienes. Copyright © 2015 Elsevier Inc. All rights reserved.

Epigenetic Influence of Stress and the Social Environment

PubMed Central

Gudsnuk, Kathryn; Champagne, Frances A.

2012-01-01

Animal models of early-life stress and variation in social experience across the lifespan have contributed significantly to our understanding of the environmental regulation of the developing brain. Plasticity in neurobiological pathways regulating stress responsivity, cognition, and reproductive behavior is apparent during the prenatal period and continues into adulthood, suggesting a lifelong sensitivity to environmental cues. Recent evidence suggests that dynamic epigenetic changes—molecular modifications that alter gene expression without altering the underlying DNA sequence—account for this plasticity. In this review, we highlight studies of laboratory rodents that illustrate the association between the experience of prenatal stress, maternal separation, maternal care, abusive caregiving in infancy, juvenile social housing, and adult social stress and variation in DNA methylation and histone modification. Moreover, we discuss emerging evidence for the transgenerational impact of these experiences. These experimental paradigms have yielded insights into the potential role of epigenetic mechanisms in mediating the effects of the environment on human development and also indicate that consideration of the sensitivity of laboratory animals to environmental cues may be an important factor in predicting long-term health and welfare. PMID:23744967

Consequences of keeping Mytilus in the laboratory as assessed by different cellular condition indices

NASA Astrophysics Data System (ADS)

Cajaraville, M. P.; Díez, G.; Marigómez, I. A.; Angulo, E.

1991-12-01

Mytilus galloprovincialis Lmk. were maintained in the laboratory for three months in a semicontinuous water flow system. Animals were fed a commercial filter-feeder food and sampled after 0, 21, 35, 49, 77, and 91 days. In order to establish whether laboratory conditions and the food used were deleterious to mussels, their health status was assessed by quantifying different histological parameters of the digestive gland tissue. It was concluded that mussels kept for more than 35 days under the described laboratory conditions showed signs of stress presumably caused by the reproductive state of the mussels investigated. The food used and the nutrition-related health status of the animals were adequate, as shown by transmission electron microscopical studies after the 91-day maintenance period. A stress response was also evoked by a 10-day starvation period, which was reflected by an increased proportion of type I and type IV digestive tubules, and a reduced “Mean Epithelial Thickness” (MET). Finally, the results demonstrate the sensitivity of quantitative histological diagnosis in comparison to subjective tubule grading procedures in the assessment of the degree of stress experienced by mussels.

Reconsolidation of Crushed Salt to 250°C Under Hydrostatic and Shear Stress Conditions Scott Broome, Frank Hansen, and SJ Bauer Sandia National Laboratories, Geomechanics Department

NASA Astrophysics Data System (ADS)

Broome, S. T.

2012-12-01

�. At predetermined differential stress levels the stress is held constant and the salt consolidates. Displacement gages mounted on the samples show little lateral deformation until the samples reach a porosity of ~10%. Interestingly, vapor is vented in tests at 250°C and condenses at the vent port. Release of water is not observed in the lower two test temperatures. It is hypothesized that the water originates from fluid inclusions, which were made accessible by intragranular deformational processes including decrepitation. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Experimental Measurement of In Situ Stress

NASA Astrophysics Data System (ADS)

Tibbo, Maria; Milkereit, Bernd; Nasseri, Farzine; Schmitt, Douglas; Young, Paul

2016-04-01

The World Stress Map data is determined by stress indicators including earthquake focal mechanisms, in situ measurement in mining, oil and gas boreholes as well as the borehole cores, and geologic data. Unfortunately, these measurements are not only infrequent but sometimes infeasible, and do not provide nearly enough data points with high accuracy to correctly infer stress fields in deep mines around the world. Improvements in stress measurements of Earth's crust is fundamental to several industries such as oil and gas, mining, nuclear waste management, and enhanced geothermal systems. Quantifying the state of stress and the geophysical properties of different rock types is a major complication in geophysical monitoring of deep mines. Most stress measurement techniques involve either the boreholes or their cores, however these measurements usually only give stress along one axis, not the complete stress tensor. The goal of this project is to investigate a new method of acquiring a complete stress tensor of the in situ stress in the Earth's crust. This project is part of a comprehensive, exploration geophysical study in a deep, highly stressed mine located in Sudbury, Ontario, Canada, and focuses on two boreholes located in this mine. These boreholes are approximately 400 m long with NQ diameters and are located at depths of about 1300 - 1600 m and 1700 - 2000 m. Two borehole logging surveys were performed on both boreholes, October 2013 and July 2015, in order to perform a time-lapse analysis of the geophysical changes in the mine. These multi-parameter surveys include caliper, full waveform sonic, televiewer, chargeability (IP), and resistivity. Laboratory experiments have been performed on borehole core samples of varying geologies from each borehole. These experiments have measured the geophysical properties including elastic modulus, bulk modulus, P- and S-wave velocities, and density. The apparatus' used for this project are geophysical imaging cells capable

Stress Optical Coefficient, Test Methodology, and Glass Standard Evaluation

DTIC Science & Technology

2016-05-01

identifying and mapping flaw size distributions on glass surfaces for predicting mechanical response. International Journal of Applied Glass ...ARL-TN-0756 ● MAY 2016 US Army Research Laboratory Stress Optical Coefficient, Test Methodology, and Glass Standard Evaluation...Stress Optical Coefficient, Test Methodology, and Glass Standard Evaluation by Clayton M Weiss Oak Ridge Institute for Science and Education

Study of occupational stress among railway engine pilots

PubMed Central

Kumar, Devesh; Singh, Jai Vir; Kharwar, Poonam S.

2011-01-01

Background: Traffic volume and speed is going to be increased in Indian Railways successively, leading to higher stress in staff connected with train operations. The jobs of railway engine pilots come under the category of high-strain jobs, necessitating a need to conduct multicentric study to unfold the factors associated with occupational stress and organizational strategies. Materials and Methods: Present study covered 185 railway engine pilots and office clerks working in various railway zones by incidental method. Occupational Stress Index (OSI) test developed by Srivastva and Singh, questionnaire of specific stressors constructed by authors and laboratory test battery for psychological screening of high-speed train pilots were used as tools. Results: Means of OSI and all the 12 occupational stressors of railway engine pilots were found significantly higher to that of office clerks. Means of OSI and occupational stressors of goods train pilots were significantly higher in comparison to high-speed train pilots and passenger train pilots. Study revealed positive correlation of speed perception and complex reaction time tests and negative correlation of other constituent tests of laboratory test battery to OSI test. Highest subgroup of stressor observedwas role overload followed by role conflict. Conclusions: These findings provide a prima facie evidence of higher occupational stress among railway engine pilots because of identified specific stressors prevalent in their job and explore the possible intervention strategies for its reduction. Significant correlation is noticed between OSI and laboratory test results, indicating its relevant utility in preliminary psychological screening. PMID:21808497

Does the arrival index predict physiological stress reactivity in children.

PubMed

de Veld, Danielle M J; Riksen-Walraven, J Marianne; de Weerth, Carolina

2014-09-01

Knowledge about children's stress reactivity and its correlates is mostly based on one stress task, making it hard to assess the generalizability of the results. The development of an additional stress paradigm for children, that also limits stress exposure and test time, could greatly advance this field of research. Research in adults may provide a starting point for the development of such an additional stress paradigm, as changes in salivary cortisol and alpha-amylase (sAA) over a 1-h pre-stress period in the laboratory correlated strongly with subsequent reactivity to stress task (Balodis et al., 2010, Psychoneuroendocrinology 35:1363-73). The present study examined whether such strong correlations could be replicated in 9- to 11-year-old children. Cortisol and sAA samples were collected from 158 children (83 girls) during a 2.5-h visit to the laboratory. This visit included a 1-h pre-stress period in which children performed some non-stressful tasks and relaxed before taking part in a psychosocial stress task (TSST-C). A higher cortisol arrival index was significantly and weakly correlated with a higher AUCg but unrelated to cortisol reactivity to the stressor. A higher sAA arrival index was significantly and moderately related to lower stress reactivity and to a lower AUCi. Children's personality and emotion regulation variables were unrelated to the cortisol and sAA arrival indices. The results of this study do not provide a basis for the development of an additional stress paradigm for children. Further replications in children and adults are needed to clarify the potential meaning of an arrival index.

A pilot study on the validity of using pictures and videos for individualized symptom provocation in obsessive-compulsive disorder.

PubMed

Simon, Daniela; Kischkel, Eva; Spielberg, Rüdiger; Kathmann, Norbert

2012-06-30

Distressing symptom-related anxiety is difficult to study in obsessive-compulsive disorder (OCD) due to the disorder's heterogeneity. Our aim was to develop and validate a set of pictures and films comprising a variety of prominent OCD triggers that can be used for individually tailored symptom provocation in experimental studies. In a two-staged production procedure a large pool of OCD triggers and neutral contents was produced and preselected by three psychotherapists specialized in OCD. A sample of 13 OCD patients and 13 controls rated their anxiety, aversiveness and arousal during exposure to OCD-relevant, aversive and neutral control stimuli. Our findings demonstrate differences between the responses of patients and controls to OCD triggers only. Symptom-related anxiety was stronger in response to dynamic compared with static OCD-relevant stimuli. Due to the small number of 13 patients included in the study, only tentative conclusions can be drawn and this study merely provides a first step of validation. These standardized sets constitute valuable tools that can be used in experimental studies on the brain correlates of OCD symptoms and for the study of therapeutic interventions in order to contribute to future developments in the field. Copyright © 2012 Elsevier Ltd. All rights reserved.

A Collaborative, Investigative Recombinant DNA Technology Course with Laboratory

ERIC Educational Resources Information Center

Pezzementi, Leo; Johnson, Joy F.

2002-01-01

A recombinant DNA technology course was designed to promote contextual, collaborative, inquiry-based learning of science where students learn from one another and have a sense of ownership of their education. The class stressed group presentations and critical reading and discussion of scientific articles. The laboratory consisted of two research…

Learning of Musculoskeletal Ligament Stress Testing in a Gross Anatomy Laboratory

ERIC Educational Resources Information Center

Krause, David A.; Youdas, James W.; Hollman, John H.

2011-01-01

Human anatomy in physical therapy programs is a basic science course serving as a foundation for subsequent clinical courses. Integration of anatomy with a clinical emphasis throughout a curriculum provides opportunities for reinforcement of previously learned material. Considering the human cadaver laboratory as a fixed cost to our program, we…

Standards, Regulation and Registration of Dental Laboratories. An Industry Update.

PubMed

Giovannone, Paul L

2015-01-01

State dental associations are showing increased interest in maintaining current standards and regulations affecting the dental laboratory industry as mandated by the Food and Drug Administration. The domestic dental laboratory industry is being significantly stressed by foreign competition, rapid technology development and unprecedented consolidation, which are changing the way that prosthetic devices and restorations are manufactured and delivered to dentists. Of paramount importance to the prescribing dentist is the accurate documentation of the source and materials being used in prostheses being delivered to patients.

Anatomical and functional overlap within the insula and anterior cingulate cortex during interoception and phobic symptom provocation.

PubMed

Caseras, Xavier; Murphy, Kevin; Mataix-Cols, David; López-Solà, Marina; Soriano-Mas, Carles; Ortriz, Hector; Pujol, Jesus; Torrubia, Rafael

2013-05-01

The anterior insula and the dorsal anterior cingulate cortex (ACC) are regarded as key brain structures associated with the integration of perceived phobic characteristics of external stimuli and the perception of ones own body responses that leads to emotional feelings. To test to what extent the activity in these two brain structures anatomically and functionally overlap during phobic reactions and interoception, we submitted the same group of phobic participants (n = 29; either spider or blood-injection-injury (BII) phobics) and controls (n = 17) to both type of experimental paradigms. Results showed that there was a clear anatomical overlap in the Blood Oxygen Level-Dependent (BOLD) responses within the anterior insula and ACC elicited during phobic symptom provocation and during interoceptive awareness. The activity within these two brain structures also showed to be correlated in the spider phobia group, but not in the BII phobic participants. Our results seem to support the idea that the activity within these two brain areas would be associated with the integration of perceived stimuli characteristics and bodily responses that lead to what we label as "fear." However, that seems not to be the case in BII phobia, where more research is needed in order to clarify to what extent that could be associated with the idiosyncratic physiological response that these patients present in front of phobic stimuli (i.e., drop in heart rate and blood pressure). Copyright © 2011 Wiley Periodicals, Inc.

Comparison of Valsalva Maneuver, Amyl Nitrite, and Exercise Echocardiography to Demonstrate Latent Left Ventricular Outflow Obstruction in Hypertrophic Cardiomyopathy.

PubMed

Ayoub, Chadi; Geske, Jeffrey B; Larsen, Carolyn M; Scott, Christopher G; Klarich, Kyle W; Pellikka, Patricia A

2017-12-15

Guidelines recommend exercise stress echocardiogram (ESE) for patients with hypertrophic cardiomyopathy (HC) if a 50 mm Hg gradient is not present at rest or provoked with Valsalva or amyl nitrite, to direct medical and surgical management. However, no study has directly compared all 3 methods. We sought to evaluate efficacy and degree of provocation of left ventricular outflow gradients by ESE, and compare with Valsalva and amyl nitrite. In patients with HC between 2002 and 2015, resting echocardiograms and ESEs within 1 year were retrospectively reviewed. Gradients elicited by each provocation method were compared. Rest and ESE were available in 97 patients (mean age 54 ± 18 years, 57% male); 78 underwent Valsalva maneuver and 41 amyl nitrite provocation. Median gradients (interquartile range) were 10 mm Hg (7,19) at rest, 16 mm Hg (9,34) with Valsalva, 23 mm Hg (13,49) with amyl nitrite, and 26 mm Hg (13,58) with ESE. ESE and amyl nitrite were able to provoke obstruction (≥30 mm Hg) and severe obstruction (≥50 mm Hg) more frequently than Valsalva. In patients with resting gradient <30 mm Hg (n = 83), provocation maneuvers demonstrated dynamic obstruction in 51%; in those with Valsalva gradient <30 mm Hg (n = 57), ESE or amyl nitrite provoked a gradient in 44%; and in those with amyl nitrite gradient <30 mm Hg (n = 20), ESE provoked a gradient in 29%. No demographic or baseline echocardiographic parameter predicted provocable obstruction. In conclusion, ESE is clinically useful; however, different provocation maneuvers may be effective in different patients with HC, and all maneuvers may be required to provoke dynamic obstruction in symptomatic patients. Copyright © 2017 Elsevier Inc. All rights reserved.

Stress Sensitivity and Stress Generation in Social Anxiety Disorder: A Temporal Process Approach

PubMed Central

Farmer, Antonina S.; Kashdan, Todd B.

2015-01-01

Dominant theoretical models of social anxiety disorder (SAD) suggest that people who suffer from function-impairing social fears are likely to react more strongly to social stressors. Researchers have examined the reactivity of people with SAD to stressful laboratory tasks, but there is little knowledge about how stress affects their daily lives. We asked 79 adults from the community, 40 diagnosed with SAD and 39 matched healthy controls, to self-monitor their social interactions, social events, and emotional experiences over two weeks using electronic diaries. These data allowed us to examine associations of social events and emotional well-being both within-day and from one day to the next. Using hierarchical linear modeling, we found all participants to report increases in negative affect and decreases in positive affect and self-esteem on days when they experienced more stressful social events. However, people with SAD displayed greater stress sensitivity, particularly in negative emotion reactions to stressful social events, compared to healthy controls. Groups also differed in how previous days’ events influenced sensitivity to current days’ events. Moreover, we found evidence of stress generation in that the SAD group reported more frequent interpersonal stress, though temporal analyses did not suggest greater likelihood of social stress on days following intense negative emotions. Our findings support the role of heightened social stress sensitivity in SAD, highlighting rigidity in reactions and occurrence of stressful experiences from one day to the next. These findings also shed light on theoretical models of emotions and self-esteem in SAD and present important clinical implications. PMID:25688437

Exploring the Use of Thermal Infrared Imaging in Human Stress Research

PubMed Central

Grant, Joshua A.; Cardone, Daniela; Tusche, Anita; Singer, Tania

2014-01-01

High resolution thermal infrared imaging is a pioneering method giving indices of sympathetic activity via the contact-free recording of facial tissues (thermal imprints). Compared to established stress markers, the great advantage of this method is its non-invasiveness. The goal of our study was to pilot the use of thermal infrared imaging in the classical setting of human stress research. Thermal imprints were compared to established stress markers (heart rate, heart rate variability, finger temperature, alpha-amylase and cortisol) in 15 participants undergoing anticipation, stress and recovery phases of two laboratory stress tests, the Cold Pressor Test and the Trier Social Stress Test. The majority of the thermal imprints proved to be change-sensitive in both tests. While correlations between the thermal imprints and established stress markers were mostly non-significant, the thermal imprints (but not the established stress makers) did correlate with stress-induced mood changes. Multivariate pattern analysis revealed that in contrast to the established stress markers the thermal imprints could not disambiguate anticipation, stress and recovery phases of both tests. Overall, these results suggest that thermal infrared imaging is a valuable method for the estimation of sympathetic activity in the stress laboratory setting. The use of this non-invasive method may be particularly beneficial for covert recordings, in the study of special populations showing difficulties in complying with the standard instruments of data collection and in the domain of psychophysiological covariance research. Meanwhile, the established stress markers seem to be superior when it comes to the characterization of complex physiological states during the different phases of the stress cycle. PMID:24675709

Physiological adaptation to recurrent social stress of extraversion.

PubMed

Lu, Wei; Wang, Zhenhong

2017-02-01

The present studies examined the influence of extraversion on physiological reactivity, recovery, and physiological habituation-sensitization to repeated social stressors. In Study 1, subjective and physiological data were collected from 97 college students who were categorized as high (n = 51) and low (n = 46) on extraversion (NEO-FFI) across five laboratory stages: baseline, stress 1, poststress 1, stress 2, and poststress 2. Results indicated high extraversion (HE) participants exhibited relative lesser heart rate (HR) reactivity and respiratory sinus arrhythmia (RSA) withdrawals to, and more complete HR and RSA recovery after the first social stress, and also exhibited relative lesser HR reactivity to the second social stress. When repeatedly exposed to a social stressor, HE participants showed pronounced systolic blood pressure (SBP) adaptation, low extraversion (LE) participants displayed diastolic blood pressure (DBP) sensitization. In Study 2, data were collected from another 78 participants (HE: n = 40, LE: n = 38) across the same laboratory stages with speech performance videotaped. After controlling for the speech styles, Study 2 found the same HR response and SBP/DBP adaptation pattern across extraversion groups to social stress as Study 1 but not RSA reactivity. These findings suggest extraverts exhibit more adaptive physiological reactivity to recurrent social stressors, which thus might benefit their health. © 2016 Society for Psychophysiological Research.

MSU-DOE Plant Research Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1991-01-01

This document is the compiled progress reports of research funded through the Michigan State University/Department of Energy Plant Research Laboratory. Fourteen reports are included, covering the molecular basis of plant/microbe symbiosis, cell wall biosynthesis and proteins, gene expression, stress responses, plant hormone biosynthesis, interactions between the nuclear and organelle genomes, sensory transduction and tropisms, intracellular sorting and trafficking, regulation of lipid metabolism, molecular basis of disease resistance and plant pathogenesis, developmental biology of Cyanobacteria, and hormonal involvement in environmental control of plant growth. 320 refs., 26 figs., 3 tabs. (MHB)

Attitudes of medical laboratory technology graduates towards the internship training period at king faisal university.

PubMed

Bashawri, Layla A M; Ahmed, Mirghani A; Bahnassy, Ahmed A L; Al-Salim, Jawaher A

2006-05-01

The objective of this present survey was to look into the attitudes of medical laboratory technology (MLT) graduates towards the internship training period of the MLT Department, College of Applied Medical Sciences, King Faisal University. A self-administered questionnaire was designed and distributed for this purpose. The study period was from December 1(st) 2002 - 31(st) December 2004. Two-hundred questionnaires were distributed to recent graduates, and 115 were returned completed. All respondents agreed with the importance and necessity of the internship period, and felt it should not be reduced or eliminated. The most favorite laboratory where they liked to work was microbiology (70%). They all agreed that evaluation report with hospital staff and laboratory set up were vital in achieving the goals of the internship period. The majority stressed the significance of safety precautions and the application of theoretical knowledge before performing technical assignments. The respondents had very positive attitudes towards the internship-training period stressing its importance. The most favorite laboratory rotations were in rank order: Microbiology, Serology followed by Histotechnology, Hematology, Blood Banking and finally Clinical Chemistry. The majority of graduates had a very positive attitude also towards medical laboratory technology as a profession.

PCI fuel failure analysis: a report on a cooperative program undertaken by Pacific Northwest Laboratory and Chalk River Nuclear Laboratories.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohr, C.L.; Pankaskie, P.J.; Heasler, P.G.

Reactor fuel failure data sets in the form of initial power (P/sub i/), final power (P/sub f/), transient increase in power (..delta..P), and burnup (Bu) were obtained for pressurized heavy water reactors (PHWRs), boiling water reactors (BWRs), and pressurized water reactors (PWRs). These data sets were evaluated and used as the basis for developing two predictive fuel failure models, a graphical concept called the PCI-OGRAM, and a nonlinear regression based model called PROFIT. The PCI-OGRAM is an extension of the FUELOGRAM developed by AECL. It is based on a critical threshold concept for stress dependent stress corrosion cracking. The PROFITmore » model, developed at Pacific Northwest Laboratory, is the result of applying standard statistical regression methods to the available PCI fuel failure data and an analysis of the environmental and strain rate dependent stress-strain properties of the Zircaloy cladding.« less

Anxiety, Anxiety Sensitivity, and Perceived Stress as Predictors of Recent Drinking, Alcohol Craving, and Social Stress Response in Heavy Drinkers.

PubMed

McCaul, Mary E; Hutton, Heidi E; Stephens, Mary Ann C; Xu, Xiaoqiang; Wand, Gary S

2017-04-01

Stress and anxiety are widely considered to be causally related to alcohol craving and consumption, as well as development and maintenance of alcohol use disorder (AUD). However, numerous preclinical and human studies examining effects of stress or anxiety on alcohol use and alcohol-related problems have been equivocal. This study examined relationships between scores on self-report anxiety, anxiety sensitivity, and stress measures and frequency and intensity of recent drinking, alcohol craving during early withdrawal, as well as laboratory measures of alcohol craving and stress reactivity among heavy drinkers with AUD. Media-recruited, heavy drinkers with AUD (N = 87) were assessed for recent alcohol consumption. Anxiety and stress levels were characterized using paper-and-pencil measures, including the Beck Anxiety Inventory (BAI), the Anxiety Sensitivity Index-3 (ASI-3), and the Perceived Stress Scale (PSS). Eligible subjects (N = 30) underwent alcohol abstinence on the Clinical Research Unit; twice daily measures of alcohol craving were collected. On day 4, subjects participated in the Trier Social Stress Test; measures of cortisol and alcohol craving were collected. In multivariate analyses, higher BAI scores were associated with lower drinking frequency and reduced drinks/drinking day; in contrast, higher ASI-3 scores were associated with higher drinking frequency. BAI anxiety symptom and ASI-3 scores also were positively related to Alcohol Use Disorders Identification Test total scores and AUD symptom and problem subscale measures. Higher BAI and ASI-3 scores but not PSS scores were related to greater self-reported alcohol craving during early alcohol abstinence. Finally, BAI scores were positively related to laboratory stress-induced cortisol and alcohol craving. In contrast, the PSS showed no relationship with most measures of alcohol craving or stress reactivity. Overall, clinically oriented measures of anxiety compared with perceived stress were more

A translational investigation targeting stress-reactivity and prefrontal cognitive control with guanfacine for smoking cessation.

PubMed

McKee, Sherry A; Potenza, Marc N; Kober, Hedy; Sofuoglu, Mehmet; Arnsten, Amy F T; Picciotto, Marina R; Weinberger, Andrea H; Ashare, Rebecca; Sinha, Rajita

2015-03-01

Stress and prefrontal cognitive dysfunction have key roles in driving smoking; however, there are no therapeutics for smoking cessation that attenuate the effects of stress on smoking and enhance cognition. Central noradrenergic pathways are involved in stress-induced reinstatement to nicotine and in the prefrontal executive control of adaptive behaviors. We used a novel translational approach employing a validated laboratory analogue of stress-precipitated smoking, functional magnetic resonance imaging (fMRI), and a proof-of-concept treatment period to evaluate whether the noradrenergic α2a agonist guanfacine (3 mg/day) versus placebo (0 mg/day) reduced stress-precipitated smoking in the laboratory, altered cortico-striatal activation during the Stroop cognitive-control task, and reduced smoking following a quit attempt. In nicotine-deprived smokers (n=33), stress versus a neutral condition significantly decreased the latency to smoke, and increased tobacco craving, ad-libitum smoking, and systolic blood pressure in placebo-treated subjects, and these effects were absent or reduced in guanfacine-treated subjects. Following stress, placebo-treated subjects demonstrated decreased cortisol levels whereas guanfacine-treated subjects demonstrated increased levels. Guanfacine, compared with placebo, altered prefrontal activity during a cognitive-control task, and reduced cigarette use but did not increase complete abstinence during treatment. These preliminary laboratory, neuroimaging, and clinical outcome data were consistent and complementary and support further development of guanfacine for smoking cessation. © The Author(s) 2014.

Methodology for calculating shear stress in a meandering channel

Treesearch

Kyung-Seop Sin

2010-01-01

Shear stress in meandering channels is the key parameter to predict bank erosion and bend migration. A representative study reach of the Rio Grande River in central New Mexico has been modeled in the Hydraulics Laboratory at CSU. To determine the shear stress distribution in a meandering channel, the large scale (1:12) physical modeling study was conducted in the...

Stress and the Kidney

PubMed Central

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

2016-01-01

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

Comparison of myocardial ischemia during intense mental stress using flight simulation in airline pilots with coronary artery disease to that produced with conventional mental and treadmill exercise stress testing.

PubMed

Doorey, Andrew; Denenberg, Barry; Sagar, Vidya; Hanna, Tracy; Newman, Jack; Stone, Peter H

2011-09-01

Mental stress increases cardiovascular morbidity and mortality. Although laboratory mental stress often causes less myocardial ischemia than exercise stress (ES), it is unclear whether mental stress is intrinsically different or differences are due to less hemodynamic stress with mental stress. We sought to evaluate the hemodynamic and ischemic response to intense realistic mental stress created by modern flight simulators and compare this response to that of exercise treadmill testing and conventional laboratory mental stress (CMS) testing in pilots with coronary disease. Sixteen airline pilots with angiographically documented coronary disease and documented myocardial ischemia during ES were studied using maximal treadmill ES, CMS, and aviation mental stress (AMS) testing. AMS testing was done in a sophisticated simulator using multiple system failures as stressors. Treadmill ES testing resulted in the highest heart rate, but AMS caused a higher blood pressure response than CMS. Maximal rate-pressure product was not significantly different between ES and AMS (25,646 vs 23,347, p = 0.08), although these were higher than CMS (16,336, p <0.0001). Despite similar hemodynamic stress induced by ES and AMS, AMS resulted in significantly less ST-segment depression and nuclear ischemia than ES. Differences in induction of ischemia by mental stress compared to ES do not appear to be due to the creation of less hemodynamic stress. In conclusion, even with equivalent hemodynamic stress, intense realistic mental stress induced by flight simulators results in significantly less myocardial ischemia than ES as measured by ST-segment depression and nuclear ischemia. Copyright © 2011 Elsevier Inc. All rights reserved.

Large Parachute for NASA Mars Science Laboratory

NASA Image and Video Library

2009-04-22

The parachute for NASA Mars Science Laboratory mission opens to a diameter of nearly 16 meters 51 feet. This image shows a duplicate qualification-test parachute inside the world's largest wind tunnel, at NASA Ames Research Center, Moffett Field, Calif. The Mars Science Laboratory will be launched in 2011 for a landing on Mars in 2012. Its parachute is the largest ever built to fly on an extraterrestrial mission. The parachute uses a configuration called disk-gap-band, with 80 suspension lines. Most of the orange and white fabric is nylon, though a small disk of heavier polyester is used near the vent in the apex of the canopy due to higher stresses there. http://photojournal.jpl.nasa.gov/catalog/PIA11994

Adaptive laboratory evolution -- principles and applications for biotechnology.

PubMed

Dragosits, Martin; Mattanovich, Diethard

2013-07-01

Adaptive laboratory evolution is a frequent method in biological studies to gain insights into the basic mechanisms of molecular evolution and adaptive changes that accumulate in microbial populations during long term selection under specified growth conditions. Although regularly performed for more than 25 years, the advent of transcript and cheap next-generation sequencing technologies has resulted in many recent studies, which successfully applied this technique in order to engineer microbial cells for biotechnological applications. Adaptive laboratory evolution has some major benefits as compared with classical genetic engineering but also some inherent limitations. However, recent studies show how some of the limitations may be overcome in order to successfully incorporate adaptive laboratory evolution in microbial cell factory design. Over the last two decades important insights into nutrient and stress metabolism of relevant model species were acquired, whereas some other aspects such as niche-specific differences of non-conventional cell factories are not completely understood. Altogether the current status and its future perspectives highlight the importance and potential of adaptive laboratory evolution as approach in biotechnological engineering.

Better executive function under stress mitigates the effects of recent life stress exposure on health in young adults

PubMed Central

Shields, Grant S.; Moons, Wesley G.; Slavich, George M.

2017-01-01

Executive function is a neuropsychological construct that enables controlled cognitive processing, which has been hypothesized to enhance individuals’ resilience to stress. However, little empirical work has directly examined how executive function under different conditions mitigates the negative effects of stress exposure on health. To address this issue, we recruited 110 healthy young adults and assessed their recent life stress exposure, executive function in either a stressful or non-stressful context, and current health complaints. Based on existing research, we hypothesized that individuals exhibiting better executive function following a laboratory-based stressor (but not a control task) would demonstrate weaker associations between recent stress exposure and health because they perceived recent life stressors as being less severe. Consistent with this hypothesis, better executive function during acute stress, but not in the absence of stress, was associated with an attenuated link between participants’ recent life stress exposure and their current health complaints. Moreover, this attenuating effect was mediated by lesser perceptions of stressor severity. Based on these data, we conclude that better executive function under stress is associated with fewer health complaints and that these effects may occur by reducing individuals’ perceptions of stressor severity. The data thus suggest the possibility of reducing stress-related health problems by enhancing executive function. PMID:28114849

Better executive function under stress mitigates the effects of recent life stress exposure on health in young adults.

PubMed

Shields, Grant S; Moons, Wesley G; Slavich, George M

2017-01-01

Executive function is a neuropsychological construct that enables controlled cognitive processing, which has been hypothesized to enhance individuals' resilience to stress. However, little empirical work has directly examined how executive function under different conditions mitigates the negative effects of stress exposure on health. To address this issue, we recruited 110 healthy young adults and assessed their recent life stress exposure, executive function in either a stressful or non-stressful context, and current health complaints. Based on existing research, we hypothesized that individuals exhibiting better executive function following a laboratory-based stressor (but not a control task) would demonstrate weaker associations between recent stress exposure and health because they perceived recent life stressors as being less severe. Consistent with this hypothesis, better executive function during acute stress, but not in the absence of stress, was associated with an attenuated link between participants' recent life stress exposure and their current health complaints. Moreover, this attenuating effect was mediated by lesser perceptions of stressor severity. Based on these data, we conclude that better executive function under stress is associated with fewer health complaints and that these effects may occur by reducing individuals' perceptions of stressor severity. The data thus suggest the possibility of reducing stress-related health problems by enhancing executive function.

The Stress Response and Adolescents' Adjustment: The Impact of Child Maltreatment

ERIC Educational Resources Information Center

Cook, Emily C.; Chaplin, Tara M.; Sinha, Rajita; Tebes, Jacob K.; Mayes, Linda C.

2012-01-01

Experience with and management of stress has implications for adolescents' behavioral and socioemotional development. This study examined the relationship between adolescents' physiological response to an acute laboratory stressor (i.e., Trier Social Stress Test; TSST) and anger regulation and interpersonal competence in a sample of 175 low-income…

Non-immediate reactions to beta-lactams: diagnostic value of skin testing and drug provocation test.

PubMed

Padial, A; Antunez, C; Blanca-Lopez, N; Fernandez, T D; Cornejo-Garcia, J A; Mayorga, C; Torres, M J; Blanca, M

2008-05-01

beta-Lactam (BL) antibiotics can induce non-immediate skin reactions, frequently manifested as exanthema or urticaria. The time between drug intake and the reaction appearance is generally 24-48 h. Because the mechanisms involved are not completely understood, diagnostic tests for these reactions have still to be fully validated. To evaluate the role of skin and drug provocation tests (DPTs) in the diagnosis of patients with non-immediate reactions to BL. We evaluated a group of 22 patients who developed maculopapular exanthema or urticarial exanthema after BL intake. Diagnosis was confirmed by DPT with BL. Intradermal/patch testing was performed with benzylpenicilloyl, minor determinant mixture, amoxicillin (AX), ampicillin (AMP) and the culprit drug in patients and in 22 negative controls. Immunohistochemical studies were done in the affected skin at the acute phase of the reaction and after a delayed positive skin test/DPT. IFN-gamma and IL-4 were quantified in peripheral mononuclear cells, obtained during the positive response to DPT and after resolution of the symptoms. From the total number of cases, 12 patients developed urticarial exanthema and 10 maculopapular exanthema after DPT. Only two of the 22 patients (9%) had a positive delayed intradermal skin test: one to AX/AMP and the other to cloxacillin. Biopsies showed a mononuclear CD4, CD8 infiltrate and activated and memory cells. The cytokine expression showed a Th1 pattern in patients, in contrast with the Th0 pattern in controls. In patients with non-immediate reactions to BLs (maculopapular exathema or urticarial exanthema), the sensitivity of skin testing is low and DPT may be required to establish the diagnosis. The reproducibility of the reactions and the cytokine pattern expressed during the acute episode support a T cell-induced non-immediate response.

Effects of natural enrichment materials on stress, memory and exploratory behavior in mice.

PubMed

Acklin, Casey J; Gault, Ruth A

2015-07-01

Environmental enrichment is an essential component of laboratory animal housing that allows animals to engage in natural behaviors in an otherwise artificial setting. Previous research by the authors suggested that, compared with synthetic enrichment materials, natural materials were associated with lower stress levels in mice. Here, the authors compare the effects of different enrichment materials on stress, memory and exploratory behavior in Swiss Webster mice. Mice that were provided with natural enrichment materials had lower stress levels, better memory and greater exploratory behavior than did mice provided with synthetic enrichment materials or with no enrichment materials. These findings suggest that provision of natural enrichment materials can improve well-being of laboratory mice.

Effect of Stress and Bupropion on Craving, Withdrawal Symptoms, and Mood in Smokers

PubMed Central

Drone, David; Thuras, Paul; Hatsukami, Dorothy K.; Brauer, Lisa; Adson, David E.; al’Absi, Mustafa

2011-01-01

Introduction: Studies suggest that in smokers attempting to quit smoking, the occurrence of stressful events is associated with smoking relapse. The purpose of this study was to determine the effect of bupropion (an agent known to increase smoking cessation rates) on the craving, withdrawal, and mood response to stressful tasks administered in a laboratory setting. Methods: Response to three tasks (a speech, math, and cold pressor task) was measured in 65 smokers during ad libitum smoking. Smokers were then randomized to either bupropion or placebo. Fourteen days after starting medication, 43 subjects (28 receiving bupropion and 15 receiving placebo) quit smoking and laboratory procedures were repeated on the third day of abstinence. Results: Prior to cessation, stressors presented in a laboratory setting increased craving, nicotine withdrawal symptoms, and subjective distress but decreased positive affect. Thirty minutes of relaxation after the stressors did not result in these measures returning to prestress levels. During the nicotine withdrawal period, stress-induced responses were generally smaller than during the precessation period. Bupropion (relative to placebo) reduced overall levels of craving and withdrawal symptoms but did not have significant effects on response to stress during the nicotine withdrawal period. Conclusions: This study demonstrates that stress results in sustained increases in craving and withdrawal symptoms and changes in mood symptoms and that bupropion affects overall levels of these symptoms. Further research is needed to determine if modifying response to stress is predictive of an effective treatment for facilitating smoking cessation. PMID:21378081

The Myth of Female Passivity: Thirty Years of Revelations about Female Aggression

ERIC Educational Resources Information Center

Richardson, Deborah South

2005-01-01

This article reviews an extensive program of research that has examined gender differences in aggressive behavior. Early research in the aggression laboratory that was designed to explain why females were nonaggressive actually revealed that females did respond to provocation and that they could not accurately be depicted as passive individuals.…

Colonoscopic allergen provocation test with rBet v 1 in patients with pollen-associated food allergy.

PubMed

Pickert, C N; Lorentz, A; Manns, M P; Bischoff, S C

2012-10-01

After consumption of fruits, nuts, and vegetables, several patients with pollen allergy experience gastrointestinal (GI) tract symptoms that are possibly caused by pollen-associated food allergy. The aim of this study was to evaluate the colonoscopic allergen provocation (COLAP) test using the recombinant birch pollen allergen Bet v 1 (rBet v 1) for in vivo diagnosis of pollen-associated food allergy manifesting in the GI tract. Thirty-four patients with a history of adverse reactions to food, GI tract symptoms, and birch pollen pollinosis and five healthy controls underwent COLAP test. Twenty minutes after endoscopic challenge of the cecal mucosa with rBet v 1, the mucosal wheal and flare reaction was registered semiquantitatively, and tissue biopsy specimens were examined for eosinophil mucosal activation. The mucosal reaction to rBet v 1 was correlated with the presence of pollinosis (P = 0.004), history of adverse reaction to Bet v 1-associated food allergens (P = 0.001), and tissue eosinophils' activation (P < 0.001). A wheal and flare reaction in the COLAP test was observed in 13 of 16 patients (81%) with a history of GI tract symptoms associated with the ingestion of Bet v 1-related foods and in four of 18 (22%) patients with a negative history (P < 0.001). The control group did not develop visible mucosal reactions to rBet v 1. Systemic anaphylactic reactions did not occur. The mucosal administration of rBet v 1 by COLAP test provides a new diagnostic tool that might support the diagnosis of Bet v 1-associated food allergy manifesting in the GI tract. © 2012 John Wiley & Sons A/S.

Chronic stress and brain plasticity: mechanisms underlying adaptive and maladaptive changes and implications for stress-related CNS disorders

PubMed Central

Radley, Jason; Morilak, David; Viau, Victor; Campeau, Serge

2015-01-01

Stress responses entail neuroendocrine, autonomic, and behavioral changes to promote effective coping with real or perceived threats to one’s safety. While these responses are critical for the survival of the individual, adverse effects of repeated exposure to stress are widely known to have deleterious effects on health. Thus, a considerable effort in the search for treatments to stress-related CNS disorders necessitates unraveling the brain mechanisms responsible for adaptation under acute conditions and their perturbations following chronic stress exposure. This paper is based upon a symposium from the 2014 International Behavioral Neuroscience Meeting, summarizing some recent advances in understanding the effects of stress on adaptive and maladaptive responses subserved by limbic forebrain networks. An important theme highlighted in this review is that the same networks mediating neuroendocrine, autonomic, and behavioral processes during adaptive coping also comprise targets of the effects of repeated stress exposure in the development of maladaptive states. Where possible, reference is made to the similarity of neurobiological substrates and effects observed following repeated exposure to stress in laboratory animals and the clinical features of stress-related disorders in humans. PMID:26116544

The role of chronic psychosocial stress in explaining racial differences in stress reactivity and pain sensitivity

PubMed Central

Gordon, Jennifer L.; Johnson, Jacqueline; Nau, Samantha; Mechlin, Beth; Girdler, Susan S.

2016-01-01

Objective To examine the role of psychosocial factors in mediating the relationship between African American (AA) race and both increased pain sensitivity and blunted stress reactivity. Methods Participants included 133 AA and non-Hispanic White (nHW) individuals (mean (SD) age = 37 (9)) matched for age, sex and socioeconomic status. Participants underwent mental stress testing (Trier Social Stress Test) while cardiovascular, hemodynamic, and neuroendocrine reactivity were measured. Participants completed questionnaires assessing potential sources of psychosocial stress and were tested for pain responses to cold pain and the temporal summation of heat pulses. Mediation analyses were used to determine the extent to which exposure to psychosocial stress accounted for the observed racial differences in stress reactivity and pain. Results Chronic stress exposure and reactivity to mental stress was largely similar among AAs and nHWs; however, AAs exhibited heightened pain to both cold (p = .012) and heat (p = .004). Racial differences in the relationship between stress reactivity and pain were also observed: while greater stress reactivity was associated with decreased pain among nHWs, reactivity was either unrelated to or even positively associated with pain among AAs (e.g. r = −.21 among nHWs and r = .41 among AAs for stroke volume reactivity and cold pressor intensity). Adjusting for minor racial differences in chronic psychosocial stress did not change these findings. Conclusion Accounting for psychosocial factors eliminated racial differences in stress reactivity but not racial differences in sensitivity to experimental pain tasks. Increased exposure to chronic stress may not explain AAs’ increased pain sensitivity in laboratory settings. PMID:27669431

The Role of Chronic Psychosocial Stress in Explaining Racial Differences in Stress Reactivity and Pain Sensitivity.

PubMed

Gordon, Jennifer L; Johnson, Jacqueline; Nau, Samantha; Mechlin, Beth; Girdler, Susan S

To examine the role of psychosocial factors in mediating the relationship between African American (AA) race and both increased pain sensitivity and blunted stress reactivity. Participants included 133 AA and non-Hispanic white (nHW) individuals (mean [SD] age, 37 [9]) matched for age, sex, and socioeconomic status. Participants underwent mental stress testing (Trier Social Stress Test) while cardiovascular, hemodynamic, and neuroendocrine reactivity were measured. Participants completed questionnaires assessing potential sources of psychosocial stress and were tested for pain responses to cold pain and the temporal summation of heat pulses. Mediation analyses were used to determine the extent to which exposure to psychosocial stress accounted for the observed racial differences in stress reactivity and pain. Chronic stress exposure and reactivity to mental stress was largely similar among AAs and nHWs; however, AAs exhibited heightened pain to both cold (p = .012) and heat (p = .004). Racial differences in the relationship between stress reactivity and pain were also observed: while greater stress reactivity was associated with decreased pain among nHWs, reactivity was either unrelated to or even positively associated with pain among AAs (e.g., r = -.21 among nHWs and r = .41 among AAs for stroke volume reactivity and cold pressor intensity). Adjusting for minor racial differences in chronic psychosocial stress did not change these findings. Accounting for psychosocial factors eliminated racial differences in stress reactivity but not racial differences in sensitivity to experimental pain tasks. Increased exposure to chronic stress may not explain AAs' increased pain sensitivity in laboratory settings.

Physiological stress in air traffic controllers : a review.

DOT National Transportation Integrated Search

1982-08-01

Ten years of research on physiological stress in air traffic control specialists (ATCS's) is reviewed. Data were derived from 20 tasks involving the experimental variables of workload, shift-rotation patterns, and automation. : Laboratories at the Ci...

The role of multiple negative social relationships in inflammatory cytokine responses to a laboratory stressor

PubMed Central

Song, Sunmi; Graham-Engeland, Jennifer E.; Corwin, Elizabeth J.; Ceballos, Rachel M.; Taylor, Shelley E.; Seeman, Teresa

2015-01-01

The present study examined the unique impact of perceived negativity in multiple social relationships on endocrine and inflammatory responses to a laboratory stressor. Via hierarchical cluster analysis, those who reported negative social exchanges across relationships with a romantic partner, family, and their closest friend had higher mean IL-6 across time and a greater increase in TNF-α from 15 min to 75 min post stress. Those who reported negative social exchanges across relationships with roommates, family, and their closest friend showed greater IL-6 responses to stress. Differences in mean IL-6 were accounted for by either depressed mood or hostility, whereas differences in the cytokine stress responses remained significant after controlling for those factors. Overall, this research provides preliminary evidence to suggest that having multiple negative relationships may exacerbate acute inflammatory responses to a laboratory stressor independent of hostility and depressed mood. PMID:26056615

The role of multiple negative social relationships in inflammatory cytokine responses to a laboratory stressor.

PubMed

Song, Sunmi; Graham-Engeland, Jennifer E; Corwin, Elizabeth J; Ceballos, Rachel M; Taylor, Shelley E; Seeman, Teresa; Klein, Laura Cousino

2015-01-01

The present study examined the unique impact of perceived negativity in multiple social relationships on endocrine and inflammatory responses to a laboratory stressor. Via hierarchical cluster analysis, those who reported negative social exchanges across relationships with a romantic partner, family, and their closest friend had higher mean IL-6 across time and a greater increase in TNF-α from 15 min to 75 min post stress. Those who reported negative social exchanges across relationships with roommates, family, and their closest friend showed greater IL-6 responses to stress. Differences in mean IL-6 were accounted for by either depressed mood or hostility, whereas differences in the cytokine stress responses remained significant after controlling for those factors. Overall, this research provides preliminary evidence to suggest that having multiple negative relationships may exacerbate acute inflammatory responses to a laboratory stressor independent of hostility and depressed mood.

Negative cognitive style and cortisol recovery accentuate the relationship between life stress and depressive symptoms.

PubMed

Quinn, Meghan E; Grant, Kathryn E; Adam, Emma K

2018-03-01

When exposed to stressful life events, a significant number of adolescents will experience depressive symptoms. One model of depression suggests that individuals with a negative cognitive style are most vulnerable to depression following life stress. Alternatively, altered activation of the hypothalamic-pituitary-adrenal axis may explain vulnerability to depression following life stress. Each of these models plausibly explains the emergence of depressive symptoms during adolescence and have been investigated largely independently. The current study recruited a sample of urban adolescents (N = 179) to evaluate whether cortisol response to a laboratory stress induction and negative cognitive style are related and whether they independently interact with exposure to stressful life events to predict symptoms of depression. Negative cognitive style was not associated with cortisol response to the laboratory stressor. Rather, negative cognitive style and cortisol recovery independently interacted with stressful life events to predict current symptoms of depression. Results support a heterogeneous etiology of depression.

A TRANSLATIONAL INVESTIGATION TARGETING STRESS-REACTIVITY AND PRE-FRONTAL COGNITIVE CONTROL WITH GUANFACINE FOR SMOKING CESSATION

PubMed Central

McKee, Sherry A.; Potenza, Marc N.; Kober, Hedy; Sofuoglu, Mehmet; Arnsten, Amy F. T.; Picciotto, Marina R.; Weinberger, Andrea H.; Ashare, Rebecca; Sinha, Rajita

2015-01-01

Stress and pre-frontal cognitive dysfunction have key roles in driving smoking, however, there are no therapeutics for smoking cessation which attenuate the effects of stress on smoking and enhance cognition. Central noradrenergic pathways are involved in stress-induced reinstatement to nicotine and in the prefrontal executive control of adaptive behaviors. We used a novel translational approach employing a validated laboratory analogue of stress-precipitated smoking, fMRI, and a proof-of-concept treatment period to evaluate whether the noradrenergic α2a agonist, guanfacine (3mg/day) versus placebo (0mg/day) reduced stress-precipitated smoking in the laboratory, altered cortico-striatal activation during the Stroop cognitive-control task, and reduced smoking following a quit attempt. In nicotine-deprived smokers (n=33), stress versus a neutral condition significantly decreased the latency to smoke, and increased tobacco craving, ad-libitum smoking, and systolic blood pressure in placebo-treated subjects, and these effects were absent or reduced in guanfacine-treated subjects. Following stress, placebo-treated subjects demonstrated decreased cortisol levels whereas guanfacine-treated subjects demonstrated increased levels. Guanfacine, compared to placebo, altered prefrontal activity during a cognitive control task, and reduced cigarette use but did not increase complete abstinence during treatment. These preliminary laboratory, neuroimaging and clinical outcome data were consistent and complementary and support further development of guanfacine for smoking cessation. PMID:25516371

Capacitive Sensing for Non-Invasive Breathing and Heart Monitoring in Non-Restrained, Non-Sedated Laboratory Mice.

PubMed

González-Sánchez, Carlos; Fraile, Juan-Carlos; Pérez-Turiel, Javier; Damm, Ellen; Schneider, Jochen G; Zimmermann, Heiko; Schmitt, Daniel; Ihmig, Frank R

2016-07-07

Animal testing plays a vital role in biomedical research. Stress reduction is important for improving research results and increasing the welfare and the quality of life of laboratory animals. To estimate stress we believe it is of great importance to develop non-invasive techniques for monitoring physiological signals during the transport of laboratory animals, thereby allowing the gathering of information on the transport conditions, and, eventually, the improvement of these conditions. Here, we study the suitability of commercially available electric potential integrated circuit (EPIC) sensors, using both contact and contactless techniques, for monitoring the heart rate and breathing rate of non-restrained, non-sedated laboratory mice. The design has been tested under different scenarios with the aim of checking the plausibility of performing contactless capture of mouse heart activity (ideally with an electrocardiogram). First experimental results are shown.

Wakata wearing Penguin-3 Antigravity Pressure/Stress Suit

NASA Image and Video Library

2014-01-25

ISS038-E-035473 (24 Jan. 2014) --- Japan Aerospace Exploration Agency astronaut Koichi Wakata, Expedition 38 flight engineer, is pictured wearing the Penguin-3 antigravity pressure/stress suit in the Kibo laboratory of the International Space Station.

Wakata wearing Penguin-3 Antigravity Pressure/Stress Suit

NASA Image and Video Library

2014-01-25

ISS038-E-035476 (24 Jan. 2014) --- Japan Aerospace Exploration Agency astronaut Koichi Wakata, Expedition 38 flight engineer, is pictured wearing the Penguin-3 antigravity pressure/stress suit in the Kibo laboratory of the International Space Station.

Wakata wearing Penguin-3 Antigravity Pressure/Stress Suit

NASA Image and Video Library

2014-01-24

ISS038-E-035470 (24 Jan. 2014) --- Japan Aerospace Exploration Agency astronaut Koichi Wakata, Expedition 38 flight engineer, is pictured wearing the Penguin-3 antigravity pressure/stress suit in the Kibo laboratory of the International Space Station.

Stress-Induced Reinstatement of Drug Seeking: 20 Years of Progress

PubMed Central

Mantsch, John R; Baker, David A; Funk, Douglas; Lê, Anh D; Shaham, Yavin

2016-01-01

In human addicts, drug relapse and craving are often provoked by stress. Since 1995, this clinical scenario has been studied using a rat model of stress-induced reinstatement of drug seeking. Here, we first discuss the generality of stress-induced reinstatement to different drugs of abuse, different stressors, and different behavioral procedures. We also discuss neuropharmacological mechanisms, and brain areas and circuits controlling stress-induced reinstatement of drug seeking. We conclude by discussing results from translational human laboratory studies and clinical trials that were inspired by results from rat studies on stress-induced reinstatement. Our main conclusions are (1) The phenomenon of stress-induced reinstatement, first shown with an intermittent footshock stressor in rats trained to self-administer heroin, generalizes to other abused drugs, including cocaine, methamphetamine, nicotine, and alcohol, and is also observed in the conditioned place preference model in rats and mice. This phenomenon, however, is stressor specific and not all stressors induce reinstatement of drug seeking. (2) Neuropharmacological studies indicate the involvement of corticotropin-releasing factor (CRF), noradrenaline, dopamine, glutamate, kappa/dynorphin, and several other peptide and neurotransmitter systems in stress-induced reinstatement. Neuropharmacology and circuitry studies indicate the involvement of CRF and noradrenaline transmission in bed nucleus of stria terminalis and central amygdala, and dopamine, CRF, kappa/dynorphin, and glutamate transmission in other components of the mesocorticolimbic dopamine system (ventral tegmental area, medial prefrontal cortex, orbitofrontal cortex, and nucleus accumbens). (3) Translational human laboratory studies and a recent clinical trial study show the efficacy of alpha-2 adrenoceptor agonists in decreasing stress-induced drug craving and stress-induced initial heroin lapse. PMID:25976297

Geophysical Properties of Hard Rock for Investigation of Stress Fields in Deep Mines

NASA Astrophysics Data System (ADS)

Tibbo, M.; Young, R. P.; Schmitt, D. R.; Milkereit, B.

2014-12-01

A complication in geophysical monitoring of deep mines is the high-stress dependency of the physical properties of hard rocks. In-mine observations show anisotropic variability of the in situ P- and S-wave velocities and resistivity of the hard rocks that are likely related to stress field changes. As part of a comprehensive study in a deep, highly stressed mine located in Sudbury, Ontario, Canada, data from in situ monitoring of the seismicity, conductivity, stress, and stress dependent physical properties has been obtain. In-laboratory experiments are also being performed on borehole cores from the Sudbury mines. These experiments will measure the Norite borehole core's properties including elastic modulus, bulk modulus, P- and S-wave velocities, and density. Hydraulic fracturing has been successfully implemented in industries such as oil and gas and enhanced geothermal systems, and is currently being investigated as a potential method for preconditioning in mining. However, further research is required to quantify how hydraulic fractures propagate through hard, unfractured rock as well as naturally fractured rock typically found in mines. These in laboratory experiments will contribute to a hydraulic fracturing project evaluating the feasibility and effectiveness of hydraulic fracturing as a method of de-stressing hard rock mines. A tri-axial deformation cell equipped with 18 Acoustic Emission (AE) sensors will be used to bring the borehole cores to a tri-axial state of stress. The cores will then be injected with fluid until the the hydraulic fracture has propagated to the edge of the core, while AE waveforms will be digitized continuously at 10 MHz and 12-bit resolution for the duration of each experiment. These laboratory hydraulic fracture experiments will contribute to understanding how parameters including stress ratio, fluid injection rate, and viscosity, affect the fracturing process.

Neuroscience of opiates for addiction medicine: From stress-responsive systems to behavior.

PubMed

Zhou, Yan; Leri, Francesco

2016-01-01

Opiate addiction, similarly to addiction to other psychoactive drugs, is chronic relapsing brain disease caused by drug-induced short-term and long-term neuroadaptations at the molecular, cellular, and behavioral levels. Preclinical research in laboratory animals has found important interactions between opiate exposure and stress-responsive systems. In this review, we will discuss the dysregulation of several stress-responsive systems in opiate addiction: vasopressin and its receptor system, endogenous opioid systems (including proopiomelanocortin/mu opioid receptor and dynorphin/kappa opioid receptor), orexin and its receptor system, and the hypothalamic-pituitary-adrenal axis. A more complete understanding of how opiates alter these stress systems, through further laboratory-based studies, is required to identify novel and effective pharmacological targets for the long-term treatment of heroin addiction. © 2016 Elsevier B.V. All rights reserved.

Measuring State-Specific Rumination: Development of the Rumination about an Interpersonal Offense Scale

ERIC Educational Resources Information Center

Wade, Nathaniel G.; Vogel, David L.; Liao, Kelly Yu-Hsin; Goldman, Daniel B.

2008-01-01

The tendency to ruminate has been consistently linked to psychological disturbances, such as increased stress, anger, and fear in response to provocations. However, existing measures of rumination focus on the disposition to ruminate rather than on rumination about a specific situation. This limits the ability to explore rumination about a…

Outreach Plans for Storm Peak Laboratory

NASA Astrophysics Data System (ADS)

Hallar, A. G.; McCubbin, I. B.

2006-12-01

The Desert Research Institute (DRI) operates a high elevation facility, Storm Peak Laboratory (SPL), located on the west summit of Mt. Werner in the Park Range near Steamboat Springs, Colorado at an elevation 10,500 ft. SPL provides an ideal location for long-term research on the interactions of atmospheric aerosol and gas- phase chemistry with cloud and natural radiation environments. SPL includes an office-type laboratory room for computer and instrumentation setup with outside air ports and cable access to the roof deck, a full kitchen and two bunk rooms with sleeping space for nine persons. We plan to create a unique summer undergraduate education experiences for students of diversity at Storm Peak Laboratory. As stressed by the College Pathways to Science Education Standards [Siebert and McIntosh, 2001], to support changes in K-12 science education transformations must first be made at the college level, including inquiry-oriented opportunities to engage in meaningful research. These workshops will be designed to allow students to experience the excitement of science, increasing their likelihood of pursing careers within the fields of scientific education or research.

Intrinsic rotation from a residual stress at the boundary of a cylindrical laboratory plasma.

PubMed

Yan, Z; Xu, M; Diamond, P H; Holland, C; Müller, S H; Tynan, G R; Yu, J H

2010-02-12

An azimuthally symmetric radially sheared azimuthal flow is driven by a nondiffusive, or residual, turbulent stress localized to a narrow annular region at the boundary of a cylindrical magnetized helicon plasma device. A no-slip condition, imposed by ion-neutral flow damping outside the annular region, combined with a diffusive stress arising from turbulent and collisional viscous damping in the central plasma region, leads to net plasma rotation in the absence of momentum input.

Moderate psychosocial stress appears not to impair recall of words learned 4 weeks prior to stress exposure.

PubMed

Wolf, Oliver T; Schommer, Nicole C; Hellhammer, Dirk H; Reischies, Friedel M; Kirschbaum, Clemens

2002-02-01

Recent studies in humans have reported that recall of previously learned material is especially sensitive to the disruptive effects of pharmacologically induced cortisol elevations. Whether similar effects occur after exposure to psychosocial stress remains to be shown. Moreover it is unknown whether stress before or after the initial learning interacts with the later effects of repeated stress on delayed recall (e.g. state-dependent learning). Forty subjects participated in the present experiment. They learned a word list either one hour before or 10 min after exposure to a psychosocial laboratory stressor. Delayed recall was tested 4 weeks later, again either before or after stress. Salivary cortisol levels increased significantly in response to both stress exposures. Stress had no effects on the initial learning and also did not impair delayed recall. Moreover there was no evidence for state-dependent learning. The current data seem to be in conflict with previous studies demonstrating that delayed recall is especially sensitive to elevated cortisol levels. Several reasons for these discrepancies are discussed. Among them is the small sample size, the moderate cortisol increase in response to the second stress exposure but also the long recall delay, which might lead to memory traces less susceptible to stress.

Influence of precracked specimen configuration and starting stress intensity on the stress corrosion cracking of 4340 steel

NASA Technical Reports Server (NTRS)

Lisagor, W. B.

1984-01-01

Since the pioneer work of Brown (1966), precracked specimens and related fracture mechanics analyses have been extensively used to study stress corrosion cracking. Certain questions arose in connection with initial attempts to prepare standardized recommended practices by ASTM Committee G-1 on Corrosion of Metals. These questions were related to adequacy of test control as it pertains to acceptable limits of variability, and to validity of expressions for stress intensity and crack-surface displacements for both specimen configurations. An interlaboratory test program, was, therefore, planned with the objective to examine the validity of KIscc testing for selected specimen configurations, materials,and environmental systems. The results reported in the present paper include details of a single laboratory test program. The program was conducted to determine if the threshold value of stress intensity for onset and arrest of stress corrosion cracking was independent for the two specimen configurations examined.

Stress Related Overeating Among College Students: Development of a Mood Eating Scale.

ERIC Educational Resources Information Center

Jackson, Linda J.; Hawkins, Raymond C.

The hypothesis that negative emotional life states accompanying life stresses are associated with overeating and weight gain cannot be adequately tested solely by laboratory analogue studies. Naturalistic, short-term longitudinal designs are needed in which individuals susceptible to mood eating can be identified prior to a stressful event and…

A Randomized Dose-Ranging Study of Neuropeptide Y in Patients with Posttraumatic Stress Disorder.

PubMed

Sayed, Sehrish; Van Dam, Nicholas T; Horn, Sarah R; Kautz, Marin M; Parides, Michael; Costi, Sara; Collins, Katherine A; Iacoviello, Brian; Iosifescu, Dan V; Mathé, Aleksander A; Southwick, Steven M; Feder, Adriana; Charney, Dennis S; Murrough, James W

2018-01-01

Anxiety and trauma-related disorders are among the most prevalent and disabling medical conditions in the United States, and posttraumatic stress disorder in particular exacts a tremendous public health toll. We examined the tolerability and anxiolytic efficacy of neuropeptide Y administered via an intranasal route in patients with posttraumatic stress disorder. Twenty-six individuals were randomized in a cross-over, single ascending dose study into 1 of 5 cohorts: 1.4 mg (n=3), 2.8 mg (n=6), 4.6 mg (n=5), 6.8 mg (n=6), and 9.6 mg (n=6). Each individual was dosed with neuropeptide Y or placebo on separate treatment days 1 week apart in random order under double-blind conditions. Assessments were conducted at baseline and following a trauma script symptom provocation procedure subsequent to dosing. Occurrence of adverse events represented the primary tolerability outcome. The difference between treatment conditions on anxiety as measured by the Beck Anxiety Inventory and the State-Trait Anxiety Inventory immediately following the trauma script represented efficacy outcomes. Twenty-four individuals completed both treatment days. Neuropeptide Y was well tolerated up to and including the highest dose. There was a significant interaction between treatment and dose; higher doses of neuropeptide Y were associated with a greater treatment effect, favoring neuropeptide Y over placebo on Beck Anxiety Inventory score (F1,20=4.95, P=.038). There was no significant interaction for State-Trait Anxiety Inventory score. Our study suggests that a single dose of neuropeptide Y is well tolerated up to 9.6 mg and may be associated with anxiolytic effects. Future studies exploring the safety and efficacy of neuropeptide Y in stress-related disorders are warranted. The reported study is registered at: http://clinicaltrials.gov (ID: NCT01533519). © The Author(s) 2017. Published by Oxford University Press on behalf of CINP.

Evaluation of bed load transport subject to high shear stress fluctuations

NASA Astrophysics Data System (ADS)

Cheng, Nian-Sheng; Tang, Hongwu; Zhu, Lijun

2004-05-01

Many formulas available in the literature for computing sediment transport rates are often expressed in terms of time mean variables such as time mean bed shear stress or flow velocity, while effects of turbulence intensity, e.g., bed shear stress fluctuation, on sediment transport were seldom considered. This may be due to the fact that turbulence fluctuation is relatively limited in laboratory open-channel flows, which are often used for conducting sediment transport experiments. However, turbulence intensity could be markedly enhanced in practice. This note presents an analytical method to compute bed load transport by including effects of fluctuations in the bed shear stress. The analytical results obtained show that the transport rate enhanced by turbulence can be expressed as a simple function of the relative fluctuation of the bed shear stress. The results are also verified using data that were collected recently from specifically designed laboratory experiments. The present analysis is applicable largely for the condition of a flat bed that is comprised of uniform sand particles subject to unidirectional flows.

Approaches to detection of geochemical stress in vegetation

NASA Astrophysics Data System (ADS)

Horler, D. N. H.; Barber, J.; Darch, J. P.; Ferns, D. C.; Barringer, A. R.

Work has been carried out to elucidate fundamental relationships between spectral properties of plants and geochemical stress, and a programme of field and laboratory work is in progress. The most significant results and conclusions at this stage are described and attention is focused on the new concepts for stress detection which have been generated. The applications of the research are relevant to the understanding of current remotely sensed data as well as relating to ideas for new instrumentation.

Approaches to detection of geochemical stress in vegetation

NASA Technical Reports Server (NTRS)

Horler, D. N. H.; Barber, J.; Darch, J. P.; Ferns, D. C.; Barringer, A. R.

1983-01-01

Work has been carried out to elucidate fundamental relationships between spectral properties of plants and geochemical stress, and a programme of field and laboratory work is in progress. The most significant results and conclusions at this stage are described and attention is focused on the new concepts for stress detection which have been generated. The applications of the research are relevant to the understanding of current remotely sensed data as well as relating to ideas for new instrumentation.

Association of Constitutive Hyperphosphorylation of Hsf1p with a Defective Ethanol Stress Response in Saccharomyces cerevisiae Sake Yeast Strains

PubMed Central

Noguchi, Chiemi; Watanabe, Daisuke; Zhou, Yan; Akao, Takeshi

2012-01-01

Modern sake yeast strains, which produce high concentrations of ethanol, are unexpectedly sensitive to environmental stress during sake brewing. To reveal the underlying mechanism, we investigated a well-characterized yeast stress response mediated by a heat shock element (HSE) and heat shock transcription factor Hsf1p in Saccharomyces cerevisiae sake yeast. The HSE-lacZ activity of sake yeast during sake fermentation and under acute ethanol stress was severely impaired compared to that of laboratory yeast. Moreover, the Hsf1p of modern sake yeast was highly and constitutively hyperphosphorylated, irrespective of the extracellular stress. Since HSF1 allele replacement did not significantly affect the HSE-mediated ethanol stress response or Hsf1p phosphorylation patterns in either sake or laboratory yeast, the regulatory machinery of Hsf1p is presumed to function differently between these types of yeast. To identify phosphatases whose loss affected the control of Hsf1p, we screened a series of phosphatase gene deletion mutants in a laboratory strain background. Among the 29 mutants, a Δppt1 mutant exhibited constitutive hyperphosphorylation of Hsf1p, similarly to the modern sake yeast strains, which lack the entire PPT1 gene locus. We confirmed that the expression of laboratory yeast-derived functional PPT1 recovered the HSE-mediated stress response of sake yeast. In addition, deletion of PPT1 in laboratory yeast resulted in enhanced fermentation ability. Taken together, these data demonstrate that hyperphosphorylation of Hsf1p caused by loss of the PPT1 gene at least partly accounts for the defective stress response and high ethanol productivity of modern sake yeast strains. PMID:22057870

Association of constitutive hyperphosphorylation of Hsf1p with a defective ethanol stress response in Saccharomyces cerevisiae sake yeast strains.

PubMed

Noguchi, Chiemi; Watanabe, Daisuke; Zhou, Yan; Akao, Takeshi; Shimoi, Hitoshi

2012-01-01

Modern sake yeast strains, which produce high concentrations of ethanol, are unexpectedly sensitive to environmental stress during sake brewing. To reveal the underlying mechanism, we investigated a well-characterized yeast stress response mediated by a heat shock element (HSE) and heat shock transcription factor Hsf1p in Saccharomyces cerevisiae sake yeast. The HSE-lacZ activity of sake yeast during sake fermentation and under acute ethanol stress was severely impaired compared to that of laboratory yeast. Moreover, the Hsf1p of modern sake yeast was highly and constitutively hyperphosphorylated, irrespective of the extracellular stress. Since HSF1 allele replacement did not significantly affect the HSE-mediated ethanol stress response or Hsf1p phosphorylation patterns in either sake or laboratory yeast, the regulatory machinery of Hsf1p is presumed to function differently between these types of yeast. To identify phosphatases whose loss affected the control of Hsf1p, we screened a series of phosphatase gene deletion mutants in a laboratory strain background. Among the 29 mutants, a Δppt1 mutant exhibited constitutive hyperphosphorylation of Hsf1p, similarly to the modern sake yeast strains, which lack the entire PPT1 gene locus. We confirmed that the expression of laboratory yeast-derived functional PPT1 recovered the HSE-mediated stress response of sake yeast. In addition, deletion of PPT1 in laboratory yeast resulted in enhanced fermentation ability. Taken together, these data demonstrate that hyperphosphorylation of Hsf1p caused by loss of the PPT1 gene at least partly accounts for the defective stress response and high ethanol productivity of modern sake yeast strains.

Aerothermodynamic Design of the Mars Science Laboratory Heatshield

NASA Technical Reports Server (NTRS)

Edquist, Karl T.; Dyakonov, Artem A.; Wright, Michael J.; Tang, Chun Y.

2009-01-01

Aerothermodynamic design environments are presented for the Mars Science Laboratory entry capsule heatshield. The design conditions are based on Navier-Stokes flowfield simulations on shallow (maximum total heat load) and steep (maximum heat flux, shear stress, and pressure) entry trajectories from a 2009 launch. Boundary layer transition is expected prior to peak heat flux, a first for Mars entry, and the heatshield environments were defined for a fully-turbulent heat pulse. The effects of distributed surface roughness on turbulent heat flux and shear stress peaks are included using empirical correlations. Additional biases and uncertainties are based on computational model comparisons with experimental data and sensitivity studies. The peak design conditions are 197 W/sq cm for heat flux, 471 Pa for shear stress, 0.371 Earth atm for pressure, and 5477 J/sq cm for total heat load. Time-varying conditions at fixed heatshield locations were generated for thermal protection system analysis and flight instrumentation development. Finally, the aerothermodynamic effects of delaying launch until 2011 are previewed.

Simultaneous Changes in Sleep, qEEG, Physiology, Behaviour and Neurochemistry in Rats Exposed to Repeated Social Defeat Stress.

PubMed

Ahnaou, A; Drinkenburg, W H I M

2016-01-01

Depression is a heterogeneous disorder characterized by alterations at psychological, behavioural, physiological, neurophysiological, and neurochemical levels. Social stress is a prevalent stress in man, and the repeated social defeat stress model in rats has been proposed as being the rodent equivalent to loss of control, which in subordinate animals produces alterations that resemble several of the cardinal symptoms found in depressed patients. Here, rats followed a resident-intruder protocol for 4 consecutive days during which behavioural, physiological, and electroencephalographic (EEG) parameters were simultaneously monitored in subordinate rats. On day 5, prefrontal dopamine (DA) and hippocampal serotonin (5-HT) as well as corticosterone were measured in submissive rats that had visual, acoustic, and olfactory (but no physical) contact with a dominant, resident conspecific rat. Socially defeated rats demonstrated increases in ultrasonic vocalizations (20-25 KHz), freezing, submissive defensive behaviour, inactivity, and haemodynamic response, while decreases were found in repetitive grooming behaviour and body weight. Additionally, alterations in the sleep-wake architecture were associated with reduced active waking, enhanced light sleep, and increased frequency of transitions from light sleep to quiet wakefulness, indicating sleep instability. Moreover, the attenuation of EEG power over the frequency range of 4.2-30 Hz, associated with a sharp transient increase in delta oscillations, appeared to reflect increased brain activity and metabolism in subordinate animals. These EEG changes were synchronous with a marked increase in body temperature and a decrease in locomotor activity. Furthermore, psychosocial stress consistently increased 5-HT, DA, and corticosterone levels. The increased levels of cortical DA and hippocampal 5-HT during social threat may reflect a coping mechanism to promote alertness and psychological adaptation to provocative and threatening

Adaptive laboratory evolution – principles and applications for biotechnology

PubMed Central

2013-01-01

Adaptive laboratory evolution is a frequent method in biological studies to gain insights into the basic mechanisms of molecular evolution and adaptive changes that accumulate in microbial populations during long term selection under specified growth conditions. Although regularly performed for more than 25 years, the advent of transcript and cheap next-generation sequencing technologies has resulted in many recent studies, which successfully applied this technique in order to engineer microbial cells for biotechnological applications. Adaptive laboratory evolution has some major benefits as compared with classical genetic engineering but also some inherent limitations. However, recent studies show how some of the limitations may be overcome in order to successfully incorporate adaptive laboratory evolution in microbial cell factory design. Over the last two decades important insights into nutrient and stress metabolism of relevant model species were acquired, whereas some other aspects such as niche-specific differences of non-conventional cell factories are not completely understood. Altogether the current status and its future perspectives highlight the importance and potential of adaptive laboratory evolution as approach in biotechnological engineering. PMID:23815749

4-Phenylbutyrate Benefits Traumatic Hemorrhagic Shock in Rats by Attenuating Oxidative Stress, Not by Attenuating Endoplasmic Reticulum Stress.

PubMed

Yang, Guangming; Peng, Xiaoyong; Hu, Yi; Lan, Dan; Wu, Yue; Li, Tao; Liu, Liangming

2016-07-01

Vascular dysfunction such as vascular hyporeactivity following severe trauma and shock is a major cause of death in injured patients. Oxidative stress and endoplasmic reticulum stress play an important role in vascular dysfunction. The objective of the present study was to determine whether or not 4-phenylbutyrate can improve vascular dysfunction and elicit antishock effects by inhibiting oxidative and endoplasmic reticulum stress. Prospective, randomized, controlled laboratory experiment. State key laboratory of trauma, burns, and combined injury. Five hundred and fifty-two Sprague-Dawley rats. Rats were anesthetized, and a model of traumatic hemorrhagic shock was established by left femur fracture and hemorrhage. The effects of 4-phenylbutyrate (5, 20, 50, 100, 200, and 300 mg/kg) on vascular reactivity, animal survival, hemodynamics, and vital organ function in traumatic hemorrhagic shock rats and cultured vascular smooth muscle cells, and the relationship to oxidative stress and endoplasmic reticulum stress was observed. Lower doses of 4-phenylbutyrate significantly improved the vascular function, stabilized the hemodynamics, and increased the tissue blood flow and vital organ function in traumatic hemorrhagic shock rats, and markedly improved the survival outcomes. Among all dosages observed in the present study, 20 mg/kg of 4-phenylbutyrate had the best effect. Further results indicated that 4-phenylbutyrate significantly inhibited the oxidative stress, decreased shock-induced oxidative stress index such as the production of reactive oxygen species, increased the antioxidant enzyme levels such as superoxide dismutase, catalase, and glutathione, and improved the mitochondrial function by inhibiting the opening of the mitochondrial permeability transition pore in rat artery and vascular smooth muscle cells. In contrast, 4-phenylbutyrate did not affect the changes of endoplasmic reticulum stress markers following traumatic hemorrhagic shock. Furthermore, 4

Geomechanical Behaviors of Laboratory-Formed Non-Cementing Hydrate-Bearing Sediments

NASA Astrophysics Data System (ADS)

Seol, Y.

2015-12-01

Natural hydrate-bearing sediments (HBS) have been known to exist with non-cementing pore habits, i.e., pore-filling, load-bearing, or patchy type. However, few laboratory studies have been conducted to characterize geomechanical behaviors of non-cementing CH4-HBS, which are of great importance in engineering the process of drilling and gas production in natural hydrate reservoir. In this study, we conducted multi-stage drained triaxial tests on laboratory synthesized CH4-HBS samples, which were formed in sand-clay mixtures (5%wt kaolinite) to have non-cementing habits. Three different effective confining stresses, σ3' = 0.69, 1.38, and 2.76 MPa, were applied on the HBS with the hydrate saturation, Sh, in the range of 0 to ~ 40%. The result confirms that the strength and stiffness of HBS increases with effective confining stress and hydrate saturation. It is also demonstrated that when compared to the cementing HBS, the non-cementing HBS has lower strength and cohesion, owing to less inter-particle adhesion effects from non-cementing hydrate.

Experiments on stress dependent borehole acoustic waves.

PubMed

Hsu, Chaur-Jian; Kane, Michael R; Winkler, Kenneth; Wang, Canyun; Johnson, David Linton

2011-10-01

In the laboratory setup, a borehole traverses a dry sandstone formation, which is subjected to a controlled uniaxial stress in the direction perpendicular to the borehole axis. Measurements are made in a single loading-unloading stress cycle from zero to 10 MPa and then back down to zero stress. The applied stress and the presence of the borehole induce anisotropy in the bulk of the material and stress concentration around the borehole, both azimuthally and radially. Acoustic waves are generated and detected in the water-filled borehole, including compressional and shear headwaves, as well as modes of monopole, dipole, quadrupole, and higher order azimuthal symmetries. The linear and non-linear elastic parameters of the formation material are independently quantified, and utilized in conjunction with elastic theories to predict the characteristics of various borehole waves at zero and finite stress conditions. For example, an analytic theory is developed which is successfully used to estimate the changes of monopole tube mode at low frequency resulted from uniaxial stress, utilizing the measured material third order elasticity parameters. Comparisons between various measurements as well as that between experiments and theories are also presented. © 2011 Acoustical Society of America

Dental Laboratory Career Ladder (AFSC 4Y1X1)

DTIC Science & Technology

1994-08-01

analysis identified one job cluster and seven jobs: Base Dental Lab cluster, Orthodontic Appliance Fabricator job, Fixed Restoration Fabricator job, Crown...reline and repair, removable partial denture construction, crown and fixed partial denture construction, fabrication of orthodontic appliances, and...specialized prostheses. Preventive maintenance and safety precautions for dental laboratory equipment are also stressed . Entry into the career ladder

Effects of trauma-related audiovisual stimulation on cerebrospinal fluid norepinephrine and corticotropin-releasing hormone concentrations in post-traumatic stress disorder.

PubMed

Geracioti, Thomas D; Baker, Dewleen G; Kasckow, John W; Strawn, Jeffrey R; Jeffrey Mulchahey, J; Dashevsky, Boris A; Horn, Paul S; Ekhator, Nosakhare N

2008-05-01

Although elevated concentrations of both corticotropin-releasing hormone (CRH) and norepinephrine are present in the cerebrospinal fluid (CSF) of patients with post-traumatic stress disorder (PTSD), the effects of exposure to traumatic stimuli on these stress-related hormones in CSF are unknown. A randomized, within-subject, controlled, cross-over design was used, in which patients with war-related PTSD underwent 6-h continuous lumbar CSF withdrawal on two occasions per patient (6-9 weeks apart). During one session the patients watched a 1-h film containing combat footage (traumatic film) and in the other a 1-h film on how to oil paint (neutral film). At 10-min intervals, we quantified CRH and norepinephrine in CSF, and ACTH and cortisol in plasma, before, during, and after symptom provocation. Subjective anxiety and mood were monitored using 100-mm visual analog scales. Blood pressure and heart rate were obtained every 10min from a left leg monitor. Eight of 10 patients completed two CSF withdrawal procedures each. A major drop in mood and increases in anxiety and blood pressure occurred during the traumatic relative to the neutral videotape. CSF norepinephrine rose during the traumatic film relative to the neutral videotape; this rise directly correlated with magnitude of mood drop. In contrast, CSF CRH concentrations declined during the trauma-related audiovisual stimulus, both absolutely and relative to the neutral stimulus; the magnitude of CRH decline correlated with degree of subjective worsening of anxiety level and mood. Plasma cortisol concentrations were lower and ACTH levels similar during the stress compared with the neutral videotape. CSF concentrations of the stress hormones norepinephrine and CRH differentially change after exposure to 1h of trauma-related audiovisual stimulation in chronic, combat-related PTSD. While the CSF norepinephrine increase was postulated, the decline in CSF CRH levels is surprising and could be due to audiovisual stress

Stress, interviewer support, and children's eyewitness identification accuracy.

PubMed

Rush, Elizabeth B; Quas, Jodi A; Yim, Ilona S; Nikolayev, Mariya; Clark, Steven E; Larson, Rakel P

2014-01-01

Few studies have investigated how stress affects eyewitness identification capabilities across development, and no studies have investigated whether retrieval context in conjunction with stress affects accuracy. In this study, one hundred fifty-nine 7- to 8- and 12- to 14-year-olds completed a high- or low-stress laboratory protocol during which they interacted with a confederate. Two weeks later, they attempted to identify the confederate in a photographic lineup. The lineup administrator behaved in either a supportive or a nonsupportive manner. Participants who experienced the high-stress event and were questioned by a supportive interviewer were most accurate in rejecting target-absent lineups. Results have implications for debates about effects of stress on eyewitness recall, how best to elicit accurate identifications in children, and developmental changes in episodic mnemonic processes. © 2013 The Authors. Child Development © 2013 Society for Research in Child Development, Inc.

The relationship between personality and the response to acute psychological stress.

PubMed

Xin, Yuanyuan; Wu, Jianhui; Yao, Zhuxi; Guan, Qing; Aleman, André; Luo, Yuejia

2017-12-04

The present study examined the relationship between personality traits and the response to acute psychological stress induced by a standardized laboratory stress induction procedure (the Trier Social Stress Test, TSST). The stress response was measured with a combination of cardiovascular reactivity, hypothalamic-pituitary-adrenal axis reactivity, and subjective affect (including positive affect, negative affect and subjective controllability) in healthy individuals. The Generalized Estimating Equations (GEE) approach was applied to account for the relationship between personality traits and stress responses. Results suggested that higher neuroticism predicted lower heart rate stress reactivity, lower cortisol stress response, more decline of positive affect and lower subjective controllability. Individuals higher in extraversion showed smaller cortisol activation to stress and less increase of negative affect. In addition, higher openness score was associated with lower cortisol stress response. These findings elucidate that neuroticism, extraversion and openness are important variables associated with the stress response and different dimensions of personality trait are associated with different aspects of the stress response.

Impact of trace metal concentrations on coccolithophore growth and morphology: laboratory simulations of Cretaceous stress

NASA Astrophysics Data System (ADS)

Faucher, Giulia; Hoffmann, Linn; Bach, Lennart T.; Bottini, Cinzia; Erba, Elisabetta; Riebesell, Ulf

2017-07-01

The Cretaceous ocean witnessed intervals of profound perturbations such as volcanic input of large amounts of CO2, anoxia, eutrophication and introduction of biologically relevant metals. Some of these extreme events were characterized by size reduction and/or morphological changes of a few calcareous nannofossil species. The correspondence between intervals of high trace metal concentrations and coccolith dwarfism suggests a negative effect of these elements on nannoplankton biocalcification processes in past oceans. In order to test this hypothesis, we explored the potential effect of a mixture of trace metals on growth and morphology of four living coccolithophore species, namely Emiliania huxleyi, Gephyrocapsa oceanica, Pleurochrysis carterae and Coccolithus pelagicus. The phylogenetic history of coccolithophores shows that the selected living species are linked to Mesozoic species showing dwarfism under excess metal concentrations. The trace metals tested were chosen to simulate the environmental stress identified in the geological record and upon known trace metal interactions with living coccolithophore algae.Our laboratory experiments demonstrated that elevated trace metal concentrations, similarly to the fossil record, affect coccolithophore algae size and/or weight. Smaller coccoliths were detected in E. huxleyi and C. pelagicus, while coccoliths of G. oceanica showed a decrease in size only at the highest trace metal concentrations. P. carterae coccolith size was unresponsive to changing trace metal concentrations. These differences among species allow discriminating the most- (P. carterae), intermediate- (E. huxleyi and G. oceanica) and least-tolerant (C. pelagicus) taxa. The fossil record and the experimental results converge on a selective response of coccolithophores to metal availability.These species-specific differences must be considered before morphological features of coccoliths are used to reconstruct paleo-chemical conditions.

Disordered eating behaviour is associated with blunted cortisol and cardiovascular reactions to acute psychological stress.

PubMed

Ginty, Annie T; Phillips, Anna C; Higgs, Suzanne; Heaney, Jennifer L J; Carroll, Douglas

2012-05-01

Research suggests a potential dysregulation of the stress response in individuals with bulimia nervosa. This study measured both cardiovascular and cortisol reactions to a standardised laboratory stress task in individuals identified as showing disordered eating behaviour to determine whether dysregulation of the stress response is characteristic of the two branches of the stress response system. Female students (N=455) were screened using two validated eating disorder questionnaires. Twelve women with disordered eating, including self-induced vomiting, and 12 healthy controls were selected for laboratory stress testing. Salivary cortisol and cardiovascular activity, via Doppler imaging and semi-automatic blood pressure monitoring, were measured at resting baseline and during and after exposure to a 10-min mental arithmetic stress task. Compared to controls the disordered eating group showed blunted cortisol, cardiac output, heart rate, and stroke volume reactions to the acute stress, as well as an attenuated vasodilatory reaction. These effects could not be accounted for in terms of group differences in stress task performance, subjective task impact/engagement, age, BMI, neuroticism, cardio-respiratory fitness, or co-morbid exercise dependence. Our findings suggest that disordered eating is characterised by a dysregulation of the autonomic stress-response system. As such, they add further weight to the general contention that blunted stress reactivity is characteristic of a number of maladaptive behaviours and states. Copyright © 2011 Elsevier Ltd. All rights reserved.

Notice of Release: 'Stress tolerant smooth bromegrass STSB'

USDA-ARS?s Scientific Manuscript database

The Agricultural Research Service, U.S. Department of Agriculture announces the release of a stress tolerant smooth bromegrass (STSB) [Bromus inermys, Leyss.] germplasm (PI xxxx) developed by Dr. Bryan K. Kindiger at the USDA-ARS Grazinglands Research Laboratory, El Reno, OK 73036. STSB is release...

Testing Plastic Deformations of Materials in the Introductory Undergraduate Mechanics Laboratory

ERIC Educational Resources Information Center

Romo-Kroger, C. M.

2012-01-01

Normally, a mechanics laboratory at the undergraduate level includes an experiment to verify compliance with Hooke's law in materials, such as a steel spring and an elastic rubber band. Stress-strain curves are found for these elements. Compression in elastic bands is practically impossible to achieve due to flaccidity. A typical experiment for…

Exposure to Acute Stress is Associated with Attenuated Sweet Taste

PubMed Central

al’Absi, Mustafa; Nakajima, Motohiro; Hooker, Stephanie; Wittmers, Larry; Cragin, Tiffany

2011-01-01

This study examined the effects of stress on taste perception. Participants (N = 38; 21 women) completed two laboratory sessions: one stress (public speaking, math, and cold pressor) and one control rest session. The taste perception test was conducted at the end of each session and included rating the intensity and pleasantness of sweet, salty, sour, and savory solutions at suprathreshold concentrations. Cardiovascular, hormonal, and mood measures were collected throughout the sessions. Participants showed the expected changes in cardiovascular, hormonal, and mood measures in response to stress. Reported intensity of the sweet solution was significantly lower on the stress day than on the rest day. Cortisol level post stress predicted reduced intensity of salt and sour, suggesting that stress-related changes in adrenocortical activity were related to reduced taste intensity. Results indicate that acute stress may alter taste perception, and ongoing research investigates the extent to which these changes mediate effects of stress on appetite. PMID:22091733

Enhanced emotional empathy after psychosocial stress in young healthy men.

PubMed

Wolf, Oliver T; Schulte, Judith M; Drimalla, Hanna; Hamacher-Dang, Tanja C; Knoch, Daria; Dziobek, Isabel

2015-01-01

Empathy is a core prerequisite for human social behavior. Relatively, little is known about how empathy is influenced by social stress and its associated neuroendocrine alterations. The current study was designed to test the impact of acute stress on emotional and cognitive empathy. Healthy male participants were exposed to a psychosocial laboratory stressor (trier social stress test, (TSST)) or a well-matched control condition (Placebo-TSST). Afterwards they participated in an empathy test measuring emotional and cognitive empathy (multifaceted empathy test, (MET)). Stress exposure caused an increase in negative affect, a rise in salivary alpha amylase and a rise in cortisol. Participants exposed to stress reported more emotional empathy in response to pictures displaying both positive and negative emotional social scenes. Cognitive empathy (emotion recognition) in contrast did not differ between the stress and the control group. The current findings provide initial evidence for enhanced emotional empathy after acute psychosocial stress.

Novel Monitoring Techniques for Characterizing Frictional Interfaces in the Laboratory

PubMed Central

Selvadurai, Paul A.; Glaser, Steven D.

2015-01-01

A pressure-sensitive film was used to characterize the asperity contacts along a polymethyl methacrylate (PMMA) interface in the laboratory. The film has structural health monitoring (SHM) applications for flanges and other precision fittings and train rail condition monitoring. To calibrate the film, simple spherical indentation tests were performed and validated against a finite element model (FEM) to compare normal stress profiles. Experimental measurements of the normal stress profiles were within −7.7% to 6.6% of the numerical calculations between 12 and 50 MPa asperity normal stress. The film also possessed the capability of quantifying surface roughness, an important parameter when examining wear and attrition in SHM applications. A high definition video camera supplied data for photometric analysis (i.e., the measure of visible light) of asperities along the PMMA-PMMA interface in a direct shear configuration, taking advantage of the transparent nature of the sample material. Normal stress over individual asperities, calculated with the pressure-sensitive film, was compared to the light intensity transmitted through the interface. We found that the luminous intensity transmitted through individual asperities linearly increased 0.05643 ± 0.0012 candelas for an increase of 1 MPa in normal stress between normal stresses ranging from 23 to 33 MPa. PMID:25923930

Stress tolerance and growth physiology of yeast strains from the Brazilian fuel ethanol industry.

PubMed

Della-Bianca, B E; Gombert, A K

2013-12-01

Improved biofuels production requires a better understanding of industrial microorganisms. Some wild Saccharomyces cerevisiae strains, isolated from the fuel ethanol industry in Brazil, present exceptional fermentation performance, persistence and prevalence in the harsh industrial environment. Nevertheless, their physiology has not yet been systematically investigated. Here we present a first systematic evaluation of the widely used industrial strains PE-2, CAT-1, BG-1 and JP1, in terms of their tolerance towards process-related stressors. We also analyzed their growth physiology under heat stress. These strains were evaluated in parallel to laboratory and baker's strains. Whereas the industrial strains performed in general better than the laboratory strains under ethanol or acetic acid stresses and on industrial media, high sugar stress was tolerated equally by all strains. Heat and low pH stresses clearly distinguished fuel ethanol strains from the others, indicating that these conditions might be the ones that mostly exert selective pressure on cells in the industrial environment. During shake-flask cultivations using a synthetic medium at 37 °C, industrial strains presented higher ethanol yields on glucose than the laboratory strains, indicating that they could have been selected for this trait-a response to energy-demanding fermentation conditions. These results might be useful to guide future improvements of large-scale fuel ethanol production via engineering of stress tolerance traits in other strains, and eventually also for promoting the use of these fuel ethanol strains in different industrial bioprocesses.

Emotions and eating. Self-reported and experimentally induced changes in food intake under stress.

PubMed

Wallis, D J; Hetherington, M M

2009-04-01

Two studies investigated the stress-eating relationship. The first examined self-reported changes in intake of snack foods, whilst the second investigated stress-induced overconsumption in a laboratory setting comparing high (HF) and low-fat (LF) snacks. Eighty-nine females completed the Dutch Eating Behaviour Questionnaire (DEBQ) [Van Strien, T., Fritjers, J. E. R., Bergers, G. P. A., & Defares, P. B. (1986). Dutch Eating Behaviour Questionnaire for assessment of restrained, emotional and external eating behaviour. International Journal of Eating Disorders, 5, 295-315] and a self-report measure designed to evaluate changes in eating in response to stress. Increased intake of HF snacks was associated with high emotional eating but not with restraint. A laboratory-based experiment compared intake of HF and LF snacks after ego-threatening and neutral Stroop colour-naming tasks. Intake was suppressed by 31.8% in restrained compared to unrestrained eaters across tasks. Restrained eaters consumed significantly less after ego-threat than after the neutral manipulation, but this was associated only with intake of the LF snack. Restrained eaters' intake of dried fruit was suppressed by 33.2% after ego-threat relative to the neutral task, despite a significant increase in hunger for this group following ego-threat. These results suggest that the type and variety of foods offered influences the link between stress and eating in laboratory settings. Further research should aim to replicate and extend these findings, with a view to informing potential interventions for stress-related eating.

On the expected relationships among apparent stress, static stress drop, effective shear fracture energy, and efficiency

USGS Publications Warehouse

Beeler, N.M.; Wong, T.-F.; Hickman, S.H.

2003-01-01

We consider expected relationships between apparent stress ??a and static stress drop ????s using a standard energy balance and find ??a = ????s (0.5 - ??), where ?? is stress overshoot. A simple implementation of this balance is to assume overshoot is constant; then apparent stress should vary linearly with stress drop, consistent with spectral theories (Brune, 1970) and dynamic crack models (Madariaga, 1976). Normalizing this expression by the static stress drop defines an efficiency ??sw = ??sa/????s as follows from Savage and Wood (1971). We use this measure of efficiency to analyze data from one of a number of observational studies that find apparent stress to increase with seismic moment, namely earthquakes recorded in the Cajon Pass borehole by Abercrombie (1995). Increases in apparent stress with event size could reflect an increase in seismic efficiency; however, ??sw for the Cajon earthquakes shows no such increase and is approximately constant over the entire moment range. Thus, apparent stress and stress drop co-vary, as expected from the energy balance at constant overshoot. The median value of ??sw for the Cajon earthquakes is four times lower than ??sw for laboratory events. Thus, these Cajon-recorded earthquakes have relatively low and approximately constant efficiency. As the energy balance requires ??sw = 0.5 - ??, overshoot can be estimated directly from the Savage-Wood efficiency; overshoot is positive for Cajon Pass earthquakes. Variations in apparent stress with seismic moment for these earthquakes result primarily from systematic variations in static stress drop with seismic moment and do not require a relative decrease in sliding resistance with increasing event size (dynamic weakening). Based on the comparison of field and lab determinations of the Savage-Wood efficiency, we suggest the criterion ??sw > 0.3 as a test for dynamic weakening in excess of that seen in the lab.

Earthquake mechanism and predictability shown by a laboratory fault

USGS Publications Warehouse

King, C.-Y.

1994-01-01

Slip events generated in a laboratory fault model consisting of a circulinear chain of eight spring-connected blocks of approximately equal weight elastically driven to slide on a frictional surface are studied. It is found that most of the input strain energy is released by a relatively few large events, which are approximately time predictable. A large event tends to roughen stress distribution along the fault, whereas the subsequent smaller events tend to smooth the stress distribution and prepare a condition of simultaneous criticality for the occurrence of the next large event. The frequency-size distribution resembles the Gutenberg-Richter relation for earthquakes, except for a falloff for the largest events due to the finite energy-storage capacity of the fault system. Slip distributions, in different events are commonly dissimilar. Stress drop, slip velocity, and rupture velocity all tend to increase with event size. Rupture-initiation locations are usually not close to the maximum-slip locations. ?? 1994 Birkha??user Verlag.

Attempting to bridge the gap between laboratory and seismic estimates of fracture energy

USGS Publications Warehouse

McGarr, A.; Fletcher, Joe B.; Beeler, N.M.

2004-01-01

To investigate the behavior of the fracture energy associated with expanding the rupture zone of an earthquake, we have used the results of a large-scale, biaxial stick-slip friction experiment to set the parameters of an equivalent dynamic rupture model. This model is determined by matching the fault slip, the static stress drop and the apparent stress. After confirming that the fracture energy associated with this model earthquake is in reasonable agreement with corresponding laboratory values, we can use it to determine fracture energies for earthquakes as functions of stress drop, rupture velocity and fault slip. If we take account of the state of stress at seismogenic depths, the model extrapolation to larger fault slips yields fracture energies that agree with independent estimates by others based on dynamic rupture models for large earthquakes. For fixed stress drop and rupture speed, the fracture energy scales linearly with fault slip.

Implementation science: the laboratory as a command centre.

PubMed

Boeras, Debrah I; Nkengasong, John N; Peeling, Rosanna W

2017-03-01

Recent advances in point-of-care technologies to ensure universal access to affordable quality-assured diagnostics have the potential to transform patient management, surveillance programmes, and control of infectious diseases. Decentralization of testing can put tremendous stresses on fragile health systems if the laboratory is not involved in the planning, introduction, and scale-up strategies. The impact of investments in novel technologies can only be realized if these tests are evaluated, adopted, and scaled up within the healthcare system with appropriate planning and understanding of the local contexts in which these technologies will be used. In this digital age, the laboratory needs to take on the role of the Command Centre for technology introduction and implementation. Implementation science is needed to understand the political, cultural, economic, and behavioural context for technology introduction. The new paradigm should include: building a comprehensive system of laboratories and point-of-care testing sites to provide quality-assured diagnostic services with good laboratory-clinic interface to build trust in test results and linkage to care; building and coordinating a comprehensive national surveillance and communication system for disease control and global health emergencies; conducting research to monitor the impact of new tools and interventions on improving patient care.

ROLE OF ENVIRONMENTAL HEAT AND COLD STRESS ON THE PHYSIOLOGICAL RESPONSE TO ORGANOPHOSPHATES AND OTHER TOXICANTS.

EPA Science Inventory

Most toxicological and pharmacological studies are performed in laboratory rodents maintained under comfortable environmental conditions. However, exposure to toxicants as well as some drugs can occur under stressful conditions during rest or while exercising. Heat stress can exa...

Induction of the cellular stress response in Chironomus (Diptera)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pardalis, G.; Hudson, L.A.; Ciborowski, J.J.H.

1995-12-31

The accumulation of stress or heat shock proteins is involved in the protection and defense of a cell from environmentally induced damage. Under stressful conditions, cytoplasmic stress protein 70 migrates to the nucleus where it assists in the restoration of the nucleolar function. The authors have demonstrated a dose-response relationship between incidence of decreased nucleolar size in chironomid salivary glands and degree of sediment contamination. Reduced nucleolar size is indicative of reduced nucleolar function. The relationship between nucleolus size and stress protein accumulation is being explored. They are conducting experiments on chironomids to characterize the response elicited by heat shockmore » and PAH exposure in the laboratory to determine if the simultaneous action of more than one stressor can significantly alter the stress response. Simultaneous studies are being conducted to validate these biomarkers in mesocosm caging experiments. Aspects of the response will be useful as biomarkers of general stress.« less

Placing the Mnemonic Model in Context: Diagnostic, Theoretical, and Clinical Considerations

ERIC Educational Resources Information Center

Monroe, Scott M.; Mineka, Susan

2008-01-01

The mnemonic model of posttraumatic stress disorder (PTSD) proposed by D. C. Rubin, D. Berntsen, and M. K. Bohni presents some provocative and potentially insightful ideas about this mental disorder. D. C. Rubin et al. suggested that PTSD is caused and maintained through a "pathogenic memory" (D. C. Rubin et al., 2008, p. 985) of a negative event…

Laboratories | NREL

Science.gov Websites

| Z A Accelerated Exposure Testing Laboratory Advanced Optical Materials Laboratory Advanced Thermal Laboratory Structural Testing Laboratory Surface Analysis Laboratory Systems Performance Laboratory T Thermal Storage Materials Laboratory Thermal Storage Process and Components Laboratory Thin-Film Deposition

Cyclotron in the Materials and Stresses Building

NASA Image and Video Library

1976-11-21

Researchers check the cyclotron in the Materials and Stresses Building at the National Aeronautics and Space Administration (NASA) Lewis Research Center. The Materials and Stresses Building, built in 1949, contained a number of laboratories to test the strength, diffusion, and other facets of materials. The materials could be subjected to high temperatures, high stresses, corrosion, irradiation, and hot gasses. The Physics of Solids Laboratory included a cyclotron, cloud chamber, helium cryostat, and metallurgy cave. The cyclotron was built in the early 1950s to test the effects of radiation on different materials so that the proper materials could be used to construct a nuclear aircraft engine and other components. By the late 1950s, the focus had shifted to similar studies for rockets. NASA cancelled its entire nuclear program in January 1973, and the cyclotron was mothballed. In 1975 the Cleveland Clinic Foundation partnered with NASA Lewis to use the cyclotron to treat cancer patients with a new type of radiation therapy. The cyclotron split beryllium atoms which caused neutrons to be released. The neutrons were streamed directly at the patient’s tumor. Over the course of five years, the cyclotron was used to treat 1200 patients. The program was terminated in 1980 as the Clinic shifted its efforts to concentrate on non-radiation treatments. The Lewis cyclotron was mothballed for a number of years before being demolished.

Modeling perceived stress via HRV and accelerometer sensor streams.

PubMed

Wu, Min; Cao, Hong; Nguyen, Hai-Long; Surmacz, Karl; Hargrove, Caroline

2015-08-01

Discovering and modeling of stress patterns of human beings is a key step towards achieving automatic stress monitoring, stress management and healthy lifestyle. As various wearable sensors become popular, it becomes possible for individuals to acquire their own relevant sensory data and to automatically assess their stress level on the go. Previous studies for stress analysis were conducted in the controlled laboratory and clinic settings. These studies are not suitable for stress monitoring in one's daily life as various physical activities may affect the physiological signals. In this paper, we address such issue by integrating two modalities of sensors, i.e., HRV sensors and accelerometers, to monitor the perceived stress levels in daily life. We gathered both the heart and the motion data from 8 participants continuously for about 2 weeks. We then extracted features from both sensory data and compared the existing machine learning methods for learning personalized models to interpret the perceived stress levels. Experimental results showed that Bagging classifier with feature selection is able to achieve a prediction accuracy 85.7%, indicating our stress monitoring on daily basis is fairly practical.

Exposure to acute stress is associated with attenuated sweet taste.

PubMed

Al'Absi, Mustafa; Nakajima, Motohiro; Hooker, Stephanie; Wittmers, Larry; Cragin, Tiffany

2012-01-01

This study examined the effects of stress on taste perception. Participants (N = 38; 21 women) completed two laboratory sessions: one stress (public speaking, math, and cold pressor) and one control rest session. The taste perception test was conducted at the end of each session and included rating the intensity and pleasantness of sweet, salty, sour, and savory solutions at suprathreshold concentrations. Cardiovascular, hormonal, and mood measures were collected throughout the sessions. Participants showed the expected changes in cardiovascular, hormonal, and mood measures in response to stress. Reported intensity of the sweet solution was significantly lower on the stress day than on the rest day. Cortisol level poststress predicted reduced intensity of salt and sour, suggesting that stress-related changes in adrenocortical activity were related to reduced taste intensity. Results indicate that acute stress may alter taste perception, and ongoing research investigates the extent to which these changes mediate effects of stress on appetite. Copyright © 2011 Society for Psychophysiological Research.

Procedure for Adaptive Laboratory Evolution of Microorganisms Using a Chemostat.

PubMed

Jeong, Haeyoung; Lee, Sang J; Kim, Pil

2016-09-20

Natural evolution involves genetic diversity such as environmental change and a selection between small populations. Adaptive laboratory evolution (ALE) refers to the experimental situation in which evolution is observed using living organisms under controlled conditions and stressors; organisms are thereby artificially forced to make evolutionary changes. Microorganisms are subject to a variety of stressors in the environment and are capable of regulating certain stress-inducible proteins to increase their chances of survival. Naturally occurring spontaneous mutations bring about changes in a microorganism's genome that affect its chances of survival. Long-term exposure to chemostat culture provokes an accumulation of spontaneous mutations and renders the most adaptable strain dominant. Compared to the colony transfer and serial transfer methods, chemostat culture entails the highest number of cell divisions and, therefore, the highest number of diverse populations. Although chemostat culture for ALE requires more complicated culture devices, it is less labor intensive once the operation begins. Comparative genomic and transcriptome analyses of the adapted strain provide evolutionary clues as to how the stressors contribute to mutations that overcome the stress. The goal of the current paper is to bring about accelerated evolution of microorganisms under controlled laboratory conditions.

Changes in ST, QT and RR ECG intervals during acute stress in firefighters: a pilot study.

PubMed

Paiva, Joana S; Rodrigues, Susana; Cunha, Joao Paulo Silva

2016-08-01

Firefighting is a stressful occupation. The monitoring of psychophysiological measures in those professionals can be a way to prevent and early detect cardiac diseases and other stress-related problems. The current study aimed to assess morphological changes in the ECG signal induced by acute stress. A laboratory protocol was conducted among 6 firefighters, including a laboratory stress-inducer task - the Trier Social Stress Task (TSST) - and a 2-choice reaction time task (CRTT) that was performed before (CRTT1) and after (CRTT2) the stress condition. ECG signals were continuously acquired using the VitalJacket®, a wearable t-shirt that acts as a medical certified ECG monitor. Results showed that ECG morphological features such as QT and ST intervals are able to differentiate stressful from non stressful events in first responders. Group mean Visual Analogue Scale (VAS) for stress assessment significantly increased after the stress task (TSST), relatively to the end of CRTT2 (after TSST: 4.67±1.63; after CRTT2: 3.17±0.75), a change that was accompanied by a significant increase in group mean QT and ST segments corrected for heart rate during TSST. These encouraging results will be followed by larger studies in order to explore those measures and its physiological impact under realistic environments in a higher scalability.

Deep focus earthquakes in the laboratory

NASA Astrophysics Data System (ADS)

Schubnel, Alexandre; Brunet, Fabrice; Hilairet, Nadège; Gasc, Julien; Wang, Yanbin; Green, Harry W., II

2014-05-01

While the existence of deep earthquakes have been known since the 1920's, the essential mechanical process responsible for them is still poorly understood and remained one of the outstanding unsolved problems of geophysics and rock mechanics. Indeed, deep focus earthquake occur in an environment fundamentally different from that of shallow (<100 km) earthquakes. As pressure and temperature increase with depth however, intra-crystalline plasticity starts to dominate the deformation regime so that rocks yield by plastic flow rather than by brittle fracturing. Olivine phase transitions have provided an attractive alternative mechanism for deep focus earthquakes. Indeed, the Earth mantle transition zone (410-700km) is the locus of the two successive polymorphic transitions of olivine. Such scenario, however, runs into the conceptual barrier of initiating failure in a pressure (P) and temperature (T) regime where deviatoric stress relaxation is expected to be achieved through plastic flow. Here, we performed laboratory deformation experiments on Germanium olivine (Mg2GeO4) under differential stress at high pressure (P=2-5GPa) and within a narrow temperature range (T=1000-1250K). We find that fractures nucleate at the onset of the olivine to spinel transition. These fractures propagate dynamically (i.e. at a non-negligible fraction of the shear wave velocity) so that intense acoustic emissions are generated. Similar to deep-focus earthquakes, these acoustic emissions arise from pure shear sources, and obey the Gutenberg-Richter law without following Omori's law. Microstructural observations prove that dynamic weakening likely involves superplasticity of the nanocrystalline spinel reaction product at seismic strain rates. Although in our experiments the absolute stress value remains high compared to stresses expected within the cold core of subducted slabs, the observed stress drops are broadly consistent with those calculated for deep earthquakes. Constant differential

Using HeLa cell stress response to introduce first year students to the scientific method, laboratory techniques, primary literature, and scientific writing.

PubMed

Resendes, Karen K

2015-01-01

Incorporating scientific literacy into inquiry driven research is one of the most effective mechanisms for developing an undergraduate student's strength in writing. Additionally, discovery-based laboratories help develop students who approach science as critical thinkers. Thus, a three-week laboratory module for an introductory cell and molecular biology course that couples inquiry-based experimental design with extensive scientific writing was designed at Westminster College to expose first year students to these concepts early in their undergraduate career. In the module students used scientific literature to design and then implement an experiment on the effect of cellular stress on protein expression in HeLa cells. In parallel the students developed a research paper in the style of the undergraduate journal BIOS to report their results. HeLa cells were used to integrate the research experience with the Westminster College "Next Chapter" first year program, in which the students explored the historical relevance of HeLa cells from a sociological perspective through reading The Immortal Life of Henrietta Lacks by Rebecca Skloot. In this report I detail the design, delivery, student learning outcomes, and assessment of this module, and while this exercise was designed for an introductory course at a small primarily undergraduate institution, suggestions for modifications at larger universities or for upper division courses are included. Finally, based on student outcomes suggestions are provided for improving the module to enhance the link between teaching students skills in experimental design and execution with developing student skills in information literacy and writing. © 2015 The International Union of Biochemistry and Molecular Biology.

Measuring behavior in mice with chronic stress depression paradigm.

PubMed

Strekalova, Tatyana; Steinbusch, Harry W M

2010-03-17

Many studies with chronic stress, a common depression paradigm, lead to inconsistent behavioral results. We are introducing a new model of stress-induced anhedonia, which provides more reproducible induction and behavioral measuring of depressive-like phenotype in mice. First, a 4-week stress procedure induces anhedonia, defined by decreased sucrose preference, in the majority of but not all C57BL/6 mice. The remaining 30-50% non-anhedonic animals are used as an internal control for stress effects that are unrelated to anhedonia. Next, a modified sucrose test enables the detection of inter-individual differences in mice. Moreover, testing under dimmed lighting precludes behavioral artifacts caused by hyperlocomotion, a major confounding factor in stressed mice. Finally, moderation of the stress load increases the reproducibility of anhedonia induction, which otherwise is difficult to provide because of inter-batch variability in laboratory mice. We believe that our new mouse model overcomes some major difficulties in measuring behavior with chronic stress depression models. Copyright 2009 Elsevier Inc. All rights reserved.

Observations of fault zone heterogeneity effects on stress alteration and slip nucleation during a fault reactivation experiment in the Mont Terri rock laboratory, Switzerland

NASA Astrophysics Data System (ADS)

Nussbaum, C.; Guglielmi, Y.

2016-12-01

The FS experiment at the Mont Terri underground research laboratory consists of a series of controlled field stimulation tests conducted in a fault zone intersecting a shale formation. The Main Fault is a secondary order reverse fault that formed during the creation of the Jura fold-and-thrust belt, associated to a large décollement. The fault zone is up to 6 m wide, with micron-thick shear zones, calcite veins, scaly clay and clay gouge. We conducted fluid injection tests in 4 packed-off borehole intervals across the Main Fault using mHPP probes that allow to monitor 3D displacement between two points anchored to the borehole walls at the same time as fluid pressure and flow rate. While pressurizing the intervals above injection pressures of 3.9 to 5.3 MPa, there is an irreversible change in the displacements magnitude and orientation associated to the hydraulic opening of natural shear planes oriented N59 to N69 and dipping 39 to 58°. Displacements of 0.01 mm to larger than 0.1 mm were captured, the highest value being observed at the interface between the low permeable fault core and the damage zone. Contrasted fault movements were observed, mainly dilatant in the fault core, highly dilatant-normal slip at the fault core-damage zone interface and low dilatant-strike-slip-reverse in the damage-to-intact zones. First using a slip-tendency approach based on Coulomb reactivation potential of fault planes, we computed a stress tensor orientation for each test. The input parameters are the measured displacement vectors above the hydraulic opening pressure and the detailed fault geometry of each intervals. All measurements from the damage zone can be explained by a stress tensor in strike-slip regime. Fault movements measured at the core-damage zone interface and within the fault core are in agreement with the same stress orientations but changed as normal faulting, explaining the significant dilatant movements. We then conducted dynamic hydromechanical simulations

Intra-individual psychological and physiological responses to acute laboratory stressors of different intensity.

PubMed

Skoluda, Nadine; Strahler, Jana; Schlotz, Wolff; Niederberger, Larissa; Marques, Sofia; Fischer, Susanne; Thoma, Myriam V; Spoerri, Corinne; Ehlert, Ulrike; Nater, Urs M

2015-01-01

The phenomenon of stress is understood as a multidimensional concept which can be captured by psychological and physiological measures. There are various laboratory stress protocols which enable stress to be investigated under controlled conditions. However, little is known about whether these protocols differ with regard to the induced psycho-physiological stress response pattern. In a within-subjects design, 20 healthy young men underwent four of the most common stress protocols (Stroop test [Stroop], cold pressor test [CPT], Trier Social Stress Test [TSST], and bicycle ergometer test [Ergometer]) and a no-stress control condition (rest) in a randomized order. For the multidimensional assessment of the stress response, perceived stress, endocrine and autonomic biomarkers (salivary cortisol, salivary alpha-amylase, and heart rate) were obtained during the experiments. All stress protocols evoked increases in perceived stress levels, with the highest levels in the TSST, followed by Ergometer, Stroop, and CPT. The highest HPA axis response was found in the TSST, followed by Ergometer, CPT, and Stroop, whilst the highest autonomic response was found in the Ergometer, followed by TSST, Stroop, and CPT. These findings suggest that different stress protocols differentially stimulate various aspects of the stress response. Physically demanding stress protocols such as the Ergometer test appear to be particularly suitable for evoking autonomic stress responses, whereas uncontrollable and social-evaluative threatening stressors (such as the TSST) are most likely to elicit HPA axis stress responses. The results of this study may help researchers in deciding which stress protocol to use, depending on the individual research question. Copyright © 2014 Elsevier Ltd. All rights reserved.

Mechanisms and rates of strength recovery in laboratory fault zones

NASA Astrophysics Data System (ADS)

Muhuri, Sankar Kumar

2001-07-01

The life cycle of a typical fault zone consists of repeated catastrophic seismic events during which much of the slip is accommodated interspersed with creep during the inter-seismic cycle. Fault strength is regenerated during this period as a result of several time-dependent, fluid assisted deformation mechanisms that are favored by high stresses along active fault zones. The strengthening is thought to be a function of the sum total of the rates of recovery due to these multiple creep processes as well as the rate of tectonic loading. Mechanisms and rates of strength recovery in laboratory fault zones were investigated in this research with the aid of several experimental designs. It was observed that wet faults recover strength in a time-dependent manner after slip due to operative creep processes. Subsequent loading results in unstable failure of a cohesive gouge zone with large associated stress drops. The failure process is similar to that observed for intact rocks. Dry laboratory faults in contrast do not recover strength and slip along them is always stable with no observable drop in stress. Strengthening in laboratory faults proceeds in a manner that is a logarithmic function of time. The recovery is attributable to fluid mediated mechanisms such as pressure solution, crack sealing and Ostwald ripening that collectively cause a reduction in porosity and enhance lithification of an unconsolidated gouge. Rates for the individual deformation mechanisms investigated in separate experimental setups were also observed to be a non-linear function of time. Pressure solution and Ostwald ripening are especially enhanced due to the significant volume fraction of fine particles within the gouge created due to cataclasis during slip. The results of this investigation may be applied to explain observations of rapid strengthening along large, active crustal fault zones such as parts of the San Andreas Fault system in California and the Nojima fault in Japan. Presence of

A fluid response: Alpha-amylase reactions to acute laboratory stress are related to sample timing and saliva flow rate.

PubMed

Nagy, Tamás; van Lien, René; Willemsen, Gonneke; Proctor, Gordon; Efting, Marieke; Fülöp, Márta; Bárdos, György; Veerman, Enno C I; Bosch, Jos A

2015-07-01

Salivary alpha-amylase (sAA) is used as a sympathetic (SNS) stress marker, though its release is likely co-determined by SNS and parasympathetic (PNS) activation. The SNS and PNS show asynchronous changes during acute stressors, and sAA responses may thus vary with sample timing. Thirty-four participants underwent an eight-minute memory task (MT) and cold pressor task (CPT). Cardiovascular SNS (pre-ejection period, blood pressure) and PNS (heart rate variability) activity were monitored continuously. Unstimulated saliva was collected repeatedly during and after each laboratory stressor, and sAA concentration (U/ml) and secretion (U/minute) determined. Both stressors increased anxiety. The MT caused an immediate and continued cardiac SNS activation, but sAA concentration increased at task cessation only (+54%); i.e., when there was SNS-PNS co-activation. During the MT sAA secretion even decreased (-35%) in conjunction with flow rate and vagal tone. The CPT robustly increased blood pressure but not sAA. In summary, sAA fluctuations did not parallel changes in cardiac SNS activity or anxiety. sAA responses seem contingent on sample timing and flow rate, likely involving both SNS and PNS influences. Verification using other stressors and contexts seems warranted. Copyright © 2015 Elsevier B.V. All rights reserved.

Distinct hip and rearfoot kinematics in female runners with a history of tibial stress fracture.

PubMed

Milner, Clare E; Hamill, Joseph; Davis, Irene S

2010-02-01

Cross-sectional controlled laboratory study. To investigate the kinematics of the hip, knee, and rearfoot in the frontal and transverse planes in female distance runners with a history of tibial stress fracture. Tibial stress fractures are a common overuse injury in runners, accounting for up to half of all stress fractures. Abnormal kinematics of the lower extremity may contribute to abnormal musculoskeletal load distributions, leading to an increased risk of stress fractures. Thirty female runners with a history of tibial stress fracture were compared to 30 age-matched and weekly-running-distance-matched control subjects with no previous lower extremity bony injuries. Kinematic and kinetic data were collected using a motion capture system and a force platform, respectively, as subjects ran in the laboratory. Selected variables of interest were compared between the groups using a multivariate analysis of variance (MANOVA). Peak hip adduction and peak rearfoot eversion angles were greater in the stress fracture group compared to the control group. Peak knee adduction and knee internal rotation angles and all joint angles at impact peak were similar between the groups. Runners with a previous tibial stress fracture exhibited greater peak hip adduction and rearfoot eversion angles during the stance phase of running compared to healthy controls. A consequence of these mechanics may be altered load distribution within the lower extremity, predisposing individuals to stress fracture.

Cognitive emotion regulation fails the stress test

PubMed Central

Raio, Candace M.; Orederu, Temidayo A.; Palazzolo, Laura; Shurick, Ashley A.; Phelps, Elizabeth A.

2013-01-01

Cognitive emotion regulation has been widely shown in the laboratory to be an effective way to alter the nature of emotional responses. Despite its success in experimental contexts, however, we often fail to use these strategies in everyday life where stress is pervasive. The successful execution of cognitive regulation relies on intact executive functioning and engagement of the prefrontal cortex, both of which are rapidly impaired by the deleterious effects of stress. Because it is specifically under stressful conditions that we may benefit most from such deliberate forms of emotion regulation, we tested the efficacy of cognitive regulation after stress exposure. Participants first underwent fear-conditioning, where they learned that one stimulus (CS+) predicted an aversive outcome but another predicted a neutral outcome (CS−). Cognitive regulation training directly followed where participants were taught to regulate fear responses to the aversive stimulus. The next day, participants underwent an acute stress induction or a control task before repeating the fear-conditioning task using these newly acquired regulation skills. Skin conductance served as an index of fear arousal, and salivary α-amylase and cortisol concentrations were assayed as neuroendocrine markers of stress response. Although groups showed no differences in fear arousal during initial fear learning, nonstressed participants demonstrated robust fear reduction following regulation training, whereas stressed participants showed no such reduction. Our results suggest that stress markedly impairs the cognitive regulation of emotion and highlights critical limitations of this technique to control affective responses under stress. PMID:23980142

Laboratory studies in ultraviolet solar physics

NASA Technical Reports Server (NTRS)

Parkinson, W. H.; Kohl, J. L.; Gardner, L. D.; Raymond, J. C.; Smith, P. L.

1991-01-01

The research activity comprised the measurement of basic atomic processes and parameters which relate directly to the interpretation of solar ultraviolet observations and to the development of comprehensive models of the component structures of the solar atmosphere. The research was specifically directed towards providing the relevant atomic data needed to perform and to improve solar diagnostic techniques which probe active and quiet portions of the solar chromosphere, the transition zone, the inner corona, and the solar wind acceleration regions of the extended corona. The accuracy with which the physical conditions in these structures can be determined depends directly on the accuracy and completeness of the atomic and molecular data. These laboratory data are used to support the analysis programs of past and current solar observations (e.g., the Orbiting solar Observatories, the Solar Maximum Mission, the Skylab Apollo Telescope Mount, and the Naval Research Laboratory's rocket-borne High Resolution Telescope and Spectrograph). In addition, we attempted to anticipate the needs of future space-borne solar studies such as from the joint ESA/NASA Solar and Heliospheric Observatory (SOHO) spacecraft. Our laboratory activities stressed two categories of study: (1) the measurement of absolute rate coefficients for dielectronic recombination and electron impact excitation; and (2) the measurement of atomic transition probabilities for solar density diagnostics. A brief summary of the research activity is provided.

What is eating you? Stress and the drive to eat.

PubMed

Groesz, Lisa M; McCoy, Shannon; Carl, Jenna; Saslow, Laura; Stewart, Judith; Adler, Nancy; Laraia, Barbara; Epel, Elissa

2012-04-01

Non-human animal studies demonstrate relationships between stress and selective intake of palatable food. In humans, exposure to laboratory stressors and self-reported stress are associated with greater food intake. Large studies have yet to examine chronic stress exposure and eating behavior. The current study assessed the relationship between stress (perceived and chronic), drive to eat, and reported food frequency intake (nutritious food vs. palatable non-nutritious food) in women ranging from normal weight to obese (N=457). Greater reported stress, both exposure and perception, was associated with indices of greater drive to eat-including feelings of disinhibited eating, binge eating, hunger, and more ineffective attempts to control eating (rigid restraint; r's from .11 to .36, p's<.05). These data suggest that stress exposure may lead to a stronger drive to eat and may be one factor promoting excessive weight gain. Relationships between stress and eating behavior are of importance to public health given the concurrent increase in reported stress and obesity rates. Copyright © 2011 Elsevier Ltd. All rights reserved.

Neutrophil infiltration is implicated in the sustained thermal hyperalgesic response evoked by allergen provocation in actively sensitized rats.

PubMed

Lavich, Tatiana Ramos; Siqueira, Rodrigo de Azeredo; Farias-Filho, Francisco Alves; Cordeiro, Renato Sérgio Balão; Rodrigues e Silva, Patrícia Machado; Martins, Marco Aurélio

2006-11-01

It has been proposed that allergen provocation induces hyperalgesia but the involvement of immunoglobulin E and leukocytes remains poorly understood. Here, we have compared the profile of allergen-evoked thermal hyperalgesic response in both passively and actively sensitized rats, and investigated the role of leukocytes in allergen-evoked nociception. Wistar rats were passively sensitized with an intraplantar injection of immunoglobulin E anti-dinitrophenylated bovine serum albumin monoclonal antibody (0.5 microg/paw), and challenged with dinitrophenylated bovine serum albumin (0.5 microg/paw) 24 h later. Alternatively, the animals were actively sensitized with a mixture of Al(OH)3 and ovalbumin and challenged intraplantarly with ovalbumin (12 microg/paw) 14 days later. We found that the thermal hyperalgesic responses set in very rapidly and with comparable intensity in both passively and actively sensitized rats. However, while in the former group the response was shorter, peaking within 1 h and reducing thereafter, a marked plateau was observed from 1 to 6 h post-challenge in the latter group. Actively sensitized rats also had higher neutrophil influx in the plantar tissue, as attested by both myeloperoxidase activity and histological analysis. Treatment of actively sensitized rats with either fucoidin (10 mg/kg, i.v) or anti-rat neutrophil antiserum (i.p.) reduced neutrophil accumulation and the late hyperalgesic response noted from 3 to 6 h post-challenge. Thus, we conclude that though immunoglobulin E-mediated mechanisms can cause thermal hyperalgesia, components of the cellular immune reaction are crucial in order to amplify and sustain the immediate hyperalgesic response triggered by allergen, in a process dependent on neutrophil recruitment.

Stress Wave Source Characterization: Impact, Fracture, and Sliding Friction

NASA Astrophysics Data System (ADS)

McLaskey, Gregory Christofer

Rapidly varying forces, such as those associated with impact, rapid crack propagation, and fault rupture, are sources of stress waves which propagate through a solid body. This dissertation investigates how properties of a stress wave source can be identified or constrained using measurements recorded at an array of sensor sites located far from the source. This methodology is often called the method of acoustic emission and is useful for structural health monitoring and the noninvasive study of material behavior such as friction and fracture. In this dissertation, laboratory measurements of 1--300 mm wavelength stress waves are obtained by means of piezoelectric sensors which detect high frequency (10 kHz--3MHz) motions of a specimen's surface, picometers to nanometers in amplitude. Then, stress wave source characterization techniques are used to study ball impact, drying shrinkage cracking in concrete, and the micromechanics of stick-slip friction of Poly(methyl methacrylate) (PMMA) and rock/rock interfaces. In order to quantitatively relate recorded signals obtained with an array of sensors to a particular stress wave source, wave propagation effects and sensor distortions must be accounted for. This is achieved by modeling the physics of wave propagation and transduction as linear transfer functions. Wave propagation effects are precisely modeled by an elastodynamic Green's function, sensor distortion is characterized by an instrument response function, and the stress wave source is represented with a force moment tensor. These transfer function models are verified though calibration experiments which employ two different mechanical calibration sources: ball impact and glass capillary fracture. The suitability of the ball impact source model, based on Hertzian contact theory, is experimentally validated for small (˜1 mm) balls impacting massive plates composed of four different materials: aluminum, steel, glass, and PMMA. Using this transfer function approach

Familial Risk for Insomnia Is Associated With Abnormal Cortisol Response to Stress.

PubMed

Drake, Christopher L; Cheng, Philip; Almeida, David M; Roth, Thomas

2017-10-01

Abnormalities in the stress system have been implicated in insomnia. However, studies examining physiological stress regulation in insomnia have not consistently detected differences in the hypothalamic-pituitary-adrenal (HPA)-axis response to stress. One explanation may be that deficits in the stress system are associated specifically with a biological vulnerability to insomnia rather than the phenotypic expression of insomnia. To examine stress response as a function of vulnerability to insomnia, this study tested response to the Trier Social Stress Test in a sample of healthy sleepers with varying familial risks for insomnia. Thirty-five healthy individuals with and without familial risk for insomnia were recruited to complete a laboratory stressor. Participants with one or both biological parents with insomnia were categorized as positive for familial risk, whereas those without biological parents with insomnia were categorized as negative for familial risk. Participants completed the Trier Social Stress Test in the laboratory, and psychological and physiological (autonomic and HPA-axis) responses were compared. Despite self-reported increases in anxiety, those positive for familial risk exhibited a blunted cortisol response relative to those without familial risk for insomnia. Individuals with blunted cortisol also reported heightened reactivity to personal life stressors, including increased sleep disturbances, elevated cognitive intrusions, and more behavioral avoidance. Findings from this study provide initial evidence that abnormal stress regulation may be a biological predisposing factor conferred via familial risk for insomnia. This deficit may also predict negative consequences over time, including insomnia and the associated psychiatric comorbidities. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

Whole-body cortisol response of zebrafish to acute net handling stress

USGS Publications Warehouse

Ramsay, J.M.; Feist, G.W.; Varga, Z.M.; Westerfield, M.; Kent, M.L.; Schreck, C.B.

2009-01-01

Zebrafish, Danio rerio, are frequently handled during husbandry and experimental procedures in the laboratory, yet little is known about the physiological responses to such stressors. We measured the whole-body cortisol levels of adult zebrafish subjected to net stress and air exposure at intervals over a 24 h period; cortisol recovered to near control levels by about 1 h post-net-stress (PNS). We then measured cortisol at frequent intervals over a 1 h period. Cortisol levels were more than 2-fold higher in net stressed fish at 3 min PNS and continued to increase peaking at 15 min PNS, when cortisol levels were 6-fold greater than the control cortisol. Mean cortisol declined from 15 to 60 min PNS, and at 60 min, net-stressed cortisol was similar to control cortisol. Because the age of fish differed between studies, we examined resting cortisol levels of fish of different ages (3, 7, 13, and 19 months). The resting cortisol values among tanks with the same age fish differed significantly but there was no clear effect of age. Our study is the first to report the response and recovery of cortisol after net handling for laboratory-reared zebrafish. ?? 2009 Elsevier B.V.

Coral ontogeny affects early symbiont acquisition in laboratory-reared recruits

NASA Astrophysics Data System (ADS)

McIlroy, Shelby E.; Coffroth, Mary Alice

2017-09-01

In most coral species, the critical association with a subset of genetically diverse algal endosymbionts, Symbiodinium, is re-established anew each generation in early coral ontogeny. Yet little is known about the window during which these associations are established or the potential for altering symbiont associations through early exposure to non-native, and/or ecologically beneficial (e.g., stress tolerant), symbiont strains. This study examined the ontogenetic window of symbiont uptake in a restoration target species. Orbicella faveolata recruits, maintained aposymbiotic in laboratory tanks for 4 months, showed a significant decrease in symbiont acquisition upon exposure to natural seawater. Recruits initially inoculated with cultured Symbiodinium readily acquired additional strains from environmental symbiont populations upon exposure, but exogenous uptake also decreased in frequency after 4 months of laboratory rearing. Early exposure to Symbiodinium may benefit laboratory-reared recruits (e.g., enhance growth), but the potential for establishing long-term novel symbiotic associations may be limited.

Texture analysis at neutron diffractometer STRESS-SPEC

NASA Astrophysics Data System (ADS)

Brokmeier, H.-G.; Gan, W. M.; Randau, C.; Völler, M.; Rebelo-Kornmeier, J.; Hofmann, M.

2011-06-01

In response to the development of new materials and the application of materials and components in advanced technologies, non-destructive measurement methods of textures and residual stresses have gained worldwide significance in recent years. The materials science neutron diffractometer STRESS-SPEC at FRM II (Garching, Germany) is designed to be applied equally to texture and residual stress analyses by virtue of its very flexible configuration. Due to the high penetration capabilities of neutrons and the high neutron flux of STRESS-SPEC it allows a combined analysis of global texture, local texture, strain pole figure and FWHM pole figure in a wide variety of materials including metals, alloys, composites, ceramics and geological materials. Especially, the analysis of texture gradients in bulk materials using neutron diffraction has advantages over laboratory X-rays and EBSD for many scientific cases. Moreover, neutron diffraction is favourable for coarse-grained materials, where bulk information averaged over texture inhomogeneities is needed, and also stands out due to easy sample preparation. In future, the newly developed robot system for STRESS-SPEC will allow much more flexibility than an Eulerian cradle as on standard instruments. Five recent measurements are shown to demonstrate the wide range of possible texture applications at STRESS-SPEC diffractometer.

Differential effects of social stress on laboratory-based decision-making are related to both impulsive personality traits and gender.

PubMed

Wise, Richard J; Phung, Alissa L; Labuschagne, Izelle; Stout, Julie C

2015-01-01

Urgency is the tendency to make impulsive decisions under extreme positive or negative emotional states. Stress, gender and impulsive personality traits are all known to influence decision-making, but no studies have examined the interplay of all of these factors. We exposed 78 men and women to a stress or a non-stress condition, and then administered the Balloon Analogue Risk Task. We found that stress effects varied as a function of gender and urgency traits. Under stress, women low in negative urgency and men high in negative urgency made fewer risky decisions. Positive urgency yielded a similar pattern. Thus, decisions under stress depend on a complex interplay between gender and impulsive personality traits. These findings have implications for clinical disorders, such as substance use disorders, in which there are known deficits in decision-making and high levels of impulsive traits.

The role of eye fixation in memory enhancement under stress - An eye tracking study.

PubMed

Herten, Nadja; Otto, Tobias; Wolf, Oliver T

2017-04-01

In a stressful situation, attention is shifted to potentially relevant stimuli. Recent studies from our laboratory revealed that participants stressed perform superior in a recognition task involving objects of the stressful episode. In order to characterize the role of a stress induced alteration in visual exploration, the present study investigated whether participants experiencing a laboratory social stress situation differ in their fixation from participants of a control group. Further, we aimed at shedding light on the relation of fixation behaviour with obtained memory measures. We randomly assigned 32 male and 31 female participants to a control or a stress condition consisting of the Trier Social Stress Test (TSST), a public speaking paradigm causing social evaluative threat. In an established 'friendly' control condition (f-TSST) participants talk to a friendly committee. During both conditions, the committee members used ten office items (central objects) while another ten objects were present without being used (peripheral objects). Participants wore eye tracking glasses recording their fixations. On the next day, participants performed free recall and recognition tasks involving the objects present the day before. Stressed participants showed enhanced memory for central objects, accompanied by longer fixation times and larger fixation amounts on these objects. Contrasting this, fixation towards the committee faces showed the reversed pattern; here, control participants exhibited longer fixations. Fixation indices and memory measures were, however, not correlated with each other. Psychosocial stress is associated with altered fixation behaviour. Longer fixation on objects related to the stressful situation may reflect enhanced encoding, whereas diminished face fixation suggests gaze avoidance of aversive, socially threatening stimuli. Modified visual exploration should be considered in future stress research, in particular when focussing on memory for a

Criteria for Selecting Types of Foreign-Language Laboratory Systems. ERIC Focus Reports on the Teaching of Foreign Languages, Number 20.

ERIC Educational Resources Information Center

Hutchinson, Joseph C.; Hutchinson, June O.

Focusing on the current status of the language laboratory in instructional use, this report stresses the need to employ a systems approach in the selection and operation of laboratory equipment. The author points out the interrelatedness of the key factors in any system, including: (1) people, (2) method, (3) instructional materials, (4)…

Effects of post-encoding stress on performance in the DRM false memory paradigm.

PubMed

Pardilla-Delgado, Enmanuelle; Alger, Sara E; Cunningham, Tony J; Kinealy, Brian; Payne, Jessica D

2016-01-01

Numerous studies have investigated how stress impacts veridical memory, but how stress influences false memory formation remains poorly understood. In order to target memory consolidation specifically, a psychosocial stress (TSST) or control manipulation was administered following encoding of 15 neutral, semantically related word lists (DRM false memory task) and memory was tested 24 h later. Stress decreased recognition of studied words, while increasing false recognition of semantically related lure words. Moreover, while control subjects remembered true and false words equivalently, stressed subjects remembered more false than true words. These results suggest that stress supports gist memory formation in the DRM task, perhaps by hindering detail-specific processing in the hippocampus. © 2015 Pardilla-Delgado et al.; Published by Cold Spring Harbor Laboratory Press.

Residual Stresses and Other Properties of Teardrops

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stroud, Mary Ann; Veirs, Douglas Kirk; Berg, John M.

The Department of Energy’s 3013 Standard for packaging plutonium-bearing materials for storage up to fifty years specifies a minimum of two individually welded, nested containers herein referred to as the 3013 outer and the 3013 inner.1 Stress corrosion cracking (SCC) is a potential failure mechanism for 3013 inner containers.2,3 The bagless transfer container (BTC), a 3013 inner container used by Hanford and Savanna River Site (SRS) made from 304L stainless steel (SS), poses the greatest concern for SCC.4,5 The Surveillance and Monitoring Program (SMP) use stressed metal samples known as teardrops as screening tools in SCC studies to evaluate factorsmore » that could result in cracks in the 3013 containers.6,7 This report provides background information on the teardrops used in the Los Alamos National Laboratory (LANL) SMP studies including method of construction, composition and variability. In addition, the report discusses measurements of residual stresses in teardrops and compares the results with residual stresses in BTCs reported previously.4 Factors affecting residual stresses, including teardrop dimensions and surface finish, are also discussed.« less

Contribution of job strain, job status and marital status to laboratory and ambulatory blood pressure in patients with mild hypertension.

PubMed

Blumenthal, J A; Thyrum, E T; Siegel, W C

1995-02-01

The effects of job strain, occupational status, and marital status on blood pressure were evaluated in 99 men and women with mild hypertension. Blood pressure was measured during daily life at home and at work over 15 h of ambulatory blood pressure monitoring. On a separate day, blood pressure was measured in the laboratory during mental stress testing. As expected, during daily life, blood pressure was higher at work than at home. High job strain was associated with elevated systolic blood pressure among women, but not men. However, both men and women with high status occupations had significantly higher blood pressures during daily life and during laboratory mental stress testing. This was especially true for men, in that men with high job status had higher systolic blood pressures than low job status men. Marital status also was an important moderating variable, particularly for women, with married women having higher ambulatory blood pressures than single women. During mental stress testing, married persons had higher systolic blood pressures than unmarried individuals. These data suggest that occupational status and marital status may contribute even more than job strain to variations in blood pressure during daily life and laboratory testing.

Process and Learning Outcomes from Remotely-Operated, Simulated, and Hands-on Student Laboratories

ERIC Educational Resources Information Center

Corter, James E.; Esche, Sven K.; Chassapis, Constantin; Ma, Jing; Nickerson, Jeffrey V.

2011-01-01

A large-scale, multi-year, randomized study compared learning activities and outcomes for hands-on, remotely-operated, and simulation-based educational laboratories in an undergraduate engineering course. Students (N = 458) worked in small-group lab teams to perform two experiments involving stress on a cantilever beam. Each team conducted the…

Dynamics of yield-stress droplets: Morphology of impact craters

NASA Astrophysics Data System (ADS)

Neufeld, Jerome; Sohr, David; Ferrari, Leo; Dalziel, Stuart

2017-11-01

Yield strength can play an important role for the dynamics of droplets impacting on surfaces, whether at the industrial or planetary scale, and can capture a zoo of impact crater morphologies, from simple parabolic craters, to more complex forms with forms with, for example, multiple rings, central peaks. Here we show that the morphology of planetary impact craters can be reproduced in the laboratory using carbopol, a transparent yield-stress fluid, as both impactor and bulk fluid. Using high-speed video photography, we characterise the universal, transient initial excavation stage of impact and show the dependence of the subsequent relaxation to final crater morphology on impactor size, impact speed and yield stress. To further interrogate our laboratory impacts, we dye our impactor to map its final distribution and use particle tracking to determine the flow fields during impact and the maximal extent of the yield surface. We characterise the flow-fields induced during impact, and the maximal extent of the yield surface, by tracking particles within the bulk fluid and map the distribution of impactor and bulk by tracing the final distribution of dyed impactor. The results of laboratory impact droplets are used to infer the properties of planetary impactors, and aid in inter.

Do Daughters Really Cause Divorce? Stress, Pregnancy, and Family Composition

PubMed Central

Hamoudi, Amar; Nobles, Jenna

2014-01-01

Provocative studies have reported that in the United States, marriages producing firstborn daughters are more likely to divorce than those producing firstborn sons. The findings have been interpreted as contemporary evidence of fathers' son preference. Our study explores the potential role of another set of dynamics that may drive these patterns: namely, selection into live birth. Epidemiological evidence indicates that the characteristic female survival advantage may begin before birth. If stress accompanying unstable marriages has biological effects on fecundity, a female survival advantage could generate an association between stability and the sex composition of offspring. Combining regression and simulation techniques to analyze real-world data, we ask, How much of the observed association between sex of the firstborn child and risk of divorce could plausibly be accounted for by the joint effects of female survival advantage and reduced fecundity associated with unstable marriage? Using data from the National Longitudinal Survey of Youth (NLSY79), we find that relationship conflict predicts the sex of children born after conflict was measured; conflict also predicts subsequent divorce. Conservative specification of parameters linking pregnancy characteristics, selection into live birth, and divorce are sufficient to generate a selection-driven association between offspring sex and divorce, which is consequential in magnitude. Our findings illustrate the value of demographic accounting of processes which occur before birth—a period when many outcomes of central interest in the population sciences begin to take shape. PMID:25024115

Do daughters really cause divorce? Stress, pregnancy, and family composition.

PubMed

Hamoudi, Amar; Nobles, Jenna

2014-08-01

Provocative studies have reported that in the United States, marriages producing firstborn daughters are more likely to divorce than those producing firstborn sons. The findings have been interpreted as contemporary evidence of fathers' son preference. Our study explores the potential role of another set of dynamics that may drive these patterns: namely, selection into live birth. Epidemiological evidence indicates that the characteristic female survival advantage may begin before birth. If stress accompanying unstable marriages has biological effects on fecundity, a female survival advantage could generate an association between stability and the sex composition of offspring. Combining regression and simulation techniques to analyze real-world data, we ask, How much of the observed association between sex of the firstborn child and risk of divorce could plausibly be accounted for by the joint effects of female survival advantage and reduced fecundity associated with unstable marriage? Using data from the National Longitudinal Survey of Youth (NLSY79), we find that relationship conflict predicts the sex of children born after conflict was measured; conflict also predicts subsequent divorce. Conservative specification of parameters linking pregnancy characteristics, selection into live birth, and divorce are sufficient to generate a selection-driven association between offspring sex and divorce, which is consequential in magnitude. Our findings illustrate the value of demographic accounting of processes which occur before birth-a period when many outcomes of central interest in the population sciences begin to take shape.

The Social Dimension of Stress: Experimental Manipulations of Social Support and Social Identity in the Trier Social Stress Test

PubMed Central

Frisch, Johanna U.; Häusser, Jan A.; van Dick, Rolf; Mojzisch, Andreas

2015-01-01

In many situations humans are influenced by the behavior of other people and their relationships with them. For example, in stressful situations supportive behavior of other people as well as positive social relationships can act as powerful resources to cope with stress. In order to study the interplay between these variables, this protocol describes two effective experimental manipulations of social relationships and supportive behavior in the laboratory. In the present article, these two manipulations are implemented in the Trier Social Stress Test (TSST)—a standard stress induction paradigm in which participants are subjected to a simulated job interview. More precisely, we propose (a) a manipulation of the relationship between different protagonists in the TSST by making a shared social identity salient and (b) a manipulation of the behavior of the TSST-selection committee, which acts either supportively or unsupportively. These two experimental manipulations are designed in a modular fashion and can be applied independently of each other but can also be combined. Moreover, these two manipulations can also be integrated into other stress protocols and into other standardized social interactions such as trust games, negotiation tasks, or other group tasks. PMID:26649856

A commercially available immunoglobulin E-based test for food allergy gives inconsistent results in healthy ponies.

PubMed

Dupont, S; De Spiegeleer, A; Liu, D J X; Lefère, L; van Doorn, D A; Hesta, M

2016-01-01

Commercial immunoglobulin E (IgE)-based tests are available for diagnosis of food allergies and are commonly used in equine practice. However, these tests have been proven unreliable as a screening method in man and other species, but not critically evaluated in equids. Therefore, a commercially available IgE-based test for horses was evaluated. To evaluate the consistency of the results obtained with a commercially available IgE-based test for food allergy diagnosis in ponies (Phase I) and to subject ponies to a provocation trial with the presumed allergens (Phase II). Allergen screening followed by experimental food provocation trials in healthy ponies. Blood samples of 17 healthy Shetland ponies were taken at 2 different time points, sent blinded to a commercial laboratory for screening of common food allergens and the results were evaluated for consistency (Phase I). Ponies that were positive for food allergens were consecutively challenged orally with each allergen separately for 14 days (Phase II). A washout period of one week was applied in ponies with multiple positive results. Clinical parameters and serum amyloid A were monitored during the provocation trial. Only 7/17 ponies were negative on the IgE-based test at the 2 time points, 3 had positive results twice but only one tested positive twice for the same food allergen. No abnormalities were noted during the provocation trials. This study demonstrated that this IgE-based test is not a reliable screening tool for food allergy in healthy equids. © 2015 EVJ Ltd.

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

PubMed

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

2018-08-01

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

Acute stress affects prospective memory functions via associative memory processes.

PubMed

Szőllősi, Ágnes; Pajkossy, Péter; Demeter, Gyula; Kéri, Szabolcs; Racsmány, Mihály

2018-01-01

Recent findings suggest that acute stress can improve the execution of delayed intentions (prospective memory, PM). However, it is unclear whether this improvement can be explained by altered executive control processes or by altered associative memory functioning. To investigate this issue, we used physical-psychosocial stressors to induce acute stress in laboratory settings. Then participants completed event- and time-based PM tasks requiring the different contribution of control processes and a control task (letter fluency) frequently used to measure executive functions. According to our results, acute stress had no impact on ongoing task performance, time-based PM, and verbal fluency, whereas it enhanced event-based PM as measured by response speed for the prospective cues. Our findings indicate that, here, acute stress did not affect executive control processes. We suggest that stress affected event-based PM via associative memory processes. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of self-fertilization, environmental stress and exposure to xenobiotics on fitness-related traits of the freshwater snail Lymnaea stagnalis.

PubMed

Coutellec, Marie-Agnès; Lagadic, Laurent

2006-03-01

Genetic and ecological factors may interact in their effects on fitness. Such interactions are thus to be expected between inbreeding and exposure of a population to a toxicant. The magnitude of inbreeding depression is thought to increase in stressful environments. To test this hypothesis, we investigated the combined effects of environmental conditions and inbreeding on fitness in the self-fertile snail Lymnaea stagnalis, using a stress gradient (0-2) applied to a 100 isolated and paired lineages: laboratory control (0), outdoor microcosm control (1) and pesticide exposure under outdoor microcosm conditions (2). Outdoor stress conditions were maintained for 28 days prior to measurements of fitness traits (fecundity, hatching success, and size at hatching) under laboratory conditions, so that delayed environmental effects could be estimated. Under laboratory control conditions, we found significant initial family level heterogeneity for most measured traits, including physiological performances as assessed through energetic biomarkers. Whatever the environmental conditions, inbreeding depression was very low for progeny performances. Negative values of self-fertilization depression (SFD) were obtained. Unexpectedly, SFD showed a negative relationship with the assumed stress intensity, reflecting a higher sensitivity under pairing than under selfing, mostly due to parental fecundity. This suggests that stressful conditions may favour selfing. Stress intensity increased the distribution limits of both depression indices, suggesting that changes in fitness are less predictable in a population under stress. Implications of such findings for environmental risk assessment of pesticides are discussed.

Evaluation of AIS Data for Agronomic and Rangeland Vegetation: Preliminary Results for August 1984 Flight over Nebraska Sandhills Agricultural Laboratory

NASA Technical Reports Server (NTRS)

Blad, B. L.; Starks, P. J.; Hays, C.; Gardner, B. R.

1985-01-01

Since 1978 scientists from the Center for Agricultural Meteorology and Climatology at the University of Nebraska have been conducting research at the Sandhills Agricultural Laboratory on the effects of water stress on crop growth, development and yield using remote sensing techniques. We have been working to develop techniques, both remote and ground-based, to monitor water stress, phenological development, leaf area, phytomass production and grain yields of corn, soybeans and sorghum. Because of the sandy soils and relatively low rainfall at the site it is an excellent location to study water stress without the necessity of installing expensive rainout shelters. The primary objectives of research with the airborne imaging spectrometer (AIS) data collected during an August 1984 flight over the Sandhills Agricultural Laboratory are to evaluate the potential of using AIS to: (1) discriminate crop type; (2) to detect subtle architectural differences that exist among different cultivars or hybrids of agronomic crops; (3) to detect and quantify, if possible, the level of water stress imposed on the crops; and (4) to evaluate leaf area and biomass differences for different crops.

A Simple Student Laboratory on Osmotic Flow, Osmotic Pressure, and the Reflection Coefficient.

ERIC Educational Resources Information Center

Feher, Joseph J.; Ford, George D.

1995-01-01

Describes a laboratory exercise containing a practical series of experiments that novice students can perform within two hours. The exercise provides a confirmation of van't Hoff's law while placing more emphasis on osmotic flow than pressure. Students can determine parameters such as the reflection coefficient which stress the interaction of both…

ANFO Response to Low-Stress Planar Impacts

NASA Astrophysics Data System (ADS)

Cooper, Marcia; Trott, Wayne; Schmitt, Robert; Short, Mark; Jackson, Scott

2011-06-01

Ammonium Nitrate plus Fuel Oil (ANFO) is a non-ideal explosive where the mixing behavior of the mm-diameter prills with the absorbed fuel oil is of critical importance for chemical energy release. The large-scale heterogeneity of ANFO establishes conditions uniquely suitable for observation using the spatially- and temporally-resolved line-imaging ORVIS (optically recording velocity interferometer system) diagnostic. The first demonstration of transmitted wave profiles in ANFO from low-stress planar impacts using a single-stage gas gun is reported. The experimental stresses simulate the compressive wave conditions preceding detonation providing insight into dominant mesoscale processes. Distributions of particle velocity as related to mean prill diameters and observations of between-prill jetting are reported. Use of the measured distributions of particle velocity for collaboration with mesoscale model development and the statistically-averaged values for contribution to continuum model development is discussed. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Hyperosmotic Stress Response of Campylobacter jejuni

PubMed Central

Cameron, Andrew; Frirdich, Emilisa; Huynh, Steven; Parker, Craig T.

2012-01-01

The diarrheal pathogen Campylobacter jejuni and other gastrointestinal bacteria encounter changes in osmolarity in the environment, through exposure to food processing, and upon entering host organisms, where osmotic adaptation can be associated with virulence. In this study, growth profiles, transcriptomics, and phenotypic, mutant, and single-cell analyses were used to explore the effects of hyperosmotic stress exposure on C. jejuni. Increased growth inhibition correlated with increased osmotic concentration, with both ionic and nonionic stressors inhibiting growth at 0.620 total osmol liter−1. C. jejuni adaptation to a range of osmotic stressors and concentrations was accompanied by severe filamentation in subpopulations, with microscopy indicating septum formation and phenotypic diversity between individual cells in a filament. Population heterogeneity was also exemplified by the bifurcation of colony morphology into small and large variants on salt stress plates. Flow cytometry of C. jejuni harboring green fluorescent protein (GFP) fused to the ATP synthase promoter likewise revealed bimodal subpopulations under hyperosmotic stress. We also identified frequent hyperosmotic stress-sensitive variants within the clonal wild-type population propagated on standard laboratory medium. Microarray analysis following hyperosmotic upshift revealed enhanced expression of heat shock genes and genes encoding enzymes for synthesis of potential osmoprotectants and cross-protective induction of oxidative stress genes. The capsule export gene kpsM was also upregulated, and an acapsular mutant was defective for growth under hyperosmotic stress. For C. jejuni, an organism lacking most conventional osmotic response factors, these data suggest an unusual hyperosmotic stress response, including likely “bet-hedging” survival strategies relying on the presence of stress-fit individuals in a heterogeneous population. PMID:22961853

Perceived social support predicts lower cardiovascular reactivity to stress in older adults.

PubMed

Howard, Siobhán; Creaven, Ann-Marie; Hughes, Brian M; O'Leary, Éanna D; James, Jack E

2017-04-01

The benefits of perceived social support for physical and psychological health are well-established. However, little research has explored associations between perceived social support and cardiovascular reactivity in older adults. This exploratory study recruited a sample of older adults (M age =69years, SD=5.62) and examined quality and quantity of perceived social support as predictors of cardiovascular reactivity to laboratory-based stress (N=39 participants) and ambulatory cardiovascular activity in everyday life (n=28). The results suggest that quality, but not quantity, of perceived social support predicts reduced blood pressure reactivity to stress in the laboratory. Although quality of support was not associated with ambulatory blood pressure, results suggest that quantity of daily social support may be associated with higher ambulatory heart rate, but not with social contact during measurement. This preliminary study extends prior work on social support and cardiovascular function to a group of older adults in both laboratory and field settings. Challenges for much-needed future research in this area are discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

A new momentum integral method for approximating bed shear stress

NASA Astrophysics Data System (ADS)

Wengrove, M. E.; Foster, D. L.

2016-02-01

In nearshore environments, accurate estimation of bed stress is critical to estimate morphologic evolution, and benthic mass transfer fluxes. However, bed shear stress over mobile boundaries in wave environments is notoriously difficult to estimate due to the non-equilibrium boundary layer. Approximating the friction velocity with a traditional logarithmic velocity profile model is common, but an unsteady non-uniform flow field violates critical assumptions in equilibrium boundary layer theory. There have been several recent developments involving stress partitioning through an examination of the momentum transfer contributions that lead to improved estimates of the bed stress. For the case of single vertical profile observations, Mehdi et al. (2014) developed a full momentum integral-based method for steady-unidirectional flow that integrates the streamwise Navier-Stokes equation three times to an arbitrary position within the boundary layer. For the case of two-dimensional velocity observations, Rodriguez-Abudo and Foster (2014) were able to examine the momentum contributions from waves, turbulence and the bedform in a spatial and temporal averaging approach to the Navier-Stokes equations. In this effort, the above methods are combined to resolve the bed shear stress in both short and long wave dominated environments with a highly mobile bed. The confluence is an integral based approach for determining bed shear stress that makes no a-priori assumptions of boundary layer shape and uses just a single velocity profile time series for both the phase dependent case (under waves) and the unsteady case (under solitary waves). The developed method is applied to experimental observations obtained in a full scale laboratory investigation (Oregon State's Large Wave Flume) of the nearbed velocity field over a rippled sediment bed in oscillatory flow using both particle image velocimetry and a profiling acoustic Doppler velocimeter. This method is particularly relevant for

Stress appraisals and cellular aging: A key role for anticipatory threat in the relationship between psychological stress and telomere length

PubMed Central

O’Donovan, Aoife; Tomiyama, A. Janet; Lin, Jue; Puterman, Eli; Adler, Nancy E.; Kemeny, Margaret; Wolkowitz, Owen M.; Blackburn, Elizabeth H.; Epel, Elissa S.

2012-01-01

Chronic psychological stressis a risk factor formultiple diseases of aging. Accelerated cellular aging as indexed by short telomere length has emerged as a potential common biological mechanism linking various forms of psychological stress and diseases of aging. Stress appraisals determine the degree and type of biological stress responses and altered stress appraisals may be a common psychological mechanism linking psychological stress and diseases of aging. However, no previous studies have examined the relationship between stress appraisals and telomere length. We exposed chronically stressed female caregivers and non-caregiving controls (N= 50; M age = 62.14±6.10) to a standardized acute laboratory stressor and measured their anticipatory and retrospective threat and challenge appraisals of the stressor. We hypothesized that threat and challenge appraisals would be associated with shorter and longer telomere length respectively, and that chronic care giving stress would influence telomere length through altered stress appraisals. Higher anticipatory threat appraisals were associated with shorter age-adjusted telomere length (β = −.32, p = .03), but challenge appraisals and retrospective threat appraisals showed no independent association with telomere length. Caregivers reported significantly higher anticipatory (β = −.36, p = .006)and retrospective (β = −.29, p = .03) threat appraisals than controls, but similar challenge appraisals. Although there was no significant main effect of caregiver status on telomere length, care giving had a significant indirect effect on telomere length through anticipatory threat appraisals. Exaggerated anticipatory threat appraisals may be a common and modifiable psychological mechanism of psychological stress effects on cellular aging. PMID:22293459

Provocation 6

ERIC Educational Resources Information Center

Mathematics Teaching, 2009

2009-01-01

In this article, two old men make the link: real mathematics = functional mathematics. The two old men were referred to as Alpha and Beta. Alpha talks about the problem in so many schools, now, and that they have teachers who have either forgotten how to engage learners or who have never experienced the power. Beta speaks of a plague on teachers'…

Multilinear stress-strain and failure calibrations for Ti-6Al-4V.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Corona, Edmundo

This memo concerns calibration of an elastic-plastic J 2 material model for Ti-6Al-4V (grade 5) alloy based on tensile uniaxial stress-strain data obtained in the laboratory. In addition, tension tests on notched specimens provided data to calibrate two ductile failure models: Johnson-Cook and Wellman's tearing parameter. The tests were conducted by Kim Haulen- beek and Dave Johnson (1528) in the Structural Mechanics Laboratory (SML) during late March and early April, 2017. The SML EWP number was 4162. The stock material was a TIMETALR® 6-4 Titanium billet with 9 in. by 9 in. square section and length of 137 in. Themore » product description indicates that it was a forging delivered in annealed condition (2 hours @ 1300oF, AC at the mill). The tensile mechanical properties reported in the material certi cation are given in Table 1, where σ o represents the 0.2% strain offset yield stress, σ u the ultimate stress, ε f the elongation at failure and R.A. the reduction in area.« less

Developing a Virtual Rock Deformation Laboratory

NASA Astrophysics Data System (ADS)

Zhu, W.; Ougier-simonin, A.; Lisabeth, H. P.; Banker, J. S.

2012-12-01

Experimental rock physics plays an important role in advancing earthquake research. Despite its importance in geophysics, reservoir engineering, waste deposits and energy resources, most geology departments in U.S. universities don't have rock deformation facilities. A virtual deformation laboratory can serve as an efficient tool to help geology students naturally and internationally learn about rock deformation. Working with computer science engineers, we built a virtual deformation laboratory that aims at fostering user interaction to facilitate classroom and outreach teaching and learning. The virtual lab is built to center around a triaxial deformation apparatus in which laboratory measurements of mechanical and transport properties such as stress, axial and radial strains, acoustic emission activities, wave velocities, and permeability are demonstrated. A student user can create her avatar to enter the virtual lab. In the virtual lab, the avatar can browse and choose among various rock samples, determine the testing conditions (pressure, temperature, strain rate, loading paths), then operate the virtual deformation machine to observe how deformation changes physical properties of rocks. Actual experimental results on the mechanical, frictional, sonic, acoustic and transport properties of different rocks at different conditions are compiled. The data acquisition system in the virtual lab is linked to the complied experimental data. Structural and microstructural images of deformed rocks are up-loaded and linked to different deformation tests. The integration of the microstructural image and the deformation data allows the student to visualize how forces reshape the structure of the rock and change the physical properties. The virtual lab is built using the Game Engine. The geological background, outstanding questions related to the geological environment, and physical and mechanical concepts associated with the problem will be illustrated on the web portal. In

Only in the Language Laboratory: Dynamic Stress Matching as an Aid to the Development of Listening Comprehension.

ERIC Educational Resources Information Center

Vanderplank, Robert N.

1980-01-01

An experiment was carried out at the University of Edinburgh to discover ways in which students might be helped to understand spoken language and to become more confident in their interactions in the language. As a result of the experiment findings, materials were designed to train students to perceive stress patterns, to internalize stress-timing…

Synergistic Effect of High Charge and Energy Particle Radiation and Chronological Age on Biomarkers of Oxidative Stress and Tissue Degeneration: A Ground-Based Study Using the Vertebrate Laboratory Model Organism Oryzias latipes

PubMed Central

Zheng, Xuan; Zhang, Xinyan; Ding, Lingling; Lee, Jeffrey R.; Weinberger, Paul M.; Dynan, William S.

2014-01-01

High charge and energy (HZE) particles are a main hazard of the space radiation environment. Uncertainty regarding their health effects is a limiting factor in the design of human exploration-class space missions, that is, missions beyond low earth orbit. Previous work has shown that HZE exposure increases cancer risk and elicits other aging-like phenomena in animal models. Here, we investigate how a single exposure to HZE particle radiation, early in life, influences the subsequent age-dependent evolution of oxidative stress and appearance of degenerative tissue changes. Embryos of the laboratory model organism, Oryzias latipes (Japanese medaka fish), were exposed to HZE particle radiation at doses overlapping the range of anticipated human exposure. A separate cohort was exposed to reference γ-radiation. Survival was monitored for 750 days, well beyond the median lifespan. The population was also sampled at intervals and liver tissue was subjected to histological and molecular analysis. HZE particle radiation dose and aging contributed synergistically to accumulation of lipid peroxidation products, which are a marker of chronic oxidative stress. This was mirrored by a decline in PPARGC1A mRNA, which encodes a transcriptional co-activator required for expression of oxidative stress defense genes and for mitochondrial maintenance. Consistent with chronic oxidative stress, mitochondria had an elongated and enlarged ultrastructure. Livers also had distinctive, cystic lesions. Depending on the endpoint, effects of γ-rays in the same dose range were either lesser or not detected. Results provide a quantitative and qualitative framework for understanding relative contributions of HZE particle radiation exposure and aging to chronic oxidative stress and tissue degeneration. PMID:25375139

Synergistic Effect of High Charge and Energy Particle Radiation and Chronological Age on Biomarkers of Oxidative Stress and Tissue Degeneration: A Ground-Based Study Using the Vertebrate Laboratory Model Organism Oryzias latipes

DOE PAGES

Zheng, Xuan; Zhang, Xinyan; Ding, Lingling; ...

2014-11-06

High charge and energy (HZE) particles are a main hazard of the space radiation environment. Uncertainty regarding their health effects is a limiting factor in the design of human exploration-class space missions, that is, missions beyond low earth orbit. Previous work has shown that HZE exposure increases cancer risk and elicits other aging-like phenomena in animal models. Here, we investigate how a single exposure to HZE particle radiation, early in life, influences the subsequent age-dependent evolution of oxidative stress and appearance of degenerative tissue changes. Embryos of the laboratory model organism, Oryzias latipes (Japanese medaka fish), were exposed to HZEmore » particle radiation at doses overlapping the range of anticipated human exposure. A separate cohort was exposed to reference γ-radiation. Survival was monitored for 750 days, well beyond the median lifespan. The population was also sampled at intervals and liver tissue was subjected to histological and molecular analysis. HZE particle radiation dose and aging contributed synergistically to accumulation of lipid peroxidation products, which are a marker of chronic oxidative stress. This was mirrored by a decline in PPARGC1A mRNA, which encodes a transcriptional co-activator required for expression of oxidative stress defense genes and for mitochondrial maintenance. Consistent with chronic oxidative stress, mitochondria had an elongated and enlarged ultrastructure. Livers also had distinctive, cystic lesions. Depending on the endpoint, effects of γ-rays in the same dose range were either lesser or not detected. Results provide a quantitative and qualitative framework for understanding relative contributions of HZE particle radiation exposure and aging to chronic oxidative stress and tissue degeneration.« less

Neurohemodynamic Correlates of Washing Symptoms in Obsessive-compulsive Disorder: A Pilot fMRI Study Using Symptom Provocation Paradigm.

PubMed

Agarwal, Sri Mahavir; Jose, Dania; Baruah, Upasana; Shivakumar, Venkataram; Kalmady, Sunil Vasu; Venkatasubramanian, Ganesan; Mataix-Cols, David; Reddy, Yemmigannur Chandrashekhar Janardhan

2013-01-01

Obsessive-compulsive disorder (OCD) is increasingly being viewed as a multidimensional heterogeneous disorder caused due to the dysfunction of several closely related, overlapping frontostriatal circuits. A study investigating the dimensional construct in treatment naïve, co-morbidity free patients with identical handedness is likely to provide the necessary homogeneity and power to elicit neural correlates of the various symptom dimensions, and overcome the limitations of previous studies. Nine DSM-IV OCD patients with predominant contamination-related obsessive-compulsive symptoms (age=29.8±7.1 years; five males: four females; years-of-education=13.9±1.6, YBOCS total score=28.8±4.7, DYBOCS Contamination dimension score=10.7±1.8) and nine healthy controls matched one to one with the patients for age, sex, and years of education (age=27.8±5.4, five males: four females; years-of-education=14.9±3.0), were examined during symptom provocation task performance in 3TMRI. Paired samples t test of brain activation differences (contamination relevant pictures - neutral pictures), limited to apriori regions of interest was done using SPM8 (uncorrected P<0.005). Patients found significantly more pictures to be anxiety provoking in comparison to healthy controls. Patients were found to have deficient activation in the following areas in comparison with healthy controls: bilateral anterior prefrontal, dorsolateral prefrontal, orbitofrontal, anterior cingulate, insular and parietal cortices, precuneus, and caudate. Results underscore the importance of frontal, striatal, parietal, and occipital areas in the pathophysiology of OCD. Divergence of findings from previous studies might be attributed to the absence of confounding factors in the current study and may be due to production of intense anxiety in patients.

Adenosine monophosphate is not superior to histamine for bronchial provocation test for assessment of asthma control and symptoms.

PubMed

Wu, Fan; Guan, Wei-Jie; Gao, Yi; An, Jia-Ying; Xie, Yan-Qing; Liu, Wen-Ting; Yu, Xin-Xin; Zheng, Jin-Ping

2017-07-01

Adenosine monophosphate (AMP) may reflect airway inflammation and hyperresponsiveness, but relationship between AMP and histamine (His, a conventional stimulus) bronchial provocation test (BPT) in asthma is not fully elucidated. To compare both BPTs and determine their utility in reflecting changes of asthmatic symptoms. BPTs were performed in a cross-over fashion, at 2-4 day intervals. Cumulative doses eliciting 20% FEV 1 fall (PD 20 FEV 1 ), diagnostic performance and adverse events (AEs) were compared. Patients with PD 20 FEV 1 lower than geometric mean were defined as responders, otherwise poor responders. Patients with uncontrolled and partly controlled asthma, who maintained their original inhaled corticosteroids therapy, underwent reassessment of airway responsiveness and asthmatic symptoms 3 and 6 months after. Nineteen uncontrolled, 22 partly controlled and 19 controlled asthmatic patients and 24 healthy subjects were recruited. Lower PD 20 FEV 1 geometric means were associated with poorer asthma control in His-BPT (0.424 μmol vs 1.684 μmol vs 3.757 μmol), but not AMP-BPT (11.810 μmol vs 7.781 μmol vs 10.220 μmol). Both BPTs yielded similar overall diagnostic performance in asthma (area under curve: 0.842 in AMP-BPT vs 0.850 in His-BPT). AEs, including wheezing and tachypnea, were similar and mild. Ten patients with uncontrolled and 10 partly controlled asthma were followed-up. At months 3 and 6, we documented an increase in PD 20 FEV 1 -AMP and PD 20 FEV 1 -His, which did not correlate with reduction asthmatic symptom scores. This overall applied in responders and poor responders of AMP-BPT and His-BPT. Despite higher screening capacity of well-controlled asthma, AMP-BPT confers similar diagnostic performance and safety with His-BPT. AMP-BPT might not preferentially reflect changes asthmatic symptoms. © 2015 John Wiley & Sons Ltd.

Neurohemodynamic Correlates of Washing Symptoms in Obsessive-compulsive Disorder: A Pilot fMRI Study Using Symptom Provocation Paradigm

PubMed Central

Agarwal, Sri Mahavir; Jose, Dania; Baruah, Upasana; Shivakumar, Venkataram; Kalmady, Sunil Vasu; Venkatasubramanian, Ganesan; Mataix-Cols, David; Reddy, Yemmigannur Chandrashekhar Janardhan

2013-01-01

Background: Obsessive-compulsive disorder (OCD) is increasingly being viewed as a multidimensional heterogeneous disorder caused due to the dysfunction of several closely related, overlapping frontostriatal circuits. A study investigating the dimensional construct in treatment naïve, co-morbidity free patients with identical handedness is likely to provide the necessary homogeneity and power to elicit neural correlates of the various symptom dimensions, and overcome the limitations of previous studies. Materials and Methods: Nine DSM-IV OCD patients with predominant contamination-related obsessive-compulsive symptoms (age=29.8±7.1 years; five males: four females; years-of-education=13.9±1.6, YBOCS total score=28.8±4.7, DYBOCS Contamination dimension score=10.7±1.8) and nine healthy controls matched one to one with the patients for age, sex, and years of education (age=27.8±5.4, five males: four females; years-of-education=14.9±3.0), were examined during symptom provocation task performance in 3TMRI. Paired samples t test of brain activation differences (contamination relevant pictures – neutral pictures), limited to apriori regions of interest was done using SPM8 (uncorrected P<0.005). Results: Patients found significantly more pictures to be anxiety provoking in comparison to healthy controls. Patients were found to have deficient activation in the following areas in comparison with healthy controls: bilateral anterior prefrontal, dorsolateral prefrontal, orbitofrontal, anterior cingulate, insular and parietal cortices, precuneus, and caudate. Conclusions: Results underscore the importance of frontal, striatal, parietal, and occipital areas in the pathophysiology of OCD. Divergence of findings from previous studies might be attributed to the absence of confounding factors in the current study and may be due to production of intense anxiety in patients. PMID:23833345

389 Allergic Reactions to Local Anesthetics: Detection by Skin Tests and Subcutaneous Provocation. Analysis of 160 Cases

PubMed Central

Arcanjo, Luiz; Gonçalves Tavares, Tania Maria; Delcourt, Nathalia; Baroni, Juliana; Rios, João; Rios, José Luiz

2012-01-01

Background Adverse reactions to local anesthetics (LA) are frequent and often referred to as allergic. Although immune-mediated reactions are rare, it should be investigated for suspected cases. The objective of this study was to determine the frequency of positive skin test to these drugs in patients with a suspected history of allergic reactions and describe the main socio-demographic characteristics of these individuals. Methods Retrospective study of medical records of patients attended at Policlínica Geral do Rio de Janeiro Allergic Clinic, between 2008 and 2011. The parameters evaluated were the test indication and the patient ages and gender. The drug tested was that the patient had a history of suspicion. Patients underwent skin prick and intradermal tests and subcutaneous provocation. Descriptive statistical analysis of the data was performed. Results It was performed 160 tests (125 female). Three of this total was excluded due to inconclusive results. In women, the highest proportion of tests was in the age group from 41 to 60 years (43%), while in males the higher concentration was at a youngest age group: 21 to 40 years (41%). The most common indication (103 cases, 65%) for the tests was a previous suspected anaphylactic reaction by LA. Seven of 157 tests had a positive result (4.4%), 6 of them occurred in women (4.8%). Only one test resulted in a type of anaphylactic reaction response (0.67%). All patients who presented positive response to the test had a history of per-anesthetic reaction that suggested an immune-mediated mechanism. Conclusions In patients with a history of previous reaction to local anesthetics, the skin tests with these drugs have a key role in the prevention of anaphylaxis, and on guidance for adequate anesthetic procedures.

Running Reduces Uncontrollable Stress-Evoked Serotonin and Potentiates Stress-Evoked Dopamine Concentrations in the Rat Dorsal Striatum

PubMed Central

Clark, Peter J.; Amat, Jose; McConnell, Sara O.; Ghasem, Parsa R.; Greenwood, Benjamin N.; Maier, Steven F.; Fleshner, Monika

2015-01-01

Accumulating evidence from both the human and animal literature indicates that exercise reduces the negative consequences of stress. The neurobiological etiology for this stress protection, however, is not completely understood. Our lab reported that voluntary wheel running protects rats from expressing depression-like instrumental learning deficits on the shuttle box escape task after exposure to unpredictable and inescapable tail shocks (uncontrollable stress). Impaired escape behavior is a result of stress-sensitized serotonin (5-HT) neuron activity in the dorsal raphe (DRN) and subsequent excessive release of 5-HT into the dorsal striatum following exposure to a comparatively mild stressor. However, the possible mechanisms by which exercise prevents stress-induced escape deficits are not well characterized. The purpose of this experiment was to test the hypothesis that exercise blunts the stress-evoked release of 5-HT in the dorsal striatum. Changes to dopamine (DA) levels were also examined, since striatal DA signaling is critical for instrumental learning and can be influenced by changes to 5-HT activity. Adult male F344 rats, housed with or without running wheels for 6 weeks, were either exposed to tail shock or remained undisturbed in laboratory cages. Twenty-four hours later, microdialysis was performed in the medial (DMS) and lateral (DLS) dorsal striatum to collect extracellular 5-HT and DA before, during, and following 2 mild foot shocks. We report wheel running prevents foot shock-induced elevation of extracellular 5-HT and potentiates DA concentrations in both the DMS and DLS approximately 24 h following exposure to uncontrollable stress. These data may provide a possible mechanism by which exercise prevents depression-like instrumental learning deficits following exposure to acute stress. PMID:26555633

Regional flow simulation in fractured aquifers using stress-dependent parameters.

PubMed

Preisig, Giona; Joel Cornaton, Fabien; Perrochet, Pierre

2012-01-01

A model function relating effective stress to fracture permeability is developed from Hooke's law, implemented in the tensorial form of Darcy's law, and used to evaluate discharge rates and pressure distributions at regional scales. The model takes into account elastic and statistical fracture parameters, and is able to simulate real stress-dependent permeabilities from laboratory to field studies. This modeling approach gains in phenomenology in comparison to the classical ones because the permeability tensors may vary in both strength and principal directions according to effective stresses. Moreover this method allows evaluation of the fracture porosity changes, which are then translated into consolidation of the medium. © 2011, The Author(s). Ground Water © 2011, National Ground Water Association.

Heart rate stress response dampening: the impact of alcohol, family history, and gender on at risk children and siblings.

PubMed

Croissant, Bernhard; Demmel, Ralf; Rist, Fred; Olbrich, Robert

2011-04-01

In the following study we tested the stress response dampening (SRD) model which postulates that stress responses are more likely to be attenuated by alcohol in individuals at risk for alcohol dependence than in persons without that risk. In a laboratory experiment we examined a) if SRD effects exist for both sons and healthy daughters of alcohol dependent fathers, and b) if SRD effects exist for siblings of alcohol dependent males. We recruited 104 subjects at risk and 51 matched control subjects. In a laboratory experiment, study subjects received alcohol in one of two laboratory sessions and a stress paradigm served to elicit heart rate stress responses. Heart rate stress responses were attenuated by alcohol in female family history positive (FHP) and female family history negative (FHN) subjects, however not in males. A multiple regression analysis revealed "Heart Rate Stress Response in the Non-Alcohol Condition" and "Blood Alcohol Level" as significant predictors of SRD. According to our findings, females carry a distinct risk for developing alcohol dependence, regardless of their family history and regardless of their degree of familial relationship. This is an important issue for devising models concerning the development and maintenance of alcohol dependence in females. The study extends the current research literature, which mainly focuses on male subjects at risk, by including female subjects at risk, as well as siblings at risk of both genders. Copyright © 2011 Elsevier B.V. All rights reserved.

Theory and Test of Stress Resistance

DTIC Science & Technology

1992-04-01

example, the word death has its effect on the ink colour blue and not green. The main assumption made by this model is that the two effects can be...CODE Approved for public release; distribution is unlimited. 13. ABSTRACT (Max:mum 200 words) In this report, we developed a laboratory model to test...this point, been acknowledged. The research also points to two (Continued) 14. SUBJECT TERMS 15. NUMBER OF PAGES Stress resistance Attention 48